[Code of Federal Regulations]
[Title 40, Volume 31]
[Revised as of July 1, 2007]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR1048.240]

[Page 568-569]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
 
PART 1048_CONTROL OF EMISSIONS FROM NEW, LARGE NONROAD 
SPARK-IGNITION ENGINES--Table of Contents
 
                  Subpart C_Certifying Engine Families
 
Sec.  1048.240  How do I demonstrate that my engine family complies with exhaust emission standards?

    (a) For purposes of certification, your engine family is considered 
in compliance with the applicable numerical emission standards in Sec.  
1048.101(a) and (b) if all emission-data engines representing that 
family have test results showing deteriorated emission levels at or 
below these standards.
    (b) Your engine family is deemed not to comply if any emission-data 
engine representing that family has test results showing a deteriorated 
emission level above an applicable emission standard from Sec.  1048.101 
for any pollutant.
    (c) To compare emission levels from the emission-data engine with 
the applicable emission standards, apply deterioration factors to the 
measured emission levels for each pollutant. Specify the deterioration 
factors based on emission measurements using four significant figures, 
consistent with good engineering judgment. For example, your 
deterioration factors must take into account any available data from in-
use testing with similar engines (see subpart E of this part). Small-
volume engine manufacturers may use assigned deterioration factors

[[Page 569]]

that we establish. Apply deterioration factors as follows:
    (1) Multiplicative deterioration factor. For engines that use 
aftertreatment technology, such as catalytic converters, use a 
multiplicative deterioration factor for exhaust emissions. A 
multiplicative deterioration factor is the ratio of exhaust emissions at 
the end of useful life to exhaust emissions at the low-hour test point. 
Adjust the official emission results for each tested engine at the 
selected test point by multiplying the measured emissions by the 
deterioration factor. If the factor is less than one, use one.
    (2) Additive deterioration factor. For engines that do not use 
aftertreatment technology, use an additive deterioration factor for 
exhaust emissions. An additive deterioration factor is the difference 
between exhaust emissions at the end of useful life and exhaust 
emissions at the low-hour test point. Adjust the official emission 
results for each tested engine at the selected test point by adding the 
factor to the measured emissions. If the factor is less than zero, use 
zero.
    (d) Collect emission data using measurements to one more decimal 
place than the applicable standard. Apply the deterioration factor to 
the official emission result, as described in paragraph (c) of this 
section, then round the adjusted figure to the same number of decimal 
places as the emission standard. Compare the rounded emission levels to 
the emission standard for each emission-data engine. In the case of HC + 
NOX standards, apply the deterioration factor to each 
pollutant and then add the results before rounding.

[70 FR 40474, July 13, 2005]