What causes engine knocking?
3 Answers
Engine knocking occurs due to the following reasons: 1. Carbon deposits in the combustion chamber; 2. Low octane rating of the fuel; 3. Incorrect ignition timing; 4. Overheating of the engine; 5. Incorrect air-fuel ratio. Solutions to engine knocking include: 1. Delaying the ignition timing; 2. Cleaning the fuel system and injectors; 3. Using qualified fuel additives; 4. Choosing fuel suitable for the engine's compression ratio; 5. Repairing or replacing the water pump. Engines are categorized by their working principles into piston engines, ramjet engines, rocket engines, and turbine engines. Their function is to convert thermal energy into mechanical energy by burning fuel in a sealed cylinder, causing the gas to expand and push the piston, thereby providing power to the vehicle.
Last time when I was driving uphill, I suddenly heard a knocking sound from the engine, like someone was hammering the cylinder walls. This kind of engine knocking is mostly caused by premature self-ignition of fuel in the cylinders, fighting against normal combustion. Common reasons include using low-octane gasoline or excessive carbon deposits increasing the compression ratio. Worn spark plugs or incorrect ignition timing can also cause trouble. Once I tried to save money by using 92-octane fuel, and the engine knocked when climbing hills. After switching back to 95-octane, it immediately became quiet. Remember to clean carbon deposits regularly, press the throttle gently, and avoid keeping the engine under high load for long periods.
My mechanic friend told me that knocking is caused by issues in the combustion process. Using gasoline with an insufficient octane rating makes it prone to premature ignition under high temperature and pressure, causing explosions before the piston reaches its proper position. When these opposing forces collide, it creates a knocking sound. Incorrect air-fuel mixture, overly advanced ignition timing, and excessive carbon buildup in the combustion chamber can all contribute to knocking. Engine overheating in summer also increases the likelihood of knocking. After cleaning the fuel injectors and throttle body, my knocking issue improved significantly. It's recommended to inspect the spark plugs every 20,000 kilometers, as a faulty knock sensor can also trigger error codes.
