When trial testing begins in a few years, Toyota's versatile E-Palette could potentially have a tiny rotary engine on board as a range extender for the model's electric powertrain. The combustion mill would boost the boxy model's range, so that the machine wouldn't sit at charging point out out of commission for such a long time.

In its announcement for the E-Palette, Toyota listed Mazda as one of its initial partners on the project, which also included Amazon, DiDi, Pizza Hut, and Uber.

"Mazda will provide technical information on a [rotary engine] range extender to be used in the vehicle being developed. We will reveal more details at an appropriate time," Mazda spokesperson Jacob Brown told Green Car Reports.