Calculation of crank train friction in a heavy duty truck engine and comparison with measured data

Abstract

This article describes measurements and calculations of friction losses in the crank train of an IVECO heavy duty truck engine. The main objectives were to quantify the effect on friction of variation in lubricant viscosity and to demonstrate the ability of CAE tools to predict friction at contacts in the crank train. Results of various measurements of friction are described. Cycle-averaged whole engine friction was derived from measurements of cylinder pressure and brake torque. In addition a motored friction teardown test was performed to separate the losses from different engine systems. Commercially available analysis tools were used to calculate friction at contacts in the crank train under the same conditions as the tests and this article describes key assumptions and input data and presents calculated results compared with measured data.