By on August 7, 2014

big_electric-supercharger-5-psi-vortex_ff184e8c0545dd8f299e7e2cc429699eBack in the heyday of import tuner magazines, there was an ever-reliable advertisement for some kind of “electric turbocharger”, generally the kind seen above. Much like the “10x pheromones”, one couldn’t help but wonder who was buying enough of them that buying ad space was worthwhile.

As dubious as those iterations may have been, the electric turbocharger may become a real technology used on the engines of the future. Valeo, a major supplier, is apparently readying an electrically-driven turbocharger that it says will be completely free of any lag.

While Audi is planning on using an exhaust-driven turbo with an electric motor to help spool the turbo faster, the Valeo unit is fully electric. But Automotive News reports two major concerns. The new electric turbos will consume lots of electricity, and they will only be ready for prime time when vehicles use 48-volt electrical systems.

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67 Comments on “Electric Turbochargers: Not Just For Tuner Magazines?...”


  • avatar

    LoL

    I had a Vortec V3 supercharger on my 2006 Chrysler SRT.
    Once you actually see a supercharger or turbocharger in real life you understand why these “blow dryer fans” are stupid.

    These things “should” do something technically because they blow air with slightly higher force into the engine, but the simple fact is that they don’t provide enough air pressure nor do they have the ability to vary that pressure. They turn on and blow at 100% all the time, providing less than 1 lb of pressure.

    On a side note, as I expected, “HELLCAT MANIA” is gripping my car clubs and these guys are either trading in old cars for “newer” Dodge Chargers*…

    Or they are trying to figure out ways to finance a $10,000 Supercharger/installation.

    If I was a full-time installer, this would be a perfect time to sdvertise low APR credit-card signups for Forced Induction mods.

    (* because must of their cars were purchased used and at high APR, they are underwater on their loans and can’t easily trade in for a newer car. )

    Anyone who makes the mistake of bringing electric turbochargers to a car show is getting LAUGHED AT.

    You would literally need an electric motor out the back of a Tesla Model S to generate/maintain the force of a cheap PROCHARGER.

    • 0 avatar
      319583076

      Gee BTSR, what’s a “Hellcat”?

    • 0 avatar
      calgarytek

      @darkwing.
      Are are are are are you, dddddd-darkwing duck?

    • 0 avatar
      Beerboy12

      the new trend in turbo’s is low pressure turbos. These little turbos only work in low rev situations and on small 3 or 4 pot motors to boost low rev torque. It is possible these electric turbos would be useful in this application because low revs do not provide much exaust.

    • 0 avatar
      pragmatist

      while it’s certainly possible that an OEM system might work, these aftermarket things are useless.

      Interesting footage of trying to build (for the heck of it) a supercharged system based on gas powered leaf blowers. They had to use 5 blowers to actually get an improvement on the dyno.

  • avatar
    Ooshley

    If it’s good enough for F1…

    • 0 avatar
      pnwrob

      F1 turbos are also used to generate electrical energy with excess boost these days.

      • 0 avatar
        niky

        The motor goes both ways. It can be used to spin the turbine, to eliminate turbo lag. Primary power still comes from the exhaust, though.

        What I’d like to see is an onroad application similar to the Mercedes Split-Turbo. Minimal heat transfer between exhaust and intake portions of the turbo, plus easier to package an electric center cartridge for both electrical power recovery and anti-lag.

  • avatar
    Pig_Iron

    Oh yes, 48v electrics, I remember those. They were going to be the next big thing, ten years back. Whatever happened to that?

    • 0 avatar
      psarhjinian

      One, we don’t want to kill first-responders.

      Two, it requires a re-think of the car’s entire electrical system, and costs quite a lot. There’s a reason a Prius as a normal 12V battery as well.

      • 0 avatar
        Ooshley

        48 V is nothing. Plus first responders manage perfectly well around all those volatile chemicals. I think they can manage.

        • 0 avatar
          tedward

          Multiple systems need to require the switch before the automakers could justify redesigning everything and disrupting the supplier contracts. Its the same issue with the cam-less engines that the Europeans are working on.

      • 0 avatar
        Sky_Render

        48V won’t do squat to you. Phone lines have a constant -48V on them, and I don’t see people dropping over dead when they plug telephones into the wall.

        • 0 avatar
          psarhjinian

          I should clarify: 48V at what amperage? I’d assume that shorting a 48V battery directly would be interesting…

          • 0 avatar
            Sky_Render

            Current is a function of both voltage and load (impedance or resistance).

            Now, if you’re asking what current a 48-V battery would put out in a near-short condition, I’d say “at least four times what a 12-V battery would.”

            :-P

      • 0 avatar
        zerofoo

        As opposed to the 100-200 volt batteries in hybrids or the 20 gallons of highly flammable liquids that we have roaming the streets now?

        48V of direct current is pretty harmless – even if the battery is capable of delivering lots of amperage.

        I’ve worked in data centers with 48vdc power. It’s pretty safe stuff.

        • 0 avatar
          Drewlssix

          Highly flammable liquids? Gasoline is not easily burnt til it is vaporized. You could drop lit matches into a bucket of gasoline all day with no worry. Well on a cool day anyway.

    • 0 avatar
      danio3834

      We haven’t switched yet because the entire automotive industry has been based around 12V systems for the last 60 years or so aside from a few exceptions. It will require a mass transition of equipment and design that the industry so far hasn’t seen as worthwhile aside from where necessary like Hybrid systems,. it’s sorta like the transition from Imperial to metric. We’ll see it eventually.

  • avatar
    psarhjinian

    Isn’t this really an electric supercharger, and not a turbocharger?

    As in, instead of being driven off the crank it would be driven electrically, whereas a turbo is driven by exhaust pressure?

    It’s not a bad idea; we already have electric power steering and air-conditioning units. It would certainly address the parasitic losses inherent in using a supercharger in a small-displacement engine. Assuming you’ve already got enough power to drive an idle-stop system, it’s not unreasonable.

    • 0 avatar
      sportyaccordy

      Yea, turbo implies turbine, which extracts energy from a moving fluid.

      Personally, I am waiting for the day that F1 electric hybrid turbo tech comes to road cars. The more free energy that can be recaptured the better.

    • 0 avatar
      HerrKaLeun

      You are right, turbo implies a turbine in the exhaust. Don’t forget, DK wrote this. So don’t expect too much detail and accuracy.

      WWII submarines and possibly other vessels used electric compressors for the same purpose. So this isn’t really new technology or technology reserved for garage tuners.

      • 0 avatar

        Valeo calls it a supercharger, the article references electric turbos as a broader technology. It seems like its neither fish nor fowl to me.

        • 0 avatar
          HerrKaLeun

          It is a charger, or compressor would be the aproppriate term as it compresses air.
          The turbine, or electric motor, or ICE direct drive, would be what drives the compressor.
          I don’t think turbo is a broader term outside actually turbine driven compressors. Most diesel and the old school gasoline compressors are turbos as driven by turbine. Everything else is not.
          Brayton cycles (jet engines) could be called turbos as well.

          To enginerers and mechanics it is very clear to be fish, there is no wiggle room. That is like saying diesel and gasoline engines kind of are the same since the laymen doesn’t really know the difference except that it uses differen fuel pumps when they fill the car.

        • 0 avatar
          Felis Concolor

          A supercharger is any device which increases the volumetric efficiency of an engine. At this time, there are 2 major types of superchargers: chemical and mechanical. I provided further breakdowns of the categories earlier, and the type of device described here would be an indirectly coupled mechanical supercharger.

    • 0 avatar
      bumpy ii

      Yep.
      “Valeo calls the device an electric supercharger.”

      Although having it be both would be fun. Electric motor to spool up the turbine at lower rpm’s until the exhaust gas flow is sufficient. Leave the motor coupled and use it as an alternator once the turbine spins up.

      In any case, cooling the motor would be interesting.

      • 0 avatar
        Barba

        That’s what Audi seems to be working on, two turbos with what they call an “e-booster” http://www.autocar.co.uk/car-news/new-cars/new-audi-sq7-use-electrically-assisted-turbocharging

    • 0 avatar
      MadHungarian

      In terms of reducing the parasitic losses from a supercharger, would it really? Isn’t there an inherent inefficiency in transforming the rotational energy of the crankshaft into electricity, via the alternator, and transforming it from electricity back into rotational energy in an electric supercharger motor? I think the question being raised here is that to generate a certain number of pounds of boost in an engine of a given number of cylinders and displacement takes a certain amount of energy, that you can probably calculate. You can make some decisions about where you draw that energy from and how you put it about the task of creating boost, but the energy requirement doesn’t change.

  • avatar
    Dirk Stigler

    And the Gods of the Copybook Headings said: you can’t gain efficiency by letting energy go out the tailpipe while making the engine do more work at the crankshaft.

    Electric superchargers offer the benefit of reducing boost lag and emissions by making the boost much more controllable, similar to the way electronically controlled wastegates reduced lag and improved emissions, efficiency and driveability. Against that, they give up the benefit of recovering waste heat from the exhaust and add what has to be a pretty significant load to the crankshaft output to generate electricity to drive them, not unlike a belt-driven supercharger. Energy is not free.

    Now, add a small battery pack (or at least smaller than what you’d need for a mild hybrid drivetrain) to decouple the electricity generation from the supercharger demand, and things may get more interesting.

    • 0 avatar
      Dr. Kenneth Noisewater

      So, install an exhaust-driven turbine and/or a Turbosteamer to recover that waste heat.

      And 48V is nothing special for even a conventional hybrid. Just hang a DC/DC transformer to service 12V accessories.

      • 0 avatar
        eManual

        You would need a DC-DC converter, as a transformer only works for AC to AC voltage conversion. The DC-DC converter may contain a transformer (or a coil) but needs extra circuitry, such as transistors/rectifiers/capacitors, etc.

    • 0 avatar
      Sigivald

      Reading more closely, it appears that this device is not using the electric motor to pump the main air charge (or rather the delta in air charge between engine suction and the desired volume) into the engine all by itself.

      It appears to be using it to keep the turbo at full RPM *while unloaded*, to remove turbo lag.

      That implies that the load in practice will be considerably lower than under the assumption that the electric motor is replacing the entire exhaust turbine.

  • avatar
    Fred

    Designing a motor to handle the heat of a turbo won’t be cheap.

  • avatar
    schmitt trigger

    “…and add what has to be a pretty significant load to the crankshaft ”

    This sentence is the key. Additionally the mechanical to electrical energy conversion in the Lundell (automotive) alternators is very inefficient further increasing crankshaft loads.

    Lundell alternators were designed back in the days when less than 1Kw output was required.
    Now that 5 or more Kw are required, there is an intense investigation to improve the alternator’s efficiency, or even replace it altogether with something else (like a direct crankshaft driven BLDC motor/generator)

  • avatar
    mnm4ever

    I did a little research into the electric turbo a few years back, and it was interesting and informative. It isn’t a bad idea actually, IIRC the problem is the boost wasn’t available for long periods. It was good for 1 or 2 runs at a dragstrip, but then it required time to recharge the battery to run it again. It didn’t just run continuously off the battery, it needed a separate power system to run at high enough speeds to make boost. This is fine for drag racing, but mostly pointless on the street.

    Seems to me it would make more sense to add a hybrid electric motor to add power, something like Honda tried with the first Accord Hybrid. I don’t see why it wouldn’t be possible through software manipulation to design the hybrid system to add both efficiency and enhanced performance depending on what you need at the time.

    • 0 avatar
      psarhjinian

      All hybrid systems can and do add power; it’s just not always advertised as such. It’s also not exclusive to increasing efficiency. Consider the Lexus LS600h and GS450h: in those cases, they’re very definitely adding power.

      Hybrids can do a few things:
      1. Run electric only under light loads
      2. Run the engine at it’s most efficient state, allowing smaller displacement and/or using the electric engine to fill in “holes” in the torque curve
      3. Run the engine at it’s highest output and then augment that.

      If you floor it in a Prius, you’ll see #3 happen—the power split graphic in the instrument panel will even show it. The Prius just isn’t terribly quick. You most certainly will feel it if you drive a GS350 and 450h back-to-back.

      Honda’s system in the (original) Accord Hybrid was different in that while it could do #2 and #3, it couldn’t manage #1.

      • 0 avatar
        tedward

        The problem they’ll have adding these to hybrids is that an electric motor driving the wheels can already torque fill for a turbo that is off boost. Still, I’m not an electrical engineer so it’s totally possible a gain could be managed over those systems or in conjunction with them.

      • 0 avatar
        FormerFF

        #1 depends on how much battery and electric motor is installed. Ford’s PHEVs can drive on battery only in any normal traffic situation. If you want a lot of acceleration the engine will be needed, but to just keep up with traffic, the electric drivetrain is plenty.

        • 0 avatar
          psarhjinian

          It also assumes you can decouple the engine entirely before the point where the motor provides assistance.

          I don’t think* the (early) Honda hybrids did that, I think they drove the crank directly.

          * I’m admittedly not sure—that may have been GM’s BAS.

          • 0 avatar
            bumpy ii

            Yes, Honda’s earlier IMA systems were directly connected to the engine. One of the advances of the current version in the Accord is that it can declutch the ICE and run on electric power alone.

  • avatar
    t0ast

    There actually is some legit aftermarket hardware out there already for the Toyobaru and Miata crowds (probably along with a few others by now). They’re good for about 5psi (tapering to 2-ish near the top end) and somewhere near 200 whp in both applications. Two additional batteries are required, but if memory serves, they can easily sit in the standard battery holder if you slightly downsize your original battery. General consensus so far is that those batteries have enough juice and recharge fast enough to easily handle anything short of track work.

    The kits are still a bit young and unrefined (like relying on physical throttle position to trigger), but community response has been largely positive and it seems to now be the easiest and least expensive gains available for these platforms.

    • 0 avatar
      mik101

      Do you have any more info on this? Sounds like a good read to me.

    • 0 avatar
      niky

      5 psi isn’t enough for 200 whp. Unless you’re saying it boosts the BRZ up to 200 whp. Which is probably what you’re saying.

      5 psi should be good for around 20-30 whp above whatever the stock BRZ makes.

      The old Knight kits had about 6-7 psi on a motor that size… and would have net you more than that.

      • 0 avatar
        t0ast

        Yes, end result, not gain. Most dynos are showing in the 190s on otherwise bone-stock vehicles. At that point, 200+ is just some exhaust bits and ECU re-calibration away.

        • 0 avatar
          niky

          The 3.5 kW motor seems a bit small for those gains, though I’m not conversant with how the efficiency of that brushless motor (it’s tiny) compares to the older custom-wound ones in the Knight kits.

  • avatar
    kvndoom

    I bought a throttle body spacer for the last truck I ever had. I didn’t get the 10HP* or the 20% MPG* it claimed, but it made an awesome sound.

    *”up to”. Obviously even zero percent is “up to,” hence Geico’s success, amongst others.

  • avatar
    turf3

    1) No way you are going to improve efficiency by adding a mechanical-to electrical conversion at the alternator and an electrical-to-mechanical conversion at the motor to drive the electrical supercharger, while at the same time giving up energy extraction from exhaust waste heat.

    2) No reasonable way to use exhaust waste heat to generate electrical power; turbochargers run at 50k rpm and up because those are the kind of rpms required for that type of gas turbine in that size; but generators do not produce power when speed is varying from a few k rpm to 50k rpm. (Yes, I know electrical generation stations use turbines; BIG BIG turbines that run at constant speed with very sophisticated controls on them.) And you still lose in the electric motor driving the electrical supercharger.

    3) Turbochargers consume a LOT more power than you think. A buddy of mine worked for years as a senior development engineer in turbochargers. I think he told me a turbo for a 200 HP auto engine might consume on the order of 50 HP to compress the intake air charge. Why does this work? Because the power is available for a low cost, in the exhaust gas. Has anyone here ever SEEN a 50 HP electric motor? Typical 3 phase AC motors at 50 HP would be around 18″ long, 18″ diameter, and would weigh 50-100 lbs. This is with copper sized for 208V supply. For 48V supply, the copper in the windings would be even bigger (heavier, more $$$) due to increased current being carried.

  • avatar
    CowDriver

    This reminds me of a hack I tried on my first car (a 1951 DeSoto), back when I was in high school. The blower for the heater/defroster was at the very front of the engine compartment. I fabricated a duct (using cardboard and epoxy) from the blower to the carburetor. I was terribly disappointed when I found no performance difference between having the blower on or off.

  • avatar
    Madroc

    I’ve actually wondered why no one has tried the opposite: put a clutch pack on the alternator (or remove it altogether if you’re getting enough juice) and generate electricity with an exhaust turbine. Use all that waste heat and take a load off the engine.

    There’s surely a sound engineering reason why this is a bad idea, I just don’t know what it is.

    • 0 avatar
      LeMansteve

      IIRC, BMW has experimented with generating electricity from exhaust heat. It’s not as easy as it sounds.

      Mazda uses a variable voltage alternator in their i-eloop system. Not quite an on/off clutch system, though.

  • avatar
    carve

    This would be an electric supercharger, but I think the electric turbocharger is a design with merit.

    During normal cruising on a turbo car, the wastegate is open and the turbo is just sitting there because extra power isn’t needed. This not only creates lag, but it also doesn’t extract any extra energy from the exhuat- it’s just wasted. How about instead we imbed some magnets on the shaft and have some stationary coils around it and extract some electricity, which can be used to power an electric motor driving the car? Since your wastegate is closed and all the exhaust is going through the turbine, it’ll already be spinning faster and lag will be reduced- you just turn off the generator. Of course, you don’t want the compressor soaking up all the energy, so you’ll probably have to find a way to de-clutch it from the turbine. Perhaps a planetary gearset between the turbine and compressor, with the turbo-alternator in the middle. When boost is called for, the elctric motor goes into drive moad and helps the turbine spin things up, further reducing lag.

    The 1989 Mazda TD-R Concept used turbo-alternators I believe. Cool concept car. I can’t find anything on the internet about it beyond a pic and the name, so I’m just remembering the turbo-alternator thing from a Popular Scinece I read when I was 12.

    God I love the internet. Page 48 of the Feb 1990 Popular Science. The picture is of the Mazda (which is a cool rally-racer concept that still looks good), but the caption was for an isuzu concept diesel engine which used exhaust turbine alternators…

    http://books.google.com/books?id=f6nAZ0VHIQgC&pg=PA48&dq=Mazda+TD-R&hl=en&sa=X&ei=tcfjU4rpOtLb8gGEkICoBQ&ved=0CCoQuwUwAA#v=onepage&q=Mazda%20TD-R&f=false

  • avatar
    nickoo

    This is stupid. Adding an electric motor into the drive train for additional torque makes more sense than this. Or, even better, active waste gates, twin scroll in normal turbos, or simply positive displacement superchargers are all better options.

  • avatar
    PandaBear

    With the consumption of that much electricity when turned on, why not just put the power down via electric motor? Oh wait, that’ll be a hybrid.

    I think the only way for this to work is if it is a compress air pump and storage. You pump air into storage (electric or via turbo), cool it, and then release it when you need the boost.

    • 0 avatar
      carve

      That’s an interesting idea. If we could vary valve timing enough, we could even do an extreme Atkinson cycle under light load and let a good portion of the compression work be done by the turbo instead of by the motor. Just the in-cylinder compression takes an enormous percentage of a motor’s output. Under light load, you could also use an interheater to recover a bit more of the energy. Open the intake valve and instead of the piston having to work to suck in air, it’ll be pushed down by moderately hot, moderately compressed air. Add just enough heat to keep it just below detonation point, which could be quite a lot at part throttle on Atkinson cycle.

      • 0 avatar
        Fred

        Another point is that the charger boost could be controled by the computer via the motor speed, which should be more flexible than a wastegate. Eeking out a bit more efficiency.

    • 0 avatar
      nickoo

      You’re talking about a jet assist. Its already done in my industry for when the turbo needs to provide an instant boost. Doesn’t make sense in cars as they don’t carry onboard compressors.

  • avatar
    Slow_Joe_Crow

    The Audi project to use a motor to eliminate lag is appealing but an electrically powered supercharger seems like spitting in the wind of thermodynamics. How about turbo-compounding as used in some aircraft engines?

  • avatar
    Beerboy12

    Well… if power steering and air conditioning have gone electric, why not the turbo / super charger?

  • avatar
    Big Al from Oz

    An axial flow compressor would be far more efficient when working in conjunction with an electric motor.

    With an axial flow compressor it will be far easier to control the airflow through the compressor at each stage using CVG’s.

    I really don’t think generating additional energy and negating the use of existing/wasted energy is a smart move.

    What I do imagine is the augmented energy from the electric motor will only be available until sufficient exhaust flow is available. Once this occurs I would suspect the boost to the supercharger will then become a turbo charger.

    The electrical energy will only be required for short durations.

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