Mazda rotary engine to return... in an EV


Mazda has officially confirmed that it will return the rotary engine to production, although it won’t be inside a svelte successor to the RX-7, but rather as the range-extender motor for an electric vehicle. Ok, so it’s not quite the role we’d been hoping for to mark the return of the Wankel, but there could be some good in this development. It means Mazda is invested in new rotary technology.

Yes, this rotary technology is focused on efficiency, because the role of a range extender is not to provide bucket loads of power but rather to quietly and smoothly get on with maintaining charge in electric batteries. But it at least means rotaries are back on the drawing board, which should help the case of insiders who are keen to produce a new rotary-engined sports car.

Mazda last teased the idea of such a product with its RX-Vision concept (pictured top) of 2015, a stunning two-door coupé that came with claims of significantly better fuel economy, lower emissions and vastly improved reliability compared to the firm’s last rotary motor, which was featured in the RX-8. At the time CEO Masamichi Kogai pledged: “One day rotary will make a comeback” as the main power source, so we can still live in hope.


Until then, however, it’ll live in an electric car, the first of which is expected on roads next year and will probably take the form of a crossover – because industry trends. Mazda says that its rotary range extender won’t just be useful to keep the EV’s batteries topped up, but that it can also be used as a reliable power source in times of energy cut outs, such as during Japan’s frequent earthquakes. Which is very cool.

So who’d have thought it? An engine design made famous for screaming the Mazda 787B to a Le Mans victory, that’s renowned as much for its thirst for oil as its revvy nature, could not only help to increase the uptake of electric cars but, quite possibly, also keep the essentials going in a house with no power. That’s quite some going.

P.H. O'meter

Join the PH rating wars with your marks out of 10 for the article (Your ratings will be shown in your profile if you have one!)

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
Rate this article

Comments (42) Join the discussion on the forum

  • V8 FOU 02 Oct 2018

    Sounds like a great idea. A rotary engine as a range extender has to be better than any of the present extender engines. Smoother, quieter, etc.
    Hope they have eliminated all the RX8 problems - although a lot of those were/are "self inflicted".

    Well done Mazda. Let's have an RX9 eventually too!

  • Max_Torque 02 Oct 2018

    V8 FOU said:
    Sounds like a great idea. A rotary engine as a range extender has to be better than any of the present extender engines. Smoother, quieter, etc.
    Hope they have eliminated all the RX8 problems - although a lot of those were/are "self inflicted".

    Well done Mazda. Let's have an RX9 eventually too!
    Sounds like a terrible idea in all honesty. I give it 3 years tops before it's quietly dropped and consigned to history!


    (the very idea of range extension is becoming less attractive as battery costs fall and energy density rises and charger power levels climb. Sure a rotary is smooth and quiet, for an internal combustion engine, but has terrible efficiency and adds a complex, expensive and support system(exh, cooling, fuel etc) intensive requirement to what, as an EV, would be a simple vehicle architecture. Most manufacturers are dropping Range Extenders in their new model line ups because once you have an EV that can do 300miles and charge at 125kW, well, what's the point?)

  • parkwaysc 02 Oct 2018

    Well The RAC and AA should be very pleased with this new offering from Mazda....

  • Mitch87 02 Oct 2018

    Max_Torque said:
    Sounds like a terrible idea in all honesty. I give it 3 years tops before it's quietly dropped and consigned to history!


    (the very idea of range extension is becoming less attractive as battery costs fall and energy density rises and charger power levels climb. Sure a rotary is smooth and quiet, for an internal combustion engine, but has terrible efficiency and adds a complex, expensive and support system(exh, cooling, fuel etc) intensive requirement to what, as an EV, would be a simple vehicle architecture. Most manufacturers are dropping Range Extenders in their new model line ups because once you have an EV that can do 300miles and charge at 125kW, well, what's the point?)
    I thought that rotaries were actually better efficiency when they could be tuned to run at a constant RPM due to their continuous motion not needing to accelerate and decelerate mass in the engine? A that their inefficiency when used in a more conventional engine setup was due to needing to be able to move through the rev range and inherently low torque requiring heavy fueling to get things going? So maybe they are ideal for a range extender? Plus they are small units! (Armchair engineers perspective here so might be way off! smile )

    edit: of course doesn't change that fact that a well sorted EV as you mention is just... simpler.

    Edited by Mitch87 on Tuesday 2nd October 10:59

  • mcdjl 02 Oct 2018

    Max_Torque said:
    Sounds like a terrible idea in all honesty. I give it 3 years tops before it's quietly dropped and consigned to history!


    (the very idea of range extension is becoming less attractive as battery costs fall and energy density rises and charger power levels climb. Sure a rotary is smooth and quiet, for an internal combustion engine, but has terrible efficiency and adds a complex, expensive and support system(exh, cooling, fuel etc) intensive requirement to what, as an EV, would be a simple vehicle architecture. Most manufacturers are dropping Range Extenders in their new model line ups because once you have an EV that can do 300miles and charge at 125kW, well, what's the point?)
    It gets around range issues. Extreme cases i know, but on 3 occasions this year (ok a Europe road trip) I did over 500 miles without more than a 5 minute toilet break. Each destination didn't have a charge point/capacity. Less extreme, i regularly drive around 150miles to places where i can't charge, unless i want to break the journey and spend an hour in the services each way then current electric is no use. I did look into an electric car: a ZOE is borderline justifiable as a commuting car on the fuel saved. I'd have to keep a second car though, so a range extended-plug in hybrid thats a sensible price would be great.

View all comments in the forums Make a comment