To provide an air-fuel ratio compensating control in which emission is improved by providing compensated auxiliary air fuel ratio with initial value.
This control unit is provided with a catalyst (a) disposed in the exhaust path of an internal combustion engine, an upstream side oxigen sensor (b) disposed on the exhaust path so as to locate on the upstream side of the catalyst (a), a downstream side oxigen sensor (c) disposed on the exhaust path so as to locate on the downstream side of the catalyst (a), a main air fuel ratio compensating means (d) for computing compensated main air fuel ratio value according to the output V1 of the upstream side oxigen sensor (b), an auxiliary air fuel ratio compensating means (e) for computing compensated auxiliary air fuel ratio value according to the output V2 of the downstream side oxigen sensor (c), an air-fuel ratio control means (f) for controlling the air fuel ratio of the internal combustion engine according to the compemsated main air fuel ratio value and the compensated auxiliary air fuel ratio value, a catalyst deterioration detecting mains (g) for detecting the degree of deterioration of the catalyst, a memorizing means (h) for memorizing the detected degree of deterioration, an initial value computing means (i) for computing the initial value of the compensated auxiliary air fuel ratio value. Thereby, this initial value is utilized to control the air fuel ratio being based on the compensated auxiliary air fuel ratio value after the internal combustion engine is started.
SATO KENICHI
TOSHIRO TAKAYUKI
YAMADA SHUNJI
Next Patent: AIR FUEL RATIO FEEDBACK CONTROLLER FOR ENGINE