If we were playing alt-powertrain Bingo, a recent Mazda patent application filed in Japan would be one or two letters from victory. What's exciting about the patent, discovered by Japanese outlet T's Media via Motor Trend, is that while it makes a case for an internal combustion engine of any configuration, one of the drawings showing a rotary engine. The wild bit is that the whole powertrain comprises the ICE, a transaxle, two tiny in-wheel electric motors turning the front wheels, a third electric motor in the driveline, a capacitor, a lithium-ion battery, and three inverters. Motor Trend parsed the mechanics, and the way it reads, Doc Brown couldn't have done a better job.
The rotary engine at the front turns the rear wheels, but not directly. Instead of a flywheel on back of the engine, the drawing shows a 25-kW electric motor and an inverter, then a driveshaft running to the transaxle. Along the axis of the transmission tunnel in a normal car, between the inverter and the transaxle, lies a 3.5-kWh battery running at 48 volts. MT writes that the electric motor can add its output to the ICE output to drive the rear wheels, or the e-motor can turn the rear axle on its own.