Imperial College London

Dr Tom Reddyhoff

Faculty of EngineeringDepartment of Mechanical Engineering

Senior Lecturer
 
 
 
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Contact

 

+44 (0)20 7594 3840t.reddyhoff Website

 
 
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Location

 

670City and Guilds BuildingSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Vladescu:2017:10.1016/j.triboint.2017.04.051,
author = {Vladescu, S and Ciniero, A and Tufail, K and Gangopadhyay, A and Reddyhoff, T},
doi = {10.1016/j.triboint.2017.04.051},
journal = {Tribology International},
pages = {140--153},
title = {Looking into a laser textured piston ring-liner contact},
url = {http://dx.doi.org/10.1016/j.triboint.2017.04.051},
volume = {115},
year = {2017}
}

RIS format (EndNote, RefMan)

TY  - JOUR
AB - This paper presents an experimental study into the flow behaviour of lubricant in a reciprocating contact simulating a piston ring–cylinder liner pair. The aim was to understand the effects of cavitation, starvation and surface texture, as well as the interaction between these, in order to improve automotive engine performance. A custom-built test rig was used, in which a section of piston ring is loaded against a reciprocating, laser-textured, fused silica pad representing the liner. A fluorescence microscope focusses through the silica specimen onto the contact in order to image the distribution of dyed oil. Tests were performed using a range of texture geometries and orientations, under starved and fully-flooded lubrication conditions, with measurements being compared against those from a non-textured reference.Under limited oil supply conditions, the non-textured reciprocating contact sweeps oil towards the reversal points (TDC and BDC), leading to starvation and increased friction. This issue is alleviated by the presence of surface texturing, with each pocket transferring oil from the inlet to the outlet of the contact as it passes; the result being 33% lower friction and oil distributed evenly over the liner surface. Even under fully flooded conditions, starvation is shown to occur following each reversal, as the change in sliding direction causes the cavitated outlet to become the oil-deprived inlet. This proof of cavitation-reversal-starvation, which occurs for up to the first 5% of the stroke length, depending on the lubricant’s viscosity, corresponds to regions of high wear, measured in this study and on actual cylinder liners reported in the literature. This process is also counteracted by the presence of surface texture, with each pocket depositing oil into the cavitated region prior to reversal.Fluorescence data also provides insights into other mechanisms with which different textures geometries control friction. Grooves oriented parallel
AU - Vladescu,S
AU - Ciniero,A
AU - Tufail,K
AU - Gangopadhyay,A
AU - Reddyhoff,T
DO - 10.1016/j.triboint.2017.04.051
EP - 153
PY - 2017///
SN - 1879-2464
SP - 140
TI - Looking into a laser textured piston ring-liner contact
T2 - Tribology International
UR - http://dx.doi.org/10.1016/j.triboint.2017.04.051
UR - http://hdl.handle.net/10044/1/48386
VL - 115
ER -