PURPOSE: To make the stable and sure detection of knocking possible without the need for matching the resonance frequencies of a knocking detector by inputting the oscillation outputs of said detector to a resonance circuit and fetching them out.
CONSTITUTION: Since a detector 2 is clamped to a cylinder block by means of a screw part 21a, the oscillations by knocking are transmitted through a housing 21, a base 18, and a bolt 17 to a weight 15. As this weight 15 oscillates, oscillation stresses are exerted upon piezoelectric elements 13, 14. The signal voltages generated in the elements 13, 14 are outputted through a central electrode 12 then through a terminal 29a to a resonance circuit 2a. Since the oscillator consisting of the weight 15 has a resonance point at the frequency deviated considerably from the knocking frequency band, the output voltages are almost constant. The circuit 2a consists of a coil 6 and a capacitor 7. If the resonance frequency is set roughly at 8kHz with the parallel resonance circuit, a large output voltage is generated at the resonance point with respect to the input of the signal voltage from the detector 2.
MIYAHARA MASAHIKO
KATOU MINORU
| JPS5788328A | 1982-06-02 |