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Mercedes introduces new SL model with electrically assisted turbocharger

23 May 2023

Mercedes-AMG is introducing in the North American market the SL 43—a new entry model for the AMG SL roadster powered by a 2.0-liter turbocharged M139 engine featuring an electrically assisted exhaust gas turbocharger. This technology is a direct derivative of the development used by the Mercedes-AMG Petronas Formula 1 Team.

The electric turbocharger provides spontaneous throttle response across the entire rpm range, solving the trade-off between a small, responsive turbocharger yielding a lower total output and a large turbocharger capable of high peak power with less responsiveness.

The operating principle of the electric exhaust gas turbocharger is based on the same technology used by the Mercedes-AMG Petronas F1 Team. An electric motor around 1.6 inches (4 cm) thick is integrated directly on the turbocharger shaft between the turbine wheel on the exhaust side and the compressor wheel on the intake side. This electronically controlled motor accelerates the compressor wheel before the exhaust gas flow takes over the drive in a conventional manner.

The electrically assisted exhaust gas turbocharger significantly improves immediate response from idle and across the entire rpm range, Mercedes said. In addition, the electrification of the turbocharger enables higher torque at low engine speed. Even when the driver takes their foot off the accelerator or applies the brakes, the turbocharger is able to maintain the boost pressure at all times to ensure a continuously direct response.

The turbocharger is operated via a 48-volt electrical system, which also feeds a belt-driven starter-generator (RSG). The turbocharger works at speeds of up to 170,000 rpm. The turbocharger, electric motor and power electronics are connected to the combustion engine’s cooling circuit to create an optimal temperature environment.

The second-generation RSG also functions as a mild hybrid in the 48-volt on-board electrical system enabling functions such as gliding and recuperation to maximize efficiency.

The engine uses a combination of direct gasoline injection and intake manifold injection for mixture formation. In combination with the AMG-enhanced M139 engine, the AMG SL 43 produces its output of 375 hp at 6,750 rpm. The 354 lb-ft (481 Nm) of torque is available between 3,250 rpm and 5,000 rpm. The AMG SL 43 accelerates from 0 to 60 mph in 4.8 s on its way to an electronically limited 170 mph (274 km/h) top speed.

The AMG SL 43 will arrive in US dealerships in Summer 2023, starting from $109,900. In Europe, Mercedes-AMG announced the SL 43 model last year, but it wasn’t sure if this version would be sold in North America. The electrically assisted turbocharger was developed in partnership with Garrett Motion.

Source: Mercedes-Benz