COORDINATING RESEARCH COUNCIL, INC. 

3650 MANSELL ROAD·SUITE 140·ALPHARETTA, GA 30022

CRC Report No. E-65-3 

FUEL PERMEATION FROM 

AUTOMOTIVE SYSTEMS: E0, E6, E10, 

E20 AND E85 

Final Report 

December, 2006
FUEL PERMEATION FROM AUTOMOTIVE 

 SYSTEMS: E0, E6, E10, E20 and E85 

Final Report 

CRC Project No. E-65-3 

December, 2006

Prepared by: 

Harold M. Haskew, P.E. 

Thomas F. Liberty 

Harold Haskew & Associates, Inc. 

Milford, Michigan 

Dennis McClement 

Automotive Testing Laboratories, Inc. 

Mesa, Arizona 
i

Table of Contents 

A. Background and Introduction....................................................................1 

B. Conclusions and Findings..........................................................................2 

C. General Discussion 

I. Test Program Overview.......................................................................3 

II. Project Scope – Fuel System Technology and Rig Construction ......5 

III. The Project and the Procedures........................................................10 

Fuels ..............................................................................................10 

Procedures for Measuring Steady-State Permeation and 

Determining Stabilization ................................................................14 

IV. Results 

Diurnal Performance – Technology.................................................16 

Diurnal Performance – Fuels ...........................................................18 

Data Summary..................................................................................21 

Rig and Fuel Type Diurnal Result Comparisons .............................23 

Steady-State Permeation Measurements..........................................24 

Steady-State Permeation Results by Rig..........................................29 

Speciation and Reactivity.................................................................31 

Statistical Analysis...........................................................................41 

D. The CRC E-65-3 Steering Committee Members ....................................49 

E. Appendix: The Ethanol Hang-up.............................................................50 
ii

List of Figures 

Figure No. Description Page No.

1 Testing Chronology................................................................................... 4 

2 Overall View – Rig 12 .............................................................................. 7 

3 Rig 1 Fuel Tank......................................................................................... 7 

4 Rig 2 Fuel Tank......................................................................................... 7 

5 Rig 11 Fuel Tank and Canister.................................................................. 8 

6 Rig 12 Fuel Tank....................................................................................... 9 

7 Rig 12 Fuel Tank and Canister.................................................................. 9 

8 Rig 14 Fuel Tank and Canister.................................................................. 9 

9 Liquid Fuel Aromatics ............................................................................ 13 

10 Constant-Temperature Test Cell ............................................................. 14 

11 Steady-State Results – Rig 2 - Fuel E0 - Test #6309.............................. 14 

12 Steady-State Results – Rig 12 – Fuel E6 – Test #6466........................... 15 

13 Diurnal Permeation Comparison – E0 Fuel ............................................ 16 

14 Diurnal Permeation Comparison – Non-Ethanol Fuel............................ 17 

15 Diurnal Emissions Comparison .............................................................. 17 

16 Diurnal Emissions Comparison – Rig 1.................................................. 18 

17 Diurnal Emissions Comparison – Rig 2.................................................. 18 

18 Diurnal Emissions Comparison – Rig 11................................................ 19 

19 Diurnal Emissions Comparison – Rig 12................................................ 20 

20 Diurnal Emissions Comparison – Rig 14................................................ 20 

21 Ethanol Impact – Stabilized Permeation - Rig 1..................................... 24 

22 Ethanol Impact – Stabilized Permeation - Rig 2..................................... 25 

23 Ethanol Impact – Stabilized Permeation - Rig 11................................... 26 

24 Ethanol Impact – Stabilized Permeation - Rig 12................................... 27 

25 Ethanol Impact – Stabilized Permeation - Rig 14................................... 28 

26 Stabilized Permeation Levels – Rig 1 ..................................................... 29 

27 Stabilized Permeation Levels – Rig 2 ..................................................... 29 

28 Stabilized Permeation Levels – Rig 11 ................................................... 30 

29 Stabilized Permeation Levels – Rig 12 ................................................... 30 

30 Stabilized Permeation Levels – Rig 14 ................................................... 30 

31 Diurnal & Steady-State Emissions & Reactivity vs Test Timing......42-43 

32 Diurnal & Steady-State Emissions & Reactivity vs Aromatics.........44-45 

33 Diurnal & Steady-State Emissions & Reactivity vs Ethanol .............46-47 

34 Diurnal Emissions vs Ethanol Content – Rig 1....................................... 48 

35 Ethanol Hang-up Rig 1 ........................................................................... 50 

36 Ethanol Hang-up Rig 2 ........................................................................... 51 

37 Ethanol Decay ......................................................................................... 53 
iii

List of Tables 

Table No. Description Page No.

1 Technology Groups and Corresponding Rig .....................................5 

2 Vehicle Information for the Test Rigs ...............................................5 

3 Test Fuel Inspections.................................................................. 10-11 

4 Test Fuel Composition Comparison – Paraffins ..............................12 

5 Test Fuel Composition Comparison – Olefins.................................12 

6 Test Fuel Composition Comparison – Aromatics............................13 

7 Detailed Permeation Emission Results ...................................... 21-23 

8 Diurnal Emissions Test Results .......................................................23 

9 Sample Speciation Results ......................................................... 32-36 

10 Fuel E0 Diurnal Permeate Reactivity Results..................................38 

11 Fuel E6 Diurnal Permeate Reactivity Results..................................39 

12 Fuel E6Hi Diurnal Permeate Reactivity Results..............................39 

13 Fuel E10 Diurnal Permeate Reactivity Results................................40 

14 Fuel E20 Diurnal Permeate Reactivity Results................................40 

15 Fuel E85 Diurnal Permeate Reactivity Results................................41 

16 2001 Toyota Tacoma Stabilization – Fuel E0............................ 50-51 

17 2000 Honda Odyssey Stabilization – Fuel E0 .................................52 
1

Fuel Permeation from Automotive Systems

E0, E6, E10, E20 and E85

A. Background and Introduction 

CRC Project E-65 investigated the effects of three different fuels on the permeation rates of the fuel 

systems from 10 different California vehicles, covering model years from 1978 to 2001. Results from this 

study were published in the report “Fuel Permeation from Automotive Systems” in September 2004, and 

are available on the websites of the Coordinating Research Council (CRC) and California Air Resources 

Board (CARB). Permeation is one of the three mechanisms identified as responsible for “evaporative 

emissions.” The other two are leaks (liquid and vapor) and fuel tank venting (canister losses). 

The original study vehicles were selected to represent a cross-section of the California in-use fleet as it 

existed in calendar year 2001, where pre-1983 model year (MY) vehicles were 10% of the registered fleet. 

The fuels tested in the original study included two oxygenated fuels: one with 11% MTBE and the other 

with 5.7% ethanol, and a non-oxygenated fuel for comparison. All the fuels had properties typical of 

California summer gasoline. The two oxygenated fuels contained 2.0 weight percent oxygen, the 

minimum oxygen content required by then-existing regulations for federal reformulated gasoline. 

Permeation increased in all vehicles when evaluated with the ethanol fuel. 

Based on the previous work, four issues were identified for further study in CRC Project E-65-3: 

1. Investigate the permeation characteristics of “near zero” evaporative emission control systems 

scheduled for California in MY 2004 and later. 

2. Determine if changes in ethanol content affect permeation levels. 

3. Establish the permeation effects of E85 (85 Volume% ethanol fuel) in a flexible fuel vehicle. 

4. Determine if permeation rates are sensitive to changes in aromatics content of the fuel. 

Harold Haskew & Associates, Inc. was selected as the prime contractor, with Automotive Testing 

Laboratories, Inc, in Mesa, AZ serving as the testing laboratory. It was agreed to re-commission Rigs 1 

and 2, the 2000 and 2001 MY systems from the E-65 project, and build three new test rigs, one 

representing a MY 2004 California “Near Zero” evap control vehicle, another representing the California 

“Zero Evap” control technology, and finally, a “Flexible-Fuel” vehicle, capable of operating on E85 or 

gasoline. 

Six test fuels were blended for this project: 

1. E0 – Non-oxygenated base fuel 

2. E6 – 5.7 Volume% ethanol fuel (2 Weight% oxygen) 

3. E6Hi – 5.7 Volume % ethanol fuel with increased aromatics content 

4. E10 – 10 Volume% ethanol fuel 

5. E20 – 20 Volume% ethanol fuel, and 

6. E85 – 85 Volume% ethanol fuel 

The testing for this project commenced in January of 2005, and continued through early August 2006. An 

Interim Report was made available in August of 2006 with the results from the E0, E6, E6Hi, E10, and 

E85 fuel testing results. This final report adds the results from the tests with the E20, or 20 volume 

percentage, ethanol fuel, as well as additional test results on the E0 fuel. 
2

These data represent a limited number of samples; care should be taken in extending these results to the 

fleet. 

B. Conclusions and Findings 

Conclusions: 

1. The low-level ethanol blends (E6, E6Hi, E10 and E20) increased permeation in all the vehicle systems 

and technologies tested, compared to the non-ethanol fuel (E0). These increases were statistically 

significant. 

2. The advanced technology LEV II and PZEV1

 systems (2004 MY) had much lower permeation 

emissions than the MY 2000-2001 enhanced evaporative systems. The zero evaporative emissions 

system (PZEV) had the smallest increase due to ethanol of all the vehicles tested. 

3. The high-level ethanol blend (E85) tested in the flexible fuel vehicle system had lower permeation 

emissions than the non-ethanol (E0) fuel. 

4. Diurnal permeation rates do not appear to increase between E6 and E10, but do appear to increase 

between E6 and E20; however, this increase is not statistically significant. 

5. The highest diurnal permeation rate for three of the five rigs (1, 2, and 12) tested was measured when 

these rigs were tested on the E20 fuel. The highest diurnal permeation rate for Rig 11 was recorded 

on the E6 fuel, while the highest diurnal permeation rate for Rig 14 was measured on the E10 fuel. 

6. Diurnal permeation emissions were lower on all four rigs tested with the higher-level aromatics fuel 

(E6Hi) versus the lower aromatics fuel (E6); however, this decrease was not statistically significant. 

7. Permeation rates with the E0 fuel at the start and the end of the test program were not significantly 

different on all five rigs, indicating that there was no shift in the permeation performance during the 

program. 

8. The average specific reactivities of the permeates from the low-level ethanol blends were significantly 

lower than those measured with the non-ethanol fuel (E0). There was no significant difference in the 

average specific reactivities within the low-level ethanol blends. 

Findings: 

1. The average diurnal permeation rate increased 347 mg/day (from 177 to 524 mg/day) when the E6 

fuel was substituted for the base non-ethanol E0 fuel. 

2. The average diurnal permeation rate increased 253 mg/day (from 177 to 430 mg/day) when the E6Hi 

fuel was substituted for the base non-ethanol E0 fuel. 

3. The average diurnal permeation rate increased 307 mg/day (from 177 to 484 mg/day) when the E10 

fuel was substituted for the base non-ethanol E0 fuel. 

4. The average diurnal permeation rate increased 385 mg/day (from 177 to 562 mg/day) when the E20 

fuel was substituted for the base non-ethanol E0 fuel. 

 

1

 Partial Zero Emission Vehicle – a vehicle with Super Ultra Low Exhaust Emission Levels (SULEV), and Zero Fuel 

Evaporative Emissions, certified to 150,000 mile and 15 year performance levels for the state of California 
3

5. On the “Flexible Fuel” Rig 14, the diurnal permeation rate increased 205 mg/day (from 261 to 466 

mg/day) from the base non-ethanol fuel (E0) rate when the E10 fuel was evaluated, increased 99 

mg/day (from 261 to 360 mg/day) from the base fuel rate when the E20 fuel was evaluated, but 

decreased 133 mg/day (from 261 to 128 mg/day) from the base fuel rate when the E85 fuel was 

evaluated. 

6. Relative to Rigs 1, 2 and 11, the “Zero Fuel Evaporative Emission” system (Rig 12) had a lower 

increase in permeation rate when the ethanol-containing fuels were evaluated. A 14 mg/day (from 36 

to 50) increase was measured with fuel E6, a 9 mg/day (from 36 to 45 mg/day) increase with fuel 

E6Hi, a 28 mg/day (from 36 to 64 mg/day) increase with fuel E10, and a 39 mg/day (from 36 to 75 

mg/day) increase with fuel E20. 

7. The average specific reactivity of the base E0 fuel permeate was 3.99, the highest of the five fuels 

evaluated. 

8. Average specific reactivity of the E6 fuel permeate was 3.00. 

9. Average specific reactivity of the E6Hi fuel permeate was 3.17. 

10. Average specific reactivity of the E10 fuel permeate was 2.94. 

11. Average specific reactivity of the E20 fuel permeate was 3.04. 

12. Average specific reactivity of the E85 fuel permeate was 2.73. 

13. Rig 11 permeate had the lowest specific reactivity of all the rigs on all the fuels tested. 

C. General Discussion 

I. Test Program Overview

The objective of this test program was to measure the permeation emissions of the newer (MY 2000 to 

2005) California vehicles with gasolines containing ethanol at various volume percent concentrations: 0, 

62, 10, 20 and, on one system, 85. At the 6% ethanol level, two fuels were blended to meet different 

targets of total aromatics (designated as “E6” and “E6Hi”) in order to evaluate the effect of this latter 

parameter on permeation. 

Five vehicle fuel systems were included in this project. Two California Enhanced Evap vehicles were 

carried over from the previous CRC E-65 project (the newest, Rigs 1 and 2). Three new rigs were 

constructed for this evaluation: a California LEV-II “near-zero” passenger car, a California PZEV Zero 

Evaporative Emission car, and a “Flexible-Fuel” vehicle capable of operation on gasoline, 85% ethanol, 

or any mixture in between. 

Stabilization - Once qualified as ready for test, each test rig was filled (100% of rated capacity) with the 

appropriate test fuel and stored in a room (“soak room”) at 105°F and periodically tested in a SHED3

 until 

the results indicated that stabilization of the permeation emissions was achieved. During this stabilization 

period, the fuel in each rig was circulated twice a week. Every seventh week all of the fuel in each rig 

was drained and replaced with fresh fuel. Once a week, each rig was removed from the soak room and 

 

2

 The federal minimum requirement for “reformulated” fuel was 2.0 weight percent oxygen. That correlates to 5.7 volume 

percent ethanol. For purposes of this report, we will refer to the 5.7 Volume% specification in its rounded off value of 6, as in 

E6. 

3

 SHED – Sealed Housing for Evaporative Determination 
4

placed in a hot soak SHED at a temperature of 105°F for three to five hours to estimate the current 

permeation rate. 

The constant-temperature tests to determine stabilization were performed in a 105°F hot-soak SHED for a 

three-hour test period, with the emissions measured during the last two hours (later tests on the lower 

permeation rigs were increased to a five hour period). All fixed-temperature (105°F) testing was 

performed in ATL’s SHED 14. Variable-temperature diurnal (65° to 105° to 65°F) testing was performed 

in ATL SHEDs 13 and 15. These three SHEDs are variable volume/variable temperature (VV/VT) 

equipment that can be operated in fixed or variable-temperature modes, and are referred to as VT-SHEDs. 

All the SHED’s and equipment used for this program were the same as were utilized for the original E-65 

program. 

Diurnal Evaluation - After the steady-state permeation rate of a rig was stabilized at 105°F, and 

approved by the CRC E-65-3 Steering Committee, it was evaluated for diurnal permeation performance 

using the California “Real-Time” 24-hour diurnal (65 to 105 to 65°F) emission test procedures. The fuel 

was drained from the rig, and a 40% fresh fill of the appropriate test fuel added. The rig was then placed 

in a VT-SHED, and the California diurnal procedure was performed over a period of 24 hours. Samples 

of the ambient air in the VT-SHED were taken at the start of the diurnal and at the end of the 24-hour test 

period for later hydrocarbon speciation analysis. The fuel tanks and the canisters were vented to the 

outside of the SHED to eliminate the possibility of the tank venting emissions being counted as 

permeation. Emission rates were calculated using the 2001 California certification test procedure, with 

the appropriate corrections for the ethanol in the permeate. 

Testing Chronology - Figure 1 on the following page shows the testing chronology to illustrate when the 

various rigs were being tested with the different fuels. Testing started on January 11, 2005, and the last 

diurnal test on Rig 2 was finished on August 10, 2006. The solid bar indicates the time interval for the 

steady-state and the diurnal evaluations. The interval between the solid bars indicates the decision period 

where the Steering Committee was considering approval of the data and authorizing the move to the next 

test fuel. 

Testing Chronology - Steady State and Diurnals

on Various Fuels

Date

Rig 1

Rig 14

Rig 12

Rig 11

Rig 2

E0

E85

E6 E6Hi E10

Jan 2005 March May July Sept Nov Jan 2006 March May July

E20 E0b

E0b E0c

Figure 1 
5

II. Project Scope – Fuel System Technology and Rig Construction

Fuel System Technology

Two enhanced evap rigs were carried over from the original E-65 project (Rigs 1 and 2), and three new 

rigs were added. The technologies are described in Tables 1 and 2. 

Table 1 

Table 2 

Vehicle Information for the Test Rigs 

Rig No. MY Make Model 

Odo 

(miles) Evap Family 

Tank Size 

(Gal) 

Tank 

Material VIN 

1 2001 Toyota Tacoma 15,460 1TYXE0095AE0 15.8 Metal 5TENL42N01Z718176 

2 2000 Honda Odyssey 119,495 YHNXE0130AAE 20 Plastic 2HKRL1852YH518467 

11 2004 Ford Taurus 29,973 4FMXR015GAK 18 Metal 1FAFP55S54G142635 

12 2004 Chrysler Sebring 6434 4CRXR0130GZA 16 Metal 1C3EL46J74N363042 

14 2005 Chevrolet Tahoe 4054 5GMXR0176820 26 Plastic 1GCEK13U85X7313EX 

The California Enhanced Evaporative Emission Control regulations were the first to require “real-time” 

diurnal emission measurements (three 24-hour day diurnals) and were phased in during the 1995 – 1998 

model year period. The pre-enhanced evap emission standard was 2.0 g/test, but the test consisted of a 

one hour simulated diurnal day, with the fuel tank locally heated from 60° to 84°F. Only one hour’s worth 

of vehicle evaporative emissions was measured during the diurnal, and that was with the vehicle at room 

temperature in a SHED, typically 72°F. The hot soak was measured in a SHED following an 11 mile 

drive at room temperature. The enhanced evap procedure measured the emissions from the vehicle in a 

variable-temperature SHED (VT-SHED), and the SHED ambient temperature was varied from 65° to 

105°F, exposing the entire vehicle and the fuel system component to the ambient temperature. The one 

hour hot soak was performed as before but after the running loss test, a one hour drive at 105°F. 

These regulations incorporated significant changes to the emissions certification test requirements, and 

produced corresponding changes in the vehicle materials and hardware used by the automobile 

manufacturers. The emission control system useful life and warranty period were extended to 10 years or 

100,000 miles. Two-day and three-day diurnal tests were required, as was the measurement of “runningloss” emissions. The allowable limits for the highest one day of diurnal emissions for the three-day test, 

plus the one hour of hot soak following the drive are 2.0 g/test, or 2.5 g/test for vehicles with fuel tanks 

rated at 30 or more gallons. Light-duty trucks are allowed slightly higher limits. 

California’s Near Zero (LEV II) requirements dropped the allowable limits for passenger cars by 75% to 

0.5 g/test for the three-day diurnal, and to 0.65 g/test for the two-day test. Phase-in started with 40% of 

Technology Groups and Corresponding Rig

Enhanced Evaporative Emissions Rigs 1 & 2 

California Near-Zero (LEV II) Rig 11 

California PZEV (Zero Fuel Evaporative Emission) Rig 12 

Flexible Fuel Vehicle (FFV) Rig 14 
6

production in model year 2004, 80% in 2005, and 100% in 2006. Significant improvements in permeation 

performance and tank vapor control (carbon canister design) were required. 

California’s PZEV vehicles are developed and certified to have “Zero” fuel evaporative emissions where 

zero is defined as less than 0.0 grams per test when measured on California’s evaporative emission test 

procedures. This is agreed to be less than 54 milligrams per test (highest of the 3 diurnal days + one hour 

high temperature hot soak). This standard requires the highest level of emission control in every aspect of 

the vehicle’s fuel and vapor control system, both in performance and durability. 

Flexible Fuel Vehicle is a vehicle capable of performing on gasoline or a high percentage of ethanol 

(85%), or any mixture of the two. The evaporative emission standards are the enhanced emission 

standards with certain test procedure modifications. Sensors (or in later versions, software) are used to 

detect the mixture in the fuel system and make the appropriate adjustments for the engine and emission 

control system. This is performed automatically, and no action is required by the vehicle operator. 

Flexible fuel vehicles are certified to meet the evaporative emission performance limits on gasoline, or the 

worst combination of the ethanol/gasoline mixture (currently thought to be 10% ethanol). 

Test Rig Construction

Fuel system test “rigs” are used in the automotive development process to isolate the fuel system’s 

contribution to the emissions. Since tires, adhesives, paint and vinyl trim can also emit hydrocarbons, 

they need to be removed to provide a better chance of properly identifying the fuel-related emissions. 

Isolating the fuel system components on a “rig” is the appropriate choice. 

Refueling vapor controls are commonly developed in the automotive industry using rigs, or “test bucks”, 

but they feature only the tank and canister system, with the carbon canister located close to the tank. This 

project included the fuel and vapor lines, and their chassis-to-engine connection hoses at the front of the 

vehicle. All the fuel system components (with the exception of the engine mounted injectors and hoses4) 

that could contribute to permeation losses were kept in the original spatial relationship. This meant that 

the rigs were almost as long as the vehicles. For system integrity, all components were removed and 

remounted on the rigs without any fuel or vapor line disconnections. 

In the original E-65 project, the vehicle was sacrificed to remove the fuel system components, and the 

remaining body parts and pieces sold as scrap. Our previous experience indicated that the fuel system on 

the newer vehicles (mid-90s and later) could be removed from the vehicle without catastrophic surgery. 

 

The test rig frame was constructed of 1.5” square aluminum tube, with metal caster wheels at the four 

corners. A photo of Rig 12 appears in Figure 2 to show a typical configuration. There is a lot of empty 

space required to keep all of the fuel system components in their x, y, and z orientation as present in the 

vehicle. 

 

4

 It was decided in the original E-65 project to eliminate the engine-mounted fuel system components (including carburetors 

and injectors) to avoid the compromising contributions of leaks and vapor losses. The investigators wanted to identify the 

contribution of permeation, not leaks. The fuel supply lines and hoses, and the return components, if fitted, are present on the 

rigs, with terminations where the engine connections are made. This practice was continued for the current project. 
7

Enhanced Evaporative Emissions Technology – Rigs 1 & 2

Rigs 1 and 2 were carry-over systems from the previous CRC fuel permeation project reported in 

September of 2004, and photos of the fuel tank end of the rigs are shown here 

Rig 1 was fabricated to evaluate the permeation performance of the metal fuel tank system from a 2001 

MY Toyota Tacoma pick-up truck, and is shown in Figure 3 above. The metal tank was coated with a 

black anti-rust paint with a short metal fill-pipe that ran to the side of the truck body. The carbon canister 

and purge control solenoid for this pre-ORVR5

 system was located in the left front side of the engine 

compartment.

 

5

 ORVR – On-board Refueling Vapor Recovery, an emission control configuration with components and function to capture 

the refueling vapors and store them for later combustion. The Toyota pick-up was not required by the California regulatory 

roll-out requirements to have such a system until MY 2003. 

Figure 3 - Rig 1 Fuel Tank 

Figure 2 - Overall View - Rig 12 

Figure 4 - Rig 2 Fuel Tank 
8

Rig 2’s (2002 MY Honda Odyssey, a light-duty passenger van) fuel system features a large (20 gallon 

capacity) plastic fuel tank of multi-layer blow-molded construction for a high degree of permeation 

control (Figure 4). The carbon canister for this pre-ORVR system is located in the vehicle’s under-body 

close to the position of the driver’s seat. 

Both of these rigs were certified to the California enhanced evaporative emission standard of 2.0 grams 

per test for the three-day diurnal + hot soak, and 2.5 grams per test for the two-day diurnal + hot soak. 

Rig 11 (Figure 5) was created from the fuel system components of a 2004 MY Ford Taurus sedan. The 

vehicle was purchased from a California dealer and driven to the laboratory in Mesa AZ, where after 

inspection and approval, the fuel system was removed and mounted in the aluminum frame to become a 

“rig.” The fuel tank was of steel construction and had a rated capacity of 18 gallons. The fuel tank was 

located near the rear seat position on the vehicle, and the on-board refueling vapor recovery (ORVR) 

canister was positioned further aft, as shown in Figure 5. 

Figure 5 - Rig 11 Fuel Tank and Canister 
9

Rig 12 (Figures 6 & 7) was fabricated using the 

fuel system components from a 2005 MY Chrysler 

Sebring sedan. It also featured a steel fuel tank and a 

carbon canister mounted adjacent to the tank. It was 

certified as an on-board refueling vapor recovery 

system (ORVR). 

Rig 14 (Figure 8) featured the fuel system components from a 2005 MY Chevrolet Tahoe SUV. It was 

certified to be a “Flexible-Fuel” system, which means it can operate on gasoline or E85, or any mixture of 

the two. The Tahoe has a 26 gallon multi-layer “plastic” fuel tank, and a close-mounted carbon canister 

for tank vapor control. It is also an ORVR design system. 

Figure 6 - Rig 12 Fuel Tank 

Figure 7 - Rig 12 Fuel Tank and Canister

Figure 8 - Rig 14 Fuel Tank and Canister 
10

III. The Project and Procedures

Fuels

Six test fuels were blended for the CRC E-65-3 follow-up project. All of the low-level ethanol blends 

(i.e., E0-E20) were made from California blending components and were targeted at California summer 

fuel characteristics with vapor pressures targeted at 7.0 psi. The gasoline used to blend the E85 fuel was a 

high vapor pressure conventional gasoline, but butane still had to be added to the blend to approach the 

target 7.0 psi vapor pressure. These fuels were: 

Tag Description 

E0 Non-oxygenated base fuel 

E6 5.7 Volume% ethanol fuel (2 Weight% oxygen) 

E6Hi 5.7 Volume% ethanol fuel with increased aromatics content 

E10 10 Volume% ethanol fuel 

E20 20 Volume% ethanol fuel 

E85 85 Volume% ethanol fuel 

The basic inspections of the six test fuels are shown in Table 3. 

Table 3 

Test Fuel Inspections 

Inspection Units E0 E6 E6Hi E10 E20 E85 

API Gravity °API 61.4 58.8 52.3 58.3 55.4 48.6 

Relative Density 60/60°F 0.7334 0.7434 0.7699 0.7455 0.7572 0.7855 

DVPE psi 7.00 7.25 7.19 7.17 7.06 6.80 

Oxygenates--D 4815 

MTBE vol % 0.01 0.00 0.00 0.00 0.00 0.00 

ETBE vol % 0.00 0.00 0.00 0.00 0.12 0.00 

EtOH vol % 0.00 6.02 6.28 10.29 19.82 84.69 

MeOH vol % 0.00 0.00 0.00 0.00 0.00 0.83 

O2 wt % 0.00 2.23 2.25 3.81 7.23 29.73 

FIAM Corrected--D 1319 

Aromatics vol% 22.57 26.79 41.47 26.03 26.18 3.86 

Olefins vol% 10.70 4.91 3.32 4.77 4.85 1.57 

Saturates vol% 66.73 62.24 50.45 58.83 49.23 9.82 

Oxygenates vol% 0.00 6.02 6.28 10.31 19.94 85.21 

Aromatics--D 5580 

Benzene vol% 0.41 0.55 0.43 0.51 0.70 0.17 

Toluene vol% 5.26 6.84 5.25 6.50 8.31 0.67 

Ethylbenzene vol% 1.08 1.46 1.13 1.39 1.71 0.15 

p/m-Xylene vol% 4.67 5.38 4.21 5.13 6.01 0.59 

o-Xylene vol% 1.67 1.98 1.81 1.89 2.14 0.22 

C9+ vol% 8.86 10.01 25.71 9.52 7.55 2.02 

Total vol% 21.96 26.22 38.55 24.93 26.42 3.82 
11

Table 3 (Continued) 

Test Fuel Inspections 

Inspection Units E0 E6 E6Hi E10 E20 E85 

D 86 Distillation 

 IBP °F 101.1 108.9 98.0 107.7 112.1 116.8 

 5% Evaporated °F 123.2 125.8 124.8 127.2 130.6 153.5 

 10% Evaporated °F 134.5 130.7 132.1 132.1 135.8 164.0 

 20% Evaporated °F 148.5 136.8 142.4 138.2 143.4 168.7 

 30% Evaporated °F 165.0 144.8 159.0 144.7 149.7 170.4 

 40% Evaporated °F 186.2 175.8 206.3 150.8 155.1 171.2 

 50% Evaporated °F 209.5 202.0 241.9 182.6 159.6 171.5 

 60% Evaporated °F 231.1 225.6 274.0 221.8 165.9 171.8 

 70% Evaporated °F 251.2 249.3 302.8 246.0 234.6 172.0 

 80% Evaporated °F 273.4 275.7 324.5 273.3 257.9 172.4 

 90% Evaporated °F 305.6 309.9 345.3 309.4 291.1 173.1 

 95% Evaporated °F 330.6 335.9 363.2 335.7 312.4 174.1 

 EP °F 389.9 380.4 411.4 378.3 352.0 297.4 

Recovery vol % 97.7 97.6 97.2 98.0 97.3 97.1 

Residue vol % 1.0 1.0 1.2 1.1 1.0 1.9 

Loss vol % 1.3 1.4 1.5 0.8 1.7 1.0 

 

Karl Fischer Water wt % - - - - - 0.42 

Additional Inspections 

Fuel Units E0 E6 E6Hi E10 E20 E85 

Gum 

Unwashed mg/100ml 20 16 18 17 19 9 

Washed mg/100ml 1 1 0 0 0 0 

 

Peroxide Number ppm <1 <1 <1 1.0 <1 4.4 

 

Induction Period Hr 24 24 24 24 24 24 

Potential Gum 

Unwashed mg/100ml 22 22 24 20 19 7 

Washed mg/100ml 0 0 0 0 0 2 

 

Research ON 90.5 92.1 96.2 94.5 98.7 105.8 

Motor ON 83.2 84.2 86.2 86.4 86.6 89.2 

(R+M)/2 86.9 88.2 91.2 90.5 92.7 97.5 
12

Complete speciation analyses of the fuels were also furnished, and the files are available with the 

following names: 

Tag File Name 

E0 E0-FR41677-LDR 

E6 E6-FR41678-LDR 

E6Hi E6High-FR41785-LDR 

E10 E10-FR41681-LDR 

E20 E20-FR43560-LD 

E85 E85-FR42011-LDR 

Compositions of the E0 and low level ethanol blends are presented by hydrocarbon type and carbon 

number in Tables 4, 5 and 6 below. 

Table 4 

Test Fuel Composition Comparison - Paraffins

Paraffins by Volume % 

Fuel C3- C4 C5 C6 C7 C8 C9 C10 C11 C12+ 

E0 0.419 18.789 10.322 6.783 14.017 4.341 1.618 0.502 0.068 

E6 0.163 14.938 17.492 8.016 9.732 3.613 0.919 0.442 0.031 

E6Hi 1.609 10.58 13.061 6.091 7.394 2.808 1.343 0.424 0.126 

E10 0.150 14.22 16.649 7.753 9.15 3.412 0.865 0.417 0.027 

E20 0.876 9.202 12.752 8.295 9.066 1.585 0.446 0.049 0.007 

Table 5 

Test Fuel Composition Comparison - Olefins

Olefins by Volume % 

Fuel C3- C4 C5 C6 C7 C8 C9 C10 C11 C12+ 

E0 0.029 0.101 2.025 5.126 0.579 0.514 0.013 

E6 0.013 0.914 1.613 0.771 0.347 0.007 

E6Hi 0.008 0.66 1.197 0.595 0.273 0.007 

E10 0.011 0.876 1.509 0.727 0.324 0.007 

E20 0.016 0.004 0.669 2.040 0.873 0.448 
13

Table 6 

Test Fuel Composition Comparison – Aromatics 

Aromatics by Volume % 

Fuel C3- C4 C5 C6 C7 C8 C9 C10 C11 C12+ 

E0 0.448 5.286 7.971 6.443 2.696 0.594 0.087 

E6 0.6 6.875 9.249 7.055 2.928 0.568 0.048 

E6Hi 0.454 5.25 7.603 16.538 9.101 1.724 0.216 

E10 0.569 6.502 8.715 6.650 2.753 0.523 0.045 

E20 0.693 8.250 9.878 5.978 1.505 0.146 0.042 

Figure 9 illustrates the distribution of the aromatics content in the base non-ethanol fuel and the four lowethanol concentration fuels. The aromatics total and the distribution of the aromatics by carbon number 

are similar for fuels E0, E6, E10 and E20. The high aromatics fuel (E6Hi) has 39% aromatics compared 

to the 22-26% for the other three, and the concentration of the higher carbon number molecules (C9-C11) 

is much higher. 

Figure 9 

6

7

8

9

10

11

12 E0

E6

E10

E20

E6Hi

0

2

4

6

8

10

12

14

16

18

Volume

Percent

Carbon Number

Fuel

Liquid Fuel Aromatics - Volume Percent

Total Aromatics = 22%

39%

25%

26%

26%
14

Procedures for Measuring Steady-State Permeation and Determining Stabilization

Permeation is a molecular migration of the fuel through the elastomeric materials of the vehicle fuel 

system. The test plan anticipated that time would be required for stabilization to occur after a new fuel 

composition was introduced. This would be possibly six to twelve weeks at the 105°F stabilization 

temperature. The vehicle fuel tank was filled to 100% of its rated capacity for stabilization, and the 

contents circulated through the liquid and vapor system twice a week for a 20 minute period to keep the 

liquid and vapor in the hoses “fresh.” The canister was purged by drawing ambient air through the 

canister bed for a period of 20 minutes, twice a week, using a vacuum pump. 

The rigs were kept in a constant-temperature 

test cell at 105°F during the stabilization period. 

A photo of the cell occupied by various rigs is 

shown in Figure 10. 

Once each week the rig was moved from the 

“soak room” to the SHED for the permeation 

determination. The steady-state test involved 

placing the rig in the pre-heated 105°F SHED, 

connecting the tank and canister vent hoses to a 

bulk-head fitting in the SHED wall so that any 

tank or canister venting losses would not be 

measured as permeation, closing the door and 

allowing the SHED to come back to a to a 

stabilized temperature. 

Either a three- or five-hour test was conducted to 

measure permeation. The three-hour test was used for 

the three higher permeation level rigs, 1, 2 and 14. The 

five-hour test was used for rigs 11 and 12 for tests 

starting in June 2005 on fuels E6 and later. 

 

A sample plot of the steady-state test results is shown in 

Figure 11. The horizontal axis is time, in minutes, and 

the vertical axis is the mass (in milligrams) as measured 

in the SHED using the conventional SHED test 

procedure and equipment. The mass was calculated 

every 30 seconds and the results are plotted in Figure 

11. The first hour of the test is shown in the red dots, 

and the last two hours in green. The trendline function 

in Microsoft EXCEL® was used to calculate the rate of 

change in the SHED mass over the second and third 

hours (the green data). This slope became the estimate of 

the steady-state permeation rate in mg/hour. 

Steady State Results - Rig 2 Fuel E0 Test #6309

y = 0.719x + 214.835

200

250

300

350

400

450

0 60 120 180

Time in Minutes

SHED Mass in milligrams

mg/hr = 43.14

Figure 10 - Constant-Temperature Test Cell 

Figure 11 
15

The five-hour test adopted for the E6 stabilization tests during June of 2005 was an attempt to improve 

the precision of the measurement on these really low permeation rigs (e.g., 3 mg per hour). The five-hour 

test used the last four hours of the five-hour test for the permeation measurement. An example of the 

five-hour test results is shown in Figure 12. 

This plot illustrates the conditions that are created when 

one tries to measure 3 mg/hour in a 2100 ft3 enclosure. 

The SHED concentration, as determined by the FID 

went from 7.105 ppm at 60 minutes to 7.551 ppm at the 

300 minute mark, an increase of one half of a part per 

million (ppm) carbon in the enclosure over the four hour 

period. The mass in the SHED rose from 223 mg to 237 

mg during the four hour period. That the SHED can 

measure these differences, and identify them with the 

precision and resolution shown in Figure 12, would 

have been thought impossible just a few years ago. A 

smaller SHED volume (a mini-SHED) would increase 

the concentration change, and help with the precision, 

but these rigs were almost the same length as the 

vehicles they represented – a significantly smaller 

SHED was not possible. 

The plot format used here was also an excellent quality check on the data, and could point out leaks and 

test irregularities. The mass as measured by the FID had to be corrected for the misidentification of the 

ethanol (if ethanol was present). 

Stabilization was established when the four-week average of the permeation rate reversed in trend, i.e., 

when the average rate either increased or decreased over the previous trend’s rate. A recommendation was 

made by the program administrator in a weekly status report, and the Steering Committee approved (or 

disapproved) the recommendation. The time required for stabilization ranged from five weeks (Rig 14, 

Fuel E0) to 13 weeks for Rig 12, Fuel E6. Once declared stable, the rig was drained and prepped for the 

diurnal measurement. 

IV. Results

This section of the report begins with the details of the diurnal and steady-state test results. Following 

that, the hydrocarbon speciation of the diurnal measurements is addressed and the average specific 

reactivities of the permeates are calculated for the various technologies on the various fuels. 

Diurnal6

 performance measurements are emphasized in this permeation study because the ultimate use of 

this information is to improve the ability of emissions inventory models to estimate the contribution of 

motor vehicles to air pollution. A portion of this report is also devoted to the steady-state results, as it is 

hoped that the steady-state (constant temperature) results can one day be used to predict the diurnal 

emission performance. 

 

6

 “Diurnal”, occurring daily, or having a daily cycle 

Steady State Results - Rig 12 - Fuel E6

Test #6466

y = 0.0551x + 220.26

215

220

225

230

235

240

0 60 120 180 240 300

Time in Minutes

SHED Mass in milligrams

mg/hr = 3.31

Figure 12 
16

Diurnal Performance – Technology

The diurnal permeation performance of the 

different emission technologies tested in this 

study is summarized in Figure 13. These results 

were obtained when the rigs were tested with 

the base fuel, E0. On the left are the two 

vertical bars representing the diurnal permeation 

performance for the two enhanced evap Rigs 1 

and 2. 

The third bar from the left shows the 39 mg/day 

level of Rig 11, the LEV II, or California NearZero vehicle fuel system. The fourth bar is the 

36 mg/day performance of the California “Zero 

Fuel Emission” vehicle. To qualify as a Zero 

Fuel Evaporative Emission system, this vehicle 

is certified to have less than 54 mg/day 

evaporative emissions, including the canister 

loss and a one hour hot soak. Finally, the last 

bar is the permeation performance of the 

“flexible fuel” Chevrolet Tahoe. 

While the 458 mg/day permeation result on fuel 

E0 on Rig 2 seems high compared to the 91 

mg/day from Rig 1, it is lower than previously measured with the plastic tank systems on the non-ethanol 

fuel in the E-65 project, one of which measured over 11,000 mg/day. The expanded plot shown in Figure 

14 includes some of the technologies from the previous CRC E-65 report7

 “Fuel Permeation from 

Automotive Systems.” The blue bars on the left (Rigs 1-6) are the permeation results on the nonoxygenated fuel, “Fuel C” measured in the previous program. The red oval highlights the performance 

level of Rigs 1 and 2 on Fuel C and the current program’s Fuel E0. 

 

7

 Coordinating Research Council (CRC) web site, http://www.crcao.org 

Figure 13 

Diurnal Permeation Comparison - E0 Fuel

Various Technologies

91

458

39 36

261

0

50

100

150

200

250

300

350

400

450

500

Diurnal Permeation - mg/day

Enhanced LEV II FLEX PZEV

 Evap

Rig 1 Rig 2 Rig 14 Rig 11 Rig 12
17

A plot showing the diurnal results for the five test rigs on the fuels tested in this program is shown in 

Figure 15.

Figure 15 

Diurnal Emissions Comparison

0

200

400

600

800

1000

1200

1400

1600

1800

Rig Number

Diurnal Emissions - mg/day

Fuel E0

Fuel E6

Fuel E6Hi

Fuel E10

Fuel E85

Fuel E20

Rig 1 Rig 2 Rig 11 Rig 12 Rig 14

When replicate tests are run, the average is shown.

Diurnal Permeation Comparison - Non-Ethanol Fuel

Various Technolgies Tests

1225

341 253

91

596

458

39 36

261

0

500

1000

1500

2000

2500

3000

3500

4000

Diurnal Permeation - mg/day

4055 12762

Enhanced LEV II FLEX PZEV Evap

Basic Evap - Plastic Tank ORVR

Rig 6 Rig 5 Rig 4 Rig 3 Rig 2 Rig 1 Rig 11 Rig 12 Rig 14

E-65 Fuel "C"

E-65-3 Fuel E0

Figure 14 
18

Diurnal Performance - Fuels

Rig 1 - The diurnal emissions measured for Rig 1, 

the MY 2001 enhanced evap system, ranged from 

91 mg/day on the base fuel (E0) to 508 mg/day on 

the E20 fuel. Figure 16 compares the results for the 

five fuels tested. Where multiple tests were run, 

such as those for the E0 and E6 fuels, the average 

results are presented. (Table 7 at the end of this 

section details the actual tests used.) The 

component on the top of each bar illustrates the 

ethanol fraction of the total emissions. For 

example, the E6 test total of 475 mg/day had 149 

mg/day of ethanol. A very small amount of the E0 

test (1 mg/day) was ethanol, even though there was 

no ethanol in the fuel, apparently a “hang-up” from 

the rig’s previous experience on ethanol fuel. The 

issue of the “hang-up” and the concerns thereof is 

discussed in the appendix of this report. 

The diurnal permeation emissions with the E6 fuel increased by 384 mg/day compared to E0. The diurnal 

results with the E6Hi (high aromatics) fuel were 114 mg/day lower than the E6 fuel, with lower (91 

mg/day compared to 149 mg/day) ethanol in the permeate. The permeation with the E10 fuel was almost 

identical compared to the E6 fuel (7 mg/day lower), but with higher ethanol in the results. The E20 

permeation was the highest measured on this rig. 

Rig 2 - Rig 2, another enhanced evap system (2000 

MY), also had substantial increases in permeation 

when tested with the ethanol-containing fuels, as 

shown in Figure 17. The permeation increased 

from 458 mg/day with the base (E0) fuel to 1765 

mg/day with the E20 fuel. The ethanol fraction 

was about 400 to 600 mg/day for the four ethanol 

blends evaluated. The permeation for the E10 fuel 

was 125 mg/day lower than for the E6 fuel. The 

higher aromatics fuel, E6Hi, showed a 199 mg/day 

lower permeation than the E6 fuel. The E20 

permeation was also the highest measured on this 

rig. 

Diurnal Emissions Comparison - Rig 1

0

100

200

300

400

500

600

Diurnal Emissions - mg/day

E0 E10 E6 E6Hi

Pink Bar is Ethanol 

91

475

361

468

1

149

91

184

E20

231

508

Figure 16 

Diurnal Emissions Comparison - Rig 2

0

200

400

600

800

1000

1200

1400

1600

1800

2000

Diurnal Emissions - mg/day

E0 E10 E6 E6Hi

Pink Bar is Ethanol 

458

1426

1227

1301

5

417

391

422

E20

623

1765

Figure 17 
19

Rig 11 - The results for Rig 11, shown in Figure 

18, indicate that all the ethanol blends increased the 

permeation rate compared to the base (E0) fuel. 

The permeation rate for the E6 fuel was 105 

mg/day higher than for the E0 fuel. The higher 

aromatics fuel, E6Hi, had 55 mg/day lower 

permeation than the E6 fuel. The E10 fuel had 21 

mg/day lower permeation than the E6 fuel, and the 

E20 fuel was 42 mg/day lower than the E6 fuel. 

This rig and Rig 14 were different in their ethanol 

response than Rigs 1, 2 and 12, in that they had 

lower permeation on the E20 fuel than the E6 or 

E10 fuels. Rig 11 also had the lowest specific 

reactivity over all the fuels tested, as is described in 

a later section of this report on speciation and 

reactivity. 

Rig 12 - When tested on the base (E0) non-ethanol 

fuel, this rig was measured at 36 mg/day. Rig 12 

was found to have less than 4 mg/day ethanol “hangup” when tested with the E0 fuel. The diurnal 

permeation increased when this rig was tested on 

any of the ethanol-containing fuels, as shown in 

Figure 19. The permeation for the E6 fuel was 14 

mg/day greater than the E0 fuel. The permeation for 

the E6Hi fuel was 5 mg/day lower than the E6 fuel. 

This was the only rig that demonstrated a greater 

diurnal permeation for the E10 fuel vs. the E6 fuel, 

14 mg/day higher. The highest permeation measured 

was on the E20 fuel, at 75 mg/day. 

Diurnal Emissions Comparison - Rig 11

0

20

40

60

80

100

120

140

160

Diurnal Emissions - mg/day

E0 E10 E6 E6Hi

Pink Bar is Ethanol 

39

144

89

123

2

20

19

34

E20

102

38

Figure 18 

Diurnal Emissions Comparison - Rig 12

0

10

20

30

40

50

60

70

80

Diurnal Emissions - mg/day

E0 E10 E6 E6Hi

Pink Bar is Ethanol 

36

50

45

64

4

13

15

24

75

31

E20

Figure 19 
20

Rig 14 - A “FlexFuel” system evaluation was 

included in this project. Flexible fuel vehicles are 

designed and developed to perform on fuels 

containing just gasoline, or up to 85% ethanol fuel, 

and any combination in between.

Diurnal emissions were measured on four fuels, 

with the average results shown in Figure 20. The 

permeation emissions were nearly doubled (466 vs. 

261 mg/day) with the E10 fuel, compared to the E0 

fuel, but were approximately halved (128 vs. 261 

mg/day) when the E85 fuel was tested. Like Rig 

11, the permeation was lower on the E20 fuel 

compared to the E10 results. The ethanol was 139 

mg/day when tested with the E10 fuel, similar in its 

fraction of the permeation total to the results from 

the other rigs evaluated. The ethanol of the E85 

test results was 76 mg/day, almost 2/3rd of the total 

permeation. It seems reasonable that if the fuel is 

almost all ethanol, the permeate ought to be mostly 

ethanol.

Figure 20 

Diurnal Emissions Comparison - Rig 14

0

100

200

300

400

500

Diurnal Emissions - mg/day

E0 E10 E20

Pink Bar is Ethanol 

261

466

128

9

139

76

E85

360

111
21

Data Summary

A comprehensive table, Table 7, follows with the diurnal permeation results for each vehicle and fuel, as 

well as the steady-state permeation results, the ratio of the diurnal result to the steady-state result, and the 

specific reactivity of the permeate calculated for the individual diurnal tests. 

Table 7 

Detailed Permeation Emission Results 

Rig #1 - 2001 Toyota Tacoma 

Fuel 

4-week Avg. 

mg/hour 

Diurnal Test ID 

mg/day Ratio 

Specific 

Reactivity 

g O3/g VOC 

E0 7.04 6389 83.9 11.9 4.31 

E0b 8.57 6886 97.2 11.4 4.15 

Avg. = 7.80 90.6 11.7 4.23 

 

E6 25.6 6471 417.1 16.3 3.05 

 6479 533.3 20.8 3.08 

Avg. = 475.2 18.6 3.07 

 

E6Hi 29.2 6571 360.9 12.4 3.30 

 

E10 35.2 6665 467.8 13.3 3.03 

 

E20 43.4 6806 508.1 11.7 3.20 

 

Rig #2 - 2000 Honda Odyssey 

Fuel 

4-week Avg. 

mg/hour 

Diurnal Test ID 

mg/day Ratio 

Specific 

Reactivity 

g O3/g VOC 

 

E0 42.5 6390 463.3 10.9 4.26 

E0b 33.7 6913 451.6 13.3 4.16 

Avg. = 38.1 457.5 12.1 4.21 

 

E6 97.7 6481 1426.0 14.6 3.54 

 

E6Hi 88.9 6570 1227.0 13.8 3.66 

E10 101.5 6673 1300.6 12.8 3.45 

 

E20 148.8 6816 1765.1 11.9 3.32 
22

Table 7 (cont) 

Detailed Permeation Emission Results 

Rig #11 - 2004 Ford Taurus 

Fuel 

4-week Avg. 

mg/hour 

Diurnal Test ID 

mg/day Ratio 

Specific 

Reactivity 

g O3/g VOC 

E0 3.59 6370 48.0 13.4 2.91 

E0b 2.53 6889 29.7 11.7 3.51 

Avg. = 3.06 38.9 12.6 3.21 

 

E6 11.2 6507 144.1 12.9 2.09 

 

E6Hi 4.02 6598 88.7 20.3 2.58 

E10 6.36 6675 149.3 24.1 2.23 

 6676 97.3 15.7 2.43 

Avg. = 123.3 19.9 2.33 

 

E20 5.42 6805 102.0 18.8 2.40 

 

Rig #12 - 2004 Chrysler Sebring 

Fuel 

4-week Avg. 

mg/hour 

Diurnal Test ID 

mg/day Ratio 

Specific 

Reactivity 

g O3/g VOC 

E0 3.22 6372 38.7 12.0 5.48 

 6383 31.0 9.64 4.10 

E0b 2.68 6874 38.3 14.3 3.73 

Avg. = 2.95 36.0 12.0 4.44 

 

E6 3.45 6492 49.6 14.4 3.30 

 

E6Hi 3.86 6569 45.0 11.7 3.14 

E10 4.65 6642 64.3 13.8 2.85 

 

E20 5.38 6778 74.7 13.9 2.92 
23

Table 7 (cont) 

Detailed Permeation Emission Results 

Rig #14 - 2005 Chevrolet Tahoe 

Fuel 

4-week Avg. 

mg/hour 

Diurnal Test ID 

mg/day Ratio 

Specific 

Reactivity 

g O3/g VOC 

E0 18.8 6360 250.5 13.3 3.80 

 6388 248.1 13.2 3.85 

E0b 18.4 6645 282.7 15.4 3.89 

E0c 20.5 6892 262.8 12.8 3.91 

Avg. = 19.2 261.0 13.7 3.9 

 

E10 29.8 6454 466.3 15.6 3.05 

 

E85 16.3 6555 142.3 8.68 2.63 

 6566 112.8 6.88 2.82 

Avg. = 127.6 7.78 2.73 

 

E20 27.6 6779 359.5 13.0 3.36 

Rig and Fuel Type Diurnal Result Comparisons

A table was made of the diurnal emission rates for the various rigs and fuels to look for trends or 

relationships. Table 8 below shows the diurnal results for all of the test fuels. Rig 1 showed a large 

increase in permeation when any of the ethanol-containing fuels was evaluated. Rig 2 was higher in basic 

permeation level, and showed proportionately less of an increase from the ethanol fuels. Rig 11 had very 

low permeation emissions but still increased when evaluated on the ethanol fuels. Rig 12, the “Zero Fuel 

Evaporative Emission” system, had a different result when tested on the ethanol-containing fuels in that 

the increase due to the ethanol was only 9 to 39 mg/day more than the base permeation rate, a much 

smaller increase than seen in the other rigs. 

Table 8 

Diurnal Emissions Test Results 

Total (Ethanol) – mg/day 

Test Fuel Difference from E0, mg/day 

 E0 E6 E6Hi E10 E20 E85 E6 E6Hi E10 E20 

Rig 1 91 (1) 475 (149) 361 (91) 468 (184) 508 (231) 384 270 377 417 

Rig 2 458 (5) 1426 (417) 1227 (391) 1301 (422) 1765 (623) 968 769 843 1307 

Rig 11 39 (2) 144 (20) 89 (19) 123 (34) 102 (38) 105 50 84 63 

Rig 12 36 (4) 50 (13) 45 (15) 64 (24) 75 (31) 14 9 28 39 

Rig 14 261 (9) - - 466 (139) 360 (111) 128 (76) 

Average* 177 (4) 524 (150) 430 (129) 484 (161) 562 (207) 347 253 307 385 

* Averages for E0, E10 and E20 are five-rig; those for E6 and E6Hi are four-rig. 
24

Steady-State Permeation Measurements

The plot format shown in Figures 21-25 was developed to compare the steady-state permeation rate 

results for each rig on the various fuels. The horizontal axis is a chronological sequence (not necessarily a 

linear time-scale) of the tests as they were accumulated. The red filled-box data points represent the 

ethanol permeation rate. The laboratory established that 1 mg/hour was the detection limit of the 

analytical procedure used to establish the ethanol content, and if the test level was less than 1.0 mg/hour it 

was reported as “below detection limit,” or BDL, and counted as zero in the calculation of the total. The 

black diamonds are the (non-ethanol) hydrocarbon, and the blue triangles are the total of the two, or the 

total permeation rate in mg/hour. A horizontal blue line is drawn at the average level of the last four data 

points. 

Rig 1 started the stabilization on fuel E0 with an initial fill on January 11, 2005 and was tested on the 

following day to measure the permeation rate. Permeation measurements were made each week, not 

necessarily on the same day of the week, although that was the normal case. The actual test dates are 

contained in the data record file known as “rigsum.xls,” and are available on the CRC web-site. 

A concern arose when ethanol was detected in the steady-state permeation results on the E0 fuel, even 

though there was no ethanol in the test fuel. The first three tests on the E0 fuel reported no ethanol, but the 

Ethanol Impact - Stabilized Permeation

Rig 1

0

10

20

30

40

50

60

Permeation - mg/hr

Total

4 Wk. Avg.

Non-Ethanol HC

Ethanol

E0 E6Hi E6 E10 E20 E0b

Figure 21 
25

fourth test (#6306 on February 2, 2005) reported 4.8 mg/hour as the ethanol component. A discussion 

arose concerning the source and authenticity of the measurement. The following week’s measurement 

was 2.3, and then 4.8, 1.2 and 1.2 mg/hour in succeeding weeks. The test on March 9 returned to BDL for 

ethanol. A similar pattern arose, at the same time period, on Rig 2, as will be discussed later. Ethanol 

was not detected in Rigs 11, 12 or 14 during the initial steady-state permeation E0 testing. A separate 

discussion concerning the “ethanol hang-up” is provided in the appendix at the end of this report. 

The steady-state permeation rate increased when the 5.7 Volume% ethanol fuel (E6) was introduced, as 

shown in Figure 21. The four-week final average permeation rate was 7.04 mg/hour on Fuel E0 and 

increased to 25.6 mg/hour on the 5.7 Volume% ethanol fuel. The steady-state permeation rate increased 

slightly on the higher aromatics E6Hi fuel, with an average of 29.2 mg/hour, and was higher yet (35.2 

mg/hour) on the 10 Volume% ethanol fuel. The E20 steady-state average value was 43.4 mg/hour. The 

average of the original and the final steady-state permeation rate measurements on the E0 fuel (7.04 and 

8.57) was 7.8 mg/hour 

Rig 2 also received its initial fill of the E0 test fuel on January 11, 2005, with its first test on the following 

day. (The practice was later changed to not test on the day following the fuel change, but test after a week 

or more exposure.) It showed ethanol in the permeate on the fourth week, on February 4, of 8.8 mg/hour, 

and 7.9 mg/hour the following week, during the same time period as was seen on Rig 1. A check was 

made for any sort of a laboratory or soak room contamination problem, without finding any source of 

contamination or error. An expanded discussion on the ethanol “hang-up” appears in the appendix to this 

report. 

Figure 22

Ethanol Impact - Stabilized Permeation

Rig 2

0

20

40

60

80

100

120

140

160

180

Permeation - mg/hr

Total

4 Wk. Avg.

Non-Ethanol HC

Ethanol

E0 E6Hi E6 E10 E20 E0b
26

The following observations were made regarding the second test band in Figure 22. The first test on the 

E6 fuel was made after nine days of exposure. The second week’s test after 17 days shows that the total 

permeation trend had approached the eventual stabilized level. The ethanol content, shown in the red solid 

squares as the lower of the three trends in the plot, appeared to be increasing slightly over the nine weeks 

of exposure. The permeation was declared to be stabilized after the 10th week of stabilization, and the rig 

was then submitted for the diurnal test. 

The permeation rate decreased slightly when the higher aromatics E6Hi fuel was introduced, and then 

increased with the introduction of the 10 Volume% ethanol fuel (E10). The 4-week average for the tests 

on the E10 fuel was 101.5 mg/hour, and 148.8 mg/hour on the E20 fuel. The average of the two steadystate averages on the E0 fuel (42.5 and 33.7) was 38.1 mg/hour 

The permeation rate for Rig 11 was very low, ~ 3 mg/hour on the E0 fuel, as shown in Figure 23, which 

created measurement challenges. The measurement period was increased from three to five hours during 

the E6 fuel measurement period as was discussed earlier in this section. 

The permeation performance of Rig 11 was erratic on the E6 fuel. The erratic performance continued for 

the first two tests on the E6Hi fuel, when the permeation suddenly dropped from 24 mg/hour to ~4 

mg/hour for no identified reason. This erratic condition may have also been present during the diurnal 

evaluation on the E6 fuel, but there is at present no basis to invalidate the data. 

Figure 23

Ethanol Impact - Stabilized Permeation

Rig 11

0

5

10

15

20

25

Permeation - mg/hr

Total

4 Wk. Avg.

Non-Ethanol HC

Ethanol

E0 E6Hi E6 E10 E20 E0b
27

Rig 12 was expected to have low permeation as it was produced and certified to be a “zero fuel 

evaporative emission” vehicle. As anticipated, the steady-state permeation results were very low (Note 

the vertical scale on Figure 24). The 4-week average permeation rate on the E0 fuel was 3.2 mg/hour for 

the original test sequence, with any ethanol content below the detectable limit and 2.7 mg/hour on the 

final series, with about a 0.5 g/hour ethanol fraction. The E6 fuel increased the permeation rate slightly, 

mainly because the ethanol component triggered into the detectable limit of 1 mg/hour. 

Unlike the other rigs, the high aromatics fuel, E6Hi, increased the permeation rate of Rig 12 over the 

value established for the lower aromatics E6 fuel. The 4-week average level was 3.4 mg/hour on the E6 

fuel, and 3.9 mg/hour on the E6Hi fuel. The data suggests that although the non-ethanol measurement 

stayed about the same, there was an increase in the mass rate of the ethanol in the permeate with the 

higher aromatics fuel compared to the E6 fuel. The E10 steady-state average was 4.6 mg/hour, and the 

E20 value was 5.4 mg/hour 

The final test sequence on the E0 fuel shows an ethanol content at the 0.5 mg/hour level, where the initial 

E0 tests were declared as below the detectable limit. This is attributed to the fact that the laboratory 

became more confident in declaring ethanol measurements below the level of 1 mg/hour as the program 

progressed. 

The permeation results with the E20 fuel were the highest measured of the four test fuels, but the 

magnitude of the increase, when compared to the base fuel (E0), was low, less than 3 mg/hour. 

Ethanol Impact - Stabilized Permeation

Rig 12

0

1

2

3

4

5

6

7

8

Permeation - mg/hr

Total

4 Wk. Avg.

Non-Ethanol HC

Ethanol

E0 E6Hi E6 E10 E20 E0b

Figure 24 
28

Rig 14 was tested on the E0, E10, E20 and E85 fuels. The committee authorized a final test on the E0 

fuel after the E85 evaluation to see if it would return to the previously measured E0 level. The results of 

the steady-state evaluation are shown in Figure 25. The ethanol in the permeate jumped to the 8 mg/hour 

level on the second test with the E10 fuel. The E10 steady-state permeation (29.8 mg/hr) was 1.6 times 

the E0 steady-state rate of 18.8 mg/hr, more like the results from Rigs 11 and 12, than Rigs 1 and 2. The 

4-week steady-state average on the E20 test fuel was 27.6 mg/hour, close, but slightly less, than the E10 

4-week average of 29.8 mg/hour.

Figure 25 

Ethanol Impact - Stabilized Permeation

Rig 14

0

5

10

15

20

25

30

35

Permeation - mg/hr

Total

4 Wk. Avg.

Non-Ethanol HC

Ethanol

E0 E85 E10 E0b E20 E0c
29

Steady-State Permeation Results by Rig 

The steady-state tests were used to determine fuel system stability following the introduction of a new 

fuel and to indicate that the rig was ready for the diurnal evaluation. A three or five hour steady-state test 

was performed in a SHED to determine the 105°F hourly permeation rate. The 4-week average steadystate permeation rates provide another measure of the permeation performance of the various fuels on the 

different fuel systems, and are presented below. 

Rig 1 - The bar chart in Figure 26 is used to 

illustrate the steady-state performance of the five 

test fuels on Rig 1. The hourly permeation rate is 

the lowest on the base fuel (E0) and increases to 

43 mg/hour on fuel E20. The higher aromatic 

E6Hi fuel had slightly higher permeation than the 

E6 fuel on the steady-state measurement, a 

different finding than was indicated on the diurnal 

test. 

Rig 2 – Figure 27 shows the steady-state 

permeation estimate on the E6Hi fuel to be lower 

than the E6 fuel, more in line with the diurnal test 

results, while the E10 permeation is slightly 

higher than the E6 result, and the E20 permeation 

is substantially higher. 

Stabilized Permeation Levels - Rig 1

7.8

25.6

29.2

35.2

43.4

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

45.0

50.0

E0 E6 E6Hi E10 E20

Test Fuel

Stabilized Permeation - mg/hr

Stabilized Permeation Levels - Rig 2

38.2

97.7

88.9

101.5

148.8

0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

160.0

E0 E6 E6Hi E10 E20

Test Fuel

Stabilized Permeation - mg/hr

Figure 26 

Figure 27 
30

Rig 11 steady-state test results, shown in Figure 

28, are distorted by the highly variable results 

experienced during the tests on the E6 fuel (see 

the earlier steady-state discussion on Rig 11). 

The E20 permeation was lower than the results 

measured with the E10 fuel, a different result 

than was seen on Rigs 1, 2 and 12. 

Rig 12 steady-state permeation results, shown in 

Figure 29 are more like the relationship seen with 

Rigs 1 and 2. 

Rig 14 steady-state results, shown in Figure 30, 

indicate lower emission on the E20 fuel than was 

measured on E10, similar to the behavior of Rig 11. 

The steady-state 105°F permeation result on the E85 

fuel was lower (-2.8 mg/hour) than the E0 base fuel, 

but not at half the value, as the diurnal results 

indicated. 

Stabilized Permeation Levels - Rig 12

3.0

3.4

3.9

4.6

5.4

0.0

1.0

2.0

3.0

4.0

5.0

6.0

E0 E6 E6Hi E10 E20

Test Fuel

Stabilized Permeation - mg/hr

Stabilized Permeation Levels - Rig 14

19.2

29.8

27.6

16.4

0

5

10

15

20

25

30

35

E0 E10 E20 E85

Test Fuel

Stabilized Permeation - mg/hr

Figure 30 

Figure 28 

Stabilized Permeation Levels - Rig 11

3.1

11.2

4.4

6.2

5.4

0.0

2.0

4.0

6.0

8.0

10.0

12.0

E0 E6 E6Hi E10 E20

Test Fuel

Stabilized Permeation - mg/hr

Figure 29 
31

In summary, the steady-state results may offer a slightly different picture of the permeation behavior of 

the different fuels on the different rigs, relative to the diurnal results. The small sample size, and the 

limited testing conducted, suggest some caution in evaluating these observed differences. 

Speciation and Reactivity

Diurnal Speciation Results – A sample of the ambient HC concentration in the VT-SHED was collected 

in a TedlarTM bag at the start and the end of the 24-hour diurnal period and later analyzed for HC species 

using a VarianTM chromatograph. The results of this “speciation” allowed the calculation of the average 

reactivity of the permeate for each of the rigs and fuels. 

An example of the speciation results and the reactivity calculations for Rig 1 – Fuel E0, Test 6389, is 

shown in Table 9. Table 9 is one file in a Microsoft EXCEL® workbook titled “SHED Speciation and 

Reactivity Calculations for the Final Report.xls,” available on the CRC web-site in the files for the E-65-3 

report. This workbook contains all of the SHED speciations for the test fuels evaluated in this program. 

Each file has been reordered into three vertical groups. The top group is those molecules with identified 

mass that have an assigned Carter Maximum Incremental Reactivity (MIR) value. The second vertical 

group is those measured mass components that do not have an assigned MIR value, and the last group is 

the molecules that had zero measured mass, but would have been identified if they were present, using the 

“Auto-Oil” chromatographic test technique. The first and second vertical groups were sorted in 

descending order of mass in each group. The lengthy listing of the third group, of those molecules with no 

detected mass, is offered to indicate to the reader what would have been measured, if present, using the 

chromatographic techniques available at the laboratory. 

This table, and the others in the workbook, are organized from left to right as follows. The first column is 

the elution order number, or the order that the molecules would appear at the end of the chromatographic 

column. The second column is the specific molecule’s name. The third column is the CAS number8 for 

the molecule. The fourth column is the MIR value for the molecule, or the specific grams of ozone 

formed for each gram of HC identified under certain conditions. The fifth column is the net mass of each 

species identified in the SHED sample by the chromatograph. The sixth column is the percentage of the 

total mass identified as this species. The final column is the prediction of the mass of ozone that would be 

produced by that mass of that molecule using the Carter methodology. 

 

8 The CAS number is the Chemical Abstract Service registry number assigned to each specific molecule. CAS 

registry numbers are copyrighted by the American Chemical Society. Redistribution rights for CAS registry numbers 

are reserved by the American Chemical Society. “CAS registry” is a registered trademark of the American Chemical 

Society. The CAS REGISTRY mostly covers substances identified from the scientific literature from 1957 to the 

present with some classes (fluorine- and silicon-containing compounds) going back to the early 1900s. Each 

substance in REGISTRY is identified by a unique numeric identifier called a CAS Registry Number.
32

Table 9 

Rig: 01E0 

Test#: 6389 

Detailed Hydrocarbon Speciation Results 24-Hour 

Elution No. Species Name CAS #

MIR

g O3/g HC

Net mass 

(mg) 

% total 

mass 

Predicted 

Ozone mg 

81 Toluene 00108-88-3 3.97 14.321 17% 56.85 

18 2-Methylbutane (Isopentane) 00078-78-4 1.67 10.787 13% 18.01 

111.1 m-Xylene 00108-38-3 10.61 8.835 10% 93.74 

21 n-Pentane 00109-66-0 1.53 3.666 4% 5.61 

117 ortho-Xylene 00095-47-6 7.48 2.951 3% 22.08 

111.2 p-Xylene 00106-42-3 4.24 2.591 3% 10.99 

36.1 2-MePentane 00107-83-5 1.78 2.289 3% 4.08 

135.1 1,2,4-TriMeBenz 00095-63-6 7.18 2.131 2% 15.30 

109 Ethylbenzene 00100-41-4 2.79 2.066 2% 5.77 

53 Benzene 00071-43-2 0.81 1.952 2% 1.58 

34 2,3-Dimethylbutane 00079-29-8 1.13 1.514 2% 1.71 

128 1-Methyl-3-Ethylbenzene 00620-14-4 9.37 1.501 2% 14.06 

40 n-Hexane 00110-54-3 1.43 1.475 2% 2.11 

63 2,2,4-TriMePentane (IsoOctane) 00540-84-1 1.43 1.437 2% 2.05 

26 2-Methyl-2-butene 00513-35-9 14.44 1.298 2% 18.75 

 Ethanol 00064-17-5 1.69 1.260 1% 2.13 

49 Methylcyclopentane 00096-37-7 2.40 1.244 1% 2.99 

56 Cyclohexane 00110-82-7 1.44 1.130 1% 1.63 

79 2,3,4-Trimethylpentane 00565-75-3 1.22 0.986 1% 1.20 

74 Methylcyclohexane 00108-87-2 1.97 0.955 1% 1.88 

130 1,3,5-Trimethylbenzene 00108-67-8 11.22 0.953 1% 10.69 

23 t-2-Pentene 00646-04-8 10.23 0.910 1% 9.31 

38 3-Methylpentane 00096-14-0 2.06 0.905 1% 1.87 

9 2-Methylpropane 00075-28-5 1.34 0.892 1% 1.20 

12 n-Butane 00106-97-8 1.32 0.874 1% 1.15 

86 3-Methylheptane 00589-81-1 1.33 0.832 1% 1.11 

57 2-Methylhexane 00591-76-4 1.36 0.809 1% 1.10 

42 t-2-Hexene 04050-45-7 8.35 0.754 1% 6.30 

59.2 3-Methylhexane 00589-34-4 1.84 0.722 1% 1.33 

129 1-Methyl-4-Ethylbenzene 00622-96-8 3.75 0.705 1% 2.64 

127 n-Propylbenzene 00103-65-1 2.20 0.661 1% 1.45 

136 n-Decane 00124-18-5 0.81 0.608 1% 0.49 

90 2,2,5-Trimethylhexane 03522-94-9 1.31 0.541 1% 0.71 

96 n-Octane 00111-65-9 1.09 0.532 1% 0.58 

45.1 c-2-Hexene 07688-21-3 8.35 0.520 1% 4.34 

83 2-Methylheptane 00592-27-8 1.18 0.500 1% 0.59 

66 n-Heptane 00142-82-5 1.26 0.495 1% 0.62 

77 2,4-Dimethylhexane 00589-43-5 1.79 0.476 1% 0.85 

29 2,2-Dimethylbutane 00075-83-2 1.33 0.465 1% 0.62 

50 2,4-Dimethylpentane 00108-08-7 1.63 0.447 1% 0.73 

58 2,3-Dimethylpentane 00565-59-3 1.53 0.376 0% 0.58 
33

Table 9 (continued)

Detailed Hydrocarbon Speciation Results 24-Hour 

Elution No. Species Name CAS #

MIR

g O3/g HC

Net mass 

(mg) 

% total 

mass 

Predicted 

Ozone mg 

133 1-Ethyl-2-Methylbenzene 00611-14-3 6.61 0.365 0% 2.41 

25 c-2-Pentene 00627-20-3 10.23 0.361 0% 3.69 

115 Styrene 00100-42-5 1.94 0.346 0% 0.67 

14 t-2-Butene 00624-64-6 13.90 0.331 0% 4.60 

84.2 4-MeHeptane 00589-53-7 1.46 0.321 0% 0.47 

113 3-Methyloctane 02216-33-3 1.42 0.257 0% 0.36 

140 1,2,3-Trimethylbenzene 00526-73-8 11.25 0.239 0% 2.69 

39.1 2-Methyl-1-pentene 00763-29-1 5.15 0.235 0% 1.21 

48 2,2-Dimethylpentane 00590-35-2 1.21 0.199 0% 0.24 

16 c-2-Butene 00590-18-1 13.22 0.184 0% 2.44 

20 2-Methyl-1-butene 00563-46-2 6.47 0.179 0% 1.16 

1 Methane 00074-82-8 0.01 0.124 0% 0.00 

76.1 2,5-DiMeHexane 00592-13-2 1.66 0.121 0% 0.20 

30 Cyclopentene 00142-29-0 7.32 0.099 0% 0.72 

19.1 1-Pentene 00109-67-1 7.73 0.096 0% 0.74 

76.2 EtCyPentane 01640-89-7 2.25 0.062 0% 0.14 

39.2 1-Hexene 00592-41-6 6.12 0.033 0% 0.20 

Mass w/MIR 

Values 81.9 95.7% 352.7 

Specific Reactivity 4.31 

43 3-Methyl-t-2-pentene 00616-12-6 1.196 1% 

47 Unknown #16 0.686 1% 

61 3-Methyl-c-2-pentene 00922-62-3 0.534 1% 

82.2 c-1,3-Dimethylcyclopentane 02532-58-3 0.330 0% 

88 2-Me-3-Et-pentane 00609-26-7 0.316 0% 

36.2 c-1,3-Dimethylcyclohexane 00638-04-0 0.288 0% 

62 4-Me-c-2-Pentene 00691-38-3 0.140 0% 

45.2 t-1,2-Dimethylcyclopentane 00822-50-4 0.130 0% 

123 3-MeCyclopentene 01120-62-3 0.069 0% 

Mass w/o 

MIR Values 3.69 4.3% 

4 Ethane 00074-84-0 0.000 0% 

2 Ethylene 00074-85-1 0.000 0% 

3 Acetylene (Ethyne) 00074-86-2 0.000 0% 
34

Table 9 (continued)

Detailed Hydrocarbon Speciation Results 24-Hour 

Elution No. Species Name CAS #

MIR

g O3/g HC

Net mass 

(mg) 

% total 

mass 

Predicted 

Ozone mg 

6 Propane 00074-98-6 0.000 0% 

8 Propyne 00074-99-7 0.000 0% 

22 2-Methyl-1,3-butadiene 00078-79-5 0.000 0% 

168 Naphthalene 00091-20-3 0.000 0% 

135.2 1,2,4,5-Tetramethylbenzene 00095-93-2 0.000 0% 

122 t-Butylbenzene 00098-06-6 0.000 0% 

162 Isopropylbenzene (Cumene) 00098-82-8 0.000 0% 

141 1,3-Diisopropylbenzene 00099-62-7 0.000 0% 

166 4-Isopropyltoluene (p-Cymene) 00099-87-6 0.000 0% 

70.1 1,4-Diisopropylbenzene 00100-18-5 0.000 0% 

147 n-Butylbenzene 00104-51-8 0.000 0% 

145 1,4-Diethylbenzene 00105-05-5 0.000 0% 

10.2 1-Butene 00106-98-9 0.000 0% 

11 1,3-Butadiene 00106-99-0 0.000 0% 

15 1-Butyne 00107-00-6 0.000 0% 

125.2 244Trimethyl1pentene 00107-39-1 0.000 0% 

75 2,4,4-Trimethyl-2-Pentene 00107-40-4 0.000 0% 

59.1 Cyclohexene 00110-83-8 0.000 0% 

91 1-Octene 00111-66-0 0.000 0% 

120 n-Nonane 00111-84-2 0.000 0% 

172 n-Dodecane 00112-40-3 0.000 0% 

169 1-Dodecene 00112-41-4 0.000 0% 

5 Propene 00115-07-1 0.000 0% 

10.1 2-Methylpropene 00115-11-7 0.000 0% 

118 1-Nonene 00124-11-8 0.000 0% 

146 1,2-Diethylbenzene 00135-01-3 0.000 0% 

138 sec-Butylbenzene 00135-98-8 0.000 0% 

143 1,3-Diethylbenzene 00141-93-5 0.000 0% 

32 Cyclopentane 00287-92-3 0.000 0% 

7 AlBenz 00300-57-2 0.000 0% 

163.1 Allene (Propadiene) 00463-49-0 0.000 0% 

13 2,2-Dimethylpropane 00463-82-1 0.000 0% 

51 2,2,3-Trimethylbutane 00464-06-2 0.000 0% 

163.2 1,2,3,4-TetMeBenzene 00488-23-3 0.000 0% 

142 Indan 00496-11-7 0.000 0% 

19.2 2-Butyne 00503-17-3 0.000 0% 

158 1,2,3,5-Tetramethylbenzene 00527-53-7 0.000 0% 

137 Amylbenz 00538-68-1 0.000 0% 

80 Isobutylbenzene 00538-93-2 0.000 0% 

28 Cyclopentadiene 00542-92-7 0.000 0% 

24 3,3-Dimethyl-1-butene 00558-37-2 0.000 0% 

78 2,3,3-Trimethylpentane 00560-21-4 0.000 0% 
35

Table 9 (continued)

Detailed Hydrocarbon Speciation Results 24-Hour 

Elution No. Species Name CAS # 

MIR

g O3/g HC 

Net mass 

(mg) 

% total 

mass 

Predicted 

Ozone mg 

54 3,3-Dimethylpentane 00562-49-2 0.000 0% 

92 3,3-Dimethylhexane 00563-16-6 0.000 0% 

17 3-Methyl-1-butene 00563-45-1 0.000 0% 

82.1 2,3-dimethylhexane 00584-94-1 0.000 0% 

98.2 1,1-Dimethylcyclohexane 00590-66-9 0.000 0% 

73 2,2-DiMeHexane 00590-73-8 0.000 0% 

84.1 1-MeCyHexene 00591-49-1 0.000 0% 

64 1-Heptene 00592-76-7 0.000 0% 

37 c-1,4-DiMeCyHexane 00624-29-3 0.000 0% 

44 2-Methyl-2-pentene 00625-27-4 0.000 0% 

46 ETBE 00637-92-3 0.000 0% 

69 4-Methyl-t-2-pentene 00674-76-0 0.000 0% 

31.1 4-methyl-1-pentene 00691-37-2 0.000 0% 

52 1-Methylcyclopentene 00693-89-0 0.000 0% 

31.2 3-methyl-1-pentene 00760-20-3 0.000 0% 

150 3-Ethyl-c-2-Pentene 00816-79-5 0.000 0% 

153 1-Undecene 00821-95-4 0.000 0% 

151 1,3-Dimethyl-4-Ethylbenzene 00874-41-9 0.000 0% 

105 3,5-Dimethylheptane 00926-82-9 0.000 0% 

148 1,2-Dimethyl-4-Ethylbenzene 00934-80-5 0.000 0% 

100 2,3,5-Trimethylhexane 01069-53-0 0.000 0% 

144 1-Methyl-2-Propylbenzene 01074-17-5 0.000 0% 

149 1-Methyl-3-Propylbenzene 01074-43-7 0.000 0% 

154 n-Undecane 01120-21-4 0.000 0% 

33 MTBE 01634-04-4 0.000 0% 

104 Ethylcyclohexane 01678-91-7 0.000 0% 

125.3 PrCyHexane 01678-92-8 0.000 0% 

119 1,4-Dimethyl-2-Ethylbenzene 01758-88-9 0.000 0% 

103 c- & t-4-Nonene 02198-23-4 0.000 0% 

98.1 c-1,2-Dimethylcyclohexane 02207-01-4 0.000 0% 

89 t-1,3 02207-03-6 0.000 0% 

67.1 t-1,4-Dimethylcyclohexane 02207-04-7 0.000 0% 

101 2,4-Dimethylheptane 02213-23-2 0.000 0% 

112 4-Methyloctane 02216-34-4 0.000 0% 

152 2-Methyl-2-Hexene 02738-19-4 0.000 0% 

110.1 1,3-Dimethyl-2-Ethylbenzene 02870-04-4 0.000 0% 

55 2,3-DiMeHeptane 03074-71-3 0.000 0% 

110.2 2-MeOctane 03221-61-2 0.000 0% 

68.1 3-Me-1-Hexene 03404-61-3 0.000 0% 

139 3-Me-t-3-Hexene 03899-36-3 0.000 0% 

125.1 2,4-DiMeOctane 04032-94-4 0.000 0% 

121 1-Methyl-4-Isobutylbenzene 05161-04-6 0.000 0% 
36

Table 9 (continued)

Detailed Hydrocarbon Speciation Results 24-Hour 

Elution No. Species Name CAS #

MIR

g O3/g HC

Net mass 

(mg) 

% total 

mass 

Predicted 

Ozone mg 

71 t-2-Nonene 06434-78-2 0.000 0% 

97.2 c-2-Heptene 06443-92-1 0.000 0% 

99 t-1,2-DiMeCyHexane 06876-23-9 0.000 0% 

70.2 c-2-Octene 07642-04-8 0.000 0% 

41.2 c-3-Hexene 07642-09-3 0.000 0% 

67.2 c-3-Heptene 07642-10-6 0.000 0% 

97.1 23-diMe-2-pentene 10574-37-5 0.000 0% 

41.1 t-3-Hexene 13269-52-8 0.000 0% 

27 t-2-Octene 13389-42-9 0.000 0% 

68.2 t-2-Heptene 14686-13-6 0.000 0% 

65 t-3-Heptene 14686-14-7 0.000 0% 

94 t-4-Octene 14850-23-8 0.000 0% 

87 2,2-Dimethyloctane 15869-87-1 0.000 0% 

161 1c-2t-3-TriMeCyPentane 15890-40-1 0.000 0% 

157 Methylindan 27133-93-3 0.000 0% 

35 Unknown #1 0.000 0% 

60 Unknown #2 0.000 0% 

72 Unknown #3 0.000 0% 

85 Unknown #4 0.000 0% 

95 Unknown #5 0.000 0% 

102 Unknown #7 0.000 0% 

106 Unknown #8 0.000 0% 

107 Unknown #9 0.000 0% 

108 Unknown #10 0.000 0% 

114 Unknown #11 0.000 0% 

116 Unknown #12 0.000 0% 

124 Unknown #13 0.000 0% 

126 Unknown #14 0.000 0% 

131 Unknown #15 0.000 0% 

132 Unknown #17 0.000 0% 

134 3-Methylnonane 0.000 0% 

155 Unknown #18 0.000 0% 

156 Unknown #19 0.000 0% 

159 Unknown #20 0.000 0% 

160 Unknown #21 0.000 0% 

165 Unknown #23 0.000 0% 

167 Unknown #24 0.000 0% 

170 Unknown #25 0.000 0% 

Total 85.6 100.0

% 

83.9 SHED FID (mg) 

102.0 % GC of SHED FID 
37

Specific Reactivity Calculations - The Carter Maximum Incremental Reactivity (MIR) scale for the 

various VOC molecules was adopted by the CARB. It estimates that for each gram of the various VOC 

molecules, X grams of ozone would be produced under ideal conditions for ozone formation. The 

reference (approved by the CARB Staff for this purpose) to the values and the documentation is “THE 

SAPRC-99 CHEMICAL MECHANISM AND UPDATED VOC REACTIVITY SCALES” which can be 

found at 

http://helium.ucr.edu/~carter/reactdat.htm

The link to the actual data is found down two thirds of the page, under the heading VOC Reactivity Data 

(Excel format) as of February 5, 2003 (r02tab.xls). It contains CAS number, MIR value and species name 

for 543 different species. 

The average specific reactivity of the permeate was calculated for each of the 25 diurnal tests conducted 

on the five rigs and five fuels. 

VOC reactivity varies with atmospheric conditions, in particular the VOC/NOx ratio. The MIR scale is 

based on low VOC/NOx ratios. The reactivity measure reported in this study, average VOC specific 

reactivity, has units of potential grams of ozone per gram of VOC and is a function of the composition of 

the VOC permeate. Specific reactivity provides an estimate of the ozone-forming potential per unit mass 

of the VOC permeate under conditions favorable for ozone formation, but it is not meant to predict actual 

levels of ozone and should be interpreted on a relative basis. Further, there are uncertainties in these 

reactivity estimates, e.g., the MIR scale represents a limited range of atmospheric conditions, does not 

include carryover of emissions from one day to the next, and does not include three-dimensional spatial 

variation in emissions. 

The mass emissions times the MIR gives the theoretical potential ozone that would be formed by that 

mass under ideal conditions. This calculation was performed on all the identified molecules that had MIR 

factors. Not all the molecules measured had MIR factors. The unidentified compounds were assumed to 

have the same reactivity as the average of the identified compounds with MIR factors. The mass of the 

compounds for which no MIR factors existed was determined to be insignificant. 

The specific reactivity for a speciated SHED diurnal sample was calculated by summing the mass of the 

individual species, and the predicted potential ozone using the MIR factor. The specific reactivity is the 

mass of ozone predicted divided by the mass of the hydrocarbons measured, in our example, 352.7 

mg/81.9 mg, or 4.31 g of potential O3/g VOC permeate emissions. 

The next part of this report discusses the specific reactivities calculated for the six fuels tested in this 

project. When the permeate specific reactivities of the five rigs were compared across test fuels, it was 

observed that Rig 11 consistently produced the lowest result. 
38

Thirteen diurnal tests on the E0 fuel were speciated (Table10). The average specific reactivity of the 

permeate of all the E0 diurnals was 3.99 (grams of ozone per gram of HC mixture), with two “eyeball” 

outliers, (test 6370 – Rig 11 = 2.91), and (test 6372 – Rig 12 = 5.48). The other six tests ranged from 3.80 

to 4.26. The third and fourth columns in Table 9 allow a comparison of the SHED calculation of mass and 

the gas chromatograph’s value. In general, reasonable agreement was found between the two estimates. 

The fifth and sixth columns report the identified mass (in mg and % of total) that had MIR factors for the 

individual species. Usually 90% or more had MIR values 

Table 10 

Fuel E0 Diurnal Permeate Reactivity Results 

Total GC 

Mass w/MIR 

Values 

Rig (test #) 

Test 

ID 

Reported 

SHED mg Mass - mg mg % 

Specific 

Reactivity 

Rig Wtd. 

Average 

1 6389 83.9 85.6 81.9 95.7% 4.31 

1b 6900 97.2 101.6 96.1 94.7% 4.15 

2 6390 463.3 391.4 369.8 94.5% 4.26 

2b 6913 451.6 435.6 412.6 94.7% 4.16 

11 6370 48.0 36.6 32.5 88.8% 2.91 

11b 6889 29.7 32.4 30.9 95.4% 3.51 

12(1) 6372 38.7 29.3 26.0 88.8% 5.48 3.99 

12(2) 6383 31.0 34.1 33.4 97.9% 4.10 

12b 6874 38.3 41.0 39.8 97.3% 3.73 

14(1) 6360 250.5 250.4 239.2 95.5% 3.80 

14(2) 6388 248.1 241.3 236.9 98.2% 3.85 

14b 6645 282.7 274.7 259.7 94.6% 3.89 

14c 6892 262.8 265.8 247.9 93.3% 3.91 
39

The average specific reactivity of the permeates for the five diurnal tests on the E6 fuel was 3.00 (Table 

11), but this included one relatively low result (test 6507 – Rig 11 = 2.09). The average specific reactivity 

with that test omitted was 3.24. The 3.24 number compares well with the Fuel B permeate average of 

3.27 from the original E-65 test program. 

Table 11 

Fuel E6 Diurnal Permeate Reactivity Results 

Total GC 

Mass w/MIR 

Values 

Rig (test #) 

Test 

ID 

Reported 

SHED mg Mass - mg mg % 

Specific 

Reactivity 

Rig Wtd. 

Average 

1(1) 6471 417.1 264.1 264.1 100.0% 3.05 

1(2) 6479 533.3 461.3 447.3 97.0% 3.08 

2 6481 1426.0 1357.6 1326.8 97.7% 3.54 3.00 

11 6507 144.1 127.7 127.7 100.0% 2.09 

12 6492 49.6 36.8 36.0 97.8% 3.30 

Four tests on the E6Hi fuel were speciated, with an average permeate specific reactivity of 3.17 (Table 

12). Rig 11 had the lowest reactivity value for the four tests. 

Table 12 

Fuel E6Hi Diurnal Permeate Reactivity Results 

Total GC 

Mass w/MIR 

Values 

Rig (test #) 

Test 

ID 

Reported 

SHED mg Mass - mg mg % 

Specific 

Reactivity 

Rig Wtd. 

Average 

1 6571 360.9 270.9 270.9 100.0% 3.30 

2 6570 1227.0 1400.7 1290.1 92.1% 3.66 3.17 

11 6598 88.7 82.0 82.0 100.0% 2.58 

12 6569 45.0 39.2 38.7 98.6% 3.14 
40

The six diurnal tests on the E10 fuel had an average permeate specific reactivity of 2.94 (Table 13), with 

Rig 11 again yielding the lowest values. There is no current explanation why the fuel system components 

used in Rig 11 might produce a lower, or less reactive permeate. 

Table 13 

Fuel E10 Diurnal Permeate Reactivity Results

Total 

GC Mass w/MIR Values 

Rig (test #) 

Test 

ID 

Reported 

SHED mg 

Mass - 

mg mg % 

Specific 

Reactivity 

Rig Wtd. 

Average 

1 6665 467.8 443.2 438.2 98.9% 3.03 

2 6673 1300.6 1289.2 1262.3 97.9% 3.45 

11(1) 6675 149.3 163.2 160.8 98.6% 2.23 2.94 

11(2) 6676 97.3 118.5 116.3 98.2% 2.43 

12 6642 64.3 54.9 53.8 98.0% 2.85 

14 6454 466.3 436.6 426.4 97.7% 3.05 

The five diurnal tests on the E20 fuel had an average specific reactivity of 3.04 (Table 14), with a range of 

values from 2.40 to 3.36. Again, the lowest specific reactivity of the rigs evaluated was Rig 11. 

Table 14 

Fuel E20 Diurnal Permeate Reactivity Results

Total GC Mass w/MIR Values 

Rig (test #) 

Test 

ID 

Reported 

SHED mg Mass - mg mg % 

Specific 

Reactivity 

Rig Wtd. 

Average 

1 6806 508.1 568.4 558.3 98.2% 3.20 

2 6816 1765.1 1687.5 1650.8 97.8% 3.32 

11 6805 102.0 94.5 93.1 98.6% 2.40 

12 6678 74.7 63.6 63.5 100.0% 2.92 3.04 

14 6779 359.5 399.0 388.7 97.4% 3.36 
41

Two speciated diurnals were conducted on Rig 14 with the E85 fuel, and the results are shown in Table 

15. The two permeate specific reactivities measured were 2.63 and 2.82 with an arithmetic average value 

of 2.73. The specific reactivity of the E85 permeate is expected to be low compared to other fuels since 

the ethanol fraction of the diurnal permeate was approximately two-thirds of the total mass (59 to 65 mass 

%). 

Table 15 

Fuel E85 Diurnal Permeate Reactivity Results

Total GC 

Mass w/MIR 

Values 

Rig (test #) ID 

Reported 

SHED mg Mass -mg mg % 

Specific 

Reactivity 

Rig Wtd. 

Average 

14(1) 6555 142.3 137.6 137.4 99.9% 2.63 

14(2) 6566 112.8 105.6 102.5 97.0% 2.82 2.73 

Statistical Analysis

Statistical analyses were performed on the diurnal and steady-state emissions results, as well as on the 

specific reactivity results. Analysis of the residuals from preliminary regressions indicated that the 

variability in the diurnal data tended to be proportional to the magnitude of the measurement; therefore, a 

natural log transformation was used on the diurnal data, which yielded a constant standard deviation over 

the range of the data. However, the steady-state and reactivity data exhibited constant standard deviations 

without the log transformation, so no transformation was used for those variables. 

For each of the three dependent variables evaluated, tests were performed to determine the significance of 

three possible independent variables: 1) test timing; 2) fuel aromatics level; and 3) fuel ethanol content. 

Because E85 was only tested in one of the five vehicles (rigs), data for that fuel were not included in any 

of the analyses. All five vehicles (rigs) were included in the analyses for test timing and fuel ethanol 

content, but Rig 14 was not included in the analysis of the effect of fuel aromatics content because it was 

not tested on fuels E6 and E6Hi. 

In recent years, CRC has employed mixed models that include both fixed and random effects in the 

analysis of emissions data. In these analyses, the random effects are the vehicle intercepts and vehicle-byfixed effect interactions. The advantage of these mixed models is that the random effects are treated as 

being samples drawn from a normal population, and the resulting statistical tests include the observed 

variation in the random sample of vehicles. As a result, the tests of significance are applicable to the 

population of vehicles from which the sample was drawn. On the other hand, statistical tests using fixedeffect models are applicable only to the specific vehicles tested. 

While mixed models permit more powerful conclusions to be drawn, they also depend on having a large 

enough random vehicle sample to be able to draw conclusions on fuel effects in the face of vehicle-tovehicle variation. In this study, the small sample size (five vehicles) was not judged to be large enough to 

permit the use of mixed models, so fixed effects models were used. As a result, the statistical significance 

determinations made in this report apply only to the specific vehicles tested. 
42

Test Timing 

The E0 fuel was evaluated first and last on all the rigs. In addition, Rig 14 tested E0 after E85 and before 

E20. Examination of these tests on E0 allows determination of whether there was any change in rig 

performance over the course of the testing. These E0 results are shown graphically in Figure 31. The 

multiple initial E0 tests on Rigs 12 and 14 are the result of repeat diurnal tests and were thus very close 

together in time. The multiple final E0 results for Rig 14 are due to the testing of E0 before and after E20 

and are thus further apart in time, but not as far apart as they are from the initial E0 tests. 

a. Diurnal

0

50

100

150

200

250

300

350

400

450

500

1 2 11 12 14 Overall

Rig

Diurnal Measurement

Initial Test 1

Initial Test 2

Final Test 1

Final Test 2

 
43

b. Steady State

0

5

10

15

20

25

30

35

40

45

1 2 11 12 14 Overall

Rig

Steady State Measurement

Initial Test 1

Initial Test 2

Final Test 1

Final Test 2

c. Specific Reactivity

0

1

2

3

4

5

6

1 2 11 12 14 Overall

Rig

Specific Reactivity

Initial Test 1

Initial Test 2

Final Test 1

Final Test 2

Figure 31

An ANOVA that treated the individual fuels without regard to fuel characteristics was run for each of the 

dependent variables. The model included fixed effects for fuel, rig and fuel by rig interaction. Within the 
44

ANOVA, a contrast was set up to test the hypothesis that there were no significant differences between 

the E0 results at the beginning of the testing and the E0 results at the end of the testing (the extra E0 test 

on Rig 14 was treated as if it were made at the end of the test). No significant effect of test timing was 

observed for any of the three dependent variables (p ≥ 0.32). Given that no significant effect was 

observed, all E0 measurements were treated the same, regardless of when they were obtained, in 

subsequent analyses. 

Aromatics

Fuels E6 and E6Hi differed from one another primarily in their aromatics level. Comparison of these two 

fuels can thus determine the significance of any effect of aromatics content that was observed. These 

results are shown graphically in Figure 32. 

a. Diurnal

0

200

400

600

800

1000

1200

1400

1600

1 2 11 12 Overall

Rig

Diurnal Measurement

E6 Test 1

E6 Test 2

E6Hi Test 1

E6Hi Test 2
45

b. Steady State

0

20

40

60

80

100

120

1 2 11 12 Overall

Rig

Steady State Measurement

E6 Test 1

E6 Test 2

E6Hi Test 1

E6Hi Test 2

c. Specific Reactivity

0

0.5

1

1.5

2

2.5

3

3.5

4

1 2 11 12 Overall

Rig

Specific Reactivity

E6 Test 1

E6 Test 2

E6Hi Test 1

E6Hi Test 2

Figure 32 

An ANOVA that treated the individual fuels without regard to fuel characteristics was run for each of the 

dependent variables. The model included fixed effects for fuel, rig and fuel by rig interaction. Within the 
46

ANOVA, a contrast was set up to test the hypothesis that there were no significant differences between 

the E6 results and the E6Hi results. No significant effect of aromatics level was observed for any of the 

three dependent variables (p ≥ 0.11). Given that no significant effect was observed, aromatics level was 

not considered in subsequent analyses. 

Ethanol Content

In contrast to the other evaluations, the design of this experiment allows the evaluation of ethanol content 

as a continuous variable. Figure 33 shows the results for the three dependent variables vs. ethanol content 

for each rig. 

a. Diurnal Emissions vs. Ethanol Content

0

200

400

600

800

1000

1200

1400

1600

1800

2000

0 5 10 15 20 25

Ethanol Content, vol%

Diurnal Emissions - mg/day

Rig 1

Rig 2

Rig 11

Rig 12

Rig 14
47

b. Steady-State Emissions vs. Ethanol Content

0

20

40

60

80

100

120

140

160

0 5 10 15 20 25

Ethanol Content, vol%

Steady-State Emissions - mg/hr

Rig 1

Rig 2

Rig 11

Rig 12

Rig 14

c. Specific Reactivity vs. Ethanol Content

0

1

2

3

4

5

6

0 5 10 15 20 25

Ethanol Content, vol%

Specific Reactivity - g Ozone/g VOC

Rig 1

Rig 2

Rig 11

Rig 12

Rig 14

Figure 33
48

The plots indicate a general nonlinear relationship between the dependent variables and ethanol content. Closer 

inspection of the data reveals that, while the overall relationship is nonlinear, the data at nonzero ethanol contents 

is actually fairly linear: the nonlinearity exists between the E0 and ethanol-containing fuels. An example of this 

is shown in Figure 34 for Rig 1 diurnal emission results. 

Diurnal Emissions vs. Ethanol Content

0

100

200

300

400

500

600

0 5 10 15 20 25

Ethanol Content, vol%

Diurnal Emissions - g/hr

Figure 34

The dashed line is a linear fit vs. ethanol content for the five observations at nonzero ethanol contents. The 

reasonably good fit for these points contrasts with the E0 data. As a result of patterns like this in the data, a 

model was fit to the data that provides for a discontinuous function that includes a single point (intercept) based 

on the E0 data and a linear fit based on the fuels with nonzero ethanol content. This allows two tests to be 

performed to determine the effect of ethanol: one test that evaluates the effect of the presence or absence of 

ethanol, and another that evaluates the effect of changes in ethanol content for ethanol-containing fuels. 

The regression model is thus: 

y = a * Rig + b * Pr esent + c * Ethanol + Rig * Pr esent + Rig * Ethanol + ε

Where: 

Rig = Test rig identifier 

Present = Presence or absence of ethanol 

Ethanol = Ethanol content, vol% 

ε = Error term 

The presence or absence of ethanol was statistically significant (p ≤ 0.05) for all three independent variables. 

Both ln(diurnal) and steady-state emissions increased when ethanol was present, while Specific Reactivity 

decreased. Varying the ethanol content was significant for the steady-state data (emissions increased as ethanol 

content increased), but was not significant (p ≥ 0.44) for the ln(diurnal) and reactivity data. 
49

D. The CRC E-65-3 Steering Committee Members 

Richard Baker........................ Ford Motor Company 

Brent Bailey .......................... Coordinating Research Council 

Loren Beard........................... DaimlerChrysler 

Jane Beck .............................. Coordinating Research Council 

Norm Brinkman .................... General Motors Corporation 

Steve Cadle ........................... General Motors Corporation 

Dominic DiCicco .................. Ford Motor Company 

King Eng ............................... Shell Global Solutions (US), Inc. 

Frank Gerry ........................... BP 

Albie Hochhauser.................. Exxon Mobil Corporation 

Mike Ingham (Co-Chair) ...... Chevron Products Company 

Jeff Jetter ............................... Honda R&D Americas, Inc. 

Stuart Johnson ....................... Volkswagen of America, Inc. 

David Lax.............................. API 

Mani Natarajan...................... Marathon Petroleum Company LLC 

Robert Reynolds.................... Downstream Alternatives, Inc. 

 (Representing the Renewable Fuels Association) 

Chris Tennant........................ Coordinating Research Council 

Jim Uihlein............................ BP 

Marie Valentine (Co-Chair).. Toyota Technical Center 

Cynthia Williams .................. Ford Motor Company 

Ken Wright............................ ConocoPhillips 

The authors want to thank the members of the CRC Staff and the Emissions Committee who sponsored 

and guided this project. In particular, we want to thank Jim Uihlein of BP for performing the statistical 

analyses of the project data. We also want to thank Chevron for providing the test fuels used throughout 

the E-65 permeation studies and GM for donating the FFV used in this study. Special thanks go also to 

Stuart Seale, the data and quality manager at ATL, and Melanie Swords, staff member at HH&A, for their 

contributions to the project and the report. 
50

E. Appendix 

The Ethanol Hang-up

During our initial stabilization with the E0 fuel, Rigs 1 and 2 unexpectedly exhibited ethanol content in 

the permeate, which created considerable concern and discussion. It was surprising when Rigs 1 and 2 

indicated an ethanol component in the permeate long after the use of any ethanol-containing fuel. This 

led to the hypothesis that ethanol can lie dormant in the vehicle’s fuel system, or be stored and reappear at 

a much later time. 

Table 16 - 2001 Toyota Tacoma Stabilization – Fuel E0

Rig Fuel Week Date Test#

NonEtOH 

mg/hour 

EtOH 

mg/hour 

NonEtOH 

+ EtOH 

mg/hour 

Running 

Average 

mg/hour 

01 E0 01/11/05 Drain and 100% fill Fuel E0 

 0 01/12/05 6286 12.3 BDL 12.3 

 1 01/19/05 6293 13.8 BDL 13.8 

 2 01/26/05 6301 14.0 BDL 14.0 

 3 02/02/05 6306 11.5 4.8 16.3 14.1 

 4 02/09/05 6313 12.3 2.3 14.6 14.7 

 5 02/16/05 6324 10.8 4.8 15.6 15.1 

 02/18/05 Drain and 100% fill Fuel E0 

 NonEtOH Running

Ethanol Impact - Stabilized Permeation

Rig 1 - E0 Fuel

0

2

4

6

8

10

12

14

16

18

Permeation - mg/hr

Total

Non-Ethanol HC

Ethanol

The first three tests on Rig 1 detected 

no ethanol in the permeate, but the 

fourth test on 2-02-05, resulted in an 

ethanol rate estimate of 4.8 mg/hour. 

Rig 2 had a similar result during the 

same time period, as indicated later. 

The tests after 3-9-05 did not indicate 

ethanol in the permeate sample. 

Figure 35 
51

Rig Fuel Week Date Test#

NonEtOH 

mg/hour 

EtOH 

Mg/hour 

+ EtOH 

mg/hour 

Average 

mg/hour 

 6 02/23/05 6331 10.4 1.4 11.7 14.6 

 7 03/02/05 6341 9.9 1.2 11.0 13.2 

 8 03/09/05 6352 8.2 BDL 8.2 11.6 

 9 03/16/05 6364 6.8 BDL 6.8 9.4 

 10 03/23/05 6373 7.1 BDL 7.1 8.3 

 11 03/29/05 6381 6.1 BDL 6.1 7.0 

The stabilization data for Rig 1 on fuel E0 are listed in Table 15 and shown in Figure 35, and a similar 

presentation for Rig 2 follows in Table 16 and Figure 36. These rigs had been tested in the previous 

program with an E6 fuel (Fuel B), but had finished the program on the non-ethanol “Fuel C”, and were 

stored for the down time (roughly six months) with the non-ethanol fuel in their tanks. Rigs 11, 12 and 14 

did not show any ethanol in their measurements during the same time period. The measured levels were 

low, 5 mg/hour or less, but the source of the ethanol was not identified. 

Ethanol Impact - Stabilized Permeation

Rig 2 - E0 Fuel

0

10

20

30

40

50

60

Permeation - mg/hr

Total

Non-Ethanol HC

Ethanol

Rig 2, like Rig 1, also had a sudden 

appearance of ethanol in the results in 

the time period of 2-4-05 to 3-16-05. 

Figure 36 
52

Table 17 - 2000 Honda Odyssey Stabilization – Fuel E0 

Rig Fuel Week Date Test# NonEtOH EtOH 

NonEtOH 

+ EtOH 

Running 

Average

2 E0 01/11/05 Drain and 100% fill Fuel E0 

 0 01/12/05 6284 29.6 BDL 29.6 

 1 01/19/05 6294 47.6 BDL 47.6 

 1 01/20/05 6296 50.6 BDL 50.6 

 3 02/04/05 6309 39.8 8.8 48.6 44.1 

 4 02/09/05 6314 47.7 7.7 55.5 45.3 

 5 02/16/05 6326 47.8 7.9 55.7 51.9 

 02/18/05 Drain and 100% fill Fuel E0

 6 02/22/05 6330 46.9 5.5 52.4 53.1 

 7 03/02/05 6343 37.6 1.5 39.1 50.7 

 8 03/09/05 6354 41.7 0.7 42.4 47.4 

 9 03/16/05 6365 44.2 1.0 45.2 44.8 

 10 03/24/05 6375 43.4 BDL 43.4 42.5 

 11 03/30/05 6385 38.9 BDL 38.9 42.5 

That Rigs 1 and 2 had ethanol in their measured results at the same time, that later disappeared, can not be 

explained at this time. 

Ethanol can persist as an element of the permeation emissions of a fuel system long after use of the 

ethanol fuel has been discontinued. The results from the previous E-65 test program indicated the 

presence of ethanol in the permeate at a measurable level for a period of up to 7 weeks after the fuel had 

been changed to the non-ethanol fuel (Fuel C). It is thought that this “hang-up” is due to the time it takes 

for the permeation components to make their way through the various elastomers in the vehicle’s fuel 

system. Figure 37, representing the 10 rigs tested in the E-65 test program, is used to illustrate this effect. 

There appears to be a lingering presence of ethanol at levels of up to 5 mg/hour for a considerable period 

of time. 
53

The data used for this plot came from the original E-65 permeation test program, and represents the 

ethanol permeation measured after the switch from the 5.7% ethanol fuel evaluation (Fuel B) to the nonethanol fuel (Fuel C). The ten systems included in this analysis came from vehicle systems ranging from 

model year 1978 to 2001. All of the rigs exhibited “hang-up”, or carry-over of the ethanol component 

from the previous fuel, during the new stabilization period with the non-ethanol fuel.

Ethanol Decay

Fuel "C"

0

10

20

30

40

50

0 10 20 30 40 50

Test Time From Original Fill - days

Ethanol - mg

Figure 37