NREL/TP-540-43543 

 ORNL/TM-2008/117

Effects of Intermediate Ethanol Blends 

on Legacy Vehicles and Small 

Non-Road Engines, Report 1 – Updated 

February 2009 

Prepared by 

Keith Knoll 

Brian West 

Wendy Clark 

Ronald Graves 

John Orban 

Steve Przesmitzki 

Timothy Theiss 
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NREL/TP-540-43543 

ORNL/TM-2008/117 

EFFECTS OF INTERMEDIATE ETHANOL BLENDS ON LEGACY 

VEHICLES AND SMALL NON-ROAD ENGINES, 

REPORT 1 – UPDATED 

Keith Knoll,†

 Brian West,* Wendy Clark,† Ronald Graves,* John Orban,‡ 

Steve Przesmitzki,†

 and Timothy Theiss*

Date Published: February 2009 

Prepared by the 

National Renewable Energy Laboratory 

1617 Cole Boulevard, Golden, Colorado 80401-3393 

303-275-3000 • www.nrel.gov

NREL is a national laboratory of the U.S. Department of Energy 

Office of Energy Efficiency and Renewable Energy 

Operated by the Alliance for Sustainable Energy, LLC 

Contract No. DE-AC36-08-GO28308

*

Oak Ridge National Laboratory, Oak Ridge, Tennessee 

†

National Renewable Energy Laboratory, Golden, Colorado 

‡

Battelle Memorial Institute, Columbus, Ohio 

iii 

CONTENTS 

Page 

LIST OF FIGURES................................................................................................................................ v

LIST OF TABLES ................................................................................................................................ ix

ACRONYMS ..................................................................................................................................... xi

ACKNOWLEDGEMENTS ................................................................................................................xiii

FOREWORD ................................................................................................................................... xiv

EXECUTIVE SUMMARY.................................................................................................................. xv

1. INTRODUCTION ........................................................................................................................1-1

1.1 BACKGROUND ................................................................................................................1-1

1.2 TEST PROGRAM OVERVIEW ........................................................................................1-2

2. EXPERIMENTAL SETUP...........................................................................................................2-1

2.1 TEST FUELS AND ANALYSIS........................................................................................2-1

2.2 VEHICLES .........................................................................................................................2-2

2.2.1 Experimental Parameters .......................................................................................2-2

2.2.2 Statistical Analysis.................................................................................................2-6

2.3 SMALL NON-ROAD ENGINES.......................................................................................2-7

2.3.1 Experimental Parameters .......................................................................................2-7

3. RESULTS AND DISCUSSION...................................................................................................3-1

3.1 VEHICLES .........................................................................................................................3-1

3.1.1 Emissions and Fuel Economy Summary................................................................3-1

3.1.2 Exhaust and Catalyst Temperature Effects Summary............................................3-2

3.1.3 Unforeseen Operational Issues Summary ..............................................................3-2

3.1.4 Results and Discussion: Emissions and Fuel Economy.........................................3-2

3.1.5 Results and Discussion: Exhaust and Catalyst Temperature .................................3-6

3.1.6 Results and Discussion: Unforeseen Operational Issues........................................3-8

3.2 SMALL NON-ROAD ENGINES.......................................................................................3-9

3.2.1 Scope of Study .......................................................................................................3-9

3.2.2 Summary of Results .............................................................................................3-11

3.2.3 Results and Discussion: Engine Operation ..........................................................3-15

3.2.4 Results and Discussion: Emissions ......................................................................3-19

3.2.5 Results and Discussion: Exhaust, Oil, and Other Temperature Data...................3-23

4. NEXT STEPS ...............................................................................................................................4-1

4.1 EMISSIONS AND CATALYST TEMPERATURE ..........................................................4-1

4.2 EMISSIONS OF VARIOUS GASOLINES AND ETHANOL BLENDS..........................4-1

4.3 EVAPORATIVE EMISSIONS...........................................................................................4-1

4.4 FULL-USEFUL-LIFE EMISSIONS ..................................................................................4-1

4.5 DRIVEABILITY ................................................................................................................4-2

4.6 FUEL SYSTEM MATERIALS COMPATIBILITY ..........................................................4-2

4.7 FUTURE REPORTS...........................................................................................................4-2

APPENDIX A VEHIClE TEST EQUIPMENT, PROCEDURES, AND RELEVANT 

VEHICLE EMISSIONS STANDARDS..................................................................A-1

APPENDIX B SMALL NON-ROAD ENGINE TEST EQUIPMENT, PROCEDURES, 

AND RELEVANT EMISSIONS STANDARDS .................................................. B-1

APPENDIX C INDIVIDUAL VEHICLE EMISSIONS RESULTS ............................................... C-1

APPENDIX D SMALL ENGINE FULL-USEFUL-LIFE TESTING .............................................D-1

v 

LIST OF FIGURES 

Figure Page

3.1. Average percentage change in emissions and fuel economy for all vehicles compared 

to E0 fuel on the LA92 cycle. ................................................................................................3-4

3.2. Average change in ethanol and aldehyde emissions for all vehicles compared to E0 

fuel on the LA92 cycle. .........................................................................................................3-4

3.3. Average emissions and fuel economy for all vehicles on LA92 cycle. .................................3-5

3.4. Ethanol and aldehyde emissions for all vehicles on LA92 cycle. .........................................3-5

3.5. Change in catalyst temperature versus fuel type for wide-open throttle (WOT) openloop conditions. ......................................................................................................................3-8

3.6. Exhaust temperature increase for all small non-road engines tested in the new and fulluseful-life (full-life) condition with ethanol blends, as compared to E0 baseline. ..............3-12

3.7. Average change in emissions for all small non-road engines tested in the new (top 

chart) and full-useful-life (full-life) (bottom chart) condition with ethanol blends, as 

compared to E0 baseline. .....................................................................................................3-13

3.8. Poulan leaf blower engine speed versus time for fuels E0 through E20. .............................3-16

3.9. Aging timeline for five Weed Eater Featherlite blowers......................................................3-18

3.10. Stihl owner’s manual schematic showing location of high-speed (H), low-speed (L), 

and low-idle (LA) adjustment screws. .................................................................................3-19

3.11. Hydrocarbon (HC) emissions for pilot study engines versus fuel ethanol content. ............3-21

3.12. Nitrogen oxide (NOX) emissions for pilot study engines versus fuel ethanol content. . ......3-21

3.13. Hydrocarbon (HC) + nitrogen oxide (NOX) emissions for pilot study engines. ..................3-22

3.14. Carbon monoxide emissions for pilot study engines. ..........................................................3-22

3.15. Exhaust port temperature for pilot study engines at hottest condition versus ethanol 

blend level. ...........................................................................................................................3-29

3.16. Exhaust temperature versus mode for all fuels and individual cylinders of Kohler 

generator. .............................................................................................................................3-29

3.17. Individual cylinder CO concentration for E0 fueling at three loads for Kohler 

generator...............................................................................................................................3-30

3.18. Exhaust port temperature for Briggs and Stratton power washer engines at mode 6 

condition versus ethanol blend level. ..................................................................................3-33

3.19. Exhaust port temperature for Class IV Stihl line trimmer engines at hottest condition 

(mode 1) at new and full-useful-life (full-life) condition. ...................................................3-33

A.1. Example of vehicle exhaust system instrumentation, including universal exhaust gas 

oxygen sensor (UEGO) and temperature and exhaust gas sample ports...............................A-3

A.2. LA92 drive cycle...................................................................................................................A-5

A.3. Modified Coordinating Research Council E-60 wide-open-throttle drive cycle...................A-7

A.4. Wide-open-throttle (WOT) hill climb and edge of fuel enrichment drive cycle with 

vehicle speed data from 2007 Buick. ....................................................................................A-8

C.1. Non-methane organic gas (NMOG), non-methane hydrocarbons (NMHC), carbon 

monoxide (CO), oxides of nitrogen (NOX), and fuel economy (FE) for 2007 Chrysler 

Town and Country on LA92 cycle.. ...................................................................................... C-2

C.2. Ethanol, acetaldehyde, and formaldehyde emissions for 2007 Chrysler Town and 

Country on LA92 cycle.. ....................................................................................................... C-2

C.3. Non-methane organic gas (NMOG), non-methane hydrocarbons (NMHC), carbon 

monoxide (CO), oxides of nitrogen (NOX), and fuel economy (FE) for 2007 Ford F150 

on LA92 cycle.. ..................................................................................................................... C-3
vi 

C.4. Ethanol, acetaldehyde, and formaldehyde emissions for 2007 Ford F150 on LA92 

cycle.. .................................................................................................................................... C-3

C.5. Non-methane organic gas (NMOG), non-methane hydrocarbons (NMHC), carbon 

monoxide (CO), oxides of nitrogen (NOX), and fuel economy (FE) for 2003 Ford F150 

on LA92 cycle.. ..................................................................................................................... C-4

C.6. Ethanol, acetaldehyde, and formaldehyde emissions for 2003 Ford F150 on LA92 

cycle. ..................................................................................................................................... C-4

C.7. Non-methane organic gas (NMOG), non-methane hydrocarbons (NMHC), carbon 

monoxide (CO), oxides of nitrogen (NOX), and fuel economy (FE) for 2003 Ford 

Taurus on LA92 cycle.. .........................................................................................................C-5

C.8. Ethanol, acetaldehyde, and formaldehyde emissions for 2003 Ford Taurus on LA92 

cycle.. .................................................................................................................................... C-5

C.9. Non-methane organic gas (NMOG), non-methane hydrocarbons (NMHC), carbon 

monoxide (CO), oxides of nitrogen (NOX), and fuel economy (FE) for 2007 Buick 

Lucerne on LA92 cycle.. ....................................................................................................... C-6

C.10. Ethanol, acetaldehyde, and formaldehyde emissions for 2007 Buick Lucerne on LA92 

cycle.. .................................................................................................................................... C-6

C.11. Non-methane organic gas (NMOG), non-methane hydrocarbons (NMHC), carbon 

monoxide (CO), oxides of nitrogen (NOX), and fuel economy (FE) for 2003 Buick 

LeSabre on LA92 cycle......................................................................................................... C-7

C.12. Ethanol, acetaldehyde, and formaldehyde emissions for 2003 Buick LeSabre on LA92 

cycle. ..................................................................................................................................... C-7

C.13. Non-methane organic gas (NMOG), non-methane hydrocarbons (NMHC), carbon 

monoxide (CO), oxides of nitrogen (NOX), and fuel economy (FE) for 2007 Chevrolet 

Silverado on LA92 cycle....................................................................................................... C-8

C.14. Ethanol, acetaldehyde, and formaldehyde emissions for 2007 Chevrolet Silverado on 

LA92 cycle.. .......................................................................................................................... C-8

C.15. Non-methane organic gas (NMOG), non-methane hydrocarbons (NMHC), carbon 

monoxide (CO), oxides of nitrogen (NOX), and fuel economy (FE) for 2007 Honda 

Accord on LA92 cycle.. ........................................................................................................ C-9

C.16. Ethanol, acetaldehyde, and formaldehyde emissions for 2007 Honda Accord on LA92 

cycle. ..................................................................................................................................... C-9

C.17. Non-methane organic gas (NMOG), non-methane hydrocarbons (NMHC), carbon 

monoxide (CO), oxides of nitrogen (NOX), and fuel economy (FE) for 2003 Nissan 

Altima on LA92 cycle. Bars show average of 3 tests at 75°F............................................. C-10

C.18. Ethanol, acetaldehyde, and formaldehyde emissions for 2003 Nissan Altima on LA92 

cycle.. .................................................................................................................................. C-10

C.19. Non-methane organic gas (NMOG), non-methane hydrocarbons (NMHC), carbon 

monoxide (CO), oxides of nitrogen (NOX), and fuel economy (FE) for 2007 Toyota 

Camry on LA92 cycle. ........................................................................................................ C-11

C.20. Ethanol, acetaldehyde, and formaldehyde emissions for 2007 Toyota Camry on LA92 

cycle.. .................................................................................................................................. C-11

C.21. Non-methane organic gas (NMOG), non-methane hydrocarbons (NMHC), carbon 

monoxide (CO), oxides of nitrogen (NOX), and fuel economy (FE) for 2003 Toyota 

Camry on LA92 cycle. ........................................................................................................ C-12

C.22. Ethanol, acetaldehyde, and formaldehyde emissions for 2003 Toyota Camry on LA92 

cycle.. .................................................................................................................................. C-12

C.23. Non-methane organic gas (NMOG), non-methane hydrocarbons (NMHC), carbon 

monoxide (CO), oxides of nitrogen (NOX), and fuel economy (FE) for 2001 Chrysler 

PT Cruiser on LA92 cycle................................................................................................... C-13
vii 

C.24. Ethanol, acetaldehyde, and formaldehyde emissions for 2001 Chrysler PT Cruiser on 

LA92 cycle.. ........................................................................................................................ C-13

C.25. Non-methane organic gas (NMOG), non-methane hydrocarbons (NMHC), carbon 

monoxide (CO), oxides of nitrogen (NOX), and fuel economy (FE) for 1999 Ford 

Crown Victoria on LA92 cycle.. ......................................................................................... C-14

C.26. Ethanol, acetaldehyde, and formaldehyde emissions for 1999 Ford Crown Victoria on 

LA92 cycle.. ........................................................................................................................ C-14

C.27. Non-methane organic gas (NMOG), non-methane hydrocarbons (NMHC), carbon 

monoxide (CO), oxides of nitrogen (NOX), and fuel economy (FE) for 1999 Honda 

Civic on LA92 cycle............................................................................................................ C-15

C.28. Ethanol, acetaldehyde, and formaldehyde emissions for 1999 Honda Civic on LA92 

cycle.. .................................................................................................................................. C-15

C.29. Non-methane organic gas (NMOG), non-methane hydrocarbons (NMHC), carbon 

monoxide (CO), oxides of nitrogen (NOX), and fuel economy (FE) for 1999 Toyota 

Corolla on LA92 cycle. ....................................................................................................... C-16

C.30. Ethanol, acetaldehyde, and formaldehyde emissions for 1999 Toyota Corolla on LA92 

cycle.. .................................................................................................................................. C-16

C.31. Non-methane organic gas (NMOG), non-methane hydrocarbons (NMHC), carbon 

monoxide (CO), oxides of nitrogen (NOX), and fuel economy (FE) for 2004 

Volkswagen Golf GTI on LA92 cycle.. .............................................................................. C-17

C.32. Ethanol, acetaldehyde, and formaldehyde emissions for 2004 Volkswagen Golf GTI 

on LA92 cycle. .................................................................................................................... C-17

D.1. Hydrocarbon (HC) emissions for Class I Briggs and Stratton power washer engines on 

Transportation Research Center protocol at new and full-useful-life (full-life) 

condition................................................................................................................................D-1

D.2. Nitrogen oxide (NOX) emissions for Class I Briggs and Stratton power washer engines 

on the Transportation Research Center protocol at new and full-useful-life (full-life) 

condition................................................................................................................................D-2

D.3. Hydrocarbon (HC) + nitrogen oxide (NOX) emissions for Class I Briggs and Stratton 

power washer engines on the Transportation Research Center protocol at new and fulluseful-life (full-life) condition...............................................................................................D-2

D.4. Carbon monoxide emissions for Class I Briggs and Stratton power washer engines on 

the Transportation Research Center protocol at new and full-useful-life (full-life) 

condition................................................................................................................................D-3

D.5. Hydrocarbon (HC) emissions for Class I Briggs and Stratton power washer engines on 

the Briggs and Stratton Company (BASCO) protocol. .........................................................D-3

D.6. Nitrogen oxide (NOX) emissions for Class I Briggs and Stratton power washer engines 

on the Briggs and Stratton Company (BASCO) protocol at new and full-useful-life 

(full-life) condition................................................................................................................D-4

D.7. Hydrocarbon (HC) + nitrogen oxide (NOX) emissions for Class I Briggs and Stratton 

power washer engines on the Briggs and Stratton Company (BASCO) protocol at new 

and full-useful-life (full-life) condition.................................................................................D-4

D.8. Carbon monoxide emissions for Class I Briggs and Stratton power washer engines on 

the Briggs and Stratton Company (BASCO) protocol at new and full-useful-life (fulllife) condition. .......................................................................................................................D-5

D.9. Hydrocarbon (HC) emissions for Class I Honda generator engines at new and 

full-useful-life (full-life) condition........................................................................................D-5

D.10. Nitrogen oxide (NOX) emissions for Class I Honda generator engines at new and 

full-useful-life (full-life) condition........................................................................................D-6

D.11. Hydrocarbon (HC) + nitrogen oxide (NOX) emissions for Class I Honda generator 

engines at new and full-useful-life (full-life) condition. ......................................................D-6
viii 

D.12. Carbon monoxide emissions for Class I Honda generator engines at new and 

full-useful-life (full-life) condition........................................................................................D-7

D.13. Hydrocarbon (HC) emissions for Class IV Weed Eater blower engines at new and 

full-useful-life (full-life) condition. ......................................................................................D-7

D.14. Nitrogen oxide (NOX) emissions for Class IV Weed Eater blower engines at new and 

full-useful-life (full-life) condition........................................................................................D-8

D.15. Hydrocarbon (HC) + nitrogen oxide (NOX) emissions for Class IV Weed Eater blower 

engines at new and full-useful-life (full-life) condition. ......................................................D-8

D.16. Carbon monoxide emissions for Class IV Weed Eater blower engines at new and 

full-useful-life (full-life) condition........................................................................................D-9

D.17. Hydrocarbon (HC) emissions for Class IV Stihl line trimmer engines at new and 

full-useful-life (full-life) condition. ......................................................................................D-9

D.18. Nitrogen oxide (NOX) emissions for Class IV Stihl line trimmer engines at new and 

full-useful-life (full-life) condition. ...................................................................................D-10

D.19. Hydrocarbon (HC) + nitrogen oxide (NOX) emissions for Class IV Stihl line trimmer 

engines at new and full-useful-life (full-life)condition. .....................................................D-10

D.20. Carbon monoxide emissions for Class IV Stihl line trimmer engines at new and 

full-useful-life (full-life) condition. ....................................................................................D-11

D.21. Exhaust port temperature for Class I Briggs and Stratton power washers at mode 6 

(fast idle) at new and full-useful-life (full-life) condition.. .................................................D-18

D.22. Exhaust port temperature for Class I Honda generators at mode 6 (fast idle) at new and 

full-useful-life (full-life) condition......................................................................................D-19

D.23. Exhaust port temperature for Class IV Weed Eater Featherlite blower engines at mode 

1 (full power) at new and full-useful-life (full-life) condition. ..........................................D-19

D.24. Exhaust port temperature for Class IV Stihl line trimmers at mode 1 (full power) at 

new and full-useful-life (full-life) condition. .....................................................................D-20
ix 

LIST OF TABLES 

Table Page

 2.1. Test fuel property measurements.....................................................................................2-1

 2.2. Test fuel properties ..........................................................................................................2-2

 2.3. Number of registered gasoline-powered vehicles in the United States on 

January 1, 2007—by model year period, manufacturer, and number of cylinders..........2-3

 2.4. Test vehicle list ................................................................................................................2-5

 2.5. Small non-road engine classification descriptions per 40 CFR 90 ..................................2-7

 2.6. SNRE equipment tested in pilot and full-useful-life (full-life) studies............................2-9

 2.7. ISO 8178 emission test cycles .........................................................................................2-9

 3.1. Estimated change (% or mg/mi) in emissions and fuel economy relative to E0 

with ±95% confidence limit.............................................................................................3-3

 3.2. Number of vehicles with positive changes in emissions and fuel economy relative 

to E0 among 16 test vehicles ...........................................................................................3-6

 3.3. SNRE classification descriptions per 40 CFR 90 ............................................................3-9

 3.4. SNRE equipment tested in pilot and full-useful-life (full-life) studies..........................3-10

 3.5. Summary of engine operational problems at ORNL, NREL, and TRC.........................3-14

 3.6. Summary of engine, fuel, and emissions test protocols for full-useful-life (fulllife) testing Hashed areas indicate no data collected. Fuel column denotes fuel 

tested at that condition (E0, E10, E15, or E20)..............................................................3-17

 3.7. Baseline E0 emissions and relative change for E10, E15, and E20 for pilot study 

engines ...........................................................................................................................3-20

 3.8. Baseline Briggs and Stratton power washer engine emissions on the TRC 

protocol at new and full-useful-life (full-life) condition with E0 fuel, and relative 

change for respective ethanol blends .............................................................................3-24

 3.9. Briggs and Stratton power washer engine emissions on the BASCO protocol at 

new and full-useful-life (full-life) condition with E0 fuel, and relative change for 

respective ethanol blends ...............................................................................................3-25

 3.10. Baseline Honda generator engine emissions at new and full-useful-life (full-life) 

condition with E0 fuel, and relative change for respective ethanol blends....................3-26

 3.11. Baseline Weed Eater Featherlite blower engine emissions at new and full-usefullife (full-life) condition with EO fuel, and relative change for respective ethanol 

blends.............................................................................................................................3-27

 3.12. Baseline Stihl line trimmer engine emissions at new and full-useful-life (full-life) 

condition with E0 fuel, and relative change for respective ethanol blends....................3-28

 3.13. Change in exhaust temperature with ethanol blends for hottest engine condition 

for six pilot study engines..............................................................................................3-28

 3.14. Change in exhaust temperature for engines in full-useful-life (full-life) study for 

hottest engine condition. ................................................................................................3-32

 A.1. Federal certification exhaust emission standards for light-duty vehicles 

and light-duty trucks .....................................................................................................A-11

 A.2. Footnotes used in Table A.1 .........................................................................................A-12

 A.3. Acronyms used in Tables A.1, A.4, and A.5 ................................................................A-13

 A.4. Tier 2 and interim non-Tier 2 full-useful-life exhaust emissions standards .................A-14

 A.5. Tier 2 and interim non-Tier 2 intermediate full-useful-life (50,000 mile) exhaust 

emissions standards.......................................................................................................A-14

 B.1 ISO 8178 emission test cycles ........................................................................................ B-2
x 

 B.2. Summary of engine, fuel, and emissions test protocols for full-useful-life (fulllife) testing ...................................................................................................................... B-7

 B.3. Phase 1 and Phase 2 non-handheld engine emission standards .................................... B-10

 B.4. Phase 1 and Phase 2 handheld engine emission standards............................................ B-11

 B.5. Full useful life periods for Phase 2 SNREs .................................................................. B-11

 C.1. List of Appendix C figures ............................................................................................. C-1

 D.1. Briggs and Stratton power washer baseline E0 emissions on the TRC protocol, 

 at new (after initial break-in) condition, and at full-useful-life 

(full-life) condition .......................................................................................................D-12

 D.2. Briggs and Stratton power washer emissions on the TRC protocol in new 

and full-useful-life (full-life) condition with respective ethanol blends .......................D-13

 D.3. Briggs and Stratton power washer emissions on the BASCO protocol, E0 and 

ethanol blends ...............................................................................................................D-14

 D.4. Honda generator emissions at new and full-useful-life (full-life) condition, E0 

baseline and respective ethanol blends .........................................................................D-15

 D.5. Weed Eater Featherlite blower emissions at new and full-useful-life (full-life) 

condition, E0 baseline and respective ethanol blends...................................................D-16

 D.6. Stihl line trimmer emissions, new and full-useful-life (full-life) condition, E0 

baseline and respective ethanol blends .........................................................................D-17
xi 

ACRONYMS 

ALDL Assembly Line Diagnostic Link 

ANL Argonne National Laboratory 

BASCO Briggs and Stratton Company (usually in reference to the Briggs and Stratton 

emissions testing protocol) 

CDPHE Colorado Department of Public Health and Environment 

CFR Code of Federal Regulations 

CA LEV II California Low Emission Vehicle 2 

CO carbon monoxide 

COV coefficient of variation 

CRC Coordinating Research Council 

DOE U.S. Department of Energy 

DVPE dry vapor pressure equivalent 

ECU Engine Control Unit 

EERE Office of Energy Efficiency and Renewable Energy (DOE) 

EGO exhaust gas oxygen 

EPA U.S. Environmental Protection Agency 

EtOH ethanol 

FFV flexible-fuel vehicle 

FID flame ionization detector (instrument for measurement of HC emissions) 

full life full, useful life 

H high speed (mixture adjustment on Stihl line trimmer) 

HC hydrocarbon 

L low speed (mixture adjustment on Stihl line trimmer) 

LA low idle (idle speed adjustment on Stihl line trimmer) 

LBT lean best torque 

LEV low-emission vehicle 

LHV lower heating value 

MIL malfunction indicator light 

NMHC non-methane hydrocarbons 

NMOG non-methane organic gas 

NOX oxides of nitrogen/nitrogen oxides [nitric oxide (NO) and nitrogen dioxide (NO2)] 

NREL National Renewable Energy Laboratory 

OBDII onboard diagnostic 

OEM original equipment manufacturer 

ORNL Oak Ridge National Laboratory 

PM particulate matter 

RFA Renewable Fuels Association (Minnesota) 

RFS renewable fuel standard 

RIT Rochester Institute of Technology 

RVP Reid vapor pressure 

SAS Statistical Analysis System (software package) 

SG specific gravity 

SNRE small, non-road engine 

SRC standard road cycle 

THC total hydrocarbon 

TLEV transitional low-emission vehicle 

TRC Transportation Research Center 

UEGO universal exhaust gas oxygen (sensor) 
xii 

ULEV ultra-low-emission vehicle 

USCAR United States Council for Automotive Research 

WOT wide-open throttle 
xiii 

ACKNOWLEDGEMENTS 

This report and the work described were sponsored by the U.S. Department of Energy (DOE) 

Office of Energy Efficiency and Renewable Energy (EERE) Biomass Program and the EERE Vehicle 

Technologies Program. The authors gratefully acknowledge the support and editorial guidance of 

Joan Glickman and Kevin Stork at DOE. Assistance in the project management of this report from 

Carolyn Clark of BCS, Inc., is also greatly appreciated. This work has also benefited from substantial 

input and direction from numerous peers within the U.S. Council for Automotive Research, the 

Outdoor Power Equipment Institute, and the Environmental Protection Agency. We acknowledge and 

appreciate the thorough review and input from Rich Bechtold and Tom Timbario of Alliance 

Technical Services. Several Oak Ridge National Laboratory staff made important contributions to this 

work, including Shean Huff, John Thomas, Kevin Norman, Larry Moore, Ron Lentz, John Storey, 

Sam Lewis, and Teresa Barone. Likewise, several National Renewable Energy Laboratory staff made 

equally important contributions, including Colleen Alexander, Lisa Fouts, Jon Luecke, Robert 

McCormick, and Matt Ratcliff. Assistance with management and statistical analysis of the vehicle 

data by Cynthia Cooper, Bryan Fair, Tony Fristachi, and Marcie Mohnsen at Battelle is appreciated. 

The authors are also indebted to the staff of the Colorado State Emissions Laboratory, in particular 

Steve Sargent, Jim Kemper, Mike Mallory, Thad Pyzdrowski, and Mike Waida. Grateful 

acknowledgment is also due to Transportation Research Center, Inc. (TRC), especially Walt Dudek 

and Jason Holmes for their professional vehicle and small engine testing, and Steve McConnell at 

Argonne National Laboratory for his support of some of the vehicle testing at TRC. The authors also 

wish to thank the peer review panel led by Joseph Colucci for their thorough review and constructive 

recommendations and Brenda Smith, V. J. Ewing, Paula Pitchford, and Irene Passage for their 

dedication in preparation of the final manuscript. 

The authors are indebted to many technical experts in industry and other government agencies. 

While these experts provided valuable guidance and information as noted above, this consultation 

does not constitute endorsement by their organizations of either the study or the results. 
xiv 

FOREWORD 

This report is an update of the original version, which was published in October 2008. This 

updated report includes results from the complete 16-vehicle fleet (the original report included only 

the first 13 vehicles tested) as well as corrections to minor errors identified in some of the originally 

reported data. Conclusions drawn from the complete dataset are nearly identical to those from the 

original 13-vehicle fleet but with increased statistical confidence. Significant changes to the report 

content are as follows: 

• Summary results of vehicle emissions changes with ethanol content are updated and show 

improved statistical confidence. 

• Tabulated vehicle emissions results (Tables 3.1 and 3.2) are updated to reflect results for the 

complete 16-vehicle fleet. Observed results are largely unchanged, but statistical confidence 

is improved. 

• Charted vehicle emissions results (Figures 3.1 thru 3.4) are updated to reflect results for the 

complete 16-vehicle fleet. These results now include three additional older emissions 

classification vehicles with (generally) higher pollutant emissions. 

• Charted vehicle emissions results included in Appendix C are updated for all vehicles; results 

for the three additional vehicles are added, and minor errors in the original 13-vehicle fleet 

are corrected. 
xv 

EXECUTIVE SUMMARY 

E.1 IMPACT OF INTERMEDIATE ETHANOL BLENDS ON LEGACY VEHICLES 

AND ENGINES 

In summer 2007, the U.S. Department of Energy (DOE) initiated a test program to evaluate 

the potential impacts of intermediate ethanol blends on legacy vehicles and other engines.*

 The 

purpose of the test program is to assess the viability of using intermediate blends as a contributor 

to meeting national goals in the use of renewable fuels. Through a wide range of experimental 

activities, DOE is evaluating the effects of E15 and E20—gasoline blended with 15% and 20% 

ethanol—on tailpipe and evaporative emissions, catalyst and engine durability, vehicle 

driveability, engine operability, and vehicle and engine materials. 

This first report provides the results available to date from the first stages of a much larger 

overall test program. Results from additional projects that are currently underway or in the 

planning stages are not included in this first report. The purpose of this initial study was to 

quickly investigate the effects of adding up to 20% ethanol to gasoline on the following. 

• Regulated tailpipe emissions for 16 popular late-model vehicles on a drive cycle similar to 

real-world driving and 28 small non-road engines (SNREs)†

 under certification or typical inuse procedures.

• Exhaust and catalyst temperatures of the same vehicles under more severe conditions. 

• Temperature of key engine components of the same SNREs under certification or typical 

in-use conditions. 

• Observable operational issues with either the vehicles or SNREs during the course of testing. 

As discussed in the concluding section of this report, a wide range of additional studies are 

underway or planned to consider the effects of intermediate ethanol blends on materials, 

emissions, durability, and driveability of vehicles, as well as impacts on a wider range of nonautomotive engines, including marine applications, snowmobiles, and motorcycles. 

Section 1 (Introduction) provides background on the test program and describes 

collaborations with industry and agencies to date. Section 2 (Experimental Setup) provides details 

concerning test fuels, vehicle and SNRE selection, and test methods used to conduct the studies 

presented in this report. Section 3 (Results and Discussion) summarizes the vehicle and SNRE 

studies and presents data from the testing completed to date. Section 4 (Next Steps) describes 

planned future activities. The appendixes provide test procedure details, vehicle and SNRE 

emissions standards, analysis details, and additional data and tables from vehicle and SNRE tests. 

E.2 BACKGROUND 

The Energy Independence and Security Act of 2007 calls on the nation to significantly 

increase its use of renewable fuels to meet its transportation energy needs. The law expands the 

renewable fuel standard (RFS) to require the use of 36 billion gallons of renewable fuel by 2022. 

Given that ethanol is the most widely used renewable fuel in the U.S. market, ethanol will likely 

make up a significant portion of the 36-billion-gallon requirement. 

 *

The test program is co-led and funded by the DOE Office of Energy Efficiency and Renewable Energy (EERE) 

Biomass Program and the EERE Vehicle Technologies Program with technical support from the Oak Ridge National 

Laboratory and the National Renewable Energy Laboratory. DOE and the laboratory team have worked closely with 

representatives from the U.S. Environmental Protection Agency, U.S. auto manufacturers, engine companies, and other 

organizations to develop and conduct a robust test program. 

† Ten different equipment models were tested, with multiple copies tested in some cases for a total of 28 engines. 
xvi 

The vast majority of ethanol used in the United States is blended with gasoline to create 

E10—gasoline with up to 10% ethanol. The remaining ethanol is sold in the form of E85—a 

gasoline blend with as much as 85% ethanol that can be used only in flexible-fuel vehicles 

(FFVs). Consumption of E85 is currently limited by both the size of the flex-fuel vehicle fleet and 

the number of E85 fueling stations. 

Given projected growth in ethanol production and the new RFS, most analysts agree that the 

E10 market will be saturated in the next few years, possibly as soon as 2010. Although DOE 

remains committed to expanding the E85 infrastructure, that market represented less than 1% of 

the ethanol consumed in 2007 and will not be able to absorb projected volumes of ethanol in the 

near term. Given this reality, DOE and others have begun assessing the viability of using 

intermediate ethanol blends as a way to accommodate growing volumes of ethanol. 

E.3 DEVELOPMENT OF TEST PROGRAM 

The DOE team [DOE, the National Renewable Energy Laboratory (NREL), and the Oak 

Ridge National Laboratory (ORNL)] has collaborated with industry and other experts regarding 

the development and implementation of the test program. A number of automotive and non-road 

engine manufacturers provided significant input into the test protocols. This collaboration was 

typically coordinated through industry organizations such as the U.S. Council for Automotive 

Research, the Coordinating Research Council (CRC), the Outdoor Power Equipment Institute, the 

Alliance of Automobile Manufacturers, and the Association of International Automobile 

Manufacturers. Staff at the U.S. Environmental Protection Agency (EPA) provided important 

guidance in helping DOE design tests and select sample vehicles and small engines based on 

sales volumes and related test programs. In addition, statistical experts at Battelle Memorial 

Institute assisted in the vehicle selection process and data analysis. Argonne National Laboratory 

also assisted in data collection. DOE expects to continue to work closely with industry on 

ongoing and future tests. 

Close interactions with representatives from the affected industries and EPA have been 

particularly helpful in refining or developing test protocols to assess the impact of intermediate 

ethanol blends on the equipment being tested. With respect to the specific studies presented in 

this report, standard test procedures were used where possible; however, in many cases, test 

protocols had to be modified or created where they did not yet exist. 

E.4 SUMMARY OF VEHICLE TESTS AND DATA 

For the studies documented in this report, vehicles were selected based on manufacturer, 

engine configuration and displacement, emission control system evolution, and model year. An 

initial group of 11 vehicles was selected primarily to span the evolution of emission control 

system technology and focused on two model years, 2003 and 2007. Five additional popular 

model vehicles were selected from a set of vehicles identified by the Coordinating Research 

Council (CRC) as particularly likely to be sensitive to increased ethanol content in gasoline.*

These five vehicles included three 1999 models, one 2001 model, and one 2004 model. All of the 

vehicles were tested on federal certification gasoline (E0), E10, E15, and E20—that is, gasoline 

and three different gasoline/ethanol blends. Due to time constraints in obtaining match-blended 

fuels, splash blends were used in this study—that is, the E0 certification fuel was simply diluted 

with appropriate amounts of fuel-grade ethanol. Match-blended and splash-blended fuels have 

different hydrocarbon (HC) and volatility characteristics. While the different fuel characteristics 

 *

The CRC Emissions Committee identified several vehicles suspected of not applying long-term fuel trim under 

high-load, open-loop conditions (http://www.crcao.com/doingbusiness/recentRFP.html, CRC Project No. E-87-1). 

Further details are in Sect. 2.2.1.1. 
xvii 

were not expected to have a significant impact on the temperature measurements, the emissions 

results may have been influenced slightly by unintended changes in the vehicle cold start and 

warm up. The effect of different fuel characteristics on vehicle tailpipe emissions is currently 

being examined in a separate DOE–EPA jointly sponsored project. 

E.4.1 Fuel Economy 

• All 16 vehicles exhibited a loss in fuel economy commensurate with the energy density of the 

fuel.*

 With E20, the average reduction in fuel economy (i.e., the reduction in miles per 

gallon) was 7.7% when compared to E0. 

• Limited evaluations of fuel with as much as 30% ethanol were conducted, and the reduction 

in miles per gallon continued as a linear trend with increasing ethanol content. 

E.4.2 Emissions 

• Regulated tailpipe emissions remained largely unaffected by the ethanol content of the fuel. 

• As ethanol content increased, 

⎯ oxides of nitrogen (NOX) and non-methane organic gases (NMOG) showed no significant 

change; 

⎯ non-methane hydrocarbons and carbon monoxide (CO) emissions declined on average for 

all ethanol blend levels tested. Neither pollutant changed appreciably from E10 to E20; 

⎯ ethanol emissions increased; 

⎯ acetaldehyde emissions increased; 

⎯ formaldehyde emissions increased slightly; and 

⎯ benzene and 1,3-butadiene were expected to decrease due to dilution, but measurements 

were conducted on only a subset of the vehicles and have not been thoroughly analyzed 

to date. 

E.4.3 Catalyst Temperatures 

• At closed-loop operating conditions, catalyst temperatures were cooler or unchanged with 

higher levels of ethanol. 

• Nine of the 16 tested vehicles adjusted fueling with increased ethanol content to maintain a 

consistent fuel:air equivalence ratio†

 at wide-open throttle (WOT).‡ In these cases, the 

catalyst temperatures at equivalent operating conditions were lower or unchanged with 

ethanol. 

• Seven of the 16 tested vehicles ran leaner§

 (albeit still rich) with E20 fuel than with E0 fuel at 

WOT. For these vehicles, catalyst temperatures at WOT were between 29oC and 35oC higher 

with E20 relative to E0. 

 *

This result was expected because ethanol has about 67% of the energy density of gasoline on a volumetric basis. 

†

Equivalence ratio is a measure of the actual fuel to air (oxidizer) compared to stoichiometric conditions. 

“Stoichiometric” is the condition in which 100% of both fuel and air are consumed in the combustion reaction, 

resulting in no excess oxygen or unburned fuel. 

‡

Wide-open throttle (WOT) is the full power condition for spark-ignition engines and is often an open-loop 

condition. 

§

“Lean” refers to a condition in which 100% of the fuel is consumed, but excess oxygen remains after the reaction. 

“Rich” refers to a condition in which 100% of the air is consumed, but excess unburned fuel remains after combustion. 
xviii 

E.4.4 Operability 

Although formal driveability testing was not conducted during the testing reported here, no 

operability or driveability issues were identified when any of the ethanol blends were used during 

the limited time of the project. Each vehicle accumulated at least 100 miles on each ethanol 

blend, and at least 200 miles on gasoline (E0 fuel). Mileage accumulations for the vehicles ranged 

from 500–1,200 miles due to additional tests on some of the vehicles. The following observations 

were noted during the limited test period. 

• None of the vehicles displayed a malfunction indicator light (MIL) as a result of the ethanol 

content of the fuel. 

• No fuel filter plugging symptoms were observed. 

• No cold start problems were observed in 75°F and 50°F laboratory conditions. 

• No fuel leaks or conspicuous degradation of the fuel systems were observed. 

E.5 SUMMARY OF SMALL NON-ROAD ENGINE TESTS AND DATA 

Millions of SNREs are sold each year, including leaf blowers and line trimmers, lawn 

mowers, generator sets, and small tractors (all under 25 hp). EPA certifies on the order of 900 

engine emission “families” for SNREs each year. Unlike the engines in modern light-duty 

vehicles, SNREs are typically open-loop engines—that is, these engines do not have exhaust 

oxygen sensing capabilities and therefore cannot compensate for ethanol content in the fuel. 

These open-loop engines are commonly air-cooled, and they customarily operate fuel-rich to 

achieve cooler combustion temperatures for longevity purposes. With a fixed fueling calibration, 

as ethanol content in the fuel increases, combustion becomes leaner, leading to higher combustion 

temperatures and higher component temperatures, as well as changes in emissions and sometimes 

idle speed. 

Initial tests conducted by ORNL and NREL focused on identifying emissions or operational 

issues and measurement of several key engine temperatures with federal certification gasoline 

(E0) and three splash-blended fuels (E10, E15, and E20). One copy of each engine was tested on 

all four fuels in this pilot study. 

In addition to the ORNL and NREL tests, DOE funded the Transportation Research Center 

(TRC) through an ORNL subcontract to test four copies of several small engines to full useful life 

(full life). All of these engines were tested on E0 and then aged on a dedicated fuel—E0, E10, 

E15, or E20. The tests performed at TRC measured emissions and temperatures at various stages 

of the engines’ lives—when new, at half life, and at full life. The primary focus of these tests was 

to assess any operational problems during aging to full life and to evaluate how engine operation 

and emissions change over time with exposure to various levels of ethanol. 

Similar to the vehicle tests, splash-blended fuels were used in this study instead of matchblended fuels—that is, the E0 fuel was simply diluted with appropriate amounts of ethanol. 

Similar to the vehicle results, the different fuel characteristics of match-blended and splashblended fuels were not expected to have a significant impact on temperature. In addition, the 

emission results for the SNRE testing are not expected to vary significantly between splashblended and match-blended fuels because a cold start and warm up were not included in the 

testing. 
xix 

E.5.1 Emissions 

Results from the tests of 28 SNREs generally indicated that, as ethanol content increased to 

as much as 20%, open-loop engines operated leaner with increasing ethanol. Effects of this 

enleanment*

 on emissions included the following. 

• NOX emissions increased. 

• HC emissions generally decreased. 

• Regulated emissions—combined HC + NOX—decreased in most cases. 

• CO emissions decreased. 

E.5.2 Performance and Operability 

The following observations were noted during testing of the small, open-loop engines. 

• With greater ethanol content, temperatures of the exhaust components, cylinder head, and 

cylinders generally increased. The largest increases were in exhaust temperature, rising 10°C 

to 50°C from E0 to E15 and 20°C to 70°C from E0 to E20. For the six engines in the pilot 

study in which temperatures were measured on all four fuels for each engine, temperature 

increases from E10 to E15 ranged between 5°C and 10°C. 

• With greater ethanol content, three handheld trimmers demonstrated higher idle speed and 

experienced unintentional clutch engagement. The increased speed was again caused by the 

fuel:air mixture enleanment, which can be adjusted and mitigated in some engines. 

• Residential and Commercial Class I and Class IV engines were aged to full life. The 

residential Class I as well as the commercial engines exhibited no sensitivity to ethanol from 

a durability perspective. The effect of ethanol on durability of the residential Class IV engines 

was not clear, given that a number of these engines failed during full-life aging regardless of 

fuel type. The failure of these engines may have been related to the engine mounting method. 

• Although not specifically characterized, no obvious materials compatibility issues were noted 

during the limited duration of this program. 

• In the case of the 2-cylinder engine tested, temperatures and emissions varied from cylinder 

to cylinder due to differences in the air-fuel distribution between cylinders. Given this 

observation, multicylinder open-loop engines may prove to be more sensitive to ethanol 

blends. 

 *

Enleanment means moving toward a leaner fuel:air equivalence ratio. In this case, from a rich condition to a 

leaner (albeit still rich) fuel:air equivalence ratio. 

1-1 

1. INTRODUCTION 

1.1 BACKGROUND 

The Energy Independence and Security Act of 2007 calls on the nation to significantly increase 

its use of renewable fuels to meet its transportation energy needs. The law establishes a new 

renewable fuel standard (RFS) that requires the nation to use 36 billion gallons of renewable fuel in 

its vehicles by 2022. Given that ethanol is the most widely used renewable fuel in the United States* 

and production is expected to grow steadily over the next several years, ethanol—both from corn† and 

from cellulosic feedstocks—will likely make up a significant portion of the new renewable fuel 

requirements. The vast majority of ethanol used in the United States is blended with gasoline to create 

E10—that is, gasoline with up to 10% ethanol. The remaining ethanol is sold in the form of E85—a 

gasoline blend with as much as 85% ethanol that can be used only in flexible-fuel vehicles (FFVs). 

Consumption of E85 is currently limited by both the size of the flex-fuel vehicle fleet and the number 

of E85 fueling stations.‡

 While U.S. automakers have committed to significantly ramping up 

production of FFVs, only about 7% of the existing U.S. fleet is replaced each year. That means a 

significant number of the non-FFVs in use today will remain in the vehicle stock for many years to 

come. 

In light of projected growth in ethanol production, as well as the new RFS, most analysts agree 

that the E10 market will be saturated in the next few years, possibly as soon as 2010.§

 Although the 

U.S. Department of Energy (DOE) remains committed to expanding E85 infrastructure, that market 

will not be able to absorb projected volumes of ethanol in the near term. Given this reality, DOE and 

others have begun assessing the viability of using intermediate ethanol blends as one way to 

potentially accommodate growing volumes of ethanol. 

In summer 2007, DOE initiated a test program to assess the potential impacts of intermediate 

ethanol blends on typical vehicles (non-FFVs) as well as on other engines that rely on gasoline. The 

latter include small non-road engines (SNREs) such as those used in lawn and garden equipment and 

engines for marine applications, motorcycles, and snowmobiles. 

The DOE program has been co-led and funded by the DOE Office of Energy Efficiency and 

Renewable Energy (EERE) Biomass Program and the EERE Vehicle Technologies Program with 

technical support from the Oak Ridge National Laboratory (ORNL) and the National Renewable 

Energy Laboratory (NREL). Before designing the test program, DOE tasked ORNL to conduct a 

literature search on the subject, which indicated that insufficient data exists to predict the impacts of 

these fuels on U.S. vehicles and engines.** 

DOE’s test program focuses specifically on the effects of E15 and E20—gasoline blended with 

15% and 20% ethanol—but considers both E0 (gasoline) and E10 as baseline fuels. Through a wide 

range of experimental activities, DOE is evaluating the effects of these intermediate ethanol blends on 

a variety of potentially affected equipment. Some of these activities are being co-funded and managed 

by other entities, including the Coordinating Research Council (CRC) and the U.S. Environmental 

Protection Agency (EPA). 

 *

In 2007, the United States produced more than 6.5 billion gallons of ethanol and imported another 450 million gallons. 

†

The law puts a 15-billion-gallon limit on credits available for the amount of corn ethanol that can contribute to the 

renewable fuel standard. 

‡

Less than 1% of the ethanol used in the United States today is sold in the form of E85. Approximately 7 million flexfuel vehicles, or about 3% of the U.S. fleet, are in use today with less than 1% of U.S. fueling stations providing E85. 

§

At this time, less than 50% of gasoline is blended with 10% ethanol due to blending infrastructure limitations, some 

state specifications, and other factors. If these limits are removed, the E10 market could be saturated once ethanol levels 

reach about 14 billion gallons. **R. Bechtold, J. F. Thomas, S. P. Huff, J. P. Szybist, T. J. Theiss, B. H. West, M. Goodman, T. A. Timbario, 

“Technical Issues Associated with the Use of Intermediate Ethanol Blends (>E10) in the U.S. Legacy Fleet,” ORNL/ 

TM-2007/37, August 2007. 
1-2 

For example, DOE is evaluating the impact of intermediate ethanol blends on tailpipe emissions 

over the full useful life of a wide range of high-sales-volume vehicles. DOE is also funding studies 

that evaluate the effects of intermediate blends on driveability as well as materials used in vehicles 

and infrastructure components. Current and additional projects are continually being evaluated and 

modified as appropriate or as needed based on funding availability. Additional details are contained in 

Section 4 of this report. 

This first report provides results from the first stages of a much larger overall test program. 

Results from additional projects that are currently underway or in the planning stages are not included 

in this first report. The purpose of this initial study was to quickly investigate the effects of adding up 

to 20% ethanol to gasoline on the following. 

• Regulated tailpipe emissions for 16 popular late model vehicles on a drive cycle similar to real-

-world driving and 28 SNREs under certification or typical in-use conditions. *

• Exhaust and catalyst temperatures of the same vehicles under more severe conditions. 

• Temperature of key engine components of the same SNREs under certification or typical in-use 

conditions. 

• Observable operational issues with either the vehicles or SNREs during the course of testing. 

(Studies focused on operational issues, including safety aspects of personal and recreational 

engines, are viewed as important but are beyond the scope of this first report.) 

1.2 TEST PROGRAM OVERVIEW 

The DOE team (DOE, NREL, and ORNL) collaborated with industry and other experts regarding 

the development and implementation of the test program. A number of automotive and non-road 

engine manufacturers provided significant input to the test protocols. This collaboration was typically 

coordinated through industry organizations such as the U.S. Council for Automotive Research, the 

CRC, the Outdoor Power Equipment Institute, the Alliance of Automobile Manufacturers, the 

Association of International Automobile Manufacturers, and the National Marine Manufacturers 

Association. Staff at EPA provided important guidance for test design and sample vehicle and small 

engine selection based on sales volumes and related test programs. In addition, statistical experts at 

Battelle Memorial Institute assisted in the vehicle selection process and data analysis. Argonne 

National Laboratory (ANL) also assisted in data collection. DOE expects to continue to work closely 

with industry, EPA, and others on ongoing and future tests. 

Close interactions with representatives from the affected industries as well as EPA have been 

particularly helpful in refining or developing test protocols to assess the impact of intermediate 

ethanol blends on the equipment being tested. With respect to the specific studies presented in this 

report, standard test procedures were used where possible; however, in many cases, test protocols had 

to be modified or created where they did not yet exist. 

In the interest of gathering data as quickly, accurately, and efficiently as possible, DOE is 

working with industry and EPA to leverage parallel and related studies where possible. In some cases, 

DOE is funding studies jointly with industry; however, in all instances, independent laboratories 

conduct the tests and provide raw data. These efforts include, but are not limited to, the following. 

• DOE is providing technical input, reviewing data, and monitoring the progress of intermediate 

blends testing underway at other organizations [e.g., Rochester Institute of Technology (RIT), 

State of Minnesota, Renewable Fuels Association (RFA)]. The Minnesota/RFA E20 studies 

include a project to assess the materials compatibility of E20 on typical fuel system materials. In 

the case of RIT, test protocols have been harmonized to potentially allow a combined analysis of 

this dataset with DOE’s dataset once testing is completed. 

 *

Ten different equipment models were tested, with multiple copies tested in some cases for a total of 28 engines. 
1-3 

• Four of the vehicle test projects are being conducted in partnership with CRC, a research 

organization established and funded by the automotive and petroleum industry. These studies are 

jointly funded by DOE and CRC. 

This report provides results available to date from the first stages of the overall test program. 

Emissions and temperature data, as well as operational observations, from testing 16 vehicles and 

28 SNREs are summarized. 

Section 2 (Experimental Setup) provides detailed information concerning the protocols and 

procedures used to conduct the studies presented in this report. Section 3 (Results and Discussion) 

summarizes the vehicle and SNRE studies and presents data from testing completed to date. Section 4 

(Next Steps) describes planned future work. The appendixes provide test procedure details, vehicle 

and SNRE emissions standards, analysis details, and additional data and tables from vehicle and 

SNRE tests. 
2-1 

2. EXPERIMENTAL SETUP 

The DOE team used existing test protocols where available and developed test plans where 

needed to evaluate E0, E10, E15, and E20 on vehicles and SNREs. In some cases, the DOE team 

adjusted test procedures based on the manufacturer’s input. The specific procedures for all tests are 

outlined in this section. 

2.1 TEST FUELS AND ANALYSIS 

Four fuels of varying ethanol blend level were included in this program to determine each 

vehicle’s or small engine’s response to intermediate ethanol blend concentrations. Ethanol blend 

concentration levels were specified on a volume-percent basis and included 0%, 10%, 15%, and 20% 

(E0, E10, E15, and E20). E0 and E10 were both included as they represent legal fuels for sale in the 

United States. 

All fuels were splash blends of E0 (certification gasoline, i.e., Indolene) with fuel-grade ethanol 

(per ASTM D4806) supplied by Gage Products Company. Splash blends were used for expediency in 

this pilot study due to the long iterative development process required to obtain match-blended fuels. 

The main differences in fuel chemistry between splash-blended and match-blended fuels are expected 

to be vapor pressure and hydrocarbon profile, neither of which is expected to have a significant effect 

on the major findings of this study. This assertion will be validated by other activities within the DOE 

test program, which will use match-blended fuels. 

Fuels were analyzed by the Fuel Analysis Laboratory at Southwest Research Institute. Table 2.1 

summarizes the analyses performed and methods used. 

A summary of selected fuel properties for fuel samples taken from each of the test laboratories is 

included in Table 2.2. Fuels labeled as ANL and ORNL were used for ANL-specific and ORNLspecific vehicle testing at the Transportation Research Center (TRC). ORNL fuels were also supplied 

directly to the ORNL laboratory for in-house vehicle and small engine testing. NREL fuels were used 

for all vehicle tests at the Colorado Department of Public Health and Environment (CDPHE) test site. 

Table 2.1. Test fuel property measurements

Property ASTM 

specification Description 

Volume percent 

ethanol and oxygen 

weight fraction 

D5599 Standard test method for determination of oxygenates in 

gasoline by gas chromatography and oxygen selective 

flame ionization detection 

Dry vapor pressure D5191 Standard test method for vapor pressure of petroleum 

products (mini method) 

Lower heating value D240 Standard test method for heat of combustion of liquid 

hydrocarbon fuels by bomb calorimeter 

Specific gravity D4052 Standard test method for density and relative density of 

liquids by digital density meter 

Carbon/hydrogen 

weight fraction 

D5291 Standard test method for instrumental determination of 

carbon, hydrogen, and nitrogen in petroleum products and 

lubricants 
2-2 

Table 2.2. Test fuel properties 

Test 

laboratory Fuel EtOH (vol %) 

DVPE 

(psi) 

LHV 

(Btu/lbm) SG C (wt frac) 

H 

(wt frac) 

O 

(wt frac) 

E0 0.0 8.96 18,533 0.746 0.8615 0.1305 0.0000 

E10 9.9 9.81 17,873 0.750 0.8184 0.1237 0.0365 

E15 13.9 9.63 17,471 0.752 0.8072 0.1268 0.0511 

NREL 

E20 18.6 9.65 17,091 0.754 0.7877 0.1292 0.0679 

E0 0.0 8.40 18,534 0.746 0.8683 0.1297 0.0000 

E10 9.1 9.48 17,844 0.750 0.8256 0.1262 0.0336 

E15 14.4 9.33 17,485 0.752 0.8016 0.1252 0.0527 

ORNL 

E20 19.8 9.23 17,043 0.755 0.7966 0.1284 0.0723 

E0 0.0 8.49 18,542 0.746 0.8683 0.1285 0.0000 

E10 9.9 9.34 17,793 0.751 0.8229 0.1285 0.0362 

E15 14.3 9.39 17,412 0.752 0.8058 0.1341 0.0524 

ANL 

E20 19.6 9.15 17,044 0.755 0.7897 0.1271 0.0717 

Abbreviations: EtOH = ethanol; DVPE = dry vapor pressure equivalent; LHV = lower heating value; SG = specific 

gravity; C = carbon; H = hydrogen; O = oxygen. 

2.2 VEHICLES 

2.2.1 Experimental Parameters 

The main factors in the experimental setup for this study were 

• fuel type, 

• vehicle type, and 

• test cycle. 

Vehicles were selected based on manufacturer and engine configuration (cylinders and 

displacement, etc). Fuels were chosen to include both currently legal and potential intermediate 

ethanol blends. Each vehicle was tested using four fuels of varying ethanol blend level. Emissions 

were determined using the LA92 drive cycle, also known as the unified cycle.*

 The LA92 was chosen 

for all emissions testing based on consultation with EPA and the fact that it is being used in the 

EPAct program. This cycle is considered representative of real-world emission changes as it more 

accurately represents typical acceleration rates and speeds of actual drivers on the road than does the 

Federal Test Procedure (used for emissions certification testing). Details on test and measurement 

hardware and test procedures are provided in Appendix A, as well as emissions standards relevant to 

the vehicles tested. 

2.2.1.1 Vehicle selection 

A database of registered vehicles was purchased from R. L. Polk & Co. to characterize the 

population of light-duty vehicles in the U.S. fleet during 2007. Table 2.3 shows the number of 

 *

http://www.arb.ca.gov/msei/onroad/briefs/Publication3.pdf 
2-3 

Table 2.3. Number of registered gasoline-powered vehiclesa in the United States 

on January 1, 2007—by model year period, manufacturer, and 

number of cylinders (vehicle numbers are in thousands) 

Model year Number of cylinders 

period Manufacturer 

4 6 8 Other 

Total 

Pre-1996 

(Tier 0 and 

older) 

All 25,948 34,597 16,512 1,573 78,630 

Chrysler 1,338 3,943 1,584 45 6,910 

Ford 1,894 5,100 4,021 100 11,116 

GM 3,421 7,090 3,851 44 14,406 

Honda 2,581 540 – 35 3,157 

Nissan 1,146 914 28 0 2,088 

Toyota 2,492 1,438 130 1 4,061 

Volkswagen 542 188 6 0 737 

Other 2,228 1,206 294 278 4,006 

1996–1999 

(Tier 1) 

Subtotal 15,642 20,420 9,915 504 46,481 

Chrysler 1,788 4,191 2,445 25 8,449 

Ford 1,586 5,603 5,300 256 12,744 

GM 3,474 9,894 5,996 88 19,452 

Honda 3,671 2,154 – 0 5,825 

Nissan 1,293 2,045 163 0 3,501 

Toyota 3,778 3,174 1,001 – 7,953 

Volkswagen 1,309 474 55 0 1,838 

Other 4,466 4,139 784 447 9,836 

2000–2004 

(Tier 2 

Transitional) 

Subtotal 21,366 31,673 15,743 816 69,598 

Chrysler 767 2,528 1,071 8 4,373 

Ford 715 2,095 1,934 43 4,786 

GM 1,652 3,589 2,265 273 7,779 

Honda 1,752 1,273 – – 3,025 

Nissan 872 1,088 238 – 2,199 

Toyota 2,457 1,935 499 – 4,892 

Volkswagen 288 91 41 181 601 

Other 1,956 2,000 425 278 4,659 

2005–2007 

(Tier 2) 

Subtotal 10,458 14,599 6,474 782 32,313 

Grand total 73,414 101,289 48,645 3,675 227,022 

a

Does not include flexible-fuel vehicles. 

gasoline-powered (non-FFV) registered vehicles by model year period, manufacturer, fuel type, and 

number of cylinders. The total population includes all vehicle manufacturers; however, subtotals are 

presented only for the top seven vehicle manufacturers. The Polk database also provided details such 

as vehicle make and model, engine displacement, fuel type, and transmission type. 

Model year periods were generally defined to correspond to different regulatory periods. For the 

purposes of this study, vehicles were categorized by model year into four basic emission level groups, 

as follows. 

• Tier 0, Pre-1996: Tier 0 gaseous emissions standards were in force from 1981 through 1993 

(although not denoted Tier 0 until 1987). These standards were phased out from 1994 through 

1996. 
2-4 

• Tier 1, 1996 through 1999: Tier 1 emissions standards were phased in from 1994 through 1996 

with full compliance required in 1996. 

• Tier 2 Transitional, 2000 through 2004: The National Low Emission Vehicle program began 

transition to Tier 2 emissions levels from 2000 through 2004. 

• Tier 2, 2004 through 2007: Tier 2 emissions standards were phased in for light-duty passenger car 

vehicles beginning in 2004, with full compliance required in 2007. 

Vehicles were selected to meet several analysis objectives. Of the initial 11 vehicles, three pairs 

were selected to represent a range of engine sizes and manufacturers, with each pair consisting of a 

2003 and a 2007 vehicle from the same manufacturer and similar engine configuration. The vehicle 

pairs were chosen to evaluate the effect of ethanol during the progression in emissions control 

technology from transitional Tier 2 to full Tier 2 compliance. 

• 2003 and 2007 Toyota Camry 2.4L I4 

• 2003 and 2007 GM LeSabre/Lucerne 3.8L V6 

• 2003 and 2007 Ford F150 5.4L V8 

Five additional vehicles were selected based on sales volume data; however, some consideration 

was also given to vehicles that complemented those selected for EPA’s EPAct (Energy Policy Act) 

study, which involved a similar test protocol. 

• 2003 Ford Taurus 3.0L V6 

• 2003 Nissan Altima 3.5L V6 

• 2007 Honda Accord 2.4L I4 

• 2007 Chrysler Town & Country 3.3L V6 

• 2007 GM Silverado 4.8L V8 

Following this initial selection of 11 vehicles (Phase A), a second set of vehicles was selected 

(Phase B). These vehicles were selected using information from auto manufacturers concerning 

specific models that were most likely to be sensitive to increased ethanol content in gasoline,*

 while 

also considering sales volumes. 

• 1999 Honda Civic 

• 2004 VW Golf GTI 

• 1999 Ford Crown Victoria 

• 1999 Toyota Corolla 

• 2001 Chrysler PT Cruiser 

A summary of all vehicles selected for testing is included in Table 2.4. This table contains 

information about each vehicle, including odometer reading, engine family, and applicable emissions 

standard. 

Results presented in this report are based on results for the 11 vehicles selected in Phase A as well 

as all five of the Phase B vehicles. Although these 16 vehicles were not selected “at random,” with 

the exception of the three 1999 model year vehicles they are generally representative of the 

population of late model gasoline-powered vehicles (model year 2000 to 2007) that were on the road 

in early 2007. In particular, the number of vehicles tested was nearly proportional to the population 

counts for each manufacturer, engine size category (number of cylinders), and emissions standard 

period (Transitional Tier 2: 2000 through 2004 or Tier 2: 2005 through 2007). 

 *

The CRC Emissions Committee identified several vehicles suspected of not applying long-term fuel trim under 

high-load, open-loop conditions (http://www.crcao.com/doingbusiness/recentRFP.html, CRC Project No. E-87-1). 
Table 2.4. Test vehicle list 

OEM 

(make) Model Year Engine 

Initial 

odometer 

reading 

(miles) 

EPA engine 

family 

Emission 

standard T

Chrysler Town & Country 2007 3.3 L V6 35,000 7CRXT03.8NEO Tier 2, Bin 5 NRELFord F150 2007 5.4 L V8 28,600 7FMXT05.44H7 Tier 2, Bin 8 TRC Ford F150 2003 5.4 L V8 57,000 3MFXT05.4PFB Tier 1 LEV TRC Ford Taurus 2003 3.0 L V6 89,600 3FMXV03.0VF3 Tier 2, Bin 8 TRC GM (Buick) Lucerne 2007 3.8 L V6 10,000 7GMXV03.9146 Tier 2, Bin 5 

(CA LEV II) 

NREL

and 

GM (Buick) LeSabre 2003 3.8 L V6 78,000 3GMXV03.8044 Tier 2, Bin 8 NRELGM Silverado 2007 4.8 L V8 12,800 7GMXT05.3379 Tier 2, Bin 8 TRC Honda Accord 2007 2.4 L I4 11,400 7HNXV02.4KKC Tier 2, Bin 5 

(CA LEV II) 

TRC 

Nissan Altima 2003 3.5 L V6 53,300 3NSXV03.5C7A LEV TRC Toyota Camry 2007 2.4 L I4 26,440 7TYXV02.4BEB Tier 2, Bin 5 ORN

NRE

Toyota Camry 2003 2.4 L I4 72,800 3TYXV02.4HHA ULEV ORNChrysler PT Cruiser 2001 2.4 L I4 93,400 1CRXV02.4VD0 NLEV NRELFord Crown Victoria 1999 4.6 L V8 50,900 XFMXV04.6VBE ULEV NRELHonda Civic 1999 1.6 L I4 79,680 XHNXV01.6TA3 Tier 1 ORNToyota Corolla 1999 1.8 L I4 96,400 XTYXV01.8XBA Tier 1 NRELVW Golf GTI 2004 1.8 L I4 Turbo 32,900 4ADXV01.8356 Tier 2, Bin 8 ORN

aRound-robin vehicle tested at two sites; abbreviations: LEV = low-emissions vehicle, NLEV = National Low Emission Vehicle Program vehicle

emissions vehicle.

2-5 
2-6 

2.2.1.2 Test sites 

Vehicle testing was conducted simultaneously at three separate emissions laboratories to expedite 

the program. 

• ORNL, Knoxville, Tennessee 

• TRC, East Liberty, Ohio 

• CDPHE emissions test laboratory, Aurora, Colorado 

2.2.1.3 Test condition temperature 

Nominal testing temperature for all reported data was 75°F per Code of Federal Regulations 

(CFR) requirements. Testing over a wider temperature range will be necessary to fully evaluate the 

vehicle emissions impacts of intermediate ethanol blends; however, such testing was beyond the 

scope of this pilot program. 

2.2.2 Statistical Analysis 

For this first report, statistical analysis was conducted to address two main objectives. 

1. Determine whether the relative change in emissions when using ethanol in the fuel (E10, E15, or 

E20) versus E0, averaged across all vehicles, is different from zero. 

2. Determine whether the percentage of vehicles that experience an increase in emissions when 

using ethanol fuel versus E0 is different from 50%. 

This approach involved calculating the change in average measured emissions and fuel economy 

(based on triplicate emissions tests) between the fuels containing ethanol (E10, E15, and E20) and E0. 

The relative change for each vehicle was obtained by dividing by the average emissions with E0. The 

null hypothesis assumed for all data was that there is no correlation between the ethanol content of the 

fuel and emissions or fuel economy results. Thus, the average change in emissions among all vehicles 

should be zero, and the percentage of vehicles with positive changes in emissions should be 50%. 

To address the first objective, a standard t-test was performed to test the hypothesis that the 

average change is zero. For this analysis, the 16 tested vehicles were treated as a random sample from 

the population of late model vehicles (model year 2000 to 2007) in the United States in early 2007. 

Although the vehicles were not selected at random, they are generally representative of the target 

population, as discussed above. The use of a t-test is equivalent to calculating 95% confidence limits 

on the average change in emissions. For example, if the t-test determines that the estimated average 

change in emissions is statistically significant (i.e., different from zero) at the 5% significance level, 

then the 95% confidence bounds on the estimated average would not include the value zero. That is, 

the magnitude of the confidence limit is smaller than the magnitude of the estimated average change. 

The second objective was addressed using the “sign” test to determine whether the frequency of 

positive or negative changes (among the 16 vehicles) was significantly different from 50%. 

According to this procedure, if 13 or more of the changes in emissions among the 16 vehicles have 

the same sign (positive or negative), the finding is statistically significant at the 5% level. 

Significance levels were determined using the binomial probability distribution function. Generally, 

the sign test and the t-test produce similar results. 

This analysis was performed using the various procedures in the Statistical Analysis System 

(SAS) software package. 
2-7 

2.3 SMALL NON-ROAD ENGINES 

2.3.1 Experimental Parameters 

SNREs were examined in two distinct studies: a 6-engine pilot study and a 22-engine full-usefullife (full-life) study. The main factors in the experimental setup for the two studies were 

• fuel type, 

• engine type, 

• emissions test cycles, and 

• aging test cycles. 

2.3.1.1 Engine selection 

SNREs under 25 hp are categorized by EPA according to engine displacement and application. A 

summary of engine classifications is shown in Table 2.5. The highlighted sections of this table 

represent the classifications that have been tested under the first phase of this test program. 

Table 2.5. Small non-road engine classification descriptions per 40 CFR 90a

Full, useful life (hr) 

Class Type Typical 

application 

Displacement 

(cc) Residential 

(moderate use) 

Commercial 

(extended use) 

ISO 8178 

emissions 

test cycleb

I-A <66 50 300 

I-B 66 ≤ disp < 100 125 500 

I 

Non-handheld 

Lawnmower 

small generator 

set 100 ≤ disp < 225 125 500 

G1 or G2 

II Non-handheld Larger equip. 

small tractor ≥225 250 1,000 G1 or G2 

III <20 

IV 20 ≤ disp < 50 

V 

Handheld Line-trimmer 

blower chainsaw 

≥50 

50 300 G3 

a

Highlighted sections indicate the classifications that have been tested under the first phase of this test program. b

Cycles are described in greater detail in Table 2.7.

EPA staff were consulted on engine selection and equipment to ensure that engines selected 

reflected those commonly found in popular, high-sales-volume equipment. 

The laboratories conducting the pilot studies were not equipped with small engine dynamometers, 

so engines that could readily be operated using the installed machine in lieu of a dynamometer were 

preferentially considered for both studies. Aging engines using the installed machine in the full-life 

study allowed aging of all engines in parallel with a realistic, in-use load. 

The pilot study focused on these engine classes/classifications, as detailed in Table 2.6. 

• Class I and II engines—generator sets 

⎯ 1 commercial Class I (500-hr life) 

⎯ 1 field-aged Class I (no full-life hour requirement in 1999) 

⎯ 1 residential Class II (250-hr life) 

⎯ 1 commercial Class II (1,000-hr life) 

• Class IV engines 

⎯ 1 residential blower (50-hr life) 

⎯ 1 commercial line trimmer (300-hr life) 
2-8 

The subcontracted full-life study focused on these four engine classes, as highlighted in 

Table 2.6. 

• Power washer—1 residential Class I (125-hr-life power washer) 

• Generator set—1 commercial Class I (500-hr-life generator) 

• Leaf blower—1 residential Class IV (50-hr-life leaf blower) 

• Line trimmer—1 commercial Class IV (300-hr-life line trimmer) 

The engines selected allowed for full-life testing to be conducted on the equipment rather than on 

the dynamometer, allowing all four engines of a type to be aged in parallel on their respective fuels 

without tying up dynamometer stands. 

2.3.1.2 Emission test cycles 

SNREs are categorized by EPA according to engine displacement and application, which 

determine the required emissions test cycle, as noted in Table 2.5. A summary of emission test cycle 

requirements and weighting factors for computing composite emissions is shown in Table 2.7 and 

described below. 

During G1 and G2 emission tests, the engine is operated in the following manner. 

• Mode Point 1 (Title 40 CFR 90 A-Cycle): Engine operated at intermediate (G1) or rated (G2) 

speed at wide-open throttle (WOT). 

• Mode Points 2–5 (Title 40 CFR 90 A-Cycle): The governor in its production configuration will 

control engine speed at the specified load points. 

• Mode Point 6 (Title 40 CFR 90 A-Cycle): If the engine does not have a user-selectable governor, 

it will be allowed to operate at high idle speed determined by the installed governor. Otherwise, 

the engine will be operated at user-selectable low idle speed. 

During G3 emissions tests, the engine is operated in the following manner. 

• Mode Point 1 (Title 40 CFR 90 C-Cycle): Engine operated at rated speed at WOT. 

• Mode Point 6 (Title 40 CFR 90 C-Cycle): If the engine does not have a user-selectable governor, 

it will be allowed to operate at high idle speed determined by the installed governor. Otherwise, 

the engine will be operated at user-selectable low idle speed. 

These testing procedures were largely followed in both the pilot and full-life studies; however, 

any deviations are noted in the Test Procedures section of Appendix B. Appendix B also contains 

tables showing the Phase 1 and Phase 2 emissions standards applicable to SNREs. 
2-9 

Table 2.6. SNRE equipment tested in pilot and full-useful-life (full-life) studies 

Equipment tested 

(EPA family 

number) 

Class 

(residential/ 

commercial) 

Engine 

size 

(cc) 

Full life 

(hr) 

Included 

full-life 

testing 

Testing 

laboratory New/full life Number of enginesa

Pilot study 

Honda generator 

2HNXS.1961AK

I—Commercial 196 500 No ORNL New 1 

Honda generatorb

(used) 

XHNXS.1631AA

I—N/A 163 NA Yesb

 ORNL Full life 1 

Briggs and Stratton 

generator 

7BSXS.2492HC

II—Residential 249 250 No ORNL New 1 

Kohler generator 

6KHXS.7252GC

II—Commercial 725 

(2-cyl) 

1,000 No ORNL New 1 

Poulan leaf blower 

7PWES.0254BM

IV—Residential 25 50 Yes NREL New 1 

Stihl line trimmer 

6A8XS.0284RA

IV—Commercial 28.4 300 No NREL New 1 

Full-life study 

Briggs & Stratton 

power washer 

6BSXS.1581VG

I—Residential 158 125 Yes TRC Both 6 

Honda generator 

6HNXS.196A5A

I—Commercial 196 500 Yes TRC Both 4 

Weed Eater blower 

7PWES.0254BA

IV—Residential 23 50 Yes TRC Both 8 

Stihl line trimmer 

6A8XS.0314RC

IV—Commercial 31.4 300 Yes TRC Both 4 

a

Where number of engines is greater than four, more than four engines were baselined before commencement of aging 

four engines. b

The used Honda engine at ORNL was field-aged (considered full life given its age) and tested on only E0, E10, and E20. 

Table 2.7. ISO 8178 emission test cycles 

Mode weighting factors from ISO 8178 test cycle 

Test cycle 

1 2 3 4 5 1 2 3 4 5 6 

Torque, % 100 75 50 25 10 100 75 50 25 10 0 

 Rated speed Intermediate speed Low 

idle 

G1 – – – – – 0.90 0.20 0.29 0.30 0.07 0.05 

G2 0.09 0.20 0.29 0.30 0.07 – – – – – 0.05 

G3 0.85 – – – – – – – – – 0.15 
2-10 

2.3.1.3 Test sites 

SNRE testing was conducted at the following laboratories. 

• Pilot study 

⎯ ORNL—Fuels, Engines, and Emissions Research Center, Knoxville, Tennessee 

⎯ NREL—ReFUEL Laboratory, Golden, Colorado*

 

• Full-life study 

⎯ TRC, East Liberty, Ohio 

2.3.1.4 Test condition temperature 

Nominal temperature for emissions testing at all labs was 75°F. Aging was conducted outside at a 

range of ambient temperatures. 

 *

The ReFUEL Laboratory is at 1,700 m (5,700 ft) elevation. 
3-1 

3. RESULTS AND DISCUSSION 

3.1 VEHICLES 

The goals of this study were to assess the effects of using intermediate ethanol blends up to E20 

on the following: 

• emissions and fuel economy, 

• exhaust and catalyst temperature, and 

• informal observations of operation and driveability. 

Sixteen in-use, properly functioning light-duty passenger vehicles were included in this study. The 

objective was to determine the extent to which ethanol in the fuel has an immediate effect on 

regulated emissions, selected aldehyde emissions, and fuel economy for the “average” light-duty 

vehicle. 

A summary of findings is provided below, with additional details in the remainder of this section. 

3.1.1 Emissions and Fuel Economy Summary 

Test results were statistically analyzed to determine whether sufficient evidence existed in the 

data to conclude that ethanol concentrations up to 20% in the fuel changed emissions or fuel 

economy, either when averaged across all vehicles or for a majority of vehicles. Results are presented 

in terms of statistical significance based on a Student’s t-test as described in Sect. 2. “Statistically 

significant” results are those that can be stated with a 95% confidence level or better. “Marginally 

significant” results correspond to a 90% or higher confidence level. 

The following regulated tailpipe emissions showed no discernable trend with increasing ethanol 

content. 

• Oxides of nitrogen (NOX) and non-methane organic gases (NMOG) showed no statistically 

significant trend with fuel type. 

The following trends from E0 to E20 were found to be statistically significant. 

• Carbon monoxide emissions declined with E20 (12% on average) when compared to E0. This 

result was statistically significant, and similar reductions were found with E10 and E15 (15% on 

average for each). 

• Non-methane hydrocarbons (NMHC) decreased with E20 (15% on average) when compared to 

E0. This result was statistically significant, and similar reductions were found with E10 and E15 

(12% and 11% on average, respectively). 

• Fuel economy decreased (7.7% on average), consistent with the energy density reduction 

associated with ethanol blending (in limited tests, this trend was observed to continue to E30). 

• Ethanol emissions increased with E20 from zero by an average 8.2 mg/mi. Increases for E10 and 

E15 were 5.6 mg/mi and 6.8 mg/mi, respectively. 

• Acetaldehyde emissions increased with E20 by an average of 0.81 mg/mi from an average of 

0.35 mg/mi for E0. Increases for E10 and E15 were 0.38 mg/mi and 0.70 mg/mi, respectively. 

• Formaldehyde emissions increased with E20 by an average of 0.11 mg/mi from an average of 

0.71 mg/mi for E0. Increases for E10 and E15 were 0.11 mg/mi and 0.14 mg/mi, respectively. 
3-2 

3.1.2 Exhaust and Catalyst Temperature Effects Summary 

The following observations were made based on measurements of exhaust fuel:air ratio and 

temperatures of the exhaust system and catalyst with E0 and E20. 

• Seven vehicles ran leaner with E20 than with E0 fuel, but still rich, at wide open throttle. The 

change in fuel:air equivalence ratio roughly corresponded to the oxygen content of the fuel. A 

hypothesis about differences in engine control system approach to explain this leaner operation is 

presented in Sect. 3.1.5.1. 

• For vehicles that ran leaner on E20, peak catalyst temperatures were found to increase by 29° to 

35°C during WOT accelerations when compared to operation on E0. 

• For vehicles that did not run leaner on E20, peak catalyst temperatures were slightly cooler on 

average but largely unchanged during WOT accelerations when compared to operation on E0. 

• During closed-loop (stoichiometric) operation, exhaust and catalyst temperatures were slightly 

cooler on average but largely unchanged with increased ethanol content on all vehicles tested. 

3.1.3 Unforeseen Operational Issues Summary 

• No driveability or operability issues were observed for the 16 vehicles tested in this pilot study. 

• Although malfunction indicator lights (MILs) did illuminate on two of the vehicles, in no cases 

did MILs appear to illuminate as a result of the ethanol content of the fuel.*

3.1.4 Results and Discussion: Emissions and Fuel Economy 

This section presents a summary and statistical analysis of the emissions and fuel economy data 

obtained from the 16 vehicles tested. Results presented address two statistical analysis objectives. 

1. Determine whether the relative change in emissions when using ethanol in the fuel (E10, E15, or 

E20) versus E0, averaged across all vehicles, is different from zero. 

2. Determine whether the percentage of vehicles that experience an increase in emissions when 

using ethanol fuel versus E0 is different from 50%. 

For this analysis, the vehicles were treated as being selected at random from the population of late 

model vehicles (model years 2000 to 2007) that were on the road in early 2007. Although the tested 

vehicles were not selected at random, they are representative of this population in that the numbers of 

tested vehicles are nearly proportional to the population counts for each manufacturer, engine size 

category (number of cylinders), and emissions standard period (Transitional Tier 2: 2000 through 

2004 or Tier 2: 2005 through 2007). 

Table 3.1 shows the average changes in regulated emissions, fuel economy, and selected aldehyde 

emissions with E10, E15, and E20, relative to E0. Results are presented for fuel economy as well as 

the regulated emissions [non-methane organic gas (NMOG), CO, NOX, and formaldehyde] and 

NMHC, ethanol, and acetaldehyde, which constitute the majority of NMOG emissions. The average 

relative changes were obtained by determining the relative change (from E0 to E20, for example) in 

average emissions measurements for each vehicle, then calculating the average and confidence limits 

using the data from all 16 test vehicles. Changes in ethanol, acetaldehyde, and formaldehyde 

emissions are presented in milligrams per mile, while other emissions changes are presented as 

percent change relative to E0. Results are shown graphically in Figs. 3.1 through 3.4. Bars in Figs. 3.1 

and 3.2 show the average change in emissions with ethanol content considering all vehicles in 

aggregate, while the individual data points show the change for individual vehicles, illustrating the 

 *

The detailed results on operational issues at the end of this section provides specific information on when malfunction 

indicator lights were observed and the presumed causes for the MIL illuminations. 
3-3 

variability in emissions and fuel economy among the vehicles tested. Figure 3.3 shows the actual 

aggregate emissions in g/mi and fuel economy in mpg, and Fig. 3.4 shows the ethanol, acetaldehyde, 

and formaldehyde emissions in mg/mi. Again, the bars show the average across all vehicles and each 

individual point represents a single vehicle average. Results for each individual vehicle plotted 

separately are provided in Appendix C. 

Table 3.1. Estimated change (% or mg/mi) in emissions and fuel economy 

relative to E0 with ±95% confidence limit 

Emission 

(unit of change) E10 E15 E20 

NMOG (%) -2.32 ± 8.96 1.35 ± 12.07 -0.12 ± 11.58 

NMHC (%) -12.04 ± 7.63 a -11.49 ± 9.62 a -15.13 ± 9.04 a

CO (%) -14.98 ± 8.31 a -15.11 ± 10.38 a -12.31 ± 11.96 a

NOX (%) -5.48 ± 16.85 -0.61 ± 18.38 12.23 ± 16.69 

Fuel economy (%) -3.68 ± 0.44 a -5.34 ± 0.53 a -7.71 ± 0.88 a

Ethanol (mg/mi) 5.55 ± 0.23 a 6.85 ± 0.16 a 8.21 ± 0.23 a

Acetaldehyde (mg/mi) 0.38 ± 0.20 a 0.70 ± 0.44 a 0.81 ± 0.45 a

Formaldehyde (mg/mi) 0.11 ± 0.08 a 0.14 ± 0.13 a 0.11 ± 0.10 a

a

Statistically significant at the 95% confidence level (shaded). 

The 95% confidence limits shown in Table 3.1 characterize the statistical uncertainty in the 

average changes. If the magnitude of the confidence limit is greater than the absolute value of the 

relative or absolute change, there is no statistical evidence (at the 95% confidence level) that the 

percent change is different from zero. All estimated changes for NMHC, CO, fuel economy, ethanol, 

acetaldehyde, and formaldehyde were significantly different from zero at the 95% confidence level. 

Changes in fuel economy were consistent based on fuel type and the change in energy density of 

the ethanol blends—approximately a 3.5% decrease in energy for every 10% of ethanol in the fuel. 

There is no statistical evidence that NMOG or NOX emissions were affected by ethanol content. 

An alternative method of calculating the change in emissions from E0 to E20 based on a 

regression of emissions versus the ethanol content of the fuel produced very similar results. Changes 

in fuel economy and emissions of NMHC, CO, ethanol, and acetaldehyde from E0 to E20 were found 

to be statistically significant at the 95% confidence level. 

Table 3.2 presents results of an alternative approach to establishing statistical significance of the 

changes in emissions. Each column shows the number of cases (out of 16 vehicles) for which the 

change in average emissions (from E0 to the indicated fuel) was positive. If the number of positive 

changes is greater than 13 or less than 3, we can conclude at the 95% confidence level that the 

population percentage is different from 50%—indicating there is either a positive or negative effect of 

ethanol. The results for fuel economy, ethanol, and acetaldehyde are consistent with the average 

changes observed in Table 3.1. That is, almost all vehicles realized a decrease in fuel economy and 

increases in ethanol and acetaldehyde emissions. Although the percentages of increases in NMHC 

and CO were consistently less than 50%, suggesting a reduction in emissions, the statistical evidence 

based on this methodology is not conclusive. 
3-4 

Fig. 3.1. Average percentage change in emissions and fuel economy for all vehicles compared to E0 

fuel on the LA92 cycle. Bars show average for all vehicles, while discrete data points show the change for 

each vehicle tested. 

Fig. 3.2. Average change in ethanol and aldehyde emissions for all vehicles compared to E0 fuel 

on the LA92 cycle. Bars show average for all vehicles, while discrete data points show the change for 

each vehicle tested. 

-100

-50

0

50

100

E10 E15 E20 E10 E15 E20 E10 E15 E20 E10 E15 E20 E10 E15 E20

NMOG NMHC CO NOX Fuel

Economy

Percent Change Relative to E0

-100

-50

0

50

100

Indicates last three 

vehicles tested

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

E10 E15 E20 E10 E15 E20 E10 E15 E20

Ethanol ( /10) Acetaldehyde Formaldehyde

Emissions Change Relative to E0 (mg/mi)

-0.5

0

0.5

1

1.5

2

2.5

3

3.5

4

Indicates last three 

vehicles tested
3-5 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

NMOG NMHC CO / 10 NOx FE / 100

Emissions or Fuel Economy (g/mile or mpg)

Indicates last three 

vehicles tested

Fig. 3.3. Average emissions and fuel economy for all vehicles on LA92 cycle. Bars show average 

for all vehicles, while discrete data points show each individual vehicle average. 

0.0

1.0

2.0

3.0

4.0

5.0

6.0

E0 E10 E15 E20 E0 E10 E15 E20 E0 E10 E15 E20

Ethanol ( /10) Acetaldehyde Formaldehyde

Ethanol or Aldehyde Emissions (mg/mile)

Indicates last three 

vehicles tested

Fig. 3.4. Ethanol and aldehyde emissions for all vehicles on LA92 cycle. Bars show average 

for all vehicles, while discrete data points show each individual vehicle average. 
3-6 

Table 3.2. Number of vehicles with positive changes in emissions 

and fuel economy relative to E0 among 16 test vehicles 

Emission E10 E15 E20 

NMOG 5 7 8 

NMHC 4 b 5 4 b

CO 3 a 4 b 6 

NOX 4 b 5 9 

Fuel economy 0 a 0 a 0 a

Ethanol 16 a 16 a 16 a

Acetaldehyde 15 a 16 a 16 a

Formaldehyde 13 a 11 11 

a

Estimated percent of positive changes (out of 16 vehicles) is 

significantly different from 50% at the 95% confidence level (shaded). 

b

Estimated percent of positive changes (out of 16 vehicles) is 

significantly different from 50% at the 90% confidence level. 

3.1.5 Results and Discussion: Exhaust and Catalyst Temperature 

3.1.5.1 Long-term fuel trim correction strategies 

Per EPA guidelines, each engine manufacturer may use up to 6% enrichment (extra fuel) beyond 

LBT (lean best torque) if necessary to protect engine or emissions control hardware from overheating. 

Such enrichment is typically necessary at high engine load and/or high engine speeds. 

The exhaust gas oxygen (EGO) sensor used on most modern vehicles (post-1970s) is a switching 

type oxygen sensor. This type of sensor can determine whether the engine is running rich or lean but 

provides no indication of how rich or how lean. Consequently, this sensor is only able to actively 

adjust for differences in the fuel:air equivalence ratio from the calibrated value during closed-loop 

stoichiometric operation. It is typical for such fuel correction values to be stored in the Engine 

Control Unit (ECU). Thereafter, the previously stored corrections can be applied whenever the engine 

operates in a similar operating condition. Such stored values used for fuel correction are typically 

referred to as long-term fuel trim. 

During certain operating conditions, such as WOT, the engine control system switches from 

closed-loop stoichiometric operation to a fuel enrichment mode to protect both engine and exhaust 

emission control components. This enrichment mode is typically open-loop, using a fuel enrichment 

strategy programmed into the ECU. 

During the course of testing, 7 of the 16 vehicles tested were observed to run significantly leaner 

at WOT as ethanol content in the fuel increased. Furthermore, it was observed that this increase in 

fuel:air equivalence ratio corresponded roughly, on a percent basis, with the increased oxygen content 

of the fuel. For the balance of vehicles tested (9 of 16), the fuel:air equivalence ratio at WOT 

remained nearly constant as ethanol content in the fuel was increased. The hypothesis is that vehicles 

exhibiting nearly constant fuel:air equivalence ratio during WOT used long-term fuel trim values 

acquired during closed-loop operation—including those due to the oxygen content of the fuel—and 

applied this information to open-loop conditions. It is believed that long-term fuel trim correction was 

not being applied during WOT experiments in the remaining seven vehicles, which ran leaner at 

WOT. When long-term fuel trim is not applied to open-loop operation, leaner operation, though still 

rich, is likely when using ethanol blends of up to E20 compared to E0 fuel during open-loop 

operation. Although application of long-term fuel trim to open-loop operation was generally more 

prevalent for the later model vehicles, two of the 2007 model-year vehicles tested in this program did 

not appear to apply long-term fuel trim to open-loop operation. 
3-7 

It is unclear whether vehicles that did not apply long-term fuel trim during WOT operation did so 

by design or whether inadequate time or operating range was allowed for complete adaptation. In 

follow-on experiments with two of the vehicles found to run leaner with increased ethanol content, 

WOT tests with E20 were repeated after six consecutive standard road cycles (SRCs) operated on 

E20. The SRC is a dynamometer driving schedule developed by EPA for vehicle aging and covers a 

broad portion of the engine operating map. After multiple SRCs, the WOT fueling strategy for these 

two vehicles remained unchanged. 

3.1.5.2 Temperatures at wide-open throttle 

Vehicles that ran leaner during WOT than the E0 baseline experienced higher catalyst 

temperatures as ethanol content increased. The long-term effect of this catalyst temperature increase 

on catalyst durability is not known at the current time and requires further work. 

Figure 3.5 shows the average difference in peak catalyst temperature and the range of this 

difference for the 16 vehicles tested. The right-most series of bars (red) in this figure represents the 

temperature increase for the seven vehicles that ran leaner with increased ethanol content during 

WOT accelerations. This data showed an average increase of between 29°C and 35°C from E0 to E20 

and an average increase of about 20°C from E10 to E20. 

The blue series of bars in Fig. 3.5 shows data for the nine vehicles that appeared to apply longterm fuel trim at WOT. For these vehicles, the average peak catalyst temperature difference was 

essentially unchanged (less than 5°C on average) for E20 compared to E0. The range of temperature 

changes measured for all fuels was between –14°C and 14°C. 

3.1.5.3 Temperature effects in closed-loop at high engine load 

For closed-loop, stoichiometric operation at high engine load, no increase in catalyst temperature 

was observed with increasing ethanol content. This testing was conducted under the same operating 

conditions as the hill climb WOT protocol but at a point just before fuel enrichment engaged. 

Appendix A contains details of the test procedure used for this series of tests. 

3.1.5.4 Altitude effects 

Two of the test sites (TRC and ORNL) are located at approximately 1,000 feet above sea level 

and one lab (CDPHE) is sited at an altitude of roughly 5,400 feet. While testing at altitude is 

considered valid for comparing relative fuel effects on catalyst temperature, comparing the WOT 

conditions between test sites at different altitudes is not considered valid. WOT conditions at higher 

altitude will result in reduced mass-air flow due to lower air density. Comparing part throttle results 

from the different test sites is considered valid, since throttling of the intake air should have mitigated 

any significant air density differences. 
3-8 

-20

-10

0

10

20

30

40

50

Average Temperature Change at WOT (°C)

Vehicle DOES apply LFT during power enrichment

Vehicle DOES NOT apply LFT during power enrichment

E10 E15 E20

Range bars indicate maximum and minimum observed 

temperature differences for all vehicles tested.

Fig. 3.5. Change in catalyst temperature versus fuel type for wide-open throttle (WOT) 

open-loop conditions. 

3.1.6 Results and Discussion: Unforeseen Operational Issues 

While driveability was not a focus of this study, no driveability issues associated with ethanol 

fueling were noted for the duration of testing by either the engineers or emissions test drivers. It 

should be noted, however, that the drivers and engineers were not trained specifically to recognize 

driveability problems. Furthermore, environmental conditions for this test program were limited to 

only 50° and 75°F. Other activities within the DOE test program, summarized in Sect. 1, will evaluate 

ethanol-related driveability issues over a broader range of conditions and with a wider range of 

vehicles. 

While no ethanol fuel-related MILs were observed, a few MIL codes illuminated for other 

apparent reasons. The 2003 Ford Taurus at TRC illuminated its MIL (code P0191, fuel rail pressure 

circuit) during its first fuel change. This MIL occurred while draining the fuel tank through the fuel 

rail using the in-tank fuel pump. This MIL was believed to be related to the low fuel pressure 

experienced during the fuel drain with the ignition key on. The code was reset and did not recur 

throughout the testing program. 

Another MIL, related to the catalyst system monitor but not exclusive to ethanol fuel, occurred on 

the 2003 Toyota Camry at ORNL (code P0420). Throughout the course of testing this vehicle, some 

40 individual tests were run (triplicate LA92 on each fuel, WOT tests on each fuel, and four 

preparatory cycles during each fuel switch). The P0420 code was found to be in a pending mode 

frequently and normally reset on its own. The MIL illuminated four times, including testing on E0, 

and was reset each time. The P0420 code would generally set during the fuel change procedures or 

WOT testing. Emissions tests indicated the vehicle was not a gross emitter. After discussions with 

several peers, it was decided to keep the vehicle in the program. 
3-9 

3.2 SMALL NON-ROAD ENGINES 

SNREs under 25 hp are categorized by EPA according to engine displacement and application, 

which determine the required emissions test cycle. A summary of engine classifications is shown in 

Table 3.3. DOE’s small engine testing to date has focused on engine types that fall within the 

highlighted sections of Table 3.3. 

Table 3.3. SNRE classification descriptions per 40 CFR 90a

Full, useful life (hr) 

Class Type Typical 

application 

Displacement 

(cc) Residential 

(moderate use) 

Commercial 

(extended use) 

ISO 8178 

emissions 

test cycleb

I-A <66 50 300 

I-B 66 ≤ disp. < 100 125 500 

I 

Non-handheld 

Lawn mower 

small gen. 

set 100 ≤ disp. < 225 125 500 

G1 or G2 

II Non-handheld Larger equip. 

small tractor ≥225 250 1,000 G1 or G2 

III <20 

IV 20 ≤ disp. < 50 

V 

Handheld 

Line-trimmer 

blower 

chainsaw 

≥50 

50 300 G3 

a

Highlighted sections indicate the classifications that have been tested under the first phase of this test program. 

b

ISO 8178 test cycles are defined in Sect. 2. 

Given that there may be more than 900 individual emissions-certified SNRE families sold for any 

given model year, DOE’s test program could focus only on a small subset of these engine families. 

DOE consulted with EPA on engine selection to ensure that the engines being tested reflected those 

commonly found in popular, high-sales-volume equipment. 

Small engines such as those in lawn mowers and lawn tractors, generators, line trimmers, 

chainsaws, and other similar equipment are open-loop engines, in that exhaust-sensing feedback is not 

used to control the fueling rate. Open-loop engines are commonly air-cooled and customarily operate 

in the fuel-rich regime to achieve cooler combustion temperatures. With a fixed fueling calibration, as 

ethanol content is increased, the relative combustion stoichiometry changes to a leaner (or less rich) 

equivalence ratio, leading to a higher combustion temperature and hence higher component 

temperatures. Similarly, emissions of HC, NOX, and CO are also related to the combustion 

stoichiometry, so these emissions can also be expected to change. Leaner mixtures can also increase 

idle speed on some engines, creating unexpected engagement of centrifugal clutches on equipment 

such as chainsaws or line trimmers. Finally, various fuel-wetted materials in some small engines may 

not be compatible with all ethanol blends. 

3.2.1 Scope of Study 

In late summer 2007, ORNL and NREL acquired six SNREs for preliminary examination (pilot 

study) while a subcontract for a larger full-life study was initiated at TRC, a commercial testing 

laboratory in East Liberty, Ohio. Table 3.4 shows the specific engines tested at the three sites. 

Tests at ORNL and NREL focused on identifying immediate emissions or operational issues with 

federal certification gasoline (E0) and three splash-blended fuels (E10, E15, and E20) and 

measurements of several key engine temperatures. One copy of each engine was tested on all 

four fuels at ORNL and NREL (with one exception, the field-aged Honda generator was not tested 

on E15). 

The TRC program tested four copies of each engine to full life. All engines were tested on E0 and 

then each engine was tested exclusively on E0, E10, E15, or E20. While TRC also measured 
3-10 

temperatures, its main focus was to assess any operational problems during full-life aging and to 

evaluate how engine operation and emissions change over time with exposure to various levels of 

ethanol. Table 3.4 provides additional details on these tests. 

The tests performed at TRC measured emissions and temperature at various stages of the engines’ 

lives—when new, at half life, and at full life. In this set of tests, four engine models were selected: 

• Briggs and Stratton residential Class I (power washer), 

• Honda commercial-Class I (generator), 

• Weed Eater residential Class IV (leaf blower), and 

• Stihl commercial Class IV (line trimmer). 

Table 3.4. SNRE equipment tested in pilot and full-useful-life (full-life) studies 

Equipment tested 

(EPA family 

number) 

Class residential/ 

commercial 

Engine 

size 

(cc) 

Full life 

(hr) 

Engines 

aged to full

life? 

Testing 

laboratory 

Engine 

condition for 

emissions 

testing 

Number 

of 

enginesa

Pilot study 

Honda generator 

2HNXS.1961AK

I—Commercial 196 500 No ORNL New 1 

Honda generatorb 

(used) 

XHNXS.1631AA

I—N/A 163 NA Nob

 ORNL Full life 1 

Briggs and Stratton 

generator 

7BSXS.2492HC

II—Residential 249 250 No ORNL New 1 

Kohler generator 

6KHXS.7252GC

II—Commercial 725 

(2-cyl)

1,000 No ORNL New 1 

Poulan leaf blower 

7PWES.0254BM

IV—Residential 25 50 Yes NREL New 1 

Stihl line trimmer 

6A8XS.0284RA

IV—Commercial 28.4 300 No NREL New 1 

Full-life study 

Briggs & Stratton 

power washer 

6BSXS.1581VG

I—Residential 158 125 Yes TRC New 

Half life 

Full life 

6 

Honda generator 

6HNXS.196A5A

I—Commercial 196 500 Yes TRC New 

Half life 

Full life 

4 

Weed Eater blower 

7PWES.0254BA

IV—Residential 23 50 Yes TRC New 

Half life 

Full life 

8 

Stihl line trimmer 

6A8XS.0314RC

IV—Commercial 31.4 300 Yes TRC New 

Half life 

Full life 

4 

a

Where the number of engines is greater than four, more than four engines were baselined before commencement of aging 

four engines. b

The used Honda engine at ORNL was field-aged (considered full life given its age) and tested on only E0, E10, and E20. The 

engine was not aged in this test program. 
3-11 

TRC initially tested six power washers and eight leaf blowers on E0. For each residential engine 

model type, four engines were selected and randomly assigned to one of the fuel types (E0, E10, E15, 

or E20) for testing. Once an engine was introduced to its specific ethanol blend, it was not exposed to 

E0 again until the full-life emissions tests. 

The purpose of “down-selecting” engines from a larger group was to help ensure that the engines 

tested were fairly consistent with each other to elucidate fuel effects that might otherwise be obscured 

by engine-to-engine scatter. As discussed below and illustrated by the data, the engine tests confirmed 

that emissions and temperature can vary considerably from engine-to-engine, even among engines 

with the same model number, and even on E0. This engine-to-engine scatter appeared particularly 

pronounced with the residential-grade engines. Only four of each of the commercial engines was 

tested initially on E0, and engine-to-engine scatter was deemed not as problematic. 

The testing protocols used at ORNL, NREL, and TRC are described in full in Appendix B. When 

feasible, emissions test methods were consistent with EPA guidelines, although in several cases 

reasonable surrogates were used. Class I and II engines were emissions-tested on the 6-mode cycle, 

and Class IV engines were tested on the 2-mode cycle. Engines were aged using their respective 

emissions testing protocol in most cases. The Class I power washer engines were emissions-tested on 

two different 6-mode cycles, but aged using a 2-mode cycle similar to their use in the field. 

3.2.2 Summary of Results 

Open-loop engines tested in this study exhibited the following trends in emissions and 

temperatures with varying levels of ethanol. 

• As ethanol levels increased, leaner engine operation was observed in all of the tested engines, as 

indicated by decreased CO emissions.*

• Temperatures of both the exhaust and engine components increased as ethanol levels increased. 

• HC emissions generally decreased with increasing ethanol, although increases in HC emissions 

occurred in some engines. 

• NOX emissions increased with higher levels of ethanol in all engines; however, combined NOX + 

HC emissions (which are regulated as such) were tempered by decreasing HC emissions in most 

cases. Net changes of HC + NOX with increasing ethanol ranged from –36% to +41% and were 

engine-specific. 

• CO emissions decreased with higher levels of ethanol. 

• In the case of the 2-cylinder engine tested, temperatures and emissions varied from cylinder to 

cylinder due to differences in the fuel:air distribution between cylinders. Given this observation, 

multicylinder open-loop engines may prove to be more sensitive to ethanol blends than singlecylinder engines. 

• With greater ethanol content, three handheld trimmers demonstrated higher idle speed and 

experienced unintentional clutch engagement. The increased speed was again caused by the 

fuel:air mixture enleanment,†

 which can be adjusted and mitigated in some engines. 

• Residential and Commercial Class I and Class IV engines were aged to full life. The residential 

Class I as well as the commercial engines exhibited no sensitivity to ethanol from a durability 

perspective in the short duration of this project. The effect of ethanol on the durability of the 

residential Class IV engines was not clear given that a number of these engines failed during fulllife aging regardless of fuel type. Failure of these engines may have been related to the engine 

mounting method. 

 *

D’Alleva and Lovell, SAE 360106. 

†

Enleanment means moving toward a leaner fuel:air equivalence ratio—in this case, from a rich condition to a leaner 

(albeit still rich) fuel:air equivalence ratio. 
3-12 

• No materials compatibility issues were observed in the short duration of this project, but they 

were not specifically characterized as part of this study. 

Figure 3.6 shows the average exhaust temperature rise due to ethanol addition for all engines 

tested both when new (e.g., after initial break-in) as well as at full life. Data points indicate the range 

of changes observed at the hottest condition for individual engines. While the aged engines also show 

higher operating temperature with ethanol addition, the increases are not as high as in the new 

engines. Note that not all engines were tested in both the new and full-life conditions, and the 

trendlines shown are for a regression through the simple numerical average of the available data. The 

trends noted are the same when data are parsed out and considered separately by engine class. 

-40

-20

0

20

40

60

80

E10 E15 E20 E10 E15 E20

Exhaust Temperature Increase (°C)

-40

-20

0

20

40

60

80

New Engines Full-life Engines

New Engine Trendline

Full-Life Trendline

-40

-20

0

20

40

60

80

E10 E15 E20 E10 E15 E20

Exhaust Temperature Increase (°C)

-40

-20

0

20

40

60

80

New Engines Full-life Engines

New Engine Trendline

Full-Life Trendline

Fig. 3.6. Exhaust temperature increase for all small non-road engines tested in the new and 

full-useful-life (full-life) condition with ethanol blends, as compared to E0 baseline. Highest 

temperature operation points for each engine are plotted. Trendlines show regression through numerical 

average of all engines. Negative E20 data point for new engines is due to Honda generator running 

erratically on E20 in idle mode. 

Figure 3.7 illustrates the average change in emissions with ethanol addition for all engines tested 

both when new and at full life. Data points represent the change observed in each individual engine. 

HC emissions tend to decrease with increasing ethanol content, although HC emissions actually 

increased in some of the engines in which erratic operation was noted, skewing the trendline for the 

new engines. The Honda generator at TRC ran erratically at light loads in the new condition, 

generating unusually high HC emissions (the highest single E20 point in the top chart in Fig. 3.7). If 

that point is omitted, the general trend shows a decrease in HC with increasing ethanol. For the fulllife data, one of the Briggs and Stratton power washer engines had unusually high HC emissions with 

E10. If this point is omitted, the full-life HC emissions show a very slight decrease with increasing 

ethanol. HC emissions here are as indicated by the flame ionization detector (FID), and do not include 

any correction for oxygenated compounds in the exhaust such as ethanol or aldehydes. CO emissions 

decreased and NOX emissions increased with increasing ethanol content for all engines tested in the 

new condition. The general trends for the full-life data are the same as noted for the engines in the 

new condition, with the exception that NOX decreased for one engine type with E20 fuel. Not all 

engines were tested in both the new and full-life conditions, and the trendlines shown are for a 
3-13 

regression through the simple numerical average of the available data. These same data were also 

parsed by engine class, and the trends noted were largely the same. 

More detailed results and discussion follow, and additional figures and tables for the individual 

engines are provided in Appendix D. 

-100%

-50%

0%

50%

100%

150%

200%

400%

E10 E15 E20 E10 E15 E20 E10 E15 E20 E10 E15 E20

HC NOx HC+NOx CO

New Engines

-100%

-50%

0%

50%

100%

150%

200%

250%

E10 E15 E20 E10 E15 E20 E10 E15 E20 E10 E15 E20

HC NOx HC+NOx CO

Engines at

Full-Life

Average Change in Emissions (%) Average Change in Emissions (%)

-100%

-50%

0%

50%

100%

150%

200%

400%

E10 E15 E20 E10 E15 E20 E10 E15 E20 E10 E15 E20

HC NOx HC+NOx CO

New Engines

-100%

-50%

0%

50%

100%

150%

200%

250%

E10 E15 E20 E10 E15 E20 E10 E15 E20 E10 E15 E20

HC NOx HC+NOx CO

Engines at

Full-Life

Average Change in Emissions (%) Average Change in Emissions (%)

Fig. 3.7. Average change in emissions for all small non-road engines tested in the new (top 

chart) and full-useful-life (full-life) (bottom chart) condition with ethanol blends, as compared to 

E0 baseline. Data points are the numerical average of multiple composite test results for each fuel 

compared to the E0 baseline for the same engine at the same age condition. Trendlines show linear 

regression through numerical average of all data shown for each emissions constituent. Trendlines for 

HC emissions are heavily influenced by two outlier points (see report text for more detail).
3-14 

Table 3.5. Summary of engine operational problems at ORNL, NREL, and TRC 

Equipment tested 

(EPA family number 

Model Year) 

Operational issues noted—

which fuel(s) 

Test 

site Nature of noted operational issue 

Pilot study (ORNL and NREL) 

Honda generator 

2HNXS.1961AK 

2002

No NA ORNL NA 

Honda generator (used)a

XHNXS.1631AA 

1999

No NA ORNL NA 

Briggs and Stratton 

generator 

7BSXS.2492HC 

2007

Yes E20 ORNL Engine stalled twice on E20 fuel. Cause 

unknown 

Kohler generator 

6KHXS.7252GC 

2006

No NA ORNL NA 

Poulan leaf blower 

7PWES.0254BM 

2007

Yes E15 

E20 

NREL Erratic operation on E15 and E20, near fulluseful-life (full-life) hours 

Stihl line trimmer 

6A8XS.0284RA 

2006

Yes E15 

E20 

NREL High idle with E15 and E20 caused clutch 

engagement at idle 

Full-life study (TRC) 

Briggs & Stratton 

power washer 

6BSXS.1581VG 

2006

Yes E10 (PW5) TRC PW5 was baselined on E0 on both TRC and 

BASCOb protocols, then failed during E10 

BASCO testing 

Honda generator 

6HNXS.196A5A 

2006

Yes E20 (G4) TRC Initial E20 test had high HC emissions due to 

erratic operation at light loads (unstable 

governor). Problem did not recur at half life or 

full life 

Weed Eater blower 

7PWES.0254BA 

2007

Yes E0 (B2) 

E15 (B7) 

E15 (B3) 

E20 (B8) 

E20 (B4) 

TRC E0 engine(B2) failed at 41:30 

E15 engine (B7) failed at 25 hr 

2nd E15 engine (B3) failed at 21:47 

E20 engine (B8) would not idle, replaced by B6

B4 would not make full power on E20 

Stihl line trimmer 

6A8XS.0314RC 

2006

Yes E15 (T3) 

E20 (T4) 

TRC High idle speed with E15 and E20 caused 

clutch engagement at idle. Correctable via 

carburetor adjustment 

a

Field-aged Honda generator considered full-life engine. 

b

BASCO refers to Briggs and Stratton Company (BASCO) emissions testing protocol. See Appendix B. 

ORNL = Oak Ridge National Laboratory, NREL = National Renewable Energy Laboratory, TRC = Transportation Research 

Center 
3-15 

3.2.3 Results and Discussion: Engine Operation 

One objective of the SNRE studies was to assess engine operation with the various ethanol blends 

through operator observations during emissions testing or aging. A few engine operation problems 

were noted during the program and will be discussed here. Table 3.5 highlights which engines 

experienced operational problems. A brief discussion for each engine for which an occurrence is 

noted is provided below. 

Briggs and Stratton 3500W generator (pilot study). The Briggs and Stratton generator ran 

normally on E0 but began losing power on E20 at full load. The off-board fuel tanks used for 

gravimetric fuel consumption measurement were set to the same elevation as the factory tank in this 

testing because the engine uses a gravity-feed carburetor. When the engine began to stall on E20, the 

operators elevated the tank several inches and found the engine would run normally. Emissions tests 

on E20 were completed with the tank in the elevated position. After emissions testing, the tank was 

returned to its normal level to see whether the problem would recur, but the engine appeared to run 

normally. Tests with E15, E10, and an E0 repeat were without incident; however, when fueling with 

E20 a second time, the engine stopped abruptly. The engine was restarted and ran normally for the 

duration of the E20 test. 

The operational problem observed on E20 could not be replicated enough times to definitively 

determine a cause. However, two working hypotheses have been developed. Some elastomers and 

plastics are known to swell with ethanol exposure, and the carburetor on this engine uses a plastic 

float and an elastomeric seat for the needle in the carburetor bowl. The seat is only 5 mm across with 

a 1.5-mm hole. All of the fuel must flow through this 1.5-mm-diameter hole in the seat. The first 

hypothesis involves the potential swelling of the elastomeric seat. If the seat were to swell with 

ethanol exposure, it is conceivable that a restricted fuel flow condition might be reached that would 

limit engine power. The second hypothesis involves the carburetor float. The float that presses the 

metal needle into the seat when the bowl is full is constructed of a hard, white plastic material. If this 

component were to swell or distort, it could conceivably alter the carburetor function. Numerous 

carburetor seats and several carburetor bowls for this engine were acquired for ethanol-blend 

compatibility tests. No results from these experiments are available at this time. Again, no definitive 

cause has been determined for this engine’s apparent problem with E20. 

Poulan leaf blower (pilot study). The Poulan leaf blower was tested to full life at the NREL 

ReFUEL site in Golden, Colorado. Emissions tests on E0 through E20 were conducted in the first 

12 hr of engine operation; then, the engine was aged 8 hr on each fuel.*

 Operators noted that the 

engine began to run poorly during the aging with E15 at about 34 hr. The engine ran very poorly 

during the final E20 phase. Normal operation could not be restored on E0. Figure 3.8 shows mode 1 

engine speed for the duration of the Poulan testing. Rated speed for this engine is 8,000 RPM, 

although it is not surprising that slightly lower speeds would be realized at the higher altitude. 

Degraded performance with E15 at around 30–35 hr is apparent in the figure, continuing with E20 

fuel. Operators noted that idle speed was fairly consistent after the first 12 hr, but speed stability (in 

revolutions per minute) began to degrade at about 30 hr while operating on E15 fuel. At around 45 hr, 

engine operation was noted to be very poor and erratic. Problems with data collection precluded any 

data beyond 47 hr; however, the operators continued to run the engine and noted that at 52 hr the 

engine could not be restarted. It is important to note that this engine has a 50 hr life, and only one 

engine was tested to full life in the pilot study. Given that only one engine was tested, it is not clear 

whether the fuels affected the life of this engine. 

The engine was emissions-tested on E0, E10, E15, and E20 during first 12 hr of life then aged 

8 hr on each fuel. Note the decrease in mode 1 engine speed during durability testing with E15 and 

E20 fuel. 

 *

Plans were to conduct emissions tests after each 8-hour aging interval; however, the emissions measurement system 

used was no longer available at that juncture in the program. 
3-16 

3000

3500

4000

4500

5000

5500

6000

6500

7000

7500

8000

0 10 20 30 40 50

Time (hours)

Engine Speed (RPM)

3000

3500

4000

4500

5000

5500

6000

6500

7000

7500

8000

E0

E10E15

E20

Mode 1

Emissions

Testing Durability Testing

Mode 2

Mode 1 (full power)

Mode 2 (idle)

E0 E10 E15 E20 E0

3000

3500

4000

4500

5000

5500

6000

6500

7000

7500

8000

0 10 20 30 40 50

Time (hours)

Engine Speed (RPM)

3000

3500

4000

4500

5000

5500

6000

6500

7000

7500

8000

E0

E10E15

E20

Mode 1

Emissions

Testing Durability Testing

Mode 2

Mode 1 (full power)

Mode 2 (idle)

E0 E10 E15 E20 E0

Fig. 3.8. Poulan leaf blower engine speed versus time for fuels E0 through E20. 

Stihl FS 90 line trimmer (pilot study). The commercial Stihl line trimmer tested at NREL ran 

poorly on E20, and high idle speed on E15 and E20 led to clutch engagement at idle. In this pilot 

study, no attempts were made to adjust carburetors; rather, engines were tested in their as-received 

condition. It is important to note also that the measured mode 1 engine speed for the Stihl tests was on 

the order of 10,000 RPM, not the rated power condition of 8,000 RPM. 

Briggs and Stratton power washer (full-life study). Six residential Briggs and Stratton power 

washer engines were tested at TRC. Each engine was baselined on E0 using the TRC protocol (see 

footnote b in Table 3.6); then, four of the engines (PW1–PW4) were selected for the aging program. 

All four units ran similarly for the full 125 hr of operation, with each engine run exclusively on one of 

the test fuels (E0, E10, E15, or E20), as illustrated in Table 3.6. Emissions tests on the respective 

dedicated fuels were conducted in the new condition, at half life, and at full life. Operators noted that 

the engines were “missing” at the lighter loads on the TRC protocol on all fuels. 

Because the BASCO protocol*

 was not run until full-life testing was complete, another power 

washer (PW5) was to be tested on all fuels using the BASCO protocol. PW5 was tested successfully 

with E0 fuel but began to run erratically and produce excessive HC emissions during the E10 BASCO 

tests at about 15 hr of total engine operation. Reasons for the engine problem are unknown. 

Honda EB3000c generator (full-life study). Four commercial Honda generators were tested at 

TRC. For the one engine tested on E20, operators noted that the engine was “bouncing off the 

governor” at light loads when testing began, indicating unstable governed speed operation. However, 

after 250 and then 500 hr of aging on E20, the engine ran normally at all loads. 

Weed Eater leaf blower (full-life study). A number of operational issues were observed on 

these inexpensive, residential Class IV leaf blowers, regardless of fuel type. Eight residential Class IV 

Weed Eater Featherlite Blowers were baseline tested on E0 after an initial 2-hr break-in. Four similar 

blowers were selected for the aging program and dedicated to one of the four fuels, in numerical 

order, with B2 dedicated to E0 and B5, B7, and B8 dedicated to E10, E15, and E20, respectively. 

 *

BASCO protocol refers to the Briggs and Stratton Company emissions testing protocol. 
3-17 

Table 3.6. Summary of engine, fuel, and emissions test protocols for full-useful-life (full-life) testing 

Hashed areas indicate no data collected. Fuel column denotes fuel tested at that condition 

(E0, E10, E15, or E20)

Newa

Engine/equipment Full life 

(emissions test protocol) E0b

 baseline Fuel 

Half life 

Fuel Baseline 

PW1 E0 E0 E0 E0 E0 

PW2 E0 E10 E10 E10 E0 

PW3 E0 E15 E15 E15 E0 

PW4 E0 E20 E20 E20 E0 

PW5 E0 

Briggs and Stratton 

power washer

(6-mode dyno test, 

TRC Protocol)c

PW6 E0 

PW1 E0 E0 

PW2 E10 E0 

PW3 E15 E0 

PW4 E20 E0 

PW5 E0 

Briggs and Stratton 

power washer

(6-mode dyno test, 

BASCO Protocol)d

PW6 

G1 E0 E0 E0 E0 E0 

G2 E0 E10 E10 E10 E0 

G3 E0 E15 E15 E15 E0 

Honda generator

(6-mode test, 

generator as engine 

brake) G4 E0 E20 E20 E20 E0 

B2e,f E0 E0 E0 

B5e E0 E10 E10 E10 E0 

B7f,g E0 E15

B3g,h E0 E15

B8e,i E0 E20i

B6k E0 E20 E20 E20 E0 

B1 E0 

Weed Eater blower

(2-mode test, 

blower wheel as 

engine brake) 

B4 E0 

T1 E0 E0 E0 E0 E0 

T2 E0 E10 E10 E10 E0 

T3 E0 E15 E15 E15 E0 

Stihl line trimmer

(2-mode dyno test) 

T4 E0 E20 E20 E20 E0 

a New refers to engines following 2-hr initial break-in. b E0 is federal certification gasoline. 

c TRC protocol allowed engine to run on governor in mode 1, similar to power washer operation in spray mode. d BASCO protocol involved override of governor for wide-open throttle operation in mode 1. Because BASCO 

protocol not initially run on PW1–PW4 in new condition, PW5 tested on BASCO protocol for new engine 

comparison. PW5 failed during E10 testing on BASCO protocol. e Engine initially selected for aging program (B2-E0, B5-E10, B7-E15, B8-E20). 

f B2 failed before full life (50 hr). 

g Failed before half life. 

h B3 replaced B7 as E15 engine after B7 failure. 

i No E20 emissions data obtained from B8 (would not idle). k B6 replaced B8 as E20 engine when B8 would not idle on E20.
3-18 

Figure 3.9 shows the aging timeline for six of the engines. Immediately upon testing, B8 would 

not idle with E20 fuel. To gauge whether this occurrence might be a chronic problem for this engine 

type, a brief operational test was conducted on the remaining four blowers (B1, B3, B4, and B6) to 

observe whether the units would operate properly on E20. Results of this experiment showed that all 

four engines were able to idle with E20, although one of these blowers (B4) would not run 

continuously at WOT. Baseline testing with E0 showed that B4 was the leanest of the group with E0 

fuel (as indicated by lowest CO emissions), suggesting that the additional enleanment from E20 put it 

outside of the stable combustion limits. After this brief operational test, B8 was replaced by B6 as the 

new E20 blower. 

0 10 20 30 40 50

E0 

E10 

E15

E20

Test Fuel

Cumulative Aging (hr)

B2 B5 B7 B3 B8 B6

Half-Life 

25 hrs

Full-Life 

50 hrs

B2 failed during 

aging at 

41:30 hrs 

B3 failed during 

aging at 

21:47 hrs 

B7 failed to restart 

for Half-Life (25 hr)

Emissions testing,

replaced by B3

B8 would not idle 

on E20,

replaced by B6 

Fig. 3.9. Aging timeline for five Weed Eater Featherlite blowers. 

Additional operational problems occurred with the blowers and are summarized in Fig. 3.9 and 

Table 3.5. B7 would not start for its half-life emissions test (25 hr). In an attempt to acquire half-life 

and full-life emissions data for an engine on E15, B3 was selected to replace B7 as the E15-specific 

engine (despite having spent a few minutes running on E20). However, B3 failed before reaching half 

life. B2, running exclusively on E0, stopped working at 41:30 hr. Only two of the five engines 

subjected to the aging program survived to full-life for a 50-hr emissions test—B5 (run on E10) and 

B6 (run on E20). After the completion of the program, an industry peer suggested that the blower 

mounting system may have contributed to premature failure of some of these engines. The way in 

which the pneumatic throttle actuator was mounted may have compromised the carburetor mounting. 

If the carburetor mount was compromised, the resulting air-leak could potentially lead to enleanment 

and engine failure. Inspections of the engines by the manufacturer were planned but not completed 

when this report was prepared. 

Stihl line trimmer (full-life study). The commercial Class IV Stihl line trimmers are equipped 

with three carburetor adjustment screws—one for low-speed mixture, one for high-speed mixture, and 

one for low-idle speed. The as-received condition was “rich-rich” for the two carburetor mixture 

adjustment screws (see Fig. 3.10, H and L at full counterclockwise setting). Instructions to TRC were 

to leave the carburetor screw settings in the as-received condition unless an operational problem was 

noted. Engineers at Stihl were also consulted and they agreed that this setting was a reasonable way to 

proceed with the program. At 225 hr, the idle speed of the E15 and E20 engines had crept up to the 
3-19 

point of clutch engagement. The technicians adjusted the low-idle adjustment (LA) screw and were 

able to bring idle speed back down to 3,000 RPM and eliminate trimmer head spinning during mode 2 

(idle) operation. At the end of the aging program, clutch engagement speed was measured on all four 

Fig. 3.10. Stihl owner’s manual schematic 

showing location of high-speed (H), low-speed (L), 

and low-idle (LA) adjustment screws. (Used with 

permission.) 

trimmers and found to range from 3,300 to 3,600 RPM. With E0 fuel in all trimmers, the range of 

achievable idle speeds was measured to determine the range of authority of the LA screw. With the 

low-speed (L) adjustment screw in the rich (full counterclockwise) position, the LA screw could vary 

idle from below 2,000 RPM to over 4,500 RPM. Setting the L screw to the lean or clockwise position, 

the LA screw could vary idle from around 2,700 RPM to more than 6,000 RPM. The owner’s manual 

contains detailed instructions on adjusting this engine’s carburetor. 

3.2.4 Results and Discussion: Emissions 

As discussed in detail in Sect. 2, five new engines in the pilot study were tested on all four fuels 

(E0, E10, E15, and E20), and the field-aged Honda generator was tested on all but E15. All of the 

engines at TRC were tested on E0; then one of each engine type was dedicated to a specific ethanol 

blend (i.e., E0, E10, E15, or E20) for full-life aging. 

3.2.4.1 ORNL and NREL pilot study: emissions results 

Baseline E0 emissions for each engine and the relative changes in emissions for each of the 

ethanol blends are summarized in Table 3.7. 

• In general, HC emissions decreased with increasing ethanol, while NOX increased. 

• Changes in HC + NOX ranged from a 36% decrease for the Stihl engine with E15 when compared 

to E0 to an 8% increase for the Kohler engine with E20 when compared to E0. 
3-20 

• For the Class I and II four-stroke engines, the large increases in NOX were largely tempered by 

similar decreases in HCs, such that HCs + NOX decreased for three of the engines, while 

increasing with increasing ethanol for the Kohler engine. 

Table 3.7. Baseline E0 emissions and relative change for E10, E15, and E20 for pilot study engines 

Engine Percent change in HC from E0 to: 

type Engine/equipment E0 baseline (g/kWh) E10 E15 E20 

Honda EB3000c generator 6.1 –36.3 –45.0 –53.9 Class I, 

4-stroke Honda EM2500 generatora 13.2 –15.5 –26.1 

Briggs and Stratton generator 7.5 –25.7 –29.9 –39.8 Class II, 

4-stroke Kohler generator 4.0 –30.5 –47.0 –60.0 

Stihl line trimmer (4-mix®) 38.5 –33.8 –39.5 –10.6 

Class IV 

Poulan blower (2-stroke) 38.3 –21.9 –15.1 –25.6 

Numerical average (new engines) 18.9 –29.6 –35.3 –38.0 

Engine Percent change in NOX from E0 to: 

type Engine/equipment E0 baseline (g/kWh) E10 E15 E20 

Class I, Honda EB3000c generator 3.6 18.2 58.7 64.5 

4-stroke Honda EM2500 generatora

 3.3 41.1 87.8 

Class II, Briggs and Stratton generator 1.5 31.2 64.9 130.5 

4-stroke Kohler generator 4.1 32.2 52.8 73.6 

Stihl line trimmer (4-mix®) 1.06 65.1 85.0 26.7 Class IV Poulan blower (2-stroke) 0.15 106.7 53.3 120.0 

Numerical average (new engines) 2.08 50.6 63.0 83.1 

Engine Percent change in HC + NOX from E0 to: 

type Engine/equipment E0 baseline (g/kWh) E10 E15 E20 

Class I, Honda EB3000c generator 9.7 –16.0 –6.2 –9.7 

4-stroke Honda EM2500 generatora

 16.5 –4.1 –3.3 

Class II, Briggs and Stratton generator 9.0 –16.1 –13.9 –11.0 

4-stroke Kohler generator 8.1 1.4 3.9 8.0 

Stihl line trimmer (4-mix®) 39.6 –31.1 –36.2 –9.7 Class IV Poulan blower (2-stroke) 38.5 –21.4 –14.9 –25.0 

Numerical average (new engines) 21.0 –16.6 –13.5 –9.5 

Engine Percent change in CO from E0 to: 

type Engine/equipment E0 baseline (g/kWh) E10 E15 E20 

Class I, Honda EB3000c generator 339 –30.7 –47.7 –56.9 

4-stroke Honda EM2500 generatora

 454 –24.0 –43.0 

Class II, Briggs and Stratton generator 510 –18.3 –22.4 –34.8 

4-stroke Kohler generator 301 –33.1 –53.7 –63.6 

Stihl line trimmer (4-mix®) 630 –40.5 –53.5 –27.8 Class IV Poulan blower (2-stroke) 270 –34.1 –48.9 –61.9 

Numerical average (new engines) 410 –31.3 –45.2 –49.0 

a

Field-aged Honda considered full-useful life. Not included in numerical averages. 

• Given that the HCs + NOX is dominated by the HC emissions for the Class IV handheld engines, 

HCs + NOX decreased for all ethanol blends. 

• CO emissions decreased consistently for all engines with increasing ethanol. 
3-21 

These emissions trends are graphically represented in Figs. 3.11–3.14. The trendlines in 

Figs. 3.11–3.14 represent average data for the new engines, but do not include the field-aged Honda 

data because it was used when testing began and was not tested with E15. As discussed in Sect. 2, the 

brake-specific emissions for the Stihl line trimmer and Poulan blower were estimated from raw 

exhaust concentration measurements and engineering assumptions about exhaust flow rates. Mass 

emissions rates were measured for the generator tests. The electrical load on the generators was 

measured, and a constant generator efficiency of 90% was assumed for calculating the emissions on 

an engine brake-specific basis. HC emissions are as indicated by the FID, and they do not include any 

correction for oxygenated compounds in the exhaust such as ethanol or aldehydes. 

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

E0 E10 E15 E20

HC Emissions (g/kWh)

Honda

Generator

Honda

Generator

(used)

Briggs and

Stratton

Generator

Kohler

Generator

Stihl Line

Trimmer

Poulan

Blower

New Engine

Trendline

No E15 data for used Honda

Fig. 3.11. Hydrocarbon (HC) emissions for pilot study engines versus fuel ethanol 

content. With the exception of the Stihl line trimmer, which ran poorly with E20, HC 

emissions decrease with increasing ethanol. Trendline for average of all five new engines. 

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

E0 E10 E15 E20

NOx Emissions (g/kWh)

Honda

Generator

Honda

Generator

(used)

Briggs and

Stratton

Generator

Kohler

Generator

Stihl Line

Trimmer

Poulan

Blower

New Engine

Trendline

No E15 data for used Honda

 

Fig. 3.12. Nitrogen oxide (NOX) emissions for pilot study engines versus fuel 

ethanol content. NOX increases with increasing ethanol. Poor operation of the Stihl line 

trimmer with E20 caused reduced NOX with that fuel. The Poulan blower is equipped with 

a three-way catalyst that oxidizes hydrocarbons and CO while also reducing NOX

emissions. Trendline for average of all five new engines. 
3-22 

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

E0 E10 E15 E20

HC+NOx Emissions (g/kWh)

Honda

Generator

Honda

Generator

(used)

Briggs and

Stratton

Generator

Kohler

Generator

Stihl Line

Trimmer

Poulan

Blower

New Engine

Trendline

No E15 data for used Honda

Fig. 3.13. Hydrocarbon (HC) + nitrogen oxide (NOX) emissions for pilot 

study engines. Decreasing NOX and increasing HC temper any drastic changes in 

HC + NOX. Trendline for average of all five new engines shows overall decrease 

with increasing ethanol. 

0

100

200

300

400

500

600

700

E0 E10 E15 E20

CO Emissions (g/kWh)

Honda

Generator

Honda

Generator

(used)

Briggs and

Stratton

Generator

Kohler

Generator

Stihl Line

Trimmer

Poulan

Blower

New Engine

Trendline

No E15 data for used Honda

Fig. 3.14. Carbon monoxide emissions for pilot study engines. 

With the exception of the Stihl line trimmer, which ran poorly on E20, CO 

emissions decrease with increasing ethanol. Trendline for average of all five 

new engines. 
3-23 

3.2.4.2 Full-life study emissions results 

Twenty-two engines were baseline tested on E0 at TRC, and 17 of these engines were run to their 

rated full-life period or to failure. Table 3.6 indicates which engines were tested on which fuels. 

Results for all E0 baseline tests at the new and full-life condition are presented in Table 3.8 through 

Table 3.12, with the relative change to the E0 baseline for each engine/ethanol blend combination. 

Table 3.8 and Table 3.9 show the Briggs and Stratton power washer engine results. Table 3.8 has 

results for the TRC protocol tests, and Table 3.9 presents results for the BASCO protocol. These two 

test protocols are discussed in detail in the experimental setup section. Similar information for the 

Honda generators, the Weed Eater blowers, and the Stihl line trimmers are provided in Table 3.10, 

Table 3.11, and Table 3.12, respectively. 

In general, results in the full-life study were similar to those in the pilot study. 

• HC and CO emissions tended to decrease with increasing ethanol content, while NOX tended to 

increase. These trends were observed both at new and full-life conditions. 

• Engine-to-engine differences on E0 fuel were fairly large for the residential engines—in some 

cases as large as the changes due to introduction of the ethanol blends. 

• Changes from the new condition to the full-life condition on the E0 fuel showed a general 

increase in HC and CO, and no dramatic change in NOX. 

Appendix D contains figures for each engine type in the full-life study, showing HC, NOX, HC + 

NOX, and CO emissions for each engine on E0 fuel at the new and full-life conditions and results 

from each engine running its dedicated ethanol blend. In addition, these results are tabulated with 

average, maximum, minimum, and coefficient of variation (COV) for each series of tests. For all 

engines, HC emissions are as indicated by the FID, and do not include any correction for oxygenated 

compounds in the exhaust such as ethanol or aldehydes. 

3.2.5 Results and Discussion: Exhaust, Oil, and Other Temperature Data 

3.2.5.1 ORNL and NREL pilot study: temperature results 

Exhaust temperature, oil temperature (where applicable), and several surface temperatures were 

measured. The largest temperature change noted in any of the engines was in the exhaust. Table 3.13 

shows the baseline E0 temperature for each engine in the pilot study and the change in temperature 

for each of the fuels tested (E10, E15, and E20). The hottest engine condition is reported here, which 

for all but the Kohler engine was observed in the mode 1 condition. The hottest exhaust temperature 

measured on the Kohler V-twin engine was at the fast idle or standby condition. 

As the table indicates, temperature increases between E0 and E20 ranged from 31° to 69°C, but 

only between 8° and 20°C from E10 to E15. Also, the exhaust temperature for the Briggs and Stratton 

engine actually decreased from E10 to E15. 

Figure 3.15 shows the actual temperature measurements for the same data as well as a trendline 

based on the average temperature increases for the five new engines for all ethanol levels. 

Kohler V-twin engine. The temperature results on the Kohler V-twin engine show some 

interesting differences from the single-cylinder-engine generators. While the hottest temperature in 

the single-cylinder engines was in mode 1 or at the peak power condition, the highest exhaust 

temperature measured on the Kohler engine was for the cylinder 1 exhaust manifold at mode 6, the 

no-load (fast idle, or standby) condition. Similarly, the highest temperature rise due to ethanol 

enleanment was for this same cylinder and engine load. 
3-24 

Table 3.8. Baseline Briggs and Stratton power washer engine emissions on the TRC 

protocol at new and full-useful-life (full-life) condition with E0 fuel, and relative 

change for respective ethanol blends 

(“Ethanol blend” refers to E10, E15, or E20, as noted.)

New Full life 

Engine/equipment New E0 

(g/kW-hr) 

Change from 

E0 to ethanol 

blend 

Full-life E0 

(g/kW-hr) 

Change from 

E0 to ethanol 

blend 

HC emissions—TRC protocol

Briggs PW1 (E0 engine) 11.7 11.1 

Briggs PW2 (E10 engine) 12.6 10% 18.2 –21% 

Briggs PW3 (E15 engine) 16.6 –28% 41.4 –21% 

Briggs PW4 (E20 engine) 16.5 3% 32.8 –25% 

Briggs PW5 (alternate) 10.7 

Briggs PW6 (alternate) 20.8 

Numerical average 14.8 25.9 

NOX emissions—TRC protocol 

Briggs PW1 (E0 engine) 2.1 3.7 

Briggs PW2 (E10 engine) 2.0 23% 1.9 4% 

Briggs PW3 (E15 engine) 1.6 22% 1.6 3% 

Briggs PW4 (E20 engine) 1.4 33% 1.6 21% 

Briggs PW5 (alternate) 3.1 

Briggs PW6 (alternate) 2.6 

Numerical average 2.1 2.2 

HC + NOX emissions—TRC protocol

Briggs PW1 (E0 engine) 13.2 14.8 

Briggs PW2 (E10 engine) 14.6 12% 20.1 –19% 

Briggs PW3 (E15 engine) 18.1 –24% 43.1 –20% 

Briggs PW4 (E20 engine) 17.9 5% 34.4 –23% 

Briggs PW5 (alternate) 13.8 

Briggs PW6 (alternate) 23.4 

Numerical average 16.8 28.1 

CO emissions—TRC protocol

Briggs PW1 (E0 engine) 312 164 

Briggs PW2 (E10 engine) 330 –15% 450 –27% 

Briggs PW3 (E15 engine) 347 –46% 724 –37% 

Briggs PW4 (E20 engine) 402 –60% 472 –57% 

Briggs PW5 (alternate) 227 

Briggs PW6 (alternate) 215 

Numerical average 306 453 
3-25 

Table 3.9. Briggs and Stratton power washer engine emissions on the BASCO protocol at new and 

full-useful-life (full-life) condition with E0 fuel, and relative change for respective ethanol blends 

(“Ethanol blend” refers to E10, E15, or E20, as noted.)

New Full life 

Engine/equipment New E0 

(g/kw-hr) 

Change from 

E0 to ethanol 

blend 

Full-life E0 

(g/kw-hr) 

Change from 

E0 to ethanol 

blend 

HC emissions—BASCO protocol

Briggs PW1 (E0 engine) 16.1 

Briggs PW2 (E10 engine) 11.5 47% 

Briggs PW3 (E15 engine) 18.6 –9% 

Briggs PW4 (E20 engine) 16.2 –4% 

Briggs PW5 (alternate) 11.9 

Briggs PW6 (alternate) 

Numerical average 11.9 15.6 

NOX emissions—BASCO protocol

Briggs PW1 (E0 engine) 5.3 

Briggs PW2 (E10 engine) 2.2 13% 

Briggs PW3 (E15 engine) 2.1 22% 

Briggs PW4 (E20 engine) 2.7 73% 

Briggs PW5 (alternate) 4.5 

Briggs PW6 (alternate) 

Numerical average 4.5 3.1 

HC + NOX emissions—BASCO protocol

Briggs PW1 (E0 engine) 21.3 

Briggs PW2 (E10 engine) 13.7 41% 

Briggs PW3 (E15 engine) 20.8 –6% 

Briggs PW4 (E20 engine) 18.9 7% 

Briggs PW5 (alternate) 16.4 

Briggs PW6 (alternate) 

Numerical average 16.4 18.7 

CO emissions—BASCO protocol

Briggs PW1 (E0 engine) 227 

Briggs PW2 (E10 engine) 429 –10% 

Briggs PW3 (E15 engine) 396 –27% 

Briggs PW4 (E20 engine) 332 –53% 

Briggs PW5 (alternate) 241 

Briggs PW6 (alternate) 

Numerical average 241 346 
3-26 

Table 3.10. Baseline Honda generator engine emissions at new and full-useful-life 

(full-life) condition with E0 fuel, and relative change for respective ethanol blends 

(“Ethanol blend” refers to E10, E15, or E20, as noted.)

New Full life 

Engine/equipment New E0 

(g/kW-hr) 

Change from 

E0 to ethanol 

blend 

Full-life E0 

(g/kW-hr) 

Change from 

E0 to ethanol 

blend 

HC emissions

Honda G1 (E0 engine) 5.2 6.5 

Honda G2 (E10 engine) 5.1 –17% 5.3 –16% 

Honda G3 (E15 engine) 6.2 –30% 8.8 –26% 

Honda G4 (E20 engine)a 5.5 150% 9.3 –35% 

Numerical average 5.5 7.5 

NOX emissions

Honda G1 (E0 engine) 3.7 3.7 

Honda G2 (E10 engine) 3.6 42% 4.0 40% 

Honda G3 (E15 engine) 4.4 44% 3.8 68% 

Honda G4 (E20 engine) 5.0 93% 4.2 102% 

Numerical average 4.2 3.9 

HC + NOX emissions

Honda G1 (E0 engine) 9.0 10.2 

Honda G2 (E10 engine) 8.8 7% 9.2 8% 

Honda G3 (E15 engine) 10.6 1% 12.6 2% 

Honda G4 (E20 engine)a 10.5 123% 13.5 7% 

Numerical average 9.7 11.4 

CO emissions

Honda G1 (E0 engine) 329 374 

Honda G2 (E10 engine) 306 –28% 320 –31% 

Honda G3 (E15 engine) 310 –34% 359 –37% 

Honda G4 (E20 engine) 270 –39% 335 –60% 

Numerical average 304 347 

a

Unusually high HC emissions with E20 due to unstable speed governor operation at light loads. 
3-27 

Table 3.11. Baseline Weed Eater Featherlite blower engine emissions at new and full-useful-life 

(full-life) condition with EO fuel, and relative change for respective ethanol blends 

(“Ethanol blend” refers to E10, E15, or E20, as noted.) 

New Full life 

Engine/equipment New E0 

(g/kW-hr) 

Change from 

E0 to ethanol 

blend 

Full-life E0 

(g/kW-hr) 

Change from 

E0 to ethanol 

blend 

HC emissions

Weed Eater B1 (alternate) 28.4 

Weed Eater B2 (E0 engine) 47.6 

Weed Eater B3 (E15 engine)a 42.4 –22% 

Weed Eater B4 (alternate) 36.5 

Weed Eater B5 (E10 engine) 57.8 –20% 48.1 –25% 

Weed Eater B6 (E20 engine)b 49.8 –32% 43.3 –18% 

Weed Eater B7 (E15 engine) 38.4 –19% 

Weed Eater B8 (E20 engine) 46.6 

Numerical average 43.4 45.7 

NOX Emissions

Weed Eater B1 (alternate) 0.9 

Weed Eater B2 (E0 engine) 0.3 

Weed Eater B3 (E15 engine)a 0.2 48% 

Weed Eater B4 (alternate) 1.3 

Weed Eater B5 (E10 engine) 0.2 19% 0.3 27% 

Weed Eater B6 (E20 engine)b 0.3 203% 1.1 –12% 

Weed Eater B7 (E15 engine) 0.2 399% 

Weed Eater B8 (E20 engine) 0.3 

Numerical average 0.5 0.7 

HC + NOX Emissions

Weed Eater B1 (alternate) 29.3 

Weed Eater B2 (E0 engine) 47.9 

Weed Eater B3 (E15 engine)a 42.6 –21% 

Weed Eater B4 (alternate) 37.8 

Weed Eater B5 (E10 engine) 58.0 –19% 48.4 –25% 

Weed Eater B6 (E20 engine)b 50.0 –31% 44.4 –18% 

Weed Eater B7 (E15 engine) 38.6 –17% 

Weed Eater B8 (E20 engine) 46.8 

Numerical average 43.9 46.4 

CO Emissions

Weed Eater B1 (alternate) 43 

Weed Eater B2 (E0 engine) 366 

Weed Eater B3 (E15 engine)a 355 –42% 

Weed Eater B4 (alternate) 19 

Weed Eater B5 (E10 engine) 448 –32% 314 –46% 

Weed Eater B6 (E20 engine)b 353 –76% 83 1% 

Weed Eater B7 (E15 engine) 239 –95% 

Weed Eater B8 (E20 engine) 369 

Numerical average 274 199 

a

B3 was replacement E15 engine after failure of B7. 

b

B6 was replacement E20 engine when B8 would not idle on E20. 
3-28 

Table 3.12. Baseline Stihl line trimmer engine emissions at new and full-useful-life 

(full-life) condition with E0 fuel, and relative change for respective ethanol blends 

(“Ethanol blend” refers to E10, E15, or E20, as noted.) 

New Full life 

Engine/equipment New E0 

(g/kW-hr) 

Change from 

E0 to ethanol 

blend 

Full-life E0 

(g/kW-hr) 

Change from 

E0 to ethanol 

blend 

HC emissions

Stihl T1 (E0 engine) 33.6 76.4 

Stihl T2 (E10 engine) 29.9 –11% 65.6 –19% 

Stihl T3 (E15 engine) 28.5 –29% 71.3 –17% 

Stihl T4 (E20 engine) 26.3 –37% 68.8 –33% 

Numerical average 29.6 70.5 

NOX emissions

Stihl T1 (E0 engine) 3.3 3.7 

Stihl T2 (E10 engine) 4.1 11% 4.8 39% 

Stihl T3 (E15 engine) 3.2 116% 2.5 184% 

Stihl T4 (E20 engine) 2.6 70% 3.0 114% 

Numerical average 3.3 3.5 

HC + NOX emissions

Stihl T1 (E0 engine) 36.9 80.1 

Stihl T2 (E10 engine) 33.9 –9% 70.4 –15% 

Stihl T3 (E15 engine) 31.7 –14% 73.7 –10% 

Stihl T4 (E20 engine) 28.9 –27% 71.8 –27% 

Numerical average 32.9 74.0 

CO emissions

Stihl T1 (E0 engine) 347 591 

Stihl T2 (E10 engine) 285 –7% 461 –20% 

Stihl T3 (E15 engine) 408 –39% 712 –40% 

Stihl T4 (E20 engine) 335 –48% 603 –40% 

Numerical average 344 592 

Table 3.13. Change in exhaust temperature with ethanol blends for hottest 

engine condition for six pilot study engines 

Maximum exhaust temperature 

increase from E0 

Rise in degrees Celsius Engine/equipment Baseline 

E0 

E10 E15 E20 

Honda EB3000c generator 654 24 33 41 

Honda EM2500 generatora 667 16 31 

Briggs and Stratton generator 689 33 19 42 

Kohler generator 835 22 42 69 

Stihl line trimmer 726 42 47 38 

Poulan blower 542 29 37 54 

Numerical average (new engines) 689 30 36 49 

a

Field-aged Honda generator not tested on E15, not included in numerical average. 
3-29 

500

550

600

650

700

750

800

850

900

950

E0 E10 E15 E20

Exhaust Port Temperature (C)

Honda

Generator

Honda

Generator

(used)

Briggs and

Stratton

Generator

Kohler

Generator

Stihl Line

Trimmer

Poulan

Blower

New Engine

Trendline

No E15 data for used Honda

Fig. 3.15. Exhaust port temperature for pilot study engines at hottest condition 

versus ethanol blend level. 

The V-twin Kohler was found to have uneven cylinder-to-cylinder fuel balance, which causes 

asymmetrical exhaust manifold temperatures. The exhaust manifold temperature results for both 

cylinders and for all test modes and fuels are shown in Fig. 3.16. To confirm this apparent fueling 

Fig. 3.16. Exhaust temperature versus mode for all fuels and individual 

cylinders of Kohler generator. Enrichment at higher loads cools both exhaust manifolds, 

but uneven fuel:air distribution leads to higher no-load temperatures in cylinder 1 from a 

less-rich condition than cylinder 2. Cylinder 2 is hottest at half load.
3-30 

imbalance, the CO concentration for each cylinder was measured individually at three operating 

conditions, as shown in Fig. 3.17 (with E0 fuel). The results indicate uneven distribution of fuel 

between the two cylinders and explain the unusual manifold temperature results shown in Fig. 3.16. 

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

Full Load Half Load No Load

Cylinder-Out CO Concentration (%)

Cylinder 1 Cylinder 2

Fig. 3.17. Individual cylinder CO concentration for E0 fueling at 

three loads for Kohler generator. 

The highest temperature in cylinder one (and overall for this engine) occurs at the no-load or fast 

idle (standby) condition. As electrical loads are applied and the governor opens the throttle to increase 

air flow and engine power in mode 1 (full load), the carburetor is also decreasing the net fuel:air 

equivalence ratio (overall richer combustion). Richer combustion can increase engine power and also 

cool the engine. The uneven cylinder-to-cylinder distribution results in much richer combustion in 

cylinder 2 at the fast-idle and full-load conditions, but much leaner (less rich) combustion at half load. 

Cylinder 1 has relatively consistent fueling, with CO emissions in the 4.5% to 6% range from fast idle 

to full load, while the CO concentration from cylinder 2 was only 2% at half load with E0 fuel, 

leading to the highest temperatures for this cylinder at that condition. The potential severity of this 

problem for 2-cylinder engines is uncertain, as the extent of engine-to-engine variability is unknown 

at this time. 

Carbon monoxide emissions vary widely in cylinder 2 as a function of load while remaining 

fairly consistent in cylinder 1, indicating a much broader variation of fuel:air distribution in 

cylinder 2. The less rich cylinder (lower CO emissions) is always hotter (see Fig. 3.16). 

3.2.5.2 Full-life study temperature results 

As in the ORNL/NREL pilot study, exhaust temperature, oil temperature (where applicable), and 

several surface temperatures were measured on all small engines tested in the full-life study at TRC. 

General observations are as follows. 

• In most cases, the exhaust temperature increased with higher ethanol content. 

• Engine-to-engine differences on E0 fuel were fairly large for the residential engines—in some 

cases as large as the changes due to introduction of the ethanol blends. 

• In general, engines exhibited lower exhaust temperatures on all fuels at full life in comparison to 

the new condition. 
3-31 

• The relative change in temperature as ethanol increases appears more distinct at the full-life 

condition for most engines. 

• As with the engines tested at ORNL and NREL, the largest temperature change noted in any of 

the engines was in the exhaust. 

• Full-life testing revealed no engine failures that could be attributed to increased thermal stress on 

any of the engines. 

Table 3.14 shows E0 baseline temperatures for the highest temperature mode and the temperature 

change observed with the respective ethanol blend run in each engine tested in the full-life study. The 

highest temperature for the Class I engines was mode 6, the fast-idle or stand-by condition. The 

hottest condition for the Class IV engines was mode 1, or the full-power condition. Figures 3.18 and 

3.19 display temperature data from the Briggs and Stratton engines and Stihl line trimmers in graphic 

representation. These figures are repeated in Appendix D along with similar figures showing data 

from the other two engine types tested at TRC. 

Results for the commercial Class I Honda generators demonstrate that the engine-to-engine 

differences on E0 are not as large as those for the residential power washer engines. The decrease in 

exhaust temperature for the Honda generator run on E20 was likely due to the erratic operation of this 

unit at light loads in the new condition. Operators reported the engine speed fluctuating due to 

unstable governor operation with E20. This problem did not recur during half-life or full-life 

emissions tests on this engine. 

Despite the dearth of full-life data on the Weed Eater Featherlite blowers due to three engine 

failures, the results still show a general decrease in exhaust temperature with age and maintain the 

increase in operating temperature with increasing ethanol. 

All Stihl engines ran considerably cooler at the full-life condition but still showed a slight 

increase in exhaust temperature with ethanol addition. During the full-life dynamometer tests, it was 

noted that all four Stihl engines had lost some 30% to 35% of their rated power in mode 1, likely 

contributing to the increase in brake-specific emissions and lower exhaust temperature. Consultation 

with Stihl indicated that normal power loss at full life is typically less than 10% when the 

maintenance outlined in the owner’s manual is closely followed, including valve adjustment and 

cleaning of the combustion chamber. A final set of E0 tests on these four engines was conducted after 

recommended cleaning and valve adjustment. Three of the trimmers returned to normal full-life 

power specification (trimmers 1, 2, and 4, aged on E0, E10, and E20, respectively), exhibiting mode 1 

power at 90% to 95% of the power rating when new. The E15 unit, trimmer 3, was not able to make 

normal full-life power, exhibiting a power loss of about 18%. This unit was retested after carburetor 

and air cleaner swaps and rechecking valve adjustment, but power output did not recover. The engine 

started and ran normally except for the power loss. Reasons for this engine’s power loss are not 

known at this time. The four units were returned to Stihl for examination. 
3-32 

Table 3.14. Change in exhaust temperature for engines in full-useful-life (full-life) study for hottest 

engine condition. Class I engines at fast idle condition (mode 6), Class IV engines 

at rated power condition (mode 1) [Exhaust port temperature (°C)]

New (mode 6) Full life (mode 6) 

Engine/equipment New E0 temp. 

Change from 

E0 to ethanol 

blenda

Full-life E0 

temp. 

Change from 

E0 to ethanol 

blenda

Briggs and Stratton power washers (residential Class I) 

Briggs PW1 (E0 engine) 650 613 

Briggs PW2 (E10 engine) 654 25 547 12 

Briggs PW3 (E15 engine) 654 10 607 25 

Briggs PW4 (E20 engine) 680 0 609 28 

Briggs PW5 (alternate) 692 

Briggs PW6 (alternate) 540 

Numerical average (PW1-4) 660 594 

Honda generators (commercial Class I) 

Honda G1 (E0 engine) 742 700 

Honda G2 (E10 engine) 755 0 722 9 

Honda G3 (E15 engine) 747 10 715 28 

Honda G4 (E20 engine)b 761 –35 717 23 

Numerical average 751 713 

Weed Eater blowers (residential Class IV) 

Engine/equipment New (mode 1) Full-life (mode 1) 

Weed Eater B1 574 

Weed Eater B2 (E0 engine) 576 

Weed Eater B3 (E15 engine)c 580 14 

Weed Eater B4 577 

Weed Eater B5 (E10 engine) 574 6 551 23 

Weed Eater B6 (E20 engine)d 580 21 537 5 

Weed Eater B7 (E15 engine) 563 54 

Weed Eater B8 (E20 engine) 558 

Numerical average 573 544 

Stihl line trimmers (commercial Class IV) 

Stihl T1 (E0 engine) 717 675 

Stihl T2 (E10 engine) 725 8 669 19 

Stihl T3 (E15 engine) 688 50 628 24 

Stihl T4 (E20 engine) 761 28 642 43 

Numerical average 723 653 

a Ethanol blend denotes E10, E15, or E20. 

b Honda G4 experienced unstable speed on governor at light loads with E20 when new. 

c

 Replaced B7 as E15 blower after B7 failure. 

d Replaced B8 as E20 blower because B8 would not idle with E20. 
3-33 

400

450

500

550

600

650

700

E0 E10 E15 E20

Exhaust Port Temperature (C)

400

450

500

550

600

650

700

PW1 (new) PW2 (new) PW3 (new) PW4 (new)

PW1 (full life) PW2 (full life) PW3 (full life) PW4 (full life)

new engine

trendline

Full-life

trendline

Fig. 3.18. Exhaust port temperature for Briggs and Stratton power 

washer engines at mode 6 condition versus ethanol blend level. Solid colors 

represent tests at the new condition while striped bars of the same color represent 

the same engine at the full-useful-life (full-life) condition. Exhaust temperature 

increases for all engines with ethanol addition. 

550

600

650

700

750

800

E0 E10 E15 E20

Exhaust Port Temperature (C)

550

600

650

700

750

800

Stihl T1 (new) T2 (new) T3 (new) T4 (new)

T1 (full life) T2 (full life) T3 (full life) T4 (full life)

new engine

trendline

Full-life

trendline

Fig. 3.19. Exhaust port temperature for Class IV Stihl line trimmer 

engines at hottest condition (mode 1) at new and full-useful-life (full-life) 

condition. Solid colors represent tests at the new condition while striped bars of 

the same color represent the same engine at the full-life condition. Full-life 

temperatures were considerably cooler for all Stihl engines. 
4-1 

4. NEXT STEPS 

Given the importance of expanding the nation’s use of renewable fuels and the new renewable 

fuel mandate set forth in the Energy Independence and Security Act of 2007, DOE and others 

recognize the need to consider a variety of means for bringing such fuels to market. While ethanol is 

the most widely used renewable fuel in the United States, the E10 market—which takes up the vast 

majority of ethanol used today—will be saturated in the near future. Given that reality, DOE is 

working to expand the distribution and use of E85 and to simultaneously investigate the potential of 

using intermediate ethanol blends (e.g., E15, E20) in conventional vehicles and engines. 

This report summarizes findings to date from DOE’s first phase of intermediate ethanol blends 

testing on vehicles and other engines. Recognizing the need for a wide range of additional tests, DOE 

is sponsoring a number of other studies. Current studies, some of which are being conducted in 

partnership with other organizations, are summarized below. Additional studies may be conducted as 

needed, subject to available funding. 

4.1 EMISSIONS AND CATALYST TEMPERATURE 

This report provides results of immediate effects of mid-level ethanol blends on vehicle and small 

engine emissions and catalyst temperatures. 

4.2 EMISSIONS OF VARIOUS GASOLINES AND ETHANOL BLENDS 

This task, performed in collaboration with EPA and CRC, will assess the impacts of varying Reid 

vapor pressure (RVP), T50, T90, and aromatic content of gasoline and multiple match-blended 

ethanol/gasoline fuels on vehicle tailpipe emissions. Data on criteria pollutants [HC, CO, NOX, and 

particulate matter (PM)], ethanol, and carbonyl compounds will be collected. Detailed HC speciation 

data will be collected for all vehicles tested in this task. Detailed PM and semi-volatile organic 

compound data will be collected for a subset of the fuels. 

4.3 EVAPORATIVE EMISSIONS 

This study, being conducted in collaboration with CRC (Project E-77), will measure evaporative 

emissions associated with testing gasoline fuels of varying RVP (volatility) and ethanol blends. Fuels 

with defined vapor pressures and ethanol content ranging from 0% to 20% will be tested on multiple 

model year vehicles. Static permeation, running loss, hot soak, and diurnal emissions will be 

measured. 

4.4 FULL-USEFUL-LIFE EMISSIONS 

This task, in collaboration with CRC (Project E-87), will assess the impact of intermediate 

ethanol blends on tailpipe emissions over the full useful life of vehicles. In Phase I, the study will 

initially screen 25 vehicles for catalyst performance and key temperatures during open-loop (WOT) 

operation. Full-life studies on numerous engine families are planned in Phase II. 
4-2 

4.5 DRIVEABILITY 

This task, conducted in collaboration with CRC (Project CM-138), evaluated impacts of 

intermediate blends on the driveability of six late-model non-FFVs and of various E85 fuels in 

20 FFVs. The standard driveability test, developed by CRC, was used. Fuels tested in the study 

include E0, E15, and E20 with prescribed vapor pressures. The final report for this study is available 

on the CRC web site.*

 Additional driveability studies may be conducted in the future. 

4.6 FUEL SYSTEM MATERIALS COMPATIBILITY 

This task, conducted in collaboration with CRC (Project AVFL-15), will evaluate the durability 

of wetted components of fuel systems in non-FFVs when exposed to different ethanol blends. This 

study will measure effects on all materials found in the fuel system, including plastics, elastomers, Orings, and hose materials. 

4.7 FUTURE REPORTS 

As results from these studies become available, DOE will issue additional reports with analyses 

as well as core data. 

DOE will continue to work closely with EPA, industry partners, and others to ensure that testing 

is sound and targeted at providing data needed to assess the effects of intermediate ethanol blends on 

conventional vehicles as well as other engines. 

 

*

 “2008 CRC Cold-Start and Warm-Up E85 and E15/E20 Driveability Program – Final Report,” CRC Report 

No. 652, October 2008. 
APPENDICES 

A-1 

APPENDIX A 

VEHICLE TEST EQUIPMENT, PROCEDURES, AND RELEVANT 

VEHICLE EMISSIONS STANDARDS 

The equipment used during this study can be broken down into the following categories. 

Measurement equipment

• Emissions 

• Exhaust and catalyst temperatures 

Test cell equipment

• Transportation Research Center (TRC) 

• Oak Ridge National Laboratory (ORNL) 

• National Renewable Energy Laboratory (NREL)/ Colorado Department of Public Health and 

Environment (CDPHE) 

A.1 EMISSIONS MEASUREMENT 

All laboratories measured emissions via full-flow dilution per CFR 40 part 86 guidelines. Phase 

concentrations of CO, oxides of nitrogen (NOX), total hydrocarbons (THC), CH4, and CO2 were 

measured by conventional analyzers. Modal emissions (second-by-second gas concentrations) at 

engine-out, tailpipe, and tunnel locations were recorded at ORNL, and modal tunnel data were 

collected at TRC. All available data from each vehicle’s Engine Control Unit (ECU), such as engine 

revolutions per minute, intake manifold pressure, etc., were collected at ORNL and CDPHE via the 

Assembly Line Diagnostic Link (ALDL) for subsequent analysis. 

All labs sampled aldehydes (including formaldehyde and acetaldehyde) using dilution tunnel 

sample taps with gas drawn through dinitrophenylhydrazine- (DNPH)-treated silica gel cartridges at a 

rate of approximately 1 L/min.*

 DNPH cartridges were then post-processed by eluting with 

acetonitrile and analyzing by high-performance liquid chromatography. Aldehyde emissions are 

important for several reasons. Formaldehyde is a regulated pollutant and acetaldehyde, although not 

yet regulated by the U.S. Environmental Protection Agency (EPA), is listed by EPA as a hazardous 

air pollutant. In addition, these oxygenated compounds are reactive in the atmosphere and must be 

included when calculating non-methane organic gas (NMOG) emissions. The NMOG calculation 

method is described in Sect. A.3. 

Exhaust gas ethanol concentration was measured by all laboratories using the Innova 

Photoacoustic Multi-gas Analyzer supplied by California Analytical Instruments. This method, 

developed and documented by Loo and Parker†

 and now accepted by EPA, was used to batch sample 

individual phase emissions for ethanol concentration. Because this method includes the coupled 

effects of other gas species on ethanol measurement, the instrument must be calibrated and configured 

to measure these interfering species. Consequently, appropriate optical filters must be installed and 

calibrated to measure interference gases such as water vapor, ammonia, and CO2, and gas sampling 

and interference corrections must be enabled in the instrument during operation. 

Unfortunately, for the data acquired at TRC using two new instruments, these interference 

measurements were not properly enabled so errors in measurement of ethanol in the exhaust were 

 *

Siegl, W. O., J. F. O. Richert, T. E. Jensen, D. Schuetzle, S. J. Swarin, J. F. Loo, A. Prostak, D. Nagy, A. M. 

Schlenker, “Improved Emissions Speciation Methodology for Phase II of the Auto/Oil Air Quality Improvement Research 

Program—Hydrocarbons and Oxygenates,” Society of Automotive Engineers Technical Series 930142 (1993). 

†

Loo, Jeffrey F., and David T. Parker, “Evaluation of a Photoacoustic Gas Analyzer for Ethanol Vehicle Emissions 

Measurement,” Society of Automotive Engineers, 2000-01-0794 (2000). 
A-2 

experienced. Estimates of ethanol gas concentrations for the six vehicles tested at TRC were based on 

volume percent ethanol in the gasoline and measured THC emissions. This estimation method was 

developed using exhaust ethanol data acquired from the NREL dataset at both 50° and 75°F. This 

dataset included 24 points—three vehicles, four fuels, and two temperatures. These data showed 

strong correlation with a coefficient of determination, R2

, of greater than 95%. While not as accurate 

as direct ethanol measurement, this method is believed to provide a reasonable estimate for the 

purposes of NMOG calculation. This method was also used to estimate ethanol emissions for the 

vehicles tested at ORNL. The relatively high dilution ratio used for ORNL testing led to ethanol 

measurements near the detection limit of the Innova. This problem was exacerbated by apparent 

“hang up” of the ethanol in the sample system. 

Hydrocarbon (HC) speciation was also performed for selected tests at ORNL and for all Phase 1 

measurements at NREL/CDPHE. This measurement was accomplished at both laboratories by 

drawing dilute tunnel gas into an evacuated canister of passivated stainless-steel construction. This 

sample gas was then analyzed by gas chromatography/mass spectrometry for pollutant quantification 

and identification. An analysis of this data was not available for this report. 

A.1.1 Exhaust and Catalyst Temperature Measurements 

A wide-range universal exhaust gas oxygen sensor (UEGO) was used on each vehicle to record 

real-time fuel:air equivalence ratio. This information is useful to understand how each test vehicle’s 

fuel control system responded to the oxygenated fuels. 

Several key exhaust temperatures were also measured on each vehicle at the following locations. 

• Engine-out or precatalyst, measured using 1/8 in. thermocouple located upstream of catalyst core 

or in exhaust manifold. 

• Catalyst core, measured using 1/16 in. or 1/8 in. thermocouple installed directly into catalyst core 

at 1 in. from leading face. 

• Between 1st and 2nd catalysts (for vehicles with dual catalyst configuration), measured using 

1/8 in. thermocouple located between catalysts. 

• Second catalyst core, measured using 1/16 in. or 1/8 in. thermocouple installed directly into 

second catalyst core at 1 in. from leading face. 

• Catalyst outlet, measured using 1/8 in. thermocouple located 6 in. downstream of catalyst outlet. 

 

Each vehicle’s exhaust system was removed so that thermocouples, UEGO ports, and exhaust 

sample ports could be installed. Figure A.1 shows an example exhaust system modified for this 

program from a 4-cylinder Toyota Camry. Only the exhaust manifold and first catalyst are shown. 

Similar temperature and sample ports were installed in the second catalyst and outlet pipe. 

A.1.2 Vehicle Laboratory at TRC 

The chassis dynamometer used at TRC was an AVL 48-in. (1.22-m), dual-axle 2-wheel 

drive/4-wheel drive motor/brake unit. 

Emissions were measured using Horiba 200 series analyzers. 

• CO2 and CO were measured using non-dispersive infrared (NDIR) instruments. 

• NOX was measured by a chemiluminescence detector. 

• THC was measured using a flame ionization detector (FID). 

• CH4 was measured using a gas chromatography analyzer. 
A-3 

Factory EGO port

Added UEGO port

Added Thermocouple ports Added Engine-out sample port

1 inch

deep

Fig. A.1. Example of vehicle exhaust system instrumentation, including universal exhaust 

gas oxygen sensor (UEGO) and temperature and exhaust gas sample ports. 

A.1.3 Vehicle Laboratory at ORNL 

The chassis dynamometer at ORNL’s Fuels, Engines, and Emissions Research Center was of the 

twin-roll type [21.625 in. in diameter (0.55 m)] with an eddy current brake. 

Conventional emissions measurements were conducted with analyzers from California Analytical 

Instruments. 

• CO2 and CO were measured using NDIR 

• NOX was measured by chemiluminescence detector 

• THC and CH4 were measured using a FID with methane cutter. 

A.1.4 Vehicle Laboratory at CDPHE 

The chassis dynamometer at CDPHE’s Aurora Emissions Technical Center was a Horiba 48-in. 

(1.22-m) independent-axle, 2-wheel drive motor/brake unit. 

Emissions were measured using Horiba series 200 emissions analyzers. 

• CO2 and CO were measured using NDIR 

• NOX was measured by chemiluminescence detector 

• THC and CH4 were measured using a flame ionization detector with methane cutter. 

A.2 TEST PROCEDURES 

The test procedures for each different fuel tested consisted of the following. 

• Emissions and fuel economy testing prep cycles 

• Vehicle emissions testing 
A-4 

• Emissions control system temperature testing 

• Statistical analysis of emissions and fuel economy data 

The following fuel testing sequence was followed for all vehicles. 

1. E0 baseline 

2. E20 

3. E10 

4. E15 

5. E0 repeat 

Initial E0 testing was conducted to obtain a performance baseline before introduction of ethanol 

blended fuels. E20 fuel was tested immediately following E0 to precipitate any possible malfunction 

indicator light (MIL) occurrences due to fuel trim effects or clogged filters resulting from the 

increased solvency of E20 fuel. Repetition of E0 fueling at the conclusion of emissions testing was to 

test for any drift in the E0 data over time and to see whether the short-term exposure to intermediate 

ethanol blends or the wide-open-throttle (WOT) testing might have caused any notable change to the 

emissions control system function. 

A.2.1 Emissions Test Preparatory cycles 

Before the start of testing, each vehicle was inspected to ensure all emission control hardware was 

intact, and an ECU scan was conducted to confirm no on-board diagnostic (OBDII) faults were 

present. Each vehicle then underwent an initial crankcase oil, oil filter, and air filter replacement. 

Engine oil and filters were per the manufacturer’s recommendations. Each vehicle was then driven 

through three US06 drive cycles to stabilize the engine oil by eliminating the higher volatility 

components that may have an effect on vehicle emissions. Each vehicle’s ECU was again scanned 

before initiation of testing to confirm there were no existing or pending OBDII faults. The following 

list summarizes the vehicle preparation procedure. 

A.2.1.1 Initial acquisition preparation 

1. Check for pending and existing OBDII faults. Consult program technical monitor if any exist. 

2. Change oil, oil filter, and air filter using OEM recommended product. 

3. Record oil sump level in vehicle log book. 

4. Condition new oil by running three consecutive US06 test cycles on market gasoline. 

5. Record oil sump level following oil conditioning. 

6. Recheck for any existing or pending MIL codes. 

A.2.1.2 Baseline emissions and fuel economy check 

Following initial preparation, vehicles at CDPHE and ORNL were tested on the Federal Test 

Procedure (FTP) and Highway Fuel Economy Test protocols to determine city and highway fuel 

economy for comparison to published EPA data. Provided these evaluations yielded fuel economy 

results within 10% of EPA database values, dynamometer setup and vehicle operation were 

considered to be acceptable. 
A-5 

A.2.1.3 Fuel change and adaptation to new fuel 

Following the initial acquisition preparation, each vehicle was fueled with the appropriate test 

fuel and adapted according to the fuel change protocol described below. This fuel change protocol 

was performed for every fuel change throughout the test program. 

1. Drain tank using in-tank fuel pump. 

2. Key on for 30 s. 

3. Confirm gauge reading and allow vehicle to register new fueling event. 

4. Add half tank of new test fuel. 

5. Drive 550 (5 min at 50 mph), then run double US06 test cycles. 

6. Drain tank using in-tank fuel pump. 

7. Key on for 30 s. 

8. Confirm gauge reading and allow vehicle to register new fueling event. 

9. Add half tank of new test fuel. 

10. Proceed to vehicle emissions testing. 

A.2.1.4 Vehicle emissions testing 

After completion of the test preparation cycles, emissions tests were performed using the LA92 

drive cycle. The LA92, also known as the unified cycle, is used for in-use emissions testing in some 

areas of the country. Acceleration rates and speeds for the LA92 are higher than those of the FTP but 

lower than those of the US06, and thus it is generally considered to be more typical of real-world 

driving, even though the FTP and US06 are certification tests and the LA92 is not. The LA92 cycle 

was chosen for the current test program because it is being used in a joint EPAct/DOE program. 

A.2.1.5 LA92 drive cycle 

The LA92 is a three-phase test, much like the FTP, and the FTP weighting factors for each phase 

were used in the calculation of composite results. The entire 1,736-s drive cycle of the LA92 is shown 

in Fig. A.2. 

0

10

20

30

40

50

60

70

80

0 200 400 600 800 1000 1200 1400 1600 1800

Time (sec)

Speed (mph)

LA92 Bag-1

300 sec

LA92 Bag-2

1136 sec

LA92 Bag-3

300 sec

10 Minute 

Delay

Fig. A.2. LA92 drive cycle. 
A-6 

Phase 1 

The first phase of the LA92 is 300 s, compared with 505 s for the standard FTP. Consequently, 

LA92 Phase 1 emissions are more dominated by cold-start transient and tend to be much higher than 

the FTP on a gram-per-mile basis. The 300-s Phase 1 includes numerous moderate accelerations with 

a maximum speed of just over 40 mph. 

Phase 2 

Phase 2 is 1,136 s and includes two moderate-to-heavy accelerations with top speeds just over 

60 mph. 

Phase 3

Phase 3 is a repeat of Phase 1, but with a 10-min engine-off soak after Phase 2. Therefore, 

Phase 3 contains a hot start instead of a cold start. 

A.2.1.6 Vehicle emissions test procedure 

The following protocol was executed after the preparation cycles and before the first emissions 

test run on each fuel. The second and third emissions tests followed consecutively without a repeat of 

the entire preparation cycle. 

1. Vehicle precondition: Drive 5 min at 50 mph; then, complete LA4*

 test cycle followed by LA92 

test cycle. Idle vehicle in Park for 2 min following completion of LA92, then key off. 

2. Note: Vehicle precondition must be performed following overnight vehicle soak at intended test 

temperature. 

3. Soak vehicle overnight. 

4. Execute LA92 emissions test protocol. 

5. Idle vehicle in Park for 2 min following each test; then, key off. 

6. Push vehicle (with key in off position) from chassis dynamometer to parking/staging area. 

7. Subsequent vehicle tests at the same test conditions may be performed with only an LA92 

precondition. Previous vehicle tests may be used as preconditions provided test temperatures are 

equivalent. 

8. Check for existing or pending OBDII faults following each LA92 test and record results in 

vehicle log book. 

This protocol was agreed upon following consultation with several technical peers. 

At the conclusion of all emissions tests for a given fuel, WOT test protocols were conducted to 

evaluate each vehicle’s control system fuel trim strategy during enrichment (i.e., WOT operation). 

A.2.2 Catalyst Temperature Test Procedure 

Exhaust and catalyst temperature testing was subdivided into three categories. 

• WOT excursion on level ground 

• WOT hill climb 

• Closed-loop at high engine load 

A.2.2.1 Wide-open-throttle excursion on level ground 

The WOT protocol used predominantly in this test series to evaluate open-loop enrichment 

effects was based on the EPA mobile source air toxics sulfur purge cycle originally developed under 

 *

The LA4 is a 1,372 s cycle that consists of the first two phases of the Federal Test Procedure. 
A-7 

the CRC E-60 program. The CRC WOT protocol was slightly modified for this program. The original 

CRC E-60 protocol called for WOT accelerations starting from 30 mph, whereas the modified 

protocol used a standing start WOT acceleration to allow longer time at WOT conditions. Because 

this longer WOT excursion would likely produce higher dilution tunnel temperatures, a 90-s idle 

period (0 mph) was added between successive WOTs. This modified protocol is depicted in Fig. A.3. 

0

10

20

30

40

50

60

70

80

90

100

0 200 400 600 800 1000 1200 1400

Time (sec)

Vehicle Speed (mph)

300 sec @ 55 mph

60 sec

@

30 mph

- 15 sec minimum at 80 mph for each cycle

- 60 sec at 30 miles between excursions

- 90 sec at idle between excursions for cooldown

Cycle to be 

executed twice for 

full WOT protocol

Fig. A.3. Modified Coordinating Research Council E-60 wide-open-throttle drive cycle. 

The modified CRC WOT cycle was executed for each vehicle at all three test sites following fuel 

adaptation and after all LA92 emissions tests on a given fuel were complete. The total procedure 

consisted of the following. 

1. 5 min at 55-mph constant speed section to stabilize engine and exhaust temperatures. 

2. 1 min at 30 mph and 90 s at idle. 

3. Accelerate vehicle at WOT to a final maximum speed of 80 mph. 

4. Hold 80 mph maximum speed for a minimum of 15 s. 

5. Note: Drive cycle followed included a total of 40 s for both WOT and 80-mph hold. This 

approach met the above requirements for all vehicles tested in this program. 

6. Decelerate vehicle to 30 mph and hold for 60 s. 

7. Decelerate vehicle to 0 mph and hold for 90 s. 

8. Repeat steps 3–7 for a total of five WOT excursions to 80 mph. 

9. Repeat steps 1–8 one additional time to complete WOT protocol. 

All tests were run using EPA’s recommended vehicle test weights on simulated level ground. 

This protocol allowed for sustained WOT operation on the order of 20 to 30 s at CDPHE and slightly 

less time at ORNL and TRC due to altitude differences. 

A.2.2.2 Wide-open-throttle hill climb 

The second WOT protocol used on selected vehicles in this program was developed to allow for 

more sustained WOT operation. This expanded protocol included a 7% grade combined with the 
A-8 

vehicle’s gross combined weight rating (GCWR; i.e., maximum gross vehicle weight plus maximum 

tow weight). A grade of 7% was chosen as this represents the most aggressive sustained grade in the 

U.S. highway system (e.g., Vail pass in Colorado). The maximum gross combined vehicle weight was 

used as this load represents the worst-case, real-world condition allowable per the vehicle 

manufacturer’s recommendation. This WOT hill climb protocol was developed to more fully explore 

selected vehicles’ response to extended WOT operation and thereby more extensively determine 

ethanol effects at extreme operating conditions. Throughout hill climb testing, a single 24-in. Hartzell 

fan was used for radiator cooling (as was typical for all testing), while two additional Hartzell fans 

were oriented to circulate air under the vehicle to simulate road air cooling. Such cooling fans most 

likely circulate less air around the vehicle than a full wind tunnel but were considered sufficient based 

on exhaust component temperature observations. 

The WOT hill climb protocol started with a 5-min/50-mph warm-up cycle similar to the E-60 

protocol described previously. After this warm-up, a single WOT excursion was executed. This WOT 

excursion was intended to last for 5 min, but actual runtime was expected to be limited by vehicle 

power-to-weight ratio combined with the dynamometer speed limit of 80 mph. 

A.2.2.3 Closed-loop at high engine load 

Following the hill climb WOT procedure, a constant speed section was included to evaluate 

ethanol effects just below the engine load point where fuel enrichment occurs for hardware 

protection. A graphical description of the entire hill climb and edge of hardware protection test cycle 

is shown in Fig. A.4, including both the WOT and constant speed sections. A sample vehicle speed 

trace for one of the test vehicles is also included in Fig. A.4. 

0

10

20

30

40

50

60

70

80

90

100

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Time (Seconds)

Vehicle Speed (mph)

Drive Cycle

Vehicle Speed, 2007 Buick

5 min. @ 50 mph

 Engine Warm-up and 

Temperature 

Equalization

WOT

(300 sec)

Closed Loop at

High Engine Load

(~600 seconds)

Engine & Exhaust 

System Cooldown

Exact speed determined 

based on E0 fuel, just 

before enrichment

Fig. A.4. Wide-open-throttle (WOT) hill climb and edge of fuel enrichment drive cycle with 

vehicle speed data from 2007 Buick. 
A-9 

The actual vehicle speed used during this steady-state phase of the drive cycle was determined for 

each vehicle tested using E0 fuel and holding the maximum speed achievable before the fuel control 

went into enrichment. This phase used the same conditions, 7% grade and maximum gross combined 

vehicle weight as included in the WOT hill climb. The drive cycle of Fig. A.4 shows a duration for 

this phase of 10 min; however, actual duration was limited to that needed to achieve a stable catalyst 

temperature. Vehicles were tested on this protocol using only E0 and E20 fuels. 

A.3 NON-METHANE ORGANIC GAS CALCULATION METHOD 

The method described assumes an FID (flame ionization detector) is used for hydrocarbon (HC) 

measurement. The method could be readily adapted to Fourier transform infrared spectroscopy or 

another HC measurement method. 

A.3.1 Required Data 

Pollutant concentrations

THC: Total hydrocarbons as indicted by bench FID instrument; value in ppmC1 (parts per 

million, carbon) concentration [ppmC] 

CH4: Methane measurement from dedicated methane bench FID instrument (or equivalent); 

value in ppmC concentration [ppmC] 

C2H5OH: Ethanol content of exhaust gas, measured either by photoacoustic analyzer or impinger 

method; value in molar concentration [ppm] 

CH3CHO: Acetaldehyde measured by high-performance liquid chromatography (HPLC) or 

similar method; value in molar concentration [ppm] 

HCHO: Formaldehyde measured by HPLC or similar method; value in molar concentration 

[ppm] 

FID response factors

FID instrument response is calibrated for HC-only gas—typically propane. Because its response 

is different for oxygenated hydrocarbons and methane, its output must be corrected to account for the 

presence of these compounds in the measured exhaust. Measured response factors are determined for 

each compound known to be present and known to affect FID response. Relevant response factors for 

the current experiment are identified as follows: 

r(CH4): FID response factor to methane (generally >1). 

r(C2H5OH): FID response factor to ethanol (generally <1). 

r(CH3CHO): FID response factor to acetaldehyde (generally <1). 

The response factor for formaldehyde is not included in the above. Per CFR recommendations, 

this response factor is assumed to be zero. 

Response factors should be measured directly on the FID instrument being used for HC 

measurement. Note that FID response to ethanol may be slow due to ethanol adsorption on walls of 

supply tubing. This must be taken into account when determining FID response and when 

determining sample time for THC measurement to be certain an accurate response to ethanol is 

obtained. 

A.3.2 FID Correction 

First the FID measurement must be corrected for the presence of methane and (known) 

oxygenated hydrocarbons in the exhaust gas. This correction is typically done on a ppmC basis as 

follows. 
A-10 

Calculated NONMHC (non-oxygenated non-methane hydrocarbon)

 NONMHC = THCconc – [r(CH4) * CH4 conc] – [r(C2H5OH) * 2 * C2H5OHconc] 

 – [r(CH3CHO) * 2 * CH3CHOconc]. 

The above pollutant concentrations must be in ppmC units, hence, the factor 2 for ethanol and 

acetaldehyde. Ethanol or acetaldehyde concentrations in the above equation should be in parts per 

million on a volume (molar) basis. If impingers or DNPH cartridges were used and initial results are 

on a mass basis, they must be converted back to a parts-per-million basis for the above calculation. 

A.3.3 Non-Methane Organic Gas (NMOG) Calculation 

Oxygenated hydrocarbons are then added back to the NONMHC value to yield NMOG 

emissions. This calculation is done on a gram basis by multiplying each pollutant concentration by its 

respective density. Pollutant values are then summed, multiplied by the total volume of the sampled 

exhaust (VMIX), and normalized by the miles driven. 

 NMOG = {[NONMHCconc * NONMHCdens] + [C2H5OHconc * C2H5OHdens] 

 + [CH3CHOconc * CH3CHOdens] + [HCHOconc * HCHOdens]} 

 * 1e-6 * VMIX / miles. 

This calculation gives NMOG on a gram/mile basis. Pollutant concentrations are in parts per 

million. Again, if the initial results are on a mass-per-volume basis (as is often the case for 

acetaldehyde and formaldehyde), the calculation will have to be modified to obtain the appropriate 

units. 

Density used for NONMHC is that typically assumed for HC-only exhaust, as recommended in 

the CFR. Assuming VMIX is measured in cubic feet, the following values for pollutant densities can be 

calculated. Per CFR, calculations are based on standard temperature and pressure of 20°C (68°F) and 

1 atm. 

NONMHC: 16.33 g/ft3

 (13.88 g/mole) 

C2H5OH: 54.23 g/ft3

 (46.07 g/mole) 

CH3CHO: 51.85 g/ft3

 (44.05 g/mole) 

HCHO: 35.34 g/ft3

 (30.03 g/mole) 

CH4: 18.88 g/ft3

 (16.04 g/mole) 

A.4 RELEVANT VEHICLE EMISSIONS STANDARDS 

Emissions from vehicles have been regulated by EPA and the California Air Resources Board 

since the early 1970s. Tier 0 refers to standards that were phased-in during the 1970s as a result of the 

1970 Clean Air Act. These standards were amended in the late 1970s and first met in 1981. Tier 0 

standards were in force until 1994. Tier 1 standards were phased-in from 1994 through 1996. Table 

A.1 shows the Tier 0, Tier 1, and Low Emission Vehicle (LEV) program emissions standards. Table 

A.2 gives the footnotes (i.e., numbers in brackets [x]) for Table A.1, and Table A.3 defines the 

acronyms used in Tables A.1, A.4, and A.5. 

Phase-in of Tier 2 standards began in 2004, although some manufacturers had the option of early 

compliance under the NLEV program. Full useful life for Tier 2 vehicles is 100,000 miles, 

120,000 miles, or 150,000 miles, depending on a number of factors. The rule is described in detail in 
A-11 

the Federal Register/Vol. 65, No. 28. Tier 2 full-useful-life standards are shown in Table A.4, and 

Tier 2 50,000 mile standards are shown in Table A.5. It is important to note that these standards are 

for vehicles driven on the FTP. As such, standards are provided for reference only, vehicles tested on 

the LA92 cycle are not necessarily required to meet these standards. 

Table A.1. Federal certification exhaust emission standards for light-duty 

vehicles and light-duty trucks 

[All emissions in grams/mile on Federal Test Procedure (source: www.epa.gov/otaq/standards.htm)]
A-12 

Table A.2. Footnotes used in Table A.1 

(Source: www.epa.gov/otaq/standards.htm) 
A-13 

Table A.3. Acronyms used in Tables A.1, A.4, and A.5 

Acronym Definition 

ALVW adjusted loaded vehicle weight ([VCW+GWVR]/2) 

CFV Clean Fueled Vehicle (Program) 

CO carbon monoxide 

GVWR gross vehicle weight rating 

HCHO Formaldehyde 

HLDT heavy light-duty truck 

ILEV inherently low-emission vehicle 

LDT1 light-duty truck 1 (GVWR ≤ 6,000 lb, LVW < 3,750 lb) 

LDT2 light-duty truck 2 (GVWR ≤ 6,000 lb, 3,751 ≤ LVW ≤ 5,750 lb) 

LDT3 light-duty truck 3 (6,000 < GVWR ≤ 8,500 lb, ALVW ≤ 5,750 lb) 

LDT4 light-duty truck 4 (6,000 < GVWR ≤ 8,500 lb, 5,750 < ALVW ≤ 3,450 lb ) 

LDV light-duty vehicle (passenger car) 

LEV low-emission vehicle 

LVW loaded vehicle weight (VCW + 300 lb) 

MDPV medium-duty passenger vehicle 

NLEV National Low Emission Vehicle (Program) 

NMHC non-methane hydrocarbons 

NMOG non-methane organic gas 

NOX oxides of nitrogen 

PM particulate matter 

THC total hydrocarbons 

TLEV transitional low-emission vehicle 

ULEV ultra-low-emission vehicle 

VCW vehicle curb weight – weight of vehicle with full tanks and components included but without 

passengers or luggage (load) 

ZEV zero emission vehicle 
A-14 

Table A.4. Tier 2 and interim non-Tier 2 full-useful-life exhaust emissions standards 

[All emissions in grams/mile (source: www.epa.gov/otaq/standards.htm)] 

Table A.5. Tier 2 and interim non-Tier 2 intermediate full-useful-life (50,000 mile) 

exhaust emissions standards 

[All emissions in grams/mile (source: www.epa.gov/otaq/standards.htm)] 
B-1 

APPENDIX B 

SMALL NON-ROAD ENGINE TEST EQUIPMENT, PROCEDURES, 

AND RELEVANT EMISSIONS STANDARDS 

The equipment used during the small non-road engine (SNRE) studies can be broken down into 

the following. 

Measurement equipment

• Emissions 

• Temperatures 

Test cell equipment

• Oak Ridge National Laboratory (ORNL) 

• National Renewable Energy Laboratory (NREL) 

• Transportation Research Center (TRC) 

B.1 EMISSIONS MEASUREMENT 

All laboratories measured emissions using emissions benches equipped with conventional 

automotive emissions analyzers, such as the following: 

• heated flame ionization detector for total hydrocarbons (THC), 

• heated chemiluminescence detector for oxides of nitrogen (NOX), *

• non-dispersive infrared detectors for CO and CO2, and 

• Innova Multigas Photoacoustic Analyzer for ethanol. 

Additional details specific to each laboratory about emissions measurements are below. 

B.1.1 ORNL—Fuels, Engines, and Emissions Research Center 

Engine-out concentrations and mass rates of NOX, THC, CO, and CO2 were measured at each 

mode using a raw emissions bench and a full-flow dilution tunnel and a second tunnel bench, 

respectively. 

Brake-specific emissions were estimated by assuming a constant generator efficiency of 90%. 

The electrical load on the generator was manipulated with resistive load banks and other electrical 

appliances to approximate each load point. Current, voltage, and engine speed were manually 

recorded at each mode. Electrical load was divided by 0.9 to estimate engine brake horsepower. 

Although actual generator efficiency varies with load, measuring this efficiency was beyond the 

scope of this project. The assumption of 90% is conservative in that it tends to increase the calculated 

brake-specific emissions (assuming lower efficiency would decrease the calculated brake-specific 

emissions). Since the same efficiency was applied across all loads and all fuels, the relative change 

associated with the ethanol blends is not affected by this assumption. 

Particulate samples were collected from the full-flow tunnel for extended sampling times with the 

larger Class II engines. Total particulate sample volume was recorded with a dry gas meter, and the 

sample time for each mode was set per cycle G2 in Table B.1. 

 *

NOX measurement at NREL was by non-dispersive ultraviolet. 
B-2 

Table B.1. ISO 8178 emission test cycles 

Mode weighting factors from ISO 8178 test cycle 

Test cycle 

1 2 3 4 5 1 2 3 4 5 6 

Torque, % 100 75 50 25 10 100 75 50 25 10 0 

 Rated speed Intermediate speed Low 

idle 

G1 – – – – – 0.90 0.20 0.29 0.30 0.07 0.05 

G2 0.09 0.20 0.29 0.30 0.07 – – – – – 0.05 

G3 0.85 – – – – – – – – – 0.15 

Aldehydes were measured using dinitrophenylhydrazine- (DNPH)-treated silica gel cartridges, 

using the same sample times as those for particulates. Only the larger Class II engines were able to 

generate adequate sample for these measurements via full flow dilution. 

A microdilution tunnel with constant dilution ratio was used for dilute sampling of the Class I 

engines, such that ethanol concentration could be measured with the Innova. 

Composite emissions were computed using weighted averages of each mode, per cycle G2 in 

Table B.1. 

B.1.2 NREL—ReFUEL Laboratory 

Emissions were measured using a portable emissions measurement system (PEMS) at the 

ReFUEL laboratory. Concentrations of NOX, THC, CO, and CO2 were measured at each mode. 

Brake-specific emissions were estimated via the following engineering assumptions about power 

output and exhaust flow rate. 

• For the 2-stroke Poulan engine, a peak volumetric efficiency of 35% was assumed at full load, 

and rated power was assumed. The volumetric efficiency and brake power at idle were assumed 

to be 20% of the peak. 

• For the 4-stroke Stihl engine, the peak volumetric efficiency was assumed to be 80%, and again, 

rated power was assumed. The idle load was again assumed to be 20% of the peak, and the 

volumetric efficiency at idle was assumed to be 80% of the maximum. 

Composite emissions were computed at NREL using weighted averages of each mode, per 

cycle G3 in Table B.1 for handheld engines. 

B.1.3 TRC Full-Useful-Life (Full-Life) Study 

Mass rates of NOX, THC, CO, and CO2 were measured at each mode using a full-flow dilution 

tunnel and a tunnel bench. 

Brake-specific emissions were calculated directly from dynamometer horsepower on 

dynamometer tested engines (Class I residential power washer engines and Class IV line trimmer 

engines). 

Brake-specific engine-generator emissions were estimated by assuming a constant generator 

efficiency of 80%, based on guidance from Honda. While the actual generator efficiency is a function 

of electrical load, the load/efficiency curve was considered proprietary by Honda. Measuring this 

generator efficiency as a function of load was beyond the scope of this project and not necessary. As 

the same efficiency was applied to all modes for calculating brake-specific emissions, the relative 

change in emissions with ethanol fuel was unaffected. The electrical load on the generator was 
B-3 

manipulated with resistive load banks to approximate each load point per cycle G2 in Table B.1. 

Current, voltage, and engine speed were manually recorded at each mode. Electrical load was divided 

by 0.8 to estimate engine brake horsepower. 

Brake-specific blower engine emissions were estimated by assuming all engines made the same 

mode 1 power, measured on the dynamometer with four sacrificial engines early in the program. 

Because of engine failures associated with difficulties of dynamometer testing of the residential 

Class IV engines, the engine loads were provided by the blower wheel for the aging as well as the 

actual emissions tests. 

Particulate samples were collected from the full-flow tunnel for all engines. Total particulate 

sample volume was computed based on the sample flow rate, which was controlled by a mass flow 

controller for weighting the composite particulate matter (PM) emissions per cycle G2 in Table B.1. 

Aldehydes were measured using DNPH-treated silica gel cartridges, using the same weighting 

approach as that for particulates, controlling flow rate with a mass flow controller. 

B.2 TEMPERATURE MEASUREMENT 

During break-in and all emissions and durability testing, the following temperatures were 

recorded (as applicable). 

• Exhaust port 

• Exhaust manifold 

• Cylinder head 

• Muffler 

• Oil temperature 

• Cylinder jug 

• Exhaust outlet to atmosphere 

Type K thermocouples were used, and temperatures at all sites were recorded on computer-based 

data acquisition systems. 

B.3 TEST CELL EQUIPMENT 

B.3.1 ORNL—Fuels, Engines, and Emissions Research Center 

The following equipment was used in SNRE testing at ORNL. 

• Computer-based data acquisition system—used to record the following: 

⎯ temperature, 

⎯ fuel:air equivalence ratio, 

⎯ gravimetric fuel mass, and 

⎯ emissions data. 

• Inductive Tachometer (Tiny Tach)—Used to measure engine speed when available. Engine speed 

was recorded manually on a log sheet. 

• Generator load was provided by resistive load banks and augmented when necessary by electrical 

appliances. Electrical load (volts and amps) was recorded manually on a log sheet. 

B.3.2 NREL—ReFUEL Laboratory 

The following equipment was used in testing emissions and temperature at the ReFUEL 

Laboratory. 
B-4 

• Computer-based data acquisition system—used to record the following: 

⎯ temperature and 

⎯ engine speed data. 

• Semtech PEMS—used for measuring exhaust concentrations of HC, CO, and NOX. 

B.3.3 TRC Full-Life Study 

The TRC emissions laboratory is equipped with two SNRE dynamometers, sized for Class I and 

Class IV engines. Full-flow dilution was used for measuring emissions, as described above. 

Additional hardware for extended aging operations includes computer-controlled aging stands. 

Specifics of equipment used for each engine follow. 

• Briggs and Stratton power washer engines

⎯ Emissions were measured on the dynamometer according to CFR guidelines. Two protocols 

were used and will be described in more detail in Sect. C.4. 

⎯ Engines were aged using the power washer to provide the aging load by use of a closed-loop 

water system. Spray wands were held in a special fixture and a computer-controlled 

pneumatic actuator activated the spray trigger using a 2-mode cycle. 

• Stihl line trimmer engines

⎯ Engines were emissions tested on the dynamometer according to CFR guidelines. Stihl 

engineers provided a special dynamometer fixture to facilitate testing on the dynamometer. 

⎯ Engines were aged with the line guard removed and the line extended to create additional 

windage loads. Line length was adjusted so that the engines would run at 8,000 RPM in 

mode 1. A computer-controlled pneumatic actuator was used to cycle the throttle trigger 

during the aging program. 

• Weed Eater leaf blowers—were initially tested on the dynamometer, but this resulted in 

catastrophic engine failures due to the lack of an appropriate Class IV-engine-test fixture for this 

engine. Average mode 1 power measurements on the initial four engines were used to estimate 

blower power for all subsequent engine tests. The blower wheel was used as the engine brake for 

both the aging load and the emissions testing. A computer-controlled pneumatic actuator was 

used to cycle the throttle trigger during the aging program. 

• Honda generators—used an electrical load bank for the aging load as well as for emulating the 

6-mode emissions test. The same load bank was used for emissions testing of all four generators, 

but each generator had a dedicated load bank during aging. A computer-driven control system 

switched loads on the load banks automatically so that each mode was held for the appropriate 

time duration for the entirety of the aging protocol. 

B.4 TEST PROCEDURES 

Engines at all sites were instrumented with thermocouples. Engine break-in was conducted using 

E0 (federal certification gasoline). The new engines were run at moderate load for 40 min to 10 hr 

(nominally 1–4% of full-life) before the first emissions tests were conducted. None of the engine 

manuals specified a break-in time or procedure. 

B.4.1 Testing at ORNL 

The basic procedure for emissions testing at ORNL was as follows. 

1. Engine instrumentation and preparation

Each engine was instrumented for temperature with thermocouples. In addition, a wide-range 

universal exhaust gas oxygen sensor was installed in the muffler to measure the fuel:air equivalence 
B-5 

ratio, and a sample port was installed in the exhaust manifold for monitoring engine-out emissions 

concentrations. Most of the engines were instrumented for engine speed using an inductive-spark 

pickup tachometer. 

2. Engine break-in 

Break-in was conducted at moderate load or on the appropriate emissions test cycle for 2 hr. 

Exceptions were the field-aged Honda generator (no break-in needed) and the Kohler generator, 

which was subjected to a 10-hr break-in given its 1,000-hr full life.

3. Emissions testing 

The 6-mode gaseous emissions test (G2 procedure from Table B.1) used the following process. 

1. Warm engine at 50% load for 20 min. 

2. Switch to mode 1. Stabilize engine for 10 min, then collect data for 10 min. 

3. Repeat step 2 for modes 2–6. 

4. Switch to E20 (or E10 or E15); repeat steps 1–3. 

5. Repeat E0 test at end. 

For full-flow tunnel sampling of PM and aldehydes, each mode was timed according to the 

6-mode weighting factors. To collect adequate PM mass, 3,000-s and 6,000-s total sampling times 

were used. Each mode change was followed by 10 min of stabilization. Mode sample times are listed 

below. 

• Mode 1 (9% of 6,000) for 540 s. 

• Mode 2 (20%) for 1,200 s. 

• Mode 3 (29%) for 1,740 s. 

• Mode 4 (30%) for 1,800 s. 

• Mode 5 (7%) for 420 s. 

• Mode 6 (5%) for 300 s. 

B.4.2 Testing at NREL 

The basic procedure for emissions testing at NREL was as follows. 

1. Engine instrumentation and preparation

Each engine was instrumented for temperature with thermocouples. In addition, each engine was 

instrumented for engine speed and operating time (hour meter). Time of operation on each fuel and 

each test cycle was recorded. 

2. Engine break-in

Break-in was conducted by running the appropriate 2-mode cycle for 40 min. 

3. Emissions testing

The basic emissions testing procedure at NREL was as follows. 

• Operate on aging cycle for a minimum of 40 min to stabilize engine. 

• Perform emissions certification cycle, in duplicate. 

• Change fuel to ethanol blend (E10, E15, or E20), being sure to drain tank and fuel lines 

completely. 

• Repeat emissions testing per the above protocol for each fuel blend (E10, E15, E20). 
B-6 

NREL also tested the Poulan blower to full life after testing E0, E10, E15, and E20 for a total of 

about 12 hr. The aging cycle at NREL with the Poulan blower was as follows. 

• Operate on aging cycle for 8 hr on each fuel, starting with E0. 

• Record temperatures and speed and note operation. 

• Return to E0. 

B.4.3 Testing at TRC—Full-Life Testing of Class I and Class IV Engines 

Initially, four of each type of equipment were to be tested. Following baseline emissions 

measurement on each engine with E0, one engine of each type was then dedicated to one of four fuels 

(E0, E10, E15, or E20) for aging. However, due to the inherent engine-to-engine differences in the 

residential engines, more than four engines were baselined in an attempt to evaluate four similar 

engines in the aging program. Six power washer engines and eight Weed Eater leaf blowers were 

baselined. Table B.2 provides details on the engines and fuels tested at TRC. 

General procedure. The general approach for each four-engine, four-fuel combination at TRC 

was as follows.

1. Engine instrumentation—Engines at TRC were instrumented for numerous temperatures with 

thermocouples. 

2. Break-in for 2 hr (E0 fuel, all engines). 

3. Applicable emissions certification cycle (3–4 consecutive tests, E0 fuel, all engines). 

4. Fuel switch, dedicated ethanol blend fuel per engine (3 engines). 

5. Applicable emissions certification cycle (3–4 consecutive tests, dedicated ethanol blend fuel per 

engine). 

6. Durability cycle for half of full life, dedicated ethanol blend fuel.*

7. Applicable emissions certification cycle, dedicated ethanol blend fuel (3–4 consecutive tests). 

8. Durability cycle for remainder of full life, dedicated ethanol blend fuel. 

9. Applicable emissions certification cycle, dedicated ethanol blend fuel (3–4 consecutive tests). 

10. Fuel switch (three engines back to E0), applicable emissions certification cycle (3–4 consecutive 

tests, E0 fuel). 

Engine oil for the pressure washers and generators was changed per manufacturer’s recommendations. Samples of each oil drain were stored for potential future analysis. 

B.4.4 Specific Test Protocols in Full-Life Study 

Table B.2 provides additional detail on the specific test protocols for each engine in the full-life 

study. 

B.4.4.1 Briggs and Stratton Quattro engine (Troy-Bilt power washer, Class I residential, 

125-hr life) 

The power washer engines were aged using a 2-mode test. This approach was used such that all 

four engines could be aged simultaneously using the power washer as the engine load, and it was 

deemed similar to actual field use of this machine. 

 *

For the engines that survived the full-useful-life (full-life) durability test (50–500 hr, depending on engine type and 

application), the emissions test protocol was repeated at half-life and again at full-life hours. Full-life tests were conducted 

first on the respective fuel for each engine, followed by a final E0 test. 
B-7 

Table B.2. Summary of engine, fuel, and emissions test protocols for full-useful-life (full-life) testing 

[Hashed areas indicate no data collected. Ethanol blend denotes fuel tested 

at that condition (E0, E10, E15, or E20)] 

Newa

 Full life 

Engine/equipment 

(emissions test protocol) E0 baseline Ethanol 

blend 

Half life Ethanol 

blend Baseline 

PW1 E0 E0 E0 E0 E0 

PW2 E0 E10 E10 E10 E0 

PW3 E0 E15 E15 E15 E0 

PW4 E0 E20 E20 E20 E0 

PW5 E0 

Briggs and 

Stratton power 

washer (6-mode 

dyno test, TRC 

Protocol)b

PW6 E0 

PW1 E0 E0 

PW2 E10 E0 

PW3 E15 E0 

PW4 E20 E0 

PW5 E0 

Briggs and 

Stratton power 

washer (6-mode 

dyno test, BASCO 

Protocol)c

PW6 

G1 E0 E0 E0 E0 E0 

G2 E0 E10 E10 E10 E0 

G3 E0 E15 E15 E15 E0 

Honda generator

(6-mode test, 

generator as engine 

brake) G4 E0 E20 E20 E20 E0 

B2d,e E0 E0 E0 

B5d E0 E10 E10 E10 E0 

B7d,f E0 E15

B3f,g E0 E15

B8d,h E0 E20h

B6i E0 E20 E20 E20 E0 

B1 E0 

Weed Eater blower

(2-mode test, 

blower wheel as 

engine brake) 

B4 E0 

T1 E0 E0 E0 E0 E0 

T2 E0 E10 E10 E10 E0 

T3 E0 E15 E15 E15 E0 

Stihl Line 

Trimmer (2-mode 

dyno test) T4 E0 E20 E20 E20 E0 

a

New refers to engines following 2 hr initial break-in. b

TRC protocol allowed engine to run on governor in mode 1, similar to power washer operation in spray mode. c

BASCO protocol involved override of governor for wide-open throttle operation in mode 1. Because BASCO 

protocol not initially run on PW1-PW4 in new condition, PW5 tested on BASCO protocol for new engine 

comparison. PW5 failed during E10 testing on BASCO protocol. d

Engine initially selected for aging program (B2-E0, B5-E10, B7-E15, B8-E20). e

B2 failed before full life (50 hr). 

f Failed before half life. 

g

B3 replaced B7 as E15 engine after B7 failure. 

h

No E20 emissions data obtained from B8 (would not idle). i

B6 replaced B8 as E20 engine when B8 would not idle on E20. 
B-8 

TRC protocol. Emissions tests on the power washer engines were conducted using the TRC 

protocol at the new, half-life, and full-life condition. The TRC protocol is a 6-mode emissions test 

and was conducted on the engine dynamometer per CFR guidelines. The mode 1 load was determined 

using the installed governor to control engine speed, and dynamometer load was set to match the 

observed engine speed when the power washer was in spray mode on the aging stand. 

BASCO protocol. Briggs and Stratton Company (BASCO) was consulted on the proper protocol 

for testing this Class I engine and provided guidance that the correct mode 1 load should be 

determined by physically overriding the governor and fixing the throttle in the full-open position. 

Because this information was obtained after the initial baseline and start of the aging process, it was 

decided to run this revised 6-mode protocol (named BASCO protocol) at the end of the aging 

program and to continue using the TRC protocol, still a representative test because it could be 

considered a measure of in-use emissions. As presented in Table B.2, PW1–PW4 were tested on the 

TRC protocol at the new, half-life, and full-life conditions but only tested on the BASCO protocol at 

the full-life condition. 

To obtain reference emissions on a new engine with the BASCO protocol, PW5 was retested at 

the end of the program. The initial intent of this program modification was to test PW5 on both the 

TRC and BASCO protocols using all four fuels; however, during the E10 testing, the engine began to 

run very erratically. Reasons for the engine problem are unknown. 

Power washer aging and emissions general procedure. 

1. Engine break-in 

• 2-mode 85/15. 

• 10-min cycle. 

• 2 hr. 

2. Baseline emissions test (dyno)—TRC protocol 

• 20-min warm-up at wide-open throttle (WOT). 

• 6-mode test—5-min stabilization with 1-min sampling. 

• E0 and ethanol blend fuels. 

3. Aging (power washer) 

• 2-mode 85/15. 

• 10-min cycle. 

4. Half-life emissions test (dyno)—TRC protocol

• 20-min warm-up at WOT. 

• 6-mode test—5-min stabilization with 1-min sampling. 

• Ethanol blend fuels. 

5. Aging (power washer) 

• 2-mode 85/15. 

• 10-min cycle. 

6. Full-life emissions test (dyno)—TRC and BASCO protocols

• 20-min warm-up at WOT. 

• 6-mode test—5-min stabilization with 1-min sampling. 

• E0 and ethanol blend fuels. 
B-9 

B.4.4.2 Honda EB 3000c generator test protocols—(GX200 Class I Commercial, 500 H life) 

Honda test procedure. Following 2 hr of E0 break-in (using the 6-mode test) on the load bank 

aging stand, the four engines were baseline emissions tested on E0, using a simulated 6-mode test in 

which the electrical load was selected to closely match the six desired engine modes. Denoted 

G1–G4, (generator 1–generator 4), the units were assigned one of the four fuels tested (E0, E10, E15, 

E20) as presented in Table B.2. 

Honda test protocol. 

1. Break-in—mode 3 for 2 hr. 

2. Baseline emissions test—10-min warm-up at mode 1, 6-mode test, 10 min at each mode, 1-min 

sample. E0 and ethanol blend fuels. 

3. Aging—6-mode operation, time at each mode per EPA weighting, 1-hr cycle time. 

4. Half-life emissions test—10-min warm-up at mode 1, 6-mode test, 10 min at each mode, 1-min 

sample. Ethanol blend fuels. 

5. Aging—6-mode operation, time at each mode per EPA weighting, 1-hr cycle time. 

6. Full-life emissions test—10-min warm-up at mode 1, 6-mode test, 10 min at each mode, 1-min 

sample. E0 and ethanol blend fuels. 

B.4.4.3 Weed Eater Featherlite leaf blower protocol—(Class IV Residential, 50 H life) 

Initial attempts to test the blower engines on the dynamometer were unsuccessful. Through 

industry consultation it was learned that a special engine-specific dynamometer fixture for Class IV 

engines is necessary to avoid catastrophic engine failures. Tests of four blowers did provide a 

reasonable estimate of actual shaft horsepower for this engine type, and this measurement was used in 

calculating brake-specific emissions when the replacement blowers were emissions tested. Emissions 

tests used the blower wheel as the engine brake, similar to the aging stand. 

Weed Eater test protocol. 

1. Break-in 

• 2-mode 85/15. 

• 6-min cycle, 2 hr. 

• Baseline emissions test—Eight leaf blowers, denoted B1–B8, were baselined on E0, and then 

four were selected for the aging program (B2, B5, B7, and B8). 

⎯ 8-min warm-up at WOT. 

⎯ 85/15 2-mode test (6-min cycle). 

2. Aging 

• 2-mode 85/15. 

• 6-min cycle. 

3. Half-life emissions test 

• 8-min warm-up at WOT. 

• 85/15 2-mode test (6-min cycle). 

4. Aging

• 2-mode 85/15. 

• 6-min cycle. 

5. Full-life emissions test 

• 8-min warm-up at WOT. 

• 85/15 2-mode test (6-min cycle). 
B-10 

B.4.4.4 Stihl line trimmer protocol—(Class IV Commercial, 300 H life) 

Denoted T1–T4 (trimmer 1–trimmer 4), the units were assigned one of the four fuels tested (E0, 

E10, E15, E20) as presented in Table B.2. Stihl provided a proprietary dynamometer fixture to 

facilitate proper dynamometer emissions tests on these engines that would avoid the failures 

experienced with the leaf blower engines. After baseline testing of all four engines with E0 and the 

other three engines with their respective ethanol blends, the engines were aged on the aging stand 

using the extended line windage as a brake. The trimmer guards were removed and trimmer line 

length was adjusted to achieve the desired 8,000 RPM engine speed at full load. At half life (150 hr) 

the engines were emissions tested on the dynamometer with only their respective ethanol blends, then 

returned to the aging stand to accumulate 300 hr. End-of-life emissions tests were conducted on the 

ethanol blend, then each of the three dedicated ethanol blend engines was retested with E0. All four 

engines survived the aging protocol and were able to be emissions tested at each interval. 

Stihl protocol. 

1. Break-in (trimmer stand)—2-mode 85/15, 6-min cycle, 2 hr. 

2. Baseline emissions test (dyno)—8-min warm-up at WOT, 85/15 2-mode test (5 min per mode, 1-

min sample). 

3. Aging (trimmer stand)—2-mode 85/15, 6-min cycle, 2 hr. 

4. Half-life emissions test (dyno)—8-min warm-up at WOT, 85/15 2-mode test (6-min cycle). 

5. Aging (dyno)—2-mode 85/15, 6-min cycle. 

6. Full-life emissions test (dyno)—8-min warm-up at WOT, 2-mode 85/15 (5 min per mode, 1-min 

sample). 

B.5 RELEVANT SNRE EMISSIONS STANDARDS 

Emissions from small non-road engines (SNREs) [i.e., engines at or below 19 kW (~25 hp)] are 

regulated by EPA according to application, size, and useful life rating. Table B.3 shows Phase 1 and 

Phase 2 standards for SNREs used in non-handheld applications (Class I, Class II, Class I-A and 

Class I-B). Table B.4 shows the Phase 1 and Phase 2 standards for SNREs used in handheld 

applications (Class III, Class IV, and Class V). In September 2008, EPA finalized new rules for these 

classes of engines. The new rules include the first evaporative emission standards for both 

non-handheld and handheld applications. The new rules also include Phase 3 exhaust emission 

standards for SNREs used in non-handheld applications. Most of the new standards take effect in 

2011 or 2012. The new standards are not provided here but can be reviewed at 

www.epa.gov/otaq/equip-ld.htm. 

Table B.3. Phase 1 and Phase 2 non-handheld engine emission standards 

Phase Class Displacement 

(cc) Model year HC + NOX

(g/kW-hr) 

CO 

(g/kW-hr) 

1 I <225 1997 16.1 519 

II ≥225 1997 13.4 519 

I-A <66 2001 50 610 

I-B 66 ≤ cc < 100 2001 40 610 

I 100 ≤ cc < 225 August 2007a 16.1 610 

2 

II cc ≥ 225 2001 

2002 

2003 

2004 

2005 

18.0 

16.6 

15.0 

13.6 

12.1 

610 

a

Effective date. If a new engine family was introduced after August 1, 2003, it was required to meet the Phase 2 

standards at that time. 
B-11 

Table B.4. Phase 1 and Phase 2 handheld engine emission standards 

Phase Class Displacement 

(cc) 

Model 

Year 

HC 

(g/kW-hr) 

NOX 

(g/kW-hr) 

CO 

(g/kW-hr) 

III <20 2001 295 5.36 805 

IV 20 ≤ cc <5 0 2001 241 5.36 805 

1 

V ≥50 2001 161 5.36 603 

HC + NOX

(g/kW-hr) 

CO 

(g/kW-hr) 

III <20 2002 

2003 

2004 

2005 

238 

175 

113 

50 

805 

IV 20 ≤ cc <5 0 2002 

2003 

2004 

2005 

196 

148 

99 

50 

805 

2 

V ≥50 2004 

2005 

2006 

2007 

143 

119 

96 

72 

603 

For the Phase 1 standards, manufacturers were required to demonstrate compliance when the 

engines were new. Beginning with the Phase 2 standards, manufacturers must demonstrate 

compliance over a full-useful-life period. Manufacturers are required to select the full-useful-life 

period (from those specified in Table B.5) that most closely approximates the useful lives of the 

equipment into which the engines are to be installed. 

Table B.5. Full useful life periods for Phase 2 SNREs 

Application Class Displacement

(cc) 

Low-hour 

period 

Medium-hour 

period 

High-hour 

period 

I-A <66 50 125 300 

I-B 66 ≤ cc < 100 125 250 500 

I 100 ≤ cc < 225 125 250 500 

Non-handheld 

II cc ≥ 225 250 500 1,000 

III <20 50 125 300 

IV 20 ≤ cc < 50 50 125 300 

Handheld 

V ≥50 50 125 300 

C-1 

APPENDIX C 

INDIVIDUAL VEHICLE EMISSIONS RESULTS 

Figures in this appendix show the average emissions from each vehicle tested. (Table C.1 is a 

listing of the vehicles, figure numbers, and other pertinent information.) Figure C.1 shows the nonmethane organic gas (NMOG), non-methane hydrocarbons (NMHC), carbon monoxide (CO), oxides 

of nitrogen (NOX), and fuel economy (FE) for the 2007 Chrysler Town and Country, while Fig. C.2 

shows the ethanol, acetaldehyde, and formaldehyde emissions for the same vehicle. Similarly, for the 

remaining vehicles, the odd-numbered figures show the NMOG, NHMC, CO, NOX, and FE, while the 

even-numbered figures show the ethanol, acetaldehyde, and formaldehyde. In all figures, CO 

emissions are divided by 10 and FE is divided by 100 to permit plotting on a common axis with the 

other emissions. All results are the average of at least 3 composite LA92 results at 75°F. 

Table C.1. List of Appendix C figures 

Figure 

numbers 

OEM 

(make) Model Year Test site 

C.1–C.2 Chrysler Town & Country 2007 NREL/CDPHE 

C.3–C.4 Ford F150 2007 TRC 

C.5–C.6 Ford F150 2003 TRC 

C.7–C.8 Ford Taurus 2003 TRC 

C.9–C.10 GM (Buick) Lucerne 2007 NREL/CDPHE 

C.11–C.12 GM (Buick) LeSabre 2003 NREL/CDPHE 

C.13–C.14 GM Silverado 2007 TRC 

C.15–C.16 Honda Accord 2007 TRC 

C.17–C.18 Nissan Altima 2003 TRC 

C.19–C.20 Toyota Camry 2007 ORNL 

C.21–C.22 Toyota Camry 2003 ORNL 

C.23–C.24 Chrysler PT Cruiser 2001 NREL/CDPHE 

C.25–C.26 Ford Crown Victoria 1999 NREL/CDPHE 

C.27–C.28 Honda Civic 1999 ORNL 

C.29–C.30 Toyota Corolla 1999 NREL/CDPHE 

C.31–C.32 VW Golf GTI 2004 ORNL 

Abbreviations: OEM = original equipment manufacturer, NREL = National Renewable Energy 

Laboratory, CDPHE = Colorado Department of Public Health and Environment, TRC = Transportation 

Research Center, ORNL = Oak Ridge National Laboratory. 
C-2 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

NMOG NMHC CO / 10 NOx FE / 100

Emissions or Fuel Economy (g/mile or mpg)

LA92 Test Cycle

2007 Chrysler T&C: Tier 2, Bin 5

Fig. C.1. Non-methane organic gas (NMOG), non-methane hydrocarbons (NMHC), 

carbon monoxide (CO), oxides of nitrogen (NOX), and fuel economy (FE) for 2007 

Chrysler Town and Country on LA92 cycle. Bars show average of 3 tests at 75°F. 

0.00

0.25

0.50

0.75

1.00

1.25

1.50

1.75

E0 E10 E15 E20 E0 E10 E15 E20 E0 E10 E15 E20

Ethanol ( /10) Acetaldehyde Formaldehyde

Ethanol or Aldehyde Emissions (mg/mile)

LA92 Test Cycle

2007 Chrysler T&C: Tier 2, Bin 5

Fig. C.2. Ethanol, acetaldehyde, and formaldehyde emissions for 2007 Chrysler 

Town and Country on LA92 cycle. Bars show average of 3 tests at 75°F. 
C-3 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

NMOG NMHC CO / 10 NOx FE / 100

Emissions or Fuel Economy (g/mile or mpg)

LA92 Test Cycle

2007 Ford F150: Tier 2, Bin 8

Fig. C.3. Non-methane organic gas (NMOG), non-methane hydrocarbons (NMHC), 

carbon monoxide (CO), oxides of nitrogen (NOX), and fuel economy (FE) for 2007 Ford 

F150 on LA92 cycle. Bars show average of 3 tests at 75°F. 

0.00

0.25

0.50

0.75

1.00

1.25

1.50

1.75

E0 E10 E15 E20 E0 E10 E15 E20 E0 E10 E15 E20

Ethanol ( /10) Acetaldehyde Formaldehyde

Ethanol or Aldehyde Emissions (mg/mile)

LA92 Test Cycle

2007 Ford F150: Tier 2, Bin 8

Fig. C.4. Ethanol, acetaldehyde, and formaldehyde emissions for 2007 Ford F150 on 

LA92 cycle. Bars show average of 3 tests at 75°F. 
C-4 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

NMOG NMHC CO / 10 NOx FE / 100

Emissions or Fuel Economy (g/mile or mpg)

LA92 Test Cycle

2003 Ford F150: Tier 1 (LEV)

Fig. C.5. Non-methane organic gas (NMOG), non-methane hydrocarbons (NMHC), 

carbon monoxide (CO), oxides of nitrogen (NOX), and fuel economy (FE) for 2003 Ford 

F150 on LA92 cycle. Bars show average of 3 tests at 75°F. 

0.00

0.25

0.50

0.75

1.00

1.25

1.50

1.75

E0 E10 E15 E20 E0 E10 E15 E20 E0 E10 E15 E20

Ethanol ( /10) Acetaldehyde Formaldehyde

Ethanol or Aldehyde Emissions (mg/mile)

LA92 Test Cycle

2003 Ford F150: Tier 1 (LEV)

Fig. C.6. Ethanol, acetaldehyde, and formaldehyde emissions for 2003 Ford F150 

on LA92 cycle. Bars show average of 3 tests at 75°F. 
C-5 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

NMOG NMHC CO / 10 NOx FE / 100

Emissions or Fuel Economy (g/mile or mpg)

LA92 Test Cycle

2003 Ford Taurus: Tier 2, Bin 8

Fig. C.7. Non-methane organic gas (NMOG), non-methane hydrocarbons (NMHC), carbon 

monoxide (CO), oxides of nitrogen (NOX), and fuel economy (FE) for 2003 Ford Taurus on LA92 

cycle. Bars show average of 3 tests at 75°F. 

0.00

0.25

0.50

0.75

1.00

1.25

1.50

1.75

E0 E10 E15 E20 E0 E10 E15 E20 E0 E10 E15 E20

Ethanol ( /10) Acetaldehyde Formaldehyde

Ethanol or Aldehyde Emissions (mg/mile)

LA92 Test Cycle

2003 Ford Taurus: Tier 2, Bin 8

Fig. C.8. Ethanol, acetaldehyde, and formaldehyde emissions for 2003 Ford Taurus 

on LA92 cycle. Bars show average of 3 tests at 75°F. 
C-6 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

NMOG NMHC CO / 10 NOx FE / 100

Emissions or Fuel Economy (g/mile or mpg)

LA92 Test Cycle

2007 Buick Lucerne: Tier 2, Bin 5

Fig. C.9. Non-methane organic gas (NMOG), non-methane hydrocarbons (NMHC), 

carbon monoxide (CO), oxides of nitrogen (NOX), and fuel economy (FE) for 2007 Buick 

Lucerne on LA92 cycle. Bars show average of 3 tests at 75°F. 

0.00

0.25

0.50

0.75

1.00

1.25

1.50

1.75

E0 E10 E15 E20 E0 E10 E15 E20 E0 E10 E15 E20

Ethanol ( /10) Acetaldehyde Formaldehyde

Ethanol or Aldehyde Emissions (mg/mile)

LA92 Test Cycle

2007 Buick Lucerne: Tier 2, Bin 5

Fig. C.10. Ethanol, acetaldehyde, and formaldehyde emissions for 2007 Buick Lucerne 

on LA92 cycle. Bars show average of 3 tests at 75°F. 
C-7 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

NMOG NMHC CO / 10 NOx FE / 100

Emissions or Fuel Economy (g/mile or mpg)

LA92 Test Cycle

2003 Buick LeSabre: Tier 2, Bin 8

Fig. C.11. Non-methane organic gas (NMOG), non-methane hydrocarbons (NMHC), 

carbon monoxide (CO), oxides of nitrogen (NOX), and fuel economy (FE) for 2003 Buick 

LeSabre on LA92 cycle. Bars show average of 3 tests at 75°F. 

0.00

0.25

0.50

0.75

1.00

1.25

1.50

1.75

E0 E10 E15 E20 E0 E10 E15 E20 E0 E10 E15 E20

Ethanol ( /10) Acetaldehyde Formaldehyde

Ethanol or Aldehyde Emissions (mg/mile)

LA92 Test Cycle

2003 Buick LeSabre: Tier 2, Bin 8

Fig. C.12. Ethanol, acetaldehyde, and formaldehyde emissions for 2003 Buick LeSabre 

on LA92 cycle. Bars show average of 3 tests at 75°F. 
C-8 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

NMOG NMHC CO / 10 NOx FE / 100

Emissions or Fuel Economy (g/mile or mpg)

LA92 Test Cycle

2007 Chevrolet Silverado: Tier 2, Bin 8

Fig. C.13. Non-methane organic gas (NMOG), non-methane hydrocarbons (NMHC), 

carbon monoxide (CO), oxides of nitrogen (NOX), and fuel economy (FE) for 2007 

Chevrolet Silverado on LA92 cycle. Bars show average of 3 tests at 75°F. 

0.00

0.25

0.50

0.75

1.00

1.25

1.50

1.75

E0 E10 E15 E20 E0 E10 E15 E20 E0 E10 E15 E20

Ethanol ( /10) Acetaldehyde Formaldehyde

Ethanol or Aldehyde Emissions (mg/mile)

LA92 Test Cycle

2007 Chevrolet Silverado: Tier 2, Bin 8

Fig. C.14. Ethanol, acetaldehyde, and formaldehyde emissions for 2007 Chevrolet 

Silverado on LA92 cycle. Bars show average of 3 tests at 75°F. 
C-9 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

NMOG NMHC CO / 10 NOx FE / 100

Emissions or Fuel Economy (g/mile or mpg)

LA92 Test Cycle

2007 Honda Accord: Tier 2, Bin 5

Fig. C.15. Non-methane organic gas (NMOG), non-methane hydrocarbons (NMHC), 

carbon monoxide (CO), oxides of nitrogen (NOX), and fuel economy (FE) for 2007 Honda 

Accord on LA92 cycle. Bars show average of 3 tests at 75°F. 

0.00

0.25

0.50

0.75

1.00

1.25

1.50

1.75

E0 E10 E15 E20 E0 E10 E15 E20 E0 E10 E15 E20

Ethanol ( /10) Acetaldehyde Formaldehyde

Ethanol or Aldehyde Emissions (mg/mile)

LA92 Test Cycle

2007 Honda Accord: Tier 2, Bin 5

Fig. C.16. Ethanol, acetaldehyde, and formaldehyde emissions for 2007 Honda Accord 

on LA92 cycle. Bars show average of 3 tests at 75°F. 
C-10 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

NMOG NMHC CO / 10 NOx FE / 100

Emissions or Fuel Economy (g/mile or mpg)

LA92 Test Cycle

2003 Nissan Altima: LEV

Fig. C.17. Non-methane organic gas (NMOG), non-methane hydrocarbons (NMHC), 

carbon monoxide (CO), oxides of nitrogen (NOX), and fuel economy (FE) for 2003 Nissan 

Altima on LA92 cycle. Bars show average of 3 tests at 75°F. 

0.00

0.25

0.50

0.75

1.00

1.25

1.50

1.75

E0 E10 E15 E20 E0 E10 E15 E20 E0 E10 E15 E20

Ethanol ( /10) Acetaldehyde Formaldehyde

Ethanol or Aldehyde Emissions (mg/mile)

LA92 Test Cycle

2003 Nissan Altima: LEV

Fig. C.18. Ethanol, acetaldehyde, and formaldehyde emissions for 2003 Nissan Altima 

on LA92 cycle. Bars show average of 3 tests at 75°F. 
C-11 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

NMOG NMHC CO / 10 NOx FE / 100

Emissions or Fuel Economy (g/mile or mpg)

LA92 Test Cycle

2007 Toyota Camry: Tier 2, Bin 5

Fig. C.19. Non-methane organic gas (NMOG), non-methane hydrocarbons (NMHC), 

carbon monoxide (CO), oxides of nitrogen (NOX), and fuel economy (FE) for 2007 Toyota 

Camry on LA92 cycle. Bars show average of 3 tests at 75°F. 

0.00

0.25

0.50

0.75

1.00

1.25

1.50

1.75

E0 E10 E15 E20 E0 E10 E15 E20 E0 E10 E15 E20

Ethanol ( /10) Acetaldehyde Formaldehyde

Ethanol or Aldehyde Emissions (mg/mile)

LA92 Test Cycle

2007 Toyota Camry: Tier 2, Bin 5

Fig. C.20. Ethanol, acetaldehyde, and formaldehyde emissions for 2007 Toyota Camry on 

LA92 cycle. Bars show average of 3 tests at 75°F. 
C-12 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

NMOG NMHC CO / 10 NOx FE / 100

Emissions or Fuel Economy (g/mile or mpg)

LA92 Test Cycle

2003 Toyota Camry: ULEV

Fig. C.21. Non-methane organic gas (NMOG), non-methane hydrocarbons (NMHC), 

carbon monoxide (CO), oxides of nitrogen (NOX), and fuel economy (FE) for 2003 Toyota 

Camry on LA92 cycle. Bars show average of 3 tests at 75°F. 

0.00

0.25

0.50

0.75

1.00

1.25

1.50

1.75

E0 E10 E15 E20 E0 E10 E15 E20 E0 E10 E15 E20

Ethanol ( /10) Acetaldehyde Formaldehyde

Ethanol or Aldehyde Emissions (mg/mile)

LA92 Test Cycle

2003 Toyota Camry: ULEV

Fig. C.22. Ethanol, acetaldehyde, and formaldehyde emissions for 2003 Toyota Camry on 

LA92 cycle. Bars show average of 3 tests at 75°F. 
C-13 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

NMOG NMHC CO / 10 NOx FE / 100

Emissions or Fuel Economy (g/mile or mpg)

LA92 Test Cycle

2001 Chrysler PT Cruiser: NLEV

Fig. C.23. Non-methane organic gas (NMOG), non-methane hydrocarbons 

(NMHC), carbon monoxide (CO), oxides of nitrogen (NOX), and fuel economy (FE) for 

2001 Chrysler PT Cruiser on LA92 cycle. Bars show average of 3 tests at 75°F. 

0.00

0.25

0.50

0.75

1.00

1.25

1.50

1.75

E0 E10 E15 E20 E0 E10 E15 E20 E0 E10 E15 E20

Ethanol ( /10) Acetaldehyde Formaldehyde

Ethanol or Aldehyde Emissions (mg/mile)

LA92 Test Cycle

2001 Chrysler PT Cruiser: NLEV

Fig. C.24. Ethanol, acetaldehyde, and formaldehyde emissions for 2001 Chrysler PT 

Cruiser on LA92 cycle. Bars show average of 3 tests at 75°F. 
C-14 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

NMOG NMHC CO / 10 NOx FE / 100

Emissions or Fuel Economy (g/mile or mpg)

LA92 Test Cycle

1999 Ford Crown Victoria: ULEV

Fig. C.25. Non-methane organic gas (NMOG), non-methane hydrocarbons (NMHC), carbon 

monoxide (CO), oxides of nitrogen (NOX), and fuel economy (FE) for 1999 Ford Crown Victoria on 

LA92 cycle. Bars show average of 3 tests at 75°F. 

0.00

1.00

2.00

3.00

4.00

5.00

6.00

E0 E10 E15 E20 E0 E10 E15 E20 E0 E10 E15 E20

Ethanol ( /10) Acetaldehyde Formaldehyde

Ethanol or Aldehyde Emissions (mg/mile)

LA92 Test Cycle

1999 Ford Crown Victoria: ULEV

Fig. C.26. Ethanol, acetaldehyde, and formaldehyde emissions for 1999 Ford Crown 

Victoria on LA92 cycle. Bars show average of 3 tests at 75°F. 
C-15 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

NMOG NMHC CO / 10 NOx FE / 100

Emissions or Fuel Economy (g/mile or mpg)

LA92 Test Cycle

1999 Honda Civic: Tier 1

Fig. C.27. Non-methane organic gas (NMOG), non-methane hydrocarbons (NMHC), 

carbon monoxide (CO), oxides of nitrogen (NOX), and fuel economy (FE) for 1999 Honda 

Civic on LA92 cycle. Bars show average of 3 tests at 75°F. 

0.00

0.25

0.50

0.75

1.00

1.25

1.50

1.75

E0 E10 E15 E20 E0 E10 E15 E20 E0 E10 E15 E20

Ethanol ( /10) Acetaldehyde Formaldehyde

Ethanol or Aldehyde Emissions (mg/mile)

LA92 Test Cycle

1999 Honda Civic: Tier 1

Fig. C.28. Ethanol, acetaldehyde, and formaldehyde emissions for 1999 Honda Civic 

on LA92 cycle. Bars show average of 3 tests at 75°F. 
C-16 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

NMOG NMHC CO / 10 NOx FE / 100

Emissions or Fuel Economy (g/mile or mpg)

LA92 Test Cycle

1999 Toyota Corolla: Tier 1

Fig. C.29. Non-methane organic gas (NMOG), non-methane hydrocarbons (NMHC), carbon 

monoxide (CO), oxides of nitrogen (NOX), and fuel economy (FE) for 1999 Toyota Corolla on LA92 

cycle. Bars show average of 3 tests at 75°F. 

0.00

1.00

2.00

3.00

4.00

5.00

6.00

E0 E10 E15 E20 E0 E10 E15 E20 E0 E10 E15 E20

Ethanol ( /10) Acetaldehyde Formaldehyde

Ethanol or Aldehyde Emissions (mg/mile)

LA92 Test Cycle

1999 Toyota Corolla: Tier 1

Fig. C.30. Ethanol, acetaldehyde, and formaldehyde emissions for 1999 Toyota 

Corolla on LA92 cycle. Bars show average of 3 tests at 75°F. 
C-17 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

E0

E10E15E20

NMOG NMHC CO / 10 NOx FE / 100

Emissions or Fuel Economy (g/mile or mpg)

LA92 Test Cycle

2004 VW Golf GTI: Tier 2, Bin 8

Fig. C.31. Non-methane organic gas (NMOG), non-methane hydrocarbons (NMHC), 

carbon monoxide (CO), oxides of nitrogen (NOX), and fuel economy (FE) for 2004 

Volkswagen Golf GTI on LA92 cycle. Bars show average of 3 tests at 75°F. 

0.00

0.25

0.50

0.75

1.00

1.25

1.50

1.75

E0 E10 E15 E20 E0 E10 E15 E20 E0 E10 E15 E20

Ethanol ( /10) Acetaldehyde Formaldehyde

Ethanol or Aldehyde Emissions (mg/mile)

LA92 Test Cycle

2004 VW Golf GTI: Tier 2, Bin 8

Fig. C.32. Ethanol, acetaldehyde, and formaldehyde emissions for 2004 Volkswagen 

Golf GTI on LA92 cycle. Bars show average of 3 tests at 75°F. 
D-1 

APPENDIX D 

SMALL ENGINE FULL-USEFUL-LIFE TESTING 

D.1 EMISSIONS 

The following figures and tables show the full set of exhaust emissions data for the 

full-useful-life (full-life) small, non-road engine (SNRE) testing at the Transportation Research 

Center (TRC). Figures show the brake-specific emissions for the composite of the appropriate 6-mode 

(Class I engines) or 2-mode (Class IV engines) test. Data from the new condition are shown for all 

engines with E0 fuel and then each engine on its respective ethanol blend (E10, E15, or E20). When 

available, full-life data are also shown on the same figure. Trendlines are simple linear regressions for 

the new or full-life condition, as noted in the figures. The dedicated E0 engine results are shown for 

reference but were not used in the trendline regression since these engines ran only the E0 fuel. 

Figures are arranged first by engine type, then by emissions constituent. The HC emissions results 

shown here are as indicated by the flame ionization detector (FID) and do not include any correction 

for oxygenated compounds in the exhaust such as ethanol or aldehydes. 

Figures D.1 through D.4 show the hydrocarbon (HC), oxides of nitrogen (NOX), HC + NOX, and 

CO emissions for the Class I Briggs and Stratton power washer engines on the TRC protocol. The 

Briggs and Stratton engines were emissions tested on the dynamometer using two different 6-mode 

protocols. On the TRC protocol, mode 1 for the Briggs and Stratton engine was under governor 

control to match the spray condition used during aging. Similar plots are shown in Figs. D5 through 

D.8 for the same engines on the BASCO protocol. On the BASCO protocol, the throttle was 

mechanically fixed to the wide-open position, overriding the governor for mode 1. This protocol was 

only run on PW1–PW4 at the full-life condition; thus, PW5 with E0 fuel was also tested on the 

BASCO protocol for a new engine baseline comparison. 

0

5

10

15

20

25

30

35

40

45

E0 E10 E15 E20

HC Emissions (g/kWh)

0

5

10

15

20

25

30

35

40

45

B&S PW1 (new) PW2 (new) PW3 (new) PW4 (new)

PW1 (full life) PW2 (full life) PW3 (full life) PW4 (full life)

new engine

trendline

Full-life

trendline

Fig. D.1. Hydrocarbon (HC) emissions for Class I Briggs and Stratton 

power washer engines on Transportation Research Center protocol at new and 

full-useful-life (full-life) condition. Solid colors represent tests in the new condition 

while striped bars of the same color represent the same engine at the full-life 

condition. 
D-2 

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

E0 E10 E15 E20

NOx Emissions (g/kWh)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

B&S PW1 (new) PW2 (new) PW3 (new) PW4 (new)

PW1 (full life) PW2 (full life) PW3 (full life) PW4 (full life)

new engine

trendline

Full-life

trendline

Fig. D.2. Nitrogen oxide (NOX) emissions for Class I Briggs and Stratton power 

washer engines on the Transportation Research Center protocol at new and fulluseful-life (full-life) condition. Solid colors represent tests in the new condition while 

striped bars of the same color represent the same engine at the full-life condition. 

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

45.0

50.0

E0 E10 E15 E20

HC+NOx Emissions (g/kWh)

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

45.0

50.0

B&S PW1 (new) PW2 (new) PW3 (new) PW4 (new)

PW1 (full life) PW2 (full life) PW3 (full life) PW4 (full life)

new engine

trendline

Full-life

trendline

Fig. D.3. Hydrocarbon (HC) + nitrogen oxide (NOX) emissions for Class I 

Briggs and Stratton power washer engines on the Transportation Research Center 

protocol at new and full-useful-life (full-life) condition. Solid colors represent tests in 

the new condition while striped bars of the same color represent the same engine at the 

full-life condition.
D-3 

0

100

200

300

400

500

600

700

800

E0 E10 E15 E20

CO Emissions (g/kWh)

0

100

200

300

400

500

600

700

800

B&S PW1 (new) PW2 (new) PW3 (new) PW4 (new)

PW1 (full life) PW2 (full life) PW3 (full life) PW4 (full life)

new engine

trendline

Full-life

trendline

Fig. D.4. Carbon monoxide emissions for Class I Briggs and Stratton power 

washer engines on the Transportation Research Center protocol at new and fulluseful-life (full-life) condition. Solid colors represent tests in the new condition while 

striped bars of the same color represent the same engine at the full-life condition. 

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

18.0

20.0

E0 E10 E15 E20

HC Emissions (g/kWh)

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

18.0

20.0

PW5 (new) PW1 (full life) PW2 (full life) PW3 (full life) PW4 (full life)

Full-life

trendline

Fig. D.5. Hydrocarbon (HC) emissions for Class I Briggs and Stratton power 

washer engines on the Briggs and Stratton Company (BASCO) protocol. Only PW5 

was baselined on E0 in new condition on the BASCO protocol. The solid black bar is 

for the new PW5 data, while the striped bars represent the full-useful-life (full-life) 

condition as in previous figures. 
D-4 

0.0

1.0

2.0

3.0

4.0

5.0

6.0

E0 E10 E15 E20

NOx Emissions (g/kWh)

0.0

1.0

2.0

3.0

4.0

5.0

6.0

PW5 (new) PW1 (full life) PW2 (full life) PW3 (full life) PW4 (full life)

Full-life

trendline

Fig. D.6. Nitrogen oxide (NOX) emissions for Class I Briggs and Stratton 

power washer engines on the Briggs and Stratton Company (BASCO) protocol at 

new and full-useful-life (full-life) condition. Only PW5 was baselined on E0 in new 

condition on the BASCO protocol. The solid black bar is for the new PW5 data, while 

the striped bars represent the full-life condition as in previous figures. 

0.0

5.0

10.0

15.0

20.0

25.0

E0 E10 E15 E20

HC+NOx Emissions (g/kWh)

0.0

5.0

10.0

15.0

20.0

25.0

PW5 (new) PW1 (full life) PW2 (full life) PW3 (full life) PW4 (full life)

Full-life

trendline

Fig. D.7. Hydrocarbon (HC) + nitrogen oxide (NOX) emissions for Class I Briggs 

and Stratton power washer engines on the Briggs and Stratton Company (BASCO) 

protocol at new and full-useful-life (full-life) condition. Only PW5 was baselined on E0 in 

new condition on the BASCO protocol. The solid black bar is for the new PW5 data, while 

the striped bars represent the full-life condition as in previous figures. 
D-5 

0

50

100

150

200

250

300

350

400

450

500

E0 E10 E15 E20

CO Emissions (g/kWh)

0

50

100

150

200

250

300

350

400

450

500

PW5 (new) PW1 (full life) PW2 (full life) PW3 (full life) PW4 (full life)

Full-life

trendline

Fig. D.8. Carbon monoxide emissions for Class I Briggs and Stratton power 

washer engines on the Briggs and Stratton Company (BASCO) protocol at new 

and full-useful-life (full-life) condition. Only PW5 was baselined on E0 in new 

condition on the BASCO protocol. The solid black bar is for the new PW5 data, while 

the striped bars represent the full-life condition as in previous figures. 

The same emissions constituents, in the same order, are shown for the Honda generators in 

Figs. D.9 through D.12. The Honda generators were tested using a 6-mode protocol, although the 

generator was used as the engine brake, using an electrical load bank to vary the load from mode 1 to 

mode 6. 

0

2

4

6

8

10

12

14

16

E0 E10 E15 E20

HC Emissions (g/kWh)

0

2

4

6

8

10

12

14

16

Honda G1 (new) G2 (new) G3 (new) G4 (new)

G1 (full life) G2 (full life) G3 (full life) G4 (full life)

new engine

trendline

Full-life

trendline

Fig. D.9. Hydrocarbon (HC) emissions for Class I Honda generator engines at 

new and full-useful-life (full-life) condition. Solid colors represent tests in the new 

condition while striped bars of the same color represent the same engine at the full-life 

condition. 
D-6 

0

2

4

6

8

10

12

E0 E10 E15 E20

NOx Emissions (g/kWh)

0

2

4

6

8

10

12

Honda G1 (new) G2 (new) G3 (new) G4 (new)

G1 (full life) G2 (full life) G3 (full life) G4 (full life)

new engine

trendline Full-life

trendline

Fig. D.10. Nitrogen oxide (NOX) emissions for Class I Honda generator engines at 

new and full-useful-life (full-life) condition. Solid colors represent tests in the new 

condition while striped bars of the same color represent the same engine at the full-life 

condition. 

0

5

10

15

20

25

E0 E10 E15 E20

HC+NOx Emissions (g/kWh)

0

5

10

15

20

25

Honda G1 (new) G2 (new) G3 (new) G4 (new)

G1 (full life) G2 (full life) G3 (full life) G4 (full life)

new engine

trendline

Full-life

trendline

Fig. D.11. Hydrocarbon (HC) + nitrogen oxide (NOX) emissions for Class I 

Honda generator engines at new and full-useful-life (full-life) condition. Solid colors 

represent tests in the new condition while striped bars of the same color represent the 

same engine at the full-life condition. 
D-7 

0

50

100

150

200

250

300

350

400

E0 E10 E15 E20

CO Emissions (g/kWh)

0

50

100

150

200

250

300

350

400

Honda G1 (new) G2 (new) G3 (new) G4 (new)

G1 (full life) G2 (full life) G3 (full life) G4 (full life)

new engine

trendline

Full-life

trendline

Fig. D.12. Carbon monoxide emissions for Class I Honda generator engines at 

new and full-useful-life (full-life) condition. Solid colors represent tests in the new 

condition while striped bars of the same color represent the same engine at the full-life 

condition. 

Figures D.13 through D.16 show the HC, NOX, HC + NOX, and CO emissions for the residential 

Class IV Weed Eater blowers. The blowers were tested on the 2-mode test cycle using the blower 

wheel as the engine brake. The same emissions constituents, in the same order, are shown for the 

commercial Class IV Stihl line trimmers in Figs. D.17 through D.20. The Stihl engines were tested on 

the 2-mode test cycle per CFR guidelines on the dynamometer. 

0

10

20

30

40

50

60

E0 E10 E15 E20

HC Emissions (g/kWh)

0

10

20

30

40

50

60

Weedeater B2 (new) B5 (new) B7 (new) B3 (new)

B6 (new) B5 (full life) B6 (full life)

new engine

trendline

Full-life

trendline

Fig. D.13. Hydrocarbon (HC) emissions for Class IV Weed Eater blower 

engines at new and full-useful-life (full-life) condition. Solid colors represent tests in 

the new condition while striped bars of the same color represent the same engine at the 

full-life condition. 
D-8 

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

E0 E10 E15 E20

NOx Emissions (g/kWh)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

Weedeater B2 (new) B5 (new) B7 (new) B3 (new)

B6 (new) B5 (full life) B6 (full life)

new engine

trendline

Full-life

trendline

Fig. D.14. Nitrogen oxide (NOX) emissions for Class IV Weed Eater blower 

engines at new and full-useful-life (full-life) condition. Solid colors represent tests in 

the new condition while striped bars of the same color represent the same engine at the 

full-life condition. 

0

10

20

30

40

50

60

70

E0 E10 E15 E20

HC+NOx Emissions (g/kWh)

0

10

20

30

40

50

60

70

Weedeater B2 (new) B5 (new) B7 (new) B3 (new)

B6 (new) B5 (full life) B6 (full life)

new engine

trendline

Full-life

trendline

Fig. D.15. Hydrocarbon (HC) + nitrogen oxide (NOX) emissions for Class IV 

Weed Eater blower engines at new and full-useful-life (full-life) condition. Solid colors 

represent tests in the new condition while striped bars of the same color represent the same 

engine at the full-life condition. 
D-9 

0

50

100

150

200

250

300

350

400

450

500

E0 E10 E15 E20

CO Emissions (g/kWh)

0

50

100

150

200

250

300

350

400

450

500

Weedeater B2 (new) B5 (new) B7 (new) B3 (new)

B6 (new) B5 (full life) B6 (full life)

new engine

trendline

Full-life

trendline

Fig. D.16. Carbon monoxide emissions for Class IV Weed Eater blower 

engines at new and full-useful-life (full-life) condition. Solid colors represent tests in 

the new condition while striped bars of the same color represent the same engine at the 

full-life condition. 

0

10

20

30

40

50

60

70

80

90

E0 E10 E15 E20

HC Emissions (g/kWh)

0

10

20

30

40

50

60

70

80

90

Stihl T1 (new) T2 (new) T3 (new) T4 (new)

T1 (full life) T2 (full life) T3 (full life) T4 (full life)

new engine

trendline

Full-life

trendline

Fig. D.17. Hydrocarbon (HC) emissions for Class IV Stihl line trimmer 

engines at new and full-useful-life (full-life) condition. Solid colors represent 

tests in the new condition while striped bars of the same color represent the same 

engine at the full-life condition. 
D-10 

0

1

2

3

4

5

6

7

8

9

E0 E10 E15 E20

NOx Emissions (g/kWh)

0

1

2

3

4

5

6

7

8

9

Stihl T1 (new) T2 (new) T3 (new) T4 (new)

T1 (full life) T2 (full life) T3 (full life) T4 (full life)

new engine

trendline

Full-life

trendline

Fig. D.18. Nitrogen oxide (NOX) emissions for Class IV Stihl line trimmer engines 

at new and full-useful-life (full-life) condition. Solid colors represent tests in the new 

condition while striped bars of the same color represent the same engine at the full-life 

condition. 

0

10

20

30

40

50

60

70

80

90

E0 E10 E15 E20

HC+NOx Emissions (g/kWh)

0

10

20

30

40

50

60

70

80

90

Stihl T1 (new) T2 (new) T3 (new) T4 (new)

T1 (full life) T2 (full life) T3 (full life) T4 (full life)

new engine

trendline

Full-life

trendline

Fig. D.19. Hydrocarbon (HC) + nitrogen oxide (NOX) emissions for Class IV 

Stihl line trimmer engines at new and full-useful-life (full-life)condition. Solid 

colors represent tests in the new condition while striped bars of the same color represent 

the same engine at the full-life condition. 
D-11 

0

100

200

300

400

500

600

700

800

E0 E10 E15 E20

CO Emissions (g/kWh)

0

100

200

300

400

500

600

700

800

Stihl T1 (new) T2 (new) T3 (new) T4 (new)

T1 (full life) T2 (full life) T3 (full life) T4 (full life)

new engine

trendline

Full-life

trendline

Fig. D.20. Carbon monoxide emissions for Class IV Stihl line trimmer 

engines at new and full-useful-life (full-life) condition. Solid colors represent tests in 

the new condition while striped bars of the same color represent the same engine at the 

full-life condition. 

The tables that follow show the composite emissions results for all new engine and full-life tests 

at TRC, including the average of a series of tests, the maximum and minimum results for those tests, 

and the coefficients of variation (COVs). The COV for a full-life test on a given engine is generally 

lower than that for the same engine in the new condition on the same fuel. As stated previously, the 

engines in this program were run for 2 hr for initial break-in before emissions testing. Although none 

of the owner’s manuals specified any required break-in period, an EPA publication*

 suggests that 5 to 

10 hr of break-in are generally needed to stabilize emissions measurements. It is not clear whether 

longer break-in times would have harmonized the new condition and full-life COVs or impacted other 

noted trends. 

Tables D.1 through D.3 show the Briggs and Stratton power washer results. The Honda generator 

results are in Table D.4. The Weed Eater blower emissions are provided in Table D.5. Emissions 

results for the Stihl line trimmers are shown in Table D.6. 

 *

“EPA Technical Study on the Safety of Emission Controls for Nonroad Spark-Ignition Engines < 50 Horsepower,” 

EPA420-R-06-006, March 2006. 
D-12 

Table D.1. Briggs and Stratton power washer baseline E0 emissions on the TRC protocol, 

at new (after initial break-in) condition and at full-useful-life (full-life) condition 

Briggs and Stratton (Residential, Class I) power washer emissions 

(g/kW-hr) 

E0 baseline data, TRC protocol 

New condition Full-life condition 

HC NOX HC + NOX CO HC NOX HC + NOX CO 

Power washer 1 

Avg 11.1 2.1 13.2 312 11.1 3.7 14.8 164 

Max 13.1 2.3 15.3 350 11.8 4.3 15.2 205 

Min 9.5 1.9 11.8 241 10.1 3.1 14.3 142 

COV 14% 9% 11% 16% 8% 15% 3% 22% 

Power washer 2 

Avg 12.6 2.0 14.6 330 18.2 1.9 20.1 450 

Max 13.0 2.2 14.9 351 19.0 2.0 20.9 463 

Min 12.1 1.9 14.1 311 17.5 1.9 19.5 438 

COV 3% 7% 3% 5% 4% 2% 3% 3% 

Power washer 3 

Avg 16.6 1.6 18.1 347 41.4 1.6 43.1 724 

Max 17.2 1.8 18.7 409 42.4 1.7 44.0 760 

Min 15.8 1.4 17.4 294 39.7 1.6 41.3 695 

COV 4% 9% 4% 14% 4% 2% 3% 5% 

Power washer 4 

Avg 16.5 1.4 17.9 402 32.8 1.6 34.4 472 

Max 17.8 1.4 19.2 426 34.3 1.7 35.9 492 

Min 15.2 1.4 16.6 379 30.3 1.6 32.0 455 

COV 11% 0% 10% 8% 7% 3% 6% 4% 
D-13 

Table D.2. Briggs and Stratton power washer emissions on the TRC protocol 

in new and full-useful-life (full-life) condition with respective ethanol blends 

Briggs and Stratton (Residential, Class I) power washer emissions 

(g/kW-hr) 

Ethanol blend data, TRC protocol 

New condition Full-life condition 

HC NOX HC + NOX CO HC NOX HC + NOX CO 

Power washer 1 (E0 fuel) 

Avg 11.1 2.1 13.2 312 11.1 3.7 14.8 164 

Max 13.1 2.3 15.3 350 11.8 4.3 15.2 205 

Min 9.5 1.9 11.8 241 10.1 3.1 14.3 142 

COV 14% 9% 11% 16% 8% 15% 3% 22% 

Power washer 2 (E10 fuel) 

Avg 13.8 2.5 16.3 279 14.4 2.0 16.4 329 

Max 14.4 2.6 17.0 295 15.8 2.1 17.8 368 

Min 13.1 2.2 15.3 253 13.4 2.0 15.5 304 

COV 4% 7% 4% 6% 9% 2% 8% 11% 

Power washer 3 (E15 fuel) 

Avg 11.9 1.9 13.9 186 32.8 1.7 34.5 458 

Max 13.0 2.0 14.9 198 34.6 1.8 36.3 505 

Min 10.5 1.9 12.4 163 31.7 1.6 33.4 404 

COV 9% 2% 8% 9% 5% 4% 4% 11% 

Power washer 4 (E20 fuel) 

Avg 17.0 1.9 18.9 162 24.6 2.0 26.6 202 

Max 23.6 2.0 25.4 222 25.6 2.0 27.6 209 

Min 13.6 1.8 15.5 112 23.3 1.9 25.3 194 

COV 27% 4% 24% 28% 5% 2% 4% 4% 
D-14 

Table D.3. Briggs and Stratton power washer emissions on the BASCO protocol, 

E0 and ethanol blends. 

(PW1–PW4 at full-useful-life (full-life) condition, PW5 in new condition.)

Briggs and Stratton (Residential, Class I) power washer emissions 

(g/kW-hr) 

BASCO protocol 

E0 fuel Ethanol blend 

HC NOX HC + NOX CO HC NOX HC + NOX CO 

Power washer 1 (E0 fuel) 

Avg 16.1 5.3 21.3 227 

Max 17.8 5.4 22.9 233 

Min 13.7 5.1 19.2 216 

COV 12% 3% 8% 4% 

(E0 fuel) power washer 2 (E10 fuel) 

Avg 11.5 2.2 13.7 429 16.9 2.5 19.4 384 

Max 12.6 2.3 14.8 433 20.7 2.7 23.2 414 

Min 10.0 2.1 12.0 423 10.4 2.2 13.1 344 

COV 10% 5% 9% 1% 30% 9% 25% 8% 

(E0 fuel)power washer 3 (E15 fuel) 

Avg 18.6 2.1 20.8 396 16.9 2.6 19.5 291 

Max 20.6 2.3 22.7 439 19.3 2.9 21.7 337 

Min 17.1 2.1 19.4 321 14.1 2.4 16.7 261 

COV 8% 4% 7% 14% 14% 9% 12% 12% 

(E0 fuel) power washer 4 (E20 fuel) 

Avg 16.2 2.7 18.9 332 15.5 4.6 20.1 155 

Max 17.5 2.9 20.0 341 17.1 4.8 21.3 173 

Min 15.1 2.5 17.9 315 13.9 4.3 18.7 143 

COV 7% 6% 5% 4% 9% 5% 6% 9% 

Power washer 5 (E0 fuel, new condition)

Avg 11.9 4.5 16.4 241 

Max 12.8 5.0 17.8 266 

Min 11.1 3.9 15.6 228 

COV 6% 11% 6% 8% 
D-15 

Table D.4. Honda generator emissions at new and full-useful-life (full-life) condition, 

E0 baseline and respective ethanol blends 

Honda (Commercial, Class I) generator emissions 

(g/kW-hr) 

New condition Full-life condition 

HC NOX HC + NOX CO HC NOX HC + NOX CO 

Generator 1 (E0 fuel) 

Avg 5.2 3.7 9.0 329 6.5 3.7 10.2 374 

Max 5.8 4.0 9.8 346 6.6 3.8 10.4 378 

Min 4.4 3.4 7.8 320 6.4 3.6 10.0 371 

COV 14% 9% 12% 4% 2% 3% 2% 1% 

Generator 2 (E0 fuel) 

Avg 5.1 3.6 8.8 306 5.3 4.0 9.2 320 

Max 5.2 3.7 8.9 317 5.5 4.0 9.4 321 

Min 5.0 3.5 8.7 299 5.2 3.9 9.1 317 

COV 2% 3% 1% 3% 3% 1% 1% 1% 

Generator 3 (E0 fuel) 

Avg 6.2 4.4 10.6 310 8.8 3.8 12.6 359 

Max 6.8 4.7 11.0 320 8.9 3.9 12.6 360 

Min 5.6 4.2 10.3 298 8.6 3.7 12.5 357 

COV 10% 6% 3% 4% 2% 3% 0% 1% 

Generator 4 (E0 fuel) 

Avg 5.5 5.0 10.5 270 9.3 4.2 13.5 335 

Max 5.7 5.1 10.7 274 9.4 4.2 13.6 336 

Min 5.2 4.9 10.2 268 9.2 4.2 13.4 334 

COV 5% 2% 2% 1% 1% 0% 1% 0% 

Ethanol blends data 

Generator 2 (E10 fuel)

Avg 4.2 5.2 9.4 221 4.4 5.5 10.0 221 

Max 4.6 5.2 9.8 223 4.4 5.9 10.3 226 

Min 4.0 5.1 9.2 220 4.4 5.3 9.7 215 

COV 8% 1% 4% 1% 0% 5% 3% 3% 

Generator 3 (E15 fuel)

Avg 4.4 6.3 10.7 206 6.5 6.4 12.9 226 

Max 4.5 6.4 10.8 216 6.8 6.5 13.0 248 

Min 4.2 6.3 10.6 199 6.2 6.2 12.7 213 

COV 3% 2% 1% 4% 4% 2% 1% 8% 

Generator 4 (E20 fuel)

Avg 13.7 9.6 23.3 164 6.0 8.5 14.5 134 

Max 14.2 9.8 23.7 168 6.1 8.6 14.7 136 

Min 13.2 9.5 23.0 160 6.0 8.3 14.3 132 

COV 4% 1% 2% 2% 1% 2% 1% 1% 
D-16 

Table D.5. Weed Eater Featherlite blower emissions at new and full-useful-life (full-life) 

condition, E0 baseline and respective ethanol blends 

Weed Eater (Residential, Class IV) blower emissions 

(g/kWh) 

New condition Full-life condition 

HC NOX HC + NOX CO HC NOX HC + NOX CO 

Blower 2 (E0 fuel) 

Avg 47.6 0.3 47.9 366 Failed prior to full life 

Max 49.0 0.3 49.2 380

Min 46.7 0.3 47.0 352

CO 2% 11% 2% 3%

Blower 5 (E0 fuel) 

Avg 57.8 0.2 58.0 448 48.1 0.3 48.4 314

Max 60.1 0.2 60.4 475 50.9 0.4 51.3 333

Min 55.2 0.1 55.3 417 45.6 0.3 46.0 291

CO 4% 19% 4% 7% 6% 6% 6% 6%

Blower 7 (E0 fuel) 

Avg 38.4 0.2 38.6 239 Failed prior to full life 

Max 39.1 0.3 39.4 252

Min 37.3 0.2 37.5 228

CO 2% 12% 2% 4%

Blower 3 (E0 fuel) 

Avg 42.4 0.2 42.6 355 Failed prior to full life 

Max 43.2 0.2 43.4 370

Min 40.3 0.2 40.5 332

CO 3% 24% 3% 5%

Blower 6 (E0 fuel) 

Avg 49.8 0.3 50.0 353 43.3 1.1 44.4 83

Max 51.1 0.3 51.4 373 45.3 1.2 46.4 85

Min 48.1 0.3 48.4 312 41.8 1.0 43.0 81

CO 2% 7% 2% 8% 3% 9% 3% 2%

Ethanol blends 

Blower 5 (E10 fuel)

Avg 46.5 0.2 46.7 304 36.1 0.4 36.5 168

Max 52.9 0.2 53.1 383 37.4 0.5 37.8 184

Min 38.9 0.2 39.1 207 34.7 0.4 35.2 152

CO 15% 8% 15% 30% 4% 9% 4% 10%

Blower 7 (E15 fuel)

Avg 31.0 1.2 32.2 12

Max 32.9 1.3 34.1 12

Min 29.2 1.1 30.3 12

CO 5% 4% 5% 2%

Failed prior to full life 

Blower 3 (E15 fuel)

Avg 33.2 0.3 33.5 205

Max 34.0 0.3 34.2 224

Min 31.1 0.3 31.4 159

CO 4% 9% 4% 15%

Failed prior to full life 

Blower 6 (E20 fuel)

Avg 33.7 0.9 34.6 86 35.4 1.0 36.4 84

Max 34.9 1.0 35.7 88 38.6 1.1 39.7 116

Min 32.7 0.8 33.5 82 33.9 0.6 34.5 70

CO 3% 11% 3% 3% 6% 26% 6% 26%
D-17 

Table D.6. Stihl line trimmer emissions, new and full-useful-life (full-life) condition, 

E0 baseline and respective ethanol blends 

Stihl (Commercial, Class IV) line trimmer emissions 

(g/kW-hr) 

New condition Full-life condition 

HC NOX HC + NOX CO HC NOX HC + NOX CO 

Trimmer 1 (E0 fuel) 

Avg 33.6 3.3 36.9 347 76. 3.7 80.1 591 

Max 34.9 3.7 38.0 367 77. 3.8 80.9 603 

Min 30.8 2.9 34.5 320 75. 3.3 79.7 579 

COV 6% 11% 4% 6% 1% 6% 1% 2% 

Trimmer 2 (E0 fuel) 

Avg 29.9 4.1 33.9 285 65. 4.8 70.4 461 

Max 30.9 4.6 34.5 312 67. 5.4 73.2 503 

Min 28.8 3.7 33.4 251 62. 3.9 67.6 436 

COV 3% 12% 2% 10 4% 15% 4% 6% 

Trimmer 3 (E0 fuel) 

Avg 28.5 3.2 31.7 408 71. 2.5 73.7 712 

Max 29.4 3.4 32.5 425 74. 2.9 77.1 772 

Min 27.9 3.0 31.1 396 66. 1.8 69.1 670 

COV 2% 5% 2% 3% 5% 21% 5% 7% 

Trimmer 4 (E0 fuel) 

Avg 26.3 2.6 28.9 335 68. 3.0 71.8 603 

Max 27.9 2.8 30.4 350 69. 3.2 72.4 630 

Min 23.8 2.4 26.6 315 68. 2.6 71.1 586 

COV 7% 7% 6% 5% 1% 10% 1% 3% 

Ethanol blends data 

Trimmer 2 (E10 fuel)

Avg 26.4 4.5 30.9 265 53. 6.7 60.1 368 

Max 29.3 5.1 32.3 343 54. 7.2 61.6 381 

Min 24.7 3.0 29.7 234 52. 6.1 58.1 341 

COV 8% 23% 3% 20 2% 7% 3% 5% 

Trimmer 3 (E15 fuel)

Avg 20.3 6.9 27.2 249 59. 7.0 66.1 431 

Max 22.0 7.3 28.8 254 60. 7.2 67.0 441 

Min 18.6 6.8 25.5 237 57. 6.8 64.6 424 

COV 7% 3% 5% 3% 2% 2% 2% 2% 

Trimmer 4 (E20 fuel)

Avg 16.6 4.5 21.1 174 46. 6.4 52.8 363 

Max 17.1 4.6 21.6 192 46. 6.7 53.2 375 

Min 15.7 4.2 20.1 162 45. 6.2 51.6 356 

COV 4% 4% 3% 7% 2% 3% 1% 2% 
D-18 

D.2 TEMPERATURE 

The following figures show the full set of exhaust temperature data for the full-life SNRE testing 

at TRC (for completeness here, some are repeated from Sect. 3 of the report). The hottest engine 

condition is shown, which was the fast-idle or mode-6 condition for the Class I Briggs and Stratton 

and Honda engines and the full-power or mode-1 condition for the handheld Class IV Stihl and Weed 

Eater engines. Figure D.21 shows the Briggs and Stratton results. Temperatures for the Honda 

generators are shown in Fig. D.22. Weed Eater blower temperatures are presented in Fig. D.23. 

Figure D.24 shows the temperature results for the Stihl line trimmers. 

400

450

500

550

600

650

700

E0 E10 E15 E20

Exhaust Port Temperature (C)

400

450

500

550

600

650

700

PW1 (new) PW2 (new) PW3 (new) PW4 (new)

PW1 (full life) PW2 (full life) PW3 (full life) PW4 (full life)

new engine

trendline

Full-life

trendline

Fig. D.21. Exhaust port temperature for Class I Briggs and Stratton power 

washers at mode 6 (fast idle) at new and full-useful-life (full-life) condition. Solid 

colors represent tests at the new condition while striped bars of the same color 

represent the full-life condition. 
D-19 

600

650

700

750

800

E0 E10 E15 E20

Exhaust Port Temperature (C)

600

650

700

750

800

Honda G1(new) G2 (new) G3 (new) G4 (new)

G1 (full life) G2 (full life) G3 (full life) G4 (full life)

new engine

trendline

Full-life

trendline

Fig. D.22. Exhaust port temperature for Class I Honda generators at 

mode 6 (fast idle) at new and full-useful-life (full-life) condition. Solid colors 

represent tests at the new condition while striped bars of the same color represent the 

same engine at the full-life condition. Erratic operation of G4 at light loads with E20 

in the new condition resulted in lower exhaust temperature. 

500

525

550

575

600

625

E0 E10 E15 E20

Exhaust Port Temperature (C)

500

525

550

575

600

625

B2 (new) B5 (new) B3 (new) B7 (new)

B6 (new) B5 (full life) B6 (full life)

new engine

trendline

Full-life

trendline

 

Fig. D.23. Exhaust port temperature for Class IV Weed Eater Featherlite 

blower engines at mode 1 (full power) at new and full-useful-life (full-life) 

condition. Solid colors represent tests at the new condition while striped bars of the 

same color represent the same engine at the full-life condition. Only B5 and B6 

survived to be tested at the full-life condition. Blower-fuel combinations were as 

follows: B2-E0, B5-E10, B3 and B7-E15, B6-E20. 
D-20 

550

600

650

700

750

800

E0 E10 E15 E20

Exhaust Port Temperature (C)

550

600

650

700

750

800

Stihl T1 (new) T2 (new) T3 (new) T4 (new)

T1 (full life) T2 (full life) T3 (full life) T4 (full life)

new engine

trendline

Full-life

trendline

Fig. D.24. Exhaust port temperature for Class IV Stihl line trimmers at 

mode 1 (full power) at new and full-useful-life (full-life) condition. Solid colors 

represent tests at the new condition while striped bars of the same color represent the 

same engine at the full-life condition.