Why KERS has the potential to disrupt the automotive industry
By: Martin George
Tags: Science, Automotive, Automobile, Cars, Technology

In 2009 this unusual drivers aid was introduced to add a bit more excitement to Formula One whilst also ushering in a new “green era” for the sport. Could this gadget help power the school run in years to come?¹

Photo by chuttersnap on Unsplash

For years Formula One has been a proving ground for risky and interesting technologies. Although not as popular with teams since regulation changes, the technology behind KERS (Kinetic Energy Recovery System)has matured to the extent that manufacturers are looking at using it for a wider range of applications.

The technology behind KERS is elegantly simple. A device like an electric motor is mounted on the front axle. Under breaking, these motors change speed with the car and this causes them to act as generators.² The electricty produced is then sent to some sort of energy storage device. This could either be an ultracapacitor, flywheel or even a normal lithum battery. Batteries are less common because of their weight and also difficulties associated with delivering short, intense bursts of energy. When the driver requires the boost, they can push a button on their steering wheel which will send the stored energy back along the same path to the same electric motors that harnessed the energy during breaking. This time these motors can be used to provide additional horsepower to the front wheels for a short period of time.³

It works similarly to if a child was spinning on a roundabout and you threw them the end of a really strong slinky to slow them down instead of you just pulling at the rails. The child will slow down when the slinky gets taught, energy would be stored in the slinky instead of being wasted through any force you exerted. Assuming they held on, the process would eventually be reversed when the slinky was at maximum extension and they would be “boosted” again. The two main differences with KERS are that you have more control over when the energy is released, and the car is propelled forwards not backwards.

In the late 2000s when KERS was first being showcased in Formula One cars engineers were sceptical about applying the technology to consumer vehicles: “I don’t believe there is much in common between KERS and our goals on the road car side. It is very interesting technology, but I don’t believe there is a future for it in road car applications,” said a spokesperson from Mercedes’ road car engine department in 2009.

It goes without saying that people probably don’t need a “boost button” for going to the shops, so if this technology was going to prove useful for road cars then significant modifications would need to be made. For those who do want to get to the shops particularly quickly, Porsche added a flywheel-based KERS system the their 911 GT3 R Hybrid road car in 2010.⁴

Fast forward a few years and the focus has shifted from using KERS for boosting to using it to increase fuel efficiency. Last year, Volvo announced they were planning to make a new fuel saving option available for their popular XC90 SUV. The system was based around a carbon fibre flywheel KERS system which would enable Volvo to offer, “up to 15 per cent fuel savings and emission reductions in real world driving”⁵. It does this by supplementing the petrol engine after harnessing energy from braking, instead of providing additional horsepower on top of the car’s maximum output.

A 15 per cent reduction is not revolutionary on its own. Arguably the most revolutionary part of KERS is the energy storage mechanism that is most commonly used. The use of light materials such as carbon fibre flywheel makes KERS smaller and lighter than a petrol-electric hybrid system and offers almost identical fuel savings⁶.

This is a very good starting point, and with more investment the system could undoubtedly be developed to offer even larger efficiency boosts. The main reason I think this technology could prove revolutionary is because of the exploration into alternative methods of storing energy. A flywheel is essentially a reasonably bulky disk that spins with low friction. Its simplicity means it can last approximately the lifetime of the car under normal use. The ultracapacitors used in other KERS systems have the potential to show similar longevity.

Battery technology hasn’t really changed much in the last few decades — your smartphone is a prime example of this. Comparing this year’s iPhone to the one Steve Jobs unveiled in 2007, the improvements in pretty much every area from the screen to the camera to the processor are astronomical. However, they both use the exact same battery technology, and we’ve all experienced our phone’s battery life getting worse with age. No one wants that in a car.

With the UK government planning to ban the sale of petrol and diesel cars in the next 15 years,⁷ manufactures now have a pretty hard deadline on getting electric vehicles right. KERS will not solve the problem but has the potential to lay the groundwork for technologies that will.