Patent ID: 6374597
Filing Date: 2002-04-23
Classification: F01N,F02D,Y02T

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 that the engine is operating in a first engine operating region immediately following a rich engine operating condition, the rich engine operating condition having been sufficient to release substantially all of the previously-stored amount of the exhaust gas constituent from the device, the first engine operating region being characterized by an exhaust gas space-velocity measure below a predetermined threshold; and when operating in the first engine operating region, detecting a first air-fuel ratio of the exhaust gas upstream of the device, detecting a second air-fuel ratio of the exhaust gas downstream of the device, and determining a measure representative of an ability of the device when the first air-fuel ratio is lean of stoichiometry and the second air-fuel ratio is not lean of stoichiometry.