Temperature Prediction of Displacement Controlled Multi-Actuator Machines

A promising technology for the advancement of fluid power systems is displacement controlled (DC) actuation. The main advantage of DC actuation is that metering losses are completely eliminated by replacing each actuator's proportional valve with a variable displacement pump and controlling the actuator motion by pump displacement. This technology can achieve up to 50% energy savings when compared to the conventional load sensing (LS) systems and the elimination of metering losses in DC systems is directly translated in lower heat generation. This paper presents a model to predict the thermodynamic behavior of multi-actuator displacement controlled machines. A complete mathematical model has been developed based on conservation of mass and energy. The model characteristics are discussed for an excavator, which contains four variable displacement pumps, three single-rod actuators, a rotary actuator for the slew, a gear pump, an accumulator, a heat exchanger, a reservoir, as well as metallic hydraul...