Abstract: A fuel injection timing control system is provided wherein a fluid actuator having a fluid chamber containing therein a movable wall member and the amount of pressure medium in the fluid chamber are controlled by electromagnetically operated control valve means to cause the actuator to operate an element for controlling the fuel injection timing of a fuel injection pump.

Abstract: There is provided a vehicle engine-driven alternator wherein an internal combustion engine is coarsely adjusted to a preset speed by an engine governor, the turning driving force of the engine is transmitted to an alternator through a magnetic slip coupling, and the excitation current to the magnetic slip coupling is controlled by an excitation control circuit which compares the number of revolutions of the alternator with a preset value to generate an output depending on the result of the comparison, thereby providing a source of alternating current having an extremely accurate preset frequency.