Page 120 - Methods For Monitoring And Diagnosing The Efficiency Of Catalytic Converters A Patent - oriented Survey
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102 Methods for Monitoring and Diagnosing the Efficiency of Catalytic Converters
where a = ratio of the amount of oxygen contained in air
6) determining a degree of deterioration of the catalyst on the basis of said calculated amount
ofoxygen stored in the catalyst.
The method of JP8210126 (1996) describes a catalytic converter deterioration discrimination
device, which inhibits the deterioration judgment when a value of the constant used for the
feedback control of the engine airhel ratio reaches a predetermined threshold. The feedback
control is based on the output signal of the upstream oxygen sensor. The method prevents
judgment error due to a leak in the exhaust pipe.
correction I
Fig. 5 1 (from EP0690213)
