Record Display for the EPA National Library Catalog


Main Title Development of an Improved Computer Simulation Vehicle Emissions During Cold Start and Warm-Up Operation.
CORP Author Sierra Research, Inc., Sacramento, CA.; Environmental Protection Agency, Ann Arbor, MI. Office of Mobile Sources.
Year Published 1991
Report Number SR91-09-02
Stock Number PB2014-107394
Additional Subjects Motor vehicle engines ; Exhaust emissions ; Cold starting ; Algorithms ; Catalysts ; Combustion ; Computerized simulation ; Correction factors ; Exhaust gases ; Fuel consumption ; Warm-up
Library Call Number Additional Info Location Last
NTIS  PB2014-107394 Some EPA libraries have a fiche copy filed under the call number shown. 07/26/2022
Collation 24p
Based on an analysis of model emissions data from vehicles tested by EPA, an algorithm has been developed to simulate cold start and warm-up operation using a vehicle emissions simulation model called VEHSIME. During the first 450 seconds of operation following a cold start, the algorithm applies correction factors to the emission rates in 'map' of emission rates over the full speed and load range of a warmed-up engines. The correction factor increases 'engine-out' HC and CO emissions in proportion to the number of seconds left in the warm-up period. The algorithm also applies a catalyst efficiency factor to the map of engine-out emissions as soon as the fuel consumption since start up reaches the cumulative fuel consumption associated with the catalyst reaching 'light-off' temperature on the LA4 cycle.