[Code of Federal Regulations]
[Title 40, Volume 30]
[Revised as of July 1, 2004]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR1051.235]

[Page 616-617]
 
                   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. 1051.235  What emission testing must I perform for my application 
for a certificate of conformity?

    This section describes the emission testing you must perform to show 
compliance with the emission standards in subpart B of this part during 
certification.

[[Page 617]]

    (a) Test your emission-data vehicles using the procedures and 
equipment specified in subpart F of this part. Where specifically 
required or allowed, test the engine instead of the vehicle. For 
evaporative emissions, test the fuel system components separate from the 
vehicle.
    (b) Select from each engine family a test vehicle or engine, and a 
fuel system for each fuel type with a configuration that is most likely 
to exceed the emission standards, using good engineering judgment, 
consider the emission levels of all exhaust constituents over the full 
useful life of the vehicle.
    (c) You may use previously generated emission data in the following 
cases:
    (1) You may submit emission data for equivalent engine families from 
previous years instead of doing new tests, but only if the data show 
that the test vehicle or engine would meet all the requirements for the 
latest vehicle or engine models. We may require you to do new emission 
testing if we believe the latest vehicle or engine models could be 
substantially different from the previously tested vehicle or engine.
    (2) You may submit emission data for equivalent engine families 
performed to show compliance with other standards (such as California 
standards) instead of doing new tests, but only if the data show that 
the test vehicle or engine would meet all of this part's requirements.
    (3) You may submit evaporative emission data measured by a fuel 
system supplier. We may require you to verify that the testing was 
conducted in accordance with the applicable regulations.
    (d) We may choose to measure emissions from any of your test 
vehicles or engines (or other vehicles or engines in the engine family).
    (1) If we do this, you must provide the test vehicle or engine at 
the location we select. We may decide to do the testing at your plant or 
any other facility. If we choose to do the testing at your plant, you 
must schedule it as soon as possible and make available the instruments 
and equipment we need.
    (2) If we measure emissions on one of your test vehicles or engines, 
the results of that testing become the official data for the vehicle or 
engine. Unless we later invalidate this data, we may decide not to 
consider your data in determining if your engine family meets the 
emission standards.
    (3) Before we test one of your vehicles or engines, we may set its 
adjustable parameters to any point within the physically adjustable 
ranges (see Sec. 1051.115(c)). We may also adjust the air-fuel ratio 
within the adjustable range specified in Sec. 1051.115(d).
    (4) Calibrate the test vehicle or engine within normal production 
tolerances for anything not covered by Sec. 1051.115(c) and (d) of this 
section.
    (e) If you are a small-volume manufacturer, you may certify by 
design on the basis of preexisting exhaust emission data for similar 
technologies and other relevant information, and in accordance with good 
engineering judgment. In those cases, you are not required to test your 
vehicles.
    This is called ``design-certification'' or ``certifying by design.'' 
To certify by design, you must show that the technology used on your 
engines is sufficiently similar to the previously tested technology that 
a person reasonably familiar with emission-control technology would 
believe that your engines will comply with the emission standards.
    (f) For fuel tanks that are certified based on permeability 
treatments for plastic fuel tanks, you do not need to test each engine 
family. However, you must use good engineering judgment to determine 
permeation rates for the tanks. This requires that more than one fuel 
tank be tested for each set of treatment conditions. You may not use 
test data from a given tank for any other tanks that have thinner walls. 
You may, however, use test data from a given tank for other tanks that 
have thicker walls. This applies to both low-hour (i.e., baseline 
testing) and durability testing. Note that Sec. 1051.245 allows you to 
use design-based certification instead of generating new emission data.

[[Page 618]]