Platform Building And Performance Study Of Diesel Base On Late Intake Valve System

The internal combustion engine has been the most widely used power machinery in agricultural, industrial and transportation, but it brought more challenges to the Energy and Environment when it brought convenience to the human beings. To develop high efficiency, low energy consumption and low emission engine technology is very important while facing the dual pressure brought by Energy shortage and Environmental Pollution. Recent research has been found technology of Variable Valve Timing is the most effective measure to improve the economy and emission of the engine. Valve Timing affects the intake state parameters of the engine, thereby affecting the combustion process of the engine cylinder, resulting in differences of engine performance. The fixed Valve Timing of traditional engine can not guarantee the performance include economy, power and emission in different conditions of the engine, therefore, in order to ensure the engine performance always in the best states, an Electro-Hydraulic Variable Valve System was developed based on a diesel engine, and then establish the test bench so as to study the characteristics of Electro-Hydraulic Variable Valve System.Research on the movement of the additional lift of Electro-Hydraulic Variable Valve System showed both the oil pressure and control pulse can adjust the valve close timing, but the control pulse play a critical role in the valve closing timing, the valve closing timing increase with the control pulse increase; the oil pressure has a little effect on the valve closing timing, the valve closing timing decrease with the oil pressure increase. Both the oil pressure and control pulse can adjust the maximum additional lift(lmax), but the oil pressure play a critical role in lmax, lmax increase with the oil pressure increase; the influence of the control pulse can be analysis in two ways: lmax increase with the control pulse increase while the oil pressure is small, but lmax will keep constant when the control pulse reach a certain value, the additional lift can reach its maximum and lmax keep no change when the oil pressure is big. In addition, stability analysis of lmax indicates the additional lift keep best stability when the oil pressure is 3.0MPa to 4.5MPa.Research on opening and closing characteristic of Electro-Hydraulic Variable Valve System showed the oil pressure has little influence on the opening delay of the additional lift, but it has obvious influence on the closing delay, the closing delay reduce while the oil pressure increase; the control pulse has little influence on both the opening delay and closing delay. In addition, when the oil pressure fixed, the opening duration time of the additional lift will keep linearly increase trend with the increase of the control pulse; when the control pulse fixed, the opening action time of the additional lift will reduce with the increase of the oil pressure, the closing action time of the additional lift will increasing slightly with the increase of the oil pressure.The pressure fluctuation of Electro-Hydraulic Variable Valve System is mainly reflected in five eigenvalues include the first wave peak(A0), the first maintain pressure(B0), the second wave peak(A1), the second maintain pressure(B1) and the third maintain pressure(B2). Study of pressure fluctuation showed the value of A0, B0, A1 and B1 increase with the increase of oil pressure, and B0, A1 and B1 keep linearly growth trend, but what we should attention is that A1 and B1 doesn’t produce when the oil pressure and control pulse is small, and B2 keep no change with the increase of oil pressure. When the oil pressure fixed, the laws of pressure fluctuation are basically the same, the only difference is the control pulse affect the duration of B0, the duration of B0 and B1 increase with the increase of control pulse, the phase time of oil completion release delay with the increase of control pulse. The speed of the camshaft has little effect on the value of A0, B0, A1, B1, B2, but it has obvious influence on the position of A0 and A1 appear, the position of A0 and A1 appear will delay when the speed increase, and the duration of B1 and B2 increase, thereby the phase time of oil completion release will delay, resulting in the delay of the close timing.