TOKYO — For the first time in the 50 years since Felix Wankel designed the rotary engine, the fundamental shape of the engine will be changed.
In developing its 16X rotary engine, Mazda Motor Corp. will enlarge both the elliptical shape of the combustion chamber and the rotor's eccentric center stroke. Mazda also will incorporate direct-injection fuel delivery in a rotary engine for the first time, said Seita Kanai, Mazda's senior managing executive officer for r&d.
Mazda's current rotary is 1.3 liters in displacement. The 16X concept engine is 1.6 liters. Mazda expects the new engine to be installed in its cars early next decade.
Kanai predicts the new engine could be the powerplant of hydrogen-fueled cars, because it will ignite hydrogen more efficiently than a piston engine.
The combustion chamber ellipse will be elongated so that the engine has a longer stroke. But from a side view, the depth of each rotary chamber has been narrowed.
Mazda thinks the changes can increase both the horsepower and torque while improving the fuel economy of the notoriously thirsty engine.
But changing the shape of the engine significantly affects the combustion of the air-fuel mixture. That is why Mazda is forecasting several years of development before the engine will be ready for production, Kanai said.
Mazda engineers also are wrestling with where to locate the direct-injection port.
Said Kanai: "We need to find the optimal way to inject the air-fuel mixture, in what position, when it fires and at what angle."