APPARATUS FOR CONTROLLING HEATER OF AIR/FUEL RATIO SENSOR

摘要

PURPOSE:To prevent the overheat and cooling of a sensor, by performing the ON/OFF control of the supply of a current to a heater corresponding to the number of rotations of an engine and the load thereof. CONSTITUTION:A heater power source 4 is connected to a heater 2 and a current is supplied to a heater 2 from the power source 4 at a usual time to allow the heater 2 to perform heating action. The supply of a current to the heater 2 is stopped in a specific operation state by a current cutting-off means 5. The judgement of the operation state stopping the supply of a current to the heater 2 is performed by an operation region judge means 6 for judging the heater cutting-off region where the supply of a current to the heater 2 becomes unnecessary corresponding to the number of rotations of an engine and the load thereof. The heater cutting-off judge means 7 receiving the signal of said means 6 outputs a signal to the means 5 when the operation state continues for a predetermined time or more after came to the heater cutting-off region to stop the supply of a current to the heater 2. Therefore, the control of the heater can be performed with good accuracy.