ENGINE WITH KNOCK SENSING APPARATUS HAVING MULTIPLE FREQUENCY TUNING

摘要

D-4,666 C-3306 ENGINE WITH KNOCK SENSING APPARATUS HAVING MULTIPLE FREQUENCY TUNING A spark ignited internal combustion engine includes knock sensing apparatus comprising vibration sensing apparatus having a portion mounted on an engine component for vibration therewith and a tuned response to vibrations of a plurality of the acoustic cavity resonance frequencies of the engine cylinders. A separate signal processing channel is provided for the sensor output at each of the frequencies to indicate significant vibrations at the respective frequency. Coincidence means fed by all channels produce an engine knock signal only when significant vibrations are detected on all channels simultaneously.