scholarly journals Field of Work and Energy Efficiency of Hydrostatic Drives on the Example of Two Tested Systems with Proportional Control of the Cylinder’s Speed

2019 ◽  
Vol 49 (4) ◽  
pp. 203-219
Author(s):  
Grzegorz Skorek
Keyword(s):  
Energy Efficiency ◽  
Power Flow ◽  
Drive System ◽  
Energy Losses ◽  
Test Results ◽  
Hydraulic Motor ◽  
Power Increase ◽  
Physical Quantities ◽  
Direction Opposite

Abstract The presented test results are an example of simulating determination of the hydrostatic field of the drive system and the energy efficiency of the system as a dependence on the speed and load coefficients of the hydraulic motor used in the system. The issues related to the determination of energy losses and energy efficiency of the hydraulic motor or drive system, which should be determined as dependent on the physical quantities independent of these losses, were also discussed. A Paszota diagram of the power increase in the direction opposite to the direction of the power flow, replacing the Sankey diagram of the power decrease in the direction of the power flow in the hydraulic motor or in the drive system was analyzed.

scholarly journals On Power Stream in Motor or Drive System

2016 ◽  
Vol 23 (4) ◽  
pp. 93-98 ◽  
Author(s):  
Zygmunt Paszota
Keyword(s):  
Energy Efficiency ◽  
Thermal Efficiency ◽  
Power Flow ◽  
Drive System ◽  
Energy Losses ◽  
Flow Energy ◽  
Power Increase ◽  
Drive Systems ◽  
Physical Quantities ◽  
Direction Opposite

Abstract In a motor or a drive system the quantity of power increases in the direction opposite to the direction of power flow. Energy losses and energy efficiency of a motor or drive system must be presented as functions of physical quantities independent of losses. Such quantities are speed and load. But the picture of power stream in a motor or drive system is presented in the literature in the form of traditional Sankey diagram of power decrease in the direction of power flow. The paper refers to Matthew H. Sankey’s diagram in his paper „The Thermal Efficiency of Steam Engines“ of 1898. Presented is also a diagram of power increase in the direction opposite to the direction of power flow. The diagram, replacing the Sankey’s diagram, opens a new prospect for research into power of energy losses and efficiency of motors and drive systems.

scholarly journals Effect of the working liquid compressibility on the picture of volumetric and mechanical losses in a high pressure displacement pump used in a hydrostatic drive

2012 ◽  
Vol 19 (2) ◽  
pp. 3-10 ◽  
Author(s):  
Zygmunt Paszota
Keyword(s):  
High Pressure ◽  
Power Flow ◽  
Mechanical Energy ◽  
Drive System ◽  
Energy Losses ◽  
Hydraulic Motor ◽  
Power Increase ◽  
Liquid Compressibility ◽  
Displacement Pump ◽  
Working Liquid

Effect of the working liquid compressibility on the picture of volumetric and mechanical losses in a high pressure displacement pump used in a hydrostatic drive Working liquid compressibility may considerably change the values and proportions of coefficients of volumetric and mechanical energy losses in the displacement pump used in a hydrostatic drive system. This effect can be particularly seen in the operation under high pressure and also in the system, where aeration of the working liquid can occur. In the Part I a diagram is presented, proposed by the author, of power increase in a hydrostatic drive system (hydraulic motor, pump) opposite to the direction of power flow, replacing the Sankey diagram of power decrease in the direction of power flow. Mathematical model is presented of volumetric losses in the pump and its laboratory verification.

scholarly journals Determination of Coefficients of Energy Losses Occurring in a Constant Capacity Pump Working in a Typical Hydrostatic Drive

2019 ◽  
Vol 26 (1) ◽  
pp. 159-166
Author(s):  
Grzegorz Skorek
Keyword(s):  
Energy Efficiency ◽  
Drive System ◽  
Energy Losses ◽  
Motor Speed ◽  
Hydraulic Motor ◽  
Viscosity Change ◽  
Building Models ◽  
Nominal Pressure ◽  
Low Efficiency ◽  
Drive Systems

Abstract In order to assess possibilities of energy saving during hydrostatic drive system operation, should be learned, and described losses occurring in system. Awareness of proportion of energy, volume, pressure, and mechanical losses in elements is essential for improving functionality and quality of hydrostatic drive systems characterized by unquestionable advantages. In systems with too low efficiency there is increase of load, mainly in case of pump load, which can lead to higher risk of failure, necessity of repair or replacement, as well as to shorten service life of system. Coefficients ki, given in subject literature by Paszota, describe relative value of individual losses in element. They make it possible to assess proportions of losses and assess value of energy efficiency (volumetric, pressure, mechanical) resulting from losses occurring at nominal pressure pn of system in which element is used. As a result, thanks to knowledge of coefficients ki of individual losses, it is possible to determine losses and energy efficiency of components operating in hydraulic system as well as efficiency of system with defined structure of motor speed control as function of speed and load coefficient of motor. Knowledge of coefficients of energy losses occurring in system elements (pump, hydraulic motor, conduits, and motor) allows building models of losses and energy efficiency of element working in system and energy efficiency of system as whole composed of elements. Mathematical models of losses and energy efficiency in system must take into account conditions resulting from applied structure of system, from level of nominal pressure, from rotational speed of motor driving pump shaft, from viscosity change of applied hydraulic oil. Article presents method of determining coefficients of axial piston pump used in typical hydrostatic drive system with proportional control. Values that can be assumed for these loss coefficients for other hydraulic pumps are also given.

scholarly journals Measuring Instruments Used at the Research and Accuracy of Defining the Efficiency of Drive Systems

2019 ◽  
Vol 26 (2) ◽  
pp. 129-135
Author(s):  
Grzegorz Skorek
Keyword(s):  
Energy Efficiency ◽  
Test Stand ◽  
Energy Losses ◽  
Measuring Instruments ◽  
Motor Speed ◽  
Hydraulic Motor ◽  
Accuracy Of Measurements ◽  
Drive Systems ◽  
The Mathematical Model

Abstract The aim of the article is to look at the possibility of accurately determining the energy efficiency of drive systems thanks to the use of high quality sensors and measuring instruments. The types of measuring instruments used on the test stand are presented. The results of experimentally determined efficiencies and simulationally determined efficiencies of two hydrostatic systems with throttling control were compared, which are fed with a constant capacity pump. The choice of the analysed systems is not accidental. There is still a view in the literature about limited possibilities of energy systems with proportional control. The research stand was very carefully designed and made. The applied measuring instruments were characterized by high accuracy of measurements. The issues related to the determination of energy losses and energy efficiency of the engine or drive system, which should be determined as dependent on the physical quantities independent of these losses, were also discussed. For laboratory verification, measurement methods were developed, the test stand was adapted and automated. It consists of tested system and loaded system. The measurements during the tests were saved on the computer disk. In order to be able to compare the efficiency of the overall system with the efficiency obtained on the basis of the simulation, coefficients ki determining the energy losses of individual elements of the system were calculated. The research showed a large convergence of the mathematical description of energy losses in the elements of the system and the efficiency of the system with reality. The mathematical model enables accurate simulation determination of the energy efficiency of the system at each point of its field of operation, i.e. at each speed and load of the controlled hydraulic motor. The range of motor speed and load variation can also be accurately determined simulationally.

scholarly journals Interaction Boundary Determination of Renewable Energy Sources to Estimate System Strength Using the Power Flow Tracing Strategy

2021 ◽  
Vol 13 (3) ◽  
pp. 1569
Author(s):  
Namki Choi ◽  
Byongjun Lee ◽  
Dohyuk Kim ◽  
Suchul Nam
Keyword(s):  
Renewable Energy ◽  
Power Flow ◽  
Renewable Energy Sources ◽  
Energy Sources ◽  
Test Results ◽  
Boundary Determination ◽  
Actual Interaction ◽  
Power Flow Tracing ◽  
Estimate System

System strength is an important concept in the integration of renewable energy sources (RESs). However, evaluating system strength is becoming more ambiguous due to the interaction of RESs. This paper proposes a novel scheme to define the actual interaction boundaries of RESs using the power flow tracing strategy. Based on the proposed method, the interaction boundaries of RESs were identified at the southwest side of Korea Electric Power Corporation (KEPCO) systems. The test results show that the proposed approach always provides the identical interaction boundaries of RESs in KEPCO systems, compared to the Electric Reliability Council of Texas (ERCOT) method. The consistent boundaries could be a guideline for power-system planners to assess more accurate system strength, considering the actual interactions of the RESs.

scholarly journals Energy efficiency of different bus subsystems in Belgrade public transport

2015 ◽  
Vol 19 (6) ◽  
pp. 2233-2244
Author(s):  
Slobodan Misanovic ◽  
Zlatomir Zivanovic ◽  
Slaven Tica
Keyword(s):  
Energy Efficiency ◽  
Simulation Model ◽  
Experimental Determination ◽  
Public Transport ◽  
Drive System ◽  
Theoretical Simulation ◽  
Driving Cycles ◽  
Electric Bus

Research in this paper comprised experimental determination of energy efficiency of different bus subsystems (diesel bus, trolleybus and fully electric bus) on chosen public transport route in Belgrade. Experimental measuring of energy efficiency of each bus type has been done based on the analysis of parameters of vehicle driving cycles between stops. Results of this analysis were basis for development of theoretical simulation model of energy efficiency. The model was latter compared with the results of simulation done by "Solaris bus & Coach" company for the chosen electric bus route. Based on demonstrated simulation, characteristics of electric bus batteries were defined, the method and dynamic of their recharge was suggested, as well as choice for other aggregates for drive system and technical characteristics for the electric buses were suggested.

scholarly journals Method of Sum of Power Losses as a Way for Determining the ki Coefficients of Energy Losses in Hydraulic Motor

2016 ◽  
Vol 23 (2) ◽  
pp. 57-63 ◽  
Author(s):  
A. Maczyszyn
Keyword(s):  
Power Flow ◽  
Laboratory Data ◽  
Energy Losses ◽  
Power Losses ◽  
Hydraulic Motor ◽  
Rotary Motor

Abstract This paper shows application of the method of sum of power losses to determining energy losses which occur in hydraulic rotary motor in situation when not all laboratory data are at one’s disposal or when no use is made of data contained in catalogue charts. The method makes it possible to determine the coefficients, ki, of energy losses occurring in the motor. The method of sum of power losses is based on the approach proposed by Z. Paszota, in the papers [3 ÷ 9]. It consists in adding power flow of energy losses occurring in the motor to power flow output and comparing the sum to the power flow input. Application of the method is exemplified by using a A6VM hydraulic motor.

scholarly journals Energy Loss Coefficients ki in a Displacement Pump and Hydraulic Motor used in Hydrostatic Drives

2019 ◽  
Vol 26 (3) ◽  
pp. 47-55
Author(s):  
Agnieszka Maczyszyn
Keyword(s):  
Energy Efficiency ◽  
Energy Loss ◽  
Machine Design ◽  
Energy Losses ◽  
Operating Parameters ◽  
Hydraulic Motor ◽  
Mechanical Loss ◽  
Design And Manufacturing ◽  
Displacement Pump ◽  
Loss Coefficients

Abstract The article aims at defining and analysing the energy loss coefficients in design solutions of rotating displacement machines, with a piston machine as an example. The energy losses observed in these machines include mechanical loss, volumetric loss, and pressure loss. The scale and relations between these losses in different machines depend on machine design and manufacturing quality, and on operating parameters. The operating parameters, in turn, which affect directly or indirectly the above losses depend on whether the machine works in pump or hydraulic motor regime. The article is also a contribution to the development of a library of ki coefficients which define the losses in displacement machines, as the knowledge about these coefficients makes it possible to assess fast and easily the energy efficiency of a machine or drive system at each point of its working area.

scholarly journals Losses and energy efficiency of drive motors and systems

2013 ◽  
Vol 20 (1) ◽  
pp. 3-10 ◽  
Author(s):  
Zygmunt Paszota
Keyword(s):  
Energy Efficiency ◽  
Power Flow ◽  
Objective Evaluation ◽  
Drive System ◽  
Motor Speed ◽  
Rotational Displacement ◽  
Operating Field ◽  
Useful Power ◽  
New Perspective ◽  
Drive Systems

Abstract Losses and energy efficiency of every drive motor must be presented as functions of physical quantities independent of losses in the motor. Such quantities are speed and load required by the machine or device driven by the motor, changing in the drive operating field. Speed and load of the motor decide of the instantaneous useful power of the motor and also in a differentiated way of kinds and values of losses occurring in the motor. However, losses and energy efficiency of the hydrostatic drive motors and systems are evaluated by researchers and manufacturers as functions of parameters depending on the losses. The basic cause of such situation is the traditional, commonly accepted but erroneous, view of the power flow in the drive motors and systems represented by the Sankey diagram of power decrease in the direction of power flow. It is necessary to replace the Sankey diagram by the proposed diagram of increase of power in the motor and in the drive system in the direction opposite to the direction of power flow. The proposed view of losses and energy efficiency should be applied to all types of motor and drive systems. The aim of this paper is showing the resulting problems of the above postulates, exemplified by operation of a rotational displacement motor in a hydrostatic drive system. In order to make possible objective evaluation of the energy behaviour of different motor and system solutions and sizes, the losses and energy efficiency should be described and compared as dependent on the motor speed coefficient ωM and load coefficient M changing in the drive system operating field (0 ≤ ωM< ωMmax, 0 ≤ M< Mmax). The presented proposals open a new perspective of unavoidable research of drive motors and systems, making it possible to compare objectively the energy efficiency of different types of motors and drive systems.

scholarly journals Determination of the Theoretical and Actual Working Volume of a Hydraulic Motor—Part II (The Method Based on the Characteristics of Effective Absorbency of the Motor)

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1648
Author(s):  
Pawel Sliwinski
Keyword(s):  
Pressure Drop ◽  
Rotational Speed ◽  
Nonlinear Function ◽  
Energy Losses ◽  
Hydraulic Motor ◽  
Volume Calculation ◽  
Method Of Determination ◽  
Actual Working ◽  
Working Volume

In this article, the second method of determination of the theoretical and actual working volume of a hydraulic motor is described. The proposed new method is based on the characteristics of effective absorbency of the motor. The effective absorbency has been defined as the ratio of flow rate in a motor to the rotational speed of the motor’s shaft. It has been shown that the effective absorbency is a nonlinear function of the rotational speed and nonlinear function of the pressure drop in the motor’s working chambers. Furthermore, it has been proven that the actual working volume of a motor is a function of a third degree of pressure drop in the motor’s working chamber. The actual working volume should be taken to assess the mechanical and volumetric energy losses in the motor. Furthermore, the influence of the flowmeter location in the measurement system and the compressibility of liquid on the result of the theoretical and actual working volume calculation was also taken into account and is described in this article. The differences in the assessment of the volumetric efficiency assuming the theoretical and actual working volume was also shown.

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