Energy Comsumption of the Hydraulic Circuit of a Mid-Size Power Tractor

This work focuses on the hydraulic circuit that feeds the remote actuators of a mid-size power agricultural tractor. First of all, the energy consumption of a traditional load sensing architecture, which uses a single electronically controlled spool valve, is analyzed. For this kind of circuit, the position of the spool generally determines, at the same time, pressure drops both at the inlet and at the outlet section. The consequence is that in the majority of the situations both the meter-in and the meter-out configuration is not optimized in terms of energy consumption.An alternative architecture, with an independent metering configuration, based on a pressure based control strategy is analyzed and modelled. Energy consumption comparisons of the two systems are made, using different duty cycles, involving resistant and overrunning loads.