Measurement of piston / piston-ring friction and oil film thickness in an internal combustion engine

The work presented in this thesis is an experimental investigation of the lubrication of the piston/piston-ring and cylinder liner interface in internal combustion engines. It begins by identifying the relevance of such experimental work and reviews studies carried out by other investigators from the early 1900's to the present day. Following this, the development and testing of a capacitance based oil film thickness measurement system and a floating liner friction measurement system are descEibed in detail. The work carried out on the oil film thickness measurement system is an extension of an investigation by Grice (1990) who developed the system on a low speed engine simulator operating at room temperature. The floating liner friction measurement system was also developed on the same - apparatus under these operating conditions. The modifications required to a Petters AV3. LAB engine to allow the oil film thickness and friction measurement systems to be installed are described. Results from the oil film thickness and friction measurement systems obtained under motored conditions are presented and discussed. This is then followed by the presentation and discussion of measurements obtained under firing engine conditions. General conclusions drawn from these investigations are offered. Finally, recommendations for further work are suggested