scholarly journals Study of Energy Efficiency Characteristics of a Hydraulic System Component

2020 ◽  
Author(s):  
Alamgir Choudhury ◽  
Prajna Paramita ◽  
Jorge Rodriguez
Author(s):  
Niko Karlén ◽  
Tatiana Minav ◽  
Matti Pietola

Several types of off-road machinery, such as industrial trucks, forklifts, excavators, mobile cranes, and wheel loaders, are set to be operated in environments which can differ considerably from each other. This sets certain limits for both the drive transmissions and working hydraulics of these machines. The ambient temperature must be taken into account when selecting the hydraulic fluid since the viscosity and density of the fluid are changing at different operating temperatures. In addition to the temperature, energy efficiency can also be a problem in off-road machinery. In most off-road machines, diesel engines are employed to produce mechanical energy. However, there are energy losses during the working process, which causes inefficiency in produced energy. For better energy efficiency, hybridization in off-road machinery is an effective method to decrease fuel consumption and increase energy savings. One of the possible methods to save energy with hybrids is energy regeneration. However, it means that the basic hydraulic system inside off-road machinery needs to be modified. One solution for this is to utilize zonal or decentralized approach by means of direct driven hydraulic (DDH) system. This paper aims to investigate a DDH system for off-road machinery by means of modelling and analyzing the effect of the temperature. In the direct-driven hydraulic system, the actuator is controlled directly by the hydraulic pump which is operated by the electric motor. Specifically, it is a valveless closed-loop hydraulic system. Thus, there will be no energy losses caused by the valves, and the total efficiency is assumed to be significantly higher. In order to examine the DDH system, a thermo-hydraulic model was created. Additionally, a thermal camera was utilized in order to illustrate the temperature changes in the components of the DDH system. To reproduce the action of the system in different circumstances DDH system was run at different ambient temperatures, and the component temperatures in the system were measured and saved for the analysis. The thermo hydraulic model was proven capable to follow the general trend of heating up.


2012 ◽  
Vol 516-517 ◽  
pp. 892-895 ◽  
Author(s):  
Jun Gao ◽  
Guo Yi Yan ◽  
Gen Yun Peng ◽  
Guan Nan Xi

As we known, the energy efficiency of pump-control system is higher than valve-control system. So, using pump-control system to replace valve-control system has a positive meaning to improve the energy efficiency in hydraulic press machine. In order to research the performance of servo pump used in hydraulic press machines, the present study is conducted. First, a test bench for comparison of pump-control and valve-control system is established. In this test bench, the pump of former valve-control system and the servo pump are settled. These two pumps are switched by solenoid to supply oil for the hydraulic system. Then, host PC, target PC, I/O board and other hard-wares are connected. Soft-wares and the corresponding driver board are applied to collect data. In order to test the performances of the pressure, velocity and displacement under the condition of the valve-control system and pump-control system, the two systems are tested with the same working conditions. The performance of repeatability and energy efficiency are also obtained. The results show that it’s feasible to apply servo pump to hydraulic press machine. And under the pump-control condition, the velocity and pressure performance of press machine is more stable.


Author(s):  
V. Vanin ◽  
M. Kruhol

The work is devoted to the study of thermal power plants auxiliary energy efficiency. The main mechanisms in the auxiliary systems are centrifugal mechanisms that work in complex hydraulic networks with variable productivity. The main ways to adjust the parameters of the centrifugal mechanisms are to change the speed of rotor rotation, change the guide vane angle and throttle. The operation mode of a complex hydraulic network which includes a group of centrifugal mechanisms with a mixed connection scheme is analyzed. The system of equations which characterize the hydraulic system has been obtained on the basis of Kirchhoff's laws. The centrifugal mechanisms' operating characteristics are given by approximation dependences obtained with the method of least squares and similarity laws. To analyze efficiency of different methods of centrifugal mechanisms parameters regulation, optimal control problems were set and solved. The constraints for the problems are a system of equations that describe the hydraulic system operation and technical constraints that depend on the control method. Through solving the problems, values of the optimal parameters and weighted average efficiency of the group mechanisms were obtained. Studies have shown that the most effective way to regulate the centrifugal mechanisms parameters is to use an individual frequency drive, the least effective is to use only changing angle of centrifugal mechanism's guide vane. Utilization of group control is highly efficient and not inferior to individual frequency drive. However, this statement is correct under condition of the operating characteristics agreement with the centrifugal mechanisms’ operating modes similarity.


2006 ◽  
Author(s):  
Lois J. Gschwender ◽  
Angie Campo ◽  
Carl E. Snyder ◽  
Shashi K. Sharma ◽  
Tim Jenney ◽  
...  

2021 ◽  
Vol 64 (5) ◽  
pp. 1435-1448
Author(s):  
Xin Tian ◽  
Patrick Stump ◽  
Andrea Vacca ◽  
Stefano Fiorati ◽  
Francesco Pintore

HighlightsTwo methods (VPM and HVM) are proposed to improve the hydraulic system efficiency of agricultural tractors.VPM and HVM both target reducing the power loss at the flow control valve of the hydraulic system.The solutions are presented conceptually and then numerically modeled, and VPM is tested on an actual tractor.Results show that the VPM solution achieves 6.7% power saving, while HVM achieves 15.6% power saving.Abstract. Load sensing (LS) is a dominant fluid power actuation technology in mobile machines, particularly in construction and agriculture. It has the advantage of guaranteeing good controllability in systems with multiple actuators while promoting higher energy efficiency. Several variants of LS systems have been proposed over the years, and research on cost-effective methods to further increase their efficiency is still of interest for original equipment manufacturers (OEMs) and the fluid power community. This article presents two solution, referred to as variable pump margin (VPM) and hybrid variable margin (HVM), suitable to improve the energy efficiency in pre-compensated LS systems such as those used in agricultural tractors. Both methods allow either downsizing the control valves or reducing the power consumption over the working range. Compared to a standard LS system, the VPM solution lowers the pump pressure using an electronic proportional pressure-reducing valve (ep-PRV), while the HVM solution uses a second ep-PRV in the compensator’s pilot line to further minimize the pressure differential across the LS valve. Simulation and experimental results show that, among the main working conditions, the VPM solution on average achieved 6.7% power saving over the standard LS system, while the model predicted an average improvement of 15.6% for the HVM solution. Keywords: Efficiency, Experiments, Hydraulic, Load sensing, Modeling, Pump.


2014 ◽  
Vol 50 (2) ◽  
pp. 1313-1321 ◽  
Author(s):  
Franklin L. Quilumba ◽  
Lyndon K. Lee ◽  
Wei-Jen Lee ◽  
Alan Harding

Author(s):  
Mengdi Gao ◽  
Haihong Huang ◽  
Xinyu Li ◽  
Zhifeng Liu

The energy efficiency of the piston pumps is one of the considerable important factors in design and analysis of hydraulic system, especially in the process of real-time tracking of energy dissipation in a variety of loading conditions. The existing methods for obtaining the energy efficiency curve of piston pumps are either time-consuming or inaccurate. In order to quantify the energy efficiency of the piston pumps quickly and accurately, the leakage and friction energy loss caused by the clearances in the sliding pairs are analyzed, and an overall efficiency model was established, which contains two constants to be determined by two test points. The accuracy of the model was verified based on a test rig for a hydraulic pump, and it can be improved by selecting appropriate test points via the method of deviation analysis. The results show that the proposed efficiency models are in good agreement with the experimental results, and the best test points are in the range of 0–25% and 51–75% of the peak pressure of the investigated piston pump.


2014 ◽  
Vol 931-932 ◽  
pp. 403-407
Author(s):  
Weerapong Chanbua ◽  
Unnat Pinsopon

At the present time, researchers try to find alternative fluids for being used as lubricants or hydraulic fluids that are biodegradable and environmental friendly. In this study, Refined-Bleached-Deodorized (RBD) palm olein was investigated whether it is such a potential candidate. RBD palm olein could be easily acquired since it is of the type used as cooking oil. The physical properties of both conventional hydraulic oil and RBD palm olein were tested and compared by an accredited laboratory. The performance of the hydraulic systems when using both fluids as working mediums were also tested and compared. The experimental results show that temperature significantly affected the performance of the hydraulic system when using conventional hydraulic oil, whereas the performance of the hydraulic system when using RBD palm olein barely changed with temperatures. At the temperatures below 60 °C, the RBD palm olein yielded less flow rate and less energy efficiency. However, for the temperatures above 60 °C, the RBD palm olein yielded slightly more flow rate and slightly more energy efficiency. It can be confirmed from this study that RBD palm olein can be used as an alternative hydraulic fluid.


2020 ◽  
Vol 22 (1-2) ◽  
pp. 72-78
Author(s):  
Dejvid Anastasovski ◽  
◽  
Emil Zaev ◽  
Darko Babunski ◽  
Gerhard Rath ◽  
...  

The main goal of the research done in this paper is to examine possible improvements in energy efficiency of the hydraulic power systems and with this lower gas emission from working machinery. It is here given a brief explanation of the existing hydraulic systems putting special attention on a hydraulic system with separate meter-in and separate meter-out (SMISMO). While the aim of this research is to improve the hydraulic energy efficiency mainly using the SMISMO system, additional research on using those systems for simultaneous speed and pressure control of the cylinders is also observed. The results obtained through experimental studies will be used to further improve the hydraulic system. Further upgrade of this system is to design automated SCADA system for improved data acquisition and control the valves in servo systems.


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