| Knock symptom | The symptoms of cylinder knocking of diesel generator during operation are: from medium speed to low speed, it will make a heavy cylinder knocking sound, the exhaust pipe of diesel generator sets will emit black smoke, and sometimes there will be gunfire or gunfire, and the engine body will overheat. The main reasons for cylinder knock 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, making the fuel burn ahead of time. The high-pressure gas in the cylinder impacts the piston, making a rhythmic "clack, clack" sound on the cylinder. Reduce the throttle, and the knock is obvious. The elimination method is: 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 to meet the specified fuel injection time. The oil supply advance angle can be delayed by 1.3-1.7 for every 0.1 mm increase in the gasket. 2. Poor fuel combustion Low injection pressure, fuel dripping from the injector, poor atomization of the fuel injection, and too late fuel supply will cause poor fuel combustion and cause cylinder knock. The cylinder knocking sound caused by such faults is low and hoarse, accompanied by engine overheating, black smoke or exhaust pipe blasting, flame spraying and other phenomena. The fuel injector shall be removed for inspection and adjustment, and the fuel supply time shall be adjusted. If necessary, a new part shall be replaced to make it meet the requirements. 3. The oil outlet valve is worn After the outlet valve is worn, 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, if the residual pressure in the high-pressure fuel pipe is too high, the fuel supply will increase, causing fuel deflagration and knocking. The knocking sound is especially obvious when the accelerator is reduced. |
