P.1 

OAR Box 1147 

Prepped by Ollie Stewart 

Document Number: 

218)IV-E-92 

Docket Number: 

A-87-11 

Printed 4/22/2008 2:42:58 PM Sheet 218 of 242 
P.2 

REFUELING EMISSION CONTROLS 

A BRIEFING FOR THE NATIONAL 

HIGHWAY TRAFFIC SAFETY ADMINISTRATION 

APRIL 21, 1989 

by 

ENVIRONMENTAL PROTECTION AGENCY 

OFFICE OF MOBILE SOURCES 
P.3 

OVERVIEW OF THE BRIEFING 

• Rationale for controls 

• Onboard control description 

• Onboard control and vehicle safety 

-2-
P.4 

RATIONALE FOR CONTROLS 

• Ozone formation and nonattainment 

• Why control refueling emissions? 

• Why is onboard the preferred option? 

-3-
P.5 

OZONE FORMATION 

Ozone is an odorless, highly reactive gas vhich is main 

component of smog 

Ozone is a pulmonary irritant that decreases ability of 

lungs to function properly 

Ozone is formed in a complex photochemical reaction 

involving sunlight, oxides of nitrogen (NOx) and volatile 

organic compounds (VOC) 

The chief vay to control ozone is to reduce VOC emissions 

Large variety of sources but main ones are transportation 

and industrial processes 

-4-
P.6 

OZONE NONATTAINMENT 

Ozone is the most pervasive air pollution problem facing 

the nation today (see Figure 1) 

Preliminary ozone data for 1988 indicates 81 nonattainment 

areas affecting more than 100 million people 

Many areas are expected to remain in nonattainment despite 

many years of Federal, State, and local control efforts 

Reductions of from 10 percent to nearly 70 percent vill be 

needed to bring all areas into compliance (see Figure 2) 

-5-
P.7 

- 6 -
Figure 2 

i 

i 

APPROXIMATE PERCENT REDUCTION NECESSARY 

FOR OZONE NAAQS ATTAINMENT 

z 

o 

io 

Q 

LU 

DC 

O 

o 

> 

70 

60 -

50 

40 

30 

20 -

10 -

^fflE 

I II I II I II I BBEE * % I I III I I 11 I I I I I I I I I I I 1 ^ 

% 

~& r 

NUMBER OF CITIES 

• * " 80 

00 
P.9 

WHY CONTROL REFUELING EMISSIONS? 

• Provides a 2 to 3 percent reduction in VOC emissions 

• Fev remaining VOC control strategies can provide more 

reduction; most are less 

• Reductions can be achieved cost effectively vhen compared 

to other available control alternatives 

• Reduces exposure to toxic vapors during refueling -

benzene is a knovn human carcinogen and gasoline vapors in 

general are a toxic concern 

• Annual cancer incident reduction estimates for controlling 

refueling emissions are 4 to 42 depending on vhich 

compounds in gasoline vapors are considered carcinogenic 

-8-
P.10 

WHY EPA PROPOSED ONBOARD 

Onboard is superior on grounds of general economic 

efficiency: 

Onboard is more cost effective than Stage II - net 

savings for onboard, $1000 per ton for Stage II 

Long-term VOC reduction is greater vith onboard due 

to higher in-use control efficiency and lack of 

exemptions, After full implementation, onboard gets 

89 percent of refueling emissions in the NA areas; 

Stage II gets 48-66 percent (assuming Clean Air Act 

exemption levels) 

Onboard raises fever equity issues than Stage II: 

Onboard involves a more equitable distribution of 

costs than Stage II (everyone pays a little versus 

some service stations paying a lot) and avoids 

closure of marginal service stations 

Stage II vould have adverse effects on stations just 

vithin the boundary of non-attainment areas relative 

to their uncontrolled competition 

Stage II vould have adverse effects on controlled 

stations near the exemption cut-off level relative 

to their uncontrolled counterparts 

-9a-
P.11 

• Onboard provides benefits not achievable by a limited 

Stage II program: 

Onboard provides automatic coverage for marginal 

attainment areas and addresses regional ozone and 

ozone precursor transport concerns 

Onboard is a nationvide program that provides 

important ozone benefits in attainment areas and 

direct health benefits throughout the country 

VOC emissions reductions in attainment areas have 

value 

* Agricultural and ecological impacts, materials 

damage, and effects on visibility 

Cancer risk reductions throughout nation have value 

* Estimated incidences for benzene and gas vapor 

reduced from 131 to 58 

* Estimated incidences for benzene and > C-6 gas 

vapor fraction reduced from 42 to 17 

-9b-
P.12 

Onboard effectiveness is less vulnerable to acceptance, 

implementation and enforcement difficulties: 

Onboard systems require no maintenance and can be 

enforced vith existing mechanisms. Stage II systems 

are effective only if their maintenance is insured 

thru a vigorous government enforcement presence, 

Thus Stage II requires a long term resource 

intensive government (State and Federal) commitment 

to enforcement 

Onboard avoids consumer involvement in the control 

process, Stage II is politically unpopular because 

it requires consumer involvement (compare to I/M) 

For non-attainment areas, Stage II vould have to be 

implemented thru SIP process and ve expect 

significant resistance at the State level, This 

vould require EPA imposition of sanctions and 

possible EPA promulgation, both of vhich are time 

consuming and politically unpopular 

-9c-
P.13 

ONBOARD CONTROL SYSTEM DESCRIPTION 

• Fuel systems prior to evaporative emission controls 

• Evaporative control system 

• Onboard control system 

-10-
FUEL SYSTEMS PRIOR TO CONTROLS (PRE-1972) 

Fuel system emission sources: fuel metering system 

(carburetor) and fuel tank (see Figure 3) 

Main source of fuel metering emissions is carburetor float 

bovl vent - vented to engine compartment or carburetor 

inlet/air cleaner 

Fuel tanks vere vented to the atmosphere either through 

the filler cap or a vent tube vith an outlet under the 

body of the car 

-11-
P.15 

FUE:I_ 

Figure 3 

.YSTEMS F-RIOR TO COMTROI 

BOWL VENT CONFIGURATIONS 

TYPICAL TANK CONFIGURATION 

CAP •*£ RUER TUBE 

FUEL GAUGE (TANK UNIT) 

-12 -
EVAPORATIVE CONTROL SYSTEM 

Controls required on Federal vehicles in 1972 

Control system description (see Figure 4): 

Prevents vapors from being vented to the atmosphere 

(from fuel metering system and fuel tank) 

Routes vapors to a carbon canister 

Restores capacity of canister by purging stored 

vapors and burning them in the engine as fuel 

-13-
Figur e A 

Typical Current Evaporative System 

PRESSURE/VACUUM 

,L RELIEF CAP 

i 

EXTERNAL VENT LINE 

FLOAT/ROLLOVER 

VALVE 

3/8" DIA. 

8' LONG 

# 

.05" DIA. LIMITING 

ORIFICE 

14 GALLON FUEL TANK 

PURGE VALVE 

1 LITER 

CARBON 

CANISTER 

TO PURGE 

INDUCTION 

POINT 
P.18 

ONBOARD CONTROL SYSTEMS 

Onboard systems perform the same three basic functions as 

evaporative systems: 

Prevents vapors from venting directly to atmosphere 

during refueling 

Routes vapors to a carbon canister 

Restores capacity of canister by purging stored 

vapors and burning them in the engine as fuel 

A single integrated system can be used to control both 

evaporative and refueling emissions (see Figure 5) 

The folloving system modifications are necessary: 

Addition of a fillneck seal to prevent vapors from 

escaping during refueling 

Larger vapor line, rollover valve, and canister to 

handle additional refueling emissions 

-15-
Figure 5 

Onboard Plus Evaporative System 

PRESSURE/VACUUM 

RELIEF CAP 

NO 

EXTERNAL 

VENT LINE 

I 

SHORTER 

VAPOR LINE 

V 

MODIFIE

v

D 

\ 

FLOAT/ROLLOVER 

VALVE 

V 

ANTI - SPITBACK 

VALVE 

# 

PURGE VALVE 

TO PURGE 

INDUCTION 

POINT 

ENLARGED 

CARBON 

CANISTER 

FUEL TANK 
ONBOARD CONTROLS AND VEHICLE SAFETY 

• Background 

• EPA's response to NPRM safety comments 

• Onboard vehicle development 

-17-
P.21 

BACKGROUND 

Section '202(a)(6) of the Clean Air Act requires EPA to 

consult vith the Secretary of Transportation regarding 

onboard safety 

Consultation process began in Spring of 1986 - concerns 

centered on leadtime and a potential for an unquantified 

increase in risk 

EPA prepared safety study in Spring of 1987; key 

conclusions: 

Onboard controls are extensions of evap controls 

Straightforvard solutions exist to problems 

No increase in risk need occur 

Onboard NPRM published August, 1987 - commenters believed 

onboard vill increase fuel system complexity vhich in turn 

increases risk 

-18-
P.22 

EPA'S RESPONSE TO NPRM SAFETY COMMENTS 

• Revieved current evaporative system designs and in-use 

safety 

• Performed a fuel system comparative risk analysis (FMEA) 

• Assessed service station refueling risk and incidence-of 

siphoning-related gasoline ingestions - both vould be 

reduced vith onboard refueling controls 

• Developed a simplified onboard control system 

-19-
P.23 

REVIEW OF CURRENT EVAPORATIVE SYSTEM DESIGNS 

• Current vehicles show a vide range in design complexity 

(see Figures 6a-6d) 

• Over time, systems have become more complex (e.g., 

addition of fuel injection) 

• Current evaporative systems incorporate many features 

characterized as unsafe for onboard 

Valves on fillneck 

Plastic fillneck parts 

More tank connections 

Enlarged valve orifices 

• Unable to detect a relationship betveen fuel system 

complexity and reduced safety among current production 

systems 

-20-
Figure 6a 

Range Rover 

KEY TO DIAGRAM 

1. Charcoal cmbter 

2. Air Wet to canister 

3. Purge Ine to plenum chamber 

4. Connector hoses wHh restrictors 

5. Restrictor In purge Une 

6. Fud expansion tank 

7. Fud vapour pipe from manifold 

6. Breather hose with anti-surge valve 

9. Fud tank flOer neck 

10. Fffler neck breather hose 

11. Manifold 

12. Fud vapour pipes from fud tank (3 off) 

13. Pressure rdief valve and hose 

14. Fud tank 

15. Float/koOover valve 

16. Grommet 

-21 -
Figure 6b 

Ford Festiva 

P.25 

FUEL TANK 

SEPARATOR 

FUEL 

SUPPLY VAPOR 

LINE UNE 

S& ''"' 

FUEL 

VAPOR 

STORAGE 

CANISTER 

FUEL 

F1LTB1 

FUEL 

RETURN 

LINE 

ROLLOVER 

VENT 

VALVE 

-22 -
P.26 

FUELTANK 

REMOVAL AND INST; 

Figure 6c 

Chrysler Conquest 

14-79 

N140A--

Pra-ramoval Operation 

• Release of Residual Pressure 

from Fuel High Pressure Hose 

(Refer to P. 14-38.) 

Draining Fuel 

Post-installation Operation 

• Replenishment of Fue! 

1.0 Nm 

0.7ftlbs. 

25-30 Nm 

18-22 ft lbs. 13 

^••noval steps 

15-20 Nm 

11-18ftH». 

1. High floor side panel 

2. Fuel pipe cover 

3. Fuel pump'connector connection 

4. Fuel tank cap 

5. Drain plug 

6. Fuel gauge unit connector connection 

7. Fuel high pressure hose connection 

8. Return hose 

9. Vapor hose 

10. Fuel filler hose 

11. Fuel filler neck 

12. Fuel tank 

13. Electrical fuel pump 

14. -Separator tank 

15. Fuel gauge unit 

16. Pipe assembly 

17. In-tank fuel filter 

NOTE 

(1) Reverse the removal procedures to reinstall. 

(2) »*. Refer to "Service Points of Installation". 

-23-
P.27 

14*76 

FUEL TANK 

REMOVAL AND I 

Prt-ramoval Operation 

• Draining of theruej. 

Figure 6d 

Mitsubishi Mantero 

Post-installation Oparatlon 

• Supplying of the Fuel. | 

25-30 Nm 

18-22 ftlbt. 

15-20 Nm 

11-14 ft.lds 

OlWfM 

Removal steps 

1. Drain plug 

2. Fuel filler cap 

3* Fuel filler hose protector 

4. Vapor hose 

5. Check valve 

6. Overfill limiter (Two-way valvel 

7. Clamp assembly 

8. Fuel filler hose 

9. Breather hose 

10. Packing 

11. Fuel filler neck 

12. Main hose 

••-«• 13. Return hose 

» « 

» « 

4 Fuel gauge unit connector connection 

5. Fuel tank assembly mounting nuts 

6 F-del tank 

7 Pipe assembly 

5 Seoarator tanks 

3 Fuel tank protector 

•.OTE ., 

' • Reverse the removal procedures to reinstall _ 

2) » « Refer to Service Points of Installation 

-£*— 
P.28 

FUEL SYSTEM COMPARATIVE RISK ANALYSIS 

NHTSA; NTSB, and others suggested that EPA perform a fuel 

system comparative risk assessment (FMEA) 

EPA contracted with Battelle1s transportation safety group 

to perform analysis 

In September 1988, Battelle completed an independent study 

of risk of vehicle fire for ten different vehicle fuel 

system designs (included both stock and various onboard 

design configurations) 

Battelle has briefed NHTSA, NTSB, MVMA, AIA, and others 

Key conclusions: 

Risk of fires are remote in all cases 

Level of risk is not greatly different among cases 

Onboard systems have relatively less overall risk 

than stock systems 

-25-
SIMPLE ONBOARD CONTROL SYSTEM DEVELOPMENT 

Goal was an integrated system no more complex than a stock 

vehicle evaporative system (see Figures 4 and 5) 

First system on GM A-body (Oldsmobile Cutlass) fuel 

system 

Second system on Ford Taurus fuel system 

Filled well, controlled emissions, and eliminated fuel 

spitback under wide range of test conditions 

GM and Ford built similar hardware, claimed numerous 

problems with fillability and emissions control 

EPA followed-up with Ford and solved its problems; GM 

declined an EPA evaluation 

API also produced an onboard car, which had significant 

fill and driveability problems 

NHTSA staff indicated lack of a successful 

onboard-equipped vehicle was a key obstacle to resolving 

the safety issue - fill performance and driveability were 

key issues 

-26-
ONBOARD VEHICLE DEVELOPMENT 

• Vehicle selection 

• Design goals 

• Control system description 

• Test results 

-27-
P.31 

WHY A FORD TAURUS? 

• Same fuel system Ford modified - Ford claimed EPA design 

would not work on a vehicle 

• Production purge flow rate could handle onboard purge 

requirements 

• Production vehicle has excellent fill performance 

-28-
P.32 

DESIGN GOALS 

• Adapt simplified refueling hardware to a production vehicle 

• Meet proposed emission standard overall full range of 

possible fill rates (H O gal/min) 

• Retain or exceed stock car fill performance under even 

extreme conditions - high fill rates, high volatility, and 

high fuel temps 

• Minimize spitbacks at fill rates up to 15 gal/min 

• Avoid driveability/performance impacts 

-29-
CONTROL SYSTEM DESCRIPTION' 

Design is derived from EPA's "liquid seal" concept 

Production purge rate and schedule were retained 

Fuel system modifications: 

Added anti-spitback valve 

Modified fill inlet tube inside tank 

Removed external vapor vent line from tank/fill neck 

Added rollover/vent valve (.4" vent orifice) 

Upgraded existing tank vent valve with a larger 

production version 

Enlarged canister from 1,01 to 3.51 

Moved canister to rear of car from engine compartment 

Increased diameter and shortened vapor vent line 

Total system layout shown in Figure 7 

-30-
FORD FILLER PIPE 

5/8

 M I.D. HOSE 

VAPOR VENT VALVE 

CANISTER 

FORD FUEL TANK 

SPITBACK 

VALVE 

FIGURE 7 : ONBOARD REFUELING SYSTEM 

AS ON THE FORD VEHICLE 

-31 -
P.35 

TEST RESULTS 

Refueling emissions are significantly below the proposed 

standard (0,1 g/gal) from 3 to 10 gal/min 

No effects on exhaust emissions or driveability 

Laboratory fillability comparisons (show video): 

Performed at extreme conditions (15 RVP, 15 gal/min, 

and high fuel temp) 

No spitback from onboard car 

Fuel spray and spitback occurred on stock car 

Other late model cars were unfillable or had 

significant spitback 

Service station fillability comparisons (show video): 

Test conditions included high RVP winter fuels 

(14-15 RVP) and fill rates up to 12 gal/min 

Onboard and stock car had excellent fill performance 

Both vehicles substantially superior to other 

production vehicles 

-32-
. •*

 ;. 

SUMMARY 

• Control of refueling emissions is an important ozone 

control strategy 

• Onboard has many advantages over Stage II 

• EPA believes onboard can be implemented safely assuming 

sufficient leadtime 

-33-