The rotary engine, this unsung hero of the automobile, is making a grand return to the forefront thanks to an unexpected player: the Chinese group Changan. Long considered a dinosaur due to its reliability and consumption issues, this type of engine could well experience a second youth. Hold on tight, as the Wankel might just make headlines again, but this time with a Chinese twist.
A complex and controversial legacy
The rotary engine, often referred to as the “Wankel” after its inventor, has always evoked as much admiration as it has suspicion. Despite the tireless efforts of Mazda, which has managed to leverage the advantages of this technology, such as its compactness and lightweight, it has never succeeded in dominating the market. The reputation of this engine is marred by a lifespan that is often limited and excessive oil and fuel consumption, two critical flaws at a time when oil prices began to soar in the 1970s.
To this day, only Mazda persists in using this solution, notably as a range extender in its MX-30 SUV. Unfortunately, the result has not lived up to expectations. At a time when the electrification of models is at its peak, the resilience of the Wankel seems more than ever put to the test. But here comes Changan, with its subsidiary Harbin Dongan Auto Engine, throwing a lifeline to this old concept.
Harbin Dongan Auto Engine, a subsidiary of the Chinese group Changan, has developed a new rotary engine. © Dongan
A Chinese innovation: the R05E
Harbin Dongan Auto Engine recently announced that it has successfully started the very first Chinese rotary engine, named R05E. This single-rotor engine adopts the principles of triangular pistons with curved edges, but with a modest power output of 57 kW, or about 72 hp. It is not with this power that supercars like the legendary Mazda RX-7 or RX-8 will be created, but the true ambition of this engine seems to lie elsewhere.
Indeed, the R05E is intended to be integrated into flying vehicles designed for low-altitude transport. A sort of cross between the automobile, drone, and aviation. In this futuristic perspective, the Wankel could prove particularly suitable due to its compactness and high specific power, while offering optimised management of noise, vibrations, and harshness (NVH). Who would have thought that this engine, in need of recognition, could one day take flight?
The Mazda MX-30 SUV is the latest car equipped with a rotary engine, here used as a range extender. © Mazda
A bold ambition for an unloved engine
Changan does not stop there. To counter the insatiable appetite for fuel traditionally associated with rotary engines, the brand has designed an innovative aluminium block, coated with an NDC (nano-diamond composite) anti-friction coating. This technology could well be a game changer and allow the R05E to be less thirsty than its Japanese predecessors. However, the question remains: will this engine truly be able to compete in terms of reliability and longevity?
So far, the Wankel has often required a rebuild before reaching 100,000 km, which has discouraged many potential buyers. This new project could indicate that China is not only catching up technologically but is also exploring paths abandoned by others. This is also evidenced by the arrival of a flat engine at Yangwang, a premium subsidiary of BYD.
Like the start-up Xpeng, China aims to develop vehicles that are a cross between drones, planes, and cars capable of flying at low altitudes. © Xpeng
Towards a new era for the Wankel?
This return of the rotary engine could well mark the beginning of a new era. The technological advancements implemented by Changan testify to a paradigm shift in the Chinese automotive industry. Instead of merely copying Western giants, Chinese manufacturers are beginning to innovate by relying on forgotten technologies. A bold strategy that could breathe new life into the Wankel and offer interesting alternatives in a world seeking sustainable solutions.
It remains to be seen whether this renaissance will be enough to convince consumers and regulators. The transition from an innovative concept to a reliable and high-performing product is always fraught with pitfalls. But if anyone can achieve this, it is Changan, which seems determined to turn this dream into reality.
This Yangwang U7 sedan, offered by a premium subsidiary of the Chinese giant BYD, receives an original flat engine as a range extender. © Yangwang
