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Lycoming Knock Sensor

 
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PostPosted: Sun Sep 30, 2018 8:10 pm    Post subject: Lycoming Knock Sensor Reply with quote

Hi All,

Has anyone installed a knock sensor in their Lycoming?

If so what make and model of knock sensor did you install and where did you install the sensor?

Also whatever other information/tips/tricks/recommendations would be most appreciated!!!

Thanks,
Bill Hunter


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PostPosted: Sun Sep 30, 2018 8:52 pm    Post subject: Lycoming Knock Sensor Reply with quote

I have never heard of a knock sensor on a Lycoming, even one with electronic mags. I don't see why you couldn't install one in any of the 1/8 NPT primer ports though.

On Sun, Sep 30, 2018 at 9:14 PM <billhuntersemail(at)gmail.com (billhuntersemail(at)gmail.com)> wrote:

Quote:
--> AeroElectric-List message posted by: <billhuntersemail(at)gmail.com (billhuntersemail(at)gmail.com)>

Hi All,

Has anyone installed a knock sensor in their Lycoming?

If so what make and model of knock sensor did you install and where did you install the sensor?

Also whatever other information/tips/tricks/recommendations would be most appreciated!!!



Thanks,
Bill Hunter



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PostPosted: Mon Oct 01, 2018 9:16 am    Post subject: Lycoming Knock Sensor Reply with quote

Problem is likely to be knowing what to listen for, since an air cooled engine with individual cylinders is going to 'sound' quite different from a water cooled integrated block engine. A Lyc is so sloppy loose compared to an auto engine that it might trigger the sensor constantly. Smile

On 9/30/2018 11:51 PM, Sebastien wrote:

Quote:
I have never heard of a knock sensor on a Lycoming, even one with electronic mags. I don't see why you couldn't install one in any of the 1/8 NPT primer ports though.

On Sun, Sep 30, 2018 at 9:14 PM <billhuntersemail(at)gmail.com (billhuntersemail(at)gmail.com)> wrote:

Quote:
--> AeroElectric-List message posted by: <billhuntersemail(at)gmail.com (billhuntersemail(at)gmail.com)>

Hi All,

Has anyone installed a knock sensor in their Lycoming?

If so what make and model of knock sensor did you install and where did you install the sensor?

Also whatever other information/tips/tricks/recommendations would be most appreciated!!!



Thanks,
Bill Hunter


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nuckolls.bob(at)aeroelect
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PostPosted: Mon Oct 01, 2018 9:23 am    Post subject: Lycoming Knock Sensor Reply with quote

At 11:51 PM 9/30/2018, you wrote:
Quote:
I have never heard of a knock sensor on a Lycoming, even one with electronic mags. I don't see why you couldn't install one in any of the 1/8 NPT primer ports though.

Knock sensors are specialized microphones
mounted to some sturdy feature of the
crankcase. The device is optimized to
detect 'knock tones' in the 4-6 Khz range
(determined by cylinder bore diameter).

There are no plug-n-play sensors . . . i.e.
devices that will light a bulb when knocking
is detected. They all require some degree
of signal conditioning to separate noises
of interest from the rest. Here's on example
of a product paired with a sensor that
will illuminate an annunciator when knocking
is detected.

https://tinyurl.com/y79tde7s

There is a constellation of Arduino based
sensor detection projects including sample
software

https://tinyurl.com/hsq4mee

This brings to mind another knowledge nugget
I was offered at a Burlington CO fly-in about
15 years ago. The legacy oxygen sensors used
on automobiles have been demonstrated to function
as advertised in 100LL engines. Met a fellow
with an O2 sensor paired with a millivoltmeter
on the panel. He asserted that the sensor had
several hundred hours on it and had not succumbed
to the predicted 'lead fouling' that discouraged
use on aircraft engines.

One might consider an automotive O2 sensor as
an adjunct for achieving consistent mixture
settings. Here's a short article on how they
work:

https://tinyurl.com/ybm74fvh





Bob . . .


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bob.verwey(at)gmail.com
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PostPosted: Mon Oct 01, 2018 9:37 am    Post subject: Lycoming Knock Sensor Reply with quote

Thanks for posting Bob....very interesting!

On Mon, 01 Oct 2018, 7:28 PM Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:

Quote:
At 11:51 PM 9/30/2018, you wrote:
Quote:
I have never heard of a knock sensor on a Lycoming, even one with electronic mags. I don't see why you couldn't install one in any of the 1/8 NPT primer ports though.

  Knock sensors are specialized microphones
  mounted to some sturdy feature of the
  crankcase. The device is optimized to
  detect 'knock tones' in the 4-6 Khz range
  (determined by cylinder bore diameter).

  There are no plug-n-play sensors . . . i.e.
  devices that will light a bulb when knocking
  is detected. They all require some degree
  of signal conditioning to separate noises
  of interest from the rest. Here's on example
  of a product paired with a sensor that
  will illuminate an annunciator when knocking
  is detected.

https://tinyurl.com/y79tde7s

  There is a constellation of Arduino based
  sensor detection projects including sample
  software

https://tinyurl.com/hsq4mee

  This brings to mind another knowledge nugget
  I was offered at a Burlington CO fly-in about
  15 years ago. The legacy oxygen sensors used
  on automobiles have been demonstrated to function
  as advertised in 100LL engines. Met a fellow
  with an O2 sensor paired with a millivoltmeter
  on the panel.  He asserted that the sensor had
  several hundred hours on it and had not succumbed
  to the predicted 'lead fouling' that discouraged
  use on aircraft engines.

  One might consider an automotive O2 sensor as
  an adjunct for achieving consistent mixture
  settings. Here's a short article on how they
  work:

https://tinyurl.com/ybm74fvh

 



  Bob . . .


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BARRY CHECK 6



Joined: 15 Mar 2011
Posts: 720

PostPosted: Mon Oct 01, 2018 10:22 am    Post subject: Lycoming Knock Sensor Reply with quote

Good post Bob,

And then even if one installs a knock sensor, what are you going to do with that information?
Sending it to a DMM only gets you a number what does that number mean?
Does the pilot have a known acceptable value?
How much of a change is acceptable?
How is one going to take that voltage / current and change the timing of the engine?
I guess all the above becomes moot if one installs an car engine and computer.
Barry

On Monday, October 1, 2018, Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:
Quote:
At 11:51 PM 9/30/2018, you wrote:
Quote:
I have never heard of a knock sensor on a Lycoming, even one with electronic mags. I don't see why you couldn't install one in any of the 1/8 NPT primer ports though.

  Knock sensors are specialized microphones
  mounted to some sturdy feature of the
  crankcase. The device is optimized to
  detect 'knock tones' in the 4-6 Khz range
  (determined by cylinder bore diameter).

  There are no plug-n-play sensors . . . i.e.
  devices that will light a bulb when knocking
  is detected. They all require some degree
  of signal conditioning to separate noises
  of interest from the rest. Here's on example
  of a product paired with a sensor that
  will illuminate an annunciator when knocking
  is detected.

https://tinyurl.com/y79tde7s

  There is a constellation of Arduino based
  sensor detection projects including sample
  software

https://tinyurl.com/hsq4mee

  This brings to mind another knowledge nugget
  I was offered at a Burlington CO fly-in about
  15 years ago. The legacy oxygen sensors used
  on automobiles have been demonstrated to function
  as advertised in 100LL engines. Met a fellow
  with an O2 sensor paired with a millivoltmeter
  on the panel.  He asserted that the sensor had
  several hundred hours on it and had not succumbed
  to the predicted 'lead fouling' that discouraged
  use on aircraft engines.

  One might consider an automotive O2 sensor as
  an adjunct for achieving consistent mixture
  settings. Here's a short article on how they
  work:

https://tinyurl.com/ybm74fvh

 



  Bob . . .

--
Barry
"Chop'd Liver"
If you wash your hands before you go to the bathroom you may have the makings of a Crew Chief.


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PostPosted: Mon Oct 01, 2018 10:39 am    Post subject: Lycoming Knock Sensor Reply with quote

O2 sensors (mostly wideband, now) are already very common among alternative (auto) engine users. The primary aftermarket auto-style controller vendor for Lycs (SDS) strongly encourages their use, as well. The wideband sensors, especially the later generation ones, seem to be fairly resistant (though not immune) to lead fouling.
Charlie
Charlie
On Oct 1, 2018, at 12:28 PM, "Robert L. Nuckolls, III" <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:
Quote:
At 11:51 PM 9/30/2018, you wrote:
Quote:
I have never heard of a knock sensor on a Lycoming, even one with electronic mags. I don't see why you couldn't install one in any of the 1/8 NPT primer ports though.

Knock sensors are specialized microphones
mounted to some sturdy feature of the
crankcase. The device is optimized to
detect 'knock tones' in the 4-6 Khz range
(determined by cylinder bore diameter).

There are no plug-n-play sensors . . . i.e.
devices that will light a bulb when knocking
is detected. They all require some degree
of signal conditioning to separate noises
of interest from the rest. Here's on example
of a product paired with a sensor that
will illuminate an annunciator when knocking
is detected.

https://tinyurl.com/y79tde7s

There is a constellation of Arduino based
sensor detection projects including sample
software

https://tinyurl.com/hsq4mee

This brings to mind another knowledge nugget
I was offered at a Burlington CO fly-in about
15 years ago. The legacy oxygen sensors used
on automobiles have been demonstrated to function
as advertised in 100LL engines. Met a fellow
with an O2 sensor paired with a millivoltmeter
on the panel. He asserted that the sensor had
several hundred hours on it and had not succumbed
to the predicted 'lead fouling' that discouraged
use on aircraft engines.

One might consider an automotive O2 sensor as
an adjunct for achieving consistent mixture
settings. Here's a short article on how they
work:

https://tinyurl.com/ybm74fvh





Bob . . .


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nuckolls.bob(at)aeroelect
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PostPosted: Mon Oct 01, 2018 11:15 am    Post subject: Lycoming Knock Sensor Reply with quote

At 01:22 PM 10/1/2018, you wrote:
Quote:
Good post Bob,


And then even if one installs a knock sensor, what are you going to do with that information?
Sending it to a DMM only gets you a number what does that number mean?

Knock sensors are not analog . . . if there is any
presence of a pre-ignition noise signature, you
get a light suggesting that a change of engine
configuration is indicated.

The O2 sensor is analog. With some experimentation,
one can deduce an O2 reading that is consistent
with the targeted mixture setting. EGT, another
analog signal, has been used to this purpose
since day-one . . . O2 sensing is just another
approach.



Bob . . .


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billhuntersemail(at)gmail
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PostPosted: Tue Oct 02, 2018 8:02 am    Post subject: Lycoming Knock Sensor Reply with quote

Gentlemen,



Thank you for your reply and sorry for the delay in my reply as I was flying
all day yesterday.



Firstly...THANK YOU for your assistance on this...GREATLY APPRECIATED!!!



I have a Lycoming TIO-540 and I run LOP with balanced injectors.



I understand the concept of one sensor per cylinder and I also understand
that the cylinders on the air-cooled aircraft engine is not as tightly
connected to the engine block as a water cooled engine however sound travels
through metal quite quickly and I would think that the sound would move from
each cylinder head to the block.



Would not one sensor mounted on the crankcase "hear" the pings?



I can see if I only installed one sensor on the head of cylinder #1 and a
pinging in cylinder #6 would have a long way to travel and the sound would
distort so the sensor would be unreliable for any cylinder other than its
installed #1 position.



The Knocksense unit that Bob posted is precisely the one that I was looking
at. I was thinking of buying two units and install them at the top of the
engine with one closer to the front and the second closer to the back. On
the Lyco-Saurus the bottom of the engine has the intake and oil pan so I
imagine the liquid and distance from the source of the sound would dampen
out the sound. When you order them they ask you for your cylinder diameter
so they can tune the sensor to your engine.



The next question is.how do you test to see if the darn thing is working?


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csmale(at)bak.rr.com
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PostPosted: Tue Oct 02, 2018 8:40 am    Post subject: Lycoming Knock Sensor Reply with quote

Look up efi101.com. This web site has multiple posts on knock or detonation. Will have to do a search to find posts on knock. A very good site. csmale(at)bak.rr.com (csmale(at)bak.rr.com)

On 10/02/2018 09:01 AM, billhuntersemail(at)gmail.com (billhuntersemail(at)gmail.com) wrote:

Quote:
<![endif]--> <![endif]-->
Gentlemen,

Thank you for your reply and sorry for the delay in my reply as I was flying all day yesterday.

Firstly...THANK YOU for your assistance on this...GREATLY APPRECIATED!!!

I have a Lycoming TIO-540 and I run LOP with balanced injectors.

I understand the concept of one sensor per cylinder and I also understand that the cylinders on the air-cooled aircraft engine is not as tightly connected to the engine block as a water cooled engine however sound travels through metal quite quickly and I would think that the sound would move from each cylinder head to the block.

Would not one sensor mounted on the crankcase hear the pings?

I can see if I only installed one sensor on the head of cylinder #1 and a pinging in cylinder #6 would have a long way to travel and the sound would distort so the sensor would be unreliable for any cylinder other than its installed #1 position.

The Knocksense unit that Bob posted is precisely the one that I was looking at. I was thinking of buying two units and install them at the top of the engine with one closer to the front and the second closer to the back. On the Lyco-Saurus the bottom of the engine has the intake and oil pan so I imagine the liquid and distance from the source of the sound would dampen out the sound. When you order them they ask you for your cylinder diameter so they can tune the sensor to your engine.

The next question ishow do you test to see if the darn thing is working?

Thanks,
Bill Hunter


From: owner-aeroelectric-list-server(at)matronics.com (owner-aeroelectric-list-server(at)matronics.com) <owner-aeroelectric-list-server(at)matronics.com> (owner-aeroelectric-list-server(at)matronics.com) On Behalf Of Robert L. Nuckolls, III
Sent: Monday, October 1, 2018 10:23 AM
To: aeroelectric-list(at)matronics.com (aeroelectric-list(at)matronics.com)
Subject: Re: Lycoming Knock Sensor



At 11:51 PM 9/30/2018, you wrote:

Quote:

I have never heard of a knock sensor on a Lycoming, even one with electronic mags. I don't see why you couldn't install one in any of the 1/8 NPT primer ports though.


Knock sensors are specialized microphones
mounted to some sturdy feature of the
crankcase. The device is optimized to
detect 'knock tones' in the 4-6 Khz range
(determined by cylinder bore diameter).

There are no plug-n-play sensors . . . i.e.
devices that will light a bulb when knocking
is detected. They all require some degree
of signal conditioning to separate noises
of interest from the rest. Here's on example
of a product paired with a sensor that
will illuminate an annunciator when knocking
is detected.

https://tinyurl.com/y79tde7s

There is a constellation of Arduino based
sensor detection projects including sample
software

https://tinyurl.com/hsq4mee

This brings to mind another knowledge nugget
I was offered at a Burlington CO fly-in about
15 years ago. The legacy oxygen sensors used
on automobiles have been demonstrated to function
as advertised in 100LL engines. Met a fellow
with an O2 sensor paired with a millivoltmeter
on the panel. He asserted that the sensor had
several hundred hours on it and had not succumbed
to the predicted 'lead fouling' that discouraged
use on aircraft engines.

One might consider an automotive O2 sensor as
an adjunct for achieving consistent mixture
settings. Here's a short article on how they
work:

https://tinyurl.com/ybm74fvh






Bob . . .


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skywagon185(at)gmail.com
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PostPosted: Tue Oct 02, 2018 9:47 am    Post subject: Lycoming Knock Sensor Reply with quote

. . .wouldn't you want to mount the sensors such that their sense axis is in the same plane as the knock vibration; namely line up with the piston rods and not on top pf the engine case...?
On Tue, Oct 2, 2018 at 9:09 AM <billhuntersemail(at)gmail.com (billhuntersemail(at)gmail.com)> wrote:

Quote:

Gentlemen,
 
Thank you for your reply and sorry for the delay in my reply as I was flying all day yesterday.
 
Firstly...THANK YOU for your assistance on this...GREATLY APPRECIATED!!!
 
I have a Lycoming TIO-540 and I run LOP with balanced injectors. 
 
I understand the concept of one sensor per cylinder and I also understand that the cylinders on the air-cooled aircraft engine is not as tightly connected to the engine block as a water cooled engine however sound travels through metal quite quickly and I would think that the sound would move from each cylinder head to the block. 
 
Would not one sensor mounted on the crankcase “hear” the pings? 
 
I can see if I only installed one sensor on the head of cylinder #1 and a pinging in cylinder #6 would have a long way to travel and the sound would distort so the sensor would be unreliable for any cylinder other than its installed #1 position.
 
The Knocksense unit that Bob posted is precisely the one that I was looking at.  I was thinking of buying two units and install them at the top of the engine with one closer to the front and the second closer to the back.  On the Lyco-Saurus the bottom of the engine has the intake and oil pan so I imagine the liquid and distance from the source of the sound would dampen out the sound.  When you order them they ask you for your cylinder diameter so they can tune the sensor to your engine.
 
The next question is…how do you test to see if the darn thing is working? 

Thanks,
Bill Hunter

 
From: owner-aeroelectric-list-server(at)matronics.com (owner-aeroelectric-list-server(at)matronics.com) <owner-aeroelectric-list-server(at)matronics.com (owner-aeroelectric-list-server(at)matronics.com)> On Behalf Of Robert L. Nuckolls, III
Sent: Monday, October 1, 2018 10:23 AM
To: aeroelectric-list(at)matronics.com (aeroelectric-list(at)matronics.com)
Subject: Re: Lycoming Knock Sensor
 
At 11:51 PM 9/30/2018, you wrote:

Quote:

I have never heard of a knock sensor on a Lycoming, even one with electronic mags. I don't see why you couldn't install one in any of the 1/8 NPT primer ports though.


  Knock sensors are specialized microphones
  mounted to some sturdy feature of the
  crankcase. The device is optimized to
  detect 'knock tones' in the 4-6 Khz range
  (determined by cylinder bore diameter).

  There are no plug-n-play sensors . . . i.e.
  devices that will light a bulb when knocking
  is detected. They all require some degree
  of signal conditioning to separate noises
  of interest from the rest. Here's on example
  of a product paired with a sensor that
  will illuminate an annunciator when knocking
  is detected.

https://tinyurl.com/y79tde7s

  There is a constellation of Arduino based
  sensor detection projects including sample
  software

https://tinyurl.com/hsq4mee

  This brings to mind another knowledge nugget
  I was offered at a Burlington CO fly-in about
  15 years ago. The legacy oxygen sensors used
  on automobiles have been demonstrated to function
  as advertised in 100LL engines. Met a fellow
  with an O2 sensor paired with a millivoltmeter
  on the panel.  He asserted that the sensor had
  several hundred hours on it and had not succumbed
  to the predicted 'lead fouling' that discouraged
  use on aircraft engines.

  One might consider an automotive O2 sensor as
  an adjunct for achieving consistent mixture
  settings. Here's a short article on how they
  work:

https://tinyurl.com/ybm74fvh

 


  Bob . . .



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PostPosted: Tue Oct 02, 2018 11:43 am    Post subject: Lycoming Knock Sensor Reply with quote

Quote:
. . .wouldn't you want to mount the sensors such that their sense axis is in the same plane as the knock vibration; namely line up with the piston rods and not on top pf the engine case...?

I was kinda wondering the same thing.

If I had the money I would buy six knock detection systems and have one sensor per cylinder…and if I did the questions would be:
-Should one knock sensor be installed on the sidewall of each cylinder?

-Or should one knock sensor be installed at the top of the cylinder head near the rocker cover?

I am realistically only going to install one or two knock sensors so does the ping sound get transmitted through the metal of the engine to be heard practically everywhere?  If so then I imagine only one sensor installed on the crankcase split somewhere in the middle would be sufficient.  Yes if you only have one sensor then you really do not know what cylinder is pinging however for my purposes I simply want to halt detonation ASAP and I do not really know care what cylinder.

Thanks,
Bill Hunter

From: owner-aeroelectric-list-server(at)matronics.com <owner-aeroelectric-list-server(at)matronics.com> On Behalf Of skywagon185guy
Sent: Tuesday, October 2, 2018 10:47 AM
To: aeroelectric list <aeroelectric-list(at)matronics.com>
Subject: Re: Lycoming Knock Sensor

. . .wouldn't you want to mount the sensors such that their sense axis is in the same plane as the knock vibration; namely line up with the piston rods and not on top pf the engine case...?


On Tue, Oct 2, 2018 at 9:09 AM <billhuntersemail(at)gmail.com (billhuntersemail(at)gmail.com)> wrote:
Quote:

Gentlemen,

Thank you for your reply and sorry for the delay in my reply as I was flying all day yesterday.

Firstly...THANK YOU for your assistance on this...GREATLY APPRECIATED!!!

I have a Lycoming TIO-540 and I run LOP with balanced injectors.

I understand the concept of one sensor per cylinder and I also understand that the cylinders on the air-cooled aircraft engine is not as tightly connected to the engine block as a water cooled engine however sound travels through metal quite quickly and I would think that the sound would move from each cylinder head to the block.

Would not one sensor mounted on the crankcase “hear” the pings?

I can see if I only installed one sensor on the head of cylinder #1 and a pinging in cylinder #6 would have a long way to travel and the sound would distort so the sensor would be unreliable for any cylinder other than its installed #1 position.

The Knocksense unit that Bob posted is precisely the one that I was looking at. I was thinking of buying two units and install them at the top of the engine with one closer to the front and the second closer to the back. On the Lyco-Saurus the bottom of the engine has the intake and oil pan so I imagine the liquid and distance from the source of the sound would dampen out the sound. When you order them they ask you for your cylinder diameter so they can tune the sensor to your engine.

The next question is…how do you test to see if the darn thing is working?

Thanks,
Bill Hunter


From: owner-aeroelectric-list-server(at)matronics.com (owner-aeroelectric-list-server(at)matronics.com) <owner-aeroelectric-list-server(at)matronics.com (owner-aeroelectric-list-server(at)matronics.com)> On Behalf Of Robert L. Nuckolls, III
Sent: Monday, October 1, 2018 10:23 AM
To: aeroelectric-list(at)matronics.com (aeroelectric-list(at)matronics.com)
Subject: Re: Lycoming Knock Sensor

At 11:51 PM 9/30/2018, you wrote:
Quote:

I have never heard of a knock sensor on a Lycoming, even one with electronic mags. I don't see why you couldn't install one in any of the 1/8 NPT primer ports though.


Knock sensors are specialized microphones
mounted to some sturdy feature of the
crankcase. The device is optimized to
detect 'knock tones' in the 4-6 Khz range
(determined by cylinder bore diameter).

There are no plug-n-play sensors . . . i.e.
devices that will light a bulb when knocking
is detected. They all require some degree
of signal conditioning to separate noises
of interest from the rest. Here's on example
of a product paired with a sensor that
will illuminate an annunciator when knocking
is detected.

https://tinyurl.com/y79tde7s

There is a constellation of Arduino based
sensor detection projects including sample
software

https://tinyurl.com/hsq4mee

This brings to mind another knowledge nugget
I was offered at a Burlington CO fly-in about
15 years ago. The legacy oxygen sensors used
on automobiles have been demonstrated to function
as advertised in 100LL engines. Met a fellow
with an O2 sensor paired with a millivoltmeter
on the panel. He asserted that the sensor had
several hundred hours on it and had not succumbed
to the predicted 'lead fouling' that discouraged
use on aircraft engines.

One might consider an automotive O2 sensor as
an adjunct for achieving consistent mixture
settings. Here's a short article on how they
work:

https://tinyurl.com/ybm74fvh



Bob . . .



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csmale(at)bak.rr.com
Guest





PostPosted: Tue Oct 02, 2018 2:39 pm    Post subject: Lycoming Knock Sensor Reply with quote

knock sensing is quite complex.  Search efi101.com forums for posts on knock sensing. It will give you and idea of how to go about doing your proposal.  csmale(at)bak.rr.com (csmale(at)bak.rr.com)

On 10/02/2018 12:42 PM, billhuntersemail(at)gmail.com (billhuntersemail(at)gmail.com) wrote:

Quote:
<![endif]--> <![endif]-->
Quote:
. . .wouldn't you want to mount the sensors such that their sense axis is in the same plane as the knock vibration; namely line up with the piston rods and not on top pf the engine case...?
 

I was kinda wondering the same thing.
 
If I had the money I would buy six knock detection systems and have one sensor per cylinder…and if I did the questions would be:
-Should one knock sensor be installed on the sidewall of each cylinder?
 
-Or should one knock sensor be installed at the top of the cylinder head near the rocker cover?
 
I am realistically only going to install one or two knock sensors so does the ping sound get transmitted through the metal of the engine to be heard practically everywhere?  If so then I imagine only one sensor installed on the crankcase split somewhere in the middle would be sufficient.  Yes if you only have one sensor then you really do not know what cylinder is pinging however for my purposes I simply want to halt detonation ASAP and I do not really know care what cylinder.

Thanks,
Bill Hunter
 
From: owner-aeroelectric-list-server(at)matronics.com (owner-aeroelectric-list-server(at)matronics.com) <owner-aeroelectric-list-server(at)matronics.com> (owner-aeroelectric-list-server(at)matronics.com) On Behalf Of skywagon185guy
Sent: Tuesday, October 2, 2018 10:47 AM
To: aeroelectric list <aeroelectric-list(at)matronics.com> (aeroelectric-list(at)matronics.com)
Subject: Re: Lycoming Knock Sensor
 
. . .wouldn't you want to mount the sensors such that their sense axis is in the same plane as the knock vibration; namely line up with the piston rods and not on top pf the engine case...?

 
On Tue, Oct 2, 2018 at 9:09 AM <billhuntersemail(at)gmail.com (billhuntersemail(at)gmail.com)> wrote:
Quote:

Gentlemen,
 
Thank you for your reply and sorry for the delay in my reply as I was flying all day yesterday.
 
Firstly...THANK YOU for your assistance on this...GREATLY APPRECIATED!!!
 
I have a Lycoming TIO-540 and I run LOP with balanced injectors. 
 
I understand the concept of one sensor per cylinder and I also understand that the cylinders on the air-cooled aircraft engine is not as tightly connected to the engine block as a water cooled engine however sound travels through metal quite quickly and I would think that the sound would move from each cylinder head to the block. 
 
Would not one sensor mounted on the crankcase “hear” the pings? 
 
I can see if I only installed one sensor on the head of cylinder #1 and a pinging in cylinder #6 would have a long way to travel and the sound would distort so the sensor would be unreliable for any cylinder other than its installed #1 position.
 
The Knocksense unit that Bob posted is precisely the one that I was looking at.  I was thinking of buying two units and install them at the top of the engine with one closer to the front and the second closer to the back.  On the Lyco-Saurus the bottom of the engine has the intake and oil pan so I imagine the liquid and distance from the source of the sound would dampen out the sound.  When you order them they ask you for your cylinder diameter so they can tune the sensor to your engine.
 
The next question is…how do you test to see if the darn thing is working? 

Thanks,
Bill Hunter

 
From: owner-aeroelectric-list-server(at)matronics.com (owner-aeroelectric-list-server(at)matronics.com) <owner-aeroelectric-list-server(at)matronics.com (owner-aeroelectric-list-server(at)matronics.com)> On Behalf Of Robert L. Nuckolls, III
Sent: Monday, October 1, 2018 10:23 AM
To: aeroelectric-list(at)matronics.com (aeroelectric-list(at)matronics.com)
Subject: Re: Lycoming Knock Sensor


 
At 11:51 PM 9/30/2018, you wrote:
Quote:

I have never heard of a knock sensor on a Lycoming, even one with electronic mags. I don't see why you couldn't install one in any of the 1/8 NPT primer ports though.


  Knock sensors are specialized microphones
  mounted to some sturdy feature of the
  crankcase. The device is optimized to
  detect 'knock tones' in the 4-6 Khz range
  (determined by cylinder bore diameter).

  There are no plug-n-play sensors . . . i.e.
  devices that will light a bulb when knocking
  is detected. They all require some degree
  of signal conditioning to separate noises
  of interest from the rest. Here's on example
  of a product paired with a sensor that
  will illuminate an annunciator when knocking
  is detected.

https://tinyurl.com/y79tde7s

  There is a constellation of Arduino based
  sensor detection projects including sample
  software

https://tinyurl.com/hsq4mee

  This brings to mind another knowledge nugget
  I was offered at a Burlington CO fly-in about
  15 years ago. The legacy oxygen sensors used
  on automobiles have been demonstrated to function
  as advertised in 100LL engines. Met a fellow
  with an O2 sensor paired with a millivoltmeter
  on the panel.  He asserted that the sensor had
  several hundred hours on it and had not succumbed
  to the predicted 'lead fouling' that discouraged
  use on aircraft engines.

  One might consider an automotive O2 sensor as
  an adjunct for achieving consistent mixture
  settings. Here's a short article on how they
  work:

https://tinyurl.com/ybm74fvh

 



  Bob . . .





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dsleepy47



Joined: 15 Dec 2007
Posts: 40

PostPosted: Tue Oct 02, 2018 3:08 pm    Post subject: Lycoming Knock Sensor Reply with quote

Here is a link to a paper about setting up knock sensing with a link to an IC used for processing.

http://www.ti.com/lit/an/slyt580/slyt580.pdf

Deems Herring

________________________________________
From: owner-aeroelectric-list-server(at)matronics.com <owner-aeroelectric-list-server(at)matronics.com> on behalf of chris <csmale(at)bak.rr.com>
Sent: Tuesday, October 2, 2018 6:37 PM
To: aeroelectric-list(at)matronics.com
Subject: Re: Lycoming Knock Sensor

knock sensing is quite complex. Search efi101.com forums for posts on knock sensing. It will give you and idea of how to go about doing your proposal. csmale(at)bak.rr.com<mailto:csmale(at)bak.rr.com>

On 10/02/2018 12:42 PM, billhuntersemail(at)gmail.com<mailto:billhuntersemail(at)gmail.com> wrote:
Quote:
. . .wouldn't you want to mount the sensors such that their sense axis is in the same plane as the knock vibration; namely line up with the piston rods and not on top pf the engine case...?

I was kinda wondering the same thing.

If I had the money I would buy six knock detection systems and have one sensor per cylinderand if I did the questions would be:
-Should one knock sensor be installed on the sidewall of each cylinder?

-Or should one knock sensor be installed at the top of the cylinder head near the rocker cover?

I am realistically only going to install one or two knock sensors so does the ping sound get transmitted through the metal of the engine to be heard practically everywhere? If so then I imagine only one sensor installed on the crankcase split somewhere in the middle would be sufficient. Yes if you only have one sensor then you really do not know what cylinder is pinging however for my purposes I simply want to halt detonation ASAP and I do not really know care what cylinder.

Thanks,
Bill Hunter

From: owner-aeroelectric-list-server(at)matronics.com<mailto:owner-aeroelectric-list-server(at)matronics.com> <owner-aeroelectric-list-server(at)matronics.com><mailto:owner-aeroelectric-list-server(at)matronics.com> On Behalf Of skywagon185guy
Sent: Tuesday, October 2, 2018 10:47 AM
To: aeroelectric list <aeroelectric-list(at)matronics.com><mailto:aeroelectric-list(at)matronics.com>
Subject: Re: Lycoming Knock Sensor

. . .wouldn't you want to mount the sensors such that their sense axis is in the same plane as the knock vibration; namely line up with the piston rods and not on top pf the engine case...?

On Tue, Oct 2, 2018 at 9:09 AM <billhuntersemail(at)gmail.com<mailto:billhuntersemail(at)gmail.com>> wrote:
Gentlemen,

Thank you for your reply and sorry for the delay in my reply as I was flying all day yesterday.

Firstly...THANK YOU for your assistance on this...GREATLY APPRECIATED!!!

I have a Lycoming TIO-540 and I run LOP with balanced injectors.

I understand the concept of one sensor per cylinder and I also understand that the cylinders on the air-cooled aircraft engine is not as tightly connected to the engine block as a water cooled engine however sound travels through metal quite quickly and I would think that the sound would move from each cylinder head to the block.

Would not one sensor mounted on the crankcase hear the pings?

I can see if I only installed one sensor on the head of cylinder #1 and a pinging in cylinder #6 would have a long way to travel and the sound would distort so the sensor would be unreliable for any cylinder other than its installed #1 position.

The Knocksense unit that Bob posted is precisely the one that I was looking at. I was thinking of buying two units and install them at the top of the engine with one closer to the front and the second closer to the back. On the Lyco-Saurus the bottom of the engine has the intake and oil pan so I imagine the liquid and distance from the source of the sound would dampen out the sound. When you order them they ask you for your cylinder diameter so they can tune the sensor to your engine.

The next question ishow do you test to see if the darn thing is working?

Thanks,
Bill Hunter

From: owner-aeroelectric-list-server(at)matronics.com<mailto:owner-aeroelectric-list-server(at)matronics.com> <owner-aeroelectric-list-server(at)matronics.com<mailto:owner-aeroelectric-list-server(at)matronics.com>> On Behalf Of Robert L. Nuckolls, III
Sent: Monday, October 1, 2018 10:23 AM
To: aeroelectric-list(at)matronics.com<mailto:aeroelectric-list(at)matronics.com>
Subject: Re: Lycoming Knock Sensor

At 11:51 PM 9/30/2018, you wrote:
I have never heard of a knock sensor on a Lycoming, even one with electronic mags. I don't see why you couldn't install one in any of the 1/8 NPT primer ports though.

Knock sensors are specialized microphones
mounted to some sturdy feature of the
crankcase. The device is optimized to
detect 'knock tones' in the 4-6 Khz range
(determined by cylinder bore diameter).

There are no plug-n-play sensors . . . i.e.
devices that will light a bulb when knocking
is detected. They all require some degree
of signal conditioning to separate noises
of interest from the rest. Here's on example
of a product paired with a sensor that
will illuminate an annunciator when knocking
is detected.

https://tinyurl.com/y79tde7s

There is a constellation of Arduino based
sensor detection projects including sample
software

https://tinyurl.com/hsq4mee

This brings to mind another knowledge nugget
I was offered at a Burlington CO fly-in about
15 years ago. The legacy oxygen sensors used
on automobiles have been demonstrated to function
as advertised in 100LL engines. Met a fellow
with an O2 sensor paired with a millivoltmeter
on the panel. He asserted that the sensor had
several hundred hours on it and had not succumbed
to the predicted 'lead fouling' that discouraged
use on aircraft engines.

One might consider an automotive O2 sensor as
an adjunct for achieving consistent mixture
settings. Here's a short article on how they
work:

https://tinyurl.com/ybm74fvh

Bob . . .


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