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 the diesel generator set will emit black smoke, and sometimes there will be sound of gunfire or outward fire, and the engine body will overheat

Reason for cylinder pulling:

The reasons for cylinder pulling are very complex, with design factors such as material selection, determination of gap size, appropriateness of device installation, reasonable structural layout, surface roughness, and perfect lubrication and cooling arrangements. From a management perspective, it may be caused by the following reasons:

(1) Poor cylinder lubrication:

The cylinder is not lubricated enough or the oil supply is interrupted, and the cylinder is pulled due to direct metal contact. The reasons for poor cylinder lubrication include: too little oil in the oil pan or poor oil quality, too high temperature of the diesel engine, or damage or failure of the piston ring (mainly the oil ring).

(2) Insufficient running-in:

To achieve effective break-in in the shortest possible time, it is necessary to consider the issues of break-in time and load distribution. Even if the break-in is carried out for a long time under low loads, it cannot be completed. However, if the engine is in a hurry to operate at high loads, it may cause cylinder pulling. Therefore, during the diesel engine break-in period, it should be noted that the amount of oil injected should be appropriately increased; After the piston ring is renewed, it should run under low load for a period of time; After replacing the piston and cylinder liner, they should be run in before increasing the load for operation.

(3) Poor cooling:

Poor cooling will result in excessively high temperature of the cylinder and piston, and poor lubrication; Poor cooling can cause excessive expansion and deformation of the piston and cylinder liner due to overheating, loss of the original normal clearance, and cylinder pulling. The reasons for poor cooling include insufficient discharge pressure of the cooling water pump, insufficient or interrupted water supply; Rust or dirt in the cooling water chamber; Water contains bubbles that accumulate in the cooling chamber but are not released, resulting in air resistance; The water quality is too dirty and the water temperature is too high.

(4) Abnormal operation of piston ring:

The opening clearance is too small, causing the piston ring to break; The clearance between heaven and earth is too small, which makes the piston ring stuck; Too much carbon deposits cause the piston ring to stick to the ring groove and lose elasticity, resulting in fracture or gas leakage; The opening clearance is too large or the wear is serious, resulting in gas leakage. The gas leakage damages the lubricating oil film, resulting in high surface temperature. After the piston ring is broken, the debris is easy to fall into the piston cylinder, causing cylinder pulling and cylinder biting.