The development of a simplified test rig for measuring the average friction torque of the piston-crank-slider mechanism of an internal combustion engine

The objective of this paper is to present a simplified friction measurement test cell for measuring the friction, developed on the main components of the piston-crank-slider mechanism of an internal combustion engine, including complete piston ring packs, piston skirts, connecting rod bearings and crankshaft main bearings. In detail, the main objective of this study was to measure average friction torque absorbed by an engine in motoring conditions. The proposed cell consists of an AC electric motor driving the piston-crank-slider mechanism of a typical, small, single cylinder, four-stroke engine. Several experimental runs were performed using this cell and the obtained results were compared with results from a detailed numerical engine friction simulation code, previously developed and published by the author(s) [Livanos et al]. Good agreement was found between simulation and experimental results, indicating that the proposed cell is capable of adequately predicting the dynamic friction behaviour of rotating and oscillating engine main components.