Mazda2 EV with a classic quasi-turbine
 

Mazda is testing a Mazda2 EV hatchback with a luggage-sized single-rotor 330cc Wankel engine. The compact range-extending 26 hp engine spinning at an optimum 2,000 rpms automatically recharges the system. Quasi-turbine/Wankel engines will be sadly missed because Mazda has declared they will not be developing any more primary rotary engines for future models.

Mazda 2 EV range extender prototype first drive Review | Autocar

Interesting and cool to see, but the engine kicks in at anything over 6 mph and runs continuously?!?!

That's pretty fascinating. I am surprised about the generator running all the time. It's a 20kwh battery pack, which should be more than sufficient for short distances. The ICE Mazda2 weighs about 2300lbs and they're saying this version weighs 2900lbs. I guess the weight gain isn't abnormal but it would be nice to see pictures of the rest of the setup. Including the rear mounted rotary.

Mazda needs to use this design for future models. They can make the economy cars silent and the sports cars noiser.

I like it, though I'm surprised they have the engine running at only 2000 RPM. My experience of owning one of the RX3s was that it's horrible at low engine speeds, especially when accelerating. Get it up to 4K RPM or more, and it was a great steady-state cruiser on the interstates (which I had to do for work back then).

It's optimized for low speed operation. So it's designed a little differently.

Heard from another source... Czech, so it could be woefully wrong... that the economy is just 4.9 l/100km. Have no idea if that's "combined" or "regen only". If it's regen only in the city, that's great. If it's combined, that's woeful.

And I was wondering how Mazda would integrate the Wankel into its SkyActiv philosophy...

Constant revs sounds wasteful but reduce the exciter voltage and you can turn down the fuel feed as the alternator load goes down to keep revs constant.

I've noticed in those many many BSFC maps that besides the ideal "island of efficiency," the fuel burn tends to be more efficient in that same rev range as the island. Makes sense to keep a constant speed.

I noticed the opposite, that the "island of efficiency" was noticeably wider (rpm) than it was tall (load), so that efficiency was more load sensitive than rpm sensitive, generally.

...still love the original zoom-zoom. http://www.youtube.com/watch?v=CRFSBZYI6j0

...and the legendary multiple rotors.
http://www.youtube.com/watch?v=6NckAj8YVXw

I seem to recall reading a few years ago that Audi was going to adapt this concept. I think it is a great idea. Build a simple, light, cheap series hybrid powered by an engine barely powerful enough to run it at cruising speeds. The weight/cost savings of not needing a monster sized battery pack easily pay for the engine.

I think the ultimate application would be to also have a direct mechanical linkage for highway cruising, sort of like the new Accord hybrid. This saves a good bit of efficiency over generating power to run a motor. The weight/cost is worth it, IMO.

This concept is what the volt should have been. The volt uses a much larger than neccessary engine.