EXPERIMENTAL STUDY OF THE ELECTROHYDRAULIC REMOTE SYSTEM OF AGRICULTURAL TRACTORS FOR IMPROVED ENERGY EFFICIENCY AND CONTROLLABILITY
energy consumption is known to occur in agricultural tractors. Tractors are
state of the art machines engineered to output high power quantities, resulting
in high fuel consumption. Fuel consumption is a great concern on these complex
machines. The quantification of energy loss within the hydraulic systems of
tractor working cycles is an important step that will lead the development of
current technologies with performance and cost effective solutions.
In this work, the state of the art load sense technology implemented in an agricultural tractor will be studied with the goal of understanding key points where excessive energy loss may occur. The reference machine, a New Holland T8 390 category 4 tractor has been fully instrumented to make measurements of power within its high pressure hydraulic systems. A custom built DAQ system with National Instruments hardware and software acquired data. The machine has a pre-compensated load sense hydraulic system architecture. This work details specifics of load sense systems in general and also those to the reference machine. The particular focus of this work is to test energy efficiency and behavior of the Electro-Hydraulic Remote valves [EHR valves] located in two different high pressure circuits. This work will detail the rationale for developing an experimental test plan that was based on input from performance standards in tractors and knowledge from expert operators and farmers. The experimental characterization of the EHR valves demonstrated internal system behaviors that the EHR valves have. It helped identify the most favorable working conditions at which EHR could achieve at least 80% efficiency. Furthermore, scenarios where EHR valves may have low performance or unwanted behavior were also tested. These conditions yielded values as low as 53% efficiency. Solutions to flow saturation scenarios were implemented to assure functionality at lower speeds in the implements of the tractor if a saturation scenario was met. With the study of this work, potential technologies may be implemented in the EHR valve circuits to further increase efficiency.