Decentralized Compact Hydraulic Supply through High-Speed Components

  Concept of a Flat Spool Valve

One obstacle to the use of electro-hydraulic axes (EHA) on mobile machinery is the power density that has been achievable to date using state-of-the-art technology. A decentralized hydraulic supply combines the advantages of a demand-oriented provision of hydraulic power at the consumer and reduced line losses. To increase the power density, a high-speed internal gear pump for an electro-hydraulic high-speed drive is being developed at ifas.

Benefit Procedure

Increase of the power density of electro-hydraulic drives through high-speed components

Development of a high-speed internal gear pump

Raising the speed level of hydraulic pumps

Efficiency studies of the internal gear pump

Decentralized EHA for mobile applications

Development of an EHA with high-speed actuator



+49 241 80 47746



Decentralized Compact Hydraulic Supply with High-Speed Components

In mobile machines, such as excavators, the hydraulic power is usually provided by a central pressure supply in the vehicle. This usually consists of one or more pumps. The operator can control the actuators of the working hydraulics with the help of valves. However, part of the hydraulic power is throttled off by the valve control and converted into heat. The hydraulic power is routed to the individual actuators by means of hoses and pipes. This again results in line losses. A demand-based power supply with a variable-speed drive reduces throttling losses. A decentralised arrangement of the power supply, directly at the consumer, minimises the transmission losses in the lines.


In this project, a functional model for an electro-hydraulic axis (EHA) with high-speed drive is being investigated. A high-speed internal gear pump is being developed for this purpose. Raising the speed level increases the already comparatively high power density of the hydraulic system, but also places high demands on the pump and the hydraulic system of the EHA. The aim is to increase the power density and compactness of the electro-hydraulic drive by means of high-speed components, thus making it attractive for use in mobile machinery.


Numerical Flow Simulation (CFD)

In order to optimize the operating behavior of the pump at high speeds, numerical flow calculations of the internal gear pump, so-called Computational Fluid Dynamics (CFD) simulations, are carried out at ifas.

Goals of the CFD simulation:

  • Understanding flow processes within the pump
  • Optimisation of the pump for high-speed operation
  • Design of the internal gear pump
  CFD Visualization of the Rotating Internal Gear Pump


External Gear Pump Section View of the High-Speed Internal Gear Pump

Within the context of this project, research is being conducted on a high-speed drive. For this purpose, an internal gear pump is being developed and subsequently tested. The system architecture of the EHA is adapted to the high-speed drive and the application in the field of mobile applications.


Electro-Hydraulic Axis (EHA) with High-Speed Drive

Compact Excavator with EHA Compact Excavator with EHA

The functional model of the EHA, including the electro-hydraulic high-speed drive, is being tested on a compact excavator. For this purpose the conventional stick cylinder will be replaced by the developed EHA. Testing on the vehicle is intended to demonstrate the feasibility of the decentralized drive concept.



Logo of the BMWi

The IGF Project 19224 N / 1 und 19224 N / 2 of the Forschungsvereinigung Forschungskuratorium Maschinenbau e.V. – FKM, Lyoner Straße 18, 60528 Frankfurt am Main was founded via the AiF as part of the Programme for the Promotion of Joint Industrial Research and Development (IGF) by the Federal Ministry of Economics and Energy based on a resolution of the German Bundestag.

  Copyright: © AIF   Copyright: © FVB

With the friendly support of

  • TwinMesh by CFX Berlin
  • BAUER Maschinen GmbH
  • Volvo Construction Equipment Germany GmbH
  • Hydac
  • Wilhelm Hoven Maschinenfabrik GmbH & Co
  • Eckerle Technologies GmbH
  • HydraForce
  • Bosch
  Logos of the Supporters Supporters of the Project


Schlussbericht Dezentrale kompakte Hydraulikversorgung durch High-Speed-Komponenten
Pietrzyk T. et al.: Design study of a high speed power unit for electro hydraulic actuators (EHA) in mobile applications, 11th International Fluid Power Conference, Aachen, Germany, 19-21 March, 2018, pp. 232-245