EGT Pyrometer

   / EGT Pyrometer #13  
When the Raytek handheld laser infrared thermometers came out years ago,
I was drooling over them for a long time. The ones that went up to over
1000F were VERY expensive, while the ones that topped out at less than
that eventually went under $100.

I bought the HF laser unit a few years ago, and I am quite happy with it.
(I just diagnosed an electrical service neutral problem with it.) I also
use it to detect misfires on multicylinder engines. It has proven to be
very precise and repeatable when I am able to get 8" away from the
laser spot on a fixed surface.

I am interested in how efficient you can make one of those standby
gensets as I know of a couple of owners of automatic b/u units that
run on propane and are VERY expensive to operate.
 
   / EGT Pyrometer #14  
If you know someone with a portable sniffer you'd do really well to try to set to a specific o2 sensor reading.

You will not get accurate readings in temp from a non contact thermometer, BUT everyting is relative so you can watch for a change in temp as adjustments are made. Just watch for consistency and stable readings before you start to adjust. A try K type thermocouple will be quite stable where the IR will vary with beam placement surface finish (emissivity) and spot size.
 
   / EGT Pyrometer #15  
...everything is relative so you can watch for a change in temp as adjustments are made.

I agree, you are looking for relative temps when using non-contact
thermos. Every one of these guns has a lens and an ideal focal point
for getting consistent accurate readings. For mine it is 8". Some of
the really cheap guns have no laser and non-optimal focal points.
 
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   / EGT Pyrometer
  • Thread Starter
#16  
Been doing some googling/reading and it may be that the IR thermo I ordered might be a goof on my part, may not go high enough: 1100 F max. Not a big issue to me because as others have offered, I will have many uses for it even if EGT is not its forte.

Scenario: fixed location 1800 RPM LPG-fueled genny at off grid location primarily used for pumping water, and also sometimes for charging batteries [15KW is way overkill for charging batts, but that is another issue.]

My plan so far is to shoot at the exhaust pipe immediately after the exhaust manifold and get an "as is" baseline temp under load (5hp well pump), then adjust mixture leaner, ensure frequency is stable, observe temp, (expect decrease), test cold start next day. Repeat as needed.

My understanding is less propane (leaner) = lower EGT. If that is correct, then the best efficiency should be at lowest EGT that yields a stable freq under load while still getting good cold starts. May take a few sessions.

Thanks for the collective input.

RavensRoost
 
   / EGT Pyrometer #17  
My plan so far is to shoot at the exhaust pipe immediately after the exhaust manifold and get an "as is" baseline temp under load (5hp well pump), then adjust mixture leaner, ensure frequency is stable, observe temp, (expect decrease), test cold start next day. Repeat as needed.

My understanding is less propane (leaner) = lower EGT. If that is correct, then the best efficiency should be at lowest EGT that yields a stable freq under load while still getting good cold starts. May take a few sessions.

Thanks for the collective input.

RavensRoost

Don't be surprised if EGT rises before falling. When adjusting mixtures on aircraft (recip pistons) to EGT gage mixture would be too rich and as the engine got leaned the EGT would rise. Depending on engine the aim point would be peak or 50 deg. past (lean side) peak. Another thing to think about is going too lean may damage engine. My uncle had a top overhaul after 600 hour an an engine that normally went about 1800+ hours. Mechanic said the damage was from excessive leaning.
 
   / EGT Pyrometer #18  
the best way to set this engine up is to use a monitor that allows you to set the fuel system by oxgyen content in the exhaust stream. the manufactuer should be able to give you the proper setting for that engine at the altitude your at. you also need to set the fuel regulator to the proper setting, this is done i inches of water and you need a manometer to do it. you can set the engine up for max horsepower or economy, the choice is yours. you can set it up by exhaust temp but i dont recomend it. if if the 02 is not set right it could result in detonation or valve life will be greatly diminished.
good luck.
 
   / EGT Pyrometer #19  
You had the clue a few posts back... Almost everyone who runs diesel engines in their trucks today and does any kind of mods runs an EGT gauge to make sure we don't melt our pistons down... I installed one in my 88 7.3 diesel, and it is a good tool.

The important take away is that the EGT you measure changes depending where you place the sensor. I'm using one by Isspro (very popular with the diesel truck crowd) and I know if I move it five inches back the measured temps drop off greatly. So I have to imagine the EGT they specified came with a location to measure, of possibly the exhaust header has a sensor hole?

Good luck!

Wayne
 
   / EGT Pyrometer #20  
If you want to get a more accurate reading with a IR thermometer put a piece of scotch 33 electrical tape on whatever you are reading. If it is to hot for tape use black paint. The shiny metal surface will give a false reading because it has a low emissivity (ability to emit IR light). The fixed emissivity of most of the cheaper IR guns is +-.9 and that is what Scotch 33 is and most high temp spray paint is the same emissivity +-.9. By converting the surface to a known emmisivity your temp reading will be much more accurate.
 

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