| 摘要 |
PROBLEM TO BE SOLVED: To solve such a problem that, when noises generated from an alternator are superposed on an ion current waveform in the case of determining knock generated in an internal combustion engine from an ion current generated in a cylinder after the combustion of the internal combustion engine, they are erroneously determined as the knock.SOLUTION: A secondary coil 12 is connected at its low pressure side via a second diode 52b to a first Zener diode 50a, and the secondary coil 12 is connected at its high pressure side via a second Zener diode 50b to an ignition plug 40. A capacitor 54 is connected in parallel to the first zener diode 50a, a first diode 52a is connected among the capacitor 54, a connection part of the first Zener diode 50a, and the ignition plug 40, and the low pressure side of the secondary coil and a connection part of the second diode 52b are grounded via a resistance 56. The second Zener diode 50b is connected at its anode side to the secondary coil 12, and the second diode 52b is connected at its cathode side to the secondary coil 12. |
