Electric superchargers to offer affordable hybrid solution

Electric superchargers as part of an affordable hybrid system for heavy-duty trucks and buses have come a step closer.

Because they would be switched in and driven by an external electrical source, they would offer near instantaneous response to throttle inputs compared to an exhaust-gas driven turbocharger, allowing engine downsizing without compromising vehicle performance. Fuel savings of up to 10 per cent are projected, along with reductions in nitrogen oxides (NOx) and particulate output.

Controlled Power Tech-nologies (CPT) demonstrated its Cobra (Controlled Boosting for Rapid Response Applications) device at the Supercharging Congress held in Dresden last autumn.

CPT chief executive Nick Pascoe said: “CPT’s family of heavy-duty compressors has been developed as original equipment for a wide range of diesel engines in off-highway and commercial vehicles using either 24V or 48V architecture in a low cost hybrid system.

“Cobra builds on the experienced gained by commercialising our VTES electric supercharger for passenger cars. We sold our VTES business to Valeo in late 2011, and now focus on trucks and buses.”

Sales manager Dirk Zepp said: “It’s an efficient way of using two-to-nine kW of stored electrical power. And depending on the rate of fuel injection, this can mean an additional 15-70bhp (20-90kW) at the crankshaft for up to 30 seconds.

“Cobra is beneficial in reducing diesel tailpipe emissions of urban buses and trucks with their continuous stop-start operation. Another major environmental advantage of our switched reluctance technology is the elimination of permanent magnets in our electrical machines, which replace the need for expensive rare earth metals by using integrated electronic switching.”