What are the three methods for detecting engine knock?

[SanVictoria]

Detecting cylinder pressure, detecting engine vibration, and detecting cylinder temperature. Here is the relevant information: 1. Knock: Knock, commonly known as piston slap or pinging. Knock is an abnormal combustion phenomenon that occurs during the engine combustion process. Simply put, "knock" is an abnormal combustion phenomenon in the engine. Knock is caused by abnormal combustion leading to abnormal pressure in the combustion chamber. When knock occurs, the engine produces a knocking sound. 2. Installation location: The knock sensor is placed in different positions on the engine block or cylinder. When vibration or piston slap occurs, it generates a small voltage peak; the greater the piston slap or vibration, the larger the peak voltage produced by the knock sensor. A certain high frequency indicates knock or piston slap. Knock sensors are usually designed to measure frequencies in the range of 5 to 15 kHz.