You can’t buy a new car powered by a Wankel rotary engine today, but engineers around the world are looking for a new spin on the dormant technology.
The latest is from an outfit in the U.K. called Advanced Innovative Engineering (AIE), which has demonstrated what it bills as the first ever single rotary-powered British car to lap a racing circuit.
The appeal of the Wankel is largely due to its compact size and smooth-running character, but it is notoriously difficult to cool, relatively fuel inefficient and burns a lot of oil that’s used to lubricate the rotor seals, leading to poor emissions performance. These are some of the reasons Mazda discontinued its last Wankel-powered car, the RX-8, in 2012, although it continues efforts to resurrect it.
What AIE has developed is a technology called a Self-Pressurizing-Air Rotor Cooling System, or SPARCS, that it claims better controls engine temperatures and reduce oil consumption.
As AIE explains it, SPARCS taps into the blow-by gasses that escape from the rotor’s side seals into the engine core and uses a shaft-driven fan to circulate them through a heat exchanger and back past the rotor to cool it. It says that the high density mixture does a better job transferring heat than atmospheric air can, while improving the thermal stability of the engine, quickly bringing it up to and maintaining operating temperature, reducing wear and tear on its parts. The closed circuit system also reduces the amount of oil that makes its way into the combustion chamber, reducing oil consumption and emissions.
Several versions of the engine have been developed, but AIE installed a 120 hp 650cc example into a lightweight Westfield roadster, which was inspired by the Lotus 7. AIE says the core of the engine weighs 62 pounds, and that it is half the weight and size of a similarly-powered 4-cylinder engine, but has yet to detail exactly how efficient it is, citing plans for further test runs. (If nothing else, it sounds great.)
Along with automotive applications, AIE is pitching the technology as suitable for hybrid powertrains, portable generators, marine and aviation use, and has also built a 5 hp unit that weighs just 4.4 pounds.