What Is A Cylinder Liner And How Does It Work?

One part of the internal combustion engine is the cylinder liner. The crucial duties of shielding the engine block and offering a smooth surface for piston movement fall to the cylinder liner. Engine performance is largely dependent on the kind and substance of cylinder liner used. In this article, MyMROmarts takes customers to discuss cylinder liners' composition, function, and material properties.

 

What Is A Cylinder Liner?

If the inner surface of the cylinder comes into contact with the rapidly moving piston, it may be easily worn down and damaged by high-temperature, high-pressure gas. It is cylindrical elements that make up the engine cylinder liner. By pressing and fixing it in place, the cylinder head presses the cylinder liner into the engine block hole. The engine block and piston are kept apart from direct touch by the cylinder liner's presence. The cylinder block and the cylinder liner's outside surface are completely in touch. The polished inner surface of the cylinder liner makes direct touch with the piston in motion. The cylinder liner's thin metal construction shields the engine's integrity and lessens the wear on the engine block. Dry and wet cylinder liners are the two types of cylinder liners that are most often utilized.

 

Dry Cylinder Liner

Dry cylinder liner is a thin-walled cylinder with a wall thickness of 1-3mm. The characteristic is that the outer surface of the dry cylinder liner is not in direct contact with the cooling water. Dry cylinder liners transfer heat indirectly, so the engine takes longer to cool. Dry cylinder liners rely on the engine block for support. Dry cylinder liners share the forces generated during combustion with the engine block. The advantage of using a dry cylinder liner is that the body has better rigidity and is corrosion-resistant. In addition, dry cylinder liners do not have the problem of cooling water sealing. Typically dry cylinder liners are used in engines where cooling efficiency is not important.

 

Wet Cylinder Liner

The wet cylinder liner is a cylinder with a wall thickness of 5-9mm. The outer wall of the wet cylinder liner is in direct contact with the cooling water. Wet cylinder liners achieve higher combustion temperatures and thermal efficiency. Wet cylinder liners can independently withstand the forces generated during combustion. Heat is transferred directly from the liner to the coolant for efficient heat transfer. The advantage of wet cylinder liners is that wet cylinder liners are relatively easy to remove. Most diesel engines use wet cylinder liners.

 

Cylinder Liner Function

To provide the working area of the cylinder and the required container for fuel combustion, the cylinder liner, cylinder head, and piston work together. The cylinder's cylinder liners serve several vital functions.

 

Provide Sliding Surface

The cylinder liner provides a smooth sliding surface for the piston's reciprocating motion. As the piston reciprocates, the cylinder liner absorbs its side force and serves as the piston's lead. On the cylinder liner's smooth inner wall, there is relatively little friction resistance. The piston moves more smoothly and has less frictional resistance while it is reciprocating thanks to the smooth inner wall.

 

Heat Conduction

The cylinder liner also plays a role in heat conduction. The cylinder liner transfers the heat generated during combustion. The cylinder liner transfers the heat from the piston assembly and itself to the engine block and ultimately to the coolant. The coolant acts as a radiator, allowing the engine to dissipate heat quickly. Keep the engine running normally.

 

Reduce Wear And Tear

Wear brought on by the adhesion of mating components is called abrasion. Both the cylinder liner and the piston that comes into direct touch with it wear less when the cylinder liner is present. The piston would make direct touch with the cylinder block in the absence of a cylinder liner. This situation will result in a significantly higher degree of cylinder block wear. There is a lower replacement cost for the user when there is a cylinder liner present since changing one is less expensive than replacing the complete cylinder block.

 

Cylinder Liner Material

The material selection of the cylinder liner is very critical and directly affects the performance and durability of the engine. Cylinder liners usually use wear-resistant alloy cast iron containing phosphorus or boron as the main material, such as HT25-47, HP-CuCrMo, etc. Alloy cast iron material has excellent performance and can meet the working requirements of the engine under high temperatures and high pressure. In the manufacturing process of cylinder liners, professionals usually use centrifugal casting technology. Starting from the purchased raw materials, the cylinder liner is processed through specific processes. The inner surface of the cylinder liner is often phosphate or coated with chromium to further enhance its performance. The cylinder liner's wear resistance is further increased by chrome plating or phosphate treatment, which also guarantees that the cylinder liner and piston ring are matched. Professionals carefully regulate the cylinder liner's inner surface roughness, which has a certain capacity for storing oil and a running-in performance.

 

When choosing a material, the performance of the cylinder liner may be enhanced by adding elements like silicon, phosphorus, chromium, molybdenum, nickel, copper, vanadium, titanium, and silicon. The hardness and wear resistance of the pad are enhanced by chromium. Wear resistance is increased by molybdenum. Casting quality is enhanced by nickel. Copper is added, which lowers friction and enhances the sliding surface's functionality. Furthermore, the insertion of elements like phosphorous, titanium, and vanadium improves the cylinder liner's metallic structure.