X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from rv-out-0506.google.com ([209.85.198.228] verified) by logan.com (CommuniGate Pro SMTP 5.2.12) with ESMTP id 3501648 for flyrotary@lancaironline.net; Thu, 19 Feb 2009 18:13:34 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.85.198.228; envelope-from=wdleonard@gmail.com Received: by rv-out-0506.google.com with SMTP id b25so687722rvf.7 for ; Thu, 19 Feb 2009 15:12:58 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:message-id:subject:from:to:content-type; bh=zMF1MXgHflMFF83KyFpedJq3LD/+sxqt+lgFyWbVM5k=; b=Rwi7L9eeo1isCDckjJCs31BsZiCshaoNAc+LxJ4GyclRDWvoCUKcwuEJvyvB0Fk7on eEfxBqqRr1vzoxLMzwkv45ZTtvmScvwsTwaI6q2ftHwzh3Vlif4QiVXe5ena7R8ePA2A 9F9guMxbwLYE7Sqs4dsOVDzkmSU9XIdCGE3Sw= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; b=QWEstH7EzYO79sUjxOMTH1xEj244tVHTy8qXbHoNMrmLJEZFsq3AxLA8UylQihb4wi uiGxPuiI/NA8k3Vno+M4ITnTEONBsZCVy9F+gqtZ9AzFloQ96qAB9OUKLU6Gain2cX9G VxkbFQ32VDDMENODWHorX9pRxSClQS8IcxQaI= MIME-Version: 1.0 Received: by 10.141.211.5 with SMTP id n5mr50413rvq.106.1235085178700; Thu, 19 Feb 2009 15:12:58 -0800 (PST) In-Reply-To: References: Date: Thu, 19 Feb 2009 15:12:58 -0800 Message-ID: <1c23473f0902191512p65a66240hcadecb0cefadc3c@mail.gmail.com> Subject: Re: [FlyRotary] Re: Staging Bog and Lean mixture From: David Leonard To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=000e0cd14d665803d904634dad22 --000e0cd14d665803d904634dad22 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable Well, down at lower RPM the air is going to take longer to get throught the intake. Either way, there is at least enough volume of air in the intake t= o account for 1 intake cycle for each rotor. That is 2 consecutive misfires and definately noticable as an engine skip. After adjusting the MAP table, I don't get a staging bog, so much as a skip. My engine runs about the same on either pair of injectors. At idle, switching from primaries to secondaries (ie. during run up) will cause a skip, but not switching from secondaries back to primaries. In cruise flight I get a little skip going either direction, I assume because there are a couple of cycles of over-rich running when heading down. Al's method of putting the primaries at the end of the runners obviously works fine. I have tested that configuration. There are some downsides especially for my set-up. Starting the engine took an extra second or 2 of cranking. My throttle body is not very air tight around the axle, so using the secondaries creates some fuel leakage there whenever the pressure in th= e intake is higher than ambient (this is the main reason why I currently use the primaries almost exclusively - too much hassle to replace the TB). Eve= n without forced air, the throttle body is a little inverted and a lot of fue= l drips or otherwise goes backward out of the intake system even when running at high power. My turbo plumbing catches it, but for a while I was n.a. an= d it made quite a mess of things. --=20 David Leonard Turbo Rotary RV-6 N4VY http://N4VY.RotaryRoster.net http://RotaryRoster.net On Thu, Feb 19, 2009 at 1:01 PM, Al Gietzen wrote: > I hate to bring math into thisJ, but at the speed the air is going in th= e > 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 =96 I st= age > the primary (the ones in the ports). I found that the engine ran smoothe= r > at idle running on the secondary only =96 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 occasiona= lly > 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 i= s > 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 inject= ors > 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 provide= d > by the primary injectors is cut in half. I'm guessing that some of the b= og > 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 > 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 t= he > 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 c= ant > 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 > 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 shu= t > 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 th= e > 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 th= e > 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 > 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 in= to > 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 tur= n > 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 i= s > less than 1/2 of what it was because a higher percentage of the IPW is us= ed > 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 I= PW > "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 pictur= e > 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 a= re > 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 wonderi= ng > about what was causing it. > > Once I had a screen display to watch the bin pointer, the staging point a= nd > 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 indicatio= n > 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 le= an > and the bog begins. At this point my staging sign goes from 2 injectors t= o > 4 > injectors indicating that the EC2 has signaled staging. It last for appr= ox > 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 speculate= d > 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 f= or > 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#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 > > > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: > http://mail.lancaironline.net:81/lists/flyrotary/List.html > > > > > --000e0cd14d665803d904634dad22 Content-Type: text/html; charset=windows-1252 Content-Transfer-Encoding: quoted-printable
Well, down at lower RPM the air is going to take longer to get through= t the intake.  Either way, there is at least enough volume of air in t= he intake to account for 1 intake cycle for each rotor.  That is 2 con= secutive misfires and definately noticable as an engine skip.  Af= ter adjusting the MAP table, I don't get a staging bog, so mu= ch as a skip.
 
My engine runs about the same on either pair of injectors.  At id= le, switching from primaries to secondaries (ie. during run up) will cause = a skip, but not switching from secondaries back to primaries.  In crui= se flight I get a little skip going either direction, I assume because ther= e are a couple of cycles of over-rich running when heading down.
 
Al's method of putting the primaries at the end of the runners obv= iously works fine.  I have tested that configuration.  There are = some downsides especially for my set-up.  Starting the engine took an = extra second or 2 of cranking.  My throttle body is not very air tight= around the axle, so using the secondaries creates some fuel leakage there = whenever the pressure in the intake is higher than ambient (this is the mai= n reason why I currently use the primaries almost exclusively - too much ha= ssle to replace the TB).  Even without forced air, the throttle body i= s a little inverted and a lot of fuel drips or otherwise goes backward out = of the intake system even when running at high power.  My turbo plumbi= ng catches it, but for a while I was n.a. and it made quite a mess of thing= s.
 
--
David Leonard

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


On Thu, Feb 19, 2009 at 1:01 PM, Al Gietzen <A= LVentures@cox.net> wrote:

I hate to bring math into this<= /span>J, 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 =96 I stage the primary (the ones in = the ports).  I found that the engine ran smoother at idle running on t= he secondary only =96 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 h= ad the stage point set at about 17", and occasionally crossed that poi= nt during high altitude cruise.  For a long time couldn't figure o= ut 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

<= span style=3D"FONT-SIZE: 12pt"> 

<= span style=3D"FONT-SIZE: 12pt">David,

<= span style=3D"FONT-SIZE: 12pt"> 

<= span style=3D"FONT-SIZE: 12pt">With the time lag at the staging point (as T= racy 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 runn= ers as the primaries and the ones in the ports as the secondaries?  I&= #39;m thinking that the secondaries would then have a little extr= a time to start flowing before the mixture provided by the primar= y injectors is cut in half.  I'm guessing that some of the bo= g may be caused by the secondaries being located at the other end of the ru= nners?  Switching the injectors around may minimize the= bog effect?   

<= span style=3D"FONT-SIZE: 12pt"> 

Mark= S.   

<= span style=3D"FONT-SIZE: 12pt">On Thu, Feb 19, 2009 at 1:43 PM, David Leona= rd <wdleonard@g= mail.com> wrote:

<= span style=3D"FONT-SIZE: 12pt">For me (and probably many others), there is = the additional factor that my secondaries are at the end of the runners whi= le the primaries are in on the engine block.  That means there is a sl= ight delay in the getting the fuel from the secondaries.  I do compens= ate 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 togethe= r.

<= span style=3D"FONT-SIZE: 12pt"> 

-- <= br>David Leonard

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

<= span style=3D"FONT-SIZE: 12pt">On Thu, Feb 19, 2009 at 8:59 AM, Ed Anderson= <eanders= on@carolina.rr.com> wrote:

<= span style=3D"FONT-SIZE: 12pt">Ok, thanks for the explanation, Tracy.  = ;Makes sense to me.


So the fuel increase with the secondaries co= ming 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.
<= br>Well, heck, all you have to do is calculate the cross over point where t= he
ramp function of the secondary meets the primary step function just a= s it
closes and then start the secondary injectors to opening before the
prim= aries are closed.  How, you do that - given all the interacting
var= iables, I haven't any ideal - but sounds simple to me (in concept). &nb= sp;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 inte= resting patient perhaps related to the topic

United States Patent 74= 75671

A method for compensating fuel injection timing when a torque signal or=
throttle command indicates that a transient operation is about to trans= pire.
The control adjusts the fuel injection timing in advance of the tr= ansient
operation to prevent loss of torque due to change in combustion phase
po= sition. During engine operation in pre-mix mode of combustion, rapid
cha= nges 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 b= y
sensing a change in demanded fueling rate. The Engine Control Module (= ECM)
then applies a nest of algorithms to advance fuel injection timing duringacceleration or to shorten ignition delay for deceleration by retarding f= uel
injection timing. As the engine returns to steady state operation, t= he
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 {:>)).

<= span style=3D"FONT-SIZE: 12pt">From: Rotary motors in aircraft [mailto:flyrotary@lanc= aironline.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.<= br>
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 wa= s related to the difference in turn-on and
turn-off times of the injecto= rs.  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 h= alf 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 asjust 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 I= PW is used
up in the t-on injector delay ,  result is a lean condition.   Wh= en the
throttle is advanced more, the IPW gets longer and so the percent= age 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 pic= ture
gets more complicated.   Mode 6 (staging flow rate differentia= l) 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 makeyour life easier.

Hope this helps in understanding what is going on= .

Tracy

On Tue, Feb 17, 2009 at 5:45 PM, Ed Anderson <eanderson@caroli= na.rr.com>
wrote:
Tracy, for what it's worth, I also see the leaning of the mix= ture at the
staging point which happens to also coincide with the stagin= g "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 wonde= ring
about what was causing it.

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

As my bin pointer move= s 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 &nb= sp; 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 a= pprox
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 secondariesmaking 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 no= t
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 sto= ps 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
Matt= hews, NC
= eanderson@carolina.rr.com
http://www.anderso= nee.com
http://www.dmack.net/mazda/index.html
http://www.flyrotary.com/
http://members.cox.net/rogersda/rotary/configs.htm#N494BW<= br><http://members.cox.net/rogersda/rotary/configs.htm>
 <http://www.dmack.net/mazda/index.html>


<= /p>

____= ______ Information from ESET NOD32 Antivirus, version of virus signaturedatabase 3267 (20080714) __________

The message was checked by ESET NOD32 Antivirus.

http://www.eset.com


= --
Homepage:  http://www.flyrotary.com/
Archive and UnSub:   http://mail.lancaironline.net:81/li= sts/flyrotary/List.html


=

<= span style=3D"FONT-SIZE: 12pt"> 




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