New Engine Boosts Gas Mileage

Toyota Motor Co. said Monday it will begin selling cars this year with a new engine that improves fuel efficiency by at least a third by running on a leaner mix of air to gasoline.

Toyota is expected to sell cars powered by the new 2.0-liter engine, called the D-4, in Japan this year but other details, like which models will come equipped with it and whether they will be available in the United States, were not provided.

Toyota said it had developed a device that allows the engine to run on an air-fuel mix that is three times leaner than conventional engines. The company said automatic transmission vehicles using the D-4 have at least 30 percent greater fuel efficiency than vehicles with conventional engines.

The development means that a model that averages 35 miles per gallon could improve to 45 mpg with the new engine.

Mitsubishi has said it plans this year to roll out models in Japan with similar technology. It will follow next year in Europe.