electronic throttle

not true. electronics are much more reliable. and they /do/ offer
significant improvement in mileage and pollution control. they offer
significantly better control for things like cruise control and
automatic transmissions too.

 

Rodan wrote:

....(adding a gas pedal position sensor) has nothing to do with saving
money. It costs more, it's more complex, it adds more electromechanical
hardware and increases electrical, mechanical, and computer interfaces.
It introduces multiple new failure modes, while yielding no significant
improvement in gas mileage or pollution control. It is a money pit,
a maintenance nightmare and a death trap waiting for a victim.
________________________________________________________________________

:

not true. electronics are much more reliable. and they /do/ offer
significant improvement in mileage and pollution control. they
offer significantly better control for things like cruise control and
automatic transmissions too.
__________________________________________________________________________

I may not be seeing the tradeoff benefits you refer to.
How does adding a gas pedal position sensor provide:

"significant improvement in mileage and pollution
control and significantly better control for things
like cruise control and automatic transmissions too" ?

Rodan.

 

because it provides you the means to have a proper control system
between the pedal and the engine. diesels have /always/ had a control
system between the driver than the engine since day one. modern "fly by
wire" is simply the next step - as stated before, it best for things
like ability to have better cruise, de-throttling during shifts, and to
better match throttle position with load.

 

These linear Hall effect sensors do indeed exist - and being non contact are
arguably highly reliable
http://www.potentiometers.com/select_hall.cfm

Dave

 

interesting. but at >10x the price of a simple potentiometer solution,
which is afterall, also known to be highly reliable, would an auto
manufacturer really use one?

 

You should both appear on the UK TV programme Grumpy Old Men (I kid you not)
as Grand Seniors...

DAS

To reply directly replace 'nospam' with 'schmetterling'
--

 

Well Jim B. says that they cost 10 times what a pot. would cost, so *no*
manufacturer would *ever* use them - so your statement just *can't* be
true. [rolls eyes] I guess that Toyota didn't check the price on the
parts before they designed them in - yeah - that must be what happened.
LOL!

 

Sure. That's why all those cables in past cars went haywire and opened
up throttles. Preaching to the choir, you are.
You recall all the incidents of million-car recalls because of that,
right?

Sure. Thousands of time, probably. Millions of cars were recalled for
that, weren't they? Throttles going wide open all over the place.
Those were terrible times.

Right. That's why multiple transitors, resistors, lines of code, servo
motors, and yards and yards of wiring are so much more dependable than a
cable and a return spring attached to the driver's foot via a pedal.
Just makes sense.

 

You are wrong. Hall effect sensors are used instead of potentiometers
in all kinds of "variable output" controls including the throttles on
virtually all the electric scooters and e-bikes you see out there.

They are called "Ratiometric Linear Hall Effect Sensors.

Patent 6091238

The present invention incorporates a system for varying the output
signal and regulating the power consumed by an electrical device. It
achieves its purpose by moving a magnet relative to a Hall effect
sensor which is responsive to an intersecting magnetic field. The Hall
effect sensor creates an electrical output signal which determines the
input signal of an output element of the device. The electrical Hall
effect sensor signal thereby controls the output signal emitted by the
electrical output element. The magnet is moved using a movable
element. Since the location and movement of the magnet regulates the
Hall effect sensor output signal, the output signal of the electrical
device as well as its rate of change are regulated using the movable
element. In order to conserve power the Hall effect sensor element is
usually not energized when the device is in the "off" mode. However a
switching means correlated with the position of the movable element
energizes the Hall effect sensor when the magnet has created a
magnetic field of acceptable density and direction.


Also:
http://www.alliedelec.com/Images/Products/Datasheets/BM/HONEYWELL_ELECTROCORP/642-2257.PDF

SS495A
SS490 Series Standard Miniature Ratiometric Linear Hall-Effect Sensor;
radial lead IC package
Actual product appearance may vary.
Features
l Small size
l Low power consumption
l Single current sinking or current
sourcing linear output
l Built-in thin-film resistors - laser trimmed for precise sensitivity
and temperature compensation
l Rail-to-rail operation provides more useable signal for higher
accuracy
l Responds to either positive or negative gauss
l Quad Hall sensing element for stable output)
Potential Applications
l Current sensing
l Motor control
l Position sensing
l Magnetic code reading
l Rotary encoder
l Ferrous metal detector
l Vibration sensing
l Liquid level sensing
l Weight sensing
Description
SS490 Series MRL (Miniature Ratiometric Linear) sensors have a
ratiometric output voltage, set by the supply voltage. It varies in
proportion to the strength of the magnetic field.
A new Hall effect integrated circuit chip provides increased
temperature stability and sensitivity. Laser trimmed thin film
resistors on the chip provide high accuracy and temperature
compensation to reduce null and gain shift over temperature.
The quad Hall sensing element minimizes the effects of mechanical or
thermal stress on the output. The positive temperature coefficient of
the sensitivity helps compensate for the negative temperature
coefficients of low cost magnets,
providing a robust design over a wide temperature range.
NOTE: Products ordered in bulk packaging (plastic bags) may not have
perfectly straight leads as a result of normal handling and shipping
operations. Please order tape packaging option for applications with
critical lead straightness requirements.

Also see: http://www.allegromicro.com/en/Products/Part_Numbers/1321/
A1321, A1322, and A1323
Ratiometric Linear Hall Effect Sensor ICs for High-Temperature
Operation
Output voltage proportional to magnetic flux density
Ratiometric rail-to-rail output
The A132X family of linear Hall-effect sensor ICs are optimized,
sensitive, and temperature-stable. These ratiometric Hall-effect
sensor ICs provide a voltage output that is proportional to the
applied magnetic field. The A132X family has a quiescent output
voltage that is 50% of the supply voltage and output sensitivity
options of 2.5 mV/G, 3.125 mV/G, and 5 mV/G. The features of this
family of devices are ideal for use in the harsh environments found in
automotive and industrial linear and rotary position sensing systems.

Each device has a BiCMOS monolithic circuit which integrates a Hall
element, improved temperature-compensating circuitry to reduce the
intrinsic sensitivity drift of the Hall element, a small-signal
high-gain amplifier, and a rail-to-rail low-impedance output sta

Nope. You are WAY out of date. Hall effect sensors measure magnetic
flux.

 

You need to understand emission controls and engine control - which
you obviously don't, in order to understand HOW ECT makes it better.

 

They use them all the time. They are not subject to wear, electrical
degradation, resistance change due to contamination, etc - etc. - etc.

Absolutely no reason NOT to use them as they are SIGNIFICANTLY more
reliable in the long term.

 

You can believe what you like. Properly designed and implemented
electronic controls are more reliable than properly designed and built
mechanical systems. Ther is NO WEAR, and NO MOVING PARTS. Moving parts
either wear or seize or break in time.
If electronic devices are operated within their design voltage and
temperature parameters they can last virtually forever. 10s of
thousands of operating hours at the minimum.

 

The entire rationale for electronics over mechanical is emissions and
performance mapping.

 

I've replaced more TAC throttle bodies in the last year than throttle
cables in my lifetime.

 

You forget one thing: Modern (automotive) electronics are made using
surface mount components, and surface mount solder bonds (as currently
done in the modern automotive world) are particularly bad at
withstanding years of thermal cycling and other environmental exposure.
All these electronic module failures (hard and intermittent) are
probably 90+% due to the failure of surface mount component-to-board
bonds. A chain is only as strong as its weakest link - and that is it.

You might argue "Well, then they aren't properly designed and
implemented, are they?". That may be true, but it is a fact that you
can't get away from in the present state of automotive electronic
manufacturing.

I claim that the admission has to be one of two things:
(1) Surface mount electronics as currently utilized in the present
automotive industry do not fit into the category of "proper design and
implementation", or
(2) Even properly designed and implemented electronics (by modern
standards of the automotive industry) are prone to failure.

Perhaps you would choose (1)? Or do you not accept that electronic
modules in our automobiles have real failure rates over the life of the
vehicle?

You might have one valid counter to this if you were to say that a
proper design would be fail safe (for the uninitiated, that means that
things may fail, but when they do, they do so in a safe manner). But
then, can we anticipate all failure modes and analyze their results? (I
have served on FMEA teams for major manufacturers, so I know what I'm
talking about in this area.) It probably is a circular argument,
because you could always claim that "...then it is not properly designed
and implemented, is it?", and I couldn't disagree with you.

Perhaps this relates back to some of the Toyota problems, perhaps not.
But electronics do fail - you have to decide if that is due to (1) or
(2) above.

 

Rodan wrote:

(adding an accelerator pedal position sensor) costs more, it's more
complex, it adds more electromechanical hardware and increases
electrical, mechanical, and computer interfaces. It introduces
multiple new failure modes, while yielding no significant improvement
in gas mileage or pollution control. It is a money pit, a maintenance
nightmare and a death trap waiting for a victim.
____________________________________________________________________

wrote:

You need to understand emission controls and engine control
which you obviously don't, in order to understand HOW ECT
makes it better.
___________________________________________________________________

I thought that might be the answer. In the absence of any
numbers to show that the gadget-laden accelerator sensor
nightmare adds any gas mileage whatsoever or reduces any
pollution whatsoever, the response is essentially, "You're too
dumb to understand."

You've got me there. Henceforth, I'll treat it as a religious
question for which the answer is too complex for a mere
mortal, to be entrusted only to qualified gurus.

Best regards to all RAGers.

Rodan.

 

'ere ya go. (But as I just posted, the claim could be "Well, then the
design was not properly designed and implemented, was it?", and
eventually it becomes a semantical argument that would continue in
circles ad infinitum - not that that would ever happen on a newsgroup.
LOL!)

 

More research brings MORE interesting information.
A "hall effect switch" is an adaptation of the basic "hall effect
sensor", where a schmitt trigger and a comparator use the hall voltage
to produce a "digital" signal.

The basis of a hall effect sensor (the hall effect) is when current
flows through a conductor in the presence of a magnetic field a
voltage is produced at right angles to the current flow, and it varies
with magnetic flux in both level and polarity.

 

All of which can also cause a cable or mechanical lncage to stick- - -
- - - -