Teach you how to extend the service life of diesel cylinders

At present, the average life of foreign diesel engines under normal conditions is more than 8000h. From the perspective of domestic use, there is still a certain gap in achieving the above indicators. One of the main faults is the early wear and tear of the cylinder liner, so solving this problem can greatly increase the service life of the diesel engine.

1. Correctly maintain and maintain the air filtration system

Failure of the air filtration system will cause the wear of the cylinder liner, which will greatly reduce the life of the cylinder liner. Therefore, there are higher requirements for air filtration, and multi-stage efficient air filters should be selected.

Always check and clean up the dust on each part to ensure that it is clean inside and outside. Damaged parts must be replaced in time to prevent abrasive particles from entering the cylinder liner. Ensure the tightness of the connection between the filter and the suction hose, and ensure that there is no air leakage between the turbocharger compressor outlet and the cylinder head.

2. Control of machine temperature

The corrosion and wear of the cylinder liner largely depends on the operating temperature of the diesel engine. The test shows that when the coolant temperature drops to 40-50℃, the wear of the cylinder liner will be 5-6 times the normal wear, and it is mainly corrosive wear, so keeping the cooling system working temperature not exceeding 90℃ will greatly limit Sulfur-containing vapor condenses on the cylinder liner wall to reduce corrosion.

3. Selection of diesel engine lubricating oil quality and viscosity

Diesel engines should select oils of CC and CD or higher according to the operating instructions, that is, according to the enhanced strength of the diesel engine and the working environment temperature.

4. Cavitation on the outer surface of the cylinder liner and antifreeze coolant

The gas in the cylinder is combusted, and the piston will swing from side to side in addition to the reciprocating linear movement in the cylinder, causing serious vibration of the cylinder liner. At this time, the cooling water in contact with the cylinder liner generates bubbles under vibration. Many pits were formed on the outer circle of the cylinder liner for a long time, which gradually expanded to form cavities, resulting in penetration of the cylinder wall. In order to prevent cavitation of the cylinder liner, in addition to taking measures in design and manufacturing, the following work must be done from the perspective of use, maintenance and repair:

1) Reduce the impact of the piston on the cylinder liner. Under the condition of ensuring basic lubrication, the gap between the piston and the cylinder liner should be as small as possible, and at the same time, ensure the verticality of the cylinder liner center during assembly.

2) Pay attention to the selection and replacement of antifreeze coolant, choose products with good anti-corrosion and anti-corrosion performance, and check frequently during use, and the replacement time should not exceed two years. To

5. Correct installation and use of cylinder liner, piston connecting rod group and crankshaft combination group

It should be carried out in strict accordance with the provisions of the diesel engine instruction manual. First of all, ensure the cleanliness of the cylinder liner and the body and other components and the assembly gap of each component. The weight of the pistons and connecting rods of the same diesel engine should be as consistent as possible and not exceed the tolerance. At the same time, ensure the tightening torque of various bolts and nuts value.

During the use of the crankshaft combination group, pay attention to whether the torsional vibration damper fails and whether the matching clearance of each bearing is out of tolerance to avoid abnormal vibration of the crankshaft and accelerate the early wear of the piston connecting rod group and the cylinder liner.

6. Reasonable selection of running-in specifications

Before the new engine or the overhauled diesel engine is officially used, it must be run-in according to the instructions of the user manual. Generally, it can be put into full-load use only after 60 hours of running-in operation. The purpose of running-in is to improve the working conditions of the moving parts of the diesel engine, and improve the reliability and service life. During the running-in period, the load should be 50%-80%, and the speed should be no more than 80% of the calibrated speed, and care should be taken not to operate under idling conditions for a long time. After the running-in is completed, the oil must be changed carefully. High idle speed and overload operation should be avoided during normal use.