Title:
DETERIORATION DETECTING DEVICE FOR CATALYST
Document Type and Number:
Japanese Patent JPH03249320
Kind Code:
A
Abstract:
PURPOSE:To detect deterioration of a catalyst with good accuracy by calculating a correlation coefficient on the basis of output values of first and second oxygen sensors arranged respectively on upper and lower stream from a catalyst. CONSTITUTION:A catalyst 15 for cleaning exhaust gas is arranged in the exhaust system of an engine 1, while oxygen sensors 16, 18 are respectively provided on upper and lower stream from the catalyst 15 so as to detect whether an air fuel ratio is rich or lean condition in comparison with a theoretical air fuel ratio. in an ECU 20, correlation coefficients of respective output values are calculated on the basis of the output values of the oxygen sensors 16, 16, so that deterioration of the catalyst 15 is detected in response to the correlation coefficients. In this state, the characteristics of the correlation coefficient and the cleaning rate of the catalyst 15, include enough resolution capacity even in a low cleaning ratio. It is thus possible to detect deterioration of the catalyst with good accuracy.
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Inventors:
NAKABAYASHI KATSUHIKO
NAKANE HIROAKI
NAKANE HIROAKI
Application Number:
JP5016090A
Publication Date:
November 07, 1991
Filing Date:
February 28, 1990
Export Citation:
Assignee:
NIPPON DENSO CO
International Classes:
F02B77/08; F01N3/20; F01N11/00; F02D45/00; (IPC1-7): F01N3/20; F02B77/08; F02D45/00
Attorney, Agent or Firm:
Takashi Okabe (1 outside)
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