Patent ID: 7900439
Filing Date: 2011-03-08
Classification: F01N,Y02T

Abstract:
1. A diagnostic system for an exhaust system including a catalyst and a post-catalyst oxygen sensor, comprising: a first diagnostic module that monitors the post-catalyst oxygen sensor during a first period, that estimates a total integrated area based on a signal from the post-catalyst oxygen sensor, that compares the total integrated area to a threshold integrated area, and that determines a pass/fail status of the post-catalyst oxygen sensor based on the comparison, wherein the first diagnostic module generates a pass status signal when the total integrated area is less than the threshold integrated area and generates a fail status signal when the total integrated area is greater than the threshold integrated area; and a second diagnostic module that monitors the catalyst during a second period, and that determines a pass/fail status of the catalyst based on the monitoring during the second period, wherein the first period includes the second period, and wherein the second period starts after the first period starts.