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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.

Investigations into the performance of the parallel surface thrust bearing

Seymour, Douglas F. January 1954 (has links)
No description available.

The tribological effects of soot contaminated lubricants on engine components

Green, David January 2007 (has links)
The work in this thesis investigated the effects of soot contaminated lubricants of engine components. A thorough background review demonstrated that soot related wear is a major issue for the automotive and lubricants industry. A detailed analysis of the physical properties and effects of soot contaminated lubricants highlighted that there are associated effects that will tend to reduce engine perfonnance and efficiency. The actual wear that was produced is studied for the area of the engine which is most significantly affected by soot contamination, the valve train. A typical elephant's foot to valve tip contact, known to suffer from soot related wear, fonned the basis of the specimen ball-on-flat reciprocating wear testing. A standardised wear test rig and method were developed for the testing, which investigated different lubricants (base and fonnulated oil), increasing levels of soot contamination (using carbon black as a soot surrogate) and different temperatures. The results demonstrated significant increases in wear with increasing level of carbon black contamination. Furthennore, increased temperature tended to increase the amount of wear produced and using a fonnulated lubricant reduced the amount of wear measured when compared to tests using base oil. Significant changes in wear mechanism were visible from surface imaging ofthe wear scars, showing initially lubricated sliding, which changes to abrasion at higher contamination levels, and then shifting to contact starvation as the contamination significantly reduces the flow of lubricant into the contact at very high contamination levels. Significantly, the severity of the effects of soot contamination was due to the lubricant film thickness in the contact and therefore ultimately the lubrication regime within which it is operating. Where boundary lubrication is significantly affected by soot contaminated lubricants, but these effects are reduced when the contact operates under elastohydrodynamic (EHD) lubrication conditions. A region of the engine that is significantly affected by soot contaminated oil is the contact between the piston and the cylinder wall or liner. This is mainly due to the component's proximity to the area where soot in produced. Wear will occur in this highly sensitive region due to the breakdown of the protective oil film, which will occur when the lubricant is contaminated with soot. A method of analysing the effect sO~as been investigated 'using an ultrasonic technique to measure the oil film between a piston and a cylinder wall or liner. The ultrasonic oil film thickness measurement technique (developed at the University of Sheffield) has been used in many static and dynamic applications; therefore an initial trial was performed on a single cylinder engine, demonstrating some success. A motored test engine was then built on which to develop the technique and to provide a platform for future research. The test engine demonstrated potential for future success, as a variety of ultrasonic transducers were tested. Testing also highlighted that significant future work, regarding reducing electrical interference, improving the data processing electronics and further investigations into the different types of transducer is required to improve the technique.

Transient analysis of isothermal elastohydrodynamic point contacts

Jalali-Vahid, Davood January 2000 (has links)
No description available.

Application of electrochemical techniques to tribology

Xu, Xiaoyin January 2004 (has links)
No description available.

Top ring zone oil sampling in gasoline engines

Pease, Nick January 2001 (has links)
No description available.

Investigation of succinimide dispersants and their interactions using reduced total oil volume lubricant degradation

Sutton, Michael Robert January 2000 (has links)
No description available.

Transient ultra-thin lubricating films in circular point contacts under combined viscous, molecular and surface force actions

Alsamieh, Mohamed Fahmy Abd January 2002 (has links)
No description available.

Mapping shear stresses in elastohydrodynamic lubricated contacts

Grieve, Robert Simon Angus January 2004 (has links)
No description available.

The Lubrication of High Speed, Gas Turbine, Roller Bearings

Ford, R. A. J. January 1975 (has links)
No description available.

Hydrodynamic pressure and oil film thickness between piston ring and liner

Brown, S. R. January 1977 (has links)
No description available.

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