TRANSFORMERS: configurable trucks for efficient transport.

Hybrid drive, e-mobility, energy efficiency, CO2 reduction, load volume sensor

Fig. 1: TRANSFORMERS trucks in trial operation, front: Load-optimization trailer, back: Hybrid-on-demand trailer (photo: Volvo).

The increasing freight traffic on Europe’s roads requires improvements in truck efficiency. In the EU research project TRANSFORMERS, an international consortium has taken on this task. As part of the collaboration, Fraunhofer LBF developed a sensor system for measuring the load volume and a battery housing to supply an electric auxiliary drive in the trailer.

The TRANSFORMERS trailers (Fig. 1) enable a reduction in the fuel consumption of up to 25%, particularly for palletized goods. This is achieved by the mission-specific adaptation of the structure, an electric auxiliary drive installed in the trailer, an adjustable loading capacity and holistically optimized aerodynamics.


The Van Eck load-optimization trailer has an electric roof height adjuster, a load volume sensor and a double floor system.
For example, if the maximum permissible mass of the trailer is reached without its volume being fully utilized, the roof can be lowered to reduce the aerodynamic drag.  The current utilization is determined in each case by the sensor system developed by LBF for measuring the load height (Fig. 2).
If, however, the maximum permissible mass has not yet been reached, pallets can be loaded one top of one another using the double floor system to fully utilize the maximum load height and thus increase transport efficiency.

Fig. 2: Sensor panel integrated in the Van Eck trailer for determining the load height and load volume (photo: Ursula Raapke, Fraunhofer LBF)


Zwei LKW mit langem Auflieger. Bei einem LKW ist die Ladungshöhe (Plane) am Ende flacher. Er ist nicht so viel beladen und kann seine Höhe anpassen.

Fig. 2a (online only): Determination of the load height (above) and adjustment of the roof height (below)


Fig. 2b: Loading example for the load volume sensor system (photo: Fraunhofer LBF)


Fig. 2c: Individual ultrasound sensor for determining the load height (photo: Fraunhofer LBF)


Fig. 3: Battery housing integrated in the Schmitz Cargobull trailer, shown from below (photo: Björn Mårdberg, Volvo)


Fig. 3a: Key components for integration in the battery housing (image: Fraunhofer LBF)


Fig. 3b: Arrangement of the various components in the battery housing (image: Fraunhofer LBF)



The Schmitz Cargobull hybrid-on-demand trailer has a manual roof height adjuster and a hybrid-on-demand drive with energy recovery. Similarly to the load-optimization trailer, the trailer’s roof height can be adjusted to the actual load height to reduce the aerodynamic drag.

As a commonly named hybrid-on-demand system, the electric drive-train installed in the trailer ensures additional power is available at short notice, e.g. for overcoming uphill gradients or when starting. Similarly, braking energy which is otherwise lost can be recovered on downhill sections of the journey.

The battery with associated power electronics and the necessary cooling system must be securely fastened to the underbody of the trailer during operation and must be protected from environmental impacts (e.g. stone-chipping) in harsh everyday use. The robust housing necessary for this has been designed and constructed at Fraunhofer LBF and constitutes a mechanically reliable connection to the trailer (Fig. 3).

Fig. 4a1: Maximum permissible mass – maximum aerodynamic drag.

Fig. 4a2: Adjustable loading capacity – up to 20% less aerodynamic drag

Customer benefits

The benefits of the concept lie in reduced fuel costs per ton-kilometer for the operator as well as lower CO2 emissions and a reduction in the risk of traffic jams on uphill gradients and in urban traffic.


Sponsors and partners

This project has received funding from the European Union’s Seventh Framework Programme for research, technological development, and demonstration under grant agreement no 605170.

The TRANSFORMERS consortium consists of the partners Volvo, Bosch, DAF, Fehrl, Fraunhofer IVI, Fraunhofer LBF, IFSTTAR, Uniresearch B. V., IRU Projects, P&G, Schmitz Cargobull, TNO, Van Eck and Virtual Vehicle Competence Center.

Further links to external pages:

Awarding of the European Transport Prize for Sustainability by HUSS-Verlag to the hybrid-on-demand trailer of Schmitz Cargobull:

European Transport Prize for Sustainability 2018: The winners of the truck bodies and trailers category: Schmitz Cargobull, “TransformerTrailer” project.
© Photo: Sandra Sommerkamp