Electromechanical valve trains in camless engines enable virtually fully variable valve timing that offers large potential for both part load fuel economy and high low end torque. Based upon the principle of a spring-mass-oscillator, the actuator stores the energy to open and close the valves in springs. However, the motion of the valves and the electromechanical actuation suffers from parasitic losses, such as friction and ohmic resistance. Besides eddy current losses, gas forces obviously play a further important role in the control of exhaust valve opening especially at high engine speeds and loads. Based on engine test bench data, computational simulations (3D CFD, gas exchange process and electromechanical system) are carried out to analyze the effects of exhaust valve gas forces on the dynamic motion of valve and actuator. The modeling approach and results of this investigation are discussed in this paper.
Modeling of Exhaust Valve Opening in a Camless Engine
Sae Technical Papers
SAE 2002 World Congress & Exhibition ; 2002
2002-03-04
Conference paper
English
Modeling of exhaust valve opening on a camless engine
Automotive engineering | 2002
|Automotive engineering | 1996
|SAE Technical Papers | 1996
|Modeling of Variable Intake Valve Timing in Camless Turbocharged Diesel Engine
British Library Conference Proceedings | 2006
|New tech: Renault's camless engine
Online Contents | 1999