Rotary could resurrect RX-7
A ROTARY engine that uses half the fuel of its predecessor could be the key to the return of a Mazda RX-7 sports car.
The petrol-powered rotary is promised within three years as Mazda — the only company to make a long-term commitment to the rotary design — works on three projects for the powerplant.
Apart from the overhaul of the engine now used in the RX-8, Mazda is developing a rotary that runs on hydrogen and another that powers an onboard generator to drive the car — in a similar way to the Chevrolet Volt — through electric motors.
The petrol rotary is for a two-seater coupe expected in three or four years. Though Mazda isn’t saying anything about the car, it’s an open secret that it is working on a revival of the RX-7 which was its sports car headliner for more than 20 years. Mazda’s senior program director of research and development, Seita Kanai, says Mazda is not going to abandon the rotary.
Powertrain Development Division head Mitsuo Hitomi says the same principles that make the Sky-G engine series more fuel-efficient and torquier are being applied to the rotary.
‘‘This includes making the engine a long-stroke,’’ he says.
‘‘You can do that with a rotary — but of course it’s a different technique to an ICE (internal combustion engine). The spark plug area . . . can be changed considerably.
‘‘The rotors can also be made slimmer, which is part of changing the compression ratio.
‘‘Then you can also remove a lot of weight in and around the engine.’’
Rotary platform? Mazda recently revealed its sleek Shinari concept.