IGNITION COIL FOR INTERNAL COMBUSTION ENGINE

摘要

Provided is an ignition coil for an internal combustion engine that is capable of continuing discharge even if secondary current wiring is disconnected or a current detection resistor is disconnected. A secondary current detection resistor (51) that detects secondary current flowing to a secondary circuit that comprises a secondary coil (12) and an ignition plug (50) is disposed externally. Provided are the following: a high-pressure diode (14) that is connected to one end of the secondary coil (12) and that establishes the direction in which secondary current flows; and a Zener diode (15) that is connected to the connection point between the secondary current detection resistor (51) and the high-voltage diode (14) so as to have polarity opposite to that of the high-voltage diode (14). When a breakdown occurs in which the secondary current flowing to the secondary current detection resistor (51) is cut off or suppressed, the Zener diode (15) forms a secondary current path leading current flowing through the high-voltage diode (14) to the ignition plug (50) by using the avalanche breakdown phenomenon, and causes the ignition plug (50) to produce a discharge spark (50).