Patent ID: 6487849
Filing Date: 2002-12-03
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 a first 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 first constituent when the exhaust gas directed through the device is lean of stoichiometry, the method comprising:determining a first measure representing a performance impact of operating the engine at a first operating condition characterized by combustion of an air-fuel mixture that is lean of a near-stoichiometric air-fuel mixture, wherein the measure is based on at least one engine or vehicle operating parameter; determining a second measure representing an efficiency of the device in removing the first constituent from the exhaust gas; and prohibiting operation of the engine at the first operating condition based on the first measure and the second measure, wherein the performance impact is a relative efficiency calculated with reference to engine operation at the near-stoichiometric operating condition.