Bore Polishing Wear in Diesel Engine Cylinders

The rate of wear of the cylinder liner is mainly a function of peak cylinder pressure, the depth of penetration of hard carbon particles ingress during abusive running conditions. The problem of wear becomes severe as the blowby past the rings and the oil consumption of an engine increases in diesel engines. In this paper, a methodology is developed to estimate the wear of liner due to bore polishing action. The wear rate is correlated with the product of gaseous load, contact stress, and sliding action of the piston surfaces. Under abnormal conditions, the shear strain due to friction exceeds the plasticity limit of the material, superficial delamination occurs at the liner surfaces. The wear model was validated on large engines running on heavy fuel at 22-bar bmep. The case study results showed that by modifying the piston profile and liner geometry, and bore polishing of the liner surfaces is reduced and the engine oil consumption rate is improved substantially.