Patent ID: 6804951
Filing Date: 2004-10-19
Classification: F01N,F02D,Y02T

Abstract:
A method for determining the effectiveness of a catalyst having both first, relatively high oxidizable material provided to remove emissions from the exhaust of an internal combustion engine and a second, relatively low oxidizable material provided to remove emissions from such exhaust, such method comprising:measuring an upstream time history of a signal produced by an exhaust gas oxygen sensor upstream of the converter and a time history of an exhaust gas oxygen sensor disposed downstream of the converter, such time histories having first transitions when the time history varies between a lean air-fuel ratio signal level and a rich air-fuel ratio signal level and having second transitions when the time history varies between a rich air-fuel ratio signal level and a lean air-fuel ratio signal level; determining a time delay between only the first transitions in the upstream time history and the downstream time history; comparing the determined time delay with a reference time delay to determine the efficiency of the converter; determining the effectiveness of the converter from such comparison.