The Experts below are selected from a list of 9726 Experts worldwide ranked by ideXlab platform
James D Van De Ven - One of the best experts on this subject based on the ideXlab platform.
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CRANK-SLIDER Spool VALVE FOR SWITCH-MODE CIRCUITS
2016Co-Authors: Alexander C Yudell, Shaun E Koktavy, James D Van De VenAbstract:A key component of switch-mode hydraulic circuits is a high-speed two-position three-way valve with a variable duty cycle. This paper presents a new valve architecture that consists of two valve Spools that are axially driven by crank-slider mechanisms. By phase shifting the two crank links, which are on a common crankshaft, the duty cycle of the valve is adjusted. The two Spools split and re-combine flow such that two switching cycles occur per revolution of the crankshaft. Because the Spools move in a near-sinusoidal trajectory, the peak Spool velocities are achieved at mid-stroke where the valve land transitions across the ports, resulting in short valve transition times. The Spool velocity is lower during the remainder of the cycle, reducing viscous friction losses. A dynamic model is constructed of this new valve operating at 120 Hz switching frequency in a switch-mode circuit. The model is used to illustrate design trade-offs and minimize energy losses in the valve. The resulting design solution transitions to the on-state in 5 % of the switching period and the combined leakage and viscous friction in the valve dissipate 1.7 % of the total power at a pressure of 34.5MPa and volumetric flow rate of 22.8L/min
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crank slider Spool valve for switch mode circuits
ASME BATH 2015 Symposium on Fluid Power and Motion Control FPMC 2015, 2015Co-Authors: Alexander C Yudell, Shaun E Koktavy, James D Van De VenAbstract:A key component of switch-mode hydraulic circuits is a high-speed two-position three-way valve with a variable duty cycle. This paper presents a new valve architecture that consists of two valve Spools that are axially driven by crank-slider mechanisms. By phase shifting the two crank links, which are on a common crankshaft, the duty cycle of the valve is adjusted. The two Spools split and re-combine flow such that two switching cycles occur per revolution of the crankshaft. Because the Spools move in a near-sinusoidal trajectory, the peak Spool velocities are achieved at mid-stroke where the valve land transitions across the ports, resulting in short valve transition times. The Spool velocity is lower during the remainder of the cycle, reducing viscous friction losses. A dynamic model is constructed of this new valve operating at 120 Hz switching frequency in a switch-mode circuit. The model is used to illustrate design trade-offs and minimize energy losses in the valve. The resulting design solution transitions to the on-state in 5% of the switching period and the combined leakage and viscous friction in the valve dissipate 1.7% of the total power at a pressure of 34.5MPa and volumetric flow rate of 22.8L/min.Copyright © 2015 by ASME
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IMECE2007-42559 HIGH SPEED ROTARY PULSE WIDTH MODULATED ON/OFF VALVE ∗
2010Co-Authors: Michael B. Rannow, James D Van De Ven, Meng Wang, Thomas R. ChaseAbstract:A key enabling technology to effective on/off valve based control of hydraulic systems is the high speed on/off valve. High speed valves improve system efficiency, offer faster control bandwidth, and produce smaller output pressure ripples. Current valves rely on the linear translation of a Spool or poppet to meter flow. The valve Spool must reverse direction twice per PWM cycle. This constant acceleration and deceleration of the Spool requires a power input proportional to the PWM frequency cubed. As a result, current linear valves are severely limited in their switching frequencies. In this paper, we present a novel PWM on/off valve design that is based on a unidirectional rotary Spool. The on/off functionality of our design is achieved via helical barriers that protrude from the surface of a cylindrical Spool. As the Spool rotates, the helical barriers selectively channel the flow to the application (on) or to tank (off). The duty ratio is controlled by altering the axial position of the Spool. Since the Spool no longer accelerates or decelerates during operation, the power input to drive the valve must only compensate for viscous friction, which is proportional to the PWM frequency squared. We predict that our current design, sized for a nominal flow rate of 40l/m, can achieve a PWM frequency of 84Hz. This is roughly a 400 % improvement over current designs. This paper presents our valve concept, design equations, and an analysis of predicted performance. A simulation of our design is also presented.
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IMECE2007-42559 HIGH SPEED ROTARY PULSE WIDTH MODULATED ON/OFF VALVE ∗
2007Co-Authors: Michael B. Rannow, James D Van De Ven, Meng Wang, Thomas R. ChaseAbstract:A key enabling technology to effective on/off valve based control of hydraulic systems is the high speed on/off valve. High speed valves improve system efficiency for a given PWM fre-quency, offer faster control bandwidth, and produce smaller out-put pressure ripples. Current valves rely on the linear translation of a Spool or poppet to meter flow. The valve Spool must re-verse direction twice per PWM cycle. This constant acceleration and deceleration of the Spool requires a power input proportional to the PWM frequency cubed. As a result, current linear valves are severely limited in their switching frequencies. In this paper, we present a novel fluid driven PWM on/off valve design that is based on a unidirectional rotary Spool. The Spool is rotated by capturing momentum from the fluid flow through the valve. The on/off functionality of our design is achieved via helical barri-ers that protrude from the surface of a cylindrical Spool. As the Spool rotates, the helical barriers selectively channel the flow to the application (on) or to tank (off). The duty ratio is controlled by altering the axial position of the Spool. Since the Spool no longer accelerates or decelerates during operation, the power in-put to drive the valve must only compensate for viscous friction, which is proportional to the PWM frequency squared. We predict that our current design, sized for a nominal flow rate of 40l/m, can achieve a PWM frequency of 84Hz. This paper presents our valve concept, design equations, and an analysis of predicted per-formance. A simulation of our design is also presented.
Eckhard A Groll - One of the best experts on this subject based on the ideXlab platform.
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development of a loss pareto for a rotating Spool compressor using high speed pressure measurements and friction analysis
Applied Thermal Engineering, 2016Co-Authors: Craig R Bradshaw, Greg Kemp, Joe Orosz, Eckhard A GrollAbstract:Abstract A rotating Spool compressor is a new compressor technology that was recently introduced by Kemp et al. in 2008. To accelerate the development of the technology, a breakdown of the key losses within the 5th generation device is presented. The losses include indicated losses associated with leakage and over/under compression due to valves and porting. These losses are obtained using high-speed pressure measurements to obtain an indicator diagram of the 5th generation device. Additionally, frictional losses associated with the key sealing elements and moving components are calculated. An experimental validation of the Spool seal friction sub-model is presented. All of these losses are combined into Pareto of losses for the 5th generation Spool compressor. This Pareto identified the Spool seals, compression and discharge flow losses, and the friction of the Top Dead Center interface as losses to be addressed in future designs. Using this information efforts to improve these components were integrated into a 6th generation Spool compressor. This generation recorded an overall isentropic efficiency of over 80% for a net improvement of nearly 15 percentage points over the 5th generation Spool compressor.
Thomas R. Chase - One of the best experts on this subject based on the ideXlab platform.
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IMECE2007-42559 HIGH SPEED ROTARY PULSE WIDTH MODULATED ON/OFF VALVE ∗
2010Co-Authors: Michael B. Rannow, James D Van De Ven, Meng Wang, Thomas R. ChaseAbstract:A key enabling technology to effective on/off valve based control of hydraulic systems is the high speed on/off valve. High speed valves improve system efficiency, offer faster control bandwidth, and produce smaller output pressure ripples. Current valves rely on the linear translation of a Spool or poppet to meter flow. The valve Spool must reverse direction twice per PWM cycle. This constant acceleration and deceleration of the Spool requires a power input proportional to the PWM frequency cubed. As a result, current linear valves are severely limited in their switching frequencies. In this paper, we present a novel PWM on/off valve design that is based on a unidirectional rotary Spool. The on/off functionality of our design is achieved via helical barriers that protrude from the surface of a cylindrical Spool. As the Spool rotates, the helical barriers selectively channel the flow to the application (on) or to tank (off). The duty ratio is controlled by altering the axial position of the Spool. Since the Spool no longer accelerates or decelerates during operation, the power input to drive the valve must only compensate for viscous friction, which is proportional to the PWM frequency squared. We predict that our current design, sized for a nominal flow rate of 40l/m, can achieve a PWM frequency of 84Hz. This is roughly a 400 % improvement over current designs. This paper presents our valve concept, design equations, and an analysis of predicted performance. A simulation of our design is also presented.
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IMECE2007-42559 HIGH SPEED ROTARY PULSE WIDTH MODULATED ON/OFF VALVE ∗
2007Co-Authors: Michael B. Rannow, James D Van De Ven, Meng Wang, Thomas R. ChaseAbstract:A key enabling technology to effective on/off valve based control of hydraulic systems is the high speed on/off valve. High speed valves improve system efficiency for a given PWM fre-quency, offer faster control bandwidth, and produce smaller out-put pressure ripples. Current valves rely on the linear translation of a Spool or poppet to meter flow. The valve Spool must re-verse direction twice per PWM cycle. This constant acceleration and deceleration of the Spool requires a power input proportional to the PWM frequency cubed. As a result, current linear valves are severely limited in their switching frequencies. In this paper, we present a novel fluid driven PWM on/off valve design that is based on a unidirectional rotary Spool. The Spool is rotated by capturing momentum from the fluid flow through the valve. The on/off functionality of our design is achieved via helical barri-ers that protrude from the surface of a cylindrical Spool. As the Spool rotates, the helical barriers selectively channel the flow to the application (on) or to tank (off). The duty ratio is controlled by altering the axial position of the Spool. Since the Spool no longer accelerates or decelerates during operation, the power in-put to drive the valve must only compensate for viscous friction, which is proportional to the PWM frequency squared. We predict that our current design, sized for a nominal flow rate of 40l/m, can achieve a PWM frequency of 84Hz. This paper presents our valve concept, design equations, and an analysis of predicted per-formance. A simulation of our design is also presented.
J Y Lew - One of the best experts on this subject based on the ideXlab platform.
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modeling and control of two stage twin Spool servo valve for energy saving
American Control Conference, 2005Co-Authors: Qinghui Yuan, J Y LewAbstract:A control strategy of two stage twin Spool servovalves in the load-sensing mobile applications is presented. The twin Spool valve differs from the conventional valve in that it provides the ability to control flow into and out of valves independently. In this paper, the nonlinear valve model and a control scheme for a two stage twin Spool servo-valve are developed featuring energy saving. The multiple sliding surface mode control method is then utilized to accomplish the motion control while regulating back pressure. The simulation verifies that the proposed control scheme for the twin Spool valve, can offer the more significant energy-saving even with load-sensing pump application than the traditional proportional valves.
Qinghui Yuan - One of the best experts on this subject based on the ideXlab platform.
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Using Steady Flow Force for Unstable Valve Design: Modeling and Experiments
2013Co-Authors: Qinghui YuanAbstract:Abstract — In single stage valves, the main Spools are stroked directly by solenoid actuators. They are cheaper and more reliable than multistage valves. Their use, however, is restricted to low bandwidth and low flow rate applications due to the limitation of the solenoid actuators. Our research focuses on alleviating the need for large and expensive solenoids in single stage valves by advantageously using fluid flow forces. For example, in a previous paper, we proposed to improve Spool agility by inducing unstable transient flow forces by the use of negative damping lengths. In the present paper, how steady flow forces can be manipulated to improve Spool agility is examined through fundamental momentum analysis, CFD analysis and experimental studies. Particularly, it is found that two previously ignored components- viscosity effect and non-orifice momentum flux, have strong influence on steady flow forces. For positive damping lengths, viscosity increases the steady flow force, whereas for negative damping lengths, viscosity has the tendency of reducing steady flow forces. Also, by slightly modifying the non-orifice port geometry, the non-orifice flux can also be manipulated so as to reduce steady flow force. Therefore, both transient and steady flow forces, can also be used to improve the agility of single stage electrohydraulic valves
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using steady flow force for unstable valve design modeling and experiments
Journal of Dynamic Systems Measurement and Control-transactions of The Asme, 2005Co-Authors: Qinghui YuanAbstract:In single stage electrohydraulic valves, solenoid actuators are usually used to stroke the main Spools directly. They are cheaper and more reliable than multistage valves. Their use, however, is restricted to low bandwidth and low flow rate applications due to the limitation of the solenoid actuators. Our research focuses on alleviating the need for large and expensive solenoids in single stage valves by advantageously using fluid flow forces. For example, in a previous paper, we proposed to improve Spool agility by inducing unstable transient flow forces by the use of negative damping lengths. In the present paper, how steady flow forces can be manipulated to improve Spool agility is examined through fundamental momentum analysis, CFD analysis, and experimental studies. Particularly, it is found that two often ignored components-viscosity effect and non-metering momentum flux, have strong influence on steady flow forces. For positive damping lengths, viscosity increases the steady flow force, whereas for negative damping lengths, viscosity has the tendency to reduce steady flow forces. Also, by slightly modifying the non-metering port geometry, the non-metering flux can also be manipulated to reduce steady flow force. Therefore, both transient and steady flow forces can be used to improve the agility of single stage electrohydraulic valves. Experimental results confirm the contributions of both transient and steady flow force in improving Spool agility.
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modeling and control of two stage twin Spool servo valve for energy saving
American Control Conference, 2005Co-Authors: Qinghui Yuan, J Y LewAbstract:A control strategy of two stage twin Spool servovalves in the load-sensing mobile applications is presented. The twin Spool valve differs from the conventional valve in that it provides the ability to control flow into and out of valves independently. In this paper, the nonlinear valve model and a control scheme for a two stage twin Spool servo-valve are developed featuring energy saving. The multiple sliding surface mode control method is then utilized to accomplish the motion control while regulating back pressure. The simulation verifies that the proposed control scheme for the twin Spool valve, can offer the more significant energy-saving even with load-sensing pump application than the traditional proportional valves.
