Effect of lubricant rheology and operating conditions on the rotating speed of all the tappets in a Mercedes Benz Engine

摘要

Engine valve train is one of the most difficult tribological components to lubricant effectively due to high contact stresses taking place at the cam and follower interface. The introduction of low viscosity oil for fuel economy purpose has further stressed the valve train components resulting in durability issues. One of the parameters that have a direct effect on the valve train performance and durability is the tappet rotation speed. Lack of reliable techniques resulted in researches and scientist performing experiments on modified test rigs. In this research work novel technique has been developed and implemented on Mercedes Benz OM646 engine figure 1, allowing for the first time, rotational speed measurement of all the tappets on a real production engine, thus providing a complete picture of the effect of engine operating conditions on valve train performance.