Valve Mechanism Development Of Truck Diesel Engine

a truck diesel engine valve mechanism developmentWith the rapid development of Chinese economy, automobile industry also obtained rapid development, Chinese automobile and engine design R & D and manufacturing level is also facing a big test. Design and development staff to more and more pressure, the ability to request more and more high. In order to meet the higher emissions regulations, in order to obtain a higher power output, in order to get better fuel economy, the engine of the system development is becoming more and more critical.This paper 's main work is around how to design to meet future European V environmental protection laws and regulations of the valve mechanism and carrying out. In this paper, the major work:. The concept design stage, in order to obtain a better volumetric efficiency, better combustion, selected a DOHC design, in order to obtain a better valve mechanism durability, selected roller rocker and valve top cap of the valve structure.The layout design stage, using FEV V / ENGINE software CAE simulation analysis, respectively using the kinematics analysis and dynamics analysis of the valve mechanism performance are evaluated. The valve assembly includes the contact force between size, Hertz stress, valve seating velocity, flies off the valve spring pressure and speed, etc.. For the follow-up of the valve mechanism parts design reference. Is focused on the optimization of the intake cam acceleration curve.The detailed design stage, according to the CAE simulation analysis results, the local optimization of the cam profile, based on the cylinder pressure and exhaust brake pressure curve optimization of valve spring design parameters are selected at the same time, cam and rocker arm of the material.The system performance validation phase, in a cylinder mounted on the valve lift rocker cam test sensor and strain gauge, monitoring the crash speed are in a reasonable range, monitoring rocker occur when the fly off or bounce.The system durability validation phase, with the corresponding engine and vehicle successfully passed all tests.The main innovation of the paper: The main innovation is in the valve mechanism kinematics and dynamics analysis for the foundation, added to the motored simulation analysis, a more complete analysis of the valve mechanism in the engine to all conditions of application, more stick into the practical application of;The valve mechanism of development in the past to simulation, simulation analysis based on CAE, the valve mechanism of actual performance through the engine performance whether it meets the requirements for indirect assessment, this paper adds a special valve mechanism of performance test, the actual measuring valve seating velocity, the contact forces between the rocker arm and the cam, and the simulation results compared with CAE, can more accurately grasp the properties of valve mechanism;The design of valve spring of early development considering the exhaust brake effect, design a high stress of engine exhaust valve spring meet special conditions required;...