Of the radical changes to the technical regulations being implemented in Formula 1 for 2009, the biggest challenge for teams is the development of Kinetic Energy Recovery Systems (KERS).
The energy-saving devices have hit the headlines for unwelcome reasons over the past week, raising serious questions about both safety and whether the systems will be ready for next season.
So with this in mind, we asked our expert analyst Mark Hughes to demystify the whole KERS concept; and to explain both the challenges that need to be overcome and the likely effects on car performance.
The Kinetic Energy Recovery System (KERS) dominates technical talk in the F1 paddock right now.
Next year’s new regulations allow these devices to be used for the first time. They store energy otherwise lost during braking and convert it into power.
Legislating the devices into the rules is one thing; getting them working effectively and safely is something else. Teams have only just begun testing them and already we have seen two battery fires and a mechanic receiving an electric shock.
How KERS will work
There are expected to be two types of KERS systems in use next year: battery and flywheel.
The battery system seems set to be the more popular method. It harnesses the braking energy by storing it in super-capacitor batteries which then release power to the driven wheels when required.
The flywheel method looks set to be used by Williams (and possibly Honda and/or Toyota). Here the braking energy is used to turn a flywheel and when extra power is needed the wheels are coupled up to the spinning flywheel to give a boost in power.
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 idea is not only to force F1 to develop green technology but also to help overtaking. A chasing driver could deploy his KERS device as he is catching the car ahead to give him an acceleration boost.
Of course the driver being chased can use his KERS device defensively at the same time, thus negating the chasing driver’s power advantage.
But the limited storage of extra energy means that drivers will have to be very tactical in how they deploy the device.
Because it takes time to restore the energy after you’ve used it, it could be that you have used up your supply and the guy behind still has some left as you arrive at the critical point of the track.
In principle it brings an interesting new dimension to F1. But there are a lot of difficulties to overcome first – and it is by no means certain that teams will have their devices ready in time for the beginning of next season.
The use of KERS will not be compulsory, and so several teams are expecting to at least start 2009 without it.
The challenges
Although battery-type KERS devices are used on hybrid road cars such as the Toyota Prius, the technology required for an F1 application will be rather different.
The batteries in a road-going hybrid are expected to last for pretty much the life of the vehicle.
Because this is F1 the batteries here will need to be as small and light as possible for the given level of power, and as such they will be ‘on the edge’ technologically and will probably last only for one race weekend – if that long!
BMW’s Mario Theissen has pointed out that the power-to-weight ratio of the F1 device is three to four times that used in the company’s hybrid road cars.
The safety concerns surround electrical fires with the batteries and the risk of electrocution.
When the cars come into the pit garages still carrying their stored electrical energy, the teams will need equipment that releases this energy from the car into a storage device. Only then will the car be safe to work on.
The implication is that marshal posts will need access to similar equipment in the event of a stranded car on-track.
The matter of exploding batteries is a potential hazard not only for the driver and crew but also for those anywhere near because of the chemicals used in the lithium batteries.
Teams believe they can install the batteries and/or flywheels in such a way that there is no risk of them coming adrift in the event of an accident, but that is something that will need to be incorporated into the standard FIA crash-testing of each design before it is allowed onto the track.
The effects on performance
As yet, the performance gains are not expected to be overwhelming.
The use of an extra 80bhp for just under 7s would nominally gain around 0.3s of lap time, but against that gain needs to be subtracted the effect of the less optimal placing of weight.
The devices, with batteries and associated equipment, will weigh around 35kg.
Teams currently use around 60-70kg of ballast, which they place wherever best suits the dynamics of the car on a given track. But wherever they place it, it is always very low down in order to keep the centre of gravity as low as possible.
With KERS devices using up around half the current ballast, the centre of gravity height will increase and there will be less flexibility in where the weight is situated within the wheelbase.
There are potential issues also with torque effects on the rear axle as the device becomes saturated and cannot accept any more braking energy. The step change on the axle load could make the car unstable under braking.
The current plan is that the power and storage capacity of the devices will be progressively increased over coming seasons, with a jump to 100kw and 800kJ of storage in 2011 and then 200kw and 1,600kJ in 2013 taken from both axles rather than just the rear axle, as configured until then.
But as can be appreciated, there’s an awful lot of work to do yet just getting the first generation of devices safely up and running.