StacksVerified U.S. regulatory reference

40 CFR §1039.510

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
  1. (a)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 § 1039.101(a):
    1. (1)For variable-speed engines, use the transient duty cycle described in appendix VI of this part.
    2. (2)[Reserved]
  2. (b)The transient test sequence consists of an initial run through the transient duty cycle from a cold start, 20 minutes with no engine operation, then a final run through the same transient duty cycle. Calculate the official transient emission result from the following equation: