By on November 5, 2014

Valeo Electric Turbocharger

Though full electrification might not be in the cards for most consumers, those looking for turbo power for their vehicles could find a little bit of that black magic in the turbo itself down the road.

A report by Navigant Research posits that the best way to eliminate lag without using a supercharger to make up for said lag — at the expense of increased friction at higher speeds — an electric turbocharger may be the best bet yet. The technology offers a handful of improvements over exhaust-driven units, including packaging of components, responsiveness and flexibility.

Supplier Valeo recently unveiled such a piece — for 12V and 48V electrical systems — with the first applications coming online in 2016. According to their findings, the best application for the turbo is with an engine that uses cylinder deactivation to maintain fuel economy. As power is reduced with cylinder count, an electric turbo can help with small boosts in power to tackle situations that would otherwise switch all of the cylinders back on, such as mild-and-above inclines.

Meanwhile, engineers wouldn’t have to figure out where to package all of the plumbing required for an exhaust-driven turbo with an electric unit, allowing for a placement that provides the best peformance and setup.

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45 Comments on “Report: Electric Turbocharging Could Provide Fuel Economy Boost...”


  • avatar
    Lie2me

    Very interesting article. Turbo-lag has been one of my big issues with turbocharged engines, if that can be reduced or eliminated it would certainly make a convert out of me

    • 0 avatar
      Nicholas Weaver

      Of course, you don’t just have it be electrically driven, you also have it be a generator as a classic turbo not just an electrically driven supercharger: When you need more boost you drive it forwards, when you need less you scavenge energy: if the wastegate ever opens, somethings wrong.

      As a bonus, if Honda/Mercedes/Nissan/Ferrari is the first to bring that version to market, they can advertise it as Formula 1 technology…

      • 0 avatar
        Conslaw

        @ Nicholas Weaver

        The generator concept does seem to be superior. Matched with various levels of electric drive, you could have large vehicles with small engines but plenty of power and torque and much less wasted energy.

        • 0 avatar
          redav

          It doesn’t even need electric drive to benefit. A system like Mazda’s capacitor would permit disconnecting the alternator when the turbo operates as a generator.

      • 0 avatar
        Dr. Kenneth Noisewater

        Indeed, this is what the Volt should have had, coupled with an Atkinson cycle motor and wide-ranging fuel injectors, so that you could operate in Atkinson efficient mode for much of the time, while enabling Miller mode for high-demand situations. So, basically, you’d have a 1l 3cyl 50+mpg 25-35kW motor for steady-state highway driving, and a 100kW+ Miller motor for hills and high-speed shenanigans.

  • avatar
    kvndoom

    “As power is reduced with cylinder count, an electric turbo can help with small boosts in power to tackle situations that would otherwise switch all of the cylinders back on”

    Then why even have the extra cylinders in the first place?

    • 0 avatar
      Lie2me

      For the bigger boosts in power

    • 0 avatar
      That guy

      This has the ability to run like a lightly boosted 4cyl at light loads and a moderately boosted 8cyl when you drop the hammer down. It’s another step forward in having major power without the heavy fuel penalty.

      An example would be adding this to GM’s 5.3L Silverado. It would be able to pull a higher OD gear in 4cyl mode because the smart turbo would give it some boost when needed, improving highway fuel economy. When you need power (towing, passing, etc) it would be able to provide enough boost to make power that would embarrass the already stout GM 6.2L.

      • 0 avatar
        Lie2me

        If this works as you say, I’m in

      • 0 avatar
        ECarGuru

        I’m betting you’ll find that it can lightly boost a 4 cylinder and won’t be able to keep up, let alone moderately boost an 8. I’ve seen a couple of electric turbo charger concepts in the past, but none in the 12v range. Most where 100+V that used exhaust scavenging or something similarly clever to recharge.

        Think of it this way, if a supercharger needs 50+hp (v-8 moderate boost) an electric turbo will too.

    • 0 avatar
      stuki

      ….bragging rights…..?

  • avatar
    mcs

    I wonder if they’ll add logic to detect the EPA test cycle and keep the thing shut off during the test.

  • avatar
    HerrKaLeun

    Where is the turbine? Why do people call chargers without turbine “turbo”?

    Some accuracy in using technical terms would be great. I can get slang terms on USAToday. This is TTAC where in the past journalism was superior.

  • avatar
    Shipwright

    They did it! they finally managed to fit an electric hair dryer to a car engine. All kidding asside, it’s sounds like a good idea, no lag and no heat problems.

    • 0 avatar
      JMII

      If it works for F1 then hey why not. The concept is simple, the only problem is you need a lot of juice to pressurize the air. 12V ain’t going to cut it. I believe F1 is using their system to augment normal turbo charging (exhaust driven) and to reduce lag. This is different.

      Someone posted awhile back that you can already get an electric supercharger for your FR-S:
      http://www.ft86club.com/forums/showthread.php?t=39719

  • avatar
    turf3

    My understanding of the “electric turbocharger” is that the electric motor is only used to accelerate the rotor up to partial speed. The serious work of compressing air is still done by the exhaust turbine. If you tried to replace the exhaust turbine with an electric motor altogether, the power draw would be on the order of 40 HP or more, which would require on the order of 50 HP draw from the alternator, plus there would be the size of the motor. I guess it would be 2 or 3 times the size of the alternator. And the cables to it would probably be two or three times the diameter of battery cables. But a small motor to accelerate the shaft up to partial speed, thus reducing turbo lag, would make some sense.

    By the way, a “turbocharger” is correctly termed a “turbo-supercharger” though no one uses that terminology any more. It consists of a turbine, which extracts energy from the waste heat in the exhaust, and a compressor which compresses the charge air. If you replace the turbine with mechanical drive (either by belt from the crankshaft or an electric motor) you have a “supercharger”. If you use an electric motor to assist the exhaust turbine you have an “electrically assisted turbocharger” not an “electric turbocharger”. The term “electric turbocharger” is inherently self-contradictory; if there’s no turbine there can’t be any “turbo”.

  • avatar
    Stumpaster

    Then it is not a turbocharger but is a supercharger.

  • avatar
    Conslaw

    If you need 40-50 horsepower to drive a supercharger full out, most hybrids generate that much power for their electric drive motors. If you shift that horsepower to forced induction for the ICE, you could have one fast Prius on your hands. Of course, you engine would have to be racing-spec to handle the power, but why let practicalities rule one’s imagination?

  • avatar
    TW5

    Is there any reason to make an electrical turbo-hybrid system, rather than using compound turbocharging with a BAS hybrid system? If you’re going to have energy recapture and electrical motors onboard, why not hook everything up to the crankshaft?

    • 0 avatar
      jetcal1

      TW5,
      why not go full bore and go to sleeve valves which eliminate detonation as well?
      Of course, we just built a ludicrously expensive engine, but think of the power or the economy.

  • avatar
    Luper

    Volvo recently used an electric turbo-charger (or whatever the B&B decide to call it) on a one-off prototype 2.0L 4-banger. The electric turbo was used to spool up two conventional turbos, thereby eliminating turbo lag (reportedly). They also claimed said motor delivered 450HP. Yowza.

  • avatar

    On the first glance this seems bogus because the electric energy to drive the turbopump comes from the power produced by the engine, whereas in traditional turbocharger the otherwise wasted energry of the exhaust gases is used. Scavenging the waste heat is what drives the research in exotic extra-expansion engines (such as “5-cycle”) or the BMW’s steam-compound engine. From the elementary thermodynamic considerations, this devices could help a lot with the turbo lag, but will not help efficiency at all.

  • avatar
    wmba

    I invented just such a system in 1988, with parallel air flows from what was termed the Electrocharger and a regular turbo. A spring-pressure activated vane at the V junction allowed whichever air stream was stronger to use the vane to close down the path from whichever compressor produced lesser dynamic flow. When the turbo was really puffing, the vane would close off the pipe from the electrocharger, activate a microswitch, and through a control system turn off the electrocharger’s motor.

    No doubt dozens of other people have had similar ideas for decades. It is hardly revelatory. The problem that stopped me was the huge horsepower required to operate the electric motor, the gigantic wiring needed for thousands of amperes at 12 volts, and how the battery would react to almost short- circuit conditions repeated time and again.

    I’m going to be most interested to see how this thing works in practise.

  • avatar
    marc_aus

    Isn’t this similar to what Audi put in the RS5 TDI concept? In that case providing pre-boost before the ‘real’ turbos come online.

    http://autophorie.de/wp-content/uploads/2014/05/audi-rs5-tdi-electric-turbocharger-3.jpg

    Particularly useful to alleviate traditional turbo lag…

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