Apparatus for controlling idling speed of motor vehicle engine

Abstract

Disclosed is an apparatus for controlling at the time of idling the rotational speed of an engine having an injector for injecting fuel in proportion to the width of an input pulse. The control apparatus includes: a rotational speed sensor for cyclically detecting the rotational speed of the engine; an airflow meter for cyclically detecting the quantity of air being sucked into the engine; an idle switch for detecting the complete closing of a throttle valve; a judging means for judging that the engine is in the idling condition on the basis of the output of the idle switch and the output of the rotational speed sensor; and an operating means for cyclically outputting the injector a fuel injection pulse having a pulse width obtained by the following expression on the basis of the output of the rotational speed sensor and the output of the airflow meter when the judging means has judged that the engine is in the idling condition. Tp.sub.1 =k(Qa.sub.1 /N.sub.1).multidot..alpha.+Tp.sub.0 .multidot.(1-.alpha.) Tp.sub.1 : width of a pulse to be output at the present time Tp.sub.0 : width of a pulse which was output the previous time Qa.sub.1 : presently detected value for the quantity of air being sucked in N.sub.1 : presently detected value for the rotational speed of the engine .alpha.: filter constant 0<.alpha.<1 k: constant

Dependencies are inferred from the claim text.