CAR EXPLAINS
Is a rotary range extender the best of both worlds?
It’s been more than a decade since you could buy a new car in the UK with a rotary (or Wankel) engine, but longstand-ing Wankel advocate Mazda has declared the technology a vital part of its electrification strategy. The new MX-30 R-EV features a rotary engine acting as generator, extend-ing the MX-30’s range from around 100 miles of pure elec-tric driving to a claimed 373 miles of hybrid motoring.
This EV-first application sets the MX-30 apart from other series hybrids (that is, a hybrid powertrain where the wheels are only ever driven by the electric motor, and the combustion engine charges the battery). But Mazda is never one to follow convention. Hence its adoption of Wankel power for production cars beginning in 1965 and ending – until now – with the demise of the RX-8 in 2012.
A Wankel is an internal-combustion engine, but instead of pistons sliding up and down in cylinders it involves a rotor moving within a chamber. It’s compact, smooth and light, but also thermodynamically inefficient, and prone to wear of the rotor tips.
Wakako Uefuji, programme manager for the MX-30, explains how Mazda thinks rotary fits into the big electric picture: ‘We wanted to make more solutions for people who are interested in BEV [battery electric vehicles] but their living environments mean they need a higher cruis-ing range.’ While long-range EVs are taking off in Europe, they’re less popular in Asian markets. And while a big-ger-batteried MX-30 would be possible, it’d also be pricey, whereas this R-EV is no more expensive than an EV.
