PURPOSE: To prevent the fluctuation of the igniton timing under an extremely low revolution of the engine by a method wherein an ignitor is put ON at first predetermined crank angle before an upper dead point and the ignitor is put OFF at second predetermined crank angle before the upper dead point under the low revolution of the engine.
CONSTITUTION: When the revolving number of the engine detected by an engine revolution number sensor 32, is higher than a predetermined revolution number, a fuel injection time and the timing of ON, OFF of the ignitor are controlled based on the revolution number and the load of the engine. When the revolution number of the engine is up to the predetermined revolution number, the fuel injection time is determined in accordance with only a cooling water temperature sensed by a sensor 24 showing the operating condition of the engine and the ignitor 28 is put ON at the first predetermined crank angle of 60°, for example, before the upper dead point of the engine while the ignitor 28 is put OFF at the second predetermined crank angle of 30°, for example, which is nearer to the upper dead point, to ignite the engine. According to this method, the ignition may be effected surely at the predetermined crank angle and stable operation may be effected.
ANZAI KATSUSHI
SUEMATSU TOSHIO
ITOU YOSHIYASU
