The symptoms of cylinder knocking during operation of diesel generator are: from medium speed to low speed, a heavy cylinder knocking sound will be made, black smoke will be emitted from the exhaust pipe of diesel generator set, and there will be sound of gunfire or fire shooting from time to time, and the engine body will overheat. The main reasons for cylinder knocking are:

1. The fuel supply time is too early

When the piston of the diesel generator set moves upward and does not reach the specified injection position, the fuel injector starts to inject fuel, so that the fuel combustion is advanced. The high-pressure gas in the cylinder impacts the piston, making a rhythmic "click, click" sound, reducing the throttle, and the knock is obvious.

The elimination method is to adjust the fuel supply advance angle, that is, increase the gasket between the fuel injection pump and the gearbox to delay the fuel supply time until it meets the specified fuel injection time. For every 0.1mm increase in the gasket, the fuel supply advance angle can be delayed by 1.3-1.7.

Wear of oil outlet valve

After the wear of the oil outlet valve, on the one hand, the clearance between the pressure reducing ring and the inner hole of the valve seat becomes larger, the sealing becomes worse, and the pressure reducing effect becomes worse; On the other hand, the remaining pressure in the high-pressure fuel pipe is too high, causing an increase in fuel supply, causing fuel detonation and knocking the cylinder. The knocking sound is particularly noticeable when the throttle is reduced.