Malfunction i.e. ignition wire disconnection, detecting device for combustion heat engine of motor vehicle, has detecting unit for detecting appearance of over voltage at ignition coil, where unit has diode assembled in series with resistor

摘要

The device (24) has a detecting unit formed by a zener or transient voltage suppressor diode (14) and a resistor (23). The diode is assembled in series with the resistor. Another zener diode is connected parallel to the resistor. The detecting unit detects the appearance of over voltage at the level of an ignition coil (7). The diode is connected such that the voltage at a primary winding (8) of the coil is limited, when the voltage exceeds a determined threshold. An independent claim is also included for a method for detecting malfunction of a spark producing system.