Hybrid power units have been part of the F1 regulations for 11 years, though it’s fair
to say they had an unceremonious and bumpy start.
In 2009, the cars were allowed a fairly small energy regeneration and deployment system
alongside the combustion engine and this was expanded substantially in 2014 to turn the
cars into fully hybrid machines with a significant amount of their power coming from re-captured
energy. Every car that’s used energy recovery systems
since 2009 has used an electric battery to store the energy otherwise lost in braking.
While this may seem obvious, using a battery for this wasn’t mandatory at all and teams
were free to develop whatever they considered to be the best solution to storing energy.
Williams very nearly changed the whole game when pointed their research and development
in a completely different direction from the start.
This video explains how Williams put all their efforts into designing a revolutionary flywheel
hybrid and how, despite never using it in F1, it can still be considered a success story
and a piece of engineering genius. [AD BREAK]
But before we get into the meat of the video let me quickly thank Skillshare for sponsoring
this video I use Skillshare quite regularly as I grow
and develop my skills in video production. Skill share is an online learning community
with thousands of classes in both creative fields and business-type skills.
You really can achieve a lot just by upgrading your skill set, even if you don’t always
have the money or equipment of a big budget organisation.
For example - maybe your want to get into video making but are daunted by all the expensive
gear. No worries - you can learnt o shoot professional looking videos on your iPhone.
And the skills you learn here can carry forward as you develop.
Skillshare is pretty affordable at less than $10 a month compared to the huge cost of workshops
and classes. But you can try it out for free for two months by following the link in the
description. So you don’t have to take my word for it - get stuck in and try it for
yourself. So check out the link in the video description
and learn something new today. Now - let’s get back to Williams’ flywheel.
Let’s wind up to discovering Williams novel flywheel solution by talking about energy
recovery in general. In fact, let’s start by talking about energy.
The way you power… anything is by transferring energy from one state to another - whichever
form is useful for the situation. For example, a gun converts chemical energy
stored in the gunpowder by starting a reaction that creates heat, sound and kinetic energy
that transfers to the bullet, propelling it down the barrel of the gun at high speed.
The energy was stored chemically and was transformed into a useable kinetic (or moving) energy.
We can store and release energy in lots of ways. For example, we could spend a lot of
mechanical energy lifting a large weight up to a great height.
A lot of the energy spent in lifting the weight is stored in the suspension of the mass at
height - a potential energy. To spend the energy, you simply release the
weight and it accelerates towards to ground, converting that potential energy into kinetic
energy until it transfers that kinetic energy to the ground to create a large crater.
The hybrid power units as we know them today in F1 cars take energy under braking and converts
it into electrical energy to transfer it to a battery where the energy is stored chemically.
And the reverse it true when the energy is deployed from the battery back into powering
the wheels. And by ‘recovering energy under braking’,
what I mean is this: when the wheels are turning, they carry a lot of rotational energy.
To slow the car down, we need to take that rotational energy away from the wheels, reducing
their speed. Normal brakes do that by simply clamping down
on the wheels and using friction to sap the kinetic energy away by converting it into
heat which simply escapes away from the car and is lost.
But an Energy Recovery System instead turns the rotational energy into a different energy
and stores it away, reducing the energy wasted and hugely improving efficiency.
So: energy recovery was allowed in F1 in 2009 but only a small amount was allowed to be
stored and deployed which allowed teams to play with and develop the technology without
the pressure of it being a huge amount of the overall power as it is today.
Cars could only deploy an extra 60 kW (or 80 bhp) of power at the push of a button,
but only for 6 seconds a lap. That’s a total of 400 kJ extra energy, which
is over 30 AA batteries. Nowadays, energy storage is ten times higher
and cars can deploy twice as much power for over 5 times longer per lap.
Under the original KERS rules back in 2009, only four teams even tried running KERS at
all. No one ran it in 2010 but it came back with a vengeance in 2011.
In that time, Williams were furiously working on a flywheel solution to their energy recovery
and deployment. But what does that entail? This would mean that Williams would have no
battery at all in their energy recovery system as they would instead store their energy kinetically.
A flywheel is essentially just a heavy wheel that spins super smoothly on an axle.
You can transfer the spinning rotational energy from the car’s wheels onto the flywheel;
in doing so, you slow the car down and speed the flywheel up.
In effect, the flywheel steals spinning energy from the driving wheels, slowing the car down
which contributes to the braking of the car. The flywheel then just sits there spinning
happily until it’s ready to be used: at which point the reverse happens: the rear
wheels steal energy from the flywheel. The car gains power, and the flywheel slows down.
There are actually many ways to transfer energy from a flywheel to the driveshaft (and ultimately
the rear wheels) and the most common mechanical solution is to use a continuously variable
transmission, or CVT. Unlike a standard transmission, which has
a series of discrete gear ratios, a CVT in effect allows you to smoothly adjust the gear
ratios infinitesimally like magic. It’s not in the scope of this video to explain
some of the ways this is done but an advantage of this system is that everything is linked
mechanically. Mechanical energy in the rotation of the wheels
converts to mechanical energy in the CVT, which converts mechanically to the flywheel
- it’s all just one big kinetic system so you reduce a lot of losses that can happen
converting it to electrical and chemical energy as with a battery.
The disadvantage here is that you are extremely limited in where you can put this system as
it has to be right next to the gearbox. However, Williams didn’t do this either.
In order to save weight and allow them to position the flywheel further up the car,
they developed an electronically driven flywheel. The way this worked was that - instead of
a CVT between the driveshaft and the flywheel, Williams put motor generator units. These
are basically like MGU-Ks you’d find in the other battery-powered KERS cars that convert
the mechanical energy from the wheels into electrical energy.
But instead of taking that electrical energy and using it to charge a battery, they used
it to spin up a flywheel in a very clever way.
What they did was lace the flywheel’s carbon mass with magnetic particulate, turning the
wheel into a permanent magnet. The electrical energy from the MGU would then feel into a
stator in the axle of the flywheel, which (as you’ll know if you watch my MGUK video)
will spin up the flywheel. An electric current in the system induces
rotation in the flywheel. Once the flywheel is charged up with rotational energy, you
can just do the reverse to put power back into the car. The spinning magnetic flywheel
can induce current in the electrics, sending electrical energy back to the MGU, which drives
the rear wheels. It was compact, light weight, relatively easy
to build and could spin at over 50,000 RPM in good conditions. This type of flywheel
also has a high power-density - essentially a very good power-to-weight ratio and could
run and run and run without losing efficiency, unlike batteries which do tend to lose efficiency
over their lifetime. Ultimately though, Williams never used this
flywheel design in their F1 car. This was mostly due to packaging problems as, in 2010,
refuelling was banned which increased the size of the fuel tanks significantly, which
expanded into exactly the area where the flywheel would sit.
But the tech was a real success. Porsche used the system in their 911 GT3R and Audi took
a 1-2 at Le Mans with the Williams flywheel hybrid design.
Though Williams deferred to the standard battery system for F1, they continued to develop their
flywheel technology, selling their systems to road cars, sports cars and fleets of London
buses. Eventually, they packaged up Williams Hybrid Power and sold the venture to huge
engineering firm, GKN. So the flywheel didn’t quite meet the needs
of F1 - for now at least - but we’ve definitely not seen the last of its application.
Will we see flywheel systems compete with batteries in race and road car systems going
forward? Well, it’s important to understand a crucial limitation: flywheels can only store
so much energy and they can’t hold it forever. Unlike a battery, which can store energy without
significant loss for a very long time, a flywheel will eventually slow down and come to a stop.
It only stores energy while it’s spinning at high speed. And a flywheel is limited in
how much energy it can store at all - it can only spin safely and practically so fast,
after all. So, while it’s great at recovering and deploying
energy, it’s not so great at long term, high density energy storage. So it still has
great application for racing or for public transport where the frequent braking and accelerating
is the perfect application for flywheels. Perhaps we will see solutions that involve
a mixture of batteries and flywheels in some vehicles? A hybrid-hybrid, if you will. Maybe.