PURPOSE: To smooth the combustion of an engine, by controlling the injection timing of fuel in accordance with a temperature of the Diesel engine.

CONSTITUTION: The temperature of oil in an engine is detected by a temperature sensor 1. Said temperature is input to a microcomputer, obtaining the injection timing of fuel. The microcomputer 8 gives a control signal to an oil pressure control valve 4 through an output interface 12. This oil pressure control valve 4, being inserted between a timing gear 13 and a rotary shaft 14 and applying a change of oil pressure to an actuator 5, controls a phase difference of rotation between the timing gear 13 and an injection pump 10. In this way, combustion of the engine is smoothed.