Patent ID: 6360530
Filing Date: 2002-03-26
Classification: F01N,F02D

Abstract:
A method for controlling the operation of an internal combustion engine in a motor vehicle, wherein the engine generates exhaust gas including an exhaust gas constituent, and wherein exhaust gas is directed through an emissions control device before being exhausted to the atmosphere, the device storing a quantity of the exhaust gas constituent when the exhaust gas directed through the device is lean of stoichiometry and releasing a previously-stored amount of the exhaust gas constituent when the exhaust gas directed through the device is rich of stoichiometry, the method comprising:determining a first measure representative of a total amount of the first exhaust gas constituent exhausted to the atmosphere during a first engine operating period; determining a second measure representing a distance traveled by the vehicle during the first engine operating period; and calculating a third measure based on the first measure and the second measure; comparing the third measure to a predetermined threshold, the predetermined threshold being periodically adjusted based upon an indication of vehicle activity; and discontinuing lean engine operation when the third measure exceeds the predetermined threshold.