Circuit Description

A flat type knock sensor (non-resonant type) can detect vibrations in a wide band of frequency (about 6 kHz to 15 kHz) and has the following features:

• Knock sensors are fitted on the cylinder block to detect the engine knocking.
• The sensor contains a piezoelectric element which generates a voltage when it becomes deformed, which occurs when the cylinder block vibrates. If engine knocking occurs, the ignition timing is retarded to suppress it.