What is a cylinder liner?
It is a cylinder that is fitted to the engine block to form the cylinder, and is one critical function part that forms the engine interior.
In Japan they are usually called Cylinder Liners, but some countries (companies) call them Cylinder Sleeves.
3 functions of Cylinder Liners
Function 1 Form the sliding surface
The cylinder liner forms the sliding surface for the piston and piston rings as the inner wall of the engine. The most crucial function of the cylinder liner is to possess superior characteristics as a sliding surface, and the following four points are extremely important.
- High burn resistance
- Low self-friction
- Low friction with the piston ring
- Low lubricating oil consumption
Function 2 Heat
Reduces vale and cylinder head friction at the same time.
Function 3 Keep airtightness
Prevent compressed gas and combustion gas leaking out. The liner should not be prone to deformation due to the high pressure/high temperature inside the cylinder.
The engine's cylinder wall is high temperature/high pressure, and the piston ring/piston is sliding at high speed, and particularly with truck/bus engines a long-life is demanded, so we use highly friction resistant casting material Cylinder Liners only for cylinders.In addition, to reduce engine weight, engine blocks have changed from cast iron to aluminum alloys. However, because the sliding surfaces on the inner circumference of the cylinders require wear resistance and resistance to deformation during operation, aluminum die-cast blocks with cast-in cast-iron cylinder liners are widely used.