What is the reason for cylinder pulling in diesel generator sets?

Pulling a vat "is also called" biting a vat "by some people. It is a striped and colored damage that appears on the surface of the cylinder and piston ring along the direction of piston movement. When a cylinder is pulled, the wear of the cylinder liner is very severe, reaching tens or even hundreds of times the normal wear.
After the cylinder is pulled, the external characteristics of the diesel engine are a change in sound and black smoke from the exhaust. The consequence is that the working surfaces of the piston, piston ring, and cylinder liner are damaged, the gas seal fails, the consumption of oil and the amount of gas leakage rapidly increase, making the engine unable to operate normally, and even stopping in a short period of time due to the piston, piston ring, and cylinder liner biting.

The main reason for pulling the cylinder is actually due to the surface of the piston, piston ring, and cylinder liner being "welded" and pulled due to high temperature. Dry friction occurs between the piston and the cylinder liner due to the interruption of the oil film, and the hot friction heat causes the micro melting and adhesion of the metal, tearing off nearby metal particles. The most fundamental reason for cylinder pulling is the interruption of the oil film. According to the requirements of gas sealing, the gap between the piston ring and the cylinder liner should be as small as possible, which makes their lubrication conditions very unfavorable. The friction between the cylinder liner and the piston ring depends on the elasticity of the piston ring, working temperature, sliding speed, oil film distribution, quality of the parts, and running in condition. When the contact surface is overloaded, causing severe friction between the cylinder liner surface and the piston ring working surface due to direct contact, a large amount of frictional heat is generated, causing the temperature of the working surface to rise sharply. The consequence is that the two friction surfaces fuse and adhere, causing strain.
From this, it can be seen that poor fuel supply, severe gas leakage, and excessive contact stress on parts that damage the oil film are the main causes of cylinder pulling. In addition to lubrication, clearance, and manufacturing quality of parts, failure to use may also cause cylinder pulling. Specifically, there are the following points:
1. The clearance between the piston and cylinder liner is too small, or it has not undergone good running in before formal load operation.
2. Poor lubrication, such as small clearance, thin engine oil, or failure to apply oil during assembly.
3. Overheating of diesel engine.
4. The body is not clean or the piston is installed too tightly during assembly.
5. Poor quality of pistons and piston rings.
From a usage perspective, it is also important to avoid sudden increases in load or emergency stops. Before starting, it is best to use a crank to rotate the crankshaft a few times to maintain a certain amount of lubricating oil on the friction surface.