| 摘要 |
PURPOSE:To prevent the plug from overheating by a method wherein a discharging circuit, simulating temperature decrease after stopping the conduction of the glow plug, is provided and the conducting time of the glow plug, which is determined from the cooling water temperature of the engine, is corrected based on the discharging voltage of the discharging circuit. CONSTITUTION:When a preheating switch becomes OFF during the conducting period of the glow plug 11, impression of the voltage of a battery 14 on the discharing circuit 15a, provided so as to simulate the temperature decrease after the stopping of the conduction of the glow plug 11, is stopped, the capacitor C of the circuit 15a discharges through resistors R2, R3 and the manner of discharging voltage drop becomes same as the manner of the temperature decrease of the glow plug 11. When the preheating switch becomes ON again, the temperature rise of the glow plug 11 due to the conduction of previous time is considered and a correcting coefficient, having a value smaller than the same in case the temperature of the glow plug 11 is low, is selected to set the shorter conducting period of time of the plug 11. According to this method, the overheat of the glow plug 11 may be prevented and the durability of the same may be improved. |
