Predefined tribological systems enable the designer of hydrostatic pumps and motors to leave the domain of
mixed friction contacts and obtain a new way of design. The locations of force conduction and gap sealings
evolve from incalculable subsystems into machine elements with predictable and computable properties.
The method is displayed and validated by the example of the RAC (radial piston machine) development and
leads to a novel concept for an axial piston pump and motor that promises a favourable efficiency chart and
excellent start-stop-properties (patent pending).

Continuously increasing demands for more powerful and more efficient hydraulic machines lead to a rising
complexity of these systems. Using model-based development methods is one approach to face this
challenge. This implies, that the entire development process, from the definition of requirements through to
the design, commissioning and operation of the system is supported by physical models. In this paper, an
overview about the enhancements arising from model-based engineering methods is presented. Therefore,
first methods focusing on the design/commissioning phase, which are already used within industrial
applications are presented. Afterwards, currently developed techniques aiming on the operation phase of a
system, which are enabled through the upcoming digitalization, are considered.

This article describes the analysis and selection of an electrohydraulic pump actuator by means of simulations in
order to optimize operation for any given hydraulic system. The focus is on developing a multidisciplinary
method of analysis. This involves interlinking various submodels such as the electric motor model, pump model
and cost model with a system model. With the help of this method, a large number of designs can be analyzed
automatically for the purpose of assessing the behaviour of the overall system. This delivers a preferred design
variant tailored to the customer’s requirements.

This paper elaborates on the use of virtual engineering methods such as Computational Fluid Dynamics (CFD), Finite Element Method (FEM) and system simulation to significantly improve the performance of hydraulic valves. The different simulation methods are used in conjunction to tackle the typical conflicts of goals in hydraulic engineering (e.g. pressure resistance vs. pressure drop). The approach is illustrated and the results are shown in two hydraulic valve engineering projects.