It seems that the British are leading the charge once again. But instead of a battalion of Queen’s finest men dressed in their choicest freshly pressed uniforms, they are waging a war against carbon dioxide emissions.
Before that, we’ll circle around that just for a minute. Electric-assisted forced induction is a great bit of kit. We’ve seen electric turbocharging in action before. Look no further than the pinnacle of motorsports – Formula One. But why do F1 cars need electric turbochargers? Simple. With the downsizing trend that’s crippled the sport’s popularity ratings, it has also taken a toll on the engines. As compared to the previously-used V8 motors that had instant torque and power on demand, these cars now suffer from two dreaded and very familiar words – turbo lag.
Now, to eliminate this problem and to keep the cars competitive under ridiculously stringent regulations, the solution was simple. It wasn’t perfect but it worked. But this isn’t Formula One and we ordinary folks aren’t always in a hurry, although most beg to differ on that point. Much like the e-turbo’s in F1, an electric supercharger looks and acts a lot like a turbocharger, and its job is to compress air that is then used to spin up a conventional turbo. British firms, Controlled Power Technologies (CPT) and Eminox have come together in a collaborative effort to develop an electric supercharger, but it isn’t for use on cars just yet, but rather for larger heavy duty diesel vehicles.
The result of all those sleepless nights is the world’s first water-cooled electric supercharger unit developed for continuous boosting of commercial diesel and gasoline engines that’ll produce the cleanest engines by delivering a necessary amount of air very quickly and precisely for optimum combustion, particularly during transient or short driving cycles.
Having said that, e-superchargers allow engineers to downsize the cubic capacity of big-bore oil burners currently powering a whole range of heavy vehicles. The beauty of this technology is that it can used on existing engines. You don’t have throw away your trucks or what have you and get new ones that come with this new tech, because it’ll work in tandem with engine-driven turbocharger. Trucks don’t run on 12-volters we’d typically find in our cars, so this works to the advantage of the e-supercharger.
The electric supercharger ensures that truck operators need not always be on the loud pedal to extract power from the oil burner to get around. The supercharger will automatically maintain the ideal boost measure and ensure constant power delivery throughout. CPT developed Cobra, a tech that includes a sealed-for-life bearing system, coupled with electronics that are state-of-the-art. Combined that with a radial compressor connected to an ultra-low inertia rotor, the device accelerates from idle to 60,000 rpm in less than half a second to provide instantaneous boost, thereby avoiding transient torque and smoke issues.
The electric supercharger technology developed by CPT is not driven by conventional electric motors, but rather a powerful switched reluctance motors controlled using advanced electronics and software. Switched reluctance motor generators eliminate the need for expensive rare earth materials required for high speed permanent magnets. Moreover, low inertia means they can respond much faster than a conventional turbocharger. They are also highly efficient where they are most useful, which is at low engine revolutions where the main turbo lacks boost. This makes electric superchargers using switched reluctance machines an enabling technology to reduce engine size.
However, in tropical applications for cars, this is a different story all together. Impossible is nothing, but difficult it surely is. Forget about retrofitting, it much cheaper to just buy a Prius. The e-supercharger has to be hooked up to a DC electric motor. The way most normal cars are hooked up, it just won’t cut the mustard here. The answer is high-density quick charge/discharge batteries or better still a supercapacitor, but those are really expensive. Not only that, but they are live longer than conventional batteries in terms of repeated charge and discharge.
Ideally, having an energy recuperating system such as KERS (a system which draws kinetic energy via braking to charge a battery pack) can be a viable option for e-supercharging. When power is needed, the battery pack will drive juice out via an AC/DC converter for voltage correction before powering the supercharger, making it a win-win situation.