OT: Nitrogen filled tires

[Don Lancaster]

No you would not. An IR sensor pointed at the inside wall of the
OUTSIDE of the tire would work just fine, and the settle time difference
would be negligible for these purposes. Also, a simple inner rim
measurement would be even more accurate as metal conducts very well, and
would translate nearly the same temp as the air in the tire.

That still does not discount the FACT that a pump ON the wheel is a
bad idea.

Existing tire pressure warning devices either already measure
temperature or could be modified to do so.

The pump part, of course, is ludicrous.

--
Many thanks,

Don Lancaster voice phone: (928)428-4073
Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
rss: http://www.tinaja.com/whtnu.xml email: [email protected]

Please visit my GURU's LAIR web site at http://www.tinaja.com

 

[John Larkin]

Oh, dear, I see a snag. To temperature-compensate the regulator, you'd
have to measure the temperature _inside_ the tire.

Thanks,
Rich

Why temperature compensate the regulator? Just keep the tires at
constant pressure; pump or bleed as appropriate.

John

 

[John Larkin]

Existing tire pressure warning devices either already measure
temperature or could be modified to do so.

The pump part, of course, is ludicrous.

Might you, Oh Great One, please explain why? And why a mems pressure
sensor and RF transmitter per wheel, battery powered, with all the
receiver and display stuff, is a better idea?

It's sort of ironic that people are trying to use the motion of the
wheel to generate enough power to run the electronics, to get rid of
the battery.

John

 

[John Larkin]

John Larkin wrote:
On Mon, 15 Oct 2007 16:48:33 -0700, Jim Thompson


On Mon, 15 Oct 2007 16:37:01 -0700, John Larkin


On Mon, 15 Oct 2007 16:32:10 -0700, Jim Thompson


On Mon, 15 Oct 2007 16:23:39 -0700, John Larkin






[snip]

No,he's right;those wheel spinners use low friction bearings,and any
crud will stop them.

So, you won't do the math either.

John





Math without practical experience is useless.

Practical experience without math is amateur guesswork.

John

John, I think you've got yourself out on a limb, on the wrong side of
the saw ;-)

I think it's you who has to put some numbers to it.

...Jim Thompson

I already did. And Guy confirmed it.

John

Macon?? That's almost as good as having "...bored..." do it ;-)


No, MissingProng can't do math at all. He's entirely number-phobic.


I think you need a pendulum of _substantial weight_ so that it
_doesn't rotate, but acts as a "pinning" point for the piston(s).


That could work, too. But we'd need a small amount of energy per day.
I'm guessing 1 kilojoule would be plenty - and easy to get - based on
the performance of a little cigaret-lighter-plugin compressor I have.
The bling-spinner idea was cute, and would be a nice sales gimmick.



What
weight does it take for a 1/2" piston working against 30PSI, and what
are the respective arm lengths?


Why 1/2"? The amount of air we'd need is tiny.

I'm not going to design it, much less build one to prove something to
rude strangers, but the numbers seem well in the ballpark of
feasibility. That's the first step in engineering, a quick numerical
estimate to see if an idea has a chance of working. This one does.

John



Low tire pressure alarms will become standard and manditory in a year or
two.
They already are stock on high end vehicles.


They are ridiculously more cost effective than zillions of pumps that
does nothing for virtually all of their lifetimes.

But pumps fill tires, and alarms don't.

And a small pump would work pretty much continuously.

I say again. It is a fucking RETARDED IDEA!


Put a pump in a shock tower, fill a surge tank once every few days, and
have air on demand whenever needed.

We don' need no stinking miniature dysfunctional pumps.

Just so you know, a surge tank IS required for any of your hair brained
ideas to work, as well as my 100% viable idea.

Why does a small regulated pump, topping off a tire, need a "surge
tank"?

John

 

[Guy Macon]

Then there's the problem of getting/keeping the correct tire pressure under
varying tire temperatures.If your auto-pump continuously pumps,you could
over-pressure your tires(when they heat up) and they would wear too
fast,particularly in the center of the tread.

Pressure regulators with a wide variety of temperature curves
are a mature technology. When I worked as a design engineer
for SMC Pneumatics, regulating pressure so that it stays constant
as temperature varies was one of the most common configurations.

 

[Guy Macon]

One that accounts for tire temperature?

Not needed. Constant pressure at the regulator would work
fine. Keeping the pressure in the tire constant as it heats
up is not a requirement, and is not something that the existing
system (check pressure every so often, add air as needed) has.

more complexity, more chance for failure. More cost,too.

Add too much stuff to it,and it sooner becomes impractical.

The claim that is being disputed is "it won't work." Whether
it would cost too much, be reliable enough, etc., are matters
best discussed after those who claim that it wont work either
admit their error or do some math that supports their assertion.

 

[Jim Yanik]

It's sort of ironic that people are trying to use the motion of the
wheel to generate enough power to run the electronics, to get rid of
the battery.

John

Why? modern electronics uses so little power.
electromagnetic induction easily generates sufficient power for that
purpose. look at RFID chips.

and batteries fail,leak,eventually lose recharge capability.
They ARE the weakest link. ;-)


BTW,to control a mechanical pressure regulator,it will take more power than
a simple pressure monitor uses.

 

[Jim Yanik]

Why temperature compensate the regulator? Just keep the tires at
constant pressure; pump or bleed as appropriate.

John

You can bleed off pressure a lot easier (and quicker)than raise
it,especially with your proposed system.(your device would bleed a hot
tire,and then when the vehicle gets parked for a half hour,the pressure is
too low,and your device does not pump when the vehicle is at rest.it also
will take a long time to raise pressure.)

one more thing to fail and possibly cause a tire to fail when you least
need it to fail.
suppose your regulator fails and rapidly bleeds all(or just too much)of the
air out of a tire(at 70MPH)? some vehicles have catastrophic tire failure
when that happens,some have rollover crashes.
Some just lose control.

 

[Don Lancaster]

Why? modern electronics uses so little power.
electromagnetic induction easily generates sufficient power for that
purpose. look at RFID chips.

and batteries fail,leak,eventually lose recharge capability.
They ARE the weakest link. ;-)


BTW,to control a mechanical pressure regulator,it will take more power than
a simple pressure monitor uses.

The batteries in the current units are rated for three times the
expected life of the car.

The current state of the art of warning units is quite simple and cheap;
they undoubetedly will get a lot cheaper and simpler.

The concept of a pump is clearly ludicrous.

--
Many thanks,

Don Lancaster voice phone: (928)428-4073
Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
rss: http://www.tinaja.com/whtnu.xml email: [email protected]

Please visit my GURU's LAIR web site at http://www.tinaja.com

 

[Don Lancaster]

The batteries in the current units are rated for three times the
expected life of the car.

The current state of the art of warning units is quite simple and cheap;
they undoubetedly will get a lot cheaper and simpler.

The concept of a pump is clearly ludicrous.

The next generation tire pressure monitors should be the size and shape
of a valve cap and will likely cost under a dollar.

Their per unit savings in fuel economy, accident reduction, etc...
should provide a cost benefit ratio of many hundreds to one.

Replacing one of these with ANYTHING that is in ANY way mechanical makes
no sense whatsoever.

==========================

Also, many 4WD drivers I know will dramatically change their tire
pressures a dozen times on a single trip.

--
Many thanks,

Don Lancaster voice phone: (928)428-4073
Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
rss: http://www.tinaja.com/whtnu.xml email: [email protected]

Please visit my GURU's LAIR web site at http://www.tinaja.com

 

[Guy Macon]

The batteries in the current units are rated for three times the
expected life of the car.

I was under the impression that no primary batteries are rated
for more than ten years. An I behind the times on battery
technology, or are they assuming a 3-year life for the car?

 

[Don Lancaster]

Don Lancaster wrote:




I was under the impression that no primary batteries are rated
for more than ten years. An I behind the times on battery
technology, or are they assuming a 3-year life for the car?

A major story on this in either EE Times or ED a month or so back, with
full details. I was surprised that battery replacement was simply not a
factor.


--
Many thanks,

Don Lancaster voice phone: (928)428-4073
Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
rss: http://www.tinaja.com/whtnu.xml email: [email protected]

Please visit my GURU's LAIR web site at http://www.tinaja.com

 

[Guy Macon]

Replacing one of these with ANYTHING that is in ANY way
mechanical makes no sense whatsoever.

Wow. Words written in all caps. I was had my doubts about whether
you were right, but as soon as I saw those words in all caps, I
Knew that you must be right.

Unless someone comes along and uses all caps and multiple exclamation
points, of course. That's even more convincing.

 

[Jim Yanik]

Jim Yanik wrote:

The batteries in the current units are rated for three times the
expected life of the car.

What type of battery? Lithium?
(and what is the "expected life" of a new auto?)

 

[John Larkin]

The next generation tire pressure monitors should be the size and shape
of a valve cap and will likely cost under a dollar.

Their per unit savings in fuel economy, accident reduction, etc...
should provide a cost benefit ratio of many hundreds to one.

A pressure monitor does none of those things. Adding air does.

John

 

[Rich Grise]

What type of battery? Lithium?
(and what is the "expected life" of a new auto?)

The lifetime of the owner, if driven carelessly enough. ;-)

Cheers!
Rich

 

[krw]

Oregon.

New Jersey.

 

[krw]

Ah,the standard liberal comeback;"civilized".How elitist.
(so much for their vaunted "diversity";if you're not like us,you're
"uncivilized".)

LOL! Are you calling me a "liberal"? The only one who can get away
that is my wife (she's the only one on the planet to the right of
me. You gotta admit, the Orlando area is Mickey-Mouse.

Did you hear about the Democrats calling for(and getting) immunizations
before attending a NASCAR race? I guess that sort is too icky for the
Democrats to be near without having their shots.

Sure. Now *that* is classical "neo-lib".

No,inexpensive,but not "cheap".
It has a powerful motor,not some slot-car salvage,metal gears,all-metal
housing,and is quiet compared to those "cheapo" auto compressors.
$21 was the SALE price,including a rebate.It's similar to what AAA
responders have in their service vehicles.(but not chrome plated like
theirs)

Of course,you didn't bother to check it out before tagging it as "cheapo".

Of course not. I have no need for one. My tires stay inflated.

Which doesn't do you any good away from home...

Don't need one away from home either. A can of fix-a-flat works
well.

(and I can't run a compressor in my apartment,it disturbs the neighbors)

If they're living in an apartment, tell them to get used to it. The
clods jumping on my ceiling don't much care about noise, either.
Besides, those little compressors are pretty damned loud!

 

[ChairmanOfTheBored]

Might you, Oh Great One, please explain why? And why a mems pressure
sensor and RF transmitter per wheel, battery powered, with all the
receiver and display stuff, is a better idea?

It's sort of ironic that people are trying to use the motion of the
wheel to generate enough power to run the electronics, to get rid of
the battery.

The MEMS device could easily be powered by a nearby, OFF TIRE inductive
or RF feed.

The MEMES device REPORTS to the driver, the condition of each wheel,
and the DRIVER then decides if there is an issue. FAR cheaper than
little complex, and stupid "compressors" that would present a far bigger
load than you think to whatever mechanism you come up with to drive it,
and both it and the mechanism add significantly to the unsprung weight of
the wheel.

Even a spinner/hose assembly for filling it from a surge tank/regulator
assembly mounted on the chassis adds to the unsprung weight. Still, not
nearly as much as your spinner CRAP does or would.

Just 'cause drivers out there are using them doesn't make spinners
escape the stupid awards it garners from the automotive engineering
realm.

 

[ChairmanOfTheBored]

John Larkin wrote:
On Mon, 15 Oct 2007 16:48:33 -0700, Jim Thompson


On Mon, 15 Oct 2007 16:37:01 -0700, John Larkin


On Mon, 15 Oct 2007 16:32:10 -0700, Jim Thompson


On Mon, 15 Oct 2007 16:23:39 -0700, John Larkin






[snip]

No,he's right;those wheel spinners use low friction bearings,and any
crud will stop them.

So, you won't do the math either.

John





Math without practical experience is useless.

Practical experience without math is amateur guesswork.

John

John, I think you've got yourself out on a limb, on the wrong side of
the saw ;-)

I think it's you who has to put some numbers to it.

...Jim Thompson

I already did. And Guy confirmed it.

John

Macon?? That's almost as good as having "...bored..." do it ;-)


No, MissingProng can't do math at all. He's entirely number-phobic.


I think you need a pendulum of _substantial weight_ so that it
_doesn't rotate, but acts as a "pinning" point for the piston(s).


That could work, too. But we'd need a small amount of energy per day.
I'm guessing 1 kilojoule would be plenty - and easy to get - based on
the performance of a little cigaret-lighter-plugin compressor I have.
The bling-spinner idea was cute, and would be a nice sales gimmick.



What
weight does it take for a 1/2" piston working against 30PSI, and what
are the respective arm lengths?


Why 1/2"? The amount of air we'd need is tiny.

I'm not going to design it, much less build one to prove something to
rude strangers, but the numbers seem well in the ballpark of
feasibility. That's the first step in engineering, a quick numerical
estimate to see if an idea has a chance of working. This one does.

John



Low tire pressure alarms will become standard and manditory in a year or
two.
They already are stock on high end vehicles.


They are ridiculously more cost effective than zillions of pumps that
does nothing for virtually all of their lifetimes.

But pumps fill tires, and alarms don't.

And a small pump would work pretty much continuously.

I say again. It is a fucking RETARDED IDEA!


Put a pump in a shock tower, fill a surge tank once every few days, and
have air on demand whenever needed.

We don' need no stinking miniature dysfunctional pumps.

Just so you know, a surge tank IS required for any of your hair brained
ideas to work, as well as my 100% viable idea.

Why does a small regulated pump, topping off a tire, need a "surge
tank"?

John

Maybe because your little pencil lead sized piston would take a week to
add a single pound of pressure to a tire. Whereas if you had a full
surge tank on the chassis, the wheel could be filled in real time, on
demand.

That need alone (real time response)is a deal breaker for your "design
idea".