What are the causes of knocking sound in Great Wall C50 during rapid acceleration?
1 Answers
The main causes of knocking sound in Great Wall C50 during rapid acceleration are as follows: 1. Overly advanced ignition timing: To ensure the piston receives power immediately upon entering the power stroke after the compression top dead center, ignition typically occurs before the piston reaches top dead center (as it takes time for complete combustion). Excessively advanced ignition causes most of the fuel-air mixture to burn while the piston is still in the compression stroke, leading to high pressure and spontaneous combustion of the remaining mixture, resulting in knocking. 2. Excessive carbon buildup in the engine: Heavy carbon deposits in the combustion chamber not only increase the compression ratio (generating high pressure) but also create hot spots on the carbon surface, causing engine knocking. 3. Overheating engine: High intake air temperature due to a hot environment or poor engine coolant circulation can lead to engine overheating and knocking. 4. Incorrect air-fuel ratio: An overly lean fuel-air mixture raises combustion temperature, which increases engine temperature and makes knocking more likely. 5. Low fuel octane rating: The octane rating indicates a fuel's resistance to knocking. Higher octane fuels have better anti-knock properties. High-compression engines have higher combustion chamber pressures, making them prone to knocking when using low-octane fuel.
