2000 A NNUAL

P ROGRESSR EPORT

U.S. Department of Energy

Energy Efficiency and Renewable Energy

Office of Transportation Technologies

FUELS FOR ADVANCED CIDI ENGINES

AND FUEL CELLS

FUELS FOR ADVANCED CIDI ENGINES

AND FUEL CELLS

2000 ANNUAL PROGRESS REPORT FUELS FOR ADVANCED CIDI ENGINES AND FUEL CELLS
ACKNOWLEDGEMENT

We would like to express our sincere appreciation to Argonne National

Laboratory, Computer Systems Management, Inc., National Renewable

Energy Laboratory, and QSS Group, Inc., for their artistic and technical 

contributions in preparing and publishing this report.

In addition, we would like to thank all our program participants for their

contributions to the programs and all the authors who prepared the 

project abstracts that comprise this report.
U.S. Department of Energy

Office of Transportation Technologies

1000 Independence Avenue, S.W.

Washington, DC 20585-0121

FY 2000

Progress Report for Fuels for Advanced CIDI 

Engines and Fuel Cells

Energy Efficiency and Renewable Energy

Office of Transportation Technologies

Approved by Steven Chalk

November 2000
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

CONTENTS

 Page

iii

I. INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

II. FUEL & LUBRICANT EFFECTS ON CIDI ENGINE EMISSIONS . . . . . . . . . . . . . . . . . .11

A. Phase II Testing of Advanced Petroleum-Based Fuels in a State-of-the Art CIDI Engine . . . . . . . . . . . . . . . . . 11

B. Oxygenates for Advanced Petroleum-Based Diesel Fuels. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

C. Production of Transportation Fuel from C1 Chemistry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

D. Modeling of Soot and NOx Formation from Combustion of Oxygenated Fuels in CIDI Engines . . . . . . . . . . . 26

E. In-Cylinder Imaging of Advanced Diesel Fuel Combustion in a CIDI Engine. . . . . . . . . . . . . . . . . . . . . . . . . . 30

F. Impact of Consumed Lube Oil on Advanced CIDI Engine Emissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

III.FUEL & LUBRICANT EFFECTS ON EXHAUST EMISSION CONTROL DEVICES . .41

A. Overview of the Diesel Emission Control-Sulfur Effects (DECSE) Program, Phase I. . . . . . . . . . . . . . . . . . . . 41

B. NOx Adsorber Testing with Fuels of Varying Sulfur Content . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

C. Evaluation of Advanced Petroleum-Based Fuels in a Mercedes Benz "C" Class CIDI Vehicle. . . . . . . . . . . . . 52

D. NOx and PM Emission Control Device Evaluation in a Mercedes-Benz 1.7L CIDI Vehicle. . . . . . . . . . . . . . . 57

E. EC-Diesel Technology Validation Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

F. Systems Emission Reduction (SER) Analysis for Automobiles, Light Trucks, and Heavy-duty Engines . . . . . 65

IV. HEALTH & SAFETY, MATERIALS COMPATIBILITY, ECONOMICS, AND 

DISSEMINATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .69

A. Environmental Performance of Oxygenated Fuel Compounds Used in Advanced Petroleum-Based Fuels. . . . 69

B. Chemical Characterization of Toxicologically Relevant Compounds From Diesel Emissions . . . . . . . . . . . . . 73

C. Comparing and Contrasting Particle Emissions from Spark Ignition and Compression Ignition Engines . . . . . 81

D. Lubricity of High Volatility, Low Sulfur CIDI Fuels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

E. Refinery Modeling of the Production of Advanced Petroleum-Based Fuels. . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

F. Fuel Property and Emissions Database . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

V. ADVANCED FUELS FOR FUEL CELLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .97

A. Fuel Composition Effects on Fuel Processing Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

B. Effects of Fuel Constituents on Fuel Processor Catalysts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

C. Sulfur Removal from Reformate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

D. The California Fuel Cell Partnership . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

1

I. INTRODUCTION

Enabling Advanced Vehicle Technologies through Development and Utilization of Advanced 

Petroleum-Based Fuels

On behalf of the Department of Energy’s Office of Transportation Technologies 

(OTT), we are pleased to introduce the Fiscal Year (FY) 2000 Annual Progress 

Report for the Fuels for Advanced CIDI Engines and Fuel Cells Program. Together 

with DOE National Laboratories and in partnership with private industry and 

universities across the United States, OTT engages in high risk R&D that provides 

enabling technology for fuel efficient and environment-friendly vehicles. The 

Program is currently focused on advanced fuels for the 

compression-ignition, direct injection (CIDI) engine, an 

advanced version of the commonly known diesel engine, 

which is used in both light- and heavy-duty vehicles. 

Because OTT conducts fuels R&D for CIDI engines in both 

the Office of Advanced Automotive Technologies (OAAT) 

and the Office of Heavy Vehicle Technologies (OHVT), they 

have developed a joint multiyear program plan1

, called the 

Advanced Petroleum-Based Fuels (APBF) RD&T for CIDI 

Engines and Emission Control Systems. This year’s progress 

report includes all the projects conducted in support of the 

APBF Program. Fuels R&D is also coordinated with the 

Combustion and Emission Control R&D for Advanced CIDI 

Engines and Transportation Fuel Cell Power Systems 

Programs (which have their own separate reports), which 

rely on this Program for fuels that will enable them to meet 

their out-year objectives.

The Fuels for Advanced CIDI Engines and Fuel Cells Program supports the 

Partnership for a New Generation of Vehicles (PNGV), an industry-government 

partnership that aims to develop, by 2004, a mid-sized passenger vehicle capable of 

achieving 80 miles per gallon while adhering to future emissions standards and 

maintaining such attributes as affordability, performance, safety, and comfort. In 

order for PNGV-selected powertrains and energy conversion technologies to 

maximize their potential in energy efficiency while maintaining low emissions, 

advanced fuels are needed and serve as key technology enablers. The work in 

advanced petroleum-based fuels is conducted through joint programs with the energy and automotive 

industries. Advanced petroleum-based fuels will also be an asset to the 21st Century Truck Initiative that 

proposes to triple medium-duty truck fuel economy and double heavy-duty truck fuel economy on a ton-mile 

per gallon basis. In FY 2000, the APBF Program was focused on developing and testing advanced fuels for 

use in CIDI engines and transportation fuel cell power systems.

This report highlights progress achieved during FY 2000, and comprises 22 summaries of industry and 

National Laboratory projects that were conducted. It provides an overview of the exciting work being 

1 Multiyear Program Plan, Advanced Petroleum-Based Fuels (APBF) RD&T for Compression-Ignition, Direct Injection 

Engines and Emission Control Systems, DOE Office of Advanced Automotive Technologies and Office of Heavy Vehicle Technologies, November 1, 2000.

Pete Devlin, Program 

Manager, Fuels for Fuel 

Cells and Advanced 

CIDI Engines 

Steve Goguen, Team 

Leader, Fuels and 

Lubricants for HeavyDuty Applications

John Garbak, Program 

Manager, Fuels for 

Advanced CIDI Engines 

and Fuel Cells
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

2

conducted to tackle the tough technical challenges associated with developing clean burning fuels that will 

enable meeting the performance goals of the Emission Control R&D for Advanced CIDI Engines and the 

Transportation Fuel Cell Power Systems Programs. The summaries cover the effects of fuels on CIDI engine 

emissions and fuel cell power system performance, the effects of lubricants on engine emissions, the effects of 

fuels and consumed lubricants on exhaust emission control devices, and the health and safety, materials 

compatibility, and economics of advanced petroleum-based fuels. A brief snapshot of FY 2000 

accomplishments and new program directions for FY 2001 is captured in the following pages. We are 

encouraged by the technical progress realized under this dynamic program in FY 2000 and look forward to 

making further advancements in FY 2001.

Advanced petroleum-based fuels are a critical enabler to allow the high fuel economy of dieselpowered vehicles to be maintained while meeting future emission standards

Two major regulatory events occurred during the past year: first, 

the Environmental Protection Agency (EPA) Tier 2 light-duty vehicle 

emission regulations were finalized which requires low sulfur gasoline 

(30 ppm average; 80 ppm maximum) and very low emissions for both 

spark ignition and diesel light-duty vehicles (0.07 g/mile NOx fleet 

average, 0.01 g/mile PM for most light-duty vehicles). Second, EPA 

proposed new emission regulations for heavy-duty diesel engines (0.2 

g/bhp-hr NOx and 0.01 g/bhp-hr PM) that will require exhaust 

emission control devices and very low sulfur diesel fuel (EPA has 

proposed 15 ppm maximum). Exhaust emission control devices 

needed for heavy-duty engines to meet the proposed EPA emission 

standards will also be needed by light-duty diesel vehicles to meet the 

Tier 2 regulations. Advanced petroleum-based fuels will ensure that 

the high fuel economy benefits of advanced CIDI engines are realized 

while enabling the effectiveness and durability of emission control devices over their full useful life.

While CIDI engines are viewed as a nearer-term opportunity to meet the 80 mpg objective set by PNGV, 

fuel cells are seen as a promising longer-term technology that will be capable of achieving unprecendented fuel 

economy with zero or near-zero emissions. One of the key challenges of producing a fuel cell vehicle is 

developing an appropriate fuel for vehicular applications. Fuel cells can potentially use a wide range of fuels 

such as hydrogen, methanol, ethanol, natural gas, and gasoline. The fuels effort to support the Transportation 

Fuel Cell Power Systems Program is currently focused on determining the effects of petroleum fuel 

contaminants on the fuel cell system performance and developing advanced petroleum-based fuels and catalyst 

technologies that will not compromise the fuel cell’s inherently high efficiency.

SIGNIFICANT FY 2000 ACCOMPLISHMENTS

In FY 2000, much effort has been devoted to determining the effect of fuel sulfur content on CIDI NOx and 

PM emission control devices. While it is still unclear what maximum level of sulfur might be acceptable, the 

testing conducted in FY 2000 indicated that very low levels of sulfur content are likely to be required for CIDI 

vehicles and heavy-duty engines to meet the full useful life Tier 2 and proposed heavy-duty engine emission 

standards. Both NOx and PM emission control devices will have to achieve conversion efficiencies of 80 to 95 

percent so that light-duty vehicles with CIDI engines and heavy-duty CIDI engines will be able to meet the 

emission standards. In addition, testing of some oxygenated diesel fuels showed potential for lowering both 

NOx and PM emissions, and to have some favorable characteristics to complement the operation of exhaust 

emission control devices. These tests are on-going using state-of-the-art and prototype CIDI engines, and the 

latest exhaust emission control devices, and a Multiyear Program Plan has been completed to guide this 

Advanced Petroleum-Based Fuels Will 

Enable Advanced Engines, Emission 

Control Systems, and Fuel Cells
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

3

research through 2004. In the fuel cell area, work is 

progressing on identifying the effects of fuel composition 

on fuel processor performance, and on means of removing 

sulfur from the fuel which would otherwise poison the 

fuel cell. In FY 2000, DOE began its work with the 

California Fuel Cell Partnership. The overall objective of 

the Partnership is to demonstrate the practicality of fuel 

cell vehicles, initially operating with hydrogen as fuel. 

The following lists the highlights of research and testing 

conducted in the APBF Program during FY 2000.

Advanced Petroleum-Based Fuels for CIDI 

Engines

• The National Renewable Energy Laboratory provides 

coordination and technical support to the Diesel 

Emission Control-Sulfur Effects (DECSE) program 

that conducted engine dynamometer tests of the 

effects of fuel sulfur on several exhaust emission 

control devices. The DECSE program was funded 

jointly by industry through the Engine Manufacturers 

Association and the Manufacturers of Emission 

Controls Association. Oak Ridge National 

Laboratory was also part of the team and FEV was 

contracted to perform the engine dynamometer 

testing. The NOx emission reduction devices tested 

included lean-NOx catalysts and NOx adsorber 

catalysts. The PM emission reduction devices tested 

included oxidation catalysts, continuously 

regenerating particulate filters (CR-DPF), and 

catalyzed diesel particulate filters (CDPF). The fuel 

used was similar to conventional diesel fuel except 

for sulfur content. Sulfur contents tested included 3, 

16, 30, 150, and 350 ppm. Some of the major 

findings of this work include:

- Lean-NOx catalysts do not have sufficient 

conversion efficiency at this time.

- NOx adsorber catalysts show promise when used 

with 3 ppm sulfur fuel, but their efficiency 

degrades rapidly with 16 and 30 ppm sulfur level 

fuels (see figure).

- Diesel oxidation catalysts (DOC) have moderate 

capability to reduce PM emissions, but create 

significant sulfate PM at fuel sulfur levels above 

30 ppm (see figure).

- Both CR-DPFs and CDPFs have very high PM 

removal efficiency (95%) when using 3 ppm 

sulfur fuel. The PM removal efficiency (i.e. filter 

Effect of Fuel Sulfur Level on an Engine Dynamometer 

Test of an NOx Adsorber (DC/DDC 1.9L Prototype 

Engine, steady state testing)

Effect of Fuel Sulfur Level on DOC PM Emissions in 

Steady-State Heavy-Duty Engine Dynamometer Tests 

(Cummins ISM370 Engine)

Effect of Fuel Sulfur Level on PM Emissions of a CDPF 

and CR-DPF in Steady-State Heavy-Duty Engine 

Dynamometer Tests (Caterpillar 3126 Engine)
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

4

emissions compared to engine-out emissions) 

degrades significantly when using 30 ppm 

sulfur fuel (72-74%) and drops nearly to zero 

efficiency when using 150 ppm sulfur fuel 

(see figure).

- In the DOC and PM filter tests, the sulfur 

present in the fuel is converted to sulfate PM 

at the rate of 40% to 50%, and regeneration 

temperatures increase with increase in fuel 

sulfur level.

• A second phase of the exhaust emission control 

device testing described above (DECSE-II) 

focused on improving the regeneration strategy of 

the NOx adsorber and development and 

demonstration of a process to remove 

accumulated sulfur from the adsorber following 

extended operation. It was shown that, with the 

proper engine calibration, the NOx conversion 

efficiency of the NOx adsorber could be improved 

to over 90 percent in the temperature range of 

300o

C to 450oC, which suggests that NOx

adsorbers (with further successful development) 

could allow light-duty vehicles to meet the Tier 2 

fleet average of 0.07 g/mile NOx. It was shown 

that the fuel required for regeneration was 

estimated to cause a 4 percent decline in fuel 

economy. It was also shown that sulfur 

accumulated on the NOx adsorber could be 

removed by subjecting the adsorber to 700o

C 

temperatures achieved using post injection, a 

warm-up catalyst upstream of the adsorber, 

throttling, and EGR. While such strategies hold 

promise to achieve the Tier 2 NOx fleet average, 

several hurdles remain, including the fuel 

economy penalty incurred and the thermal 

stability of the catalyst to repeated 

desulfurizations.

• The Oak Ridge National Laboratory explored the 

potential of near-term NOx and PM exhaust 

emission control devices on a small state-of-theart CIDI passenger car (Mercedes A170) using 

fuel with 3, 30, and 150 ppm sulfur content. A 

NOx adsorber catalyst and a catalyzed diesel 

particulate filter were tested independently on the 

vehicle over the Federal Test Procedure (FTP) 

(see figures). These tests demonstrate the 

capability to meet the Tier 2 fleet average NOx

emission standard of 0.07 g/mile using the 3 ppm 

ORNL Researchers Conducting Chassis Dynamometer 

Tests on the Mercedes A170

Mercedes A170 NOx FTP Emissions Using an NOx Adsorber 

and Various Fuel Sulfur Contents

Mercedes A170 FTP Emissions Using a CDPF and Various 

Sulfur Content Fuels with No Advanced NOx Control Device
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

5

sulfur content fuel when the catalyst was relatively new. However, limited durability testing suggests that 

this device would not meet full useful life standards even when using 3 ppm sulfur content fuel. The 

catalyzed diesel particulate filter was much less affected by fuel sulfur content and PM emissions were 

always below 0.01 g/mile. Though these results are very promising, some hurdles remain before such 

systems could be considered feasible for use: reducing the amount of reductant needed to regenerate the 

NOx adsorber, designing the reductant preparation and delivery system, and reducing the regeneration 

temperature of the catalyzed diesel particulate filter.

• The National Renewable Energy Laboratory managed a 

field test of conventional diesel vehicles using a lowsulfur, low-aromatic diesel fuel and retrofitted with 

catalyzed particulate filters. The fuel is made by BP 

Amoco and is called EC-Diesel. EC-Diesel has a 

maximum sulfur content of 15 ppm, less than 10% 

aromatics by volume, and a nominal cetane rating of 60. 

BP Amoco has intentions to make EC-Diesel available in 

Southern California. Eight vehicle fleets participated, all 

having vehicles with modern, electronically-controlled 

diesel engines. Two catalyzed particulate filters were 

supplied by Engelhard and Johnson-Matthey and one of 

them was retrofitted to each of the vehicles. The vehicles 

were tested for emissions using the University of West 

Virginia mobile chassis dynamometer. The combination of ultra low sulfur and low aromatic fuel with the 

retrofitted catalyzed particulate filters resulted in extremely low PM and hydrocarbon emissions, 

sometimes indistinguishable from background values (see figure). Emissions of NOx were not affected. 

Testing will be conducted at regular intervals to determine how emissions might deteriorate over time.

• Sandia National Laboratory (SNL) and Lawrence Livermore National Laboratory (LLNL) continued 

projects to understand the fundamental mechanisms of particulate and NOx formation during combustion. 

SNL is using in-cylinder imaging of the combustion of fuels with varying levels of particulate production 

to identify where and how particulates are formed. LLNL is applying the chemical kinetics of combustion 

to identify the reactions that produce particulates and NOx, and how the addition of oxygenates affects the 

formation of both.

• As emissions of PM from CIDI engines are reduced, the 

contribution of PM from consumed lubricating oil 

becomes more important (compared to PM from fuel). 

Testing conducted by Southwest Research Institute 

(SwRI) showed that PM is reduced by 19% when using 

5W30 mineral oil instead of a 15W50 synthetic oil 

(Mode 10 steady-state operation representative of 

typical light-duty vehicle engine load, see Figure) when 

using CARB diesel fuel. SwRI also found that 27 

percent of the PM at Mode 10 was caused by oil 

consumption (using 5W30 mineral oil) when using 

CARB diesel fuel. Synthetic oils and high boiling point 

oils reduce the contribution to PM emissions. High 

friction oils also reduce PM emissions, but at the 

expense of higher NOx emissions. This work suggests 

that particulate emissions can be significantly reduced 

through oil formulation, without impact on other emissions.

Average Grocery Truck Emissions over the CitySuburban Heavy Vehicle Route

Fractionated Particulate Showing Fuel and Oil 

Contributions to PM (CARB Fuel; 5W30 Baseline 

Mineral Oil)
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

6

• In FY 1999, blends of oxygenates in diesel fuel showed potential for very large decreases in PM emissions 

(50%) with small decreases in NOx emissions. However, some of these oxygenate blends were not 

practical for use in the current distribution system, or presented potential safety or materials compatibility 

problems. Southwest Research Institute managed a project with oversight and direction from auto and 

energy companies to identify oxygenates that can be used in diesel fuel which may not cause infrastructure 

or compatibility problems, and might be economical for use as a blending component. Seventy-one 

oxygenates were screened and six were chosen for more in-depth evaluation. Of these six, two have been 

selected for comprehensive engine testing in FY 2001.

• Through modeling of the typical U.S. refinery, 

Oak Ridge National Laboratory estimated that 

reducing the sulfur in on-road diesel fuel to 15 

ppm, as proposed by EPA, would add 7 to 8 cents 

per gallon to the average cost of production. The 

marginal cost of sulfur removal increases rapidly 

for fuel sulfur contents of 25 ppm and lower (see 

Figure). 

• Three projects were undertaken during FY 2000 

to evaluate the health and safety impacts of CIDI 

fuels and emissions. The Lawrence Livermore 

National Laboratory developed a systematic 

methodology to assess the environmental impact 

of oxygenated fuel components for potential use 

in advanced petroleum-based diesel fuels. The 

methodology includes transport and degradation 

models to evaluate the relative hazards caused by 

spills, and prediction of human exposure via ingestion, inhalation, and dermal uptake. In a project being 

conducted by Southwest Research Institute, the effects of fuels on the engine-out emissions of potentially 

toxicologically relevant compounds are also being determined. In a project being conducted by the Oak 

Ridge National Laboratory, transmission electron microscopy and real-time aerosol mass spectroscopy are 

being used to compare the structure and composition of PM from both gasoline and diesel vehicles. Using 

these instruments, the chemical composition of both the surface of the PM and the core of the PM will be 

identified.

Advanced Fuels for Fuel Cells

• Hydrogen is acknowledged to be the long-term 

fuel cell fuel, and fuels that are compatible with 

the existing petroleum fuel infrastructure are the 

likely transition step toward that goal. The 

Argonne National Laboratory (ANL) is exploring 

how different hydrocarbons affect reformer 

performance, with the overall objective of 

identifying which gasoline constituents cause 

degradation of fuel cell systems (see Figure). 

Through this project, ANL will work with energy 

companies to identify how the constituents that 

cause problems can be minimized, while 

maintaining compatibility with the present 

petroleum fuel distribution system. The progress 

this project has made this year includes:

Effect of Temperature on Hydrogen Yield from Autothermal 

Reforming of Gasoline Constituents

Estimated Production Cost Increase for Reformulated Diesel 

(RFD)
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

7

- completion of short-term testing of six gasoline components;

- completion of long-term tests on iso-octane and two benchmark fuels; and

- initiation of tests on the effect of fuel sulfur content.

• The Los Alamos National Laboratory (LANL) is exploring ways to improve fuel cell reformer durability 

and lifetime, reduced volume, improved performance, and other improvements required to meet fuel 

processor goals. LANL is focusing on improved catalyst formulations to achieve these reformer 

improvements. The accomplishments they have made in the past year include:

- automation of the test facility to complete 

multiple tests quickly and efficiently;

- initiated testing of a fuel-flexible fuel processor 

and verified operation using natural gas;

- initiated testing of liquid fuels; and

- showed that 100 ppm sulfur in the fuel, using a 

specific fuel processor and catalyst, reduced 

hydrogen production by 75 percent (see 

Figure).

• One of the largest hurdles to using hydrocarbons for 

fuel cell vehicles is that the sulfur contained in 

gasoline today will poison the reformer and fuel 

cell catalysts. The Argonne National Laboratory 

(ANL) is exploring ways to remove this sulfur and 

define the tolerance of both reformers and fuel cells 

to fuel sulfur content. A zinc-oxide absorption bed 

has been fabricated and it has demonstrated the 

capability to decrease H2S concentration in a 

reformate stream from10-30 ppm down to less than 

1 ppm. 

• The California Fuel Cell Partnership will 

demonstrate fuel cell technology by operating and 

testing fuel cell vehicles in California. The first 

vehicles demonstrated will use hydrogen as fuel. In 

a later phase of the demonstration, fuel cell vehicles 

may also use methanol and gasoline as fuel. To 

date, fleets have been identified to use the initial 

fuel cell vehicles and a hydrogen refueling facility 

has been designed. 

FUTURE INITIATIVES

Our new program initiatives for FY 2001 build upon the progress made in FY 2000 and will focus on those 

areas that industry agrees are major technical barriers.

Ultra-Clean Transportation Fuels Initiative

• In FY 2001, the Ultra-Clean Transportation Fuels Initiative, which is a new initiative jointly funded by the 

Office of Energy Efficiency and Renewable Energy and the Office of Fossil Energy, will begin to research 

Hydrogen Production from Iso-octane and Iso-octane with 

100 ppm Sulfur

California Governor Gray Davis Announces the California 

Fuel Cell Partnership at the State Capitol on April 20, 

1999
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

8

and develop advanced fuels, refinery processes, and vehicle emission control technologies. The advanced 

fuels technology will produce ultra-clean burning, high performance fuels from a diversity of resources in 

addition to conventional petroleum. These fuels will be used to support the research and development of 

innovative vehicle emission control systems with ultra-low NOx and particulate matter emissions.

Advanced Petroleum-Based Fuels for CIDI Engines

• Quantify the effect of fuel sulfur content on exhaust emission control device durability in terms of 

deterioration rate, ability to "rebound" from exposure to high sulfur fuels, and the impact on fuel economy 

penalty for regeneration and desulfurization.

• Conduct vehicle tests of integrated NOx and PM emission control devices using fuels with several sulfur 

levels to predict the capability of these systems to meet Tier 2 and proposed heavy-duty engine emission 

standards.

• Begin testing various selective catalytic reduction (SCR) systems to determine their conversion efficiency 

and effectiveness at various sulfur contents.

• Study the potential to reduce the fuel economy penalty of regenerating and desulfurizing NOx adsorbers.

• Complete comprehensive testing of the two most promising oxygenates chosen of the seventy-one which 

were screened.

• Develop and test models for PM and NOx formation during combustion and extend these models to 

incorporate oxygenated fuel components.

• Perform additional testing of the vehicles in the demonstration of EC-Diesel.

• Define environmental parameters for development of screening models for oxygenated diesel fuel 

components.

• Measure the effect of exhaust emission control devices using several clean diesel fuels on emissions of 

toxics.

• Analyze the effects of phased market introduction on the price and availability of ultra low sulfur diesel 

fuel.

Advanced Fuels for Fuel Cells

• Study the effects of fuel constituents (focusing on olefins, napthalenes, and substituted aromatics that may 

be problematic), additives, and impurities on fuel processor operation.

- Measure fuel processor transient operation including startup and shutdown and variations in flow 

rates.

- Monitor carbon formation in situ by use of adiabatic reactor and laser scattering.

- Map carbon formation of individual fuel constituents with operating conditions.

• Investigate the effect of sulfur on various fuel processor catalysts.

• Evaluate the capability of new structured forms of ZnO to remove H2S from reformate streams.

• Initiate operation of fuel cell vehicles in California and identify additional refueling sites; identify 

additional fuels to test; assess commercialization issues; and implement public outreach and education 

plans.
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

9

HONORS AND SPECIAL RECOGNITIONS

• The California Fuel Cell Partnership received the "Blue Sky Innovation AwardTM" from CALSTART for 

taking early steps to create a fuel cell market by demonstrating fuel cell vehicles in California.

• The team that prepared the Multiyear Program Plan for Advanced Petroleum-Based Fuels was recognized 

with a special achievement award at the CIDI Engine Combustion, Emission Control, and Fuels Review 

held at Argonne National Laboratory May 22-24, 2000. The team included representatives from the 

National Renewable Energy Laboratory, Argonne National Laboratory, Oak Ridge National Laboratory, 

Southwest Research Institute, Energetics, and QSS Group, Inc.

SUMMARY

Advanced petroleum-based fuels enable the use of high efficiency powerplants such as CIDI engines and 

fuel cells to create fuel efficient light-duty and heavy-duty vehicles with the attributes that consumers demand. 

Fuel efficient vehicles with very low emissions are essential to meet the challenges of climate change, energy 

security, and improved air quality. The work being conducted on advanced petroleum-based fuels 

complements the efforts to build advanced engines and fuel cells while recognizing that the engine/fuel/

emission control system must work together to achieve the maximum benefits possible. As the new fiscal year 

begins, we look forward to on-going and new cooperative efforts with the auto and energy industries to 

develop new and innovative technologies that will be used to make advanced transportation vehicles that are 

fuel efficient, clean, and safe.

John A. Garbak, Program Manager Peter R. Devlin, Program Manager

Advanced Petroleum-Based Fuels Advanced Petroleum-Based Fuels

Office of Advanced Automotive Technologies Office of Advanced Automotive Technologies

Office of Transportation Technologies Office of Transportation Technologies

Stephen J. Goguen, Team Leader

Heavy-Duty Fuels and Lubricants

Office of Heavy Vehicle Technologies

Office of Transportation Technologies
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

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Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

11

II. FUEL & LUBRICANT EFFECTS ON CIDI ENGINE EMISSIONS

A. Phase II Testing of Advanced Petroleum-Based Fuels in a State-of-the Art CIDI 

Engine

Ed C. Owens (primary contact) and D.M. Yost

Southwest Research Institute

6220 Culebra Road

San Antonio, TX 78238-5166

(210) 522-2577, fax: (210) 522-3270, e-mail: eowens@swri.org

DOE Program Manager: John Garbak

(202) 586-1723, fax: (202) 586-9811, e-mail: john.garbak@ee.doe.gov

This Project addresses the following OTT R&D Plan Barriers and Tasks:

Barriers

A. Fuel Property Effects on Engine Emissions and Efficiency

Tasks

2. Fuel and Lubricant Properties - Engine-Out Emissions

Objective

• Quantify exhaust emission benefits of selected advanced petroleum-based fuels in an advanced 

automotive diesel engine, with the engine optimized to take advantage of the individual combustion 

characteristics of each individual fuel.

Approach

• Three fuels shown to significantly reduce engine out emissions in the DaimlerChrysler OM611 CIDI 

engine during the first phase of this program, along with fuels suggested by the Ad-Hoc fuels working 

group, were evaluated for emissions benefits with selected engine control system optimization for each 

fuel.

• Engine-out emissions (no exhaust emission control devices) and performance were determined at a 

series of steady-state test modes.

• A partial factorial design of experiment approach was to develop a quadratic response surface model 

for PM, NOx and fuel consumption at each speed/load point as a function of the four engine operating 

parameters. The resulting surface would then be used to find optimum engine control conditions to 

achieve desired emission goals.

Accomplishments

• The engine’s OEM electronic controller was replaced with a SwRI Rapid Prototyping Electronic 

Control System (RPECS). The engine calibration tables and control signals were duplicated with the 

RPECS hardware/software, then modified as necessary.

• A partial factorial experimental design was developed to provide a quadratic response surface model 

for PM, NOx and fuel consumption at each speed/load point as a function of the four engine operating 

parameters.
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

12

• The resulting response surface model, when completed, did not adequately model the engine-out 

emissions. However, examination of the collected data clearly showed that reductions in both NOx and 

PM from the OEM conditions were achievable.

• Starting from the Ad-Hoc fuels working group test points, which specify the timing of peak cylinder 

pressure and EGR, a series of measurements of NOx and Bosch smoke measures were made with 

increasing levels of EGR. Bosch smoke has been correlated with particulate, and is a quicker 

measurement to make.

• Preliminary results, comparing emissions with alternative low-sulfur fuel (ALS) and with a fuel blend 

of 15% dimethoxymethane in ALS (ADMM15), show a clear difference in NOx and Bosch smoke 

level. At any smoke level, ADMM15 produces lower NOx emissions, but requires a higher level of 

EGR. This result is consistent with previous observations of the lower PM production at constant 

EGR levels.

Future Directions

• Correlations between Bosch smoke number and particulate are being developed for the fuels being 

evaluated. These will be used to assess the observed emission responses.

Introduction

This work is a follow-on to the Phase I fuel 

evaluations utilizing the DaimlerChrysler OM611 

CIDI engine. The Phase I testing was designed to 

evaluate the potential benefits of several alternative 

diesel fuels without making any adjustments to the 

engine control system. The objective of this second 

phase of work is to optimize the OM611 engine for a 

subset of the seven fuels that were tested in Phase I, 

as well as fuels recommended by the Auto/Energy 

Ad-Hoc committee.

Because the fuels under consideration have 

differing physical and chemical properties, a portion 

of any change in exhaust emissions measured in 

Phase I may be due to the response of the engine’s 

fuel injection system to differences in the fuel’s 

physical properties. This phase will recalibrate the 

engine operating parameters that influence engine 

emissions and fuel economy. These operating 

parameters include boost level, exhaust gas 

recirculation (EGR), fuel injection timing, and 

pressure in the common rail injection system.

Approach

Three fuels shown to significantly reduce 

engine-out emissions in the DaimlerChrysler OM611 

CIDI engine during the first phase of this program, 

along with fuels suggested by the Ad-Hoc fuels 

working group, were evaluated for emissions 

benefits with selected engine control system 

optimization for each fuel.

A partial factorial design of experiment approach 

was to develop a quadratic response surface model 

for PM, NOx and fuel consumption at each speed/

load point as a function of the four engine operating 

parameters. The resulting surface would then be 

used to find optimum engine control conditions to 

achieve desired emission goals. Engine-out 

emissions (no emission control devices) and 

performance were to be determined at a series of 

steady-state test modes.

In order to deviate from the factory engine 

operating settings, the engine’s OEM electronic 

controller was replaced with a SwRI Rapid 

Prototyping Electronic Control System (RPECS). 

The engine calibration tables and control signals 

were duplicated with the RPECS hardware/software, 

then modified as necessary. A high and a low value 

of each of the four engine operating parameters were 

determined by individually varying each parameter 

until one of the following occurred: a 20% NOx

increase was noted, a 20% increase in Bosch smoke 

was noted, the engine operated roughly, or exhaust 

temperature exceeded 1450o

F.
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

13

Results

The resulting response surface model, when 

completed, did not adequately model the engine-out 

emissions. Analysis of the statistical results suggest 

that the operating extremes generated by combining 

already broadly varied control settings resulted in 

engine responses that varied more "steeply" than the 

selected model would represent with adequate 

accuracy. However, examination of the collected data 

clearly showed that reductions in both NOx and PM 

from the OEM conditions were achievable.

Evaluation of the fuels was then conducted at the 

conditions developed by the Ad-Hoc fuels study 

group. The fuel injection rail pressure [injection rate] 

and turbocharger boost pressures were set at OEM 

conditions, EGR was set at a fixed rate dependent on 

speed and torque, pilot injection was disabled, and 

the beginning of injection timing was adjusted to 

locate peak combustion pressure at 7 degrees after 

top center. The data presented in Figure 1 were 

averaged over Modes 5, 6, 10, and 11 from both 

studies, since this Phase II work was conducted with 

a reduced number of operating modes. Because of 

fuel batch changes, only two fuels were actually 

identical between the two studies: the 2D 

certification fuel and the FT100 Fischer-Tropsch 

product. The arrows illustrate the impact of the 

engine control change on the emissions of these two 

fuels. This engine control strategy decreased 

particulate but increased NOx emissions. Starting 

from these operating conditions, the EGR rate was 

increased with ALS and ADMM15 at two operating 

modes: 6 and 11. A series of measurements of NOx

and Bosch smoke were made with increasing levels 

of EGR. Bosch smoke has been correlated with 

particulate, and can be measured more quickly.

Preliminary results, comparing emissions 

between ALS and ADMM15, show a clear difference 

in NOx and Bosch smoke level (Figure 2). At any 

smoke level, ADMM15 produces lower NOx

emissions but requires a higher level of EGR. This 

result is consistent with previous observations of the 

lower PM production at constant EGR levels and 

suggests that NOx reductions of 30 percent or more 

are possible at equal PM levels with ADMM15.

Correlations between Bosch smoke number and 

particulate are being developed for the fuels being 

evaluated. These will be used for assessment of the 

observed emission responses.

Conclusions

These results illustrate both the impact of engine 

control strategy on engine-out emissions, and the 

substantial impacts that changes in fuel formulation 

can have on engine-out particulate emissions. These 

preliminary results with ALS and ADMM15 indicate 

that because oxygenated fuels produce lower 

particulate levels, there is flexibility to operate the 

engine at higher EGR levels to reduce the engine out 

NOx emissions. However, since these initial data do 

not agree with data from the Ad-Hoc fuels working 

group, additional substantiation is needed.

Figure 1. Control Strategy Impacts on NOx and PM 

Emissions Figure 2. EGR Effect on NOx and Bosch Smoke
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

14

List of References

1. Sirman, M.B, Owens, E.C., and Whitney, K.A., 

"Emissions Comparison of Alternative Fuels in 

an Advanced Automotive Diesel Engine," 

Interim Report TFLRF No. 338, November 

1998.

List of Acronyms

2D EPA Certification Fuel

ADMM15 15% by volume dimethoxymethane 

blended in alternative low sulfur fuel

ALS Alternative Low-Sulfur

BSN Bosch Smoke Number

CA California Reference Diesel Fuel 

(Supplier A)

CARB California Reference Diesel Fuel 

(Supplier B)

CIDI Compression Ignition/Direct 

Injection

DMM15 15% by volume dimethoxymethane 

blended in low-sulfur fuel

EGR Exhaust Gas Recirculation

FT100 Fischer-Tropsch Fuel

LS Low-Sulfur Fuel

NOx Nitrogen Oxide

OEM Original Equipment Manufacturer

PM Particulate Matter

PNGV Partnership for a New Generation of 

Vehicles

RPECS Rapid Prototyping Electronic 

Control System

SwRI Southwest Research Institute
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

15

B. Oxygenates for Advanced Petroleum-Based Diesel Fuels

Dr. David Naegeli (primary contact), Ed C. Owens, Edwin A. Frame

Southwest Research Institute

6220 Culebra Road

San Antonio, TX 78238-5166

(210) 522-2574, fax: (210) 522-3270, e-mail: dnaegeli@swri.edu

DOE Program Manager: John Garbak

(202) 586-1723, fax: (202) 586-9811, e-mail: john.garbak@ee.doe.gov

Industry Co-Leads: Thomas Asmus (DaimlerChrysler) William Piel (Consultant)

This Project addresses the following OTT R&D Plan Barriers and Tasks:

Barriers

A. Fuel Property Effects on Engine Emissions and Efficiency

Tasks

2. Fuel and Lubricant Properties - Engine-Out Emissions

Objectives

• Assess the benefits and limitations of oxygenated diesel fuels on engine performance and emissions.

• Identify oxygenates for exhaust emissions and performance testing based on physicochemical 

properties, toxicity, biodegradability, and projected cost of production.

• Select at least two oxygenated compounds for advanced engine testing.

Approach

• Review the oxygenate literature to identify potential candidates.

• Select oxygenate candidates on the basis of:

- Oxygen content, flash point, solubility in low aromatic diesel fuel, and stability. 

- Fuel properties such as viscosity, cetane number, and lubricity.

- Elastomer compatibility.

- Results of a single mode emissions and performance test in a DaimlerChrysler OM611 CIDI 

engine.

- Potential toxicity, biodegradability, and air quality.

- Economics of producing the most technically promising oxygenates for diesel fuel.

• Based on the above criteria, two oxygenate candidates will be selected for multi-mode testing of 

engine performance and exhaust emissions in the 2.2L DaimlerChrysler OM611 CIDI engine.

Accomplishments

• A literature search on the effect of oxygenate compounds on particulate emissions from diesel engines 

was performed. 
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

16

• Seventy-one oxygenate candidates were screened on the basis of oxygen content, flash point, 

solubility in low aromatic diesel fuel, and stability. Six viable candidates emerged from the screening.

• Nine test fuels including an alternative low-sulfur diesel (ALS) reference fuel and eight oxygenateALS blends were tested for exhaust emissions and performance in a 2.2L DaimlerChrysler OM611 

CIDI engine. The tests were performed in triplicate at a single operating mode and the emissions 

measurements included Bosch smoke number, total PM, total volatile fraction, TVF, NOx, CO, CO2, 

O2, and total hydrocarbons.

• The test fuels were each prepared with 7 wt.% oxygen by adding the appropriate amount of oxygenate 

to ALS.

• Test fuel properties, including density, viscosity, surface tension, cetane number, boiling point 

distribution, and lubricity were measured by ASTM methods. Composition was determined using the 

carbon, hydrogen and oxygen contents of the ALS base fuel and oxygenate. 

• The compatibility of the oxygenated test fuels with elastomers was tested. Five O-rings, consisting of 

two Viton and three Nitrile type elastomers, were immersed in the ALS base fuel and eight oxygenated 

test fuels for 336 hours at 41o

C. Relative to the ALS base fuel, the oxygenated fuels caused significant 

degradation, especially in the Viton type elastomers.

• The following two oxygenates were recommended for additional research; tri-propylene glycol 

monomethyl ether and di-butyl maleate. 

Future Directions

• Determine the effect of oxygenates in diesel fuel on exhaust emissions when tested under the lightduty transient FTP cycle.

• Examine the effects of exhaust emission control devices on PM and NOx when using oxygenated 

diesel fuel. Since catalytic reactors are much more effective in reducing TVF than dry PM, 

oxygenated fuels are expected to reduce PM emissions even further because they tend to have a higher 

TVF than the PM from pure hydrocarbon fuels.

• Determine the effect of oxygenated fuels on particle size distribution.

• Evaluate the effect of oxygenates on potentially toxic polynuclear aromatics (PNAs) in particulate 

matter.

• Define the effect of oxygenate chemical structure on PM emissions.

Introduction

As the demand for energy rises, oil consumption 

will eventually outpace discovery. Unless 

infrastructures for alternative energy sources are 

developed in a timely manner, serious fuel shortages 

could result. To forestall a potential crisis and allow 

more time for a smoother transition to alternative 

energy sources, it is necessary to develop more 

efficient vehicles. The diesel engine is of particular 

interest because it is significantly more efficient than 

its spark ignited counterpart. However, more 

widespread use of diesel power sources is restricted 

by unacceptable exhaust emissions. Diesel engine 

manufacturers have made considerable progress in 

reducing harmful exhaust emissions. Combustion 

efficiency has been greatly improved through ultrahigh pressure fuel injection and better fluid flow. 

Electronic control has been used to optimize engine 

performance and lower exhaust emissions. However, 

the diesel engine has yet to meet the future emissions 

standards required by the EPA in the next decade.
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

17

A major problem is that particulate (smoke) 

emissions are still too high. Since further 

modifications to the engine design and operation 

alone will not reduce PM emissions to the required 

level, cleaner burning fuels and emission control 

devices are necessary. Future diesel fuels may have 

greatly reduced sulfur levels. Fuel sulfur has to be 

reduced because it degrades catalytic activity in 

emission control devices. Sulfur can be removed by 

hydrotreating, which also increases the hydrogen to 

carbon ratio, lowers aromatics, and raises cetane 

number. Low sulfur fuels also yield lower PM 

emissions because of the increased hydrogen to 

carbon ratio and the absence of sulfates, which would 

otherwise combine with soot to increase particulate 

mass.

Future reformulation of diesel fuel may involve 

addition of oxygenates. Several exhaust emissions 

studies have shown that using pure oxygenates such 

as methanol and dimethyl ether as diesel fuels 

essentially eliminate PM emissions. A number of 

other studies report that blending oxygenates into 

diesel fuel will also significantly reduce PM 

emissions in diesel exhaust. Figure 1 shows the 

effects of dimethoxymethane (DMM) and diethyl 

ether (DEE) blended with a CARB certified DF-2 on 

the PM and NOx emissions from a Cummins 5.9 liter 

turbodiesel. The results of Cheng and Dibble 

represent an average of nine operating modes. 

Figure 1 shows that the emissions benefit of blending 

oxygenates with diesel fuel goes beyond that 

explained by simple dilution. This disproportionate 

reduction in PM emissions is not observed when 

blending in a similar amount of low-PM hydrocarbon 

compounds. Several studies with results similar to 

that in Figure 1 show that it is primarily the added 

oxygen that suppresses the formation of soot or PM 

during combustion. However, there are claims in the 

literature that some oxygenates of different 

molecular structure are more effective in reducing 

PM emissions than others.

The impact and the limitations of oxygenates on 

the diesel combustion process have not been well 

defined. Questions on the importance of molecular 

structure and the maximum achievable PM reduction 

with oxygenate blends is difficult to quantify because 

the emissions data in the literature are from several 

engine types and different operating conditions. The 

purpose of the present study is to evaluate several 

oxygenates on an equal basis, i.e., establish criteria 

for the selection of oxygenates and then test them in 

the same engine under the same operating conditions.

Approach & Progress

Southwest Research Institute (SwRI) 

participated in an extensive industry-based review of 

published information and in-house but nonproprietary data. As part of the Oxygenate Analysis 

Project team which was comprised of representatives 

from the Ad-Hoc Fuels group (DOE, auto 

companies, and oil companies), SwRI organized the 

data for comparison and interpretation and for the 

development of correlations between the properties 

of oxygenated diesel fuel and PM emissions.

The literature search was comprised of two parts: 

1) to investigate the effect of oxygenates on PM 

emissions from engines; and 2) to gather data on the 

physicochemical properties of oxygenates. The 

engine studies showed that reductions in PM 

emissions correlated with oxygen content in the fuel. 

The studies indicated that an oxygen content of at 

least 7% in the fuel would be required to produce a 

50% reduction in PM. The literature was not clear on 

the effects of molecular structure on PM emissions.

Several oxygenate candidates were revealed in 

the literature search for the present study. The list of 

oxygenates finally grew to 71 as the members of the 

Figure 1. Effect of Oxygen Content on the Relative PM 

and NOx Emissions from DMM and DEE 

Diesel Fuel Blends, Cheng and Dibble, SAE 

Paper 1999-01-3606
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

18

Oxygenate Analysis Project members proposed new 

compounds.

The initial criteria used to screen the viable 

oxygenate candidates were: 1) the amount of 

oxygenate added to diesel fuel to give 7 wt.% oxygen 

should not exceed 20 vol.%; 2) the flash point should 

not be less than 52o

C; 3) oxygenate should be soluble 

in low aromatic diesel fuel at temperatures down to 

6oC and should tolerate at least 1000 ppm of water; 

and 4) oxygenate must not decompose into corrosive 

products. The data for criteria 1 and 2 were obtained 

from the literature, while 3 and 4 were measured at 

SwRI. Solubility tests were performed by vigorously 

mixing 25 mL of oxygenate with 50 mL of diesel 

fuel and the allowing the mixture to stand. Fischer 

Tropsch diesel (FT) and Swedish Low-Sulfur diesel 

(SLS) were used as reference fuels. FT diesel was 

mostly composed of paraffins while SLS diesel 

contained a sizeable fraction of napthenes. Neither 

reference fuel contained more than 2 percent 

aromatics. Since aromatics in diesel fuel tend to 

increase the solubility of oxygenates, the FT and SLS 

diesels represented a worst case for solubility. 

Oxygenate solubility was measured in terms of the 

phase separation that occurred. If there was no 

separation at room temperature, the test was 

performed at 6o

C. If the mixture passed the low 

temperature test, 1000 ppm of water was added and 

the test was repeated.

Stability was measured using the NACE D 665 

corrosion test. Oxygenates were blended with SLS 

diesel in amounts required to achieve an oxygen 

content of 7 weight percent in the blend. The D 665 

test measures the degree of corrosion that develops 

on a steel spindle immersed in a mixture of 30 mL of 

water and 300 mL of the oxygenate-SLS diesel 

blend. The mixture is stirred and held at 60o

C for 

four hours after which the spindle is removed and 

Oxygenate-ALS Diesel 

Blend

Oxygenate 

Vol. %

NACE 

Corrosion

Cetane 

Number

Density, 

g/cm3

Viscosity, 

cSt

Surface 

Tension

Lubricity, 

microns

ALS-Base Reference 

Fuel 0 Passed 65.5 0.8169 2.94 30.3 483

Methylal (DMM) 16.06 NA 62.9 0.8217 1.67 28.4 503

Oxygenate-ALS Blends to be Tested in 2.2 L OM611 Engine

Di-butyl maleate--ALS 21.64 Pass-B 57.7 0.8537 2.78 31.1 268

Tributyrin--ALS 18.35 Pass-B 52.6 0.8550 3.06 30.6 375

Di-ethyl adipate--ALS 18.76 Passed 56.0 0.8506 2.55 30.9 443

2-ethoxy ethyl acetate--

ALS 16.72 Pass-A 61.3 0.8397 2.10 31.0 490

2-ethoxy ethyl ether--

ALS 21.85 Passed 86.4 0.8342 2.09 31.0 670

Tripropylene glycol 

monomethyl ether--ALS 19.80 Pass-B 65.0 0.8416 2.73 30.5 505

Dipropylene glycol 

monomethyl ether--ALS 19.42 Pass-B 61.4 0.8403 2.54 30.4 545

1-methoxy-2-propanol--

ALS 17.92 Passed 57.2 0.8321 2.19 30.8 495

Other Candidates

2-Butoxy ethanol--ALS 24.05 Pass-B 59.6 0.8354 2.50 30.4 395

2,4,7,9-tetra-oxa-decane 

(TOD)--ALS 13.82 Pass-A 64.5 0.8402 2.24 30.5 623

NA = No Analysis

ALS = Alternative Low Sulfur Diesel Fuel

NACE Corrosion Test is the ASTM D 665 test.

 Passed = No visible corrosion on the steel spindle

 Pass-A = Light corrosion (fewer than 6 rust spots)

 Pass-B = Medium corrosion (less than 50% coverage of spindle with rust spots)

Table 1. Properties of Oxygenate-ALS Diesel Fuels Blended to 7 Percent Oxygen
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

19

inspected for corrosion. If there are fewer than six 

rust spots, the fuel is given an A-rating. If less than 

50 percent of the spindle surface has rust spots, a Brating is given, and if more than 50 percent is rusted, 

a C-rating is given. Normally, A, B, and C ratings 

are failures, but since only a few of the oxygenateDF2 blends passed the test with no rust spots, the test 

had to be scored more leniently. Ratings of A and B 

passed, whereas C failed.

Of the 71 oxygenate candidates screened, 28 had 

flash points too low. Oxygen contents were too low 

in three of the remaining 43, and 23 of the remaining 

40 were insoluble in low-aromatic sulfur-free diesel 

fuel. One oxygenate had an unbearable odor, and of 

the sixteen remaining, seven failed the D 665 

corrosion test, leaving nine eligible for engine 

testing.

The eight oxygenate compounds eligible for 

engine testing were blended with alternative low 

sulfur diesel fuel, ALS, in the amounts required to 

achieve an oxygen content of 7 wt.%. The density, 

viscosity, surface tension, flash point, heat of 

combustion, boiling point distribution, cetane 

number, and lubricity of each oxygenate-ALS blend 

were measured.

Table 1 shows the properties of the oxygenateALS blends considered for engine testing. Nine test 

fuels were selected for exhaust emissions and 

performance testing at one operating mode in the 

2.2L DaimlerChrysler OM611 CIDI engine. They 

include the ALS base fuel and the eight oxygenateALS blends shown in Table 1.

The last three oxygenate-ALS blends selected for 

engine testing in Table 1 comprise a homologous 

series of mono-, di-, and tri-propylene glycol monomethyl ethers. The propylene glycol mono-methyl 

ethers were included in the test matrix to determine 

the effect of oxygenate volatility on PM emissions. 

Oxygenates selected for the engine test contained 

ether, ester, and alcohol groups.

Emissions tests were performed in triplicate at 

Mode 6 (2,300 rpm and 4.2 bar BMEP). EGR was 

set at 15 percent and the location of peak pressure 

was adjusted to 7o

 ATDC. The Bosch smoke number, 

total PM, total volatile fraction (TVF), NOx, CO, 

THC, CO2, and O2 were measured. Dry PM, which 

is assumed to form during the combustion process, 

was calculated by subtracting the TVF from the total 

PM.

Table 2 summarizes the results of the present 

study, and Figure 2 shows the effect of oxygenated 

fuels on TVF, dry PM, and total PM. The fuel labels 

in Figure 2 are defined in Table 2. The PM emissions 

from the oxygenate fuels were substantially lower 

than the reference Fuel A. It is seen that the total PM 

emissions from the oxygenate-ALS blends are 

Proposed 

Ranking 

& Label

Oxygenate-ALS 

Blend

Relative Emissions Added 

Cost, 

cents/

gal

Predicted 

Biodegradability 

Relative to 

Benzene

Elastomer 

Compatibility 

Ranking

T90, o

C Oxygen 

Vol %

Flash 

Point, 

o

C

Total 

PM

Dry 

PM NOx Toxicity

9-A ALSD Base Fuel 

for reference 100 100 100 LR 0 NA 1 346 0 88

8-D

Dipropylene 

glycol 

monomethyl ether

75 62 96 LR 30 NR NR 342 19 77

7-C 1-methoxy-2-

propanol 70 43 112 LR 27 NR 6 343 18 35

6-E 2-ethoxy ethyl 

acetate 75 67 95 SC 26 1.25 7 344 17 62

5-G Diethyl adipate 74 62 111 SC 76 1.35 8 340 19 91

4-F 2-ethoxy ethyl 

ether 75 68 106 LR 43 0.73 3 342 22 78

3-H Tributyrin 78 56 111 LR 29 1.36 4 342 18 91

2-I Dibutyl maleate 74 56 119 SC 33 1.33 5 340 22 93

1-B

Tripropylene 

glycol 

monomethyl ether

70 52 113 LR 30 0.21 2 342 20 90

LR = lower risk based on limited data; SC = some concern; NA= no analysis; NR = no result; U = unknown

Table 2. Fuel Property Analysis and Engine Emissions Measurements
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

20

essentially equal, while there are distinct differences 

in the TVF and dry PM emissions. It is also seen that 

the TVF of the oxygenated fuels is larger than that of 

the neat ALS reference fuel. The variations in the 

dry PM suggest that oxygenate composition and 

structure have some effect on PM emissions. 

Additional research is needed to define the effect of 

oxygenate structure on PM emissions. It is also 

interesting to note that the relatively high TVF of the 

oxygenated fuels may enhance the completeness of 

oxidation in catalytic emission control devices.

Other factors important in choosing appropriate 

oxygenate compounds for use in diesel fuel include 

the economics of production, toxicity, and 

biodegradability. Cost was estimated assuming that 

oxygenates would be made on a scale appropriate for 

the fuels industry. The estimates (added fuel cost) 

given in Table 2 were based on the cost and 

availability of raw materials and production 

efficiency. Toxicity was given special emphasis in 

the study. The results given in Table 2 are based on 

literature data. The relative times for 

biodegradability given in Table 2 were estimated 

using a model developed at Lawrence Livermore 

Laboratories.

According to the data in Table 2, the test fuels are 

ranked from 1 to 9, with 1 being the highest rating. 

The two oxygenates given the highest rating are 

tripropylene glycol monomethyl ether and dibutyl 

maleate.

Conclusions

Emissions and performance tests have been 

completed on eight oxygenated diesel fuels at one 

operating mode in a 2.2L DaimlerChrysler CIDI 

engine. The data have been analyzed and the 

following two oxygenates were recommended for 

additional research: tripropylene glycol monomethyl 

ether and dibutyl maleate. The final report is in 

progress.

List of Presentations

1. Naegeli, D.W.m, Moulton, D.S., Childress, K.H., 

and Yost, D.M., "Oxygenate Analysis Project", 

presented at the Transportation Panel Meeting, 

held May 11, 2000 in Troy, Michigan.

2. Naegeli, D.W., Moulton, D.S., Childress, K.H., 

and Yost, D.M., "Oxygenate Analysis Project," 

Presented at the CIDI Engine Combustion, 

Emissions Control, and Fuels R&D Laboratory 

Merit Review & Peer Evaluation, held May 22-

24, 2000 at Argonne National Laboratories.

List of Acronyms

ALS Alternative Low-Sulfur Diesel Fuel

ASTM American Society for Testing and 

Materials

ATDC After top dead center

BMEP Brake mean effective pressure

CIDI Compression-Ignition Direct 

Injection

CO Carbon Monoxide

CO2 Carbon Dioxide

DEE Diethyl ether

DMM Dimethoxymethane

FTP Federal Test Procedure

NOx Oxides of Nitrogen

O2 Oxygen

PM Particulate Matter

PNA Polynuclear aromatic

SLS Swedish low-sulfur diesel fuel

SwRI Southwest Research Institute

THC Total Hydrocarbons

TVF Total Volatile Fraction

Figure 2. Effect of Oxygenates on the Dry and Volatile 

Matter Fractions of the Total PM (Oxygenates 

are identified in Table 2)
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

21

C. Production of Transportation Fuel from C1 Chemistry

Gerald P. Huffman, Director

CFFLS

533 South Limestone Street

111 Whalen Building

University of Kentucky

Lexington, KY 40506-0043

(859) 257-4027, fax: (859) 257-7215, e-mail: cffls@pop.uky.edu 

DOE Program Manager: Peter Devlin

(202) 586-4905, fax: (202) 586-9811, e-mail: Peter.Devlin@ee.doe.gov

DOE Program Manager: Richard Noceti

(412) 378-5955, fax: (412) 386-6216, e-mail: noceti@netl.doe.gov 

Contractor: University of Kentucky, Lexington, KY

Subcontractors: Auburn University, Auburn, AL; University of Pittsburgh, Pittsburgh, PA; University 

of Utah, Salt Lake City, UT; West Virginia University, Morgantown, WV

This Project addresses the following OTT R&D Plan Barriers and Tasks:

Barriers

G. Advanced Fuel Production and Cost

Tasks

5. Refinery and Fuel Processing Economics

Objectives

• Develop technology for conversion of C1 source materials (natural gas, synthesis gas, carbon dioxide 

and monoxide, and methanol) into clean, high efficiency transportation fuel, especially diesel fuel. 

• Develop improved processes to convert natural gas into syngas.

• Develop new processes for producing hydrogen from natural gas and other hydrocarbons.

Approach

• Faculty and students from five universities (Kentucky, West Virginia, Utah, Pittsburgh, and Auburn) 

are collaborating on a basic research program to develop novel C1 chemistry processes for the 

production of clean, high-quality transportation fuel. An Industrial Advisory Board (IAB) with 

members from Chevron, Eastman Chemical, Teir Associates, DaimlerChrysler, Energy International, 

and the Department of Defense has been formed to provide practical guidance to the program.

Accomplishments

• Fischer-Tropsch fuels containing oxygen have been synthesized.

• Higher ethers (C6-C8) have been synthesized from olefins, methanol and ethanol.

• Dimethyl and diethyl carbonates have been produced from the reaction of methanol and carbon 

monoxide.
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

22

• A small diesel engine has been set up to test the effects of these fuels, either alone or as additives, on 

particulate matter emissions and cetane level.

• Nanoscale, binary, Fe-based catalysts have been shown to have significant catalytic activity for the 

decomposition of methane to produce pure hydrogen.

• Work on CO2 reforming of methane to synthesis gas has been initiated.

• In situ analytical capability has been developed to allow determination of catalyst structures and 

product suites during C1 reactions.

Future Directions

• All current research projects will continue with continuing evolvement based on guidance from the 

IAB and DOE.

Introduction

Since 1986, the Consortium for Fossil Fuel 

Liquefaction Science (CFFLS) has been engaged in 

research on the development of alternative sources 

for transportation fuel. Currently, the CFFLS 

research program is focused on C1 chemistry, which 

refers to the conversion of feed stocks that have one 

carbon atom per molecule (natural gas, synthesis gas, 

carbon dioxide and monoxide, and methanol) into 

clean, high efficiency transportation fuel. Synthesis 

gas, or syngas, is a mixture of CO and H2 that can be 

produced by reforming of natural gas or gasification 

of coal, biomass, petroleum coke, and waste 

materials. Syngas is the principal source material for 

the production of hydrogen, methanol, FischerTropsch products and many chemicals. Because of 

the abundance of remote natural gas, the advent of 

integrated gasification combined cycle (IGCC) 

power generation, and environmental advantages, 

syngas availability and industrial interest in C1 

chemistry are expected to grow rapidly. The CFFLS 

will therefore perform a valuable national service by 

providing science and engineering graduates trained 

in this important area. 

A major goal of the CFFLS C1 program is to 

develop technology for producing high quality 

oxygenated transportation fuels and fuel additives 

from methanol and syngas. There is abundant 

evidence that oxygenates both increase fuel 

efficiency (cetane and octane levels) and decrease 

particulate emissions. The development of novel 

methods for producing H2, perhaps the ultimate 

transportation fuel of the future, is also an important 

part of the program. Research is also underway on 

development of new catalysts for conversion of 

natural gas into syngas by reforming with carbon 

dioxide. This report briefly summarizes some of the 

research highlights of the first year of the program. 

Catalytic synthesis of organic carbonates

The catalytic synthesis of diethyl carbonate 

(DEC) and dimethyl carbonate (DMC)(1) is being 

investigated. Both compounds may be used as 

additives to diesel fuel to reduce particulate 

emissions and increase cetane levels. Members of 

our Industrial Advisory Board have pointed out that 

DEC is a more promising additive because it has 

lower volatility and water solubility than DMC. 

Consequently, only the results of the DEC study are 

discussed here.

Figure 1. Effect of pretreatment of the catalysts with 

various metal hydroxides on the yields of DEC, 

acetaldehyde, ethyl formate, and unidentified 

species
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

23

The equation describing the desired reaction is:

 The best yields of DEC have been obtained with 

a CuCl2/PdCl2 on activated carbon catalyst. The 

yield and selectivity is significantly improved by 

metal hydroxide pretreatment of the catalyst, with the 

best results provided by Ba(OH)2 (Figure 1).

Synthesis of higher ethers

With the banning of MTBE in California, there is 

considerable interest in finding suitable oxygenate 

substitutes. This project is focused on kinetics, 

reaction conditions and new catalysts for the 

production of higher ethers that are much less 

volatile and water-soluble. We have investigated 

synthesis of a C7 ether, 2,3 dimethyl-2-

methoxybutane (DM2MB), from dimethyl butenes 

and methanol, and of other higher ethers from this 

olefin and butanol, propanol and ethanol as well as 

binary mixtures of these alcohols. Reactions were 

performed using the commercial catalyst, Amberlyst15, and several new laboratory-prepared catalysts. 

Details of these studies are reported in two 

forthcoming publications.(2,3) Results obtained 

with a new catalyst, Zr(SO4)2 on sulfuric acid-treated 

SiO2, are shown in Figure 2. The loading of Zr(SO4)2

in SZ/SiO2(H2SO4) greatly influences the catalytic 

activity and selectivity. Both 2,3-dimethyl-1-butene 

(23DM1B) and 2,3-dimethyl-2-butene (23DM2B) 

conversion and ether selectivity generally increase as 

the Zr(SO4)2 loading increases. Ether yield saturates 

at ~30% when the wt% Zr(SO4)2 exceeds 50%. A 

catalyst calcination temperature of 600o

C has been 

found to produce the highest ether yield.

Oxygenated Fischer-Tropsch Derived Diesel 

Fuel

This project aims to convert synthesis gas to F-T 

products from which environmentally clean diesel 

fuels containing 4-10 wt% oxygen in the 

hydrocarbon chain can be produced. The resulting FT diesel fuel should have a high cetane number and 

be effective in reducing particulate matter emissions. 

An automated high pressure, fixed bed, continuous 

F-T unit has been constructed and is now operational. 

Temperatures, flow rates and sampling times are 

controlled and recorded by computer. The products 

are analyzed using three GC columns and a GC/MS. 

A Visual Basic program was written to integrate the 

data and calculate the conversions and product 

distributions. 

A Ru-promoted Co/Al2O3 catalyst was prepared 

by incipient wetness impregnation procedures. The 

resulting catalyst consisted of 20% Co and 0.5 wt% 

Ru on γ-Al2O3. Oxygenates (primarily alcohols) 

were obtained when the F-T reaction was conducted 

at lower temperatures (190-200o

C). Product 

distributions of the collected oil fraction of the F-T 

product are shown in Figure 3. The amounts of 

oxygenates, olefins and paraffins are 10.2%, 26.5% 

and 63.3% respectively.

Figure 2. Effect of Zr(SO4)2 content in SZ/SiO2(H2SO4) 

system on catalytic activity

Figure 3. Product distribution of the F-T oil fraction
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

24

Methane Reforming with Carbon Dioxide

The reforming of natural gas with carbon dioxide 

for the production of synthesis gas is appealing 

because: (1) it produces synthesis gas with higher 

purity and lower H2/CO ratio than either partial 

oxidation or steam reforming, which is desirable for 

the production of transportation fuels; (2) two 

greenhouse gases are utilized; and (3) CO2 is 

frequently a significant component of natural gas and 

is produced in many industrial processes. Initial 

studies have focused on calibration and testing of the 

reforming unit, which features four independently 

controlled gas feed lines and on-line analysis of the 

products using a Hewlett-Packard 5890 gas 

chromatograph. Tests run using a commercial Ni/

Al2O3 catalyst have shown the expected dependence 

of the % CH4 and % CO2 conversions on reaction 

temperature. Future studies will focus on transition 

metal carbide catalysts.

Catalytic methane decomposition

The goal of this project is to develop catalysts 

and reaction conditions for catalytic, non-oxidative 

decomposition of hydrocarbons. The advantage of 

this approach is that it produces hydrogen that is free 

of CO, which poisons the catalysts used in fuel cells. 

It has been demonstrated that nanoscale, binary 

ferrihydrite catalysts are readily formed by coprecipitation techniques.(4,5) In the current 

research, nanoscale iron-based catalysts are being 

precipitated on alumina supports and subjected to 

various pre-treatments to put them into metallic, 

carbide, or oxide form prior to reaction. Some 

typical results for methane decomposition are shown 

in Figure 4 for several catalysts that were pre-treated 

by reduction at 1000o

C. It is seen that both the 5% 

Fe/Al2O3 and the 0.5%Mo-4.5%Fe/Al2O3 catalysts 

reduce the methane decomposition temperatures by 

over 300o

C, while the 5%Mo/Al2O3 catalyst gives 

results that are similar to the alumina support alone. 

Further experiments using a variety of pre-treatments 

and numerous other secondary elements (Pd, Ir, W, 

V, etc.) are in progress. Liquid hydrocarbons will 

also be investigated in future work.

Hydroisomerization of Normal Hexadecane 

with Pt/WO3/ ZrO2 Catalysts

The acid-catalyzed isomerization of alkanes is 

used to produce clean, high octane gasoline, high 

cetane diesel fuel, low pour point jet fuel and 

lubricant base stocks. This work has established that 

platinum-promoted tungstate-modified zirconia (Pt/

WO3/ZrO2) catalysts are very effective for the 

hydroisomerization of long-chain linear alkanes 

under relatively mild conditions, using n-hexadecane 

(C16) as a model compound. Research has now 

shifted to the hydroisomerization and hydrocracking 

of longer paraffinic chains; C24, C28 and C32, as well 

as to the conversion of Fischer-Tropsch waxes to 

high cetane diesel and jet fuels.

Carbon Dioxide as an Oxidizing (Dehydrogenating) Agent

Utilization of CO2 in the dehydrogenation of 

hydrocarbons could be used to produce chemicals 

efficiently and, at the same time, convert this 

greenhouse gas to valuable CO gas. Styrene, a high 

volume, high value chemical, is produced by 

dehydrogenation of ethylbenzene in the presence of 

steam and a catalyst. 

Dehydrogenation of ethylbenzene could involve 

the following reactions:

CO could be produced either by reaction (1) or 

by a combination of reactions (2) and (3). We have 

Figure 4. Catalytic CH4 cracking-effect of catalyst-5% 

Fe/Al2O3, 0.5% Mo/4.5% FeAl2O3 and 5% Mo/

Al2O3-reduced in hydrogen at 1000oC for 2 

hours
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

25

identified several catalysts that are effective for these 

reactions, including Fe/Al2O3, Pt/WO3/ZrO2, and Fe/

activated carbon.

Analytical Research

A pulse-quench reactor has been constructed that 

can quench catalyst beds during C1 reactions from 

450o

C to room temperature in less than 1 second, in 

order to investigate reactive species on the catalyst 

surface by solid-state NMR. 

A portable AVS-GC/MS (AVS - ambient vapor 

sampling) system has been developed for real-time 

monitoring of the volatile reaction products from C1 

reactions. 

An in situ cell for x-ray absorption fine structure 

(XAFS) spectroscopy analysis of catalyst structure 

during C1 reactions at temperatures up to 700o

C has 

been designed. It will be tested at the National 

Synchrotron Light Source (NSLS) later this year. 

A small diesel engine is being set up that will be 

equipped with a battery of engine performance and 

emissions monitoring devices. Among the latter are: 

NOx, CO, SOx, VOC/SVOC (on-line GC/MS), and 

particulate matter characterization and collection. 

This engine will enable us to perform realistic tests 

on the small quantities of diesel fuel produced in our 

bench scale laboratory experiments.

Significant progress has been made in relating 

the magnetic properties of a number of catalysts 

under investigation to their activities in C1 

reactions.(6-8) 

Conclusions

Collaborating faculty and students at five 

universities have made excellent progress on C1 

chemistry research projects focused on the 

development of new synthesis processes for 

transportation fuel. The products emphasized 

include oxygenated diesel fuel and fuel additives, 

and hydrogen. An annual report of research 

conducted during the first year of the program is 

available at the CFFLS web page, http://

www.cffls.uky.edu.

List of References

1. B.C. Dunn, J. Pahnke, D. Hopkinson, E.M. 

Eyring, G. Deng, J. Dworzanski, H. L. C. 

Meuzelaar, R. J. Pugmire, Am. Chem. Soc., Div. 

Fuel Chem. Preprints, 45 (2), 283-287 (2000).

2. Liu, J., Wang S., Guin, J. A., Fuel Processing 

Technology, submitted.

3. Wang S., Liu, J., and Guin, J. A., J. Catal., 

submitted.

4. Jianmin Zhao, Zhen Feng, F.E. Huggins, and 

G.P. Huffman, Energy & Fuels, 1994, 8, 38-43.

5. G.P. Huffman, J. Zhao and Z. Feng, "Binary 

Ferrihydrite Catalysts,", U.S. Patent Number 

5,580,839, Dec.3, 1996.

6. A. Punnoose, M. S. Seehra and I. Wender, J. 

Catal., submitted.

7. M. S. Seehra, V. S. Babu, P. Roy and A. 

Manivannan, Cluster and Nanostructure 

Interfaces , World Scientific, June 2000 (in 

press).

8. P. Roy, A. Manivannan and M. S. Seehra, Phys. 

Rev. B, submitted.

List of Acronyms

23DM1B 2,3-dimethyl-1-butene

23DM2B 2,3-dimethyl-2-butene

AVS-GC/MS Ambient vapor sampling gas 

chromatograph/mass spectrometer

CFFLS Consortium for Fossil Fuel 

Liquefaction Science

DEC Diethyl Carbonate

DM2MB 2,3-dimethyl-2-methoxybutate

DMC Dimethyl Carbonate

F-T Fischer-Tropsch Diesel

IAB Industrial Advisory Board

IGCC Integrated Gasification Combined 

Cycle

MTBE Methyl Tertiary Butyl Ether

NSLS National Synchrotron Light Source

XAFS X-Ray Absorption Fine Structure
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

26

D. Modeling of Soot and NOx Formation from Combustion of Oxygenated Fuels 

in CIDI Engines

Charles K. Westbrook (primary contact), William J. Pitz

Lawrence Livermore National Laboratory

Livermore, CA 94550

(925) 422-4108, fax: (925) 422-2644, e-mail: westbrook1@llnl.gov

DOE Program Manager: John Garbak

(202) 586-1723, fax: (202) 586-9811, e-mail: john.garbak@ee.doe.gov

This Project addresses the following OTT R&D Plan Barriers and Tasks:

Barriers

A. Fuel Property Effects on Engine Emissions and Efficiency

Tasks

4. Develop Empirical Relationships

Objectives

• Use detailed kinetic modeling of hydrocarbon combustion to understand the chemistry of soot and 

NOx formation in diesel combustion.

• Examine impacts of oxygenated hydrocarbon additives on diesel soot production, using kinetic 

models.

• Develop and apply kinetic models for selected biodiesel fuels to determine sooting tendencies.

• Use model results to screen possible oxygenated diesel fuels and select those to be studied 

experimentally.

• Develop reduced kinetic models for incorporation into 3D CFD models of engine combustion.

Approach

• Develop kinetic models for specific hydrocarbon and oxygenated hydrocarbon fuels.

• Establish baseline model simulations of soot precursor production during diesel ignition and NOx

formation during diffusion flame combustion.

• Repeat baseline combustion model calculations with modified fuels and fuel/additive mixtures to 

estimate sooting and NOx trends.

• Propose and test reduced submodels for sooting and NOx production in CFD models of diesel 

combustion.

Accomplishments

• Established the connection between fuel-rich premixed ignition products and formation of soot 

precursors in diesel combustion.

• Developed and validated kinetic models for dimethyl ether, dimethoxy methane, ethanol, methanol, 

methyl formate, and methyl butanoate.

• Used mixtures of n-heptane as diesel fuel surrogates with selected oxygenated alternative fuel 

additives to predict reductions in soot precursor production.
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

27

• Established minimum NOx levels for diesel combustion conditions.

Future Directions

• Develop and test reduced models for soot and NOx production in diesel engine combustion.

• Extend kinetic models to new oxygenated alternative diesel fuels, and test their effectiveness in soot 

precursor production.

• Use models to identify potentially effective new additives.

Introduction

Experimental studies have indicated that use of 

oxygenated hydrocarbon fuels in conventional diesel 

engines can reduce soot production and emissions of 

oxides of nitrogen (NOx). However, it is not clear 

why these reductions occur, or whether or not they 

are a feature of all oxygenated fuels. 

Kinetic modeling capabilities at LLNL have 

been shown to be able to describe the mechanisms of 

soot precursor production in conventional diesel 

combustion, as well as the chemistry of NOx

formation in engine systems. In addition, current 

kinetic modeling is able to establish reliable models 

for proposed oxygenated fuels as needed. The goal 

of the present project is to use this diesel combustion 

modeling capability to examine the role of 

oxygenated fuel components in reducing soot 

production and NOx emissions from diesel engines.

Approach

Fuel-rich, premixed diesel fuel ignition 

calculations are carried out to simulate the creation 

of soot precursors at elevated pressures characteristic 

of diesel combustion. Soot precursors are identified 

as hydrocarbon species that are known to be 

particularly effective at producing aromatic 

hydrocarbon species growth, processes which 

encourage soot production, and the concentrations of 

these species in the rich ignition products are 

correlated with sooting tendency. A baseline level of 

these soot precursors are determined using n-heptane 

as a non-oxygenated fuel that is typical of 

conventional diesel fuel.

Selected oxygenated species are then substituted 

for portions of the n-heptane fuel, ranging from very 

small amounts of the oxygenated additive to 

completely oxygenated fuels, and for each ignition 

calculation, the total concentrations of the soot 

precursor species are determined. The same 

Figure 1. Experimental soot emissions from diesel 

engines with mixtures of diesel fuel and 

oxygenated additives. Results taken from 

Miyamoto et al., SAE-980506.

Figure 2. Computed soot precursor concentrations using 

kinetic models, using n-heptane as the diesel 

fuel, with a variety of oxygenated additives, as 

noted.
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

28

modeling calculations are repeated for a wide range 

of different oxygenated species. For many of these 

oxygenates, new kinetic reaction mechanisms must 

be developed, using data of many types, such as the 

different bond energies shown in Figure 1. In this 

manner, the variation in concentrations of proposed 

soot precursors with the type of oxygenated additive 

and with the relative concentration of the oxygenate 

in the diesel fuel can be determined.

Results

The oxygenated species used in this numerical 

modeling study included methanol, ethanol, dimethyl 

ether, methexoy methane, and a sample biodiesel 

fuel. For every oxygenated fuel component, the soot 

precursor concentrations decreased steadily as the 

fraction of the additive was increased in the nheptane diesel fuel. These results are summarized in 

Figure 2 as functions of the oxygen fraction in the 

fuel. The level of the precursors became close to 

zero at about 30% oxygen in the fuel, in good 

agreement with the experimental results from the 

literature. Furthermore, all of the results showed 

approximately the same dependence on oxygen 

additive concentrations in the fuel. 

Close investigation of the computed results 

indicated that the most important factor in these 

kinetic processes was the fact that all oxygen atoms 

in these fuels were bonded to C atoms. During the 

combustion, these C - O bonds were not broken by 

elementary reactions, remaining intact all the way 

until emerging as reaction products. As a result, 

those C atoms were not ever converted into the types 

of hydrocarbon fragments that contribute to soot 

production reactions, thereby lowering the levels of 

species which lead to sooting. 

The next steps in this program will be the study 

of further oxygenated additive species identified by 

the project leadership and industry representatives. 

The same type of analysis will be carried out. In 

addition, kinetic models with reduced complexity 

will be derived to make it possible to include sooting 

submodels into existing CFD codes.

Conclusions

This modeling work has established the primary 

factors influencing the role that fuel oxygen plays in 

reducing soot production in diesel engines. Kinetic 

models for many oxygenated fuels have been 

developed, and prototype fuels for other classes of 

oxygenated additives, particularly biodiesel fuels, 

have been identified. A computational basis for 

screening new oxygenated and other proposed diesel 

fuels has been tested and validated. This approach 

will be extended in the coming year to other 

important diesel fuel issues, including fuel sulfur, 

other oxygenated additives, and the development of 

reduced kinetic models for use in CFD models.

List of References

1. Flynn, P.F., Durrett, R.P., Hunter, G.L., zur Loye, 

A.O., Akinyemi, O.C., Dec, J.E., and Westbrook, 

C.K. "Diesel Combustion: An Integrated View 

Combining Laser Diagnostics, Chemical 

Kinetics, and Empirical Validation", Society of 

Automotive Engineers paper SAE-1999-01-0509 

(1999).

2. Flynn, P. F., Hunter, G. L., Farrell, L. A., Durrett, 

R. P., Akinyemi, O. C., zur Loye, A. O., C. K. 

Westbrook and W. J. Pitz, "The Inevitability of 

Engine-Out NOx Emissions from Spark-Ignition 

and Diesel Engines", Twenty-Eighth Symposium 

(International) on Combustion, in press (2000).

3. Fisher, E. M., Pitz, W. J., Curran, H. J., and 

Westbrook, C. K., "Detailed Chemical Kinetic 

Mechanisms for Combustion of Oxygenated 

Fuels", Twenty-Eighth Symposium 

(International) on Combustion, in press (2000).

4. Kaiser, E. W., Wallington, T. J., Hurley, M. D., 

Platz, J., Curran, H. J., Pitz, W. J., and 

Figure 3. Bond energies in methyl butanoate, a surrogate 

biodiesel fuel. Values are in kcal/mole.
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

29

Westbrook, C. K., "Experimental and Modeling 

Study of Premixed Atmospheric-Pressure 

Dimethyl Ether-Air Flames", J. Phys. Chem., 

accepted for publication (2000).

List of Acronyms

C carbon

CFD computational fluid dynamics

DBE di-n-butyl ether

DGM diethylene glycol mono-n-butyl 

ether

DME dimethyl ether

DMM dimethoxymethane

EHA ethylhexyl acetate

ENB ethylene glycol mono-n-butyl ether
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

30

E. In-Cylinder Imaging of Advanced Diesel Fuel Combustion in a CIDI Engine

Chuck Mueller (primary contact), Mark Musculus (post-doctoral research fellow)

Sandia National Laboratories

7011 East Avenue, MS 9053

Livermore, CA 94550-9517

(925) 294-2223, fax: (925) 294-1004, email: cjmuell@sandia.gov

DOE Program Manager: John Garbak

(202)586-1723, fax: (202) 586-9811, email: john.garbak@ee.doe.gov 

DOE Program Manager: Gurpreet Singh

(202) 586-2333, fax: (202) 586-1600, email: gurpreet.singh@ee.doe.gov

This Project addresses the following OTT R&D Plan Barriers and Tasks:

Barriers

A. Fuel Property Effects on Engine Emissions and Efficiency

Tasks

2. Fuel & Lubricant Properties - Engine-Out Emissions

Objectives

• Build and verify proper operation of a state-of-the-art, heavy-duty optical engine laboratory dedicated 

to the study of liquid-phase alternatives to conventional diesel fuel.

• Develop and apply laser-based and other imaging diagnostic techniques in the optical engine. Use 

results to advance the fundamental understanding of how fuel physical and chemical property 

variations affect in-cylinder combustion and emissions-formation processes.

• Feed back new knowledge to engine manufacturers, fuel suppliers, and other stakeholders so that 

engine design and fuel formulation can be used together in an optimal manner to meet future emissions 

and efficiency goals.

Approach

• Phase I: Construction and final assembly of Sandia/Caterpillar alternative fuels optical engine 

laboratory.

• Phase II: Initial shakedown/evaluation of engine performance, hardware infrastructure, and data 

acquisition systems.

• Phase III: Preliminary imaging study of glow plug assisted ignition and combustion of a low-cetane, 

highly-oxygenated alternative fuel. The fuel, M-85, was composed of 85% methanol and 15% 

gasoline.

• Phase IV: Detailed imaging study to characterize differences between combustion of M-85 and diesel 

reference fuel. Evaluation of potential of M-85 to reduce soot emissions.

• Phase V (ongoing): Periodically report results to partners in academia and industry through CIDI 

Oxygenates Screening Project and Alternative Fuels CRADA #1561.

Accomplishments

• All phases of the research listed above were completed.
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

31

• A world-class alternative fuels research facility was brought into operation.

• Direct flame luminosity, chemiluminescence, and Mie-scattering imaging techniques were 

demonstrated and used to gain insight into in-cylinder combustion processes.

• A new fuel injection strategy using slightly modified production Caterpillar equipment has been 

identified to enable the laboratory to most quickly recover from setbacks caused by the original 

injector platform.

Future Directions

• Quantify effects of fuel molecular structure and thermodynamic properties on soot formation using 

laser-induced incandescence (LII) and/or line-of-sight laser absorption diagnostics. Test fuels include 

blends of a low-sulfur base fuel with several particularly promising oxygenated molecules identified 

by the CIDI Oxygenates Screening Project [1].

• Study glow plug assisted combustion of neat methanol. Although methanol is not a practical near-term 

fuel for CI engines, its high oxygen content (50% oxygen by mass) and lack of carbon-carbon bonds 

make it an attractive fuel for studying the maximum soot reduction potential of an alternative fuel. 

These results also will establish a valuable experimental database for comparison to numerical 

simulations, since the chemical-kinetic oxidation mechanism of methanol is fairly simple and well 

understood.

Introduction

Existing experimental and modeling results 

indicate that advanced petroleum-based and 

alternative fuels can significantly reduce regulated 

pollutant and greenhouse gas emissions from dieselcycle engines. Fuels derived from domestic 

resources have the added benefit of enhancing U.S. 

energy security. However, many promising new 

fuels have physical and chemical properties that are 

vastly different from those of traditional diesel fuel. 

Gaining insight into how these property differences 

affect mixing, combustion, and emissions-formation 

processes inside the engine cylinder is the goal of 

this research. Such an improved understanding will 

help engine designers use new fuels to their greatest 

advantage, and could ultimately enable the 

identification of an optimal fuel blend for a given set 

of performance criteria.

Experimental Approach

The new Sandia alternative fuels optical engine 

laboratory features a single-cylinder version of a 

modern-technology, Caterpillar 4-stroke DI diesel 

engine that has been modified by Sandia to provide 

extensive optical access into the combustion 

chamber. The optical engine is based on the 

Caterpillar 3176/C-10 platform used in heavy-duty 

trucking. A photograph of the new laboratory is 

presented in Figure 1. A cutaway schematic of the 

optical engine is shown in Figure 2. The engine 

features a large window in the piston to image 

combustion processes, windows in the cylinder and 

piston bowl walls for laser access, and a glow plug to 

enable the study of certain low-cetane alternative 

fuels. Specifications of the optical engine are 

provided in Table 1. Fuel was injected using a preFigure 1. Sandia alternative fuels optical engine 

laboratory in operation
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

32

production prototype hydraulically-actuated, 

electronically-controlled unit injector (HEUI).

Results

Initial tests with Phillips #2 diesel reference fuel 

showed that the optical engine’s performance is 

representative of the production engine after which it 

is modeled. The motored gross IMEP, polytropic 

compression exponent, and heat release rates were all 

well within expected ranges. The tests also 

established that the extensive experimental 

infrastructure and all data acquisition systems were 

functioning properly. Traces of cylinder pressure and 

apparent heat release rate (AHRR) from the optical 

engine are shown in Figure 3.

The capability of operating with low-cetane 

alternative fuels was demonstrated by fueling the 

engine with M-85 and acquiring the sequence of 

direct flame luminosity (DFL) images, three frames 

of which are presented in Figure 4. The images, 

which were taken through the window in the piston 

with the glow plug on, show that M-85 ignition 

occurs at the glow plug, ignites the two fuel jets 

straddling the glow plug, and then the flame 

propagates to adjacent pairs of jets as it traverses the 

combustion chamber. The lack of luminous 

combustion on the side opposite the glow plug, 

coupled with lower-than-expected engine efficiency, 

suggests that fuel in this region may not completely 

burn. However, since the bulk of the DFL signal 

comes from the incandescence of hot soot, 

combustion in the region may be occurring, but in a 

Figure 2. Schematic diagram of the Sandia/Caterpillar 

optical engine

Production Engine Type 6-cylinder 3176 / C-10

Research Engine Type 1-cylinder version of 3176

Cycle 4 Stroke CIDI

No. Valves per Cylinder 4

Ignition Assist In-Cylinder Glow Plug

Bore 125 mm

Stroke 140 mm

Peak Cylinder Pressure 14.0 MPa

Connecting Rod Length 225 mm

Connecting Rod Offset None

Bowl Diameter 90 mm

Bowl Height 16.4 mm

Swirl Ratio Quiescent

Displacement 1.72 liters

Compression Ratio 1 11.3:1

Simulated Compression 

Ratio

16.0:1

1 TDC conditions of the production engine are matched to the 

optical engine by preheating and boosting the intake air

Table 1. Specifications of the Sandia/Caterpillar 

optical engine

Figure 3. Cylinder pressure and apparent heat 

release rate (AHRR) for the optical engine 

when fueled with #2 diesel reference fuel 

at a moderate load/1200 rpm operating 

condition.
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

33

non-sooting (and therefore non-luminous) premixed 

mode.

For comparison, Figure 5 shows three frames 

from a DFL image sequence at the same speed, load, 

and glow plug conditions as Figure 4, except that the 

engine was fueled with a 45-cetane diesel reference 

fuel mixture (CN45). It is clear from the images that 

the ignition and combustion processes of the CN45 

diesel fuel are markedly different from those of M85. Although the glow plug is energized, the CN45 

ignition occurs symmetrically on all jets at once. 

There is no jet-to-jet flame propagation process as 

was observed with M-85. In addition, the CN45 

images are more than 3 orders of magnitude brighter, 

as shown in Figure 6. Since the DFL signal is 

dominated by incandescence of hot soot, and the 

signal differences between the two fuels cannot be 

explained by differences in soot temperature, it is 

clear that the M-85 produces far less soot than the 

CN45 diesel fuel. Additional experiments were 

conducted using chemiluminescence and Miescattering diagnostics, at other speed/load operating 

conditions, and with the glow plug on vs. off [2].

Caterpillar provided two experimental, 

instrumented fuel injectors to Sandia for this project. 

Figure 7 shows a Mie scattering image of the 

exceptional spray symmetry produced by the 

injectors. Unfortunately, prolonged exposure to 

methanol caused the first injector to fail after the 

preliminary M-85 imaging study. Major mechanical 

problems that precluded further data acquisition with 

the second injector became apparent during the 

CN45 experiments. A large array of additional 

experiments (many of which touch on proprietary 

issues) were necessary to characterize the problems. 

It was found that the problems were caused by 

improperly tuned elements within the injector that 

could not be fixed by Sandia nor by Caterpillar. In 

hindsight, Caterpillar agrees that these "one-of-akind" experimental injectors should not have been 

provided to Sandia for use in research. Since 

production Caterpillar injectors do not exhibit such 

mechanical problems, a plan has been implemented 

Figure 4. Three frames from a movie of glow plug 

assisted combustion of M-85 acquired 

using DFL diagnostics. The central dot 

shows the injector location, the small 

circle the glow plug position, and the large 

circle the piston bowl wall. Conditions at 

TDC are 900 K and 60 bar. Injection 

timing is set for maximum indicated torque 

at 8.0 bar gross IMEP load and 1200 rpm.

Figure 5. Three frames from a DFL movie of glow 

plug assisted combustion of CN45 (a 

diesel reference fuel) for comparison to 

Figure 4. Ignition, combustion, and soot 

formation processes are drastically 

different between the two fuels (see also 

Figure 6). Engine operating conditions are 

the same as in Fig. 4.

Figure 6. Spatially-integrated DFL image signal as a 

function of crank angle for M-85 (circles) vs. 

CN45 (triangles) at the operating conditions of 

Figures 4 and 5. Since bulk of signal is 

produced by soot incandescence, more than 3 

orders of magnitude difference between the 

fuels indicates significant soot reduction 

potential of M-85.
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

34

that will enable the use of production injectors in the 

optical engine.

Conclusions

A new, state-of-the-art optical engine laboratory 

dedicated to the study of alternative fuels has been 

brought into operation. Experiments verify that the 

engine and laboratory are functioning properly. 

Images of glow plug assisted M-85 and CN45 

combustion are presented that show that ignition, 

combustion, and soot production processes are vastly 

different between the two fuels. Differences of these 

types must be understood for new CI fuels to be 

deployed with maximum emissions and efficiency 

benefits. The valuable capabilities that have been 

developed will be used in the next phases of the 

project to systematically identify fuel property 

effects on in-cylinder combustion and emissionsformation processes.

List of References

1. Naegeli, D., "Oxygenate Analysis Project," Proc. 

of CIDI Engine Combustion, Emission Control, 

and Fuels Program Review, May 22-24, 2000, 

Argonne National Laboratory, Argonne, IL.

2. Musculus, M.P., and Mueller, C.J., "Initial 

Results from Experiments on Alternative Fuels 

in the Sandia/Caterpillar Optical Engine," Sandia 

Report (in preparation), Sandia National 

Laboratories, Livermore, CA.

List of Publications

1. Mueller, C.J., "Recent Research Results on InCylinder Combustion Processes of Alternative 

Fuels for Diesel-Cycle Engines," Proc. of CIDI 

Engine Combustion, Emission Control, and 

Fuels Program Review, May 22-24, 2000, 

Argonne National Laboratory, Argonne, IL.

2. Musculus, M.P., and Mueller, C.J., "Initial 

Results from Experiments on Alternative Fuels 

in the Sandia/Caterpillar Optical Engine," Sandia 

Report (in preparation), Sandia National 

Laboratories, Livermore, CA.

List of Presentations

1. Mueller, C.J., "Alternative Fuels Research at 

Sandia National Laboratories," invited lecture, 

Sept. 14, 1999, Caterpillar Technical Center, 

Peoria, IL.

2. Mueller, C.J., "Glow Plug Assisted CI 

Combustion of M-85 in the Sandia/Caterpillar 

Optical Engine," Joint Heavy-Duty/Alternative 

Fuels Combustion CRADA Review Meeting, 

Oct. 12, 1999, US Council for Automotive 

Research, Detroit, MI.

3. Musculus, M.P., "Alternative Fuels Combustion 

in the Sandia/Caterpillar Optical Engine: 

Establishing the Baseline," Joint Heavy-Duty/

Alternative Fuels Combustion CRADA Review 

Meeting, Jan. 20, 2000, Sandia National 

Laboratories, Livermore, CA.

4. Mueller, C.J., "Biodiesel Research at Sandia 

National Laboratories: Capabilities and 

Results," Annual Biodiesel Research 

Coordination Meeting, Feb. 2, 2000, Phoenix, 

AZ.

5. Mueller, C.J., "Recent Experiments in the 

Sandia/Caterpillar Alternative Fuels Optical 

Engine," Dept. of Energy Mid-Year Program 

Review, March 16, 2000, Washington, DC 

(videoconference).

6. Musculus, M.P., "Overview and Results from 

Sandia Alternative Fuels Combustion Research," 

invited lecture, May 30, 2000, General Motors 

Technical Center, Warren, MI.

Figure 7. Mie-scattered light from droplets in CN45 fuel 

spray shows exceptional spray symmetry of 

Caterpillar injector. 
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

35

7. Mueller, C.J., "Status Report: Sandia Alternative 

Fuels Research Program," Joint Heavy-Duty/

Alternative Fuels Combustion CRADA Review 

Meeting, May 31, 2000, US Council for 

Automotive Research, Detroit, MI.

List of Acronyms

AHRR Apparent Heat Release Rate

CN45 Diesel reference fuel with cetane 

number = 45.0 by definition. 

Composition is 35.3 vol.% nhexadecane and 64.7 vol.% 

heptamethylnonane.

DFL Direct Flame Luminosity

HEUI Hydraulically-actuated, 

Electronically-controlled Unit 

Injector

IMEP Indicated Mean Effective Pressure

LII Laser-Induced Incandescence (of 

soot)

M-85 Fuel composed of 85% methanol 

and 15% gasoline.

TDC Top Dead Center
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

36

F. Impact of Consumed Lube Oil on Advanced CIDI Engine Emissions

Kent Froelund (primary contact), Ed C. Owens, Edwin A. Frame

Southwest Research Institute

6220 Culebra Road

San Antonio, TX 78238-5166

(210) 522-3664, fax: (210) 522-3270, e-mail: kfroelund@swri.edu

DOE Program Manager: John Garbak

(202) 586-1723, fax: (202) 586-9811, e-mail: john.garbak@ee.doe.gov

Industry Co-Leads: Andrew Jackson (ExxonMobil), Spyros Tseregounis (General Motors)

This Project addresses the following OTT R&D Plan Barriers and Tasks:

Barriers

A. Fuel Property Effects on Engine Emissions and Efficiency

Tasks

2. Fuel and Lubricant Properties - Engine-Out Emissions

Objective

• Determine the contribution of lube oil to particulate and to nitrogen oxide emissions measured in the 

exhaust gas stream of a state-of-the-art CIDI engine.

Approach

• A DaimlerChrysler OM611 CIDI engine was used to determine the effect of crankcase lube oil 

consumption on engine-out exhaust emissions (particulate matter [PM] and gaseous regulated 

emissions).

• Contribution of crankcase oil consumption to PM was determined by direct filter injection gas 

chromatography (DFI/GC) and by analysis of PM filter for concentration of lube oil additive metals.

• Three lubricant types were evaluated. One is conventional petroleum based and two are synthetic.

• Two fuels were included - one California type diesel fuel (CARB) and one low-sulfur fuel blend 

containing 15 volume percent dimethoxymethane (ADMM15).

• Measurements were conducted over 5 steady-state engine operation modes and over the heavy-duty 

diesel engine transient test procedure.

Accomplishments

• Project completed with delivery of draft report.

• Based on the DFI/GC technique and applying the CARB fuel, the oil-derived fraction of PM can be 

reduced from 27% for M5W30 oil to 8% for S15W50 oil for the important light-duty steady-state 

Mode 10. This indicates that a particulate matter reduction of approximately 19% is obtainable for this 

fuel and mode by changing the lubricant. It should be mentioned that this is a lower estimate for the 

oil impact on particulate at this operating condition since the oil might impact the fuel-VOF and nonVOF as well.

• Based on the DFI/GC technique, the highest oil impact to particulate measured was 36% (ADMM15 

fuel, M5W30 oil, and at steady-state Mode 10).
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

37

• Oil impacts nitrogen oxide emissions through its effect on friction characteristics.

• With this set of data, the impact of lubricant on the light-duty vehicle FTP exhaust emissions is 

inconclusive.

Future Directions

• Investigate the impact of consumed lube oil on vehicle emissions following the light-duty transient test 

cycle.

• Investigate the impact of ultra-low viscosity oils on exhaust emissions.

• Determine the oil impact on insoluble PM.

• Determine the impact of engine oil on polycyclic aromatic hydrocarbon emissions.

Objective

The purpose of this study was to determine the 

contribution of crankcase lube oil consumption to 

particulate and to nitrogen oxide emissions as 

measured in the exhaust gas stream of a state-of-theart CIDI engine. It was determined whether 

commercially available synthetic engine oil can 

significantly reduce the mass of the volatile organic 

fraction (VOF) of the particulate. In addition, 

measurements were made to determine whether 

changes in engine oil result in a change in nitrogen 

oxides or other gaseous regulated emissions.

Approach

Regulated gaseous and particulate emissions 

were collected from the exhaust gas stream of an 

unmodified DaimlerChrysler OM611 2.2-liter CIDI 

engine (Figure 1). The gaseous emissions were 

investigated by the means of a gaseous emission 

analyzer and the particulate emissions were 

characterized by taking two particulate filters from a 

particulate dilution tunnel. One of the particulate 

filters was analyzed by the direct filter injection gas 

chromatography (DFI/GC) method to determine the 

proportion of fuel and oil contribution to the VOF of 

the particulate. A second filter was analyzed by Xray fluorescence spectroscopy for oil additive metals 

in the PM.

These measurements were made with three 

different oils: one conventional petroleum-based 

product with an SAE viscosity grade of 5W30, one 

synthetic oil with an SAE viscosity grade of 5W30 

and one synthetic oil with an SAE viscosity grade of 

15W50. In addition, two fuels were used, one 

"CARB"-like fuel and one low-sulfur and lowaromatic fuel with 15 volume percent 

dimethoxymethane (DMM) added. Measurements 

were made over 5 steady-state test engine operation 

modes and over the heavy-duty diesel transient 

procedure. The modes chosen for this test program 

Figure 1. DaimlerChrysler OM611 Engine

Figure 2. Steady-State Test Modes
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

38

have been selected as a minimum set of operating 

modes that span the engine operating range and are 

presented in Figure 2. Transient engine operations 

have been shown to be significant contributors to 

both oil consumption and particulate emissions. 

While this engine is intended for light-duty vehicles, 

the light-duty FTP requires a total vehicle, and 

engine dynamometer simulations of this procedure 

are not standardized and are very sensitive to the 

assumed vehicle configuration. In order to examine 

transient operating effects, the engine dynamometer 

based heavy-duty FTP procedure was used.

These measurements may underestimate the total 

contribution of the engine oil to the particulate mass, 

since the DFI/GC technique only assesses the 

volatile portion of the particulate. For these 

conditions, the part of the PM that was non-volatile 

ranged from a low of 46% (ADMM15, M5W30, M5) 

to as much as 94% (CARB, S5W30, M14) of the 

total PM.

Results

• The steady-state results were arithmetically 

averaged to give an average steady-state mode. 

Confirming previous studies, fuel effect on 

particulate emissions is significant for the 

average steady-state condition (Figure 3). 

Applying ADMM15 fuel, particulate emissions 

decreased by 40-50% as compared to the 

baseline CARB fuel. 

• When grouping all the data for the fuels, the 

effect of oil on particulate emissions is 

insignificant for the average steady-state 

conditions (Figure 4). However, fractionating 

the particulate yields another interpretation. For 

Mode 10, which is typical of light-duty 

operations, the oil has substantial impact on 

Figure 3. Fuel Effect on Particulate for Average SteadyState Mode, Average across Lubricant Oils

Figure 4. Oil Effect on Particulate for Average SteadyState Mode, Average across Fuels

Figure 5. Fractionated Particulate Showing Fuel and Oil 

Contributions to PM (CARB Fuel; 5W30 

Baseline Mineral Oil)

Figure 6. Oil and Fuel Contribution to Particulate 

Emissions for the Fuel/Oil Combination 

Yielding the Highest Oil Contribution to PM 

(ADMM15 Fuel and 5W30 Baseline Mineral 

Oil)
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

39

particulates as shown in Figures 5, 6, and 7. 

With the CARB fuel and mineral 5W30 oil, the 

oil made up at least 27% of the total particulate 

mass at Mode 10 (Figure 5).

• With the low PM forming ADMM15 fuel, the 

mineral 5W30 oil contribution to PM increased 

to at least 36% at Mode 10 (Figure 6). 

• The lowest apparent contribution of oil to PM 

was with CARB fuel and synthetic 15W50 oil, 

which had at least 8% of the PM derived from 

the oil at Mode 10 (Figure 7).

• Oil effect on nitrogen oxides is significant for the 

average steady-state condition (Figure 8). The 

oil effect is correlated with friction 

characteristics of the oil, and applying the 

synthetic 15W50 oil, the nitrogen oxides 

increase 10-20% as compared to the 5W30 oils.

• Oil effect on carbon dioxide is significant for the 

average steady-state condition (Figure 9). The 

oil effect is correlated with friction 

characteristics of the oil, and applying the 

synthetic 15W50 oil, the carbon dioxide 

increases 5-10% as compared to the 5W30 oils.

Conclusions

• Based on the DFI-GC technique and applying the 

CARB fuel, the oil-VOF fraction can be reduced 

from 27% for M5W30 oil (Figure 5) to 8% for 

S15W50 oil (Figure 7) for the important lightduty steady-state Mode 10. This indicates that a 

particulate matter reduction of approximately 

19% is obtainable for this fuel and mode by 

changing the lubricant. It should be mentioned 

that this is a lower estimate for the oil impact on 

particulate at this operating condition since the 

oil might impact the fuel-VOF and non-VOF as 

well.

• As fuel-derived PM is reduced, either through 

fuel changes (as in this project) or fuel injection 

system improvements, the lubricant will become 

an even larger factor in PM emissions.

• Oil impacts nitrogen oxides through its effect on 

friction characteristics.

• With this set of data, the impact of lubricant on 

the light-duty FTP exhaust emissions is 

inconclusive.

Recommendations

• Since the results from this work suggest a high 

oil contribution to particulate emissions for lightload conditions, it is recommended that the effect 

of oil consumption on emissions be investigated 

Figure 7. Oil and Fuel Contribution to Particulate 

Emissions for the Fuel/Oil Combination 

Yielding the Lowest Oil Contribution to PM 

(CARB Fuel and 15W50 Synthetic Oil)

Figure 8. Oil Effect on Nitrogen Oxides for Average 

Steady-State Mode, Average across Fuels

Figure 9. Oil Effect on Carbon Dioxide Emissions for 

Average Steady-State Mode, Average across 

Fuels
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

40

in a vehicle using the FTP light-duty transient 

cycle.

• It is recommended that the effect of engine oil on 

polycyclic aromatic hydrocarbon emissions and 

insoluble PM be further investigated.

• The effects of ultra-low viscosity engine oil on 

exhaust emissions should be examined.

List of Publications

1. Abstract is submitted to the 2001 Spring Fuels & 

Lubricants Meeting & Exposition to be held in 

May 2001 in Orlando, FL.

List of Presentations

1. Presentation "Impact of Lube Oil on Advanced 

CIDI-Engine Emissions" at the DOE CIDI 

Combustion, Emission Control, and Fuels R&D 

Peer Review, May 24, in Argonne, Illinois

List of Acronyms

ADMM15 15% DMM and 85% low-sulfur fuel 

blend

CARB California reference fuel

DFI/GC direct filter injection gas 

chromatography

DMM dimethoxymethane

ft-lb foot-pound (torque)

FTP Federal Test Procedure

M5W30 Petroleum-based SAE 5W30 

crankcase oil

NOx oxides of nitrogen

PM particulate matter

RPM revolutions per minute

S5W30 Synthetic-based SAE 5W30 

crankcase oil

S15W50 Synthetic-based SAE 15W50 

crankcase oil

SAE Society of Automotive Engineers

VOF volatile organic fraction
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

41

III. FUEL & LUBRICANT EFFECTS ON EXHAUST EMISSION 

CONTROL DEVICES

A. Overview of the Diesel Emission Control-Sulfur Effects (DECSE) Program, 

Phase I

Wendy Clark (primary contact), George M. Sverdrup

Deputy Manager, DECSE Program

National Renewable Energy Laboratory

1617 Cole Boulevard

Golden, CO 80401

(303) 275-4468, fax: (303) 275-4415, e-mail: wendy_clark@nrel.gov

DOE Program Manager: Stephen J. Goguen

(202) 586-8044, fax: (202) 586-1600, stephen.goguen@ee.doe.gov

DOE Program Manager: John Garbak

(202) 586-1723, fax: (202) 586-9811, e-mail: john.garbak@ee.doe.gov

DOE Program Manager: Peter Devlin

(202) 586-4905, fax: (202) 586-4500, e-mail: Peter.Devlin@ee.doe.gov

Project Partners: Glenn Keller (Engine Manufacturers Association), Dale McKinnon (Manufacturers 

of Emission Controls Association), Michael J. Quinn (Caterpillar, Inc.), Ronald L. Graves (Oak 

Ridge National Laboratory)

This Project addresses the following OTT R&D Plan Barriers and Tasks:

Barriers

B. Fuel Property Effects on Exhaust Emission Control System Technology

D. Sulfur Impacts

Tasks

2. Fuel and Lubricant Properties - Engine-Out Emissions

3. Fuel and Lubricant Properties - Exhaust Emission Control and Emissions

Objectives

• Identify the effects of various levels of sulfur in diesel fuel on the operation of four types of exhaust 

emissions control technologies:

- Diesel oxidation catalysts.

- Active lean-NOx catalysts.

- Continuously regenerating diesel particulate filters (CR-DPF) and catalyzed diesel particulate 

filters (CDPF).

- NOx adsorber catalysts.

• Measure and compare the effects of up to 250 hours of aging at various fuel sulfur levels.
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

42

Approach

• The experimental design for the testing is shown in Table 1.

Accomplishments

• Four interim reports providing Phase 1 DECSE results are available at http://www.ott.doe.gov/decse/. 

• Completed work on NOx adsorber catalyst and diesel particulate filters.

• Completed work on fresh diesel oxidation and lean-NOx catalyst.

• Aging studies continuing on diesel oxidation and lean-NOx catalysts

Future Directions

• The DECSE program was the precursor to the Advanced Petroleum-Based Fuels-Diesel Emissions 

Control (APBF-DEC) Program. This government/industry program aims to identify the optimal 

combinations of fuels, lubricants, diesel engines, and emission control systems to maintain high fuel 

economy while meeting projected vehicle emission standards for the 2000 to 2010 time period. 

Table 1. Summary of Phase 1 Experimental Design

Introduction

The DECSE program was initiated in January 

1999 to determine the impact of various levels of 

diesel fuel sulfur on emission control systems whose 

use could lower emissions of NOx and PM from 

diesel on-highway trucks and light-duty vehicles. 

Existing and proposed emission standards require 

both light- and heavy-duty diesel emission control 

devices to achieve NOx and PM conversion 

efficiencies of approximately 90 percent. The U.S. 

Department of Energy, two national laboratories, the 

Engine Manufacturers Association, and the 

Manufacturers of Emission Controls Association 
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

43

support DECSE. The program is conducted by a 

government/industry steering committee.

Approach

The effect of various levels of sulfur [3 

(essentially sulfur free), 16 (NOx adsorber catalysts 

only), 30, 150, and 350 parts per million] on diesel 

oxidation catalysts (DOCs), lean-NOx catalysts, 

diesel particulate filters, and NOx adsorber catalysts 

was evaluated in the DECSE program. Engines used 

in the tests were selected to provide a representative 

source of diesel exhaust and various exhaust 

temperature profiles (see Table 2). Table 2 shows the 

emissions data collected.

Results

Fresh Diesel Oxidation Catalysts

• Sulfate conversion is temperature-dependent and 

varies with operating condition.

• Sulfur levels have a modest effect on 

hydrocarbons (HC) and no effect on carbon 

monoxide (CO) reduction efficiency.

• Particulate matter (PM) reduction efficiency is 

26 percent for 3-parts-per-million (ppm) sulfur 

levels, but with higher levels of sulfur there are 

significant increases in PM emissions at high 

exhaust temperatures.

• PM emissions increase (proportional to the 

amount of sulfur in the fuel) because of an 

increase in sulfate fraction (see Figure 1).

Fresh Lean-NOx Catalysts

• NOx emissions are reduced up to 30 percent at 

temperature ranges of 360o

 to 600oC.

Table 2. Emissions Data Collected

Figure 1. OICA Mode 2 (Peak Torque) PM EmissionsCummins ISM 370-DOC
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

44

• Post-catalyst total hydrocarbon (THC) emissions 

increase by a factor of 2 to 3 over engine-out 

emissions, and CO increases by a factor of 6 to 7.

• Sulfate emissions increase by a factor of 10 to 20 

for diesel fuels with levels of sulfur greater than 

150 ppm.

• At 3-ppm sulfur levels, PM reduction efficiency 

is 16 percent; however, with high-sulfur fuels 

(greater than 150 ppm), sulfate emissions 

increase by a factor of 10 to 20 (see Figure 2).

• At 150- and 350-ppm sulfur levels, sulfate 

emissions increase by a factor of 2 to 5 compared 

to 3-ppm sulfur levels.

• HC emissions increase by a factor of 2 to 3 and 

CO by a factor of 6 to 7. 

Continuously Regenerating Diesel Particulate 

Filters and Catalyzed Diesel Particulate Filters

• PM reduction efficiency is 95 percent when 

operating with 3-ppm sulfur fuel. However, at 

30-ppm sulfur levels, efficiency decreases to 72 

percent for CR-DPFs, and 74 percent for CDPFs, 

and drop to near zero when operating on 150-

ppm sulfur fuel (see Figure 3).

• HCs are reduced by 58 to 91 percent, and CO by 

90 to 99 percent, but these reductions are not 

affected by fuel sulfur levels.

• The conversion efficiency of fuel sulfur to 

sulfate particulate is 40 to 50 percent.

• DPF regeneration temperatures are higher with 

30-ppm fuel than with 3-ppm fuel.

NOx Adsorber Catalysts

• At 3-ppm sulfur levels, efficiency initially 

declines, then stabilizes up until 250 hours of 

operation.

• For operation less than 50 hours using 3 ppm 

fuel, NOx conversion efficiencies greater than 90 

percent are achieved. After 230 hours of 

operation, the conversion efficiency percentage 

is reduced to the mid 80s (see Figure 4).

• Conversion efficiencies with fuels containing 16 

and 30 ppm sulfur decline compared to 3 ppm 

sulfur levels after 150 hours of operation.

Conclusions

Tests of these NOx emission control devices 

suggest that they are feasible given very low sulfur 

Figure 2. Comparison of SO3 Emissions between 

Converter-out and Engine-out with the Fresh 

High-Temperature Lean NOx Catalyst 

(Cummins ISM Engine Mode 2)

Figure 3. PM Emissions Components as a Function of 

Fuel Sulfur Level, by Sulfur Portion and All 

Other PM for the OICA Cycle

Figure 4. Effect of Fuel Sulfur Level on an Engine 

Dynamometer Test of an NOx Adsorber (DC/

DDC 1.9 L prototype CIDI engine, steady-state 

testing)
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

45

content fuel. Tests using 3 ppm, 16 ppm, and 30 ppm 

sulfur fuel suggests that only the 3 ppm sulfur fuel 

enables the NOx emission control devices tested to 

meet emission standards when these devices are new 

(although after conditioning). Similarly, only the 3 

ppm fuel was shown to enable the PM emission 

control devices tested to meet the emission standards 

when relatively new (although full useful life 

certification has not been demonstrated) because 

higher sulfur fuels cause both catalyzed NOx and PM 

devices to produce sulfate PM from sulfur in the fuel.

List of Publications

1. U.S. Department of Energy. "Diesel Emission 

Control-Sulfur Effects (DECSE) Program Phase 

1 Interim Data Report," August 1999.

2. U.S. Department of Energy. "Diesel Emission 

Control-Sulfur Effects (DECSE) Program Phase 

1 Interim Data Report No. 2: NOx Adsorber 

Catalysts," October 1999.

3. U.S. Department of Energy. "Diesel Emission 

Control-Sulfur Effects (DECSE) Program Phase 

1 Interim Data Report No. 3: Diesel Fuel Sulfur 

Effects on Particulate Matter Emissions," 

November 1999.

4. U.S. Department of Energy. "Diesel Emission 

Control-Sulfur Effects (DECSE) Program Phase 

1 Interim Data Report No. 4," January 2000.

List of Acronyms

BSFC brake specific fuel consumption

C Celsius

CDPF catalyzed diesel particulate filter

CO carbon monoxide

CO2 carbon dioxide

CR-DPF continuously regenerating catalyzed 

diesel particulate filter

DECSE Diesel Emission Control-Sulfur 

Effects (program)

DOC diesel oxidation catalyst

DPF diesel particulate filter

HC hydrocarbon

N2 nitrogen

NOx nitrogen oxides

OICA International Organization of Motor 

Vehicle Manufacturers

PM particulate matter

ppm parts per million

SOF soluble organic fraction

SO2 sulfur dioxide

SO3 sulfate

THC total hydrocarbons
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

46

B. NOx Adsorber Testing with Fuels of Varying Sulfur Content

Peg Whalen (primary contact), Wendy Clark

National Renewable Energy Laboratory

1617 Cole Boulevard

Golden, CO 80401

(303) 275-4479, fax: (303) 275-4415, e-mail: peg_whalen@nrel.gov

DOE Program Manager: Peter Devlin

(202) 586-4905, fax: (202) 586-4500, e-mail: Peter.Devlin@ee.doe.gov

DOE Program Manager: Stephen J. Goguen

(202) 586-8044, fax: (202) 586-1600, e-mail: Stephen.Goguen@ee.doe.gov

Subcontractor: FEV Engine Technology, Inc., Auburn Hills, MI

Other Participants: Technical team with representation from Manufacturers of Emission Control 

Association (MECA), Engine Manufacturers Association (EMA), Oak Ridge National Laboratory 

(ORNL), Battelle Memorial Institute

This Project addresses the following OTT R&D Plan Barriers and Tasks:

Barriers

B. Fuel Property Effects on Exhaust Emission Control System Technology

C. Emission Control System Degradation

Tasks

2. Fuel and Lubricant Properties - Engine-Out Emissions

3. Fuel and Lubricant Properties - Exhaust Emission Control and Emissions

Objectives

• To optimize the oxides of nitrogen (NOx) regeneration calibration developed in the Diesel Emission 

Control-Sulfur Effects (DECSE) Phase 1 effort, achieving 80+% NOx conversion efficiency over the 

operating temperature range.

• To develop and demonstrate a NOx adsorber desulfation process to enable NOx conversion efficiency 

recovery from sulfur poisoning.

Approach

• A 1.9 L high-speed, direct-injection (HSDI) diesel engine with common rail injection and complete 

instrumentation package used to:

- Complete the optimization of the NOx regeneration calibration, and remap performance of the 

catalyst pairs tested in Phase 1 using the improved calibration.

- Develop a desulfation process using a spare aged catalyst.

- Evaluate the ability of the desulfation strategy to recover NOx conversion efficiency using the 

catalyst poisoned in the Phase 1 testing.

- Further investigate the desulfation process using new catalysts, and a series of aging cycles 

followed by desulfation events. 
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

47

Accomplishments

• Developed an improved NOx regeneration strategy, which achieved greater than 90% NOx conversion 

with a fresh catalyst.

• Developed desulfation strategy to recover NOx conversion efficiency from a sulfur poisoned catalyst.

• Desulfurized catalysts poisoned with 3-parts per million (ppm), 16-ppm and 30-ppm sulfur fuel. NOx

conversion efficiency recovered to more than 80% in each case.

• Achieved similar NOx conversion recovery in aging/desulfation cycling tests on fresh catalyst pairs 

aged with two different sulfur level fuels (3-ppm and 75-ppm).

Future Directions

• Evaluations of NOx adsorber technologies will continue under the Advanced Petroleum-Based FuelsDiesel Emissions Control (APBF-DEC) Program. Representatives of government agencies, trade 

associations, and private industry are jointly funding Phase 2 to identify the optimal combinations of 

fuels, lubricants, diesel engines, and emission control systems to maintain high fuel economy while 

meeting projected emission standards for the 2000 to 2010 time period. The program will also identify 

properties of fuels and vehicle systems that could lead to even lower emissions beyond 2010.

Introduction

This project was initiated in FY99 under the 

DECSE program, a joint government/industry 

program to determine the impact of diesel fuel sulfur 

levels on emissions control systems (see report 

III.A.). NOx adsorber catalysts were one of four 

emission control technologies selected for evaluation 

during Phase 1 of this project.

A NOx adsorber catalyst is a flow-through 

emissions control device that has the potential to 

lower NOx, hydrocarbons (HC) and carbon 

monoxide (CO) emissions from diesel engine 

exhaust. It is a temporary storage device for NOx. 

During typical diesel engine operation, the device 

stores NOx from the lean exhaust gas as a nitrate on 

the catalyst surface. Before the device is fully 

saturated with nitrate, engine operating and fueling 

conditions are adjusted to produce a fuel-rich 

exhaust. Under the rich conditions, the nitrate is 

released and simultaneously reduced to molecular 

nitrogen by the adsorber catalyst. The duration and 

air-to-fuel ratio of the rich pulse is critical. If it is too 

long or too rich, HC and CO can break through the 

adsorber, resulting in poor control of these pollutants 

and reduced fuel economy. If it is too short, 

incomplete regeneration occurs. These devices are 

susceptible to sulfur poisoning from the sulfur 

contained in diesel fuel.

The Phase 1 effort illustrated the effect of sulfur 

in the fuel on NOx conversion efficiency, but the 

initial calibration of the engine management system 

did not achieve the desired level of NOx conversion 

performance over the range of operating 

temperatures. This follow-on effort was undertaken 

to optimize the NOx regeneration strategy (to 

improve NOx conversion), and to investigate 

desulfation of NOx adsorber catalysts that have been 

poisoned by sulfur in diesel fuel. 

Approach

The 1.9 L HSDI diesel engine equipped with a 

common rail fuel injection system that was used in 

DECSE Phase 1 was installed in the test cell at FEV 

Figure 1. Catalyst Installation in Test Cell
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

48

Engine Technologies (see Figure 1). Installation of 

the same instrumentation package as utilized in the 

Phase 1 effort was completed. The exhaust system 

was set up to divide the exhaust supplied to the two 

catalysts in parallel, with butterfly valves installed to 

balance the flow through the catalysts.

The initial focus of this project involved 

modification of the conditions for regeneration to 

improve and achieve the highest NOx conversion 

efficiency possible. FEV first investigated varying 

engine operating conditions including exhaust gas 

recirculation (EGR) level, throttling, main injection 

start, post injection start and the quantity of post 

injection. The second part of the optimization 

focused more on the characteristics of the catalyst. 

Both the lean and rich operating times were varied to 

maximize NOx conversion while minimizing 

additional fuel use.

The next task was to remap the performance of 

the catalyst pairs previously tested in Phase 1, using 

the newly optimized NOx regeneration strategy. All 

catalyst performance maps were run at an engine 

speed of 3000 rpm, at catalyst inlet temperatures 

ranging from 250o

C to 500oC with the engine 

running on 3-ppm sulfur level diesel fuel.

The remainder of this project focused on 

developing a desulfation procedure to enable the NOx

adsorber catalyst to recover conversion efficiency 

lost due to sulfur poisoning of catalyst sites. During 

development of the desulfation process, catalysts 

were poisoned until their conversion ratio had fallen 

by 25%. Desulfurization required certain conditions, 

including a relatively high catalyst inlet temperature 

and rich engine operation. MECA indicated that the 

appropriate target temperature was 700o

C. An air-tofuel ratio of 0.9 was expected to achieve desulfation 

in a reasonable time period. The desulfation 

procedure was further demonstrated by attempting to 

release sulfur from the catalyst pairs tested under the 

DECSE Phase 1 project. 

The final task of this project was to investigate 

the ability of the NOx adsorber to maintain 

performance over several aging and desulfation 

cycles. This testing started with two new pairs of 

catalyst, which were degreened for 10 hours and 

aged for 10 hours. Each pair of catalysts was put 

through a series of aging, performance map, 

desulfation, and remapping cycles. The only 

difference in the testing of the two pairs was that 

aging was completed using 3-ppm sulfur fuel for one 

and 75-ppm sulfur fuel for the other.

Figure 2. NOx conversion efficiency from DECSE 1 

optimized calibration compared to efficiency 

of catalyst with similar number of operating 

hours mapped with the calibration developed 

in this project

Figure 3. Summary of NOx conversion efficiencies from 

different regeneration calibrations
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

49

Results

Efforts to improve the NOx regeneration strategy 

over that developed under the DECSE 1 project were 

fairly successful, especially in the mid-range of the 

temperature window investigated (300o

C to 450oC). 

Figure 2 displays NOx conversion efficiency from the 

DECSE 1 optimized calibration (10c and 10d) 

compared to calibration developed in this Phase 2 

project (S4). These results are for tests at an engine 

operating speed of 3000 rpm using 3-ppm sulfur fuel. 

The catalyst compared had a similar amount of 

accumulated operating hours or aging.

Figure 3 shows NOx conversion efficiency for 

calibrations developed under the DECSE 1 and 2 

projects, including a fresh catalyst pair (S5 and S6), 

which was degreened and aged. With the exception 

of the 250o

C point, the fresh catalyst achieved in 

excess of 80% NOx conversion efficiency over the 

range of operating temperatures and in excess of 

90% conversion efficiency over the mid-range 

temperatures. The catalyst manufacturer indicated 

that this catalyst would not achieve the 80+% 

conversion target at 250o

C. These conversion 

efficiency levels were achieved while staying within 

the 4% fuel economy penalty target defined at the 

start of the project. 

The basic requirements to achieve sulfur release 

from a poisoned NOx adsorber catalyst include high 

catalyst inlet temperature and rich engine operation. 

MECA representatives recommended temperatures 

in the range of 700o

C. In order to reach this 

temperature range, it was necessary to install a 

warm-up catalyst during the development and 

operation of the desulfation procedure.

Development of the desulfation process was 

conducted using the S4 catalyst, with all desulfation 

events conducted using 3-ppm fuel. The conversion 

efficiency was checked before and after desulfation 

at the 400o

C operating temperature. The catalyst was 

poisoned to a target of 60% NOx conversion 

efficiency between each desulfation. Poisoning was 

accomplished with 330-ppm sulfur (wt %) 

commercial Amoco diesel fuel. The 60% target 

represented a 25% reduction in efficiency from the 

original conversion efficiency at the 400o

C operating 

temperature. The length of the desulfation event was 

varied from one to seven minutes to establish the 

optimum desulfation duration (results displayed in 

Figure 4). With increasing desulfation event 

duration, the percent conversion ratio recovery 

increased up to a maximum of about 43% at a sixminute duration. This corresponds to an absolute 

conversion efficiency of just over 84%, which was 

higher than the initial NOx conversion efficiency at 

the 400o

C operating point. 

The desulfation strategy was then used to release 

sulfur from the three catalyst pairs tested under the 

DECSE 1 project. These catalysts had been aged 

Figure 4. Results from development of desulfation 

strategy

Figure 5. NOx conversion efficiency of DECSE Phase 1 

catalysts aged with 3-ppm sulfur fuel before 

and after desulfation
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

50

using 3-ppm, 16-ppm, and 30-ppm sulfur fuel, and 

had been aged for 250, 200, and 150 hours, 

respectively. The performance of each of these 

catalyst pairs had been remapped using the improved 

NOx regeneration strategy developed in this project. 

The NOx conversion efficiency was improved over 

the DECSE 1 calibration results for each of the 

catalyst pairs. 

A six-minute desulfation event was conducted on 

each of the catalyst pairs. Figure 5 demonstrates the 

results. The figure presents performance maps for the 

catalyst pair aged with 3-ppm sulfur fuel. There was 

a clear improvement in the conversion performance 

with the revised NOx regeneration calibration 

(squares compared to circles). Following the 

desulfation event, there was significant recovery in 

the NOx conversion efficiency. The recoveries in the 

catalysts aged with 16-ppm and 30-ppm sulfur fuel 

were even more dramatic, as both had lower predesulfation conversion efficiency than the catalysts 

aged with 3-ppm fuel. Figure 6 shows the postdesulfation results for the catalysts originally aged 

with 3-ppm (3A & 3B), 16-ppm (16A & 16B) and 

30-ppm (30A & 30B) sulfur level fuels. Each of the 

catalyst pairs returned to similar, high levels of NOx

conversion performance. Although not investigated 

in this study, it is worthwhile to note that there will 

also be a fuel economy impact associated with 

desulfurization, which will depend on the frequency 

of desulfurization events.

The final task was to conduct a series of agingperformance map-desulfation-performance map 

cycles on two fresh sets of catalysts. Initially each 

catalyst pair was degreened for ten hours, and aged 

for ten hours using 3-ppm sulfur fuel. Six testing 

cycles were conducted on each catalyst pair. Aging of 

one catalyst pair was done with 3-ppm sulfur fuel; 

75-ppm fuel was used for the other pair.

An example of the type of results obtained is 

provided in Figure 7. This plot shows the post-aging 

and post-desulfation NOx conversion efficiency of 

the two catalyst pairs at the 400o

C operating 

temperature. Following each aging, the NOx

conversion performance of the catalysts aged with 

75-ppm sulfur tended to be lower than that of the 

catalyst exposed to 3-ppm sulfur fuel. However, both 

pairs of catalysts recovered to similar levels of NOx

conversion efficiency following desulfation. The 

NOx conversion efficiency tends to decrease with 

increased age for both catalyst pairs. It is not clear at 

this point whether this decrease is a thermal effect 

that will stabilize, or a poisoning effect that is not 

completely released.

Figure 6. NOx conversion efficiency of DECSE Phase 1 

catalysts following desulfation

Figure 7. NOx conversion efficiency of catalyst pairs 

aged with 3-ppm and 75-ppm sulfur fuel, 

following each aging and each desulfation 

cycle at the 400o

C operating temperature
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

51

Conclusions

This project proved successful in meeting its 

primary objectives of improving the NOx

regeneration strategy (developed under DECSE 

Phase 1) and of developing a desulfation procedure. 

An improved NOx regeneration strategy was 

demonstrated. In fresh catalysts, NOx conversion 

efficiencies in excess of 90% at catalyst inlet 

temperatures from 300o

C to 450oC were achieved. 

The DECSE Phase 1 effort showed that even 

relatively low sulfur level fuels can have a significant 

impact on the NOx conversion efficiency of NOx

adsorber catalysts. In DECSE 2 demonstration tests, 

the desulfation process returned the NOx adsorber 

catalyst to a high level of NOx conversion efficiency. 

List of Publications

1. U.S. Department of Energy. "Diesel Emission 

Control-Sulfur Effects (DECSE) Program Phase 

1 Interim Data Report No. 2: NOx Adsorber 

Catalysts," October 1999.

List of Presentations

1. Windsor Workshop, June 2000

2. SAE Clean SUV & Light Truck TOPTEC, June 

2000

3. CEC/SAE International Fuels & Lubricants 

Meeting, June 2000

List of Acronyms

CO carbon monoxide

DECSE Diesel Emission Control-Sulfur 

Effects Program

EGR exhaust gas recirculation

EMA Engine Manufacturers Association

HC hydrocarbons

HSDI high-speed, direct-injection

MECA Manufacturers of Emission Controls 

Association

NOx oxides of nitrogen

ORNL Oak Ridge National Laboratory
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

52

C. Evaluation of Advanced Petroleum-Based Fuels in a Mercedes Benz "C" Class 

CIDI Vehicle

Edwin A. Frame (primary contact), Karl E. Stoecklein, Kevin Whitney

Southwest Research Institute

6220 Culebra Road

San Antonio, TX 78238-5166

(210) 522-2515, fax (210) 522-3270, e-mail: eframe@swri.edu

DOE Program Manager: John Garbak

(202) 586-1723, fax: (202) 586-9811, e-mail: john.garbak@ee.doe.gov

This Project addresses the following OTT R&D Plan Barriers and Tasks:

Barriers

A. Fuel Property Effects on Engine Emissions and Efficiency

Tasks

2. Fuel and Lubricant Properties - Engine-Out Emissions

Objective

• Quantify the exhaust emission benefits of selected advanced petroleum-based fuels in a vehicle 

powered by a state-of-the-art CIDI engine (OM611).

Approach

• Seven fuels were chosen that had been evaluated in steady-state emission tests of the OM611 engine in 

FY 1999.

• Tailpipe exhaust emissions from a European-specification Mercedes Benz "C" (C220) series vehicle 

were measured for all fuels following the chassis dynamometer portion of the Federal Test Procedure 

(FTP), and the US06 aggressive driving cycle. Selected fuels were evaluated over the ECE15/EUDC 

European Driving Cycle. 

Accomplishments

• All fuels tested in the vehicle had exhaust emissions that are greater than the EPA Tier 2 standards.

• Test cycle severity with respect to particulate matter (PM) and NOx was as follows: US06 was the 

most severe, followed by the FTP, with the ECE+EUDC being the least severe.

• The fuel blend containing 15% dimethoxymethane (DMM) consistently produced the lowest PM, and 

a slight increase in NOx levels across all test cycles.

• The DMM15 fuel consistently produced the lowest volatile organic fraction (VOF) of PM.

• Fuel economy for the DMM15 fuel ranged from 8 to 11% less than the 2D baseline fuel.

Future Directions

• Evaluate the effect on vehicle exhaust emissions of selected oxygenate compounds that were identified 

in DOE Project "The Oxygenates for Advanced Petroleum-Based Diesel Fuel".

• Evaluate vehicle exhaust emissions of other advanced petroleum-based fuels such as ultra-low sulfur 

diesel and other oxygen containing fuel blends.
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

53

Introduction

Potential exhaust emission reductions have been 

demonstrated in many previous studies for 

alternative and reformulated diesel fuels. In the 

current investigation, exhaust emissions were 

determined from a Mercedes Benz "C" Series 

European-specification vehicle for a series of 

advanced petroleum-based fuels (Table 1) that had 

been tested previously under steady-state conditions 

in the OM611 engine. The vehicle is powered by the 

OM611 engine, which has a displacement of 2.2 L, 

and has the following characteristics: directinjection, four valves per cylinder, turbocharged and 

intercooled, high-pressure common rail fuel injection 

system with pilot injection, exhaust gas recirculation, 

and intake port cut-off. This engine closely matches 

the specifications of the Partnership for a New 

Generation of Vehicles (PNGV) target CIDI engine 

except for a slightly larger displacement. According 

to the vehicle manufacturer, the emission control 

system of the C 220 Turbodiesel vehicle includes one 

catalytic converter close to the engine with a volume 

of 2.1 L, and an additional underbody catalytic 

converter with a volume of 1.8 L. Both converters 

have a platinum coating on a zeolith substrate and 

provide oxidation of HC and CO with a slight 

reduction in NOx. The converter closest to the 

engine has an internal by-pass so that the underbody 

converter is supplied with hydrocarbons to assist in 

an additional slight reduction in NOx. Figure 1 is a 

photograph of a Mercedes Benz C220 Turbodiesel 

vehicle undergoing testing.

Approach

All seven test fuels shown in Table 1 were 

evaluated over the chassis dynamometer portion of 

the Federal Test Procedure (FTP), and US06 

aggressive driving cycle. In addition, selected fuels 

were evaluated over the ECE15/EUDC European 

Driving Cycle. The complete test matrix is shown in 

Table 2. 

Exhaust constituents were analyzed as specified 

below:

Results

Exhaust emissions data for all fuels and all test 

cycles are presented in Figure 2. All testing was 

conducted in triplicate. Percent changes in exhaust 

emissions and fuel economy from the baseline 2D 

fuel are presented in Table 3. The shaded areas in the 

table are statistically significant results. Compared 

to 2D fuel, the following statistically significant 

results are noted: in the FTP, DMM15 fuel produced 

40% reduction in PM and a 16% increase in NOx. In 

Fuel Code Fuel Description

2D 2-D EPA Certification Diesel

CA California Reference Diesel

LS Low Sulfur Diesel

FT100 Neat Fischer-Tropsch Diesel

DMM15 15% DMM with 85% LS Diesel

FT20 20% Fischer-Tropsch with 80% LS 

Diesel

B20 20% Biodiesel with 80% LS Diesel

Table 1. Test Fuels

Figure 1. Mercedes-Benz C220 Undergoing Testing

Constituent Analysis Method

Total Hydrocarbon Heated Flame Ionization 

Detector

Carbon Monoxide Non-Dispersive Infrared 

Analysis

Carbon Dioxide Non-Dispersive Infrared 

Analysis

Oxides of Nitrogen Chemiluminescent Analysis

Particulate Matter Gravimetric

Volatile Organic 

Fraction of PM

Direct Filter Injection Gas 

Chromatography

Oil Fraction of VOF Direct Filter Injection Gas 

Chromatography

Sulfate Portion of PM Ion Chromatography
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

54

the FTP, all other test fuels had increased PM 

compared to the 2D fuel. This unexpected increase 

in PM was attributed to better catalytic converter 

response to the 2D fuel during the FTP. In the US06 

test, there was no significant difference in PM for all 

fuels tested. DMM15 had a 14% increase in NOx. In 

the ECE+EUDC test, DMM15 resulted in a 63% 

decrease in PM with a 26% increase in NOx 

compared to 2D fuel. The LS and FT100 fuels also 

had statistically significant reductions in PM during 

the European test cycle. Fuel economy for the 

DMM15 fuel ranged from 8 to 11% less (volumetric) 

than the 2D baseline fuel over the test cycles.

In addition to the dilute exhaust samples, raw 

exhaust emissions were recorded on a second-bysecond "modal" basis for THC, CO, and NOx prior to 

the close-coupled catalyst (engine-out) and following 

the underbody catalyst (tailpipe-out). Catalyst 

efficiency was calculated and is presented in Table 4. 

Catalyst efficiency for total hydrocarbons (THC) 

varied from 86-95%. The lowest estimated catalyst 

efficiencies were obtained during the European test 

cycles that operate at a lower exhaust temperature.

Particulate samples were analyzed to determine 

the particulate volatile organic fraction (VOF), the 

contribution of unburned lubricating oil to VOF, and 

the sulfate fraction of the particulate. These results 

are presented in Table 5. Sulfate levels were highest 

over the US06. The DMM15 fuel consistently had 

the lowest levels of VOF over all test cycles. In 

general, there were no large differences in the 

percentage of unburned oil in the VOF among the 

fuels.

Conclusions

All fuels tested in the C220 vehicle had exhaust 

emissions that were greater than EPA Tier 2 

standards. With respect to test cycle severity, the 

US06 was the most severe, followed by the FTP and 

then the European cycles. The fuel blend containing 

15% DMM consistently produced the lowest PM 

emissions; however, a slight increase in NOx was 

observed. DMM15 fuel consistently had the lowest 

levels of VOF. Fuel economy for the DMM15 fuel 

ranged from 8-11% less (volumetric) than the 2D 

baseline fuel.

List of Presentations

1. Preliminary results were presented during a 

Poster Session at the DOE peer review on May 

23, 2000 at Argonne National Laboratory.

List of Acronyms

CIDI compression ignition direct injection

CO carbon monoxide

CO2 carbon dioxide

DMM dimethoxymethane

ECE+EUDC European test cycles

EPA Environmental Protection Agency

Test Cycle

Fuel FTP US06 

Aggressive 

Driving Cycle

European 

ECE+EUDC

2D √√√

CARB √ √ X

LS √√√

FT100 √√√

FT20/LS √ √ X

B20/LS √ √ X

DMM15/

LS

√√√

√ = Tests Completed

X = Not Included in Test Matrix

Table 2. Test Matrix

Figure 2. Preliminary Emissions Data for All Fuels and 

All Test Cycles
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

55

FE Fuel Economy

FTP Federal Test Procedure

L liter

NOx oxides of nitrogen

PM particulate matter

PNGV Partnership for a New Generation of 

Vehicles

THC Total hydrocarbons

US06 Aggressive Driving Test Cycle

VOF Volatile Organic Fraction

Cycle Measurement LS, % FT100, % DMM15, % CARB, % B20, % FT20,%

FTP HC (g/mi) -56 -52 -54 -3 -54 -74

CO (g/mi) -73 -54 -66 -33 -58 -52

NOx (g/mi) -2 -3 16 -5 -2 -4

PM (g/mi) 39 14 -40 11 12 27

FE (mi/gal) -3 -5 -9 -3 -3 -3

US06 HC (g/mi) -5 -52 -27 -21 -64 -45

CO (g/mi) -2 14 -64 -43 -1 62

NOx (g/mi) -2 -3 14 -2 -2 -5

PM (g/mi) 26 -14 -20 1 -12 2

FE (mi/gal) -4 -6 -8 -1 -3 -3

ECE HC (g/mi) -69 -74 -78

CO (g/mi) -61 -74 -64

NOx (g/mi) 3 4 26

PM (g/mi) -15 -19 -63

FE (mi/gal) 0 -12 -11

Note: shaded areas denote statistically significant changes from 2D baseline

Table 3. Percent Change from 2D Baseline Fuel

Test Cycle Fuel Catalyst Efficiency, percent

THC CO

FTP 2D 95 97

DMM15 93 98

FT100 90 98

LS 94 97

B20 92 98

FT20 90 98

CARB 94 97

US06 2D 94 99

DMM15 92 99

FT100 92 99

LS 94 98

B20 92 99

FT20 90 99

CARB 93 99

ECE 2D 90 81

DMM15 90 85

FT100 86 86

LS 87 86

Table 4. Estimated Catalyst Efficiency
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

56

Test Cycle Fuel Total PM, mg/

mi

Wet Sulfate, 

mg/mi a VOF, mg/mi Unburned Oil, 

% (+/- 10%)

ECE 2D 52.8 0.44 6.55 18

DMM15 19.9 0.36 3.52 < 9

FT100 42.6 0.50 6.71 14

LS 45.0 0.42 4.76 32

FTP 2D 53.0 0.13 7.96 30

B20 58.6 0.20 6.55 27

CARB 58.9 0.25 9.19 20

DMM15 31.7 0.47 6.11 < 9

FT100 60.2 0.60 8.64 11

FT20 66.9 0.25 9.67 21

LS 73.7 0.71 10.34 16

US06 2D 92.7 4.05 5.75 14

B20 81.7 2.69 4.05 17

CARB 93.0 6.91 6.02 23

DMM15 74.0 3.89 3.00 < 9

FT100 80.0 3.50 5.22 14

FT20 95.3 2.01 4.70 14

LS 117.0 2.14 5.46 9

a

 Total includes "dry" sulfate value plus associated water of hydration

Table 5. Breakdown of Particulate Emissions
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

57

D. NOx and PM Emission Control Device Evaluation in a Mercedes-Benz 1.7L 

CIDI Vehicle

Brian H. West and C. Scott Sluder

Oak Ridge National Laboratory

P.O. Box 2009

Oak Ridge, TN 37831-8087

(865) 574-0248, fax:(865) 574-2102, e-mail: westbh@ornl.gov or sluders@ornl.gov

DOE Program Manager: Peter Devlin

(202) 586-4905, fax: (202) 586-4500, e-mail: Peter.Devlin@ee.doe.gov

This Project addresses the following OTT R&D Barriers and Tasks:

Barriers

B. Fuel Property Effects on Exhaust Emission Control System Technology

C. Emission Control System Degradation

Tasks

2. Fuel and Lubricant Properties - Engine-Out Emissions

3. Fuel and Lubricant Properties - Exhaust Emission Control and Emissions

Objectives

• Demonstrate the potential effectiveness of near-term NOx and PM emissions control technologies 

using a light-duty CIDI vehicle during transient certification-type tests.

• Investigate the short-term effects of fuel-sulfur level on the effectiveness of these technologies.

Approach

• Conduct repetitive chassis-dynamometer evaluations of a 1999 Mercedes A170 CDI using fuels with 

varying sulfur levels. Perform these evaluations with the vehicle equipped with its original catalysts, 

with no emissions control devices whatsoever, with a catalyzed diesel particulate filter installed, and 

with a NOx adsorber installed. Utilize the FTP and US06 driving schedules. Design and implement a 

regeneration system (using bottled gases) for the NOx adsorber as necessary to accomplish these 

evaluations.

Accomplishments

• Demonstrated, in a laboratory experiment, that a catalyzed diesel particulate filter (degreened, low 

mileage) can provide greater than 95% reduction in particulate emissions compared with the engineout emissions levels on the FTP and US06 driving schedules.

• Demonstrated, in a laboratory experiment, that a NOx adsorber (degreened, low mileage) can provide 

92% reduction in NOx emissions compared with engine-out emissions levels on the FTP driving 

schedule, and 89% reduction on the US06 driving schedule.

• Showed that the equivalent of a 3,000 mile exposure to 30-ppm sulfur fuel degraded NOx adsorber 

performance. After sulfur poisoning, NOx adsorber effectiveness was reduced to only 80% on the FTP, 

and reduced to only 66% on the US06 cycle.
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

58

• Showed that the short-term effects of fuel sulfur on the catalyzed diesel particulate filter and the 

original-equipment catalysts were not statistically significant.

Future Directions

• Demonstrate simultaneous control of the four regulated pollutants (carbon monoxide, nitrogen oxides, 

unburned hydrocarbons, and particulate matter) using both the NOx adsorber and catalyzed diesel 

particulate filter technologies together with a more refined control system/strategy.

• Investigate the effects of exhaust temperature, exhaust chemistry, and regeneration strategy on the 

performance of these devices when used together in an emissions control system.

Introduction

Lean-burn direct-injection engines (both 

compression-ignition and spark-ignition) offer the 

possibility of very significant fuel efficiency gains. 

Unfortunately, both of these engine technologies 

present NOx and PM emissions challenges that must 

be overcome if they are to meet future emissions 

reduction targets (Figure 1). To this end, a great deal 

of research has been conducted to develop new 

emissions control technologies that can reduce both 

PM and NOx emissions from lean-burn engines. 

However, these technologies can require large capital 

expenditures by the nation’s industries and some 

questions remain as to whether these technologies, if 

implemented, can enable lean-burn engines to reach 

the EPA Tier 2 emissions standards. These questions 

are particularly applicable to compression-ignition, 

direct-injection (CIDI) engines. The Diesel Vehicle 

Emissions Control Sulfur Effects (DVECSE) project 

aimed to demonstrate the potential reductions that 

new emissions control technologies may provide, 

and to investigate the short-term impact of fuel sulfur 

on these potential reductions. The project was a 

laboratory experiment with the goal of providing 

information; many issues (including reliability) 

remain to be solved before these technologies can be 

considered commercially viable.

Approach

A 1999 Mercedes A170 CIDI (Figure 2) was 

used as the testbed for this project. The Mercedes 

was selected because it is equipped with an 

advanced, common-rail direct-injection, 

turbocharged diesel engine with exhaust gas 

recirculation. The engine is 1.7 liters in 

displacement, making it of the approximate size 

targeted by the PNGV program. The emissions from 

the A170 as equipped with its factory catalytic 

converters and without any emissions control devices 

(engine-out emissions) were first measured as 

baselines for comparison. The Mercedes was then 

equipped (one-at-a-time) with a catalyzed diesel 

particulate filter (CDPF) and a NOx adsorber that 

were provided by the Manufacturers of Emissions 

Controls Association (MECA). Repetitive FTP and 

Figure 1. Current (Tier 1) and Future (Tier 2) Emissions 

Levels

Figure 2. 1999 Mercedes A170 CIDI Research Vehicle
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

59

US06 tests were conducted on each of these devices 

with fuels of varying sulfur level. A regeneration 

system was developed to allow regeneration of the 

NOx adsorber during these transient tests without the 

need for engine modifications. This regeneration 

system utilized bottled gases (CO, C2H4, and H2) 

together with the engine exhaust stream to mimic 

exhaust conditions that can be generated using latecycle in-cylinder injection of diesel fuel. Late-cycle 

injection is a likely means for generating exhaust 

conditions necessary for actively-controlled 

emissions control technologies. It was not possible 

to utilize late-cycle injection for this project given 

time and funding constraints.

The factory oxidation catalysts had no significant 

effect on NOx, but reduced PM emissions by 30-

40%. This reduction was primarily accomplished 

through oxidation of the soluble organic fraction of 

the PM, and is not adequate to reach PM reduction 

targets. The factory catalysts were very effective at 

reducing CO and hydrocarbon emissions. No 

statistically significant impact from fuel sulfur on the 

oxidation catalysts was found.

The CDPF reduced CO and hydrocarbon 

emissions at approximately the same effectiveness as 

the factory oxidation catalysts and had no significant 

effect on NOx emissions compared with the factory 

catalysts and engine-out emissions results. However, 

the CDPF reduced PM emissions by more than 95% 

compared with engine-out results. Measured PM 

emissions for the FTP and US06 cycles were less 

than 0.01 grams per mile (g/mi), even during 

regeneration. (Regeneration of a CDPF is the desired 

effect of burning of stored particulate caused by a 

combination of exhaust heat and catalytic coatings 

on the CDPF.) Fuel sulfur to sulfate PM conversion 

was found to be negligible during the FTP and US06 

cycles, and was only significant during regeneration 

when the 150 ppm sulfur fuel was used. Even during 

this case, the PM emissions remained at or below 

0.01 g/mi. 

The NOx adsorber reduced NOx emissions by 

92% (to 0.05 g/mi) on the FTP cycle and by 89% (to 

0.14 g/mi) on the US06 cycle. These reductions 

were achieved at the expense of hydrocarbon and CO 

emissions. HC and CO increased somewhat from 

regeneration (purging and chemical reduction of the 

stored NOx), but generally remained at or near Tier 2 

targets. However, with a more refined regeneration 

system and strategy, reduction in the hydrocarbon 

and CO emissions is thought to be possible. A short 

exposure (equivalent to 3,000 miles using 30 ppm 

sulfur fuel) to higher sulfur fuel resulted in serious 

degradation in the performance of the NOx adsorber. 

After this exposure, the reduction in NOx emissions 

dropped to only 80% on the FTP and 66% on the 

US06 as compared with the engine-out results.

Conclusions

The CDPF and the NOx adsorber show great 

promise for enabling light-duty CIDI vehicles to 

meet future emissions targets (Figure 3), however 

considerable development is still needed. Engine 

controls adequate to provide the exhaust conditions 

necessary for regeneration of a NOx adsorber and 

CDPF are not yet available, and no long-term 

reliability studies have yet been conducted. 

Furthermore, it is clear that the NOx adsorber 

technology will likely require a means of sulfur 

protection (sulfur traps, de-sulfurization, etc) in 

addition to lower sulfur fuels.

List of Publications

1. C. Scott Sluder and Brian H. West. "Catalyzed 

Diesel Particulate Filter Performance in a LightDuty Vehicle." Submitted for publication at the 

Society of Automotive Engineers 2000 Fall Fuels 

and Lubricants Meeting.

Figure 3. NOx and PM Reductions Demonstrated in This 

Project
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

60

2. Brian H. West and C. Scott Sluder. "NOx

Adsorber Performance in a Light-Duty Diesel 

Vehicle." Submitted for publication at the 

Society of Automotive Engineers 2000 Fall Fuels 

and Lubricants Meeting.

List of Presentations

1. Presentation to the Department of Energy, March 

15-16, 2000.

2. Presentation to the Department of Energy, March 

28, 2000.

3. Presentation at the Ford Sci-Lab, March 29, 

2000.

4. Presentation to the Environmental Protection 

Agency, March 30, 2000.

5. Presentation to Navistar International, May 12, 

2000.

6. Presentation at the Society of Automotive 

Engineers SUV TOPTEC, June 9, 2000.

7. Presentation to Cummins Engine Company, June 

12, 2000.

8. Presentation at the Oak Ridge National 

Laboratory On-Site Review, June 22, 2000.

List of Acronyms

CDPF Catalyzed diesel particulate filter

CIDI Compression ignition direct 

injection

CO Carbon monoxide

DVECSE Diesel Vehicle Emissions Control 

Sulfur Effects

EPA Environmental Protection Agency

FTP Federal Test Procedure

MECA Manufacturers of Emissions 

Controls Association

NOx Oxides of nitrogen

PM Particulate matter

US06 Aggressive driving test cycle
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

61

E. EC-Diesel Technology Validation Program

Keith Vertin 

National Renewable Energy Laboratory

1617 Cole Boulevard

Golden, CO 80401

(303)275-4422, fax: (303)275-4415, e-mail: keith_vertin@nrel.gov 

DOE Program Manager: Stephen Goguen

(202)586-8044, fax: (202)586-4166, e-mail: Stephen.Goguen@ee.doe.gov

Subcontractors: West Virginia University, Morgantown, WV; Battelle, Columbus, OH

This Project addresses the following OTT R&D Plan Barriers and Tasks:

Barriers

B. Fuel Property Effects on Exhaust Emission Control System Technology

Tasks

3. Fuel and Lubricant Properties - Exhaust Emission Control and Emissions

Objectives

• Compare exhaust emissions from vehicles fueled with EC-Diesel and California diesel fuels. ECDiesel is an ultra-low sulfur diesel fuel with 15 ppm maximum sulfur content.

• Evaluate the performance, emissions, and durability of the vehicles retrofitted with catalyzed particle 

filters and fueled with EC-Diesel over twelve or more months of service.

• Collect fuel consumption, maintenance, reliability, and operating cost data for the participating vehicle 

fleets and compare to control vehicles fueled with California diesel fuel.

Approach

• Establish a government and industry working group to direct the program. 

• Select participating vehicle fleets in Southern California.

• Retrofit a select number of vehicles with catalyzed particle filters and assist with start-up of the test 

fleets.

• Conduct a first round of vehicle emissions tests in the winter of 2000.

• Conduct a second round of vehicle emissions tests in the winter of 2001 and compare with first round 

results.

• Objectively analyze vehicle performance and emissions data for both fuels, and draw conclusions.

Accomplishments

• A government-industry working group has been established. Industry participants include BPAmoco/

ARCO, Detroit Diesel Corporation, International Truck and Engine Corporation, Cummins Engine 

Company, Ford Motor Company, Engelhard Corporation, Johnson-Matthey, Corning, NGK-Locke, 

and Fleetguard Nelson. Participating government agencies include the U.S. Department of Energy, the 

National Renewable Energy Laboratory, the California Air Resources Board, the California Energy 

Commission, and the South Coast Air Quality Management District. The working group produced an 
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

62

Emissions Test Plan for the first round of vehicle tests.

• A total of 184 vehicles have been selected to participate in the program. To date, the following fleets 

have been retrofitted with catalyzed particle filters: San Diego School District School Buses, ARCO 

Tanker Trucks, Ralphs Grocery Trucks, LA City Refuse Haulers, Los Angeles County MTA Transit 

Buses, and Hertz Equipment Rental Trucks.

• First Round vehicle test results were published in EC-Diesel Technology Validation Program Interim 

Report , SAE Technical Paper 2000-01-1854, authored by Chuck LeTavec, Jim Uihlein, and Jack 

Segal of ARCO Products Company and Keith Vertin of the National Renewable Energy Laboratory. 

The interim report was presented at the SAE 2000 Spring Fuels and Lubricants Conference and the 

SAE 2000 Government and Industry Meeting.

Future Directions

• Data collected from the grocery truck fleet will be analyzed in detail and a series of technical papers 

will be prepared to document vehicle performance, emissions, and the fleet operating experience.

• A second round of emissions tests will be conducted in the winter of 2001. The second round of 

testing will examine possible performance or emissions deterioration, and will include characterization 

of regulated and unregulated exhaust emissions.

Introduction

BP Amoco (formerly ARCO) has recently 

developed a new diesel fuel called Emission Control 

Diesel (EC-D). EC-D is produced from typical crude 

oil using a conventional refining process. EC-D has a 

maximum sulfur content of 15 ppm, less than 10% 

aromatics by volume, and a nominal cetane number 

of 60. BP Amoco has intentions to make ultra-low 

sulfur diesel fuel widely available in Southern 

California.

Previous studies in the engine laboratory have 

shown that catalyzed particle filters operate more 

efficiently as diesel fuel sulfur content decreases 

[1,2,3]. Ultra-low sulfur fuels lower the exhaust gas 

temperature required to burn particulate matter 

collected on the filter. Ultra-low sulfur fuels expand 

the exhaust gas temperature window needed for filter 

regeneration, thereby improving particulate matter 

conversion efficiency over a wider range of engine 

operating conditions.

A one-year technology validation program is 

being run to evaluate EC-D and catalyzed particulate 

filters using diesel vehicles operating in Southern 

California. The fuel’s performance, impact on engine 

durability and vehicle performance, and emission 

characteristics are being evaluated in several fleets in 

various vocations.

Approach

Eight vehicle fleets are being evaluated in 

Southern California. All vehicles are equipped with 

modern electronically-controlled diesel engines. 

Each fleet contains unmodified vehicles fueled with 

a typical California (CARB) diesel fuel, hereafter 

referred to as control vehicles. For each fleet, a 

select number of vehicles were retrofitted with either 

the Engelhard catalytic soot filter (hereafter 

Figure 1. Tanker Truck Testing on the West Virginia 

University Transportable Chassis 

Dynamometer and Emissions Laboratory
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

63

designated DPXTM), or the Johnson-Matthey 

continuously regenerating technology (hereafter 

designated CRTTM). Both DPX and CRT filters are 

passive devices that were simply installed in place of 

the existing muffler system, without any 

modification to the engines. The retrofitted vehicles 

are fueled exclusively with EC-D fuel using 

segregated fuel storage tanks. 

Each fleet participating in the program contains a 

number of vehicles that are nominally identical 

(same model year, engine, chassis configuration, and 

equipment) except for the exhaust system which may 

have been retrofitted with DPX or CRT filter. 

A subset of vehicles from each fleet was selected 

for emissions testing. The vehicles were tested 

using the West Virginia University transportable 

emissions laboratory. The transportable laboratory 

consists of a heavy-duty chassis dynamometer and an 

emissions measurement laboratory (Figure 1). 

Emissions of carbon monoxide (CO), nitrogen oxides 

(NOx), total hydrocarbons (HC) and particulate 

matter (PM) were measured over the City-Suburban 

Heavy Vehicle Route driving schedule.

Results

Vehicles retrofitted with catalyzed particle filters 

and fueled with EC-D emitted 91% to 99% less 

particulate matter compared to the California dieselfueled vehicles having no exhaust filter equipment. 

Hydrocarbon and carbon monoxide emissions were 

also significantly reduced. Average exhaust 

emissions results for the grocery trucks are compared 

in Figure 2.

For several vehicles retrofitted with catalyzed 

particle filters, particulate matter and hydrocarbon 

emissions were equal to or less than background 

levels sampled at the test site.

Test vehicles equipped with the catalyzed 

particle filters and fueled with EC-D fuel have 

operated reliably during the program start-up period. 

No significant maintenance issues have been 

reported for fleets that have been operating for over 

six months. A more detailed report of fleet operating 

experience will be published when the program is 

completed.

Conclusions

Several types of heavy vehicles have been 

successfully retrofitted with catalyzed particle filters. 

First round tests revealed that retrofitted vehicles 

fueled with EC-D reduced particulate matter, carbon 

monoxide, and hydrocarbon emissions by more than 

90% compared to CARB-fueled vehicles without 

emission control devices.

List of References

1. U.S. Department of Energy, Engine 

Manufacturers Association, and Manufacturers 

of Emission Controls Association, "Diesel 

Emission Control- Sulfur Effects (DECSE) 

Program, Phase I Interim Data Report No. 4: 

Diesel Particulate Filters Final Report", http://

www.ott.doe.gov/decse, Jan. 2000.

2. Warren, J., Allansson, R., Hawer, P., Wilkins, A., 

"Effects on After-treatment on Particulate Matter 

when using the Continuously Regenerative Trap 

(CRTTM)", IMechE Technical Paper S491/006/

98, 1998.

3. Cooper, B., Thoss, J., "Role of NO in Diesel 

Particulate Control", SAE Technical Paper 

890404, 1989.

List of Publications

1. LeTavec, C., Uilein, J., Segal, J., and Vertin, K., 

"EC-Diesel Technology Validation Program 

Interim Report", SAE Technical Paper 2000-01-

1854, 2000.

Figure 2. Average Grocery Truck Emissions over the 

City-Suburban Heavy Vehicle Route
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

64

List of Presentations

1. LeTavec, C., Segal, J., and Uihlein, J., "ECDiesel Technology Validation Program", 

presented at the 2000 SAE Fuels and Lubricants 

Meeting, June 19-22, 2000.

2. Vertin, K., "EC-Diesel Technology Validation 

Program", presented at the 2000 SAE 

Government/Industry Meeting, June 21-22, 

2000.

List of Acronyms

CARB fuel Fuel meeting California Air 

Resources Board quality standards

CO Carbon monoxide

CRT Johnson-Matthey trademark for 

Continuously Regenerating 

Technology filters

DPX Engelhard trademark for catalytic 

soot filters

EC-D EC-Diesel fuel

HC Total hydrocarbons

NOx Oxides of nitrogen

PM Particulate matter

ppm Parts per million

SAE Society of Automotive Engineers
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

65

F. Systems Emission Reduction (SER) Analysis for Automobiles, Light Trucks, 

and Heavy-duty Engines

Wendy Clark (primary contact), Keith Vertin, Keith Wipke, Matthew Thornton

National Renewable Energy Laboratory

1617 Cole Boulevard

Golden, CO 80401

(303) 275-4468, fax: (303) 275-4415, e-mail: wendy_clark@nrel.gov

DOE Program Manager: John Garbak

(202) 586-1723, fax: (202) 586-9811, e-mail: john.garbak@ee.doe.gov

DOE Program Manager: Bob Kost

(202) 586-2334, fax: (202) 586-6109, e-mail: robert.kost@ee.doe.gov

DOE Program Manager: Stephen J. Goguen

(202) 586-8044, fax: (202) 586-1600, stephen.goguen@ee.doe.gov

Subcontractor: Battelle Memorial Institute, Columbus, OH

This Project addresses the following OTT R&D Plan Barriers and Tasks:

Barriers

A. Fuel Property Effects on Engine Emissions and Efficiency

B. Fuel Property Effects on Exhaust Emission Control System Technology

C. Emission Control System Degradation

Tasks

4. Develop Empirical Relationships

Objectives

• Collect final data sets from the Diesel Emission Control Sulfur Effects (DECSE) project and other 

DOE projects, and develop empirical relationships linking emissions to fuels properties.

• Develop and use systems level analysis tools that incorporate the empirical emission relationships to 

identify the best pathways for achieving the technical targets for compression ignition direct injection 

(CIDI) engines, identified in the Advanced Petroleum-Based Fuels (APBF) Multiyear Program Plan.

• Make data and empirical relationships available to DOE research partners.

Approach

• Define the SER framework to augment ADVISOR with new component modules (e.g., emission 

control devices) and laboratory data.

• Develop empirical data relationships on sulfur effects, initially making use of data and analyses from 

the DECSE project.

• Provide a sample pathway analysis for one type of vehicle and configuration, for each of the three 

platforms.

• Recommend future analyses and continue to expand input databases, to identify gaps in the data 

required for valid predictions; use as a guide to develop future R&D programs.
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

66

Accomplishments

• Data collection to define empirical relationships for the fuel sulfur effect on NOx Adsorber, Lean NOx, 

and Diesel Oxidation catalysts is 95% complete.

• Empirical relationships have been developed for fuel sulfur effects on Diesel Particulate Filters.

• Vehicle types/configuration for sample analysis have been identified.

Future Directions

• Finalize fuel sulfur effects empirical data relationships.

• Identify and collect relevant data already existing from research partners.

• Develop protocols for future engine emissions lab data collection/transmission.

• Establish SER analysis approach by analyzing data and developing maps and modules for ADVISOR.

• Perform sample emission reduction pathway analysis for three platforms.

Introduction

The APBF program seeks to identify and 

establish the ability of advanced petroleum fuels and 

non-petroleum fuel blending components to enable 

light-duty CIDI vehicles and heavy-duty CIDI 

engines to meet projected emission standards, while 

continuing to improve engine efficiency and 

durability. 

A component of the APBF program is 

establishing an SER framework for automotive, light 

truck and heavy-duty engine applications. This 

framework is focused on applying a systems 

approach to analyzing system emissions reduction 

pathways and fuel options. Establishing the SER 

modeling approach requires analysis of available 

data, and development of maps and modules to add 

to the existing ADVISOR system model. 

Activities have been initiated to collect available 

fuels and emissions data, and to develop the 

databases from which maps and analysis modules 

can be generated. Efforts to develop the sample 

pathway analysis for passenger car, light truck and 

heavy-duty engine applications are underway.

Approach

The SER model will be implemented in 

ADVISOR, which involves developing and adding 

modules and empirical relationships to the existing 

software package. In the first year of this multi-year 

effort, development of the capability to analyze fuel 

effects within a system context began. A fuel 

property database was established, incorporating fuel 

property data from a number of projects and sources, 

and including links to the existing heavy-duty chassis 

emission database. Data from the effects of fuel 

sulfur on emissions, investigated in the DECSE 

project, are being used to develop empirical 

relationships. Collection of fuel and emissions data is 

the initial step in working to develop modules and 

empirical relationships for the SER model. Other 

tasks underway include:

• Outlining how data from research partners are 

included, and defining the preferred and 

minimum protocols for collecting engine 

laboratory data,

• Outlining how the "research pathway analysis" 

will be completed,

• Collecting data from participating research 

partners including other national labs, and

• Completing a sample pathway analysis for two 

of the applications of interest.

Results

A collection of information is needed to 

investigate SER pathways. Table 1 identifies the 

three systems of interest and types of information 

necessary to enable pathway analysis to be 

completed. Technical targets for NOx and particulate 
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

67

matter are identified and projects representing 

sources for emissions data are included.

Fuel property data have been collected from a 

number of sources including the DECSE project, and 

the Ad Hoc fuels evaluation project. These data have 

been incorporated into a database, which has a webbased interface to enable users to do queries of fuel 

properties. 

Empirical data relationships between fuels and 

emissions have been developed based on evaluations 

conducted in the DECSE project. Analysis of these 

data provided insight into the general fuel sulfur 

level effects on PM and NOx emissions from several 

exhaust emission control devices. The diesel 

particulate filter (DPF) and NOx adsorber were tested 

and analyzed for their effectiveness in controlling 

PM and NOx respectively. Both technologies were 

shown to be effective in emissions control, but were 

also sensitive to fuel sulfur levels. As an example, 

the NOx adsorber conversion efficiency as a function 

of fuel sulfur level and inlet temperature is shown in 

Figure 1.

Additional empirical data relationships will be 

developed in the future as data are generated from 

APBF-DEC projects and other future projects. Table 

2 summarizes some of the available DECSE data that 

are being evaluated for use in developing empirical 

data relationships. The empirical relationships, as 

well as the fuel and emission data, are being used to 

develop modules to be added in the existing 

ADVISOR model.

Conclusions

Progress has been made on developing 

components necessary to enable a system level 

analysis of the emissions pathways for advanced 

engines and vehicles. A sample pathway analysis for 

two of the platforms has been completed and it is 

anticipated that a refined pathway analysis for all 

platforms will be in place by the end of FY 2001. 

Fuel and emissions data from testing engines, 

vehicles and advanced emission control devices are 

being transformed into modules and submodels that 

form the building blocks of the SER model. This 

model will provide the capability to predict potential 

emissions and efficiency improvements for 

automobiles, light-trucks and heavy-duty engines. 

List of Acronyms

ADVISOR Advanced Vehicle Simulator

APBF Advanced Petroleum-Based Fuels

APBF-DEC Advanced Petroleum-Based FuelsDiesel Emission Control

CIDI compression ignition direct injection

DECSE Diesel Emission Control - Sulfur 

Effects program

DPF diesel particulate filter

DVECSE Diesel Vehicle Emission Control - 

Sulfur Effects

EGR exhaust gas recirculation

EUI electronic unit injector

HEUI high pressure electronic unit injector

HSDI high speed direct injection

NOx nitrogen oxides

PM particulate matter

SER Systems Emissions Reduction

Figure 1. Comparison of NOx conversion efficiency 

before and after desulfurization for catalysts 

aged with 3, 16, and 30 ppm sulfur level fuels 

for 250, 200, and 150 hours respectively
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

68

Vehicle Systems Advanced Automobile (80 mpg) Light-Duty Truck Heavy-Duty Truck Engine

Engines Various-1.7, 1.9, 2.2 liter HSDI’s with 

Common Rail Injection

Navistar 7.3 liter 

T444/Powerstroke with HEUI

Cummins 11 liter ISM with EUI

NOx Reduction

Target: 0.05 g/mile

Research: DECSE/FEV NOx

Adsorbers, SwRI and Automaker 

Fuels and Engine Optimization Study, 

ORNL DVECSE, previously 

published EGR strategies

Target: 0.05 g/mile

Research: DECSE/lean-NOx

catalyst, SwRI and Automaker 

Fuels and Engine Optimization 

Study, previously published EGR 

strategies, data from Ricardo/

International study

Target: 1 g/bhp-hr

Research: DECSE/lean-NOx

catalyst, previously published EGR 

strategies

PM Reduction

Target: 0.01 g/mile

Research: SwRI and Automaker Fuels 

and Engine Optimization Study, 

ORNL DVECSE, Ad-Hoc 

(Oxygenates and PM), previously 

published diesel particulate filter data

Target: 0.01 g/mile

Research: DECSE/oxidation 

catalyst, Ad-Hoc (Oxygenates and 

PM), previously published diesel 

particulate filter data

Target: 0.0125 g/bhp-hr

Research: DECSE/oxidation 

catalyst, EC-Diesel and DPF 

evaluation, Ad-Hoc (Oxygenates 

and PM), previously published 

diesel particulate filter data

Table 1. Systems of Interest in Systems Emission Reduction Pathways

Table 2. Example DECSE Data being Incorporated into SER
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

69

IV. HEALTH & SAFETY, MATERIALS COMPATIBILITY, 

ECONOMICS, AND DISSEMINATION

A. Environmental Performance of Oxygenated Fuel Compounds Used in 

Advanced Petroleum-Based Fuels

David Layton (primary contact), Alfredo A. Marchetti, Jeffrey Daniels

Lawrence Livermore National Laboratory

Health and Ecological Assessment Division

PO Box 808

Livermore, CA 94551

(925) 422-0918, fax: (925) 423-6785, e-mail: layton1@llnl.gov

DOE Program Manager: John Garbak

(202) 586-1723, fax: (202) 586-9811, e-mail: john.garbak@ee.doe.gov

This Project addresses the following OTT R&D Plan Barriers and Tasks:

Barriers

H. Health, Safety, and Regulatory

Tasks

8. Safety, Health, and Consumer Acceptance Aspects of Liquid Fuels

Objectives

• Develop a systematic methodology to assess the environmental impact of oxygenated fuel compounds 

for use in advanced petroleum-based fuels in order to reduce particulate emissions from CIDI engines.

• Evaluate the nature and magnitude of potential human exposures to oxygenates released to the 

environment.

• Apply the environmental assessment techniques to the oxygenate dimethoxy methane (DMM) and 

compare its predicted environmental performance with other fuel compounds. 

Approach

• Identify and implement environmental transport and fate models for use in conducting assessments of 

the behavior of fuel oxygenates in regional landscapes, soils, ground water, surface water, etc.

• Compile and review data on the physicochemical properties of DMM and determine the potential for 

its degradation in the environment.

• Calculate relevant environmental transport properties using available software and/or models to fill 

information gaps and for quality assurance.

• Implement and run screening-level models to determine the fate of DMM and reference fuel 

compounds for various environmental release scenarios associated with its life cycle.

• Predict human exposures via ingestion, inhalation, and dermal uptake. 
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

70

Accomplishments

• Selected and implemented environmental models suitable for conducting screening-level analyses of 

fuel oxygenates.

• Researched, installed, and tested software for property estimation, including biodegradation 

prediction.

• Simulated the transport and fate of DMM and other reference fuel compounds in environmental media.

• Evaluated potential water-based human exposures to water contaminated with DMM.

Future Directions

• Evaluate property-estimation models and software for selected physicochemical parameters (e.g., 

Henry’s law constant, solubility in water, partition coefficients, etc.) and environmental transformation 

processes (e.g., hydrolysis, biodegradation, hydroxyl radical oxidation, etc.) with benchmark fuel 

components, such as benzene, MTBE, and isooctane.

• Define environmental parameters for screening models that reflect a range of site-specific conditions.

• Conduct screening-level assessments of diesel fuel oxygenates.

• Carry out selected experiments to verify predictions and/or fill key data gaps for oxygenates of 

interest. 

Introduction

Research conducted in recent years has 

demonstrated that the addition of oxygen-bearing 

compounds to diesel fuels reduces particulate 

emissions. While there are potentially many 

compounds that could be used to add oxygen to fuel, 

some compounds may have undesirable 

environmental impacts, for example, contamination 

of ground water from leaking underground fuel 

tanks. This project, therefore, aims to establish a 

methodology to assess the potential environmental 

impacts of oxygenated fuel compounds. Assessments 

and supporting data developed by the project will 

assist DOE/OTT and industrial partners to evaluate 

the nature and magnitude of the environmental 

impacts of fuel oxygenates. 

Approach

The assessment of a given fuel compound begins 

with the characterization of its key physicochemical 

properties. Next, we conduct screening-level 

analyses to predict the likely environmental fate(s) of 

the compound when released into reference 

landscapes. Potential inhalation, ingestion, and 

dermal exposure pathways are addressed as well. 

Information on the toxicity of the compound is then 

evaluated. In turn, we identify key data gaps, specify 

the kinds of studies needed to obtain the necessary 

data, and evaluate any special methodological issues 

related to the assessment of the fuel oxygenate. The 

fuel compound that we have addressed initially using 

this methodology is DMM. For purpose of 

comparison, we also show the results of applying 

these models to other typical fuel components.

Results

Our analysis of the physicochemical properties 

of DMM indicates that its tendency to partition to 

water is actually greater than that of MTBE, 

suggesting that its environmental transport will 

depend in part on the movement of water in an 

environmental compartment. In the atmosphere, 

DMM will be degraded mainly by OH oxidation, 

with a half-life of about 2 days. By comparison, 

DMM is not predicted to biodegrade quickly in 

ground water. Model predictions based on chemicalstructure relationships, for example, indicate that 

DMM will not biotransform readily (see Figure 1). 

The predictions are in agreement with experimental 

data that showed DMM to be recalcitrant. This fact 

and its high solubility in water are preliminary 

indications that DMM would behave like MTBE in 
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

71

the environment to the detriment of ground water 

resources.

We used an equilibrium model to determine the 

partitioning of DMM between the air, water, and 

solid phases of a reference soil (see Figure 2, MTBE 

and benzene also included). DMM favors the soil 

water phase by 98%. We also simulated the transport 

of DMM, MTBE and benzene from a uniformly 

contaminated 30-cm surface-soil layer to a ground 

water well located 50 m down gradient from the 

source region by using a vadose-zone transport 

model linked to a 3D groundwater transport model. 

As seen in Figure 3, DMM and MTBE 

concentrations peak at around the same time in the 

well water. Benzene concentrations in the well water 

peaks at an earlier time due to its more rapid 

transport in soil, but its predicted concentration is 

significantly diminished by biodegradation. 

We then estimated human exposure to water 

containing 1 ppm of DMM, MTBE, and benzene (see 

Figure 4). The main routes of exposure to DMM are 

inhalation and ingestion; dermal uptake is negligible 

due to its relatively low octanol-water partition 

coefficient. The overall exposure is similar to that of 

MTBE and about half that of benzene.

Conclusions

Previous work conducted on DMM indicates that 

its use as a diesel-fuel oxygenate would be limited 

because its high vapor pressure would require fuelsystem modifications. Nevertheless, we have also 

shown that high vapor pressure is not the only 

Figure 1. Biodegradation potential for DMM and other 

fuel compounds. A value above 0.5 indicates 

rapid biodegradation.

Figure 2. Partitioning of DMM and other fuel 

compounds in soil.

Figure 3. Time-varying concentrations of DMM, MTBE, 

and benzene predicted in a well downgradient 

from a contaminated surface soil.

Figure 4. Water-based exposures to DMM, MTBE, and 

benzene in drinking water.
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

72

undesirable property of DMM. It is likely to be 

recalcitrant and mobile in ground water, behaving 

similarly to MTBE in the environment. Our 

evaluation of available property-prediction software 

indicates that most of the key physicochemical 

parameters required for transport modeling can be 

estimated from chemical structure information. 

However, such estimates are best used for 

comparative, screening-level analyses of fuel 

oxygenates. Experiments will be needed to refine 

property estimates, and importantly, define 

temperature-dependent relationships.

List of Presentations

1. David W. Layton, William J. Pitz, Jeffrey I. 

Daniels, Steve Carle, Reed M. Maxwell, and Ken 

L. Carroll, "Dimethoxy Methane as a Potential 

Oxygenate for Diesel Fuel: Preliminary 

Assessment of its Environmental Behavior", 

presented at the American Chemical Society 

219th National Meeting & Exposition, March, 

2000.

2. David W. Layton, Alfredo A. Marchetti, and 

Jeffrey I. Daniels, "Life Cycle Assessments of 

Fuels for Advanced Engines: Oxygenate 

Assessment", Office of Transportation 

Technologies Annual Review, Argonne National 

Laboratory, May, 2000.

List of Acronyms

3D Three-dimensional

DMM Dimethoxy methane

DOE US Department of Energy

MTBE Methyl tert-butyl ether

OH Hydroxyl radical

OTT Office of Transportation 

Technologies

ppm Part per million
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

73

B. Chemical Characterization of Toxicologically Relevant Compounds From 

Diesel Emissions

Edwin A. Frame (primary contact), Douglas M. Yost

Southwest Research Institute

6220 Culebra Road 

San Antonio, TX 78238-5166

(210) 522-2515, fax: (210) 522-3270, e-mail: eframe@swri.edu

DOE Program Manager: John Garbak

(202) 586-1723, fax: (202) 586-9811, e-mail: john.garbak@ee.doe.gov

Industry Co-Leads: James Ball (Ford), Charles Lapin (Consultant)

This Project addresses the following OTT R&D Plan Barriers and Tasks:

Barriers

E. Toxic Emissions

F. Ultra-fine Particles

Tasks

8. Safety, Health, and Consumer Acceptance Aspects of Liquid Fuels

Objectives

• Investigate the role of fuels on the engine-out exhaust emissions of potentially toxicologically relevant 

compounds.

• Determine polycyclic aromatic hydrocarbon (PAH) content of organic solvent extracts of exhaust 

particulate matter; gaseous exhaust PAH; other gaseous exhaust "toxics" collected from a diesel engine 

using various fuel compositions.

Approach

• A DaimlerChrysler OM611 CIDI engine was used to determine the effect of diesel fuel type on 

toxicologically relevant compounds from engine-out exhaust emissions.

• The engine was controlled by a SwRI Rapid Prototyping Electronic Control System (RPECS).

• The test matrix included 5 fuels (including one oxygenate blend) operated over 5 speed/load points.

• Each speed/load point was devised to hold location of Peak Pressure (LPP) of combustion at 7oATDC, 

while maintaining cylinder balance within 5% of the Indicated Mean Effective Pressure (IMEP), with 

pilot fuel injection disabled.

• Two of the speed/load points were operated at two different pilot fuel injection strategies. One pilot 

strategy used the stock controller, while the other was to include pilot fuel injection while maintaining 

the Location of Peak Pressure at a constant.

• Four gaseous "toxic" exhaust emissions were measured.

• Eleven gaseous PAH compounds were measured.

• Seventeen PAH compounds were determined from the soluble organic fraction of the exhaust 

particulate matter.
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

74

Accomplishments

• All fuel tests completed in triplicate for five modes, pilot injection off, LPP operation. Pilot fuel 

injection effect evaluation for all fuels completed in triplicate for two modes and two pilot fuel 

injection strategies.

• Statistically significant fuel effects on exhaust emissions identified.

• Oxygenate-containing fuel and Fischer-Tropsch fuel produced the lowest overall toxic gas and PAH 

exhaust emissions.

 Future Directions

• In a follow-on phase, similar investigations will be conducted using an engine with exhaust emission 

control devices.

Introduction

This program is part of an overall study that 

examines the effects of alternative diesel fuels 

including one oxygenated compound 

(dimethoxymethane) in diesel fuel on the emissions 

of particulate matter, oxides of nitrogen, and fuel 

economy. This program addressed the chemical 

characterization of engine-out emissions of 

compounds with known or suspected toxicological 

properties (e.g. carcinogens).

Objective

The goal of this project was to better understand 

the role of fuels on the emissions of a subset of 

potentially toxicologically relevant compounds. 

Objectives of this program were: 1) to measure the 

polycyclic aromatic hydrocarbon (PAH) content of 

organic solvent extracts of particles collected from 

CIDI engines under a matrix of engine and fuel 

conditions, 2) to measure the gas-phase polycyclic 

aromatic hydrocarbons from this engine and, 3) to 

measure formaldehyde, acetaldehyde, benzene, and 

1,3-butadiene using the same conditions that are used 

to collect particles. These measurements were made 

on engine-out emissions. 

Approach

A standard set of polycyclic aromatic 

hydrocarbons (PAH) in organic solvent extracts of 

diesel particles and from the gas phase of diesel 

emissions were measured in this program. In 

addition, four toxic air pollutants (as noted above) 

were quantified. The OM611 CIDI engine was run at 

five different engine speeds and loads and controlled 

to hold location of peak pressure of combustion at 

7o

ATDC. Individual cylinder balance was 

maintained within 5% of the Indicated Mean 

Effective Pressure (IMEP), with pilot fuel injection 

disabled. The engine was also controlled at two 

speed and load combinations using two different 

pilot injection control strategies. Particulate filter 

samples were collected at each load and control 

condition. The engine operating conditions are 

shown in Table 1.

The four toxic air pollutants from mobile sources 

cited in the Clean Air Act (formaldehyde, 

acetaldehyde, benzene, and 1,3-butadiene) were 

measured in triplicate at each of the points discussed 

above. The five test fuels, along with selected fuel 

properties are shown in Table 2.

The particulate matter was sampled from a 

203mm-dilution tunnel using carbon dioxide tracer 

for determining dilution ratio. A polyurethane foam 

and XAD-2 resin trap were utilized for sampling gas 

phase PAH compounds. Soluble phase PAH 

compounds were extracted from 90 mm filters. 

Mode RPM BMEP, bar % EGR

M 12 900 0.10 40

M 11 1500 2.62 30

M 10 2000 2.00 30

M 6 2300 4.20 15

M 5 2600 8.80 5

Table 1. OM 611 Engine Operating Conditions
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

75

Benzene and 1,3-Butadiene were collected in a 

sample bag from the dilution tunnel sample zone. 

Formaldehyde and Acetaldehyde were trapped on a 

DNPH adsorbent cartridge from the dilution tunnel 

sample zone.

Discussion

Fuel comparisons utilizing the Ad-Hoc Fuels 

Group Mode Weighting Factors shown in Table 3 

were made for brake specific exhaust emissions with 

the engine operated under LPP control with pilot fuel 

injection turned off.

Fuel (Code) H, wt % C, wt % O, wt % Cetane 

Number Sulfur, ppm Aromatics, wt %

California Reference Diesel Fuel (CA) 13.4 86.4 0.2 45 176 18.9

Low-Sulfur Diesel Fuel (ALS) 14.4 85.6 0.0 63 1 9.0

Fischer-Tropsch Diesel (FT-100) 15.1 84.8 0.1 84 0 0.2

Oxygenate Blend: 15% Dimethyoxymethane in ALS (ADMM15) 13.7 81.6 4.7 59 < 2 8.2

EPA 2D Certification Fuel (DF-2) 13.0 86.7 0.3 44 337 30.3

Table 2. Toxicity Test Fuels

Mode Mode Weights, seconds

Mode 11 600

Mode 10 375

Mode 6 200

Mode 5 25

Total 1,200

Table 3. Weighting Factors for Engine-Out Emissions

Rank HC CO PM SOF NOx CO2

Highest

Lowest

DF-2 DF-2 DF-2 DF-2 DF-2 ADMM15

CA CA CA CA ADMM15 DF-2

ALS ALS ALS ALS FT-100 CA

ADMM15 ADMM15 ADMM15 ADMM15 CA ALS

FT-100 FT-100 FT-100 FT-100 ALS FT-100

Table 4. Fuel Rank Order from ANOVA for Weighted Average Regulated Mass Emissions for LPP Operation with Pilot 

Fuel Injection Turned Off

Figure 1. Test Fuel Hydrocarbon Weighted Average 

Mass Emissions (g/kWh)

Figure 2. Test Fuel Weighed Average Particulate Matter 

Mass Emissions (g/kWh)
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

76

Several statistically significant trends, at 95% 

confidence, were apparent from an ANOVA of the 

weighted average brake specific emissions data. 

Table 4 summarizes the qualitative general rank 

order for the regulated weighted average mass 

emissions during LPP engine operation with pilot 

fuel injection turned off. For HC, CO, PM, and SOF 

the lowest emitting fuels were ADMM15 and FT100, with the higher emitting fuels being DF-2 then 

CA. Figure 1 shows the relative levels of test fuel 

hydrocarbon emissions with statistically similar 

groupings shown with horizontal bars. The statistical 

groupings and relative levels of particulate matter 

emissions are shown in Figure 2 for the test fuels. 

The relative SOF levels of the particulate matter and 

their statistical groups are represented in Figure 3. 

The highest NOx emitter was DF-2, followed jointly 

by ADMM15, FT-100, and CA, with ALS being the 

lowest NOx emitting fuel.

Table 5 is the qualitative ranking of the test fuels 

for the four EPA Clean Air Act toxic compounds. 

Figure 4 shows the ranking and statistically 

significant similar groupings (horizontal bars) for 

Rank Benzene 1,3 Butadiene Formaldehyde Acetaldehyde

Highest

Lowest

CA CA DF-2 DF-2

DF-2 DF-2 ALS ALS

ALS ALS CA CA

FT-100 ADMM15 ADMM15 ADMM15

ADMM15 FT-100 FT-100 FT-100

Table 5. Fuel Rank Order from ANOVA for Weighted Average Air Toxic Mass Emissions for LPP Operation with Pilot 

Fuel Injection Turned Off

Figure 3. Test Fuel Weighted Average Soluble Organic 

Fraction Mass Emissions (g/kWh)

Figure 4. Test Fuel Weighted Average Benzene 

Emissions (mg/kWh)

Figure 5. Test Fuel Weighted Average 1,3-Butadiene 

Emissions (mg/kWh)

Figure 6. Test Fuel Weighted Average Formaldehyde 

Emissions (mg/kWh)
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

77

benzene emissions. For 1,3-butadiene the lowest 

emitting fuels were FT-100 and ADMM15, then 

ALS, with the highest emitting fuels being DF-2 and 

CA; the statistical groupings are shown in Figure 5. 

The highest formaldehyde and acetaldehyde emitter 

was DF-2, followed by ALS, CA, then jointly by 

ADMM15 and FT-100. Figure 6 shows the relative 

levels and statistical groupings for formaldehyde. 

The corresponding groupings for acetaldehyde are 

shown in Figure 7. For the EPA air toxic 

compounds, ADMM15 and FT-100 were statistically 

similar emitting fuels, and always in the lowest 

grouping for LPP operation with pilot fuel injection 

turned off.

The fuel rankings for thirteen of the particulate 

bound soluble phase PAH compounds are shown in 

Table 6. Due to non-detects, four PAH compounds 

are being analyzed again with a higher-resolution 

instrument. The four compounds being reanalyzed 

Rank Naphthalene Acenapthylene Acenapthene Fluorine Phenanthrene

Highest

Lowest

DF-2 CA DF-2 DF-2 DF-2

CA DF-2 CA CA CA

FT-100 FT-100 FT-100 ADMM15 FT-100

ADMM15 ADMM15 ADMM15 FT-100 ALS

ALS ALS ALS ALS ADMM15

Rank Anthracene Fluoranthene Pyrene Benzo(a)anthracene Chrysene

Highest

Lowest

DF-2 DF-2 DF-2 DF-2 DF-2

CA ALS ALS CA CA

FT-100 CA CA ALS ALS

ADMM15 FT-100 FT-100 FT-100 FT-100

ALS ADMM15 ADMM15 ADMM15 ADMM15

Rank Benzo(b)fluoranthene Benzo(k)fluoranthene Benzo(e)pyrene

Highest

Lowest

DF-2 DF-2 DF-2

ALS CA CA

CA ALS ALS

ADMM15 ADMM15 FT-100

FT-100 FT-100 ADMM15

Table 6. Fuel Rank Order from ANOVA for Weighted Average Particulate Matter PAH Mass Emissions for LPP 

Operation with Pilot Fuel Injection Turned Off

Figure 7. Test Fuel Weighted Average Acetaldehyde 

Emissions (mg/kWh)

Figure 8. Test Fuel Weighted Average Particulate Phase 

Naphthalene Emissions (μg/kWh)
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

78

are benzo(a)pyrene, indeno(123-cd)pyrene, 

dibenzo(a-h)anthracene, and benzo(ghi)perylene. 

Figure 8 shows the statistical groupings for the PAH 

naphthalene bound to the particulate matter. Figure 9 

is the statistical groupings for the particulate phase 

PAH chrysene. The emissions of particulate bound 

PAH benzo(e)pyrene are shown in Figure 10, along 

with the statistical groupings. For the majority of 

PAH compounds, DF-2 fuel was statistically 

different from the other test fuels. The ADMM15 

and FT-100 fuels were in the statistically equivalent 

(95% confidence) lowest grouping for particulate 

bound PAH compounds.

The gas phase PAH emissions rank the test fuels 

qualitatively in the general order shown in Table 7. 

The gas phase PAH naphthalene mass emissions are 

shown in Figure 11 along with the statistical 

groupings. In general, the other gas phase PAH 

compounds had statistical groupings similar to 

naphthalene.

Statistical groupings for engine control strategy, 

which includes pilot fuel injection effects, from an 

ANOVA for modes 10 and 11 are shown in Figure 12 

for particulate matter emissions and in Figure 13 for 

NOx emissions. For the least square means of the 

combined modal and fuel data, each engine control 

approach was statistically unique for PM and NOx. 

The air toxic benzene response in Figure 14 indicates 

the two pilot conditions are statistically similar, but 

different from LPP operation with pilot turned off. 

The LPP with pilot off was statistically the lowest 

control strategy for the four air toxic emissions. The 

Rank Naphthalene 2-Methylnapthalene 1-Methylnaphthalene 2,6-Dimethylnaphthalene

Acenaphthylene

Highest

Lowest

CA DF-2 DF-2 DF-2 DF-2

DF-2 CA CA CA ALS

ALS ALS ALS ALS CA

ADMM15 ADMM15 ADMM15 ADMM15 ADMM15

FT-100 FT-100 FT-100 FT-100 FT-100

Rank Acenapthene Fluorene Phenanthrene Anthracene Fluoranthene Pyrene

Highest

Lowest

DF-2 DF-2 DF-2 DF-2 DF-2 DF-2

CA CA CA CA CA CA

ALS ALS ALS ALS ALS ALS

ADMM15 FT-100 FT-100 ADMM15 ADMM15 FT-100

FT-100 ADMM15 ADMM15 FT-100 FT-100 ADMM15

Table 7. Fuel Rank Order from ANOVA for Weighted Average Gas Phase PAH Mass Emissions for LPP Operation with 

Pilot Fuel Injection Turned Off

Figure 9. Test Fuel Weighted Average Particulate Phase 

Chrysene Emissions (μg/kWh)

Figure 10. Test Fuel Weighted Average Particulate Phase 

Benzo(e)pyrene Emissions (μg/kWh)
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

79

particulate bound PAH chrysene emissions in Figure 

15 show pilot operation to be different from LPP 

operation. The same statistical conclusion could be 

made for the other particulate PAH compounds. The 

effect of pilot fuel injection on exhaust emissions, 

compared to the LPP operation with pilot turned off, 

can be summarized as follows:

• PM emissions increase with pilot fuel injection;

• NOx emissions decrease with pilot fuel injection;

• Gaseous air toxic levels increase with pilot fuel 

injection; and

Figure 11. Test Fuel Weighted Average Gaseous Phase 

Naphthalene Emissions (μg/kWh)

Figure 12. Effect of Pilot Fuel Injection on PM Emissions 

(g/kWh)

Figure 13. Effect of Pilot Injection on NOx Emissions (g/

kWh)

Figure 14. Pilot Fuel Injection Effect on Air Toxic 

Benzene Emissions (mg/kWh)

Figure 15. Pilot Fuel Injection Effect on Particulate PAH 

Chrysene Emissions (μg/kWh)

Figure 16. Test Fuel Least Square Means for Pilot Fuel 

Injection for Particulate PAH Chrysene 

Emissions (μg/kWh)
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

80

• Both soluble and gas phase PAH increase with 

pilot fuel injection.

The fuel rank order, along with the statistical 

groupings for the particulate bound PAH chrysene 

emissions, is shown in Figure 16. The least square 

means are calculated by combining the modal and 

control data. Figure 16 may be compared to Figure 

9, which suggests pilot fuel injection increases the 

PAH chrysene emissions, but the fuel ranking is 

similar. The other particulate bound and gas phase 

PAH compounds revealed fuel ranking and relative 

magnitude results similar to chrysene. The fuel rank 

order for exhaust emissions with pilot fuel injection 

operation can be summarized as follows:

• PM rank for ADMM15 and FT-100 lowest, with 

DF-2 highest;

• NOx rank is FT-100 lowest, ADMM15 middle, 

and DF-2 highest;

• Gaseous air toxic rank is FT-100 and ADMM15 

lowest, with DF-2 highest; and

• Both soluble and gas phase PAH rank is FT-100 

and ADMM15 statistically similar as lowest, 

with DF-2 the highest emitting fuel.

Conclusions

• ADMM15 or FT-100 had the lowest overall 

weighted average emission response of the test 

fuels.

• ADMM15 fuel was statistically the same as FT100 fuel for toxic, PM, and PAH emissions.

• Pilot fuel injection changes the magnitude of the 

emission response, but does not significantly 

alter the fuel rank order.

List of Presentations

1. Yost, D.M. and E.A. Frame, "Particulate Matter 

Analysis from an Advanced Diesel Engine", 

CIDI Engine Combustion, Emission Control, and 

Fuels R & D, Merit Review and Peer Evaluation, 

Argonne National Laboratory, 22-24 May 2000.

List of Acronyms

ADMM15 15% by Volume DMM blended in 

ALS Fuel

ALS Low Sulfur Diesel Fuel

ANOVA Analysis of Variance

ATDC After Top Dead Center

BSFC Brake Specific Fuel Consumption

CA California Reference Diesel Fuel

DF-2 EPA Certification Diesel Fuel

DMM dimethoxymethane

DNPH Dinitrophenylhydrazine

FT-100 Neat Fischer-Tropsch Fuel

IMEP Indicated Mean Effective Pressure

LPP Location of Peak Pressure

NOx Oxides of Nitrogen

PAH Polycyclic Aromatic Hydrocarbon

PM Particulate Matter

RPECS SwRI Rapid Prototyping Electronic 

Control System

SOF Soluble Organic Fraction
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

81

C. Comparing and Contrasting Particle Emissions from Spark Ignition and 

Compression Ignition Engines

Scott Sluder (primary contact), Douglas Blom, John Storey

Oak Ridge National Laboratory

P. O. Box 2009, MS8087

Oak Ridge, TN 37831

(865) 241-9133, fax: (865) 574-2102, e-mail: sluders@ornl.gov

DOE Program Manager: Dr. James Eberhardt

(202) 586-1694, fax:(202) 586-4166, e-mail:james.eberhardt@ee.doe.gov

DOE Program Manager: Mr. Stephen J. Goguen

(202) 586-8044, fax: (202) 586-1600, e-mail: stephen.goguen@ee.doe.gov

Subcontractors: Automotive Testing Laboratories, Inc., East Liberty, Ohio

This Project addresses the following OTT R&D Plan Barriers and Tasks:

Barriers

F. Ultra-fine Particles

Tasks

8. Safety, Health, and Consumer Acceptance Aspects of Liquid Fuels

Objectives

• To document and report the characteristics of particulate matter (PM) emissions for several gasoline 

vehicles in order to help develop a more complete understanding of the need and potential for reducing 

emissions of particulate matter from vehicles, both spark ignition and diesel. By studying the PM 

emissions of past, current, and emerging gasoline vehicles with a level of scrutiny being afforded 

diesel engine exhaust, a more comprehensive and accurate foundation for our environmental and 

energy strategy can be formed.

Approach

• ORNL is assisting in forming a comprehensive database on PM emissions from both compression 

ignition (diesel) and spark ignition engines. Augmenting ongoing studies of PM characteristics and 

health effects, ORNL is engaged in the following efforts:

- Developing historic trends in gasoline vehicle PM data, noting key impacts of fuel changes, and 

determining likely achievable PM emission reductions.

- Application of transmission electron microscopy (TEM) to characterize the morphology of 

exhaust PM.

- Development and application of a new mass-spec instrument to determine the composition of 

individual particles and the compounds adhering to their surface.

Accomplishments

• Tested and documented the PM emissions from a pre-emission-control era gasoline vehicle with 

leaded and unleaded fuel to serve as a historical benchmark.
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

82

• Applied new methods of exhaust particle capture and TEM analysis to compare the morphology of 

gasoline and diesel engine PM.

• Assembled a new mass spectrometry instrument for analysis of the composition of exhaust particle 

surface and core. Real-time aerosol mass spectrometer (RTAMS) has been built and is undergoing 

initial tests.

Future Directions

• Continue to build and report database on gasoline engine PM, including emerging technology direct 

injected gasoline engines, as well as supplementing data on diesel PM.

• Apply TEM and RTAMS to characterize the composition and morphology of exhaust PM in 

unprecedented detail.

Introduction

The feasibility of emerging diesel emissions 

control appears highly dependent on the availability 

of low-sulfur diesel fuel. An analogous situation 

faced the automakers around 1970 where the 

catalytic converter was needed to achieve new 

emissions regulations, yet was incompatible with the 

lead-containing gasoline of the era. History has 

borne out that the availability of unleaded gasoline, 

eventually also with reduced sulfur, was pivotal in 

gasoline cars achieving the remarkably low 

emissions of today. The diesel engine may be at the 

same crossroads, approximately where the gasoline 

engine was before catalysts. To be able to present 

this historic perspective, emissions data from 

gasoline vehicles, with and without their catalysts, 

are being compiled.

Approach

Historical Benchmark. The effort has begun 

with the emissions study of a pre-control era vehicle 

using both leaded and unleaded fuel. A restored 

1967 Chrysler 300 was selected as the pre-control era 

subject. The PM from the vehicle on unleaded fuel 

was quite low, although the gaseous emissions were 

of course alarming by today’s standards. Leaded fuel 

more than doubled the mass of PM (Figure 1). PM 

size distribution via MOUDI showed the dominance 

of particles under 50 nm typical of gasoline engines, 

except in the case of leaded fuel a large population of 

particles appeared at 100 nm (see Storey et. al.).

The next phase of the study will address the 

direct injected gasoline engine, with and without 

aftertreatment.

Analysis by TEM and RTAMS. The Northern 

Front Range Air Quality Study concluded that for the 

Denver metropolitan area during 1996 and 1997, 

55% of PM2.5 was attributable to motor vehicle 

exhaust. It is of vital interest to understand the 

chemistry, morphology, size distribution and 

microstructure of motor vehicle exhaust. Our goal 

was to apply the techniques of TEM and energy 

dispersive X-ray spectroscopy (EDS) to the analysis 

of the microstructure, morphology and 

microchemical composition of particulate matter 

from motor vehicle exhaust. Source sampling from a 

variety of vehicles was conducted. As part of an 

ongoing research project into the health effects of 

motor vehicle particulate matter, Southwest Research 

Institute (SwRI) is performing chassis dynamometer 

tests on a fleet of spark ignition vehicles. PM was 

collected from the following vehicles: 1993 Mercury 

Figure 1. SI PM Emissions from 1967 Chrysler 300
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

83

Sable, 1996 Mazda Millenia, 1998 Honda Accord 

(ULEV), and a 1976 Ford F-150 which produced 

visible black smoke. A range of properties was 

observed among the vehicles under different 

operating conditions. Figures 2 and 3 are highresolution micrographs showing structural 

differences in particulate matter. Figure 2 illustrates 

the "onion peel" microstructure known as 

turbostratic. The planes of carbon atoms are only 

organized in two dimensions and is typical of 

moderate temperature combustion processes. Figure 

3 is an example of a graphitic crystal structure where 

the carbon atoms are well organized in all three 

dimensions. Graphitic microstructures are indicative 

of high combustion temperatures. Additional 

differences in chemical composition have been 

observed among the various samples of PM. 

Electron microscope characterization of particulate 

matter can be a valuable tool in understanding the 

microchemistry, morphology and microstructure at 

an atomic level.

Another feature of exhaust PM that must be 

determined to fully understand the health risks is the 

chemical composition of both the surface as well as 

the core of the particle. The surface, typically laden 

with hydrocarbons, is what actually contacts the 

tissues inside the respiratory system. A new 

instrument, the RTAMS has been built for this 

analysis, and is undergoing initial trials in the ORNL 

engine lab. The instrument as designed will yield 

real-time particle mass spectra as a function of 

particle size from molecular size (<1nm) to well 

above 100 nm. Dilute exhaust gas is sampled 

directly into the RTAMS and the particles charged 

electrostatically. The RTAMS uses the same 

principles for analyzing large molecules using mass 

spectroscopy. Particle size can be discriminated by 

charging the particle at different voltages, or by 

changing the frequency of the ion trap. Once inside 

the ion trap, the particle is ionized with an ultra-fast 

burst of laser energy. 

The optimal working range of the spectrometer is 

expected to be below 20 nm where only a single 

charge on each particle is necessary for trapping it. 

We will be able to exceed this limit by repetitive 

Figure 2. High resolution micrograph showing 

turbostratic crystal structure in exhaust 

emission PM

Figure 3. High resolution micrograph of a graphitized 

particle emitted by a motor vehicle

Figure 4. Real-time single particle analyzer mass 

spectrometer in ORNL engine lab
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

84

charging of the particles, so when more mature the 

instrument’s upper size limit should be in the 

hundreds of nanometer range. Since the instrument 

is a mass spectrometer, we will also be able to 

simultaneously measure the neutral gas phase species 

as well as the particle phase species. Its tandem mass 

spectrometry (MS/MS) configuration is key to 

analyzing the organic materials present on the 

particles. This should yield unprecedented real-time 

information regarding particle nucleation and growth 

with minimal effort. Figure 4 shows the instrument 

as configured for the engine lab. A significant 

portion of the effort to date has been supported by 

laboratory exploratory funds. The initial undertaking 

was encouraged by DOE’s Dr. Sidney Diamond.

Conclusions

Development of more complete instrumentation 

for studying the characteristics of particulate 

emissions from both spark-ignited and compressionignited engines has made possible more 

comprehensive investigation of the similarities and 

differences between particles emitted from these 

engines. This level of investigation of particle 

characteristics is needed to more fully recognize and 

minimize the impacts of particle emissions on the 

health of the population. First steps have been taken 

towards a full characterization of particle emissions 

by revisiting the emissions from an older vehicle. 

Continuing work will focus on performing similar 

analyses on vehicles of current and emerging engine 

technology.

List of References

1. J.M.E. Storey, C. Scott Sluder, Douglas A. Blom, 

Oak Ridge National Laboratory, and Erin 

Higginbotham, Automotive Testing 

Laboratories, Inc., "Particulate Emissions from a 

Pre-Emissions-Control Era Spark Ignition 

Vehicle: A Historical Benchmark.," SAE paper 

2000-01-2213, June 2000.

2. "Northern Front Range Air Quality Study", 

Colorado State University, 1997.

List of Acronyms

EDS Energydispersive x-ray spectroscopy

PM Particulate Matter

RTAMS real time aerosol mass spectrometer

SwRI Southwest Research Institure

TEM transmission electron microscopy
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

85

D. Lubricity of High Volatility, Low Sulfur CIDI Fuels

Peg Whalen

National Renewable Energy Laboratory

1617 Cole Boulevard

Golden, CO 80401

(303) 275-4479, fax: (303) 275-4415, e-mail: peg_whalen@nrel.gov

DOE Program Manager: John Garbak

(202) 586-1723, fax: (202) 586-9811, e-mail: john.garbak@ee.doe.gov

Subcontractor: Southwest Research Institute, San Antonio, TX

This Project addresses the following OTT R&D Plan Barriers and Tasks:

Barriers

I. Infrastructure Impacts

Tasks

7. Vehicle Materials Compatibility

Objectives

• Characterize the lubricity of high volatility and low-sulfur compression ignition, direct injection 

(CIDI) fuels and explore additives to improve the lubricity of these fuels.

• Complete correlation of the High Pressure High Frequency Reciprocating Rig (HPHFRR) and the 

standard High Frequency Reciprocating Rig (HFRR).

Approach

• Conduct a series of baseline tests to compare the HPHFRR and the standard HFRR.

• Conduct a series of lubricity tests on selected fuels blended with different additives. 

Accomplishments

• HPHFRR and HFRR baseline tests showed better agreement than expected between two identical 

HFRR rigs (as outlined in Precision and Bias section of HFRR test method, ASTM D-6079).

• The lubricity of each fuel tested was improved by at least one of the additives evaluated, with the treat 

rates varying among the fuels.

Future Directions

• No future work is planned at this time.

Introduction

The lubricity of a fuel has a direct impact on the 

wear of engine components such as fuel injection 

systems. Testing the lubricity of promising fuels, fuel 

blends, and additives is a necessary part of evaluating 

the potential of advanced fuels. Advanced fuels will 

need to meet or exceed accepted lubricity levels for 

standard diesel fuels measured on an HFRR.

Many of the advanced fuels under consideration 

for use in advanced engines (such as DME) have 

high vapor pressures. As a result, these fuels are 

gaseous under ambient conditions and form a 
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

86

lubricating liquid only at elevated pressures. In 

addition, many fuel systems operate at elevated 

temperatures and pressures, which may not be 

adequately duplicated at ambient temperatures of the 

standard HFRR. 

In FY99, a project was initiated with Southwest 

Research Institute to design and develop a 

pressurized test rig to enable wear test evaluation of 

advanced diesel-type fuels. A pressurized fuel 

lubricity test apparatus, the High Pressure High 

Frequency Reciprocating Rig, was designed. It 

reproduces the operating conditions of the standard 

HFRR, but enables lubricity testing at elevated 

temperatures and pressures.

In this follow-on project, a series of tests were 

conducted to compare the results from the new 

HPHFRR and the standard HFRR. In addition, the 

HPHFRR was used to evaluate the lubricity of 

several fuels with and without additives. 

Approach

An initial test sequence was performed to verify 

the agreement between the HPHFRR and the results 

of standard HFRR tests performed according to 

ASTM D 6079 at 25o

C. The range of test conditions 

available on the HFRR and HPHFRR is described in 

Table 1. Tests were performed using a matrix of 44 

fuel and additive combinations. Only fuels with 

negligible vapor pressure at ambient temperature 

were evaluated, as fuels with high vapor pressure 

cannot be tested using the standard HFRR. Each of 

the different fluids was evaluated with both the 

HFRR and the HPHFRR at 25o

C, and a difference 

was computed.

Following the verification test series, a test series 

was conducted to evaluate the lubricity of very lowsulfur diesel (LSD), dimethyl ether (DME), and 

Fischer-Tropsch (FT) with four different additives. 

Treat rate curves were generated for four different 

additives. 

Results

The initial test sequence was performed to verify 

the agreement between the HPHFRR and the HFRR. 

ASTM D 6079 requires that the repeatability of the 

HFRR for tests performed by a single apparatus on 

identical test material should exceed 0.062 mm in 

only one case in 20. The reproducibility between 

data produced by two different operators in two 

different laboratories (essentially two different rigs) 

should not exceed 0.127 mm. In this study, which 

used two different machines within a single 

laboratory, the variability of the test results was 

expected to be between 0.062 and 0.127 mm. 

Parameter Units HRFF HPHFRR

Speed Hz 20-100 5-200

Load grams 100-1000 200

Stroke mm 0.1 to 2 0 to 2

Temperature o

C ambient to 

60

ambient to 

300

Pressure kPa ambient ambient to 7

Fuel Volume ml 2 25

Table 1. Range of test conditions available on HFRR 

and HPHFRR

Figure 1. Effect of additive concentration on lubricity of 

very low sulfur diesel (3-ppm sulfur) as 

measured by the HPHFRR at 25oC

Figure 2. Effect of additive concentration on lubricity of 

FT diesel as measured by the HPHFRR at 25o

C
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

87

The differences (HPHFRR results minus HFRR 

results) in this test series were found to follow a 

Gaussian distribution. On average, the results 

produced by the HPHFRR were 0.0049 mm lower 

than those of the HFRR. A paired t-test was 

approximately 0.90, indicating no significant 

difference in the average test results. Overall, the 

agreement between the HPHFRR and HFRR was as 

good as or better than the ASTM defined acceptable 

variability limit between two HFRR machines of 

0.127 mm.

The suitability of four additives in improving the 

lubricity of fuels was evaluated. The fluids evaluated 

included a very low sulfur diesel (3-parts per million 

sulfur), a Fischer-Tropsch diesel, and DME, which 

has high volatility compared to the other fuels. The 

additives selected included a wide range of 

chemistries, including organic mono and dimer acid 

based compounds, as well as modern non-acidic and 

synthetic ester based chemistries. The results of 

HPHFRR tests performed as a function of additive 

concentration are plotted in Figures 1, 2, and 3 for 

the LSD, FT and DME fuels, respectively. The 

industry accepted maximum allowable wear scar 

diameter for HFRR tests at 25o

C is 0.380 mm. The 

line at 0.380 mm on Figure 1, 2, and 3 is the pass/fail 

line indicating the wear scar limit. Each of the 

additives was effective at improving lubricity at a 

concentration of 100 ppm or below when used with 

the LSD fuel (see Figure 1). Further increases in 

additive concentration resulted in only marginal 

improvement in lubricity. 

Changes in additive chemistry had varying 

effects on performance when used in the FT fuel (see 

Figure 2). A newer non-acidic additive chemistry 

was less effective at all levels than the other additives 

evaluated, only achieving acceptable lubricity result 

at the highest treat rate evaluated. Additive treat rates 

of 50 to 100 mg/L were required to achieve 

acceptable lubricity in FT fuel.

The lubricity of neat DME is much worse than 

that of most other diesel fuels. As a result, high 

additive concentrations are required to reduce wear 

to an acceptable level, as shown in Figure 3. Only the 

synthetic ester additive produced acceptable wear at 

a concentration of 100 mg/L. 

Conclusions

The High Pressure High Frequency 

Reciprocating Rig was developed to evaluate wear 

characteristics of volatile fuels. It may also be used to 

evaluate lubricity of conventional liquid fuels at high 

temperature. Other than test pressure and 

temperature, the contact parameters exactly duplicate 

those of the standard HFRR. The reproducibility 

between the HPHFRR and HFRR was equivalent to 

that expected to occur between two conventional 

HFRR apparatuses.

Unadditized FT and low sulfur diesel fuels have 

poor lubricity, which may be improved by use of 

certain lubricity additives. One non-acidic based 

additive was not effective in the FT fuel. DME has 

exceptionally poor lubricity, worse than conventional 

diesel fuels. DME lubricity can be improved by using 

additives, but the concentrations required can be as 

much as twice that needed for diesel fuels.

List of References

1. American Society for Testing and Materials, 

"Annual Book of ASTM Standards 2000, Section 

Five: Petroleum Products, Lubricants and Fossil 

Fuels," Volume 05.04, 2000.

List of Publications

1. "Lubricity of Volatile Fuels for Compression 

Ignition Engines," SAE Paper No. 00FL-422, 

presented at CEC/SAE Spring International 

Fuels and Lubricants Meeting, June 2000.

Figure 3. Effect of additive concentration on lubricity of 

DME as measured by the HPHFRR at 25o

C
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

88

List of Acronyms

ASTM American Society for Testing and 

Materials

CIDI compression ignition, direct 

injection

DME dimethyl ether

FT Fischer-Tropsch

HFRR High Frequency Reciprocating Rig

HPHFRR High Pressure High Frequency 

Reciprocating Rig

LSD low sulfur diesel

ppm parts per million
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

89

E. Refinery Modeling of the Production of Advanced Petroleum-Based Fuels

Gerald Hadder (primary contact)

Oak Ridge National Laboratory

7701 St. John Road, #2143

Glendale, AZ 85308

(623) 322-2406, fax: (623) 322-2406, e-mail: haddergr@ornl.gov

David Greene

Oak Ridge National Laboratory

P.O. Box 2008, MS 6073

Oak Ridge, TN 37831-6073

(865) 574-5963, fax: (865) 574-3851, e-mail: greenedl2@ornl.gov

DOE Program Manager: Peter Devlin

(202) 586-4905, fax: (202) 586-9811, e-mail: Peter.Devlin@ee.doe.gov

DOE Program Manager: Barry McNutt

(202) 586-4448, fax: (202) 586-4447, e-mail: Barry.McNutt@hq.doe.gov

Contractor: UT-Battelle

LLC Prime Contract No. DE-AC05-00OR22725

Subcontractors: Energy and Environmental Analysis, Inc. , Arlington, VA; EnSys Energy and Systems, Flemington, NJ; H.T. McAdams, AccaMath Services, Carrollton, IL; R.W. Crawford, RW Crawford Energy Systems, Tucson, AZ

This Project addresses the following OTT R&D Plan Barriers and Tasks:

Barriers

G. Advanced Fuel Production and Cost

Tasks

5. Refinery and Fuel Processing Economics

Objectives

• Characterize relationships between fuel properties and emissions for diesel technologies that could be 

available to meet Tier 2 emissions standards. 

• Develop methodology for relating diesel fuel composition to emissions from advanced diesel 

engines.

• Make preliminary estimation of impacts of alternative diesel fuel specifications on U.S. refineries. 

• Develop composited refinery model.

• Use refinery model for estimation of impacts of alternative diesel fuel specifications on U.S. 

refineries.
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

90

Approach

• Stage 1. Define engine emission control technologies available to meet Tier 2 standards. Analyze 

relationships of fuel composition, additives, and emissions from advanced engines. Define range of 

fuel parameter values that could affect ability of engines to meet standards.

• Stage 2. Analyze cases based on diesel fuel specifications from Stage 1. Use spreadsheet-based 

approach to estimate shifts in diesel fuel blendstocks and refinery operations. Use results from Stage 2 

in screening fuels for Stage 4.

• Stage 3. Use eigenfuel concept to analyze diesel data to understand the role of fuel composition 

changes on emissions from advanced diesel engines

• Stage 4. Modify Oak Ridge National Laboratory Refinery Yield Model (ORNL-RYM) by 

compositing crude oils, for improved analyst productivity and greater credibility with industry. Add 

promising technologies to model. 

• Stage 5. Use Stage 3 refinery model for scenario studies of fuel quality changes identified in Stages 1 

and 2. Estimate costs, shifts in diesel fuel blendstocks, and other refining impacts. Use global model 

to evaluate impacts of increased reformulated diesel fuel (RFD) demand on U.S. refinery viability.

Accomplishments

• Composited version of ORNL-RYM completed.

• Initial case studies completed for estimating refinery impacts of reformulated diesel fuel.

• Eigenfuel methodology developed for relating diesel fuel emissions to fuel composition. 

Future Directions

• Analyze RFD production sensitivities to future market circumstances, including phased introduction.

Introduction

To achieve the potential use of a large number of 

future diesel engines, diesel’s pollution problems 

must be solved. Diesel fuel quality improvements 

could enable diesel engines with advanced emission 

control systems to achieve necessary emissions 

performance. Because of increased processing 

difficulty for quality improvements in reformulated 

diesel fuel (RFD) production, a large demand for 

RFD will present technical and economic challenges 

for the U.S. refining industry. It is important to the 

national economy and security that these challenges 

do not adversely affect the efficiency and reliability 

of transportation fuel production and distribution 

systems. Refinery modeling and advanced statistical 

methods are being used to study impacts of RFD 

production.

Approach

EnSys Energy and Systems used the latest 

uncomposited version of ORNL-RYM to analyze the 

processing and cost effects of diesel sulfur reduction 

(EnSys Energy & Systems, Inc. 2000). 

Conclusions 

This analysis is a preliminary step in the task 

sequence that leads to use of the composited version 

of ORNL-RYM in RFD production studies. Key 

results are summarized in Figures 1 and 2, which 

show incremental and differential costs of sulfur 

reduction. The average cost increase for RFD 

ranges from 5 cents per gallon (cpg) at 50 parts per 

million (ppm) sulfur to 11 cpg at 8 ppm. The 

Figures show the sensitivity of cost to revamping 

opportunities. Focusing on manufacturing cost, this 

study did not allow for benefits of market and 

production flexibilities. The study design also 
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

91

separated investment decisions for low sulfur 

gasoline and RFD, eliminating potential cost 

reduction through integrated investment. Process 

economics were based on proven and recently 

commercialized technologies. Future catalyst or 

process improvements may reduce costs.

The composited version of ORNL-RYM may 

indicate more or less severe impacts of diesel fuel 

reformulation. Table 1 summarizes case studies to be 

performed with the composited model.

The ORNL-RYM analysis used RFD property 

specifications, rather than emissions performance 

specifications. Emissions modeling could provide a 

means for predicting the emissions performance of 

RFD, given fuel sulfur content, cetane number, and 

other property values. An emissions model could 

give refiners significant technical and economic 

flexibility in RFD production. AccaMath Services 

and RWCrawford Energy Systems have developed a 

methodology for estimating an RFD emissions 

model (McAdams, Crawford and Hadder 2000). 

Because of fuel property covariance, it is found 

advantageous to redefine predictor variables as 

vectors, in which original fuel properties are 

components, rather than as scalars each involving 

only a single fuel property. The approach clearly 

shows that only a few basic patterns of fuel-property 

variations affect emissions. Given adequate engineemissions test data, an RFD emissions model will be 

used in future ORNL-RYM studies.

List of References

1. McAdams, H.T., R.W. Crawford and G.R. 

Hadder. 2000. "A Vector Approach to 

Regression Analysis and Its Application to 

Heavy-Duty Diesel Emissions," Society of 

Automotive Engineers, Paper 2000-01- 1961, 

June.

2. EnSys Energy & Systems, Inc. 2000. "Modeling 

Impacts of Reformulated Diesel Fuel," ORNL 

Cases Key Premises

Base case LSG30 (Case 1)

Key cases

Low-sulfur RFD (Case 2)

Regulation of off-road distillates (Case 3)

Volume-phased introduction of RFD (Case 4)

Follow-up and sensitivity 

cases

Low-sulfur and low aromatics RFD (Case 5)

Refinery modeling with preliminary Complex Model for diesel fuel emissions. Use of oxygenates in RFD 

blending (Case 6)

RFD impacts on refineries of different capabilities

Mid-capability (Case 7)

Challenged (Case 8)

LSG30, winter (Case 9)

Technology sensitivity (Case 10)

Impacts of additional constraints on jet fuel quality (Case 11)

Table 1. Refinery Modeling Study Matrix for RFD

Figure 1. RFD Cost Increase Figure 2. Differential RFD Cost
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

92

Subcontract 80X-SY527V, Draft, Flemington, 

NJ, June 6. 

List of Acronyms

cpg cents per gallon

LSG30 low sulfur gasoline with 30 ppm 

sulfur

ORNL-RYM Oak Ridge National Laboratory 

Refinery Yield Model

ppm parts per million

RFD reformulated diesel fuel
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

93

F. Fuel Property and Emissions Database

Peg Whalen

National Renewable Energy Laboratory

1617 Cole Boulevard

Golden, CO 80401

(303) 275 4479, fax: (303) 275 4415, e-mail: peg_whalen@nrel.gov

DOE Program Manager: John Garbak

(202) 586-1723, fax: (202) 586-9811, e-mail: john.garbak@ee.doe.gov

DOE Program Manager: Stephen J. Goguen

(202) 586-8044, fax: (202) 586-1600, e-mail: stephen.goguen@ee.doe.gov

NREL Computer Support: Paul Bergeron, Mark Winter, and Karen Guilbeault

This Project addresses the following OTT R&D Plan Barriers and Tasks:

Barriers

A. Fuel Property Effects on Engine Emissions and Efficiency

B. Fuel Property Effects on Exhaust Emission Control System Technology

C. Emission Control System Degradation

D. Sulfur Impacts

E. Toxic Emissions

F. Ultra-fine Particles

G. Advanced Fuel Production and Cost

H. Health, Safety, and Regulatory

I. Infrastructure Impacts

Tasks

4. Develop Empirical Relationships

9. Test and Validate the Empirical Relationships

Objective

• Establish a web-based, searchable fuel property database for the Advanced Petroleum-Based Fuels 

Program, which links to available emissions data.

Approach

• Define the fuel properties and related information to be included in the database.

• Build the database, web pages and appropriate web interfaces for the searchable database. 

Accomplishments

• Searchable fuel property database completed and available on World Wide Web at http://

www.ott.doe.gov/fuelprops/, includes link to available heavy vehicle emissions data.
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

94

Future Directions

• Will continue to populate database with new fuels and property data, as they become available from 

various fuel-related projects. Plan to expand emissions database to include light-duty emissions data, 

and engine-out emissions data.

Introduction

Numerous studies have investigated the impact 

of fuel properties, such as density, aromatic content, 

and cetane number on emissions from various diesel 

engines. Fuel properties directly affect engine 

operation, as well as emissions. Engine systems, like 

fuel injection systems, are impacted as fuel 

properties change. As engine systems advance and in 

many cases become more complex, it becomes more 

critical to understand how fuels are changing and the 

impact of those changes on engine performance and 

emissions. 

The Advanced Petroleum-Based Fuels Program 

includes a Systems Emission Reduction analysis 

effort which will develop predictive tools for 

estimating the effects that fuel property variations 

can have on the emission response of engines, and 

exhaust emission control systems. A detailed fuel 

property database is a key information component 

and resource for the development of these predictive 

empirical models.

Approach

The development of the fuel property database 

includes the following tasks:

• Review of generally available fuel property data, 

and evaluation of property data that are needed to 

develop empirical models.

• Organization and development of database for 

the fuel property data.

• Gathering available fuel property data, and 

populating the database.

• Development of the web interface to enable the 

data to be available to DOE research partners via 

the Internet. 

Results

The fuel property database was developed to 

include physical, chemical, and operability property 

data, and environmental health and safety 

information. The database is accessible via the World 

Wide Web at http://www.ott.doe.gov/fuelprops/ (see 

Figure 1).

The database was setup to allow the user to select 

individual fuels or properties, or to select all fuel and 

all property data. The initial page includes lists of 

fuels and properties that can be selected (see Figure 

2). Output can be displayed in either SI or English 

units. The users can also access information on the 

test method used to obtain the property data, the 

reference source for the data, and a brief description 

of the fuel. Figure 3 provide a sample of the results a 

user would get back from a query, with all selected 

(or available) data displayed in a table format.

Figure 1. Fuel Property Database Home Page Logo

Figure 2. Fuel property database selection page, includes 

pull-down lists of fuels and properties
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

95

The database is also linked to the heavy vehicle 

chassis emissions data available from various DOE 

projects managed by NREL. The user can select the 

fuel which he or she is interested in (see Figure 4). 

The list only includes fuels for which emissions data 

are currently available. The emissions query works 

similarly to the fuel property query, with data 

displayed in a summary table. 

Conclusions

The fuel property database has been designed 

and developed, and it is being populated with fuel 

property data from various sources and programs. 

The database is accessible to DOE research partners 

via the Internet. This database is a warehouse of fuel 

properties, and it is one of the significant data sets 

that will be utilized to develop predictive tools for 

estimating the effects that fuel properties have on 

emissions and emissions control system 

performance.

Figure 3. Sample results from fuel property query

Figure 4. Heavy vehicle chassis emissions data selection 

page
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

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Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

97

V. ADVANCED FUELS FOR FUEL CELLS

A. Fuel Composition Effects on Fuel Processing Performance

Rod Borup (Primary Contact), Michael Inbody, Byron Morton, JinKi Hong, and Jose Tafoya

Los Alamos National Laboratory

ESA-EPE, MS J580 P.O. Box 1663

Los Alamos, NM 87545

(505) 667-2823, fax: (505) 665-6173, e-mail: Borup@lanl.gov

DOE Program Manager: Peter Devlin

(202) 586-4905, fax: (202) 586-9811, e-mail: Peter.Devlin@ee.doe.gov

This Project addresses the following OTT R&D Plan Barriers and Tasks:

Barriers

E. CO Poisoning

F. Fuel Processor System Integration and Efficiency

G. Fuel Processor Startup/Transient Operation

Tasks

3. Fuel-Flexible Fuel Processor Component and Materials Development

Objectives

• Explore the effects of various fuels, fuel components and fuel impurities on the performance of 

onboard hydrogen generation technologies

• Measurement of fuel effects on fuel processor performance and durability

- Fuel composition and component effects

- Fuel impurity effects

• Measurement of automotive-scale (50 kW) fuel processor performance and durability

• Measurement of fuel effects on catalyst durability

Approach

• Develop automotive-scale fuel processor test capabilities for:

- Precision measurement of flow, pressure, temperature, and chemical species;

- Transient control and measurement; and

- Operation on hydrocarbon fuels with capability to blend test impurities into fuels and fuel 

mixtures.

• Examine commercial and LANL prepared catalysts.

- Measure adiabatic reforming performance; and 

- Determine kinetics and performance under iso-thermal conditions.
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

98

Accomplishments

• Completed installation of fuel processor test capabilities including:

- Gas composition and emissions analysis instrumentation.

- Experiment automation.

- Initiated testing with an Autothermal Fuel-Flexible Fuel Processor.

- Designed, constructed and operated adiabatic catalyst test reactor.

- Operation of isothermal catalyst test reactor.

- Received modular pressurized flow reactor.

- Verified operation of Autothermal Fuel-Flexible Fuel Processor on natural gas.

- Verified test facility operation and capabilities including reactant management, pressure control, 

and emissions instrumentation.

- Initiated testing of liquid hydrocarbon fuels.

Future Directions

• Study fuel processor operation on petroleum-based fuels to evaluate effects of fuel constituents

- Monitor carbon formation in situ by use of adiabatic reactor and laser scattering.

- Map carbon formation of individual fuel constituents with operating conditions.

- Examine commercial catalysts to observe carbon formation tendencies.

- Measure fuel processor operation with individual fuel constituents and fuel blends.

- Measure fuel processor operation with fuel impurities.

- Measure fuel processor transient operation including startup/shutdown and variations in flow 

rates.

- Use modular reactor to examine fuel effects with a homogeneous reactor.

• Integrate fuel cell stack testing with fuel processor operation to evaluate system integration effects of 

fuels.

Introduction

This report describes our FY00 technical 

progress in examining fuel effects on hydrogen 

generation technology research for the specific 

purpose of hydrogen production for protonexchange-membrane (PEM) fuel cells. The goal of 

this research is to explore the effects of various fuels, 

fuel constituents and fuel impurities on the 

performance of on-board hydrogen generation 

devices and consequently on the overall performance 

of a PEM fuel cell system utilizing a hydrocarbon 

fuel.

Fuels and fuel impurities have effects on fuel 

processor operation, efficiency, reformate gas 

composition, transient performance, lifetime, and 

durability. These effects are being investigated 

through experiments with various fuel processor 

hardware in Los Alamos National Laboratories’ fuel 

processor test facility. The fuel effects ultimately 

determine the performance and operation of the fuel 

cell system from their effect on the anode feed 

stream composition.

In this report, we describe our progress of 

examining fuel composition effects on fuel 

processing, including the use of various fuel 
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

99

constituents, fuel impurities, reaction catalysts, fuel 

processor test reactors and reactor test systems. 

Approach: Fuel Processors and Fuel 

Processor Test Capabilities

The fundamental tools for our research on the 

effects of fuels and fuel impurities on on-board 

hydrogen generation technology are the reactor test 

beds in which the fuel effects are monitored and the 

gas analysis and catalyst characterization techniques 

employed in this work. The balance-of-plant 

framework, the necessary analytical instrumentation 

and the supervisory control to characterize operation 

and performance of different fuel processors and fuel 

components allows determination of fuel component 

effects on fuel processing. Different reactors serve 

complementary roles in our laboratory, including 

integrated and modular fuel processing systems, 

heterogeneous and homogeneous oxidation, and 

adiabatic and isothermal test beds.

The Fuel-Flexible Fuel Processor (F3

P) is an 

integrated fuel processor incorporating a partial 

oxidation reformer (auto-thermal reformer), a hightemperature shift reactor, a zinc oxide sulfur-removal 

bed, a low-temperature shift reactor, integral steam 

generator, and combustion-driven fuel vaporizer. 

This fuel processor is being used for studying the 

effects of fuels and fuel impurities on a thermally 

integrated system where the interactions between 

components are close-coupled. The fuel processor, 

shown in Figure 1, was received from Hydrogen 

Burner Technology and was operational as of 

January 2000. Initial operation of this system was 

conducted on gaseous fuels, methane and natural gas, 

after which liquid fuel testing was initiated.

The Modular Pressurized Flow Reactor (MPR) 

received from Nuvera (Epyx), is a fuel processor 

incorporating sequential/modular unit operations of 

the different fuel processing sections. This modular 

configuration can be seen in the isometric drawing of 

the reactor shown in Figure 2. This reactor will be 

installed and made operational in the 4th quarter of 

FY2000.

An adiabatic reactor for use in evaluating fuel 

components and the fuel component tendency for 

carbon formation is shown in Figure 3. This reactor 

Figure 1. Autothermal Integrated Fuel Flexible Fuel 

Processor

Figure 2. Isometric drawing of the Modular Pressurized 

Flow Reactor

Figure 3. Adiabatic partial oxidation reactor
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

100

incorporates ease of catalyst replacement, in situ

carbon formation monitoring, gas and temperature 

measurements with radial and axial profiles. The 

reactor was operational in May 2000, the in situ

carbon formation monitoring will be added in the 4th 

quarter of FY2000. Figure 4 is a schematic showing 

laser detection for in situ carbon formation. An 

argon ion laser will be used with extinction 

monitoring to observe the onset of carbon formation. 

Scattering will used to observe relative carbon 

particle size distributions, and spectral detection will 

allow for fluorescence detection of PAHs (polycyclic-aromatic-hydrocarbons).

A micro-scale isothermal catalyst test bed for use 

in fuel and catalyst measurements under well defined 

and controlled conditions uses a furnace to keep the 

reactor under isothermal conditions. This reactor is 

constructed of a quartz tube with typical catalyst 

samples of 300 - 500 milligrams.

Results: Fuel Constituent Effects 

Initial operation of the autothermal reactor was 

conducted with gaseous fuels, specifically natural 

gas and pure methane. The transition between 

natural gas and pure methane is shown in Figure 5. 

As the fuel to the fuel processor was changed from 

natural gas to methane, the reactor control 

temperature (not shown in Figure 5) decreased. The 

control software increased the relative O/C ratio, 

which resulted in a higher auto-thermal outlet 

temperature. The higher temperature resulted in a 

higher conversion of methane, thus lower methane 

composition out of the reactor. It appears this is the 

result of differences in heat of combustion of the 

fuels. Even though the natural gas composition 

included 97% methane, calculating the heat of 

combustion shows significant differences at low O/

C. The stoichiometric combustion of methane and 

natural gas have heat of combustions of 212.8 and 

213.9 kJ/mol - less than a 0.5 % difference, however 

the heat of combustion of the fuels at O/C = 1 is 

35.65 and 37.43 which is over 5 % different. The 

natural gas composition was 97.067% methane, with 

small amounts of ethane (1.479%), propane 

(0.203%), butanes (0.0622%), pentanes (0.0197%), 

C6 (0.0144%), N2 (0.172%) and CO2 (0.978%).

Figure 6 shows hydrogen production from isooctane and iso-octane doped with 100 ppm sulfur. 

This test was conducted with a nickel supported on 

alumina catalyst. The initial hydrogen production, 

shown in Figure 6 as ml/min, was similar for both 

Figure 4. Schematic for the in situ measurement of 

carbon formation

Figure 5. Operation of autothermal reactor showing 

transition of operation between pure methane 

and natural gas.

Figure 6. Hydrogen production from iso-octane and isooctane with 100 ppm sulfur
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

101

fuel compositions. However, the iso-octane with 100 

ppm sulfur within five hours saw reduced hydrogen 

production, which was the result of much lowered 

iso-octane conversion. The pure iso-octane fuel has 

consistent hydrogen production over the test period 

of 24 hours. The sulfur effect on this catalyst appears 

to have greatly inhibited both the oxidation and 

steam reforming kinetics, thus lowering the isooctane conversion. This effect has been observed to 

be less severe on nickel catalysts supported on 

ceria.(1)

Carbon formation has been monitored by the 

carbon buildup on the catalyst surface over time as a 

function of different fuel components. Figure 7 

shows the XPS (X-ray Photoelectron Spectroscopy) 

C1s signal for a nickel catalyst sample tested with 

iso-octane, pentene, methylcyclohexane and xylene. 

This shows relative carbon formation to be much 

higher with the aromatic and unsaturated compounds 

than the aliphatic hydrocarbons.

Conclusions

Test capabilities have been developed which are 

capable of testing fuel processors with gaseous and 

liquid fuels. These capabilities provide the balanceof-plant necessary to support operation of fuel 

processor systems including analytical 

instrumentation and the supervisory control required 

to characterize operation and performance of 

different fuel processors and fuel components.

These capabilities are being used to measure fuel 

constituent and fuel impurity effects on fuel 

processor technology. Differences between natural 

gas and pure methane have been observed which can 

be explained by the difference in heat of combustion 

at low O/C ratios. The effect of sulfur on hydrogen 

production has shown dramatic effects on a Ni/Al2O3

catalyst, with hydrogen production (iso-octane 

conversion) decreasing by over a factor of 3 within 

only five hours of operation. The tendency for 

carbon formation has been observed to be a function 

of the fuel component, with the general trend for 

carbon formation: xylene > methyl cyclohexane > 

pentene > iso-octane.

List of References

1. J. Kopasz, "Effects of Fuels/Contaminants on 

Reforming Catalysts" presented at the Annual 

National Laboratory R&D Meeting, DOE Fuel 

Cells for Transportation Program, Richland, WA, 

June 7, 2000.

List of Presentations

1. "Measurement of the Effects of Fuel 

Constituents on Fuel Processor Performance," 

Presentation to the AIChE, Atlanta, GA, March 

2000.

2. Presentation at the 2000 Lab Review Meeting, 

Argonne, IL, May 2000.

List of Acronyms

CNG Compressed natural gas

F3

P Fuel-Flexible Fuel Processor

HBT Hydrogen Burner Technology

kW Kilowatt

LANL Los Alamos National Laboratory

MPR Modular Pressurized Flow Reactor

PAH Polycyclic Aromatic Hydrocarbons

XPS X-ray Photoelectron Spectroscopy

Figure 7. XPS (x-ray photoelectron spectroscopy) of 

catalysts (a) initial carbon signal, and after 

partial oxidation with (b) iso-octane, (c) 1-

pentene, (d) methylcyclohexane (e) p-xylene
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

102

B. Effects of Fuel Constituents on Fuel Processor Catalysts

John P. Kopasz (primary contact), Dan Applegate, Lillian Ruscic, Shabbir Ahmed

Argonne National Laboratory

9700 South Cass Avenue

Argonne, IL 60439

(630) 252-7531, fax: (630) 972-4405, e-mail: Kopasz@cmt.anl.gov

DOE Program Manager: Peter Devlin

(202) 586-4905, fax: (202) 586-9811, e-mail: Peter.Devlin@ee.doe.gov

This Project addresses the following OTT R&D Plan Barriers and Tasks:

Barriers

E. CO Poisoning

F. Fuel Processor System Integration and Efficiency

G. Fuel Processor Startup/Transient Operation

Tasks

3. Fuel-Flexible Fuel Processor Component and Materials Development

Objectives

• Identify the effects of major constituents, additives, and impurities in petroleum based fuels on 

reformer performance.

• Determine the effects of alternative fuels (methanol, ethanol, DME, Fischer-Tropsch liquids) on 

reformer performance.

• Evaluate the effects of fuel constituents and impurities on catalyst stability.

Approach

• Investigate autothermal reforming of major constituents individually in a microreactor.

• Rate performance based on:

- Byproduct formation,

- Catalyst deactivation, and

- Dependence of hydrogen yield and conversion efficiency on temperature and residence time.

• Test selected minor constituents, additives, and impurities by mixing with iso-octane.

• Use long-term tests (1000 h) to determine effects of fuel components on catalyst stability, poisoning 

and long-term degradation.

Accomplishments

• Completed short-term testing of 6 gasoline components.

• Made recommendations to DOE on benchmark fuel compositions.

• Completed long-term tests on isooctane and two benchmark fuels, one without sulfur, one with sulfur.

• Initiated tests on effects of sulfur impurities.
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

103

 Future Directions

• Continue investigation of reforming of gasoline constituents - focusing on olefins and minor 

constituents which may be problematic such as napthalenes and substituted aromatics and begin to 

look at synergistic effects.

• Investigate effects of additives (detergents, antioxidants) and impurities.

• Investigate differences in sulfur effects with different catalysts.

Introduction

On-board reforming of petroleum based fuels, 

such as gasoline, may help ease the introduction of 

fuel cell vehicles to the marketplace. Although 

gasoline can be reformed, some constituents and 

impurities may have detrimental effects on the fuel 

processing catalysts (which may lead to 

compromised performance and decreased fuel 

conversion efficiency). In order to identify which 

constituents are beneficial and which are detrimental 

to the reformer we have begun a program to test 

various components of gasoline under autothermal 

reforming conditions. 

The current work focuses on the autothermal 

reforming of iso-octane, n-octane, trimethylbenzene, 

toluene, methylcyclohexane, and 

methylcyclopentane. These chemicals represent the 

branched paraffins, straight chain paraffins, 

aromatics, and cyclic paraffins present in gasoline. In 

addition, we have investigated the effects of sulfur 

impurities on the reforming of isooctane. These 

results will be used to help determine the 

requirements for a fuel cell fuel and determine if a 

special fuel cell-grade gasoline formulation would 

improve overall system performance.

Approach

We have chosen representative chemicals from 

gasoline and are investigating the autothermal 

reforming of these compounds as a function of 

temperature and space velocity. Reforming was 

performed under constant O2:C and H2O:C ratios 

(0.42 and 1.4) on identical catalysts to allow for 

comparisons between the different chemicals. 

Short term (<20h) tests were performed in a 

reactor designed to allow for sampling at different 

space velocities. Four sampling ports allow for 

testing at various positions in the catalyst bed. A 

small portion (< 1%) of the gas stream is diverted 

through one of these ports to the residual gas 

analyzer for analysis. The remainder of the gas 

stream continues through the reactor bed to the exit 

stream. Batch sampling can be performed at the 

reactor exit.

Long-term tests (> 1000 h) were performed to 

determine the durability of the autothermal 

reforming catalyst and to determine if there are any 

long-term problems (poisoning, coking) caused by 

the fuel components. 

Results

Short-term tests

All of the gasoline components investigated to 

date were converted to a hydrogen rich gas at 800o

C 

and a Gas Hourly Space Velocity (GHSV) of 15,000/

h. Conversions were all above 95%. Hydrogen 

selectivities were generally close to 80% at 800o

C 

(see Figure 1). 

Figure 1. Comparison of Autothermal Reforming 

Conversion Efficiency and Hydrogen 

Selectivity for Various Gasoline Constituents
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

104

The temperature dependence for hydrogen 

production from several gasoline constituents at a 

GHSV of 15,000/h is shown in Figure 2. 

Temperature has the largest effect on 

trimethylbenzene reforming and the smallest effect 

on isooctane reforming. The general trend indicates 

aromatic compounds (trimethylbenzene and toluene) 

require higher temperatures than napthenes, which 

require higher temperatures than straight chain and 

branched paraffins. 

We have also investigated the effect of GHSV on 

autothermal reforming of several gasoline 

constituents. Results are illustrated in Figure 3. 

Again, trimethylbenzene reforming is the most 

sensitive. Hydrogen yield dropped dramatically 

when the GHSV was increased from 15,000/h to 

75,000/h. The next most sensitive components were 

isooctane and n-octane, while toluene and 

methylcyclohexane were the least sensitive to 

increases in GHSV. 

Effect of Sulfur

Sulfur impurities may pose a large problem for 

fuel processing. To determine the effects of sulfur 

impurities on the autothermal reforming catalyst we 

have reformed isooctane doped with benzothiophene 

to provide sulfur levels of 300 and 1000 wppm S. A 

comparison of the hydrogen production from pure 

isooctane and sulfur doped isooctane reformed over 

two different Pt containing catalysts is shown in 

Figure 4. For both catalysts hydrogen production 

was higher for the isooctane with sulfur added than 

for pure isooctane. 

Nickel was substituted for Pt in the preparation 

of our ANL catalyst, and the sulfur tolerance of this 

catalyst was investigated. The results are shown in 

Figure 5. Reforming was initiated with pure 

isooctane. At ~ 4000 s the fuel was switched to 

Figure 2. Effect of Temperature on Hydrogen Yield from 

Autothermal Reforming of Gasoline 

Constituents

Figure 3. Effect of Increasing GHSV on the Reforming 

of Various Gasoline Components

Figure 4. Effect of Sulfur on Isooctane Reforming over 

Pt Containing Catalysts

Figure 5. Effect of Sulfur on Isooctane Reforming Over a 

Ni Containing catalyst
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

105

isooctane doped with benzothiophene to provide 380 

wppm S. After the fuel was switched the hydrogen 

production returned to the level observed with pure 

isooctane, but then decreased. Eventually the 

hydrogen production leveled off about 15% lower 

than that for pure isooctane. The fuel was switched 

back to pure isooctane and reforming continued for 

several hours. After this period the hydrogen 

production had returned to the initial level observed 

for pure isooctane over the virgin Ni catalyst.

Long-term Tests

Long-term (≥ 1000 h) tests were performed on Pt 

containing catalysts under autothermal reforming 

conditions. Tests were performed at temperatures of 

700 to 750o

C at a GHSV of 4400/h, with start/stop 

cycles to provide thermal cycling. Product gas 

composition was followed over the length of the tests 

to determine if there was any substantial degradation 

in catalyst performance over time. Results with 

isooctane indicate the total gas output dropped by 6% 

after 1000 h of operation while the hydrogen output 

dropped by approximately 10%. Test results for a 

benchmark fuel (74 wt% isooctane, 20 wt% 

dimethylbenzene, 5 wt% methylcyclohexane and 1 

wt% 1-pentene) are shown in Figure 6. There was 

less than a 5% decrease in hydrogen production after 

1000 h of operation. 

The effects of sulfur on long-term performance 

were investigated by doping the benchmark fuel with 

benzothiophene to provide a sulfur content of 50 

wppm. Results again indicated an increase in 

hydrogen production for fuel containing sulfur 

compared to fuel with no sulfur present, even after 

1700 h. A comparison of the catalyst performance 

with the benchmark fuel plus sulfur to the benchmark 

fuel without sulfur is shown in Figure 7.

Conclusions

This work indicates that all of the major types of 

chemicals found in gasoline (straight-chain and 

branched paraffins, napthenes, and aromatics) can be 

autothermally reformed to provide a hydrogen rich 

gas. Of the components tested trimethylbenzene 

required the most severe reforming conditions, 

requiring both high temperature (800o

C) and low 

space velocities. This suggests a gasoline without 

trimethylbenzene would lead to higher overall 

efficiency and may allow for smaller catalyst beds 

operating at lower temperatures. The effects of sulfur 

impurities on the catalyst are dependent on the 

catalyst. Sulfur appears to improve the hydrogen 

yield for Pt containing catalysts but appears to 

reversibly poison Ni containing catalysts. There was 

no major long-term degradation caused by adding 

unsaturated components or sulfur to the fuel.

List of Publications

1. Summary of work published in Advances in 

Hydrogen Energy, Kluwert Academic 

Publishing, 2000.

List of Presentations

1. Presentation at the 1999 ACS National Meeting.

2. Presentation at the 2000 AIChE Annual Meeting.

3. Presentation at the 2000 Fuel Cell Seminar.

Figure 6. Long-term Test Indicates Little Degradation 

over 1000 h of Operation with Benchmark Fuel

Figure 7. Comparison of Long-Term performance with 

Benchmark Fuel and Benchmark Fuel+50 

wppm S
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

106

List of Acronyms

DME Dimethyl ether

DOE U.S. Department of Energy

GHSV Gas Hourly Space Velocity

Ni Nickel

Pt Platinum

S Sulfur 
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

107

C. Sulfur Removal from Reformate

Theodore Krause (primary contact), Joong-Myeon Bae, Romesh Kumar, and Michael Krumpelt

Argonne National Laboratory

9700 South Cass Avenue

Argonne, IL 60439

(630) 252-4356, fax: (630) 972-4463, e-mail: krause@cmt.anl.gov

DOE Program Manager: Peter Devlin

(202) 586-4905, fax: (202) 586-9811, e-mail: Peter.Devlin@ee.doe.gov

This Project addresses the following OTT R&D Plan Barriers and Tasks:

Barriers

E. CO Poisoning

F. Fuel Processor System Integration and Efficiency

G. Fuel Processor Startup/Transient Operation

Tasks

3. Fuel-Flexible Fuel Processor Component and Materials Development

Objectives

• Define maximum H2S concentration for fuel processor and fuel cell catalysts.

• Develop a sulfur removal process based on adsorption technology that reduces the H2S concentration 

in reformate to <1 ppm under fuel processing conditions.

• Determine the appropriate operating parameters (e.g., H2S equilibrium, sulfur loading, temperature, 

space velocity) for candidate adsorbents.

• Evaluate the performance of the candidate adsorbents in both a microreactor test system and an 

integrated fuel processor system.

• Identify and develop alternative sulfur removal technologies if required to meet sulfur tolerance 

requirements of new catalysts.

 Approach

• Perform thermodynamic calculations to estimate H2S tolerance of fuel processor and anode catalysts 

(bulk sulfide formation) and to predict H2S equilibrium partial pressure for candidate adsorbents.

• Conduct modeling to optimize the geometry of the adsorbent, identification of key parameters 

governing performance, and prediction of lifetimes and transient responses of candidate adsorbents 

under fuel processing conditions.

• Fabricate new structured forms of ZnO which optimize reactivity while minimizing the weight of ZnO 

required.

• Complete experimental work to verify design parameters and to evaluate process performance in both 

a microreactor test system and an integrated fuel processing system.
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

108

Accomplishments

• Fabricated two new structured forms of ZnO, a ZnO-coated cordierite monolith and a self-supporting 

ZnO layer in a spiral microchannel configuration.

• Demonstrated that the self-supporting ZnO layer is capable of reducing the H2S concentration in a 

simulated reformate stream from 10-30 ppm to less than 1 ppm.

Future Directions

• Evaluate the performance of the new structured forms of ZnO in a 1000-h test in a microreactor fuel 

reformer.

• Define better the H2S tolerance for the fuel processor and fuel cell catalysts.

• Identify new/alternative technologies for H2S removal.

Introduction

Even with the lower sulfur content proposed for 

gasolines in 2004 of 30 ppm average and 80 ppm 

maximum (by weight), reformate produced from 

these gasolines by autothermal reforming for use 

with PEMFC will contain 3-8 ppm of H2S. H2S is 

known to poison many catalysts, often at a 

concentration of 1 ppm or less. For example, an inlet 

H2S concentration of 50 ppb is recommended for 

copper-zinc oxide water-gas shift catalysts being 

considered for use in fuel processing systems by 

some developers. It has been reported (1) that H2S at 

a concentration of 1 ppm irreversibly poisons the Ptanode catalyst in the PEMFC.

In FY1999, we conducted a review of the 

technical and patent literature to identify candidate 

technologies for removing H2S from reformate under 

fuel processing conditions. We identified adsorption 

with chemical reaction as the most promising 

technology. Based on thermodynamic equilibrium 

calculations, we identified candidate metals and 

metal oxides that are capable of reducing the 

concentration of H2S to <1 ppm, are 

thermodynamically stable, and does not promote any 

undesirable chemical reactions under fuel processing 

conditions. Based on these criteria ZnO was selected 

as the initial test candidate. A sulfur removal unit, 

using commercially available ZnO pellets, was sized 

based on manufacturer-supplied operating 

parameters.

Approach

Our approach involves both modeling and 

experimental work. Thermodynamic equilibrium 

calculations are used to predict the optimal operating 

Figure 1. ZnO-coated cordierite monolith. ZnO weight 

loading is 40 wt%

Figure 2. Self-supporting ZnO layer in the form of a 

spiral microchannel configuration
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

109

conditions for candidate sulfur adsorbents, such as 

ZnO. Once the optimal operating conditions are 

defined, gas-solid reaction models, such as the 

shrinking core model, are used to define the optimal 

geometry of the adsorbent and to predict the 

performance of the adsorbent under processing 

conditions. Based on such modeling, a structured 

form of ZnO, such as a monolith or a microchannel 

configuration, consisting of a thin ZnO layer (~50-

100 μm) is predicted to be more reactive per unit 

volume and to use the ZnO more effectively than a 

cylindrical pellet form for removing H2S from 

reformate in a fuel processor.

Two new structured forms of ZnO have been 

fabricated including a ZnO-coated cordierite 

monolith (see Figure 1) and a self-supporting ZnO 

layer in a spiral microchannel configuration (see 

Figure 2). The ZnO-coated monolith was fabricated 

using a slurry coating process to deposit a ~50 μm 

thick layer of ZnO onto a cordierite monolith. The 

self-supporting ZnO microchannel was fabricated 

using a tape casting and rolling process to produce a 

ZnO layer with a thickness of ~100 μm.

The H2S removal efficiency of these new 

structured forms of ZnO was evaluated in a 

microreactor test system using a simulated reformate 

stream consisting of 10-100 ppm H2S. The removal 

efficiency was determined by measuring the H2S 

concentration in the effluent stream (using gas 

chromatography) as a function of the H2S 

concentration in the inlet stream, temperature, and 

gas hourly space velocity.

Results

The self-supporting ZnO layer in a spiral 

microchannel configuration was capable of reducing 

the H2S concentration in a simulated reformate 

stream from 10-30 ppm to less than 1 ppm at 400o

C 

and space velocities up to 8,000 h-1. For comparison, 

a space velocity of 700-2,000 h-1 is recommended for 

commercial ZnO in pellet form. It is estimated that 

the higher reactivity per unit volume of a structured 

form of ZnO will significantly reduce the weight and 

volume of the sulfur removal unit (by as much as 

~80%) compared to a unit that uses the pellet form as 

illustrated in Table 1.

The performance of the ZnO-coated cordierite 

monoliths produced in-house did not meet 

expectations due primarily to non-uniform coating of 

the monolith channels. Currently, we have contracted 

a commercial catalyst company with expertise in 

coating monoliths to produce a ZnO-coated monolith 

for evaluation.

Long-term performance of these new structured 

forms of ZnO will be tested in a microreactor fuel 

reformer for 1000-h and in an integrated fuel 

processing system being developed at ANL. 

Developmental work will continue to improve the 

reactivity and mechanical properties of these new 

structured forms. Experimental work will focus on 

better defining the H2S tolerance of various catalysts, 

such as reforming, water-gas shift, and selective CO 

oxidation, being developed for fuel processing. 

Conclusions

The ability of the self-supporting ZnO layer 

verifies that under the test conditions, the ZnO 

adsorbent bed can be used for the capture of H2S in 

gasoline reformate. Removal of H2S from the fuel 

gas is essential if the high performance of the fuel 

cell stack is to be maintained when operating the fuel 

cell system with sulfur-containing fuels. New 

Bed Form Space Velocity 1

 (hr-1) Sulfur Content of 

Gasoline (ppmw)

Lifetime of Bed 2

(gals of gasoline) Weight of Bed 3

 (kg)

Pellet 2000 30 8 x 104 31.0

Structured 5000 30 6 x 103 5.4

1

 Based on 20 kWe power.

2

 Based on 50% of stoichiometric loading of ZnO bed (~18 g S/g ZnO).

3

 Weight of bed is based on a density of 2 g/cm3 for both the pellets and the structured form.

Table 1. Comparison of the estimated size and weight of a sulfur removal unit using commercial ZnO pellets and a 

structured form of ZnO
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

110

adsorbents, as well as alternative technologies, will 

be investigated if new catalysts being developed 

require lower H2S concentrations than can be 

achieved with ZnO.

List of References

1. T. Zawodzinski, J. Bauman, T. Rockward, B. 

Mueller, T. Springer, F. Uribe, J. Valerio, and S. 

Gottesfeld: "R&D on Optimized Cell 

Performance for Operation on Reformate and 

Air," Presented at DOE Fuel Cells for 

Transportation National Laboratory R&D 

Meeting, June 23-25, 1999, Argonne, IL.

List of Presentations

1. T. Krause, D. Myers, and C. Pereira, "Reducing 

the Volume/Weight of the Fuel Post Processor for 

PEFC Power Systems", to be presented at the 

Fuel Cell 2000 Conference, October 30-

November 2, 2000, Portland, Oregon.

2. T. Krause, J.P. Kopasz, S. Ahmed, and M. 

Krumpelt, "Gasoline-How its Composition 

Effects Reforming and the Implication for 

Developing New Catalysts for On-board 

Reforming for Fuel Cell Vehicles", to be 

presented at the Annual Meeting of the American 

Institute of Chemical Engineers, November 12-

17, 2000, Los Angeles, California. 

List of Acronyms

ANL Argonne National Laboratory

PEMFC polymer electrolyte membrane fuel 

cell
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

111

D. The California Fuel Cell Partnership

Catherine Lentz, Program Manager (Primary Contact), Joseph J. Irvin, Communications Manager

California Fuel Cell Partnership

3300 Industrial Boulevard

West Sacramento, CA 95691

(916) 445-5047, fax: (916) 323-2393, email: clentz@arb.ca.gov

Website: www.drivingthefuture.org

DOE Program Manager: Peter Devlin

(202) 586-4905, fax: (202) 586-9811, e-mail: Peter.Devlin@ee.doe.gov

DOE Program Support: Larry S. Blair

(202) 586-0626, fax: (202) 586-9811, e-mail: Larry.Blair@ee.doe.gov

Objectives

• Demonstrate fuel cell technology by operating and testing vehicles on California’s roads.

• Demonstrate alternative fuel infrastructure technology.

• Explore the path to commercialization.

• Increase public awareness through a coordinated outreach plan.

Approach

• Adopt an organizational structure consisting of an Executive Committee, Project Group and 

communications group to provide a decision-making structure for developing a workplan, budget, 

headquarters facility, and outreach strategy under the following timetable:

- Phase I - through 1999, project development and planning, adding new partners, and preparing 

vehicle and refueling facilities;

- Phase II - 2000-2001, demonstrate cars and buses using hydrogen fuel; and

- Phase III - 2002-2003, demonstrate more cars and buses using hydrogen, methanol, gasoline or 

other fuels as determined by the Partnership.

Accomplishments

• Startup budget developed.

• Additional partners added.

• Plans for initial vehicle arrival and location determined.

• Commercialization study commissioned.

• Headquarters facility under construction.

• Hydrogen fueling structure identified and planned.

Future Directions

• Prepare for on-road fuel cell car and bus demonstrations; identify additional fueling sites and fuel 

choices; assess commercialization issues; and implement public outreach and education plans.
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

112

Introduction

The California Fuel Cell Partnership (CaFCP) is 

a path-breaking collaboration of auto companies, 

energy providers, fuel cell companies and 

government agencies that will place fuel cell electric 

vehicles on the road in California. The partners 

include companies and organizations from around 

the world: DaimlerChrysler, Ford, Honda, Hyundai, 

Nissan, and Volkswagen; Ballard Power Systems and 

International Fuel Cells; BP Amoco, Shell, and 

Texaco; and the California Air Resources Board, the 

California Energy Commission, the United States 

Department of Energy, the United States Department 

of Transportation and the South Coast Air Quality 

Management District. 

The partners are working together to achieve a 

common vision - preparing to commercialize the 

emerging vehicle technology of the 21st Century. 

The partnership will demonstrate fuel cell electric 

vehicles in California through 2003 under day-to-day 

driving conditions. Vehicle maintenance and fueling 

facilities will be constructed and used throughout the 

course of the project. The partnership will also 

explore the path to commercializing fuel cell electric 

vehicles by examining such issues as fuel 

infrastructure requirements, vehicle and fuel safety, 

market incentives, and consumer acceptance. The 

partnership will increase public awareness of fuel 

cell vehicle technology and the benefits it can offer 

through a number of outreach tools, including handson vehicle demonstrations and classroom curricula. 

Approach

While the CaFCP consists of a variety of 

industries and government agencies, all members 

have one thing in common: a desire to demonstrate 

fuel cell vehicle technology and promote its 

commercialization. It is an entirely voluntary 

commitment for all the partners, and one that 

depends on industry’s firm belief that this is a viable 

technology for the future.

Figure 1. The CaFCP Logo

Figure 2. California Governor Gray Davis Announces 

the Partnership at the State Capitol on April 20, 

1999

Figure 3. Partners "dig in" at the fuel cell facility 

groundbreaking ceremony on April 18, 2000

Figure 4. Architectural image of fuel cell facility, due to 

be completed in fall 2000
Fuels for Advanced CIDI Engines and Fuel Cells FY 2000 Progress Report

113

To demonstrate fuel cell technology, over 70 

vehicles will be driven on city streets and highways 

to test and demonstrate how they can meet the real 

transportation needs of California consumers. A 

fueling infrastructure for fuel cell vehicles will also 

be demonstrated, beginning with hydrogen fuel in the 

first stage of the project. Methanol and a gasoline 

cleaner than California RFG will be added in the 

later stages of the program. The partners also hope to 

promote the development of standards and 

specifications for fuels and the vehicle-fueling 

interface. This is a key benefit of bringing together 

vehicle manufacturers and fuel providers early in the 

process.

The partners plan to conduct joint 

commercialization studies that examine the 

consumer market, identify opportunities and 

challenges to using various fuels and infrastructure, 

and identify initiatives that can promote success. 

They plan to provide input to the development of 

codes and standards for vehicles, fuels and facilities. 

They will also promote the development of 

educational materials, safety procedures and 

emergency response training materials.

The partnership will take steps to broaden public 

awareness of fuel cell vehicles and their potential to 

provide environmental and vehicle performance 

benefits. This is a critical element of the program, as 

less than one in four Californians currently knows 

about fuel cells. The vehicles will be available for 

demonstrations in a variety of public venues. The 

Partnership’s Internet website 

(www.drivingthefuture.org) will provide educational 

information. 

The CaFCP is also constructing a facility in West 

Sacramento to be completed in fall 2000. This 

facility will house the partnership offices, a public 

gallery with fuel cell displays, and vehicle bays 

where the auto partners will house, service and 

maintain the fuel cell passenger cars. There will also 

be a hydrogen fuel station on-site. 

The state-of-the-art facility will meet all safety 

and technical requirements. But most importantly, it 

makes a statement about the nature of the 

partnership. This one-of-a-kind venture will bring 

together competitors under one roof as they work 

toward a common goal, and underscores their true 

commitment to making the project a success.

Conclusion

The first year of the project has produced 

remarkable progress given the unique dynamics of 

this partnership. A cooperative approach, focused on 

specific goals and the necessity for consensus-based 

decisions, has set the stage for success in the on-road 

demonstration phase, generating win-win benefits for 

the environment and the new economy.

Special Recognitions and Awards

1. Blue Sky Innovation AwardTM from CALSTART 

- the advanced transportation consortium - for 

taking early steps to create a fuel cell market by 

demonstrating fuel cell electric vehicles in 

California

List of Acronyms

CaFCP California Fuel Cell Partnership

RFG Reformulated Gasoline
This document highlights work sponsored by agencies of the U.S. Government. Neither the U.S.

Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied,

or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately

owned rights. Reference herein to any specific commercial product, process, or service by trade name,

trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the U.S. Government or any agency thereof. The views and opinions of authors

expressed herein do not necessarily state or reflect those of the U.S. Government or any agency thereof.

Printed on recycled paper
O FFICE OF T RANSPORTATION T ECHNOLOGIES

S ERIES OF

2000 A NNUAL P ROGRESS R EPORTS

• Vehicle Propulsion and Ancillary Subsystems

• Automotive Lightweight Materials

• Automotive Propulsion Materials

• Fuels for Advanced CIDI Engines and Fuel Cells

• SIDI Engine R&D

• Combustion and Emission Control for 

Advanced CIDI Engines

• Transportation Fuel Cell Power Systems 

• Vehicle Power Electronics and Electric Machines

• Advanced Technology Development 

(High-Power Battery)

• Exploratory Technology Research 

(High-Power Battery)

• Vehicle High-Power Energy Storage

• Electric Vehicle Batteries R&D

and Office of Advanced Automotive Technologies

FY2000 Program Highlights

www.ott.doe.gov/oaat

DOE/GO-102000-1150

Clean Energy

– for the –

21st Century