Research Progress on Hydraulic Fluid and Hydraulic Systems

A special issue of Applied Sciences (ISSN 2076-3417). This special issue belongs to the section "Mechanical Engineering".

Deadline for manuscript submissions: 30 June 2024 | Viewed by 3003

Special Issue Editors

Faculty of Mechanical Engineering, University of Maribor, SI-2000 Maribor, Slovenia
Interests: hydraulics; pneumatics; automation; Industry 4.0; maintenance; condition monitoring; testing device
Faculty of Mechanical Engineering, University of Maribor, SI-2000 Maribor, Slovenia
Interests: hydraulics and pneumatics; automation; maintenance; development; testing

Special Issue Information

Dear Colleagues,

Progress in the field of hydraulic drive and control technology is seen not only in the field of components and systems, but also in hydraulic fluids. At the forefront of the development of hydraulic components and systems are ever-higher operating pressures, tighter tolerances in components, demands for greater efficiency, new materials and higher energy density of components and systems. Hydraulic fluids with their material properties must also adapt to these trends and follow them. Hydraulic systems are smaller, and so residence times are shorter and circulation numbers are higher; the desired temperature operating range should be as wide as possible, and both the energy efficiency and environmental friendliness are improved. There is also a demand for the universal use of the liquid, or for the fulfillment of special operating conditions and requirements, such as those arising from difficult, harsh operating conditions or special use cases.

The subject matter of this Special Issue relates to the latest developments in the field of hydraulic fluids and corresponding hydraulic systems. It covers a very wide area, from innovations and findings related to different types of liquids to their individual material properties and to testing and areas of application, and on the other hand, to the systems, which also have to be adopted for the new fluid types. It also addresses the field concerned with the energy suitability of the used liquid as well as issues of its environmental suitability.

Prof. Dr. Vito Tič
Prof. Dr. Darko Lovrec
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Applied Sciences is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • hydraulic fluids
  • hydraulic systems
  • conventional
  • alternative and new fluids
  • energy saving fluids
  • high-performance fluids
  • material properties
  • additives
  • operational conditions
  • testing
  • material compatibility
  • standards
  • applications

Published Papers (3 papers)

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Research

14 pages, 966 KiB  
Article
Ionic Hydraulic Fluids and Seal-Material Compatibility
by Darko Lovrec, Roland Kalb and Vito Tič
Appl. Sci. 2024, 14(5), 2187; https://doi.org/10.3390/app14052187 - 05 Mar 2024
Viewed by 435
Abstract
Manufacturers of hydraulic fluids invest a lot of effort and resources in improving their physico-chemical properties, with the goal of getting as close as possible to the properties of an ideal hydraulic fluid. It should be non- flammable, environmentally friendly, sustainable and should [...] Read more.
Manufacturers of hydraulic fluids invest a lot of effort and resources in improving their physico-chemical properties, with the goal of getting as close as possible to the properties of an ideal hydraulic fluid. It should be non- flammable, environmentally friendly, sustainable and should have excellent physical and chemical properties. After decades of development in the field of ionic liquids and the search for an ionic liquid suitable for use in hydraulic systems, ionic hydraulic liquids are now already in industrial use, especially on devices that operate in harsh and risky operating conditions. Since ionic hydraulic fluids are a completely new type of hydraulic fluid, one of the issues is their compatibility with the materials present in the hydraulic components, including all the seals. This paper refers to the process of testing the compatibility of hydraulic seal materials with different types of ionic hydraulic fluids according to the standardized percentages and recommendations, with emphasis on changes in the swell, shrinkage and hardness of the seals. The presented results are a useful guide for selecting suitable seal materials in case of using high-tech ionic hydraulic fluids. Full article
(This article belongs to the Special Issue Research Progress on Hydraulic Fluid and Hydraulic Systems)
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20 pages, 8807 KiB  
Article
Degradation of Hydraulic System due to Wear Particles or Medium Test Dust
by Nejc Novak, Ana Trajkovski, Mitjan Kalin and Franc Majdič
Appl. Sci. 2023, 13(13), 7777; https://doi.org/10.3390/app13137777 - 30 Jun 2023
Viewed by 1237
Abstract
Contamination in hydraulic systems is the cause of 70% of failures. This study highlights the performance degradation caused by solid particle contamination of hydraulic components: hydraulic gear pump, 4/3 valve, and orbital motor. Experimental durability tests of components with wear particles and test [...] Read more.
Contamination in hydraulic systems is the cause of 70% of failures. This study highlights the performance degradation caused by solid particle contamination of hydraulic components: hydraulic gear pump, 4/3 valve, and orbital motor. Experimental durability tests of components with wear particles and test dust are used to investigate the effects of accelerated wear caused by these two types of contaminants. Results show that oil contaminated with wear particles reduces the volumetric efficiency of the gear pump by 18% and the hydraulic valve by only 0.8%, while oil contaminated with test dust reduces the efficiency of the pump by 76% and the hydraulic valve by 0.9%. This research provides insights for accelerating hydraulic component testing to improve system reliability and longevity. Full article
(This article belongs to the Special Issue Research Progress on Hydraulic Fluid and Hydraulic Systems)
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14 pages, 5522 KiB  
Article
Performance of Polymer Composites Lubricated with Glycerol and Water as Green Lubricants
by Ana Trajkovski, Nejc Novak, Jan Pustavrh, Mitjan Kalin and Franc Majdič
Appl. Sci. 2023, 13(13), 7413; https://doi.org/10.3390/app13137413 - 22 Jun 2023
Cited by 3 | Viewed by 889
Abstract
The study analysed the tribological performance of five different polymer composites: polyetheretherketone reinforced with 30% carbon fibres—PEEK CF30, polyetheretherketone reinforced with 10% carbon fibres, 10% graphite and 10% polytetrafluoroethylene—PEEK MOD, polytetrafluoroethylene reinforced with 25% carbon fibres—PTFE CF25, polyoxymethylene with 30% carbon fibres—POM CF30 [...] Read more.
The study analysed the tribological performance of five different polymer composites: polyetheretherketone reinforced with 30% carbon fibres—PEEK CF30, polyetheretherketone reinforced with 10% carbon fibres, 10% graphite and 10% polytetrafluoroethylene—PEEK MOD, polytetrafluoroethylene reinforced with 25% carbon fibres—PTFE CF25, polyoxymethylene with 30% carbon fibres—POM CF30 and ultra-high molecular weight polyethylene—UHMW PE. The polymers were tested under the sliding regime of a reciprocating stainless-steel ball on a polymer disc, with test parameters expected for hydraulic valves. Two environmentally safe lubricants were used: glycerol and water. The selected polymer materials and their tribological properties were compared based on the coefficient of friction and the specific wear rate. The worn surfaces were examined using scanning electron microscopy, and the transfer film was analysed using the energy dispersive spectroscopy technique. When tested in glycerol, a comparable and low coefficient of friction was measured for all polymers (~0.02). At the same time, a significantly lower coefficient was measured for all polymers in glycerol compared to water-lubricated conditions (~0.06–0.22). The polymers differed in the measured specific wear rate, which increases significantly in water for all polymers. A lower specific wear rate was measured for three polymers with higher microhardness: PEEK CF30, PEEK MOD and POM CF30. In water, PEEK CF30 showed superior tribological properties under harsh conditions but was well followed by POM CF30, which showed the most intense transfer film. Full article
(This article belongs to the Special Issue Research Progress on Hydraulic Fluid and Hydraulic Systems)
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