REFLECTOR:FADEC info

[Dennis Martin]

My Electromotive FADEC (for Chevy V-6 odd fire engine) has EGT failure 
mode backup - engine automatically goes into limp home mode if any one 
of the sensors goes south.  I also have two magnetic hall sensors, one 
for each bank of cylinders.  If one goes out, I'll run a bit rough, but 
can still limp home with half of the pistons still firing.  Same for 
six-pack set of coils.  If one goes out (or a bank of three goes out), 
I still have a back-up set of coils.  Nothing's fail-safe, but this is 
how they designed the computer.  I'm installing two computers, just in 
case.

Dennis Martin

On Saturday, December 20, 2003, at 04:31 PM, Jim Sower wrote:

> <... safe to say that (probably) all of the gotcha scenarios have been 
> addressed ...>
> That's comforting.  I had hoped that my questions were specific enough 
> to warrant
> specific answers.  I think it would be interesting to know, if EGTs 
> were driving fuel
> delivery, how they address failure modes such as gradual deterioration 
> (inaccurate
> output) of the probes and how one might go about distinguishing 
> between a
> deteriorating EGT probe and a deteriorating something else (like 
> cylinder) that has a
> similar effect on EGT.
>
> But then again, my questions were somewhat rhetorical.  I am much more 
> interested in
> auto conversions for a variety of reasons not least of which is that I 
> am not in a
> position to spend what FADEC costs.  Seems to me that spending all 
> those thousands of
> $ to put a "modern" face on an anachronistic Lyc is an exercise in 
> trying to make a
> silk purse out of a sow's ear.
>
> Will it be as reliable and accurate as late model automotive fuel 
> controls? ... Jim S.
>
> Wayne Lanza wrote:
>
>> Hi Jim,
>>   If you haven't been made aware of the Aerosance web site - here ya
>> go...
>> I worked closely for a week with the designers of the system while
>> installing
>> the Continental FADEC system in Velocity's XL Dash 5 demonstrator
>> aircraft.
>> They have designed many failure mode operations into the system, safe 
>> to
>> say that (probably) all of the gotcha scenarios have been addressed.
>>
>> Have a Great Holiday,
>> Wayne Lanza
>> Composite Design
>>
>> goto the Aerosance web page at - http://www.FADEC.com
>> ________________________________________________________________
>>
>> On Thursday, December 18, 2003, at 11:16 PM, Jim Sower wrote:
>>
>>> I need some help with some specifics on how FADEC works.
>>> <... FADEC system meters the fuel-air mixture to ... power ... 100
>>> degrees Rich of
>>> peak ... cruise ... 100 degrees Lean of peak ...>
>>>
>>> Is it safe to assume that this FADEC feature is driven by EGT 
>>> sensors?
>>>
>>> Is it further safe to assume that FADEC varies fuel delivery from one
>>> cylinder to
>>> another according to individual EGTs (which of course are caused by
>>> uneven air
>>> delivery through the non symmetric intake runners)?
>>>
>>> IIRC, EGT probes tend to fail by degrees, giving increasingly
>>> erroneous readings for a
>>> while until they quit altogether.  How does FADEC [allege?] to deal
>>> with partial
>>> failures of EGT probe?  Total failure?
>>>
>>> Inquiring minds need to know .... Jim S.
>>
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> --
> Jim Sower
> Crossville, TN; Chapter 5
> Long-EZ N83RT, Velocity N4095T
>
>
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