What is a fuel cell hybrid vehicle

August 03, 2005 at 12:42 pm

Researchers combine fuel cells and hybrid drives and avoid emissions

Anyone who knows the small electric vehicles from Hotzenblitz probably knows that they have to fill up with electricity in order to stay mobile. The prototype called Hylite now shows how that can be changed. The German Aerospace Center (DLR) developed the car in collaboration with several auto suppliers. The ultra-light Hotzenblitz served as the basis.

Fuel cell hybrid drive
The Hylite is a so-called fuel cell hybrid vehicle. That means: The car does not fill up with electricity like the Hotzenblitz, but with hydrogen. From this, the Hylite uses fuel cells to generate electrical energy that feeds an electric drive. This principle makes the car emission-free, because the "exhaust gas" in the fuel cell is exclusively water. In the miracle cell, there is no real combustion as in normal gasoline engines, for example. Instead, the hydrogen reacts electrochemically with the oxygen in the air. This is much more controlled The nature of the reaction means that no by-products are formed.

Variable working pressure
A special feature of the Hylite is its low-pressure fuel cell system. It works at a maximum pressure of around 2.2 bar. This pressure only comes about when the car is currently in need of maximum power, otherwise it is lower. The variable pressure increases the energetic efficiency. Another innovation: previously, hydrogen and air had to be specially humidified before the gases flowed into the fuel cell. Thanks to the use of fuel cell stacks with direct water injection, this technically complex solution could be dispensed with.

Completely different type of hybrid vehicle
Strictly speaking, the Hylite is a hybrid vehicle. This designation stands for cars that have two drives. With the Hylite, however, the term has a completely different meaning than with the hybrid cars that are already on the market. In the Toyota Prius, Honda Civic IMA and Lexus RX 400h, a normal gasoline engine works hand in hand with one or two electric motors. The Hylite also has two drives, so to speak. Because in addition to the fuel cell system, the car has a traction battery. When braking, the prototype converts the kinetic energy into electrical energy, which can then be fed into the battery. This energetic surplus can be understood as a second drive source - in this respect, the term hybrid vehicle has its justification.

Storage capacity is to be improved
For the future, the project group wants to further improve the metal hydride storage system developed for the Hylite for use in cars. Above all, the storage capacity should be even higher. In any case, the Hylite is another step towards the future. And in the opinion of many experts this is called hydrogen in automotive engineering.
(sl)

Picture gallery: Research Hylite