Electric water pumps (was) alt charging cont sw

Roy spectric at yahoo.com
Mon Mar 15 08:19:15 GMT 1999


Roy Spectric's wrote:

Hi

Reading these threads with interest, and must ask why are so many
manufacturers now going over to electric power steering pumps, Peugot
are using it in production and ford are looking into it if there are
no advantages.

With a cooling pump i would have thought it would have a much narrower
speed range in which it is at it's most efficient compared to the
engines rpm range.

So if it was electric and it's speed independant of engine speed then
it could operate more efficient.

At continous high engine speed the average water pump is tending to
aerate the coolant leading to cavitation.

---Greg Hermann <bearbvd at sni.net> wrote:
>
> >Bruce Plecan wrote:
> >>
> >> -----Original Message-----
> >> From: Clive Apps Techno-Logicals 416 510 0020
<clive at problem.tantech.com>
> >> To: diy_efi at efi332.eng.ohio-state.edu
<diy_efi at efi332.eng.ohio-state.edu>
> >> Date: Sunday, March 14, 1999 12:25 PM
> >> Subject: Re: Electric water pumps (was) alt charging cont sw
> >>
> >> OK, but a 1-2 HP electric motor is alot of weight, no?.
> >> Then the waterpump coupling (mechanial/coolant), and pump itself.
> >> Now a hydralic pump is another matter, since at low speed it's
use could be
> >> shared with the power steering, or for running a supercharger off
of
> >> hydralics.
> >> Bruce
> >
> >Just FYI, Summit shows 4 electric water pumps, 2 race only and 2
that I
> >guess are OK for street.  5.8 amps for the street one, 3.5 for the
race
> >pump.  That's about 72 watts for the street pump, or about a tenth
of a
> >HP.  30-35 gpm flow, 9psi static pressure.  They're real proud of
them,
> >at $260 for SBC.
> >
> >Can any mechanical guys speak up on if a constant rpm pump gains
enough
> >efficiency over a variable rpm pump to make up for the
> >mechanical/electrical/mechanical conversion?
> 
> You still need more water flow AND head at higher engine speeds!
> 
> Greg
> >
> >--steve
> >
> >>
> >> >> Think about how much motor/pump it takes to do 100 GPM....
> >> >> (I'm guageing this on the 180 GPM Stewartcomponents mentions
> >> >> at 9,000 rpm).
> >> >> You might need 10-15 at idle..
> >> >> Or am I missing something here
> >> >> Bruce
> >> >
> >> >no pressure head
> >> >it just moves the stuff around
> >> >probably a lot of power is not required
> >> >maybe 1-2 HP
> >> >Clive
> >> >> >But, isn't it inefficient to spin all those things at engine
RPM rather
> >> >> >than a constant RPM?  Seems like a pump/compressor that has
to work over
> >> >> >a 10:1 input speed ratio wouldn't be as efficient as one
designed to
> >> >> >work at a constant RPM.  Like A/C, and esp power steering. 
If those
> >> >> >were designed to run w/electric drive at constant RPM maybe
they'd be
> >> >> >more efficient.  Especially if you had a dual voltage
alternator and ran
> >> >> >the accessories at 100V 3phase.  maybe?
> >> >> >--steve
> >
> >--
> >Steve Ravet
> >ARM, INC
> >steve.ravet at arm.com
> >www.arm.com
> 
> 
> 
> 
> 

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