F1’s Energy Recovery System (ERS): What is it?
Formula 1 is said to be the “pinnacle of motorsport”. With powerful engines moving the car faster than 300 km/h, complicated aerodynamics giving the car plenty of downforce (theoretically, F1 cars can drive upside down on a roof of a tunnel!), there’s no denying that these cars are sophisticated.
Fun fact, these fast cars may also be “greener” than street cars. The reason is the thermal efficiency. Modern petrol engines have a 20–35% thermal efficiency, while F1 cars have 45–50% thermal efficiency. One of the reason this is possible is because F1 cars has its own way in converting the normally-wasted heat energy into kinetic energy. How?
Meet the Energy Recovery System (ERS).
Update (April 2, 2021): It’s my only published story here on Medium, but apparently it popped off (especially after the 2021 season started)! I do hope you gain insight in this article. I did a few long overdue editing (adding pictures, rephrasing, adding sentences). I never put a disclaimer here before so let me just say that I am no expert and these information is gained from the internet. With that being said, continue reading!
What’s ERS?
As the name says, ERS is a system embedded inside F1 cars used to recover waste energy coming from the ICE (internal combustion engine). Too fast? Let me explain a little.
A petrol engine works by adding fuel and air into the piston chamber, where tiny explosions would happen. These explosions move the pistons, and the pistons move the crankshaft of the car. The crankshaft connects the pistons to the wheel, thus making the car move.
Now then, we all know that explosions produces heat, in this case in the form of hot air. The molecules of that hot air is so “excited” that it starts to leave the engine in a hurry. Usually, it would come out of the exhaust pipe. All those heat energy is wasted. This is where ERS helps. How exactly does it do the job? I dug some information, and I’ll try to explain it as simple as possible. However, before I explain ERS, I need to explain another part of the car.
As I’ve said earlier, the petrol engine works by adding fuel and air. This means if you want to go faster, you’ll need to burn more fuel and get more air. We can get more fuel into the piston chamber since it’s controllable (like a water tap). However, unless you’re an air-bender, you can’t get more air. This is where turbocharger helps. It’s made of two turbines. The first turbine gets hot air from the ICE, which spins the first turbine. The first turbine is connected to the second one, and the second turbine is spun because the first turbine spun first. While the first turbine spins and exhausts the hot air, the second turbine takes clean air from the outside and transfers it to the ICE. I found this video that explains the turbo concept in a short (and fun l̵i̵k̵e̵ ̵t̵h̵i̵s̵ ̵a̵r̵t̵i̵c̵l̵e̵) way, check it out!
Time to explain how ERS works. There are two main parts of the ERS. One is the MGU-H, the other is MGU-K.
So, what’s MGU-H?
MGU-H stands for Motor Generator Unit Heat. The reason it has “Heat” in its name is because this unit regenerates energy lost from the hot air. The MGU-H is connected to the turbocharger. When the turbocharger spins, the “turbine” inside the MGU-H spins as well, creating electrical energy. The way MGU-H produces electricity is similar to how a generator would, and so it uses the electromagnetic theory, just like a typical generator. The energy obtained by MGU-H can be stored in the energy storage.
Later on, this energy can be transferred to the MGU-K, helping it moving the crankshaft. It can also be used to decrease turbo lag by using the MGU-H as a motor (thus the M in its name) and moving the shaft connecting the MGU-H to the turbocharger. Turbo lag is what usually happens after a braking zone, where the car decelerates and the turbocharger turbines slow down. The turbines slow down because the car produces less hot air (it’s decelerating), and it takes a while to get it back up and running. The motor function of the MGU-H can help move the turbines inside the turbocharger, making it virtually has zero turbo lag (it can just keep spinning in the same speed). That’s how MGU-H converts heat energy into electrical energy, and reusing it as kinetic energy.
Okay, now what’s MGU-K?
MGU-K stands for Motor Generator Unit Kinetic. The reason “Kinetic” is in its name is because it converts kinetic energy into electrical energy. MGU-K usually collects energy when the car is under braking. To understand the way it does its Generator function (collecting energy), it might be better to explain the Motor function first (where it uses the MGU-K energy).
The MGU-K is connected to the crankshaft, just like the ICE. Therefore, the car can move faster when MGU-K energy is deployed. If the MGU-K is broken during the race, the car can theoretically lose 1/6 of the engine power. I like to think the MGU-K as an electric motor, literally moving the car, just like an electric motor in an electric car. The MGU-K uses a similar concept to the MGU-H, spinning its rotor by passing electric current through a magnetic field (it’s electromagnetism again). Because it’s connected to the crankshaft, it moves in the same direction as the crankshaft. This system would convert electrical energy into kinetic energy.
What happens under braking is interesting. When braking, obviously the MGU-K won’t be using electric current since it’s not trying to move faster. This means that the MGU-K rotor is being moved by the crankshaft, not the other way around like when it was in Motor mode. Now the MGU-K is in Generator mode. When wires are moving in a magnetic field, it creates electrical energy. So now, instead of using electric current and making it pass through magnetic field and moving the crankshaft, it moves the wires through a magnetic field, producing electric energy. This is the basic concept of a generator, in case you forgot. This helps in braking the car since the motion is going in a different direction, but that would be for another discussion. If you’re interested, check out this video to gain a bit deeper and more technical understanding.
Cool, how about using it?
Drivers or teams can choose when to deploy the energy collected (or in a cooler F1 term, harvested). Usually, these cars collect the most energy when under braking (using the MGU-K), hence the reason why teams may want to temporarily stop using energy when approaching a hard-braking corner (like the 1st turn in Monza, Italy). They may also want to reduce the usage of the energy when the car is driving through slow corners (the circuit in Monaco has plenty of it). It’s worth noting that the MGU-K is limited to harvesting 2 Mega Joules per lap, while the MGU-H can harvest unlimited energy. So, even though the MGU-K can bring a huge amount of energy store, the MGU-H is even more important because of its limitless harvesting potential (Leclerc had an upsetting day with the MGU-H in 2019).
The energy would usually be used when chasing another car, or going for an overtake. F1 cars have a feature called Drag Reduction System (DRS), which basically opens the rear wing and reduces drag drastically. The DRS may be used when the car is within one second from the car ahead, which may be something that teams want to push for. When using DRS, they can use less energy while reaching the same speed as if they deploy all the energy without DRS. It’s also common that drivers and teams save the energy for a few laps without losing too much time. This energy may be deployed in the final laps, trying to get one extra championship point for the fastest lap time, or to push the car harder to gain positions (this is a good example).
Verdict
There’s no denying that the motor sport in general burns a lot of fuel, but there’s also no denying that these cars are sophisticated. A part of being sophisticated is having a high thermal efficiency. Through the Energy Recovery System (ERS), these cars can harvest energy from waste energy produced throughout the race. There are two main components, the MGU-H (Motor Generator Unit Heat) and the MGU-K (Motor Generator Unit Kinetic). The MGU-H converts wasted heat energy into electricity, while the MGU-K converts kinetic energy from braking into electricity. These energy are stored in a battery, and when needed, can be deployed to help the car go faster.
It’s necessary to remind you as the reader to do more research if you’re interested. As stated earlier, I collected these information from the internet and they may be wrong or outdated. I might explain it in a wrong way, and for that I apologize. I hope this article helped you gain a new insight in F1, in energy conservation, and a new hope. Who knows what the future holds for street cars. Maybe one day the system in F1 cars will be applied to street cars. Thank you for reading this far, see you another time.
