Mazda to bring back rotary engine as EV range-extender

The company plans to enter the EV market in 2020 with two new cars: one powered solely by battery and the other pairing an electric powertrain with a rotary engine that will be used to recharge the battery when necessary to increase the vehicle's driving range.

Although precise technical details have not yet been revealed, the engine is expected to be a variant of the Wankel rotary engine, a design in which the four strokes of an Otto cycle piston engine occur in the space between a three-sided symmetric rotor and the inside of a housing.

The key attraction of an engine based on this design is its high power to weight ratio – a characteristic that made it popular with designers of some of the first fighter aircraft - but its wider uptake has been hampered by maintenance issues and concerns over fuel and oil consumption.

Mazda claims that the relatively light weight and small size of a rotary engine make it ideal for a so-called shared packaging layout. It added that the engine will be able to run on liquefied petroleum gas and provide a source of electricity in emergencies.