| 摘要 |
PURPOSE:To improve the accuracy in air-fuel ratio control by properly discriminating the error in air-fuel ratio judgement from the state of variation of the pump electric- current and the correction coefficient and controlling the air-fuel ratio in the direction close to an aimed air-fuel ratio, in an air-fuel ratio controller using an oxygen sensor. CONSTITUTION:An air-fuel ratio controller is equipped with an air-fuel ratio detecting means 31 which continuously calculates the air-fuel ratio from the concentration of the oxygen in exhaust gas and possesses the characteristic that the output varies in the same direction as the difference from the theoretical value increases, an aimed-value setting means 33 for air-fuel ratio, a differential-value calculating means 32 which calculates the deflection of the present air-fuel ratio from the aimed air-fuel ratio, and a correction-coefficient calculating means 35 which calculates the correction coefficient in the direction in which the present air-fuel ratio accords with the aimed air-fuel ratio on the basis of the output of the means 32 and reverses the direction of the variation of the correction coefficient. Further the controller is equipped with an air-fuel ratio control means 36, discriminating means 40 which discriminates that the present air-fuel ratio is rich or lean in comparison with the theoretical air-fuel ratio and compares the aimed air-fuel ratio with the theoretical air-fuel ratio, and a reversing-signal generating means 50 which outputs a reversing signal.
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