||Development of an Improved Computer Simulation Vehicle Emissions During Cold Start and Warm-Up Operation.
||Sierra Research, Inc., Sacramento, CA.; Environmental Protection Agency, Ann Arbor, MI. Office of Mobile Sources.
Motor vehicle engines ;
Exhaust emissions ;
Cold starting ;
Computerized simulation ;
Correction factors ;
Exhaust gases ;
Fuel consumption ;
||Some EPA libraries have a fiche copy filed under the call number shown.
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.