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OAR Box 1171 

Prepped by Ollie Stewart 

Document Number: 

11) VII-A-1 

Docket Number: 

A-87-11 

Printed 4/30/2008 7:18:32 AM Sheet 11 of 47 
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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

ANN ARBOR. MICHIGAN 48105 

"5)r 

JU 

B i E 0 W S Q 

JUN - I I994 

EPA AIR L\.CKET 

OFFICE OF 

AIR AND RADIATION 

Madeline Burns 

Nissan North America 

750 17th Street, NW 

Suite 92 

Washincrto'n, DC 20006 

Dear Ms. Burns: 

This is in response to your fax of April 11, 19M which 

contained a series of questions regarding implementation of the 

light-duty vehicle and light-duty truck ORVR requirements. I will 

respond to your questions in the order they were presented. 

1 The ORVR rule extends the existing provisions for the OBD 

' systems to ORVR equipment. The current OBD requirements apply 

to th~ ' 98MY, however, manufacturers are allowed to use the CA 

OBD H system to satisfy the federal requirements for the 

'98MY. Conformity with the Federal OBD is required with .he 

'99MY. 

Is it still acceptable for a manufacturer to use a CA OBDII 

sjstem on ' 98MY vehicles if the system does not have the 

JapaSity to monitor ORVR? Does the OBD exemption supersede 

the ORVR monitoring requirements? 

ReSP °As e stat-d in the preamble to the ORVR final rule, the OBD 

system 'must monitor ^performance of ORVR V*TM'^^TM 1 TM 

whether the vehicle uses California OBD II or Federal OBD. EPA 

iZTcts tS t most (if not all) ~»^TM » -" i ^11^*0 ^ 

ORVR/evaporative control system designs. Both the California uuu 

?f*tnd federal OBD systems will monitor the evaporative control 

svstem purge/pressure functions. Thus, as a practical matter it is 

Z7»f!l*Ters 2j B u . : cilifo»i. OBD II*1£B , but EPA will 

conduct a separate evaluation to determine if it 

requirements. 
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2. Compliance 

A) How should the phase-in percentages be calculated? In 

the current Evaporative and Cold CO rules, a manufacturer 

is supposed to use the sales volume for the calculation 

but if we can demonstrate that the sales volume is 

similar to the production volume, we can use the 

production volume to calculate compliance. 

Do the same conditions apply to the ORVR percentage 

calculation? 

Response 

For ORVR, the Clean Air Act is not specific to this point. 

Thus, EPA willipermit manufacturers to use either sales volumes or 

production volumes in determining compliance. 

B. Under the Evap and Cold CO rules, if a manufacturer does not 

meet the percentage phase-in requirements and EPA believes 

that the manufacturer is making a good faith effort to meet 

the percentage phase-in requirements, EPA will not seek 

enforcement action. The rules allow a 10% margin of error for 

phase-in. 

Do the same rules apply for ORVR? Under what conditions would 

EPA seek to bring an enforcement action? 

Response 

For ORVR, the Clean Air Act is specific as to the phase-in 

percentages. The applicable percentages are 40 percent in the 

first model year in which the standards are applicable, 80 percent 

in the second model year and 100 percent after the second model 

year. There is no margin for error allowed by the statutory 

language nor is there a standard provision for margin of error. 

Nissan should not rely on enforcement discretion to cover any 

shortfalls below these percentages. 

By the way, discussions with personnel responsible for the 

evaporative emission rulemaking indicated the same policy was in 

effect for that regulations. 

However, the preamble of the Cold Temperature CO Regulations 

(July 17, 1992, p. 31890) does allow for unusual circumstances 

beyond a manufacturers control (e.g., a fire in a production plant) 

which may prevent the manufacturer from achieving its required 

phase-in percentages. In such cases, if the shortfall in actual 

sales is less than or equal to 10 percent of the phase-in 

percentages and there is no indication that shortfall resulted from 

bad faith on the part of the manufacturer, EPA may then exercise 

its enforcement discretion. Clearly, EPA's intent is to allow for 

circumstances beyond a manufacturers control rather than providing 

a 10 percent tolerance to be used as a production target. 
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3. Seal Test 

In the preamble, EPA mentions that the intention of the seal 

test is to verify the integrity of the fillpipe seals and 

vapor lines. Nissan believes that this can be verified 

through a full refueling test. In other words, if there are 

problems with the fillpipe seals and vapor lines, the vehicle 

will not comply with the standard. 

Is there another intention for the seal test other than the 

one mentioned in the preamble? 

Response 

As discussed in the preamble, the seal test is designed as a 

test to verify the integrity of the fillpipe seal, vapor lines, 

valves and other fittings in the fuel vapor control system before 

the canisters. It will also serve as a useful screening test for 

in-use vehicle performance. By routing the fuel vapor line outside 

the SHED, one can simulate a 100 percent effective canister. If a 

vehicle fails the refueling emission standard in a SHED test under 

these conditions, it would be expected that the vehicle would also 

fail the standard in a full refueling emission control system 

configuration in a SHED test. 

4. DF Calculation 

How should a manufacturer calculate a separate DF for the 

evaporative/refueling system in the case of an integrated 

system? Our educated guess is as follows: 

A) Manufacturer conducts evaporative emission tests and 

~" refueling emission tests at each test point of durability 

testing. 

B) Manufacturer adds evaporative emission test data to 

refueling emission test data to get "total data." 

C) Manufacturer plots total available data and calculated 

DF. 

Can you confirm our understanding? 

Response 

I believe your understanding is incorrect. There are separate 

evaporative, running loss and refueling emission standards, and 

compliance with each standard must be demonstrated. Thus, it is 

expected that evaporative, running loss, and refueling emission DFs 

will be determined separately in accordance with applicable 

regulations in 86.098-26,. and the DF for each requirement will be 

applied to the appropriate emission results for the data vehicles 

to determine compliance with the emission standard