Page 182 - Methods For Monitoring And Diagnosing The Efficiency Of Catalytic Converters A Patent - oriented Survey

164 Methods for Monitoring and Diagnosing the Efficiency of Catalytic Converters

In the method of the patent disclosure JP7259540 (1995) the engine aidfirel ratio is feedback-
controlled based on the signal of the upstream sensor in order to achieve a target aidfuel ratio.
The deterioration of the catalytic converter is assessed from the relation of the output signals
of the upstream and downstream oxygen sensors. During the time of deterioration detection,
an aidfuel ratio constant is altered in some extent, to prevent the occurrence of any mistakes of
the detection of the catalytic converter degadation due to variations of the wave form of the
upstream sensor.

Other methods presented by Mazda Motor Corp. should be found in JP4303754 (1992),
JP6280547 (1994), JP6280661 (1994), JP6280662 (1994) and JP6346723 (1994).