Patent ID: 6742330
Filing Date: 2004-06-01
Classification: B01D,F01N,Y02A,Y02T

Abstract:
In a method for controlling emissions in the exhaust gases of a vehicular internal combustion engine passing through a catalyst by regulating the engine and/or an external reactant metered to the exhaust gases in response to a number of sensed and/or calculated variables, including the functional temperature of the catalyst, the improvement comprising the steps of:a) sensing the ambient temperature b) filtering the functional catalyst temperature determined by the emission control method at the time the engine is shut off by a first order filter using a cool down time constant established as a function of time elapsed from engine shut down at any given catalyst temperature at shut down or as a function of the difference in temperature between ambient temperature and catalyst shut down temperature to establish a functional cool down temperature of the catalyst and c) using the functional cool down temperature as the functional catalyst temperature in the emission control method upon restart of the engine.