Mailing List flyrotary@lancaironline.net Message #36102
From: Ed Anderson <eanderson@carolina.rr.com>
Subject: Re: [FlyRotary] Re: The truth??? / Injector flow rate mystery solved
Date: Sat, 10 Mar 2007 23:34:33 -0500
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Message
I follow that, Steve.
 
That sounds like a possible reason why my idle is so "sloppy" below 2000 rpm.  It acts like its overly rich but when I attempt to reduce the fuel ratio by reducing the mixture control the engine dies. So when I reduce the mixture and it drops the pulse duration below 2 milliseconds the engine dies - but 2 milliseconds provides too much fuel at idle. 
 
I wonder if Tracy now flying with a Renesis engine does not have this problem because I believe the primary injectors on it are around 250 cc/min compared to my 460 cc/min.  So nearly 1/2 the fuel flow per millisecond than my injectors.  So two milliseconds on the 250 cc/min injectors may be OK at idle but 2 milliseconds on 460 cc/min is just too much.
 
Thanks for pointing that out Steve.  All is becoming much clearer.
 
Ed
 
 
----- Original Message -----
Sent: Saturday, March 10, 2007 10:44 PM
Subject: [FlyRotary] Re: The truth??? / Injector flow rate mystery solved

Ed and George,

 

In my plane, at least, injector open times need to be less than 2 ms at idle and just above the staging point.  This is not possible with a minimum open time of 2 ms due to the delay on closing.  You can program the EC2 for less than 2 ms but the hardware is unable to do this.  That means that the problem can’t be fixed with software or programming different values in the map table.  A shorter close delay time is required unless you lower the flow rate of the injectors by changing the injector itself or lower the fuel pressure.  The injector open time is at least 2 ms or it doesn’t open at all.

 

Steve Boese

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