BMW has announced that it has developed a second-generation of its Hydrogen 7. The original Hydrogen 7 — which BMW began leasing to high-profile clientèle in 2006 — could run on both hydrogen and gasoline, but the latest iteration will only run on hydrogen.
Unlike typical hydrogen vehicles from General Motors, Toyota and Honda – which use a hydrogen fuel cell to convert hydrogen into electricity — the BMW Hydrogen 7 combusts hydrogen in the same way that a gasoline engine would. The Hydrogen 7 even uses a version of the 6.0L V12 found in the road-going 760Li, which allows for the capability to run on either hydrogen or gasoline.
However, because the Hydrogen 7 uses hydrogen in the same way a normal car would use gasoline, it requires the hydrogen to remain in a liquid state. This requires a 30 gallon tank that can’t get any warmer than -423°F. And because the tank of liquid hydrogen builds pressure when not in use, the system has to vent once the tank hits 87 psi. That means that a Hydrogen 7 will have a bone dry tank after sitting for 10-12 days.
The first-generation Hydrogen 7 only returned about 4.7 mpg when running on hydrogen and 19.5 mpg — highway — on gas. BMW claims a hydrogen range of 125, with another 300 miles being supplied by the 19.5 gallon gas tank.
But BMW says that the hydrogen-only version of the car will show improvements in range and performance, although BMW has yet to release any performance numbers. BMW is expected to give full details on the latest Hydrogen 7 when it is shown at the 2008 National Hydrogen Association Conference and the 2008 SAE World Congress.
