BMW rolled into town last night with a fleet of Hydrogen 7 sedans for us to test drive. Having already driven hydrogen cars from Honda and GM, we were intrigued to get behind the wheel of a hydrogen Bimmer, which differs from most other hydrogen-powered cars in that it doesn't rely on a fuel cell and electric drive train. Instead, it uses a modified version of the BMW 760Li's V-12 internal combustion engine to burn hydrogen in the cylinders in the same way as gasoline. It also differs from the pack in that that the hydrogen is stored in a liquid state rather than as a gas. Check out our gallery of the experience and more details on the car here.