Kinetic Energy Recovery Systems by Sportsman

Kinetic Energy Recovery Systems - KERS.

 

2011 sees the return of KERS to F1. This article is to explain just what Kinetic energy is and how it is recovered and used in F1 or any vehicle for that matter. Kinetic energy and its use is not something new, it has been utilised by man for centuries. An example, windmills are powered by the kinetic energy in the wind.

    

 
All of the above pictures are examples of kinetic energy.

         

Water wheels and hydro electric power stations are both powered by the kinetic energy provided by water movement. Kinetic energy is quite simply the power of motion. Nothing more complicated than that. Any object that is moving generates kinetic energy.  Be it a car, truck, train, or simply someone running.

 

What is so misrepresented by the F1 press and misunderstood is how that energy is harvested and then reused to power the vehicle.

 

Calculating the kinetic energy of any mass that is moving is a relatively simple equasion.

 

  ·  Step 1

Figure out what object on which you want to calculate the kinetic energy.

·  Step 2

Determine the mass of the object that is in motion. The mass of an object is the measure of how much matter is in an object.

·  Step 3

Determine the velocity of the object that is in motion. The velocity of an object is the speed of that object.

·  Step 4

Multiply the object's velocity to itself in order to obtain the square of the velocity (velocity times velocity).

·  Step 5

 

Kinetic Energy Formula

Multiply the value you calculated in Step 5 (mass) by the value you calculated in Step 4 (velocity). You now have the kinetic energy of the object.

There are various methods of calculating kinetic energy but for this article this is the simplest method.

 

Now, how that energy is harvested and stored? This is what is so badly reported and misunderstood. Kinetic energy is not recovered from the brakes. Indeed the brakes do what they have always done which is convert the kinetic energy into heat which is then dissipated into the atmosphere.

 

The engine plays no part at all in recovering kinetic energy. At the time you are recovering the kinetic energy the engine is doing nothing. It is on a closed throttle and producing no power at all. In fact it is assisting in the braking process by providing additional braking power generated by its compression.

 

 

Try pushing your car in gear. That’s engine braking.

 

The only relationship between braking and harvesting kinetic energy is that at that time you are trying to dissipate kinetic energy and instead of converting it all to heat via the brakes, you could use it to power a generator and produce electricity.

 

When the driver applies the brakes he simply engages a switch, to all intents and purposes exactly the same as the stop light switch on your car. That engages the generator and electricity is generated which is then stored in a power cell. This is actually a battery, but it bears no resemblance to the huge black lead acid battery in your car, or the batteries used in the current range of hybrid vehicles which occupy a great deal space and are also very heavy.

 

The electrical resistance of the generator does provide some braking effect but the remainder is still converted to heat by the traditional braking system.

 

 

 

Initially, the regulations limit the power of the KERS systems to 60kw (around 80 horsepower) and the storage capacity of the energy is 400kJ (kilojoules) per lap. What in effect this means is an extra 80 horsepower available for 6.7s per lap.

 

The system pictured below is the Magnetti Marelli system as fitted to Ferrari.

In 2009 the battery was located below the fuel tank which is not really possible in 2011.

This of course is due to the much larger fuel tanks required for the no refuelling regulations still in place for 2011.

 

To accommodate all of this for 2011 is a major technical challenge to the chassis builders and the systems designers..

Comments

[GordonB]

Great article Sportsman. I love KERS.

Do we know that the same power and storage restrictions are in place for 2011? I don't think KERS will ever take off until they remove the storage amount restrictions at least.

Also, it would be nice to see a diagram of how the MGU fits into the drivetrain.

[flood1]

Hi Gordon, there have been no revisions to the regs that change the original specs for the Kers systems. This is so because the Teams did not want to revise their Kers specifications until the 2013 engine specs are agreed. This makes good sense to me.

However, the regs are one of the probs with implementing Kers. It will never be completly useful until is is unregulated. Only then will true innovation be rewarded.

[Ross]

Any detailed info about the Williams flywheel system?

[flood1]

Hi Ross, the best official info is here

http://www.williamshybridpower.com/

You gotta look around for a bit to find all the data, but it is a pretty interesting read.

We ran a blog on here that included some info and pics on the hybrid flywheel Williams/Posche GTR. That article would be here:

http://www.formula1journal.com/2010/05/the-orange-and-white-740-factory-supported-porsche-911-gt3-r-hybrid-was-leading-the-24-hours-of-nurburgring-with-2215-h.html

Thanks for the question, Ross. We don't have all the answers, but we almost have all the questions.

Flood

[Ross]

Thanks for the response, Flood! I'll check those out. I'd seen a vid of the Williams/Porsche GTR system, but the KERS setup is HUGE. I am wondering how they plan to package that for F1.
I didn't mention it in my first post, but these articles are great. Never saw pictures of the actual KERS components before.

[sportsman]

Hi Ross.The Williams KERS system fitted to the Porsche does look big I agree.But that system had about three times the power both in in terms of output and storage capacity than the FIA regulations allow for F1.
It can be scaled down to suit F1 but Williams have decided that they will not do that as it does not fit their development programme.
2011 Williams will run the standard battery system devoped by themselves and the only component that they will outsource is the battery.
WHT development programme is primarily aimed at the sportscar market, both road and track and also into the road car hybrid market.

[plumbing]

Kinetic energy of a body does not include thermal energy, nor any other form of potential energy such as chemical or nuclear energy, or energy associated with its own deformation or with its position in a gravitational or other field.