WARMING UP DETECTOR FOR AIR TO FUEL RATIO CONTROLLER OF INTERNAL COMBUSTION ENGINE

摘要

PURPOSE:To enable accurate air to fuel ratio feedback control by starting the air to fuel ratio control when the time at which an O2 sensor is activated and the time at which the engine operation status requires the supply of the mixture of a theoretical air to fuel ratio. CONSTITUTION:A constant current circuit 214 which supplies constant current to an O2 sensor 28 is inserted between the O2 sensor 28 and a power supply 53 and the output of the O2 sensor 28 is input to an internal resistance decision circuit 215. A signal delay timer circuit 216 is connected to the output side of the internal resistance decision circuit 215 and the output side of the same circuit 216 is connected to one input terminal of an AND circuit 217. The output of an engine temperature decision circuit 219 which inputs the output signal of a thermistor 29 is input to the other input terminal of the AND circuit 217. Besides, when output is input to both the circuits 217 and 219, a signal S2 for starting the feedback control is output from the AND circuit 217. The output of the said decision circuits 215 and 219 is also input to a fault decision circuit 220.