Design and development of an optical research engine for the fundamental study of piston-ring lubrication phenomena
File(s)
Author(s)
Elekima, Omoni Watson Lulu Star
Type
Thesis
Abstract
Lubricant across the piston ring liner contact is essential for reducing friction and wear within the contact. However, the lubricant could seep into the combustion chamber and cause problems such as pre-ignition and knock. This project investigated the transport and interaction of oil across the piston cylinder liner contact of an internal combustion engine using a combination of different techniques. An optical engine was designed and manufactured to provide optical access for full stroke visualisation of the piston. The optical engine enabled the use of optical investigative methods such as LIF. The optical engine was embedded with capacitance sensors in the cylinder liner to measure oil film thickness. The combination of the techniques helped to understand the behaviour of the lubricant at both the piston ring cylinder liner contact and on the piston land. This provided 3D insight into lubricant behaviour using the 2D view of the LIF images and the 1D data from the film thickness measurements. The oil film thickness was higher on the upward strokes of the engine cycle than the downward strokes. The pressure behind the second piston ring was measured. It was observed that the pressure behind the second piston ring reduces with an increase in engine speed and there was a correlation between pressure behind the ring and measured film thickness. Higher pressure behind the ring was associated with smaller film thickness. A high-speed laser induced fluorescence technique was used to visualise the piston-ring area. At almost all conditions, higher fluorescence intensities were observed beneath the oil control ring. The recorded intensities seemed to show a circumferential flow pattern and respective velocities were estimated.
Version
Open Access
Date Issued
2023-05-31
Date Awarded
2024-04-01
Copyright Statement
Creative Commons Attribution NonCommercial Licence
License URL
Advisor
Aleiferis, Pavlos
Sponsor
Engineering and Physical Sciences Research Council
British Petroleum Company
Publisher Department
Mechanical Engineering
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)