PURPOSE: To form a controller for preheating of a glow plug, which is simple in matching and high in control accuracy and also is not affected by the length, etc., of wire of wire harness with respect to the control characteristics, by using a system in which the voltage characteristics of the glow plug are compensated by detecting only the voltage applied to the glow plug.
CONSTITUTION: The potential VG of the connecting point A of a glow plug, showing the terminal voltage of the glow plugs 4W7, is applied to a level shift circuit 15 and made to shift-down by a fixed voltage Va by a constant-voltage diode 13. As a result, an output voltage VG'(=VG-Va) is sent out and applied to a simulation circuit 21 to generate a charging voltage on both ends of a condenser 16. On the other hand, when the output voltage VG' is zeroed, the charge of the condenser 16 is discharged through the glow plugs 4W7. The temperature characteristics of the glow plugs are simulated by charging and discharging actions, and the results are output in the form of a temperature voltage signal Vc which is in turn put in an electrification control circuit through comparator circuit to control the glow plugs with respect to electrification.
SUGIMOTO HITOSHI
ABE YOSHIAKI
| JPS5465225A | 1979-05-25 |