Patent ID: 7007458
Filing Date: 2006-03-07
Classification: F01N,F02D,Y02A,Y02T

Abstract:
1. A computer-controlled emission diagnostic system for an engine exhaust system of a vehicle, comprising: a first emission control device coupled to an exhaust of the engine; a second emission control device coupled downstream of said first emission control device; a first exhaust gas sensor coupled upstream of said first emission control device; a second exhaust gas sensor coupled in or downstream of said second emission control device; a computer storage medium having a computer program encoded therein for monitoring the engine exhaust system comprising: code for reading a fist signal from said first exhaust gas sensor, code for reading a second signal from said second exhaust gas sensor; code for indicating an interval in which said first emission control device is operating with an oxygen storage capacity above a preselected percentage based on an estimated catalyst temperature of said first emission control device and said second emission control device is operating with an oxygen storage capacity below a predetermined percentage based on an estimated catalyst temperature of said second emission control device; and code for determining performance of said first emission control device based at least on said first and second signals during said indicated interval.