In-axle motors are coming in even when only one traction motor is used and this is part of a bigger picture spanning light commercial vehicles and even large industrial vehicles though here we see great interest in near-wheel motors with no axle and to some extent in-wheel motors. Whereas batteries are stuck with lithium-ion technology for the coming decade, even as motors proliferate, there remains a healthy contest between asynchronous (AC induction), switched reluctance synchronous, permanent magnet synchronous and intermediate options.
For example, a synchronous reluctance and a PM motor are the basis of IFEVS four wheel drive microcars in Italy. Asynchronous was considered to be the big, reliable but poorly performing and relatively inefficient "washing machine" option but they are standard on Tesla cars with ludicrous mode, a Canadian performance motorcycle announced this year, Continental boost starter generators for 48V mild hybrids and in an increasing number of other vehicles, particularly buses.
The motor technology contest shows that there are many more gains to be made with motors and related power electronics.
We are moving on in both format and location from Toyota's Aisin making sophisticated transmission-integrated motors and motor-generators for the successful Prius. For example, Dana's new e-axles for electric transit buses and city delivery vehicles launching in 2018 will feature a fully axle-integrated motor and gear box sold as one item. They will supply appropriate product whether one or both axles are electrically powered in this way. Fuel economy is one gain from dispensing with heavy in-board mechanical drives in this way. Several percent: another multiplier.
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