Reasons for cylinder liner wear the working environment of the cylinder liner is very harsh, and there are many reasons for wear. Normal wear is usually allowed for structural reasons, but improper use and maintenance can result in abnormal wear such as abrasive wear, weld wear, and corrosion wear.
1. Wear caused by structural reasons
Poor lubrication condition makes the upper part of the cylinder wear seriously
The upper part of the cylinder liner is close to the combustion chamber. The erosion and dilution of fresh air and unevaporated fuel aggravate the deterioration of upper conditions, which are in dry friction or semi-dry friction at the beginning of the period, which is the cause of severe wear on the upper part of the cylinder.
Acid working environment leads to chemical corrosion, so that the cylinder liner surface corrosion peeling
After the combustible mixture in the cylinder is burned, steam and acid oxides are produced, which dissolve in the water to form mineral acids. In addition, organic acids are generated in the combustion, so that the cylinder liner always works in an acidic environment and produces a corrosive effect on the cylinder surface. The corrosion is gradually scraped off by the piston ring in the friction, resulting in the deformation of the cylinder liner.
Objective reasons lead to mechanical impurities in the cylinder, which aggravate the wear of the cylinder liner
Because of the principle and working environment of the engine, dust in the air and impurities in the lubricating oil enter the cylinder, causing abrasive wear between the piston and the cylinder wall. Dust or impurities with the piston in the cylinder reciprocating motion, as part of the cylinder 臵 speed of movement of the largest, therefore, intensified in central cylinder wear.
Wear and tear caused by failure to use
1. Low filtration efficiency of air filter.
The role of the air filter is to remove the combustible mixture into the cylinder containing dust and sand, in order to reduce the cylinder, piston and piston rings and other parts of the wear. Air filter can not be cleaned and maintained for a long time, poor filtering effect, will accelerate the wear of cylinder liner. The experiment shows that without air filter in the engine, the wear of cylinder will increase by 6-8 times.
2, long time low temperature operation start long time low temperature operation
First, it causes bad combustion and produces carbon deposition, which spreads from the upper part of the cylinder liner and causes serious abrasive wear on the upper part of the cylinder liner during the reciprocating movement of the piston.
Second, is the cause of electrochemical corrosion wear. Due to the low temperature of the engine, the combustible mixture entering the cylinder cannot be fully mixed and burned. On the contrary, part of the fuel and exhaust gas after combustion will stick to the inner wall of the cylinder liner, forming acid corrosion on the inner wall of the cylinder liner.
3, not according to the specified time or mileage for maintenance of engine oil after a certain period of time
Engine oil usually goes black and loses its proper lubrication. Therefore, the engine oil must be replaced after the specified time and mileage. The failure of lubricating oil filter and air filter due to long-term use will not be able to filter the heavy impurities, dust and gravel in lubricating oil and air well, resulting in serious wear and tear of cylinder liner.
Wear and tear caused by improper maintenance
1. Improper installation position of cylinder liner when installing cylinder liner, if there is installation error, the cylinder center line and crankshaft axis are not vertical, which will cause abnormal wear of cylinder liner.
The center line of piston pin is not parallel to the center line of connecting rod head, which forces the piston to tilt to one side of the cylinder liner and also causes abnormal wear of the cylinder liner.
Measures to reduce cylinder liner wear
Correct starting and starting when the engine starts cold
Due to low temperature, oil viscosity, poor liquidity, oil pump supply shortage. At the same time, the oil on the original cylinder wall flows down the cylinder wall after parking. Therefore, it cannot be lubricated as well as it would be in normal work at the moment of starting, which greatly increases the wear of cylinder wall during starting. Therefore, when starting for the first time, the engine should be idled for several turns, and start again after the friction surface is lubricated. Should be idle running after starting to heat up, it is strictly prohibited to fierce boom oil mouth, to start again when the oil temperature of 40 ℃; Start should stick to low gear, and step by step each gear driving a range, until the oil temperature is normal, can be converted to normal driving.
Two, the correct choice of lubricating oil
According to the season and engine performance requirements to choose the best viscosity value of lubricating oil; Do not buy and use inferior lubricants, and often check and maintain the quantity and quality of lubricants.
Three, strengthen the maintenance of the filter to make the air filter
Oil filters and fuel filters are essential to reduce wear and tear on the cylinder liner. Strengthening the maintenance of "three filters" is an important measure to prevent mechanical impurities into the cylinder, reduce cylinder wear, extend the service life of the engine, especially important in rural areas and dusty areas. It is absolutely wrong that some drivers do not install air filters in order to save fuel.
4. Maintain the normal operating temperature of the engine
The normal work of the engine temperature should be at 80-90 ℃. The temperature is too low to maintain good lubrication, which will increase the wear of the cylinder wall. The steam in the cylinder is easy to condense into water droplets, dissolve the acidic gas molecules in the exhaust gas, and generate acidic substances, so that the cylinder wall is corroded and worn. Tests show that when the cylinder wall temperature from 90 ℃ to 50 ℃, the cylinder wear volume for 90 ℃. If the temperature is too high, the cylinder strength will be reduced and the wear will be intensified.