THE EFFECT OF THE ADDITION OF KEROSENE ON THE OILINESS OF LUBRICATING-OILS 260035

A report is made of the results of tests of the performance of oils diluted with kerosene in a journal-bearing friction-machine with regard to the so-called “oiliness” property of the lubricant, oiliness being defined as the property that causes a difference in the friction when two lubricants of the same viscosity at the temperature of the oil-film are used under identical conditions.

A detailed description is given of the method of procedure and of the precautions taken to keep the speed, load, bearing temperature, and oil-pressure constant throughout the duration of a run.

Four series of test-runs were made with the first test-bearing, the lubricant in the several runs being respectively a light mineral motor-oil, a blend of 35.75 per cent of kerosene with 64.25 per cent of cylinder stock, the light mineral motor-oil, as a check to see whether the conditions of the bearing had changed, and the light mineral motor-oil plus 2 per cent of oleic acid. The samples were chosen so that their viscosities were very nearly the same at the temperature of operation. The results are shown in the form of curves.

In tests made with a second bearing, spindle and cylinder stock known to be from the same crude were obtained, the oil used as a reference being a blend of these two and having a viscosity about the same as that of the light mineral motor-oil used in the first bearing. Oils showing the effect of the addition of kerosene were composed of the spindle and cylinder stocks blended with 10, 20 and 30 per cent respectively of kerosene, in such proportions that the viscosity of each of the three samples was the same as that of the reference oil. The tests showed that oils of wide difference in viscosity apparently have the same oiliness, whereas Kingsbury found that high-viscosity oils possessed the property of oiliness to a greater degree than oils of low viscosity.

The conclusion reached is that, when operating with kerosene blends, the fluid film apparently breaks down and unstable lubrication begins under less severe operating-conditions than when straight mineral-oil is used. This tends to show that under the conditions of these tests, the addition of kerosene decreases the so-called “oiliness” effect of the lubricant.