Experimental Study of Friction Reduction by Reducing Piston Ring Pre-Load

The prime objective of this study is to check the friction reduction by reducing the tangential load of the piston ring. To examine this experimental study has been carried out under motored engine condition from 500 to 4000 engine speed at the step of 500 rpm at different oil temperatures ranging from 40 °C to 120 °C. 15 W40 oil was used for this study. Standard Strip down approach was followed in accessing the Friction. The whole friction measurement was split in crank train and piston group friction and was measured with base and modified piston ring pack. The modified piston ring pack was having 24% less ring tension as compared to base ring pack. The study was carried out using block, crankshaft & Piston of 100 hp, 1.5 litre, 3 cylinder engine with 92 mm stroke and 83 mm bore. In each test ring pack was tested as a part of complete piston assembly. The result shows a maximum benefit of 6.21% & 4.7% in FMEP in piston group and crank train friction respectively at 90 °C oil temperature and 2000 rpm with modified ring pack over the base ring pack. The Friction benefit observed to be higher at lower rpm which slightly decreased at higher rpm.

The functionality and durability of the modified piston ring was also checked on the engine in terms of blow by, oil consumption and visual observation after the test. The blow by was observed to be comparable with the exiting ring pack and was well below the specified limit of 70 lpm. The Engine oil consumption with modified ring pack was also observed to be comparable with the existing ring pack and was below the design limit of 22 g/hr. No abnormality observed during durability test and during post test analysis of piston and ring pack.