OXYGEN CONCENTRATION DETECTING DEVICE FOR INTERNAL COMBUSTION ENGINE

摘要

PURPOSE:To obtain a detection output which depends upon neither variation in exhaust temperature nor variation in exhaust air flow by detecting plural operation parameters of an internal combustion engine and correcting the output signal of an oxygen concentration sensor with a coefficient of correction based upon those operation parameters. CONSTITUTION:A suction pipe negative pressure sensor 31 and a TD pulser 34 for outputting engine rotating speed information are provided so as to detect plural operation parameters of the internal combustion engine. A CPU 309 corrects the output signal of the oxygen concentration sensor with the coefficient of correction based upon those operation parameters. The detection output which depends upon neither variation in exhaust temperature and variation in exhaust flow rate is therefore obtained without performing complicate temperature control by a heater current supply circuit 308 nor making the structure of the sensor body complex. Thus, variance in detected air-fuel ratio due to exhaust temperature dependency and exhaust flow rate dependency is eliminated, so the accuracy of air-fuel ratio control is improved.