The German Aerospace Center has developed the Interurban Vehicle (IUV), a concept for middle and upper class vehicles.
It is five meters long, two meters wide and offers space for five people. The hydrogen fuel cell electric vehicle is designed to enable comfortable and emission-free driving over long distances of up to 1,000 kilometres.
By combining different lightweight construction approaches, the IUV with energy storage units weighs less than 1,600 kg when empty, the developers explain.
At the same time, it offers a very high level of safety, with autonomous driving functions.
For the project, we built the IUV as a prototype roll-up body. This prototype offers a first impression of what the vehicle might look like in practice. At the same time, thanks to the prototype, we were able to better develop the basic components and technologies, measure them and test them on test benches. It also shows which aspects we can further develop and realize in the future with partners from industry and research.
Sébastien Vohrer, project manager.
A lightweight vehicle structure is key to the concept to maintain low power consumption and long range.
The body of the IUV weighs only 250 kg, around a quarter less than what is typical for this vehicle segment.
To achieve this, different manufacturing methods have been applied. In addition, the body is largely made of fiber-reinforced plastic.
In some cases, aluminum structures or sandwich materials are also used, especially when the components must be very rigid and absorb a lot of energy during a crash.
Sandwich materials combine, for example, a fiber composite top layer with a lightweight plastic foam core or even durable materials such as balsa wood. According to the DLR, this structure makes them light and, at the same time, with very advantageous crash properties.
Whenever possible, DLR researchers worked with functional integration, another lightweight construction approach.
Hydrogen electric propulsion and intelligent energy management.
The IUV is designed as a fuel cell plug-in hybrid.
It combines a fuel cell with a power of 45 kilowatts, a hydrogen tank with a pressure of 700 bars and a battery with a capacity of 48 kWh.
With this configuration, the IUV has a total range of up to 1,000 km, according to the developers.
The electric motors, with a total output of 136 kW/185 hp, accelerate the vehicle up to 180 km/h.
The refueling process at a hydrogen filling station takes about the same time as conventional engines.
The battery can be charged separately. The fuel cell is located at the front of the car, the battery at the rear. The hydrogen tank under the vehicle contains approximately 7.5 kg of hydrogen.
The DLR has also studied the issue of energy management in depth. For UVI, researchers examined, among other things, metal hydride storage systems.
Thanks to this new type of storage system, part of the pressure difference between the 700 bar hydrogen tank and the 5 bar fuel cell can be used to generate additional cooling for the vehicle’s air conditioning and to support the conventional refrigeration machine.
In their work for the IUV, DLR scientists also investigated how autonomous driving would affect the concept and architecture of the vehicle. To do this, they assumed a high degree of automation (level 4). The car drives by itself all the time. Only when he can no longer handle a task does he ask the human to take over.
The IUV team developed several designs for this purpose and evaluated them for their functional and technical feasibility. One of the results is the seating arrangement of the IUV, which can be variably adapted to the driving style: the two front seats are rotatable. In stand-alone mode, occupants can also sit facing away from the direction of travel.
The air conditioning concept is tailored to the interior and the respective occupants. Each passenger can control the air conditioning individually via interfaces in the headliner.