The Role of Soot Aggregation on the Lubrication of Diesel Engines

This paper deals with the role of the soot on the valvetrain wear in diesel engines. First, wear is related to the soot aggregation at the inlet, of the cam-tappet contact. Then, an experimental device using a Rayleigh pad which allows one to study the aggregation underflow of diesel soot in completely formulated oils is described. The results concerning four oil samples, chosen for their differences in formulation and aging are given and related to the wear. Finally, the aggregation is related to the interparticle interactions and, more particularly, to the dielectric constants of the soots and of the lubricant.