By on May 21, 2011

“The biggest problem” that faces widespread adoption of electric vehicles, “is striking a balance between performance and price.” The man who said that, Hiroshi Shimizu, thinks he has the solution to this problem. It is not generous subsidies. It is not miracle batteries. It is a technology his company has been developing over many years: In-wheel electric motors. Shimizu’s company , “SIM-Drive Corp. a Keio University-linked venture company, on Wednesday unveiled a prototype of its SIM-LEI electric vehicle that can travel up to 333 kilometers (206 miles) on a single battery charge,” writes Japan’s Jiji Press.

The “LEI” has nothing to do with Hawaiian flower necklaces. It stands for Leading Efficiency In-Wheel motor, says the Kawasaki-based company. Powered by a 24.5 kWh battery, pretty much the same as the Nissan Leaf, the 4-seater achieved “333km of range per charge by JC-08 mode, which represents general urban traffic condition in Japan,” says the company. Unusual is the acceleration: 4.8 seconds for 0 to 100 km/h, not quite a Veyron, but better that a Porsche 993 Carrera RS 3.8.

SIM’s in-wheel engines can be retrofitted to existing cars, an operation that should be as simple as changing tires (it probably won’t be.) For purpose-built cars, the in-wheel motors allow for a simple body structure, a lot of space, and stable running.

I know, by now you are racking your brain: “Hiroshi Shimizu, Hiroshi Shimizu, didn’t I hear that name before?” You did. He’s the man behind the 8-wheeled 370 km/h (230 mph) Eliica that also used SIM-drive electric hub motors. Keio is a Tokyo elite university. Hiroshi Shimizu is a professor at the school.

(Hold your comments of the design of the car. SIM intends to sell the technology, not the body.)

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41 Comments on “206 EV Miles On A Single Charge With A SIMple Solution...”

  • avatar

    Nothing new under the sun. Lohner-Porsche Mixte Hybrid had in-wheel engines and a completely friction free drivetrain in 1899.

    • 0 avatar

      Yes. Jacob Lohner & Co in Vienna, Austria produced electric cars from 1898 to 1906. Ferdinand Porsche, one of Lohner´s employees developed a drive system based on fitting an electric motor to each front wheel without transmissions (hub mounted). Vehicles of this type were known as Lohner-Porsches. Also: Ferdinand Porsche may well have invented 4 wheel drive. And guess what…it was a 4 wheel drive vas a Hybrid Vehicle. BTW, my profile pic has been a picture of the above mentioned Lohner-Porsche.

  • avatar

    I’ve read about the in the wheel motors before made by a British company for Mini’s and the biggest hurdle they had to overcome was brakes. Simply the car didn’t really have them which made it really difficult to make it legal to drive. Also would unsprung weight be a problem? Or since the absence of said brakes would remove what they add back in motor it doesn’t change much?

    Edit: And whats with “awaiting moderation” is that new?

    • 0 avatar

      Seems like Alfa/Jag-style inboard discs would be a good solution to that problem. Unfortunately it would make it a pain in the butt to service the brakes but since the rest of the car is so low-maintenance it wouldn’t be that big of a tradeoff.

      • 0 avatar
        johnny ro

        not hard to service if they stay away from Jag/Alfa design tricks like “Remove rear of car to reach brake discs”. It could be quite simple really.

        The basic idea of electric motor in wheel is elegant.

        My Friends at New Venture Gear used to think this is what would kill that company in the end, coupled with their own acknowledged failure to lead in the market. They were wrong, it was high costs in Syracuse NY, they did not last long enough to be killed by competitors innovations.

      • 0 avatar

        My 72 Citroen DS has inboard breaks which are one of the few easy things to service on that car. Open the hood and they are inside the fenders.

      • 0 avatar

        Only a trade off if you use those brakes. I would assume that all the normal braking is done on the electric motor

  • avatar

    I like this idea, I’ve heard about it before. But this car is so stupid ugly, i can’t even look at it. I am willing to deal with range issues with cars, but not ugly.

  • avatar

    Diesel and petrol is approx 46MJ/kg. Batteries are 0,14MJ/Kg. Good batteries has 0,25MJ/Kg, fantastic batteris even more (036-2,23 for Lithium-ion).
    Electric motors are much more efficient than combustion engines but….. Well, do the maths.

    • 0 avatar

      you forget that the IC only uses about 15-20% (partial load!) of the energy. the e-motor uses over 90%.

      Battery enegry density still looks bad, but not as bad as you think.

      the 4-wheel drive would enable really cool vehicle stability things. now VSC only applies brakes to certain wheel,s not we could apply torque to specific wheels.

      BTW: what is that facebook BS when posting a comment??

      • 0 avatar

        I can clearly see that I wrote “Electric motors are much more efficient than combustion engines but…..” That was about the IC´s lousy efficiency. On the other hand the IC often uses 100% of the energy, at least allmost half of the year here in Sweden (heating). But I agree that this is a silly remark as most people in the world are more concerned about AC than heating.
        I don’t know about the facebook BS, I’m just using FB as a mean of logging in. Is it disturbing you?

      • 0 avatar

        Heating actually is a good point as it concerns much of the US and Canada too (and Europe)

        the Facebook question was towards TTAC. when I posted the comment it wouldn’t let me first without signing into Facebook. WTF????

        And i somehow was signed in a some other unknown TTAC member. Is that a new feature to automatically hack into some others TTAC member account?

      • 0 avatar

        @ HerrKaLeun: Ive written emails to TTAC before because this same thing has happened to me before. I don’t remember getting a response, and since it seems to still be happening, it would appear no one there seems too worried about it. Or I was ignored and no one there cares about the problem lol.

    • 0 avatar

      @Gunnar Nilsson

      You also forgot about that people don’t need a lot of range. A typical compact ICE car would carry 15 gallons of gas for about 400 miles. That’s all they need. 15 gallons of gas is about 90 pounds.

      Let’s say, the battery weights 600 pounds. But it’s really not 90 vs. 600. It’s more like 3090 vs 3600, when you take consideration of the rest of the car. There is a difference, but not big. You point would only be valid if people need to carry 1000 pounds of gas (for 4400 miles).

  • avatar

    “SIM intends to sell the technology, not the body.”

    How disappointing to hear that.

  • avatar

    Some heavy mining trucks use wheel motors, when you consider the weight they are hauling they are very fuel efficient. The wheel motors provide regenerative breaking for speeds above 7mph, and there is a hydraulic service break to bring the truck to a complete stop.

    This ev sounds as though it has adapted some of these ideas on a much smaller scale.

    Mining trucks are not ev or hybrid, they have a diesel engine driving an alterator to power the wheel motors. Hybrid technology would make a lot of sense in this application, but the batteries aren’t there yet.

    • 0 avatar

      “they have a diesel engine driving an alterator to power the wheel motors.”

      That’s the definition of a series hybrid.

      • 0 avatar

        That is what the automakers would lead you to believe is a series hybrid but until you add a battery it doesn’t even meet that definition. To make a true hybrid though you need to add a plug so the power can come form a source other than the ICE.

  • avatar

    The thing will most likely drive like a van with such heavy wheels, but removing any extraneous powertrain parts should have been priority number one with EVs from day one. CV joints and differentials waste loads of energy.

  • avatar

    that’s more like it.

  • avatar

    Isn’t this what Mitsubishi was all excited about 5 years ago and Siemens made a big push for in-wheel motor acceptance too? I doubt those companies dropped it because it was “striking a balance between performance and price”…

    Can I interest you in some Kool-aid?

  • avatar

    Ferdinand Porche was doing this in 1900 with his wheel hub engined ‘System Lohner-Porsche’. Nothing new to see here. Interestingly, he added a gasoline engine to charge the battery in 1901. Imagine the level of refinement if 110 years of development had been invested in this concept! Here’s a pic for those interested.

  • avatar

    I like the idea, but it seems like it would significantly increase unsprung weight.

  • avatar

    If unsprung weight is a problem, why not reverse the build and use inboard motors acting on the drive axles but small disk brakes inside the wheels?

    In theory, the electric motors would require little to no regular maintenance/access compared to the brakes… though one advantage to electric propulsion is that the regenerative braking does a lot of the work, thus extending the life expectency of brake pads and rotors.

  • avatar

    You can avoid high unsprung weight by mounting both motor and brake on the body and connecting them to the wheel with a half shaft. A clever engineer should be able to combine them into one unit which would be lighter and more compact than a separate motor and brake. The downside would be extra complexity and cost and it would take up space within the body.

    • 0 avatar

      wouldn’t this defeat the purpose of having fewer mechanical parts? now you need CV joints, and space for the e-motors somewhere inside the car.

      not needing any propulsion system outside the wheels would enable us to create completely better functional cars. All current cars are build around a central power plant that needs cooling and also runs the brakes, AC etc. With wheel motors i can have flat floor-mounted batteries (low center of gravity) and the few auxiliary mechanicals (brake booster, AC) could be wherever i want.

      • 0 avatar

        You’re right; it’s a trade off. If a motor-brake unit can be made that is the same size and weight as a disc brake plus CV joint, putting it inside the wheel would be best. I just don’t know if it’s possible. Mounting them inboard is just an extension of inboard brakes.

  • avatar

    Now I’m logged in as Aaron Berba!

    ///Gunnar Nilsson

  • avatar

    Hmmm… Wiki says that NEMA Design B electric motors of 20-40hp are going to be in the neighborhood of 88% efficient, anyway. So, if the SIM is, say, 97% efficient, the range of a Leaf augmented by SIM (nominally 100 miles?) would be something like (97%/88%)*100miles or about 111 miles.

    I’d think there might be another 15% increase for eliminating the differential (a friend in the alternatie energy business tells me diffs are pretty efficient except when in a turn). Maybe 130 miles would be achievable with a SIM-augmented Leaf?

    There must be something else going on with the SIM-mobile that results in a 200 mile EV range.

    Massive battery? They limit the vehicle to a top speed of 25 mph? Both?

    If it affords better regen braking capability, then the SIM might account for more significant improvement in city range (but I thought recharge rates were mostly limited by the battery’s ability to absorb energy).

    So, I don’t think improved range due to SIM is going to suddenly make EVs practical. Of course, motor-per-wheel, individually controlled would make for a great AWD system, so it’s a useful advance.

    Still, we’re still waiting on major increases in battery capacity and recharge rates to get reasonable cross-country capability. Oh, yes, and reduction in battery cost.

    • 0 avatar

      You’re on the right track. Electric motors are already so efficient, that not that much can be gained by going to in-wheel motors. It certainly will not result in the kind of range increases projected by this outfit. It’s a classic case of comparing apples and oranges: this concept car is undoubtedly much lighter and certainly slippier than a Leaf, and not a production ready vehicle. In wheel motors will eventually likely find their way into EVs, but it won’t be that big of a breakthrough when they do.

  • avatar

    Obviously not a new idea, and every manufacturer planning EVs have it in development, or are already part of their road map. However, there are several problems that need to be overcome for it to be production ready.

    The real conundrum is that EVs with in-wheel motors requires a complete redesign of the suspension system. The motor requires their own cooling and even individual transmission within each wheel (most have a planetary reduction gear between the motor and hub), not to mention they are considerably bulky; which are hard to fit within the space provided by narrow 15-16″ tires that an range centric EV (Mitsubishi showed off EVs with in-wheel motors with 20″ wheels).

    The supplier NTN has probably the most mature design right now, and is expected to land a large contract with a major brand:

    Just as importantly, it requires a complete reorganization of the supply chain. As discussed previously on TTAC, EV supply chain means a lot less money for suppliers as it requires a lot less parts:


  • avatar

    If someone came out with a conversion kit they could make a mint. Start off with common make and models, rip out your drive train- drop in a battery tray and a harness/module package, replace the wheels – done.

  • avatar

    I believe Bill Lear’s last project in the 1970s was to put in-wheel motors on a bus. He thought a small diesel motor tuned for maximum efficiency matched to a bank of batteries would run a bus with much greater fuel efficiency than a conventional drivetrain. He ran into huge problems and died before those problems were solved. His heirs then pulled the plug on the project.

    I know one problem was durability of the in-wheel motor setup he was using, but there were other problems. Does anyone know or have heard heard of the other technical glitches Lear ran into? It was my understanding that with Lear’s track record, his efforts were being closely watched, especially by GM.

  • avatar

    Hrm, I was under the impression that the typical ICE car has ~20% drivetrain losses, and that’s with a torque converter, big transmission with loads of viscous drag and friction, differential and halfshafts, each with 2 cv-joints. I have a hard time seeing a car like the leaf or the volt having more than 15% drive-train loss, so doubling the range of a leaf seems like it’d take a lot more than just drive-train efficiency increase.

    • 0 avatar
      M 1

      Most ICE drivetrains are closer to the 12% range or thereabouts and you won’t see a huge variation between manual and autotragic (surprisingly). In the world of motorsports where you’re talking about power numbers and dynos and all that, 12% is a figure that won’t ever get you laughed out of the room or branded a snake-oil salesman.

      The worst of the worst are maybe 15%.

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