A Continuously Variable Poppet Valve Actuator for Internal Combustion Engines

1986 ◽  
Vol 200 (3) ◽  
pp. 187-195 ◽  
Author(s):  
S J Charlton ◽  
M Shafie-Pour
Keyword(s):  
Internal Combustion Engines ◽  
Internal Combustion ◽  
Combustion Engines ◽  
Finite Element Program ◽  
Rigid Body Dynamic ◽  
Poppet Valve ◽  
Actuation System ◽  
Valve Motion ◽  
Element Program ◽  
Body Dynamic

The paper describes a continuously variable poppet valve actuation system which may be applied to internal combustion engines to render the valve motion controllable while the engine is running. The first phase of a programme to develop the device is described. The results of a rigid-body dynamic analysis are presented followed by a dynamic simulation of the mechanism using a proprietary finite element program. These give an insight into its operation and clarify some of the problems to be solved if the device is to be successfully applied.

Improved Mechanical Design for a Fully Variable Electromechanical Valve Actuation System for Internal Combustion Engines

2010 ◽  
Author(s):  
Hossein Rokni Damavandi Taher ◽  
Rudolf J. Seethaler ◽  
Abbas S. Milani
Keyword(s):  
Internal Combustion Engines ◽  
Mechanical Design ◽  
Experimental Tests ◽  
Internal Combustion ◽  
Combustion Engines ◽  
Mechanical Vibrations ◽  
Actuation System ◽  
Ohmic Losses ◽  
Valve Motion ◽  
Valve Actuation

This study aims to improve the mechanical design of a fully flexible valve actuation system (FFVA) for intake valves of internal combustion engines. Optimization procedures for increasing the reliability and efficiency of the mechanical design of the FFVA system are presented. Simulations and experimental tests are carried out in order to validate the system performance. It is shown that position, velocity and acceleration of the valve obtained by simulations are consistent with those observed experimentally. Furthermore, it is observed that the mechanical vibrations are considerably reduced in the redesigned FFVA system. As a result, current levels and ohmic losses in the electric motor are also reduced. The present redesigned FFVA system then provides more reliable valve motion and better efficiency than the previously shown design [25].

An Optimum Flexible Linkage Design of a Fully Variable Electromechanical Valve Actuation System for Internal Combustion Engines

2011 ◽  
Vol 133 (12) ◽  
Author(s):  
D. T. Hossein Rokni ◽  
Rudolf J. Seethaler ◽  
Abbas S. Milani
Keyword(s):  
Internal Combustion Engines ◽  
Mechanical Design ◽  
Design Procedure ◽  
Experimental Tests ◽  
Internal Combustion ◽  
Combustion Engines ◽  
Connecting Rod ◽  
Actuation System ◽  
Flexible Linkage ◽  
Valve Actuation

In this study, the mechanical design of a fully flexible valve actuation system (FFVA) for intake valves of naturally aspirated internal combustion engines is optimized. The original FFVA design used a connecting rod in order to transform the rotating motion of the actuator to translating motion of the valve. In the improved design introduced here, the connecting rod is replaced by a flexible linkage. This step is taken in order to eliminate wear and play in the mechanical connections. A detailed design procedure is presented to optimize the heavy fatigue load on this element. Simulations and experimental tests are carried out in order to validate the system performance. It is shown that valve trajectory and energy consumption of the actuation system obtained by simulations are consistent with those observed experimentally. The present redesigned FFVA system then provides more reliable valve motion than previously shown designs.

A Cogging Torque Assisted Motor Driven Valve Actuation System for Internal Combustion Engines

2013 ◽  
Author(s):  
Bradley A. Reinholz ◽  
Rudolf J. Seethaler
Keyword(s):  
Internal Combustion Engines ◽  
High Efficiency ◽  
Acoustic Emissions ◽  
Internal Combustion ◽  
Performance Criteria ◽  
Combustion Engines ◽  
Cogging Torque ◽  
Actuation System ◽  
Stringent Performance ◽  
Valve Actuation

Electromechanical valve actuation (EVA) for internal combustion engines promises to significantly improve engine efficiency and lower emissions by reducing pumping losses and allowing for novel combustion strategies. However, current designs have not been able to meet the stringent performance criteria for reliability, efficiency, acoustic emissions, weight, and cost that are required by the automotive industry. This paper describes a novel cogging torque assisted motor driven (CTAMD) valve actuation system that promises to meet both the performance and robustness requirements. In contrary to existing EVA systems that recover the kinetic valve energy using a mechanical spring system, the CTAMD system recovers kinetic energy in a magnetic field. This allows for high efficiency while maintaining a simple and elegant electromechanical design. This paper describes the characteristics of CTAMD systems and outlines an electromechanical design for such a system. Then computer simulations of the proposed design are used to demonstrate the expected performance of the system. Finally, the simulated results are compared to other EVA systems to highlight the anticipated improvements.

A Versatile Acceleration-Based Cam Profile for Single-Dwell Applications Requiring Cam-Follower Clearance During Dwell

2011 ◽  
Author(s):  
Forrest W. Flocker
Keyword(s):  
High Speed ◽  
Internal Combustion Engines ◽  
Internal Combustion ◽  
Combustion Engines ◽  
Velocity Function ◽  
Gas Leakage ◽  
Poppet Valve ◽  
Equation Solving ◽  
Cam Follower ◽  
Cam Profile

Presented in this paper is a cam motion program suitable for single-dwell cam-follower systems with built-in clearance between the cam and follower during the dwell portion of the cycle. This makes the motion program particularly well-suited to applications such as valve trains in internal combustion engines in which cam-follower clearance is necessary to ensure proper seating of a poppet valve, preventing gas leakage across the seal. The motion program for the cam follower is derived from the follower acceleration function so that designers can control the ratio of the magnitudes of positive and negative accelerations. This provides cam designers more control over the cam-follower interface force and therefore more control over factors such as cam wear and the potentially destructive phenomenon known as “follower jump.” Included in the motion program is asymmetric rise and fall that allows different times for these events. The follower acceleration is designed to be smooth enough to provide continuous jerk throughout the actuation phase, thereby tending to reduce undesirable residual vibrations. The motion program used to close and open the clearance gap is derived from a velocity function, allowing more control of follower inertia during the important clearance closing event. The motion program is presented in a form appropriate for implementation in standard engineering equation-solving software, giving the cam designer easy control over important parameters in high-speed cam-follower systems.

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