| 摘要 |
PURPOSE:To keep off any life reduction and chainlike disconnection in a glow plug, by installing a signal generating device which generates a significant signal at a time when a voltage ratio between terminals of the flow plug and a voltage dropping resistor is in the specified condition. CONSTITUTION:A main relay 3 directly impresses a glow plug 6 with battery voltage, while a sensing resistor 5 detects temperature in the glow plug 6. A glow plug temperature detection circuit 7 detects a voltage ratio between the sensing resistor and the glow plug 6 whereby if the glow plug temperature is more than the desired upper limit value, it outputs a high level signal to the output 7a. At the stage that one glow plug is disconnected, it can accurately detect the glow plug disconnection and simultaneously allows the glow plug to make its temperature go up. With this constitution, a series of chainlike disconnection and deterioration in th glow plug are preventable without entailing any damage to the starting properties of an engine. |
