Remember those reports suggesting Mercedes-AMG’s next-generation C63 will ditch its V8 for an electrified four-cylinder engine when it debuts in 2022? Well, while the German firm has yet to confirm the move, it may just have hinted at its plans.
Yes, the Affalterbach-based division says it is “working intensively on innovative technologies which will take performance to a new level”, confirming its “next vehicle generation will see the deployment of the electric exhaust gas turbocharger”.
Mercedes-AMG says the electric exhaust gas turbocharger is “already in the final stages of development”, created in partnership with Garrett Motion and coming “straight from Formula 1”. The firm says the system “resolves the conflicting goals between a small, fast-reacting turbocharger which achieves relatively low peak performance and a large turbocharger with a high peak performance but which on the other hand can suffer from turbo lag”.
The turbocharging system in question features a slim electric motor (measuring about four centimetres) integrated directly on the charger shaft between the turbine wheel on the exhaust side and the compressor wheel on the fresh air side.
The electronically controlled electric motor drives the compressor wheel before this accepts the exhaust gas flow, “significantly” improving immediate response from idle speed and across the entire rev range. Mercedes-AMG says turbo lag is thus “eliminated” by the electric motor.
In addition, electrification of the turbocharger enables higher torque at low engine speeds, which also “enhances agility and optimises acceleration capability” from a standstill. “Even when the driver takes their foot off the accelerator or applies the brakes, the technology of the electric turbocharger is able to maintain the boost pressure at all times, so that a continuous direct response is guaranteed,” says AMG.
The turbocharger can spin at speeds of up to 170 000 r/min and can be operated via a 48 V on-board electrical system. Interestingly, the turbocharger, electric motor and power electronics are connected to the combustion engine’s cooling circuit to create an “optimum temperature environment” at all times.
In October 2019, Autocar claimed the next-generation C63 would switch to a hybrid four-cylinder powertrain while also moving from rear-wheel drive to all-wheel drive. The publication said the third-generation C63 would employ an electrified version of Affalterbach’s latest turbocharged 2,0-litre four-pot – the M139 unit that debuted in the A45 and CLA45 in 310 kW form – before the powertrain rolled out to other AMG-badged models.