摘要 |
PURPOSE:To prevent a trouble before its occurrence in a plug, by providing a charging circuit in which a capacitor is rapidly charged with the quick stop of an electric current flowing in the glow plugs through a relay when the high terminal voltage above a preset level is applied to the glow plugs. CONSTITUTION:A voltage detecting circuit 10, both detecting the voltage of glow plugs G and controlling a relay 2 for electric conduction flowing an electric current in the plug G through a current limiting resistor 3, and a charging circuit, in which a capacitor is rapidly charged with the stop of the conduction of the electric current in the glow plug G through the relay 2 when high terminal voltage above a preset value is applied to the glow plug G, are provided in a current conduction control circuit 4. In this way, when overvoltage is applied to the glow plug G due to a cause such that a battery is placed in an overcharged condition, the conduction of the current in the glow plug G can be promptly stopped, and a trouble of the glow plug G can be prevented before its occurrence. |