X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from cdptpa-omtalb.mail.rr.com ([75.180.132.122] verified) by logan.com (CommuniGate Pro SMTP 5.4c2) with ESMTP id 4900826 for flyrotary@lancaironline.net; Wed, 09 Mar 2011 12:12:35 -0500 Received-SPF: pass receiver=logan.com; client-ip=75.180.132.122; envelope-from=eanderson@carolina.rr.com Return-Path: X-Authority-Analysis: v=1.1 cv=tLsyj04/L/SH/N6p42ldY6jXDYWe4pX5hAm6uRA1LKo= c=1 sm=0 a=M5-eFe1jdyUA:10 a=rPkcCx1H5rrOSfN0dPC7kw==:17 a=7g1VtSJxAAAA:8 a=Ia-xEzejAAAA:8 a=WI0sdL2H1vx9zEO-nekA:9 a=6lfaqQZGA9suDmPiosEA:7 a=LH4u8Vt1KiOyp6GY3slzPsljVMYA:4 a=wPNLvfGTeEIA:10 a=Qa1je4BO31QA:10 a=yMhMjlubAAAA:8 a=zyFgd6TOF0an90HqFKcA:9 a=ggRmNROzNUFOkExLpM0A:7 a=nS_ijkkZrBoYDrWHrgjFMRu8lz4A:4 a=EzXvWhQp4_cA:10 a=rPkcCx1H5rrOSfN0dPC7kw==:117 X-Cloudmark-Score: 0 X-Originating-IP: 174.110.167.5 Received: from [174.110.167.5] ([174.110.167.5:51633] helo=EdPC) by cdptpa-oedge02.mail.rr.com (envelope-from ) (ecelerity 2.2.3.46 r()) with ESMTP id F4/3D-05134-FD4B77D4; Wed, 09 Mar 2011 17:11:59 +0000 Message-ID: <1E86A409EEC644C486662F1A9C4BE5FE@EdPC> From: "Ed Anderson" To: "Rotary motors in aircraft" References: In-Reply-To: Subject: Re: [FlyRotary] more staging and tuning Date: Wed, 9 Mar 2011 12:11:33 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_001D_01CBDE53.21489D90" X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 14.0.8117.416 X-MimeOLE: Produced By Microsoft MimeOLE V14.0.8117.416 This is a multi-part message in MIME format. ------=_NextPart_000_001D_01CBDE53.21489D90 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Fascinating, Steve I presume the perturbation we see in the right side of left plot (Tuning = Plot1.jpg) as you decrease engine rpm (and I see a tweak of the manual = mixture control -- perhaps to keep the engine from dying?) - the O2 = sensor bobbing between rich and lean. I do not see that pertubation on = the right plot - is this (bobbing between rich and lean) due to the = controller causing the injectors to actually cut off (not open) due to = the 1.2 msec delay not being compensated for???=20 If one had the controller map math, it might be possible to add the = "1.2msec" of fuel missing by increasing the MAP value in each bin??? = However, I guess (even if possible) it would be easier to compensate by = using your method 1 or 2.=20 Good work, really appreciate you sharing it with us Ed From: Steven W. Boese=20 Sent: Wednesday, March 09, 2011 11:19 AM To: Rotary motors in aircraft=20 Subject: [FlyRotary] more staging and tuning For those of you who made it to the end of my long post a couple of days = ago where only two of the three methods I've used in dealing with = injector lag were described, here is the third: =20 The two methods of dealing with injector lag described previously could = be considered as working around the basic problem more than a solution = to it. Although the best way to deal with the injector lag effect might = be to compensate for it in the controller firmware, we do not have that = ability in the field. Purely as a proof of concept exercise, 1.2 ms was = always added to each injector pulse by the addition of hardware. The = results are shown in the attached data plots. The data was collected = directly from the EC2's into an IPAQ. =20 Plot 1 shows two idle to full throttle back to idle sequences. Both = sequences were generated after adjusting modes 3 and 2, but leaving the = rest of the EC2 parameters and the MAP table at factory defaults. Data = for the manual mixture adjustment and the table value are included to = show that no changes in these parameters occurred during the power = sweeps. The green line near the bottom labeled "staged x 10" is the = logic signal from the EC2 that is "1" when the MAP is below the staging = threshold and "0" when the MAP is above the staging threshold. These = values were multiplied by ten so the staging transitions would be easy = to pick out in the plots. The data on the left is with the normal = injector pulses while the data on the right is with the addition of 1.2 = ms to each injector pulse. In each case, the oxygen sensor shows a = somewhat rich mixture just prior to staging. With MAP above the staging = threshold, the O2 sensor shows a change to a lean mixture for the normal = injector pulse whereas there is no staging mixture change when 1.2 ms = has been added to each pulse. It is important to understand that the = 1.2 ms is added to the injector pulses at all times, not just after = crossing the staging threshold. A decrease in RPM is also seen when the = O2 sensor goes lean when the normal pulses are used. =20 =20 It could be argued that the mixture was more rich to begin with for the = sequence with the added 1.2 ms and that is true. For this reason I've = included plot 2. This is a plot of data resulting from a previous = similar experiment with the added 1.2 ms but starting with a leaner = condition. The prop loading was also different, but the mixture is = consistent throughout the power range. Again, this is with all factory = defaults except for modes 3 and 2. It should also be noted that the MAP = was limited to about 23 inches due to the density altitude of over 7200 = ft at this location. =20 The simplified tuning as a result of adding the injector lag time to the = injector pulses has been demonstrated with my engine stand on the ground = and with my plane on the ground as well as in flight. The favorable = effect of this addition is seen not only on staging but also possibly in = the low power high RPM descent flight regime. Although I don't have a = lot of time in the plane yet with this set up, the results so far seemed = to be worth reporting. =20 Steve Boese RV6A 1986 13B NA RD1A EC2 =20 -------------------------------------------------------------------------= ------- -- Homepage: http://www.flyrotary.com/ Archive and UnSub: = http://mail.lancaironline.net:81/lists/flyrotary/List.html ------=_NextPart_000_001D_01CBDE53.21489D90 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Fascinating, Steve
 
I presume the perturbation we see=20 in the right side of left plot (Tuning Plot1.jpg)  as you decrease = engine=20 rpm (and I see a tweak of the manual mixture control -- perhaps to keep = the=20 engine from dying?) - the O2 sensor bobbing between rich and lean.  = I do=20 not see that pertubation on the right plot -  is this (bobbing = between=20 rich and lean)  due to the controller causing the injectors to = actually cut=20 off (not open) due to the 1.2 msec delay not being compensated for???=20
 
If one had the controller map math, it = might be=20 possible to add the "1.2msec" of fuel missing by increasing the MAP = value in=20 each bin???  However,  I guess (even if possible) it = would be=20 easier to compensate by using your method 1 or 2.
 
Good work, really appreciate you sharing it with = us
 
Ed
 
 

From: Steven W. Boese
Sent: Wednesday, March 09, 2011 11:19 AM
To: Rotary motors in = aircraft
Subject: [FlyRotary] more staging and = tuning

For those of you who made it to the end of my = long post a=20 couple of days ago where only two of the three methods I=92ve used in = dealing with=20 injector lag were described, here is the third:

 

The two methods of dealing with injector lag = described=20 previously could be considered as working around the basic problem more = than a=20 solution to it.  Although the best way to deal with the injector = lag effect=20 might be to compensate for it in the controller firmware, we do not have = that=20 ability in the field.  Purely as a proof of concept exercise, 1.2 = ms was=20 always added to each injector pulse by the addition of hardware.  = The=20 results are shown in the attached data plots.  The data was = collected=20 directly from the EC2=92s into an IPAQ.

 

Plot 1 shows two idle to full throttle back to = idle=20 sequences.  Both sequences were generated after adjusting modes 3 = and 2,=20 but leaving the rest of the EC2 parameters and the MAP table at factory=20 defaults.  Data for the manual mixture adjustment and the table = value are=20 included to show that no changes in these parameters occurred during the = power=20 sweeps.  The green line near the bottom labeled =93staged x 10=94 = is the logic=20 signal from the EC2 that is =931=94 when the MAP is below the staging = threshold and=20 =930=94 when the MAP is above the staging threshold.  These values = were=20 multiplied by ten so the staging transitions would be easy to pick out = in the=20 plots.  The data on the left is with the normal injector pulses = while the=20 data on the right is with the addition of 1.2 ms to each injector = pulse. =20 In each case, the oxygen sensor shows a somewhat rich mixture just prior = to=20 staging.  With MAP above the staging threshold, the O2 sensor shows = a=20 change to a lean mixture for the normal injector pulse whereas there is = no=20 staging mixture change when 1.2 ms has been added to each pulse.  = It is=20 important to understand that the 1.2 ms is added to the injector pulses = at all=20 times, not just after crossing the staging threshold.  A decrease = in RPM is=20 also seen when the O2 sensor goes lean when the normal pulses are = used. =20

 

It could be argued that the mixture was more = rich to begin=20 with for the sequence with the added 1.2 ms and that is true.  For = this=20 reason I've included plot 2.  This is a plot of data resulting from = a=20 previous similar experiment with the added 1.2 ms but starting with a = leaner=20 condition.  The prop loading was also different, but the mixture is = consistent throughout the power range.  Again, this is with all = factory=20 defaults except for modes 3 and 2.  It should also be noted that = the MAP=20 was limited to about 23 inches due to the density altitude of over 7200 = ft at=20 this location.

 

The simplified tuning as a result of adding the = injector=20 lag time to the injector pulses has been demonstrated with my engine = stand on=20 the ground and with my plane on the ground as well as in flight.  = The=20 favorable effect of this addition is seen not only on staging but also = possibly=20 in the low power high RPM descent flight regime.  Although I = don=92t have a=20 lot of time in the plane yet with this set up, the results so far seemed = to be=20 worth reporting.

 

Steve=20 Boese

RV6A=20 1986 13B NA RD1A EC2

 

--
Homepage:  http://www.flyrotary.com/
Archive and=20 UnSub:  =20 http://mail.lancaironline.net:81/lists/flyrotary/List.html
------=_NextPart_000_001D_01CBDE53.21489D90--