Optimization of Directional Control Valves through Downstream Compensation Approach

Various academic studies show that in the use of common ICE Off-road Vehicles only about 10-15% of the available power at fuel level is actually transformed into useful energy for the actuators.Particularly the Directional Control Valves are responsible for the dissipation of about 35-40% of the hydraulic energy available at the pump level.The machine electrification trend makes it even more urgent to optimize the hydraulic system to ensure greater performance and higher battery autonomy.Traditional Directional Control Valves design solutions neglect important opportunities for reducing losses and improve internal regeneration. Especially, energy recovery is rarely applied and in any case by means of important superstructures which considerably increase the costs of the system.This paper presents an innovative Directional Control Valve layout, based on the Downstream Compensation approach that,in a simple and cost-effectivedesign, allows to recover a considerable amount of energy from both the inertial loads and the simultaneous use of multiple actuators at different pressure level.The proposed layoutperformance and efficiency arestudied through lumped element simulation and laboratory experimental tests.