What is cylinder liner?
A cylinder liner is like a sleeve that is fitted into the bore of the cylinder block that provides a smooth surface for the reciprocatory motion of the piston.
The cylinder liner is generally used in engines with the aluminum alloys engine block. These engine blocks without a liner can deform at higher temperatures and also has lower wear resistance. Therefore in such engines, the linear helps to provide a better surface that can withstand high temperature and pressure.
Function of cylinder liner in ic engine:
Some of the major functions of cylinder liners are to provide a smooth sliding surface, reduce leakages, and to provide space for heat transfer by coolants.
The each function of cylinder liners are described below:-
1] Sliding surface for the movement of piston:-
The cylinder liner acts as a reciprocating surface for the piston. The surface of the cylinder liner is smoother, therefore the piston can easily slide inside of the cylinder liner. And thus the cylinder liner requires less amount of lubrication.
Because of the highly finished surface of the liners, the rate of wear of the surfaces of piston rings due to the friction is also reduced.
2] Helps to transfer heat:-
The dry liners transfer heat directly to the engine block while the wet liners transfer heat to the coolant fluid to lower the temperature of the engine to optimum working temperature.
3] Provider better sealing:-
The smooth surfaces of the cylinder liner along with piston rings forms better sealing, thus it reduces the leakage during the compression and the leakage of exhaust gases.
4] It withstands the combustion:-
The cylinder liner withstands high temperature and pressure during the combustion process, therefore the engine block never experiences the higher stresses.
5] The cylinder liner undergoes wear and tear to protect the cylinder block from damages.
Types of cylinder liners:
The cylinder liners are generally of three types:-
1] Dry cylinder liner:- The dry cylinder liner never uses coolants for heat dissipation. These cylinder liners are directly attached to the cylinder blocks. The thickness of these liners is less for better heat transfer.
2] Wet cylinder liners:- The wet cylinder liners have a cooling passage around its outer surface. Therefore it can easily dissipate heat to the coolant fluid. These cylinder liners are thick in size and fitted on cylinder block with gaskets.
3] Finned cylinder liners:- These are also like dry cylinder linear but these liners have fins around its outer surface for easy heat dissipation.