Today's Message Index:
----------------------
1. 04:50 AM - Re: Knock sensors? (Ken)
2. 05:27 AM - Re: Knock sensors? (Kelly McMullen)
3. 05:32 AM - Re: Knock sensors? (Noel Loveys)
4. 06:43 AM - Re: Knock sensors (Gary Casey)
5. 06:48 AM - Re: Knock sensors? (Noel Loveys)
6. 03:06 PM - Re: Knock sensors? (Greg Young)
7. 04:20 PM - Re: Knock sensors? (Fiveonepw@aol.com)
8. 06:05 PM - Re: Re: Knock sensors (AzevedoFlyer@aol.com)
Message 1
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| Subject: | Re: Knock sensors? |
Surely ion sensing of detonation as Saab has been doing (with electronic
ignition) is cheaper to develop and more precise. Could be it will soon
be time to advance into the last century with these engines.
Ken
Fiveonepw@aol.com wrote:
> In a message dated 10/12/2007 8:27:32 PM Central Daylight Time,
> azevedoflyer@aol.com writes:
>
> Aircooled engines complicate things a bit because of the finning
> which radiate vibration in a very ample spectrum.
>
> >>>
>
> Based on my meager understanding of knock sensor physics in automotive
> applications, this was my primary suspicion- how to isolate specific
> "knock" signatures when you have several hundred fins vibrating in
> multiple frequencies and harmonics of same. If Lycosaurs were falling
> from the sky due to detonation at the hands of efficiency-desparate
> pilots, I'd believe market and/or regulatory pressure would force
> development of such a system. Perhaps when domestic airplane fuel
> hits European price$ and truly efficient operation becomes a defining
> market factor, this technology will develop and we'll have a new
> paradigm: LOD operation vs. LOP, just like in your average
> run-of-the-mill ten-year-old Nissan Sentra....
>
> With the astonishing capacity of modern digital processing, I can't
> understand how an on-board processor couldn't sample vibratation
> sendor data from multiple points, compare that against know "safe"
> data, then somehow annunciate a potentially unsafe condition and/or
> make appropriate adjustments to whatever engine-management scenario a
> pilot may employ in the ultimate interest of maximizing efficiency.
>
> Here's hoping that if observers from the Lycoming/Continental
> intelligentsia have comments, they'd chime in here, even if covertly.
>
> Appreciate the discussion-
> Mark
Message 2
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| Subject: | Re: Knock sensors? |
Wrong. Most aircraft engines being sold today are fuel
injected........mechanical, continuous flow. No computer involved,
pilot controls the mixture. For computer control, you have to develop
a mixture map for each variety of engine. Ain't gonna happen. Not to
mention that TCM and Lycoming oppose LOP operations, so they wouldn't
design for it.
On 10/14/07, David M. <ainut@hiwaay.net> wrote:
>
>
> if efficiency were truly a concern, they'd all convert to fuel injection.
> If that, then the pilot would have no control over anything except which way
> to point -- and would not need it. The computer would control LOP etc.
>
> David M.
>
>
> ----- Original Message -----
> From: Fiveonepw@aol.com
> To: engines-list@matronics.com
> Sent: Sunday, October 14, 2007 10:14 PM
> Subject: Re: Engines-List: Knock sensors?
>
>
> In a message dated 10/12/2007 8:27:32 PM Central Daylight Time,
> azevedoflyer@aol.com writes:
> Aircooled engines complicate things a bit because of the finning which
> radiate vibration in a very ample spectrum.
> >>>
>
> Based on my meager understanding of knock sensor physics in automotive
> applications, this was my primary suspicion- how to isolate specific "knock"
> signatures when you have several hundred fins vibrating in multiple
> frequencies and harmonics of same. If Lycosaurs were falling from the sky
> due to detonation at the hands of efficiency-desparate pilots, I'd believe
> market and/or regulatory pressure would force development of such a system.
> Perhaps when domestic airplane fuel hits European price$ and truly efficient
> operation becomes a defining market factor, this technology will develop and
> we'll have a new paradigm: LOD operation vs. LOP, just like in your average
> run-of-the-mill ten-year-old Nissan Sentra....
>
> With the astonishing capacity of modern digital processing, I can't
> understand how an on-board processor couldn't sample vibratation sendor data
> from multiple points, compare that against know "safe" data, then somehow
> annunciate a potentially unsafe condition and/or make appropriate
> adjustments to whatever engine-management scenario a pilot may employ in the
> ultimate interest of maximizing efficiency.
>
> Here's hoping that if observers from the Lycoming/Continental intelligentsia
> have comments, they'd chime in here, even if covertly.
>
> Appreciate the discussion-
> Mark
>
>
Message 3
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speaking only as an outsider there are two things that I see regarding
the
use of knock sensors.
First the engines are basically high volume low compression so they are
not
overly prone to knocking. Sure it can/does occur but not as often as on
higher compression engines.
The second point is any knocking would be fairly low in amplitude
compared
with a higher revving high CR engine.
Even so I think it is obvious that a knock sensor can be developed to
operate efficiently on these air-cooled engines. I'll bet they could
even
install knock sensors in the crank shafts that way sensors could do
double
duty as a form of torque meter as well as knock sensor.
Noel
-----Original Message-----
From: owner-engines-list-server@matronics.com
[mailto:owner-engines-list-server@matronics.com] On Behalf Of
Fiveonepw@aol.com
Sent: Monday, October 15, 2007 12:45 AM
Subject: Re: Engines-List: Knock sensors?
In a message dated 10/12/2007 8:27:32 PM Central Daylight Time,
azevedoflyer@aol.com writes:
Aircooled engines complicate things a bit because of the finning which
radiate vibration in a very ample spectrum.
>>>
Based on my meager understanding of knock sensor physics in automotive
applications, this was my primary suspicion- how to isolate specific
"knock"
signatures when you have several hundred fins vibrating in multiple
frequencies and harmonics of same. If Lycosaurs were falling from the
sky
due to detonation at the hands of efficiency-desparate pilots, I'd
believe
market and/or regulatory pressure would force development of such a
system.
Perhaps when domestic airplane fuel hits European price$ and truly
efficient
operation becomes a defining market factor, this technology will develop
and
we'll have a new paradigm: LOD operation vs. LOP, just like in your
average
run-of-the-mill ten-year-old Nissan Sentra....
With the astonishing capacity of modern digital processing, I can't
understand how an on-board processor couldn't sample vibratation sendor
data
from multiple points, compare that against know "safe" data, then
somehow
annunciate a potentially unsafe condition and/or make appropriate
adjustments to whatever engine-management scenario a pilot may employ in
the
ultimate interest of maximizing efficiency.
Here's hoping that if observers from the Lycoming/Continental
intelligentsia
have comments, they'd chime in here, even if covertly.
Appreciate the discussion-
Mark
_____
See what's new at AOL.com and
Navigator
and
http://www.matronics.com/Navigator?Engines-List
the
Web
===========
Message 4
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| Subject: | Re: Knock sensors |
Miguel,
Thought about taking it commercial? Sounds possible.
Gary
On Oct 14, 2007, at 11:56 PM, Engines-List Digest Server wrote:
>
>
> Time: 05:42:14 PM PST US
> From: AzevedoFlyer@aol.com
> Subject: Re: Engines-List: Re: Knock sensors
>
> Gary,
> It translates pressure measured through a modified Pitot Tube into
> flow.
> Thanks,
> Miguel
>
Message 5
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I've seen the term LOP used a few times..... But have no idea what it means.
Noel
> -----Original Message-----
> From: owner-engines-list-server@matronics.com
> [mailto:owner-engines-list-server@matronics.com] On Behalf Of
> Kelly McMullen
> Sent: Monday, October 15, 2007 9:51 AM
> To: engines-list@matronics.com
> Subject: Re: Engines-List: Knock sensors?
>
>
> <apilot2@gmail.com>
>
> Wrong. Most aircraft engines being sold today are fuel
> injected........mechanical, continuous flow. No computer involved,
> pilot controls the mixture. For computer control, you have to develop
> a mixture map for each variety of engine. Ain't gonna happen. Not to
> mention that TCM and Lycoming oppose LOP operations, so they wouldn't
> design for it.
>
Message 6
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LOP=lean of peak, ROP=rich of peak
Regards,
Greg Young
> -----Original Message-----
> From: owner-engines-list-server@matronics.com
> [mailto:owner-engines-list-server@matronics.com] On Behalf Of
> Noel Loveys
> Sent: Monday, October 15, 2007 8:43 AM
> To: engines-list@matronics.com
> Subject: RE: Engines-List: Knock sensors?
>
> <noelloveys@yahoo.ca>
>
> I've seen the term LOP used a few times..... But have no idea
> what it means.
>
> Noel
Message 7
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| Subject: | Re: Knock sensors? |
In a message dated 10/15/2007 8:52:18 AM Central Daylight Time,
noelloveys@yahoo.ca writes:
I've seen the term LOP used a few times..... But have no idea what it means.
>>>
Normally for injected engines- stands for Lean Of Peak. If using an EGT
gauge, leaning the mixture will cause EGTs to rise to a maximum, then begin to
fall until there is too little fuel to sustain combustion and the engine will
begin to run rough. ROP means Rich Of Peak. Most carbureted engines have less
even fuel distribution to each cylinder and the leanest cylinder will begin to
mis-fire before an EGT drop is usefully noted. This is a real rough cut on the
topic and there is a WHOLE lot more to this- look for articles by John Deakin
(sp?) on AvWeb for better info than you found here!
Mark
Message 8
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| Subject: | Re: Knock sensors |
Yes Gary.
However, right now I do not have the time!
Maybe a few years from now when I retire?
FAA people that supervised development is most enthusiastic and want me to
proceed to an STC and get it into the marked. From their point of view, safety
is greatly enhanced and that is enough incentive for them...
Cheers,
Miguel
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