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As per pieces of literature, 40 to 60 % of friction losses of Internal combustion engines occur in their piston-piston rings-liner assemblies and, there is a significant supportive role of simulation in improving this assembly. Literature is also available which tells, how changes in pistons affect oil consumption. Thus, piston dynamics is also important for oil consumption. Furthermore, the results from the simulation module of piston movement also serve as a significant input for postprocessing to calculate piston ring dynamics. This research is conducted to understand the piston secondary motion effect on oil consumption, friction, and blow-by. In this work, the results of ring dynamics and oil consumption simulation modules are studied with consideration and non-consideration of piston secondary motion results. The results like minimum oil film thickness, lubricating oil consumption, friction, friction power loss, and blow-by are investigated.

Global development trend in diesel engine is to extract more power from the same engine thereby increasing the brake mean effective pressure (BMEP). With increase in the engine BMEP, maintaining reliability of the pistons and piston ring set becomes challenging as mechanical and thermal loading increases simultaneously. Reliability can be maintained by changing the material to higher grade and/or applying different coatings; however this involves significant cost and development time. It is always preferred to keep the same material and improve the reliability of parts. In this work the BMEP of a heavy duty medium speed diesel engine is increased by 10% (from 22.8 bar BMEP to 25 bar BMEP) without change in the piston or piston ring set material. This is achieved by studying the effect of existing piston bowl shape and then changing the shape to improve the reliability of piston and piston ring set. A systematic 6 step methodology is followed.

The research work focus on the occurrence of incylinder peak pressure variation and fuel spray characteristics on piston seizure. The study has been carried out for direct injection diesel engine of heavy duty off-highway application. The well optimized and normal combustion results into the peak cylinder pressure variation within 3.5 bar to 4 bar, whereas the abnormal combustion signposts the peak cylinder pressure almost double of normal combustion. The research work has been carried out to study the effect of different peak cylinder pressure variation and its effect on the start of piston seizure. The three different range of peak cylinder pressure variation have been selected for the study. The selected range of peak cylinder pressure depicts normal to abnormal combustion characteristics. The effect on piston motion dynamics and start of piston seizure has been carried out successfully.