| 摘要 |
PURPOSE:To enable a glow plug to be prevented from its overtemperature, by providing a charging circuit in which a capacitor is charged with the stop of electric conduction of a current in the glow plug through a relay when an input to a voltage detector circuit of terminal voltage of the glow plug is stopped. CONSTITUTION:A voltage detector circuit 10, both detecting the voltage of a terminal in the power supply side of a glow plug G and controlling a relay 2, and a capacitor charging circuit, in which is capacitor is charged with the stop of electric conduction of a current in the glow plug G through the relay 2 when an input to the voltage detector circuit 10 of terminal voltage of the glow plug G is stopped, are provided in a current conduction control circuit 4. In this way, when the measured voltage of the glow plug G is not input to the voltage detector circuit 10 because of disconnection or the like of the wire harness, the current conduction through the relay 2 can be stopped in a short time, and the glow plug G, which concurrently receives combustion heat and Joule heat from an engine, can be prevented from the overtemperature. |
