For the people that moan about electric turbos on ebay...
Discussion
hman said:
Whatever, the guy before talked of a "supercharger" requiring huge forces -hence why I was talking about the difference between the commonly accepted usage of the word super charger in the context of cars with scrolls and or twin screws (not a turbo) and an EDF.
whether you use scrolls, screws, EDFs or lots of bike pumps, you need 10s of HP to provide reasonable boost for a typical car engine. More if you use something with crap efficiency.hman said:
For all your regurgitations you still haven't worked out if an edf with 11 lbs of thrust would work as a turbo charger have you..
The problem is, you need power to compress air, not force. It's like asking if a car with a 1000lbft engine can do 100mph! (ie, not necessarily!). However, at a guess your 11lbf EDF is probably 10 - 20% of the size neededI worked it out once - IIRC it was around 10 kw.
The maths is easy : p = fv, f= pressure x area. So for the hypothetical 3 litre, imagine feeding it at 7 psi boost through a 4" diameter inlet. Force is 7 * pi * 4 pounds, velocity is airflow / area, airflow = capacity * revs (scaled to whatever units).
So power required is proportional to boost and revs, which is logical.
I did it in SI units to make the maths easier, but I cbf doing the maths at this time of night (on my side of the world).
The maths is easy : p = fv, f= pressure x area. So for the hypothetical 3 litre, imagine feeding it at 7 psi boost through a 4" diameter inlet. Force is 7 * pi * 4 pounds, velocity is airflow / area, airflow = capacity * revs (scaled to whatever units).
So power required is proportional to boost and revs, which is logical.
I did it in SI units to make the maths easier, but I cbf doing the maths at this time of night (on my side of the world).
hman said:
kambites said:
It's not the volume at atmospheric pressure that makes those things rather unviable, it's the volume at significant pressure.
As for how much, well a 3 litre four-stroke engine will have a swept capacity of 1500cc per revolution; say 6000rpm peak = 100 hz = 150 litres per second N/A. If you want to get 1 bar of boost, you'd need to add another 150 litres per second under pressure.
4st engine is only sucking in the air on every alternate stroke ..As for how much, well a 3 litre four-stroke engine will have a swept capacity of 1500cc per revolution; say 6000rpm peak = 100 hz = 150 litres per second N/A. If you want to get 1 bar of boost, you'd need to add another 150 litres per second under pressure.
http://www.centralturbos.com/pop-werks5a.htm
Edited by kambites on Tuesday 30th July 17:19
Are we forgetting that this acts as the warm up man, at lower engine speeds to fill in while the main turbo starts doing its thing.
My thinking is that the engine doesnt need as much air at lower engine speeds, as this filling in at the low end is covered by the electric blower the main turbo can be bigger as it isnt needing to be as much of a compromise in terms of size.
Also the ariticle says it needs a change to 48 volt electrics to become a reality.
Could work quite well in a hybrid application as all the battery stuff is there.
My thinking is that the engine doesnt need as much air at lower engine speeds, as this filling in at the low end is covered by the electric blower the main turbo can be bigger as it isnt needing to be as much of a compromise in terms of size.
Also the ariticle says it needs a change to 48 volt electrics to become a reality.
Could work quite well in a hybrid application as all the battery stuff is there.
J4CKO said:
Are we forgetting that this acts as the warm up man, at lower engine speeds to fill in while the main turbo starts doing its thing.
I read it as being a combat for lag rather than boost threshold (well, maybe both), in which case it needs to work at all engine speeds. Edited by kambites on Tuesday 30th July 17:39
hman said:
scarble said:
hman said:
4st engine is only sucking in the air on every alternate stroke ..
http://www.centralturbos.com/pop-werks5a.htm
Which is why he says 1.5l per cycle from a 3l engine http://www.centralturbos.com/pop-werks5a.htm
hman said:
The electric ducted fan is a turbine in a shroud not a supercharger compressor (ie a scroll or twin screw setup)
No it's not, a turbine is a device which is worked upon by a fluid to produce mechanical work, a ducted fan is a device which uses mechanical work to produce work upon a fluid. A typical turbocharger compressor is actually a radial flow or centrifugal compressor (so neither a scroll or twin screw which granted are typical mechanically driven supercharger configurations)
But axial flow compressors are not used (queue someone coming up with some weird concept from the 50s to make me look silly) although there have been murmurs of axial turbines (as opposed to the typical radial flow ones used in cars) (I think they work better for very low flows or something?).
For all your regurgitations you still haven't worked out if an edf with 11 lbs of thrust would work as a turbo charger have you..
Pop that in your Wikipedia pipe and smoke it.
Also, if you know EDF you'll know that ducting is critical and they are extremely sensitive to changes in cross sectional area. Choke down the efflux much more than 70ish% give or take and you simply stall the fan, not compress the air behind it.
A ducted fan can accelerate air at a relatively constant pressure - infact it relies on the incompressibile preferences of air to work at all.
To overfill piston engine cylinders you either need a centrifugal compressor or a positive displacement pump such as a screw or roots type compressor.
hman said:
scarble said:
hman said:
4st engine is only sucking in the air on every alternate stroke ..
http://www.centralturbos.com/pop-werks5a.htm
Which is why he says 1.5l per cycle from a 3l engine http://www.centralturbos.com/pop-werks5a.htm
hman said:
The electric ducted fan is a turbine in a shroud not a supercharger compressor (ie a scroll or twin screw setup)
No it's not, a turbine is a device which is worked upon by a fluid to produce mechanical work, a ducted fan is a device which uses mechanical work to produce work upon a fluid. A typical turbocharger compressor is actually a radial flow or centrifugal compressor (so neither a scroll or twin screw which granted are typical mechanically driven supercharger configurations)
But axial flow compressors are not used (queue someone coming up with some weird concept from the 50s to make me look silly) although there have been murmurs of axial turbines (as opposed to the typical radial flow ones used in cars) (I think they work better for very low flows or something?).
For all your regurgitations you still haven't worked out if an edf with 11 lbs of thrust would work as a turbo charger have you..
Pop that in your Wikipedia pipe and smoke it.
Also, if you know EDF you'll know that ducting is critical and they are extremely sensitive to changes in cross sectional area. Choke down the efflux much more than 70ish% give or take and you simply stall the fan, not compress the air behind it.
A ducted fan can accelerate air at a relatively constant pressure - infact it relies on the incompressibile preferences of air to work at all.
To overfill piston engine cylinders you either need a centrifugal compressor or a positive displacement pump such as a screw or roots type compressor.
205alive said:
What if you had a bottle of liquid oxygen with an EDF plumbed into the intake manifold? So as you floor it, the O2 valve opens as soon as the EDF spins up to speed, chucking compressed O2 down the inlet?
So what's the EDF doing for you? If you've got pressurised Lox in a bottle, you don't need an EDF getting in the way :-(Monty Python said:
Face for Radio said:
Leaf-blowers in the intake have been proven to work. Bit impractical though. There's a video online of some yanks doing it with some sort of horrible music dubbed over.
http://www.youtube.com/watch?v=cbGWgvJN1_8&list=HL1375195687&feature=mh_lolzFairly thorough video about supercharging a car with leaf blowers. It does work, to a degree.
https://www.youtube.com/watch?v=U81_0waqEWA
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