X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from exchange.carey.wa.edu.au ([118.82.44.212] verified) by logan.com (CommuniGate Pro SMTP 5.4.1) with ESMTPS id 5108313 for flyrotary@lancaironline.net; Tue, 30 Aug 2011 10:07:34 -0400 Received-SPF: none receiver=logan.com; client-ip=118.82.44.212; envelope-from=stevei@carey.asn.au Received: from exchange.carey.local ([10.10.0.5]) by exchange.carey.local ([10.10.0.5]) with mapi; Tue, 30 Aug 2011 22:06:54 +0800 From: To: Date: Tue, 30 Aug 2011 22:06:55 +0800 Subject: Re: [FlyRotary] Re: Freq analysis of Knock sensor? Thread-Topic: [FlyRotary] Re: Freq analysis of Knock sensor? Thread-Index: AcxnHhI2ndMoXBkHTKqJfFu2zKu6Hw== Message-ID: References: In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: multipart/alternative; boundary="_000_B27B6471A6AE418F9637E33760BFBF97careyasnau_" MIME-Version: 1.0 --_000_B27B6471A6AE418F9637E33760BFBF97careyasnau_ Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Hi Ed I've had the engine running 18months ago but have it off the fuse so I can = rotate the thing for sanding. I'm building a Glasair Super II RG. Just finishing the Slotted Flaps at pre= sent. Hoping to put her together and retest engine by early next year. Sorry, not much help for now. Cheers Steve On 30/08/2011, at 7:50 PM, Ed Anderson wrote: Hi Steve, My understanding (Lynn will probably correct me here) is that under normal = loads, temps and fuel the probability of detonation or knock in a rotary en= gine is pretty small due to the characteristics of its combustion chamber. = Now under boost, there is no question you can get into the detonation rang= e, so it would seem to me that a knock sensor would be of biggest benefit t= o those with forced induction. I , for one, would be very interested in what you find when you listen in. = Wonder whether you might be able to make an audio recording of what the sy= stems puts out - there are some interesting analytical tools as pointed out= by Finn and several others that might be interesting to run the data throu= gh. I presume you have the engine running - just not up to full power, yet? Ed From: stevei@carey.asn.au Sent: Tuesday, August 30, 2011 4:38 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Freq analysis of Knock sensor? Hi Ed My Renesis came with the knock sensor, but as you say the bandwidth of the = sensor is probably to wide. Having the sensor I built up a kit knock sensor amp and filters. But as we = recognise the knock of a rotor may sound vastly different from a piston. I plan to listen in when I get to full power ground runs. Problem being I don't want to punish my engine to hear what it sounds like = when its complaining! Cheers Steve Izett On 29/08/2011, at 10:36 PM, Ed Anderson wrote: A thought occurred to me. If anyone has a spectrum analyzer (Steve??) and = could obtain an Rotary Knock sensor - that perhaps determining the frequenc= y response of the knock sensor MIGHT indicate the frequency band pass requi= red. Although it is likely to be too broad to be much help if ( as likely)= they do the filtering through a bandpass filter within the engine CPU. Ed From: Ed Anderson Sent: Monday, August 29, 2011 9:54 AM To: Rotary motors in aircraft Subject: [FlyRotary] Not so Simple was Knock sensor was tune with ADI: [Fly= Rotary] Re: How to tune with ADI? As Tracy also indicated - in may cases, what initially appears simple - fr= equently turns out not to be the case, when you dive into the details. Another seemingly simple project I thought about, was to add a wide band O2= (WBO2) sensor option for the EFISM. This in order to provide more accurat= e info on the air/fuel ratio (although one could argue just how useful that= might be for our applications). While providing an algorithm for the different voltage input curve of the W= BO2 sensor (it is much more linear than the narrow band O2 sensor curve) is= straightforward, when you dive deeper you discover that: 1. For the wide band O2 sensor to provide accurate information the sensor = temperature must be held within a critical narrow range. 2. To do this properly, the WBO2 manufacturer either programs into the au= tomobile's CPU or provides a separate "control" chip that uses a PID (Prop= ortional, Integral, derivative) the control algorithm necessary to hold the= required critical temperature range. 3. Failure to hold this temp range renders the sensor output of questionab= le accuracy and will lead to degradation/failure of the sensor. 4. The PID temp control is much more complex than the algorithm required t= o read the output voltage So while I could add the WBO2 sensor - without the separate algorithm (or c= ontrol chip), the validity of the data is uncertain and likely misleading. = So no WBO2 option any time soon. Yet this project is much more straightforward than a knock sensor. Most au= tomobile engine manufactures can afford to do the research and they can spr= ead the cost over millions of engines sold. As you might imagine, the resu= lts of their R&D is considered proprietary information and seldom available= to the public. Ed From: Tracy Sent: Monday, August 29, 2011 9:24 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: How to tune with ADI? What Ed said. There is a knock sensor input on the EC3 but after finding = the same facts as Ed mentioned, it takes a lot more R&D to implement it so = that's why it's currently unused. Tracy Sent from my iPad On Aug 29, 2011, at 8:33 AM, "Ed Anderson" > wrote: The problem with Knock sensors is that they need to be able to identify th= e "knock" sound characteristic of the engine you have it on. The circuit i= s basically simple - the challenge is design the parameters of a signal fil= ter that permits the circuit to properly identify (filter) the "Knock" char= actertistic of your particular engine. So I would suggest that a knock system for a rotary might have different ch= aracteristics than for a piston engine. So what might work fine for a pist= on engine might not work so well on a rotary. But, on the other hand it mi= ght work fine. Ed From: stevei@carey.asn.au Sent: Monday, August 29, 2011 3:45 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: How to tune with ADI? Hi Dave If you are chasing a circuit for knock sensing try: http://siliconchip.com= .au/cms/A_108910/article.html Cheers Steve Izett Perth WA On 29/08/2011, at 12:24 PM, David Leonard wrote: Ok, So I have the new ADI system installed and working.... I think? Some of you smart racing guys probably have experience with ADI. Most of the instructions that come with tuning it are directed toward car g= uys that have computers and knock sensors. All they do is turn the system = on and the computer allows more advance because I is not sensing any knock.= The only real advise I have so for for me is that I should be running jus= t less than the amount of ADI that it takes to bog down the engine. My sys= tem is a fixed flow so I don't have much choice but it seems to be about ri= ght. If I use straight water (which I did for initial testing), the engine= bogs after about 10-15 seconds of ruining the ADI system. But when I uses= a 50/50 mix of water and denatured alcohol (too hard to find methanol arou= nd here, but close enough) the engine does not bog. So assuming my amount of ADI injected is about right, now I am supposed to = be able to lean to better power and advance the timing a little. But how m= uch? For the last testing flight I was using EGT for lack of a better guid= e. When the ADI comes on, my EGT drops by about 30 deg C, and there is a h= int of roughness to the engine. I can then lean a little and the roughness= clears up. For my test flight I leaned until my EFT came back up to where= I normally limit it (890 deg C). But if I then add 5 more inches of MAP, = there is still a hint of roughness even at 890 deg and I get the sense that= it wants to be leaned a little more. But I am afraid to do that... We are= talking 45" MAP and 7300 RPM here (185 KTS indicated (Vne) and climbing at= 500 fpm). So here are my questions: Is EGT a useful tool here, and does leaning to get the EGT back to 890 make= any sense? Since Methanol will do such a good job at preventing detonation, is it safe= to lean further toward best power (peak EGT)? (note, that will be hard on = the turbo... I need to remember to bring the spare one to Reno) How much advance do you think i can add? I was previously ruining 5 deg ah= ead of Tracy's recommended initial set up. Can't give a number because the= EC2 retards the timing with higher MAP's. How much, I have not heard. I = can easily add one deg at a time using Ed's EFI monitor. But without a kno= ck sensor am really in the blind. Thoughts? -- David Leonard Turbo Rotary RV-6 N4VY http://N4VY.RotaryRoster.net http://RotaryRoster.net ________________________________ The contents of this email are confidential and intended only for the named= recipients of this e-mail. If you have received this e-mail in error, you = are hereby notified that any use, reproduction, disclosure or distribution = or the information contained in this e-mail is prohibited. Please notify th= e sender immediately and then delete/destroy the e-mail and any printed cop= ies. All liability for viruses is excluded to the fullest extent of the law= . --_000_B27B6471A6AE418F9637E33760BFBF97careyasnau_ Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Hi Ed
I've had the eng= ine running 18months ago but have it off the fuse so I can rotate the thing= for sanding. 
I'm building a Glasair Super II RG. Just fini= shing the Slotted Flaps at present.
Hoping to put her together an= d retest engine by early next year.
Sorry, not much help for now.=

Cheers

Steve
<= br>
On 30/08/2011, at 7:50 PM, Ed Anderson wrote:

Hi Steve,
 
My understanding (Lynn will probably correct me h= ere) is=20 that under normal loads, temps and fuel the probability of detonation or kn= ock=20 in a rotary engine is pretty small due to the characteristics of its combus= tion=20 chamber.  Now under boost, there is no question you can get into the=20 detonation range, so it would seem to me that a knock sensor would be of bi= ggest=20 benefit to those with forced induction. 
 
I , for one, would be very interested in what you= find=20 when you listen in.  Wonder whether you might be able to make an audio= =20 recording of what the systems puts out - there are some interesting analyti= cal=20 tools as pointed out by Finn and several others that might be interesting t= o run=20 the data through.
 
I presume you have the engine running - just not = up to=20 full power, yet?
 
Ed

Sent: Tuesday, August 30, 2011 4:38 AM
Subject: [FlyRotary] Re: Freq analysis of Knock=20 sensor?

Hi Ed=20

My Renesis came with the knock sensor, but as you say the bandwidth of= the=20 sensor is probably to wide.
Having the sensor I built up a kit knock sensor amp and filters. But a= s we=20 recognise the knock of a rotor may sound vastly different from a piston.
I plan to listen in when I get to full power ground runs.
Problem being I don't want to punish my engine to hear what it sounds = like=20 when its complaining!

Cheers

Steve Izett
On 29/08/2011, at 10:36 PM, Ed Anderson wrote:

A thought occurred to me.  If anyone has a= spectrum=20 analyzer (Steve??) and could obtain an Rotary Knock sensor - that perhaps= =20 determining the frequency response of the knock sensor MIGHT indicate the= =20 frequency band pass required.  Although it is likely to be too broad= to=20 be much help if ( as likely) they do the filtering through a bandpass fil= ter=20 within the engine CPU.
 
Ed

From: Ed Anderson
Sent: Monday, August 29, 2011 9:54 AM
Subject: [FlyRotary] Not so Simple was Knock sensor was tune = with=20 ADI: [FlyRotary] Re: How to tune with ADI?

As Tracy also indicated - in may cases, &n= bsp;what=20 initially appears simple - frequently turns out not to be the case,= =20  when you dive into the details. 
 
Another seemingly simple project I thought abou= t, was to=20 add a wide band O2 (WBO2) sensor option for the EFISM.  This in= =20 order to provide more accurate info on the air/fuel ratio (although one c= ould=20 argue just how useful that might be for our applications).  <= /div>
 
While providing an algorithm for the different = voltage=20 input curve of the WBO2 sensor (it is much more linear than the narr= ow=20 band O2 sensor curve) is straightforward, when you dive deeper you discov= er=20 that:
 
1.  For the wide band O2 sensor to provide= accurate=20 information the sensor temperature must be held within a critical na= rrow=20  range.
2.  To do this properly, the WBO2 =20 manufacturer either programs into the automobile's  CPU or provides = a=20 separate "control" chip that uses a PID (Proportional, Integral, derivati= ve)=20 the control algorithm necessary to hold the required critical temperature= =20 range.
3.  Failure to hold this temp range render= s the=20 sensor output of questionable accuracy and will lead to degradation/failu= re of=20 the sensor.
4.  The PID temp control is much more comp= lex than=20 the algorithm required to read the output voltage
 
So while I could add the WBO2 sensor - without = the=20 separate algorithm (or control chip), the validity of the data is uncerta= in=20 and likely misleading.  So no WBO2 option any time soon.
 
Yet this project is much more straightforward t= han a=20 knock sensor.  Most automobile engine manufactures can afford to do = the=20 research and they can spread the cost over millions of engines sold. = ; As=20 you might imagine, the results of their R&D is considered proprietary= =20 information and seldom available to the public.
 
Ed
 
 

From: Tracy
Sent: Monday, August 29, 2011 9:24 AM
Subject: [FlyRotary] Re: How to tune with ADI?

What Ed said.   There is a knock sensor input on the EC3 but af= ter=20 finding the same facts as Ed mentioned, it takes a lot more R&D to=20 implement it so that's why it's currently unused.

Tracy

Sent from my iPad

On Aug 29, 2011, at 8:33 AM, "Ed Anderson" <eanderson@carolina.rr.com>=20 wrote:

The problem with Knock sensors is that they n= eed to be=20 able to identify  the "knock" sound characteristic of the engine y= ou=20 have it on.  The circuit is basically simple - the challenge is de= sign=20 the parameters of a signal filter that permits the circuit to properly= =20 identify (filter) the "Knock" charactertistic of your particu= lar=20 engine. 
 
So I would suggest that a knock system for a = rotary=20 might have different characteristics than for a piston engine.  So= what=20 might work fine for a piston engine might not work so well on a=20 rotary.  But, on the other hand it might work fine.
 
Ed

Sent: Monday, August 29, 2011 3:45 AM
Subject: [FlyRotary] Re: How to tune with ADI?
<= /div>

Hi Dave=20
If you are chasing a circuit for knock sensing try:

Cheers

Steve Izett
Perth WA
On 29/08/2011, at 12:24 PM, David Leonard wrote:

Ok,  So I have the new ADI system installed and=20 working....  I think?
 
Some of you smart racing guys probably have experience with=20 ADI.
 
Most of the instructions that come with tuning it are directed t= oward=20 car guys that have computers and knock sensors.  All they do is = turn=20 the system on and the computer allows more advance because I is not=20 sensing any knock.  The only real advise I have so for for me is= that=20 I should be running just less than the amount of ADI that it takes to= bog=20 down the engine.  My system is a fixed flow so I don't have much= =20 choice but it seems to be about right.  If I use straight water= =20 (which I did for initial testing), the engine bogs after about 10-15= =20 seconds of ruining the ADI system.  But when I uses a 50/50 mix = of=20 water and denatured alcohol (too hard to find methanol around here, b= ut=20 close enough) the engine does not bog.
 
So assuming my amount of ADI injected is about right, now I am=20 supposed to be able to lean to better power and advance the timing a= =20 little.  But how much?  For the last testing flight I was u= sing=20 EGT for lack of a better guide.  When the ADI comes on, my EGT d= rops=20 by about 30 deg C, and there is a hint of roughness to the engine.&nb= sp; I=20 can then lean a little and the roughness clears up.  For my test= =20 flight I leaned until my EFT came back up to where I normally limit i= t=20 (890 deg C).  But if I then add 5 more inches of MAP, there is s= till=20 a hint of roughness even at 890 deg and I get the sense that it wants= to=20 be leaned a little more. But I am afraid to do that...  We are=20 talking 45" MAP and 7300 RPM here (185 KTS indicated (Vne) and=20 climbing at 500 fpm). 
 
So here are my questions:
Is EGT a useful tool here, and does leaning to get the EGT back = to=20 890 make any sense?
Since Methanol will do such a good job at preventing detonation,= is=20 it safe to lean further toward best power (peak EGT)? (note, that wil= l be=20 hard on the turbo...  I need to remember to bring the spare= one=20 to Reno)
How much advance do you think i can add?  I was=20 previously ruining 5 deg ahead of Tracy's recommended initial se= t=20 up.  Can't give a number because the EC2 retards the timing= with=20 higher MAP's.  How much, I have not heard.  I can easily ad= d one=20 deg at a time using Ed's EFI monitor.  But without a knock senso= r am=20 really in the blind.
 
Thoughts? 

--
David Leonard
Turbo=20 Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net
= http://RotaryRoster.net


The contents of this ema= il are=20 confidential and intended only for the named recipients of this e-mail.= If=20 you have received this e-mail in error, you are hereby notified that an= y=20 use, reproduction, disclosure or distribution or the information contai= ned=20 in this e-mail is prohibited. Please notify the sender immediately and = then=20 delete/destroy the e-mail and any printed copies. All liability for vir= uses=20 is excluded to the fullest extent of the=20 law.


= --_000_B27B6471A6AE418F9637E33760BFBF97careyasnau_--