Mazda's Rotary Ready for a Comeback? Looks Like It

By Jacob Brown | March 01, 2012
If you haven't heard of a rotary engine from Mazda, chances are you don't know what it is. That's all right, as Mazda has been struggling with making its rotary engines relevant in the 21st century for a while now. Its last rotary-engine model, the RX-8 sports car, fell under the ax last model year. But Mazda believes it has an answer for making the engine cleaner and more efficient than ever now. Disclaimer: Below are boring technical details to help explain how a rotary engine works. Where normal engines have a set of cylinders that push up and down against one another on a shared crank, rotaries don't. They have a trochoid housing where a small triangular-shaped rotary pivots on a central point, compressing gasses that push it around in a circle. The benefit to such an engine is its compact size and light weight relative to its power output.
But because the inside of the trochoid housing must remain flush for the rotary to rotate, spark plugs, which cause the explosions that move the rotary must be pushed farther back. That means that there's a need for a bigger explosion, which uses more gas and creates a greater amount of emissions. End technical nonesuchery. Thank you for your patience. Mazda's engineers believe they can make the rotary engine cleaner and more in-line with traditional piston engine by redesigning its trochoid housing to better manage airflow. Along the way, it plans to better seal the engine because, at low speeds, rotaries have a tendency to leak gas from one chamber into another, causing an uneven burn and greater emissions. “I can’t specify how we plan to address this problem,” Mazda engineer Mitsuo Hitomi said in an interview with Wards Auto. “But the rotary’s spark plug is in a recessed position, compared to that of a piston engine. “This causes ignitability problems and increases fuel consumption. We’ve found a way to make dramatic improvements,” he said. Rumors have persisted that Mazda is experimenting with lasers instead of traditional sparkplugs to create internal combustion, but no announcements have been made yet to that effect. In the end, the engine will likely be used as a lightweight generator for a plug-in hybrid system, replacing the piston engine used in cars like the Chevrolet Volt and Fisker Karma. But a sports car along the lines of the RX-7 and RX-8 isn't out of the question.'s take: We can see the value behind creating a unique product, but not necessarily when it's selling to a niche audience, especially when Mazda is trying to find a partner to help stave off financial difficulty. It looks like Mazda is putting a lot of development dollars into the rotary engine for pride's sake alone—not to keep its core business afloat. Source: Wards Auto