Improvement of the Operating Characteristics of Marine Low Pressure Hydraulic Machines

The subject of the presented research project is the exact knowledge about the parameters influencing the operating characteristics and limiting the maximum power of low pressure hydraulic vane type machines, used as drives for ship-deck machinery, to obtain a full utilisation of the potential of these motor type, and the intera ction between biodegradable hydraulic fluids and hydrostatic units of the motors. To improve the operating characteristics of this motor type, several measures, like the application of frictionand wear-reducing coatings as well as the fitting of synthetic or ceramic insets at the highly stressed contact areas shall be evaluated. The state of the art, concerning the influence of geometrical and physical parameters and the fluids properties on the total efficiency of hydrostatic motors is constrained on fast-moving devices or equations of general validity. For that reason a mathematical model of a low-pressure, slow-moving, high torque vane type motor was developed for the determination of volumetric and hydraulic-mechanical power dissipations. Knowledge about the behaviour of biodegradable hydraulic fluids, their influence on component wear and energetic efficiency of the motor and the change of fluid-characteristics and -performance under the special conditions of a ship-deck machine was obtained by bench-tests.