Cylinder Head Bolts Tightening Strategies Parameters Finalization by Taguchi Method for Multi Cylinder Engines

Abstract

The Cylinder head gasket (CHG) joint is the most important sealing joint for IC engine performance. Cylinder head bolt preload application should be stoichiometric. Excess cylinder head bolt pre-tension develops more stresses and extra bore deformation and insufficient cylinder head bolt pre-tension leads to gasket leakage. Uniform pressure distribution is required on cylinder head gasket but it is not possible because of varying stiffness of the head and block. Hence maximum pressure distribution is better for avoiding the leakages. Bore deformation, engine blow-by and lubricating oil consumption (LOC) of the engine minimum is better for achieving stringent emission norms. Influences of application method of preload, cylinder head bolt tightening pattern and number of passes are investigated on gasket pressure distribution, bore deformation, engine blow-by and LOC. FEA non-linear analysis is carried out for gasket pressure distribution and bore deformation. Piston and piston ring software is used for simulating engine blow-by and LOC. For optimizing controllable parameters Taguchi design of experiments method is used for robust and optimized design. Study reveals that tightening parameters influences are significant. This study is very important for IC engine efficiency improvement and engine CO2 emission reduction at design stage for new engine development program.