Measurement of the crankshaft seals friction losses in a modern passenger car diesel engine

This paper presents results of experimental investigations on the friction losses of the crankshaft radial lip seals of a modern four-cylinder diesel engine for passenger car applications. A two stage strip-test has been conducted on a motored engine test bed to obtain the friction torque of the radial lip seals. For the experimental investigations with the crankshaft seals removed from the engine, a special sealing apparatus has been designed and built. A wide range of tests have been performed covering the full speed range of the engine at lubricant temperatures of 70 celcius, 90 celcius, and 110 celcius. The results show a dependency on crankshaft speed and engine media supply temperature but also revealed the presence of constant plateaus of friction torque over engine speed.