OT: electric supercharging

2002 GT Bilstein twin turbo Legacy which while exported and new-on-the-road in NZ would be very close to the JDM.

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.

Yeah, here's a blurb on Ford's Hydraulic Launch Assist.

Another alternative would be to look at the commercial potential of the KERS (Kinetic Energy Recovery System) being used on some Formula 1 cars.

Yes, and that nearly doubles to 20 HP when going at 65 mph.

"People find it difficult to believe that their car only needs about twenty horsepower to cruise along at a steady 65 mph."

The Prius' advantage is obviously entirely in city driving, where stop and go driving means a lot of wasteful time spent in idle not going anywhere. An electric engine idles at zero RPM, wasting no energy.

If on the other hand you spend most of your time cruising long distances on the highway, then your best bet is a diesel. At a given HP, the diesel engine will be turning over at fewer revs. So a Prius is the absolute best bet for people living in large cities, whereas someone living in the country might want to go with a diesel.

Of course this means that the best of both worlds would be a hybrid diesel.

I think a lot of the hybrids are doing something like that already. In F1 racing, they call this the KERS, or Kinetic Energy Recovery System.

Yousuf Khan

Yes, and that nearly doubles to 20 HP when going at 65 mph.

"People find it difficult to believe that their car only needs about twenty horsepower to cruise along at a steady 65 mph."

The Prius' advantage is obviously entirely in city driving, where stop and go driving means a lot of wasteful time spent in idle not going anywhere. An electric engine idles at zero RPM, wasting no energy.

If on the other hand you spend most of your time cruising long distances on the highway, then your best bet is a diesel. At a given HP, the diesel engine will be turning over at fewer revs. So a Prius is the absolute best bet for people living in large cities, whereas someone living in the country might want to go with a diesel.

Of course this means that the best of both worlds would be a hybrid diesel.

*** Which I fail to understand why no one has developed yet.

I haven't seen a production diesel hybrid passenger car yet (but haven't been looking either...)

But, we have a number of diesel hybrid "bucket trucks" at Seattle City Light.

There's also Kenworth

Others... Lots more to Google.

I would love to buy a diesel hybrid car.

Gasoline engines do the same already, at least those using Bosch's start/stop system. Well, it's new, but apparently a million cars have already been sold with it.