There are many factors that affect piston ring wear, and these factors are often intertwined. In addition, the type of engine and the use conditions are different, and the wear of the piston ring is also very different. Therefore, the problem cannot be solved by improving the structure and material of the piston ring itself. The following aspects can be started:

1. Choose materials with good matching performance

In terms of reducing wear, as a material for piston rings, it must first have good wear resistance and oil storage. Generally speaking, it must be that the first gas ring wears more than the other rings. Therefore, it is particularly necessary to use materials that are good at keeping the oil film without being damaged. One of the reasons why cast iron with graphite structure is valued is that it has good oil storage and wear resistance.
In order to further improve the wear resistance of the piston ring, different types and contents of alloy elements can be added to the cast iron. For example, the chromium molybdenum copper alloy cast iron ring commonly used in engines now has obvious advantages in terms of wear resistance and oil storage. 
In short, the material used for the piston ring is best to form a reasonable wear-resistant structure of soft matrix and hard phase, so that the piston ring is easy to wear during the initial running-in, and difficult to wear after running-in.
In addition, the material of the cylinder matched with the piston ring also has a great influence on the wear of the piston ring. Generally speaking, the wear is the smallest when the hardness difference of the grinding material is zero. As the hardness difference increases, the wear also increases. However, when selecting materials, it is best to make the piston ring reach the wear limit earlier than the cylinder on the premise that the two parts have the longest life. This is because replacing the piston ring is more economical and easier than replacing the cylinder liner.
For abrasive wear, in addition to considering the hardness, the elastic effect of the piston ring material must also be considered. Materials with strong toughness are difficult to wear and have high wear resistance.

2. Structural shape improvement

For decades, many improvements have been made to the structure of the piston ring at home and abroad, and the effect of changing the first gas ring to a barrel surface ring is the most significant. Because the barrel face ring has a series of advantages, as far as wear is concerned, no matter whether the barrel face ring moves up or down, the lubricating oil can lift the ring by the action of the oil wedge to ensure good lubrication. In addition, the barrel surface ring can also avoid edge load. At present, barrel face rings are commonly used as the first ring in enhanced diesel engines, and barrel face rings are more commonly used in other types of diesel engines.
As for the oil ring, the inner brace coil spring cast iron oil ring, which is now commonly used at home and abroad, has great advantages. This oil ring itself is very flexible and has excellent adaptability to the deformed cylinder liner, so that it can maintain good The lubrication reduces wear.
In order to reduce the wear of the piston ring, the cross-sectional structure of the piston ring group must be reasonably matched to maintain a good seal and lubricating oil film.
In addition, in order to reduce the wear of the piston ring, the structure of the cylinder liner and the piston should be reasonably designed. For example, the cylinder liner of the Steyr WD615 engine adopts a platform net structure. During the running-in process, the contact area between the cylinder liner and the piston ring is reduced. , It can maintain liquid lubrication, and the amount of wear is very small. Moreover, the mesh acts as an oil storage tank and improves the ability of the cylinder liner to retain lubricating oil. Therefore, it is very beneficial to reduce the wear of the piston ring and the cylinder liner. Now the engine generally adopts this kind of cylinder liner structure shape. In order to reduce the wear of the upper and lower end faces of the piston ring, the end faces of the piston ring and the ring groove should maintain a proper clearance to avoid excessive impact load. In addition, inlaying wear-resistant austenitic cast iron liners in the upper ring groove of the piston can also reduce the wear on the upper and lower end faces, but this method does not need to be fully promoted except for special circumstances. Because its craft is more difficult to master, the cost is also higher.

3. Surface treatment

The method that can significantly reduce the wear of the piston ring is to perform surface treatment. There are many surface treatment methods currently used. As far as their functions are concerned, they can be summarized into the following three categories:
Improve surface hardness to reduce abrasive wear. That is, a very hard metal layer is formed on the working surface of the ring, so that the soft cast iron abrasive is not easy to be embedded in the surface, and the wear resistance of the ring is improved. Loose-hole chromium plating is now the most widely used. Not only does the chrome-plated layer have high hardness (HV800～1000), the friction coefficient is very small, and the loose-hole chrome layer has a good oil storage structure, so it can significantly improve the wear resistance of the piston ring. In addition, chromium plating has low cost, good stability, and good performance in most cases. Therefore, the first ring of modern automobile engines all use chrome-plated rings, and almost 100% of the oil rings use chrome-plated rings. Practice has proved that after the piston ring is chrome-plated, not only its own wear is small, but the wear of other piston rings and cylinder liners that are not chrome-plated is also small.
For high-speed or enhanced engines, the piston ring should not only be chromium-plated on the outer surface, but also on the upper and lower end surfaces to reduce end surface wear. It is best to all chrome-plated outer surfaces of all ring groups to reduce the wear of the entire piston ring group.
Improve the oil storage capacity and anti-melting ability of the working surface of the piston ring to prevent melting and wear. The lubricating oil film on the working surface of the piston ring is destroyed at high temperatures and sometimes dry friction is formed. If a layer of surface coating with storage oil and anti-fusion is applied to the surface of the piston ring, it can reduce fusion wear and improve the ring’s performance. Pull cylinder capacity. Molybdenum spraying on the piston ring has extremely high resistance to fusion wear. On the one hand, because the sprayed molybdenum layer is a porous oil storage structure coating; on the other hand, the melting point of molybdenum is relatively high (2630°C), and it can still work effectively under dry friction. In this case, the molybdenum-sprayed ring has a higher resistance to welding than the chrome-plated ring. However, the wear resistance of the molybdenum spray ring is worse than that of the chrome-plated ring. In addition, the cost of the molybdenum spray ring is higher and the structural strength is difficult to stabilize. Therefore, unless molybdenum spraying is necessary, it is best to use chrome plating.
Improve the surface treatment of the initial run-in. This kind of surface treatment is to cover the surface of the piston ring with a layer of suitable soft and elastic fragile material, so that the ring and the protruding part of the cylinder liner contact and accelerate the wear, thereby shortening the running-in period and making the ring enter a stable working state. . Phosphating treatment is currently more commonly used. A phosphating film with soft texture and easy to wear is formed on the surface of the piston ring. Because the phosphating treatment requires simple equipment, convenient operation, low cost, and high efficiency, it is commonly used in the piston ring process of small engines. In addition, tin plating and oxidation treatment can also improve the initial running-in.
In the surface treatment of piston rings, chromium plating and molybdenum spraying are the most commonly used methods. In addition, depending on the engine type, structure, use and working conditions, other surface treatment methods are also used, such as soft nitriding treatment, vulcanization treatment, and ferroferric oxide filling.