The Mechanics Performance Impact Study Of Crankshaft-connecting Rod-piston Under Temperature

Diesel engine is the main power device. Further improvement of its design and manufacture has very important significance to the social development. As parts of the combustion chamber, the working condition of cylinder liner and piston’s system concerns working dependability and use durability of high-speed internal-combustion engine directly. The working environment of cylinder and piston’s system is quite complex, it is influenced not only by mechanical load such as gas pressure, but also by the temperature load caused by the searing gas. Temperature load and mechanical load coupling make piston to produce crackle, piston-ring gluing 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 field that temperature and mechanical load act on together in conformity with the force field, finding out the temperature load state of the piston and comprehensive stress distribution situation, to improve the piston and its working dependability is signification.At the same time, the cylinder liner and piston will generate thermal deformation caused by the temperature load which influenced the fitting clearance of cylinder liner and piston, oil film thickness, the contact force of the piston skirt and cylinder liner etc. Those have a big effect on the secondary motion of piston, which can’t be ignored for the diesel engine noise, vibration and power loss.This text uses the thermocouples to measure the temperature of cylinder liner and makes use of3D graphics software to build up piston and cylinder liner models, which is transmitted into finite element software of ANSYS, to generate finite element model. The text established the reasonable heat exchange boundary conditions according to the temperature field data which was measured and obtained the temperature field of piston and cylinder liner. The text got the stress of the piston under temperature load and the stess of piston under temperature load and mechanical load. The text compared the effect of the piston by temperature. Used the dynamics simulation software AVL to simulate the secondary motion of piston based on the thermal deformation of piston and cylinder liner and compared the secondary motion of piston under high temperature and normal temperature.