Masahiro Moro, head of Mazda North America, has revealed the company's rotary engine will be used in Toyota's future autonomous vehicles.

In an interview with Bloomberg, Moro said Mazda's rotary engine technology would be used as a generator to charge the battery and extend the operating range of Toyota's self-driving electric cars.

This layout has been patented by Mazda and was last seen in the 2013 Mazda 2 RE prototype.

A similar setup is used in Chevrolet Volt, although the GM vehicle has a regular petrol engine. Compared to a conventional petrol or diesel engine, a rotary engine is more compact and has fewer moving parts.

“This is a very suitable engine to run a generator because it’s compact and lightweight, with no noise or vibration, and it has very good fuel economy," Moro told the business publication.

Mazda has talked repeatedly about continuing development of the rotary engine, but has yet to commit to a production vehicle using the technology. The last rotary-powered vehicle, the RX-8, went out of production in 2012.

Late last year, a rotary development vehicle based on the out-of-production RX-8 was spotted at the Nurburgring in Germany.

At this year's CES, Toyota unveiled the e-Palette autonomous car (above), which plugs into a cloud-based monitoring and control system, and can be programmed by its owner to perform specific tasks or behave in different ways.

According to Toyota's plans, the e-Palette will be available in a number of sizes, ranging from four to seven metres in length, and can be used for delivery and taxi services, or as a mobile showroom or business location. Toyota is partnering with Amazon, DiDi, Pizza Hut, and Uber as part of its self-driving car initiative.

Toyota currently owns a 5.25 per cent stake in Mazda, and has a number of joint ventures with the Hiroshima-based automaker, including joint development of electric vehicle technology.

Additionally, Toyota's hybrid technology is found in the domestic market 3 Hybrid, while the Mazda 2 sedan is sold as the Yaris iA in the USA. Most recently the pair announced they would build a new US$1.6 billion ($2 billion) plant in Alabama.