What are the symptoms of engine knocking?
1 Answers
Engine knocking can manifest as irregular metallic knocking sounds like "clunk," "click," or "clang" inside the engine, engine vibration, excessively high engine temperature, incomplete fuel combustion resulting in black smoke in the exhaust, reduced engine power, increased fuel consumption, and sudden changes in RPM during normal driving. Below is more information about knocking: 1. Causes of knocking: When the air-fuel mixture combusts in the combustion chamber, the flame spreads outward from the ignition point in a "wave" pattern, so it takes a brief period from ignition to complete combustion of the fuel-air mixture. 2. Knock sensor: The fastest and most effective way to suppress knocking is to retard the ignition timing, thereby reducing combustion pressure. The working principle of the knock sensor is that when engine knocking is detected, it delays the ignition timing to a point where knocking does not occur. Once the engine stops knocking, the ignition timing is gradually restored to its original setting. More advanced knock sensors can even identify which specific cylinder is knocking and individually adjust the ignition timing for that cylinder. 3. Basic concept: Detonation, also known as knocking, is a chemical reaction transmission process accompanied by a significant release of energy. The leading edge of the reaction zone is a shock wave moving at supersonic speed, known as a detonation wave. After the detonation wave passes, the medium becomes a high-temperature, high-pressure detonation product. Systems capable of detonation can be gaseous, liquid, solid, or mixed-phase systems such as gas-liquid, gas-solid, and liquid-solid. Typically, liquid and solid detonation systems are referred to as explosives.
