Air fuel ratio 02 sensors for data

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Re: Air fuel ratio 02 sensors for data

Post by joe 90 » Mon Sep 11, 2017 4:37 pm

Belgian1979 wrote:
Firedome8 wrote:does pre ignition knock ?
No, but it sure does heat up things and that could lead to...:lol:
It melts pistons and shows up on an EGT gauge (goes down).
Not on a knock sensor but pre ignition will turn into knock then can be sensed.

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Re: Air fuel ratio 02 sensors for data

Post by The Radius Kid » Mon Sep 11, 2017 5:43 pm

joe 90 wrote:
Belgian1979 wrote:
Firedome8 wrote:does pre ignition knock ?
No, but it sure does heat up things and that could lead to...:lol:
It melts pistons and shows up on an EGT gauge (goes down).
Not on a knock sensor but pre ignition will turn into knock then can be sensed.
That sounds like David's scenario #2.
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Re: Air fuel ratio 02 sensors for data

Post by smeg » Mon Sep 11, 2017 6:12 pm

smeg wrote:If anyone is interested I have a good little used Innovate LM12 for sale, can log up to 12 wideband AFR and log other things like oil pressure, rpm, etc.
Sorry everyone, I had the wrong name, it is an innovate ST-12

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Re: Air fuel ratio 02 sensors for data

Post by Firedome8 » Mon Sep 11, 2017 9:50 pm

joe 90 wrote:
Belgian1979 wrote:
Firedome8 wrote:does pre ignition knock ?
No, but it sure does heat up things and that could lead to...:lol:
It melts pistons and shows up on an EGT gauge (goes down).
Not on a knock sensor but pre ignition will turn into knock then can be sensed.
many moons ago I have seen 2 stroke kart engines hole pistons, the driver would say the exhaust temp went down a couple hundred deg so he quick leaned it out!!! twallllllll and stop. had to learn that lesson a few times and often wondered Wtf was going on thought about it for 30 years,,never was sure !

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Re: Air fuel ratio 02 sensors for data

Post by nhrastocker » Mon Sep 11, 2017 10:28 pm

joe 90 wrote:
redliner wrote:
Warp Speed wrote: How do you come up with an EGT target temp?
EXACTLY!!!!!
Through testing and tuning.

EGT is always hottest at a lambda of 1.
No excess of air and no excess of fuel,it's all being used.
It's cooler when lean and it's cooler when rich.

As to how hot, it depends on the engine, fuel type, RPM and load.
Full throttle is hotter than part throttle, peak torque RPM is hotter than higher or lower RPM.

That's all when the timing is tuned correctly.
Less timing advance will be hotter, more timing advance = broken.
That's what the knock sensor is for.


How about piston engined aircraft?

WB 02 or EGT?

https://aviation.stackexchange.com/ques ... ch-or-lean
Yep, this confirms you lack of knowledge on how EGT works in aircraft reciprocating piston engines.
Like Jay (Warp Speed) stated, EGT's in aircraft reciprocating piston engines, does not determine performance or engine condition, it just shows operational limits that vary and dependent on aircraft take off weight and weather.

Educate yourself and read the article shown below that debunks your EGT theories.

http://www.gami.com/articles/egt_myths.pdf

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Re: Air fuel ratio 02 sensors for data

Post by joe 90 » Tue Sep 12, 2017 3:29 am

nhrastocker wrote:
Yep, this confirms you lack of knowledge on how EGT works in aircraft reciprocating piston engines.
Like Jay (Warp Speed) stated, EGT's in aircraft reciprocating piston engines, does not determine performance or engine condition, it just shows operational limits that vary and dependent on aircraft take off weight and weather.

Educate yourself and read the article shown below that debunks your EGT theories.

http://www.gami.com/articles/egt_myths.pdf

Which part?
I've already read that article.


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Re: Air fuel ratio 02 sensors for data

Post by carmakerevive » Tue Sep 12, 2017 9:48 pm

Belgian1979 wrote: Over the time that I've been a member and have seen you comment, I have seen more wrong things written by you than correct things. Others have already demonstrated that more than once.
Not sure who this was directed at sorry?
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Re: Air fuel ratio 02 sensors for data

Post by n2xlr8n » Wed Sep 13, 2017 7:10 am

Nice article.

To clarify, some factory ECUs use a knock sensor to control timing (in my case, Subaru). I used a EGT sensor to see if the ECU was pulling timing.
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Re: Air fuel ratio 02 sensors for data

Post by David Redszus » Wed Sep 13, 2017 11:38 am

Since the OP was with regard to O2, I'd like to pose a question.

We know that stoich means a perfect a/f ratio where all the air is combusted with all available fuel.
But a stoich a/f ratio does not produce best power; we need to go slightly richer than stoich.

Why does that work?
If we have already consumed all available air, the additional fuel does not have any air available to burn.
How can it then make more power?

Note that I am using the term "air" as a surrogate for oxygen.

Why does fast sample rate O2 data look like hash?

Why are EGTs all over the place?

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Re: Air fuel ratio 02 sensors for data

Post by Firedome8 » Wed Sep 13, 2017 11:52 am

David Redszus wrote:Since the OP was with regard to O2, I'd like to pose a question.

We know that stoich means a perfect a/f ratio where all the air is combusted with all available fuel.
But a stoich a/f ratio does not produce best power; we need to go slightly richer than stoich.

Why does that work?
If we have already consumed all available air, the additional fuel does not have any air available to burn.
How can it then make more power?

Note that I am using the term "air" as a surrogate for oxygen.

Why does fast sample rate O2 data look like hash?

Why are EGTs all over the place?
Extra fuel to make sure all oxygen is consumed and help cool the combustion chamber , in a carburetor setup to make sure no cylinder is lean ?

the hash due to pulsed flow, inconsistency in ignition lag time, and distribution error.

uneven combustion ,slow response sensors , and varied ignition lag time ?

not sure.

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Re: Air fuel ratio 02 sensors for data

Post by joe 90 » Wed Sep 13, 2017 4:38 pm

David Redszus wrote:Since the OP was with regard to O2, I'd like to pose a question.

We know that stoich means a perfect a/f ratio where all the air is combusted with all available fuel.
But a stoich a/f ratio does not produce best power; we need to go slightly richer than stoich.

Why does that work?
If we have already consumed all available air, the additional fuel does not have any air available to burn.
How can it then make more power.
It's because there's 3 different main chemical reactions happening each of which liberates different amounts of energy.
By providing an excess of fuel, you get more of the first and less of the third.

C + 1/2 o2= CO.......most energy.
CO + 1/2 o2 = CO2
H2 + 1/2 O2 = H2O.....least energy

With a lambda of 0.85 you have emissions of H2 and CO due to incomplete combustion but you shouldn't have soot.
If you go richer, you'll have soot too.

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Re: Air fuel ratio 02 sensors for data

Post by The Radius Kid » Wed Sep 13, 2017 5:36 pm

David Redszus wrote:Since the OP was with regard to O2, I'd like to pose a question.

We know that stoich means a perfect a/f ratio where all the air is combusted with all available fuel.
But a stoich a/f ratio does not produce best power; we need to go slightly richer than stoich.

Why does that work?
If we have already consumed all available air, the additional fuel does not have any air available to burn.
How can it then make more power?

Note that I am using the term "air" as a surrogate for oxygen.

Why does fast sample rate O2 data look like hash?

Why are EGTs all over the place?
You sure love poking the bear,don't you?
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Re: Air fuel ratio 02 sensors for data

Post by Warp Speed » Wed Sep 13, 2017 6:55 pm

The Radius Kid wrote:
David Redszus wrote:Since the OP was with regard to O2, I'd like to pose a question.

We know that stoich means a perfect a/f ratio where all the air is combusted with all available fuel.
But a stoich a/f ratio does not produce best power; we need to go slightly richer than stoich.

Why does that work?
If we have already consumed all available air, the additional fuel does not have any air available to burn.
How can it then make more power?

Note that I am using the term "air" as a surrogate for oxygen.

Why does fast sample rate O2 data look like hash?

Why are EGTs all over the place?
You sure love poking the bear,don't you?
LOL

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Re: Air fuel ratio 02 sensors for data

Post by Belgian1979 » Sat Sep 16, 2017 6:33 am

carmakerevive wrote:
Belgian1979 wrote: Over the time that I've been a member and have seen you comment, I have seen more wrong things written by you than correct things. Others have already demonstrated that more than once.
Not sure who this was directed at sorry?
Not towards you :D

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Re: Air fuel ratio 02 sensors for data

Post by Belgian1979 » Sat Sep 16, 2017 6:34 am

David Redszus wrote:Since the OP was with regard to O2, I'd like to pose a question.

We know that stoich means a perfect a/f ratio where all the air is combusted with all available fuel.
But a stoich a/f ratio does not produce best power; we need to go slightly richer than stoich.

Why does that work?
If we have already consumed all available air, the additional fuel does not have any air available to burn.
How can it then make more power?

Note that I am using the term "air" as a surrogate for oxygen.

Why does fast sample rate O2 data look like hash?

Why are EGTs all over the place?
Cooling of incoming charge due to the heat it takes to vaporate the extra fuel, with a higher density and more power as a consequence.

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