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Variable-displacement lubricating pumps are an attractive solution for reducing fuel consumption and emissions in motorcycle engines. In this prospective, modeling and experimental analysis are very useful means for a deeper understanding of pump operation and for effectively implementing pump control. Zero-dimensional simulation results of a 7-vane pump were compared with the experimental data of dynamic piezo-resistive pressure transducers fitted into the casing of a pump prototype, which was operated under steady-state conditions at different rotational speeds and eccentricity values. The experimental data exhibit oscillations which were explained by taking into account the pressure transducers dynamics, as a result of the transducer location in the pump casing, of the air dissolved in the hydraulic fluid and of the geometry of the tubing/transducer system.

A zero-dimensional dynamic model was developed in the Matlab/Simulink® environment to predict the behaviour of a variable-displacement lubricating vane pump for internal combustion engine applications. Based on the geometric and kinematic characteristics of the pump, the model allows predictions of the pressure evolution in each chamber of the pump and in the delivery piping, by employing an integrative-derivative approach. Simulation results were compared with experimental data of pressure transducers, which were fitted along the periphery of the pump case and in the delivery channel. The analysis of the experimental data shows that the pressure dynamics, which is experienced by the transducers, is in some cases quite different from the pressure dynamics in the pump chambers and produces pressure peaks which are not actually present in the original signal. The pressure transducers output was then also modelled in order to properly compare simulation results and experimental data.

The paper illustrates a zero-dimensional dynamic model which was developed in the MATLAB®/Simulink environment to predict thermal transient of an automotive cooling system. In particular, the rapid switch-off of an internal combustion engine which was operated for a prolonged time at high speed under full load was investigated. In this condition, significant vapour formation and, consequently, pressure rise within the cooling circuit can arise, because of the sudden heat transfer from the high temperature head metal to the coolant contained in the cylinder head passages. The proposed model allows predictions of the vaporized mass of coolant as well as of the pressure evolution within the cooling circuit. The simulations results were compared with experimental tests carried out on a production 4-cylinder, MPI small S.I. engine, 1.2 dm3 displacement, and the agreement was very satisfactory.