F1 Powerunit

Nishant Raj

F1 Powerunit Explained

Formula 1 is the pinnacle of motorsport engineering and over the past few years, it has seen lots of changes particularly with the introduction of hybrid technology. So, from 2014 onwards the engine is not referred to as a single entity, instead the word “power unit” is used. So, do you know what comprises a power-unit? Let’s find out!!!

Basic Architecture:

F1 Powerunit

Powerunit Components:

As would be expected an internal combustion(I.C) engine forms one of the major components, currently, the rules mandate the usage of 1.6 litre turbocharged V6 engines with rpm limit of 15,000.

This new engine is considerably downsized when you compare with 2.6 Litre naturally aspirated V8’s which were in use before 2014.

So, as would be obvious the power generated by the new engines is less that is around 600 bhp when compared to around 800 bhp of V8’s.

Now, the question is how do they make up for this loss? Here comes the role of the turbocharger and the energy recovery system.

Turbocharger: Before you read further on it’s of paramount importance that you know what a turbocharger is. So, you can check this out:

2014 saw the return of the turbochargers which were not used in F1 since the Turbo era, these new Turbo’s though are very different from those used in the Turbo era, these being highly efficient. How?

As in a normal road car with a turbocharger, the exhaust gases spin the turbine resulting in intake of air which is then fed to the engine cylinder resulting in more combustion and thus more power. So, what’s new? Let’s see.

The turbocharger is directly connected to Motor Generator Unit-H (MGU-H) via a mechanical shaft.So, as the exhaust gases spin the turbine, there is simultaneous rotation of the mechanical shaft as it is connected to the turbine. This mechanical energy is converted to electrical energy in MGU-H and is then stored in the battery.

With turbocharger’s, there’s always the problem of turbo lag. F1 engineers have come out with a very clever system to prevent this turbo lag.

As the driver goes off-throttle, the flow of exhaust gases decrease and this causes the turbine of turbocharger to spin slowly, so to overcome this problem the energy stored in the battery is transported back to MGU-H which converts this electrical energy into mechanical energy and this causes mechanical rotation of the shaft which is linked to the turbine, thus preventing turbo lag.

F1 Powerunit

Essentially, what’s happening is the reverse, that is instead of electrical energy, mechanical energy is generated by the use of electrical energy stored in the battery.

So, from this, we can conclude that motor acts both ways. But, with the use of turbocharger, there is the requirement of an intercooler which takes up lot’s of space and this puts considerable strain on the aerodynamic packaging of the car.

Energy Recovery System:

Current generation of F1 power units has ERS which is somewhat similar to KERS which was introduced in 2009.

While the KERS gave a boost of around 80-90 bhp, the ERS gives a boost of 160 bhp for around 33 seconds per lap. So, its clear that the new energy recovery system is more efficient than the KERS.

Do you know why? Here’s the fun part!!!

Energy recovery system mainly consists of:

    1. Motor generator units: MGU-K(kinetic) and MGU-H(Heat)
    2. Battery

The MGU-H is connected to the turbocharger while the MGU-K is connected to the crankshaft of the engine.(If you don’t know what is crankshaft and working of an I.C engine then check this out: ) The other end of both MGU-H and MGU-K is connected to a battery.

F1 Powerunit

So, the power generated by I.C engine is transferred by the crankshaft to thegearbox,driveshaft,differential and finally to the wheels. This is the basic process which happens even in your road car.

Now, the as the engine generates power there is rotation of the crankshaft and this causes rotation of the mechanical shaft leading to MGU-K and like in MGU-H there is generation of electrical energy which is stored in the battery.

Now, what happens when the driver presses the Boost button? As the button is pressed the energy stored in the battery is transferred to MGU-K.

The MGU-K converts electrical energy to mechanical energy and this is transmitted to the crankshaft which now rotates at a faster speed which eventually get’s transmitted to the wheels by the chain of transmission.

Interaction of the components:

1. The I.C engine is started by the starter motor.(external device)

2. Power generated by I.C engine transmitted to the crankshaft and then via the chain of transmission to the wheels.

3. The driver exits the pits and starts a lap.

4. The exhaust gases spin the turbine of turbo, leading to the intake of more air which is then fed to engine cylinder for more combustion.

5. Rotation of turbine also leads to rotation of mechanical shaft connected to MGU-H, this leads to the generation of electrical energy which subsequently get’s stored in the battery.

6. Driver brakes for a corner, instead of Kinetic energy going through the crankshaft to the wheels, the energy is channelled to rotate the MGU-K which is also connected to the crankshaft. This slows down the car and leads to the generation of electrical energy by MGU-K which again get’s stored in a battery.

7. Also, as the driver brakes the flow of exhaust gases to the turbine of turbo decreases, the ECU(Electronic control unit) senses it, and causes the flow of energy from the battery back to MGU-H generating mechanical energy which rotates the shaft linked to the turbine thus causing rotation of turbine preventing turbo lag.

8. The driver exits the corner and goes on to a straight, needs more boost so he presses the boost button, the electrical energy stored in the battery is transmitted to MGU-K which converts this into mechanical energy causing more rotation of the crankshaft and thus leads to the generation of more power.

So, in a nutshell, you can consider the ERS as a triangle.

F1 Powerunit