EV Digest 6408
Topics covered in this issue include:
1) Re: Brake Pressure Multiplier?
by "FRED JEANETTE MERTENS" <[EMAIL PROTECTED]>
2) Re: Brake Pressure Multiplier?
by "FRED JEANETTE MERTENS" <[EMAIL PROTECTED]>
3) Re: Hi all
by "FRED JEANETTE MERTENS" <[EMAIL PROTECTED]>
4) Re: Brake Pressure Multiplier?
by "Phil Marino" <[EMAIL PROTECTED]>
5) Re: Brake Pressure Multiplier?
by "Peter VanDerWal" <[EMAIL PROTECTED]>
6) Re: Brake Pressure Multiplier?
by Nick Austin <[EMAIL PROTECTED]>
7) White lists
by "Peter VanDerWal" <[EMAIL PROTECTED]>
8) RE: Brake Pressure Multiplier?
by Cor van de Water <[EMAIL PROTECTED]>
9) Vacuum pump running constantly
by "Deanne Mott" <[EMAIL PROTECTED]>
10) Re: Brake Pressure Multiplier?
by Doug Weathers <[EMAIL PROTECTED]>
11) RE: Vacuum pump running constantly
by Cor van de Water <[EMAIL PROTECTED]>
12) Re: Vacuum pump running constantly
by David Brandt <[EMAIL PROTECTED]>
13) Re: Personal Electric Transport
by "David O'Neel" <[EMAIL PROTECTED]>
14) RE: Brake Pressure Multiplier?
by Cor van de Water <[EMAIL PROTECTED]>
15) Re: Brake Pressure Multiplier?
by David Dymaxion <[EMAIL PROTECTED]>
16) Re: Brake Pressure Multiplier?
by Lee Hart <[EMAIL PROTECTED]>
17) Re: Vacuum pump running constantly
by "Peter VanDerWal" <[EMAIL PROTECTED]>
18) Re: Vacuum pump running constantly
by "Deanne Mott" <[EMAIL PROTECTED]>
19) RE: Vacuum pump running constantly
by Cor van de Water <[EMAIL PROTECTED]>
--- Begin Message ---
thank you it IS a lot clearer ....now....
----- Original Message -----
From: Cor van de Water<mailto:[EMAIL PROTECTED]>
To: [email protected]<mailto:[email protected]>
Sent: Monday, February 12, 2007 1:27 AM
Subject: RE: Brake Pressure Multiplier?
Fred,
Paul already provided the answer and the reference to the 914
forum has it in even more detail:
- if your brake cylinder diameter increased with the disk brakes,
then you have more stopping power (at the cost of larger
pedal travel)
- if your disk brake cylinders are the same diameter as the drums
then they apply the same force to the brakes. It now depends on
the pad material if you have higher friction or not.
- if the disk brake cylinders have smaller diameter than the drums
then the force on the brakes is now lower, so your stopping
power has likely deteriorated, though you should have a very
firm feeling pedal (little travel). The BPM can help you to
increase force on the brakes at the cost of larger pedal travel.
This BPM work in the same way as a pulley system can help you to
lift 2,000 lbs of weight with only 100 lbs of force, by making the
travel of the chain twenty times larger than the lift provided on
the 2,000 lbs object. The power reduces, the energy stays the same
(force x distance) just like using different gears.
Hope this clarifies,
Cor van de Water
Systems Architect
Proxim Wireless Corporation http://www.proxim.com<http://www.proxim.com/>
Email: [EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]> Private:
http://www.cvandewater.com<http://www.cvandewater.com/>
Skype: cor_van_de_water IM: [EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]>
Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
Fax: +1 408 731 3675 eFAX: +31-87-784-1130
Second Life:
www.secondlife.com/?u=3b42cb3f4ae249319edb487991c30acb<http://www.secondlife.com/?u=3b42cb3f4ae249319edb487991c30acb>
-----Original Message-----
From: [EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]> [mailto:[EMAIL PROTECTED]
Behalf Of FRED JEANETTE MERTENS
Sent: Sunday, February 11, 2007 4:17 PM
To: [email protected]<mailto:[email protected]>
Subject: Re: Brake Pressure Multiplier?
paul I just change the drum brakes out for 4 wheel disc with e brake so I
would have better stopping power . soo what you seem to hint at is that is
probably the best I can do ???????
----- Original Message -----
From: Paul G.<mailto:[EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]>>
To: [email protected]<mailto:[email protected]<mailto:[EMAIL
PROTECTED]:[email protected]>>
Sent: Sunday, February 11, 2007 5:49 PM
Subject: Re: Brake Pressure Multiplier?
On Feb 11, 2007, at 1:22 PM, Ryan Stotts wrote:
> Is this the answer to our power brakes(i.e. no vacuum booster)?
>
>
http://ecihotrodbrakes.com/brake_pressure_multiplier.html<http://ecihotrodbr<http://ecihotrodbrakes.com/brake_pressure_multiplier.html%3Chttp://ecihotrodbr>
akes.com/brake_pressure_multiplier.html>
No, this is more of an answer for those who fail to correctly size
their wheel cylinders to their master cylinder. It could be helpful
when mixing parts in a street rod. It increases pedal travel by driving
a larger piston, then uses a smaller piston to drive the brakes its
connected to. The same effect could be obtained by installing larger
diameter wheel cylinders.
With duel circuit brakes you need to be careful when increase brake
leverage with either a device like this, larger wheel cylinders, or
relocating the pivot point of the brake pedal. You need to make sure
that in the event that either 1/2 of the brakes fail the other 1/2 will
be fully applied before the brake pedal reaches the floor. (otherwise
having duel circuit brakes does nothing for you)
Paul "neon" G.
--- End Message ---
--- Begin Message ---
cor and phil if this is true would? will? this work then ? hook up a
variable pressure transducer that change the out put so as brake pedal travel
increases the the transducer varies the field of a generator (or a
regenerative system ) so the amount of regeneration increases as the pedal
travel increases giving more regen braking and keeping the wear / life on the
brake system to last longer ?
----- Original Message -----
From: Phil Marino<mailto:[EMAIL PROTECTED]>
To: [email protected]<mailto:[email protected]>
Sent: Monday, February 12, 2007 10:41 AM
Subject: RE: Brake Pressure Multiplier?
Cor-
I think you missed the main feature of this particular device.
They claim that, by using stepped cylinders, it provides a variable-leverage
system . They don't spell it out in this much detail, but my assumption is
that it behaves as a typical system for the first part of it's travel, and
then the ratio changes, so that, as you get to the "hard" part of the brake
pedal's travel, it supplies more hydraulic pressure in exchange for more
pedal motion - but just at the lower part of its travel.
If this is true, then it could do what it claims - supply substantially more
brake force at the end of pedal travel- where you need it - with only a
little more total pedal travel than a conventional system.
So, your analogy is good, in that it works similarly to a pulley system (
like any hydraulic system) .
But, in this case it works like a pulley system whose configuration ( and
mechanical advantage) changes partway through its range of motion.
Phil
>
>Paul already provided the answer and the reference to the 914
>forum has it in even more detail:
>- if your brake cylinder diameter increased with the disk brakes,
> then you have more stopping power (at the cost of larger
> pedal travel)
>- if your disk brake cylinders are the same diameter as the drums
> then they apply the same force to the brakes. It now depends on
> the pad material if you have higher friction or not.
>- if the disk brake cylinders have smaller diameter than the drums
> then the force on the brakes is now lower, so your stopping
> power has likely deteriorated, though you should have a very
> firm feeling pedal (little travel). The BPM can help you to
> increase force on the brakes at the cost of larger pedal travel.
>
>This BPM work in the same way as a pulley system can help you to
>lift 2,000 lbs of weight with only 100 lbs of force, by making the
>travel of the chain twenty times larger than the lift provided on
>the 2,000 lbs object. The power reduces, the energy stays the same
>(force x distance) just like using different gears.
>
>Hope this clarifies,
>
>Cor van de Water
> On Feb 11, 2007, at 1:22 PM, Ryan Stotts wrote:
>
> > Is this the answer to our power brakes(i.e. no vacuum booster)?
> >
> >
>http://ecihotrodbrakes.com/brake_pressure_multiplier.html<http://ecihotrodbr<http://ecihotrodbr/>
>akes.com/brake_pressure_multiplier.html>
>
_________________________________________________________________
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--- End Message ---
--- Begin Message ---
darn good point lets do both!!!
----- Original Message -----
From: sushrut patgaonkar<mailto:[EMAIL PROTECTED]>
To: [email protected]<mailto:[email protected]>
Sent: Monday, February 12, 2007 10:20 AM
Subject: Hi all
Hello Everyone,
I was reading Robert Zubrins article on energy and it seems that our planets
energy problems are more political than technological. We need more of
peoples politicians than scientists to make our troubles go away,My country
recently closed it biodiesel plants as they were not competitive enough.
Developed countries and global super powers must show the way to the world
in terms of energy independance and sustainable energy futures
What is stopping America from using biofuels for non automotive applications
like house heating and small scale industries?
What can a group of dedicated people not achieve ?
Instead of converting cars to electrics we should convert politicians to
green thinking. Whatever you may argue they are the decision makers so
changing them will be of more impact than changing cars to electricity.
I know it is messy but then what isnt,
But also converting cars to electricity is more easier , more fun and less
complicated than converting politicians
But then lets hope
Sushrut
--- End Message ---
--- Begin Message ---
From: "FRED JEANETTE MERTENS" <[EMAIL PROTECTED]>
Reply-To: [email protected]
To: <[email protected]>
Subject: Re: Brake Pressure Multiplier?
Date: Mon, 12 Feb 2007 17:55:37 -0600
cor and phil if this is true would? will? this work then ? hook up a
variable pressure transducer that change the out put so as brake pedal
travel increases the the transducer varies the field of a generator (or a
regenerative system ) so the amount of regeneration increases as the pedal
travel increases giving more regen braking and keeping the wear / life on
the brake system to last longer ?
----- Original Message -----
I t seems to me that you could use a pressure transducer ( I'm not sure if
you mean something different by "variable pressure transducer" ) to monitor
brake system hydraulic pressure and act as an input signal to control
regenerative braking.
You don't particularly need a stepped-cylinder system to do this though,
Also, a set of brake pads should last many tens of thousands of miles even
without regen ( and, especially if you try to drive efficiently) and are
pretty cheap anyway. So, I would not bother with this if your main purpose
is to save on brake pads.
And, I would hesitate before modifying the brake system in any way ( even by
adding a pressure sensor). If the sensor failed by blowing out or leaking,
you would instantly have no brakes. That would be dangerous for you and
anyone else on the road with you.
Phil
_________________________________________________________________
Check out all that glitters with the MSN Entertainment Guide to the Academy
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--- End Message ---
--- Begin Message ---
Hmm, interesting.
Still, someone correct me if I'm wrong. but it seems to me that untill you
experience brake fade, drum brakes will like provide more stopping power
per pedal effort on un-assisted brakes (due to the self-actuating
feature).
I pretty sure that sports cars went to disc brakes (even un-assisted disc
brakes) because racing involves LOTS of slowing down and speeding up.
The kind of driving that is NOT typical for most EV commuters. I'm
thinking that drum brakes might actually be better than discs in a
commuter type EV.
>>Were you experiencing brake fade due to long down hills or frequent stops
>>from high speed?
>>
>>THe big advantage of disc brakes is that they can shed heat faster and
>>avoid fading (to some extent).
>
> That certainly is one advantage, but it's a little more complicated than
> that.
>
> Drum brakes are generally " self-actuating" by design, That is, most of
> the
> force that pushes the shoes against the inside of the drums is caused by
> the
> friction force of the drums on the shoes. Only a relatively small
> actuation
> force is required to start this chain reaction. That is why drum brake
> systems can easily get away without power assist.
> Think of it as being similar to a rope brake that you can make by wrapping
> a
> rope several times around a tree. You only need a small force on one end
> to
> control a very large tension force at the other end.
>
> The downside of this self-actuating system is that the final braking
> torque
> is not linear with the coefficient of friction between the shoes and drum.
> It's a much stronger function of the friction coefficient So, a small
> drop
> in friction coefficient ( due to temperature rise, for example)
> can reduce the stopping force drastically. This is what used to be called
> "brake fade".
>
> With disc brakes, the stopping torque is linearly proportional to the
> friction coefficient. A small ( or moderate) change in that coefficient
> doesn't have nearly as strong an effect on the stopping power.
>
> Phil
>
> _________________________________________________________________
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>
>
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--- End Message ---
--- Begin Message ---
On Mon, Feb 12, 2007 at 07:07:07PM -0500, Phil Marino wrote:
<..snip..>
>
> And, I would hesitate before modifying the brake system in any way ( even
> by adding a pressure sensor). If the sensor failed by blowing out or
> leaking, you would instantly have no brakes.
I'm not suggesting that a pressure transducer is the right way to go,
but isn't it true that you would only lose pressure in one of the brake
circuits?
If that is the case, then you would lose ~half of your braking ability, right?
Not great, but not as bad as losing all braking.
Thanks!
--- End Message ---
--- Begin Message ---
For those who think that white lists are a good idea, consider what would
happen if EVERYONE on the EVDL switched to using them tomorrow.
As I recall, there are approximately 1,000 users on the EVDL. So if
everyone switched tomorrow, everyone that posted a message would have to
go to 1,000 whitelists and jump through hoops so that everyone else could
get their email.
Assuming it only takes 2 minutes per whitelist, that is over 33 hours, or
almost a full work week worth of effort. For EVERYONE, including every
new user. That would be a great way to kill the list.
So for anyone who is too lazy to setup their own spam filters, well you
can sit in the dark, because I certainly don't care if you get my messages
and I expect most of the rest of the list won't do your work for you
either.
Dave has already posted one simple method of solving spam. Another is to
use one of the free email services and only accept mail from the EVDL list
server (most of them have settings for list servers).
Of course those silly people using white lists won't see this, but...oh well.
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If you send email to me, or the EVDL, that has > 4 lines of legalistic
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legalistic signature is void.
--- End Message ---
--- Begin Message ---
Phil,
Please see the graph on the page in the original link.
Output pressure is exactly 2x input pressure, so there
Is no gradual change, you may have been confused by
Their marketing term "stepped", which apparently only
Refers to the two connected pistons, the input having
Twice the diameter as the output piston, thereby
Increasing the pressure by a factor of 2.
This contradicts the text which talks about 150 to
160% but I did not make the graph and the text.
As I see it is simply two fixed connected cylinders
With two fixed connected pistons, so the output
Volume is half the input volume, which leads to a
Pressure multiplication, just as the subject says.
Regards,
Cor.
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Phil Marino
Sent: Monday, February 12, 2007 8:41 AM
To: [email protected]
Subject: RE: Brake Pressure Multiplier?
Cor-
I think you missed the main feature of this particular device.
They claim that, by using stepped cylinders, it provides a variable-leverage
system . They don't spell it out in this much detail, but my assumption is
that it behaves as a typical system for the first part of it's travel, and
then the ratio changes, so that, as you get to the "hard" part of the brake
pedal's travel, it supplies more hydraulic pressure in exchange for more
pedal motion - but just at the lower part of its travel.
If this is true, then it could do what it claims - supply substantially more
brake force at the end of pedal travel- where you need it - with only a
little more total pedal travel than a conventional system.
So, your analogy is good, in that it works similarly to a pulley system (
like any hydraulic system) .
But, in this case it works like a pulley system whose configuration ( and
mechanical advantage) changes partway through its range of motion.
Phil
>
>Paul already provided the answer and the reference to the 914 forum has
>it in even more detail:
>- if your brake cylinder diameter increased with the disk brakes,
> then you have more stopping power (at the cost of larger
> pedal travel)
>- if your disk brake cylinders are the same diameter as the drums
> then they apply the same force to the brakes. It now depends on
> the pad material if you have higher friction or not.
>- if the disk brake cylinders have smaller diameter than the drums
> then the force on the brakes is now lower, so your stopping
> power has likely deteriorated, though you should have a very
> firm feeling pedal (little travel). The BPM can help you to
> increase force on the brakes at the cost of larger pedal travel.
>
>This BPM work in the same way as a pulley system can help you to lift
>2,000 lbs of weight with only 100 lbs of force, by making the travel of
>the chain twenty times larger than the lift provided on the 2,000 lbs
>object. The power reduces, the energy stays the same (force x distance)
>just like using different gears.
>
>Hope this clarifies,
>
>Cor van de Water
> On Feb 11, 2007, at 1:22 PM, Ryan Stotts wrote:
>
> > Is this the answer to our power brakes(i.e. no vacuum booster)?
> >
> >
>http://ecihotrodbrakes.com/brake_pressure_multiplier.html<http://ecihot
>rodbr akes.com/brake_pressure_multiplier.html>
>
_________________________________________________________________
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--- Begin Message ---
I am a newbie owner of an older Voltsrabbit conversion (
http://www.austinev.org/evalbum/1020 ). I am not mechanically inclined (I'm
a EE but so far no electrical problems!) so my husband works on the car
when needed - but he's not tremendously experienced with cars either. Last
time I drove the car, the vacuum pump started running constantly. The
brakes still worked OK, but I drove straight home and haven't driven it
since. We have looked for leaks, but there is nothing that we can find so
far. I am wondering how is the best way to find a leak (assuming that's
what it is) so we can fix it up and get back on the road?
I take it that it's not safe to drive it in this condition?
This might (or might not) be coincidental: but the previous time I drove it
was to the local EAA meeting where we worked on a member's car at a local
shop. There happened to be a mechanic there who moonlights on Rabbits that
took a look at my car. After I mentioned getting pretty cold from the fresh
air vents, he said he thought he could fix it. It was a pretty simple fix -
the vent is held closed by vacuum, and there was a disconnected hose from
the vent that ran right over to the larger hose coming from the vacuum
pump. It was hanging loose, and there was a plug on a obvious connection
point for the vent vacuum hose. When we connected it up, there was a leak
in the hose to the vent. The Rabbit guy fixed that leak in the smaller vent
hose and it all seemed great - drove home with no cold air on me for 15
miles. Several days later when the vacuum pump started running constantly,
I of course replaced the hose with the plug that had been there before, but
that only fixed the vacuum pump from running for less than a mile.
I appreciate any ideas I can get!
De
--- End Message ---
--- Begin Message ---
Yes it will work. ProEV did this with their electric Subaru race car.
<http://www.proev.com/>
Sorry I can't find direct reference to it on their site. From memory
they replaced the clutch pedal with another brake pedal and master
cylinder, then used the brake light pressure transducer to control the
regen feature of their AC controller. Just as you were suggesting.
The idea was to make the regen pedal feel just like a regular brake
pedal. (They may have changed out the stock transducer with one with
an analog response instead of the stock on-off behavior.)
I don't remember clearly the reasoning behind making a separate pedal
for regen braking. One possibility: it keeps the stock braking system
free of any modifications, which is important for safety reasons.
On Feb 12, 2007, at 4:55 PM, FRED JEANETTE MERTENS wrote:
cor and phil if this is true would? will? this work then ? hook
up a variable pressure transducer that change the out put so as brake
pedal travel increases the the transducer varies the field of a
generator (or a regenerative system ) so the amount of regeneration
increases as the pedal travel increases giving more regen braking and
keeping the wear / life on the brake system to last longer ?
--
Doug Weathers
Las Cruces, NM, USA
http://www.gdunge.com/
--- End Message ---
--- Begin Message ---
Hi De,
If the brakes still work well, then there is no issue
with the pump running constantly, though it is good to
find what causes your vacuum *assist* to behave as it does.
(Even if the pump would quit entirely, you still do have
your brakes, you only need a slightly larger distance and
more pressure on the brake pedal to stop.
Tailgating with an EV is a bad idea anyway.)
It could be that the vacuum pump switch has seized in the
"on" position.
If you connect a closed hose to the pump and vacuum switch
and run it and you don't hear a leak but it still does not
shut off, chances are your vacuum switch has welded contacts.
Many Evs need a relay to reliably switch the pump, as the
vacuum switch contacts ar somewhat fragile to carry the
full current of the pump.
Careful tapping the vacuum switch (or turning it from min to
max pressure if it has a control screw) may loosen it.
If you do have a leak, then that's the cause ;-)
One way to test for vacuum is to loosen the tubes one by one
and see if plugging them makes a difference.
Also running the vacuum pump, then disconnecting it and
check for the typical hiss of a leak (which you won't hear
when the pump is running, most of the time).
If you suspect the pump itself (diaphragm) then you can
replace the pump with a bicycle or car tire pump and
see if a bit of pressure in the system leaks away.
With pressure you can also employ the water-and-soap trick
to find pinholes.
Note: most vacuum pumps can be reversed to provide pressure
and do the same check, but reverse it again before driving!
Success,
Cor.
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Deanne Mott
Sent: Monday, February 12, 2007 5:32 PM
To: [email protected]
Subject: Vacuum pump running constantly
I am a newbie owner of an older Voltsrabbit conversion (
http://www.austinev.org/evalbum/1020 ). I am not mechanically inclined (I'm
a EE but so far no electrical problems!) so my husband works on the car
when needed - but he's not tremendously experienced with cars either. Last
time I drove the car, the vacuum pump started running constantly. The
brakes still worked OK, but I drove straight home and haven't driven it
since. We have looked for leaks, but there is nothing that we can find so
far. I am wondering how is the best way to find a leak (assuming that's
what it is) so we can fix it up and get back on the road?
I take it that it's not safe to drive it in this condition?
This might (or might not) be coincidental: but the previous time I drove it
was to the local EAA meeting where we worked on a member's car at a local
shop. There happened to be a mechanic there who moonlights on Rabbits that
took a look at my car. After I mentioned getting pretty cold from the fresh
air vents, he said he thought he could fix it. It was a pretty simple fix -
the vent is held closed by vacuum, and there was a disconnected hose from
the vent that ran right over to the larger hose coming from the vacuum pump.
It was hanging loose, and there was a plug on a obvious connection point for
the vent vacuum hose. When we connected it up, there was a leak in the hose
to the vent. The Rabbit guy fixed that leak in the smaller vent hose and it
all seemed great - drove home with no cold air on me for 15 miles. Several
days later when the vacuum pump started running constantly, I of course
replaced the hose with the plug that had been there before, but that only
fixed the vacuum pump from running for less than a mile.
I appreciate any ideas I can get!
De
--- End Message ---
--- Begin Message ---
This points to one of two problems:
1) There is a vacuum leak someplace. Have you tried removing the added hose
and replacing the plug to see if that is the source of the problem?
2) the pressure switch is stuck on. this is not necessarily bad, but is
annoying. It's a simple part (pressure activated relay) available from vendors
such as evparts.com inexpensively.
David Brandt
----- Original Message ----
From: Deanne Mott <[EMAIL PROTECTED]>
To: [email protected]
Sent: Monday, February 12, 2007 8:31:43 PM
Subject: Vacuum pump running constantly
I am a newbie owner of an older Voltsrabbit conversion (
http://www.austinev.org/evalbum/1020 ). I am not mechanically inclined (I'm
a EE but so far no electrical problems!) so my husband works on the car
when needed - but he's not tremendously experienced with cars either. Last
time I drove the car, the vacuum pump started running constantly. The
brakes still worked OK, but I drove straight home and haven't driven it
since. We have looked for leaks, but there is nothing that we can find so
far. I am wondering how is the best way to find a leak (assuming that's
what it is) so we can fix it up and get back on the road?
I take it that it's not safe to drive it in this condition?
This might (or might not) be coincidental: but the previous time I drove it
was to the local EAA meeting where we worked on a member's car at a local
shop. There happened to be a mechanic there who moonlights on Rabbits that
took a look at my car. After I mentioned getting pretty cold from the fresh
air vents, he said he thought he could fix it. It was a pretty simple fix -
the vent is held closed by vacuum, and there was a disconnected hose from
the vent that ran right over to the larger hose coming from the vacuum
pump. It was hanging loose, and there was a plug on a obvious connection
point for the vent vacuum hose. When we connected it up, there was a leak
in the hose to the vent. The Rabbit guy fixed that leak in the smaller vent
hose and it all seemed great - drove home with no cold air on me for 15
miles. Several days later when the vacuum pump started running constantly,
I of course replaced the hose with the plug that had been there before, but
that only fixed the vacuum pump from running for less than a mile.
I appreciate any ideas I can get!
De
____________________________________________________________________________________
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--- End Message ---
--- Begin Message ---
To get an idea of typical chain noise, you could watch some videos on Google
of other people's electric motorcycles:
http://video.google.com/videosearch?q=electric+motorcycle&hl=en
I think most people are surprised at how noisy they are. It not as
noticeable when there is a gas engine screaming you along.
Dave O.
On 2/11/07, Jack Murray <[EMAIL PROTECTED]> wrote:
I'd really like to know how much noise the chain drive makes.
Jack
David O'Neel wrote:
> Wow, I'm having a really hard time NOT making immediate plans to put in
an
> order for one! $3-4000 is really not bad at all especially for ground-up
> design. I always liked the Gizmo as well. I could see adding a rear end
to
> it though, if for nothing else, to boost the aerodynamics a little. I
guess
> I will have to just go and have a look
>
> I wonder what the implications would be for hopping it up a bit,
although
> for most, 50mph top speed is actually plenty. Any more than that, and
you
> are competing with sparrows!
>
> Excellent..
>
> On 2/8/07, jmygann <[EMAIL PROTECTED]> wrote:
>
>>
>> http://blueskydsn.com/BugE_Concept.html
>>
>> ADvanced DC 4001 series wound motor.
>>
>> Chain drive; 6/1 ratio.
>>
>>
>>
>
>
--- End Message ---
--- Begin Message ---
This is fine in a dedicated race car, but it will
scare every other driver of your road-going EV, if it
does not make you err and crash in an emergency stop
situation in the first place....
Anyway, the usual and natural solution to the regen brake
is to use the first part of the brake pedal travel, where
the mechanical brakes do not yet engage, to drive another
potbox from zero to max. This pot controls the regen amount.
By the time the pot hits its max endstop, your mecahnical
brakes should engage and carry the increase of brake force
from there.
This works beautifully in EVs (like my US Electricar) as well
as in Hybrids such as the Toyota Prius.
If you never drove the Prius then I suggest you try it and
try to determine where the regen and where the friction
brakes provide your stopping power.
I can send you a picture of the potbox mounted next to
my brake pedal (this was a factory conversion).
Hope this helps,
Cor.
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Doug Weathers
Sent: Monday, February 12, 2007 5:43 PM
To: [email protected]
Subject: Re: Brake Pressure Multiplier?
Yes it will work. ProEV did this with their electric Subaru race car.
<http://www.proev.com/>
Sorry I can't find direct reference to it on their site. From memory they
replaced the clutch pedal with another brake pedal and master cylinder, then
used the brake light pressure transducer to control the regen feature of
their AC controller. Just as you were suggesting.
The idea was to make the regen pedal feel just like a regular brake pedal.
(They may have changed out the stock transducer with one with an analog
response instead of the stock on-off behavior.)
I don't remember clearly the reasoning behind making a separate pedal for
regen braking. One possibility: it keeps the stock braking system free of
any modifications, which is important for safety reasons.
On Feb 12, 2007, at 4:55 PM, FRED JEANETTE MERTENS wrote:
> cor and phil if this is true would? will? this work then ? hook
> up a variable pressure transducer that change the out put so as brake
> pedal travel increases the the transducer varies the field of a
> generator (or a regenerative system ) so the amount of regeneration
> increases as the pedal travel increases giving more regen braking and
> keeping the wear / life on the brake system to last longer ?
>
--
Doug Weathers
Las Cruces, NM, USA
http://www.gdunge.com/
--- End Message ---
--- Begin Message ---
Drum brakes are nonlinear -- each additional unit of pedal force produces more
braking force than before. This makes it hard to hold drum brakes right at max
braking, they'll tend to suddenly lock and skid. Disk brakes have proportional
force, pedal force in is proportional to braking force, therefore it is alot
easier to consistently brake hard without skidding with disk brakes. They also
shed water and heat better than drum brakes.
I think the only ways you can argue drum brakes are better are:
* Drum brakes take less pedal effort
* It takes less force to do a parking brake with a drum brake
----- Original Message ----
From: Peter VanDerWal <[EMAIL PROTECTED]>
To: [email protected]
Sent: Monday, February 12, 2007 6:50:43 PM
Subject: Re: Brake Pressure Multiplier?
...
Still, someone correct me if I'm wrong. but it seems to me that until you
experience brake fade, drum brakes will like provide more stopping power
per pedal effort on un-assisted brakes (due to the self-actuating
feature).
I pretty sure that sports cars went to disc brakes (even un-assisted disc
brakes) because racing involves LOTS of slowing down and speeding up.
The kind of driving that is NOT typical for most EV commuters. I'm
thinking that drum brakes might actually be better than discs in a
commuter type EV.
____________________________________________________________________________________
Never miss an email again!
Yahoo! Toolbar alerts you the instant new Mail arrives.
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--- End Message ---
--- Begin Message ---
From: Peter VanDerWal
>...it seems to me that until you experience brake fade, drum brakes will
> provide more stopping power per pedal effort on un-assisted brakes
> (due to the self-actuating feature).
>
> ...sports cars went to disc brakes (even un-assisted disc brakes) because
> racing involves LOTS of slowing down... This kind of driving is NOT typical
> for most EV commuters. I'm thinking that drum brakes might actually be
> better than discs in a commuter type EV.
I agree. Drums don't require power assist, which saves power and weight. They
are also easier to adjust so they don't drag.
If an EV has regenerative braking, the quality of the regular friction brakes
are much less important. You're more likely to use regen down a long hill.
One area where disks still excel is in wet braking. Drum brakes can fade badly
if they get wet. This can be alleviated somewhat with the proper choice of
brake linings.
--
Lee Hart
--- End Message ---
--- Begin Message ---
Even without vacuum the brakes still should work (just takes a lot more
effort).
You may or may not have a vacuum leak. It might just be that the vacuum
sensor switch is shorted/welded. Vacuum switch failure is actually fairly
common.
Check to see if your vacuum switch is internal or external to the pump.
An external switch will be wired to the pump and connected to the vacuum
lines.
The best way to see if you have a leak is to use a vacuum guages, but I'm
going to assume you don't have one.
Do you hear a hissing sound? If so that's your leak, try to find it.
If not, pull of a vacuum line while it is running and see if you hear it
at the line. If so, try plugging it with a finger and see if you feel any
suction.
If everything is good so far, disconnect the vacuum line immediately after
the switch (if the switch is inside the pump, disconnect right at the
pump. Plug the line here and see if the pump will draw enough vacuum to
activate the switch. If not and you have good vacuum from the pump, then
the problem is the switch.
If it does switch off, then keep adding back vacuum line and plugging the
far end until you find one that doesn't switch off. That line is your
problem.
If all the lines check out, hook them back up to your brake booster (big
round thing on the master cylinder). If the problem comes back when you
add the booster, then your booster has a leak. You can either rebuild it
or replace it.
> I am a newbie owner of an older Voltsrabbit conversion (
> http://www.austinev.org/evalbum/1020 ). I am not mechanically inclined
> (I'm
> a EE but so far no electrical problems!) so my husband works on the car
> when needed - but he's not tremendously experienced with cars either.
> Last
> time I drove the car, the vacuum pump started running constantly. The
> brakes still worked OK, but I drove straight home and haven't driven it
> since. We have looked for leaks, but there is nothing that we can find so
> far. I am wondering how is the best way to find a leak (assuming that's
> what it is) so we can fix it up and get back on the road?
>
> I take it that it's not safe to drive it in this condition?
>
> This might (or might not) be coincidental: but the previous time I drove
> it
> was to the local EAA meeting where we worked on a member's car at a local
> shop. There happened to be a mechanic there who moonlights on Rabbits
> that
> took a look at my car. After I mentioned getting pretty cold from the
> fresh
> air vents, he said he thought he could fix it. It was a pretty simple fix
> -
> the vent is held closed by vacuum, and there was a disconnected hose from
> the vent that ran right over to the larger hose coming from the vacuum
> pump. It was hanging loose, and there was a plug on a obvious connection
> point for the vent vacuum hose. When we connected it up, there was a leak
> in the hose to the vent. The Rabbit guy fixed that leak in the smaller
> vent
> hose and it all seemed great - drove home with no cold air on me for 15
> miles. Several days later when the vacuum pump started running
> constantly,
> I of course replaced the hose with the plug that had been there before,
> but
> that only fixed the vacuum pump from running for less than a mile.
>
> I appreciate any ideas I can get!
>
> De
>
>
--
If you send email to me, or the EVDL, that has > 4 lines of legalistic
junk at the end; then you are specifically authorizing me to do whatever I
wish with the message. By posting the message you agree that your long
legalistic signature is void.
--- End Message ---
--- Begin Message ---
Cool - lots of things for us to try. Folks on this list are the greatest!
Glad to know I can drive it, but on my nutso interstate commute I'll be
hanging way back.
To clear up a few points asked:
Yes, I did remove the vent hose and put the plug back in. That worked for
about 1 minute.
Also, I think I can eliminate the switch because we put some hose clamps in
a couple of places to try to find the leak. That worked for about 2 seconds
- then the pump "burped" on a few times, then was on solid again. BTW, it
has been "burping" (is there a technical term for that?) every 10 seconds or
so since I got it. Figured I had a slow leak, but was not motivated to look
for it until now.
On 2/12/07, Peter VanDerWal <[EMAIL PROTECTED]> wrote:
Even without vacuum the brakes still should work (just takes a lot more
effort).
You may or may not have a vacuum leak. It might just be that the vacuum
sensor switch is shorted/welded. Vacuum switch failure is actually fairly
common.
Check to see if your vacuum switch is internal or external to the pump.
An external switch will be wired to the pump and connected to the vacuum
lines.
The best way to see if you have a leak is to use a vacuum guages, but I'm
going to assume you don't have one.
Do you hear a hissing sound? If so that's your leak, try to find it.
If not, pull of a vacuum line while it is running and see if you hear it
at the line. If so, try plugging it with a finger and see if you feel any
suction.
If everything is good so far, disconnect the vacuum line immediately after
the switch (if the switch is inside the pump, disconnect right at the
pump. Plug the line here and see if the pump will draw enough vacuum to
activate the switch. If not and you have good vacuum from the pump, then
the problem is the switch.
If it does switch off, then keep adding back vacuum line and plugging the
far end until you find one that doesn't switch off. That line is your
problem.
If all the lines check out, hook them back up to your brake booster (big
round thing on the master cylinder). If the problem comes back when you
add the booster, then your booster has a leak. You can either rebuild it
or replace it.
> I am a newbie owner of an older Voltsrabbit conversion (
> http://www.austinev.org/evalbum/1020 ). I am not mechanically inclined
> (I'm
> a EE but so far no electrical problems!) so my husband works on the car
> when needed - but he's not tremendously experienced with cars either.
> Last
> time I drove the car, the vacuum pump started running constantly. The
> brakes still worked OK, but I drove straight home and haven't driven it
> since. We have looked for leaks, but there is nothing that we can find
so
> far. I am wondering how is the best way to find a leak (assuming that's
> what it is) so we can fix it up and get back on the road?
>
> I take it that it's not safe to drive it in this condition?
>
> This might (or might not) be coincidental: but the previous time I drove
> it
> was to the local EAA meeting where we worked on a member's car at a
local
> shop. There happened to be a mechanic there who moonlights on Rabbits
> that
> took a look at my car. After I mentioned getting pretty cold from the
> fresh
> air vents, he said he thought he could fix it. It was a pretty simple
fix
> -
> the vent is held closed by vacuum, and there was a disconnected hose
from
> the vent that ran right over to the larger hose coming from the vacuum
> pump. It was hanging loose, and there was a plug on a obvious
connection
> point for the vent vacuum hose. When we connected it up, there was a
leak
> in the hose to the vent. The Rabbit guy fixed that leak in the smaller
> vent
> hose and it all seemed great - drove home with no cold air on me for 15
> miles. Several days later when the vacuum pump started running
> constantly,
> I of course replaced the hose with the plug that had been there before,
> but
> that only fixed the vacuum pump from running for less than a mile.
>
> I appreciate any ideas I can get!
>
> De
>
>
--
If you send email to me, or the EVDL, that has > 4 lines of legalistic
junk at the end; then you are specifically authorizing me to do whatever I
wish with the message. By posting the message you agree that your long
legalistic signature is void.
--- End Message ---
--- Begin Message ---
Hi De,
This either indicates you always had a leak, or
(like my pump switch) the hysteresis between the
low setpoint ( enabling the pump) and high setpoint
(disabling it) is too small, so the pump will bounce
the pressure up and down between these limits.
I know what you mean, when the pump comes on I hear
a Burrr---burrrr---burrr, running it every 10 secs or so.
In this case, a different switch with a larger hysteresis
can help if you can't find a leak....
If the pump comes on / switches off several times and
then it starts running continuously, that indicates a
faulty switch.
You can test pump + switch + plugged hose to see if it
switches off at all after the initial few runs, then
see if it has vacuum - then you know it's the switch.
Cor.
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Deanne Mott
Sent: Monday, February 12, 2007 6:27 PM
To: [email protected]
Subject: Re: Vacuum pump running constantly
Cool - lots of things for us to try. Folks on this list are the greatest!
Glad to know I can drive it, but on my nutso interstate commute I'll be
hanging way back.
To clear up a few points asked:
Yes, I did remove the vent hose and put the plug back in. That worked for
about 1 minute.
Also, I think I can eliminate the switch because we put some hose clamps in
a couple of places to try to find the leak. That worked for about 2 seconds
- then the pump "burped" on a few times, then was on solid again. BTW, it
has been "burping" (is there a technical term for that?) every 10 seconds or
so since I got it. Figured I had a slow leak, but was not motivated to look
for it until now.
On 2/12/07, Peter VanDerWal <[EMAIL PROTECTED]> wrote:
>
> Even without vacuum the brakes still should work (just takes a lot
> more effort).
>
> You may or may not have a vacuum leak. It might just be that the
> vacuum sensor switch is shorted/welded. Vacuum switch failure is
> actually fairly common.
> Check to see if your vacuum switch is internal or external to the pump.
> An external switch will be wired to the pump and connected to the
> vacuum lines.
>
> The best way to see if you have a leak is to use a vacuum guages, but
> I'm going to assume you don't have one.
>
> Do you hear a hissing sound? If so that's your leak, try to find it.
> If not, pull of a vacuum line while it is running and see if you hear
> it at the line. If so, try plugging it with a finger and see if you
> feel any suction.
>
> If everything is good so far, disconnect the vacuum line immediately
> after the switch (if the switch is inside the pump, disconnect right
> at the pump. Plug the line here and see if the pump will draw enough
> vacuum to activate the switch. If not and you have good vacuum from
> the pump, then the problem is the switch.
> If it does switch off, then keep adding back vacuum line and plugging
> the far end until you find one that doesn't switch off. That line is
> your problem.
> If all the lines check out, hook them back up to your brake booster
> (big round thing on the master cylinder). If the problem comes back
> when you add the booster, then your booster has a leak. You can
> either rebuild it or replace it.
>
> > I am a newbie owner of an older Voltsrabbit conversion (
> > http://www.austinev.org/evalbum/1020 ). I am not mechanically
> > inclined (I'm a EE but so far no electrical problems!) so my
> > husband works on the car when needed - but he's not tremendously
> > experienced with cars either.
> > Last
> > time I drove the car, the vacuum pump started running constantly.
> > The brakes still worked OK, but I drove straight home and haven't
> > driven it since. We have looked for leaks, but there is nothing
> > that we can find
> so
> > far. I am wondering how is the best way to find a leak (assuming
> > that's what it is) so we can fix it up and get back on the road?
> >
> > I take it that it's not safe to drive it in this condition?
> >
> > This might (or might not) be coincidental: but the previous time I
> > drove it was to the local EAA meeting where we worked on a member's
> > car at a
> local
> > shop. There happened to be a mechanic there who moonlights on
> > Rabbits that took a look at my car. After I mentioned getting
> > pretty cold from the fresh air vents, he said he thought he could
> > fix it. It was a pretty simple
> fix
> > -
> > the vent is held closed by vacuum, and there was a disconnected hose
> from
> > the vent that ran right over to the larger hose coming from the
> > vacuum pump. It was hanging loose, and there was a plug on a
> > obvious
> connection
> > point for the vent vacuum hose. When we connected it up, there was
> > a
> leak
> > in the hose to the vent. The Rabbit guy fixed that leak in the
> > smaller vent hose and it all seemed great - drove home with no cold
> > air on me for 15 miles. Several days later when the vacuum pump
> > started running constantly, I of course replaced the hose with the
> > plug that had been there before, but that only fixed the vacuum pump
> > from running for less than a mile.
> >
> > I appreciate any ideas I can get!
> >
> > De
> >
> >
>
>
> --
> If you send email to me, or the EVDL, that has > 4 lines of legalistic
> junk at the end; then you are specifically authorizing me to do
> whatever I wish with the message. By posting the message you agree
> that your long legalistic signature is void.
>
>
--- End Message ---
