Comparative Analysis of Load Sensing and Common Pressure Rail Architectures in Hydraulic Excavators: Energy Flow Path and Fuel Economy

There is a growing focus on safeguarding the planet to limit the worsening of climatic conditions, global warming, and pollution in general. Every sector has been striving to move towards reducing energy and resource waste, thereby optimizing energy efficiency while performing the same operations. In recent years, this trend has also included the heavy-duty vehicle sector, which, due to limited alternative options and the difficulty of achieving the same performance with a minimal increase in costs, had remained more on the margins of the ongoing shift in approach. This study focuses on hydraulic excavators, analyzing one of the most promising proposals in the current landscape: the Common Pressure Rail (CPR) architecture in its hybrid hydraulic version, with a specific case study of a 9-ton excavator. The research begins with a careful analysis of the traditional architecture, optimizing its performance by developing speed controller for the actuators. The project then compares the conventional system with the new CPR system, studying their different behaviors in terms of energy efficiency and fuel consumption using the AMESim simulation environment and testing them on different specifically defined work cycles. A comprehensive approach is proposed, evaluating not only the hydraulic system but also how to achieve better results by optimizing the operating conditions of the internal combustion engine. This is accomplished through an analysis of the energy flow patterns in various subsystems, which helped focus attention on the parts of the system where the greatest losses occurred. The simulations confirm the theoretical potential of the CPR architecture, which proves capable of achieving the same performance as the traditional architecture while halving fuel consumption . The properly designed CPR architecture thus proves to be a valid alternative to conventionally used systems in hydraulic excavators, as it can perform the operations typically managed by a traditional machine, ensuring significant fuel savings, primarily due to its inherent greater energy efficiency and the ability to recover energy normally wasted in classic systems.