TOKYO -- The redesigned Toyota Corolla, due to be launched in Japan this fall, is expected to be powered by the first in a family of new four-cylinder gasoline engines.

Toyota says its new 1.8-liter engine will be cleaner, more efficient and more powerful than its predecessor.

For example, Toyota says the engine will offer at least a 5 percent improvement in fuel efficiency compared to conventional engines.

Toyota builds 1 million of the current engines a year in plants around the globe. The new 1.8-liter engine will be the first in a family of engines that will range from 1.6 to 3.0 liters.

To raise fuel efficiency and cut emissions, the new engine uses Toyota's variable valve timing for both intake and output strokes -- known as Dual VVT-i -- and ultralight pistons. It also reduces friction by using roller bearings in the rocker arms.

To make the engine smaller and lighter, Toyota used a modular front section of the engine, which incorporates the water pump and chain cover. Aisin Seiki supplies the module.

Toyota also used smaller-diameter spark plugs to reduce engine size.

The engine will be built at Toyota's Shimoyama engine plant in Miyoshi, near Toyota City. Currently the plant manufactures 1.8-, 2.4- and 3.5-liter gasoline engines; a 3.0-liter diesel engine; and emission-control devices.