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Why should the fuel supply advance angle of diesel generators not be too early?

April 20, 2022
The size of the fuel injection advance angle has a great influence on the operating condition of the diesel engine. When the fuel injection advance angle is too large, the fuel preparation period will be longer and the engine will work rough. If the fuel injection advance angle is too small, the combustion process will be delayed too much, the maximum pressure value will drop, and the thermal efficiency of the diesel engine will drop significantly.
Some maintenance personnel of diesel generator sets often prefer to adjust the fuel supply advance angle of the inline pump diesel engine earlier, and some even exceed the specified value by 2°-3°. They think that the fuel supply advance angle is adjusted a little earlier, and the diesel engine works vigorously (high power). But too early fuel supply advance angle is as toxic to diesel engine work as too late fuel supply advance angle.
There are:
1. Excessive burst pressure makes high-temperature gas easily penetrate into the lower crankcase, resulting in high-temperature fission of the oil, and the oil is easily evaporated into oil and gas, resulting in carbonization of the oil in the crankcase.
2. The rapid combustion of excess fuel in the cylinder will increase the thermal load on the top of the piston, causing overheating damage to the piston.
3. The vibration of the cylinder liner is intensified, which accelerates the cavitation of the cylinder liner and the body, resulting in damage.
4. It will cause knocking of the cylinder, increase the impulse of the piston on the cylinder liner, aggravate the vibration of the cylinder liner, and cause fatigue damage to the cylinder liner.
5. The premature fuel supply advance angle will cause too much fuel accumulated in the cylinder before the top dead center, and the explosion pressure will increase a lot after combustion, which will increase the mechanical load of the piston connecting rod and cause damage to these parts.
6. Excessive thermal load will cause cracks in the cylinder head and deformation of the valve seat ring.