Optimized Design Of The 280/285 Steel Crown Aluminum Skirt Composite Piston On Diesel Engine

The piston, as one of the key spare parts of the internal-combustion engine, its working condition concerns working dependability and use durability of high-speed internal-combustion engine directly, influences the emission performance of the internal-combustion engine directly at the same time. The structure of piston and its working environment are very complicated. In working condition, the piston stands periodic load, such as high gas-pressure, inertia-pressure, side direction pressure and frictional force, which produced by combustion gas pressure strength and high speed reciprocating, and produces mechanical stress and distortion. The burn of high pressure gas produced high temperature distribution is asymmetry, causing the piston to produce hot stress and hot distortion. Hot load and mechanical load coupling make piston to produce crackle, piston ring glued and scuffing of cylinder bore and so on. So during the course of designing, calculating and analyzing the piston temperature field, force field and coupling load that hot and mechanical load act on together in conformity with the force field, finding out the hot load state of the piston and comprehensive stress distribution situation. So to improve the piston and its working dependability is significant.Focusing on part of this field, this paper demonstrates the 3 Dimensions simulation research on the 1/4 and 1/2 models of 280/285 pistons, pins, connecting-rod and cylinder liner coupling. The main content is as below:1. It discusses the current situation of the finite element analysis on internal combustion, demonstrates the technology and validity of the integrated coupling method in detail and also brings forward the intending study points2. With the finite element theory, the paper demonstrates the relative methods of the finite element theory and conventional fatigue stress design method used on the 1/4 and 1/2 models. These researches establish the theoretic foundation of the finite element and fatigue analysis.3. The 1/4 piston integrated assembled model is built. Taking pistons, pins, and connecting - rod (small end) as a system to conduct the calculating analysis, according to the conventional fatigue design method to analyze and select the preferable method and meantime set up the reasonable calculation, finally, it provides optimized aspect for this kind of piston.4. Based on analysis of the 1/4 piston model, it builds the 1/2 integrated piston model of the original plan and optimized plan, and takes pistons, pins, connecting-rod (small end) and the piston bush as a system to analyze. Fully considering the load on the piston, it evaluates the stress and fatigue of the original plan and the optimized plan, comparing with the calculating result of the 1/4 piston model, it selects the best plan.