The bimetallic cylinder liner and engine piston are a pair of friction pairs that operate under conditions of high temperature, high pressure, alternating loads, and corrosion. The conclusion of long-term work in complex situations is that it leads to wear and deformation of bimetallic cylinder liners, which endangers the driving force, rationality, and service life of the engine. Careful analysis of the causes of wear and deformation of bimetallic cylinder liners is of crucial practical significance for improving the rationality of engine applications.

1、 The fundamental reason for the wear of bimetallic cylinder liners is the extreme office environment, and there are many factors that can cause wear. Normally, normal wear and tear is allowed due to structural reasons, but improper application and maintenance can lead to abnormal wear and tear.

1. Wear caused by structural reasons

1) The lubrication condition is not very good, causing severe wear on the upper part of the bimetallic cylinder liner. The adjacent engine combustion chamber above the bimetallic cylinder liner has a high temperature and poor lubrication standards. The fresh air and non-volatile natural material flushing and dilution solution exacerbate the deterioration of the upper standard, causing dry friction or air drying friction on the bimetallic cylinder liner, which is also the reason for the more severe wear on the upper part of the bimetallic cylinder liner.

2) The upper bearing capacity is high, causing the wear of the bimetallic cylinder liner to be heavier at the top and lighter at the bottom. The engine piston is tightly pressed against the cylinder wall under its own elasticity and back pressure effect. The greater the positive pressure, the more difficult it is to generate and maintain a lubricating oil film, and mechanical equipment wear intensifies. In the arrangement of the work stroke, as the piston rod slides down, the positive pressure gradually decreases, so the wear of the bimetallic cylinder liner is heavier at the top and lighter at the bottom.

3) Mineral acids and organic matter corrode and peel off the surface of the bimetallic cylinder liner. After the flammable mixed gas inside the bimetallic cylinder liner ignites, it causes water vapor and acidic oxides, which dissolve in water and convert into mineral acids. In addition, the organic matter generated during ignition has a corrosive effect on the surface of the bimetallic cylinder liner. The corrosive substances are gradually scraped off by the engine piston during friction, causing deformation of the bimetallic cylinder liner.

4) Entering the residue of mechanical equipment exacerbates the wear in the middle of the bimetallic cylinder liner. Dust in the air, residue in lubricating oil, etc. enter between the piston rod and cylinder wall, causing wear of wear-resistant materials. When dust or residue repeatedly moves with the piston rod in the bimetallic cylinder liner, the wear in the middle of the bimetallic cylinder liner is exacerbated due to the operating speed A in the middle of the bimetallic cylinder liner.

2. Wear and tear caused by incorrect operation

1) The actual effect of the lubricating oil filter and air filter is poor. If the lubricating oil filter element works abnormally, the lubricating oil cannot be properly filtered, and the lubricating oil with many hard particles will inevitably increase the wear of the inner wall of the bimetallic cylinder liner.

2) The air filter has a low filtration rate. The function of an air filter is to eliminate dust and small stones from the air entering the bimetallic cylinder liner, in order to reduce wear on components such as the bimetallic cylinder liner, piston rod, and crankshaft. Experiments have shown that if the engine is not equipped with an air filter, the wear of the bimetallic cylinder liner will increase by 6-8 times. The long-term inability to clean and maintain the air filter element will result in poor actual performance and accelerate the wear of the bimetallic cylinder liner.

3) Long term ultra-low temperature operation. Long term ultra-low temperature operation leads to poor ignition and gradual diffusion of carbon deposits from above the bimetallic cylinder liner, causing significant wear of wear-resistant materials above the bimetallic cylinder liner; The second is to cause electrochemical reactions.

4) Often using fake and inferior lubricants. Some car buyers, for the sake of convenience and cost-effectiveness, often purchase fake and inferior lubricating oil from small roadside shops or illegal oil vendors, resulting in significant corrosion on the top of the cylinder liner, and the wear amount is 1-2 times greater than the standard value.

3. Wear and tear caused by unreasonable maintenance

1) The installation position of the bimetallic cylinder liner is unreasonable. When installing the bimetallic cylinder liner, if there is an installation deviation and the axis of the bimetallic cylinder liner is not perpendicular to the centerline of the engine crankshaft, it will cause abnormal wear of the bimetallic cylinder liner.

2) The crankshaft sleeve hole is inclined. During maintenance, when reaming the crankshaft small head shaft sleeve, the cutter may tilt, causing the crankshaft shaft sleeve hole to tilt. The cylinder liner axis and the crankshaft small head axis are not parallel, driving the piston rod to tilt towards one side of the bimetallic cylinder liner, which can also cause abnormal wear of the bimetallic cylinder liner. 3) Bending deformation of crankshaft. Due to QQ flight safety accidents or other reasons, the crankshaft that is impacted can cause bending deformation. If not calibrated immediately and reused, it will also accelerate the wear of the bimetallic cylinder liner.

3) The crankshaft, connecting rod, motor shaft, and machine tool spindle neck have non parallel surfaces. Due to factors such as tile burning, the engine crankshaft may deform under strong influence. If not calibrated immediately and reused, it will also accelerate the wear of the bimetallic cylinder liner.

2、 Countermeasures to alleviate wear of bimetallic cylinder liners: 1. Proper starting and development of the engine. When starting the engine in a cool state, due to low temperature, high viscosity, and poor circulation, the oil provided by the fuel injection pump is insufficient. At the same time, the car oil on the inner wall of the original bimetallic cylinder liner becomes coarse along the bimetallic cylinder liner wall after parking, so it cannot obtain the same excellent lubrication as during normal operation at the moment of starting, resulting in greatly increased wear of the bimetallic cylinder liner wall during starting.

Therefore, during the next start-up, the engine should be revved at high speed for two revolutions, and the friction surface should be moistened before starting. After starting, wait for the engine to run at high speed to increase the temperature. Do not forcefully blow the oil hole until the oil temperature reaches 40 ℃ before proceeding; At the beginning, you should persistently shift into low gear and drive for a certain distance in each gear in sequence until the water temperature is normal, and then it will become normal driving.

4) The appropriate use of lubricating oil should be strictly based on the season and engine characteristics. Lubricating oil with viscosity value A should be used, and fake and inferior lubricating oil should not be purchased casually. The quantity and quality of lubricating oil should be regularly checked and maintained.

5) Strengthening the maintenance of filter elements is particularly important for maintaining stable operation of air filters, oil filters, and gasoline filters, in order to alleviate the wear of bimetallic cylinder liners. Strengthening the maintenance of the "three filters" is a key measure to prevent mechanical equipment residues from entering the bimetallic cylinder liner, alleviate wear and tear of the bimetallic cylinder liner, and increase the service life of the engine. It is crucial in rural and dusty areas. It is incorrect for some drivers to not install air filters in order to better save natural materials.

6) Maintain all normal operating temperatures of the engine. The regular operating temperature of the engine should be between 80-90 ℃. If the temperature is too low, stable lubrication cannot be maintained, which will increase the wear of the bimetallic cylinder liner wall. The water vapor inside the bimetallic cylinder liner is prone to condense into water mist, melting the molecular structure of acidic gases in organic waste gas and converting them into acidic substances, causing corrosion and wear of the bimetallic cylinder liner wall. Experiments have shown that when the temperature of the bimetallic cylinder liner drops from 90 ℃ to 50 ℃, the wear of the bimetallic cylinder liner is four times that of 90 ℃. Excessive temperature can reduce the compressive strength of the bimetallic cylinder liner, exacerbate wear, and even potentially cause excessive expansion of the piston rod, leading to "cylinder expansion" safety accidents.

7) Improve the quality of quality assurance throughout the application process, promptly address issues and promptly remove them, and replace or repair damaged and deformed spare parts anytime, anywhere. When installing the bimetallic cylinder liner, it is necessary to strictly follow the technical standards for inspection and installation. In the warranty replacement work, it is necessary to use engine pistons with moderate elasticity. If the elasticity is too small, natural gas will enter the crankcase and blow off the car oil on the inner wall of the bimetallic cylinder liner, which will increase the wear of the bimetallic cylinder liner wall; Excessive elasticity immediately exacerbates the wear of the bimetallic cylinder liner wall, or exacerbates its wear due to the damage of the floating oil on the inner wall of the bimetallic cylinder liner.