Environmental Engineering Reference
In-Depth Information
to carry even more batteries.The reason for that, of course, is that batteries
have only about 1 percent as much useful energy per pound as gasoline.You
cannot get the considerable advantages of electric propulsion without the
disadvantages of batteries. A better way to design for fuel efficiency is first
to make the car need only half as much power to make it go by making it
2-3 times lighter with the advanced polymer composite body.That results
in 2.5-3.5 times less air drag, which does not remove your stylistic flexi-
bility; it just means that things get smooth.
The first thing you do is make the underside of the car as smooth as the
top side, because the air doesn't know which side it is on. We have smooth
seams and so on, so the laminar flow adheres as far back as possible before
detaching into turbulent eddies.You have better tires that are small, hard, and
narrow, and you are not pressing down on them as hard, because the car is
lighter, but it will have just as smooth a ride. You also have very efficient
accessories.When you have in these ways made the car twice as efficient, then
you give it a hybrid electric drive, which means you run the wheels with spe-
cial electric motors, but you use a small engine turbine or fuel cell on board
to make the electricity from fuel as needed, buffering the electricity through
a small, high-powered storage device just to recover braking energy. The
whole power system is controlled by sophisticated software. You get much
more than a sum of the parts through this kind of whole system design.
If you just make the car ultra-light and slippery, you get an improvement
of a factor of 2 or 2.5 in fuel economy. Making it hybrid electric gives you
typically a 50 percent improvement, but both together give you improve-
ments of a factor from 3.5 to 5, then to 8, and then even more. So a six-
seat Taurus-class car, with no compromises, depending on your choice of
technology, will get from about 80 to more than 180 miles per gallon. A
four-to-five-seater will get from about 100 to 200
miles a gallon. Emis-
sions go down by a factor ranging from 10 to 1,000 or more.You can burn
any kind of fuel, and it becomes very convenient to burn compressed gases,
like natural gas or hydrogen, because a small, light, cheap tank will take you
a long distance if your car is this efficient.You can make the car as safe as
present models or safer, even in hitting heavy steel cars or sport-utility vehi-
cles. Because these ultra-light materials also can absorb 5-10 times the crash
energy per pound of steel, and do so more smoothly, the design and mate-
rials can overcome their mass disadvantage.
Because the car is slippery, it loves to go fast. Because it is ultra-light, it's
very agile. Because of the inherent engineering properties of the materials,
