Service HotlineThe inner surface of the ceramic cylinder liner is directly affected by high-temperature and high-pressure gas, and always experiences high-speed sliding friction with the piston ring and piston skirt. The appearance comes into contact with cooling water, causing severe thermal stress under large temperature differences and corrosion by the cooling water. The lateral thrust of the piston on the ceramic cylinder liner not only intensifies its internal friction, but also causes it to bend. When the lateral thrust changes direction, the piston also collides with the ceramic cylinder liner.
In addition, it is subjected to significant installation preload force. The gas pressure causes tangential tensile stress and radial compressive stress on the cylinder wall, and the inner surface is large, all of which are high-frequency pulsating stresses. The functions of ceramic cylinder liners are:
1. Together with the cylinder head and piston, it forms the working space of the cylinder.
2. The ceramic cylinder liner of a cylindrical piston diesel engine bears the lateral thrust of the piston and becomes the lead for the reciprocating motion of the piston.
3. Transfer the heat from the piston assembly and itself to the cooling water to ensure an appropriate operating temperature.
4. The ceramic cylinder liner of a two-stroke diesel engine is equipped with air ports, which are opened and closed by the piston to achieve valve distribution.
Due to the large thermal stress caused by the temperature difference between the inside and outside of the cylinder wall, compressive stress is generally generated on the inner surface at high temperatures, while tensile stress exists on the cooling surface. But at extremely high temperatures, the metal near the inner surface undergoes creep plastic deformation, and residual tensile stress is formed on the inner surface after cooling. This low-frequency stress caused by changes in starting and stopping can cause material fatigue.
Reduce ceramic cylinder liner: 1. Measures to reduce wear. Strengthening the maintenance of filters to maintain good working condition of air filters, oil filters, and fuel filters is crucial for reducing the wear of ceramic cylinder liners. Strengthening the maintenance of the "three filters" is an important measure to prevent mechanical impurities from entering the cylinder, reduce cylinder wear, and extend the service life of the engine, especially in rural and windy areas. Some drivers are wrong to not install air filters in order to save fuel.
2. Choose lubricating oil correctly. Lubricants with viscosity values should be selected strictly according to the season and engine performance requirements. It is not allowed to purchase inferior lubricating oil at will, and the quantity and quality of lubricating oil should be regularly inspected and maintained.
3. Maintain the normal operating temperature of the engine. The normal operating temperature of the engine should be 80-90 ℃. If the temperature is too low to maintain good lubrication, it will increase the wear of the cylinder wall. The water vapor inside the cylinder is prone to condense into water droplets, dissolve acidic gas molecules in the exhaust gas, and generate acidic substances, thereby causing corrosion and wear of the cylinder wall. Experiments have shown that when the cylinder wall temperature drops from 90 ℃ to 50 ℃, the cylinder wear is four times that of 90 ℃. Excessive temperature can reduce the strength and wear of the cylinder, and even cause the piston to expand excessively, resulting in "cylinder expansion" accidents.
4. During cold start of the engine, insufficient oil supply from the oil pump may occur due to low oil temperature, high viscosity, and poor fluidity. At the same time, the oil on the original cylinder wall flows downwards along the cylinder wall after parking, and cannot obtain the same good lubrication as during normal operation at the moment of starting, greatly increasing the wear of the cylinder wall during starting. So when starting, the engine should idle a few times and wait for the friction surface to lubricate before starting. After starting, idle and preheat. It is strictly prohibited to forcefully tap the oil port. Wait until the standby oil temperature reaches 40 ℃ before starting. When starting, you should stick to low gear and drive a certain distance in each gear until the oil temperature is normal before switching to normal driving.
5. Improve warranty quality. During use, promptly eliminate any problems and replace or repair damaged or deformed parts at any time. When installing ceramic cylinder liners, strict inspection and assembly should be carried out according to technical requirements. In the operation of replacing the warranty ring, a piston ring with appropriate elasticity should be selected. If the elasticity is too small, it will cause gas to enter the crankcase, blow off the oil on the cylinder wall, and increase the wear of the cylinder wall; Excessive elasticity can directly exacerbate the wear of the cylinder wall, or damage the oil film on the cylinder wall and exacerbate its wear.
