Direct Actuation of Large Sized Valves by a Hydraulically Relieved Electromechanical Actuation System

2021 ◽  
Author(s):  
Tobias Vonderbank ◽  
Pierre Marc Laßl Chavez ◽  
Katharina Schmitz
Keyword(s):  
Critical Conditions ◽  
Neutral Position ◽  
Hydraulic Systems ◽  
Power Outage ◽  
Controlled Systems ◽  
Actuation System ◽  
Directional Control ◽  
Nominal Size ◽  
Spring Force ◽  
Valve Actuation

Extensive actuation forces and strokes are required for the actuation of large sized valves normally implemented in high power hydraulic systems. A hydraulically piloted operation is, for now, the most suitable solution and state of the art. However, there are some applications where electromechanical valve actuation systems are at advantage against common pilot operation systems. In this contribution it is analyzed in which cases the application of electro-mechanical actuators can be of advantage and why displacement-controlled systems may be one of these applications. A novel electromechanical valve actuation system for large sized 4/3-way directional control valves for the use in displacement-controlled systems is presented. This new actuation system is characterized by a hydraulic relief of the centering springs. Therefore, the springs are only active in safety-critical conditions, such as a power outage. Since the actuator is not working against the spring force during every displacement, the necessary actuation force is reduced drastically. Thus, common electromechanical actuators can be used. In case of a power outage, the spring relief is deactivated causing the stored energy to center the spool in its neutral position. The performance of the novel actuation system is examined through measurements conducted on a manufactured demonstrator for valves of nominal size 25 with a flow rate of up to 600 l/min.

Soft Switching Approach to Reducing Transition Losses in an On/Off Hydraulic Valve

2009 ◽  
Author(s):  
Michael B. Rannow ◽  
Perry Y. Li
Keyword(s):  
Hydraulic System ◽  
Check Valve ◽  
Fluid Flows ◽  
Soft Switching ◽  
Total System ◽  
System Efficiency ◽  
Hydraulic Systems ◽  
Controlled Systems ◽  
Flow Through ◽  
Hydraulic Valve

A method for significantly reducing the losses associated with an on/off controlled hydraulic system is proposed. There has been a growing interest in the use of on/off valves to control hydraulic systems as a means of improving system efficiency. While on/off valves are efficient when they are fully open or fully closed, a significant amount of energy can be lost in throttling as the valve transitions between the two states. A soft switching approach is proposed as a method of eliminating the majority of these transition losses. The operating principle of soft switching is that fluid can temporarily flow through a check valve or into a small chamber while valve orifices are partially closed. The fluid can then flow out of the chamber once the valve has fully transitioned. Thus, fluid flows through the valve only when it is in its most efficient fully open state. A model of the system is derived and simulated, with results indicating that the soft switching approach can reduce transition and compressibility losses by 79%, and total system losses by 66%. Design equations are also derived. The soft switching approach has the potential to improve the efficiency of on/off controlled systems and is particularly important as switching frequencies are increased. The soft switching approach will also facilitate the use of slower on/off valves for effective on/off control; in simulation, a valve with soft switching matched the efficiency an on/off valve that was 5 times faster.

Effects of design and operating parameters on the static and dynamic performance of an electromagnetic valve actuator

2003 ◽  
Vol 217 (3) ◽  
pp. 193-201 ◽  
Author(s):  
S-H Park ◽  
J Lee ◽  
J Yoo ◽  
D Kim ◽  
K Park
Keyword(s):  
Simulation Model ◽  
New Technology ◽  
Dynamic Performance ◽  
Operating Parameters ◽  
Computer Simulation Model ◽  
Neutral Position ◽  
Electromagnetic Valve ◽  
Actuation System ◽  
Si Engines ◽  
Actuation Devices

The electromagnetic valve (EMV) actuation system is a new technology for improvement in fuel effciency and reduction in emissions in spark ignition (SI) engines. It can provide more flexibility in valve event control compared with conventional variable valve actuation devices. However, a more powerful and effcient actuator design is needed for this technology to be applied in mass production engines. This paper presents the effects of design and operating parameters on the static and dynamic performances of the actuator. Employing the finite element method (FEM), the flow pattern of the magnetic flux is analysed and the resultant magnetic forces of several cases of core and armature designs are calculated. A computer simulation model has been set up to identify the dynamic behaviour of the EMV system. The effects of external disturbances such as cylinder pressure, armature neutral position and current supply time are also analysed. To verify the accuracy of the simulation model, an experimental study is also carried out on a prototype actuator. It is found that there is relatively good agreement between the experimental data and the results from the simulation model. The newly designed actuator is successfully operated on the test bench up to about 6000 r/min, which is the range of rated speed of most production SI engines. Through the whole speed range, the actuator maintains good performance in valve timing and event control.

scholarly journals Cavitation Inception in Spool Valves

1981 ◽  
Vol 103 (4) ◽  
pp. 564-575 ◽  
Author(s):  
C. Samuel Martin ◽  
H. Medlarz ◽  
D. C. Wiggert ◽  
C. Brennen
Keyword(s):  
Reynolds Number ◽  
Hydraulic Systems ◽  
Cavitation Inception ◽  
Pressure Transducers ◽  
High Frequency Response ◽  
Annular Jet ◽  
Directional Control ◽  
Valve Opening ◽  
Response Pressure ◽  
Spool Valves

Cavitation has been investigated in directional control valves in order to identify damage mechanisms characteristic of components of aircraft hydraulic systems. Tests have been conducted in a representative metal spool valve and in a model three times larger. Data taken under noncavitating conditions with both valves showed that the position of the high-velocity annular jet shifts orientation, depending upon valve opening and Reynolds number. By means of high-frequency response pressure transducers strategically placed in the valve chamber cavitation could be sensed by the correlation of noise with a cavitation index. The onset of cavitation can be detected by comparing energy spectra for a fixed valve opening and a constant discharge. Another sensitive indicator of cavitation inception is the ratio of cavitating to noncavitating spectral densities. The incipient cavitation number as defined in this investigation is correlated with the Reynolds number for both valves.

EASY5 Model of Two Position Solenoid Operated Cartridge Valve

2002 ◽  
Author(s):  
Song Liu ◽  
Gary Krutz ◽  
Bin Yao
Keyword(s):  
Control Valve ◽  
Mathematic Model ◽  
Nonlinear Flow ◽  
Damping Force ◽  
Precise Control ◽  
Directional Control ◽  
Spring Force ◽  
Programmable Valve ◽  
Valve Dynamics ◽  
Nonlinear Performance

The two position solenoid operated cartridge valve is widely used in the applications, such as process control systems, pavers, agricultural machinery, where response and installed costs are more important than precise control through electronic position feedback. In recent years, the combination of multiple cartridge valves, so called ‘smart valve’ or ‘programmable valve’, which is able to break the mechanical linkage between the meter-in and meter-out orifices and enables high precision control as well as optimal usage of energy, is gaining engineering interests. But the control of such combination is far from trivial. It demands good knowledge of the valve dynamics and nonlinear flow properties. Unlike servo valve or proportional directional control valve, a mathematic model of solenoid operated cartridge valve, or even a thorough understanding of the dynamics and nonlinear performance, are not available. This paper presents an EASY 5 model for the two position solenoid operated cartridge valve. The model, which includes the solenoid force, spring force, damping force, flow force and nonlinear mass flow rate, can be used to analyze cartridge valve as well as simulate system or controller performance. It is also able to connect with Matlab for more complicated simulation.

Preliminary Failure Analysis and Structural Design of a Morphing Winglet for Green Regional Aircraft

2018 ◽  
Author(s):  
Ignazio Dimino ◽  
Salvatore Ameduri ◽  
Antonio Concilio
Keyword(s):  
Failure Analysis ◽  
Structural Design ◽  
Failure Modes ◽  
Structural Response ◽  
Operational Reliability ◽  
Control Device ◽  
Critical Conditions ◽  
Next Generation ◽  
Novel Technologies ◽  
Actuation System

Aircraft wing design optimization typically requires the consideration of many competing factors accounting for both aerodynamics and structures. To address this, research on morphing aircraft has shown its potential by providing large benefits on aircraft performance. In particular, by adapting wing lift distribution, morphing winglets are capable to improve aircraft aerodynamic efficiency in off-design conditions and reduce wing loads at critical flight points. For those reasons, it is expected that these devices will be applied to the aircraft of the very next generation. In the study herein presented, a preliminary failure analysis and structural design of a morphing winglet are presented. The research is collocated within the Clean Sky 2 Regional Aircraft IADP, a large European programme targeting the development of novel technologies for the next generation regional aircraft. The safety-driven design of the proposed kinematic system includes a thorough examination of the potential hazards associated with the system faults, by taking into account the overall operating environment and functions. The mechanical system is characterized by movable surfaces sustained by a winglet skeleton and completely integrated with a devoted actuation system. Such a load control device requires sufficient operational reliability to operate on the applicable flight load envelope in order to match the needs of the structural design. One of the most critical failure modes is assessed to get key requirements for the system architecture consistency. Possible impacts of the defined morphing outline on the FHA analysis are investigated. The structural design process is then addressed in compliance with the demanding requirements posed by the implementation on regional airplanes. The layout static robustness is verified by means of linear stress analyses at the most critical conditions, including possible failure scenarios. Results focus on the assessment of the device static and dynamic structural response and the preliminary definition of the morphing system kinematics, including the integrated actuator system.

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