Range Extenders?

Discussion in 'General' started by Geoff Shelley2, Oct 6, 2018.

What are your thoughts about this range extender www.aquariusengines.com

Poll closed Oct 13, 2018.
  1. Great idea

  2. Stupid idea

    0 vote(s)
  1. Geoff Shelley2

    Geoff Shelley2 New Member

    Hello All,

    I want to know what people think about EV range extenders. What are your thoughts about range extenders, both generally and more specifically about this one www.aquariusengines.com?
  2. bwilson4web

    bwilson4web Well-Known Member Subscriber

    The web page could do with more structured approach because I can't see which one describes the engine architecture. So I used Mr. Google and found:


    PSA Groupe is evaluating a free-piston engine linear-generator under development by Israel-based start-up Aquarius Engines for use as a range-extender in its electric vehicles. Accordingto a report from Reuters, PSA Research and Development Director Gilles Le Borgne said that while the company is evaluating the technology, “Nothing has been decided yet.” According to Aquarius, several prototype vehicles using its free-piston generator will be road-tested by 2017.

    A number of groups have recently or are currently investigating the use of free piston engine power generation applications with a focus on automotive, including academic work at West Virginia University (WVU), Sandia National Laboratory (SNL), Chalmers University of Technology (Sweden), and Shanghai Jiaotong University. (Earlier post.)
    . . . ​

    Another approach: https://en.wikipedia.org/wiki/Achates_Power

    Achates Power is an American developer of opposed-piston, two-stroke, compression ignition engines for use in commercial and passenger vehicles. Based in San Diego, California, the company was founded in 2004 by James Lemke.

    According to Achates Power, its opposed-piston, two-stroke engine has demonstrated an increase in fuel efficiency and similar engine-out emissions levels[1][2] when compared to the Ford Power Stroke engine, named one of the leading medium-duty diesel engines.[3] More recently, the company published a technical paper citing a 30 percent fuel economy improvement when its engine was benchmarked against a next-generation diesel engine equipped with advanced technologies.[4] The paper also highlighted the Achates Power engine's potential to meet Tier 3/LEV III emissions and 2025 CAFE.

    Achates reports high thermal dynamic efficiency and I find it credible because there is no valve train. The free piston engine should also have similar efficiency for the same reason. I notice that a Wankel engine is being tested for range extender which means it can be tuned for high efficiency and low emissions.

    I drive a 2014 BMW i3-REx with a 34 hp (25 kW) range extender that uses a repurposed, 640 cc, motorcycle engine. Higher efficiency would move my highway MPG from 40 -> 45 MPG. I have plans for cooled, exhaust induction that should reduce throttle losses and boost MPG.

    As for Aquarius and Achates, they have patents and are trying to sell the idea to existing car makers. IMHO, this is unlikely to work. A better approach would be to find a 'glider' source and build out their own plug-in system. The other alternative, make a retro-kit for existing EVs:
    • Leaf - there are a lot of them
    • Bolt - more modern (and GM engineering needs shaming)
    Offer an after market, range extender solution; go through the EPA/CARB emissions testing ($500,000), and; sell the conversion kits.

    Bob Wilson
  3. Geoff Shelley2

    Geoff Shelley2 New Member

    Bob thanks for your response and post.
    I've read that the unfortunate thing about the i3 is that BMW is trying to qualify for emissions/economy credits with the car and so it is greatly limited in the amount of electricity produced. I'd also heard that about the wankel as an extender, but this design seems more promising for electricity generation, simpler design. I have to laugh at aquariusengine's info on their website. They say they've reinvented the engine, when in fact the idea isn't entirely new and isn't really theirs. The work seems to be based on other research such as .

    But regardless, I hope someone can persuade an EV mfg to use of one because it would enable the mfg of a much less expensive EV (perhaps $26,000) today with current tech, no waiting for next gen batteries or anything. I also argue why haul around hundreds of pounds of battery range every day, everywhere, when most of us only need that range once in a while. Makes a lot more sense to me to have a smaller battery pack that will get me around most of the time and then an inexpensive range extender for that occasional longer trip.
  4. bwilson4web

    bwilson4web Well-Known Member Subscriber

    Perhaps an aux generator trailer?

    Transportable 50 kW charger?

    Bob Wilson

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