Study Of Virtual Prototyping Technology For Automobile Engine

In the product design, structure, the problems of function, manufacture technique and maintenance performance of product should be settled during the prior period of exploitation process. Traditionally, the theoretical analysis and proportional physical models are used and the foregone design experience is consulted to resolve these problems. Because the problems of assembly, manipulation and maintenance always can be discovered only during the anaphase or the start-up period of design, even after a period of use, sometimes the products have to be modified returning to the phase of structure design. Thus, the efficiency of product design process is low with high cost. The reason is that the prior period of product design is short of prototype to test, and practice experience is not enough to avoid the potential defects of design. With the development of modern computer simulation and network communication technology, the rise of virtual design technology will offer the new methods to solve these problems. During the initial stages of design, product model can be established directly in the virtual space (computer space), namely virtual prototyping, and the interactive performance can be tested. So, the defects of product can be discovered and solved in time during the initial design period, and the foresighted decision and optimized project be confirmed. The virtual prototyping technology can simplify the design process of mechanical products, shorten the exploitation cycle, reduce the cost, improve the quality and acquire the innovative mechanism products with optimized performance. In this paper, the theory of virtual design is carried out in power machine with the automobile engine as the object. The primary application of virtual prototyping technology realizes the instructive effect of simulation method to the design of internal-combustion engine. The combination of thermal power theory, computer simulation technology and CAD system forms a kind of design method with high efficiency of power machine. The prototype design and virtual test of engine are completely executed in the three-dimensional visual digital space. The process of prototype design is that parts design and system assembly are completed by parameterized model design software after conditions given. The virtual test includes structure test, thermal test, fluid test and mechanical test. In the structure and thermal test some parts of engine such as piston is analyzed by finite element simulation tool, with the distributing law of stress and fatigue intensity obtained. In the fluid test, working process in the cylinder such as compression process is simulated by hydrodynamic analysis tool, with the law of flow, temperature and pressure field variety obtained. And in the mechanical test, the main dynamic system of engine is simulated by dynamics analysis tool of mechanical system, with the change process of total dynamics parameters obtained during the engine working. The primary application of virtual prototyping technology in the main body of engine design shows that the whole design (includes tests) is feasible and credible, and has instructive value in the future practical design and manufacture. It can be estimated that the traditional physical test method of mechanical system would be greatly replaced with computer digital simulation technology witch developing so rapidly.