A Study On Compositive Piston Ring Of Diesel Engine

In the operation process of diesel locomotive, problems such as "high oil consumption", "severe abrasion of piston ring and piston ring groove" and "short overhaul range" will appear, which are mainly caused by the deficient structure design of the piston ring in the engine. Tubby ring or rectangular ring could not help solve the problems of high oil consumption and severe abrasion of the engine.This paper studies compositive piston ring to solve the technical problems. Design the piston ring 2 of diesel engine into compositive piston ring made up of two rings, with the upper tubby ring and lower taper ring. The compositive piston ring combines advantages of tubby ring and taper ring, and can store a small amount of oil in its oil storage chamber formed between the upper ring and lower ring,which is good for the control of the engine oil on the cylinder cover and the lubrication between the cylinder cover and the piston ring. Therefore, the compositive piston ring has the following advantages: it has good control of oil, prevents oil from entering combustion chamber in the maximum amount while ensuring normal lubrication, reduces oil consumption, and improves the combustion process, reduces combustion chamber coke, thus guarantee reliable and steady operation of diesel engine. Meanwhile, it has good air seal and lubrication capability, reduces sharply the linking air from combustion chamber to crankcase, enhances the work efficiency of diesel engine. Thirdly, the elasticity of each ring of the compositive piston ring decreases and form the even lubrication oil film on the cylinder side, reduces the abrasion value of the piston ring, cylinder cover and piston ring groove and the abrasion power losing of the engine.To check the practical effect of the compositive piston ring designed in this article, the compositive piston rings were equipped on the 4 diesel engines of DF4D of Zhengzhou Railway Bureau to be tested, the total running distance is 850 thousand kilometers. The examining of test locomotive shows that coke in combustion chamber and exhaust passage has been reduced largely, as well as friction consumption between piston ring, piston ring groove and cylinder cover, thus extend its working time. By comparing the two oil consumption values of test locomotive and original locomotive, it is clear that oil consumption is reduced by 1.45 percent, and the economic benefit is remarkable. So, the compositove piston ring will probably promote the technical renews in the diesel engine of the locomotive and have a board market prospect.