Durability And Test Research Of High Power Diesel Engine Piston

Modern diesel engine is widely applied in transport,truck,engineering machine field. The piston, one of the key components, is facing on the commutative action of thermal and mechanical load. Now, the max firestorm pressure of overseas diesel engine has exceeded 25MPa, while the internal engine has reached 17MPa. At the same time, the thermal load of engine has also constantly increased, the support ability of aluminum piston nearly reaches the highest point. The wicked condition will lead to the fatigue destroy of piston. So at designing phase that research piston fatigue destroys and adopting some way to defend piston from fatigue is very necessary.The main research content of this paper is about the fatigue life of the piston, as follows:First, piston temperature field experiment is performed to realize temperature distribution. In order to improve the test bed performance to simulate the truth crack, the piston thermal fatigue test system is ameliorated. Piston structure is changed to extend piston life. According to the other piston thermal fatigue test and piston design experience the way to reduce piston fatigue crack is referred.Secondly, the firestorm pressure of engine has been tested with combustion analysis system. According to the tested firestorm pressure, several pistons bore mechanical pulse fatigue tests are performed with "Piston Pulse Mechanical Fatigue Test System", and the best project of test is selected. Used Glide simulation analysis software, crank angle when the max secondly stress is showed is measured. Then the angle between piston axis and connecting rod is calculated. According to the angle, the tested piston is fitted, next, the piston skirt mechanical pulse fatigue test is performed for a new piston. According to others piston mechanical fatigue tests and piston design experience, some methods of reducing piston mechanical fatigue are referred.In addition, a 3D model of the piston is established. Considering piston boundary condition and according to piston temperature field test, the piston temperature gradient is calculated. Based on the temperature gradient of piston, the temperature sensors are distributed on the tested piston and heat temperature can be confirmed. Selected the piston pin hole design projects, used the FEA software and considering piston mechanical pulse fatigue tests, the best project is selected. When examining piston skirt fatigue intensity, the piston fatigue life can be gotten to use FEA technology. Considering piston fatigue destroys, new project is listed to extend piston fatigue life.As an example, Y piston has been studied and talked about for the crack appearance.