Leno on Hydrogen Fueling Our Future: Jay's Green Garage
January 1, 2008 4:24 PM
By Jay Leno
Published in the January 2008 issue of Popular Mechanics.
Today, the automobile is under attack from people who believe that it's the major cause of all our environmental woes. But it's not the car. It's the fuel. The residual gases, mainly CO2, produced from burning fossil fuel in internal-combustion engines are to blame. Fortunately, many modern cars don't have to run on fossil fuels.
While most automakers are experimenting with potential solutions, such as hybrids and electric cars, that would drastically change the automotive landscape, BMW is pursuing a simpler solution: Use hydrogen to power a good old internal-combustion engine.
Think about it. Modern IC engines run smoothly, they're powerful and, if they're not 100 percent dependable, they're darn close to it. So why push this technology to the side and start over again with, say, a hybrid or electric car?
I recently spent 10 days driving around in BMW's Hydrogen 7, a standard 7 Series sedan equipped with a 6.0-liter V12 engine that's been modified to run on either gasoline or hydrogen. Unlike a fuel cell vehicle that converts H2 to electricity, the 7 actually burns it just like gasoline. The hydrogen is stored as a supercooled liquid in an insulated tank located behind the rear passenger seats. (The tank is so well-insulated that if you put a scalding cup of coffee in there in mid-September, it would still burn your lips at Thanksgiving dinner!) All that insulation keeps most of the hydrogen at a chilly minus 423 F. But a small amount of H2 is constantly "boiling off," or vaporizing. When the car is not running, the excess gas is mixed with oxygen and vented into the atmosphere. When the car is running, that excess vapor is forced into the vehicle's intake manifold, where it's mixed with air and injected into the engine's cylinders to be burned.
One of the main benefits of using hydrogen is easy to explain. A few years ago, I was asked to give an automotive talk at Paramount Studios. First, I drove a hydrogen-powered car onto the stage, placed an empty glass under the tailpipe and let the car idle. As I spoke, the glass filled with water, the byproduct of burning this fuel. When I finished, I picked up the glass and drank the liquid. It wasn't the best-tasting water, but there was nothing wrong with it. And that's the point: What came out of the car was harmless.
Of course, there are disadvantages to hydrogen. For one thing, there's that venting issue. If the car is a daily rider, there's no problem. But if you fill it with hydrogen and go away for a couple of weeks, your tank will probably be empty upon your return. Availability is also an issue. The infrastructure just isn't there to support a mass rollout right now. Where would the cars refuel? BMW sent people to my garage to fill the tank for me.
We're at the same crossroads today as in 1907: What fuel should we go with? One hundred years ago, there was steam, gasoline, diesel, electricity and even ethanol. The only fuel we didn't have was hydrogen. Obviously, gasoline won out.
These days, steam is not taken seriously as a power source, gasoline is in question, diesel and ethanol are making a comeback, electric power is being considered and now we have hydrogen in the mix. Which fuel will emerge victorious? Probably the one that comes with a mass marketing plan, and gets to the people fastest and cheapest.