Mazda's Rotary EREV

Justin Berkowitz
by Justin Berkowitz
mazdas rotary erev
Recent trash-talking about all-electric range by GM’s Bob Lutz highlights a crucial benefit of the Volt’s Extended Range Electric Vehicle (EREV- nee “serial hybrid”) concept. Though an EREV may be less cost-effective than a plug-in parallel hybrid over the long haul (or not), its initial EV-only range is better. Which means EREV marketers can claim “zero fuel use” for many standard commutes. Autocar reports that Mazda has fallen under the EREV spell; they’re hard at work on their own system using a rotary engine as a battery generator. According to “senior sources,” testing is “sufficiently advanced that Mazda has a working prototype in a Mazda 5 MPV bodyshell.” Unlike GM though, Mazda isn’t relying on its EREV to fly it to the moon by late 2010. Start-stop is the first step on Mazda’s voyage of eco-discovery, set to deploy in Japan next year and around the world thereafter. There are currently no plans to bring an EREV to market. Still, using a small rotary engine as an electricity generator has lots of potential upside. It eliminates the engine’s thirstiness by running constantly at lower rpms, and could actually be more efficient at battery-charging than a standard ICE. Hopefully the system won’t be entirely dependent on rotary engines though, as Mazda’s sister company Ford will doubtless be interested in appropriating the technology.
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4 of 12 comments
  • Shaker Shaker on Sep 05, 2008

    psarhjinian : Let's see - Gas turbine: Continuous combustion with no vibration, the ability to run on a variety of fuel sources, no worrisome seals (and lubrication-related emissions), compact size/power ratio, efficient when run in a relatively narrow RPM/load range (which a generator would supply). Rotary: All the problems mentioned above. I would still work with the turbine myself.

  • Monkeyboy Monkeyboy on Sep 05, 2008

    The rotary is a perfect hydrogen engine. Yes it does run well on hydrogen. So it doesn't surprise me. It also runs on many other fuels and can run a long time at steady state, with few emission related issues. It starts to lose efficiency with varying loads. Imagine on on 85% ethanol. Many here have no experience with Rotaries to be speaking. Oh wait. It's the INTERNET...

  • Shaker Shaker on Sep 05, 2008

    "Oh wait. It’s the INTERNET…" Bill Kurtis? ;-)

  • Orenwolf Orenwolf on Sep 05, 2008

    Blunozer: the RX8's RENESIS engine fixed the issues of the RX7's DEI and REW Variants - the focus of that development was better fuel economy and exhaust emissions. Apex seals are also no longer an issue. The "RENESIS2" that Debuted with Mazda's Taiki car moves even further in this direction but adds direct injection, further increasing fuel economy.