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70 Posts
Discussion Starter #1
Can this pump be used as a power steering pump if steering fluid is used instead of
methanol?

http://cgi.ebay.com/ebaymotors/Snow-Performance-Methanol-220-PSI-Pump-40220_W0QQcmdZViewItemQQhashZitem180169173899QQitemZ180169173899
or

http://tinyurl.com/ysanlu
Thanks
JJ
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Discussion Starter #2
First thing you should do, is research the minimum PSI rating of a standard
power steering unit, to see what type of pump will work. Go to a dealer or
a auto parts store and look at a the pump specifications for a steering
systems.

I found that my GM vehicle requires about 750 psi power steering oil
pressure to make it work. You will then need power steering hoses and
fittings that will take this pressure.

Electric power steering pumps have a pressure relief value that by passes
the fluid and is design to be fill under pressure at the low pressure side
inlet.

Roland


----- Original Message -----
From: <[email protected]>
To: <[email protected]>
Sent: Thursday, October 18, 2007 8:01 PM
Subject: [EVDL] power steering


>
>
> Can this pump be used as a power steering pump if steering fluid is used
> instead of
> methanol?
>
> http://cgi.ebay.com/ebaymotors/Snow-Performance-Methanol-220-PSI-Pump-40220_W0QQcmdZViewItemQQhashZitem180169173899QQitemZ180169173899
> or
>
> http://tinyurl.com/ysanlu
> Thanks
> JJ
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>

_______________________________________________
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70 Posts
Discussion Starter #3
Thanks Roland, that wasnt my doubt. The psi in various power steering modules range
from 750 to 1500 or so. This pump is only 230 psi and is meant for methanol, but is
inexpensive. I also dont want a very strong steering assist, only a small one and
hence 230 psi may do. However I dont know if this pump will take hydraulic fluid.
JJ

> On Thu, October 18, 2007 10:40 pm
EDT, Roland Wiench wrote:
>
>
> First thing you should do, is research the minimum PSI rating of a
standard
> power steering unit, to see what type of pump will work. Go to a
dealer or
> a auto parts store and look at a the pump specifications for a
steering
> systems.
>
> I found that my GM vehicle requires
about 750 psi power steering oil
> pressure to make it work. You will then
need power steering hoses and
> fittings that will take this pressure.
>
> Electric power steering pumps have a pressure relief value that by
passes
> the fluid and is design to be fill under pressure at the low
pressure side
> inlet.
>
> Roland
>
>
> ----- Original Message -----
> From:
> To:
> Sent:
Thursday, October 18, 2007 8:01 PM
> Subject: [EVDL] power steering
>
>
> >
> >
> > Can this pump be
used as a power steering pump if steering fluid is used
> > instead of
> > methanol?
> >
> >
http://cgi.ebay.com/ebaymotors/Snow-Performance-Methanol-220-PSI-Pump-40220_W0QQcmdZViewItemQQhashZitem180169173899QQitemZ180169173899
> > or
> >
> > http://tinyurl.com/ysanlu
>
> Thanks
> > JJ
> >
_______________________________________________
> > For subscription
options, see
> > http://lists.sjsu.edu/mailman/listinfo/ev
>
>
>
> _______________________________________________
>
For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>
>
>
_______________________________________________
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70 Posts
Discussion Starter #4
Don't the rack and pinion systems typically use considerably less pressure?
250psi comes to mind, as opposed to the 1000 ball park of the GM Saginaw
setup. I think my Ford Tempo uses a smaller pump with a remote reservoir
that may be fairly easy to run with an electric motor. Whether it would
have enough boost depends a lot on what type of steering gearbox you've got
I would think.

Marty

----- Original Message -----
From: <[email protected]>
To: <[email protected]>
Sent: Friday, October 19, 2007 9:28 AM
Subject: Re: [EVDL] power steering


>
>
> Thanks Roland, that wasnt my doubt. The psi in various power steering
> modules range
> from 750 to 1500 or so. This pump is only 230 psi and is meant for
> methanol, but is
> inexpensive. I also dont want a very strong steering assist, only a small
> one and
> hence 230 psi may do. However I dont know if this pump will take hydraulic
> fluid.
> JJ
>
>> On Thu, October 18, 2007 10:40 pm
> EDT, Roland Wiench wrote:
>>
>>
>> First thing you should do, is research the minimum PSI rating of a
> standard
>> power steering unit, to see what type of pump will work. Go to a
> dealer or
>> a auto parts store and look at a the pump specifications for a
> steering
>> systems.
>>
>> I found that my GM vehicle requires
> about 750 psi power steering oil
>> pressure to make it work. You will then
> need power steering hoses and
>> fittings that will take this pressure.
>>
>> Electric power steering pumps have a pressure relief value that by
> passes
>> the fluid and is design to be fill under pressure at the low
> pressure side
>> inlet.
>>
>> Roland
>>
>>
>> ----- Original Message -----
>> From:
>> To:
>> Sent:
> Thursday, October 18, 2007 8:01 PM
>> Subject: [EVDL] power steering
>>
>>
>> >
>> >
>> > Can this pump be
> used as a power steering pump if steering fluid is used
>> > instead of
>> > methanol?
>> >
>> >
> http://cgi.ebay.com/ebaymotors/Snow-Performance-Methanol-220-PSI-Pump-40220_W0QQcmdZViewItemQQhashZitem180169173899QQitemZ180169173899
>> > or
>> >
>> > http://tinyurl.com/ysanlu
>>
>> Thanks
>> > JJ
>> >
> _______________________________________________
>> > For subscription
> options, see
>> > http://lists.sjsu.edu/mailman/listinfo/ev
>>
>>
>>
>> _______________________________________________
>>
> For subscription options, see
>> http://lists.sjsu.edu/mailman/listinfo/ev
>>
>>
>>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>

_______________________________________________
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Discussion Starter #5
[EVDL] Power Steering

I'm just starting converting a 2001 Audi A4 Quattro to electric. I
pulled the old ICE out yesterday and I plan on keeping the AC and the
power steering functioning. The power steering pump puts out
1650-1800 psi per the service manual at dead-head (no-flow). I have
read that some people have used Toyota 12V power steering pumps in
their EVs. I also read that the power consumption is quite high, so I
have two questions for you all:

1. Does anyone have any experience with using an aftermarket off the
shelf hydraulic pump. I see some that are made for lift gates, and
others that are for power steering and trim in marine applications.
The marine type are about $500+ new, but used ones pop up on Ebay all
the time. They look perfect for the application and come in a compact
one piece assembly. The lift gate type may not be continuous duty.
Anyone have experience with either of the above?

2. To conserve energy I would like to have the power steering cut off
once I get up to speed. Ideally the transition should be smooth so
there is not a sudden noticeable change in control. Anyone have any
ideas on this?


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Discussion Starter #6
Re: [EVDL] Power Steering

Hello Roger,

I have a unit that I got from Randy at Canev . http://www.canev.com/ Randy
is a great guy and a pleasure to work with. It was a bit pricey but a
really nice unit. I would buy one again. I have a round rocker switch
mounted in the shift knob, just flick it on and off as needed.

I'm sure with the expert folks on the list they can lead you to some sort of
pressure activated sw if your inclinedd to go that way. But this set up
works just fine for me.

Jim


----- Original Message -----
From: "Roger Heuckeroth" <[email protected]>
To: <[email protected]>
Sent: Thursday, July 10, 2008 6:39 PM
Subject: [EVDL] Power Steering


> I'm just starting converting a 2001 Audi A4 Quattro to electric. I
> pulled the old ICE out yesterday and I plan on keeping the AC and the
> power steering functioning. The power steering pump puts out
> 1650-1800 psi per the service manual at dead-head (no-flow). I have
> read that some people have used Toyota 12V power steering pumps in
> their EVs. I also read that the power consumption is quite high, so I
> have two questions for you all:
>
> 1. Does anyone have any experience with using an aftermarket off the
> shelf hydraulic pump. I see some that are made for lift gates, and
> others that are for power steering and trim in marine applications.
> The marine type are about $500+ new, but used ones pop up on Ebay all
> the time. They look perfect for the application and come in a compact
> one piece assembly. The lift gate type may not be continuous duty.
> Anyone have experience with either of the above?
>
> 2. To conserve energy I would like to have the power steering cut off
> once I get up to speed. Ideally the transition should be smooth so
> there is not a sudden noticeable change in control. Anyone have any
> ideas on this?
>
>
> _______________________________________________
> For general EVDL support, see http://evdl.org/help/
> For subscription options, see http://lists.sjsu.edu/mailman/listinfo/ev
>


_______________________________________________
For general EVDL support, see http://evdl.org/help/
For subscription options, see http://lists.sjsu.edu/mailman/listinfo/ev
 

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Discussion Starter #7
Re: [EVDL] Power Steering

On Thu, 10 Jul 2008 19:39:34 -0400, Roger Heuckeroth <[email protected]>
wrote:

>I'm just starting converting a 2001 Audi A4 Quattro to electric. I
>pulled the old ICE out yesterday and I plan on keeping the AC and the
>power steering functioning. The power steering pump puts out
>1650-1800 psi per the service manual at dead-head (no-flow). I have
>read that some people have used Toyota 12V power steering pumps in
>their EVs. I also read that the power consumption is quite high, so I
>have two questions for you all:

Unless Audi is doing something different from every other car maker, the
hydraulic circuit is "open spool". That is, there is no pressure other than
frictional losses in the system until power assist is called for. This is
easy enough to detect. If the pressure hose stiffens and moves when the wheel
is turned then it is open-spool.

The hydraulic pump under open spool conditions consumes almost no power. Just
frictional losses.

>
>1. Does anyone have any experience with using an aftermarket off the
>shelf hydraulic pump. I see some that are made for lift gates, and
>others that are for power steering and trim in marine applications.
>The marine type are about $500+ new, but used ones pop up on Ebay all
>the time. They look perfect for the application and come in a compact
>one piece assembly. The lift gate type may not be continuous duty.
>Anyone have experience with either of the above?

Almost all of those are highly intermittent duty rated. If it has what looks
like a car starter motor then it's intermittent. I'm not sure that I've ever
seen a continuous duty 12 volt hydraulic pump.

If you don't want to drive the stock PS pump with an aux motor (my approach)
then you might consider a fork lift pump. At least it's continuous duty
rated. You might even be able to find a 96 volt one that could be made to
work on the usual pack voltages.

>
>2. To conserve energy I would like to have the power steering cut off
>once I get up to speed. Ideally the transition should be smooth so
>there is not a sudden noticeable change in control. Anyone have any
>ideas on this?

This is problematic and it probably won't save enough energy to be worthwhile.
The problem is, detecting when there is demand for power assist. Since there
is no pressure in the system until assist is requested by the spool valve, a
simple pressure switch or other similar approach would not work.

Going on my experiences with breaking belts on conventional cars, I can't
imagine being able to make a seamless transition without some serious control
electronics.

The pump's power input demand is proportional to the assist requested at any
instant. Since the assist is so low at speed, the pump will consume such a
little bit of energy that I doubt that it will be worthwhile to stop it.

To scale this problem, the heavy duty truck-type power steering on the AVS bus
is powered by a 1 hp PM motor. That means that at FULL ASSIST, the system
required 1 hp or less. The pump is MUCH larger than a car pump.

If you want to see how much idling power the pump requires, connect the outlet
to the inlet of the pump, put it on your bench, strap it to any available
motor and spin it up. Measure the increase in power over the motor operating
unloaded. I bet that it'll only be a couple hundred watts max and probably
less.

One thing to look at is whether the pump has an outlet check valve or not.
Many do. This valve presents a hundred PSI or so of backpressure to the pump.
Removing that valve (I think that it's there to keep the pump rollers from
rattling under no load) will reduce the idling load considerably.

One other comment. I used a randomly selected junkyard pump (GMish) to power
my manual hydraulic press. It's driven at about a 2:1 stepdown ratio V belt
by a 1/4 hp 1750 RPM AC motor. The motor has never given any indication of
overload. It's slow but I have patience :) I could probably drive the pump
1:1 and speed things up a bit.

John

--
John De Armond
See my website for my current email address
http://www.neon-john.com
http://www.johndearmond.com <-- best little blog on the net!
Tellico Plains, Occupied TN
If the letters PhD appear after a person's name, that person will
remain outdoors even after it's started raining.


_______________________________________________
For general EVDL support, see http://evdl.org/help/
For subscription options, see http://lists.sjsu.edu/mailman/listinfo/ev
 

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Discussion Starter #8
Re: [EVDL] Power Steering

The unit on the CANEV website looks just like the marine models I was
looking at. That is probably where its from.

Jim & Angie wrote:

> Hello Roger,
>
> I have a unit that I got from Randy at Canev . http://
> www.canev.com/ Randy
> is a great guy and a pleasure to work with. It was a bit pricey but a
> really nice unit. I would buy one again. I have a round rocker switch
> mounted in the shift knob, just flick it on and off as needed.
>
> I'm sure with the expert folks on the list they can lead you to some
> sort of
> pressure activated sw if your inclinedd to go that way. But this
> set up
> works just fine for me.
>
> Jim
>
>
> ----- Original Message -----
> From: "Roger Heuckeroth" <[email protected]>
> To: <[email protected]>
> Sent: Thursday, July 10, 2008 6:39 PM
> Subject: [EVDL] Power Steering
>
>
>> I'm just starting converting a 2001 Audi A4 Quattro to electric. I
>> pulled the old ICE out yesterday and I plan on keeping the AC and the
>> power steering functioning. The power steering pump puts out
>> 1650-1800 psi per the service manual at dead-head (no-flow). I have
>> read that some people have used Toyota 12V power steering pumps in
>> their EVs. I also read that the power consumption is quite high,
>> so I
>> have two questions for you all:
>>
>> 1. Does anyone have any experience with using an aftermarket off the
>> shelf hydraulic pump. I see some that are made for lift gates, and
>> others that are for power steering and trim in marine applications.
>> The marine type are about $500+ new, but used ones pop up on Ebay all
>> the time. They look perfect for the application and come in a
>> compact
>> one piece assembly. The lift gate type may not be continuous duty.
>> Anyone have experience with either of the above?
>>
>> 2. To conserve energy I would like to have the power steering cut
>> off
>> once I get up to speed. Ideally the transition should be smooth so
>> there is not a sudden noticeable change in control. Anyone have any
>> ideas on this?
>>
>>
>> _______________________________________________
>> For general EVDL support, see http://evdl.org/help/
>> For subscription options, see http://lists.sjsu.edu/mailman/listinfo/ev
>>
>
>
> _______________________________________________
> For general EVDL support, see http://evdl.org/help/
> For subscription options, see http://lists.sjsu.edu/mailman/listinfo/
> ev


_______________________________________________
For general EVDL support, see http://evdl.org/help/
For subscription options, see http://lists.sjsu.edu/mailman/listinfo/ev
 

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Discussion Starter #9
Re: [EVDL] Power Steering

That interesting that the pump is only 1/4 HP, or so. That was what I
initially estimated, but I read other things on line that suggested it
was 2-5 HP. One reference actually suggested that removing the PS
pump gained someone 26 HP on the dyno. Maybe at 6000 RPM that might
be true.

If it was 1/4 HP then at 12 V it should draw less than 20 Amps. The
Toyota MR2 pump requires a 75A fuse. That would be closed to 1 HP.

Neon John wrote:

> On Thu, 10 Jul 2008 19:39:34 -0400, Roger Heuckeroth <[email protected]
> >
> wrote:
>
>> I'm just starting converting a 2001 Audi A4 Quattro to electric. I
>> pulled the old ICE out yesterday and I plan on keeping the AC and the
>> power steering functioning. The power steering pump puts out
>> 1650-1800 psi per the service manual at dead-head (no-flow). I have
>> read that some people have used Toyota 12V power steering pumps in
>> their EVs. I also read that the power consumption is quite high,
>> so I
>> have two questions for you all:
>
> Unless Audi is doing something different from every other car maker,
> the
> hydraulic circuit is "open spool". That is, there is no pressure
> other than
> frictional losses in the system until power assist is called for.
> This is
> easy enough to detect. If the pressure hose stiffens and moves when
> the wheel
> is turned then it is open-spool.
>
> The hydraulic pump under open spool conditions consumes almost no
> power. Just
> frictional losses.
>
>>
>> 1. Does anyone have any experience with using an aftermarket off the
>> shelf hydraulic pump. I see some that are made for lift gates, and
>> others that are for power steering and trim in marine applications.
>> The marine type are about $500+ new, but used ones pop up on Ebay all
>> the time. They look perfect for the application and come in a
>> compact
>> one piece assembly. The lift gate type may not be continuous duty.
>> Anyone have experience with either of the above?
>
> Almost all of those are highly intermittent duty rated. If it has
> what looks
> like a car starter motor then it's intermittent. I'm not sure that
> I've ever
> seen a continuous duty 12 volt hydraulic pump.
>
> If you don't want to drive the stock PS pump with an aux motor (my
> approach)
> then you might consider a fork lift pump. At least it's continuous
> duty
> rated. You might even be able to find a 96 volt one that could be
> made to
> work on the usual pack voltages.
>
>>
>> 2. To conserve energy I would like to have the power steering cut
>> off
>> once I get up to speed. Ideally the transition should be smooth so
>> there is not a sudden noticeable change in control. Anyone have any
>> ideas on this?
>
> This is problematic and it probably won't save enough energy to be
> worthwhile.
> The problem is, detecting when there is demand for power assist.
> Since there
> is no pressure in the system until assist is requested by the spool
> valve, a
> simple pressure switch or other similar approach would not work.
>
> Going on my experiences with breaking belts on conventional cars, I
> can't
> imagine being able to make a seamless transition without some
> serious control
> electronics.
>
> The pump's power input demand is proportional to the assist
> requested at any
> instant. Since the assist is so low at speed, the pump will consume
> such a
> little bit of energy that I doubt that it will be worthwhile to stop
> it.
>
> To scale this problem, the heavy duty truck-type power steering on
> the AVS bus
> is powered by a 1 hp PM motor. That means that at FULL ASSIST, the
> system
> required 1 hp or less. The pump is MUCH larger than a car pump.
>
> If you want to see how much idling power the pump requires, connect
> the outlet
> to the inlet of the pump, put it on your bench, strap it to any
> available
> motor and spin it up. Measure the increase in power over the motor
> operating
> unloaded. I bet that it'll only be a couple hundred watts max and
> probably
> less.
>
> One thing to look at is whether the pump has an outlet check valve
> or not.
> Many do. This valve presents a hundred PSI or so of backpressure to
> the pump.
> Removing that valve (I think that it's there to keep the pump
> rollers from
> rattling under no load) will reduce the idling load considerably.
>
> One other comment. I used a randomly selected junkyard pump (GMish)
> to power
> my manual hydraulic press. It's driven at about a 2:1 stepdown
> ratio V belt
> by a 1/4 hp 1750 RPM AC motor. The motor has never given any
> indication of
> overload. It's slow but I have patience :) I could probably drive
> the pump
> 1:1 and speed things up a bit.
>
> John
>
> --
> John De Armond
> See my website for my current email address
> http://www.neon-john.com
> http://www.johndearmond.com <-- best little blog on the net!
> Tellico Plains, Occupied TN
> If the letters PhD appear after a person's name, that person will
> remain outdoors even after it's started raining.
>
>
> _______________________________________________
> For general EVDL support, see http://evdl.org/help/
> For subscription options, see http://lists.sjsu.edu/mailman/listinfo/
> ev


_______________________________________________
For general EVDL support, see http://evdl.org/help/
For subscription options, see http://lists.sjsu.edu/mailman/listinfo/ev
 

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Discussion Starter #10
Re: [EVDL] Power Steering

I have been running the CanEV pump for 18 months and the steering is smooth
as glass on my 77 El Camino. Even without the pump on, my steering is still
on the soft side because of the high pressure tires.

I have banks of 12 volt and amp gages monitoring all my 12 volt systems, and
I have never seen power steering ampere go above 20 amps, it normally stays
at about 16 amps when turning on a 90 degree street corner.

Randy at CanEV said it is best to keep it on all the time, because it's
hardly any load when you are going in a straight line. If you install a
position control unit on the steering shaft so it will shut down while you
are driving in a straight line and have it activated at a certain turn
angle, then every time you may turn the steering shaft back and forth, you
are going to short cycle, causing a higher ampere surge where the average
ampere is higher, then if you left it running.

I have all the positional steering shaft control unit plus even a time delay
unit, so as not to short cycle, but I found it was not needed.

Roland


----- Original Message -----
From: "Roger Heuckeroth" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Friday, July 11, 2008 7:45 AM
Subject: Re: [EVDL] Power Steering


> That interesting that the pump is only 1/4 HP, or so. That was what I
> initially estimated, but I read other things on line that suggested it
> was 2-5 HP. One reference actually suggested that removing the PS
> pump gained someone 26 HP on the dyno. Maybe at 6000 RPM that might
> be true.
>
> If it was 1/4 HP then at 12 V it should draw less than 20 Amps. The
> Toyota MR2 pump requires a 75A fuse. That would be closed to 1 HP.
>
>
Neon John wrote:
>
> > On Thu, 10 Jul 2008 19:39:34 -0400, Roger Heuckeroth
> > <[email protected]
> > >
> > wrote:
> >
> >> I'm just starting converting a 2001 Audi A4 Quattro to electric. I
> >> pulled the old ICE out yesterday and I plan on keeping the AC and the
> >> power steering functioning. The power steering pump puts out
> >> 1650-1800 psi per the service manual at dead-head (no-flow). I have
> >> read that some people have used Toyota 12V power steering pumps in
> >> their EVs. I also read that the power consumption is quite high,
> >> so I
> >> have two questions for you all:
> >
> > Unless Audi is doing something different from every other car maker,
> > the
> > hydraulic circuit is "open spool". That is, there is no pressure
> > other than
> > frictional losses in the system until power assist is called for.
> > This is
> > easy enough to detect. If the pressure hose stiffens and moves when
> > the wheel
> > is turned then it is open-spool.
> >
> > The hydraulic pump under open spool conditions consumes almost no
> > power. Just
> > frictional losses.
> >
> >>
> >> 1. Does anyone have any experience with using an aftermarket off the
> >> shelf hydraulic pump. I see some that are made for lift gates, and
> >> others that are for power steering and trim in marine applications.
> >> The marine type are about $500+ new, but used ones pop up on Ebay all
> >> the time. They look perfect for the application and come in a
> >> compact
> >> one piece assembly. The lift gate type may not be continuous duty.
> >> Anyone have experience with either of the above?
> >
> > Almost all of those are highly intermittent duty rated. If it has
> > what looks
> > like a car starter motor then it's intermittent. I'm not sure that
> > I've ever
> > seen a continuous duty 12 volt hydraulic pump.
> >
> > If you don't want to drive the stock PS pump with an aux motor (my
> > approach)
> > then you might consider a fork lift pump. At least it's continuous
> > duty
> > rated. You might even be able to find a 96 volt one that could be
> > made to
> > work on the usual pack voltages.
> >
> >>
> >> 2. To conserve energy I would like to have the power steering cut
> >> off
> >> once I get up to speed. Ideally the transition should be smooth so
> >> there is not a sudden noticeable change in control. Anyone have any
> >> ideas on this?
> >
> > This is problematic and it probably won't save enough energy to be
> > worthwhile.
> > The problem is, detecting when there is demand for power assist.
> > Since there
> > is no pressure in the system until assist is requested by the spool
> > valve, a
> > simple pressure switch or other similar approach would not work.
> >
> > Going on my experiences with breaking belts on conventional cars, I
> > can't
> > imagine being able to make a seamless transition without some
> > serious control
> > electronics.
> >
> > The pump's power input demand is proportional to the assist
> > requested at any
> > instant. Since the assist is so low at speed, the pump will consume
> > such a
> > little bit of energy that I doubt that it will be worthwhile to stop
> > it.
> >
> > To scale this problem, the heavy duty truck-type power steering on
> > the AVS bus
> > is powered by a 1 hp PM motor. That means that at FULL ASSIST, the
> > system
> > required 1 hp or less. The pump is MUCH larger than a car pump.
> >
> > If you want to see how much idling power the pump requires, connect
> > the outlet
> > to the inlet of the pump, put it on your bench, strap it to any
> > available
> > motor and spin it up. Measure the increase in power over the motor
> > operating
> > unloaded. I bet that it'll only be a couple hundred watts max and
> > probably
> > less.
> >
> > One thing to look at is whether the pump has an outlet check valve
> > or not.
> > Many do. This valve presents a hundred PSI or so of backpressure to
> > the pump.
> > Removing that valve (I think that it's there to keep the pump
> > rollers from
> > rattling under no load) will reduce the idling load considerably.
> >
> > One other comment. I used a randomly selected junkyard pump (GMish)
> > to power
> > my manual hydraulic press. It's driven at about a 2:1 stepdown
> > ratio V belt
> > by a 1/4 hp 1750 RPM AC motor. The motor has never given any
> > indication of
> > overload. It's slow but I have patience :) I could probably drive
> > the pump
> > 1:1 and speed things up a bit.
> >
> > John
> >
> > --
> > John De Armond
> > See my website for my current email address
> > http://www.neon-john.com
> > http://www.johndearmond.com <-- best little blog on the net!
> > Tellico Plains, Occupied TN
> > If the letters PhD appear after a person's name, that person will
> > remain outdoors even after it's started raining.
> >
> >
> > _______________________________________________
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> > ev
>
>
> _______________________________________________
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>
>


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Discussion Starter #11
Re: [EVDL] Power Steering

On Fri, 11 Jul 2008 09:45:15 -0400, Roger Heuckeroth <[email protected]>
wrote:

>That interesting that the pump is only 1/4 HP, or so. That was what I
>initially estimated, but I read other things on line that suggested it
>was 2-5 HP. One reference actually suggested that removing the PS
>pump gained someone 26 HP on the dyno. Maybe at 6000 RPM that might
>be true.

One can read the silliest things on the net :) Based on many hours spent at
the console of a dyno, I can describe a scenario where that would seem to be
the case but wasn't.

>
>If it was 1/4 HP then at 12 V it should draw less than 20 Amps. The
>Toyota MR2 pump requires a 75A fuse. That would be closed to 1 HP.

Remember that HP is simply a measure of the rate of doing work. My 1/4hp
motor gets the job done because my press does its work quite slowly. The pump
itself uses practically no power, only the small frictional losses. It's just
a work translator. If you need to do work rapidly (turn the steering wheel
rapidly while stationary) then there must be more work - HP - input to the
pump.

There are two considerations. One, how fast the work must be done, usually a
consideration at very low to stationary speed and during emergency maneuver.
Two, what maximum steering wheel velocity must be supported. That is a
function of fluid volume flow.

To separate the two concepts, consider a limiting condition - the car is up on
jacks and you spin the steering wheel rapidly. If there is to be any assist,
the pump must supply the necessary volume to keep up with the actuator inside
the steering box. There is little to no resistance to the movement so the
pressure will not be very high. High volume, low pressure.

Now take the opposite situation. The car is stationary. This is the highest
tire friction situation. Even if you turn the wheel slowly, the amount of
force necessary to turn the tires is high and therefore the pump must supply
high pressure, albeit at low flow.

Both of these limiting conditions are low HP situations. The first is high
flow, low pressure and the second is high pressure low flow.

Now consider the third limiting condition, turning the wheel rapidly with the
car stationary. Now the pump must supply both high flow and high pressure.
This is probably the highest HP situation.

In fact, it's not unusual for a power steering system not to be able to handle
this situation, particularly at engine idle. As you turn the wheel faster and
faster, a point is reached where the pump is supplying the maximum flow it is
capable of. Trying to turn the wheel any faster results in great resistance,
as there is no longer any assist. Revving the engine - spinning the pump
faster so that it can supply more volume - remedies the problem.

A similar situation can arise at speed during an emergency or otherwise rapid
maneuver if the pump isn't driven fast enough. As you yank the wheel,
suddenly it feels like a brake has been applied to the steering shaft. The
power assist unit's flow demand has exceeded the pump's capability and
suddenly there is no assist. This can be quite disconcerting when one is,
say, controlling a skid or swerving to miss a road obstacle.

Where I've seen this situation most often is where an amateur hotrodder
installs a "power pulley", a smaller diameter crankshaft pulley, believing the
hype that turning the accessories slower will somehow unleash untold
horsepower. It does free up a tiny bit of power but at the expense of this
steering effect, engine overheating from lack of coolant flow and an
alternator that can't keep up with electricity demands at idle and just above
- such as at cruising speeds.

To electrically drive the pump properly, my starting place would be to
duplicate the IC engine drive. Figure out a typical cruising engine RPM, the
work back through the pulley ratios and determine how fast the PS pump is
being spun. The underlying assumption is that the OEM is spinning the pump
fast enough to handle any anticipated emergency maneuver.

The power demand when supplying an emergency maneuver will be quite high,
perhaps one of the highest. Turning a nearly stationary tire will require a
bit more force (pressure) but not necessarily more speed (volume). It is
acceptable to hit a steering wheel speed limit when turning the wheel while
parking but it isn't when trying to miss that debris in the road or dodge the
guy who just pulled out in front of you.

What that means is that though the average power demand will be low, the
driving motor has to be capable of supplying the high peak power necessary
during these maneuver situations. That's why the Toyota pump is fused at such
a high amperage, even though the idle draw is a fraction of the peak.

A PM (as on the AVS bus) or a series motor can do that as long as the
electrical supply can hold up. It may be a problem if you're running a DC/DC
converter with no aux battery. AVS solved the problem by using a high voltage
motor and running it at (near) the pack voltage. I haven't gotten deeply
enough into their system yet to know whether the motor tapped the traction
battery directly or if there was a voltage regulator involved.

When you're stationary or cruising along in a straight line, barely moving the
wheel, the power demand will be low, I'd guess significantly under 200 watts.
However, yank the wheel hard and fast and the power demand may peak at several
HP. Obviously the peak won't last long, probably not even a second, so a
flywheel on the motor might help a lot.

The easy way to do this is to copy what someone else has done. It might not
be the most energy-efficient method, though. This is an area, along with the
AC compressor drive, where I'm going to be experimenting fairly intensely over
the next few months. I want to have both system designs completed BEFORE I
start the actual conversion so that the conversion will be little more than
bolting together pre-prepared assemblies.

If you want or need to get ahead of me then we can work together on the
testing protocol.

John

--
John De Armond
See my website for my current email address
http://www.neon-john.com
http://www.johndearmond.com <-- best little blog on the net!
Tellico Plains, Occupied TN
Unable to locate Coffee -- Operator Halted!


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Discussion Starter #12
[EVDL] Power steering

G'day All

Having acquired a donor (1991 Honda Civic hatchback, Australian spec) that
has power steering, I'm looking to keep the power steering as it *looks*
like less work and cost to keep it than to change it (due to the 'bits'
already on hand).

Here is the theory:

I already have a permanent magnet motor, 72V 0.75kW/15 mins. Use that to
drive the existing PS Pump under PWM control.

I will be pulling the steering column anyway (to get at the heater) so
whilst it is out putting a small toothed-belt pulley on the column should
be no biggie(?). Belt drive a rotary encoder from the steering column.

The encoder will provide a pulse rate proportional to the speed that the
wheel is being turned. No biggie to make a piece of electronics to convert
the pulse rate into a PWM chopper transistor drive to drive the PS drive
motor proportional to wheel movement - so the more the wheel is turned, the
more PS assist is provided.

The electronics would contain a frequency to voltage converter (IC), use
resistor/capacitor/diode time constants to give it short ramp up time and
longer decay time. Turn the voltage into a PWM (compare the voltage to a
sawtooth voltage of the operating frequency). Analogue threshold/gain makes
sure that the PWM on-time does not apply too much voltage to the motor).
Use an optocoupler to get over from vehicle voltage reference to pack
reference and drive a single large FET (I have plenty of IRFP460 on hand)
and a suitable diode.

What opinions?

TIA

Regards

[Technik] James

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Discussion Starter #13
Re: [EVDL] Power steering

On Sun, 2009-03-29 at 09:40 +1000, James Massey wrote:

> I will be pulling the steering column anyway (to get at the heater) so
> whilst it is out putting a small toothed-belt pulley on the column should
> be no biggie(?). Belt drive a rotary encoder from the steering column.

I can't comment on the rest of your plan (other than it sounds
complicated), but this is designed for measuring steering position:
http://www.race-technology.com/string_pot_steering_2_59.html


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Discussion Starter #14
Re: [EVDL] Power steering

At 09:32 AM 29/03/09, Tom wrote:
>On Sun, 2009-03-29 at 09:40 +1000, James Massey wrote:
>
> > I will be pulling the steering column anyway (to get at the heater) so
> > whilst it is out putting a small toothed-belt pulley on the column should
> > be no biggie(?). Belt drive a rotary encoder from the steering column.
>
>I can't comment on the rest of your plan (other than it sounds
>complicated), but this is designed for measuring steering position:
>http://www.race-technology.com/string_pot_steering_2_59.html

G'day Tom, All

That sensor is a position sensor, I don't need to know where it is, just
how much movement is being applied. A pulse encoder does this just fine.

Fleabay suitable encoder:
ENCODER ROTARY, NEW, MADE BRITISH ENCODER PRODUCTS Item number: 160322655747

A hollow shaft encoder may be able to be mounted directly onto the steering
shaft (suitably bushed) and not need the drive belt. Depends on the
availability of a hollow shaft encoder and the diameter of the steering
shaft. Here is a random web hit for a hollow shaft encoder:
http://www.photocraftencoders.com/HRL.htm

As to the rest of the plan, complicated depends on what you do for a
living. That sort of stuff is 'just do' for me, so not a complicated thing
for me, your results may vary.

Regards

[Technik] James

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