R. Wayte

Bio: R. Wayte is an academic researcher from Imperial College London. The author has contributed to research in topics: Piston ring & Diesel engine. The author has an hindex of 2, co-authored 3 publications receiving 438 citations.

The Measurement and Study of Very Thin Lubricant Films in Concentrated Contacts

Abstract: Optical interferometry is now a widely used technique for measuring the separating film thickness in model rolling and sliding elastohydrodynamic contacts. There are two limitations of the method as conventionally employed: first, it cannot easily be used to accurately measure films less than one quarter the wavelength of visible light, i.e. less than about 100 nm. Secondly, only certain, discrete thicknesses, spaced at least 50 nm apart can be determined. This paper describes work aimed at overcoming these limitations so as to make optical interferometry applicable to the study of boundary or very thin film elastohydrodynamic lubrication in rolling contacts. A combination of a solid spacer layer with spectrometric analysis of reflected light from the contact enables very thin lubricant films to be accurately measured. The approach is applied to the study of thin films formed in rolling contacts by low viscosity lubricants. Some anomalies in the relationship between film thickness and speed are found with...

Measurement of Piston Ring and Land Temperatures in a Firing Engine Using Infrared

Abstract: Sapphire windows have been inserted in the liner of a single cylinder, 550 cm3 capacity, diesel engine to enable temperatures of piston lands and rings to be monitored during firing. The overall temperatures thus measured are comparable to those reported in the literature obtained using embedded thermocouples. However, the very fast response time and surface specificity of the infrared method have also enabled transient temperature changes which take place just after combustion to be observed. Presented as a Society of Tribologlsts and Lubrication Engineers paper at the STLE/ASME Trlbology Conference in St. Louis, Missouri, October 14–16, 1991

Paper V (ii) Piston Ring Face Temperatures in a Firing Diesel Engine

Abstract: A set of sapphire windows have been inserted in the cylinder liner of a Petter AVI diesel engine. This has enabled the temperatures of the piston ring and piston land surfaces to be measured at various points in the cycle of a firing engine using an infrared emission microscope attached to a storage oscilloscope. In this paper the method is described and some results obtained at mid-stroke and top dead centre are presented. These are compared to previous measurements of the bulk temperature of piston rings taken by other workers.

The Development of a Spacer Layer Imaging Method (SLIM) for Mapping Elastohydrodynamic Contacts

Abstract: Optical interferometry has proved to be a valuable experimental tool in the study of elastohydrodynamic lubrication (EHD). It is a technique that gives detailed information on the lubricant film distribution within the contact; however, the sensitivity is limited and it is only recently, with the development of the spacer layer optical technique, that the study of the thin film lubrication regime has been possible. The limitation of the spacer layer technique is that generally only one measurement is taken from the center of the contact. The next logical step in the development of this technique is, therefore, a system that combines the mapping capabilities of the original optical method with the thin film capabilities of the spacer layer approach. This paper describes the development of a contact mapping technique that uses the spacer layer approach to visualize, and measure, thin lubricant films in concentrated contacts. The development of the technique is described and its application to both static an...

Mechanism of Action of Colloidal Solid Dispersions

Abstract: In the past there has been considerable interest in the possibility of using liquid lubricantscontaining dispersed, solid particles in the 1–50 micron size range to reduce friction andwear. These particles are used in greases and some industrial oils. Researchers are nowdirecting their attention to the behavior of much smaller colloidal particles in the rangeof 5 nm to 200 nm diameter. Such systems are formally known as ‘‘colloidal sols’’ andhave been claimed to influence friction and wear. Further reasons for studying suchcolloidal particles is that they are present in soot-contaminated engine lubricating oils, aswear debris and as partially-soluble additives. Thus, the objective of the work derived inthis paper was to investigate the mechanism of action of colloidal solid particles in therange of 5 to 200 nm diameter in lubricating oils. Of particular interest was the effect ofslide-roll ratio on particle entrainment and the influence of the ratio of particle diameterto elastohydrodynamic lubricant film thickness on particles’ behavior. This study hasshown that in thin film contacts, colloid nanoparticles penetrate EHD contacts mainly bya mechanism of mechanical entrapment. It is found also that in rolling contacts at slowspeeds, colloids formed a boundary film of at least 1 or 2 times the particle size. This filminfluence friction and wear. However, this film is lost at high speed and the film thicknessreverts to the colloid-free fluid. The results of this study have enabled a mechanism oflubricating action by colloid sols to be derived. @DOI: 10.1115/1.1537752#

The measurement of lubricant–film thickness using ultrasound

Abstract: Ultrasound is reflected from a liquid layer between two solid bodies. This reflection depends on the ultrasonic frequency, the acoustic properties of the liquid and solid, and the layer thickness. ...