[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: 40CFR1048.510]

[Page 582]
 
                   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 F_Test Procedures
 
Sec.  1048.510  Which duty cycles do I use for transient testing?

    (a) Starting with the 2007 model year, measure emissions by testing 
the engine on a dynamometer with one of the following transient duty 
cycles to determine whether it meets the transient emission standards in 
Sec.  1048.101(a):
    (1) For constant-speed engines and severe-duty engines, use the 
transient duty-cycle described in Appendix I of this part.
    (2) For all other engines, use the transient duty cycle described in 
Appendix II of this part.
    (b) If we test an engine to confirm that it meets the duty-cycle 
emission standards, we will use the transient duty cycle that applies 
for that engine family.
    (c) Warm up the test engine as follows:
    (1) Operate the engine for the first 180 seconds of the appropriate 
duty cycle from Appendix I or Appendix II of this part, then allow it to 
idle without load for 30 seconds. At the end of the 30-second idling 
period, start measuring emissions as the engine operates over the 
prescribed duty cycle. For severe-duty engines, this engine warm-up 
procedure may include up to 15 minutes of operation over the appropriate 
duty cycle.
    (2) If the engine was already operating before a test, use good 
engineering judgment to let the engine cool down enough so measured 
emissions during the next test will accurately represent those from an 
engine starting at room temperature. For example, if an engine starting 
at room temperature warms up enough in three minutes to start closed-
loop operation and achieve full catalyst activity, then minimal engine 
cooling is necessary before starting the next test.
    (3) You are not required to measure emissions while the engine is 
warming up. However, you must design your emission-control system to 
start working as soon as possible after engine starting. In your 
application for certification, describe how your engine meets this 
objective (see Sec.  1048.205(b)).

[67 FR 68347, Nov. 8, 2002, as amended at 70 FR 40478, July 13, 2005]