Session: Pumps 2

Paper Number: 113450

113450 - Combined Pump and Compensator Margin Control for Pre-Compensated Load Sensing Architecture: Implementation and Experiments 

Load sensing (LS) is a predominant hydraulic control system architecture for mobile fluid power systems in agricultural and other off-road applications.  LS systems provide good flow control to multiple actuators supplied by a single pump, minimize load disturbances, and provide a compromise between cost and energy efficiency.  However, this load independent feature is typically realized with compensator valves, thus a significant portion of available hydraulic power is used for control by maintaining a constant pressure drop across the actuator control valves.  This article details experimental development, implementation, and testing of a control strategy known as hybrid variable margin (HVM) on the pre-compensated LS system of a large row-crop tractor.  HVM consists of an electronically controlled variable-displacement pump replacing the traditional pump as well as introducing an electronic proportional pressure-reducing valve (ep-PRV) in the pilot line of the local pressure compensators (LPC).  This gives the flexibility to control the pressure differential across the control valves as well as varying the pump margin to suit the operating conditions. Experimental tests and development of the control strategy will be detailed in this paper.  When operating one hydraulic function, effective power savings averaging 10.4% was seen across all test conditions, and an average efficiency gain of 13.3% was realized when compared to the traditional LS system.  Multiple functions are also tested.  These results are compared against predictions from a high-fidelity simulation of the hydraulic circuit.  Dynamic performance of the HVM solution is also analyzed and compared against the traditional LS system.

Presenting Author: Patrick Stump CNH Industrial

Presenting Author Biography: Patrick Stump is a Ph.D. Candidate at Purdue University under Professor Andrea Vacca and an Electro-Hydraulic Controls Engineer at CNH Industrial. His research focuses on experimentation of novel hydraulic control architectures for agricultural applications with the aim of improving system efficiency and performance under real world operating conditions.