By Kritish Elangovan

Decades before, when the first cars were made, they could barely overtake a running cat. As time passed, the shift from steam powered engines to internal combustion engines made rides better. People wanted faster cars, and huge displacements paved the way. The advent of turbos and superchargers proved themselves, as ‘replacement for displacement’. The next major thing on engine technology was the fancy VTEC, which gave you the best performance and equally pleasing fuel efficiency. The future holds more, but it all begins now.

Koenigsegg, the classic rival of Bugatti has come up with the Koenigsegg Gemera. Gone are the times when Koenigsegg was chasing speed records. The Gemera was built for a totally different purpose – ‘Taking your family in a hyper car’. But, that doesn’t mean this car is slow.

The Swedish hypercar maker, had been well known for crushing Bugatti’s world record in 2017. Since then, the brand had come with incredibly fast machines, with some trailblazing technical innovations. With the Gemera, being the latest addition to their lineup, the brand had caught everybody’s attention, thanks to their smart, unique engineering. These are so immense that they can’t be covered in a single blog and hence, the focus of this post is on the powertrain and drivetrain of Koenigsegg’s ‘first car for four’ – the Gemera.

Gear up; this is quite long for a blog, but I assure you won’t regret reading this. And by the end of this, you can proudly tell your mum that you learnt some bleeding edge engineering stuff!

Powertrain

The powertrain of the Gemera is highly sophisticated in terms of technology, as well as working principles. This powertrain outputs a peak power of 1700 hP and 3500 Nm of torque! This is a hybrid powertrain, meaning that it is a combination of an internal combustion engine and electric motors.

The system consists of 2 electric motors in the rear, each capable of 500 hP and 1000Nm of torque, which supply power to the rear wheels, independent of each other, paving the way for torque vectoring. Sitting between the motors, is a lovely internal combustion engine, which Koenigsegg calls ‘The Tiny Friendly Giant’. This engine produces a peak power of 600 hP and an equally impressive 600 Nm of torque. Mounted on the crank of this engine, is another electric motor, capable of 400 hP and 500 Nm of torque. The combustion engine and the third, smaller motor send power exclusively to the front wheels, through a torque tube made of carbon fiber. This power then passes through a torque converter, and is shared between both the wheels via a ring & pinion setup. On either side of the ring & pinion setup, are wet multi-plate clutches. So, either of the front axle can be completely locked independent of the other. So, again, torque vectoring. A 15 kWh, 800 V battery pack feeds electrons to the electric motors, which can propel the Gemera for 50 kilometres, solely on electricity. The battery can be charged using the engine, regenerative braking and by plugging the car to an electric source. The total combined range of this hybrid powertrain is very impressive at 1000 kilometres.

On adding all the outputs from the engine and batteries, we get [(500*2)+600+400] = 2000 hP. However, the motors and the engine reach their peak power at different RPMs and there is a restriction on the amount of power the battery pack can supply. So, the usable power drops to 1700 hP, which is still a great number.

The Tiny Friendly Giant

That’s quite a long name, which is why this engine will be referred as TFG further in the blog. This, is a 2.0 L inline engine with 3 cylinders. But, the most striking feature is its power output. It makes a total of 600 hP, almost 200 hP per cylinder. By far, this is the world’s most powerful 2.0 L engine and also the most powerful 3 cylinder engine. There are various interesting and complicated factors that work in tandem to make this amazing masterpiece work.

CYLINDERS AND PISTON MOVEMENT

First of all, as far as the specs go, this is an engine with 3 cylinders arranged one after the other, with a total displacement of 2.0 litres. The cylinders are, as a matter of fact, larger than the ones in Koenigsegg’s 5.0 L V8. Here’s the math:

• The TFG: 2000 cc / 3 cyl = 666.67 cc/cyl. This means that each cylinder among the three has a displacement of 666.67 cc.
• Koenigsegg’s V8: 5000 cc / 8 cyl = 625 cc/cyl. This means that each cylinder among the eight has a displacement of 625 cc.

So, the individual cylinders in the TFG are larger than those in Koenigsegg’s 5.0 L V8, the one used in Jesko. Some engines make power by revving high; some make power by using boost. The TFG does both. This engine has 29 PSI of boost pressure and revs upto 8500 RPM!

Moreover, the stroke of the cylinder, being 93.5 mm, when compared against the maximum rev range of 8500 RPM, means that the pistons of the TFG move very fast, comparable to the ones in F1 engines.

FREEVALVE SYSTEM

This, is a revolutionary system, which is incorporated in the Gemera. In traditional cars, the inlet and exhaust valves are opened and closed using a camshaft. The camshaft contains avocado shaped structures, which bump into coils when the camshaft rotates. These bumps force the valves to open and close.

On observing the above GIF, it can be inferred that the valves open to a maximum extent, at a point of time, and at other times, the valve is not opened to its maximum. This, is simply due to the shape of the cam. So, if a graph is plotted depicting the extent of the valves opening and closing, it would be something like this:

The ‘Freevalve’ system replaces the camshaft. Instead, an actuator is used, which uses energy from various sources – Koenigsegg calls it the ‘electro-hydraulic-pneumatic’ system. Consider a single inlet valve. The top portion of the valve is fabricated like a piston. Over this piston-like arrangement, is a reservoir of air. Pressurized air comes into this reservoir from an inlet pipe, controlled by an electronic signal. This pressurized air forces the piston to move downwards, and opens the valve. Once the valves had been opened, in order to close them, there is a pneumatic spring system, which forces the piston back, in the reverse direction, thereby closing the valve. This is how the valves open and close in the Freevalve system. The arrival and exit of pressurized air to and from the reservoir is governed by an electronic control module. This system, is light years into the future! The TFG reaches the redline at 8500 RPM. Each of the inlet and exhaust valves must open and close 4250 times per minute. Now, imagine the above defined process taking place 4250 times in 60 seconds, and that too, the throttle response is also being collected and every manipulation is done in milliseconds, to make the engine work at its best.

On the walls of the air reservoir, is a small plate, whose position can be varied using hydraulics. This plate restricts downward motion of the piston. Due to it’s variable position, the extent to which the valves open and close can be altered using this plate.

 

I’m not sure about the exact working of the system. But given the facts, it should follow something similar to the above principle.

Okay, now why does Koenigsegg use this?

• The extent to which the valves open can be altered. At low speeds, the valves open just a little, and otherwise for higher speeds.
• In a traditional camshaft, the valves allow for maximum air flow only at a point of time; the remaining time is wasted in reaching the point. However, in the Freevalve system, air pressure instantly forces the valves to open to their maximum.
• The duration for which the valves remain open can be controlled. So, the valves can remain in their maximum position for a longer duration of time, thereby improving the density of air inside the cylinder, therefore, more power. The valves open for shorter duration at low speeds, and otherwise at higher speeds.
• Variable valve timing is achieved. The valves can be opened only if desired, using an electronic signal. In the case of camshaft driven valves, the valves must open once per RPM of the camshaft, due to its shape. But here, pressurized air does the job and it can be called only when necessary. So, less wastage and more efficient combustion.
• Due to its ability to control every aspect related to the movement of the valves, this system is exceedingly versatile.

Even though the freevalve system has implications of its own, such as high cost and complexity, this will be the future of internal combustion engines.

If the extent of opening of valves is compared to that of a camshaft controlled valves, the graph would look like this.

All these mechanisms, as already quoted, are managed by an electronic control module. It acquires various inputs such as engine RPM, throttle response, etc., and controls the movement of the valves accordingly. This system greatly increases the combustion efficiency, much beyond the regular engines.

In the TFG, each cylinder has 2 inlet and 2 exhaust valves. When the car is running at lower speeds, only one set of the inlet and exhaust valves are used. As the speed increases, the second set of valves also start functioning, yielding never-before fuel efficiency. Koenigsegg claims the TFG consumes 15 – 20% lesser fuel than typical cam engines. The efficiency of the TFG explains itself with an amazing 300 hP per litre. This, value, it’s staggeringly high. This much of an efficient engine is decades into the future. In addition to this, this engine can run on bio fuel, high octane fuel, as well as regular petrol.

The complete engine package, including the oil sumps, weighs just 70 kilograms. This compact design helps the engine to be mounted on a smaller space and yields an exceptionally high power to weight ratio. This freevalve technology relieves the engine off the camshaft, the connecting rods, timing chain, timing gear and many other components. This reduces the total moving mass of the engine, reducing the engine vibrations and also reduces inertia when the engine is working, thereby improving handling.

TWIN TURBO SETUP

Yes, a twin turbo arrangement for a 3 cylinder engine. But the way Koenigsegg has split up the feed for the turbo is quite smart. As already quoted, each cylinder has 2 exhaust outlets. The exhaust through one outlet from each cylinder is feeded to a turbo and the remaining exhaust arising out of the remaining outlets are supplied to the other turbo. At lower RPMs, only one exhaust valve opens and only one turbo functions. However, as the speed increases, as the other set of valves open, both the turbos work simultaneously.

These two are the main factors, that power the TFG to 600 hP. To put things into perspective, the Lamborghini Huracan makes 602 hP from a 5.2 L V10 engine! This explains the immense efficiency of the TFG.

Drivetrain

What’s the use of so much power, if it doesn’t make it to the ground? Here’s where things get more hefty. This car, the Gemera, has just a single gear. It has no gearbox, no neutral, no controllable clutches. So, how does a car with just a single gear have an incredible 0 to 100 km/h time of 1.9 seconds, while managing a top speed of 400 km/h?

It’s an established fact that, if you increase the torque, the power reduces and vice versa. So, in conventional cars, if you want a better acceleration, it takes a toll on top speed and if you need a higher top speed, you can’t expect great acceleration. But, this isn’t the case in the Gemera. Traditional cars use gearboxes, with 6, 8 and even 10 gears; but not this one. It uses a single gear. Koenigsegg calls this, the ‘Direct Drive’.

KOENIGSEGG DIRECT DRIVE

The Koenigsegg Gemera uses a torque converter. I’ve already written a blog about how a torque converter works. Check it out here.

However, for a simple understanding of how a torque converter works, consider two table fans, A and B, placed one behind the other. This arrangement is in such a way that fan B is right in front of fan A. When the fan A is plugged to an electric source, the blades start rotating and blow air. The air blown by the fan A rotates the blades of the fan B. Note here that the fan B doesn’t have any physical contact with the fan A. Its just the blowing air from A that rotates B. Now, the blades of the fan B can be stopped from rotating, by just using an obstruction; however, the fan A remains blowing air. When the obstruction is removed, the fan B again starts rotating

Imagine this system, more compact and 100 times more efficient, and that’s a torque converter. Now, in a car, the fan A is similar to the crankshaft and like electricity powers the fan, the engine powers the crankshaft. The fan B is equivalent to the driveshaft, which rotates the wheels. However, instead of air, a transmission fluid is used. This fluid gets sprayed towards the driveshaft, when the crankshaft spins. The force this fluid exerts when it is forced towards the driveshaft rotates it. When the brakes are applied, the driveshaft stops rotating, just like the fan B stops rotating when an obstruction is used. When the throttle is applied, the driveshaft again starts moving, just like the way in our example with the fans. This is how the car comes to a stop without killing the engine. Now, the fan A, is technically called an impeller and the fan B, is a turbine. In addition to this, there is a stator, between the impeller and turbine. The stator has blades on it, at steep angles. So, when the transmission fluid passes through the blades of the stator, the speed with which the fluid is being sprayed increases. This fast-moving fluid moves the turbine even faster. So, theoretically, the speed of the driveshaft is higher than the speed of the crankshaft. This is how torque is multiplied. This, is an extremely oversimplified version of how a torque converter works.

Now, the advantages of using a torque converter is that it reduces the number of gears. This significantly reduces the weight of the drivetrain assembly. Moreover, some amount of power from the engine is wasted as transmission losses, as the power passes through a number of gears before rotating the axle. These losses are minimized(definitely not eliminated) as far as possible, hence supplying maximum torque to the wheels

Koenigsegg claims that the Gemera has 11,000 Nm of wheel torque. Well, here’s the math:

• The TFG and the third electric motor send torque towards the front which has a gear ratio of 2.69:1. Multiplying this with the torque sent to the front wheels, we get [1100 Nm(600 from TFG and 500 from electric motor) * 2.69 = 2959 Nm.

• The electric motors, which power the rear wheels have a similar gearbox with a gear ratio of 3.325:1. Multiplying this with the torque they send to the wheels, we get [2000 Nm(1000 Nm from each motor) * 3.325] = 6650 Nm.

• On adding these, we get (2959+6650) = 9609 Nm of torque. But this is lesser than the torque claimed. Well, the torque converter can multiply the torque by 2.5 times, up to 3000 RPM. This gives a peak of theoretically 7397.5 Nm of torque for the front wheels. However, due to the difference in the RPMs at which this is obtained, it reduces. The final available wheel torque, thus reduces to 11,000 Nm.

The Conclusion

These are just highly simplified versions of how the Gemera actually works. The technical innovations on this car are so immense. By this time, the Gemera should’ve been launched, but due to the COVID-19 pandemic, the 2020 Geneva Auto Show was cancelled and the Gemera made its debut via an online event. Everything about this car is crazily over-engineered. Such innovations had never been witnessed and that’s why Koenigsegg is leading us to the future. Christian von Koenigsegg once quoted, ‘Nobody can do what we are doing’ and that is unreservedly verifiable with what he had achieved with the Gemera.

Well, you just learnt some crazy nerd mechanical stuff. Ping me in the comments, if any doubts should arise; suggestions are also welcome. We have all wondered what makes these cars so expensive, and well, this explains that(lol).