Walvoil told us about sustainability in the operation of machines

We met Walvoil al Bauma Media Dialogue. Monaco, a place of journalistic meetings and a sanctuary of efficiency, due to the abundant paradigm of loads and cycles in the application archipelago. For this occasion in Reggio Emilia, they wanted to create a narrative that was much closer to storytelling than just the presentation of the product, which also involves two well-known faces, Als and Exp.

Walvoil answers the question “Sustainability in the operation of machinery: a mantra, a must or a bogus?”

According to Walvoil, the modern machinery market requires a constant increase in productivity and performance, while lowering operating costs, greater efficiency and a reduction in emissions in favor of sustainability and social responsibility. This is shown by several surveys and studies in the sector up to 40 percent of the energy supplied to the hydraulic system of the operating machine is dissipated by the limited efficiency of the components and by the pressure drops generated for the purpose of regulating and controlling movements. The problem is all the more evident in electrified applications, where energy efficiency is synonymous with longer autonomy and reduction of battery capacity. Walvoil illustrates how to aim to increase the efficiency of the hydraulic system and its components with the possibility of reducing consumption by more than 20 percent.

Walvoil pursues this goal by acting in two ways:

  1. reduction of consumption and energy dissipation with Als systems (adaptive load sensing)

2. recover energy that would otherwise be lost, through Epx technology (Measuring out compensation).


Energy efficiency is achieved through an overall approach and strong electronic integration, which aims at the interconnection and coordination of specially designed components: pump, distributor, electronic control unit, operator interface.

Let’s start with the Als solution

Als is a synergistic set of components for the efficiency of mobile operating machines. The joint control of the hydraulic distributor and the pump makes it possible to reduce the pressure losses due to the pressure margins of the regulation system. At the same time, a number of logics are available that improve the machine’s control, productivity and driving comfort. Walvoil offers different Als solutions to offer extreme versatility and adapt to machine performance and plant engineering needs.
In fact, the Als system can be used as an integral part of the hydraulic distributor or inserted on the variable displacement pump.


ALS electronic flow sharing: This solution allows the realization of pressure control functions in combination with Flow Sharing distributors of the Dpx and Epx series. The system controls and conditions the circuit’s Load Sensing signal to reduce consumption and optimize control. Thanks to the possibility of integrating the Als system directly inside the distributor, the resulting advantages can also be used in combination with pumps with fixed displacement. In the case of using pumps with variable stroke volume, the ALS system further expands its savings and control options thanks to the control of the electronic control of the pump itself. Everything is controlled by an electronic control unit and by the software specially developed in the Phc Studio environment.

ALS Flow on Demand:

The special feature of this configuration is the combination of a normal open center distributor with electro-proportional control, with the electronically controlled variable displacement pump equipped with Als logic. The variable pump provides the flow rate defined according to the logic set by the operator through dedicated software, taking into account single or simultaneous drives. In this configuration, the Flow on Demand logic guarantees better load regulation and greater vehicle stability combined with a noticeable reduction in consumption.
The control of the electronic part is entrusted to the control unit with dedicated Phc Studio software.

walvoil sustainability

It’s Epx’s turn

The Epx series directional valves are a new series of electro-proportional control valves designed to allow control and recovery of hydraulic energy in mobile machinery.

The recovery takes place thanks to a specially designed compensator, which works in 2 ways:

by implementing an active type of recovery during simultaneous operation of multiple machine functions providing a passive recovery due to the entrainment loads, i.e. recycling the inertial energy which is usually dissipated through the lamination of the fluid towards the discharge.

With the energy recovered through an Epx series distributor, it is possible to:

  • Charge a set of batteries through a hydraulic motor connected to a generator + inverter
  • Make it available in the hydraulic system so that it can be reused by the machine functions
  • Store it in hydraulic accumulators

That distributor Exp was the subject of a paper entitled ‘Leading energy recovery strategies through advanced directional control valve’ presented at the 13th International Fluid Power Conference (IFK) in Aachen in June 2022, and the development of the project will be illustrated at the 2022 Ieee Global Fluid Power Society PhD Symposium, which will be held in Naples in October.

Take Als, take Epx, put them together and you will get…

Two very flexible technologies that can be combined and add their respective advantages. The many different configurations and the strong electronic integration make it possible to adapt the solutions to the most varied circuit configurations. Different levels of complexity and performance can be achieved thanks to the modularity of the Phc Studio software. Studies carried out and the use of Als on different types of vehicles show energy savings of up to 5 percent. The energy recovery potential of the Epx system is much wider, able to reduce consumption and return some energy with a total energy saving that, depending on the type of application, can reach 20 percent.

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