AIR-FUEL RATIO CONTROL DEVICE FOR ENGINE

摘要

PROBLEM TO BE SOLVED: To provide an air-fuel ratio control device for an engine corresponding to inactive time of an air-fuel ratio sensor. SOLUTION: In this air-fuel ratio control device for an engine for calculating a basic injection pulse width Duty-FF according to an operating condition and performing a feedback control for gaseous fuel quantity injected to an upstream side from a throttle valve of an intake passage according to an air-fuel ratioλof air-fuel mixture detected by the air-fuel ratio sensor, the device is provided with a compensation fuel injection quantity calculation means 48 for calculating a compensation injection pulse width Duty-wt-std according to an engine cooling water temperature Tw and engine speed Ne and an output means 60 for selecting a larger value of the basic injection pulse width Duty-FF and the compensation injection pulse width Duty-wt-std and making the value as an output Duty-out to a fuel injection valve driving means 50 at inactive time or failing time of the air-fuel ratio sensor.