Study of the performance of the hydraulic circuit of an agricultural machine with a lumped parameter approach

The entire hydraulic circuit of a mid size power agricultural machine (New Holland T6000 of CNH Industrial) has been studied in this paper using a lumped parameter approach, in Siemens LMS AMESim® environment. The analyzed circuit has been split in two main units: the fluid power supply unit and the high pressure circuit with users. The first one converts the inlet mechanical power into hydraulic power, while the third one converts hydraulic power in mechanical power. Each unit has been separately modeled and validated comparing the simulation data of each block with the experimental data provided by the manufacturer. The proposed target of each simulation has been achieved with a good accuracy. The model has been run in several tests where the load has been modeled using a valve and an orifice with fixed section. Tests have been run combining the fluid power supply unit and the high pressure circuit with users. In the final model, the priority valve has been modeled using three different loads called Load 1, Load 2 and Load 3. Each load simulates a user, therefore Load 1, 2 and 3 are respectively the steering, the trailer brake valve and the rest of the circuit. The model demonstrates that it is possible to predict, in a simple way, the real working conditions of the hydraulic circuit. This research has demonstrated that the study of hydraulic circuits of agricultural machines using a lumped parameter modeling approach is a valid instrument that can help engineers to design new solutions for energy saving or power management of complex machines.