Print 25 comment(s) - last by Samus.. on Mar 28 at 2:24 AM

Volvo testing a prototype of the KERS system right now

Some exotic race cars have been using a KERS system to store and then release power back to the driver in certain instances as a sort of “boost” function. KERS technology is now starting to come to the street and Volvo has a working prototype using the tech.
However, Volvo isn't using the tech just to improve performance; it is using the tech to improve fuel efficiency. According to the automaker, KERS can reduce fuel consumption as much as 25 percent. In addition to improving fuel economy, Volvo says that the KERS tech can also reduce production costs compared to traditional hybrid systems.

Prototype Volvo S60 with Flybrid KERS system

Volvo has test fitted what it calls a “Flybrid” KERS to the rear axle of a S60 to assist the gas engine that drives the front wheels of the car. It captures kinetic energy typically lost from braking and sends it to the flyweel. 150 watt hours of energy can be captured in only 8 seconds, and the energy can be stored for up to 30 minutes or used immediately.

The KERS system – which spins its flywheel at a maximum of 60,000 rpm in a true vacuum and can deliver 80hp -- can be used to knock 1.5 seconds off the car's 0-60 time or in an economy mode to reduce pollution.
The entire system only weighs about 130 pounds, which makes it much lighter than a traditional electric motor and NiMH/Li-ion battery packs used in hybrid vehicles. For example, the batteries alone used in Volvo's current hybrids weigh 660 pounds. 

Flybrid KERS (Kinetic Recovery System) 

The prototype KERS systems won’t reach production in its current form. A production version of the system will see a similar flywheel and transmission attached to a front wheel drive-based transmission. 

Sources: Autocar, Top Gear

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Interesting tech
By bah12 on 3/26/2014 10:43:51 AM , Rating: 1
I wonder how beefy the casing is, and what danger it poses in an accident. One would assume the flywheel is pretty hefty, and spinning at 60,000 rpm means that is a boat load of kinetic energy that would just love to bust out and wreak some havoc. I'd love to see a video of them testing this to it's breaking point, that should make for a big boom.

RE: Interesting tech
By BarryGoffe on 3/26/2014 12:16:33 PM , Rating: 3
Porsche raced these in their 911RSR racecar for a number of years with no issues. Also, these have been used in Formula 1 for a number of years - and have seen some pretty extreme shunts without a single incident. This is pretty well proven out technology at this point. It hasn't seen much use on the road because the system only offers a few seconds of additional grunt as opposed to battery-based systems. Comparing the weights of these systems is a bit of an apples to oranges comparison. The relative energy storage of these systems is as dissimilar as their weights. For lots of stop-and-go driving around town, however, the flywheel based system is probably pretty well suited.

RE: Interesting tech
By therealnickdanger on 3/26/2014 2:19:48 PM , Rating: 2
They've seen many uses over the years:

RE: Interesting tech
By Alexvrb on 3/26/2014 11:16:31 PM , Rating: 3
I hate it when people bring up racing when discussing reliability in the context of pedestrian vehicles. Racing solutions don't compare to long-term ownership of a stock vehicle. You can make an engine scream and deem it "race reliable" because you only have to rebuild it every so often. There's a reason they sleeve race engines. But the typical well-maintained stock engine should have no problem going over 200K without a rebuild. KERS is no different. Show me a car with a KERS system that has only undergone basic maintenance with 200K miles on it. If you want to be an early adopter, good for you - early adopters of certain unreliable DCTs were very valuable guinea pigs.

Other than that, I agree with you. If it can be made bulletproof I would take this over a conventional gas, gas with start-stop only, and the most basic mild hybrids. But it doesn't compare to a modern full hybrid or PHEV, for multiple reasons.

RE: Interesting tech
By BZDTemp on 3/27/2014 7:27:15 AM , Rating: 2
But it doesn't compare to a modern full hybrid or PHEV, for multiple reasons.

That is some statements you're making. I'd be interested in learning what it is you're thinking of with regards to those multiple reasons.

As for comparing racing to normal life then it is not as clean cut as you make it out to be. Th high stress world of racing does not cover everything, but it is a good way to stress test new tech and that includes testing wear factors.

RE: Interesting tech
By PaFromFL on 3/27/2014 8:40:00 AM , Rating: 2
I wonder how they handle the angular momentum constraint. Over 200k miles, pitch, roll, and yaw might take a toll on bearings.

RE: Interesting tech
By wushuktl on 3/27/2014 7:23:20 AM , Rating: 2
While the regulations allowed it, none of the teams in Formula 1 actually used the flywheel method, they all ended up going with a battery. You can only assume that they felt it was the better solution and compromise of size, weight, eventual power output, quickness in development, etc. The Williams team even developed a flywheel system and then made collaborations with some car manufacturers to put it in real cars but still continued to go with the battery in the races. Even though it sounds good on paper, it makes me think there must be something that is not so good about it.

RE: Interesting tech
By Samus on 3/28/2014 2:24:20 AM , Rating: 2
Flywheel storage is incredibly safe. It's physically impossible for the shaft to just "give out" sending the discs flying. The failure is slow and predictable, always at the bearings. As the bearings wear, the flywheel(s) lack rotational efficiency (they spin slower) and when the bearings finally give out, they don't spin at all.

Most modern flywheel storage systems have liquid/oil cooled bearings for added reliability. Typically the flywheels drive the pump, too, so as the mass spins faster, cooling is increased.

By Mint on 3/26/2014 12:43:05 PM , Rating: 4
That's a 24 kWh pack, i.e. >150 times the energy of this flywheel from 5x the weight.

150 Wh of energy needs less than 1kg of modern batteries to store, and doing it in 8 seconds would still only need 20kg of batteries. A well designed 80hp motor shouldn't weigh more than 20kg (Tesla did 250hp from a 32kg motor in the roadster).

So basically this flywheel system weighs more and stores less energy than a traditional hybrid system. There's a reason nobody else is investing in "Flybrids".

Even Volvo itself is introducing a bunch of PHEV models. It's simply a superior solution to saving gas. I doubt we'll see this system go anywhere.

By FiveTenths on 3/27/2014 8:41:02 AM , Rating: 2
I am not sure of the process you used to come up with the 20kg battery pack, but I feel like you may be over-simplifying a bit here.

Apart from the weight of the battery and e-motor, the battery support (heating,cooling, charge management) and the high voltage wiring need to be taken into account. This is a lot of complexity that doesn't really exist in the flywheel concept and complexity typically adds cost.

Then you have to consider the longevity of the battery, it will be difficult to find a battery that can be completely charged/discharged in 8 seconds and still have an acceptable usable life.

Comparing a flywheel system like this to a plug-in hybrid is missing the point in my opinion, and is really an apples to oranges comparison. PHEV are meant to power the vehicle solely by electric power for miles at a time, the system here is meant to capture the energy wasted during braking and use it to augment the acceleration.

Being able to significantly boost efficiency, over a non-hybrid, with a pure mechanical system that weighs less than a 150 lbs is pretty cool.

By Shadowmaster625 on 3/27/2014 9:44:22 AM , Rating: 2
KERs is far more complex than batteries and wires. There is no way to maintain 60k rpm in a consumer product subject to wildly varying temperatures and shock over time. This is a waste of resources, and will never be viable. It will only be bought as toys for those who got lucky standing underneath a bernanke helicopter drop. No one who actually works for a living is ever going to find this design economical.

By FiveTenths on 3/27/2014 10:18:30 AM , Rating: 2
A few points to clarify here:

KERS, as it is used in the article, is kinetic energy recovery system, it captures the energy of the moving vehicle. KERS is used in all hybrid or pure EV vehicles, not just flywheels.

"Batteries and wires" is a gross over-simplification. This isn't lighting a Christmas light with a 9V battery. All modern batteries need a support system to allow them to survive "wildly varying temperatures and shocks overtime".

Any turbo engine on the market today has a turbine that spins at 10's of thousands of RPM so RPM itself is not an issue. The 60K RPM was peak for the system and is only reached when the vehicle is slowing or accelerating.

What makes you think this is more expensive than a battery? Look at the price of used HEV's, the car is worth less than the cost of a battery replacement. How is that economical?

By Mint on 3/27/2014 11:06:17 AM , Rating: 2
I didn't say it will entirely charge in 8s. I said it will charge 150 Wh. If you put a large enough battery in there then it can do that.

Take a look at A123's 32113 cell, which has been around for a few years now (I'm sure better batteries exist). It weights 205g, and will do 500W charge/discharge for 10s. It's a 15Wh cell that will do over 250kWh of energy throughput before degrading to 80%. Take 100 of these cells, and the pack will be able to take hundreds of thousands of 150Wh microcharges before degrading.

The flywheel isn't cheap and simple either, as you need a CVT and sophisticated control to transfer the energy seamlessly to and from the 0-60k RPM flywheel. Its reliability is a lot less proven than that of batteries, which have been doing hundreds of thousands of cycles in hybrids for over a decade.

Not the only one
By distantman on 3/26/2014 12:56:15 PM , Rating: 2
Garbage truck manufacturers are looking at this type of solution. Given that the bulk of their driving is short acceleration and stopping, this could be a huge deal for their industry.

RE: Not the only one
By Mint on 3/26/2014 7:34:41 PM , Rating: 2
Garbage trucks also have predictable, regular routes with low average speed. That makes them perfect candidates for EV powertrains. The hydraulic pumps could also be powered by electric motors more efficiently and reliably.

My guess, however, is that garbage trucks spend many times more on labor than they do on fuel, so the impetus may not be so great.

RE: Not the only one
By BZDTemp on 3/27/2014 10:21:48 AM , Rating: 2
Money is money, so if a KERS system makes for lower running costs and doesn't cause issues that offset those savings it will come.

Pretty much anything moving that does a lot of start/stop actions should be well suited for KERS, so anything in heavy city traffic is a good place to look.

I know that in the past there has been city buses equipped with kinetic energy recovery systems, but those weren't so successful they stayed in use. I'm guessing that fuel was cheaper back then and I suppose that those systems wasn't electronically controlled as they will be today.

Parts of the city railway system here in Copenhagen that stores and releases kinetic energy to the trains. When the lines was placed they simply placed the train station on hills whenever possible, just small ones a few meters high but it still makes a difference. The trains normally stops at all stations so going up to stations makes for easier braking and exchanges kinetic energy with potential energy, then when the trains start from the stations the process is reversed "automatically".

RE: Not the only one
By Mint on 3/27/2014 4:46:33 PM , Rating: 2
Pretty much anything moving that does a lot of start/stop actions should be well suited for KERS, so anything in heavy city traffic is a good place to look.

And they're also well suited to electrified powertrains.

Garbage trucks are even better suited, because not only do they move at a very slow average speed (thus not needing long range), but they also have a hydraulic system. Every manufacturing company knows that it's more economical and reliable to use an electric motor to drive hydraulic pumps than an ICE, if you have the option.

Lifetime cost is the bottom line, and KERS can only do so much when paired with $4/gal diesel.

By Johnmcl7 on 3/26/2014 11:09:51 AM , Rating: 3
Mazda have implemented a small scale ERS in their new 6 (the European ones anyway, not sure if that model is in the states) that uses a small capacitor that's charged up and then used to power the electrics in the car at times when the engine isn't needed for motion (decelerating, car is stopped etc.)

The economy gains aren't huge (47mpg for the two litre 163bhp petrol engine vs 35mpg for the 2.5 litre 167bhp petrol engine it replaces, both normally aspirated) but the system seems small and reasonably simple allowing it to be fitted to most of the range as standard.

Although diesels can offer better mpg, in the EU at least they're getting increasingly complicated to deal with emissions regulations which in turn hampers their reliability. I've just bought my first petrol for that reason as I've had enough of the DPF and EGR systems even though I was very careful not to use the car for short trips.

By tat tvam asi on 3/26/2014 12:42:36 PM , Rating: 2
Mazda IELOOP has some side benefits too: it reduces wear of brake pads due to regenerative braking (as with a regular hybrid)... it also prolongs the life of the battery.
I would love to see this in a Mazda-2, as it makes more sense to augment a small engine with an an additional energy source like a supercap. I would also love to see this technology become cheaper and ubiquitous.
Unfortunately, EPA ratings currently don't give credit for this (I am told), but real world mileage will definitely be better.

By Alexvrb on 3/26/2014 11:26:06 PM , Rating: 2
EPA ratings are based on manufacturer-reported test results (with spot testing from the EPA which I wish was more aggressive), not "credit". If it really helps so much, it'll show up in testing and thus impact the numbers you see. The fact of the matter is that if you want to have a significant impact on mileage, you'll need a lot more energy capacity from an array of supercaps (or an advanced Li battery) and an electric motor so that they can use the energy they capture to *gasp* turn the wheels.

IELOOP might help a tiny bit more if you drive like a grandma on an empty road, though.

Flywheel blowout
By Torgog on 3/26/2014 11:11:39 AM , Rating: 2
Like other flywheel designs, the wheel itself my have a "self-destruct" component, wherein it safely disintegrates should the vacuum abate or sudden friction becomes apparent. Still, amazing technology.

Here we go again
By flyingpants1 on 3/27/2014 8:41:41 AM , Rating: 2
How can we increase our pathetic MPG numbers (besides straight-up lying about them)?

Let's see, Atkinson cycle, hybrid, engine start/stop, CVT, Skyactiv, and now this?

You guys know it's possible to build a 100mpg car today, right? You know a 92' Civic can get 100mpg, right?

EVs will finally put an end to all this nonsense.

By BZDTemp on 3/27/2014 10:05:13 AM , Rating: 2
There is a good piece about how the car is to drive and all on their website. Worth a look.

Volvo may be on to something.

By HoosierEngineer5 on 3/26/2014 1:10:08 PM , Rating: 1
Perhaps others like to wait until half way through the article to get to the point while the author tells a story, but I for one agree with you.

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