Mazda has long been a persistent believer in the potential of the rotary engine. The rotary (also known as the Wankel engine) has been around for awhile, but following a brief period in the 1970s where the novel engine was viewed as a potential solution to improving fuel economy, the engine has largely languished in the background. The last production model to utilize one was (unsurprisingly) the long axed Mazda RX-8 sports car. But Mazda has not given up on the idea of using it, and a recently unearthed patent appears to suggest that Mazda is closer to reviving the engine for renewed production than first realized.
The patent in question was published in Japan, and appears to show a powertrain equipped with a front mounted combustion type engine that is turning the rear wheels with the help of an electric motor. The front end would have an electric motor in each wheel, with the duo getting power from an internal capacitor system. The end result is an electric all-wheel drive vehicle that could have advantages in terms of weight savings especially when compared to current vehicles of its type.
The technology would be powered by a small 3.5 kilowatt lithium ion battery pack that would operate at 48 volts. Part of the reason why the small capacity works here is because of the way the capacitor is packaged, with the unit being mounted under the hood with the combustion engine. The proposed system recharges using regenerative braking, and when the voltage level between the terminals of the capacitor reaches a certain point, that charge is funneled directly to the battery. This ingenious setup makes the most sense when the driver needs more power for acceleration, with the battery being able to supply the power needed if the capacitor does not have enough energy to do the job. In addition to its position, the capacitor is also lighter than a traditional battery while reduced wiring helps slim weight down even further.
The patent also reveals that for the bulk of driving, the combustion engine and the electric motor drive the rear wheels, however if a sudden burst of acceleration is needed, or if the driver chooses to do more spirited driving, the in-wheel motors can help enhance power. It’s worth mentioning that the patent itself states that the system can be equipped to V, inline, or rotary type engines, but a small section does state that the rotary engine is the one that can deliver maximum results while being the most compatible with the compact requirements needed for the system to work. This goes along with prior rumors and speculation that we have seen prior to this, with evidence mounting that Mazda is working to bring back the rotary engine in one way or another.
If the rotary engine does not return in the system that is described in this particular patent, the world might still have a chance of seeing the engine come back. Mazda is investigating the possible use of such an engine in its upcoming MX-30 electric CUV, but unlike prior uses, the rotary here would actually be used as a range extender to help improve the MX-30’s driving range. The next few years will be a key period for the purported development of both the system mentioned here, as well as the other various projects that Mazda has for the rotary. Details are still scare, but look for more information to emerge possibly in the next few years.
Carl Malek has been an automotive journalist for over 10 years. First starting out as a freelance photographer before making the transition to writing during college, his work has appeared on numerous automotive forums as well as websites such as Autoshopper.com.
Carl is also a big fan of British vehicles with the bulk of his devotion going to the Morgan Motor Company as well as offerings from Lotus, MG, and Caterham. When he is not writing about automobiles, Carl enjoys spending time with his family and friends in the Metro Detroit area, as well as spending time with his adorable pets.