[Diy_efi] Re: Diy_efi digest, Vol 1 #343 - 8 msgs

[Bill Washington]

Gents,
	The hot wire is used as part of a resistor bridge network.
I would be more concerned about aging of the other resistors in the bridge because they will affect the static balance current, therefore the temperature of the hot wire, therefore the degree of cooling any given airflow causes, and therefore the current change to balance it out and the current change is what is used to determine the airflow!

	Likewise the MAP (pressure) sensors are electro/mechanical devices again operating on the bridge principle - same aging issues for the other resistors apply! but also with the airflow, turbulance, Bernoulli and pulsations placement and interpretation of the measured value is also critical!

	Any comments?
Bill

Message: 6
Date: Sun, 3 Nov 2002 21:05:37 -0800 (PST)
From: Adam Wade <espresso_doppio at yahoo.com>
Subject: Re: [Diy_efi] Newbie with a simplified Motronic project
To: diy_efi at diy-efi.org
Reply-To: diy_efi at diy-efi.org

--- Bevan Weiss <kaizen__ at hotmail.com> wrote:


>> I'm not sure of where you can obtain a stable metal.
>  
>

I am under the impression that some alloys of titanuim
are extremely stable of a great range of temperatures
and time.

If I am not mistaken, the hot wire used in a number of
MAF sensors is a titanium alloy element.

Looks like a lot of them use a zirconia element, which
I think is even more stable.  I'm not even sure what
it really is, structurally; I've seen references to
ceramic, but that's not very descriptive.  Still, it
would seem that MAF sensors are incredibly stable over
time and age, and a wide heat range.

I'd be far more worried about the air intake temp
sensor, or a dirty TPS, myself.

=====
| Adam Wade                       1990 Kwak Zephyr 550 (Daphne) |
|   http://y42.photos.yahoo.com/bc/espresso_doppio/lst?.dir=/   |
| "It was like an emergency ward after a great catastrophe; it  |
|   didn't matter what race or class the victims belonged to.   |
|  They were all given the same miracle drug, which was coffee. |
|   The catastrophe in this case, of course, was that the sun   |
|     had come up again."                    -Kurt Vonnegut     |

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