Synergetic utilization of hydraulic, electric and electrohydraulic drive and control systems in agricultural vehicles Embedding hybrid technologies on mobile machines

摘要

Although hydraulic power technology is still dominant in agricultural vehicles, hybrid and electric drive and control systems are an obvious trend. These are mostly seen as a substitution possibility for mechanical and hydraulic units especially putting forward efficiency improvements by electrification. This approach by itself neglects the possibilities and potentials of a combined and synergetic application of hydraulic, electric and electrohydraulic technologies. By applying a synergetic approach one can take the individual technologies' benefits and deficits under consideration resulting in an overall optimized system. Benefits of hydraulic components and actuators are e.g. a high power density, high force and torque levels, simple realization of linear movements, good availability due to mass production, high reliability and an integrated cooling. Electric components and drive units stand out by high dynamics, good controllability, simple distribution of power and a high integration level. Finally, electrohydraulic power units enable a customized decentralization and flexible design of drive and actuator systems already combining both domains [1]. The approach presented focuses on a synergetic use of hydraulic, electric and electrohydraulic units for auxiliary functions on agricultural machines such as actuation of sowing or planting functions, loading doors, sprayer arms, forager spout, header adjustment and others. The basis for the current development are hydraulic-electric generators enabling an efficient transformation of hydraulic to electric power at different power levels. The paper at hand demonstrates how electric power is subsequently available for, both, electric drives and electro-hydraulic power packs, which, on the one hand, can be designed for their specific application and, on the other hand, can supply the right amount of power to individual system areas reducing parasitic losses.