| 摘要 |
PURPOSE:To prevent the deterioration of the durability due to the overheating at the heating coil section, by employing the two stage heating of the glow plug where the heat setting resistance at the first stage is made high while it is made low at the second stage. CONSTITUTION:Upon closing of a key switch 2, the super-quick heating of the glow plug 1 is started through a relay contact rl1 to increase the resistance Rg of the heating coil as the temperature rise thus to increase the potential (a) of the bridge circuit and upon reaching to the predetermined level Rs the relay drive 5 is functioned by a comparator C1 through OR gate 3 and delay circuit to open the contact rl1 for the time of the output width of a one-shot multivibrator thus to stop the quick heating and to close the contact rl2a, rl2b resulting in the second bridge circuit comprising the resistors Rg, Re, R3, R4. Upon completion of the output width time, the contact rl1 will reopen to supply the heating current while when the value of Rg reaches to the predetermined value RN the relay drive 5 is functioned by the comparator C2 thus to open the contact rl1 and to stop the heating. |
