| 摘要 |
PURPOSE:To prevent decrease of a purification factor of a ternary catalyzer, by deciding output from an O2 sensor on the basis of detection in a range of high load and revolution, outputting a signal and arranging a control gain of the signal lower than normal. CONSTITUTION:A signal from an O2 sensor 1 is decided by a decision circuit 3 in a control unit 2, and a control gain of fuel quantity is decided in a proportional integration signal generator circuit 4, converted into driving on-duty output of a fuel feed driving valve in an output circuit 5 and applied to an air- fuel ratio control unit 6 to control air-fuel ratio. At this time, a control gain changing circuit 10, decreasing the control gain, is connected to the circuit 4, and a prescribed high load and speed detector circuit 20, driving the circuit 10 at preset high load and revolution, is connected. In this way, even if speed of an engine and its load exceed a prescribed value, the control gain can be controlled to a fixed value, and sufficient performance of purifying exhaust can be obtained even at high speed running operation. |
