What is Cylinder Liner? | What are the types of the Cylinder Liner?

The engine is one of the most important parts of the vehicle. It produces power to run the vehicle. The vehicle engine consists of different parts. The cylinder liner is a most important part of the engine. It is also known as a cylinder sleeve. It ensures the smooth running of the piston. This article mainly explains the various aspects of the cylinder liner.

What is Cylinder Liner?

The cylinder liner is a sleeve placed on the engine block bore to create a cylindrical design. The engine piston moves back and forth in the cylinder liner. It is a vital part of the vehicle that makes up a smooth internal side of the engine.

cylinder liner

Cylinder liners are commonly used on engines with aluminum alloy engine blocks. This is because the aluminum alloy engine block without a liner has poor wear resistance and may warp at high temperatures. Therefore, linear is used for a better surface that can bear high temperatures and pressures.

The life cycle of the cylinder between its re-bores varies according to the following factors:

  • Corrosion
  • Abrasion

The abrasion is highly dependent on the atmospheric conditions and the efficiency of the oil and air filters. Dusty air is very dangerous because it increases cylinder wear.

The corrosive products produced after the combustion of the air-fuel mixture cause cylinder corrosion.

Acidic moisture on the cylinder wall also accelerates corrosion at low temperatures. The cylinder liners increase the service life of the engine cylinder.  

High-quality materials are used for the construction of the liners. You can easily remove and replace the liner.

The cylinder liner must have excellent wear resistance and the capability to hold oil to lubricate the surface between the piston ring and the wall.

Function of Cylinder Liner

The cylinder liner is one of the most important parts of the piston pump or engine. It is an area in which the piston moves. The main function of the cylinder liner is to reduce leakage and provide a smooth sliding surface and space for coolant heat transfer.

function of cylinder liner

The cylinder liner has a cylindrical shape. It is made from a special iron alloy comprising chromium, nickel, manganese, and silicon.

1) Sliding surface

One of the main functions of the cylinder liner is to provide a sliding surface for the motion of the piston. It acts as the internal wall of the cylinder. It traps the lubricant. The cylinder liner has the following major features:  

  1. Outstanding wear resistance
  2. Less wear on the cylinder liner itself
  3. Low lubricant consumption
  4. Less wear on the opposing piston ring

2) Assist to transfer heat

The wet liner transfers heat to the coolant to reduce the engine temperature up to the optimal operating temperature, and the dry liner transfers heat directly to the engine block.

3) Provide Excellent Sealing

The liner has a smooth surface. Therefore, when it makes contact with the piston ring, it provides excellent sealing and lessens the gas leak in compression and exhaust gases.

4) Withstands the Combustion

The cylinder liner has the ability to bear high temperatures and pressures during combustion, so the engine block is not heavily stressed.

5) A liner serves wear and tear to prevent the cylinder block from damage.

Read More: Different types of Engines

Types of Cylinder Liners

The cylinder liner has the following types:

  1. Dry liner
  2. Wet liner
  3. Finned cylinder liner

1) Dry Liner

This type of cylinder liner has a shape like a barrel. It has a flange installed at the top. This flange holds the liner in a similar position to the engine block. These liners don’t have direct contact with the cooling water.

Dry Liner

The socket sits exactly in the cylinder. A precise contact between the socket and block is required for efficient cooling of the cylinder socket.  

In addition, the impact loading, piston thrust, and gas pressure during air-fuel mixture combustion are opposed through the full thickness of the cylinder and socket.

That’s why, the dry liner is thinner. The range of the dry liner wall thickness is from 1.5mm to 3mm and is mainly used to repair worn linings.

2) Wet Liner

In the wet liner, the liner makes contact with the cooling water or coolant. There is a flange on top of the liner that fits into the groove in the cylinder block.

Wet liner

The lower edge of the wet liner is sealed by using a packing ring or sealing ring to prevent cooled water from leaking into the crankcase.

When the wet liner faces the shear, gas pressure, and impact loads, the liner wall thickness increases. Therefore, the wet liner has a greater thickness than the wall thickness of the dry liner.

The wet liner has a wall thickness between 3mm and 6mm. The aluminum is used to coat the external side of the liner. This coating is compulsory to prevent rust.

Wet liners are more cooled than dry liners. It can be easily removed if worn or damaged.

3) Finned Cylinder Liners

The finned cylinder liner has a very similar working to the dry liner, but it has sockets around the outer surface to help with heat dissipation.

Heat and dirt resistant metals are usually utilized in the manufacture of finned liners. These types of liners are mainly designed for air-cooled engines. It is equipped with small fins that suck in the incoming air with great force to cool the cylinder efficiently.

Read More: Working and function of Engine Cycline Block

Cylinder Liner Construction Material

The cylinder liner is most commonly made of nickel-chromium.

The nickel-chromium iron has the following elements:

  1. Chromium 0.7%
  2. Nickel 2%
  3. Silicon 2%
  4. Carbon 3.5%
  5. Sulfur 0.05%
  6. Manganese 0.6%
  7. Phosphorous 1.5%

To improve wear resistance, the liner is stabilized by heating at 855°C to 865°C for 30 to 40 minutes and then oil quenched.

Comparison between Dry Liner and Wet Liner

  1. The cylinder block with a dry liner is stronger than the wet liner.
  2. The wet liner wall has more thickness than the dry liner wall.
  3. Wet liners can be trimmed before installation, but dry liners must be trimmed after installation.
  4. The dry liners don’t make direct contact with the refrigerant but protect the piston from wear and contamination. However, the wet liners make direct contact with the coolant.
  5. Wet liners don’t need to be trimmed accurately on the outside, but dry siding must be trimmed accurately.
  6. The dry liners install directly against the block cooling jacket wall.
  7. The wet liners don’t need special tools for installation and replacement.
  8. Wet liners have easy installation.
  9. Wet cylinder liners require a leak-proof seal to prevent cooling water from entering the crankcase, but dry cylinder liners do not need a leak-proof seal.
  10. The wet liners make direct contact with the coolant and are therefore adequately cooled, while the dry liner is not in direct contact with the coolant. Therefore, the dry liner has a higher operating temperature than the operating temperature of the wet liner.

FAQ Section

What is the function of the cylinder liner?

The main function of the cylinder liner is to reduce leakage and provides a sliding surface for the piston ring.  The engine piston moves inside the liner.

What are the types of the cylinder liners?

The cylinder liners have the following major types:

  1. Dry liner
  2. Finned liner
  3. Wet liner

What is cylinder liner in ship?

The cylinder liner is a cylindrical component installed into the engine block to form a cylinder. It plays a big role to form the interior of the engine.

Read More
  1. Different types of Engines
  2. Types of Internal Combustion Engines
  3. Working and types of Crankshaft 
  4. Function of Engine Valves
  5. Purpose and working of Heat Sink

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