This weekend I had a chance to make some observations concerning the
previous discussion on the use of the cold switch and the injector backup
mode on my EC2 used with a 13B.

 

When idling, turning on the cold switch results in all four injectors
delivering fuel at the pulse width that was used by the primary injectors
before the cold switch was turned on.   

When idling, turning on the cold switch results in the staging data bit
changing from indicating operation at MAP below the staging threshold to
operation above the staging threshold even though the MAP is very low.

 

With the cold switch on, gradually increasing MAP results in a gradually
increasing injector pulse width from idle to full throttle with no
discontinuity when the staging threshold is crossed.

 

Turning off the power to either the primary or secondary injectors has no
effect on the pulse width applied to the injectors or the status of the
staging data bit.

 

Based on the above observations, it appears that the EC2 does not need to
know whether or not power is being sent to the injectors.  Regardless of the
MAP at the time, turning on the cold switch results in the EC2 operating
with all four injectors as if the MAP was above the staging threshold but
with a pulse width appropriate for only two injectors being used.

 

My statements below concerning the cold switch position appear to be in
error.  The position of the Cold Switch is not one of the things contained
in the data log captured from the EC2 so that piece of data was from my
memory which is poor at best.  Sorry Bob.

 

I probably should have maintained the "Avoid reading.." subject line.  

Steve Boese

 




From:

Steven Boese <sboese@uwyo.edu>


Subject:

RE: [FlyRotary] Re: Below staging


Date:

Mon, 6 Jul 2009 00:24:28 -0600


To:

"'Rotary motors in aircraft'" <flyrotary@lancaironline.net>

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Bob,

In contrast to when the primary injector power is off, when the
secondary injectors are turned off and the cold switch on, the EC2
indicates staging is taking place normally at the staging threshold, in
my case at about 20 inches MAP. The engine doesn't go lean after
staging is indicated, however. When idling with the secondary injectors
turned off and the cold switch on, the EC2 indicates no staging has
taken place. Of course, what the EC2's staging data bit is telling the
outside world and what The EC2 is actually doing may be two different
things. Steve Boese