You can sign us up for this one. Volvo is testing a prototype S60 sedan equipped with a Formula One-type Kinetic Energy Recovery System (KERS) at its Sweden headquarters and recently took some folks from Green Car Reports for a test drive.

While noting that the KERS' rear-axle mounted flywheel that stores braking energy and transfers it to the drivetrain could be loud, Green Car Reports unmistakably enjoyed the experience of the extra kick the system provided to the car's 2.5-liter turbocharged engine. In short, the S60's KERS system adds 80 horsepower to the car's 254 and, as a result, cut about a second and a half off of the car's usual 0-100 km (62 miles per hour) acceleration time of about seven seconds.

Three years ago, Volvo was awarded a $1 million Swedish government grant to develop such a system and, early on, said KERS could cut fuel use by as much as 20 percent. Volvo said last month that it had a prototype in the works.


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  • 29 Comments
      goodoldgorr
      • 1 Year Ago
      Beware of any system that add cost to a car or truck. This is just a trick to make more money. Hybrid, kers, batteries, chargers, renegerative breaking, etc are a gimmick and a fad. Only right move on technology is better like for exemple electronic watchs versus spring mechanism, or transistor versus lamps, or compact disk versus vynil disks. The future is hydrogen fuelcell and green algae farming and synthetic nat gas and winmills systems and solar power systems. Only these systems have been postponed for big oil interests. After that cheap , over the ground trains-metro going everywhere might be cheaper and faster then cars. there is no more reasons to get bugged by the idea to have a personal cars, get clogged in traffic and have to drive and find parking etc. Confortable metros with tv and computer are faster and better. Long vacation for cheap at long distance each weekends is the best. For the isolated houses taxi driven by employees is good. In leisure time peoples loving to drive might get used cars from 1920 till today to get exercises and visit the country.
        me_myself3
        • 1 Year Ago
        @goodoldgorr
        And bicycle with wooden rim from afar to that place. The optoelectronic multitude of utilizations will transport above soily ground. Excuse me, I now need to take a dump.
      2 wheeled menace
      • 1 Year Ago
      electro chemical storage is not bad at all. 95-99.9% efficiency isn't good enough? Gasoline loses that much energy from the well to the pump just being pumped / shipped.
      2 wheeled menace
      • 1 Year Ago
      Lol. Gas engines are just getting more and more complex. Meanwhile the electric motor continues to get by with just 1 moving part..
        EVnerdGene
        • 1 Year Ago
        @2 wheeled menace
        "1 moving part" always make me chuckle. Does that mean simple, very few parts, inexpensive ? Take a look at the size and complexity of this VW XL1's 5.6kw-hr pack (I hope the motor driver, controls, and charger are integrated into this huge package - [in front of the passenger]) http://www.wired.com/autopia/2013/03/volkswagen-xl1/#slideid-55612 Imagine a 4+ times bigger pack in the Leaf, or the 15 times bigger pack in the 85kw-hr Model S. - - - Chevy Volt pack http://www.compositesworld.com/articles/chevy-volt-battery-pack-rugged-but-precise in an interview - GM engineer said there are 600 seals in this assembly.
      BipDBo
      • 1 Year Ago
      This thing adds a whole bunch of mechanical complexity to the car. I'm usually leery about complexity like this, especially with CVTs. In this case, it wouldn't bother me because even if the whole thing breaks down, it won't leave you stranded. The car would likely still drive normally, but with a little less efficiency and performance. My understanding is that this thing is not very heavy. I don't know the weight of the entire assembly but the flywheel weighs only 13.2 pounds. It's also pretty compact. Packaging and weight impacts might be less than drive shafts that provide AWD and almost definitely, batteries and motors found in a typical hybrid.
        Ele Truk
        • 1 Year Ago
        @BipDBo
        Lightweight flywheels mean they have to spin really really fast (60,000 RPM). How long do bearings last at that speed?
          EVnerdGene
          • 1 Year Ago
          @Ele Truk
          the flywheel probably runs in a vacuum butt, overall, it looks complex, big, heavy, and expensive L^4
          matal341
          • 1 Year Ago
          @Ele Truk
          The energy can be stored for a period of 30 minutes.
          EVnerdGene
          • 1 Year Ago
          @Ele Truk
          "The energy can be stored for a period of 30 minutes." With an exponential decay?
          Pandabear
          • 1 Year Ago
          @Ele Truk
          bearing speed, like piston speed, depends on the contact surface speed. If they want it to run fast they can make the bearing real small in diameter and run lower linear speed on the surface. There's also fluid bearing that last much longer than ball bearing with reduced load capacity.
          BipDBo
          • 1 Year Ago
          @Ele Truk
          Bearings can be engineered to last effectively forever. What happens though, if for instance, the case leaks introducing air and moisture? The system not work very well. What about if that moisture gets to the bearing and they start to wear? A 60,000 rpm wobbly flywheel sounds fun.
      paulwesterberg
      • 1 Year Ago
      A 20% improvement is not much. If you take a car that gets 35mpg you could improve its mileage to 42mpg... About the same improvement as most electrical hybrid systems. The problem with this is that you cant add more capacity to make it a plugin vehicle.
        Pandabear
        • 1 Year Ago
        @paulwesterberg
        but it should be cheaper, weight less, and last longer than electric hybrid's battery.
          matal341
          • 1 Year Ago
          @Pandabear
          Dave D The specs are already out. The flywheel weighs 11 pounds, the whole system, including the Continuously Variable Transmission (CVT) add 132 lbs to the car. It puts out up to 80HP and adds up to 25% (not 20%) to the car's fuel economy. It drives the rear wheels only and therefore the car is actually an AWD. The kinetic energy can be stored up to 30 minutes. Volvo doesn't really brag, that's why you didn't hear it.
          2 wheeled menace
          • 1 Year Ago
          @Pandabear
          Yes, instead of replacing the $800-$2,000 hybrid battery, you can replace a CVT transmission, bearings, fluids, etc. Uh sure, that'll be cheaper ;)
          EZEE
          • 1 Year Ago
          @Pandabear
          And be aero! :D
          Sean
          • 1 Year Ago
          @Pandabear
          @matal341, could you post a link about the weight because everything I could find put the disc alone at 13 pounds. http://www.extremetech.com/extreme/154405-volvo-hybrid-drive-60000-rpm-flywheel-25-boost-to-mpg
          Dave D
          • 1 Year Ago
          @Pandabear
          If that's true, then they should release specs about the system: Weight, cost, longevity, etc. What you say could well be true, but I've never seen a company be shy bragging about their advantages. So....let's here it. I'd love for all of that to be true and have yet another path to better fuel economy. But I'm a bit skeptical until I see details....and as Paul pointed out, it can't be upgraded to a plug-in.
          skierpage
          • 1 Year Ago
          @Pandabear
          But a hybrid's battery powers accessories a lot more efficiently than engine-driven and then the car can shut off at a standstill. A battery stores energy for days instead of 30 minutes, so you can drive around the next morning partly electric while this Volvo is 100% gasoline. This is just a complicated distraction from the inexorable electrification of the car, and Volvo doesn't have the engineering depth to waste on it, with or without government money.
      q`Tzal
      • 1 Year Ago
      Mostly agree on electric energy storage being better ... with one situational caveat: from an engineering and physics standpoint we know that energy is lost in conversion from one form to another, like mechanical to electrical to chemical and back again. The allure of flywheel storage for inertial energy is that after it passes through just as many energy wasting metal gears as the electrical equivalent there are no more efficiency losses. Batteries loses energy at rest as do flywheels. A more apt analog would be an inertial super-capacitor: both are optimized for high power bursts in and out and are poor at long term storage. I'm looking forward to the spectacular failure modes of flywheel storage in a platform that TURNS and maneuvers while braking. I seem to remember NASA experimenting with flywheel prototypes and even their "safe" carbon fiber wheels failed explosively. I'll be neat if Volvo solved this.
      Schwy
      • 1 Year Ago
      330+ HP and still return better fuel economy than my Mazda 2.5L. I'm in.
      goodoldgorr
      • 1 Year Ago
      Im not interested to buy personally as I do mainly highway traffic. but taxi doing frequent breaking might save a lot of gas and also this system work as good in heat and cold contrary to batteries. Also this system for garbage truck might be wonderful.
      Dave D
      • 1 Year Ago
      I've skimmed every article and press release I could find about this. They are saying nothing about weight of the SYSTEM. Sure, the carbon fiber flywheel is only 6kg, but one glance at this picture and you know that is a rounding error on this bad boy. There are batteries out there (like the SCiB) that can do 10,000 cycles that will do just fine for a system like this and it doesn't require a CVT, a differential, an output gear train and a vacuum pump. This looks like a lot of moving parts and heavy/bulky. If it turns out to be cheap enough and you have the space for it, great. But it has a few inherent disadvantages to deal with.
        EVnerdGene
        • 1 Year Ago
        @Dave D
        Rube Goldberg CVT = also needing a clutch, electronic control, solenoids?, , , another differential = driveshafts, CVjoints, , , , I think I'll stick with electric hybrid.
          EVnerdGene
          • 1 Year Ago
          @EVnerdGene
          If so efficient, wouldn't need battery cooling systems. Also don't forget you've got an efficiency of charge, and an efficiency of discharge; and some energy loss while sitting at the airport. Yeah, you can't compare with ICE stuff. Like comparing Miller Lite with Chateauneuf du Pape. Butt you've got to admit, current batts are way too heavy, way too big, and way way way too expensive.
      Andrew Richard Rose
      • 1 Year Ago
      looks so complicated to me , more time spent in the shop servicing !
      EVnerdGene
      • 1 Year Ago
      q'Tzal Yeah, electro-chemical-electro efficiency is pretty bad; but I'd imagine a CVT with ~30:1 variator is even worse (just a guess -- 2000 to 60000 rpm ?). Batteries lose their charge - days to months depending on the type. That's one of the major challenges with capacitors; like you said, they're more like flywheels. Long-term, I'm betting on super-capacitors. But so far, I haven't seen a promising place to place my bet. Will eventually obsolete electro-chemical storage.
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