Energy Savings Assessment on a Mid-Size Excavator with Common Pressure Rail Architecture

In earthmoving machines, the prime mover transmits power to all actuators through hydraulic circuits. However, the use of flow control valves, which rely on pressure drops, leads to significant energy dissipation and fuel consumption. The shift toward electric propulsion, already in progress for mini excavators and expected to expand to larger machines, requires a sharp reduction in pump energy demand to match the operating range of diesel-powered vehicles. This study simulates the performance of a recently proposed hydraulic architecture, based on a validated model of a mid-size excavator. Instead of imposing flow to the actuators via proportional directional control valves, the proposed system uses two-position valves to independently connect each actuator to two constant-pressure lines maintained by hydraulic accumulators. A proportional valve is retained for fine speed control but operates with lower pressure drops, thereby improving overall system efficiency. The developed lumped parameter model preserves the original actuators and kinematics. Simulations reproduce dig-and-dump and levelling cycles, comparing fuel consumption against a Load Sensing system. Additional simulations reduce engine speed to increase efficiency, enabled by the greater flexibility in engine operation. Results show the proposed system can reduce fuel consumption by over 50%, demonstrating strong potential for enhancing excavator energy efficiency.