Kinetic Energy Recovery Systems or KERS for short are devices used for converting some of the waste energy from the braking process into more useful types of energy, which can then be used to provide the F1 cars with a power boost.
KERS is based around the fact that energy cannot be created or destroyed, but it can be endlessly converted. When you drive down the road your car has kinetic energy, when you brake that kinetic energy is mostly converted into heat energy.
With KERS, that wasted energy from the car's braking process is stored and then reused to temporarily boost engine power.
Illustration 1 is a CAD image showing one type of recovery device installed on top of the gearbox at the rear end of the car. When the car is braking, this mechanism captures the energy produced by the two rear wheels.
Illustration 2 shows the typical placement of the main components at the base of the fuel tank, and illustrates the system's basic functionality.
In the charging phase during braking kinetic energy from the rear brakes (1) is captured by an electric alternator/motor (2), controlled by a central processing unit CPU (3), which then charges the batteries (4).
When the driver presses a boost button on the steering wheel, the electric alternator/motor, located at the front end of the crankshaft, gives the stored energy back to the engine in a continuous stream. This energy equates to around 80 horsepower and may be used for up to 6.6 seconds per lap.
The location of the main KERS components at the base of the fuel tank reduces fuel capacity by around 15kg, enough to influence race strategy, particularly at circuits where it was previously possible to run just one stop. The system also requires additional radiators to cool the batteries.
The weight of the KERS - about 35 to 40 kilos - raises the centre of gravity of the car by a few centimetres, enough to influence the handling in the corners.
Mechanical KERS, such as the system being developed by Williams, is opposed to the electrical KERS illustrated here It works on the same principle, but use a flywheel to store and re-use the waste energy.
Photos: Ferrari, Magneti Marelli