A general purpose engine friction model, based on lubrication theory was developed and is presented in this paper. The model takes into account the friction components of the complete ring pack, piston skirt, main/connecting rod bearings and valve train mechanism.
Using the developed model, it is possible to predict the complete engine friction (either in crank angle resolution or in engine cycle resolution (Friction Mean Effective Pressure, FMEP), the trajectory of moving components (e.g. piston secondary motion, journal movements in bearings, piston rings motion towards cylinder liner), the pressure field developed by the lubricant.
The model was used with data from a four-stroke medium speed marine diesel engine installed in the National Technical University of Athens/Laboratory of Marine Engineering test-bed. The effect of engine speed and engine load on predicted frictional losses was examined and compared with results obtained from other semi-empirical FMEP models.