New awd Toyota Prius not U.S.-bound, for now

TOKYO -- The fourth-generation Toyota Prius went on sale in Japan today, complete with a new all-wheel-drive version arriving just in time for the onset of snowy driving.

Toyota expects to sell as many as 28,800 awd variants a year in its home market. But don’t expect them stateside anytime soon.

Despite the increasing popularity of awd passenger cars in the U.S., a trend tapped by rivals such as Subaru, Acura and Audi, Toyota is still unconvinced Americans want an awd Prius.

The world’s largest carmaker also hasn’t tested the system, dubbed E-Four, in the extremely frigid conditions typical of northern states, let alone Arctic frontiers such as Alaska.

Back home, Toyota’s engineers spent six years assessing demand and testing the system in Japan’s northern regions, where snowfall can be tremendous but temperatures more mild.

The company is studying a possible U.S. launch, but nothing has been decided, E-Four engineer Yoshihiro Ikushima said at a test drive. Prius sales are typically concentrated in sunshine states such as California where all-wheel traction is a low priority.

In Japan, Toyota expects to sell 144,000 units of the new Prius a year. About 10 to 20 percent will be E-Fours.

The feature tacks on an extra 180,000 yen ($1,462).

The system, which includes a second motor, inverter and drive shaft, also adds 154 pounds.

While the system is similar to the electric awd systems used in the Lexus RX and Toyota RAV4 crossovers, the power is way different. While the crossovers get a 50-kilowatt motor, the Prius hatchback gets one generating a modest 5.3 kilowatts.

In the awd Prius, the car always starts from a standstill in four-wheel mode. It shifts to front-wheel drive for cruising. But when it encounters snow or other slippery conditions, the back wheels click on again to provide additional control.

The system can automatically distribute torque between the front and rear wheels for optimal stability, but it doesn’t vector torque between the left and right wheels.

The E-Four setup is one of many new technologies Toyota is packing into the next Prius, which executives hopes will win new customers with styling and performance, not just fuel economy.