Mapping the tribochemical films across the cam profile when lubricated with oils containing MoDTC-type friction modifier

Yasir Al-Jeboori*, Shahriar Kosarieh, Ardian Morina, Anne Neville

Institute of Functional Surfaces (iFS), School of Mechanical Engineering, University of Leeds, LS2 9JT, UK

 *Corresponding author: mnyaa@leeds.ac.uk

Abstract:

The novel aspects of this study involve the mapping of the tribochemical films formed across the camlobe and correlating this to the wear profiles (using ASTM 6891-09a standards) which were observed with contacting Taylor Hobson talysurf. Tests were performed on a Single Cam Rig (SCR), taken from 1.25L FORD Zetec (SE) engine. Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray (EDX), Raman spectroscopy, X-ray Photoelectron Spectroscopy (XPS) and Focused Ion Beam (FIB)/ Transmission Electron Microscopy (TEM) analyses were all performed on the tribofilm to understand the tribochemical interactions between oil additives and the cam/follower interface. Results showed that chemistry of the tribofilm derived from camlobes was seen to be varied as a function of tappet coating, tappet thickness and cam profile.