[Code of Federal Regulations]

[Title 40, Volume 31]

[Revised as of July 1, 2006]

From the U.S. Government Printing Office via GPO Access

[CITE: 40CFR1051.243]



[Page 636-637]

 

                   TITLE 40--PROTECTION OF ENVIRONMENT

 

         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)

 

PART 1051_CONTROL OF EMISSIONS FROM RECREATIONAL ENGINES AND VEHICLES

--Table of Contents

 

                  Subpart C_Certifying Engine Families

 

Sec.  1051.243  How do I determine deterioration factors from exhaust 

durability testing?



    Establish deterioration factors to determine whether your engines 

will meet emission standards for each pollutant throughout the useful 

life, as described in subpart B of this part and Sec.  1051.240. This 

section describes how to determine deterioration factors, either with 

pre-existing test data or with new emission measurements.

    (a) You may ask us to approve deterioration factors for an engine 

family based on emission measurements from similar vehicles or engines 

if you have already given us these data for certifying other vehicles in 

the same or earlier model years. Use good engineering judgment to decide 

whether the two vehicles or engines are similar. We will approve your 

request if you show us that the emission measurements from other 

vehicles or engines reasonably represent in-use deterioration for the 

engine family for which you have not yet determined deterioration 

factors.

    (b) If you are unable to determine deterioration factors for an 

engine family under paragraph (a) of this section, select vehicles, 

engines, subsystems, or components for testing. Determine deterioration 

factors based on service accumulation and related testing to represent 

the deterioration expected from in-use vehicles over the full useful 

life, as follows:

    (1) You must measure emissions from the emission-data vehicle at a 

low-hour test point and the end of the useful life. You may also test at 

evenly spaced intermediate points.

    (2) Operate the vehicle or engine over a representative duty cycle 

for a period at least as long as the useful life (in hours or 

kilometers). You may operate the vehicle or engine continuously.

    (3) You may perform maintenance on emission-data vehicles as 

described in Sec.  1051.125 and 40 CFR part 1065, subpart E.

    (4) If you measure emissions at only two points to calculate your 

deterioration factor, base your calculations on a linear relationship 

connecting these two data points for each pollutant. If you measure 

emissions at three or more points, use a linear least-squares



[[Page 637]]



fit of your test data for each pollutant to calculate your deterioration 

factor.

    (5) Use good engineering judgment for all aspects of the effort to 

establish deterioration factors under this paragraph (b).

    (6) You may to use other testing methods to determine deterioration 

factors, consistent with good engineering judgment.

    (c) Include the following information in your application for 

certification:

    (1) If you use test data from a different engine family, explain why 

this is appropriate and include all the emission measurements on which 

you base the deterioration factor.

    (2) If you do testing to determine deterioration factors, describe 

the form and extent of service accumulation, including a rationale for 

selecting the service-accumulation period and the method you use to 

accumulate hours.



[70 FR 40496, July 13, 2005]