Kinetic energy recovery system

Figure 1. A kinetic energy recovery system.

Kinetic energy recovery systems (KERS) are systems used in Formula 1 vehicles (ex. a race car) in order to recover kinetic energy for future use. It works by converting the energy of motion when the car decelerates (which would've been lost as heat without a recovery system) into electrical energy which is stored in a battery, supercapacitor, or as mechanical energy in a flywheel. The driver can then press a button on their steering wheel, discharging the battery to motion of the drive shaft and giving their vehicle a boost of power.

KERS uses three main components to do its job:

1. a Motor/Generator Unit (MGU): this converts mechanical energy into electricity and vice versa.
2. Power Control Unit (PCU): controls the switching of electric current between the MGU and the battery.
3. Storage device: which can be any of those mentioned above (battery, supercapacitor, flywheel).

The KERS uses a "charge cycle" and a "boost cycle"—the former occurring upon deceleration in order to store the kinetic energy, and the latter occurring when the driver presses the KERS button.

The battery is allowed to store 400 kilojoules (111 watt-hours) per lap, giving Formula 1 drivers 82 horsepower to use for 6.6 seconds each lap.

The schematic below shows how a kinetic energy recovery system works.

Figure 2 The operation process of KERS in Formula One from

For Further Reading

For further information please see the related pages below:

• Regenerative braking
• Fuel efficiency
• Torque
• Drive train (there's a fun video explaining differentials there)
• Drive shaft
• Or explore a random page