Deflagration sensor
In addition to lowering the temperature to reduce the possibility of deflagration outside, but also knock transducer, and its role is in produce deflagration, feel abnormal vibration sensor information feedback immediately to the engine ECU (electronic control unit) control system, will be slightly delayed ignition timing, do not produce deflagration back to normal when the ignition timing.
This paper by guilin new ronghuang machinery co., LTD