What are the causes of engine cylinder liner wear? How to prevent?

Category:Automobile engine repair - Date:2017-02-22
As we all know, the working environment of cylinder liner is very bad, so wear is unavoidable in long-term work. Normal wear is usually allowed for structural reasons, but improper use and maintenance will result in abnormal wear, such as abrasive wear, melting wear and corrosion wear. Now let's analyze the causes of abnormal wear of engine cylinder sleeves.



The structural causes cause the wear of engine cylinder liner

1. to the upper part of the cylinder wear lubrication condition
the upper part of the cylinder liner is near the combustor with high temperature and the price difference of the lubricating strip. The scour and dilution of fresh air and the non evaporated fuel aggravate the deterioration of the upper conditions, and are at the dry friction or semi dry friction during the period, which is the cause of the serious wear of the upper cylinder.


2. acidic working environment leads to chemical corrosion, so that the cylinder liner surface corrosion and spalling.
After combustion of combustible mixture in the cylinder, water vapor and acid oxides are produced. They are dissolved in water to produce mineral acids, plus organic acids produced in the combustion. The cylinder sleeves are always working in the acid environment, causing corrosion to the cylinder surface, and the corrosion objects are gradually scraped off by the piston rings in the friction and cause the cylinder liner. Deformation.


objective reasons for.3. lead to mechanical impurities in the cylinder and increase the wear of the middle part of the cylinder liner.

Due to the principle of the engine and the working environment, the dust in the air and the impurities in the lubricating oil enter the cylinder, causing abrasive wear between the piston and the cylinder wall. When dust or impurities move back and forth when the piston moves in the cylinder, the movement speed in the cylinder position is the largest, which aggravates the wear in the middle part of the cylinder.


The wear of engine cylinder liner caused by improper use

1. air filter efficiency is low.

the function of the air filter is to remove the dust and sand contained in the combustible mixture into the cylinder, so as to reduce the wear of cylinders, piston rings and other parts. The air cleaner is not a long-term cleaning and maintenance, cleaning effect is poor, the cylinder liner wear will accelerate. The experiment shows that if the air filter is not installed on the engine, the wear of the cylinder will increase by 6-8 times.


2. operates at low temperature for a long time and operates at low temperature for a long time.
One is caused by bad combustion, producing carbon, carbon from the upper part of cylinder liner, and causing serious abrasive wear in the upper cylinder sleeve during the reciprocating movement of the piston;

Two is caused by electrochemical corrosion wear. Because of the low temperature of the engine, the combustible mixture that enters the cylinder can not be fully mixed. Instead, a part of the fuel and the exhaust gas after the combustion will adhere to the inner wall of the cylinder sleeve, forming the acid corrosion of the inner wall of the cylinder sleeve.

3. does not maintain and maintain engine oil in a specified time or mileage.
oil will usually turn black and lose its proper lubrication. Therefore, engine lubricating oil must be replaced after specified time and mileage. The long term use of the lubricating oil filter and air filter causes failure, and it will not filter well the impurities, dust and gravel of the heavy lubricating oil and air, and cause the cylinder liner to wear seriously.

The wear of the cylinder liner caused by improper maintenance
the improper installation position of.1. cylinder sleeve in the installation of cylinder sleeve, if there are installation errors, the central line of the cylinder and the axis of the crankshaft are not vertical, which will cause the cylinder sleeve to wear out of normal wear.

In the repair of 2. connecting rod copper sleeve hole, when reaming the connecting rod small copper sleeve, the reamer tilts the connecting rod copper sleeve hole skew, and the center line of the piston pin is not parallel to the central line of the connecting rod, forcing the piston to tilt to one side of the cylinder sleeve, and it will also cause the cylinder sleeve to be non normal wear.


Measures to prevent the wear of cylinder liner
1. Start and start correctly. When starting the engine, the cold car starts.
because of low temperature, high oil viscosity and poor fluidity, the oil pump is short of oil supply. At the same time, the oil on the cylinder wall will flow down the cylinder wall after parking, so it can not be lubricated as good as normal work at the moment of starting, which greatly increases the wear of the cylinder wall. Therefore, when starting for the first time, the engine should be idled several times before the friction surface is lubricated and then started. After starting, the engine should be run up at idle speed, strictly prohibit the heavy oil port, and then start at the temperature of 40 C. The start should stick to the low speed gear and follow each gear for a period of mileage, until the oil temperature is normal, then it can turn to normal driving.

two. The best viscosity value of lubricating oil must be selected strictly according to season and engine performance requirements.
it is not allowed to purchase low-grade lubricants at random, and check and maintain the quantity and quality of lubricants regularly.

three. Strengthen the maintenance of filters to make air filters. oil filter and fuel filter keep good working condition, which is very important for lighten the wear of cylinder liner.

strengthening the maintenance of "three filters" is an important measure to prevent mechanical impurities from entering the cylinder, lighten the wear of the cylinder and prolong the service life of the engine. It is particularly important in the rural and windy sand areas. Some drivers are absolutely wrong in order to save fuel and do not install air filters.


Four. Keep the normal working temperature of the engine

the normal working temperature of the engine should be at 80-90 C. Low temperature, can not keep good lubrication, will increase the wear of cylinder wall, the water vapor in the cylinder is easily condensed into water, dissolved acid gas molecules in the exhaust gas, and produce acid, so that the cylinder wall is corroded by corrosion. The test shows that when the temperature of the cylinder is reduced from 90 to 50, the wear rate of the cylinder is 4 times that of 90. If the temperature is too high, the strength of the cylinder will be reduced and the wear will be intensified. It may even cause the expansion of the piston and cause the "expansion cylinder" accident.




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