Control apparatus, for internal combustion engine, for improving

Abstract

An engine control apparatus is disclosed, in which the combustion instability is improved regardless of the type of fuel supplied to the engine so that the idle state immediately after an engine start is stabilized for improving the fuel consumption rate, preventing the deterioration of emission and thereby improving the durability of catalysts. A counter counts the time elapsed from an engine start. A sensor detects the engine speed. A control circuit controls the timing of fuel injection into the engine. The intake-synchronous injection is carried out during a first predetermined time immediately after a cold engine start. The intake-asynchronous injection is carried out after the lapse of the first predetermined time. During the intake-asynchronous injection, the engine speed is monitored to determine whether it is reduced below a reference engine speed until the lapse of a second predetermined time. In the case where the engine speed is reduced below the reference engine speed, the intake-synchronous injection is temporarily carried out and the engine speed is increased for stabilizing the idle state. The control apparatus can store the idling characteristic for cold engine start for each type of fuel supplied so that temporary intake-synchronous injection may be carried out only for the heavy fuel.