We drive a Mazda prototype that uses an unconventional rotary engine in an unconventional way.
Mazda fans are still waiting for news of a new-generation RX sports car but the company’s signature rotary engine has been put to new use in an electric Mazda 2.
The range extender is a further development of the Mazda 2 EV battery electric prototype CarAdvice drove in 2011 and was made available to lease in Japan (where the 2 is known as the Demio) in 2012.
Range extenders are becoming the new trend in EVs – designed to overcome ‘range anxiety’ that has been one of the biggest reasons, along with costs, for consumer reluctance to embrace electric cars.
General Motors first emerged with the simple yet ingenious set-up with its Volt – where a conventional petrol engine is used solely to recharge the vehicle’s battery pack.
BMW’s forthcoming i3 electric car, which CarAdvice tested recently, is also available with a range extender option.
BMW was different by opting for a motorcycle engine and Mazda has also gone its own route with the rotary engine that has been part of its DNA since 1967.
Mazda has also been clever by positioning the piston-less engine horizontally to help packaging and also reduce vibrations.
It sits under the boot floor, in a compact assembly also comprising the nine-litre fuel tank and generator. It means there’s no major loss of boot space compared with a regular Mazda 2.
The single rotor has a capacity of 330cc with a power output of 22kW at 4500rpm and a potential 28kW at an engine speed of 6000rpm.
The Mazda 2 EV can run on electric power alone until lithium-ion battery power – with the T-shaped battery pack sitting under the floor – starts to become depleted and the rotary engine kicks in, where it’s designed to run at a constant 2000rpm.
On our super-brief drive of Mazda’s first prototype of the rotary range extender, the rotary could be heard to kick at about 10km/h and was more noticeable when we rode in the back seat than when driving.
While not especially loud, we’d like to think Mazda’s engineers might be able to create a more pleasing sound to the generator-like hum.
There’s plenty of refinement in the way the Mazda 2 EV drives, though.
Throttle response is instantaneous, and the 2 rotary extender accelerates with smooth purpose if not exciting pace. There’s not the same surge of acceleration you get in the BMW i3, for example.
The regular EV already weighs about 150kg more than the Mazda 2 you can buy in showrooms, and the range extender adds another 100 kilos.
There’s smoothness to the way the Mazda 2 EV decelerates, with none of the head-throwing antics that have been a common effect with the regenerative braking of some electric cars when stepping off the gas pedal.
For keen drivers who might want a greater engine braking effect, there’s a B mode that can be selected on the transmission. The 2 scrubs speed more quickly in this mode, though is still pleasantly undramatic.
You’re still far more likely to use the brake pedal of this Mazda EV than the BMW i3 that can impressively be driven almost an entire day using the accelerator pedal only so refined is the throttle on/off.
The Mazda 2 can make it to 200km on electric power alone, the company says, with the range extender then capable of doubling that range. Mazda says if the fuel tank was about double the size at 20 litres, that range could theoretically be stretched to 600km.
Mazda believes there’s also “great potential” to create a secondary role for the rotary range extender as a portable power generator for use in emergency shelters, homes, shops or on camping trips, for example.
You’re not going to be able to buy a Mazda electric range extender model any time soon unfortunately, though the Japanese brand believes its rotary approach has “huge potential” for the future.
Our quick impressions of the Mazda 2 prototype suggests it’s an interesting technological solution worth pursuing. Of course there will be many an enthusiast hoping the company still brings out a new car where the rotary engine actually powers the wheels.