| 摘要 |
PURPOSE:To start feedback control of an air-fuel ratio without delay by providing an O2 sensor with a heater having the heater to be turned on and off according to the parameter quantity of the operating state of an engine and turning on the heater for the prescribed time after an ignition is off. CONSTITUTION:A catalyst converter 8b contg. a ternary catalyst for simultaneous cleaning up of three harmful components HC, CO and NOx in an exhaust gas is provided to the exhaust system on the down stream of an exhaust manifold 8a. The O2 sensor 9 with the heater which generates the electric signal corresponding to the concn. of the oxygen component in the exhaust gas is provided to an exhaust pipe 8c on the down stream side of the exhaust manifold 8a and on the upper stream side of the converter 8b. The output of the O2 sensor 9 is supplied via a signal processing circuit 111 of a control circuit 10 to an A/D converter 10. The heater of the O2 sensor 9 is kept energized by the control circuit 10 until the O2 sensor attains an active temp. in the stage such as right after the start of the engine when the heating of the O2 sensor is required. The heater is turned on for the prescribed time after the ignition key is off. |
