Air-fuel ratio control device of internal combustion engine

Abstract

Abstract PURPOSE:To enhance the purification performance of three way catalyst by varying the central value of a self-excited control waveform having the specified cycle and amplitude according to the average value of the output of the O2 sensor provided downstream from the catalyst and controlling an air-fuel ratio according to the self-excited control waveform. CONSTITUTION:The value detected by an air flow meter 3, crank angle sensors 5 and 6, idle switch 16, the O2 sensor 14 provided in the lower course of a three way catalyst flow 12 and so on are input in a control circuit 10 to operate and control the opening time of a fuel injection valve 7. The control circuit 10 operates the average value of the output of an O2 sensor 14 on the down- stream side and calculates the central value of a self-excited control waveform so that the central value is made small when average value is large. And when self-excited conditions are settled except for fuel increase value for warming up during the start-up of an engine and fuel cut during power loading, the skip control of an air-fuel ratio correction factor is performed according to the self-excited control waveform having the specified cycle and amplitude and on the center of the calculated central value.

Inventors

• 👤 Yutaka Sawada
• 👤 Mitsuhiro Nada
• 👤 Ryuichi Deguchi
• 👤 Toru Hanabusa
• 👤 Hiroki Matsuoka

Bibliographic Details