The Wankel Rotary Engine, of unique design and origins, is the only mass-produced engine to have been conceived in the 20th century, while piston-crankshaft engines can trace their roots back at least 150 years. What makes the rotary engine so desirable is in its simplicity.
The rotary engine contains far fewer moving parts than a traditional piston engine, the result being less weight and more durability. Power output is smooth, especially at the higher rpm ranges which top out near 15,000rpm, unlike their piston counterparts’ 8,000rpm redline.
Mazda is one of the few automakers to put the rotary engine into mass production, but there is one weakness in the lineup of RX-7 and RX-8 rotary-engine Mazda, fuel consumption and emissions. This was especially critical as fuel prices were starting to rise in the mid-1970s and continue this day.
The RX models continued to be popular anyways because of their sporty handling and performance. Now, with the implementation of new emissions regulations, both here in the US and in the EU, the rotary engine cannot meet the stricter standards.
At first, instead of putting money into research and development of a cleaner rotary engine, Mazda simply dropped the RX line which became so popular, simply because of the motor architecture. The RX’s popularity, though, seems to have piqued Mazda’s interest in redeveloping the rotary engine for the stricter emissions standards.
Results from the SkyActiv engine-efficiency project and advanced ignition systems could help the rotary’s development, but nothing is confirmed at this time. Engineers would love to see a new emissions-compatible rotary engine in the next five years, which is good news for lovers of the RX, including Takashi Yamanouchi, CEO of Mazda, who said, “The challenger spirit that has made us the world leader in rotary engines is still alive and well at Mazda.”