|A Volvo experimental electric turbocharger. Photo courtesy of Volvo.|
With stricter government regulations in the United States and abroad, automakers are working like crazy to squeeze as much power as possible from small engines. Turbocharging is one way to do this, but it comes with some drawbacks. I've owned a few turbo cars, and each one suffers to one extent or another from turbo lag, so you literally wait for the turbocharger to spool up before you feel the rush of power from it. Granted, this isn't as bad with some setups as others, but even in twin-scroll configurations turbo lag is a factor. Turbos also recycle exhaust gases, cooling them off some before forcing them back into the engine. Because of this arrangement, you really have to stay on top of the oil and coolant levels or you could be dealing with a huge overheating problem. Even if you monitor things closely, you could still suddenly see steam pouring out from under your car's hood. On the flip side, turbo cars always have heaters that work great.
Electric turbos present the benefits of a turbocharger but without the usual drawbacks. Instead of using exhaust gases, the system draws in fresh air, which helps cut down on the heat problems. You could argue that they're really centrifugal superchargers, and you are pretty much correct in that statement.
Turbo lag is literally nonexistent. Since an electric turbocharger is powered by an electric motor and not the exhaust gases produced by the engine, the setup allows for almost immediate power delivery. Not only does that translate into more fun, it also means the engine is using less fuel and so contributes to greater fuel economy.
The setup also takes up less space, which is great news in cars that have a crowded engine bay. There are no downpipes, intercoolers or any other additional piping that is necessary with a traditional turbo.
Right now, electric turbos are still only a concept. Even though they aren't used in any production models, yet, the likelihood they will is rising. So far Audi, Volvo and Ferrari have all publicly revealed they are experimenting with the technology. Expect other automakers are doing so behind closed R&D doors.