Ultrasonic Piston Lubrication Monitoring and the Effects of Distortion and Deterioration

Lead Research Organisation: University of Sheffield
Department Name: Mechanical Engineering

Abstract

Modern design of automotive engines focuses primarily on raising efficiency to meet increasingly stringent legislation on vehicular emissions. A viable route for this is to study the oil films between interacting components to optimise the film thickness. This leads to reductions in frictional losses through the powertrain which in turn raises the overall efficiency. Research into automotive lubrication encompasses numerous other aspects of engine design that affect efficiency primarily being; lubricant deterioration, surface geometry, bulk structural deformation and surface specification.
This project is aimed to develop a series of sensing techniques to study the oil films formed in various contacts in internal combustion engines. This is achieved by the design and assembly of an electric motor driven engine that allows for the effect of degraded lubricant and component distortions to be studied. With the potential to incorporate the most promising techniques into a fired engine.
These films are being researched using ultrasonic transducers that are based upon the piezoelectric effect. The base principle for a longitudinal piezoelectric transducer is based upon a reflection of an ultrasonic wave from a change in medium that the wave is propagating through. The time in which it takes for a signal to be pulsed and received can provide the distance the wave has travelled and therefore thickness of a medium. Similar approaches can be used with shear transducers to quantify the oil viscosity. The most beneficial characteristic of these sensors is their non-invasive nature. That the surface either side of the oil film being considered does not require direct modification that most alternative approaches require. This therefore enables films closer to real world applications to be developed in motored rigs compared to their invasive method counterparts.
The automotive oil films are studied using longitudinal and shear wave piezoelectric transducers in conjunction with methodologies previously developed by the Leonardo Centre for Tribology at the University of Sheffield. An example of a contact of interest is the piston ring-liner contact. This can be studied by the instrumentation of piezoelectric transducers on the thrust, anti-thrust and neutral sides of a cylinder, which can provide data on; piston tilt, lubrication regime, cyclic variation and performance of each ring.

Publications

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Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/R512084/1 01/10/2017 30/09/2022
1947853 Studentship EP/R512084/1 01/10/2017 30/09/2021 Jack Rooke