Design and Modelling of a Novel Electromechanical Fully Variable Valve System

摘要

In a modern four-stroke automotive engine, variable valve technology offers potential benefits for making a high-performance engine. In this paper, a novel electromechanical fully variable valve system (EMFVVS) is introduced. Just like the conventional mechanical variable valve systems, this design still uses a camshaft mechanism, but it is integrated into an electrohydraulic system to form an electromechanical system. The use of electrohydraulic system is to provide input hydraulic pulses to drive the engine valves cyclically. The output valve profile is controlled electronically by a common proportional pressure relief valve, and hence Late-Valve-Opening + Early-Valve-Closing + Variable-Max-Valve-Lift can be achieved. The construction of the mathematical model of the variable valve system and its dynamic analysis, and some design issues are presented in this paper. Experimental and simulation results show that the novel electromechanical variable valve system can achieve fully variable valve timing and lift control without using complex control systems, and has the potential to eliminate the traditional throttle valve in the gasoline engines.