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Surprising Science

Super-Efficient Car Engines

A new Japanese internal combustion engine gets its high fuel economy of 70 m.p.g. from an improved gas engine and a lightweight design rather than hybrid technology.

“Next year, Mazda will sell a car in Japan that gets 70.5 miles per gallon, or 30 kilometers per liter. The fuel economy rating won’t be nearly this good in the United States because of differing requirements, but even so, the car will likely use about as little fuel as a hybrid such as the Toyota Prius—without that car’s added costs for its electric motor and batteries. The Mazda, a subcompact called the Demio in Japan and the Mazda 2 elsewhere, will include a package of changes that improves fuel economy by about 30 percent over the current model. These include a more efficient engine and transmission, and a lighter body and suspension.”


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