Deriving the Optimal Engine Liner Assembly Tolerance through Virtual Simulations 2020-01-5051
Simulation-based engineering is very effective and efficient approach, as it has got shorter development time and corresponding cost associated in program delivery. It also helps in limiting the experimental-based operations and prototype numbers necessary to design a powertrain. Use of finite element method (FEM) enables to assure the structural integrity of the engine head block and also to contribute to better understanding of the system behavior under assembly loads and various operating conditions.
Engine block liner plays an important role in the design of the combustion chamber and defining the size of internal combustion engines. In the service life of the engine, cylinder internal surface will wear out due to the friction and wear pattern is nonuniform. Engine life could be extended with re-boring and using higher size pistons. But it has limitations, after attaining maximum wear limit, re-boring of parent bore will have major impact on the engine performance and block replacement is essential. Therefore, the concept of liner press fitting in the block is introduced, which helps to restore engine performance and reduces the customer cost effectively in the life cycle of engine.
This paper describes the study of precise tolerance specifications of liner block using virtual simulations. Normal strength criteria do not provide the sufficient and necessary information about the complete contact parameters. Tangential stresses and contact slip are generated due to the interaction between the liner and block. These parameters are considered in the current study to predict the cylinder block liner press fit tolerance band. Contact slip decides the lower limit of the tolerance band, while the tangential stresses provide the upper limiting value of the tolerance band of press fitting.