0

Full Content is available to subscribers

Subscribe/Learn More  >

Impact of Ageing on Tribological Properties of Environmentally Friendly Hydraulic Fluids

[+] Author Affiliations
Martin Schmidt, Hubertus Murrenhoff

Institute for Fluid Power Drives and Controls (IFAS), Aachen, Germany

Paper No. IMECE2002-39341, pp. 93-99; 7 pages
doi:10.1115/IMECE2002-39341
From:
  • ASME 2002 International Mechanical Engineering Congress and Exposition
  • Fluid Power Systems and Technology
  • New Orleans, Louisiana, USA, November 17–22, 2002
  • Conference Sponsors: Fluid Power Systems and Technology Division
  • ISBN: 0-7918-3631-2 | eISBN: 0-7918-1691-5, 0-7918-1692-3, 0-7918-1693-1
  • Copyright © 2002 by ASME

abstract

Hydraulic systems are used in many technical applications, e.g. in agricultural and forestry machines. Hydrostatic pumps and engines as well as hydraulic fluids are essential components of these systems. Thereof, the hydraulic fluids are of great importance since not only technical but also ecological requirements have to be fulfilled. Apart from fluid power transmission the most important technical function of hydraulic fluids is lubrication and the resulting reduction of friction and wear. In times when saving energy and resources have become environmental matters, lubricants are increasingly attracting public awareness. Important ecological aspects which need to be considered since they have a major impact on the application of technical products and decide about their success are biodegradability, water pollution and ecological toxicity. This is why ester based hydraulic fluids have started to substitute mineral oil based fluids. Additionally, ester based fluids have excellent tribological features due to the polarity of the ester molecules. However, ester based fluids change their physical and chemical properties due to usage. This paper will show that both the total acid number and the viscosity is increased by ageing while the level of additives and the viscosity index is decreased. Therefore, the impact of ageing on the tribological performance of an ester based hydraulic fluid will be analysed by friction and wear investigations. Exemplary, two tribological contacts are chosen: a mixed friction and an elasto-hydrodynamic contact. These are representative conditions for hydrostatic pumps and engines. Analysing the fluid’s behaviour being stressed by mixed friction is performed by using a tribometer. Investigating the ageing impact on elasto-hydrodynamic behaviour of the fluid, a bearing test facility is used. Finally, after having been dealing with tribological contacts used in hydrostatic machines the performance of a hydrostatic machine itself will be analysed. The impact of increased viscosity on friction which is generated within a hydrostatic gear unit at low speed will be discussed.

Copyright © 2002 by ASME
Topics: Tribology , Fluids

Figures

Tables

Interactive Graphics

Video

Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature

Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal

NOTE:
Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In