An F1 MGU-K, or Motor Generator Unit - Kinetic, is a hybrid system that recovers energy that would otherwise be lost as heat during braking. When the car slows for a corner, the rear wheels and drivetrain are still carrying kinetic energy. The MGU-K converts some of that motion into electrical energy and sends it to the Energy Store.
This matters because recovered energy can later be used to boost acceleration without burning extra fuel.
Key Facts
- Kinetic energy of the car: KE = 1/2 mv^2
- Electrical power during energy transfer: P = E/t
- MGU-K maximum deployment power in modern F1: about 120 kW, or about 160 hp
- MGU-K energy recovery limit: about 2 MJ per lap
- MGU-K deployment energy limit: about 4 MJ per lap
- During braking the MGU-K acts as a generator, and during acceleration it acts as a motor
Vocabulary
- MGU-K
- The Motor Generator Unit - Kinetic is a device connected to the drivetrain that can convert motion into electricity or electricity into driving torque.
- Regenerative braking
- Regenerative braking is a process that slows a vehicle by converting some of its kinetic energy into stored electrical energy.
- Energy Store
- The Energy Store is the high-voltage battery system that stores recovered electrical energy for later deployment.
- Deployment
- Deployment is the use of stored electrical energy by the MGU-K to add motor power to the drivetrain.
- Torque
- Torque is a twisting force that can rotate a shaft, axle, or wheel.
Common Mistakes to Avoid
- Thinking the MGU-K creates free energy, which is wrong because it only converts energy from braking that the car already had as kinetic energy.
- Forgetting that recovery happens mainly during braking, which is wrong because the MGU-K needs a speed reduction and generator load to capture useful energy.
- Confusing power with energy, which is wrong because power is the rate of energy transfer while energy is the total amount stored or used.
- Assuming the MGU-K always adds power to the wheels, which is wrong because it can switch between generator mode during braking and motor mode during acceleration.
Practice Questions
- 1 An MGU-K deploys 120 kW for 10 s on a straight. How much energy does it use in joules and in megajoules?
- 2 A 798 kg F1 car slows from 80 m/s to 50 m/s before a corner. How much kinetic energy is removed from the car during braking?
- 3 Explain why using the MGU-K during braking can improve efficiency but still cannot recover all of the car's lost kinetic energy.