Why does the engine knock?

When the engine is working, the engine will knock due to the influence of excessive ignition advance time (ignition advance angle), engine load, temperature, fuel quality and other factors. When knocking happens, because the gas burns before the piston moves to the top dead center, it will produce noise and reduce the power of the engine, and it will damage the mechanical parts of the engine in the worst case.

In order to prevent the occurrence of knocking, the knock sensor is an essential component, so that the ignition advance time can be adjusted by the electronic control system.

When the engine knocks, the knock sensor converts the mechanical vibration of the engine into signal voltage and sends it to ECU. According to the pre-stored ignition data, ECU calculates and corrects the ignition advance angle in time to adjust the ignition timing and prevent knocking.

Extended data:

Because people usually use the fuel consumption of 100 kilometers to evaluate the fuel consumption exceeding the standard, instead of just referring to the specific fuel consumption of the engine, when diagnosing the fuel consumption exceeding the standard, we must first diagnose whether the fault is in the engine.

Bad driving habits of drivers, too low tire pressure, too heavy vehicle load, delayed braking, slipping transmission system, inability to upgrade the automatic transmission, and locking of hydraulic torque converter will all lead to high fuel consumption.

Faults that lead to insufficient power, too rich mixture and too low coolant temperature will lead to too high engine fuel consumption. Excessive engine idle speed is also one of the reasons for high fuel consumption.