With the presentation of the AMG One, Mercedes has finally unveiled to the world one of the most anticipated hypercars of recent years. The aspect most emphasized by the Stuttgart-based manufacturer is the technological link between the latest car from the Star manufacturer and the Formula 1 team, a statement that is anything but euphemistic but based on concrete characteristics. The heart of the AMG One is indeed the same multi-victorious hybrid power unit in F1developed in the High Performance Powertrain department of Brixworth in the United Kingdom, to which are added two further electric motor generators at the front, for a total amount of five engines and a declared peak power of 1063 horsepower.
The central element of the Anglo-German powertrain remains the 1.6-liter turbocharged V6 heat engine. One of the great challenges faced by the Mercedes engineers was to adapt the same unit used on the Silver Arrows in Formula 1 so that it could also be powered by commercial fuels in circulation, replacing the dedicated petrol developed by Petronas in use on the racing single-seater. . The resulting power supply uses a mixed system, with a 270 bar direct injection system which is accompanied by indirect injection into the intake ducts, with the synergy between the two strategies aimed at containing polluting emissions within the limits set. according to the Euro 6 standard. The engine also has four camshafts, with the distribution based on a cascade of gears. The boost pressure can reach peaks of 3.5 bar, but the most interesting feature is the architecture of the turbocharger. The AMG One proposes in fact installation a split-turbofirst introduced in Formula 1 by Mercedes and subsequently taken up by the competition for the performance advantages found in the thermal engine.
The architecture of the split-turbo sees the separation between the turbine and the compressor, with the two impellers interconnected by a longer shaft, thus reducing the absorption of heat from the hot exhaust gases and keeping the air entering the engine at a lower temperature and therefore at a higher density. The spacing of the turbine and compressor also allows the position of the turbo to be lowered, with the shaft recessed in the engine bank, reducing the height of the center of gravity and the external aerodynamic dimensions. It also finds a place between the two impellers the MGU-H, acronym for Motor Generator Unit Heat, the first electric motogenerator of the hybrid part. The task of the MGU-H is to accelerate the compressor when the exhaust flow to the turbine is lacking, reducing turbo-lag and thus improving the response of the engine, as well as the availability of torque at low revs. At the same time, the MGU-H can act as a generator, exploiting the work done by the combustion gases on the turbine to convert the thermal energy into electricity and recharge the battery for greater energy availability to the other elements of the hybrid part.
The supercharged thermal engine can thus deliver a peak power of 574 horsepower at 9,000 rpmequal to a specific power of 359 hp / l. It is flanked by the second electric motor generator, the MGU-K (Motor Generator Unit Kinetic), directly engaged on the transmission shaft through a gear coupling, whose maximum power reaches 120 kW, equal to about 165 horsepower. The group consisting of combustion engine, MGU-K and MGU-H faithfully replicates the Formula 1 power unit and delivers power to the rear axle via a seven-speed transmission operated by a four-disc carbon clutch. Two additional electric motors installed at the front have been added to the centrally mounted power unit. Each motor generator delivers a maximum power of 120 kW to the respective wheel, thus opening up the possibility of implementing the torque vectoring, the differentiation of the electrical power between the two motors to electronically simulate the behavior of a mechanical differential. Each engine is also controlled by a dedicated inverter, with the two units located directly above the bottom of the car.
The power supply of the MGU-H, the MGU-K and the other two electric motors is entrusted to one 8.4 kWh lithium-ion battery, able to guarantee a range of 18 kilometers in electric. Developed in collaboration with Petronas, the accumulator boasts high power and energy densities, managing to ensure sufficient energy storage at a low weight and compact price. Among the secrets behind these characteristics, the cooling system, based on the anchor, stands out new direct immersion technology, widely used in motorsport between Formula 1 and Formula E but still not very widespread in the road sector. Contrary to traditional cooling systems based on a liquid circulating in metal plates in contact with the battery, the system used on the Mercedes-AMG One sees the cells immersed directly in the cooling oil, maximizing the heat exchange surface and with a radiator placed directly in the lower part of the accumulator. Direct cooling guarantees exceptional thermal management of the battery, keeping the cells at an average temperature of 45 ° C evenly distributed among the various units, a specific value that represents the optimal compromise between maximizing efficiency and minimizing degradation over time. accumulator. Temperature control is essential in containing energy dissipation, increasing the energy available for traction for the same number of cells used. Another characteristic aspect is the nominal voltage of the battery 800 V against the traditional values of 400 V, thus limiting the intensity of current required for the same power output and with it the energy losses, as well as the weight and dimensions of the wiring.
Parallel to the hardware, great importance is attached to the control strategies of the power unit, with five different mappings. In the “Race Safe” mode, the starting takes place electrically, with the thermal engine taking over as the power demand increases. The “Race” scenario differs from the previous one due to the constant ignition of the combustion engine, which is however used as a generator to maximize the energy availability to the battery for the electric motors. Finally, the EV mapping for a fully electric driving is accompanied by the “Race Plus” and “Strat 2” strategies, which include optimization of aerodynamic behavior. This occurs through the maximum exploitation of the ground effect, generating greater load from the bottom through the stiffening of the suspension unit and the lowering of the ground clearance of 37 mm at the front and 30 mm at the rear, thanks to the use of suspensions. active. There is also an active aerodynamic control system, acting on the exit ramp of the front diffuser, on the incidence of the rear wing and on the opening of the front grille for the admission of air into the underbody. The aerodynamic load released can increase up to five times, while from the cockpit it is possible to use the DRS (Drag Reduction System) to instantly reduce downforce in straight lines by 20%, a system that can be deactivated manually or automatically by acting on the brake pedal or by passing a certain lateral acceleration.
Overall, the Mercedes-AMG One boasts a cumulative power of 782 kW, equivalent to 1063 horsepower, which compared to the curb weight of 1695 kg correspond to a power-to-weight ratio of 0.63 hp / kg. This results in acceleration performance in the order of 2.9 seconds for the sprint from 0 to 100 km / h, while the 0-200 km / h takes place in 7 seconds, with an estimated maximum speed of 352 km / h. Finally, the tests on the combined cycle WLTP return fuel consumption of 8.7 l / 100 km, while CO emissions2 they are around 198 g / km. The declared performances and the technology used deriving directly from Formula 1 will only increase the requests to secure one of the 275 examples in which the AMG One will be built.
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