Comparison of Analytical and Experimental Investigations of a Hydraulic Multi-Circuit Sequential Apportioning System

Luo, Nianzhu; Fronczak, Frank J.; Beachley, Norman H.

doi:10.4271/901553

Cited by 2 publications

(2 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Other on/off configurations, such as the multicircuit approach described in Ref. [7], cannot use check valves to reduce the transition loss and require more complicated techniques.…”

Section: Soft Switching Conceptmentioning

confidence: 99%

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

Rannow

2009

ASME 2009 Dynamic Systems and Control Conference, Volume 1

View full text Add to dashboard Cite

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 when the switching times are not negligible. 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 81% and total system losses by 64%. The soft switching approach has the potential to improve the efficiency of on/ off controlled systems and is particularly beneficial 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 of an on/off valve that was 4.4 times faster.

show abstract

“…Other on/off configurations, such as the multicircuit approach described in Ref. [7], cannot use check valves to reduce the transition loss and require more complicated techniques.…”

Section: Soft Switching Conceptmentioning

confidence: 99%

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

Rannow

2009

ASME 2009 Dynamic Systems and Control Conference, Volume 1

View full text Add to dashboard Cite

show abstract

“…Proposals to use on/off valves to control fluid power systems have been around for awhile. For example, Luo et al [10] proposed an apportioning system based on synchronized pilot operated poppet valves in the late 1980's. In recent years, there has been a resurgence of activities in this area, partly due to the wide spread use of electrohydraulic concepts.…”

Section: Introductionmentioning

confidence: 99%

Software Enabled Variable Displacement Pumps: Experimental Studies

Rannow

et al. 2006

Fluid Power Systems and Technology

View full text Add to dashboard Cite

The majority of hydraulic systems are controlled using a metering valve or the use of variable displacement pumps. Metering valve control is compact and has a high control bandwidth, but it is energy inefficient due to throttling losses. Variable displacement pumps are far more efficient as the pump only produces the required flow, but comes with the cost of additional bulk, sluggish response, and added cost. In a previous paper [1], a hydromechanical analog of an electronic switch-mode power supply was proposed to create the functional equivalent of a variable displacement pump. This approach combines a fixed displacement pump with a pulse-width-modulated (PWM) on/off valve, a check valve, and an accumulator. The effective pump displacement can be varied by adjusting the PWM duty ratio. Since on/off valves exhibit low loss when fully open or fully closed, the proposed system is potentially more energy efficient than metering valve control, while achieving this efficiency without many of the shortcomings of traditional variable displacement pumps. The system also allows for a host of programmable features that can be implemented via control of the PWM duty ratio. This paper presents initial experimental validation of the concept as well as an investigation of the system efficiency. The experimental apparatus was built using available off-the-shelf components and uses a linear proportional spindle valve as the PWM valve. Experimental results confirm that the proposed approach can achieve variable control function more efficiently than a valve controlled system, and that by increasing the PWM frequency and adding closed-loop control can decrease system response times and of the output ripple magnitude. Sources of inefficiency and their contributions are also investigated via modeling, simulation and are validated by experiments. These indicate design parameters for improving inefficiency.

show abstract

Comparison of Analytical and Experimental Investigations of a Hydraulic Multi-Circuit Sequential Apportioning System

Cited by 2 publications

References 4 publications

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

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

Software Enabled Variable Displacement Pumps: Experimental Studies

Contact Info

Product

Resources

About