The Kinetic Study Of The Diesel Engine Piston Assembly

Piston-piston ring-liner system are the crucial friction parts of the internal combustion engine, the quality of their performances directly influence the engine power, economy and emission characteristics. The dynamic characteristics of piston components study can make it clear how parameters play their roles and what's the relationship among them.This can be the design basis of optimization piston components.A four-cylinder diesel engine piston components was studied,and then three-dimensional models were established,so that some important parameters were caculated.Parameters such as engine heat transfer coefficient were obtained from AVL Boost,in order that the caculation of the dynamic charecteristics of piston components could be solved.AVL EXCITE Piston & Rings software was then used to analyze the piston components. Some parameters that influence piston secondary motion such as the bump position of piston profile,the offset of piston pin and stiffness of piston were analyzed. Running surfaces of first ring and second ring and stiffness of piston were taken into consideration on oil consumption.And some factors that infulence gas blow-by were analyzed.Research show piston racial displacement reduced 18.2%,and the maxium kinetic energy reduced 44% when the bump position rised 5mm,but the friction loss increased.When the stiffness of piston become higher,it can reduce certain amount of piston secondary motion.In ring's running surface,the Barrel surface degrees and the angle of curve above bump position are the main factors to influence oil consumption.Oil consumption will increase a little when the thickness of scarper blade of second ring are increased,and oil consumption of scraping in piston top edge will increase with piston stiffness becoming higer in certain range.Ring end gap,especially the first ring,can greatly infulence gas blow-by. Simulation status show gas blow-by has reduced 13.1% when first ring end gap reduced 0.1mm.