Structural Modifications of the Inner Surface of Cylinder Liners for Decreasing Mechanical Losses in High-Speed Diesel Engines

The most preferred method for reducing mechanical losses in internal combustion engines (ICEs) is profiling contact surfaces, which involves forming microreliefs on the inner surface of cylinder liners (CLs). This work presents analytical and experimental results of the frictional power losses in the four-stroke diesel engine with smooth and microrelief CLs. The regular microreliefs (RMR), with a groove width of 0.4 mm, an amplitude of 1.5 mm, and a relative frictional area of 8.6%, were formed through vibration rolling. Experiments were conducted on both smooth and microrelief cylinders by measuring fuel consumption at 25–100% nominal load and idle mode at a constant speed. The results showed that compared to the engine with smooth CLs, the total frictional power is reduced by an average of 10.8%, mechanical efficiency is increased by 4.0%, and fuel consumption is decreased by 6.4% for the engine with microrelief cylinders. The measured frictional power dropped by 0.90 kW, which is close to the 0.81 kW value calculated using mathematical models and Ansys software simulation.