AMG switches to electric turbocharging

Electric superchargers started appearing on production cars four years ago: the first was the Audi SQ7 crossover, and now Daimler and Land Rover are also using the technology. Their engines have the usual turbochargers and a separate electric supercharger in which a single compressor wheel is driven by an electric motor. And AMG and Garrett have combined these two types of supercharger and introduced an electric turbocharger as standard.

Previously, this technology was only found in racing engines (e.g. Formula 1). Its essence is that a miniature (4 cm thick) but very powerful electric motor is installed on the shaft between the turbine and compressor wheels, which runs from a 48-volt mains supply, is included in the general engine cooling system circuit and is capable of spinning up to 170,000 rpm.

It kicks in almost immediately after the accelerator pedal has been depressed, without waiting for the exhaust gas flow to accelerate the turbine wheel. In this way, the electric motor compensates for the turbo lag, but unlike previous designs, there’s only one supercharger instead of two. In addition, the electric motor can maintain boost pressure when the throttle is briefly released.

The developers promise that engines with such a supercharger combination will appear in next-generation Mercedes-AMG vehicles.