What is the purpose of a car knock sensor?
3 Answers
The purpose of a car knock sensor is to detect engine knock and prevent the occurrence of knock phenomena. The symptoms of a damaged knock sensor include: 1. Reduced engine power accompanied by knocking sounds from the engine; 2. Potential damage to engine pistons and cylinder blocks, failure to detect engine detonation signals, and inability to automatically retard ignition timing. The working principle of a knock sensor is that when vibration or knocking occurs, it generates a small voltage peak. The more severe the knocking or vibration, the larger the main peak voltage produced by the knock sensor. A certain frequency indicates knock or detonation, and when the control unit receives this frequency, the ECU readjusts the ignition timing to prevent further knocking.
Last time I was fixing my friend's car, the knock sensor was broken. It mainly monitors the knocking sound during the engine combustion process. Once the sensor detects abnormal vibrations, it sends a signal to the computer, which immediately adjusts the ignition timing to delay slightly, preventing internal engine damage. This thing is really important. Without it, the engine can easily overheat, fuel consumption increases, and over time, it can damage the pistons or cylinder head. I remember during that repair, I also checked if the wiring was loose and if the signal voltage was normal. Modern cars rely on this to improve fuel efficiency and extend engine life, so regularly checking the sensor's condition is a smart habit to keep driving smooth and safe.
My old car used to make knocking sounds when climbing hills, which was engine knocking. The purpose of a knock sensor is to monitor this abnormal combustion in real time. When it detects vibrations, it immediately alerts the car's computer, which then retards the ignition timing to prevent engine damage. This helps a lot by preventing loss of power or a spike in fuel consumption. In daily use, if the sensor fails, the engine becomes unstable. I once had the check engine light come on, and only after timely repairs did I feel safe driving again. I recommend car owners not ignore small issues. Although it works in the background, proper maintenance can save a lot of trouble and money.
