Piston ring of heavy truck parts of Baotou North engine is one of the key parts of engine, and its performance influences the performance of engine directly. At the same time, piston rings are vulnerable parts. When piston rings are repaired, piston is usually lifted. Therefore, the time of overhaul or replacement of piston rings is often regarded as the first overhaul period of engines.
In recent years, due to the high speed and strengthening of engine, the working conditions of piston ring become more and more severe, and higher requirements are also put forward for its wear resistance.
Piston ring wear and its influence factors
The abrasion between piston ring and cylinder liner of automobile engine has the following characteristics:
The 1. piston ring is reciprocating motion between the upper and lower stopping points, and the speed changes from static state to about 30m/s, so the amplitude changes repeatedly.
2. when doing reciprocating motion, the pressure of the cylinder varies greatly during the intake, compression, service and exhaust stroke of the working cycle.
3. because of the burning process, the movement of the piston ring is often in high temperature, especially the first gas ring, chemical produced in high temperature and high pressure and combustion products, it is difficult to establish oil film, to achieve full lubrication is more difficult, and often in critical lubrication.
According to the wear mechanism, the piston ring wear can be divided into normal wear, fusion wear, abrasive wear and corrosion wear. But these wear and tear do not appear alone, but exist at the same time, and influence each other. According to wear parts, piston ring wear can be divided into sliding surface wear and upper and lower end wear. Generally speaking, the sliding surface wear is larger than the upper and lower end face, and the sliding surface is mainly wear and abrasive wear. The upper and lower end faces mainly due to the impact and wear caused by reciprocating movement of piston.
Piston ring sliding surface of the largest wear often occurs in the cylinder TDC, because it is affected by high temperature gas, damage the oil film, resulting in easy melting conditions, thereby speeding up the piston ring wear. The normal wear and tear, as a matter of fact, involves slight wear and abrasive wear. The ring sliding surface wear is the same, the first gas ring wear is the largest, second ring around the first half of the oil ring wear, the school for example, the WD615 engine piston ring after 500h reliability test, the first gas ring gap wear is 0.4 ~ 0.6mm, the second word gap wear is 0.25 ~ 0.4mm, the oil ring gap wear is 0.3 ~ 0.55mm. But sometimes the ring wear is greater than the ring in the middle, which is due to the influence of the oil distribution on the cylinder surface and the adsorption of impurities.
Baotou beiben heavy truck parts on the lower end of the piston ring wear is mainly because the mechanical grinding oil fuel of rigid residue and from the atmosphere into the dust particles formed on the lower end, is the essence of abrasive wear. However, when the abnormal thermal deformation of the piston and the side gap of the ring groove become smaller, welding wear may occur.
Baotou beiben heavy truck parts piston ring wear factors, including piston ring material and shape, cylinder piston material and structure, lubrication and engine structure, operating conditions, fuel oil and lubricating oil quality is the main factor. Of course, in the same cylinder, the influence of lubrication state on the piston ring wear is the largest. The ideal torus between lubrication for two sliding surface with a uniform layer of oil film, but this fact does not exist, especially the first gas ring, due to high temperature, it is difficult to establish ideal lubrication state.
Measures for reducing wear of piston ring
There are many factors that affect the piston ring wear, and these factors are often intertwined. In addition, the type of engine and the use of different conditions, the piston ring wear also have very big difference, thus not only by improving the structure of piston ring and the material itself to solve the problem, mainly to begin from the following aspects: piston ring and cylinder sleeve material and good matching; surface treatment; structure; lubrication oil and additive; because the assembly and the operation of heating in cylinder sleeve and piston deformation etc..