REFLECTOR: Carburated Auto engine

[Dennis Martin]

I am installing two Tech 3 systems on my odd-fire Chevy V-6.   Each 
has multiple built-in redundancy modes, often called back up or "limp 
home" modes.  Still, if one goes out, you gotta land fast.  I feel 
safer with two computers on circuits A and B; if one computer suffers 
total failure, I can easily make the nearest airport and land with 
power.

Dennis Martin
FG 173

>Same value system here.
>
>I put an Autronic on the Franklin.  And since I'm paranoid, I came 
>up with my own backup system.  Two injectors per cylinder.  The 
>backup system runs on a small SLA battery about the size of my fist.
>
>According to my math, as long as the system is steady state, it will 
>run the engine for a couple hundred hours.
>The backup fuel injection is constant flow, set by a needle valve. 
>Normally the only power consumed is running the CPU (10mA at 20 
>MHz), and the sensors (less than 8mA).  When the parameters change, 
>the stepper motor is turned on to re-adjust the valve.
>
>There's no off switch.  The CPU in quiescent mode consumes about 15 
>uA (20KHz).  That's .000015 amps at 3.3 volts DC.  The SLA battery 
>is charged from the airplane whenever the main Autronic EFI switch 
>is on.
>
>The CPU when running at 20KHz occasionally (several times a second) 
>turns on the sensor to check if the crank is turning.  If it is, and 
>the main EFI power bus is off, then it goes into active mode and 
>assumes the backup functions.
>
>I have an overhead switch to turn on/off the main injector power in 
>case of emergency, or to test the system.
>
>Of course the magneto is my ignition backup.
>
>-----Original Message-----
>From: reflector-bounces at tvbf.org 
>[mailto:reflector-bounces at tvbf.org]On Behalf Of NMFlyer1 at aol.com
>Sent: Tuesday, November 23, 2004 9:20 AM
>To: reflector at tvbf.org
>Subject: Re: REFLECTOR: Carburated Auto engine
>
>I had the same options when I designed my V-6 powerplant.  There are 
>plenty of computer programs (specially for the LT1) that tuning and 
>monitoring the EFI system are relatively easy. My sole concern of 
>the EFI system is the main processor.
>
>  Most modern ECM's do have a "limp home mode".... that many don't 
>completely understand. The "limp home mode" only works if the system 
>has malfunctions/failures in the sensors.  IT DOES NOT HAVE A BACKUP 
>IF THE ECM ITSELF FAILS!!
>Since I have had 3 seperate computer failures, on 3 different types 
>of automobiles, all without warning. That was unacceptable.
>
>There is no doubt that a computerized EFI would be the most 
>efficient. It was just my choice not to trust the processor.
>
>By far, the least efficient would be the carb.  But; they are the 
>good ole technology.
>
>I chose the multi port Airflow Performance system for my own 
>application, but I believe the Ellison Throttle body is a good 
>choice too.
>
>All the best,    Kurt
>
>
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