①The filtration efficiency of the air filter is reduced.
The function of an air filter is to filter dust and particles from the air. When a car is driving, the air along the road inevitably contains dust and particles, and if these particles are sucked into the cylinder in large quantities, it will cause serious wear on the upper part of the cylinder. When the road surface is dry, the dust content in the air on a good highway is 0 01g/m3, the dust content of the air on the dirt road is 0 45g/m3. Simulate the situation of a car driving on dirt roads and conduct diesel engine bench tests, artificially allowing the diesel engine to inhale a dust content rate of 0 After working for only 25-100 hours with 5g/m3 of air, the wear limit of the cylinder can reach 0 3-5 mm. From this, it can be seen that the presence or absence of an air filter and the filtering effect are important factors determining the service life of the cylinder.
② The filtering effect of the oil filter is poor.
Due to the uncleanness of the engine oil, oil containing a large amount of hard particles will inevitably cause abrasive wear on the inner wall of the cylinder from bottom to top.

③The quality of lubricating oil is poor.
If the sulfur content of the lubricating oil used in diesel engines is too high, it will cause strong corrosion of the first piston ring at the top dead center, resulting in corrosive wear. The wear amount increases by 1-2 times compared to the normal value, and the particles peeled off by corrosive wear can easily cause severe abrasive wear in the middle of the cylinder.
④ Cars are overloaded, overspeed, and operate under heavy loads for a long time. Overheating of the diesel engine deteriorates the lubrication performance.
⑤ The water temperature of the diesel engine is too low to maintain normal water temperature, or the thermostat is blindly removed.
⑥ The running in period is too short, and the inner surface of the cylinder is rough.
⑦ The cylinder has poor quality and low hardness.