EGT Pyrometer

[RavensRoost]

At weekend place (off grid), neighbor has a new-to-him propane-fueled 15KW generator that he thinks is using more fuel than it should. As we are at ~ 4250 ft ASL, it may be running rich. The manual says to set the mixture control for a specific Exhaust Gas Temperature under load (EGT, I do not know the temp, it is his manual and he could not remember temp, hope he can find manual when it comes time!).

When I google EGT and/or exhaust pyrometers I see several units e.g. Autometer, S-W, BullyDog etc. for dash or pillar mounting for about $150. Is there a portable unit that would be cheaper? Or at least one that would be suitable as an Digital Multi-Meter (DMM) accessory or adjunct?

He is on a fixed income. If it were for me, I would buy and mount the in-dash unit on the genny. As it is for him, I could justify purchasing a piece of "test equipment" for myself that could be used for his needs and various other uses for me over time.

Also, I am assuming the infrared thermometers or pyrometers would not really give an accurate reading of EGT, but I might be wrong. Input solicited.

RavensRoost

 

[brandoro]

I think a hand held temperature gun aimed at the end of the manifold connected to the exhaust pipe would give you a pretty close idea. If you take a reading every couple of minutes you will see the temperature stabilize, that should be what you need within very few degrees.
Just my opinion, free advice is worth every cent

 

[Diamondpilot]

I have to agree, get the hand held one from HF or some other source and it will get you very close.

Chris

 

[RavensRoost]

Thanks, have wanted an infrared thermometer for myself anyway. May end up with one either way!

Anyone have experience with checking EGT uisng a hand-held IR "gun"? Do you shoot at end of exhaust manifold where it empties into pipe/stack as Brandoro suggested -- sounds OK to me -- or do you shoot up the end of the pipe? I am guessing at manifold/stack junction, but may need to wait a few minutes after each adjustment for changes in temp, also as Brandoro suggested. How accurate of a reading can one get using this method?

RavensRoost

 

[E/S]

"Anyone have experience with checking EGT uisng a hand-held IR "gun"? Do you shoot at end of exhaust manifold where it empties into pipe/stack as Brandoro suggested -- sounds OK to me -- or do you shoot up the end of the pipe? I am guessing at manifold/stack junction, but may need to wait a few minutes after each adjustment for changes in temp, also as Brandoro suggested. How accurate of a reading can one get using this method?"

We shoot our dozen gen sets at work with Fluke IF guns on the exhoust pipe within a inch or two of the exhoust manifold. This works very well and is very accurate.

E/S

 

[Mace Canute]

Just a little reminder...the temperature range on infrared non contact thermometers varies greatly! Some go to just a few hundred degrees F and some go to a few thousand! If you want to shoot exhaust temperatures, you will probably want to have one that goes up to 2000F.
IR thermometers have so many uses! I love mine!

 

[RickB]

Just a little reminder...the temperature range on infrared non contact thermometers varies greatly! Some go to just a few hundred degrees F and some go to a few thousand! If you want to shoot exhaust temperatures, you will probably want to have one that goes up to 2000F.
IR thermometers have so many uses! I love mine!

Absurd. 1000 deg F is more than enough.

 

[RavensRoost]

"Anyone have experience with checking EGT uisng a hand-held IR "gun"? Do you shoot at end of exhaust manifold where it empties into pipe/stack as Brandoro suggested -- sounds OK to me -- or do you shoot up the end of the pipe? I am guessing at manifold/stack junction, but may need to wait a few minutes after each adjustment for changes in temp, also as Brandoro suggested. How accurate of a reading can one get using this method?"

We shoot our dozen gen sets at work with Fluke IF guns on the exhoust pipe within a inch or two of the exhoust manifold. This works very well and is very accurate.

E/S

Thanks E/S! Decided on Extech #42511 "Dual laser" unit, ordered and on the way. This unit reads up to 1100 F. I know my non-turbo diesel genny EGT is ~ 800 F and turbo diesels are < 1200 F, but do not know what EGT a propane fueled engine runs. Guess I wil find out....

RavensRoost

 

[KennedyDiesel]

Surface temp of the manifold will vary quite widely from actual EGT.

Some Fluke meters accept plug in from a K type thermocouple. This would save a bunch of the cost if you know someone with one of those.

 

[Diamondpilot]

Absurd. 1000 deg F is more than enough.

Not true. Measure the exhaust temps of a turbo diesel like a Powerstroke or a Dmax. They get in the 1200 deg range or more.

Chris

 

[RickB]

Not true. Measure the exhaust temps of a turbo diesel like a Powerstroke or a Dmax. They get in the 1200 deg range or more.

Chris

But an IR thermometer isn't measuring tru EGT, it will be reading whatever hard part it is pointed at.

 

[Redneck in training]

I have to agree, get the hand held one from HF or some other source and it will get you very close.

Chris

I bought infrared in Northern Tools for less than 20 bucks.
I have this one too
80TK Thermocouple Module (Type K)

 

[dfkrug]

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.

 

[KennedyDiesel]

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.

 

[dfkrug]

...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.

 

[RavensRoost]

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

 

[mostly_gas]

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.

 

[g82263]

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.

 

[Wayne_H]

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

 

[dex3361]

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.