Mazda Patents Stop-Start, Range-Extender Tech for Rotary Engines

Mazda Motor Corp. has received two U.S. patents for stop-start and range-extender systems for its rotary engine.

One patent is for a range-extender technology that could be used with a conventional or rotary engine. The system is similar to the technology the carmaker used in its 2015 Mazda2 RE Range-Extender concept vehicle, which featured a tiny 330cc rotary engine that powered an electric generator on the rear axles while an electric motor drove the front wheels.

The second patent is for a rotary engine-based stop-start system. The technology works the same as a stop-start system for a piston engine, turning the engine off when idling at a stop light and immediately starting it back up when the brake pedal is released.

The Mazda stop-start system positions the rotor so that it closes the intake port to prevent fuel or exhaust emissions from seeping out through the intake tract. Rotary engines are susceptible to such leaks through ports that are opened and closed by the rotor.

The stop-start patent also includes provisions for firing a sparkplug to eliminate any residual emissions after fuel has been cut to the engine. Mazda says the system could significantly improve fuel economy and emissions, which have been problematic for previous rotary engines.