BMW Hydrogen 7. Photo Credit: BMWThis is not a concept car. BMW Hydrogen 7, based on the BMW 7 series and powered by a hydrogen combustion engine, has gone through the complete process of series development.
BMW Hydrogen 7 has gone through exactly the same all-round series development process as every new model from BMW. New components such as engine technology, the tank system and vehicle electronics for hydrogen drive have all been developed in and through BMW's usual Product Creation Process, each and every component therefore having been examined and verified with utmost precision, ensuring that it meets all the requirements of series development.
The engine, suspension and body of this new model are based on the overall vehicle concept carried over from the BMW 760i and BMW 760Li Saloons. At the same time BMW Hydrogen 7 features a dual-mode twelve-cylinder combustion power unit able to run on both hydrogen and conventional gasoline. Maximum output is 191 kW/260 hp, accelerating BMW's Hydrogen Saloon to 100 km/h in 9.5 seconds. Top speed of BMW Hydrogen 7, in turn, is limited electronically to 230 km/h or 143 mph.
The dual-mode combustion engine represents the core of BMW strategy to use Hydrogen. Without the slightest delay or change in driving behavior, the innovative V12 switches over from hydrogen to gasoline drive.
While the use of fossil fuels inevitably results in carbon dioxide emissions, hydrogen as an alternative source of drive energy is extremely friendly to the environment, developing nothing but vapor in its process of combustion.
Liquid hydrogen as fuel
BMW prefers liquid hydrogen over gaseous hydrogen because of its greater energy density. With a fuel tank taking up the same space and providing the same capacity, the amount of energy contained within cryogenic liquid hydrogen exceeds that of hydrogen stored in compressed gaseous state at 700 bar by more than 75 per cent. This gives a vehicle running on liquid hydrogen a correspondingly longer cruising range.
BMW Hydrogen 7. Photo Credit: BMWIn the hydrogen mode BMW Hydrogen 7 is able to cover a distance of more than 200 kilometres or 125 miles, with another 500 kilometres or 310 miles in the conventional gasoline mode.
BMW has overcome all the challenges associated with the use of use of liquid hydrogen as a fuel. Since hydrogen under normal ambient pressure has to be cooled to - 253 °Celsius in order to turn into a liquid, innovative vacuum super-insulation is required to store hydrogen fuel in the car over lengthy periods.
The hydrogen tank in BMW Hydrogen 7 has double walls with several layers of aluminum and glass-fiber in the space in between measuring 30 millimeters or almost 1.2 inches in thickness in order to avoid higher temperatures entering the tank.
A vacuum in the intermediate section between the two walls avoiding any kind of airborne heat transfer and the mounts holding the inner tank in position are made of carbon-fibre-reinforced plastic bands reducing thermal conductivity to a minimum.
The super-insulation that results equals the insulating effect of a 17-metre-thick layer (56 feet) of styrofoam. Filling hot coffee into the tank, for example, you would have
to wait approximately 80 days until the coffee has dropped to a temperature suitable for drinking!
Filling up the car with liquid hydrogen has been made very easy. The process has been completed automated and takes 8 minutes. All the driver has to do is press a button in the cockpit next to the steering wheel.
Elaborate hydrogen monitoring and safety equipment ensure the use of liquid hydrogen poses no additional risks.
The BMW Hydrogen 7 has undergone a complete program of crash tests going beyond the usual legal requirements.
These crash tests include frontal offset collisions in accordance with EURO NCAP at an impact speed of 64 km/h or 40 mph, rear-end collisions with 100 and 40 per cent overlap, as well as side-on collisions at the car's most sensitive point directly on the fuel filler pipe.
To ensure optimum safety in even more extreme accident scenarios, the hydrogen tank was even tested under truly exceptional conditions such as exposure to flames, firearm shots, massive mechanical damage, as well as the reaction of the fuel tank and safety equipment to a loss in insulating vacuum. In an additional series of tests, tanks filled with hydrogen were fully encompassed by flames at a temperature of more than 1,000 °C (1,830 °F) for up to 70 minutes. Even under such conditions, tank behavior did
not present any problems, with the hydrogen in the tanks escaping slowly and almost imperceptibly through the safety valves.
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