Mitsubishi developing in-wheel motors for enhanced All-Wheel-Drive performance

Mitsubishi Motors released details of its ongoing development of in-wheel motors earlier this week, hinting that the company’s interest in next-generation electric vehicle technology offers highly promising potential in the ongoing evolution of Mitsubishi's all-wheel control technology. In other words, the company’s firebreathing Lancer Evolution XI or XII models, two or three years from now, might feature hybrid technologies not just for conservation’s sake, but for outright performance. The company statement stated, “an in-wheel motor makes it possible to regulate drive torque and braking force independently at each wheel without the need for any transmission, drive shaft or other complex mechanical components.”

Mitsubishi’s current Lancer Evolution IX high-performance 4WD sports sedan went on sale in Japan in March. With a 2.0-liter intercooler-turbocharged engine powering all four wheels through an electronically controlled 4WD system, the Evolution IX raises all dynamic performance parameters to a new level.

With the flagship GSR model priced at 3,570,000 yen (approx US$33,000), the Evolution IX is in its twelfth iteration in the series since it debuted in October 1992 and every year the car gets better, lavished with new levels of technology such as variable valve timing technology, titanium-magnesium turbocharger and the current model already features an electronically controlled all-wheel control component system – having an in-wheel motor would obviously move the system from passive to active and offer immeasurable benefits.

Mitsubishi Motors has chosen to centre its development of next-generation electric vehicle technology on in-wheel motors and on lithium-ion batteries that the company has been working on for several years.

Currently working on a test vehicle that utilises these technologies, which it has dubbed the Mitsubishi In-wheel motor Electric Vehicle (MIEV) concept, the company also envisages their application to hybrid electric vehicles and fuel cell vehicles.

The fact that the drive system is housed inside the wheel itself offers significantly greater design freedom and also makes it easier to locate such space-consuming components as the battery system, fuel cell stacks and hydrogen tanks used in hybrid and fuel cell vehicles.

Lithium-ion battery technology offers superior specific energy, specific power, and life over other types of rechargeable batteries and as such is expected to contribute to higher top speeds, extended cruising ranges and to greater weight reductions in hybrid and fuel cell vehicles.

Mitsubishi Motors has already started development and testing of the MIEV concept using a production compact vehicle, Colt, to serve as the rolling test bed. The Colt EV uses rear in-wheel motors powered by a lithium-ion battery system.

The company is also currently developing a more powerful in-wheel motor for use in a 4WD test car. The Colt EV will be on display at the "2005 Automotive Engineering Exposition" to be held at the Pacifico Yokohama Exhibition Hall, Yokohama from May 18 through May 20.

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