Interesting technology. While I know that an electric fan motor can move a lot of CFM, I still have trouble believing that the electric supercharger explained within the article will actually produce anything near "full boost" before the traditional turbo takes over. I could see it moving the impeller at a higher speed than low RPM exhaust would, relieving the load from the engine and significantly reducing turbo lag. I'd be interested in seeing real sustained boost produced from just the electric supercharger.
But thats its purpose, the entire system is designed to "Torque Fill" where the mechanical turbo can't. These systems use a bypass valve and extra piping.
Nissan previously experimented with electric motors directly driving the mechanical turbo's exhaust turbine via a clutch. Which actually would make a nice compact package if you can solve the heat concerns (electric motors HATE heat). In Nissan's prototype on throttle tip in, the electric motor would engage and drive the turbo directly, and once there was sufficient exhaust energy it would disengage. I think Nissan ran into reliability issues with the clutch mechanism due to the heat of the turbine transferring via the shaft.
Such a system when designed correctly could provide the same torque as massive displacement engine without its parasitic loss or inertia. Imagine big block levels of torque from idle to redline.
But the other side is that power required does not scale linearly with weight. So a 1.0L engine requires not a lot of airflow as compared with a 6.0L engine. The size of the power system needed to drive a 6.0L V8 a lot.
I'll use my RC cars as an example. This is based on catalogs from the Speed Controllers monitoring Voltage and Amperage levels during acceleration from a stand still, to their top speeds of about 50mph.
Car#1 is a 2.5lbs. It takes about 25amps @ 11.1v to accelerate to 50mph from a stand still. 11.1*25 = 277 watts.
Car #2 is a 11lb truck. It also tops out around 50mph with 14.8v, but it takes roughly 180amps during that acceleration to do it. Thats ~2650 watts.
Car#2 is 4.4 times heavier, but uses almost 10x more energy to achieve the same top speed. In fact, it uses even more than those figures because Car#1 can out accelerate Car#2 to 50mph. Car#2 is capable of exceeding 100mph when fitted with its maximum voltage of 25.2v.