Demystifying the MGU-K and MGU-H: The Tech at the Heart of F1 Hybrid Power - 33rd Square (2024)

Formula 1 represents the pinnacle of motorsport technology. And when most people think of F1 innovation, aerodynamics, exotic materials, and ultra-high performance immediately spring to mind. But peek under the bodywork and you’ll discover the clever hybrid systems that really set these cars apart – the MGU-K and MGU-H. In this deep dive, we’ll explore what the ‘M’ and ‘H’ stand for, how these systems work, and the ingenious ways they transform F1 car performance.

MGUs – Turning Wasted Energy into On-Demand Power

The MGU-K and MGU-H are motor-generator units that give F1 cars a huge efficiency advantage by recovering wasted energy flows and using them to boost power.

MGU-K captures kinetic energy generated under braking. Through regen braking, it stores this energy in a battery. It can then reverse and deliver this power directly to the drivetrain for a 120 kW (160 hp) burst of acceleration.

MGU-H harnesses thermal energy from the hot exhaust gases. It uses this to spool up the turbocharger compressor, eliminating lag, and channel excess energy into the battery store.

This regenerative braking and exhaust heat recovery means that over 50% of the chemical energy from the fuel gets used to propel the car. That’s a thermal efficiency unheard of in normal road or even racing engines.

So in simple terms, these technologies turn energy lost through braking and the exhaust into electricity that can be redeployed on demand for cleaner, more efficient power. Let’s look at each of them in more detail.

MGU-K – Kinetic Energy Recovery System

MGU-K stands for Motor Generator Unit – Kinetic. The ‘kinetic’ refers to the fact that this system recovers energy from the motion and deceleration of the car.

How does MGU-K work?

A motor-generator unit is connected to the drivetrain. During braking, it acts as an electric generator, converting the rotation of the wheels into electrical energy that gets stored in a lithium-ion battery pack.

This motor-generator can also work in reverse. On demand, it draws current from the Energy Store battery and drives the crankshaft for a power boost of 120 kW (160 hp).

So it’s a two-way energy transfer system – harvesting kinetic energy and then redeploying it for better performance.

The evolution of KERS in F1

KERS – Kinetic Energy Recovery System first appeared in F1 in 2009. But it could only provide a 60 kW (80 hp) power boost. The MGU-K superseded this from 2014 when the current V6 turbo hybrid powertrains were introduced.

This new system gave double the boost of the original KERS. Combined with the MGU-H, it was a huge leap in hybrid technology that helped usher in a new performance-focused era for F1 power units.

MGU-K in action on track

The MGU-K can be deployed multiple times per lap, making it a key overtaking tool for drivers:

• Power boost on demand – At the press of a button, drivers get an instant 120 kW jolt fed directly into the crankshaft.

• Tactical bursts – These bursts can be timed for long straights or exit of corners to maximize the impact.

• Over 4G of braking force – F1 cars can decelerate at over 4G, producing huge amounts of kinetic energy for the MGU-K to recuperate.

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• 33 seconds of boost per lap – The MGU-K allows 33 seconds of hybrid assistance per lap within the FIA limits.

So while ERS only delivers a fraction of the total power, the instant torque boost it provides is invaluable for outracing competitors on track.

MGU-H – Turbocharger and Heat Recovery System

MGU-H stands for Motor Generator Unit – Heat. As the name indicates, this system harnesses thermal energy from the hot exhaust gases to improve turbocharger response.

How the MGU-H works

The MGU-H is intrinsically tied to the turbocharger. It consists of:

• Turbine – Spun by the exhaust gases to convert heat into rotational force.

• Compressor – Driven by the turbine via a connecting shaft to force pressurized air into the engine.

• Motor-generator – Connected to the same shaft. Harnesses excess rotational energy to generate electricity.

So exhaust heat spins the turbo turbine. The MGU-H converts surplus spinning force into electric power. This gets fed into the battery store.

The generator can also act in reverse as a motor. It uses this electricity to spin the compressor and pre-spool the turbo so there‘s no lag when the driver gets back on the throttle.

Spooling up the Turbo with ERS

Turbo lag was once an inherent weakness of F1 turbocharged engines. But the MGU-H effectively eliminated this problem:

So the MGU-H gives the turbo a power source independent of the engine. This lets it maintain speed and compression so it‘s always ready to deliver its boost.

Heat and rotational forces

There are some clever physics principles behind how the MGU-H achieves this:

• Exhaust gases heat up to over 800°C in the turbo and can spin at over 100,000 rpm.

• Up to 30% of waste heat energy gets converted into rotational kinetic energy.

• The turbine reduces the temperature so energy gets transferred into motion.

• Friction between the spinning shaft and generator produces an electric current.

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So exhaust heat gives the turbo its initial spin. The MGU-H then harnesses rotational forces to keep it spooled. This interplay is managed by the master computer 100 times per second!

Unlocking the Potential of Hybrid Power

The MGU-K and MGU-H are pivotal systems within the overall Energy Recovery System architecture:

ERS Elements Working Together

• MGU-K
• MGU-H
• Battery energy store
• Power electronics to deploy energy

Combined, these hybrid components contribute an extra 160 hp in addition to the 740 hp from the 1.6 liter V6 turbo engine:

This gives drivers an abundance of power on tap – over 1,000 Nm of torque in qualifying trim.

Strategic Deployment

The way ERS power gets deployed also adds great strategic intrigue:

• Drivers have an allowance of 4 MJ of hybrid deployment per lap.

• Strategic harvesting and deployment can give an edge.

• Full ERS gives a perceived acceleration boost of over 1.3G lateral force.

• Driver skill manages complex energy flows throughout a lap.

As Lewis Hamilton describes it:

"You‘re using hybrid power and engine power to their maximum potentials lap after lap. It‘s the most strategically challenging and satisfying driving I‘ve ever experienced."

So mastering the hybrid system intricacies provides a competitive advantage.

The Future of MGUs – Greener Performance

F1 is all about pushing technology frontiers, and the innovation around MGUs is already influencing road car development:

• The thermal efficiency gains are being applied to cleaner combustion engines.

• KERS-type regenerative braking is growing fast, especially in hybrids.

• Better electrification, energy storage and deployment pave the way for higher performance electric sports cars.

As F1 pioneers like Mercedes envision it:

“The learnings from F1 continue to shape our road car technology, especially around electrification and hybrid systems. Those technologies are going to be a huge part of the future.”

The MGU-K and MGU-H illustrate how motorsport can spark innovation that filters down to transform everyday transport. As F1 progresses into new rules cycles, expect the ERS systems to continue to drive the evolution towards greener, more thrilling racing machines.

So while many only see the stylish bodywork, the real magic of a modern F1 car happens under the skin. It’s the MGU-K and MGU-H at the heart of the hybrid system that provide the performance jolt. These pioneering regenerative technologies turn wasted energy into on-demand exhilaration.

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