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This study deals with the design of variable displacement oil pumps, with particular focus on wear of the inner components. A multibody model has been developed in order to achieve detailed knowledge on the dynamic loads which the main components are subjected to and to carry out a comparative analysis between different pump designs. A qualitative correlation, between the resulting wear following endurance tests and simulation results, has also been found. Design guidelines leading up to a good pump reliability have been obtained as a result of this activity.

In this work a lumped-parameter model, able to simulate the dynamic behavior of different types of valve train systems, was developed. Among the various aspects, the rocker arm flexibility, the valve lash, the possibility that the mechanical elements lose contact with each other and the possible impact of the valve in its seat were taken into account. The model includes two different descriptions of the valve spring, which can be schematized either by an ideal elastic reaction or by a multi-mass scheme, including the possibility of contact among adjacent masses.