| Energy and environment have become the general focus of the world."Energy thrift and environment protection"has also become the slogan of the present age. Automobile is the symbol of human civilization, as well as one of the reasons for energy consumption and environment pollution. In China,with the rapid development of industrialisation and city, the dual pressure of energy and environment becomes more and more serious, in order to suit the steps of the age, we have to design and produce automobile which has high-efficiency and low-pollution.Engine is the power source of automobile, but it is also the source of environment pollution. So the engine experts is exploring some new kinds of methods about controlling and combustion actively. The realization of many ways depends on the accurate control about valve timing which includes opening timing and closing timing. In order to achieve these combustion ways, there must be an appropriate valve mechanism. Cam valve timing in traditional engine is fixed and the valve timing is determined through various valve timing experiments with consideration of others operation condition, so that the potential of engine is not enough to exert because the valve timing is not suit to every operation condition. As to fixed valve timing, variable valve timing(VVT) could give a appropriate valve timing to the whole scope of speed and load, accordingly VVT meet the engine's need and improve its performance wholly. Therefore, VVT is noticed in the study of internal combustion engine, and is essential to be researched in this area.VVT comprises cam and camless systems. Cam system is used in automobile widely, because its mechanism is simple, controlling is easy and reliability is high. However, this kind of system which is developed from traditional system is still based on cam, so there are still some limits in structure. Camless system abandons the traditional cam and its follower, it can drive the valve directly by electromagnetic, electrohydraulic, electric or other ways. This kind of system has an ECU which can receive the operational information and send the control signal to valve, so engines with this system are improved in economy, power ability and emission performance. Now camless system is not used widely because its mechanism, reliability and cost, but it must be the future trend of valve mechanism.In the previous project, we designed and produced a valve train powered by electronic hydraulic system based on ZS1105 without changing its cylinder head and valve springs. We found that valve bounce after arriving the maximum lift during the experiment of the system. Taking valve bounce as the thread, the author simulated and analyzed the system by using the software of AMEsim and ADAMS.First of all, the reason of valve bounce and corresponding factors were studied. The conclusion that the driving force fluctuation and valve spring lead to this phenomenon was done through the simulative results. As to other factors, they have only little effect on valve bounce and are not the main reason .Secondly, many important parameters were studied by changing parameters, which include hydraulic force,hydraulic piston mass,stiffness of valve spring,valve lift,hydraulic pipe,hydraulic oil and accumulator. Moreover, the method of damping chamber was done according to the simulative results. In order to exert the function of damping chamber sufficiently, the author rebuilt the model including damping chamber. The diameter of orifice and the displacement of large hole were confirmed through the new model.Lastly, the mechanism powered by electronic hydraulic was improved by adding damping chamber according to the simulative results. The compare was made between testing lift and simulative lift, the result indicates that the trend of lift is identical. So it is enough to prove that the models built in this paper are precise and the simulative results are useful for the future optimization.
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