Measuring the tribological performance of all the tappets in a production engine using magnetometer sensors and the effect of lubricant rheology

Tappet rotation is one of the key tribological parameters that play an important role in component wear. Lack of available techniques has discouraged researchers from performing such studies on real production engines. In this research work, a novel experimental technique has been developed that allows the measurement of tappet rotation speed on any engine having direct acting tappets. This unique method does not require any changes or modifications to the components or engine itself. Using this innovative technique, for the first time, all the tappets of a single camshaft have been instrumented, and tappet speed was measured at different operating conditions verifying that not all the tappets behave in the same way. Experimental results clearly showed that all tappets do not respond to the change in lubricant viscosity and the direction of tappet rotation may be one of the factors influencing the performance. Copyright (c) 2014 John Wiley & Sons, Ltd.