OT: electric supercharging

[clare]

What a great idea!


Figured somebody probably would.


Assuming it worked; which it probably wouldn't.


There is a cost to everything; power is never free.

Better to just couple the big series wound motor directly to the
driveshaft and use the INSTANTANEOUS torque of the series motor to
provide the extra accelleration torque.

 

[JD]

Better to just couple the big series wound motor directly to the
driveshaft and use the INSTANTANEOUS torque of the series motor to
provide the extra accelleration torque.

I agree. But wouldn't we call that mechanical supercharging?

 

[bugalugs]

What do you drive, a JDM TT Legacy by any chance?
Martin

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

 

[YKhan]

Why not just use a smaller turbo?  It would have the same effect.

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

 

[1 Lucky Texan]

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.

 

[1 Lucky Texan]

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.
http://www.autoblog.com/2006/02/14/ford-f-150-to-debut-with-hydraulic-hybrid-system/

 

[bugalugs]

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.

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

 

[YKhan]

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.

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."
http://zfacts.com/p/821.html

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.

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.

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

 

[JD]

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.

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."
http://zfacts.com/p/821.html

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.

 

[nobody >]

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
http://awakeatthewheel.net/2008/08/22/kenworth-diesel-hybrid-truck-prius-with-muscle/

Others...
http://trucks.about.com/cs/militarytrucks/a/gm_miltary.htm

Lots more to Google.

 

[JD]

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
http://awakeatthewheel.net/2008/08/22/kenworth-diesel-hybrid-truck-prius-with-muscle/

Others...
http://trucks.about.com/cs/militarytrucks/a/gm_miltary.htm

Lots more to Google.

I would love to buy a diesel hybrid car.

 

[Anssi Saari]

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.

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.