Compensating control manner null of the 2 sensor under O in air-fuel ratio controlling of on vehicle

摘要

PURPOSE:To perform the proper air-fuel ratio control by exercising the feedback so that an area ratio of the output of an O2 sensor at the upper and lower sides of a slice level of the O2 sensor is kept at a fixed value and reflecting the responding time of the sensor on the area ratio. CONSTITUTION:An electronic controller is composed of a CPU1, a ROM2, a RAM3, an input port 4, an output port 5, a data bus 6, etc. and the O2 sensor 7, a water temperature sensor 8, a throttle sensor 9 and a sensor 10 of the suction pipe negative pressure or the like are connected with the input port 4 via an A/D converter 11 and an REF signal of the number of revolutions of an engine or the like and a signal from a crank angle sensor are taken in as the digital signals. The O2 sensor indicates a fluctuation wave near to a rectangular wave when the air-fuel ratio is shaken with the stoichiometry as a center, but actually, it becomes a broken waveform. Then, the area ratio of the output of the O2 sensor at the upper and lower sides of the slice level is kept at the fixed value and the area ratio is changed corresponding to the deterioration of the O2 sensor with the lapse of time and the slice level is changed to compensate the deterioration of the O2 sensor.