9 replies to this topic

[More&Faster]

i can't figure this out. this is what i know.

users:
renault
mclaren
ferrari


non-users:
brawn

also, are they all using electrical systems, or did some wind up using mechanical ones? example: http://www.autoblogg...-kers-for-2009/

halp

[DocGolem]

Everyone but Williams so far are using/developing electrical based KERS.

Toyota say that they have a system, but they can't see any real benefit from it in terms of lap times. Most of the other teams have the same problem.

[Nacho]

I really want Williams' system to come out and be the shit, as it's the only one that's really innovative.

[DrDickAction]

I really want Williams' system to come out and be the shit, as it's the only one that's really innovative.

dawt

I'm no ecologist, but I think a flywheel is a lot friendlier to a landfill than lead acid/nicad/alien blood or whatever they're using in those batteries.

[Dr. Jimmmah!]

dawt

I'm no ecologist, but I think a flywheel is a lot friendlier to a landfill than lead acid/nicad/alien blood or whatever they're using in those batteries.

while i have to commend williams for thinking outside of the box i'm not 100% certain on the effectiveness of a mechanical KERS system. i'm not sure the energy density of a flywheel exactly, but i'd think batteries should have a higher energy density (i'm not confident of the numbers on http://en.wikipedia..../Energy_density, i'll have a look into seeing if i can get any numbers from SAE papers). add onto that the advantage of being able to move the mass around like a ballast (i.e. locating battery in the nosecone a-la Ferrari) and i'm leaning towards the battery approach for KERS.


here are some pros and cons of each method


battery pros:
higher energy density
ability to move mass (battery) around as ballasts

cons:
mechanical complexity = reliability issues
electric cables need to be very thick to carry huge amperage for KERS (weight)
environmental nightmare


flywheel pros:
mechanical simplicity
environmentally safe (good PR)

flywheel cons:
weight is fixed by the engine (unless you want to run some sort of prop shaft, which would be a bit silly)
heavier due to lower energy density



of course i have very limited knowledge of energy densities of flywheels and batteries (though i've dealt with high-density Li-poly batteries, probably very similar to the ones F1 uses) so if anyone else knows more about energy densities of batteries and flywheels feel free to chime in..




EDIT: i guess the flywheel KERS system doesn't require a separate motor, which is where it makes up for the extra weight of a lower energy density in a flywheel. though advanced battery tech based on Li-ion nanowire could easily throw the balance to favor battery KERS if they could make it viable. Flybrid systems makes such a flywheel KERS system, weighing in at 24kg as opposed to roughly 30kg for electrical KERS..


http://www.flybridsy...m/F1System.html
if ferrari can move around at least 10kg of that KERS system in battery weight to where they want then i'm probably thinking that electrical is still a bit more practical.

[tefnut]

the Economist of all things had a good article on KERS
http://www.economist...ory_id=13350762
interesting stuff, and it's well-written as usual too

Tech.view
Boost for Formula One
Mar 20th 2009
From Economist.com

Racing cars borrow a trick from the Toyota Prius

WITH the Formula One season opening in Melbourne next week, people are about to be bombarded once again with rhetoric of how “racing improves the breed”. The idea that motor racing is an incubator for technologies that make passenger cars safer and better has always been something of a myth. With its demand for the ultimate of engineering in terms of performance and lightness (and scant regard for endurance and cost), F1 racing is so far removed from everyday life on the road that there is little scope for transferring its technology from the exotic to the mundane.

Even the oft-quoted example of disc brakes being pioneered by motor sport is not exactly true. They were used on passenger cars made by Lanchester and Crosley in Britain, and Chrysler in America, long before they found their way into the Jaguar C-type that trounced all comers at Le Mans in 1953.

As often as not, the flow of new automotive ideas is the other way round, from road to track. In fact, the biggest innovation being introduced to F1 racing this year comes from the lowly Toyota Prius and its hybrid forebears.

The technology in question is KERS (kinetic energy recovery system) for capturing and storing the car’s braking energy instead of wasting it as heat. The idea is that racing drivers will then be able to use the stored energy to deliver quick bursts of speed for overtaking—and thereby make the sport more entertaining.

Actually, the idea of regenerative braking—slowing a vehicle down by converting some of its kinetic energy into another form for later use—comes originally from locomotive engineering. In electric trains, the braking energy is converted into electricity and fed back into the overhead power supply.

In electric cars and hybrids like the Prius, the electric motor that drives the wheels is likewise made to run backwards as an alternator during braking. But the electricity generated is stored in a battery or a bank of capacitors for later use by the vehicle itself.

This year, the F1 teams will have the option of using KERS. Next year, it will probably be mandatory. For the time being, team managers will choose to use it depending on the type of circuit and the driver’s girth.

That is because the performance gained with KERS comes at a price. At present, regenerative braking adds between 20kg and 30kg to an F1 car’s weight. On certain circuits and with some drivers, the speed gain from KERS can be cancelled out by the additional weight of the system.

Regulations require that an F1 car must not weigh less than 605kg, including the driver and the vehicle’s various fluids. It can weigh more. But no F1 car constructor would build a vehicle one gram more than the minimum for fear of making it uncompetitive.

In practice, constructors build their racing cars much lighter than the regulations require, and then bring them up to the mandatory minimum by adding ballast as low down as possible, and where it will best improve the vehicle’s handling and reduce its tyre wear.

That depends on the driver and the circuit. With less ballast to distribute optimally around the car, a heavier driver is already at a competitive disadvantage. Include KERS and the car could be out of the running altogether, despite having a peak power 10% more than normal. The extra weight could also rob the car of its full fuel load, forcing it to make extra pits stops during a race.

The smart thing about the new regulation, however, is that it is a performance-based standard rather than a functional one. The rule merely says no more than 60 kilowatts of power may be transmitted to or from the car’s back wheels, and only 400 kilojoules of energy can be stored for use each lap.

That is equivalent to having an additional 80 horsepower (the extra 10%) on tap for six seconds or so during each lap. Used judiciously, KERS should offer three-tenths of a second gain per lap—a lot when the difference between coming first or second can be a few hundredths of a second.

The F1 teams have been left to decide individually how best to achieve the burst in power from KERS. Most have elected to use a Prius-like system, with a motor/alternator coupled to a battery. The technology is well understood and a sensible choice for teams in a hurry.

But battery systems are inordinately heavy—the Prius’s weighs 55kg. And making them light enough for racing means cutting safety margins to the bone. Meanwhile, keeping them cool adds further to the complexity and weight.

There have already been two nasty incidents with KERS prototypes. A BMW Sauber mechanic was recently blown off his feet by an electric shock from a car fitted with the device. A week earlier, Red Bull Racing had to evacuate its factory in Britain when a KERS battery exploded. So far, only one constructor (Renault) out of the ten teams competing in Formula One this year has elected to use KERS at Melbourne.

However, the electrical version of KERS is not the only—nor possibly the best—way to capture kinetic energy during braking and use it to boost power. Your correspondent has long been a fan of flywheel storage systems. Primitive flywheel-powered buses appeared in petrol-strapped wartime Europe. But it was not until the 1970s, when the nuclear industry started using centrifuges spinning at speeds up to half a million revolutions a minute to enrich uranium commercially, that most of the mechanical problems were solved.

Carbon-fibre belts prevented the rapidly spinning parts from flying apart under their own centrifugal force. Magnetic bearings solved the friction problem. All that was needed to make a mechanical energy-storage system was a good enough rotational seal, so the flywheel could spin freely inside a vacuum chamber with no air resistance.

By all accounts, the sealing problem has now been licked as well. At least two companies have developed flywheel-based regenerative-braking systems for cars.

The carbon-fibre flywheel in the KERS produced in Britain by Flybrid Systems , in conjunction with transmission specialists Xtrac and Torotrak, spins at 60,000 revolutions a minute. The other flywheel system, developed by Automotive Hybrid Power, also in Britain, for the Williams F1 team, runs at 100,000 revolutions a minute.

The key is to make the flywheel as light as possible and to encase it in a vacuum chamber. With little inertia, friction or drag, the wheel can be spun up to speed in a trice, and then made to dump its rotational energy back into the car’s transmission in seconds. Both mechanical systems are said to be lighter and faster than their electrical equivalents.

As carmakers downsize their engines to meet tougher fuel economy and pollution standards, driveability and overtaking performance is beginning to suffer. Something like KERS is going to be needed in road cars to boost their torque temporarily for climbing hills and overtaking safely.

An instance, then, where race-bred systems find their way into family cars? Your correspondent would be delighted if they did. But he suspects Jaguar and BMW will be selling passenger models equipped with KERS long before Formula One has made its power-boosting technology a decisive factor in winning races.

[Nacho]

if ferrari can move around at least 10kg of that KERS system in battery weight to where they want then i'm probably thinking that electrical is still a bit more practical.

Seems Ferrari's KERS is still mostly in the floor of the center.

http://www.formula1....09/806/638.html

Although battery might be more practical right now I think the flywheel has more potential as a total system. Although I don't particularly want to sit on anything that's spinning at 100,000 RPM, personally.

edit: seems Honda had (has?) a similar flywheel KERS system that they actually tested, to decent results.

While Honda had developed a flywheel solution in cooperation with Flybrid, Brawn GP does not have plans to run it in the BGP 001. The solution was however track-tested and is reported to be an all-mechanic solution fixed on the frontal side of the engine.

http://www.f1technic...t/f1db/cars/956

[More&Faster]

i've read some things about flywheel systems for my senior project and it seems the bigger and better they are, the more energy absorbing material they need around them in case they explode. this is what really kills them. without that, they could attain very high energy densities.

i prefer the idea of flywheels because it seems to me it COULD be more energy efficient since there's no conversion to and from electrical power, but under the current rules energy efficiency is completely unimportant since you can only use 7 seconds or so of power. the only thing that matters is making the thing as light as possible.

i'm undecided on which system is more dangerous

[More&Faster]

thanks for all the info guys

[chiuey]

i can't figure this out. this is what i know.

users:
renault
mclaren
ferrari


non-users:
brawn

also, are they all using electrical systems, or did some wind up using mechanical ones? example: http://www.autoblogg...-kers-for-2009/

halp

quick nick is using it too, but not cubical, coz he's too heavy