YPSILANTI, MI – Toyota says the next-generation Prius hybrid will be more fuel-efficient and ride on an all-new, more rigid platform.

The upcoming Prius, which will replace the current third-generation model on sale since 2009 in the U.S., will have "significantly improved" fuel economy beyond the current's 50-mpg (4.7 L/100 km) average, Satoshi Ogiso, Toyota managing officer overseeing the new Prius, tells media at a Toyota hybrid media event here.

Ogiso promises a lighter-weight Prius that is roomier and employs smaller electric motors. He says Toyota is planning to use smaller, more compact components. The gasoline engine also receives attention, with 40% thermal efficiency, compared with the current Prius' 38.5%.

Toyota hints the next Prius will debut in 2015, noting there has been six years between generations up to now. The next iteration of the plug-in hybrid will be developed in parallel with the standard hybrid model.

Ogiso says Toyota will consider the current Prius PHEV owners' desire for greater electric range, which presently is below 15 miles (24 km), depending on the battery’s state-of-charge and other conditions.

Additionally, the auto maker says it is developing a wireless, or induction, charging system for the next PHEV.

Toyota also announces a "well-defined" midsize sedan concept of its long-awaited fuel-cell car will debut at the Tokyo auto show in November, followed by the U.S. Consumer Electronics Show in Las Vegas in January.

Details are scant, but Ogiso says the hydrogen fuel-cell stack currently is developing 3kW per liter of power density. "We believe that's a world's best, and about twice that of the fuel-cell stack we have been using in the Highlander fuel-cell hybrid vehicle."

cschweinsberg@wardsauto.com