We like this. In between new product announcements, and dealing with disease-driven interruptions in the global auto market, Audi has taken to issuing a series of technical bulletins on component advances associated with its newer offerings. Think of Franklin Delano Roosevelt and the Fireside Chats he employed to great effect when it came to soothing the masses during the Great Depression. The same sort of mindset is in effect here. The subject matter is Audi’s electric-powered compressor, as used to boost the incoming intake charge on its 2020 S6 and S7.
First off, in this context, “compressor” stands for a blower augmenting the turbocharger, the beloved magic pinwheel spun by exhaust gases that rams a dense mixture through the intake ports and into the combustion chambers. Audi’s system, here seen on its 2.9-liter, twin-turbocharged TFSI V-6, utilizes a third, smaller turbine powered by an electric motor that gets its current from the hybrid vehicles’ lithium-ion batteries. Unlike the actual turbos, which require significant throttle input to function, the Electric-Powered Compressor, or EPC, is constantly turning and delivering a boosted charge to the engine. The EPC is mounted on the lower left side of the engine block, below the left-side exhaust manifold, and essentially between the actual turbochargers and their air-to-water intercooler. Even at idle, the engine is always getting some level of immediate boost, minimizing the acceleration lag associated with many turbocharged engines. The 2.9 V-6 in the S6 and S7 rates at 444hp, better than both models’ foregoing V-8, while at the same time boosting, pardon the pun, EPA estimated fuel economy by 22 percent. And the whole EPC system adds only 10 pounds to the Audi’s overall weight.