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Several methods are nowadays used by OEM’s in order to determine engine friction through experiments to help them develop friction correlations to be used in 1D simulation models. Some of the friction measurement methods used are; Willans Line, Morse test, Teardown test and Indicated Method. Each of these methods have their own disadvantages, with some reliant on heavy assumptions. In this paper a friction measurement method is discussed which requires a conventional motoring dynamometer cell by which the engine can be motored at different speeds. The exhaust manifold of the motored 2 litre, 4 cylinder diesel engine was shorted to the intake manifold with an unrestrictive ‘shunt’ pipe which reroutes the exhausted air to the intake [1]. The shunt pipe was pressurized by an external source of compressed air to make up for blow-by losses. It is noted that the compressed air supply is thus a small fraction of what would be required if no recirculation is used.

In the ever increasing challenge of developing more efficient and less polluting engines, friction reduction is of significant importance and its investigation needs an accurate and reliable measurement technique. The Pressurized Motoring method is one of the techniques used for both friction and heat transfer measurements in internal combustion engines. This method is able to simulate mechanical loading on the engine components similar to the fired conditions. It also allows measurement of friction mean effective pressure (FMEP) with a much smaller uncertainty as opposed to that achieved from a typical firing setup. Despite its advantages, the FMEP measurements obtained by this method are usually criticized over the fact that the thermal conditions imposed in pressurized motoring are far detached from those seen in fired conditions. In light of these considerations, the authors have put forward a modification to the method, employing Argon in place of Air as pressurization medium.