The Beating Heart of the Mercedes-AMG ONE

The Internal Combustion Engine, or ICE, is the beating heart of the AMG ONE. The team working on this fantastic machine has had to overcome many obstacles to bring it into existence. Melding high performance, high efficiency, and meeting street-legal standards for emissions, noise regulations, and safety has been a journey all its own, along with making this vehicle able to sustain running laps on the track or running down to the local shop.

Breathtaking innovations, a masterpiece of engineering and ultimate performance: Take a look inside what powers the beast that is the Mercedes-AMG ONE, a fascinating vehicle with the soul of an F1 car like no other machine on the road to date.

Adam Allsopp, Project ONE Powertrain Director at Mercedes-AMG High Performance Powertrains, has made it his personal mission to make the impossible, possible. We spoke to him about the most significant technical aspects of the AMG ONE’s Internal Combustion Engine and the components that comprise this, in his words, ‘car that is totally different to anything I’ve driven before’.

This was an enormous undertaking on all fronts with a team who had been in the business of designing machines to race and who had never done this before.

Can you tell us about how proud you are of this engine and what is the most exciting fact about it?

Our team is extremely proud of this engine. No one else has been able to take a Formula 1 engine, a machine intended to win races by achieving the highest efficiency and power output, without regard to emissions or noise, and adapt it so that it meets all the prerequisites for driving on public streets. We have reached the final stages of making this happen.

What was your overall focus in developing the ICE?

Our primary focus was to make this engine more durable than that of a classical racecar. A Formula 1 engine can only withstand a few races before needing to be replaced. Currently our engine lasts 31,000 km. Both the ICE and the electric motors were adapted, but the technical principle of the Formula 1 car is still intact. The ICE is more or less exactly the same. After this, our next hurdle was particulate emissions. A Formula 1 engine produces high emissions without a catalyst and filter, and gaseous emissions play a role here as well. We optimized combustion with high charge motion in-cylinder, along with in-cylinder vaporization, added a second, port fuel injection system, and the latest in filter and catalyst technology in order to reach the correct levels.

What were the greatest triumphs during development and implementation in the AMG ONE? What were the biggest technical challenges in the development of this engine?

The greatest challenge for us, overall, was taking a racing engine and making it drivable and usable not only on the track, but also able to handle a traffic-jam. For comparison, a Formula 1 car idles at a speed of 4,000-5,000 RPM – this is not doable in an urban setting. Not only is it far too noisy, it would also lead to higher emissions under normal, urban driving conditions. The addition of the electrical front axle also assured that a driver could operate the vehicle in a city without issues and under any conditions. Crash tests and safety requirements were another challenge we have faced that was different to working with a Formula 1, purely racing-focused engine.

This was an enormous undertaking on all fronts with a team who had been in the business of designing machines to race and who had never done this before. One of the greatest triumphs we’ve experienced was receiving pass-by testing certification. I’m very happy with where the results are now and where we’re headed. On top of this, we’ve broken the unofficial lap record for a public road car on a UK racetrack by two seconds within the first testing day. The positive feedback we’ve received from drivers, that this car is not only amazingly quick, but that it’s easy to drive as well, is also a massive triumph for us.

This is one of the most fantastic features because it’s a combination of an enabler of high power output and high efficiency in one. Thermal energy is put back into use from the exhaust. The MGUK is integral in feeding additional power to the rear axle, along with the electrical front axle, which has inputs of 120 kilowatts on each side. All of these components work together to allow the vehicle to drive in either EV mode, or a combination of EV and rear axle modes. The hybrid system and ICE together amount to a system output of over 1,000 horsepower. Our front axle also has a very positive effect on vehicle dynamics via torque vectoring. This is a wonderful tool for steering and especially for cornering.

We optimized in order to increase boost level without affecting drivability. Usually, the turbocharger is only driven by the exhaust flow, meaning that there is always a lag if you have a tip-in as a driver. Boost pressure must first be created by the power of the turbine transferred to the compressor. In this case, the electric motor spins up the turbocharger to create enough boost pressure on the intake side, thus producing immediate power. A tip-in means receiving a high boost level which has a positive, dynamic effect on the drivability of the car. Efficiency is increased as the turbine acts as a generator for the electric motor by using thermal energy that would normally be wasted. This energy is fed to the front axle or to the battery instead of only producing hot exhaust gas.

In a Mercedes road car with a hybrid engine that runs at 7,000 RPM, the electric motor would also be running at the same rate – 7,000 RPM. Our electric motor, the MGUK, is running at more than 30,000 RPM and creates maximum power at higher speeds, not just from zero. The electric motor offers very sporty power distribution in regard to revolutions. Its big advantage is the combination of the electric motor with a high-rev concept, extremely high efficiency, and a gear train behind to couple it directly to the crank, resulting in a very light design. It looks a bit like the starter of a standard combustion engine. You would never imagine that the MGUK has a power output of 120 kilowatts. It's very, very small, and can be integrated completely into the ICE.

The basic idea is similar to a gas turbine as it produces high revs and high power density. We use exactly that concept also for the electric motors on the front axle where it revs up to over 50,000 RPM. This works in combination with one gear connected to the front axle to create the correct speed for each wheel. Maximum power is also produced in high speed conditions.