Automakers explore gas-saving technology

By Steve Kichen

updated 3:04 p.m. ET March 30, 2008

It was not that long ago that U.S. motorists were paying $1 for a gallon of regular gasoline. Today, the auto industry and outside researchers have a big incentive to explore energy-saving ideas that they would have considered zany just a few years ago.

Automotive history is ripe with tales of inventors with promising new engine technologies who were never able to bring their "ideas" to market. This time, maybe one or two of the ideas that follow will actively deliver a breakthrough.

Ethanol injection
One of the most promising new ideas in energy efficiency comes from researchers at the Massachusetts Institute of Technology. The proposition: get more power and efficiency out of turbocharged motors by injecting ethanol, methanol or E85 (85 percent methanol, 15 percent gasoline) into the engine at times of higher demands for power.

The MIT crowd claims this technology can boost gas mileage by as much as 30 percent, and that it allows a high-compression engine and high-boost turbocharger to operate on regular gasoline. Daniel Cohn, senior research scientist at the MIT Laboratory for Energy and the Environment, and other MIT professors, have formed a company, Ethanol Boosting Systems, and are testing their concept with Ford Motor.

Casey Selicman of CSM Worldwide, an automotive research and consulting firm, explains, "With aggressive turbocharging, you get a heavy case of knocking if you try to use regular fuel." The direct injection of ethanol into the combustion chamber has an evaporative cooling effect and eliminates the knocking.

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Ethanol Boosting Systems thinks it is possible to get as much as 330 horsepower and 360 foot-pounds of torque from a 1.9-liter engine using regular-grade gasoline as the primary fuel. For comparison, Volkswagen's state-of-the-art two-liter, turbocharged direct-injection four-cylinder delivers 200 hp and 207 foot-pounds of maximum torque — and requires premium fuel.

Whereas the average turbo installation costs manufacturers an additional $1,000, Ethanol Boosting Systems estimates that their system would run a total of $1,400 to beef up the engine and add a second fuel-injection system, plus a small (4- to 6-gallon) secondary fuel tank for the "boost fluid."

Cohn says that the additional manufacturing cost for a turbo diesel is $5,000, and a diesel motor — unlike ethanol boost — requires advanced exhaust treatment. This technology is mostly theoretical, but not that different from the common practice of injecting extra gasoline into a conventional turbo engine to cool the combustion chamber, rather than power the motor.

Gasoline tech, meet diesel
On another front, Daimler and General Motors are experimenting with motors that run on gasoline but combine features of traditional gasoline engines (fuel ignited by a spark) and diesel technology (fuel ignited by compression of fuel and air).

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