X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail-fx0-f52.google.com ([209.85.161.52] verified) by logan.com (CommuniGate Pro SMTP 5.4.1) with ESMTPS id 5107436 for flyrotary@lancaironline.net; Mon, 29 Aug 2011 14:52:15 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.161.52; envelope-from=wdleonard@gmail.com Received: by fxd18 with SMTP id 18so4466102fxd.25 for ; Mon, 29 Aug 2011 11:51:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=CgNau4L/lx7ac4AohDN96qAzj86Fibaks2nlybFIkb8=; b=U03uHm4swCHjLL+dDH8fjUNFuJwsh6qvno81akiI5bZlxWVC3+U5UEryl6zdw8YWi7 pK4IzVP7F0tQkKtTPZXgimerqhi20UAkkh/v7wuoUE7f53hSmrjJAnUlz69gsBh9c1RQ FBIN/KuhK6QrKR8SNy919G8NrkVKxBcaAOpvk= MIME-Version: 1.0 Received: by 10.223.62.73 with SMTP id w9mr725097fah.138.1314643897045; Mon, 29 Aug 2011 11:51:37 -0700 (PDT) Received: by 10.223.74.202 with HTTP; Mon, 29 Aug 2011 11:51:36 -0700 (PDT) In-Reply-To: References: Date: Mon, 29 Aug 2011 11:51:36 -0700 Message-ID: Subject: Re: [FlyRotary] Freq analysis of Knock sensor? From: David Leonard To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=00151748de467d52e204aba96213 --00151748de467d52e204aba96213 Content-Type: text/plain; charset=ISO-8859-1 By Rotary Knock sensor, I am not sure if you mean the computer itself, or the sensor. I think that the sensors are all pretty much the same, just a form of microphone. It is not the sensor that is tuned to the engine, but the filters in the computer. And if you had a computer, you wouldn't need to build another one unless you wanted to sell them. -- David Leonard Turbo Rotary RV-6 N4VY http://N4VY.RotaryRoster.net http://RotaryRoster.net On Mon, Aug 29, 2011 at 7:36 AM, 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 frequency > response of the knock sensor MIGHT indicate the frequency band pass > required. 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: > [FlyRotary] Re: How to tune with ADI? > > As Tracy also indicated - in may cases, what initially appears simple > - frequently 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 accurate > 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 > WBO2 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 > automobile's CPU or provides a separate "control" chip that uses a PID > (Proportional, 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 > questionable accuracy and will lead to degradation/failure of the sensor. > 4. The PID temp control is much more complex than the algorithm required > to read the output voltage > > So while I could add the WBO2 sensor - without the separate algorithm (or > control 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 > automobile engine manufactures can afford to do the research and they can > spread the cost over millions of engines sold. As you might imagine, the > results 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 > the "knock" sound characteristic of the engine you have it on. The circuit > is basically simple - the challenge is design the parameters of a signal > filter that permits the circuit to properly identify (filter) the "Knock" > charactertistic of your particular engine. > > So I would suggest that a knock system for a rotary might have different > characteristics than for a piston engine. So what might work fine for a > piston engine might not work so well on a rotary. But, on the other hand it > might 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 > guys 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 just > less than the amount of ADI that it takes to bog down the engine. My system > is a fixed flow so I don't have much choice but it seems to be about right. > 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 around > 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 > much? For the last testing flight I was using EGT for lack of a better > guide. When the ADI comes on, my EGT drops by about 30 deg C, and there is > a hint 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 > ahead 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 > knock 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 the > sender immediately and then delete/destroy the e-mail and any printed > copies. All liability for viruses is excluded to the fullest extent of the > law. > > --00151748de467d52e204aba96213 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable By Rotary Knock sensor, I am not sure if you mean the computer itself, or t= he sensor.=A0 I think that the sensors are all pretty much the same, just a= form of microphone.=A0 It is not the sensor that is tuned to the engine, b= ut the filters in the computer.=A0 And if you had a computer, you wouldn= 9;t need to build another one unless you wanted to sell them.

--
David Leonard

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

On Mon, Aug 29, 2011 at 7:36 AM, Ed Anderson <eanderson@carolina.rr.com> wrote:
A thought occurred to me.=A0 If anyone has a spec= trum=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.=A0 Although it is likely to be too broad to b= e=20 much help if ( as likely) they do the filtering through a bandpass filter w= ithin=20 the engine CPU.
=A0
Ed

Sent: Monday, August 29, 2011 9:54 AM
To: Rotary motors in aircraft <= /div>
Subject: [FlyRotary] Not so Simple was Knock sensor was tune wi= th=20 ADI: [FlyRotary] Re: How to tune with ADI?

As Tracy also indicated=A0- in may cases, =A0what= =20 initially appears simple -=A0frequently turns out not to be the case,=20 =A0when you dive into the details.=A0
=A0
Another seemingly simple project I thought about,= was to=20 add a wide band O2 (WBO2) sensor option for the EFISM.=A0 This=A0in order= =20 to provide more accurate info on the air/fuel ratio (although one could arg= ue=20 just how useful that might be for our applications).=A0
=A0
While providing an algorithm for the different vo= ltage=20 input curve of the WBO2 sensor=A0(it is much more linear than the narrow ba= nd=20 O2 sensor curve) is straightforward, when you dive deeper you discover=20 that:
=A0
1.=A0 For the wide band O2 sensor to provide accu= rate=20 information the sensor temperature must be held within a critical=A0narrow= =20 =A0range.
2.=A0 To do this properly, the WBO2=A0 manufactur= er=20 either programs into the automobile's =A0CPU or provides a separate &qu= ot;control"=20 chip that uses a PID (Proportional, Integral, derivative) the control algor= ithm=20 necessary to hold the required critical temperature range.
3.=A0 Failure to hold this temp range renders the= =20 sensor output of questionable accuracy and will lead to degradation/failure= of=20 the sensor.
4.=A0 The PID temp control is much more complex t= han=20 the algorithm required to read the output voltage
=A0
So while I could add the WBO2 sensor - without th= e=20 separate algorithm (or control chip), the validity of the data is uncertain= and=20 likely misleading.=A0 So no WBO2 option any time soon.
=A0
Yet this project is much more straightforward tha= n a knock=20 sensor.=A0 Most automobile engine manufactures can afford to do the researc= h=20 and they can spread the cost over millions of engines sold.=A0 As you might= =20 imagine, the results of their R&D is considered proprietary information= and=20 seldom available to the public.
=A0
Ed
=A0
=A0

From: Tracy
Sent: Monday, August 29, 2011 9:24 AM
To: Rotary motors in aircraft <= /div>
Subject: [FlyRotary] Re: How to tune with ADI?

What Ed said. =A0 There is a knock sensor input on the EC3 but after= =20 finding the same facts as Ed mentioned, it takes a lot more R&D to impl= ement=20 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 nee= d to be=20 able to identify=A0 the "knock" sound characteristic of the eng= ine you have=20 it on.=A0 The circuit is basically simple - the challenge is design the= =20 parameters of a signal filter that permits the circuit to properly identi= fy=20 (filter)=A0the "Knock" charactertistic of=A0your particular=20 engine.=A0
=A0
So I would suggest that a knock system for a ro= tary=20 might have different characteristics than for a piston engine.=A0 So what= =20 might work fine for a piston engine might not work so well on a rotary.= =A0=20 But, on the other hand it might work fine.
=A0
Ed

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

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,=A0 So I have the new ADI system installed and working....=A0= =20 I think?
=A0
Some of you smart racing guys probably have experience with ADI.
=A0
Most of the instructions that come with tuning it are directed tow= ard=20 car guys that have computers and knock sensors.=A0 All they do is turn= =20 the system on and the computer allows more advance because I is not sen= sing=20 any knock.=A0 The only real advise I have so for for me is that I shoul= d=20 be running just less than the amount of ADI that it takes to bog down t= he=20 engine.=A0 My system is a fixed flow so I don't have much choice bu= t it=20 seems to be about right.=A0 If I use straight water (which I did for=20 initial testing), the engine bogs after about 10-15 seconds of ruining = the=20 ADI system.=A0 But when I uses a 50/50 mix of water and denatured alcoh= ol=20 (too hard to find methanol around here, but close enough) the engine do= es=20 not bog.
=A0
So assuming my amount of ADI injected is about right, now I am sup= posed=20 to be able to lean to better power and advance the timing a little.=A0= =20 But how much?=A0 For the last testing flight I was using EGT for lack o= f=20 a better guide.=A0 When the ADI comes on, my EGT drops by about 30 deg = C,=20 and there is a hint of roughness to the engine.=A0 I can then lean a=20 little and the roughness clears up.=A0 For my test flight I leaned unti= l=20 my EFT came back up to where I normally limit it (890 deg C).=A0 But if= I=20 then add 5 more inches of MAP, there is still a hint of roughness even = at=20 890 deg and I get the sense that it wants to be leaned a little more. B= ut I=20 am afraid to do that...=A0 We are talking 45" MAP and 7300 RPM her= e (185=20 KTS indicated (Vne)=A0and climbing at 500 fpm).=A0
=A0
So here are my questions:
Is EGT a useful tool here, and does leaning to get the EGT back to= 890=20 make any sense?
Since Methanol will do such a good job at preventing detonation, i= s it=20 safe to lean further toward best power (peak EGT)? (note, that will be = hard=20 on the turbo...=A0 I need to remember to=A0bring the spare one to=20 Reno)
How much advance do you think i can add?=A0 I=A0was=20 previously=A0ruining 5 deg ahead of Tracy's recommended initial set= =20 up.=A0 Can't give a number=A0because the EC2 retards the timing wit= h=20 higher MAP's.=A0 How much, I have not heard.=A0 I can easily add on= e=20 deg at a time using Ed's EFI monitor.=A0 But without a knock sensor= am=20 really in the blind.
=A0
Thoughts?=A0

--
David Leonard

Tur= bo=20 Rotary RV-6 N4VY
htt= p://N4VY.RotaryRoster.net
http= ://RotaryRoster.net


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



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