Another key detail laid out in the patent is a rear-mounted transaxle - that is, a transmission and differential combined within the same housing - like the sort of setup used by some front-engine Ferraris and Porsches, not to mention Chevrolet Corvettes from the C5 through the C7. Putting the weight of the transmission at the rear of the car gives it better front-to-rear weight distribution for improved handling.

And a couple of different options for internal combustion engine are presented by the patent filing, as well: a Wankel rotary, and an unidentified V-configuration engine. Both seem almost equally likely, given that neither currently exists anywhere in Mazda's lineup. Nor do the rear transaxle, hub motors, or anything else detailed therein, for that matter.

Of course, just because Mazda has filed to patent the powertrain does not mean it will ever materialize in a production road car. If it does, the Mazda RX-9 could be a sports coupe worth waiting for.

