{"data":{"id":"us/40-cfr-1039.510","jurisdiction":"us","citation":"40 CFR 1039.510","heading":"Which duty cycles do I use for transient testing?","body":"(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):\n(1) For variable-speed engines, use the transient duty cycle described in appendix VI of this part.\n(2) [Reserved]\n(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:","path":["Title 40—Protection of Environment","CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY","SUBCHAPTER U—AIR POLLUTION CONTROLS","PART 1039—CONTROL OF EMISSIONS FROM NEW AND IN-USE NONROAD COMPRESSION-IGNITION ENGINES","Subpart F—Test Procedures"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-40.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:26:04Z","sha256":"77757bad8a332f08f2911afec0a26e69e95a5738eda30167ec3cceb713887d96","source_id":"us-cfr","stale":true,"prev":"us/40-cfr-1039.505","next":"us/40-cfr-1039.515"},"notice":"GroundRules: Original legal text. Not legal advice."}