Thermo-Hydraulic Modelling and Experimental Validation of an Electro-Hydraulic Compact Drive

Ketelsen, Søren; Michel, Sebastian; Andersen, Torben Ole; Ebbesen, Morten Kjeld; Weber, Jürgen; Schmidt, Lasse

doi:10.3390/en14092375

Cited by 12 publications

(9 citation statements)

References 41 publications

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“…The cylinder power is obtained as the product of the measured actuation velocity and the loading force. The formula is given in Equation (11).…”

Section: Resultsmentioning

confidence: 99%

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Experimental Verification of An Electro-Hydraulic Actuation System Driven by An Integrated Electro-Hydraulic Unit

Qu¹,

Zappaterra²,

Vacca³

et al. 2023

TJFP

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This paper proposes an electro-hydraulic actuator (EHA) system, and a novel-designed electro-hydraulic unit (EHU) consisting of a fixed-displacement hydraulic gear machine and a variable-speed electric machine. The novel EHU design integrates an electric machine and a hydraulic machine in a single housing, targeting optimal compactness, power density, and component reduction. The EHA system features an open circuit design, where hydraulic hoses connect the EHU with a tank, a valve manifold, and the hydraulic cylinder. In this way, the proposed EHA technology can be used to implement distributed hydraulic actuation in a vehicle without requiring changes to the hydraulic actuators or at the overall layout of the hydraulic components with respect to the original vehicle design. A dedicated test rig is developed to verify the performance of the proposed EHA system. The efficiency of the EHA is measured in a steady state and under a realistic duty cycle of a commercial compact loader. The efficiency of the EHA system based on the measurements on the test rig can reach 54% with up to 20 kN load and 6 kW power level. Furthermore, the EHU is implemented on the reference machine to drive the boom function. Preliminary results on the performance of the EHU show an efficiency of up to 68% under different loading conditions.

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“…The cylinder power is obtained as the product of the measured actuation velocity and the loading force. The formula is given in Equation (11).…”

Section: Resultsmentioning

confidence: 99%

“…Nevertheless, the adoption of self-contained EHAs in off-road vehicles is challenged by the cost and space requirement, which in many cases requires modification of the mechanical structures. The thermal behavior of the self-contained EHA could be another concern based on some previous studies [10,11].…”

Section: Introductionmentioning

confidence: 99%

Experimental Verification of An Electro-Hydraulic Actuation System Driven by An Integrated Electro-Hydraulic Unit

Qu¹,

Zappaterra²,

Vacca³

et al. 2023

TJFP

View full text Add to dashboard Cite

show abstract

“…It was observed that the temperatures of the two thermocouples were very similar to each other for every power level, indicating a high rate of heat transfer from the pump housing to the fluid being pumped. Ketelsen et al [19] used a similar approach which lumped the thermal capacitances of multiple components including the pump, motor, and oil to predict the temperature of a larger EHA system with accuracy suitable for design purposes. The metal compression fitting conducts heat from the pump housing very well and appears to reach temperatures near that of the pump housing, as shown in Figure 2a.…”

Section: Thermal Performance Resultsmentioning

confidence: 99%

Performance Assessment of a Low-Cost Miniature Electrohydrostatic Actuator

Deibert

Wiens

2022

Actuators

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Low-cost small-scale (<100 W) electrohydrostatic actuators (EHAs) are not available on the market, largely due to a lack of suitable components. Utilizing plastic 3D printing, a novel inverse shuttle valve has been produced which, when assembled with emerging small-scale hydraulic pumps and cylinders from the radio-controlled hobby industry, forms a low-cost and high-performance miniature EHA. This paper presents experimental test results that characterize such a system and highlight its steady, dynamic, and thermal performance capabilities. The results indicate that the constructed EHA has good hydraulic efficiency downstream of the pump and good dynamic response but is limited by the efficiency of the pump and the associated heat generated from the pump’s losses. The findings presented in this paper validate the use of a 3D printed plastic inverse shuttle valve in the construction of a low-cost miniature EHA system.

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“…Since throttling losses are supposed to be small in pump-controlled systems, the need for cooling is much smaller compared to conventional valve-controlled systems, but it may still be required. Ketelsen et al has analysed the thermal properties and concluded that passive cooling may be sufficient for a power range of 5-10 kW [86].…”

Section: Auxiliary Functionsmentioning

confidence: 99%

On Electrified Fluid Power Systems in Mobile Machinery

Kärnell

2022

Linköping Studies in Science and Technology. Dissertations

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High power density in combination with flexible power distribution possibilities and extreme robustness are reasons why fluid power has been the preferred technology in mobile machinery, such as excavators and cranes, since the mid-20th century. In principle, the machines have been powered by a combustion engine which powers a pump, with the output from the pump being distributed to different functions via valves. However, a transformation is currently underway. Combustion engines are being replaced by electric motors, and batteries able to store energy corresponding to several hours of operation are often desired. Since batteries tend to be heavy and expensive, reducing the energy consumption is getting higher priority than ever before. There are applications where electrification means that hydraulic components are replaced by electric counterparts, but fluid power has characteristics that are highly desirable in mobile machinery. Therefore, many hydraulic actuators will remain. Conventional hydraulic systems, which are known for their inefficiency, should, however, be adapted to the new conditions brought about by electrification. The question, and the overall subject of this thesis, is: how? The research has focused on two main topics: pump-controlled systems, which are systems where each actuator has its own supply unit, and the use of variable displacement pumps in electrified systems.A large proportion of the losses in many conventional hydraulic systems is due to the simultaneous operation of functions that require different pressure levels. One way to avoid these losses is to use pump-controlled systems. How these systems should be designed is, however, far from obvious. In this thesis, different types of pump-controlled systems are compared, both statically and dynamically.Regarding variable displacement pumps, they have had a natural place in many conventional systems, but electrification may change this, since speedcontrol can now also be used for flow-and pressure control. However, there are still aspects relating to energy consumption and component dimensioning, among other things, that makes variable pumps relevant. These aspects are investigated here, and different types of variable pumps are reviewed.Linköping, August 2022 Samuel Kärnell v vi PapersThe following publications are included in the thesis and can be regarded as its foundation. They will be referred to by their Roman numerals. Apart from formatting changes, they are reproduced in their original form. Notice that they are not appended in chronological order. Instead, they are sorted based on the topics; the first three focus on displacement control and the last two on pump-controlled systems.[I] S. Kärnell and L. Ericson, "Classification and review of variable displacement fluid power pumps and motors," International Journal of Fluid Power (submitted), 2022.[II] S. Kärnell, A. Rankka, A. Dell'Amico, and L. Ericson, "Digital pumps in speed-controlled systems -an energy study for a loader crane application," in

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Thermo-Hydraulic Modelling and Experimental Validation of an Electro-Hydraulic Compact Drive

Cited by 12 publications

References 41 publications

Experimental Verification of An Electro-Hydraulic Actuation System Driven by An Integrated Electro-Hydraulic Unit

Experimental Verification of An Electro-Hydraulic Actuation System Driven by An Integrated Electro-Hydraulic Unit

Performance Assessment of a Low-Cost Miniature Electrohydrostatic Actuator

On Electrified Fluid Power Systems in Mobile Machinery

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