Examination of Micro Groove Bearing for Aluminum Block Engine

Abstract

In the crankshaft bearing part of an aluminum block engine, the clearance changes depending on the temperature due to the difference in the coefficient of thermal expansion between the aluminum block and the forged crankshaft. In order to react to the change in the oil clearance due to temperature variation, the author has tried to apply Micro Groove Bearing (MGB) with excellent running-in characteristics using a 4L V8 gasoline engine made of aluminum block. The results show that the best specification of MGB has been 2.5-3.0μｍ in depth and 0.15-0.25mm in width and the engine starting friction at -30℃ has been 90-160 Nm and the crankshaft friction has been about 40% of the total friction. No damage has been found in the test bearings for the revolution speed of 1000-4000r/min. under full load.