Analysis and Modeling of an Electro-Hydro-Mechanical Variable Valve Actuator for Automobile Engines

Abstract

In modern four-stroke automobile engine technology, variable valve timing and lift control offers potential benefits for making a high-performance engine. A novel and simple electro-hydro-mechanical fully variable valve actuator (EHMFVVA) for engine valves is introduced. Just like the conventional mechanical variable valve actuators, a camshaft is still used the design; however, it is employed 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 are also presented. Experimental and simulation results show that the novel electro-hydro-mechanical variable valve actuator can achieve fully variable valve timing and lift control without using complex control systems. Incorporated with the proposed system, the performance of four-stroke engines at different speeds and loads will be significantly increased.