By on April 14, 2015


Coming soon to an Audi near you is Valeo’s electric supercharger, which will help boost engine acceleration while improving fuel economy.

Automotive News Europe reports the supercharger will likely find itself sharing space with the engine of the upcoming Audi Q7, with other automakers testing out the technology according to the French supplier’s COO Christophe Perillat-Piratoine.

The supercharger uses an electric motor to introduce more air into the engine, leading to better acceleration without the lag found in turbocharged vehicles. Valeo adds that its technology can also reduce fuel consumption by 7 percent to 20 percent, though higher costs and power consumption are drawbacks.

The technology is likely to go head-to-head with hybrid powertrains using electric motors to overcome lag, such as those found motivated the McLaren P1, Porsche 918 Spyder, Ferrari LaFerrari, and Acura NSX. The BMW i8 uses a similar setup to Valeo’s tech, with power derived from an electric starter-generator activated during engine startup to offset the turbo lag on the 1.5-liter turbo-three.

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16 Comments on “Audi Set To Use Valeo’s Electric Supercharger Technology...”

  • avatar

    Disclaimer: I am not a physicist, nor do I remember any, really, of what I took in high school. That said, how is it more efficient to route engine power through the alternator and into a battery, and then use the battery’s energy to power a supercharger, rather than just connect the engine directly to said supercharger? Because it seems like the more steps you introduce between the source of the power and the turning of the supercharger, the less efficient it becomes. So, does the increased fuel efficiency result from lower overall power production, or is there some other math/engineering explanation that someone can explain to a dunce like me?

    • 0 avatar

      It’s a matter of inertial load.

      Hook that supercharger directly to the crankshaft and it joins the direct inertial loads of the crankshaft, rods and pistons, and by the crank’s timing link to the camshaft, indirectly to the inertial loads of the entire valvetrain as well. All those moving parts have to be strengthened to sustain those loads, which adds weight and expense.

      Now connect that supercharger to an electric motor, and the motor takes on only the inertial load of the supercharger. Less loads and stress, which allows all those parts rotating in the crankcase to run without parasitic losses from the supercharger. Adding an extra motor to the car actually reduces complexity in the long run.

      • 0 avatar

        Aren’t you just moving the inertial load from the supercharger pulley to the alternator since the alternator would need to generate more power?

        The primary advantage I see is that the output of the supercharger is not tied directly to engine RPM like a traditional supercharger, or exhaust gas pressure like a turbo. It could be electronically controlled.

    • 0 avatar

      I am thinking it is because the battery used to power the supercharger can be replenished by energy recuperation similar to what EVs/hybrids do.

      • 0 avatar

        ‘Super caps’. no battery. they charge extremely quickly and discharge even faster.

        • 0 avatar

          Looks like one of Valeo’s implementations is 2KW @ 12 volt, i.e. 170 amps; average time on is 7 seconds. So, that’s within starter motor territory, i.e. not out of line for a car battery.

    • 0 avatar

      I think the advantage is selective use of the supercharger. Having it cut out when it’s not needed will save more energy than a belt driven supercharger and maybe even save gas compared to something passive like a turbo. And that’s before you toss in lag.

      It will need a big plunger switch on the shifter like in Mad Max to be really cool, though.

      • 0 avatar

        Superchargers are drags on the system all the time. turbochargers freewheel until enough exhaust flow is applied to push the boost. I would imagine an electric supercharger is more akin to a turbo than a traditional supercharger in that it’s an on-demand device.

        I’ve owned both turbo’d and roots-type blower supercharged cars. the drag is there with the blower

        • 0 avatar

          “driving” in congestion Tokyo with my supercharged Jaguar is a miserable experience of average speed less than 12mph, and 11mpg, the blower is rotating for only purpose to burn more gas and heat the engine bay that I wish to disable it together with 6 out of 8 cylinders. This is a brilliant idea.

    • 0 avatar

      From what I’m imagining, this would use regenerative braking to charge the battery that runs the supercharger, in conjunction with a turbocharger. So the whole process would utilize waste energy, resulting in net energy savings (especially at slow speeds and low engine loads)

    • 0 avatar

      They could actually make it more efficient by driving the alternator via “free” kinetic energy from the exhaust gases. Extend a drive shaft from a turbo charger to an alternator/motor. I believe the F1 powerplants are setup this way. No?

  • avatar

    Barge need MOAR acceleration. (facepalm)

  • avatar

    “can also reduce fuel consumption by 7 percent to 20 percent”

    “though higher …. power consumption are drawbacks.”

    The first and second halves of that sentence don’t agree. Are they actually trying to say you need a bigger alternator? Also in their list of cars with “lag” I believe only the P1 has forced induction. Sounds like they’re just name dropping.

    • 0 avatar

      I believe that reduction in fuel consumption is referring to a comparison with a typical belt driven charger. Even when electronically clutched, there is still some power loss associated with the mass of the supercharger on the belt. Those parasitic losses from the belt are eliminated when it’s all electric so low-load and partial load situations improve the systems economy.

      Sure it’s a higher electrical load when the SC is powered, but as the engine comes up in RPM, the altenator’s increased output can cover the load. The system would only be “on battery” a fraction of the time until the RPM’s raised the available amps.

  • avatar

    The way I understood it is that the electric motor is used only to spin the turbocharger’s wheel up to speed more quickly than can be achieved by the exhaust gas turbine alone.

    If you used an electric motor as the only source of power to drive a supercharger, you would probably need something on the order of a 20+ HP motor. A 20 HP motor on a 12VDC system for continuous use would require power cables twice as thick as your thumb (1250 amps!), and would be very heavy and large.

    This is why turbo-superchargers have largely supplanted engine-driven superchargers. The engine-driven compressor takes shaft power that could be used to drive the car, whereas the exhaust gas turbine driven compressor takes waste power from the exhaust gas, that would otherwise be lost. Add to that the inefficiencies inherent in the engine-alternator-battery-electric motor chain and you can see the end result.

    Claims of fuel consumption improvement should be disregarded. Think of the path that this, probably subtle and complex, technical information has to follow:

    – Test engineers perform the test and get results that are probably less than totally conclusive and are highly dependent on a specific set of operating conditions.
    – Engineering management creates .ppt file for non-technical management
    – Non-technical management decides to herald the test results
    – Public relations department (staffed by liberal arts majors) writes up a press release.
    – Marketing management reviews press release and edits several times
    – Press release given to automotive press
    – Reporter for “Automotive News Europe”, who has minimal technical background, takes press release, rewrites it
    – Editor for “Automotive News Europe” edits it and makes some changes

    So there probably were, once upon a time, some real data on fuel consumption with/without this device, that showed a favorable result under certain conditions; but who knows what they really were.

  • avatar

    I’ve looked into this and thought about it and done some rough calculations, looked at the commercial items available from time to time and the various youtube instruction videos, and come to the conclusion that you really need a mammoth blower, as far as electric blowers go, and the battery to cope to make it workable; not too good a choice for the backyard mechanic, but something AUDI could do. I can’t wait to see it; when they start ending up in junkyards might make a great source of parts for the homebrew.

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