Multi-domain optimization of directional control valve

Anže Čelik, Valve simulation expert, Poclain Hydraulics

Poclain Hydraulics, a world market leader for hydrostatic transmissions, strives to offer a complete solution for most-demanding applications. Since the last decade, hydraulic components and systems (especially those integrated in on-road or off-road applications) experience an increase of market needs and demands. Hydraulic valves are no exception here. Even more, due to space and weight limitations, hydraulic valves need to handle high power density at minimum overall dimensions. Rigorous operating conditions (e.g. high flow rates, high pressures) quickly leads to higher energy losses. Therefore, pressure drop, and weight optimization are only a few of the key factors. Such a valve is mainly used for off-road applications, such as drilling machines, crusher, mobile shredder etc. The presentation depicts the optimization path of directional control valves, using FEA, CFD and topology optimization. Several iteration loops have been performed to converge to the optimal solution (with respect to the pressure-losses, overall valve dimensions and weight). In the first step, internal valve geometry is optimised in order to assure lowest possible pressure losses, respecting casting procedure. Further, external valve geometry is optimised using a topology optimization process, which itself provides stress-free concentrations on optimised surfaces. Then, structural integrity has been proved by means of FEA. Finally, numerical investigations have been verified by experimental investigations (i.e. functional test, endurance test, pulsation test). They serve as final design checkpoint to prove overall valve integrity as well as to provide valuable feedback for CAE analysts to verify simulation approaches and corresponding numerical models.