What are the causes of car detonation?

[VanAngelina]

Here are the causes of car detonation: 1. Excessive carbon deposits: Too much carbon buildup in the engine combustion chamber reduces its effective volume, increasing the compression ratio. The heat-retaining and non-conductive properties of carbon deposits cause premature combustion of the fuel-air mixture, weaken the swirl intensity at the end of compression, prolong combustion time, increase the tendency for spontaneous ignition, leading to detonation. 2. Engine overheating: Prolonged operation at high power, overload conditions, or continuous driving at low gear with high speed can lead to poor heat dissipation and engine overheating. When the overheating is severe and not promptly addressed, the incoming fuel-air mixture gets preheated, causing localized high temperatures that reach the ignition point prematurely, resulting in spontaneous combustion before normal ignition. 3. Improper fuel usage: Lower-grade gasoline has poorer anti-knock properties. Gasoline stored for too long or improperly sealed will naturally lose octane value, worsening its anti-knock performance. If mistakenly used, it can lead to incomplete combustion, where the initially burning mixture expands and compresses the remaining unburned mixture to its auto-ignition temperature, causing sudden high-pressure explosive combustion.