| 摘要 |
PURPOSE:To detect the disconnection of the glow plug quickly and correctly by a method wherein the differences of levels of electric signals of respective glow plugs, energized by electric powers, are detected for respective groups thereof and detection of disconnection is effected when the difference has exceeded a predetermined value. CONSTITUTION:When the glow plug GP1 among the glow plugs GP1-GP4 is disconnected, the voltage Va of the group 1 becomes higher than the voltage Vb of another group 2. According to the difference, an output voltage V12 in the line 14 of a subtracting circuit 11 is increased and the value thereof becomes larger than a reference level determined by resistors T12, R13 in a comparating circuit 16. Accordingly, the transistors Q1, Q2 of a driving circuit 20 are conducted and an indicating lamp 21 is luminated. According to this method, the disconnection of the glow plug may be detected quickly and correctly without waiting until the electric power energizing of the glow plug is stabilized. |
