VIDEO: How Volvo overcomes turbo lag in its engines

Turbo lag, or the delay between summoning acceleration via the car’s throttle and the response from the engine, is a perennial challenge for engineers developing turbocharged engines. With the latest PowerPulse engine from Volvo, the Swedish brand claims to have found a solution to turbo lag, and a simple one at that.

Put simply, the turbocharger draws energy from exhaust gases which drives one turbine connected to another on the intake side, which forces a denser intake charge – hence, forced induction – for more oxygen and eventually higher engine outputs.

Because it takes time for the turbocharger to spool up from a state of lower engine revolutions and thus lower exhaust gas flow rates, there will be a delay between throttle input and engine response, which is what we know as turbo lag.

Volvo’s solution here for its turbodiesel engine is to have a tank of compressed air fed by an electrically driven air compressor, fed from the air intake filter. This compressed air awaits throttle input, and is then injected into the exhaust manifold side of the turbocharger to help spool up the turbine.

For its forced-induction petrol engines, Volvo employs both supercharging and turbocharging to eliminate turbo lag. Here, the mechanical supercharger takes the role of the electric air compressor in the aforementioned turbodiesel, as it spools up more instantly than the exhaust-driven turbocharger. In the T8 Twin Engine variants, any lag in response is further alleviated by the presence of electric drive assistance.

The presence of Volvo’s air compressor-assisted turbocharger is made possible by the increasing electrification of its models, with modular battery packs that will fit the company’s Compact Modular Architecture (CMA) and Scalable Platform Architecture (SPA) platforms.

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Mick Chan

Open roads and closed circuits hold great allure for Mick Chan. Driving heaven to him is exercising a playful chassis on twisty paths; prizes ergonomics and involvement over gadgetry. Spent three years at a motoring newspaper and short stint with a magazine prior to joining this website.

 

Comments

  • tokmoh. on Dec 13, 2017 at 2:47 pm

    Volvo > all

    Like or Dislike: Thumb up 15 Thumb down 6
    • Ah Seng on Dec 13, 2017 at 3:25 pm

      Lots of mechanical and technical problem.

      Like or Dislike: Thumb up 11 Thumb down 15
      • Michelle Tan on Dec 13, 2017 at 6:34 pm

        Thats why pakcik said it has > problems

        Like or Dislike: Thumb up 5 Thumb down 7
        • Audi Fans on Dec 14, 2017 at 5:42 pm

          That’s why the problem is >>> you only

          you are living in a dinosour world going about daily life using dinosaur obsolete technologies proiducts

          Looks like you’ll never learned to improve with advancement in technologies with time>> in other words you are an outdated person and still living inside a CAVE !!!

          Like or Dislike: Thumb up 4 Thumb down 1
          • Kunta Kinte on Dec 15, 2017 at 5:07 pm

            Very well said. Has anyone here ever driven a twincharged Volkswagen? That engine has both a supercharger and turbocharger. No turbo lag whatsoever, and the power output is phenomenal for a tiny 1.4 liter engine. State of the art. Only laggards, boring and old outdated people drive their underpowered sluggish Toyota’s thinking That’s heaven when they have never tasted nectar.

            Like or Dislike: Thumb up 2 Thumb down 2
      • Dislike Toyota on Dec 15, 2017 at 2:18 am

        I think this applies to Toyota .

        With outdated technology and dinosaur in nature especially engines .

        Look at present Toyota design , makes me want to phuk…..

        Like or Dislike: Thumb up 0 Thumb down 1
  • With more parts, the more probability of a failure and more expensive repairs, esp with the compressed air on the turbo-diesel engine.

    What Mazda did to reduce turbo-lag was to engineer a simple-solution via its Dynamic Pressure Turbo, a combo VGT and Twin Scroll solution. Use a valve to divert low rpm exhaust to a small orifice to spool up the turbine faster. At high rpm, open the valve to divert high exhaust to a larger orifice. Simple!!

    Like or Dislike: Thumb up 9 Thumb down 10
  • 12yrsold on Dec 13, 2017 at 5:09 pm

    It is simple yet complicated. Sound gud yet not necessary true. Ever system has its merits yet will have its inherent problems of mechanical failure due to wear & tear.

    When VW use the TSi engine, they found that its not useful in the lower RPM range hence the term turbo lag comes in. They add a supercharger to mitigate the lag.It sound brilliant at that time.

    Its been used by the 1st generation of TSi(Turbo Supercharger injection) or twin charge engine by VW group. Is it a failure !? Ask VW why they revert back to single turbo charge engine Now.

    Lets hope this New engine/system employed by Volvo give a better view of what is next to come. Am sure it can only get better with time bcos human learn from its mistakes.

    Like or Dislike: Thumb up 9 Thumb down 1
    • I though TSi means Twin-charge stratified injection?.

      The Golf FSi stands for Fuel Stratified injection. Which is direct injection system.

      Like or Dislike: Thumb up 0 Thumb down 0
    • Kunta Kinte on Dec 15, 2017 at 5:12 pm

      Dude , TSI means turbo stratified injection. VW reverted to a single turbo because the twincharged engines were too costly to produce. Those who still have one should keep their twincharged cars, it’s an engineering marvel and collectors car.

      Like or Dislike: Thumb up 1 Thumb down 0
  • Please don’t be another place that shoves EE videos in my face. I’ve had enough of that from carthrottle, drivetribe, jalopnik, youtube sub etc etc.

    I was hoping paultan would do their own journalism.

    Like or Dislike: Thumb up 5 Thumb down 1
 

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