Julian Rendell
21 November 2013

What is it?

A Mazda 2 supermini re-engineered as an electric car and powered by a 20kwhr, 346 volt lithium-ion battery pack fed by a range-extender rotary petrol engine and generator.

Mazda already has a Mazda 2 electric vehicle in use in Japan, so the range-extender is an incredible elegant engineering solution that shoe-horns the compact rotary engine powerpack under the hatchback’s rear boot floor.

The combustion engine is a single rotor of 330cc swept capacity designed to operate at a constant 2000rpm, when it pushes out a modest 26bhp.

To maximise space utilisation, the rotary engine is mounted horizontally under the rear boot floor together with its fuel tank and generator. This sub-assembly is incredibly compact, and looks like it would fit in a large suitcase.

The battery pack is arranged under the hatch’s main floor from where it feeds energy forward to the 100bhp electric motor, regulator and controller mounted in the engine bay.

Given the modest battery-pack capacity, Mazda’s range-extender is designed to cut in at a relatively low 6mph and to run continuously.

Of course, there is a weight penalty for carrying around all this technology. And whereas a base-spec Mazda 2 weighs in just over 1000kg, the battery version adds around 100kg and the range extender a further 100kg or so, pushing the total weight out to 1300kg.

Like the BMW i3 range extender, the Mazda 2 EV range extender’s range is dictated by its fuel-tank capacity, which coincidentally matches the new BMW exactly at 9 litres.

Mazda draws a further parallel with the high-tech BMW, saying that early studies indicate CO2 output might get close to the carbonfibre i3. BMW quotes 13g/km; Mazda says its range extender might hit 15g/km, although it stresses that the number hasn’t yet been measured.

What is it like?

This was a very short drive in an early engineering prototype, so it is more appropriate to report impressions rather than draw firm conclusions, but overall the feeling is of a fascinating new powertrain with considerable promise.

Like all electric cars, the Mazda delivers smooth, quiet and instant performance from rest. Acceleration builds gently, thanks to the relatively modest power outputs for the battery and range extender, but felt a little adrift of the 10.8 secs to 62mph from rest that Mazda quotes.

Responsiveness was good, as was the refinement on/off the accelerator pedal, which says volumes for the sophistication of Mazda’s calibration of the motor and its controller at this early stage.

There’s also an EV equivalent of a ‘sport’ button, which adds extra braking effort when the motor is in regeneration mode, but pleasingly Mazda hasn’t overdone the stopping effect, so braking is smoother than some EVs whose strong regeneration effect is felt as an unwanted, nose-diving stop.

In this prototype, there hasn’t been the time to work on details of NVH, so the range-extender rotary engine can be heard thrumming away at constant speed under the boot floor, reminiscent of a fridge/freezer compressor. The noise is intrusive in the rear cabin, less so in the front.

Mazda says it is looking at how to tune the noise of the rotary engine and has to decide whether to silence it or create an attractive note. Another task for the long-term development program.

You also feel the extra weight in the back, when cornering and over bumps, where behaviour is similar to a fully loaded hatchback putting its suspension through the wringer.

Mazda has fitted uprated rear springs to cope with the extra weight of the range-extender battery pack, but it may need to rethink the chassis and steering to balance out the unusual weight distribution.

Should I buy one?

This option won’t be available any time soon, if ever. But if elegant engineering and innovative problem solving are any recommendation, yes would be the answer. And given the extremely low CO2 figure mooted, there ought to be a strong future for this fascinating concept.

Mazda 2 EV Range Extender

Price TBA; 0-62mph
 10.8 sec; Top speed 80mph; Economy TBA; CO2 15g/km (estimate); Kerbweight 1300kg; Engine Rotary, 330cc. (500cc equivalent); Power Electric motor 100bhp; Rotary range-extender 26bhp @ 2000rpm Torque Electric motor 110lb ft; Gearbox Not fitted

Join the debate

Comments
6

Food for thought

44 weeks 5 days ago
I like vegetarian dishes; they can usually be improved with a little bacon or ham. I also like electric cars and they too can usually be improved, with a little internal combustion.

Is a plug-in-hybrid, call it what it is ...

44 weeks 5 days ago
Range-extender/ELR is GM's naming-ploy for marketing and regulation advantages EV+ice=pih/phev no matter how you package it I had a BMW sales rep try to tell me their i8 is not a pih because the genset does not drive the wheels, and he was not open to knowing the wheels are still turned by the genset via the battery its charging (he was blindly towing the company line without having any real knowledge). If the engine (ice) and the EV components drive the wheels, its a parallel plug-in-hybrid If the ice charges the batteries that drives the wheels, its a serial plug-in-hybrid Or you have a design configuration like the GM Volt which can be either or both, but mainly runs as a serial plug-in-hybrid But with the ice-genset kicking @6mph its operating more like a hev hybrid than a pih. It would have been good to know the kWh size of the on-board battery pack and the kW capability of the on-board charger (allows charging of the pack from a wall socket). Also, what type of coupler they would be using (j1772, mennekes, etc.) With a small ice-genset, that reduces its weight and size, and with it running continuously the same energy can be transferred to the wheels via the pack. This design is close to one shown years ago by a UC Davis, CA professor as a charge-depleted configuration phev.ucdavis.edu {brucedp.150m.com}

Mazda has invested heavily

44 weeks 5 days ago
in what it chooses to call SkyActive technology. But this little ripper shows that SkyActive is only a stop-gap - in time to be followed by EVs and PIHVs. I like Mazda. It's sort of where East meets the west. Toyota, Honda are reliability heroes but rarely impress as much in styling and driving dynamics. Mazda seems to me the best of both worlds. Reliable, stylish and fun to drive. A rather creditable fusion of the best qualities of the West and the East.

I've always wondered why

44 weeks 5 days ago
I've always wondered why range extenders needed a normal size engine fitted to charge the batteries. This with it's 500cc tells me it can be done so I wonder if others will follow suit.

Very similar to an earlier Audi A1 e-tron prototype

44 weeks 4 days ago
Note: http://www.autocar.co.uk/car-review/audi/a1/first-drives/audi-a1-e-tron "Audi A1 e-tron Price: n/a; Top speed: 80 mph; 0-62mph: 10.2sec; Economy: 148mpg; CO2: 45 g/km; Engine: Transverse electric motor, rear-mounted Wankel generator; Power: 101bhp at 5000rpm; Torque: 177lb ft continuous; Gearbox: direct drive" Not that the use of a wankel engine is strange for Mazda. If I remember correctly NSU was absorbed by WAG many years ago. So in a sense Audi has that legacy as well, though somewhat less recent.

Range-extender EVs are never

44 weeks 4 days ago
Range-extender EVs are never going to make any sense as long as manufacturers insist on hobbling the range extension with the tiny fuel tank required to meet Californian rules. GM did it properly with the Volt/Ampera so, we know they can fit a larger fuel tank for Europe, if only they make the effort.

 

I'm a disillusioned former Citroëniste.

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