Air-fuel ratio control method for internal combustion engine


PURPOSE: To prevent an air-fuel ratio characteristic from changing in accordance with an increase of heater resistance due to its aging, by correcting a feedback- controlled fuel supply quantity to be increased corresponding to a decrease of heating amount in an oxygen sensor with a heater. CONSTITUTION: A heater 25a, which is inserted into the internal part of an oxygen sensor 25, is connected with a battery 29a through a starter switch 29. The other end of the heater 25a is connected with a potentiometer 29b, and the potentiometer 29b, having in its inside a resistor 29c with a resistance value sufficiently smaller than that of the heater 25a, detects a potential difference, generated by said resistor 29c, by a main unit to be output to an electronic control unit 30. The electronic control unit, if it decides the resistance value of the heater 25a to be increased and its heating amount to be decreased, corrects a fuel supply amount by a feedback control on the basis of a detection value of the oxygen sensor 25 to be increased. COPYRIGHT: (C)1987,JPO&Japio




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Cited By (2)

    Publication numberPublication dateAssigneeTitle
    JP-H0577841-B2October 27, 1993Hitachi Ltd, Hitachi Eng Co Ltd
    JP-S6480706-AMarch 27, 1989Hitachi Ltd, Hitachi Eng Co LtdTurbine control device