Oil-Flow through Crankshaft and Connecting-Rod Bearings

THE paper is limited to a discussion of the factors governing flow of the lubricant through the crankshaft and connecting-rod bearings. Apparatus for measuring the flow is described, and the fact that it permits measurement under operating conditions is emphasized. Results obtained by increasing main and connecting-rod bearing clearances are enumerated first. The paper then treats of the influence of engine-speed. Centrifugal force is shown to have a major influence on flow at high speeds, but it is pointed out that the magnitude of this influence can be controlled to a considerable extent by the radial location of the oil-hole in the crankpin.

The fact that the effect of changes in pressure differs with differences in engine-speed and oil-flow is commented upon, and a possible explanation for this condition is advanced.

Some results which at first appeared surprising were obtained in static tests in which the flow was measured at various crank-angles. The paper is concluded with a discussion of the probable explanation of these results and their significance.