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Improving efficiency



 
 
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  #1  
Old January 22nd 05, 09:49 PM
Ray Heindl
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Default Improving efficiency

Parker-Hannifin is running a competition among college students to
design a hydraulic drivetrain for bikes that's more efficient than
chain drive. "The challenge is to make the bike more efficient using
improved power transmission and energy recovery..."

http://tinyurl.com/5q32l Feel free to lie about where you're
located.

--
Ray Heindl
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  #2  
Old January 23rd 05, 02:32 AM
Mark Janeba
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Default

Ray Heindl wrote:

Parker-Hannifin is running a competition among college students to
design a hydraulic drivetrain for bikes that's more efficient than
chain drive. "The challenge is to make the bike more efficient using
improved power transmission and energy recovery..."

http://tinyurl.com/5q32l Feel free to lie about where you're
located.


Excerpt:
"A hydraulic system has potential for capturing and storing energy as
the bike goes downhill. The pump forces the fluid into a chamber called
an accumulator that later is released to provide a burst of power in
going uphill."

I'm thinking about a different kind of BURST of power one might get.

Don't think I'm gonna wanna ride one of these.

Mark Janeba

  #3  
Old January 23rd 05, 03:17 AM
(Pete Cresswell)
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Per Mark Janeba:
Excerpt:
"A hydraulic system has potential for capturing and storing energy as
the bike goes downhill. The pump forces the fluid into a chamber called
an accumulator that later is released to provide a burst of power in
going uphill."


Wasn't this the stuff of an April Fool's joke in one of the bike mags some years
back?
--
PeteCresswell
  #4  
Old January 23rd 05, 08:00 AM
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On Sat, 22 Jan 2005 17:32:50 -0800, Mark Janeba
wrote:

Ray Heindl wrote:

Parker-Hannifin is running a competition among college students to
design a hydraulic drivetrain for bikes that's more efficient than
chain drive. "The challenge is to make the bike more efficient using
improved power transmission and energy recovery..."

http://tinyurl.com/5q32l Feel free to lie about where you're
located.


Excerpt:
"A hydraulic system has potential for capturing and storing energy as
the bike goes downhill. The pump forces the fluid into a chamber called
an accumulator that later is released to provide a burst of power in
going uphill."

I'm thinking about a different kind of BURST of power one might get.

Don't think I'm gonna wanna ride one of these.

Mark Janeba


Dear Mark,

Actually, accumulators are quite safe, though a tad
heavy--look into the hydraulic ram pump invented by
MontFogelir--er, Montgolfier.

http://science.howstuffworks.com/question318.htm

Regrettably, I can't find the site with the really elegant
picture of a j-bend pipe with a cannon-ball that makes the
operation of these impossibly simple pumps clear even to me.

Joe Montgolfier
  #5  
Old January 23rd 05, 02:18 PM
Doug Huffman
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Default

Accumulators are a mature 'technology' at much higher power levels than
appropriate to bicycles. If there is a hazard then it is due to the
particular design.

I don't intend to visit the site but their project specifications will be
interesting if they really expect to improve on the chain/cog system. For
instance, the below, "power transmission and energy recovery..."


"Mark Janeba" wrote in message
...
Ray Heindl wrote:

Parker-Hannifin is running a competition among college students to design
a hydraulic drivetrain for bikes that's more efficient than chain drive.
"The challenge is to make the bike more efficient using improved power
transmission and energy recovery..."

http://tinyurl.com/5q32l Feel free to lie about where you're located.


Excerpt:
"A hydraulic system has potential for capturing and storing energy as the
bike goes downhill. The pump forces the fluid into a chamber called an
accumulator that later is released to provide a burst of power in going
uphill."

I'm thinking about a different kind of BURST of power one might get.

Don't think I'm gonna wanna ride one of these.

Mark Janeba



  #7  
Old January 24th 05, 01:18 AM
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Default

On Sun, 23 Jan 2005 13:07:59 -0800, Mark Janeba
wrote:

wrote:
On Sat, 22 Jan 2005 17:32:50 -0800, Mark Janeba wrote:

Ray Heindl wrote:

Parker-Hannifin is running a competition among college students to
design a hydraulic drivetrain for bikes ...

Excerpt:
"A hydraulic system has potential for capturing and storing energy as
the bike goes downhill. The pump forces the fluid into a chamber called
an accumulator that later is released to provide a burst of power in
going uphill."

I'm thinking about a different kind of BURST of power one might get.

Don't think I'm gonna wanna ride one of these.


Dear Mark,

Actually, accumulators are quite safe, though a tad
heavy...


I'm trying to imagine one that is **light enough** to be practical on a
bicycle - it still adds up to BOOM!, at least IMHO.

Side note to "Junkyard Wars" viewers - did you ever notice how the
hydraulic designs almost always lose - not because hydraulics are
inherently a bad idea, there's just some things they weren't meant for -
I think bikes and bodge jobs go in this category.

Mark Janeba


Dear Mark,

If you're going to try to drag this hydraulic bicycle drive
train thread off into the weeds of "practical," then I for
one refuse to pursue it!

Indignantly,

Carl Fogel
  #8  
Old January 24th 05, 01:47 AM
(Pete Cresswell)
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Per Mark Janeba:
Side note to "Junkyard Wars" viewers - did you ever notice how the
hydraulic designs almost always lose - not because hydraulics are
inherently a bad idea, there's just some things they weren't meant for -


Can anybody offer a ballpark figure for hydraulic drive efficiency vs gear?

It always seemed to me like the ideal multi-use walkbehind garden tractor would
be hydraulic drive and hydraulic PTO...

Drive bc brakes/power could be integrated into a single handgrip for each wheel
(as belt systems are today...)

PTO bc it would enable separating the accessory-joining mechanism from the PTO
power transfer mechanism - enabling a vastly simpler more trouble-free docking
system.

But nobody's doing that - and my first thought is that hydraulic systems just
soak up too many horsepower for small applications.
--
PeteCresswell
  #9  
Old January 24th 05, 02:24 AM
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On Mon, 24 Jan 2005 00:47:41 GMT, "(Pete Cresswell)"
wrote:

Per Mark Janeba:
Side note to "Junkyard Wars" viewers - did you ever notice how the
hydraulic designs almost always lose - not because hydraulics are
inherently a bad idea, there's just some things they weren't meant for -


Can anybody offer a ballpark figure for hydraulic drive efficiency vs gear?

It always seemed to me like the ideal multi-use walkbehind garden tractor would
be hydraulic drive and hydraulic PTO...

Drive bc brakes/power could be integrated into a single handgrip for each wheel
(as belt systems are today...)

PTO bc it would enable separating the accessory-joining mechanism from the PTO
power transfer mechanism - enabling a vastly simpler more trouble-free docking
system.

But nobody's doing that - and my first thought is that hydraulic systems just
soak up too many horsepower for small applications.


Dear Pete,

While this page is probably discussing engines much larger
than bicycles (40 horsepower), it finds 60-85% overall
efficiency for hydraulic drives (see section 4.3):

http://www.omax.com/drive_pump.html

Derailleur-style bicycle chains have been tested at 90% to
95% efficiency:

http://www.ihpva.org/pubs/HP52.pdf

Carl Fogel
  #10  
Old January 24th 05, 11:18 PM
RonSonic
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Default

On Sun, 23 Jan 2005 13:07:59 -0800, Mark Janeba
wrote:

wrote:
On Sat, 22 Jan 2005 17:32:50 -0800, Mark Janeba wrote:

Ray Heindl wrote:

Parker-Hannifin is running a competition among college students to
design a hydraulic drivetrain for bikes ...

Excerpt:
"A hydraulic system has potential for capturing and storing energy as
the bike goes downhill. The pump forces the fluid into a chamber called
an accumulator that later is released to provide a burst of power in
going uphill."

I'm thinking about a different kind of BURST of power one might get.

Don't think I'm gonna wanna ride one of these.


Dear Mark,

Actually, accumulators are quite safe, though a tad
heavy...


I'm trying to imagine one that is **light enough** to be practical on a
bicycle - it still adds up to BOOM!, at least IMHO.

Side note to "Junkyard Wars" viewers - did you ever notice how the
hydraulic designs almost always lose - not because hydraulics are
inherently a bad idea, there's just some things they weren't meant for -
I think bikes and bodge jobs go in this category.


I also notice that the junkyard teams using pneumatics and hydraulics always get
fresh plumbing, fitments and nubbins.

Ron

 




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