Overall Efficiency Evaluation of a Hydraulic Pump With External Drainage Through Temperature Measurements

Abstract

In the recent years, industries have been working on the online condition monitoring of systems and components in order to definitely abandon the time-based maintenance and switch efficiently to a condition-based maintenance. Therefore, the research field related to prognostics and health management (PHM) has been gaining more and more importance. In the field of hydraulic pumps and motors, the overall efficiency is an important parameter to monitor and the thermodynamic method has historically been proposed for the online evaluation of this parameter for hydraulic machines without external drainage. Indeed, for this kind of machines, the thermodynamic method allows the evaluation of the overall efficiency by measuring only the temperatures and the pressures at the suction and the delivery ports, thus avoiding the use of cumbersome and expensive sensors, such as flow meters and torque sensors. This paper investigates the use of the thermodynamic method for hydraulic machines with external drainage. The case study of a swash-plate type axial-piston pump is considered. In this first part of the project, the objective was to validate the proposed thermodynamic method by comparing its results with the ones obtained through the mechanical, therefore an extensive experimental activity was carried out and two flow meters were used to measure the drainage and the delivery flow rates. The pump was tested in different operating conditions and the uncertainty related to the overall efficiency was calculated accurately in order to compare the two approaches properly.

Application of a hydraulic gas bladder suppressor for pressure ripple reduction in gear pumps

“…Passive systems for mitigating flow ripple are primarily based on the utilization of elastic components that enable the damping of flow and pressure fluctuations. These kind of devices are able to reduce the pressure ripple in relevant manner, a drawback is that they are bulky respect the pump size, another aspect to be evaluated is the compatibility with the implementation of condition-based maintenance relies on an effective prognostics and health management (PHM) system, whose function is to identify if and when maintenance action is required [12,13]. In [14], Shang employed a springtype accumulator to diminish the first harmonic of flow ripple generated by an axial piston pump.…”

Excavator hydraulic circuit solution to reduce dissipations and fuel consumption

“…Mathematical models are necessaries for evaluating different solutions, the models could be based on lumped parameters approach for the systems simulation [10][11][12][13][14][15] while when a component needs to be optimized dedicated detailed models should be developed; the literature reports research activities carried out on gear pumps [16][17][18][19][20][21]; fixed displacement gerotor pump are investigated in [22][23][24][25][26][27]. Particular applications like lubrication pump are investigated in [28][29][30]; topics concerning the condition monitoring applied to hydraulic pumps are reported in [31,32]; other papers are focused on detailed analysis of hydraulic valves [33][34][35]. Focused on excavator hydraulic solutions in [36] is presented a system with two pumps that permits to feed users with similar load reducing the compensator losses.…”

CFD Analyses of Textured Surfaces for Tribological Improvements in Hydraulic Pumps

“…As a further step, the simulations have been carried out considering the phenomenon of gaseous cavitation. In hydraulic applications, some operating conditions able to onset local cavitating phenomena could occur, with serious consequences on the operation of the machines [9][10][11][12][13]. The cavitation represents a negative aspect even in the presence of a textured surface, since it modifies the coupling performance, and in some cases, it could lead to unwanted and counterproductive effects.…”