Tests constant capacity pump considering the effect of viscosity and compressibility aerated oil

The paper presents mathematical models of the losses occurring in the pump with a theoretical capacity per revolution of the shaft and geometric (variable) performance on the rotation of the shaft. These models were used to laboratory testing and simulation energy losses in the pump to judge the energy efficiency of the pump and the efficiency of the hydrostatic drive. The results of research and analyses should be able to create and exploit the possibilities simulation programs support the process of designing hydraulic systems. Pursuing such programs will allow fast determination of the efficiency of the hydrostatic transmission with a positive displacement pump, composed of any item at any point of the fieldwork. These programs enable the selection of optimal in terms of energy, the operating parameters of the system. In an era of increasingly expensive energy, even a small reduction of losses can bring tangible economic benefits during machine operation. It is important to know the energy efficiency of the transmission, under not only nominal conditions, but also changes in the whole range of working conditions: the speed and load of the hydraulic motor, the viscosity of hydraulic oil particularly in the parameters or the longest occurring during operation. It is necessary, therefore, to design stage gear on a detailed analysis of energy enabling optimal selection of components and operating parameters of the system.