The Electrical Powerhouse of the Mercedes-AMG ONE

The Hybrid System of the Mercedes-AMG ONE is the great conductor of the electric current that binds and boosts this vehicle from front axle to rear exhaust. Along with the Internal Combustion Engine, these two systems work together to create the powerhouse of this extraordinary vehicle. If the ICE is the beating heart of the AMG ONE, then the Hybrid System represents its life force – clearly set on pure power and speed.

Join us for a look at the precise and excellent system that empowers the AMG ONE to reach new dimensions of speed, agility, and performance.

What were the main challenges in designing, creating, and implementing the hybrid system? What was the main focus for this system?

We could talk about this topic for hours, but the main challenge has been combining all of these components into this complex machine. We had to be sure that the results met the development targets. A standard power train has only two components: an ICE and a gearbox. This is somewhat of a standard process in the automotive industry and is thus relatively easy to put together.

The Mercedes-AMG ONE has a few additional components, not only in the ICE, but in the entire system. The internal combustion engine is made more complex with the addition of an MGUH - a highly sophisticated electric turbo charger - as well as the integrated electric motor, the MGUK. Everything had to be optimized in various dimensions. Our power unit needed to match the ICE and the gearbox. The battery, inverters and a couple of electric motors come into play. Each component has its own limits. The battery, as an example, has an optimal operational temperature of around 50ºC in contrast to an ICE, which operates optimally at above 80ºC. All the various limits and optimal operating conditions of these components had to come together to work within this space. The secret was then to solve that multi-dimensional equation to get the best compromise in terms of efficiency, power output, and weight as the most important dimensions, along with others.

We know that this battery system is more compact, as is the rest of the engine, than other high-powered hybrid systems – how was this achieved on a technical level?

Our development target was different to that of standard EVs, which normally have a battery optimized for range and every-day driving and usage in very low and very high temperature conditions. Our modified F1 battery is optimized for power output and performance on the track. These cells are different to a standard hybrid, but we’ve used the exact same technology from F1 and scaled it for the project. It’s 4-times bigger than the F1 battery. We have a power output that is much, much higher compared to standard EVs. The maximum power output of the battery is higher than 400 kilowatts, and 360 kW are applied directly to the street via the MGUK attached to the ICE and the two on the left and right sides of the front axle. The MGUH supports the ICE and works as an additional amplifier by delivering a high level of boost pressure so that this small 1.6 liter gasoline engine produces more than 400 kW of fuel combustion power from its main power source.

How were you able to achieve a higher power capacity than a Formula 1 battery at the same time as keeping all components compact?

This is a very good question. It was somewhat similar to a game of ‘Tetris’. We had to sort all the small bricks in a way that allowed for optimal packaging and placement. We scaled up the battery and tackled the most important obstacle, which was how to integrate that larger capacity into a car without compromising its function. We couldn’t reduce the size of the cells themselves, but we could package them in a different way. There were a lot of criteria we had to respect in order to accomplish this, not only concerning weight and packaging. This also included the very important task of cooling; again, a multidimensional equation, which has a lot to do with optimization. We have had some very clever engineers on the project who have helped in achieving this.

Could you tell us about the direct liquid cooling of the battery’s cells? Why is this the preferred method of cooling? How is this different to existing cooling systems?

It's a very complex system. The first focus for the design was the direct cooling of the batteries because the cells themselves are in direct contact with the coolant and most of the surface is in contact with the cooling liquid. Exactly the same as for F1. This is the most efficient way to remove heat from the cells while charging or depleting them. This is too complex for mass production and we are not in a position to mass produce this system, but it’s the best concept on a technical level for this project. Specific sealant concepts and production processes are necessary to ensure that it works safely and reliably, also during later and prolonged usage. Our aim was to achieve the best performance without restrictions and to get the best out of every cell.

The overall design is another way in which this car is very safe. Everything is located around the middle of the vehicle, including the power unit: Battery, motors, ICE, and inverters. Everything is also connected by short HV cables. All of this is protected and surrounded by the car itself. Any damage would have to be extremely serious in order to reach the HV system. In the event that such serious damage occurs, there are safety mechanisms in place which ensure that either passengers or rescue team or any other people involved are safe and able to touch the car or be nearby. The energy inside the HV system is cut and drained to prevent any electrical voltage outside.

Torque vectoring supports the driving dynamics of the AMG ONE, how does this manifest itself in this vehicle, particularly when cornering?

Torque vectoring allows the wheel taking the outer edge of the corner and the inner edge of the corner to run independently with optimum speed and optimum torque in order to support that yaw torque of the car. It feels like you're being pulled into the corner without doing anything. It’s a huge support for the driver while pushing the vehicle and each of its wheels to the limit. The result is that you get the highest cornering speed possible and the maximum traction out of that corner simultaneously and it just feels amazing.

Does this MGUH system differ at all from a Formula 1 MGUH? How much energy is recuperated in its action?

I cannot say how any other MGUH works in other F1 cars. But I personally believe that this MGUH is different to most of the other F1 engines because the turbocharger is more or less split, meaning that the compressor of this turbocharger is sitting in front of the engine, in front of the 'V' and the turbine itself is behind, and the electric motor is in between. This is a very competitive, short design for the engine overall, especially everything around the intake and the exhaust system. We've split the hot and cold sides of it, which is good for both components and for the motor in between. It’s very tricky to make that long, connecting shaft durable because it runs up to 100,000 RPM and there are always vibrations in such a component. This involved a very long development process that needed clever solutions.

I think this development has been beneficial, especially for an F1 car. We have achieved unbelievably high efficiency, more than 80 percent, at a level never before seen from a turbine in a production engine. It’s difficult to predict exactly how much energy can be harvested under different circumstances, but more than 50 kilowatts at peak power. The average is strongly dependent on driving behavior: When running only at low revs and low torque, the result is much less than 50 kilowatts, or electrical energy needs to be deployed in order to be ready for the next tip-in so that you'll get immediate power out of it. In any case, a lot of energy can be potentially harvested and routed to either the battery or to one of the electric motors, which is the more efficient choice.

Which component is most unique and sets this battery system apart from others in Formula 1 or in the league of hypercars?

There are a few hypercars that have hybrid power trains but I think that the most differentiated element with ours is the MGUH in combination with all the electric motors. These are key to gaining this high level of efficiency, they’re the key to success. You will never see efficiency on this level in any other car. This is the first hypercar to have such a complex and efficient system.