| 摘要 |
PURPOSE:To improve control precision of EGR efficiency, by a method wherein the opening of an EGR valve is controlled according to an output from an O2 sensor detecting O2 concentration in suction air mixed with EGR gas, and energization to a heater, heating the O2 sensor, is controlled according to a suction air amount. CONSTITUTION:An EGR valve 10 is located between pipes 11 and 12 through which an exhaust pipe 9 is communicated with a suction pipe 2, and is controlled by an electronic control circuit 14 according to an output from an O2 sensor 6 having a detector 12 for the number of revolutions of an engine, a suction air amount detector 4, and a heater 7 adapted to heat the sensor to an ordinary motion temperature. The O2 sensor 6, heated by the heater 7, is cooled by suction air to decrease temperature when a suction air amount is increased. In which case, in order to prevent decrease of temperature, control is effected so that a power fed to the heater 7 proportionally to an increase in a suction air amount is increased by a heater correcting means 15 to which an output signal from the suction air amount detector 4 is inputted. |
