Perhaps you saw the experimental engine under development at Volvo. It’s a 2.0-liter gasoline-powered four-cylinder that cranks out an amazing 450 horsepower. At 225 horsepower per liter, it would be one of the most power-dense engines ever produced, if Volvo decides to build it.
How Volvo engineers boosted the output of the engine is extremely smart. Two turbochargers plumbed into the engine’s intake system are powered not by exhaust gases — the normal way — but by air pressure generated by what I would call a third turbocharger.
It’s not clear what that third device is. It looks like a turbocharger, but the turbine on the exhaust side has been replaced with an electric motor. Volvo calls the unit an “electrically powered turbo compressor.” But French supplier Valeo, which makes a similar device, calls theirs an “electric supercharger.”
OK, engineers, gearheads and engine builders out there, we need some help with this one. Here’s the question: If you change the power source of a turbocharger from exhaust gases to a high-revving electric motor, is the device still a turbocharger or something else? Give us your feedback below.