By on March 19, 2013

The gasoline range-extender that will be optional in BMW’s i3 electric car will be built by Kymco, a Taiwanese firm that is best known for its scooters.

BMW and Kymco have worked together in the past, with Kymco building engines for the BMW G450X dirt bike. The two-cylinder motor was designed in Germany but built by Kymco’s Taiwan factory – and the i3 will likely have a similar arrangement, given the familiarity between the firms. The parallel-twin will apparently be given extensively changes for the i3, especially given that the requirements for a motorcycle engine and a range extender being run at a constant load are very different.

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26 Comments on “BMW Partnering With Kymco For i3 Range Extender...”

  • avatar

    It seems like a better option for a range extender would be a gas turbine engine, which has a near double thermal efficiency output of an ICE. Even diesel would be a better choice. Trains and a lot of ships are going to Diesel generators with electric drive.

    • 0 avatar

      Railroad locomotives have been predominately diesel-electric for as long as they have been not powered by steam. BUT, that is primarily for reliability reasons, not efficiency. The Europeans long ago proved that a diesel-hydraulic or diesel-mechanical transmission is more efficient, but they require a lot more maintenance and/or are less reliable. Note that most diesel electric locomotives have no energy storage capability – there are a very few that have battery banks and can run off them for short distances for specialty purposes.

      I very much agree that a tiny gas-turbine would seem like the ideal range extender. Incredible power-to-weight ratios, and using it as a range extender charging batteries gets around the fact that turbines are only efficient at essentially full power. Good NVH characteristics too compared to a reciprocating engine.

      • 0 avatar
        Dr. Kenneth Noisewater

        Yep, they radiate braking heat out into the air rather than regenerate, probably because of the cost and weight of batteries. I do think a diesel-electric truck would be a win though, especially if you could add motors to the trailer and cable it up to the tractor so you’d get extra traction and braking. Trucks spend a lot of time idling to keep the engine warm and to provide cabin temp and electrics while parked, and being able to plug in in those situations would reduce fuel use and engine hours quite a bit.

        • 0 avatar

          Plug in … to what?

          Rest areas and truck-stop parking lots don’t have power they can just tap in to.

          (Now, for certain uses in – epecially – the mountain West, the idea of a trailer with an electric motor has merit!

          But it’s a big logistic hassle to make sure those trailers go there, and not else where … and that other trailers don’t go there, where they’ll make it pointless.)

          • 0 avatar

            Plug in… to “shore power”.
            Most rest areas have some sort of power.
            Electricity costs much less than idling a diesel truck. A big 10L or 15L engine can use a gallon per hour. That’s like paying $5/hr for the a/c in your hotel room. Truck engines were not made to be generators for such small loads.
            So, a few companies, filling station chains, etc, have run electricity to each truck parking space, and sell electricity to the truckers. However, unless you have a specially adapted electric ac compressor & fan, it doesn’t help with heating/cooling. So, there are services that combine telephone, cable, internet, air conditioning, power, etc., into a window box, just roll down the window and stick this thing in.

    • 0 avatar

      Trains have been using the engine as a generator primarily because its a lot easier to use electric motors & cables as the “transmission” to power all the locomotive’s wheels (since the low-friction surface of steel wheels on steel rails requires many wheels to be driven) with the amount of torque required. It also allows them to use the electric motors as brakes, dumping the generated current into giant resistor banks (no storage, unlike a hybrid), so that the brakes aren’t primarily relying on a friction & wear item such as brake pads/shoes.

      Modern diesel engines are much more expensive, require more aftertreatment than gas engines (at least if they’re going to be more efficient), are heavier and take up more space than gas engines, which are all big downsides to fitting a “back-up” style range extender into a smaller vehicle that already has a lot of space taken up by relatively heavy batteries, which also happen to be quite expensive. You’d either need to sell this combo for MUCH more $$, or decontent somewhere else – neither of these strategies promise very much public acceptance.

      Turbines are interesting, but also pricey, would likely require aftertreatment too (NOx problems). Worst for turbines is that to be reasonably efficient (like they are for power generation), they require LOTS of cooling capacity for bottoming cycles etc, which adds a lot of space for radiators, air passages, weight, packaging complexity & drag, all of which you can’t tolerate in a small vehicle.

    • 0 avatar
      Felix Hoenikker


      While I like the idea of a gas turbine as a range extender, the efficeincy of gas turbines falls of quickly with decreasing size. IIRC, the power required for a range extender is too small for a turbine to furnish efficiently.

    • 0 avatar
      Brian P

      Gas turbines can only have a decently high thermal efficiency in large (utility power generation) sizes due to unavoidable Reynolds number effects that show up when you try to scale them down. Also, they can only be efficient if they use multiple stages of compression with intercooling between the stages (expensive, bulky, heavy heat exchangers), followed by a regeneration stage (exhaust heat transferred into the compressed but low-temperature post-compression air), and that is another expensive, bulky, heavy heat exchanger. All of this is only practical for stationary, utility power generation applications.

      The old Chrysler gas turbine engine used regeneration but not multi-stage compression and intercooling, and even with that, it had very poor thermal efficiency. There is no magic involved here. At an automotive scale, a gas turbine is not a good choice, and will have poorer efficiency than a gasoline engine, nevermind a diesel engine.

      A spark-ignition engine for this type of application can have a number of efficiency-boosters that will get it close to that of a diesel, with fewer emission-control headaches. Atkinson cycle, etc. A gas turbine on the same scale cannot come close.

      By the way, a gas turbine IS an internal-combustion engine. It just uses the Brayton cycle, rather than the Otto or Diesel cycle.

  • avatar

    Kymco also builds the current BMW maxi-scooter twin motors. For a short while, I think they also made the F650GS single motor too. I heard Kymco had a non-compete agreement with BMW, hence the lack of motorcycles in recent years from Kymco.

    • 0 avatar

      Kymco has a pretty good reputation for building scooters. I wouldnt call them “top tier” like Honda, Yamaha, and Suzuki, but they arent Chinese junk.

      That said, its a $12k scooter. No thanks. $8k out the door for my TMax would have seemed bad if i hadnt been waiting almost 10 years for Yamaha to finally bring it to the States. 2 years, 22,000 miles later, no regrets.

      • 0 avatar

        And now the TMax is gone again. Oh Yamaha, you’re such a tease!

        I bought one too. :-))

      • 0 avatar

        Yes, but have you actually rode one of the new BMW maxis? I own a 2012 Suzuki Burgman 650 Exec, which I think is the best maxi-scooter in North America. But damn, one test ride on the BMW C 650 GT and I was silently envious. The price is a killer, though. I paid $9,000 for my (then) new 2012 Burgman. $12,000 is way too much.

        My wife looked at the TMax, but bought a Burgman like mine. The TMax is certainly more sporty.

        • 0 avatar

          I had a Burgman 650 too. It’s a different ride than the TMax, although both feel like they’re riding on rails, during turns.

          Unless your wife is really tall, the TMax would be a bit unwieldy for her. I agree, the Burgman 650 is the ultimate cruising scooter.

          The BMW scooters look more than a little bit influenced by the TMax’s design (being very generous here), but having said that, I’ve not ridden one, and I’m sure they’re great, and kudos to them for selling them in the USA.

          One nice thing about Suzuki and BMW scooters is that they’re offered here intact; whereas, Yamaha stripped-out lots of goodies from the North American version of the TMax. Hate when companies do that!

          Kymco, as mentioned above, has always been the most well-respected Taiwanese brand, and should never be confused with anything coming out of Mainland China.

          • 0 avatar

            I had a Burgman 400 too. That thing scared me to death. It is soooooooooo not a Jr. Burgman 650! Scary back-end on turns!

    • 0 avatar
      Dr. Kenneth Noisewater

      Perhaps it’s size-related, since BMW’s selling megascooters now?

      • 0 avatar

        You might be onto something. Kymco’s taking a while to launch the big MyRoad 700i here in North America.

        But I’m quite happy with my significant other’s Downtown 300i, and I can still get a Venox 250 cruiser new old stock in crate still. T-MAX is still up here in the Great White North! My friend bought a new T-MAX 530 to complement his Multistrada. Gorgeous bike. He looks like he’s having great fun.

  • avatar

    Volvo had a Turbine/electric concept car in the 1990s called the ECC. Introduced with great fanfare in the buff books, it vanished with nary a whimper. It would be nice to find out what Volvo learned from its experience.

  • avatar

    This is a good idea, since it will be a more optimal package than a standard ICE transplant (like the Volt).

  • avatar
    el scotto

    Oh I can see it in the near future. Some preening hipster exclaiming in the Whole Foods parking lot: “It’s a BMW and Electric; it’s just so green and eco-friendly!!! Nevermind the range extender was built in Taiwan and shipped to Germany and then the whole car was shipped from Germany to the US. Yeah, that’s green.

    • 0 avatar

      “Nevermind the range extender was built in Taiwan and shipped to Germany and then the whole car was shipped from Germany to the US.”

      Considering the fuel a car uses over its lifetime, the transit fuel to build it is nothing.

      • 0 avatar
        el scotto

        Not hating on the Leaf :)I’d still like to see environmental studies on the electricity produced to power electric cars and the environmental costs of their production. Too many follow the meme of “Hybrids are good!”; the learned that after “SUVs are bad” wasn’t cool anymore.

        • 0 avatar

          Those studies have been done.

          There are several considerations:
          1. Cost of your local electricity.
          2. Type of fuel that generates your local electricity.
          3. Life cycle ‘green-ness’ of the car.

          I’m not actually a green weenie, but I don’t mind polluting less and saving on fuel costs. And being a geek engineer with an ideal lifestyle for an EV, I’m willing to tolerate its limitations.

          I pretty sure my local electricity – while very cheap ($0.054/kWh) is produced by coal. A study I read (can’t find it now…) indicated that given the Leaf’s consumption, its MPGe made it ‘greener’ by about 17% than the dirtiest coal available. Oil, natural gas, and nuclear generation would be even better.

          In the case of the Leaf, I think Nissan designed most/all of it to be easily recycled so as to reduce its life cycle environmental costs.

          So if your electricity is expensive, the savings take longer. If your electricity is the dirtiest coal available, you may still be ahead.

          • 0 avatar

            EPA has a web page that shows the “energy mix” of electric utilities by Zip Code:


    • 0 avatar

      As gslippy has said… the cost of transport of subcomponents pales in comparison to the lifetime costs associated with running the vehicle.

      And huge economies of scale in terms of shipping means that the costs of shipping, both in terms of fuel used and emissions… emitted… is actually very, very small per unit…

  • avatar

    If one would listen to the “laundry list” of how environmentally “unfriendly” EV’s are, one would think twice about buying one.
    Which is exactly what Big Oil wants.

    There are people (admittedly, well-off) who own EV’s and have solar/wind power at home who can literally drive for free (once the initial investment is out of the way).

    Yes, they’re a very small minority, but it just proves that IF WE REALLY WANTED TO, we could do most of our personal driving with NO OIL.

    It’s feasible.

    • 0 avatar
      Dr. Kenneth Noisewater

      It’d certainly be more feasible with thorium molten-salt reactors supplying safe, cheap and clean nuclear power and high-quality heat by burning up the decades of radioactive waste currently sitting in cooling tanks waiting to leak along with the thorium that currently has a negative economic value.

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