Well, that's already being done, and it doesn't result in any fuel
savings, in fact it likely has higher fuel consumption. I think that
this electric supercharger is for fuel economy rather than all-out
performance. A larger turbo charger on a small engine will not even
come on till very high in the RPM range. The larger turbo will result
in less intake obstruction when the turbo is not running. The
supercharger will only get turned on in very special circumstances. It
seems the whole idea of the engine is to not Xcharge it at all, or
wait till the last moment to bring on one of the chargers. While it's
not being Xcharged, it is saving fuel.
Yousuf Khan
to me, that just seems backwards. A turbo is an 'energy recovery'
device (granted, with limitations) but a supercharger seems to require
'primary use' energy in either fuel for direct-drive, or fuel for
battery/cap charging w'ever. And since inertia is the big requirement
for energy, slow acceleration IS a fuel saving aspect. Quick
acceleration is what costs fuel. That is why regnrative braking will
be the primary form of any advances in fuel savings. That is why the
Prius has such great city driving mpg numbers. It can throw braking
energy into the battery pack.(some - not all). That is also why
things like hydrogen and veggie oil will only be transitive
alternatives. Any viable future car drivetrain must have a way to
perform regen-brkng . Either with compressed air, or hydraulic
accumulators or electric battery charging. (Of course a hydrogen/
electric or veggie oil /electric hybrid could do regen-brkng).
A physicist I worked with in a previous job did an experiment in his
full-size chevy truck. To cruise on the highway at 55mph only required
12 horsepower. 12hp. The reson an engine needs 150-200 hp or w'ever is
for acceleration - overcoming inertia to GET to cruising speed. That
is why the Prius doesn't really offer an advantage over other small
cars in highway mileage. No braking, no energy to recover/re-use.
If a capacitor bank could be charged with some braking energy, then
dumped into an 'assist from stop' electric motor OR ,maybe' and
electric turbocharger - you might see some fuel savings. As another
poster said, put an electric motor on the flywheel or drive shaft and
just use it for pulling away from a stop.