DYNAMIC MODEL AND SIMULATION OF A NOVEL ELECTRO-HYDRAULIC FULLY VARIABLE VALVE SYSTEM FOR FOUR-STROKE AUTOMOTIVE ENGINES

In modem four-stroke engine technology, variable valve timing and lift control offers potential benefits for making a high-performance engine. A novel electro-hydraulic fully variable valve train for four-stroke automotive engines is introduced. The construction of the nonlinear mathematic model of the valve train system and its dynamic analysis are also presented. Experimental and simulation results show that the novel electro-hydraulic valve train can achieve fully variable valve timing and lift control. Consequently the engine performance on different loads and speeds will be significantly increased. The technology also permits the elimination of the traditional throttle valve in the gasoline engines and increases engine design flexibility.

Application of Three-Dimensional Visual Simulation in Tidal Defense Engineering

Any tidal defense engineering involves the collection and analysis of massive information about engineering structures and their surrounding environment. Traditional method, which is carried out mainly by means of twodimensional drawings and textures, is not efficient and intuitive enough to analyze the whole project and reflect its spatial relationship. Three-dimensional visual simulation provides an advanced technical means of solving this problem. In this paper, triangular irregular network (TIN) model simplified by non-uniform rational B-splines (NURBS) technique was used to establish the digital terrain model (DTM) of a super large region. Simulation of dynamic water surface was realized by combining noise function with sine wave superposition method. Models of different objects were established with different modeling techniques according to their characteristics. Application of texture mapping technology remarkably improved the authenticity of the models. Taking the tidal defense engineering in the new coastal region of Tianjin as a case study, three-dimensional visual simulation and dynamic roaming of the study area were realized, providing visual analysis and visible demonstration method for the management and emergency decision-making associated with construction.

Mathematical modeling and analysis of thermodynamic processes in a twin-rotor piston engine

In order to study the major performance indicators of the twin-rotor piston engine(TRPE), Matlab/simulink was used to simulate the mathematical models of its thermodynamic processes. With consideration of the characteristics of the working processes in the TRPE, corresponding differential equations were established and then simplified by period features of the TRPE. Finally, the major boundary conditions were figured out. The changing trends of mass, pressure and temperature of working fuel in the working chamber during a complete engine cycle were presented. The simulation results are consistent with the trends of an actual working cycle in the TRPE, which indicates that the method of simulation is feasible. As the pressure in the working chamber is calculated, all the performance parameters of the TRPE can be obtained. The major performance indicators, such as the indicated mean effective pressure, power to weight ratio and the volume power, are also acquired. Compared with three different types of conventional engines, the TRPE has a bigger utilization ratio of cylinder volume, a higher power to weight ratio and a more compact structure. This indicates that TRPE is superior to conventional engines.

INDUSTRIAL ENGINEERING AND VISUALISATION—A PRODUCT DEVELOPMENT PERSPECTIVE

Taking the actual project of teaching and researching process for example, the relationship between the industrial engineering and product development is discussed. And use the novel visualization technology to support the industrial engineering and product development. How to use the new computer modeling and simulating technologies to support the product development and industrial engineering, is introduced especially. The support includes both domestic products and industrial systems. The visualization and computer technologies take a very impo[tant role in some system or multi-direction modeling, those technologies mentioned above can help the industrial engineers study the effect of design on the whole life circle, including the producing steps. So the engineers can avoid making the wrong decision which may cause bad effects on the whole industrial engineering.