AIR FUEL RATIO DETECTING DEVICE

摘要

PURPOSE:To improve the detection accuracy of the air fuel ratio by measuring variation in vehicle speed from the start of a fuel cut to fuel cut recovery. CONSTITUTION:An air fuel ratio detecting means (A) detects the oxygen concentration in exhaust gas and a fuel cut detecting means (b) detects the fuel cut state of an engine. Then, a calibration quantity arithmetic means (d) computes the calibration quantity of the normal output of the means (a) based on the output of the means (a) when the pressure in an exhaust pipe is the atmospheric pressure. The calibration quantity from the means (d) is inputted to a correcting means (e) and corrected with the fuel cut state detection output of the means (b) and the vehicle speed detection output of a vehicle speed detecting means (c) according to the vehicle speed at the start of a fuel cut. Then an air fuel ratio arithmetic means (f) corrects the normal output of the means (a) based on the calibration value computed by the means (e) to calculate an air fuel ratio. The calibration of the sensor output becomes accurate and the accuracy of the air fuel ratio detection is improved.