| 摘要 |
PURPOSE:To enable high-precise control of temperature, by a method wherein a stable preheating circuit is connected in parallel to a rapid preheating circuit to rapidly preheat a glow plug, and actuation of the stable preheating circuit is controlled according to a voltage applied on the glow plug during stable preheating. CONSTITUTION:A rapid preheating circuit is formed such that an on-off element 2 is connected in series between a glow plug 1, having given resistance temperature characteristics, and a power source 3. A stable preheating circuit formed with an on-off element 10 and a resistor 11 is connected in parallel to the rapid preheating circuit. During closing of the on-off element 10, an applying voltage on the glow plug 1 is detected by a voltage detecting means 6, and the drive time of the on-off element 10 is decided by a drive time of the on-off element 10 is decided by a drive signal control means 12 according to an output from the voltage detecting means. The energizing time of the glow plug 1 is computed by a computing means 7 according to an output from a glow plug temperature detecting means 5, and a correction amount of the energizing time is computed by a computing means 8 according to an output from the voltage detecting means 6. According to the computing value, the energizing time of an on-off element 2 is computed by an on-off element drive signal computing means 9.
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