X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao104.cox.net ([68.230.241.42] verified) by logan.com (CommuniGate Pro SMTP 5.2.12) with ESMTP id 3501461 for flyrotary@lancaironline.net; Thu, 19 Feb 2009 16:01:13 -0500 Received-SPF: none receiver=logan.com; client-ip=68.230.241.42; envelope-from=alventures@cox.net Received: from fed1rmimpo03.cox.net ([70.169.32.75]) by fed1rmmtao104.cox.net (InterMail vM.7.08.02.01 201-2186-121-102-20070209) with ESMTP id <20090219210038.GQEE16134.fed1rmmtao104.cox.net@fed1rmimpo03.cox.net> for ; Thu, 19 Feb 2009 16:00:38 -0500 Received: from BigAl ([72.192.133.251]) by fed1rmimpo03.cox.net with bizsmtp id Hx0d1b0075RcKeo04x0dS7; Thu, 19 Feb 2009 16:00:37 -0500 X-Authority-Analysis: v=1.0 c=1 a=0sqxi1q0Ip8A:10 a=uik1YZiLepIA:10 a=pGLkceISAAAA:8 a=N8B9JuSIAAAA:8 a=ayC55rCoAAAA:8 a=CzjZfWBOAAAA:8 a=arxwEM4EAAAA:8 a=QdXCYpuVAAAA:8 a=7g1VtSJxAAAA:8 a=kviXuzpPAAAA:8 a=Ia-xEzejAAAA:8 a=nUuTZ29dAAAA:8 a=9Y17E0OA3HUzP5OmjWMA:9 a=l01D9mIX2nEPcGx9GKMA:7 a=1reHpBMTvRzfMVEjjLcpJOpN3wkA:4 a=gi0PWCVxevcA:10 a=MSl-tDqOz04A:10 a=EzXvWhQp4_cA:10 a=sSKeJDWgmUfkMzGqsMcA:9 a=pJHt5RPUplBw12Xdb3QA:7 a=Tt1fBvn_4BqpFqRekyZXHcETMYkA:4 a=37WNUvjkh6kA:10 X-CM-Score: 0.00 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: Staging Bog and Lean mixture Date: Thu, 19 Feb 2009 13:01:19 -0800 Message-ID: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0006_01C99292.288ADF00" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6838 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 In-Reply-To: Thread-Index: AcmSzYVaNpLDmvDCS4Sx3y2DX7tTLQABWSsg Importance: Normal This is a multi-part message in MIME format. ------=_NextPart_000_0006_01C99292.288ADF00 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable I hate to bring math into this:-), but at the speed the air is going in = the runner at the stage point, we're talking a few milliseconds even if the injector is 2 ft away. Not likely to be a noticeable contributor. =20 But speaking of swapping which set gets staged, that's what I do - I = stage the primary (the ones in the ports). I found that the engine ran = smoother at idle running on the secondary only - which on mine are about a foot = from the port. It was an easy swap on the 20B version of the EC2 with the external staging relay. =20 However; there was a time when I also occasionally experienced a mild = 'Bog'. It was when I had the stage point set at about 17", and occasionally = crossed that point during high altitude cruise. For a long time couldn't figure = out what it was (even posed the question here and didn't get an answer). Finally realized I was operating near the stage point, and that was it. Lowered the stage point, retuned; and now have no clue when it is = crossing that point during operation. =20 Al G =20 Subject: [FlyRotary] Re: Staging Bog and Lean mixture =20 David,=20 =20 With the time lag at the staging point (as Tracy described), do you = think it would help to switch the locations of the injectors and use the = injectors that are at the front-end of runners as the primaries and the ones in = the ports as the secondaries? I'm thinking that the secondaries would then = have a little extra time to start flowing before the mixture provided by the primary injectors is cut in half. I'm guessing that some of the bog may = be caused by the secondaries being located at the other end of the runners? Switching the injectors around may minimize the bog effect? =20 =20 Mark S. =20 On Thu, Feb 19, 2009 at 1:43 PM, David Leonard = wrote: For me (and probably many others), there is the additional factor that = my secondaries are at the end of the runners while the primaries are in on = the engine block. That means there is a slight delay in the getting the = fuel from the secondaries. I do compensate a little by turning up the = mixture a little on the first couple of bins above the staging point. Helps, but = cant fix the problem all together. =20 --=20 David Leonard Turbo Rotary RV-6 N4VY http://N4VY.RotaryRoster.net =20 http://RotaryRoster.net =20 On Thu, Feb 19, 2009 at 8:59 AM, Ed Anderson wrote: Ok, thanks for the explanation, Tracy. Makes sense to me. So the fuel increase with the secondaries coming on line during staging trails the shut-off of fuel on the primary injectors by some X amount. = So if I visualize it correctly I would see the fuel flow coming out of the secondaries increase as a ramp function compared to the step function = shut off of the primaries. All happening in milliseconds or less of course. Well, heck, all you have to do is calculate the cross over point where = the ramp function of the secondary meets the primary step function just as = it closes and then start the secondary injectors to opening before the primaries are closed. How, you do that - given all the interacting variables, I haven't any ideal - but sounds simple to me (in concept). = I AM kidding {:>) {:>) I think I'll just stick with my current technique as it seems to do the = job. By the way, here is an interesting patient perhaps related to the topic United States Patent 7475671 A method for compensating fuel injection timing when a torque signal or throttle command indicates that a transient operation is about to = transpire. The control adjusts the fuel injection timing in advance of the = transient operation to prevent loss of torque due to change in combustion phase position. During engine operation in pre-mix mode of combustion, rapid changes in fueling quantity can affect the combustion angle as well as = the temperature in the combustion chamber, causing late or early combustion phasing. The present invention anticipates a change in combustion = phasing by sensing a change in demanded fueling rate. The Engine Control Module = (ECM) then applies a nest of algorithms to advance fuel injection timing = during acceleration or to shorten ignition delay for deceleration by retarding = fuel injection timing. As the engine returns to steady state operation, the compensation in injection timing is progressively reduced to zero. http://www.freepatentsonline.com/7475671.html The phrase I like best in the abstract is ...applies a nest of = algorithms .. (sounds like a snake's nest to me {:>)). Ed Ed Anderson Rv-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com http://www.andersonee.com =20 http://www.dmack.net/mazda/index.html http://www.flyrotary.com/ http://members.cox.net/rogersda/rotary/configs.htm#N494BW From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Tracy Crook Sent: Thursday, February 19, 2009 10:48 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Staging Bog and Lean mixture Hi Ed, The method you used will work fine for eliminating the staging = bog. There have been enough comments on this subject so I might as well get = into some of the underlying causes. I mentioned before that it was related to the difference in turn-on and turn-off times of the injectors. The turn-on time is slower than the = turn off time, especially with the snubber mod which speeds up turn-off. = So, at staging point, the injector pulse width ( IPW ) is cut in half at = the same time as the controller enables the secondary injectors. If the = t-on and t-off times were equal, the injected fuel would be almost the same = as just before staging. BUT, the actual time the injectors are turned on = is less than 1/2 of what it was because a higher percentage of the IPW is = used up in the t-on injector delay , result is a lean condition. When the throttle is advanced more, the IPW gets longer and so the percentage of = IPW "wasted" in the t-on delay is less and the mixture returns to normal. If the staging point is made at a higher manifold pressure (and longer = IPW), the effect is not as great and that's why tuning out the "bog" is = easier. This describes the results with the same flow rate injectors in both = primary and secondary injectors. When different flow rates are used, the = picture gets more complicated. Mode 6 (staging flow rate differential) is even more important in these cases. That's why I now ask for what injectors = are used so I can roughly pre-set Mode 6 to make tuning it easier. Also a factor in how difficult the bog is to tune out is the setting of = Mode 2 (Injection Dynamic Range) but that is a longer subject. Suffice it = to say that setting Mode 6 and 2 up prior to MAP tuning in Mode 1 will make your life easier. Hope this helps in understanding what is going on. Tracy On Tue, Feb 17, 2009 at 5:45 PM, Ed Anderson wrote: Tracy, for what it's worth, I also see the leaning of the mixture at the staging point which happens to also coincide with the staging "bog". I never knew what was causing the bog and since I don't fly there nor encounter if during flight, it's never really bothered other than = wondering about what was causing it. Once I had a screen display to watch the bin pointer, the staging point = and the air/fuel mixture on the same screen, all at the same time, it became very clear that leaning of the mixture (or at least that is the = indication of air/fuel ratio indicator) is happening. As my bin pointer moves from the hump at the idle (low rpm) region, it = jumps from the low rpm map to the high power/manifold pressure chart above bin = 64 - not staged yet. Still no bog, but as it moves a few bins higher the air/fuel indicator dives from rich side to off the bottom of the scale = lean and the bog begins. At this point my staging sign goes from 2 injectors = to 4 injectors indicating that the EC2 has signaled staging. It last for = approx 3-5 bins (memory's a bit vague here) before the A/F indicator comes back = up the scale. So something is causing a lean condition. I always = speculated that it had something to do with the air/fuel mixture in the secondaries making the transition from "dry" to wet - but couldn't quite convince myself. The only way I have been able to eliminate the bog is to increase the richness of that region (3-4 bins) to approx 80-90 (out of 255) which is = not really a rich setting, but it works and has eliminated the bog. I = enrich each bin's bar watching the A/F indicator as soon as it stops going completely off the lean end of the scale, I stop and that seems to work = for me. Ed Ed Anderson Rv-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com http://www.andersonee.com =20 http://www.dmack.net/mazda/index.html http://www.flyrotary.com/ http://members.cox.net/rogersda/rotary/configs.htm#N494BW __________ Information from ESET NOD32 Antivirus, version of virus = signature database 3267 (20080714) __________ The message was checked by ESET NOD32 Antivirus. http://www.eset.com =20 -- Homepage: http://www.flyrotary.com/ Archive and UnSub: http://mail.lancaironline.net:81/lists/flyrotary/List.html =20 ------=_NextPart_000_0006_01C99292.288ADF00 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

I hate to bring math into = thisJ, but at the = speed the air is going in the runner at the stage point, we’re talking a few milliseconds even if the injector is 2 ft away. Not likely to be a = noticeable contributor.

 

But speaking of swapping which = set gets staged, that’s what I do – I stage the primary (the ones in = the ports).  I found that the engine ran smoother at idle running on = the secondary only – which on mine are about a foot from the port. It = was an easy swap on the 20B version of the EC2 with the external staging = relay.

 

However; there was a time when I = also occasionally experienced a mild ‘Bog’.  It was when I had the stage = point set at about 17”, and occasionally crossed that point during high altitude cruise.  For a long time couldn’t figure out what it = was (even posed the question here and didn’t get an answer).  = Finally realized I was operating near the stage point, and that was it.  = Lowered the stage point, retuned; and now have no clue when it is crossing that = point during operation.

 

Al G

 


Subject: [FlyRotary] Re: = Staging Bog and Lean mixture

 

David,

 

With the time lag at the staging point (as = Tracy described), do you think it would help to switch the locations of = the injectors and use the injectors that are at the front-end of = runners as the primaries and the ones in the ports as the secondaries?  I'm = thinking that the secondaries would then have a little = extra time to start flowing before the mixture provided by the primary injectors is = cut in half.  I'm guessing that some of the bog may be caused by the secondaries being located at the other end of the runners?  Switching the injectors around may minimize the bog effect?   

 

Mark S.   

On Thu, Feb 19, 2009 at 1:43 PM, David = Leonard <wdleonard@gmail.com> = wrote:

For me (and probably many others), there is = the additional factor that my secondaries are at the end of the runners = while the primaries are in on the engine block.  That means there is a slight = delay in the getting the fuel from the secondaries.  I do compensate a = little by turning up the mixture a little on the first couple of bins above the = staging point.  Helps, but cant fix the problem all = together.

 

--
David Leonard

Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net
http://RotaryRoster.net

On Thu, Feb 19, 2009 at 8:59 AM, Ed Anderson = <eanderson@carolina.rr.com> wrote:

Ok, thanks for the explanation, Tracy. =  Makes sense to me.


So the fuel increase with the secondaries coming on line during = staging
trails the shut-off of fuel on the primary injectors by some  X = amount.  So
if I visualize it correctly I would see the fuel flow coming out of = the
secondaries increase as a ramp function compared to the step function = shut
off of the primaries. All happening in milliseconds or less of = course.

Well, heck, all you have to do is calculate the cross over point where = the
ramp function of the secondary meets the primary step function just as = it
closes and then start the secondary injectors to opening before the
primaries are closed.  How, you do that - given all the = interacting
variables, I haven't any ideal - but sounds simple to me (in concept). =  I AM
kidding {:>) {:>)

I think I'll just stick with my current technique as it seems to do the = job.


By the way, here is an interesting patient perhaps related to the = topic

United States Patent 7475671

A method for compensating fuel injection timing when a torque signal = or
throttle command indicates that a transient operation is about to = transpire.
The control adjusts the fuel injection timing in advance of the = transient
operation to prevent loss of torque due to change in combustion = phase
position. During engine operation in pre-mix mode of combustion, = rapid
changes in fueling quantity can affect the combustion angle as well as = the
temperature in the combustion chamber, causing late or early = combustion
phasing. The present invention anticipates a change in combustion = phasing by
sensing a change in demanded fueling rate. The Engine Control Module = (ECM)
then applies a nest of algorithms to advance fuel injection timing = during
acceleration or to shorten ignition delay for deceleration by retarding = fuel
injection timing. As the engine returns to steady state operation, = the
compensation in injection timing is progressively reduced to zero.
http://www.freepatentsonline.com/7475671.html


The phrase I like best in the abstract is ...applies a nest of = algorithms ..
(sounds like a snake's nest to me {:>)).

From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On
Behalf Of Tracy Crook
Sent: Thursday, February 19, 2009 10:48 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Staging Bog and Lean mixture


Hi Ed, The method you used will work fine for eliminating the staging = bog.

There have been enough comments on this subject so I might as well get = into
some of the underlying causes.

I mentioned before that it was related to the difference in turn-on = and
turn-off times of the injectors.  The turn-on time is slower than = the turn
off time, especially with the snubber mod which speeds up turn-off. =   So,
at staging point, the injector pulse width ( IPW )  is cut in half = at the
same time as the controller enables the secondary injectors.  If = the t-on
and t-off times were equal, the injected fuel would be almost the same = as
just before staging.   BUT, the actual time the injectors are = turned on is
less than 1/2 of what it was because a higher percentage of the IPW is = used
up in the t-on injector delay ,  result is a lean condition.   = When the
throttle is advanced more, the IPW gets longer and so the percentage of = IPW
"wasted" in the t-on delay is less and the mixture returns to = normal.

If the staging point is made at a higher manifold pressure (and longer = IPW),
the effect is not as great and that's why tuning out the "bog" = is easier.

This describes the results with the same flow rate injectors in both = primary
and secondary injectors.   When different flow rates are used, the = picture
gets more complicated.   Mode 6 (staging flow rate differential) is = even
more important in these cases.  That's why I now ask for what = injectors are
used so I can roughly pre-set Mode 6 to make tuning it easier.

Also a factor in how difficult the bog is to tune out is the setting of = Mode
2 (Injection Dynamic Range) but that is a longer subject.   Suffice = it to
say that setting Mode 6 and 2 up prior to MAP tuning in Mode 1 will = make
your life easier.

Hope this helps in understanding what is going on.

Tracy

On Tue, Feb 17, 2009 at 5:45 PM, Ed Anderson <eanderson@carolina.rr.com>
wrote:
Tracy, for what it's worth, I also see the leaning of the mixture at = the
staging point which happens to also coincide with the staging = "bog".
I never knew what was causing the bog and since I don't fly there = nor
encounter if during flight, it's never really bothered other than = wondering
about what was causing it.

Once I had a screen display to watch the bin pointer, the staging point = and
the air/fuel mixture on the same screen, all at the same time, it = became
very clear that leaning of the mixture (or at least that is the = indication
of air/fuel ratio indicator) is happening.

As my bin pointer moves from the hump at the idle (low rpm) region, it = jumps
from the low rpm map to the high power/manifold pressure chart above bin = 64
- not staged yet.  Still no bog, but as it moves a few bins higher =   the
air/fuel indicator dives from rich side to off the bottom of the scale = lean
and the bog begins. At this point my staging sign goes from 2 injectors = to 4
injectors indicating that the EC2 has signaled staging.  It last = for approx
3-5 bins (memory's a bit vague here) before the A/F indicator comes back = up
the scale.  So something is causing a lean condition.  I = always speculated
that it had something to do with the air/fuel mixture in the = secondaries
making the transition from "dry" to wet - but couldn't quite = convince
myself.

The only way I have been able to eliminate the bog is to increase = the
richness of that region (3-4 bins) to approx 80-90 (out of 255) which is = not
really a rich setting, but it works and has eliminated the bog.  I = enrich
each bin's bar watching the A/F indicator as soon as it stops going
completely off the lean end of the scale, I stop and that seems to work = for
me.

Ed

Ed Anderson
Rv-6A N494BW Rotary Powered
Matthews, NC
eanderson@carolina.rr.com
http://www.andersonee.com
http://www.dmack.net/mazda/index.html
http://www.flyrotary.com/
http://members.cox.net/rogersda/rotary/configs.htm#N494= BW
<http://members.cox.net/rogersda/rotary/configs.htm&= gt;
 <http://www.dmack.net/mazda/index.html>


__________ Information from ESET NOD32 Antivirus, version of virus signature
database 3267 (20080714) __________

The message was checked by ESET NOD32 Antivirus.

http://www.eset.com


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