Research On Fully Variable Valve Hydraulic System Of Multi-cylinder Engine

Fully variable valve system (FVVS) can realize the continuous variability of the maximum valve lift, the valve opening duration and the valve timing. So there is an important significance to energy conservation and emission reduction of the engine.The paper chooses the structure of295diesel engine as the alteration object. Through redesigning valve engine, a kind of FVVS driven by valve-train cam is designed and developed, It is called SDFVVS for short in this paper.The intake valve is opened by the hydraulic valve actuator which is set between the camshaft and the intake valve, and it is closed by the reliever which could relieve the oil pressure of the hydraulic system in SDFVVS. The valve-seating velocity is controlled by the valve-seating buffer mechanism. The main work includes the following aspects:Firstly, redesign the cylinder cover, the main function for the hydraulic oil flow space and provide good sealing to establish pressure. Redesign the cylinder block structure of295diesel engine and every subassembly of hydraulic pressure drive variable valve train. Design a tappet, piston, through the CAM, a column, the piston driven into the valve opening process; In order to achieve the buffer when the valve seated, the design of the throttle plate is to achieve reliable and stable intake valve.Secondly, design transmission mechanism, through the control valve opening and closing action to meet the requirements of the valve movement rules and the valve timing by camshaft, Drive mechanism is a transmission of power and the rate of change of institutions, to occupy a major role in the Engine Valve demanding on the transmission, this paper focuses on design of the camshaft gear, controllers and other gear, the accuracy of the power transmission.Finally, the design of hydraulic controls, hydraulic controller controls the oil into the moment of the cylinder body, making the tank filled with hydraulic oil, a medium for power transmission, the initial point of the fluid drain, makes the intake valve in a timely down, so as to achieve intake later than the closing angel continuously variable.Though the above work, the Fully variable valve timing system in the single machine success after the trial, in many of the machine on trial implementation of the cylinder has taken the first step, this for all the Fully variable valve timing research is of great significance, also for the engine in the technical performance of exploration has done a little contribution.