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Published on August 4th, 2014 | by Jo Borrás

F1’s Hybrid Tech Gives City Bus 20% More MPG

August 4th, 2014 by  

Originally published on GAS2

A new flywheel KERS system similar to those developed by Williams’ Formula 1 team and used in the dominant Porsche/Audi endurance race teams is making its way to city buses – and it could mean a 20% improvement in fuel economy!

In April of this year, Williams sold the technology (and the team that developed it) to British automotive and aerospace conglomerate GKN. In the time since, the copmany has grown to a 55-man operation taht’s working to get the Williams/GKN Hybrid Power system onto the mass market, so that English bus drivers can enjoy the added performance and efficiency that top-flight racing drivers have been enjoying for years.

What makes the flywheel hybrid system different from the systems used in the Prius, for example, is that it works completely without a battery. When the driver hits the brakes, a traction motor on the axle transfers the momentum of the vehicle to the flywheel, making it spin. The spinning flywheel then generates electricity while slowing the vehicle, augmenting the performance of the brakes and reducing wear. The flywheel operates in a vacuum to reduce friction, and can spin up to 36,000RPM. Once the driver gets on the gas, the system applies the momentum built up in the rapidly spinning flywheel to send as much as 120 kilowatts back the axles, helping acceleration and reducing the load demands on the internal combustion engine.

According to the video, above, GKN foresees the technology finding use in a variety of industrial applications, from elevators and commuter trains to (obviously) city buses. We’ll keep you posted on their progress in the weeks and months to come.


GKN Hybrid Power Gyrodrive – Flywheel Hybrid

flywheel hybrid mechanism

Source | Images: GKN, via Wired.

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About the Author

I've been involved in motorsports and tuning since 1997, and write for a number of blogs in the Important Media network. You can find me on Twitter, Skype (jo.borras) or Google+.

  • Matt

    There are apps where this will fit in with batteries. The large mass wanting to stop fast. So you want to put a lat of charge in a very short time.

  • No way

    Or you just go all electric straight away which is much cheaper in total cost than your regular diesel buses, with or without flywheels, and gives you an unlimited mpg since it doesn’t burn any petrol/gas/diesel in the bus at all.

    • Bob_Wallace

      It’s interesting seeing the amount of effort that is going into ICE efficiency now that electric vehicles are a reality. The increased efficiency may slow the growth of electric sales somewhat, but only until purchase prices drop to the point at which the game is won.

      In the meantime these ICE efficiencies are cutting petroleum use and lowering CO2 emissions. It ain’t all bad….

      • No way

        For buses the price race is already won, yet not every new bus is electric. It’s irresponsible of the municipals and bus companies to not go with the lowest cost option, especially when no local emissions, low noise levels and a better driver experience come as added bonus.

        For cars and trucks the increased ICE efficiency is great though, production capacity and price has a long way to go there until EV’s have the whole market.

        • Bob_Wallace

          You know it. I know it.

          I bet most bus company financial offices have no clue. It takes a little while for knowledge of a new technology to be widely known.

          Plus moving too fast into a new technology is a easier way to lose ones job than moving too slow. If you move fast and there’s a major problem, you’ve got a major problem. If you move too slow you’ll probably get a memo to speed things up.

          Let BYD prove itself on US bus routes for a couple more years and then we’ll likely see exponential growth. When there are “homeland” numbers for cost, operation and maintenance believers will be made.

          • JamesWimberley

            There must be a lot of bus operators teetering on the brink and comparing goosebumps. BYD have trialled busses successfully in dozens of cities, yet still the only serious orders ((>100) are in China. Oh, and one 700-bus order in Israel.

      • A KERS flywheel to collect energy lost from breaking by storing rotational motion, may fit nicely with electric cars and buses. It works great during acceleration, which is when battery draining occurs the most. There would have to be fine tuning and such to dovetail the two. Probably a thought exercise of mine more than reality. But, energy type to energy type transfer (kinetic-heat-electrical) is loses energy, unless the system is ideal.


        • Bob_Wallace

          If it stores electricity significantly more efficiently than regenerative braking when slowing. Otherwise it’s just added expense and weight.

          • Offgridman

            That is the good question of how it compares to the regenerative braking. For myself living in a mountainous area it would be great to have this in personal vehicles whether electric or gas. Spend my time driving constantly going up and down hills, and while this mostly talks about stop and go it would be great for all those times when using the brake to not go to far over the speed limit and then the gas to get over the next hill without falling to far below it.

          • Bob_Wallace

            “constantly going up and down hills”

            Not me. When I go shopping I go down a mountain. Coming home I go up a mountain. None of this indecisive up and down and up and down stuff….
            (You’re in East Tennessee?)

          • Offgridman

            “East Tennessee?” That’s right but about as far south as you can do it and still call it Tennessee. The North Carolina border is one mile to the east, and the Georgia border a mile and a half to the south. Technically part of the Blue Ridge or Smoky mountains area but the countryside reminds me of where I grew up in the finger lakes of upstate NY without the crazy snowfalls that came off of the great lakes. In reality I live in the South with just enough elevation to keep the weather reasonable, been loving the past couple of weeks with the nights getting down in the fifties, it’s like early fall is already here.
            If I remember right you are out in the West right? The mountains here in the east have been getting worn down for a lot longer and in most cases are rounded rather than pointed like out there.

          • Bob_Wallace

            Far northern California. About 60 miles south of the Oregon boarder and about 30 miles in from the surf.

            Grew up in East Tennessee, just north of Knoxville (now part of K-ville). Spent a fair amount of time in the Smokies.

            Our coastal mountain are a lot newer. And a lot crumblier. Roads falling off or stuff falling on our roads is a constant, rate picks up when rocks get lubricated by rain.

          • Offgridman

            Okay, you are even further west than I realized, but am very familiar with where you grew up. Job had me east of Knoxville for almost three years Gatlinburg and Pigeon Forge twenty five years ago which is when I decided it was Tennessee for my retirement. But the wife being from North Georgia couldn’t get her to go that far from family so we compromised on here. No complaints really, last time we visited Gatlinburg a few years ago the whole flavor of the area has changed it is so thick with tourists and time shares.

          • Bob_Wallace

            Worked one summer in Gatlinburg and went to school for a couple of years in Maryville. You think Gatlinburg has changed in the last 25. Should have seen it 50 years ago. ;o)

            Beautiful area but I don’t care for the bugs, humidity and politics.

          • Offgridman

            Actually I think I can imagine Gatlinburg fifty years ago as I grew up in a little town that was the county seat that had one stoplight that got turned off at 6 pm..
            At least when I was in Gatlinburg it would still shut down for the winter except for light ski tourism. But with the convention centers and chain hotels it has really changed a lot in the past twenty five.
            Never had much chance to get involved in local politics back then as the company would usually only leave me in one place for a year maybe two. Gatlinburg / Pigeon Forge was unusual for how long. Did hear the stories about the families in control of that area though, it was probably their desire for the big money that has caused the change through the years.

          • Bob_Wallace

            Better highways. More disposable income. Changed the world.

            Pigeon Forge, when I frequented it, had zero tourist stuff. The big attraction was an old mill pond we used to fish now and then. That was when Dolly was a teenage girl we used to watch on local country music TV shows like the Cas Walker Farm and Home Hour.

          • Offgridman

            What I missed the most is some quiet out at Cades Cove, used to be able to take the bike out there and ride the loop during the winter and not see anybody. The last time it was the first week of February and the train of cars reminded me of the former summer traffic. It must be insane with the number of people during the summer now.

          • Bob_Wallace

            One of the world’s beautiful places. We need to get the world’s population back down to where it was when we were young so that be best places aren’t packed out.

            I went to the Stone Forest in China in the mid 1980s. For the most part one walked through in lines as tightly packed as queues at a US theme park. It’s starting to get that bad in some US places.

          • Offgridman

            You will get no disagreement from me on this. It seems like I have been hearing about the problem of the worlds increasing population since my school days. Compared to the amount of area that we have in the US it isn’t that serious of an issue yet but in the urban and city areas it is becoming obvious what a problem it will be. Hearing about the water issues in the west and southwest make it obvious that this needs to be figured out now, not when we reach the crisis point.
            I think that it really needs to be approached as a cultural and social issue though. We have gone so far beyond the need to go forth and propagate that religions have relied upon to increase their membership. Also the understanding that the society will be willing to help care for the elderly needs to become more common, like in Japan, so we can get past the idea of having enough children to secure our old age.
            It is a very difficult issue to mandate the number of children that people can have like the Chinese model, so we are looking at a total societal change in order for people to do what is the best for everyone.

          • The KERS units going into Volvos aren’t that big and heavy. The wheel is carbon fiber and the system works in almost a vacuum. It spins at about 60,000 rpm so between a vacuum and speed, it doesn’t need the weight.

            From a course on power trains:

            Looks like flywheels have lower specific energy than batteries, but 10 times the specific power. This could dovetail nicely in city stop-start traffic with EVs of all sizes.

          • Bob_Wallace

            That being the case, they could play the role supercapacitors have been expected to play, but haven’t to date.

  • JamesWimberley

    GKN is a large, conservative engineering company. Williams build racing cars that are real challengers in F1 competition. We can take it that this works. The underlying question for vehicles is whether hybrids will win out over pure evs – I assume you don’t need expensive flywheels if you have large batteries. Racing cars don’t have typical usage patterns – they are constantly accelerating or braking hard. When did you last brake hard in your car?

    Notice that GKN are thinking of other uses where batteries may be less suitable than flywheels because the braking energy per unit time is larger: trains and lifts.

  • I’m confused and amazed. The KERS flywheel Volvo is developing stores energy as rotational motion that would be lost to heat from breaking. Then transfers the spinning motion back into forward motion via gearing. This seems to be a whole nother thing. The purpose of a flywheel is to keep energy at one state. Therefore minimizing loss do to energy type to energy type transition. Either way, I’m a big fan of KERS. It’s simple. It’s tried and true. Remember those big ol’ farm tractor flywheels? Same thing, but infinitely less refined compared to KERS.

  • Kevin McKinney

    I was interested to see that Williams Advanced Engineering is also getting into flywheel storage for renewable energy, very much as Beacon Energy has done–albeit Beacon is much farther along the road to commercial deployment. (Since Beacon went private following the Solyndra debacle as part of their bankruptcy, news about them has been very infrequent–though they are not quite the black hole that Kilimanjaro Energy has become.)


    • Kevin McKinney

      Though I see, by coincidence, Beacon Power (sorry, not “Energy”, as I wrote above) just did issue their first PR of 2014, announcing the full deployment of their Pennsylvania facility:


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