Piezoelectric Ceramic Sensor-Knock Sensor

Knock sensor is used to detect the engine engine block deflagration strength. Once the deflagration occurs, the ECU is instructed to delay the ignition and turn to the closed timing control of the ignition timing in order to adjust the ignition timing.

Installed in the cylinder on the specific detection of the engine deflagration conditions, provided to the ECU according to the signal to adjust the ignition advance angle. The main component is a piezoelectric ceramic crystal, which makes an inertia counterweight compacted with a piezoelectric ceramic crystal sheet. When the deflagration occurs, the deflagration pressure wave compresses and deforms the piezoelectric ceramic crystal chip through the inertia counterweight, resulting in a much larger voltage signal than the non-deflagration. In order to avoid misjudgment caused by interference, a judgment interval is set according to the ignition timing.

The knock sensor can detect knocking by detecting cylinder pressure, engine body vibration and combustion noise. When the engine deflagration occurs, the sensor will generate the corresponding electrical signal, and sent to the electronic controller, the electronic controller through the ignition delay method to eliminate engine deflagration.

Mainly magnetostrictive and piezoelectric ceramics. The magnetostrictive detonation sensor has a temperature of -40 ° C to 125 ° C and a frequency range of 5 to 10 kHz. The piezoelectric knock sensor has a sensitivity of 200 mV / g at a center frequency of 5.417 kHz, G ~ 10g range with good linearity.