Design And Research On Electronically Controlled Hydraulically Actuating Variable Valve Timing And Lift System

Traditional engine's cam valve timing is fixed and the valve timing is determined through varied valve timing experiments with consideration of others operation conditions. Because it's valve timing is fixed and can not adjust during working condition. Therefore engine capability is difficult to be the best working condition under varied operation conditions. Along with the request of the fuel economy and lower harmful emissions become more and more strict, the traditional valve system is hardly meet these requests.The system can achieve the adjustment of the valve timing, valve lift, valve open period and other parameters according to the respective operation conditions of ICE. These further lead to the improvement of the ICE performance. This variable valve timing and lift system without cam have been paid much attention as the fast development of electronics technology.This variable valve timing and lift system powered by electronic hydraulic system is one kind of variable valve timing and lift system without cam. By analyzing and comparing several kinds of domestic and international advanced electronically controlled variable valve timing and lift system, a new kind of variable valve timing and lift system is developed in this paper. The system simulation model is established for the variable valve timing and lift system, using Matlab/Simulink software. Then the studies on the main structure parameters of the system, such as piston diameter, spring rigidity of the valve and flow area of electro-magnetic valve, obtained the characteristics of the variable intake valve system, Both the model and this studies speed up the development processes, thus minimizing the number of hardware variations.Based on the design and the simulation, a test is conducted on the cylinder heads of 4102BG diesel with the variable valve timing and lift system, which can provide experimental documents for validation. Test bench includes the hydraulic driving system,variable valve actuator system, and electronic control units system etc. According to the experiment, the control strategy was amended detailedly. As a result, a fast, precise and steady dynamic result as well as a reliable static state was achieved.Finally, the simulation model of the 4102BG diesel has been made with GT-POWER. So that the effect of variable valve timing on diesel performances would be researched.