Journal Article
Ultrasonic Imaging of the Piston Ring Oil Film During Operation in a Motored Engine - Towards Oil Film Thickness Measurement
2010-10-25
2010-01-2179
The oil film that forms between piston rings and cylinder liners is an essential parameter which influences parasitic loss and emission rates in an internal combustion (IC) engine. Several methods have been used to analyse these thin oil films in the past, however, all these methods have required invasive access to the contact area via a window or a surface mounted sensor in the cylinder wall or liner. This paper introduces a novel approach for the imaging of the piston ring - cylinder contact, non-invasively. A straight beam ultrasonic contact transducer was coupled to the wet-side of the cylinder wall of a motored diesel engine. Ultrasonic waves were propagated through the cylinder wall and reflections from the ring-liner contact were recorded as the piston rings passed over the sensing area.