## COORDINATING RESEARCH COUNCIL, INC.

3650 MANSELL ROAD · SUITE 140 · ALPHARETTA, GA 30022 

# CRC Report No. E-77



# Vehicle Evaporative
Emission Mechanisms:

A Pilot Study

June 24, 2008The Coordinating Research Council, Inc. (CRC) is a non-profit corporation supported by the petroleum and automotive equipment industries. CRC op erates 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 (atmosph eric and engineering studies); aviation fuels, lubricants, a nd equipment performance, heavyduty 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 det ermining the optimum combination of petroleum products and automo tive equipment. CRC’s work
is limited to research that is mutually beneficial to the two industries involved, and all inform ation 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 fo r infringement of patents.

### A Report on



# Vehicle Evaporative Emission Mechanisms: A Pilot Study

CRC Project E-77

June 24, 2008

Submitted by

Harold M. Haskew PE

Thomas F. Liberty Harold Haskew & Associates, Inc. Milford, Michiganii Acronyms

ATL............... Automotive Testing Laboratories CRC............... Coordinating Research Council, Inc.
FID ................ Flame Ionization Detector HC ................ Hydrocarbon
HH&A........... Harold Haskew & Associates LA-92 ............ Unified Driving Cycle MTBE............ Methyl Tertiary Butyl Ether
NBR .............. Nitrile Rubber or Ac rylonitrile Butadiene Rubber PFI................. Port Fuel Injection RL SHED ...... Running Loss Sealed Housi ng for Evaporative Determination RVP............... Reid Vapor Pressure SHED ............ Sealed Housing for Evaporative Determination VT SHED...... Variable Temperature Sealed Housing for Evaporative Determinationiii Table of Contents

Background ..................................................................................................................... . 1
Discussion ..................................................................................................................... ... 2 Project Timing......................................................................................................... 3
Vehicle Selection and Procurement ........................................................................ 3
Fuels and Test Parameters....................................................................................... 4
Pre-Test Stabilization on the Test Fuel ................................................................... 4 The Test Concept .................................................................................................... 5
Permeation .............................................................................................................. 5 Tank Vapor Venting.......................................................................................... 5
Leaks ....................................................................................................................... 6 A Test Method for Separating Permeation from Tank Venting and Leaks ............ 6 Examples of Measurements .................................................................................... 9
Static Permeation and Leak Test.................................................................... 9 Dynamic (Running Loss) and Hot Soak Test .............................................. 11 The Running Loss Driving Cycle ................................................................ 13 Diurnal Testing......... ................................................................................ 15
The Issue of Non-Fuel Emissions .................................................................................. 23
An Overview of What Was Learned.............................................................................. 27 Acknowledgements........................................................................................................ 28 Appendix I..................................................................................................................... . 29 Appendix II .................................................................................................................... 33iv List of Figures

Figure Description Page 1 Control System Schematic ....................................................................... 5 2 Sealed Housing for Evaporative Determination ...................................... 6 3 Trap Canister............................................................................................ 6
4 Static Test - Pressurization....................................................................... 7 5 Static Test – Fuel Pump Energized .......................................................... 8
6 Static Test Results.................................................................................... 9 7 Static Permeation – Implanted Leak ...................................................... 10 8 Running Loss SHED.............................................................................. 12 9 Running Loss Driving Cycle.................................................................. 13 10 Dynamic Test Results ............................................................................ 14 11 Dynamic Test Results – All Ten Vehicles ............................................. 14 12 Three Day Diurnal Permeation .............................................................. 16 13 Temperature and RVP Effects ............................................................... 17 14 Low Temperature Diurnal – 7 psi Fuel.................................................. 18 15 High Temperature Diurnal – 7 psi Fuel ................................................. 18 16 Low Temperature Diurnal – 9 psi Fuel.................................................. 19 17 High Temperature Diurnal – 9 psi Fuel ................................................. 19 18 Canister Breakthrough ........................................................................... 20 19 Canister Breakthrough ........................................................................... 21 20 Hose Configurations .............................................................................. 22
21 Canister Vent Hose – Vehicle Installation............................................. 23
22 Non-Fuel Emissions............................................................................... 24 23 Non-Fuel Component Permeation ......................................................... 24 24 Non-Fuel Effects on High Temperature Diurnal ................................... 25 25 Non-Fuel Effects on Low Temperature Diurnal .................................... 25 26 Non-Fuel Component Permeation ......................................................... 26
27 Blank SHED Test .................................................................................. 29 28 Blank SHED Test Set-up ....................................................................... 30
29 Blank SHED Test Results – SHED 14................................................... 30
30 Blank SHED Test Results – SHED 15................................................... 31 31 Trap Canister Emissions – Blank SHED Test ....................................... 31 32 Repeat of Figu re 12-Three Day Diurnal Permeation... ................... 32

List of Tables

Table Description Page 1 CRC E-77 Pilot Study Test Fleet .............................................................. 3 2 CRC E-77 Permeation Pilot Study Tests ................................................. 15 3 Diurnal Vapor Generation........................................................................ 211 

## Vehicle Evaporative Emission Mechanisms: A Pilot Study

BACKGROUND The Coordinating Research Council, Inc. (CRC) has sponsored a variety of timely vehicle evaporative emission test programs over the last two decades, adding greatly to the knowledge
base of mobile-source inve ntory issues. Included in the research were the:

• Auto-Oil Hot Soak Pilot Study (1993) 300 vehicles

• CRC E-9 Real-Time Diurnal Study (1996) 150 vehicles

• CRC E-35 Running Loss Study (1997) 150 vehicles

• CRC E-41 Late Model In-Use Evap Emissions (1998) 50 vehicles

CRC Project E-41 examined the evaporative emissions of fifty 1992 to 1997 model year
vehicles. Six of the vehicles were certified to the federal “Enhanced Evaporative Emission” standards, but were tested at low age and miles. The U. S. enhanced evaporative emissions requirements were phased in nationally, starting with the 1996 model year vehicles, with full implementation by the 2000 model year. These requirements had a major impact on the design and content of the systems used for evapor ative emissions control. CRC Project E-41
concluded that the six newer ve hicles tested performed well ag ainst their respective Enhanced Evaporative emissions certific ation requirements, but suggest ed that a similar study be conducted after this class of vehicles had aged.

In 2004, CRC committee members recommended a fo llow-up study to investigate the in-use performance of the “enhanced evaporative emi ssion” fleet after it had accumulated age and
miles. The committee discussed the best wa y to conduct such a study. Determining the vehicle’s total evaporative emission rates is of interest, but the measurements should also be focused on isolating the parameters useful for modeling. This was not to be a “compliance”

program.
Vehicles are certified by demons trating emission performance at levels below published limits. For vehicle evaporative emissions, there are tests that measure three modes of vehicle operation:

1. Running Losses

2. Hot Soaks

3. Diurnal Emissions

Certification tests, which are performed under specific conditions with tightly controlled parameters, may represent extreme conditions of temperature and duration. The running loss test, for example, consists of a single drive lasting more than one hour, certainly longer than the typical urban trip.

Inventory modelers have used information from the certification tests to help estimate the
contribution of vehicle emissions to the atmo sphere, but more information is needed to determine the emission rates at different temperatur es, different trip lengths, and with different fuels. In 2005, EPA contracted Harold Haskew & Associates, Inc. to suggest a different approach for gathering the data necessary to model evaporative emissions. The resulting report, “A New Approach to Modeling On-Road Vehicl e Evaporative Emissions,” was published June 2, 2005. This new approach suggested measuring the mechanisms of evaporative emissions,
instead of the modes.2 The mechanisms were defined as:

• Leaks

• Diurnal displacement vapors

• Permeation

Diurnal vapors and permeation were thought to be functions of ambient and vehicle temperature and fuel composition. Emissions from leaks are not thought to be a property of the fuel. The challenge was to invent a procedure or test that would allow the separation of leaks from diurnal vapors and leaks from permeation. Characterization of the emission mechanisms
of the fleet could lead to more informed estimates of the evap orative emission rates at various temperatures, with different fu els, and driving conditions.

A separate CRC Project, E-65, “Fuel Permeation from Automotive Systems,” measured and reported the permeation of ten different vehicle fu el systems with three different gasolines. This project vented the tank va por emissions outside the VT-SHED to allow an independent measurement of permeation. That experience sugg ested that it should be possible to measure both permeation and the tank venting loss during a real-time (24 hour) diurnal event, if a separate trap canister was placed outside th e VT-SHED and the vehicle’s canister loss
collected.

CRC Project E-77 evolved as a pilot study to de termine if the mechanisms of evaporative emissions could be measured effectively. If the pilot study were a success, a follow-on program could continue to develop addi tional data, suitable for input to current and proposed inventory models, which could assist in modeling current and future mobile-source emissions. This work is timely as this category of newer vehicles w ill become the predominant class of vehicles in the light-duty fleet.

This report focuses on the process of measuri ng emission mechanisms and the lessons learned to date. Plots of the test data are presented in this report’s appendix. Th e raw data are available
in MS Excel ® format from the CRC website (www.crcao.org).

DISCUSSION

There were a number of elements involved in this pilot study.

• Project timing

• Vehicle selection and procurement

• Fuels and test parameters

• Pre-test stabilization on the test fuel

• The test concept: measuring leaks, permeation, and diurnal vapor losses

• Examples of measurements

• Non-fuel emissions

• Overview of what was learned3 Project Timing - The first draft proposal was consid ered by CRC in May 2004, emphasizing the need for follow-up to Project E-41 given the accumulation of time and miles by enhanced evaporative control vehicles. A request for proposals was issued in October 2005. HH&A’s proposal was based on the use of new concepts to measure the “mechan isms” of evaporative emissions, rather than conventi onal “certification-type” tests. HH&A was awarded the contract in February 2006 for a “Pilot Study of Ten Vehicles ” to investigate this new concept. Data collecting began in early July 2006 and ended in early 2007.

Vehicle Selection and Procurement - Nine vehicles were recruite d from the Phoenix area. One vehicle (Vehicle 6, a 1996 Chevrolet Cavalier) was tested twice. It was tested the second time with an implanted leak in the fuel cap to represent a “leaker” (renumbered Vehicle 7). The sample was not intended to represent the enti re in-use fleet, but rather a small sample distributed between makes, models, and technologies.

The test vehicles came from a population that was comprised almost entirely of port fuel injection models with in-tank fuel pumps. The test procedures would have to be modified if older, carbureted, or advanced de sign new vehicles were included.

The following mix, certified for sale in all fifty st ates (i.e., meeting both federal and California evaporative emission standards) was chosen:

• Three 1990-1995 MY vehicles certifie d to Pre-Enhanced standards

• Five 1996-2000 MY vehicles certif ied to Enhanced standards

• One 2007 MY vehicle certified to the new Tier II standards

Table 1 - CRC E-77 Pilot Study Test Fleet

Vehicle
Number Model
Year Make Model Eng.
Size
L. Fuel System Odo.
Miles Tank
Size
Gallons Fuel Tank
Material Pre-Enhanced Evap 3 1992 Honda Accord 2.2 PFI 71,129 17.0 Metal 10 1992 Toyota Camry 2.2 PFI 162,838 18.5 Metal 9 1995 Plymouth Neon 2.0 PFI 106,220 11.2 Metal Enhanced Evap 1 1996 Chevrolet S-10 4.3 PFI 68,420 19.0 Metal 6 1996 Chevrolet Cavalier 2.2 PFI 112,768 15.3 Metal 7 1996 Chevrolet Cavalier (w/leak) 2.2 PFI 113,125 15.3 Metal 8 1996 Ford Explorer 4.0 PFI 114,822 21.0 Metal 4 1999 Dodge Grand Caravan SE 3.3 PFI 98,765 20.0 Plastic 2 2000 Toyota Tacoma 3.4 PFI 80,557 15.1 Metal Tier II (near zero) 5 2007 Ford Taurus 3.0 PFI 6,916 18.0 Metal4 Candidate owners were offered incentives to pa rticipate in the program. The incentives were the use of a loner car (a pre-paid rental vehicle) and free fuel during the vehicle preconditioning and the vehicle test period. The test plan required having the owner drive the selected (and committed) vehicle for a minimum of four weeks on ethanol-free road fuel before the vehicle was submitted for testing. Vehicle owners signed an agreement to use only fuel provided by the laboratory for th e four-week minimum period prio r to testing. Unlimited fuel fills were permitted during normal working hours. During non-working hours and weekends, owners were permitted to contact laboratory personnel to obtain any needed additional fuel. Fuel usage for each vehicle fill was logged and compared to accumulated odometer readings to validate that the fuel usage and mileage accumula tion were in order. No discrepancies were noted during the pilot study.

Initial screening included a revi ew of the emission sticker to determine the certification category and documentation of the make, model y ear, engine family, evaporative family, and accumulated odometer reading. The owner was as ked if the vehicle had undergone collision repairs or had recently been repainted. New tires and paint emit at an unrepresentative rate, and were excluded from the program. The tires on each vehicle were visually inspected, and the purchase date of obviously new tires was determin ed. The engine compartment was inspected. Signs of collision repair and/ or engine modifications were noted. Tampering, extreme odometer readings, and/or unusual equipm ent configurations were excl uded. A final inspection looked for any unusual hydrocarbon odors or signs of spills . All exceptions were resolved prior to acceptance of a particular candidate.

Testability issues were also noted during this initial inspection. Ti re conditions, cooling systems, brakes, and exhaust systems were inspected to insure the vehicle could be successfully
tested. All vehicles had accumulated at leas t 4,000 miles (a project requirement) prior to entering the test program. A TL’s Project Manager reviewed each specific recommended candidate with the HH&A Program Direct or prior to final acceptance.

Fuels and Test Parameters - The statement of work specified that the pilot study focus on a non-oxygenated (E0) fuel at two vol atility levels, 7 and 9 psi RVP. CRC supplied the fuel for the project at 7 psi volatility. The laboratory added butane to the base fuel for the 9 psi
evaluation.

The test temperature for the static and dynami c tests was 86oF. This is approximately the average temperature of the Federal (72o to 96oF) and California (65o to 105oF) diurnal certification tests, and a typical temperature for a summer day.

The diurnal test temperature range was specified at two levels, 65o to 105oF (the California certification specification), and a higher temperature range, 85o to 120oF (representing a severe temperature day).5 Pre-Test Stabilization on the Test Fuel - Many areas of the United States were required to use an oxygenated fuel to improve vehicle em issions, especially during the summer season. While MTBE was the most common oxygenate , ethanol was also used. Project E-65 demonstrated that the permeation of vehicle fu el systems increased w ith the use of fuels containing ethanol, compared to fuels with MTBE, or no oxygenate. Project E-65 also demonstrated that if ethanol had been used, it could take two to four weeks for the ethanol increase to dissipate. With that in mind, the de sign of the pilot program required that vehicles be operated for four or more weeks with a know n oxygenate-free fuel befo re starting the test

sequence.

The Test Concept: Measuring Leaks, Permeation and Diurnal Vapor Losses - This pilot study evaluated the use of a new methodology for understanding and quantifying vehicle evaporative emission rates. This new concept pa rtitions 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 in a vehicle fuel system 1

. 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 al so strongly affected by gasoline composition, especially w ith ethanol-containing fuels.

Tank vapor venting emissions are controlled by fitting a carbon canister to the atmospheric tank vent. Figure 1 is a schematic of a typical earl y control system. During a daily heating period, the temperature of the vehicle’s fuel tank in creases, forcing HC vapors from the tank. Excess emissions, exceeding the carbon canister’s cap acity, are vented to the atmosphere.

Figure 1 - Control System Schematic

1 “Fuel Permeation from Automotive Systems: Final Report CRC Project E-65,” Haskew, Libert y and McClement, September 2004, avail able

on the CRC and California Air Resources Board websites.6 Leaks can be liquid or vapor. Mass emissions are measured in a VT SHED. The SHED test
method combines all three emission mechanisms (leaks, diurnal venting, and permeation) into a single
test result.

The SHED technique 2

, 3 involves placing the vehicle in a sealed enclosure (Fi gure 2), and calculating the mass in the enclosure from the volume, density and
concentration in the enclosur e 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. Figure 2 - S ealed H ousing for

E vaporative D etermination

The goals of this pilot study were to determin e if the three evaporative emission mechanisms could be separated and individua lly quantified, as well as to pr ovide an indication of how the “enhanced evaporative emission” vehicl es were performing as they aged.

Permeation and tank venting losses are strongly driven by fuel composition, ambient temperature, and ambient temperature change. Li quid leaks are not strongly affected by normal summer temperatures, and are though t to have two components:

1. Static leaks occurring while th e 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 Permeati on from Tank Ve nting and Leaks - Previous CRC Project E-65 had separated the canister loss fr om 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 scal e outside the SHED, as shown in Figure 3. 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 ther e was no vapor created at constant temperature. Th is vent was closed to pressurize the system for the leak evaluations. The resulting SHED increase in HC mass was

2 SAE 891121 “Evaporative Emissions Under Real-Time Conditions.”

3 SAE 901110 “The Development of a Real-Time Evaporative Emission Test.” Fi g ure 3 - Tra p Caniste r7 permeation 4 . The last mechanism that needed to be evaluated was leaks. Leaks can be both vapor and liquid. A liquid leak can have signif icant 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 me thodology, without success. The techniques used in this project required the us e of a SHED for measurements. The techniques were not simple, but they proved effective.

Leaks from the vehicles chosen for this pilot study 5 were quantified in a th ree-step test process. The first step was to measure the permeation ra te of the vehicle at 86oF. The vehicle was
allowed to stabilize at 86oF in the SHED and the permeation rate was measured. The experience gained was that a vehicle’s permeation rate lies in the 20 to 90 mg/hour range. The presence of a static liquid leak is thought to overwhelm this valu e; such a leak would (or could) be apparent by inspection. The s econd part of the test, looking for pressure driven leaks in the vapor system, was performed by pressu rizing the vehicle’s tank to 5” H 2 O through the fuel cap and tubing from outside the SHED (Figure 4) . The special fuel cap, the hose and the pressurization apparatus was insta lled before the start of the se quence. The HC concentration in the SHED was monitored, and the increase in the mass of HC in the SHED was compared to the static permeation rate. If th ere was no (or insignificant) rate of increase, it was deduced that no vapor leak is present.

4 This is a simplification. There are other HC sources pr esent 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.

5 The early and enhanced evaporative emission control vehi cles tested had port fuel injected (PFI) engines with in-tank fuel pumps and carbon control of venting emissions. Figure 4 - Static Test – Tank Pressurization8 A final test was to energize the vehicle’s fu el pump and pressurize the system up to and including the injectors (Fi gure 5). If there were a pressure leak in the liquid system, an increase
in the SHED mass over time would be seen, i.e., the leak would be additive to the permeation rate. Example of this test methodology follows.

Figure 5 - Static Test – Fuel Pump Energized9 Examples of Measurements – There were three basic te sts used in this study;

1. Static Permeation and Leak Test

2. Running Loss and Hot Soak Test

3. Diurnal Tests

Static 86 F Permeation

Vehicle 1 - 7 PSI

240 242 244 246 248 250 252 254 256 258 260 262

0 20 40 60 80 100 120

Test Time - minutesSHED Mass - mg Basic Permeation Rate at 86 8.6 mg/hr (206 mg/day) Incremental Incr. w/ pressurized tank 3.0 mg/hr Incremental Incr. w/ Fuel Pump 'On' 0.0 mg/hr

Steady State

Permeation Pressurize

the Tank
Power the Fuel Pump

Test 6875

Figure 6 – Static Test

The Static Permeation and Leak Test Figure 6 illustrates the test results from one of the pilot tests (Vehicle 1 – 1996 Cavalier on 7 psi fuel). Th e horizontal axis is the test time in minutes,
and the vertical axis is the calculated HC mass in the SHED in milligrams . The SHED analysis system included a Rosemont FID calibra ted on propane, but e xpressed as ppm C1.

The first 60 minutes of the test were devoted to the static permeation measurement. The vehicle was placed 6 in the constant temperature (86°F), a llowed to stabilize for an appropriate amount of time, and then the test began. At time zero in Figure 6, the SHED mass estimate was 242 milligrams. The HC concentration in the SH ED was recorded every 30 seconds, and the mass for that time calculated, using the hot so ak SHED calculation me thod defined in 40 CFR § 86.138-90. The red dots indicate the mass estim ate for each of the first 30 minutes of
measurements. These data were retained but not used in the permeation rate measurement.
The next 30 minutes of measurement were made in the same fashion, and the time/mass values
entered in an Excel ® file where the “SLOPE” value was returned and became the “static

6 The vehicle was set up to run two types of leak tests during this test period, the “system pressurization,” and the “fuel pump energized.” Both require that the canister (tank) vent be sealed. The procedure used to do this is block off the canister’s vent path at the external bulk-head fittin g at the SHED wall at the start of the pressurization, and throughout the remainder of the test.10 permeation rate” for that vehicle a nd fuel (expressed as an hourly ra te). In this example, the rate is 8.6 mg/hour.

At the 60 minute point, the tank was pressurized using the apparatus shown in Figure 4 to 5”

H 2 O. This pressure was actively maintained for the next 60 minutes during the “system pressure test” and the “fuel pump en ergized” parts of the leak tests 7 . The mass results from the constant pressure portion of the test from 75 to 90 minutes were used to validate a negative, i.e., to document that there was no vapor system leak in the test vehicle. If the time rate of
emissions measured in the SHED was the same as the previously measured “permeation rate,” there was no vapor leak of consequence present in the vehicle at that time.

During the time period from 90 to 120 minutes (the last 30 minutes of the test period), the vehicle’s in-tank fuel pump was externally ener gized to create pressure in the vehicle’s liquid fuel system, up to and incl uding the fuel injectors.

Static Permeation Test Results with a Leak Present - One of the vehicles was evaluated with an implanted leak to see if the test procedures coul d identify and quantify the impact of a leak.

The vehicle chosen for this evaluation was Vehicle 6, the 1996 Chevrolet Cavalier. We replaced the vehicle’s fuel cap with a similar cap with a 0.02” di ameter hole in it. This is a common test cap tool used for on-board diagnosti cs development. The vehicle was renamed as
Vehicle 7. The static test resu lts are shown in Figure 7 above.

7 The “actively maintained” comment means that the test operator had to watch and adjust the supply during this time period to hold it at the desired level. Figure 7 - Static Permeation- Implanted Leak Static 86 F Permeation
Vehicle 7 (with implanted leak) - 7 PSI

0 200 400 600 800 1000 1200 1400 1600

0 20 40 60 80 100 120

Test Time - minutesSHED Mass - mg Basic Permeation Rate at 86 59.0 mg/hr (1416 mg/day) Incremental Incr. w/ Fuel Pump 'On' 2417.3 mg/hr

Steady State

Permeation Power the Fuel Pump

Test 6963

Vehicle 0611 The static permeation rate for Vehicle 6 wa s 26 mg/hour. With the implanted leak, the measured value increased to 59 mg/hour. Therefor e, the leak added an estimated 33 mg/hour to the vehicle emission rate, or more than double the original value.

The step where the vehicle vapor system is pressurized to 5” H 2 O was not performed with the implanted leak. Forty-five minut es of SHED measurement were used to calculate the static performance rate, rather than the 15 minutes used on the other vehicle tests. The plot of the
measurements indicated that the increase in SHED mass was constant for this period.

The effect of energizing the fuel pump to pre ssurize the fuel liquid system gave a dramatic increase in the SHED measurement during this period. The incr ease of 2.3 g/hour was attributed to the agitation and heating occurring in the fuel ta nk as energy was supplied to the pump (thought to be in the range of 60 to100 watts) and the return fuel sprayed into the fuel

vapor space.

This demonstration confirmed that the pilot test procedure concept could identify vapor leaks.

Dynamic (Running Loss) and Hot Soak Test - The preceding section addressed the concepts of separating the permeation emission rate from th e tank venting emission rate, and establishing the presence or absence of leaks. The second part of the pilot study included a dynamic test to measure the permeation and tank venting emissi on rate during vehicle operation (“running losses”) and the temporary condition following ve hicle operation known as the “hot soak.”

The “dynamic” part of the dynamic test comes from the fact that the vehicle is driven and the system temperatures rise duri ng the test. The ambient temper ature in the Running Loss SHED was held constant at 86°F, while the vehicle’s fuel system te mperature rose during the test. Two 1435 second (23.9-minute) LA-92 driving cycl es were performed during the running loss measurements, consecutively, with no soak betw een. During this period fuel temperature was expected to rise on average approximately 18°F above the initial ambient temperature. The running loss air handling system includes a propor tional speed under-car blower that is slaved to dynamometer speed. This apparatus was used during running loss tes ting with minor tuning for specific vehicles. It is, without additio nal input, capable of reasonable fuel tank temperature control. Each vehicle was fitted wi th a “skin” thermocouple at the front of the tank, at approximately the 1/8 th fill level to represent the fuel liquid temperature. No attempt was made to follow a predefined fuel tank temp erature profile (FTTP) in this program. Fuel temperatures were recorded, and results ar e available in the real-time records.

Vehicle running loss emissions are measured in a special version of a “SHED” known as the “Running Loss SHED,” (RL-SHED) (Figure 8), which includes a chassis dynamometer for simulating the vehicle driving load s. The vehicle is operated insi de this sealed enclosure over some chosen driving cycle. The increase in HC emissions inside the enclosure are measured and calculated as mass emissions (40 CFR §86.163-96). The execution is complicated by several factors, including:

1. The engine must be supplied with external induction air. 2. The exhaust must be conducted externally without any leaks. 3. The load supplied to the vehicle through the chassis dynamometer must not create or
allow external leaks.12 4. The internal SHED temperature must be ma intained while sizable heat is rejected to the ambient by the running engine and exhaust. 5. The cooling air supplied to the radiator must be modulated to represent the vehicle’s road speed. 6. The underbody (and especially the fuel syst em) temperature should represent the rate of rise experienced by a real road-drive.

Canister vent losses were isolated from the pe rmeation emissions using the same technique, by venting the carbon canister’s fresh air vent to the outside of th e RL-SHED with a leak-tight
Teflon ® hose, where it was connected to a smal l carbon “trap” canister, on a top-loading precision scale. The scale was capable of m easuring changes of 0.01 grams (10 milligrams). There were no tank venting emissions measured on any of the running loss test measurements. All of the vehicles appeared to be actively “p urging” the vehicle’s c ontrol canister during the tests, and drawing fresh air in during the test. If there were any emissions from the vehicle’s canister, as might have occurred if there were no vehicle purge, or if very high volatility fuels with excessive vapor generation were used, it would have been measured. Figure 8 - R unning L oss SHED13 The Running Loss Driving Cycle consisted of tw o cycles of the “Unified Driving Cycle,”
otherwise known as the LA- 92. A velocity versus time plot is shown in Figure 9.

The cycle takes 24 minutes to complete, and cove rs 9.8 miles, with many speed changes. Two back-to-back cycles were driven, the first a “cold start,” the second immediately following the
cold start. The “cold start” condition is usua lly created by soaking the vehicle for a 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 h our before the initial start and run.

The SHED emissions were measured during th e 48+ minutes of engine operation, and then continuously for one hour after the engine was tu rned off. This one hour is the “hot soak” period. The total test time is 1 hour and 48 minutes.

Figure 10 on the next page shows the test results from the 7 psi fuel test on Vehicle 4. The horizontal axis is test time in minutes, and the ve rtical axis is the HC mass measured in the RLSHED during the test period. Th e SHED mass emissions for the first 48 minutes of the test are shown with the green line in the plot. Th e regression analysis capability in Excel ® was used to
calculate a second order curve to the 96 data points in th e 30-second measurements during the 48 minute drive. That relationship is shown w ith the black smooth trace through the green line.

The engine was shut off at the end of the drive, and the analysis system continued to measure the HC emissions in the SHED. This repres ents the “hot soak” portion of the test.

A comparison plot of the ten vehicle test s are shown in Figure 11 on the next page. Figure 9 - RL Driving Cycle Unified Cycle (LA-92)

0 10 20 30 40 50 60 70 80

0 5 10 15 20 25
Test Time - minutesSpeed - 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) 9.8214 Running Loss and Hot Soak

E77 Vehicles

0 500 1000 1500 2000

0 20 40 60 80 100

Test Time - minutesCumulative Permeation - mg Running Loss Hot Soak

Vehicle 1 = 0.017 g/mi Vehicle 2 = 0.025 g/mi Vehicle 3 = 0.039 g/mi Vehicle 4 = 0.009 g/mi Vehicle 5 = 0.002 g/mi Vehicle 6 = 0.011 g/mi Vehicle 7 = 0.012 g/mi Vehicle 8 = 0.009 g/mi Vehicle 9 = 0.011 g/mi Vehicle 10 = 0.069 g/mi Figure 10 – Dynamic Test Results Running Loss and Hot Soak

Vehicle 4 - 7.0 Psi

y = -0.0398x 2 + 5.5741x

R 2 = 0.9865 y = -0.0087x 2 + 2.3904x + 104.51

R 2 = 0.9004

0 50 100 150 200 250 300

0 20 40 60 80 100 120

Test Time - minutesCumulative Permeation - mg

Test 25636 Running Loss Hot Soak

Running Loss Std. =0.05 g/mi This Test = 0.009 g/mi

Figure 11 – Dynamic Test Re sults – All Ten Vehicles15 Diurnal Testing - The third major element of the pilo t program was diurnal testing using the
external vent for the vehicle’s carbon canister to separate the tank vent ing emissions from the permeation.

Table 2 - CRC E-77 Permeat ion Pilot Study Tests

Diurnal Tests

Static Perm
& Leak
Tests Running
Loss & Hot Soak 7 psi
65-105°F 7 psi
85-120°F 9 psi
65-105°F 9 psi
85-120°F

Pre Enhanced

Veh 3 Honda Accord 6902 25635 3 day

6915 3 day

6925 Veh 9 Plymouth
Neon 6969/6975 25646 6973 6974

Veh 10 Toyota Camry 6977 25648 6983

Enhanced

Veh 1 S-10 PU 6875 25632 6857 6865 6888 6893
Veh 2 Tacoma PU 6890 25634 6883. 6904 6896 6899 6929 Veh 4 Dodge Caravan 6912 25636 3 day

6919 3 day

6922 3 day

6926 3 day

6927 Veh 6 Chevy
Cavalier 6939 25640 6953 6955 6959 6961

Veh 7 Cavalier
w/leak 6963 25642 6964 6966

Veh 8 Ford Explorer 6949 25641 6954 6956 6957 6962

LEV II

Veh 5 Taurus Sedan 6923 25638 3 day

6928/6931 3 day

6933

Table 2 shows a summary of the tests performed. The vehicles, classified by the emissions standards to which they are certif ied, are shown on the left side of the table. The numbers in the various boxes identify the labor atory’s test ID numbers for th e individual tests. In some cases, two numbers indicate that re peat tests were conducted. Th e purpose of this table is to
indicate the mixture of one and three-day diurnals that were performed, and to indicate the vehicles tested on the 9 ps i (higher volatility) fuel.

Immediately following completion of the hot soak test, the vehicle was moved to a VT-SHED for diurnal testing. The diurnal SHED was used to soak the vehicle at 65°F overnight. The
vehicle soaked a minimum of 16 hours before th e diurnal test was init iated. Again using Project E-65 procedures, the vapor space at the fu el cap and the canister outlet were plumbed to
the outside of the SHED enclosure. A thir d well-purged collector ca nister was used to continuously monitor canister outlet emissions.

The California 65°F–105°F–65°F diurnal temperature profile was used for the baseline test on all vehicles, normally terminating after one 24- hour cycle. One of each vehicle group16 continued for a total of three 24-hour cycles. Continuous measurements of HC levels, ambient conditions, tank weights, and tank te mperature were recorded throughout.

At the end of the baseline diurnal, the SHED was purged and the internal ambient temperature
was raised to 85°F. The vehicle remained in the enclosure for a minimum of 16 hours. The enclosure was purged again, the te mperature was allowed to stabi lize, and a second diurnal was performed. The second diurnal followed an extrem e 85°–120°F cycle. This new cycle rose in proportion to the California 65°–105°F cycle in the first 9 hours, and then dropped back to 85°F over the remaining 16 hours. This is a 35° F temperature change as opposed to the 40°F temperature change in the 65°-105° cycle.

The three vehicles selected for 72-hour tests in the baseline test al so received a 72-hour
extreme diurnal test. All five vehicles certified to enhanced evaporative standards were also tested with 9.0 psi RVP fuel.

Figure 12 shows an example of th e diurnal results obtained during the pilot study for Vehicle 4.
The horizontal axis is the time in hours (72 hours for the 3-day test), and the vertical scale is the HC mass in the SHED for the test period. The high temperature diurnal (85°-120°-85°F) gave about twice the diurnal permeation rate on Vehicle 4, the 1999 Dodge Caravan. The continuous measurement of the tank venting emi ssions on the trap canis ter outside the SHED reported zero change for the test period. Figure 12 – 3 Day Diurnal Permeation Cumulative Permeation

Vehicle 4

0 500 1000 1500 2000 2500 3000 3500

0 10 20 30 40 50 60 70

Test Time - hoursCumulative Permeation - mg. Low Temp - 7 Psi

High Temp - 7 Psi The decrease in SHED mass
shown here is discussed later in the Appendix.17 Another example of the permeation data, again fr om Vehicle 4, is offered in Figure 13. This chart shows both the diurnal temperature and the RVP effect. The lower pair of traces (green and blue) offers a comparison of the RVP eff ect at the lower diurnal temperature test conditions. The upper pair (red and black) compares th e volatility effect at the higher test temperature. At both temperatures, the tests with the higher volatility fuel indicated higher permeation levels.

Comparison plots for the diurnal results for the pilot study are summa rized in Figures 14-17, arranged by emission cont rol system technology. Figure 13 – Temperature and RVP Effects Cumulative Permeation

Vehicle 4

0 500 1000 1500 2000 2500 3000 3500 4000 4500

0 10 20 30 40 50 60 70

Test Time - hoursCumulative Permeation - mg. Low Temp - 7 Psi
High Temp - 7 Psi Low Temp - 9 Psi
High Temp - 9 Psi18 Diurnal Permeation Rates by Technology Group Low Temp. 7.0 psi : E77 Project Vehicles

746.8

546.7

325.4

262.0 503.7

375.6

133.1
105.0

0 100 200 300 400 500 600 700 800

3 9 10 1 2 4 6 7 8 5Diurnal Permeation - mg/day

Pre-Enhanced Enhanced Near

Zero 20704

Vehicle 06 with Implanted Leak

Figure 14 – Low Temperature Diurnal 7 psi Fuel

Diurnal Permeation Rates by Technology Group Hi Temp. 7.0 psi : E77 Project Vehicles

1918.3

953.5 1689.3

530.3 471.5 1070.9

372.0

235.4 196.9

0 500 1000 1500 2000

3 9 10 1 2 4 6 7 8 5Diurnal Permeation - mg/day

Pre-Enhanced Enhanced Near

Zero 27384

Vehicle 06 with Implanted Leak

Figure 15 – High Temperature Diurnal 7 psi Fuel19 Diurnal Permeation Rates by Technology Group Low Temp. 9.0 psi : E77 Project Vehicles

571.1

214.4 695.9

468.5

150.4

0 100 200 300 400 500 600 700 800

12468Diurnal Permeation - mg/day

Enhanced

Figure 16 – Low Temperature Diurnal 9 psi Fuel

Diurnal Permeation Rates by Technology Group Hi Temp. 9.0 psi : E77 Project Vehicles

1048.8

387.4 1396.4

685.4

254.6

0 200 400 600 800 1000 1200 1400 1600

12468Diurnal Permeation - mg/day

Enhanced

Figure 17 – High Temperature Diurnal 9 psi Fuel20 An example of the canister breakthrough perf ormance on Vehicle 4 is shown in Figure 18. These data are from the 3-day test at the lowe r diurnal temperatures with the 9 psi RVP fuel.
The horizontal axis of th e plot is the test time in hours for th e 3 days. The left vertical axis shows the temperatures scale in degrees F. The green trace represents the VT-SHED ambient temperature as it is varied from 65° to 105°F, and the red trace is the fuel temperature as measured with the fuel tank skin thermocouple dur ing the test. The blue trace is the change in the weight of the trap canister (shown on the right vertical scale in grams) used to capture the
vehicle’s canister vent loss.

No canister breakthrough was measured on the first day. On the second day at about the peak ambient temperature, the scale indicated about a gram of break through. On the third day, more canister breakthrough was indicate d, as the trap canister weig ht rose to a maximum of 17

grams.

The decrease in the trap caniste r weight that occurred during the last few hours of the test was the result of the “back-purging” of the system as the fuel tank temperature decreased. During this cooling period, the equilibrium partial pr essure of the HC in the tank vapor space decreased, and air was drawn back into the tank to maintain the system pressure. This flow of
air back into the vehicle’s fuel system purged the trap canister. Figure 18 – Canister Breakthrough Canister Breakthrough and Temperature

Vehicle 4 - 9.0 PSI

60 65 70 75 80 85 90 95 100 105 110

0 10 20 30 40 50 60 70

Test Time - hrsTemperature - deg F

0 2 4 6 8 10 12 14 16 18Canister Breakthrough - grams SHED Ambient
Fuel Temp
Breakthrough

Test 692621 Table 3 Diurnal Vapor Generation (grams) for a 19 gallon tank at 40% fill

Fuel Tank Temperature Change
65°-103°F 85°-118°F

7 psi Fuel 29.5 55.7

9 psi Fuel 56.2 125.0

The GM Reddy model was used to estimate the va por generation for a 19 gallon tank for the
four diurnal test combinations that were included in the pilot study. These results are shown in
Table 3. These calculations i ndicate that the vapor genera tion roughly doubles for both the increase in test temperature and the increase from 7 to 9 psi in fuel volatility. The high temperature and the higher volatility fuels crea te a fourfold increase in vapor generation.

Another example of the canister breakthrough meas urement is shown in Figure 19, from a test on Vehicle 1. The combination of high RVP a nd high temperature produced the first evidence of canister breakthrough, as shown with the green trace in the plot above. More interestingly, this plot shows that the permeation rate (red trace) increased significantly as the vehicle’s canister started to break-through into the extern al trap canister. This pointed out that the connection for the canister loss plumbing has to be made at the canister, rather than at the
external vent solenoid. This is ex plained further in the following section. Cert Target

Figure 19 - Canister Breakthrough Canister Breakthrough and Temperature

Vehicle 1 - 9.0 PSI

80 85 90 95 100 105 110 115 120 125

0 5 10 15 20 25

Test Time - hrsTemperature - deg F

-5 5 15 25 35 45 55 65 75 85 95Incremental Permeation - mg/2Canister Breakthrough - grams SHED Ambient

Incr. Permeation

Breakthrough

Test 6893 Peak Canister Breakthrough was 70.5 gms at 13 hrs.22 The Original Hose Configurations on the Test Vehicles

1. The fuel feed hose from the tank to th e engine - contains liquid fuel

2. The vapor hose from the tank to the canister - contains fuel vapor – during diurnal heating conditions, it carries head space vapor from the tank to the canister - during diurnal cooling conditions, it has purge vapors from the carbon bed at something less than the head space vapor concentration.

3. The purge hose from the canister to the e ngine – during engine operation and at the start of the purge, it may have high concen tration HC vapors, but for a majority of the purge, it contains mainly air, with low level HC concentration.

4. The vent hose from the carbon canister to th e vent solenoid/fresh air inlet filter for
the canister. On rare occasions when the canister is ove rloaded and breaking through, it contains high level HC vapors. Otherwise, it contains only air. This hose is not required to be a low permea tion material, and may be simply NBR.
5. The laboratory’s affixed connection hose to route the canister breakthrough vapors to the SHED external trap caniste r for collection and quantification.

The hose that was to be circumvented is the ve nt hose identified as #4 in Figure 20. Another illustration is shown in Figure 21. 1

2 3

4

5

Figure 20– Hose Configurations23 Procedures were revised to make the test connection directly at th e canister, rather than at the original site, the remote vent. The Teflon ® hose material used to rout e the canister vent loss to the outside of the SHED (iden tified as # 5 in a previous figure) was verified to be low permeation material. A discussion of this investigation is offered in the Appendix.

THE ISSUE OF NON- FUEL EMISSIONS

One major goal of this pilot study was to quantify the fuel emissions from vehicles under the
chosen test conditions. N on-fuel (background) emissions 8 are known to be present in the ambient samples measured. These background emissions were to be minimized or identified in this study. Vehicle selection elimin ated candidates with recent pa int repairs or newly replaced tires, or any vehicles with identifiable HC odors or spills detectable with a sniffer in the trunk or interior. The remaining paint and vinyl cont ributions are confounded into the vehicle level

measurements.

Other non-fuel emissions can originate from wa sher solvent (methanol) and refrigerant (R-12, R-134a). The laboratory purchased and experimented with an INNOVA 9 analyzer to identify methanol and refrigerants present in the measur ements on a routine basis towards the end of the pilot program.

8 See SAE 912373, “Real-Time Non-Fuel B ackground Emissions,” H. Haskew, et al.

9 Model 1412 Photoacoustic Multigas Analyzer from California Analytical Instruments, Inc. Hose 4 – Possibly a high permeation

material Figure 21 – Canister Vent Ho se – Vehicle Installation24 The discussion that follows concerns the issues with Vehicle 8, and how they were resolved once the anomaly was identified as a large refrig erant leak. The diurnal permeation plot for Vehicle 8 (Figure 22) showed an atypical increase in the perm eation during the last four hours
of the test. The INNOVA allowed continual meas urement of methanol and refrigerant (R134a) in the SHED during the diurnal test. Subtracting those contaminants from the HC (FID) reading provided insight into the s ource of the unusual data.

The Explorer (Vehicle 8) had a refrigerant leak that was identified by the FID as a hydrocarbon, and thought to be gasoline. When the FID reading was corrected, the diurnal mass was reduced from 280 mg/ day to 109, a 61 % reduction. The methanol correction was insignificant. The R134a measurement, shown in the red trace in Figure 23, is calculated as if it were a fuel molecule, using the customary dens ity of fuel vapors (16.83 grams per cubic foot per ppm carbon). The actual mass of refrigeran t is much higher, due to the additional noncarbon and hydrogen atoms contained in the molecule. The methanol measured was very low in this test, and the ethanol identified by the INNOVA was ~ 20 mg, a trace hang-over measurement. The ethanol is included in the corrected SHED mass, since it is fuel. Effect of Non-Fuel Contaminants

Vehicle 8 - 7.0 PSI

0 50 100 150 200 250 300

0 5 10 15 20 25

Test Time - hrsCumulative Permeation - mg Raw SHED Mass

Corrected for R134a

Corrected for Methanol

Corrected SHED Mass Low Temp Diurnal

Test 6954

Figure 22 – Non-Fuel Emissions

Non-Fuel Component Cumulative Permeation
Vehicle 8 - 7 psi

-20

0 20 40 60 80 100 120 140 160 180 200

0 5 10 15 20 25

Test Time - hrs.Cumulative Permeation - mg R134a

Methanol

Ethanol Low Temperature Diurnal

Figure 23 – Non-Fuel Component Permeation25 Figure 24 shows the effect of the non-fuel components on the total high temperature diurnal permeation on Vehicle 8.

The low temperature 7 psi diurnal test on th e Cavalier Vehicle 6 had both refrigerant and methanol present at significant levels. Figur e 25 shows the test results with the red trace indicating the “normal” FID measurement, and the two corrections performed in a step-wise method, first subtracting the R134a misidentified as gasoline (blu e trace), and then subtracting
the methanol to obtain the final corrected diurna l result as shown in the black trace. The
diurnal measurement is corrected fro m 477 to 376 mg day, a 21% reduction. Effect of Non-Fuel Contaminants

Vehicle 8 - 7.0 PSI

0 50 100 150 200 250 300 350

0 5 10 15 20 25

Test Time - hrsCumulative Permeation - mg Raw SHED Mass

Corrected for R134a

Corrected for Methanol

Corrected SHED Mass High Temp Diurnal

Test 6956

Effect of Non-Fuel Contaminants

Vehicle 6 - 7.0 PSI

0 100 200 300 400 500

0 5 10 15 20 25

Test Time - hrsCumulative Permeation - mg Raw SHED Mass

Corrected for R134a

Corrected for Methanol

Corrected SHED Mass Low Temp Diurnal

Test 6953

Figure 25 – Non-Fuel Effects - Low Temperature Diurnal26 The R134a and methanol measurements for this test (6953) are show n in Figure 26 on the following page.

Figure 26 - Non-Fuel Component Permeation Non-Fuel Contaminant Cumulative Permeation

Vehicle 6 - 7.0 PSI

0 10 20 30 40 50 60

0 5 10 15 20 25

Test Time - hrsCumulative Permeation - mg R134a

Methanol Low Temp Diurnal

Test 695327 AN OVERVIEW OF WHAT WAS LEARNED

The Pilot Study accomplished the objectives of th e project and added to the bank of knowledge that helps in understanding the mechanisms and magnitude of vehicle evaporative emissions.
These are summarized as:

• Tank Venting (Canister Losses) can be separated from the permeation. See the plot at Figure 18, “Canister Breakthrough” that illustrates the tank venting, or canister breakthrough, occurring during heating periods on the third day, and then decreasing during the “back-purge” period.

• Permeation rates increase with temperature. See the many plots of permeation rate versus time (“Diurnal Time Resp onse”) in Appendix II organized by vehicle
number.

• Permeation emissions are higher when measured with 9 psi RVP E0 gasoline than with 7 psi E0 gasoline. See figure 13 at page 18. Permeation is not thought to be a function of system pressure, but we found it to increase with higher vapor pressure fuel. The explanation is that th e higher vapor pressure creates higher vapor concentrations in the fuel vapor components (head space, fuel cap seal, vapor handling lines).

• Canister venting connection must be made at the canister. Review the text starting at page 22, a nd Figures 19, 20 and 21.

• High volatility and temperature can create excessive fuel vapors that exceed canister capacity. See examples of the high temp erature tests on 9 psi fuel in Figures 18 and 19.

• Refrigerant and methanol (non-fuel comp onents) can be a significant fraction
of the SHED measurement. See “The Issue of Non-Fuel Emissions” starting at page 25 of this report.28 ACKNOWLEDGEMENTS:

The authors want to thank and acknowledge the staff and steering committee that guided this

program:

David L. Lax API
Ben Hancock CARB Jeff Long CARB
Hector Maldonado CARB Mike Ingham Chevron Jenny Spravsow Chrysler Ken J. Wright ConocoPhillips Brent Bailey CRC
Jane Beck CRC
Chris Tennant CRC
David Brzezinski EPA
Connie Hart EPA
Dominic DiCicco Ford Cynthia Williams Ford
Steve Cadle GM
Jeff Jetter Honda Mani Natarajan Marathon
David N. Patterson Mitsubishi King D. Eng Shell Hannah Murray Toyota29 

# Appendix I

Additional Information

The following discussion is intended to show that the permeation of the te st vent hoses used by ATL are, for these purposes, zero. The basic c ontamination level inhe rent in a SHED is discussed first, followed by a presentation of te st data intended to m easure the permeation of the test vent hose. The trap can ister HC collection is also comp ared to the value predicted by the Reddy model.

Discussion: Any variable temperature
SHED has an inherent contamination level which can be as high as 50 mg per day under the regulations for an enhanced evap certification test. The contamination is thought to be leftover HC from previous experiences that have
condensed on the SHED internal surfaces during the cooling period. One can measure the contamination level by performing a diurnal test with nothing in the SHED, i.e., a “blank SHED.”

Figure 27 shows a recent (9/15/06)
“blank SHED” test result in ATL’s SHED 15, one of the two that are used for the CRC Projects E-77 and E-65
evaluations. An almost identical value was m easured in SHED 14 during the same period. The
HC mass in a blank SHED increases as the SHED is heated, and then decreases slightly during cooling. The mass in the SHED was estimated to be as high as ~13 mg at the peak value, decreasing to ~7 mg at the test end. The cont amination level can be minimized by repeated heating and purging of the SHED , washing the internal surfac es with a non-HC soap, and avoiding tests of vehicles or objec ts with high emission levels. A 5 to 10 mg level is a realistic goal for day-to-day performance.

Vent Hose Evaluation - The laboratory located a 3 gallon steel tank, previously used to hold calibration gases. The single inlet fitting was re placed with a stainless fitting that mated to the
3/8” ID Teflon ® vent hose that was used in the SHED to vent the fuel system to the outside of the enclosure. The vent hose is approximately 6’ long and terminates at either end with a Swagelok compression fitting. The test set-up is s hown in Figure 28. The intent is for the only item that can permeate in the SHED to be the vent hose. The 3 gallon container was filled with 1.5 gallons (50%) of the E77 7 psi test fuel. The trap canister outside the SHED was used to collect any HC vapors that were emitted from th e tank. Several diurnal tests were performed in SHEDs 14 and 15 with this test configuration. SHED 15 Blank Test

0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0

0 5 10 15 20 25 30

Time in HoursSHED Mass in mg

Figure 27 – Blank SHED Test30 The test results for the vent hos e in SHED 14 were lower than the blank SHED results (Figure 29), i.e., no permeation from the hose. Similar re sults were obtained in SHED 15, as shown in Figure 30.

SHED HC vs Test Time

0 5 10 15 20 25

0 6 12 18 24

Test Time - hoursSHED HC - mg Blank

Tank SHED 14 Steel cylinder 50% filled with 7 psi test gasoline Teflon ® vent hose

Figure 29 – Blank SHED Test Results – SHED 14 Figure 28 – Blank SHED Test Set-up31 The two day test results in SHED 15 are shown in the blue traces in Figure 30, as if they were both run as single day results. The blank SHED re sults are shown in the red trace. Again, the
conclusion is the same: there is no significant permeation from the Teflon ® vent hose used in the test program for E-65 and E-77.

The trap canister collected the venting emissi ons from the steel cylinder. The results were repeated very closely from day-to-day, as show n in Figure 31. The measured emissions were ~3.4 grams during the heating cycle from the 1.5 ga llon of vapor space. The back purge of the trap canister as the fuel ta nk cools is apparent. The Reddy mo del predicts 3.205 grams for a 67 to 103°F temperature heating excursion, which co mpares favorably with the measured values. Figure 30 – Blank SHED Test Results – SHED 15

Collector Weight Change vs Test Time

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

0 4 8 12 16 20 24

Test Time - hoursCollector Weight Change - gms Collector - Day 1

Collector - Day 2 SHED 15

Figure 31 – Trap Canister Em issions – Blank SHED Test SHED HC vs Test Time

0 5 10 15 20 25

0 4 8 12 16 20 24

Test Time - hoursSHED HC - mg Blank

Tank - Day 1

Tank - Day 2 SHED 1532 Comment:

The Teflon ® vent hose does not materially contribute to the evaluation, and it appears that the trap canister works.

Mass “Loss” during the Diurnal Cooling Period

Plots of diurnal mass results sometimes indicat e an apparent mass “lo ss” during the cooling period. Figure 12 is repeated below to illustrate this result, most apparent in the third day’s test results with the high temperature te st conditions (red trace). The ve rtical scale is the calculated
mass in the SHED. That the mass is shown to decrease suggests a “leak” or other problem in
the test results.

This condition has been observed in many test pr ograms, and usually is more evident when the
HC concentration in the SHED is high. We believe that this is a result of partial adsorption, or condensation, of the HC vapors on the cool surfaces in the heat exchanger as it tries to drive the SHED ambient temperature dow n during the cooling cycle.

Cumulative Permeation

Vehicle 4

0 500 1000 1500 2000 2500 3000 3500

0 10 20 30 40 50 60 70

Test Time - hoursCumulative Permeation - mg. Low Temp - 7 Psi

High Temp - 7 Psi

Figure 32 - Repeat of Figur e 12-Three Day Diurnal Permeation33 

# Appendix II

Test Data Plots
All Vehicles34 Static 86 F Permeation

Vehicle 1 - 7 PSI

240 242 244 246 248 250 252 254 256 258 260 262

0 20 40 60 80 100 120

Test Time - minutesSHED Mass - mg Basic Permeation Rate at 86 8.6 mg/hr (206 mg/day) Incremental Incr. w/ pressurize d tank 3.0 mg/hr Incremental Incr. w/ Fuel Pump 'O n' 0.0 mg/hr

Steady State

Permeation Pressurize

the Tank
Power the Fuel Pump

Test 6875 1996 Chevrolet S-10 Enhanced SHED SHED

Results Results Caniste r Permeation mg/day mg/day Loss

V eh Fuel Test Type Date Test# mg/hr (Raw) (Corrected) g 01 7.0 Static Perm 07/06/06 6875 8.6

Press. Incr. 3.0

Prs+Fuel Incr. 0.0

mg 7.0 Dynamic RL 07/07/06 25632 331.4
HS 65.0
RL + HS 396.4

7.0 DHB 65-105 06/23/06 6857 325.4 0.0

7.0 DHB 85-120 06/28/06 6865 530.3 0.0

9.0 DHB 65-105 07/18/06 6888 572.1 0.0

9.0 DHB 85-120 07/20/06 6893 1048.8 70.5 

# Vehicle 135 Running Loss and Hot Soak

Vehicle 1 - 7.0 Psi

y = 0.1381x 2 - 0.3967x

R 2 = 0.9216 y = -0.0312x 2 + 4.728x + 236.07

R 2 = 0.1685

0 100 200 300 400 500 600

0 20 40 60 80 100 120

Test Time - minutesCumulative Permeation - mg

Test 25632 Running Loss Hot Soak

Running Loss Std. =0.05 g/mi This Test = 0.017 g/mi

Diurnal Time Response

Vehicle 1 - 7.0 Psi

60 65 70 75 80 85 90 95 100 105 110

0 2 4 6 8 10 12 14 16 18 20 22 24

Test Time - hoursSHED AMbient Temperature - deg F

-5 0 5 10 15 20 25 30 35Permeation - mg/hr SHED Ambient

Hourly Permeation

Test 685736 Dynamic Diurnal

Vehicle 1 - 7.0 Psi

-5 0 5 10 15 20 25 30 35

60 70 80 90 100 110

SHED Ambient temperature - deg FHourly Permeation - mg/hr

Test 6857

Diurnal Time Response

Vehicle 1 - 7.0 Psi

80 85 90 95 100 105 110 115 120 125

0 2 4 6 8 10 12 14 16 18 20 22 24

Test Time - hoursSHED AMbient Temperature - deg F

0 10 20 30 40 50Permeation - mg/hr SHED Ambient

Hourly Permeation

Test 686537 Dynamic Diurnal

Vehicle 1 - 7.0 Psi

0 10 20 30 40 50 60

80 85 90 95 100 105 110 115 120 125

SHED Ambient temperature - deg FHourly Permeation - mg/hr

Test 6865

Diurnal Time Response

Vehicle 1 - 9.0 Psi

60 65 70 75 80 85 90 95 100 105 110

0 2 4 6 8 10 12 14 16 18 20 22 24

Test Time - hoursSHED AMbient Temperature - deg F

0 10 20 30 40 50 60Permeation - mg/hr SHED Ambient

Hourly Permeation

Test 688838 Dynamic Diurnal

Vehicle 1 - 9.0 Psi

0 10 20 30 40 50 60 70

60 70 80 90 100 110

SHED Ambient temperature - deg FHourly Permeation - mg/hr

Test 6888

Diurnal Time Response

Vehicle 1 - 9.0 Psi

80 85 90 95 100 105 110 115 120 125

0 2 4 6 8 10 12 14 16 18 20 22 24

Test Time - hoursSHED AMbient Temperature - deg F

-5 15 35 55 75 95 115 135 155 175Permeation - mg/hr SHED Ambient

Hourly Permeation

Test39 Dynamic Diurnal

Vehicle 1 - 9.0 Psi

-20

0 20 40 60 80 100 120 140 160 180

80 85 90 95 100 105 110 115 120 125

SHED Ambient temperature - deg FHourly Permeation - mg/hr

Test 6893

Canister Breakthrough and Temperature

Vehicle 1 - 9.0 PSI

80 85 90 95 100 105 110 115 120 125

0 5 10 15 20 25

Test Time - hrsTemperature - deg F

-5 5 15 25 35 45 55 65 75 85 95Incremental Permeation - mg/2Canister Breakthrough - grams SHED Ambient

Incr. Permeation

Breakthrough

Test 6893 Peak Canister Breakthrough was 70.5 gms at 13 hrs.40 Cumulative Permeation

Vehicle 1

0 200 400 600 800 1000 1200

0 5 10 15 20 25

Test Time - hoursCumulative Permeation - mg. Low Temp - 7 Psi

High Temp - 7 Psi

Low Temp - 9 Psi

High Temp - 9 Psi41 2000 Toyota Tacoma Enhanced SHED SHED

Results Results Caniste r Permeation mg/day mg/day Loss

V eh Fuel Test Type Date Test# mg/h r (Raw) (Corrected) g

2 7.0 Static Perm 07/19/06 6890 19.1

Press. Incr. 0.0

Prs+Fuel Incr. 0.0

7.0 Dynamic RL 07/19/06 25634 520.2
HS 0.0
RL + HS 520.2

7.0 DHB 65-105 07/13/06 6883 407.2 0.0
7.0 DHB 65-105 08/01/06 6904 262.0 0.0

7.0 DHB 85-120 07/21/06 6896 471.5 0.0

9.0 DHB 65-105 07/25/06 6899 214.4 0.0

9.0 DHB 85-120 09/12/06 6929 387.4 6.3

Static 86 F Permeation

Vehicle 2 - 7 PSI

200 205 210 215 220 225 230 235 240 245

0 20 40 60 80 100 120

Test Time - minutesSHED Mass - mg Basic Permeation Rate at 86 19.1 mg/hr (429 mg/day) Incremental Incr. w/ pressurized tank 0.0 mg/hr

Incremental Incr. w/ Fuel Pum p 'On' 0.0 m g /h r

Steady State

Permeation Pressurize

the Tank Power the Fuel Pump

Test 6890 

# Vehicle 242 Running Loss and Hot Soak

Vehicle 2 - 7.0 Psi

y = -0.1134x 2 + 14.857x

R 2 = 0.8793 y = 0.0189x 2 - 3.6763x + 592.22

R 2 = 0.5375

0 100 200 300 400 500 600

0 20 40 60 80 100 120

Test Time - minutesCumulative Permeation - mg

Test 25634 Running Loss Hot Soak

Running Loss Std. =0.05 g/mi This Test = 0.025 g/mi

Diurnal Time Response

Vehicle 2 - 7.0 Psi

60 65 70 75 80 85 90 95 100 105 110

0 2 4 6 8 10 12 14 16 18 20 22 24

Test Time - hoursSHED AMbient Temperature - deg F

-10 0 10 20 30 40 50Permeation - mg/hr SHED Ambient

Hourly Permeation

Test 688343 Dynamic Diurnal

Vehicle 2 - 7.0 Psi

-10

0 10 20 30 40 50 60

60 70 80 90 100 110

SHED Ambient temperature - deg FHourly Permeation - mg/hr

Test 6883

Diurnal Time Response Vehicle 2 - 7.0 Psi (Repeat)

60 65 70 75 80 85 90 95 100 105 110

0 2 4 6 8 10 12 14 16 18 20 22 24

Test Time - hoursSHED AMbient Temperature - deg F

-15 -10 -5 0 5 10 15 20 25 30 35Permeation - mg/hr SHED Ambient

Hourly Permeation

Test 690444 Diurnal Time Response

Vehicle 2 - 7.0 Psi

80 85 90 95 100 105 110 115 120 125

0 2 4 6 8 10 12 14 16 18 20 22 24

Test Time - hoursSHED AMbient Temperature - deg F

-10 0 10 20 30 40 50Permeation - mg/hr SHED Ambient

Hourly Permeation

Test 6896 Dynamic Diurnal
Vehicle 2 - 7.0 Psi (Repeat)

-20 -10

0 10 20 30 40

60 70 80 90 100 110

SHED Ambient temperature - deg FHourly Permeation - mg/hr

Test 690445 Dynamic Diurnal

Vehicle 2 - 7.0 Psi

-10

0 10 20 30 40 50

80 85 90 95 100 105 110 115 120 125

SHED Ambient temperature - deg FHourly Permeation - mg/hr

Test 6896

Diurnal Time Response

Vehicle 2 - 9.0 Psi

60 65 70 75 80 85 90 95 100 105 110

0 2 4 6 8 10 12 14 16 18 20 22 24

Test Time - hoursSHED AMbient Temperature - deg F

-10 -5 0 5 10 15 20 25 30Permeation - mg/hr SHED Ambient

Hourly Permeation

Test 689946 Dynamic Diurnal

Vehicle 2 - 9.0 Psi

-10

-5 0 5 10 15 20 25 30

60 70 80 90 100 110

SHED Ambient temperature - deg FHourly Permeation - mg/hr

Test 6899

Diurnal Time Response

Vehicle 2 - 9.0 Psi

80 85 90 95 100 105 110 115 120 125

0 2 4 6 8 10 12 14 16 18 20 22 24

Test Time - hoursSHED AMbient Temperature - deg F

0 5 10 15 20 25 30 35 40 45 50Permeation - mg/hr SHED Ambient

Hourly Permeation

Test 692947 Dynamic Diurnal

Vehicle 2 - 9.0 Psi

0 5 10 15 20 25 30 35 40 45 50

80 85 90 95 100 105 110 115 120 125

SHED Ambient temperature - deg FHourly Permeation - mg/hr

Test 6929

Canister Breakthrough and Temperature

Vehicle 2 - 9.0 PSI

80 85 90 95 100 105 110 115 120 125

0 5 10 15 20 25

Test Time - hrsTemperature - deg F

0 1 2 3 4 5 6 7 8 9 10Canister Breakthrough - grams SHED Ambient

Fuel Temp

Breakthrough

Test 692948 Cumulative Permeation

Vehicle 2

0 100 200 300 400 500 600

0 5 10 15 20 25

Test Time - hoursCumulative Permeation - mg. Low Temp - 7 Psi
Low Temp - 7 Psi (Repeat)
High Temp - 7 Psi
Low Temp - 9 Psi
High Temp - 9 Psi49 1992 Honda Accord Pre-enhanced SHED SHED

Results Results Canister Permeation mg/day mg/day Loss

V eh Fuel Test Type Date Test# mg/hr (Raw) (Corrected) g

3 7.0 Static Perm 07/28/06 6902 32.3

Press. Incr. 2.6

Prs+Fuel Incr. 0.0

7.0 Dynamic RL 08/01/06 25635 753.3
HS 13.8
RL + HS 767.0

7.0 72 DHB 65-105 08/11/06 6915 Day 1 746.8 0.1 Day 2 782.5 0.4 Day 3 1304.4 2.4

7.0 72 DHB 85-120 09/01/06 6925 Day 1 1918.3 1.7 Day 2 3760.8 18.7 Day 3 5674.1 20.4

Static 86 F Permeation

Vehicle 3 - 7 PSI

280 290 300 310 320 330 340 350 360

0 20 40 60 80 100 120

Test Time - minutesSHED Mass - mg Basic Permeation Rate at 86 32.3 mg/hr (775 mg/day) Incremental Incr. w/ pressurized tank 2.6 mg/hr Incremental Incr. w/ Fuel Pump 'On' 0.0 m g /h r

Steady State

Permeation Pressurize

the Tank Power the Fuel Pump

Test 6902 

# Vehicle 350 Running Loss and Hot Soak

Vehicle 3 - 7.0 Psi

y = -0.0093x 2 + 16.242x

R 2 = 0.9985 y = -0.0095x 2 + 1.8287x + 679.63

R 2 = 0.7731

0 100 200 300 400 500 600 700 800 900

0 20 40 60 80 100 120

Test Time - minutesCumulative Permeation - mg

Test 25635 Running Loss Hot Soak

Running Loss Std. =0.05 g/mi This Test = 0.039 g/mi

Diurnal Time Response
Vehicle 3 - 7.0 Psi : Repeat

60 65 70 75 80 85 90 95 100 105 110

0 10 20 30 40 50 60 70

Test Time - hoursSHED AMbient Temperature - deg F

-50 0 50 100 150 200Permeation - mg/hr SHED Ambient

Hourly Permeation

Test 691551 Dynamic Diurnal
Vehicle 3 - 7.0 Psi : Repeat

-40 10 60 110 160 210

60 70 80 90 100 110

SHED Ambient temperature - deg FHourly Permeation - mg/hr Day 1
Day 2
Day 3

Test 6915

Diurnal Time Response

Vehicle 3 - 7.0 Psi

80 85 90 95 100 105 110 115 120 125

0 10 20 30 40 50 60 70

Test Time - hoursSHED AMbient Temperature - deg F

-250 250 750 1250 1750 2250Permeation - mg/hr SHED Ambient

Hourly Permeation

Test 692552 Dynamic Diurnal

Vehicle 3 - 7.0 Psi

-500 0 500 1000 1500 2000 2500

80 90 100 110 120

SHED Ambient temperature - deg FHourly Permeation - mg/hr Day 1
Day 2
Day 3

Test 6925

Canister Breakthrough and Temperature

Vehicle 3 - 9.0 PSI

80 85 90 95 100 105 110 115 120 125

0 10 20 30 40 50 60 70

Test Time - hrsTemperature - deg F

-250 250 750 1250 1750 2250Incremental Permeation - mgCanister Breakthrough - 45 x grams SHED Ambient

Incr. Permeation
Breakthrough

Test 6925 Peak Canister Breakthrough was 46 gms @ 11 hrs of day 353 Cumulative Permeation

Vehicle 3

0 2000 4000 6000 8000 10000 12000 14000

0 10 20 30 40 50 60 70

Test Time - hoursCumulative Permeation - mg. Low Temp 7 Psi

High Temp 7 Psi54 1999 Dodge Caravan Enhanced SHED SHED

Results Results Caniste r Permeation mg/day mg/day Loss

V eh Fuel Test Type Date Test# mg/hr (Raw) (Corrected) g

4 7.0 Static Perm 08/09/06 6912 50.3

Press. Incr. 0.0

Prs+Fuel Incr. 0.0

7.0 Dynamic RL 08/10/06 25636 184.6
HS 73.5
RL + HS 258.1

7.0 72 DHB 65-105 08/22/06 6919 Day 1 503.7 0.00 Day 2 454.0 0.00 Day 3 606.3 0.00

7.0 72 DHB 85-120 08/29/06 6922 Day 1 1070.9 0.00 Day 2 886.5 0.48 Day 3 1804.1 0.31

9.0 72 DHB 65-105 09/03/06 6926 Day 1 695.9 0.00 Day 2 556.7 1.19 Day 3 665.0 12.85

9.0 72 DHB 85-120 09/07/06 6927 Day 1 1396.4 23.79 Day 2 1175.1 71.43 Day 3 1114.9 80.49

Static 86 F Permeation

Vehicle 4 - 7 PSI

300 320 340 360 380 400 420 440

0 20 40 60 80 100 120

Test Time - minutesSHED Mass - mg Basic Permeation Rate at 86 50.3 mg/hr (1207 mg/day) Incremental Incr. w/ pressurized tank 0.0 mg/hr Incremental Incr. w/ Fuel Pump 'On' 0.0 m g /h r

Steady State

Permeation Pressurize

the Tank Power the Fuel Pump

Test 6912 

# Vehicle 455 Running Loss and Hot Soak

Vehicle 4 - 7.0 Psi

y = -0.0398x 2 + 5.5741x

R 2 = 0.9865 y = -0.0087x 2 + 2.3904x + 104.51

R 2 = 0.9004

0 50 100 150 200 250 300

0 20 40 60 80 100 120

Test Time - minutesCumulative Permeation - mg

Test 25636 Running Loss Hot Soak

Running Loss Std. =0.05 g/mi This Test = 0.009 g/mi

Diurnal Time Response
Vehicle 4 - 7.0 Psi : Repeat

60 65 70 75 80 85 90 95 100 105 110

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70

Test Time - hoursSHED AMbient Temperature - deg F

-20 -10 0 10 20 30 40 50 60 70 80Permeation - mg/hr SHED Ambient

Hourly Permeation

Test 691956 Dynamic Diurnal
Vehicle 4 - 7.0 Psi : Repeat

-20 -10

0 10 20 30 40 50 60 70 80

60 70 80 90 100 110

SHED Ambient temperature - deg FHourly Permeation - mg/hr Day 1
Day 2
Day 3

Test 6919

Diurnal Time Response

Vehicle 4 - 7.0 Psi

80 85 90 95 100 105 110 115 120 125

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70

Test Time - hoursSHED AMbient Temperature - deg F

-10 10 30 50 70 90 110Permeation - mg/hr SHED Ambient

Hourly Permeation

Test 692257 Dynamic Diurnal

Vehicle 4 - 7.0 Psi

-20

0 20 40 60 80 100 120

80 90 100 110 120

SHED Ambient temperature - deg FHourly Permeation - mg/hr Day 1
Day 2
Day 3

Test 6922

Canister Breakthrough and Temperature

Vehicle 4 - 7.0 PSI

80 85 90 95 100 105 110 115 120 125

0 10 20 30 40 50 60 70

Test Time - hrsTemperature - deg F

0 10 20 30 40 50 60 70 80 90 100Canister Breakthrough - grams SHED Ambient

Fuel Temp

Breakthrough

Test 692258 Diurnal Time Response

Vehicle 4 - 9.0 Psi

60 65 70 75 80 85 90 95 100 105 110

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70

Test Time - hoursSHED AMbient Temperature - deg F

-10 0 10 20 30 40 50 60 70 80 90Permeation - mg/hr SHED Ambient

Hourly Permeation

Test 6926

Dynamic Diurnal

Vehicle 4 - 9.0 Psi

-20

0 20 40 60 80 100

60 70 80 90 100 110

SHED Ambient temperature - deg FHourly Permeation - mg/hr Day 1
Day 2
Day 3

Test 692659 Canister Breakthrough and Temperature

Vehicle 4 - 9.0 PSI

60 65 70 75 80 85 90 95 100 105 110

0 10 20 30 40 50 60 70

Test Time - hrsTemperature - deg F

0 2 4 6 8 10 12 14 16 18Canister Breakthrough - grams SHED Ambient
Fuel Temp
Breakthrough

Test 6926

Diurnal Time Response

Vehicle 4 - 9.0 Psi

80 85 90 95 100 105 110 115 120 125

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70

Test Time - hoursSHED AMbient Temperature - deg F

-25 -5 15 35 55 75 95 115 135 155Permeation - mg/hr SHED Ambient

Hourly Permeation

Test 692760 Dynamic Diurnal

Vehicle 4 - 9.0 Psi

-20

0 20 40 60 80 100 120 140 160

80 90 100 110 120

SHED Ambient temperature - deg FHourly Permeation - mg/hr Day 1
Day 2
Day 3

Test 6927

Canister Breakthrough and Temperature

Vehicle 4 - 9.0 PSI

80 85 90 95 100 105 110 115 120 125

0 10 20 30 40 50 60 70

Test Time - hrsTemperature - deg F

0 50 100 150 200 250Canister Breakthrough - grams SHED Ambient

Fuel Temp

Breakthrough

Test 692761 Cumulative Permeation

Vehicle 4

0 500 1000 1500 2000 2500 3000 3500 4000 4500

0 10 20 30 40 50 60 70

Test Time - hoursCumulative Permeation - mg. Low Temp - 7 Psi
High Temp - 7 Psi
Low Temp - 9 Psi
High Temp - 9 Psi

Cumulative Permeation

Vehicle 4

0 500 1000 1500 2000 2500 3000 3500

0 10 20 30 40 50 60 70

Test Time - hoursCumulative Permeation - mg. Low Temp - 7 Psi

High Temp - 7 Psi62 2007 Ford Taurus LEV II SHED SHED

Results Results Canister Permeation mg/day mg/day Loss

V eh Fuel Test Type Date Test# mg/hr (Raw) (Corrected) g

5 7.0 Static Perm 08/30/06 6923 9.2

Press. Incr. 0.8

Prs+Fuel Incr. 6.8

7.0 Dynamic RL 09/07/06 25638 35.8
HS 0.5
RL + HS 36.3

7.0 72 DHB 65-105 09/09/06 6928 Day 1 108.4 0.00 Day 2 52.7 0.00 Day 3 92.9 0.00

7.0 72 DHB 65-105 09/15/06 6931 Day 1 101.5 0.00 Day 2 55.4 0.00 Day 3 95.4 0.00

7.0 72 DHB 85-120 09/19/06 6933 Day 1 196.9 0.00 Day 2 146.2 0.00 Day 3 134.2 0.00

Static 86 F Permeation

Vehicle 5 - 7 PSI

255 260 265 270 275 280

0 20 40 60 80 100 120

Test Time - minutesSHED Mass - mg Basic Permeation Rate at 86 9.2 mg/hr (221 mg/day) Incremental Incr. w/ pressurized tank 0.8 mg/hr (19 mg/day) Incremental Incr. w/ Fuel Pump 'On' 6.0 m g /hr ( 144 m g /da y)

Steady State

Permeation

Pressurize

the Tank Power the Fuel Pump

Test 6923 

# Vehicle 563 Running Loss and Hot Soak

Vehicle 5 - 7.0 Psi

y = -0.0145x 2 + 1.3049x

R 2 = 0.7662 y = 0.0003x 2 - 0.0278x + 34.63

R 2 = 0.0062

0 5 10 15 20 25 30 35 40 45 50

0 20 40 60 80 100 120

Test Time - minutesCumulative Permeation - mg

Test 25638 Running Loss Hot Soak

Running Loss Std. =0.05 g/mi This Test = 0.002 g/mi

Diurnal Time Response

Vehicle 5 - 7.0 Psi

60 65 70 75 80 85 90 95 100 105 110

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70

Test Time - hoursSHED AMbient Temperature - deg F

-15 -10 -5 0 5 10 15 20 25Permeation - mg/hr SHED Ambient

Hourly Permeation

Test 692864 Dynamic Diurnal

Vehicle 5 - 9.0 Psi

-20 -15 -10

-5 0 5 10 15 20 25

60 70 80 90 100 110

SHED Ambient temperature - deg FHourly Permeation - mg/hr Day 1
Day 2
Day 3

Test 6928

Diurnal Time Response

Vehicle 5 - 7.0 Psi

60 65 70 75 80 85 90 95 100 105 110

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70

Test Time - hoursSHED AMbient Temperature - deg F

-10 -5 0 5 10 15 20Permeation - mg/hr SHED Ambient

Hourly Permeation

Test 693165 Dynamic Diurnal

Vehicle 5 - 9.0 Psi

-10

-5 0 5 10 15 20

60 70 80 90 100 110

SHED Ambient temperature - deg FHourly Permeation - mg/hr Day 1
Day 2
Day 3

Test 6931

Diurnal Time Response

Vehicle 5 - 7.0 Psi

80 85 90 95 100 105 110 115 120 125

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70

Test Time - hoursSHED AMbient Temperature - deg F

-15 -10 -5 0 5 10 15 20 25 30Permeation - mg/hr SHED Ambient

Hourly Permeation

Test 693366 Dynamic Diurnal

Vehicle 5 - 9.0 Psi

-10

-5 0 5 10 15 20 25 30

80 90 100 110 120

SHED Ambient temperature - deg FHourly Permeation - mg/hr Day 1
Day 2
Day 3

Test 6933

Cumulative Permeation

Vehicle 5

0 100 200 300 400 500 600

0 10 20 30 40 50 60 70

Test Time - hoursCumulative Permeation - mg. Low Temp - 7 Psi

Low Temp - 7Psi Repeat

High Temp - 7 Psi67 1996 Chevrolet Cavalier SHED SHED

Results Results Caniste r Permeation mg/day mg/day Loss

V eh Fuel Test Type Date Test# mg/hr (Raw) (Corrected) g

6 7.0 Static Perm 09/27/06 6939 25.8

Press. Incr. 0.0

Prs+Fuel Incr. 15.8

7.0 Dynamic RL 09/27/06 25640 214.6
HS 56.1
RL + HS 270.8

7.0 24 DHB 65-105 10/19/06 6953 Day 1 477.3 375.6 0.00

7.0 24 DHB 85-120 10/24/06 6955 Day 1 468.2 372.0 0.00

9.0 24 DHB 65-105 11/02/06 6959 Day 1 569.2 468.5 0.00

9.0 24 DHB 85-120 11/08/06 6961 Day 1 785.1 685.4 18.92

Static 86 F Permeation

Vehicle 6 - 7 PSI

175 185 195 205 215 225 235 245 255 265

0 20 40 60 80 100 120

Test Time - minutesSHED Mass - mg Basic Permeation Rate at 86 25.8 mg/hr (619 mg/day) Incremental Incr. w/ pressurized tank 0.0 mg/hr

Incremental Incr. w/ Fuel Pum p 'On' 15.8 m g /hr ( 379 m g /da y)

Steady State

Permeation

Pressurize

the Tank Power the Fuel Pump

Test 6939 

# Vehicle 668 Running Loss and Hot Soak

Vehicle 6 - 7.0 Psi

y = -0.0127x 2 + 5.0669x

R 2 = 0.9945 y = -0.0031x 2 + 1.1342x + 183.94

R 2 = 0.8374

0 50 100 150 200 250 300

0 20 40 60 80 100 120

Test Time - minutesCumulative Permeation - mg

Test 25640 Running Loss Hot Soak

Running Loss Std. =0.05 g/mi This Test = 0.011 g/mi

Diurnal Time Response

Vehicle 6 - 7.0 Psi

60 65 70 75 80 85 90 95 100 105 110

0 2 4 6 8 10 12 14 16 18 20 22 24

Test Time - hoursSHED AMbient Temperature - deg F

-20 -10 0 10 20 30 40 50Corrected Permeation - mg/hr SHED Ambient

Hourly Permeation

Test 6953 Low Temp Diurnal69 Dynamic Diurnal

Vehicle 6 - 7.0 Psi

-5 0 5 10 15 20 25 30 35 40 45

60 70 80 90 100 110

SHED Ambient temperature - deg FHourly Permeation - mg/hr

Test 6953 Low Temp Diurnal

Non-Fuel Contaminant Cumulative Permeation

Vehicle 6 - 7.0 PSI

0 10 20 30 40 50 60

0 5 10 15 20 25

Test Time - hrsCumulative Permeation - mg R134a

Methanol Low Temp Diurnal

Test 695370 Effect of Non-Fuel Contaminants

Vehicle 6 - 7.0 PSI

0 100 200 300 400 500

0 5 10 15 20 25

Test Time - hrsCumulative Permeation - mg Raw SHED Mass

Corrected for R134a

Corrected for Methanol

Corrected SHED Mass Low Temp Diurnal

Test 6953

Diurnal Time Response

Vehicle 6 - 7.0 Psi

80 85 90 95 100 105 110 115 120 125

0 2 4 6 8 10 12 14 16 18 20 22 24

Test Time - hoursSHED AMbient Temperature - deg F

-5 0 5 10 15 20 25 30 35 40Corrected Permeation - mg/hr SHED Ambient

Hourly Permeation

Test 6955 High Temp Diurnal71 Dynamic Diurnal

Vehicle 6 - 7.0 Psi

-5 0 5 10 15 20 25 30 35 40

80 85 90 95 100 105 110 115 120 125

SHED Ambient temperature - deg FHourly Permeation - mg/hr

Test 6955 High Temp Diurnal

Non-Fuel Contaminant Cumulative Permeation

Vehicle 6 - 7.0 PSI

0 10 20 30 40 50 60 70 80

0 5 10 15 20 25

Test Time - hrsCumulative Permeation - mg R134a

Methanol High Temp Diurnal

Test 695572 Effect of Non-Fuel Contaminants

Vehicle 6 - 7.0 PSI

0 100 200 300 400 500

0 5 10 15 20 25

Test Time - hrsCumulative Permeation - mg Raw SHED Mass

Corrected for R134a

Corrected for Methanol

Corrected SHED Mass High Temp Diurnal

Test 6955

Diurnal Time Response

Vehicle 6 - 9.0 Psi

60 65 70 75 80 85 90 95 100 105 110

0 2 4 6 8 10 12 14 16 18 20 22 24

Test Time - hoursSHED AMbient Temperature - deg F

-20 -10 0 10 20 30 40 50 60Corrected Permeation - mg/hr SHED Ambient

Hourly Permeation

Test 6959 Low Temp Diurnal73 Dynamic Diurnal

Vehicle 6 - 9.0 Psi

-5 5 15 25 35 45 55

60 70 80 90 100 110

SHED Ambient temperature - deg FHourly Permeation - mg/hr

Test 6959 Low Temp Diurnal

Non-Fuel Contaminant Cumulative Permeation

Vehicle 6 - 9.0 PSI

-10

0 10 20 30 40 50 60 70

0 5 10 15 20 25

Test Time - hrsCumulative Permeation - mg R134a

Methanol Low Temp Diurnal

Test 695974 Effect of Non-Fuel Contaminants

Vehicle 6 - 9.0 PSI

0 100 200 300 400 500 600 700

0 5 10 15 20 25

Test Time - hrsCumulative Permeation - mg Raw SHED Mass

Corrected for R134a

Corrected for Methanol

Corrected SHED Mass Low Temp Diurnal

Test 6959

Diurnal Time Response

Vehicle 6 - 9.0 Psi

80 85 90 95 100 105 110 115 120 125

0 2 4 6 8 10 12 14 16 18 20 22 24

Test Time - hoursSHED AMbient Temperature - deg F

-10 0 10 20 30 40 50 60 70Corrected Permeation - mg/hr SHED Ambient

Hourly Permeation

Test 6961 High Temp Diurnal75 Dynamic Diurnal

Vehicle 6 - 9.0 Psi

-10

0 10 20 30 40 50 60 70

80 85 90 95 100 105 110 115 120 125

SHED Ambient temperature - deg FHourly Permeation - mg/hr

Test 6961 High Temp Diurnal

Non-Fuel Contaminant Cumulative Permeation

Vehicle 6 - 9.0 PSI

0 10 20 30 40 50 60 70 80 90 100

0 5 10 15 20 25

Test Time - hrsCumulative Permeation - mg R134a

Methanol High Temp Diurnal

Test 696176 Effect of Non-Fuel Contaminants

Vehicle 6 - 9.0 PSI

0 100 200 300 400 500 600 700 800 900

0 5 10 15 20 25

Test Time - hrsCumulative Permeation - mg Raw SHED Mass

Corrected for R134a

Corrected for Methanol

Corrected SHED Mass High Temp Diurnal

Test 6961

Canister Breakthrough and Temperature

Vehicle 6 - 9.0 PSI

80 85 90 95 100 105 110 115 120 125

0 5 10 15 20 25

Test Time - hrsTemperature - deg F

0 2 4 6 8 10 12 14 16 18 20Canister Breakthrough -grams SHED Ambient

Fuel Temp

Breakthrough

Test 696177 Cumulative Permeation - Corrected Mass

Vehicle 6

0 100 200 300 400 500 600 700 800

0 5 10 15 20 25

Test Time - hoursCumulative Permeation - mg. Low Temp - 7 Psi
High Temp - 7 Psi
Low Temp - 9 Psi
High Temp - 9 Psi78 1996 Chevrolet Cavalier Enhanced (with implanted leak) SHED SHED
Results Results Canister mg/hr mg/hr mg/day mg/day Loss

V eh Fuel Test Type Date Test# (Raw) (Corrected) (Raw) (Corrected) g

7 7.0 Static Cap (.020") 11/14/06 6963 59.0

Fuel Incr. 2358.3

7.0 Dynamic RL 11/17/06 25642 258.7 227.6
HS 149.3 129.0
RL + HS 408.1 356.6

7.0 24 DHB 65-105 11/21/06 6964 Day 1 21036 20704 0

7.0 24 DHB 85-120 11/30/06 6966 Day 1 27824 27384 0 Permeation

Static 86 F Permeation
Vehicle 7 (with implanted leak) - 7 PSI

0 200 400 600 800 1000 1200 1400 1600

0 20 40 60 80 100 120

Test Time - minutesSHED Mass - mg Basic Permeation Rate at 86 59.0 mg/hr (1416 mg/day) Incremental Incr. w/ Fuel Pump 'On' 2417.3 mg/hr

Steady State

Permeation Power the Fuel Pump

Test 6963

Vehicle 6 

# Vehicle 779 Running Loss and Hot Soak Vehicle 7 (with implanted leak) - 7.0 Psi

y = -0.0525x 2 + 6.756x

R 2 = 0.943 y = -0.0453x 2 + 8.8502x - 88.065

R 2 = 0.929

0 50 100 150 200 250 300 350 400 450 500

0 20 40 60 80 100 120

Test Time - minutesCumulative Corrected Permeation - mg

Test 25642 Running Loss Hot Soak

Running Loss Std. =0.05 g/mi This Test = .012 g/mi

Diurnal Time Response Vehicle 7 (with implanted leak) - 7.0 Psi

60 65 70 75 80 85 90 95 100 105 110

0 2 4 6 8 10 12 14 16 18 20 22 24

Test Time - hoursSHED AMbient Temperature - deg F

-500 0 500 1000 1500 2000 2500 3000Corrected Permeation - mg/hr SHED Ambient

Hourly Permeation

Test 6964 Low Temp Diurnal80 Dynamic Diurnal Vehicle 7 (with implanted leak) - 7.0 Psi

-500 0 500 1000 1500 2000 2500 3000

60 70 80 90 100 110

SHED Ambient temperature - deg FHourly Permeation - mg/hr

Test 6964 Low Temp Diurnal

Non-Fuel Contaminant Cumulative Permeation
Vehicle 7 (with implanted leak) - 7.0 PSI

0 50 100 150 200 250

0 5 10 15 20 25

Test Time - hrsCumulative Permeation + Leak - mg R134a

Methanol Low Temp Diurnal

Test 696481 Effect of Non-Fuel Contaminants
Vehicle 7 (with implanted leak) - 7.0 PSI

0 5000 10000 15000 20000 25000

0 5 10 15 20 25

Test Time - hrsCumulative Permeation + Leak - mg Raw SHED Mass

Corrected for R134a

Corrected for Methanol

Corrected SHED Mass Low Temp Diurnal

Test 6964

Diurnal Time Response Vehicle 7 (with implanted leak) - 7.0 Psi

80 85 90 95 100 105 110 115 120 125

0 2 4 6 8 10 12 14 16 18 20 22 24

Test Time - hoursSHED AMbient Temperature - deg F

-1000 0 1000 2000 3000 4000 5000 6000Corrected Permeation - mg/hr SHED Ambient

Hourly Permeation

Test 6966 High Temp Diurnal82 Dynamic Diurnal Vehicle 7 (with implanted leak) - 7.0 Psi

-1000 0 1000 2000 3000 4000 5000 6000

80 85 90 95 100 105 110 115 120 125

SHED Ambient temperature - deg FHourly Permeation - mg/hr

Test 6966 High Temp Diurnal

Non-Fuel Contaminant Cumulative Permeation
Vehicle 7 (with implanted leak) - 7.0 PSI

0 50 100 150 200 250 300 350

0 5 10 15 20 25

Test Time - hrsCumulative Permeation - mg R134a

Methanol High Temp Diurnal

Test 696683 Effect of Non-Fuel Contaminants
Vehicle 7 (with implanted leak) - 7.0 PSI

0 5000 10000 15000 20000 25000 30000 35000

0 5 10 15 20 25

Test Time - hrsCumulative Permeation - mg Raw SHED Mass

Corrected for R134a

Corrected for Methanol

Corrected SHED Mass High Temp Diurnal

Test 6966

Cumulative Permeation - Corrected Mass
Vehicle 7 (with implanted leak)

0 5000 10000 15000 20000 25000 30000 35000

0 5 10 15 20 25

Test Time - hoursCumulative Permeation + Leak - mg. Low Temp - 7 Psi

High Temp - 7 Psi84 1996 Ford Explore r SHED SHED

Results Results Caniste r Permeation mg/day mg/day Loss

V eh Fuel Test Type Date Test# mg/hr (Raw) (Corrected ) g

8 7.0 Static Perm 10/10/06 6949 6.8

Press. Incr. 2.3

Prs+Fuel Incr. 0.3

7.0 Dynamic RL 10/12/06 25641 171.3
HS 73.8
RL + HS 245.0

7.0 24 DHB 65-105 10/21/06 6954 Day 1 279.7 133.1 0.00

7.0 24 DHB 85-120 10/26/06 6956 Day 1 298.0 235.4 0.00

9.0 24 DHB 65-105 10/28/06 6957 Day 1 227.5 150.4 0.00

9.0 24 DHB 85-120 11/09/06 6962 Day 1 346.2 254.6 128.68

Static 86 F Permeation

Vehicle 8 - 7 PSI

210 212 214 216 218 220 222 224 226 228 230

0 20 40 60 80 100 120

Test Time - minutesSHED Mass - mg Basic Permeation Rate at 86 6.8 mg/hr (164 mg/day) Incremental Incr. w/ pressurized tank 2.3 mg/hr Incremental Incr. w/ Fuel Pump 'On' 0.3 mg/hr

Steady State

Permeation Pressurize

the Tank
Power the Fuel Pump

Test 6949 

# Vehicle 885 Running Loss and Hot Soak

Vehicle 8 - 7.0 Psi

y = 0.0126x 2 + 2.7798x

R 2 = 0.975 y = -0.0152x 2 + 3.1951x + 74.852

R 2 = 0.8487

0 50 100 150 200 250 300

0 20 40 60 80 100 120

Test Time - minutesCumulative Permeation - mg

Test 25641 Running Loss Hot Soak

Running Loss Std. =0.05 g/mi This Test = 0.009 g/mi

Diurnal Time Response

Vehicle 8 - 7.0 Psi

60 65 70 75 80 85 90 95 100 105 110

0 2 4 6 8 10 12 14 16 18 20 22 24

Test Time - hoursSHED AMbient Temperature - deg F

-4 -2 0 2 4 6 8 10 12 14Corrected Permeation - mg/hr SHED Ambient

Hourly Permeation

Test 6954 Low Temp Diurnal86 Dynamic Diurnal

Vehicle 8 - 7.0 Psi

-4 -2 0 2 4 6 8 10 12 14

60 70 80 90 100 110

SHED Ambient temperature - deg FCorrected Hourly Permeation - mg/hr

Test 6954 Low Temp Diurnal

Non-Fuel Contaminant Cumulative Permeation

Vehicle 8 - 7.0 PSI

-20

0 20 40 60 80 100 120 140 160 180 200

0 5 10 15 20 25

Test Time - hrsCumulative Permeation - mg R134a

Methanol Low Temp Diurnal

Test 695487 Effect of Non-Fuel Contaminants

Vehicle 8 - 7.0 PSI

0 50 100 150 200 250 300

0 5 10 15 20 25

Test Time - hrsCumulative Permeation - mg Raw SHED Mass

Corrected for R134a

Corrected for Methanol

Corrected SHED Mass Low Temp Diurnal

Test 6954

Non-Fuel Component Cumulative Permeation
Vehicle 8 - 7 psi

-20

0 20 40 60 80 100 120 140 160 180 200

0 5 10 15 20 25

Test Time - hrs.Cumulative Permeation - mg R134a

Methanol

Ethanol Low Temperature Diurnal

Test 695488 Diurnal Time Response

Vehicle 8 - 7.0 Psi

80 85 90 95 100 105 110 115 120 125

0 2 4 6 8 10 12 14 16 18 20 22 24

Test Time - hoursSHED AMbient Temperature - deg F

-10 -5 0 5 10 15 20 25 30Corrected Permeation - mg/hr SHED Ambient

Hourly Permeation

Test 6956 High Temp Diurnal

Dynamic Diurnal

Vehicle 8 - 7.0 Psi

-10

-5 0 5 10 15 20 25 30

80 85 90 95 100 105 110 115 120 125

SHED Ambient temperature - deg FCorrected HourlyPermeation - mg/hr

Test 6956 High Temp Diurnal89 Non-Fuel Contaminant Cumulative Permeation

Vehicle 8 - 7.0 PSI

0 5 10 15 20 25 30 35 40 45 50

0 5 10 15 20 25

Test Time - hrsCumulative Permeation - mg R134a

Methanol High Temp Diurnal

Test 6956

Effect of Non-Fuel Contaminants

Vehicle 8 - 7.0 PSI

0 50 100 150 200 250 300 350

0 5 10 15 20 25

Test Time - hrsCumulative Permeation - mg Raw SHED Mass

Corrected for R134a

Corrected for Methanol

Corrected SHED Mass High Temp Diurnal

Test 695690 Diurnal Time Response

Vehicle 8 - 9.0 Psi

60 65 70 75 80 85 90 95 100 105 110

0 2 4 6 8 10 12 14 16 18 20 22 24

Test Time - hoursSHED AMbient Temperature - deg F

-10 -5 0 5 10 15 20 25Corrected Permeation - mg/hr SHED Ambient

Hourly Permeation

Test 6957 Low Temp Diurnal

Dynamic Diurnal

Vehicle 8 - 9.0 Psi

-10

-5 0 5 10 15 20 25

60 70 80 90 100 110

SHED Ambient temperature - deg FCorrected Hourly Permeation - mg/hr

Test 6957 Low Temp Diurnal91 Non-Fuel Contaminant Cumulative Permeation

Vehicle 8 - 9.0 PSI

0 10 20 30 40 50 60 70

0 5 10 15 20 25

Test Time - hrsCumulative Permeation - mg R134a

Methanol Low Temp Diurnal

Test 6957

Effect of Non-Fuel Contaminants

Vehicle 8 - 9.0 PSI

0 50 100 150 200 250

0 5 10 15 20 25

Test Time - hrsCumulative Permeation - mg Raw SHED Mass

Corrected for R134a

Corrected for Methanol

Corrected SHED Mass Low Temp Diurnal

Test 695792 Diurnal Time Response

Vehicle 8 - 9.0 Psi

80 85 90 95 100 105 110 115 120 125

0 2 4 6 8 10 12 14 16 18 20 22 24

Test Time - hoursSHED AMbient Temperature - deg F

-5 0 5 10 15 20 25 30Corrected Permeation - mg/hr SHED Ambient

Hourly Permeation

Test 6962 High Temp Diurnal

Dynamic Diurnal

Vehicle 8 - 9.0 Psi

-10

-5 0 5 10 15 20 25 30

80 85 90 95 100 105 110 115 120 125

SHED Ambient temperature - deg FCorrected Hourly Permeation - mg/hr

Test 6962 High Temp Diurnal93 Non-Fuel Contaminant Cumulative Permeation

Vehicle 8 - 9.0 PSI

0 10 20 30 40 50 60 70 80 90

0 5 10 15 20 25

Test Time - hrsCumulative Permeation - mg R134a

Methanol High Temp Diurnal

Test 6957

Effect of Non-Fuel Contaminants

Vehicle 8 - 9.0 PSI

0 50 100 150 200 250 300 350 400

0 5 10 15 20 25

Test Time - hrsCumulative Permeation - mg Raw SHED Mass

Corrected for R134a

Corrected for Methanol

Corrected SHED Mass High Temp Diurnal

Test 696294 Cumulative Permeation - Corrected Mass

Vehicle 8

0 50 100 150 200 250 300

0 5 10 15 20 25

Test Time - hoursCumulative Permeation - mg. Low Temp - 7 Psi

High Temp - 7 Psi

Low Temp - 9 Psi

High Temp - 9 Psi

Temperature Effect

RVP Effect95 1995 Plymouth Neon Pre-Enhanced SHED SHED

Results Results Canister mg/hr mg/hr mg/day mg/da y Loss

V eh Fuel Test Type Date Test# (Raw) (Corrected ) (Raw) (Corrected ) g

9 7.0 Static Perm 01/09/07 6975 37.8 27.3

Press. Incr. 0.0 0.0

Prs+Fuel Incr. 0.4 8.8

7.0 Dynamic RL 12/21/06 25646 209.3
HS 66.0
RL + HS 275.3

7.0 24 DHB 65-105 01/03/07 6973 Day 1 1633.6 546.7 0.13

7.0 24 DHB 85-120 01/06/07 6974 Day 1 1053.8 953.5 9.42 Permeation

Static 86 F Permeation

Vehicle 9 - 7 PSI

0 10 20 30 40 50 60 70

0 20 40 60 80 100 120

Test Time - minutesCorrected SHED Mass - mg Basic Permeation Rate at 86 27.3 mg/hr (907 mg/day) Incremental Incr. w/ pressurized tank 0.0 mg/hr Incremental Incr. w/ Fuel Pump 'O n' 8.8 mg/hr

Steady State

Permeation

Pressurize

the Tank Power the Fuel Pump

Test

6975b 

# Vehicle 996 Running Loss and Hot Soak

Vehicle 9 - 7.0 Psi

y = -0.0522x 2 + 6.7607x

R 2 = 0.9763 y = -0.0084x 2 + 2.3146x + 122.92

R 2 = 0.944

0 50 100 150 200 250 300 350

0 20 40 60 80 100 120

Test Time - minutesCumulative Permeation - mg

Test 25646 Running Loss Hot Soak

Running Loss Std. =0.05 g/mi This Test = 0.011 g/mi

Diurnal Time Response

Vehicle 9 - 7.0 Psi

60 65 70 75 80 85 90 95 100 105 110

0 2 4 6 8 10 12 14 16 18 20 22 24

Test Time - hoursSHED AMbient Temperature - deg F

-30 -20 -10 0 10 20 30 40 50 60Corrected Permeation - mg/hr SHED Ambient

Hourly Permeation

Test 6973 Low Temp Diurnal97 Dynamic Diurnal

Vehicle 9 - 7.0 Psi

-30 -20 -10

0 10 20 30 40 50 60

60 70 80 90 100 110

SHED Ambient temperature - deg FCorrected Hourly Permeation - mg/hr

Test 6973 Low Temp Diurnal

Non-Fuel Contaminant Cumulative Permeation

Vehicle 9 - 7.0 PSI

-500 0 500 1000 1500 2000 2500 3000 3500 4000

0 5 10 15 20 25

Test Time - hrsCumulative Permeation - mg Fuel Equivalent R134a

Actual R134a

Fuel Equivalent Methanol

Actual Methanol Low Temp Diurnal

Test 697398 Effect of Non-Fuel Contaminants

Vehicle 9 - 7.0 PSI

0 200 400 600 800 1000 1200 1400 1600 1800

0 5 10 15 20 25

Test Time - hrsCumulative Permeation - mg Raw SHED Mass

Corrected for R134a

Corrected for Methanol

Corrected SHED Mass Low Temp Diurnal

Test 6973

Diurnal Time Response

Vehicle 9 - 7.0 Psi

80 85 90 95 100 105 110 115 120 125

0 2 4 6 8 10 12 14 16 18 20 22 24

Test Time - hoursSHED AMbient Temperature - deg F

-10 0 10 20 30 40 50 60 70 80 90Corrected Permeation - mg/hr SHED Ambient

Hourly Permeation

Test 6974 High Temp Diurnal99 Dynamic Diurnal

Vehicle 9 - 7.0 Psi

-10

0 10 20 30 40 50 60 70 80 90

80 85 90 95 100 105 110 115 120 125

SHED Ambient temperature - deg FCorrected Hourly Permeation - mg/hr

Test 6974 High Temp Diurnal

Non-Fuel Contaminant Cumulative Permeation

Vehicle 9 - 7.0 PSI

0 50 100 150 200 250 300 350

0 5 10 15 20 25

Test Time - hrsCumulative Permeation - mg Fuel Equivalent R134a

Actual R134a

Fuel Equivalent Methanol

Actual Methanol High Temp Diurnal

Test 6974100 Effect of Non-Fuel Contaminants

Vehicle 9 - 7.0 PSI

0 200 400 600 800 1000 1200

0 5 10 15 20 25

Test Time - hrsCumulative Permeation - mg Raw SHED Mass

Corrected for R134a

Corrected for Methanol

Corrected SHED Mass High Temp Diurnal

Test 6974

Cumulative Permeation - Corrected Mass

Vehicle 9

0 200 400 600 800 1000 1200

0 5 10 15 20 25

Test Time - hoursCumulative Permeation - mg. Lo Temp 7psi : Total SHED Lo Temp 7psi : Non-Ethanol Hi Temp : Total SHED
Hi Temp :Non-Ethanol

Ethanol Effect101 1992 Toyota Camry SHED SHED

Results Results Canister Permeation mg/day mg/day Loss

V eh Fuel Test Type Date Test# mg/hr (Raw) (Corrected) g

10 7.0 Static Perm 02/07/07 6977 80.5

Press. Incr. 13.2

Prs+Fuel Incr. 0.0

7.0 Dynamic RL 02/07/07 25648 1375.0
HS 977.1
RL + HS 2352.1

7.0 24 DHB 65-105 02/21/07 6984 3831.3 3773.7 0.00 Day 1

7.0 24 DHB 65-105 02/23/07 6985 3150.4 3107.8 0.00 Day 1

7.0 24 DHB 85-120 02/16/07 6983 1655.8 1689.3 4.98 Day 1

Static 86 F Permeation

Vehicle 10 - 7 PSI

300 350 400 450 500 550 600 650 700

0 20 40 60 80 100 120

Test Time - minutesCorrected SHED Mass - mg Basic Permeation Rate at 86 80.5 mg/hr (1932 mg/day) Incremental Incr. w/ pressurized tank 13.2 mg/hr Incremental Incr. w/ Fuel Pump 'O n' 0.0 mg/hr

Steady State

Permeation

Pressurize

the Tank Power the Fuel Pump

Test 6977 

# Vehicle 10102 Running Loss and Hot Soak

Vehicle 10 - 7 Psi

y = 0.4252x 2 + 8.0915x

R 2 = 0.9989 y = -0.2872x 2 + 60.317x - 842.14

R 2 = 0.9979

0 500 1000 1500 2000 2500

0 20 40 60 80 100 120

Test Time - minutesCumulative Permeation - mg

Test 25648 Running Loss Hot Soak

Running Loss Std. =0.05 g/mi This Test = 0.025 g/mi

Diurnal Time Response

Vehicle 10 - 7 Psi

80 85 90 95 100 105 110 115 120 125

0 5 10 15 20 25

Test Time - hoursSHED AMbient Temperature - deg F

-50 0 50 100 150 200Corrected Permeation - mg/hr SHED Ambient

Hourly Permeation

Test103 Dynamic Diurnal

Vehicle 10 - 7 Psi

-10 40 90 140 190 240

80 85 90 95 100 105 110 115 120 125

SHED Ambient temperature - deg FCorrected Hourly Permeation - mg/hr

Test 6983

Diurnal Time Response

Vehicle 10 - 7 Psi

60 65 70 75 80 85 90 95 100 105 110

0 5 10 15 20 25

Test Time - hoursSHED AMbient Temperature - deg F

-100 0 100 200 300 400 500 600 700Corrected Permeation - mg/hr SHED Ambient

Hourly Permeation

Test 6984104 Dynamic Diurnal

Vehicle 10 - 7 Psi

-100 0 100 200 300 400 500 600 700

60 70 80 90 100 110

SHED Ambient temperature - deg FCorrected Hourly Permeation - mg/hr

Test 6984

Diurnal Time Response

Vehicle 10 - 7 Psi

60 65 70 75 80 85 90 95 100 105 110

0 5 10 15 20 25

Test Time - hoursSHED AMbient Temperature - deg F

-100 0 100 200 300 400 500 600Corrected Permeation - mg/hr SHED Ambient

Hourly Permeation

Test 6984105 Dynamic Diurnal

Vehicle 10 - 7 Psi

-100 0 100 200 300 400 500 600

60 70 80 90 100 110

SHED Ambient temperature - deg FCorrected Hourly Permeation - mg/hr

Test 6985

Cumulative Permeation

Vehicle 10

0 500 1000 1500 2000 2500 3000 3500 4000 4500

0 5 10 15 20 25

Test Time - hoursCumulative Permeation - mg. Low Temp - 7 Psi

Low Temp - 7 psi Repeat

High Temp - 7 psi