VISCOSITY AND THE CONRADSON CARBON-RESIDUES OF LUBRICATING OILS

This paper deals with the relationship between the viscosity and Conradson carbon-residues of lubricating-oils for internal-combustion engines. Several curves are established using many grades of the same brands of oil while others are constructed to show this relationship with oils representing everything on the market.

Evidence is presented indicating that a true relationship does not exist between the viscosity at any temperature and the carbon-residue value, and sufficient data are presented to show in a general way what can be expected as to the carbon-residue value when the viscosity is known. Limitations are drawn showing which oils can be considered as being, from a carbon-residue standpoint, representative of good commercial products and further, those which have been subjected to drastic refining can be selected.