Autos: Going the Extra Mileage

Inside Ford Motor Co.'s cavernous wind tunnel, a thin stream of smoke glides gracefully over the new Lincoln Zephyr. But what catches the eye of aerodynamic engineer Wayne Koester is a tiny somersault of smoke just where the back window hits the trunk. "Do you see that?" he says, pointing from behind the control-room window. "That's turbulence." And turbulence is the archenemy of aerodynamics. Koester tried to persuade Lincoln's designers to lower the trunk to improve mileage. But they balked, saying Lincoln's customers demand a big trunk to haul golf clubs. The result: the Zephyr gets 45kpg on the highway--1.6kpg less than its sister car, the Ford Fusion.

These days, though, mileage misers like Koester are gaining traction in Motown. With oil prices high and likely to go higher, Detroit is painfully rediscovering the eat-your-peas merits of fuel economy. General Motors and Ford combined to lose $5 billion in their auto operations in the third quarter as gas prices skyrocketed: concern about mileage has jumped into the top five reasons shoppers reject a car, according to new research from J.D. Power.

So the race is on to reverse a 20-year slide in fuel economy in American cars. In wind tunnels and R&D labs, engineers are chiseling away at cars to make them "slippery." And they're overhauling the century-old internal-combustion engine and transmissions to squeeze out a few more mpg.

The latest trend is to shine a spotlight on the guts of upcoming models, rather than just their curvy exteriors. Ford recently unveiled a new V-6 engine and six-speed transmission that it says will improve fuel economy by 7 percent. GM is touting its own fuel-saving six-speed, and Chrysler just introduced its new Caliber small car with a transmission that continuously, but imperceptibly, modulates gears to boost mpg by 8 percent.

The breakthrough making the most noise is actually a retread of an innovation that failed a generation ago. Over the past 18 months, Chrysler, Honda and GM have introduced engines in which half the cylinders shut off at cruising speeds, boosting mileage by as much as 12 percent. GM tried shutting down cylinders to save gas 25 years ago, after the last energy crisis. But the infamous Cadillac "8-6-4" engine was a disaster, prone to leaking oil, rattling the steering wheel and breaking down. Today's GM engineers replaced the old clunky mechanical controls with electronics that calibrate every fraction of a second whether to run on full or half-caf. "We sell 1.8 million of these engines a year," says GM engineer John Rydzewski. "That's huge fuel savings, enough to cover every single hybrid ever built."

Another promising fuel-saving technology is continuously variable transmission (CVT). CVTs boost mileage by as much as 10 percent by replacing the traditional transmission with a belt-and-pulley system that constantly adjusts to an infinite number of gear ratios to maximize fuel efficiency. While some drivers gripe that CVTs are noisy and can give cars a bad case of the shakes, Chrysler and Honda are introducing new CVTs tuned to feel more natural (read: like a regular transmission). And the search is on for the holy grail of engine enhancements: firing the motor without spark plugs. That might sound like a goal only a gear geek could love, but such an engine would burn fuel more cleanly and efficiently while boosting fuel economy by 30 to 40 percent. Honda is tantalizingly close to developing one; GM also expects to have a running prototype within a few years. Detroit can only hope that such advances smooth out its recent bumpy ride.