Quantification of energy savings due to the adoption of multi-pressure rail technology in an agricultural tractor: Implement system through experiments

Abstract

The Multi-Pressure Rail (MPR) system represents an efficient, pressure-controlled alternative to the often-inefficient flow controlled hydraulic control systems present in many agricultural vehicles. This work aims to expand on prior conceptual and simulation work by the authors on such a system by improving the generality of the system’s control scheme and further demonstrating savings potential through experimental validation. This is achieved through a novel form of the system’s core pressure level and mode selection logic that aims to reduce computational cost and improve scalability to implements with larger numbers of actuators. Two forms of this revised control logic are proposed, one prioritizing efficiency and the other prioritizing stability. The modifications necessary to convert the reference system into a full-scale prototype machine are then proposed, and this prototype is tested in an array of realistic operating conditions. From the tests performed on both the baseline system and the MPR solution it is found that the simplest controller strategy (Fixed HP MPR system) matches the dynamic performance of the baseline solution, while the more aggressive controller (Var HP MPR) does experience a slight reduction in dynamic performance. Both MPR systems achieve close to 50% power reduction and over 90% efficiency gain for the most common operating conditions of the reference vehicles, while around 40% power reduction and 65%–78% efficiency gain are observed at less common high-speed operating conditions.