P3 Hybrid System in the Mercedes-AMG C 63 S E Performance

Mercedes is ditching the V8 engine in favour of a highly sophisticated PHEV system called P3 Hybrid for the new Mercedes-AMG C 63 S E Performance. We try to explain how it function.

The P3 Hybrid system of the Mercedes-AMG C 63 S E Performance consists of the 2-litre M139l turbo engine and an electric motor that distributes power to all four wheels via a 4Matic+ all-wheel drive system. The electric motor is located at the rear axle and is integrated into a compact electric drive unit (CDU) with an electrically operated two-speed gearbox and limited slip differential.

The electric motor can also distribute power to the front axle if required

The second gear of the transmission engages at around 140 km/h, which corresponds to the electric motor’s maximum speed of 13,500 rpm. Normally, the electric motor drives the rear axle, but if rear axle slip occurs, it is possible to transfer some of the electric motor’s power to the front wheels. The mechanical connection of the fully variable all-wheel drive system allows this via a propeller shaft and the drive shafts of the front wheels. The electric motor develops 204 HP and 320 Nm which are available any time via the kick-down function. The continuous power is 70 kW.

Electrically driven turbocharger 

The 2-litre thermal engine is derived from the 421 HP engine in the AMG A 45 and is coded M139l where l signifies that it is longitudinally mounted whereas in the A 45 it is transversely mounted. This means that power is transmitted to the rear axle via a cardan shaft. Then, in case of rear axle slip, the same propeller shaft used to transmit part of the electric motor power to the front wheels also transmits part of the heat engine power to the front wheels.

The thermal engine develops 476 HP/6725 rpm and 545 Nm/5,250-5,500 rpm. With a power output of 238 HP/litre, the M139l is the world’s most powerful 4-cylinder engine. This was only made possible by the use of an electrically driven turbocharger which I have written about here before.

The technology is borrowed from Formula 1 and consists of an electric motor only 4 cm thin integrated directly on the turbine shaft between the turbine wheel on the exhaust side and the compressor wheel on the intake side. This means that the turbocharger response is no longer dependent on exhaust gas flow, but is controlled electrically and so the response is instantaneous at low revs.

The turbocharger motor is powered from the PHEV system’s 400V network and operates up to 150,000 rpm. The engine has an integrated starter generator (RSG) also powered from the 400V network. Power is transmitted through a 9-speed AMG Speedshift MCT 9G automatic transmission in which a wet start-off clutch replaces the classic torque converter.

Nine programs 

The driver has at his disposal no less than nine programs that adjust not only the engine, gearbox, steering and suspension response and engine sound but also the boost power of the electric motor.
Electric program: the car runs solely on the electric motor at a top speed of 125 km/h. But as mentioned above, the mechanical connection to the AMG Performance 4Matic+ components means that all-wheel drive is available in this mode too. The 89 kg battery with direct cooling system, located above the rear axle, has a capacity of 6.1 kWh and can be charged at AC stations with 3.7 kW giving a range of 13 km.
Comfort program: in this mode, the car starts with the electric motor and the two engines run together but at low speeds the electric drive is favoured. The boost power of the electric motor is limited to a maximum of 25%.
Battery Hold program: similar to Comfort with the exception that the battery charge level is kept constant.
Sport program: the car starts with both engines and the boost power of the electric motor goes up to 65%.
RACE program: Both engines run and the power boost of the electric motor increases to 80%. Boost Mode can be accessed from the button on the left arm of the steering wheel.
Slippery program: power and torque are reduced. Energy recuperation (avilable on four levels) and pure electric propulsion are disabled.
Individual program: allows individual setting of various parameters.

The Mercedes-AMG C 63 S E Perfromance comes standard with AMG Ride Control with Adaptive damping suspension and integral steering which is also offered on the C-Class but the steering angles are different: up to 100 km/h the rear wheels turn in the opposite direction to the front wheels by 2.5 degrees and above 100 km/h they turn in the same direction by up to 0.7 degrees.

Values in brackets are for the T-Model version