Orthogonal Experiments on Piston Skirt With Groove Structure

XL-2V type engine is used as the research subject. Failure modes of the engine piston and the stress of the working piston that is non-uniform distribution are considered. Many scientists developed the grooves and pits on the surface of kinematic pair, which were uniform distribution and friction reduction and wear-resisting. This paper optimizes the structures of grooves and pits, which are nonuniform distribution, for acclimatizing movement of engine piston. Grooves and through-holes surrounding the piston skirt of the engine is machined, which have variable-depth variable-width variable-separation.The sizes of depth, width and separation are bigger and closer to the top of piston to unload concentrated stress of piston ring grooves and keeping stiffness of piston skirt not to make enlargement deformation.With the orthogonal experiment method, nine test plans are made. The three experimental factors are hole and groove distribution pattern, groove depth, and groove width. Finally a cold test bench of engine is made and research 9 bionic pistons and standard piston are contrasted.Resultsshow that abrasion loss of grooved pistons is redeced 35% and power is enhanced 1%; “grooves distribution”is better than the other two distributions on friction reduction and wear-resisting; the smaller grooves' depth & width, the better piston's rigidity and the longer piston's lifetime are.