| 摘要 |
PURPOSE:To preheat glow plugs for a suitable time so as to prevent their breaking, by connecting a current control resistor, connected in parallel to a voltage dropping resistor and having a positive resistance-temperature coefficient, and a heating unit, which heats this current control resistor, in series to the glow plugs. CONSTITUTION:If a preheater switch 2 is closed, an electric current from a battery 1 is allowed to flow in a current control resistor 4 to glow plugs 7a-d, rapidly causing their temperature rise. After a certain time, the current control resistor 4 causes its resistance value to increase by receiving heat from a heating unit 5 together with heating by itself, and the electric current is allowed to flow in a voltage dropping resistor 6, applying an approximate rated voltage to the glow plugs. In this way the glow plug can be rapidly preheated for a suitable time, by enabling an excessive temperature rise to be prevented. |
