Engine cylinder liner and piston ring is a pair of friction pairs working under the conditions of high temperature, high pressure, alternating load and corrosion. Long term work in the complex and changeable situation, the result is the cylinder liner wear deformation, affecting the engine power, economy and service life. It is very important to analyze the cause of cylinder liner wear and deformation to improve the economy of the engine.
Analysis of the wear of cylinder liner
The working environment of the cylinder liner is very bad, and there are many reasons for wear. Usually due to structural reasons for normal wear and tear, but the use and maintenance of improper, will cause abnormal wear.
1 structural causes of wear and tear
1) poor lubrication conditions, so that the upper cylinder liner wear serious. The upper part of the cylinder liner is adjacent to the combustion chamber, the temperature is very high, and the lubrication condition is poor. The erosion and dilution of fresh air and non vaporized fuel, which aggravate the deterioration of the upper condition, make the cylinder on the dry or semi dry friction state, which is the cause of the wear of the cylinder head.
2) the upper part of the pressure, so that the cylinder wear on the heavy light. In the spring and back pressure under the action of pressure in the cylinder wall tight piston ring is more pressure, oil film formation and maintenance more difficult, mechanical wear. In the work stroke, with the piston down, the positive pressure gradually decreased, so the cylinder wear was heavier and lighter.
3 mineral acid and organic acid corrosion and spalling of the cylinder surface. The combustible mixture in cylinder combustion, produce water vapor and acid oxide dissolved in water, they generate mineral acid, organic acid generated in combustion and the corrosive effect on the cylinder surface, corrosion gradually by the piston ring scrape in friction, resulting in deformation of the cylinder sets.
4) into mechanical impurities, so that the central cylinder wear increased. The dust in the air, the impurity in the lubricating oil, into the piston and cylinder wall caused by abrasive wear. When the piston moves in the cylinder with dust or impurities, because of the maximum velocity in the middle of the cylinder, the wear of the cylinder is aggravated.
2 improper use of wear
1) oil filter filtration effect is poor. If the oil filter does not work properly, the lubricating oil are not effectively filter, lubricating oil contains a lot of hard particle will make the cylinder wear is intensified.
2) air filter efficiency is low. The function of the air cleaner is to remove the dust and sand from the air entering the cylinder to reduce the wear of the cylinder, piston and piston ring. The experiment shows that if the engine does not have air filter, the wear of the cylinder will increase 6-8 times. The air cleaner is not a long-term cleaning and maintenance, cleaning effect is poor, the cylinder liner wear will accelerate.
3) long time low temperature operation. For a long time low temperature operation, one is caused by combustion, carbon deposition from the top of the cylinder sleeve began to spread, so that the top of the cylinder liner to produce severe abrasive wear; two is caused by electrochemical corrosion.
4) often use inferior lubricating oil. Some owners to save money, often at the roadside shop to buy or sell illegal oil inferior oil, resulting in strong corrosion of the upper cylinder, the wear volume is 1-2 times larger than the normal value.
3 wear and tear caused by improper maintenance
1) Baotou beiben cylinder installation accessories improper location. When installing the cylinder sleeve, if the installation error, the cylinder centerline and the crankshaft axis is not perpendicular to the cylinder sleeve will cause abnormal wear.
2) the hole deviation of the connecting rod of the connecting rod. In the process of repair, reaming connecting rod copper sleeve, reamer tilt caused by deflection of connecting rod copper sleeve hole, a piston pin connecting rod center line and the center line is not parallel, forcing the piston to the cylinder liner a side tilt, can also cause abnormal wear cylinder liner.
3) Baotou beiben rod bending parts. As a result of the car accident or other reasons, the impact of the connecting rod will produce bending deformation, if not timely correction and continue to use, will accelerate the wear of cylinder liner.Two, measures to reduce the wear of cylinder liner
1 right start and start
Engine cold start, due to low temperature, high viscosity, poor mobility, so that the oil pump oil shortage. At the same time, the original wall of oil in the parking along the cylinder walls dirty, so in the starting moment of lubrication is not the normal work as well, resulting in the starting cylinder wear increase greatly. Therefore, the initial start, should first make the engine idling a few laps to get lubrication friction surface after starting. After starting the heating should be idle, no Meng oil outlet, start again until the oil temperature reached 40 degrees; the start should adhere to hang low gear and sequential each gear driving a mileage, until the temperature is normal, can be turned into normal running.
2 proper selection of lubricating oil
To be in strict accordance with the season and engine performance requirements to choose the best viscosity value of the oil, can not be free to buy and use inferior lubricating oil, and regularly check and maintain the quantity and quality of lubricating oil.
3 to strengthen the maintenance of the filter
The air filter, oil filter and fuel filter to maintain a good working state, to reduce the wear of cylinder liner is essential. Strengthen the “three” maintenance, is to prevent the mechanical impurities into the cylinder, reduce cylinder wear, prolong the service life of the engine is one of the important measures. Some drivers in order to save fuel without air filter is absolutely wrong.
4 keep the engine working temperature
The normal operating temperature of the engine should be at 80-90. The temperature is too low, can’t keep good lubrication, will increase the wear of the cylinder wall, cylinder water vapor condenses into water, acidic gas molecules dissolved in waste gas, formation of acidic substances, so that the cylinder subjected to corrosive wear. Experiments show that when the cylinder temperature from 90 degrees to 50 degrees, cylinder wear for 4 times at 90. Temperature is too high, will reduce the strength of the cylinder and increased wear, and may even lead to excessive expansion of the piston caused by inflated cylinder accident.
5 improve the quality of warranty
In the use of the process, the timely detection of problems in a timely manner to be excluded, at any time to replace or repair damaged and deformed parts. When installing the cylinder liner, it must be checked and assembled strictly according to the technical requirements. In guarantee for ring assignments, to choose the proper elasticity piston ring, tension is too small, so that the gas into the crankcase blow down the walls of the cylinder oil, increasing cylinder wall wear; elastic is too large, directly aggravate the wear of the cylinder walls, or because of the cylinder wall oil film is destroyed and aggravate the wear.
Baotou beiben parts crankshaft and shaft not parallel. Due to the burning of the engine and other reasons, the crankshaft will be subject to severe impact and deformation, if not timely correction and continue to use, will also accelerate the cylinder liner wear.