Theoretical and experimental studies of the steady-state performance of a primary and secondary-controlled closed-circuit hydrostatic drive

In this article, performance of a closed-circuit hydrostatic drive in primary and secondary mode of operations has been studied through theory and experiment. This drive consists of a variable displacement pump that supplies pressurized fluid to a variable displacement hydro-motor of bent axis design. Bond graph simulation method is adopted for system modeling. In the model, the losses of the drive are accounted by suitable resistive elements, and their characteristics are identified through experiments. The predicted drive’s performances are studied with respect to the overall efficiency, torque loss (%), and slip at different torque levels which are also validated experimentally. The investigation made in the article identifies the efficient zone of operation of the drive which will be useful to the practicing engineers to select such a drive used in heavy constructional equipment. From the steady-state performance of the pump and the motor, their critical control parameters are identified. The studies may be useful for the design of the suitable control strategy to obtain the optimum performance of the drives.

Download Full-text

Steady-state performance investigation of closed-circuit hydrostatic drive using variable displacement pump and variable displacement motor

Proceedings of the Institution of Mechanical Engineers Part E Journal of Process Mechanical Engineering ◽

10.1177/0954408920953662 ◽

2020 ◽

pp. 095440892095366

Author(s):

Vinay Partap Singh ◽

Ajit Kumar Pandey ◽

Kabir Dasgupta

Keyword(s):

Steady State ◽

Closed Circuit ◽

Control Parameters ◽

Prime Mover ◽

Load Torque ◽

Wide Range ◽

Displacement Pump ◽

Variable Displacement ◽

Overall Performance ◽

Steady State Performance

This article investigates the steady-state performance of a closed-circuit hydrostatic (HST) drive using a variable displacement pump and a variable displacement motor where the speed of the drive is varied by controlling pump or motor. The drive is operated over a wide range of load torque and speed in two modes of operation: the pump controlled mode and the motor controlled mode. The efficiencies of the pump, motor, and the prime mover driving the pump are taken into account to analyze the overall performance of the drive. In this respect, considering various flow and torque losses of the HST drive components, the equations representing efficiencies of the drive are identified by comparing with the experimental data. The simulation is carried out using MATLAB. The results of the study may be useful to identify the control parameters of the drive to operate it at a reasonable efficiency zone.

Download Full-text

Steady-state performance investigation of hydrostatic summation drive using bent-axis hydraulic motor

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/0954406214559410 ◽

2014 ◽

Vol 229 (17) ◽

pp. 3234-3251 ◽

Cited By ~ 4

Author(s):

N Kumar ◽

K Dasgupta

Keyword(s):

Steady State ◽

Performance Studies ◽

State Variables ◽

Hydraulic Motor ◽

Displacement Pump ◽

Torque Loss ◽

Variable Displacement ◽

Loss Coefficients ◽

Overall Efficiency ◽

Steady State Performance

This article investigates the steady-state performance of a closed-circuit hydrostatic summation drive used in heavy earth moving machine through modelling and experiment. The proposed drive basically consists of variable displacement pump and bent-axis motor. The performance studies of the drive have been made for its two different modes of operation: using single motor and two motors. Bondgraph simulation technique is used to model the drive, where various losses are lumped into suitable resistive elements. The relationships of the losses with the state variables obtained from the model are identified through experiments. The dependencies of the loss characteristics on the load torque and the pump displacement ratio are studied. The model has been verified experimentally. The performances of the hydrostatic drives are studied at different torque levels with respect to its slip, torque-loss and overall efficiency, using the expressions describing the characteristics of the loss-coefficients. The investigation also identifies the operating range of the proposed hydrostatic drives with reasonable efficiency.

Download Full-text

Steady-state performance investigation of open-circuit hydrostatic drives used in the rotary head of drill machine

Proceedings of the Institution of Mechanical Engineers Part E Journal of Process Mechanical Engineering ◽

10.1177/0954408917738973 ◽

2017 ◽

Vol 233 (1) ◽

pp. 3-20 ◽

Cited By ~ 1

Author(s):

Alok Vardhan ◽

K Dasgupta ◽

N Kumar ◽

Santosh Kr Mishra

Keyword(s):

Steady State ◽

High Speed ◽

Mining Operation ◽

Open Circuit ◽

Alternative Drive ◽

Displacement Pump ◽

Torque Loss ◽

Drive Systems ◽

Low Torque ◽

Steady State Performance

This paper highlights the steady-state performance of open-circuit hydrostatic drives for the rotary head of drill machine through modeling and experiment. In this respect, two alternative drive systems are considered. A drive system that consists of a variable displacement pump and two high-speed low-torque hydro-motors with a gear reducer unit and the other one consists of an identical pump and a low-speed high-torque hydro-motor. The steady-state model of the proposed drive arrangements is made by bondgraph simulation technique, where the relationship of the various losses of the components are obtained as a function of operating parameters and are identified experimentally. Using them, the slip and torque loss along with the overall efficiency of the drives are characterized. The performances of the hydrostatic drives are compared for the usual operating speed range of the drill machine used in mining operation. The studies made also identify the operating range of the proposed hydrostatic drives with reasonable efficiency.

Download Full-text

Experimental Study on the Steady-State Performance of Closed-Circuit Hydrostatic Transmission Drives for the Rotary Head of Blast Hole Drill Machine Using Different Capacities Bent Axis Hydro-Motor

Lecture Notes in Mechanical Engineering - Advances in Engineering Design ◽

10.1007/978-981-13-6469-3_9 ◽

2019 ◽

pp. 93-103

Author(s):

Alok Vardhan ◽

K. Dasgupta ◽

Mohit Bhola

Keyword(s):

Experimental Study ◽

Steady State ◽

Blast Hole ◽

Closed Circuit ◽

Hydrostatic Transmission ◽

Steady State Performance

Download Full-text

Software Enabled Variable Displacement Pumps: Experimental Studies

Fluid Power Systems and Technology ◽

10.1115/imece2006-14973 ◽

2006 ◽

Cited By ~ 10

Author(s):

Michael B. Rannow ◽

Haink C. Tu ◽

Perry Y. Li ◽

Thomas R. Chase

Keyword(s):

Experimental Studies ◽

Check Valve ◽

Design Parameters ◽

Duty Ratio ◽

System Response ◽

Experimental Apparatus ◽

Displacement Pump ◽

Variable Displacement ◽

Valve Control ◽

Variable Displacement Pumps

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.

Download Full-text

Experimental investigation on the steady-state performance and piston stroke length control of a variable displacement wobble plate compressor

Proceedings of the Institution of Mechanical Engineers Part D Journal of Automobile Engineering ◽

10.1243/095440705x5911 ◽

2005 ◽

Vol 219 (2) ◽

pp. 271-281 ◽

Cited By ~ 1

Author(s):

Changqing Tian ◽

Chunpeng Dou ◽

Xianting Li ◽

Yunfei Liao

Keyword(s):

Experimental Investigation ◽

Steady State ◽

Test Data ◽

Air Conditioning ◽

Volumetric Efficiency ◽

Stroke Length ◽

Variable Displacement ◽

Rotary Speed ◽

Piston Stroke ◽

Steady State Performance

The aim of this paper is to find out the steady-state performance and piston-stroke-length control behaviour of a variable displacement wobble-plate compressor for an automotive air-conditioning system by experimental investigation. First, a new method and device to measure the piston stroke length of the variable displacement compressor has been developed, with which the test bench for the variable displacement compressor has been set up. Second, the steady-state performance of the variable displacement compressor, such as the relative volumetric efficiency and the relative isentropic efficiency at partial piston stroke length, has been obtained. The influence of the work condition and compressor rotary speed on the relative volumetric efficiency can be neglected according to the test data. Finally, the critical wobble-plate case pressure is proposed in this paper to judge whether the piston stroke length will change or not. The critical wobble-plate case pressure when the piston stroke length decreases is greater than that when the piston stroke length increases, which is less influenced by the piston stroke length itself from the test data. The higher the compressor discharge pressure or rotary speed, the greater the critical wobble-plate case pressure. The piston stroke length can be adjusted automatically along with the air-conditioning load when the compressor rotary speed or air conditioning load changes.

Download Full-text

Theoretical and experimental studies on the steady-state performance of low-speed high-torque hydrostatic drives. Part 2: Experimental investigation

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1243/09544062jmes1203 ◽

2009 ◽

Vol 223 (11) ◽

pp. 2675-2685 ◽

Cited By ~ 9

Author(s):

S K Mandal ◽

K Dasgupta ◽

S Pan ◽

A Chattopadhyay

Keyword(s):

Steady State ◽

Experimental Studies ◽

Open Circuit ◽

Control Parameters ◽

Low Speed ◽

Hydrostatic Transmission ◽

Loss Coefficients ◽

High Torque ◽

Steady State Performance

The performance investigations of an open-circuit and a closed-circuit low-speed high-torque hydrostatic drive are presented. The modelling of both drives and determination of their loss coefficients are presented in Part 1 of this article (pg. 2663 of this issue). This study determines and analyses the overall efficiency and slip characteristics of the hydrostatic drives using the expressions describing the characteristics of their loss coefficients. The effects of critical control parameters of the pumps and the motor are investigated on the basis of their steady-state performance. This investigation is based on the performance of the hydrostatic transmission drives at different torque levels.

Download Full-text

Theoretical and Experimental Studies of the Steady State Performance of an Orbital Rotor Low-Speed High-Torque Hydraulic Motor

Proceedings of the Institution of Mechanical Engineers Part A Journal of Power and Energy ◽

10.1243/pime_proc_1996_210_070_02 ◽

1996 ◽

Vol 210 (6) ◽

pp. 423-429 ◽

Cited By ~ 11

Author(s):

K Dasgupta ◽

A Mukherjee ◽

R Maiti

Keyword(s):

Mathematical Model ◽

Steady State ◽

Experimental Studies ◽

Engineering Systems ◽

Hydraulic Motor ◽

Low Speed ◽

High Torque ◽

Complex Variation ◽

Structured Approach ◽

Steady State Performance

In this paper the steady state performance of epitrochoid generated orbital ‘rotary piston machine’ (ROPIMA) type ‘low-speed high-torque’ (LSHT) hydrostatic unit has been studied. The complex variation of the volume of a chamber of such a machine with shaft rotation, along with the various flow and torque losses, demand a structured approach to arrive at its mathematical model. In conventional approaches the system morphology becomes obscured as the mathematical model is approached. Bondgraph provides a structured approach to model engineering systems in a simplified manner. A reduced Bondgraph model of the LSHT Orbital motor is made where the various losses are lumped in suitable resistive elements. The variations of the loss coefficients are identified. The predicted performance of the motor has been experimentally verified.

Download Full-text

Experimental Studies of a Novel Alternating Flow (AF) Hydraulic Pump

ASME/BATH 2017 Symposium on Fluid Power and Motion Control ◽

10.1115/fpmc2017-4315 ◽

2017 ◽

Author(s):

Ryan J. Foss ◽

Mengtang Li ◽

Eric J. Barth ◽

Kim A. Stelson ◽

James D. Van de Ven

Keyword(s):

Phase Angle ◽

Experimental Studies ◽

Companion Paper ◽

Pump Efficiency ◽

Operating Pressure ◽

Displacement Control ◽

Displacement Pump ◽

Pressure Dynamics ◽

Variable Displacement ◽

Control Circuits

The ideal variable displacement pump for a displacement control circuit is efficient across a wide operating range and readily mounted on a common shaft with multiple pumps. This paper presents a novel variable displacement pump architecture for displacement control circuits that uses the concept of alternating flow (AF) between piston pairs that share a common cylinder. The displacement is adjusted by varying the phase angle between the piston pairs. When the pistons are in phase, the pump displacement is at a maximum and when the pairs of pistons are out of phase, fluid is shuttled between the pistons and the pump produces no net flow. A prototype of the AF pump was constructed from two inline triplex pumps that were modified so that three piston pairs were created. The crankshafts of the two pumps were connected via a sprocket-and-chain transmission. The sprockets allow for accurate measurement of the phase angle, which is adjusted, in this early phase prototype, by disassembling the chain and shifting the sprockets. The prototype AF pump was then mounted to the test stand and experiments were conducted to map the AF pump efficiency and cylinder pressure dynamics across a range of operating pressure, speed, and displacement. The AF pump’s efficiency was measured for 8 diferent phase angles with an efficiency of near 90% at full flow and 65% at 36% displacement. The experimental results were compared to simulation results, presented in a companion paper at this conference.

Download Full-text