What is the function of a knock sensor in an engine?

The function of a knock sensor in an engine is primarily to adjust ignition timing. Knock sensors are designed to detect engine knock, which is a knocking or pinging sound that occurs when the air-fuel mixture in a cylinder detonates at the wrong time. When the knock sensor detects this abnormal combustion, it sends a signal to the engine control unit (ECU), which then adjusts the ignition timing to optimize performance, prevent engine damage, and improve efficiency. By retarding the timing, the ECU can help reduce knock and restore smooth engine operation.

The other options, although they might seem relevant to engine operation, do not accurately describe the function of a knock sensor. For instance, detecting engine temperature, measuring fuel quality, and monitoring oil levels are performed by distinct sensors and systems specifically designed for those tasks, but they are not the role of a knock sensor. The capability of the knock sensor to influence ignition timing is critical for ensuring that the engine runs smoothly and efficiently, enhancing overall performance and longevity.