Mercedes-AMG Project ONE: Formula 1 technology for the road, one turbo engine and four electric motors
The high-performance plug-in hybrid drive system of the Mercedes-AMG Project ONE comes directly from Formula 1, and was realised in close cooperation with the motorsport experts of Mercedes-AMG High Performance Powertrains in Brixworth. It consists of a highly integrated and intelligently networked unit comprising one hybrid, turbocharged combustion engine with a total of four electric motors. One has been integrated into the turbocharger, another has been installed directly on the combustion engine with a link to the crankcase and the two remaining motors drive the front wheels.
The 1.6-litre V6 hybrid petrol engine with direct injection and electrically assisted single turbocharging comes directly from the Mercedes-AMG Petronas Formula 1 racing car. To achieve high engine speeds, the mechanical valve springs have been replaced by pneumatic valve springs. The vehicle is mid-engined (ahead of the rear axle) and it can easily reach speeds of 11,000 rpm, which is currently unique for a roadgoing vehicle. However, for higher longevity and the use of commercially available Super Plus petrol instead of racing fuel, it remains significantly below the F1 engine speed limit.
The electric motors on the front axle are also true rev wonders, with rotor revolutions up to 50,000 rpm – current state of the art is a speed of 20,000 rpm. The very high-revving engine is additionally boosted by a high-tech turbocharger. The exhaust gas and compressor turbines are separated from one another and located at an optimum position to the exhaust side and to the intake side of the V6 engine, and connected to one another by a shaft. This shaft features an electric motor with approximately 90 kW which, depending on the operating status, electrically drives the compressor turbine with up to 100,000 rpm – for instance when moving off or following load changes. The Formula 1 designation for this unit is MGU-H (Motor Generator Unit Heat).
The major advantage: the dreaded turbo lag – the delayed response to accelerator pedal commands owing to the inertia of the large charger – is completely eliminated. The response time is greatly reduced, and is even shorter than that of a naturally aspirated V8 engine. The electric turbocharger brings about another advantage: it uses parts of the surplus energy from the exhaust system to generate electricity, and either stores it in the high-voltage lithium-ion battery as part of recuperation or provides additional drive power by feeding it to an additional electric motor. This motor produces 120 kW, has been installed directly on the engine and features a link to the crankshaft via a spur gear (MGU-K = Motor Generator Unit Kinetic) – another technology that ensures maximum efficiency and performance in Formula 1.
The thermal efficiency of the combustion engine with electric turbocharger (MGU-H) in conjunction with the electric motor on the crankshaft (MGU-K) will be over 40 percent. This is a previously unattained peak value for series production vehicles. There will also be two further 120 kW electric motors at the front axle.
Each is connected to a front wheel via a reduction gear. The fully electrically driven front axle allows individual acceleration and braking of each front wheel, and therefore selective torque distribution for particularly high levels of vehicle dynamics.
The driver can move off purely electrically, initially with just the electric motors on the front axle driving the hypercar and the electric motor on the crankshaft supporting short-term acceleration wishes. If the driver presses the accelerator more firmly and demands more output, the V6 engine also switches on. The drive system unfolds its full power as the engine speed increases. Impressive acceleration figures are possible with the Race Start function: acceleration from zero to 200 km/h takes under six seconds. If the driver’s foot leaves the accelerator again to let the car coast, the system switches to electric drive at the front axle – whilst braking under normal driving conditions recuperates up to 80 percent of the energy, which is fed into the battery.
The Mercedes-AMG Project ONE will not only be an ultimate driving machine that directly brings current Formula 1 hybrid technology onto the road and combines top-class race track performance with full day-to-day suitability. Its purpose is also to obtain extensive findings about performance-oriented plug-in hybrid drive technology, further developments of suspension layouts and extended onboard electronics that will later benefit series production AMG cars.