COORDINATING RESEARCH COUNCIL, INC.

3650 MANSELL ROAD · SUITE 140 · ALPHARETTA, GA 30022

CRC Report No. E-77-2

ENHANCED EVAPORATIVE EMISSION 

VEHICLES

March 2010
The Coordinating Research Council, Inc. (CRC) is a non-profit 

corporation supported by the petroleum and automotive equipment 

industries. CRC operates through the committees made up of 

technical experts from industry and government who voluntarily 

participate. The four main areas of research within CRC are : air 

pollution (atmospheric and engineering studies); aviation fuels, 

lubricants, and equipment performance, heavy-duty vehicle fuels, 

lubricants, and equipment performance (e.g., diesel trucks); and 

light-duty vehicle fuels, lubricants, and equipment performance 

(e.g., passenger cars). CRC’s function is to provide the mechanism 

for joint research conducted by the two industries that will help in 

determining the optimum combination of petroleum products and 

automotive equipment. CRC’s work is limited to research that is 

mutually beneficial to the two industries involved, and all 

information is available to the public.

CRC makes no warranty expressed or implied on the application of 

information contained in this report. In formulating and approving 

reports, the appropriate committee of the Coordinating Research 

Council, Inc. has not investigated or considered patents which may 

apply to the subject matter. Prospective users of the report are 

responsible for protecting themselves against liability for 

infringement of patents.
ii

Final Report 

ENHANCED EVAPORATIVE EMISSION VEHICLES

(CRC E-77-2)

Submitted to 

Coordinating Research Council, Inc.

3650 Mansell Road, Suite 140

Alpharetta, GA 30022

By

Harold M. Haskew, P.E.

Thomas F. Liberty

Harold Haskew & Associates, Inc.

425 W. Huron, Suite 230

Milford, MI 48381
iii

Acronyms

ATL................Automotive Testing Laboratories, Inc.

CFR ............Code of Federal Regulations

CRC............Coordinating Research Council, Inc.

FID.................Flame Ionization Detector

FTTP ..............Fuel Tank Temperature Profile

HC .................Hydrocarbon

HH&A............Harold Haskew & Associates

ID...............Internal Diameter

LA-92.............Unified Driving Cycle

MTBE ............Methyl Tertiary Butyl Ether

NBR ...............Nitrile Rubber or Acrylonitrile Butadiene Rubber

ORVR ............On-Board Refueling Vapor Recovery

PFI..................Port Fuel Injection

psi ..............Pounds per square inch

RL SHED.......Running Loss Sealed Housing for Evaporative Determination

RVP................Reid Vapor Pressure

SHED .............Sealed Housing for Evaporative Determination

TEFVO...........Temporary Emissions Following Vehicle Operation

THC................Total Hydrocarbon

VT SHED.......Variable Temperature Sealed Housing for Evaporative Determination
iv

Table of Contents

Page

Introduction

Background................................................................. 1

Contract History............................................................ 2

Period of Performance..................................................... 2

Test Program Overview

Vehicle Selection........................................................... 3

Vehicle Fleet................................................................ 3

Test Fuels....................................................................4

Adaption Period for Test Fuel Changes..................................4

The Test Concept........................................................... 5

Test Procedures............................................................10

Discussion of Test Results

Results

Static Permeation Rate....................................................17

Dynamic Permeation Rate................................................... 20

Hot Soak (“True”) Permeation Rate.................................... 22

Diurnal Permeation Rate................................................. 24

Tank Venting (Canister Breakthrough)................................ 25

Overall Trend Summary................................................... 27

Special Case: Vehicle 202 – 1996 Ford Taurus...................... 28

The “Implanted Leaks” Test Results................................... 32

Summary of Findings and Results...................................... 36

Appendix

Acknowledgements........................................................37

Steering Committee........................................................37

Fuel Inspections.............................................................38

Program Test Results.......................................................40

Individual Vehicle Diurnal Performance on the Various Fuels.......41

Ethanol Portion of Diurnal Emissions.................................. 45
v

List of Figures

Figure Description Page

1 Testing Activity................................................................. 2

2 Sealed Housing for Evaporative Determination (SHED)..................5

3 Control System Schematic.................................................... 6

4 Trap Canister................................................................... 6

5 Static Test – Tank Pressurization............................................ 7

6 Static Test – Fuel Pump Energized.......................................... 8

7 Testing Flow Chart............................................................ 9

8 Leak Test........................................................................ 12

9 Static Permeation Determination............................................ 13

10 Running Loss SHED......................................................... 14

11 Running Loss Driving Cycle................................................. 15

12 Running Loss Test Results................................................... 16

13 Static Permeation Rate Comparison......................................... 18

14 Running Loss Permeation Comparison......................................20

15 True Hot Soak Permeation Comparison.................................... 22

16 Day 1 Diurnal Permeation Comparison.....................................24

17 Diurnal Canister Breakthrough...............................................25

18 Trend Analysis Summaries....................................................27

19 Vehicle 202 Fuel Fill Pipe Leak............................................. 28

20 Implanted Leak Impact....................................................... 33

21 Vehicles 207 and 211 with Induced Leak – Static........................ 34

22 Vehicles 207 and 211 with Induced Leak – Running Loss............... 34

23 Vehicles 207 and 211 with Induced Leak – True Hot Soak.............. 35

24 Vehicles 207 and 211 with Induced Leak – Diurnal...................... 35

25-31 Diurnal Performance – Various Fuels – All Vehicles...................41-44

32-38 Diurnal Ethanol Portion - All Fuels – All Vehicles......................46-49
vi

List of Tables

Table Description Page

1 E77-2 Vehicle Fleet ...................................................................................3

2 Test Fuel Target Values.............................................................................4

3 Static Permeation Results .........................................................................19

4 Running Loss Permeation Results............................................................21

5 True Hot Soak Permeation Results...........................................................23

6 Diurnal Permeation Results ......................................................................25

7 Carbon Canister Diurnal Breakthrough Results .......................................26

8 Vehicle 202 Static Permeation Results.....................................................29

9 Vehicle 202 Dynamic Permeation Results ...............................................30

10 Vehicle 202 Diurnal Permeation Results..................................................30

11 Implanted Leak Impact on Diurnal Permeation........................................32

12 Fuel Inspection Results.............................................................................38

13 Overall Program Test Results...................................................................40

14 3 Day Diurnal Results...............................................................................45
vii

Executive Summary

This report describes an on-going investigation into the evaporative emission performance of 

light-duty vehicles as they exist in the United States population. Evaporative emissions are, in 

this context, the fuel-related emissions that escape from the vehicle at rest and during vehicle 

operation (omitting those that come from the tailpipe). The CRC E-77-2 Evaporative Emission 

Test Program, the subject of this report, evolved from the CRC E-77 Pilot Study (available at 

www.crcao.org, listed under “Publications: Emissions”) and used test procedures and insight 

borrowed from other CRC test programs, including E-65, Fuel Permeation from Automotive 

Systems. Automotive Testing Laboratories, Inc. (ATL), located in Mesa, AZ, conducted the 

tests for all these programs, including those that are the subject of this report. ATL has the

unique experience and facilities to perform evaporative emission programs of this nature.

For the follow-up study E-77-2, the sponsor selected eight vehicles for evaluation on five

gasoline fuel blends, including three levels of ethanol (zero, 10, and 20 volume percent). In 

addition, two of the vehicles were given a limited evaluation with implanted small leaks in the 

evaporative system. The selected vehicles were prepared for test, preconditioned for a minimum 

of four weeks on the test fuel when the ethanol level was changed, and then subjected to the test 

sequence.

The test fleet included one pre-enhanced evaporative system vehicle (1996 model year), five 

“Enhanced Evaporative” system vehicles (model years 1999 to 2001), and two “Tier 2” (Near 

Zero) vehicles from model year 2004 or later. The pre-enhanced vehicle was certified to a single 

day’s diurnal control. The enhanced control vehicles were subjected to a much more severe 

certification performance test, including a three day diurnal, a high temperature hot soak, and a 

measured running loss test. The certification test requirements for Tier 2 vehicles were similar to 

those for the enhanced vehicles, but at a standard of about one-fourth of the level for the 

enhanced vehicles. With the exception of the 1996 pre-enhanced vehicle, all were certified to 

the On-Board Refueling Vapor Recovery (ORVR) emission requirements. CRC owned all the 

vehicles, having previously purchased them for CRC Project E-74b (CO vs. RVP). 

Static permeation rate increased with an increase in ethanol level. Three of the five enhanced 

emission vehicles did not show an increase in permeation rate when tested with the 9 psi E0 

compared to the 7 psi E0.

The dynamic permeation rate (measured during vehicle operation) was higher with the E10 fuel 

compared to E0 for the enhanced vehicles. The E20 permeation rate was higher than E0 and the 

E10 fuel. The small sample size and limited data precludes us from making statements about 

statistical confidence, but this may indicate a trend. The near zero vehicle average increased as 

the ethanol level increased. Trends with volatility were mixed, or inconclusive.

There was a large increase in the hot soak value with the E10 fuel compared to the E0. The hot 

soak value with the E20 fuel was comparable to the E0 results, but lower than the E10.
viii

The Near Zero vehicles (2) had zero hot soak emissions when tested on the 10 psi E10 fuel 

(Figure 16). With only two vehicles and the very low levels attained, no statistically significant 

conclusions can be drawn from the data available.

The average Day 1 diurnal permeation for the five Enhanced Vehicles tended to increase as 

ethanol content increased (with the exception of the E20 fuel). Again, statistical conclusions are 

not appropriate given the small sample size and limited data.

This study included an evaluation of two vehicles with implanted vapor system leaks. This 

interest followed the information gathered in the Pilot Study where tests were run with a 

specially modified fuel cap containing a 0.02” diameter hole. The newer vehicles evaluated in 

this phase of the study were configured and certified to the Onboard Refueling Vapor 

Regulations (ORVR). These are capable of containing 95% or more control of the refueling 

vapors at up to 10 gallons per minute fueling rate. Where the Chevrolet Cavalier had a small 

(0.055” diameter) orifice and a long vapor tube venting the tank’s vapor space to the carbon 

canister (and then to the atmosphere), the ORVR compliant vehicles have a large (0.625”internal 

diameter), short vent hose to a low flow restriction carbon canister. The emission results 

measured with the ORVR vehicles were significantly lower than measured in previous studies 

with the pre-enhanced evaporative emission control systems. 

Summary of Findings and Results

The E-77-2 test program was a continuation of the previously published E-77 test project, and 

added eight vehicles tested on five fuels to the knowledge base. The permeation trends 

previously shown were present for the most part. The small sample size and limited number of 

tests preclude making statements about trends in emissions with statistical confidence, but in 

general:

o The newer vehicle groups had lower emission levels.

o Adding ethanol to the fuel increased permeation over the non-oxygenated levels.

o Increased volatility increased permeation levels on average, but produced mixed 

results on the individual vehicles. The effect of volatility needs additional study.

o SHED emission rates must be corrected for the ethanol error in the Flame 

Ionization Detector (FID), and the non-fuel methanol and refrigerant in the 

measurement.
1

ENHANCED EVAPORATIVE EMISSION VEHICLES

CRC E-77-2

INTRODUCTION

Background - The Coordinating Research Council (CRC)1has sponsored studies on evaporative 

emissions of vehicles for over two decades. Whereas the exhaust (or tailpipe) emissions have 

been extensively studied as a source of air pollution, and through the development of advanced 

control systems, reduced to very low levels in properly maintained and functioning vehicles, the 

non-tailpipe emissions levels are not as well understood or documented. 

This report describes an on-going investigation into the evaporative emission performance of 

light-duty vehicles as they exist in the American population. Evaporative emissions are, in this 

context, the fuel-related emissions that escape from the vehicle at rest, and during vehicle 

operation (omitting those that come from the tailpipe). The CRC E-77-2 Evaporative Emission 

Test Program, the subject of this report, evolved from the CRC E-77 Pilot Study and used test 

procedures and insight borrowed from other CRC test programs, including E-65, Fuel 

Permeation from Automotive Systems. All of these programs, including the subject of this 

report, were conducted at the Automotive Testing Laboratories, Inc. (ATL) in Mesa, AZ2, which 

provides unique experience and facilities to perform evaporative emission programs of this 

nature.

For the follow-up study E-77-2, the sponsor selected eight vehicles for evaluation on five

gasoline fuel blends, including three levels of ethanol (zero, 10, and 20 volume percent). In 

addition, two of the vehicles were given a limited evaluation with implanted small leaks in the 

evaporative system. The selected vehicles were prepared for test, preconditioned for a minimum 

of four weeks on the test fuel when the ethanol level was changed, and then subjected to the test 

sequence. The evaporative emission test sequence consisted of the following four parts:

1. Static Permeation Rate Measurement at 86°F (Includes leak checks)

2. Dynamic (Running Loss) Permeation and Canister Loss Measurement at 86°F

3. Hot Soak (“True” or Net Value) following the Dynamic Test at 86°F 

4. Two Day Diurnal (65°F to 105°F) Permeation and Canister Loss Measurement

While one objective of this project was to measure the evaporative emission performance of the 

selected vehicles, a second objective was to develop and refine the test procedures and analysis 

methods. We have included documentation of these test procedures beginning on page 10.

Each vehicle started the evaluation with a 4-week preconditioning on 10 psi E10 fuel, and then 

ran the 10 psi E10 evaporative emission test sequence (static, running loss, hot soak, and 

 

1

 Coordinating Research Council, Inc., 3650 Mansell Road, Suite 140, Alpharetta, GA 30022, (678) 795-0506, 

www.crcao.org

2

 ATL, 263 S. Mulberry Street, Mesa, AZ, (480) 649 7906, www.ATL-AZ.com, Greg Barton, President
2

diurnal). Based on the previous experience with CRC E-65, it was thought that the four week 

period was appropriate for the permeation rate to re-stabilize following the fuel change. After 

validation and committee approval of the data, the fuel was changed to a lower volatility (7 psi) 

E10 fuel, allowed to re-stabilize for up to one week, and then re-evaluated on the emission test 

sequence. The shorter stabilization period was thought appropriate to allow the system to 

respond to a volatility change of a similar ethanol content fuel.

Once the test results were approved, the vehicle was refueled with 9 psi E0 fuel, and again 

subjected to a 4-week minimum re-stabilization. The evaporative performance test sequence was 

then repeated, and repeated again with a 7 psi E0 fuel after a one week stabilization period. The 

final test fuel was the 9 psi E20 mixture, again after a 4-week stabilization.

Contract History – Members of the CRC Real World Vehicle Emissions and Emissions 

Modeling Group, together with technical representatives from EPA and the California Air 

Resources Board, met at EPA’s Ann Arbor office on December 14, 2006, and outlined the scope 

and content of the study. A follow-on to the CRC E-77 Pilot Study, it included evaporative 

emission performance testing of eight recent model light duty vehicles using three ethanol levels 

(E0, E10, and E20) at various RVP levels. The vehicles were not the same as those used in the 

Pilot Study.

The original contract included eight vehicles tested on four fuels (7 psi E0, 9 psi E0, 7 psi E10, 

and 10 psi E10). A later contract modification added limited testing on two vehicles with 

implanted leaks, added testing on 9 psi E20 Fuel, and included monies to pay for retesting and 

repairs of a problem vehicle.

Period of Performance – Vehicle preconditioning was first reported in the Volume 3, Number 1 

progress report dated April 22, 2007, and continued through Volume 3, Number 83 dated 

November 16, 2008. Figure 1 depicts the actual program testing activity. The colored bars 

indicate both the preconditioning and the vehicle performance testing period. Analysis and 

comments were contained in the progress reports through November. 

I D Vehicle Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

202 1996 Ford Taurus

204 1999 Honda Accord

205 2001 Toyota Corolla

207 2005 Dodge Caravan

207L Caravan with Leak

211 2004 Toyota Camry

211L Camry with Leak

212 2006 Ford Taurus

214 2004 Ford Escape

215 2004 Toyota Highlander

2007 2008

E77-2 Project Timing

Figure 1 – Testing Activity
3

TEST PROGRAM OVERVIEW

Vehicle Selection

The sponsors chose to evaluate eight vehicles on five fuel blends. The vehicles were defined to 

be one pre-enhanced evaporative system vehicle (1996 model year), five “Enhanced 

Evaporative” system vehicles (model years 1999 to 2001), and two “Tier 2” (Near Zero) vehicles 

that were 2004 model year vehicles or later. The pre-enhanced vehicle was certified to a single 

day’s diurnal control. The enhanced control vehicles were subject to a much more severe 

performance test, including a three-day diurnal, a high temperature hot soak, and a measured 

running loss test. The Tier 2 vehicles’ test requirements were similar to the enhanced vehicles, 

but at a standard of about one-fourth of the enhanced vehicles level. All but the 1996 preenhanced vehicle were certified to the On-Board Refueling Vapor Recovery (ORVR) emission 

requirements. All the vehicles were the property of CRC, having been bought, along with other 

vehicles, for CRC Project E-74b (CO vs. RVP). The vehicles were originally purchased for the 

E-74b project from local retail sources in the Phoenix, AZ area.

Each candidate vehicle was checked at the start of the test program to make sure that there were 

no system leaks, to verify system purge was present, and to generally establish that it was safe to

operate.

Vehicle Fleet

Table 1 below lists and describes the eight vehicles studied in this program. A more complete 

file containing the vehicle road load coefficients and dynamometer settings is included in the “E77-2 Companion Files.xls” (Microsoft EXCELTM) file available on the CRC website, 

www.crcao.org.

Table 1

Vehicle

Number

Model

Year Make Model

Odometer

Miles Evap Standards Evap Family

Fuel 

Tank

Plastic/

Metal

202 1996 Ford Taurus 86,538 Pre-Enhanced TFM1115AYMEB Metal

204 1999 Honda Accord 100,418 Enhanced/ORVR XHNXR0130AAA Metal

205 2001 Toyota Corolla 92,047 Enhanced/ORVR 1TYXR0115AK1 Metal

207 2001 Dodge Caravan 92,740 Enhanced/ORVR 1CRXR0165XAA Plastic

214 2004 Ford Escape 40,188 Enhanced/ORVR 4FMXR0110BBE Plastic

215 2004 Toyota Highlander 88,000 Enhanced/ORVR 4TYXR0165PZ1 Plastic

211 2004 Toyota Camry 42,592 Near Zero/ORVR 4TYXR0130A11 Plastic

212 2006 Ford Taurus 28,354 Near Zero/ORVR 6FMXR0185GAK Metal

E77-2 Vehicle Fleet
4

Test Fuels

The fuel comparisons selected for this project were three levels of ethanol content with volatility

varied as listed in Table 2, below. 

 Table 2

 Test Fuel Target Values

7 psi 9 psi 10 psi

E0 X X

E10 X X

E20 X

CRC had fuels remaining from Project E-74 in quantities sufficient to conduct this program, e.g., 

7 psi E0 and E10, and 9 psi E203. Inspection records of the base fuels are repeated in the 

Appendix, using their E-74b identifications, fuels 6, 7 and 4, respectively. The nominal 7 psi 

fuels, both E0 and E10, were locally blended with commercial butane to make the higher 

volatility 9 psi E0, and the 10 psi E10. The blends were done in drum batches, approximately 50 

gallons at a time, by adding small amounts of butane, circulating for a brief period, then 

sampling and determining the new volatility with a “Grabner4” instrument, using test procedures 

described in ASTM D 5191. The higher (10 instead of 9) volatility of the E10 fuel was specified 

because many localities permit “splash blending” of ethanol to gasoline and allow a 1 psi 

volatility exemption for their vapor pressure limits.

Adaption Period for Test Fuel Change

Many areas of the United States were required5to use an oxygenated fuel to improve vehicle 

emissions, especially during the summer season. While MTBE was the most common 

oxygenate, ethanol was also used. CRC Project E-65 demonstrated that the permeation of 

vehicle fuel systems increased with the use of fuels containing ethanol, compared to fuels with 

MTBE, or no oxygenate. CRC Project E-65 also demonstrated that if ethanol had been 

previously used, and the fuel replaced with a non-ethanol blend, it could take two to four weeks 

for the ethanol increase to dissipate. 

The protocols adopted for this test program were to require a minimum of four weeks of vehicle 

exposure to a new fuel when first introducing 10 or 20 volume percent ethanol to the vehicle, and 

the same period of time when moving to an ethanol-free (E0) fuel. Note, when changing RVP 

only, a one week exposure has been demonstrated as sufficient.

 

3

 While the E20 target was 9 psi, the average inspection value (5 labs) was 8.5 psi. The sponsor chose to continue 

the test at this level. 

4

 www.grabner-instruments.com, MINIVAP VPS / VPSH Vapor Pressure Tester, The portable MINIVAP VPS 

and VPSH vapor pressure testers are the worldwide accepted standard instruments for determination of the vapor 

pressure of gasoline according to ASTM D 5191, ASTM D 6377, ASTM D 6378 and EN 13016 1+2.

5

 The requirement for oxygen content in RFG fuels was removed by EPA in May of 2005, as directed by the 

Energy Policy Act of 2005. The Renewable Fuels Standard, requiring renewable fuels (e.g., ethanol) in increasing 

amounts over the years, replaces the mandate.
5

The Test Concept: Measuring Leaks, Permeation and Diurnal Vapor Losses

Mass emissions are measured in a VT SHED or Variable Temperature Sealed Housing for 

Evaporative Determination. The SHED test method 

combines all three emission mechanisms (leaks, 

diurnal venting, and permeation) into a single test 

result.

The SHED technique involves placing the vehicle in 

a sealed enclosure (Figure 2), and calculating the 

mass in the enclosure from the volume, density, and 

concentration in the enclosure at the start and end of 

a time period. The difference between the mass at 

the start and end of test is the emission rate, e.g., 

grams per unit time. 

CRC’s E-77 emission test programs have 

developed (and strive to continually improve) 

new methodologies for understanding and quantifying vehicle evaporative emission rates. The 

concept partitions and assigns the vehicle’s contribution to the evaporative emission inventory 

into three mechanisms:

1. Permeation

2. Tank vapor venting

3. Leaks (with two subsets - Liquid and Vapor)

Permeation is the migration of HC through the various elastomers (polymers) in a vehicle fuel 

system6. Previous testing has shown that permeation rate is strongly affected by the material’s 

temperature, doubling for each 10oC (18oF) increase in the range of normal summer 

temperatures. It is also strongly affected by gasoline composition, especially with ethanolcontaining fuels.

 

6

 “Fuel Permeation from Automotive Systems: Final Report CRC Project E-65,” Haskew, Liberty and McClement, 

September 2004, available on the CRC and California Air Resources Board websites.

Figure 2 – Sealed Housing for Evaporative 

Determination
6

Tank vapor venting emissions are controlled by fitting a carbon canister to the atmospheric tank 

vent. Figure 3 is a schematic of a typical early control system. During a daily heating period, the 

temperature of the vehicle’s fuel tank increases, forcing HC vapors from the tank. Excess 

emissions, exceeding the carbon canister’s capacity, are vented to the atmosphere. 

Figure 3 - Control System Schematic

Leaks can be liquid or vapor. Permeation and tank venting losses are strongly driven by fuel 

composition, ambient temperature, and ambient temperature change. Liquid leaks are not 

strongly affected by normal summer temperatures, and are thought to have two components:

1. Static leaks occurring while the engine is turned off and the vehicle is stationary

2. Increase in leak rate caused by the system pressure increase during engine operation.

A Test Method for Separating Permeation from Tank Venting and Leaks – In a previous

CRC Project (E-65), the canister loss was separated from the permeation measurement by 

venting the losses from the carbon canister outside 

the SHED. For Project E-77, the canister vent 

losses were collected and measured in a separate 

“trap canister” on a scale outside the SHED, as 

shown in Figure 4. This vent line was capped off

(i.e., sealed during the Static Test) but connected 

as shown in the figure for the Dynamic and the 

Diurnal Test. The ambient temperature in the 

SHED was constant during the static test, and 

there was no vapor created at constant 

temperature. 

Figure 4 - Trap Canister
7

This vent was closed to pressurize the system for the leak evaluations. The resulting SHED 

increase in HC mass was permeation7. The last mechanism that needed to be evaluated was 

leaks. Leaks can be both vapor and liquid. A liquid leak can have significant mass, currently 

undetected by the vehicle’s on-board diagnostic system. Considerable thought and effort have 

gone into the creation of a simple and effective liquid leak detection methodology, without 

success. The techniques used in this project required the use of a SHED for measurements. The 

techniques were not simple, but they proved effective.

Based on experience, a vehicle’s permeation rate is expected to be between the range of 4 to 90 

mg/hour at the 86°F test temperature. The presence of a static liquid leak is expected to 

overwhelm this value; such a leak would (or could) be apparent by inspection. Leaks from the 

vehicles were quantified in a three-step test process. The first step was to measure the static 

permeation rate of the vehicle at 86oF. The vehicle was allowed to stabilize overnight at 86oF in 

the SHED, and the permeation rate was calculated from the mass increase in the SHED during a 

one-hour measurement period. The second part of the test, looking for pressure driven leaks in 

the vapor system, was performed by pressurizing the vehicle’s tank to 5” H2O through a special 

fuel cap and tubing from outside the SHED (Figure 5). The special fuel cap, the hose, and the 

pressurization apparatus were installed before the start of the sequence. The HC concentration in 

the SHED was monitored, and the increase in the mass of HC in the SHED during the 30-minute 

pressurization period compared to the static permeation rate. If there was no (or insignificant) 

rate of increase, it was deduced that no vapor leak was present.

The third and final part of the test was to energize the vehicle’s fuel pump and pressurize the 

system up to and including the injectors (Figure 6). If there were a pressure leak in the liquid 

system, an increase in the SHED mass over the 30-minute measurement period would be seen, 

i.e., the leak would be additive to the permeation rate. 

 

6 This is a simplification. There are other HC sources present that are not fuel permeation. These include tire, paint, 

adhesives and vinyl emissions, and the possibility of fuel leaks from the fuel injectors. We believe these to be a 

minor component of the emissions measured in this study. 

Figure 5 - Static Test – Tank Pressurization
8

Figure 6 – Static Test – Fuel Pump Energized

Other Tests (Dynamic, Hot Soak, and Diurnal) - A similar configuration is used to isolate the 

tank venting losses from the permeation measurements determined by other test procedures. The 

vehicle’s canister vent is connected with a low permeation hose (TeflonTM) to a bulk-head fitting 

in the SHED wall and then to a separate “trap canister” on a top-loading scale. Any HC 

emissions that escape from the vehicle’s canister are captured in the trap canister and measured 

at a 0.01 g (10 milligram) precision. The trap canister (a 1 Liter Ford model) is purged before 

each test and maintained at a “dry” condition so that it captures all of the vehicle’s escaping 

emissions. This assumption is probably violated during the high volatility tests where there are 

30 grams of daily emissions, but this is not a concern at this time.

Test Elements for E-77-2 - The following flow chart (Figure 7) displays the various elements 

utilized during the testing of the various vehicles and fuels during this program. Details of each 

of the four basic tests follow the flow chart.
9

Drain and 40% Fill

with 10 psi E10 Test Fuel

Road Preconditioning

Four LA-4’s or Equivalent

Drain and 40% Fill

with 10psi E10 Test Fuel

Overnight Park at 86°F

Move to SHED

Connect Test Instrumentation

Stabilize at 86°F

Perform Constant Temperature 

Permeation Series (86°F)

1 hour Permeation Rate Test

1⁄2 hour Tank Pressurized Test

1⁄2 hour Pump Energized Test

Transfer to RL SHED

Connect Test Instrumentation

Stabilize at 86°F

Perform Dynamic Permeation Test

Two LA92 Driving Cycles &

One Hour Hot Soak

Drain and 40% Fill

With 10 psi E10 Test Fuel

Road Preconditioning

Four LA-4’s or Equivalent

Move to VT-SHED

Connect Test Instrumentation

Stabilize at 65°F for 6 hrs. Minimum 

Perform 3-Day Diurnal Evaluation

72 hr 65° to 105°F VT Test

Drain and 40% Fill

with 7 psi E10 Test Fuel

Condition Fuel System

By Driving for One Week

Repeat Steps 1 – 12

On 7 psi E10 Test Fuel

Drain and Fill with 9 psi E0 Test Fuel

Condition Fuel System by 4 weeks Driving

Repeat Steps 1 – 12

On 9 and 7 psi E0 and 

Repeat Steps 0-12

On 9 psi E20 Test Fuels

Precondition Fuel System

With 4 Weeks Driving on

10 psi E10 Test Fuel

1

2

3

4

5

6

7

8

9

10

11

12

0

Figure 7 – Testing Flow Chart
10

Test Procedures – There are four basic tests in the E-77-2 test protocol:

1. Static Permeation Rate (includes checks for vapor and liquid leaks)

2. Running Emissions (Dynamic Test)

3. Hot Soak

4. Diurnal

Each is described in detail below.

1. Static Permeation Rate Testing

The constant temperature (static) permeation rate is measured in a traditional SHED (Constant 

temperature) in the following manner.

A. The fuel tank is drained and filled to 40% tank capacity with the test fuel.

B. The day before testing, the vehicle is driven over four road trips of 7.5 miles each 

to precondition the canister.

8

(These drives are similar to the LA-4.)

C. Upon return from the road pre-conditioning, the fuel tank is drained and filled to 

40% tank capacity with the test fuel.

9

D. Vehicle is parked for 18-22 hours in a controlled temperature environment at test 

temperature (86oF).

E. The vehicle is then moved (without starting) into the test (86oF) SHED.

F. The canister vent is connected to the SHED bulkhead fitting which routes the 

vapor to the trap canister outside the SHED.

G. The tank system pressurization hose is connected.

H. The fuel pump electrical connection is connected.

I. The SHED is sealed, the inside temperature is allowed to stabilize and the test is 

started. Continuous THC measurements are made using a FID. Ethanol, 

methanol and R134a concentrations are measured using an INNOVA analyzer. 

All measurements are made at least every minute for one hour to determine the 

stabilized permeation rate.

J. At the end of the static test (60 minutes), the vehicle’s vapor system is pressurized 

to 5 inches of water for thirty minutes. Measurements are made to quantify vapor 

leaks as determined by a change in the THC in the SHED.

K. The fuel pump is then energized for 30 minutes while maintaining the 5 inches of 

water on the vapor system. Liquid leaks are quantified as determined by a change 

in the concentration of THC in the SHED.

The purpose of steps J and K above is to validate that the permeation rate measurement was 

made without the presence of any leak – either liquid or vapor. A detailed discussion follows, 

starting at page 12.

 

8

 This conditioning can be done in the laboratory on a chassis dynamometer if proper attention is paid to underbody 

cooling, and unrepresentative fuel tank temperatures are avoided.

9

 Vehicles with ORVR systems will add the refueling vapors to the canister. This is OK.
11

2. Running Loss Test (Dynamic Test)

A. The vehicle is placed in the RL-SHED and prepared for test. (The fuel level and 

condition for the dynamic test is the fuel remaining after completion of the static test –

40% fresh fill of the appropriate test fuel.)

B. Outside air source for the engine is connected.

C. Vehicle exhaust is connected.

D. Fuel tank thermocouple is connected.

E. Canister vent is connected to the SHED bulkhead fitting which routes the vapor to the 

trap canister outside the SHED.

F. Vehicle is allowed to stabilize in the RL-SHED at test temperature (86°F) for a minimum 

of 12 hours – preferably overnight.

G. Two cycles of the Unified Cycle (LA-92) driving schedule (48 mins.) are driven while 

measuring the mass emissions in the SHED. Vehicle is allowed to idle (in drive) for 30 

seconds between the two cycles. Ambient air temperature is maintained (to the extent 

possible) at 86°F. Fuel tank surface temperature is monitored during vehicle operation. It 

should increase during the drive from 10 to 18°F to simulate expected on-road 

temperature increase. Measured mass emissions are corrected using the INNOVA data 

for the ethanol, methanol, and refrigerant emissions.

3. Hot Soak10

This procedure is executed immediately following the Running Loss Test procedure 

described above.

A. Engine is turned off, transmission selector is placed in park, and driver exits the 

enclosure, using the double door air lock, taking care to minimize any air exchange 

between the laboratory and the SHED. This starts the one hour “hot soak” period.

B. Measurements of mass emissions in the SHED are continued for another 60 minutes 

(until time = 108 minutes), correcting for the ethanol, methanol, and refrigerant mass 

using the INNOVA instrument data. This ends the hot soak. Hot soak emissions are 

calculated as the net difference for the one hour hot soak (CorrMass108 – CorrMass48

minus the 86°F static hourly rate, all mass rates in mg/hour). 

4. Diurnal Test

A. The fuel tank is drained and filled to 40% tank capacity with the test fuel.

B. The day before testing, the vehicle is driven over four road trips of 7.5 miles each to 

precondition the vehicle and the canister.

C. Upon return from the road pre-conditioning, the fuel tank is drained and filled to 40% 

tank capacity with the test fuel.

D. The vehicle is parked for 18-22 hours in a controlled temperature environment at the 

initial diurnal test temperature (65oF).

E. The SHED is sealed, allowed to stabilize at the 65°F temperature and the 3-day 

California Diurnal Test is started. 

 

10

 We define the “hot soak” to be the temporary increase in emission rate caused by the immediately preceding 

operation of the vehicle. It is the increase in the SHED mass (corrected for EtOH, MeOH and R-134a) over the 

one hour period minus the previously established “static” permeation rate.
12

F. “Continuous” (every 30 seconds) THC measurements are made using a FID. Ethanol, 

methanol, and R134a (refrigerant) concentrations are measured using an INNOVA 

analyzer, at least every 10 minutes for the duration of the test (72 hours).

Static Permeation Test – Leak Validation 

If a leak is detected during either the vapor system pressure portion (Step J) or the pump 

energized portion (Step K) of the Static Permeation Test procedure, it calls into question whether 

the permeation rate measurement accurately reflects fuel system permeation or if instead a 

combination of permeation and the implied leak was measured. If a leak is confirmed, the 

permeation rate measurement is called into question, and an investigation, possible remedy, and 

retest is indicated.

The permeation rate measurement must be corrected for the FID’s ethanol misrepresentation, and 

the presence of non-fuel hydrocarbons (methanol and refrigerant). The leak check, however, is 

made using the change in mass increase in the SHED using the uncorrected FID mass calculation 

as the determinate. It was found that the corrections for ethanol, methanol, and refrigerant were 

introducing “noise” into the trace and that these were being misinterpreted as leaks. 

y = 0.62x - 1.9

y = 0.47x + 6.7

y = 0.55x - 0.1

0

10

20

30

40

50

60

70

80

90

100

0 20 40 60 80 100 120 SHED Mass - mg

Test Time - minutes

Leak Test

Vehicle 204 - 1999 Honda Accord - 9 psi E0

Test 7028

Tank Pressurized Pump Activated

Figure 8 above represents the calculations made during the inspection of data from a successful 

test. EXCEL’sTM “SLOPE” function is used to calculate the linear regression values based on 

the FID calculation for mass for: Time 0 to 60 minutes, Time 64 to 90 minutes, and Time 94 to 

120 minutes. A 4-minute gap was included between each sequence to establish the new mass 

emission rate during the “pressure on,” (T60 to T90), and the “pump energized” periods.

The slope of 0.47 for the “Tank Pressurized” period in the example above is compared to the 

slope of 0.62 calculated for the permeation rate (or hot soak) period. Since the “Tank 

Figure 8 – Leak Test
13

Pressurized” slope is not more than 10% higher than the hot soak permeation rate, we assume 

that there is no leak present. A similar comparison is made for the slope determined during the 

“pump on” period. The choice of a 10% allowance is arbitrary and is used here to allow for 

normal and unavoidable test variation.

For tests in which the above procedure determines that no leak is present, a value of zero is 

reported in the test summary for the leak results. If a positive value is reported, it calls that test 

into question, and an investigation, possible repair, and retest is indicated.

Static Permeation Rate Determination

The static permeation rate is determined based on a linear regression through the individual 

SHED mass data points (data measured each 30 seconds) of the corrected fuel results (corrected 

for the FID error, and subtracting the methanol and refrigerant) from the first 60 minutes of 

testing as illustrated in Figure 9 below.

y = 0.5636x + 0.505

0

5

10

15

20

25

30

35

40

45

0 10 20 30 40 50 60 Permeation - mgs.

Test Time - mins.

Static Permeation Determination

Vehicle 204 - 1999 Honda Accord - 9 psi E0 Fuel

Raw SHED 

Corrected Fuel

Permeation Rate Based on Corrected Results

Permeation Rate = .5636 x Time = 33.8 mgs/hr

In this example, the static permeation rate is 33.8 mg/hr.

Dynamic (Running Loss) and Hot Soak Test

The preceding section addressed the concepts of separating the permeation emissions from the 

tank venting emissions, and establishing the presence or absence of leaks. The second part of 

this study includes a dynamic test to measure the permeation and tank venting emissions during 

Figure 9 – Static Permeation Determination
14

vehicle operation (“running losses”) and the temporary condition following vehicle operation 

known as the “hot soak.”

This is considered a “dynamic” test because the vehicle is driven and the fuel and vapor system 

temperatures rise during the test. The ambient temperature in the Running Loss SHED during

the test was held constant at 86°F, while the vehicle’s fuel system temperature rose during the 

test. Two 1435 second (23.9-minute) LA-92 driving cycles were performed consecutively during 

the running loss measurements with a 30-second idle in-between. During this test, tank fuel 

temperature was expected to rise by an average approximately 18°F above the initial ambient 

temperature. The running loss air handling system included a proportional speed under-car 

blower operated as a slave to dynamometer speed. This apparatus was used during running loss 

testing with minor tuning for specific vehicles. Without additional input, it is capable of 

reasonable fuel tank temperature control. Each vehicle was fitted with a surface-mount 

thermocouple at the front of the fuel tank, located at approximately the 1/8th fill level to measure 

the fuel liquid temperature. No attempt was made to follow a predefined fuel tank temperature 

profile (FTTP) in this program. Fuel temperatures were recorded, and results are available in the 

real-time records. 

Vehicle running loss emissions are measured in a special version of a SHED known as a 

Running Loss SHED (RL-SHED), shown in Figure 10. Special features of the RL-SHED 

include a sealed chassis dynamometer for simulating vehicle driving loads, a sealed outside air 

supply for engine intake, a sealed exhaust conduit for engine exhaust, and an under-chassis fan 

for simulating underbody air flow as described above. A vehicle is operated inside the RL-SHED 

over a chosen driving cycle. The increase in HC emissions inside the enclosure are measured 

and calculated as mass emissions per 40 CFR §86.163-96. 

Figure 10 - Running Loss SHED
15

Vehicle testing in an RL-SHED is complicated by several factors, including:

1. Engine must be supplied with external induction air.

2. Exhaust must be conducted externally without any leaks.

3. Load supplied to the vehicle through the chassis dynamometer must not create or 

allow external leaks.

4. Internal SHED temperature must be maintained while sizable heat is rejected to the 

ambient by the running engine and exhaust.

5. Cooling air supplied to the radiator must be modulated to represent the vehicle’s road 

speed.

6. Underbody (and especially the fuel system) temperature should represent the rate of 

rise experienced by a real road-drive.

Canister vent losses were isolated from permeation emissions using the technique previously 

described. The vehicle’s carbon canister fresh air vent was connected to the outside of the RLSHED using a leak-tight PTFE®

hose (3/8” OD commercial tubing, US Plastics #58055 PTFE or 

equivalent) connected to a small carbon “trap” canister located on a top-loading precision scale. 

The scale precision was 0.01 grams (10 milligrams) and it was purged prior to each test. There 

were no tank venting emissions measured on any of the running loss test measurements. All of 

the vehicles appeared to be actively “purging” their respective control canisters and drawing 

fresh air during the test. If there were any emissions from the vehicle’s control canister, as might 

have occurred if there were no vehicle purge or if very high volatility fuels with excessive vapor 

generation were used, they would have been measured.

The Running Loss Driving Cycle consisted of two cycles of the “Unified Driving Cycle,” 

otherwise known as the LA-92. A velocity versus time plot for one cycle is shown in Figure 11.

The LA-92 cycle takes 24 minutes to complete, and covers 9.8 miles, with many speed changes. 

Two back-to-back cycles were driven, the first as a “cold start,” and the second following a 30-

second vehicle idle. The “cold start” condition was created by soaking the vehicle for a 

Figure 11 – Running Loss Driving Cycle

Unified Cycle (LA-92)

0

10

20

30

40

50

60

70

80

0 5 10 15 20 25

Test Time - minutes

Speed - mph

Cycle Time (min) 23.9

Maximum Speed (mph) 67.2

Average Speed (mph) 24.6

Average Non-Zero Speed (mph) 29.4

Time @ Zero Speed (%) 16.2

Distance (miles) 9.82
16

minimum of 18 hours at 86°F, moving it to the stabilized 86°F RL-SHED, making the test 

connections, and then waiting a minimum of one hour before the initial start and run.

The SHED emissions were measured during 48 minutes of engine operation, and then 

continuously for one hour after the engine was turned off. This one hour, engine-off duration 

was the “hot soak” period. The total test time is 1 hour and 48 minutes.

Figure 12 shows results from the 9 psi E0 fuel test on Vehicle 204. The horizontal axis is test 

time in minutes, and the vertical axis is the HC mass measured in the RL-SHED during the test 

period. 

The engine was shut off at the end of the second LA92 drive cycle (~48 minutes), and the 

analysis system continued to measure the HC emissions in the SHED for the next 60 minutes. 

This represented the “hot soak” portion of the test. 

0

50

100

150

200

250

300

0 20 40 60 80 100 120 Corrected Total Fuel Cumulative Permeation - mg

Test Time - minutes

Running Loss and Hot Soak

Vehicle 204 - 1999 Honda Accord - 9 psi E0 Fuel

Test 25668

Running Loss Hot Soak

Running Loss Std. =0.05 g/mi

This Test = 0.010 g/mi

 RL = 249 mg/hr

277.4

233.2

Tru HS = 44.2

199.0 

The “True” Hot Soak

The traditional hot soak is determined from the increase in SHED emissions as measured for one 

hour following a prescribed drive to heat up the vehicle (2 LA-92 cycles during the Running 

Loss Test). Hot soak emissions, however, have two components; that caused by the elevated 

temperature resulting from the drive, and that resulting from one hour of static permeation.

Figure 12 – Running Loss Test Results
17

To separate these two components and determine the “true” hot soak emissions, the following 

procedure was used. “Traditional” hot soak emissions were first calculated by subtracting the 

“start of hot soak” cumulative SHED hydrocarbon value (i.e., 199 mg @ t = 48 minutes) from 

the final cumulative SHED hydrocarbon value (i.e., 277.4 mg @ t = 108 min.). This resulted in a 

cumulative SHED hydrocarbon value of 78 mg for the 1 hour hot soak. The previously 

determined static permeation value (i.e., 33.8 mg for a 1 hour hot soak test- see Figure 9) was 

then subtracted to arrive at the “true” hot soak value of 44.2 mg. The increase in the permeation 

rate (the “hot soak effect”) caused by the increase in the system temperature is accounted for by 

subtracting the “stabilized permeation rate” at 86°F.

In Figure 12, the static permeation rate is superimposed as a solid blue line on the plot from the 

starting point of the hot soak until its end (one hour). While the “traditional” hot soak would be 

calculated as 78 mg (277 mg – 199 mg), the “true” hot soak is determined as 44.2 mg (277.4 mg 

– 233.2 mg). True hot soak values reported here were determined in this manner.

Diurnal Test

Diurnal permeation was determined by subjecting the vehicle to a three-day period in a 

temperature controlled SHED while continuously recording the total hydrocarbon every 30 

seconds. The SHED environmental temperature was varied from 65°F to 105°F per the 

California Diurnal Test protocol. Canister vent losses were isolated from permeation emissions 

using the technique previously described. The vehicle’s carbon canister fresh air vent was 

connected to the outside of the RL-SHED using a leak-tight PTFE®hose connected to a small 

carbon “trap” canister located on a top-loading precision scale. The scale precision was 0.01 

grams (10 milligrams), and it was purged before each test. 

DISCUSSION OF TEST RESULTS

Results

Emission results are presented below by “mechanism11,” with the data averaged for the five 

“enhanced” and the two “near zero” vehicles. The lone “pre-enhanced” vehicle, the 1996 Ford 

Taurus (202), was a special case and will be discussed in a separate section. Two of the vehicles, 

the 2001 Dodge Caravan (207), and the 2004 Toyota Camry (211) were also subjected to limited 

testing with an “implanted leak” (a 0.020” dia. hole in a special tank gas cap) to investigate the 

magnitude of a known leak. These results (“Leakers”) follow the discussion on the Taurus.

Static Permeation Rate (Constant Temperature (86°F)) - Average permeation rate compared 

by fuel specification for two vehicle groups; “enhanced” and the “near zero” evaporative 

emissions. 

 

11

 The “mechanisms” are; 1 Permeation, 2 Tank Venting (Daily Temperature Rise), and 3 Leaks.
18

0

10

20

30

40

50

60 Corrected Permeation Rate - mg/hr

Fuel

Static Permeation Rate - All Fuels

E77-2 Program Vehicles

7 E0 9 E0 7 E10 10 E10 9 E20 7 E0 9 E0 7 E10 10 E10 9 E20

Enhanced

(5 veh)

Near Zero

(2 veh)

Figure 13 presents the static permeation rate performance for the average of the 5 “enhanced” 

and 2 “near zero” vehicles on the five fuels included in the test program. Each group is ordered 

from left to right by ethanol level. The vertical scale is the average permeation rate in mg/hour 

for the static (86°F constant temperature) test.

Previous studies12,13 had shown that vehicles operated on the fuel containing 10 vol-% ethanol 

would have higher permeation rates compared to those resulting from operation on a non-ethanol 

(E0) fuel of similar properties. We also expected that vehicles using higher vapor pressure fuel 

would exhibit increased permeation levels at similar ethanol levels. Other studies had reported 

mixed results when comparing E20 permeation rates against E10 measurements – some were 

higher and some were lower. The difference may have been within the repeatability of the 

measurements, and probably suffered from a limited number of observations. These mixed 

results are present in this testing of the enhanced vehicles however, the E20 (violet bar) is higher 

on average for static permeation rate for the Near Zero group. The data that were used to 

construct the averages in Figure 13 are listed in Table 3 below. There is significant variability in 

the test results, and the limited sample size precludes making conclusive statements with 

statistical confidence.

 

12

 CRC E-65.3, Fuel Permeation from Automotive Systems: E0, E6, E10, E20 and E85, December 2006 

13

 CRC E-77, Vehicle Evaporative Emission Mechanisms: A Pilot Study, June 2008.

Figure 13 – Static Permeation Rate Comparison
19

Table 3

Vehicle ID Technology 7psi E0 9 psi E0 7 psi E10 10 psi E10 9 psi E20

204

1999 Honda Enhanced 12.9 33.8 66.4 84.3 55.3

Accord

205

2001 Toyota Enhanced 9.9 19.5 59.6 41.6 46.2

Corolla

207

2001 Dodge Enhanced 40.1 32.5 64.4 78.7 88.2

Caravan

214

2004 Ford Enhanced 25.2 10.7 23.9 24.4 16.8

Escape

215

2004 Toyota Enhanced 8.7 8.5 12.2 10.4 19.3

Highlander

19.4 21.0 45.3 47.9 45.2

211

2004 Toyota Near Zero 9.1 10.1 9.4 19.9 55.8

Camry XLE

212

2006 Ford Near Zero 0.9 3.2 21.8 10.6 4.7

Taurus

5.0 6.7 15.6 15.3 30.3

Static Permeation Rate - mg/hr

CRC E-77-2 Program - Static Permeation Results 

Enhanced Averages

Near Zero Averages

Summary – Static permeation rate increased with increase in ethanol level. Three of the 5 

enhanced emission vehicles did not show an increase in permeation rate when tested with the 9 

psi E0 compared to the 7 psi E0.
20

Dynamic (Running Loss) Permeation - In a similar presentation, Figure 14 shows the average 

“Running Loss” permeation rate for the vehicle types and the fuels tested. “Running Loss” 

permeation as described here is the permeation measured during a “cold start” 48 minute drive in 

a Running-Loss SHED (RL-SHED) at 86°F.

0

50

100

150

200

250

300

350

400

7E0 9E0 7E10 10E10 9E20 7E0 9E0 7E10 10E10 9E20

Corrected Running Loss Permeation - mg/hr

Fuel

Running Loss Permeation Rate - All Fuels

E77-2 Program Vehicles

Enhanced

(5 vehs)

Near Zero

(2 vehs)

The dynamic permeation rates for the enhanced vehicles (left panel) followed a similar pattern as 

the static permeation. The average of the E20 fuel was the highest of the average values 

observed on both the enhanced and the near-zero vehicles (left and right panels, respectively). 

Table 4 below shows the data used to generate the averages used in Figure 14.

Figure 14 – Running Loss Permeation Comparison
21

Table 4

Vehicle ID Technology 7psi E0 9 psi E0 7 psi E10 10 psi E10 9 psi E20

204

1999 Honda Enhanced 222.6 249.2 287.9 316.4 272.0

Accord

205

2001 Toyota Enhanced 67.1 103.1 232.8 191.6 169.7

Corolla

207

2001 Dodge Enhanced 842.5 833.9 812.2 858.1 1028.2

Caravan

214

2004 Ford Enhanced 36.3 96.7 105.7 133.1 139.4

Escape

215

2005 Toyota Enhanced 79.7 81.1 97.9 71.9 102.5

Highlander

249.6 272.8 307.3 314.2 342.4

211

2004 Toyota Near Zero 104.6 83.7 56.3 138.3 410.6

Camry XLE

212

2006 Ford Near Zero 184.5 115.8 201.2 148.9 116.8

Taurus

144.6 99.8 128.8 143.6 263.7

Enhanced Averages

Near Zero Averages

CRC E-77-2 Program - Running Loss Permeation Results 

Running Loss Permeation Rate - mg/hr

Summary – The dynamic permeation rate (measured during vehicle operation) was higher with 

the E10 fuel compared to E0 for the enhanced vehicles. The E20 permeation rate was higher 

than E0 and the E10 fuel. The small sample size and limited data precludes us from making 

statements about statistical confidence, but this may indicate a trend. The near zero vehicle 

average increased as the ethanol level increased. Trends with volatility were mixed, or 

inconclusive.
22

Hot Soak (“True Hot Soak”) Permeation – The Hot Soak emissions as defined in this report 

are the net increase in permeation rate following vehicle operation. We measured the mass 

increase in the SHED for one hour immediately following vehicle operation, and subtracted the 

previously measured static (or normal) permeation at the same temperature. While this is not the 

traditional Code of Federal Regulations (CFR) definition, we feel it is appropriate for the intent 

of this project.

0

10

20

30

40

50

60

70

7E0 9E0 7E10 10E10 9E20 7E0 9E0 7E10 10E10 9E20 Corrected Hot Soak Permeation - mg/hr

Fuel

"True" Hot Soak Permeation Rate - All Fuels

E77-2 Program Vehicles

Enhanced

(5 vehs)

Near Zero

(2 vehs)

The “True Hot Soak” performance for the average of the Enhanced Vehicles is summarized in 

Figure 15 above. There was a large increase in the hot soak value with the E10 fuel compared to 

the E0. The hot soak value with the E20 fuel was comparable to the E0 results, and lower than 

the E10.

The Near Zero vehicles (2) had zero hot soak emissions when tested on the 10 psi E10 fuel 

(Figure 16). With only two vehicles and the very low levels attained, no statistically significant 

conclusions can be drawn from the data available. Table 5 presents the individual tests used in 

calculating the average values plotted in Figure 15.

Figure 15 – True Hot Soak Permeation Comparison
23

Table 5

Vehicle ID Technology 7psi E0 9 psi E0 7 psi E10 10 psi E10 9 psi E20

204

1999 Honda Enhanced 18.7 44.3 29.7 0.4 13.4

Accord

205

2001 Toyota Enhanced 0.0 1.0 71.9 29.5 60.3

Corolla

207

2001 Dodge Enhanced 0.0 5.8 122.2 237.7 0.0

Caravan

214

2004 Ford Enhanced 3.3 52.1 32.9 57.4 56.0

Escape

215

2005 Toyota Enhanced 22.5 25.1 0.0 1.6 0.0

Highlander

8.9 25.7 51.3 65.3 25.9

211

2004 Toyota Near Zero 0.7 15.3 13.8 0.0 0.0

Camry XLE

212

2006 Ford Near Zero 1.8 0.4 0.0 0.0 4.9

Taurus

1.3 7.9 6.9 0.0 2.5

CRC E-77-2 Program - True Hot Soak Permeation Results 

True Hot Soak Permeation Rate - mg/hr

Near Zero Averages

Enhanced Averages

Summary - The True Hot Soak permeation (permeation rate measured following vehicle 

operation less the static constant temperature permeation rate) rate was higher with the E10 fuel 

compared to E0 for the enhanced vehicles. The E20 permeation rate was higher than E0 and 

lower than the E10 fuel. The near zero vehicle trends with both ethanol content and volatility 

were mixed, or inconclusive. The small sample size and limited data precludes us from making 

statements about statistical confidence. 
24

Diurnal Permeation Performance – Figure 16 presents the diurnal permeation results for the 

first day of the three-day diurnal test (65° to 105°F).

0

200

400

600

800

1000

1200

7E0 9E0 7E10 10E10 9E20 7E0 9E0 7E10 10E10 9E20 Corrected Fuel Diurnal Permeation - mgs/day

Day 1 Diurnal Permeation Rates Averages from E-77-2 Vehicles

Fuel

Enhanced

(5 vehs)

Near Zero

(2 vehs)

The average day 1 diurnal permeation for the five Enhanced Vehicles tended to increase as 

ethanol content increased (with the exception of the E20 fuel). Again, sample size and limited 

data makes statistical conclusions inappropriate. Table 6 presents the individual test used to 

generate the averages used in Figure 16. The table includes the data from days 2 and 3. The 

ethanol content of the diurnal measurements was calculated, and appear in a series of figures in 

the Appendix starting at page 37. Unlike Figure 16, the figures shown in the appendix have not 

been corrected to exclude the non-fuel emissions (methanol and refrigerant) that were present 

during these tests.

Figure 16 – Day 1 Diurnal Permeation Comparison
25

Table 6

Vehicle ID Technology 7psi E0 9 psi E0 7 psi E10 10 psi E10 9 psi E20

204 Day 1 367.2 628.3 1260.1 1547.9 1103.4

1999 Honda Enhanced Day 2 287.7 581.0 1165.2 1779.9 958.1

Accord Day 3 293.6 577.0 1165.3 1771.1 981.2

205 Day 1 383.0 499.5 1783.4 1794.1 1775.2

2001 Toyota Enhanced Day 2 365.4 481.0 1715.0 1730.9 1690.0

Corolla Day 3 367.0 507.2 1523.9 1741.7 1680.2

207 Day 1 397.5 406.4 1086.5 1406.4 1548.0

2001 Dodge Enhanced Day 2 302.6 337.3 812.0 1264.4 1370.2

Caravan Day 3 268.9 308.0 823.6 1223.7 1360.5

214 Day 1 494.3 455.9 524.2 492.0 470.9

2004 Ford Enhanced Day 2 319.0 358.5 397.4 839.4 440.0

Escape Day 3 281.5 1101.7 394.4 11373.8 751.8

215 Day 1 248.3 202.1 224.7 319.2 416.8

2004 Toyota Enhanced Day 2 294.1 165.9 231.7 260.2 414.8

Highlander Day 3 288.8 176.3 267.5 237.0 450.6

378.1 438.4 975.8 1111.9 1062.9

211 Day 1 207.1 130.3 243.8 337.0 284.0

2004 Toyota Near Zero Day 2 100.2 115.8 183.8 226.8 221.8

Camry XLE Day 3 87.4 100.6 184.3 217.9 203.4

212 Day 1 101.6 100.5 184.8 124.3 131.0

2006 Ford Near Zero Day 2 71.2 70.8 100.2 87.9 83.3

Taurus Day 3 57.0 57.4 75.8 102.8 75.0

154.4 115.4 214.3 230.7 207.5

CRC E-77-2 Program Results - Diurnal Permeation

Diurnal Permeation Rate - mg/day

Enhanced Averages

Near Zero Averages

Carbon Canister Breakthrough – Canister breakthrough is measured by the weight change 

recorded for the trap canister outside the SHED. It quantifies the amount of vapors that 

overwhelm the evaporative system storage canister. Figure 17 displays the breakthrough 

resulting from testing of 9 psi E0 fuel. Only four of seven vehicles exhibited breakthrough.

60 

65 

70 

75 

80 

85 

90 

95 

100 

105 

110 

0 

5 

10 

15 

20 

25 

30 

35 

40 

0 10 20 30 40 50 60 70

SHED Temperature - deg F Breakthrough - mg

Test Time - hrs.

Canister Breakthrough

9 psi E0 Fuel - 65o to 105o F Diurnal

204 - 1999 Honda Accord

211 - 2004 Toyota Camry

215 - 2004 Toyota Highlander

205 - 2001 Toyota Corolla

Figure 17 –Diurnal Canister Breakthrough
26

Table 7 shows the breakthrough generated during the diurnal tests conducted.

Table 7

Vehicle ID Technology 7psi E0 9 psi E0 7 psi E10 10 psi E10 9 psi E20

204 Day 1 --- 2.4 --- 31.0 ---

1999 Honda Enhanced Day 2 --- 13.6 --- 36.0 ---

Accord Day 3 --- 19.8 --- 36.0 ---

205 Day 1 --- --- --- 20.4 ---

2001 Toyota Enhanced Day 2 --- --- --- 30.9 ---

Corolla Day 3 --- 2.6 --- 29.3 ---

207 Day 1 --- --- --- --- ---

2001 Dodge Enhanced Day 2 --- --- --- --- ---

Caravan Day 3 --- --- --- --- ---

214 Day 1 --- --- --- --- ---

2004 Ford Enhanced Day 2 --- --- --- --- ---

Escape Day 3 --- --- --- 4.9 ---

215 Day 1 --- --- --- --- ---

2004 Toyota Enhanced Day 2 --- 0.2 --- --- ---

Highlander Day 3 --- 7.2 --- --- ---

211 Day 1 --- --- --- --- ---

2004 Toyota Near Zero Day 2 --- 12.9 --- 19.1 ---

Camry XLE Day 3 --- 17.6 --- 28.9 ---

212 Day 1 --- --- --- --- ---

2006 Ford Near Zero Day 2 --- --- --- --- ---

Taurus Day 3 --- --- --- 20.4 ---

CRC E-77-2 Program - Carbon Canister Diurnal Breakthrough Results 

Diurnal Breakthrough - grams

Summary – The lack of canister breakthrough for the 7 psi fuels (summer grade) indicates that 

the storage capacity of the seven systems tested is appropriately sized. Breakthrough began to 

appear when testing of 9 psi E0 fuel (not summer grade), and was more prevalent with the 10 psi 

E10 fuel (winter grade). The lack of breakthrough with the 9 psi E20 fuel seems to be an 

anomaly.
27

Overall Trend Summary - The following chart (Figure 18) visually summarizes the trends seen 

from all testing performed during this program.

Higher Volatility E0 to E10 E0 to E20 E10 to E20

↑ ↑ ↑ ↑

Higher Volatility E0 to E10 E0 to E20 E10 to E20

↑ ↑ ↑ ↑

Higher Volatility E0 to E10 E0 to E20 E10 to E20

↑ ↑ ↑ ↑

Higher Volatility E0 to E10 E0 to E20 E10 to E20

↑ ↑ ↑ ↑

Higher Volatility E0 to E10 E0 to E20 E10 to E20

↑↔ ↑ ↑ ↑

Higher Volatility E0 to E10 E0 to E20 E10 to E20

↑ ↑ ↑ ↑

Higher Volatility E0 to E10 E0 to E20 E10 to E20

↑ ↕ ↓ ↓

Higher Volatility E0 to E10 E0 to E20 E10 to E20

↑ ↑ ↑ ↔

Ethanol Content

Diurnal

Trend Analysis for E-77-2 Program

Ethanol Content

Static Permeation

Ethanol Content

Running Loss Permeation

Ethanol Content

Ethanol Content

Diurnal

Enhanced Vehicles (Sample of 5)

Static Permeation

Ethanol Content

Ethanol Content

Running Loss Permeation

Ethanol Content

True Hot Soak (TEFVO)

Near-Zero Vehicles (Sample of 2)

True Hot Soak (TEFVO)

Figure 18 Trend Analysis Summaries
28

Vehicle 202 – 1996 Ford Taurus - Special Case

We have treated vehicle 202 as a special case. This was the oldest of the vehicles tested, and had 

been subjected to limited exhaust emission tests with a 20-volume percent ethanol fuel (E20) 

during the CRC E-74b test program.

Vehicle 202 completed the E10 portion of the test program (10 and 7 psi fuels) successfully, and 

completed the road preconditioning on the E0 fuel prior to the E0 evaluations. The first test on 

the E0 fuel was excessively high, indicating a fuel leak. It was traced to a leaky fuel injector oring, and there was considerable discussion as to an appropriate repair. Tests were made on the 9 

and the 7 psi E0 fuel to measure the magnitude of a vehicle in a “leak” condition, and the tests 

were labeled as “202L (Leak).” The fuel injector o-rings were replaced as a complete set, and 

the vehicle resumed testing as “202R’ (Repaired). A new, elusive vapor leak was present, later 

identified as a very small leak at the top of the fuel fill pipe.

The circle on Figure 19 at the right shows 

the location of the small leak. This leak 

was problematic as to its effect on the 

emission measurements because its 

magnitude or presence seemed to depend 

on the torque exerted on the fuel cap. The 

tests on the E0 fuels (9 and 7 psi) are 

noted as 202R, but with a vapor leak.

We attempted to fix this leak, and repeated 

the E10 test with the vehicle re-identified 

as 216 with reasonable results. We also 

ran the E20 test sequence and declared the 

vehicle done. 

The testing history for this vehicle is shown in Tables 8 (Static), 9 (Dynamic), and 10 (Diurnal). 

The tests highlighted in yellow are those that exhibited a liquid or vapor leak as identified during 

the static test leak validation.

Figure 19 – Vehicle 202 Fuel Fill Pipe Leak
29

Table 8

Static Permeation Results

1996 Ford Taurus SHED

Corrected Results Canister

Fuel Permeation mg/day Loss

Veh psi/EtOH Test Type Date Test# mg/hr (Corrected) g

202 10.0/E10 Static Perm 07/18/07 7018 34.5 0.00

Press. Incr. 0.0 No Leak

Prs+Fuel Incr. 0.0

202 7.0/E10 Static Perm 08/21/07 7031 22.3 0.00

Press. Incr. 0.0 No Leak

Prs+Fuel Incr. 0.0

202L 9.0/E0 Static Perm 03/04/08 7169 229.2 0.00

Press. Incr. DNA

Prs+Fuel Incr. 492.1 Liquid Leak

202L 7.0/E0 Static Perm 03/20/08 7183 299.1 0.00

Press. Incr. DNA

Prs+Fuel Incr. 1989.6 Liquid Leak

202R 9.0/E0 Static Perm 05/08/08 7228 17.8 0.00

Press. Incr. 13.6 Vapor Leak

Prs+Fuel Incr. 0.0

202R 7.0/E0 Static Perm 05/22/08 7239 20.4 0.00

Press. Incr. 38.0 Vapor Leak

Prs+Fuel Incr. 0.0

216 10.0/E10 Static Perm 08/14/08 7299 32.4 0.00

Press. Incr. 0.0 No Leak

Prs+Fuel Incr. 0.0

216 7.0/E10 Static Perm 09/17/08 7326 32.5 0.00

Press. Incr. 0.0 No Leak

Prs+Fuel Incr. 0.0

216 9.0/E20 Static Perm 10/30/08 7363 20.4 0.00

Press. Incr. 0.0 No Leak

Prs+Fuel Incr. 0.0
30

Table 9

Dynamic Permeation Results

1996 Ford Taurus SHED

Corrected Results Canister From

Fuel Permeation mg/day Loss Static

Veh psi/EtOH Test Type Date Test# mg/hr (Corrected) g Test

202 10.0/E10 Dynamic RL 07/20/07 25662 127.8 0.00 No Leak

TEFVO 38.6 0.00

202L 9.0/E0 Dynamic RL 03/05/08 25695 387.0 0.00 Liquid Leak

TEFVO 0.0 0.00

202L 7.0/E0 Dynamic RL 03/24/08 25699 726.9 0.00 Liquid Leak

TEFVO 0.0 0.00

202R 9.0/E0 Dynamic RL 05/09/08 25704 109.1 0.00 Vapor Leak

TEFVO 5.0 0.00

202R 7.0/E0 Dynamic RL 05/23/08 25706 78.7 0.00 Vapor Leak

TEFVO 0.0 0.00

216 10.0/E10 Dynamic RL 08/15/08 25718 174.2 0.00 No Leak

TEFVO 1.4 0.00

216 7.0/E10 Dynamic RL 09/18/08 25721 168.3 0.00 No Leak

TEFVO 42.3 0.00

216 9.0/E20 Dynamic RL 11/07/08 25730 54.3 0.00 No Leak

TEFVO 0.0 0.00
31

Table 10

Diurnal Permeation Results

1996 Ford Taurus SHED

Corrected Results Canister From

Fuel Permeation mg/day Loss Static

Veh psi/EtOH Test Type Date Test# mg/hr (Corrected) g Test

202 10.0/E10 72 DHB 65-105 07/31/07 7023

Day 1 1042.9 6.12 No Leak

Day 2 706.9 32.64

Day 3 704.3 38.69

202 7.0/E10 72 DHB 65-105 08/28/07 7034

Day 1 627.8 0.00 No Leak

Day 2 506.5 0.00

Day 3 453.5 0.00

202L 9.0/E0 72 DHB 65-105 03/11/08 7173

Day 1 2258.9 0.00 Liquid Leak

Day 2 3231.0 0.00

Day 3 2306.9 12.60

202L 7.0/E0 72 DHB 65-105 04/01/08 7196

Day 1 4742.5 0.00 Liquid Leak

Day 2 4451.7 0.00

Day 3 3179.8 0.00

202R 9.0/E0 72 DHB 65-105 05/13/08 7230

Day 1 327.0 0.00 Vapor Leak

Day 2 266.7 0.00

Day 3 274.6 10.83

202R 7.0/E0 72 DHB 65-105 05/28/08 7243

Day 1 211.7 0.00 Vapor Leak

Day 2 220.8 0.00

Day 3 208.1 0.00

216 10.0/E10 72 DHB 65-105 08/20/08 7305

Day 1 2590.7 57.77 No Leak

Day 2 3477.9 62.99

Day 3 3601.4 63.43

216 7.0/E10 72 DHB 65-105 09/23/08 7331

Day 1 397.5 0.22 No Leak

Day 2 355.0 0.06

Day 3 362.1 0.37

216 9.0/E20 72 DHB 65-105 11/11/08 7373

Day 1 468.5 0.00 No Leak

Day 2 452.6 0.00

Day 3 419.8 0.00
32

The Implanted Leak Test Results

Project E-77-2 included evaluating two vehicles with implanted leaks. This interest followed the 

information gathered in the Pilot Study where tests were run with a specially modified fuel cap 

containing a 0.02” dia. hole. The results with the implanted leak from the Pilot Study are 

repeated in Table 11 below as the diurnal results are shown for a 1996 Chevrolet Cavalier; first 

without the implanted leak at 0.38 grams per day, and then at 20.7 grams per day (a 54x 

increase) with the leak.

Table 11

Veh. No.

Evap

Tech Fuel

Results

gms/day

gms

Increase

6 1996 Chevrolet Cavalier Enhanced 7 psi E0 0.38

7* " " " 20.70 20.32

207 2001 Dodge Caravan Enhanced 7 psi E10 1.09

207L* " " " 2.13 1.04

211 2004 Toyota Camry LE Near Zero 7 psi E10 0.24

211L* " " " 0.68 0.44

* - Implanted .020" leak in fuel cap

Vehicle Description

Implanted Leak Impact on Diurnal Permeation

Day One Results : 65° - 105°F Diurnal

The two E-77-2 vehicles (207 & 211) were given a limited evaluation with an induced leak and 

saw a significantly lesser impact. Vehicle 207 gave diurnal results increases from 1.09 to 2.13 

grams per day (a 2x increase), and Vehicle 211 increased from 0.24 grams per day to 0.68 grams 

per day (a 2.8x increase). The following Figure 20 displays the imbedded leak impact from Table 

11.
33

0

5

10

15

20 One Day Diurnal Permeation - gms/day

Vehicle Number

Implanted Leak Impact on One Day Diurnal Permeation

.020" Leak in Fuel Cap - 65 to 105 F Diurnal

6 7 207 207L 211 211L

As Received - No Leak

.020" Fuel Cap Leak

The newer vehicles evaluated in this phase of the study were configured and certified to the 

Onboard Refueling Vapor Regulations (ORVR). These are capable of containing 95% or more 

control of the refueling vapors at up to 10 gallons per minute fueling rate. Where the Chevrolet 

Cavalier had a small (0.055” dia.) orifice and a long vapor tube venting the tank’s vapor space to 

the carbon canister (and then to the atmosphere), the ORVR compliant vehicles have a large 

(0.688” ID), short vent hose to a low flow restriction carbon canister. 

The following bar charts (Figures 21 through 24) show the impacts of the leak on all phases of 

the evaporative testing performed, and compare those results with all fuels tested. With only two 

vehicles (207 and 211) evaluated on two fuels, statistically significant effects cannot be 

quantified, but the trend of increased emissions is apparent.

Figure 20 – Implanted Leak Impact
34

0

20

40

60

80

100

120

140

160

7E0 9E0 7E10 10E10 9E20 7E0 9E0 7E10 10E10 9E20 Static Permeation - mg/hr

Fuel

0.020" dia. Induced Leak Effect

Static Permeation

Vehicle 207 Vehicle 211

Leak

Leak

0

200

400

600

800

1000

1200

7E0 9E0 7E10 10E10 9E20 7E0 9E0 7E10 10E10 9E20

Running Loss Permeation - mg/hr

Fuel

0.020" dia. Induced Leak Effect

Running Loss Permeation

Vehicle 207 Vehicle 211

Leak

Leak

Figure 21 – Vehicles 207 and 211 with Induced Leak - Static

Figure 22 – Vehicles 207 and 211with Induced Leak – Running Loss
35

0

100

200

300

400

500

600

700

7E0 9E0 7E10 10E10 9E20 7E0 9E0 7E10 10E10 9E20 True Hot Soak Permeation - mg/hr

Fuel

0.020" dia. Induced Leak Effect

True Hot Soak Permeation

Vehicle 207 Vehicle 211

Leak

Leak

0

500

1000

1500

2000

2500

7E0 9E0 7E10 10E10 9E20 7E0 9E0 7E10 10E10 9E20

Day 1 Diurnal Permeation - mg/day

Fuel

0.020" dia. Induced Leak Effect

Day 1 Diurnal Permeation

Vehicle 207 Vehicle 211

Leak

Leak

Figure 24 – Vehicles 207 and 211 with Induced Leak - Diurnal

Figure 23 – Vehicles 207 and 211 with Induced Leak – True Hot Soak
36

Summary of Findings and Results

The E-77-2 test program was a continuation of the previously published E-77 test project, and 

added eight vehicles tested on five fuels to the knowledge base. The permeation trends 

previously shown were again present. The small sample size and limited number of tests 

preclude making statements about statistical validity, but in general:

o The newer vehicle groups had lower emissions.

o Adding ethanol to the fuel increased permeation over the non-oxygenated levels.

o Increased volatility increased permeation levels.

o SHED emission rates must be corrected for the ethanol error in the FID, and the 

non-fuel methanol and refrigerant in the measurement.

As this test program evolved and additional experience was gathered, two program modifications 

were made: 1) The leak validation methodology was changed, and 2) a different metric and 

definition of the “Hot Soak” was adopted.

The leak validation portion of the static permeation test was found to be very sensitive, and when 

the data was corrected on a minute-by-minute basis for ethanol, methanol, and refrigerant, the 

change in apparent permeation rate was due as much to variation as to leaks. See the discussion 

starting at page 12 for the details of the development.

Concern for and recognition of “Hot Soak” emissions started in the original evaporative emission 

regulations. Carburetors had float bowls with ~ 50 ml of fuel that absorbed the latent engine heat 

after the vehicle was shut down after operation. The heat would cause the bowl temperature to 

increase, driving fuel vapors out through vents and leak paths to the atmosphere after vehicle 

operation. Today’s fuel injection engines do not have the open bowls, and the emission rates 

following vehicle operation are mainly increased temperature permeation. We recommended 

and adopted a new name for the “temporary emissions following vehicle operation” (TEFVO), 

which subtracts the basic permeation rate from the measured emissions. See the discussion 

starting at page 16 for details. 
37

Appendix

Acknowledgements

E-77-2 Steering Committee

David Brzezinski..................EPA

Kevin Cullen ........................GM Powertrain

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

King D. Eng .........................Shell Global Solutions

Ben Hancock........................CARB

Constance Hart.....................EPA

Phil Heirigs..........................Chevron Global Downstream

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

Keith Knoll...........................NREL

John Koupal .........................EPA

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

Jeff Long ..............................CARB

Hector Maldonado ...............CARB

Mani Natarajan.....................Marathon Oil Company

David N. Patterson...............Mitsubishi Motors R&D Americas

Jenny Sigelko.......................Chrysler

James P. Uihlein...................Chevron Global Downstream

Marie Valentine ...................Toyota Technical Center

Kenneth J. Wright ................ConocoPhillips

CRC Members

Brent Bailey .........................CRC

Chris Tennant.......................CRC

Jane Beck ..........................CRC
38

Table 12

E0 E10 E20

Inspection Units Fuel 6 Fuel 7 Fuel 4

API Gravity °API 60.2 58.5 57.0

Relative Density 60/60°F 0.7382 0.7447 0.7508

DVPE psi 7.01 7.30 8.49

Oxygenates--D4815

MTBE vol % 0.00 0.00 0.00

ETBE vol % 0.00 0.00 0.00

EtOH vol % 0.00 9.54 20.34

O2 wt % 0.00 3.53 7.47

Hydrocarbon Composition

 Aromatics vol % 22.1 24.4 10.8

 Olefins vol % 8.0 8.8 5.5

 Saturates vol % 70.0 57.3 23.4

D86 Distillation

 IBP °F 97.4 104.0 102.2

 5% Evaporated °F 131.6 128.0 125.2

 10% Evaporated °F 142.3 133.0 131.4

 20% Evaporated °F 156.4 141.0 141.3

 30% Evaporated °F 170.4 145.0 148.6

 40% Evaporated °F 184.0 153.0 154.7

 50% Evaporated °F 197.5 195.0 159.6

 60% Evaporated °F 212.0 219.0 163.6

 70% Evaporated °F 230.5 241.0 227.4

 80% Evaporated °F 258.8 271.0 269.5

 90% Evaporated °F 313.9 317.0 313.9

 95% Evaporated °F 332.2 330.0 325.5

 EP °F 360.3 360.0 340.6

Recovery vol % 97.8 97.8 98.3

Residue vol % 1.3 1.0 1.0

Loss vol % 0.9 1.2 0.7

Driveability Index 1119.9 1101.5 989.8

Data from CRC E-74

CRC E-77-2 Fuel Inspection Results
39

Fuel Units Fuel 6 Fuel 7 Fuel 4

Sulfur Content ppm 29 27 27

Estimated C/H Ratio 6.2090 6.3323 6.3252

Est. Net Heat of Combustion btu/lb 18573 18514 18513

Benzene vol % 0.90 1.00 0.96

Research Octane Number 93.2 94.0 94.6

Motor Octane Number 83.8 83.8 83.4

(R+M)/2 88.5 88.9 89.0

Fuel Units Fuel 6 Fuel 7 Fuel 4

Aromatics vol % 23.86 24.81 21.78

Olefins vol % 7.52 8.92 10.74

Saturates vol % 67.43 56.21 46.23

Unclassified vol % 1.15 0.86 0.15

Ethanol vol % 0.00 9.20 21.11

Benzene vol % 0.89 1.06 0.97

C/H Ratio 6.200 6.092 5.835

Oxygen wt. % 0.008 1 3.40 7.73

Net Heat of Combustion btu/lb 18,703 18,016 17,160

1

 Contains 0.04 vol % MTBE

Fuel Units Fuel 6 Fuel 7 Fuel 4

Oxygen wt. % 0.008 3.396 7.733

C+H wt. % 99.99 96.60 92.27

H wt. % 13.89 13.62 13.50

C wt. % 86.10 82.98 78.77

Fuel Units 6 7 4

Haltermann D3338 Btu/lb 18,573 18,514 18,513

Average D3338 Btu/lb 18,579 18,514 18,491

Oxygen Corrected D3338 Btu/lb 18,579 17,860 17,103

DHA Btu/lb 18,703 18,016 17,160

Table 12 (cont.)

Suppliers Additional Inspections

Net Heat of Combusion -- Btu/lb

Carbon, Hydrogen, and Oxygen

Detailed Hydrocarbon Analysis
40

Vehicle Day 1 Day 2 Day 3

No. Fuel Base + Press + Pump RL "True" HS Perm (Brkthru) Perm (Brkthru) Perm (Brkthru)

E10 - 10 psi 34.5 --- --- 127.8 50.3 1042.9 (6.3) 706.9 (34.8) 704.3 (42.5)

E10 - 7 psi 22.3 --- --- 99.4 11.3 627.8 (0.0) 506.5 (0.0) 453.5 (0.0)

E0 - 9 psi 222.9 --- 492.1 387.0 0.0 2258.0 (0.0) 3231.0 (0.0) 2306.9 (12.6)

E0 - 7 psi 299.1 --- 1989.6 726.9 0.0 4742.5 (0.0) 4451.7 (0.0) 3179.8 (0.0)

E10 - 10 psi 84.3 --- --- 316.4 0.4 1547.9 (31.0) 1779.9 (38.3) 1771.1 (41.9)

E10 - 7 psi 66.4 --- --- 287.9 29.7 1260.1 (0.0) 1165.2 (0.0) 1165.3 (0.0)

E0 - 9 psi 33.8 --- --- 249.2 44.3 628.3 (2.4) 581.0 (13.6) 577.0 (22.5)

E0 - 7 psi 12.9 --- --- 222.6 18.7 367.2 (0.0) 287.7 (0.0) 293.6 (0.0)

E20 - 9 psi 55.3 --- --- 272.0 13.4 1103.4 (0.0) 958.1 (0.0) 981.2 (0.0)

E10 - 10 psi 41.6 --- --- 191.6 29.5 1794.1 (20.4) 1730.9 (34.6) 1741.7 (37.5)

E10 - 7 psi 59.6 --- --- 232.8 71.9 1783.4 (0.0) 1715.0 (0.0) 1523.9 (0.0)

E0 - 9 psi 19.5 --- --- 103.1 1.0 499.5 (0.0) 481.0 (0.0) 507.2 (2.6)

E0 - 7 psi 9.9 --- --- 67.1 0.0 383.0 (0.0) 365.4 (0.0) 367.0 (0.0)

E20 - 9 psi 46.2 --- --- 169.7 60.3 1775.2 (0.0) 1690.0 (0.0) 1680.2 (0.0)

E10 - 10 psi 78.7 --- --- 858.1 237.7 1406.4 (0.0) 1264.4 (0.0) 1223.7 (0.0)

E10 - 7 psi 64.4 --- --- 812.2 122.2 1086.5 (0.0) 812.0 (0.0) 823.6 (0.0)

E0 - 9 psi 32.5 --- --- 833.9 5.8 406.4 (0.0) 337.3 (0.0) 308.0 (0.0)

E0 - 7 psi 40.1 --- --- 842.5 0.0 397.5 (0.0) 302.6 (0.0) 268.9 (0.0)

E20 - 9 psi 88.2 --- --- 1028.2 0.0 1548.0 (0.0) 1370.2 (0.0) 1360.5 (0.0)

E10 - 10 psi 97.6 --- 120.9 1001.2 392.9 1644.9 (0.0) NA NA

E10 - 7 psi 146.8 --- --- 1139.3 585.0 2134.2 (0.0) NA NA

E10 - 10 psi 19.9 --- --- 138.3 0.0 337.0 (0.0) 226.8 (19.1) 217.9 (33.0)

E10 - 7 psi 9.4 26.6 --- 56.3 13.8 243.8 (0.0) 183.8 (0.0) 184.3 (0.0)

E0 - 9 psi 10.1 --- --- 83.7 15.3 130.3 (0.0) 115.8 (12.9) 100.6 (22.1)

E0 - 7 psi 9.1 --- --- 104.6 0.7 207.1 (0.0) 100.2 (0.0) 87.4 (0.0)

E20 - 9 psi 55.8 --- --- 410.6 0.0 284.0 (0.0) 221.8 (0.0) 203.4 (0.0)

E10 - 10 psi 55.1 --- 82.1 302.4 245.0 2545.4 (0.40) NA NA

E10 - 7 psi 48.1 --- 166.4 251.1 6.2 678.3 (0.0) NA NA

E10 - 10 psi 10.6 --- --- 148.9 0.0 124.3 (0.0) 87.9 (0.0) 102.8 (20.0)

E10 - 7 psi 21.8 --- --- 201.2 0.0 184.8 (0.0) 100.2 (0.0) 75.8 (0.0)

E0 - 9 psi 3.2 --- --- 115.8 0.4 100.5 (0.0) 70.8 (0.0) 57.4 (0.0)

E0 - 7 psi 0.9 --- --- 184.5 1.8 101.6 (0.0) 71.2 (0.0) 57.0 (0.0)

E20 - 9 psi 4.7 --- --- 116.8 4.9 131.0 (0.0) 83.3 (0.0) 75.0 (0.0)

E10 - 10 psi 24.4 --- --- 133.1 57.4 492.0 (0.0) 839.4 (0.0) 11373.8 (4.9)

E10 - 7 psi 23.9 --- --- 105.7 32.9 524.2 (0.0) 397.4 (0.0) 394.4 (0.0)

E0 - 9 psi 10.7 --- --- 96.7 52.1 455.9 (0.0) 358.5 (0.0) 1101.7 (0.0)

E0 - 7 psi 25.2 --- --- 36.3 3.3 494.3 (0.0) 319.0 (0.0) 281.5 (0.0)

E20 - 9 psi 16.8 --- --- 139.4 56.0 470.9 (0.0) 440.0 (0.0) 751.8 (0.0)

E10 - 10 psi 10.4 9.0 --- 71.9 1.6 319.2 (0.0) 260.2 (0.0) 237.0 (0.0)

E10 - 7 psi 12.2 --- --- 97.9 0.0 224.7 (0.0) 231.7 (0.0) 267.5 (0.0)

E0 - 9 psi 8.5 --- --- 81.1 25.1 202.1 (0.0) 165.9 (.2) 176.3 (7.2)

E0 - 7 psi 8.7 --- --- 79.7 22.5 248.3 (0.0) 294.1 (0.0) 288.8 (0.0)

E20 - 9 psi 19.3 --- --- 102.5 0.0 416.8 (0.0) 414.8 (0.0) 450.6 (0.0)

E10 - 10 psi 32.4 --- --- 174.2 11.8 2590.7 (57.8) 3477.9 (63.0) 3601.4 (64.3)

E10 - 7 psi 32.5 --- --- 168.3 19.2 397.5 (0.2) 355.0 (0.1) 362.1 (0.4)

E0 - 9 psi 17.8 13.6 --- 109.1 25.4 327.0 (0.0) 266.7 (0.0) 274.6 (10.8)

E0 - 7 psi 20.4 38.0 --- 78.7 0.0 211.7 (0.0) 220.8 (0.0) 208.1 (0.0)

E20 - 9 psi 20.4 --- --- 54.3 7.4 468.5 (0.0) 452.6 (0.0) 419.8 (0.0)

216

211

2004

Toyota

Camry 

XLE

215

2004

Toyota

Highlander

212

2006 

Ford

Taurus

214

2004 

Ford

Escape

211L

207L

Static Permeation - mg/hr Dynamic Perm. - mg/hr

CRC E-77-2 Program Test Results

Diurnal (65o to 105o) - mg/day

202

1996

Taurus

205

2001 

Toyota

Corolla

204

1999 

Honda

Accord

207

2001 

Dodge

Caravan

202L

Table 13 
41

Individual Vehicle Diurnal Performance on the Various Fuels

0

1000

2000

3000

4000

5000

6000

0 10 20 30 40 50 60 70 Cumulative Permeation - mg.

Test Time - hrs.

Three Day Diurnal

Vehicle 204 1999 Honda Accord

10 psi E10

7 psi E10

9 psi E0

7 psi E0

9 psi E20

0

1000

2000

3000

4000

5000

6000

0 10 20 30 40 50 60 70 Cumulative Permeation - mg.

Test Time - hrs.

Three Day Diurnal

Vehicle 205 - 2001 Toyota Corolla

10 psi E10

7 psi E10

9 psi E0

7 psi E0

9 psi E20

Figure 25 – Vehicle 204 Diurnal Performance

Figure 26 – Vehicle 205 Diurnal Performance
42

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

0 10 20 30 40 50 60 70 Cumulative Corrected Permeation - mg.

Test Time - hrs.

Three Day Diurnal

Vehicle 207 - 2001 Dodge Caravan

10 psi E10

7 psi E10

9 psi E0

7 psi E0

9 psi E20

0

100

200

300

400

500

600

700

800

900

0 10 20 30 40 50 60 70 Cumulative Permeation - mg.

Test Time - hrs.

Three Day Diurnal

Vehicle 211 - 2004 Toyota Camry XLE

10 psi E10

7 psi E10

9 psi E0

7 psi E0

9 psi E20

Figure 27 – Vehicle 207 Diurnal Performance

Figure 28 – Vehicle 211 Diurnal Performance
43

0

50

100

150

200

250

300

350

400

450

500

0 10 20 30 40 50 60 70 Cumulative Permeation - mg.

Test Time - hrs.

Three Day Diurnal

Vehicle 212 - 2006 Ford Taurus

10 psi E10

7 psi E10

9 psi E0

7 psi E0

9 psi E20

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

0 10 20 30 40 50 60 70 Cumulative Permeation - mg.

Test Time - hrs.

Three Day Diurnal

Vehicle 214 2004 Ford Escape

10 psi E10

7 psi E10

9 psi E0

7 psi E0

9 psi E20

Note: The incomplete cumulative results for the 10 psi E10 results resulted from a conflict for the use 

of the INNOVA analyzer during the test. The INNOVA analyzer is required to correct for the FID’s 

ethanol error, and the presence of methanol and refrigerant (R-134a). The data was available for the 

50+ hour results, and the data is valid as shown. We have no explanation for the high levels 

experienced on the third day of the test. No test errors were identified.

Figure 29 – Vehicle 212 Diurnal Performance

Figure 30 – Vehicle 214 Diurnal Performance
44

0

200

400

600

800

1000

1200

1400

1600

0 10 20 30 40 50 60 70 Cumulative Permeation - mg.

Test Time - hrs.

Three Day Diurnal

Vehicle 215 2004 Toyota Highlander

10 psi E10

7 psi E10

9 psi E0

7 psi E0

9 psi E20

Figure 31 – Vehicle 215 Diurnal Performance
45

Table 14

Test Corrected

Vehicle Fuel Total Fuel EtOH R134a Methanol

204 10 psi E10 5098.99 1440.40 182.98 167.54

1999 Honda 7 psi E10 3590.57 1308.06 175.51 152.21

Accord 9 psi E0 1786.35 138.43 182.30 98.96

7 psi E0 948.46 18.56 166.31 23.79

9 psi E20 3042.71 1284.08 182.61 121.43

205 10 psi E10 5266.59 1865.99 233.54 208.95

2001 Toyota 7 psi E10 5022.29 2042.46 259.90 191.98

Corolla 9 psi E0 1487.75 0.00 204.34 46.13

7 psi E0 1115.36 54.89 224.08 56.19

9 psi E20 5145.40 2127.08 256.77 195.84

207 10 psi E10 3894.50 1962.48 120.13 303.99

2001 Dodge 7 psi E10 2722.01 1140.27 117.31 196.16

Caravan 9 psi E0 1051.67 18.20 122.24 152.84

7 psi E0 969.06 11.18 221.41 142.76

9 psi E20 4278.82 2414.88 142.68 254.32

211 10 psi E10 781.64 197.33 151.59 469.70

2004 Toyota 7 psi E10 611.90 202.11 159.29 465.25

Camry LE 9 psi E0 346.68 16.81 143.29 426.59

7 psi E0 394.68 0.00 161.97 573.03

9 psi E20 710.13 267.26 162.13 368.79

212 10 psi E10 315.08 72.22 148.31 78.96

2006 Ford 7 psi E10 360.79 101.32 154.81 34.00

Taurus 9 psi E0 228.70 24.09 151.82 37.61

7 psi E0 229.73 0.00 153.93 43.62

9 psi E20 289.35 111.56 141.16 26.29

214 10 psi E10 12578.87 0.00 199.47 279.92

2004 Ford 7 psi E10 1315.93 245.71 160.25 88.79

Escape 9 psi E0 1916.11 29.40 164.87 72.13

7 psi E0 1094.81 53.86 806.50 31.06

9 psi E20 1662.71 240.97 144.91 60.96

215 10 psi E10 816.44 121.78 146.58 426.09

2004 Toyota 7 psi E10 723.99 150.92 155.32 360.61

Highlander 9 psi E0 544.31 0.00 148.06 258.22

7 psi E0 831.15 0.00 140.72 262.55

9 psi E20 1282.23 388.22 128.41 344.20

3 Day Diurnal Results

CRC E77-2 Program Diurnal Results

All values are in mg
46

0

200

400

600

800

1000

1200

1400

1600

1800

2000

Corrected Daily Diurnal - mg

Diurnal Ethanol Portion

Vehicle 204 - 1999 Honda Accord

Ethanol Portion

10 psi E10 7 psi E10 9 psi E0

1 2 3

31.5%

36.8% 34.1%

38.3%

27.3% 26.4%

1 2 3 1 2 3 1 2 3 1 2 3

7 psi E0 9 psi E20

11.2%

9.7% 2.0%

3.9%

1.0% 0.5%

44.2%

40.5% 41.2%

Figure 32 – Vehicle 204 Diurnal Ethanol Portion

0

200

400

600

800

1000

1200

1400

1600

1800

2000

Corrected Daily Diurnal - mg

Diurnal Ethanol Portion

Vehicle 205 - 2001 Toyota Corolla

Ethanol Portion

10 psi E10 7 psi E10 9 psi E0

1 2 3

35.9%

40.6%

38.2%

43.1%

34.9% 35.5%

1 2 3 1 2 3 1 2 3 1 2 3

7 psi E0 9 psi E20

0% 0% 0%

7.1% 4.9% 2.6%

40.6%

41.4% 42.0%

Figure 33 – Vehicle 205 Diurnal Ethanol Portion
47

0

200

400

600

800

1000

1200

1400

1600

Corrected Daily Diurnal - mg

Diurnal Ethanol Portion

Vehicle 207 - 2001 Dodge Caravan

Ethanol Portion

10 psi E10 7 psi E10 9 psi E0

1 2 3

48.8%

44.2% 40.8%

40.9%

49.0%

53.5%

1 2 3 1 2 3 1 2 3 1 2 3

7 psi E0 9 psi E20

0.0%

1.1%

4.4%

2.7%

0.1%

0.1%

55.6%

55.2% 58.7%

Figure 34 – Vehicle 207 Diurnal Ethanol Portion

0

50

100

150

200

250

300

350

400

Corrected Daily Diurnal - mg

Diurnal Ethanol Portion

Vehicle 211 - 2004 Toyota Camry XLE

Ethanol Portion

10 psi E10 7 psi E10 9 psi E0

1 2 3

26.4%

24.2%

24.5%

1 2 3 1 2 3 1 2 3 1 2 3

7 psi E0 9 psi E20

32.9%

35.6% 30.6%

0.0%

7.3%

6.4%

0.0%

0.0%

0.0%

32.5%

43.1%

37.0%

Figure 35 – Vehicle 211 Diurnal Ethanol Portion
48

0

20

40

60

80

100

120

140

160

180

200

Corrected Daily Diurnal - mg

Diurnal Ethanol Portion

Vehicle 212 - 2006 Ford Taurus

Ethanol Portion

10 psi E10 7 psi E10 9 psi E0

1 2 3

21.6%

17.0%

31.6%

1 2 3 1 2 3 1 2 3 1 2 3

7 psi E0 9 psi E20

19.4%

28.8%

43.6% 10.2%

10.5%

8.5%

0.0%

0.0%

0.0%

47.6%

52.9%

24.3%

Figure 36 – Vehicle 212 Diurnal Ethanol Portion

0

200

400

600

800

1000

1200

Corrected Daily Diurnal - mg

Diurnal Ethanol Portion

Vehicle 214 - 2004 Ford Escape

Ethanol Portion

10 psi E10 7 psi E10 9 psi E0

1 2 3

0.0%

1 2 3 1 2 3 1 2 3 1 2 3

7 psi E0 9 psi E20

20.1

15.2 20.2%

3.8%

0.5%

1.9%

5.6%

1.4%

6.9%

10.3%

17.1%

18.8%

14.3%

6.7%

11275

Figure 37 – Vehicle 214 Diurnal Ethanol Portion
49

0

50

100

150

200

250

300

350

400

450

500

Corrected Daily Diurnal - mg

Diurnal Ethanol Portion

Vehicle 215 - 2004 Toyota Highlander

Ethanol Portion

10 psi E10 7 psi E10 9 psi E0

1 2 3

12.1%

13.6%

19.6%

1 2 3 1 2 3 1 2 3 1 2 3

7 psi E0 9 psi E20

19.8%

21.3% 21.7%

0.0%

0.0%

0.0%

0.0% 0.0%

0.0%

33.5% 29.2%

28.3%

Figure 38 – Vehicle 215 Diurnal Ethanol Portion