What thermocouple type for EGT measurement ?
What thermocouple type for EGT measurement ?
(OP)
What is the most frequently used thermocouple type for exhaust gas temperature measurement for gasoline engines ?
There are all sorts of conflicting requirements including temperature measurement range, millivolt output, and life in oxidizing/reducing atmospheres.
I am just wondering what you guys are using ?
There are all sorts of conflicting requirements including temperature measurement range, millivolt output, and life in oxidizing/reducing atmospheres.
I am just wondering what you guys are using ?





RE: What thermocouple type for EGT measurement ?
RE: What thermocouple type for EGT measurement ?
I was wondering about suitability of K type, they have a nice high millivolt output, and survive o/k in a slightly oxidising atmosphere, and are relatively low cost and easy to obtain.
But is 2000F (1093C) really high enough on a flat out high specific power racing engine ? The thermocouple tables stop at 1370C. I know we definitely don't want to run lean, and there should be about zero oxygen, but I was hoping to be abe to measure up to higher temperatures. Is that a realistic wish ?
Do you slip your EGT thermocouples in a stainless steel well, or do you run it naked in the exhaust stream ? I can see advantages both ways.
RE: What thermocouple type for EGT measurement ?
www.omega.com
Nick
I love materials science!
RE: What thermocouple type for EGT measurement ?
You shouldn't see temps that high, unless something is wrong (like
retarded timing)
There is a tradeoff between response time and sensor lifespan.
Top Fuel Drags typically use naked end 1/4 in. dia. K type for EGT.
They won't last forever but they respond quickly.
Good success using 1/8 closed end K type for Road racing for multi-hour endurance racing...and the fitment on the exhaust to hold the sensor is smaller and easier to fit in place.
RE: What thermocouple type for EGT measurement ?
It looks like K type is the go then. They are cheap enough to keep replacing, and a naked thermocouple would respond almost instantly in a high velocity exhaust stream.
This is for an engine dyno, so thermocouple life is not a big issue.
RE: What thermocouple type for EGT measurement ?
RE: What thermocouple type for EGT measurement ?
You can also buy clips that you crmp on the end and the couple lasts even longer. Although if you are looking for minimum response time you might want to find a way to make teh really little tiny weld beads of alumel and chromel that are on omega's fastest responding TC. I have some that are made with wire <0.012" dia and w/ a bead on the end that is <0.020".
nick
RE: What thermocouple type for EGT measurement ?
RE: What thermocouple type for EGT measurement ?
This worked well for me using ~22 ga. t/c wire, and with 27 vdc and about 1 F of total capacitance. I found the "best" combination by starting with a bunch of 10,000-25,000 uF cap's from junked power supplies, and ganging them in parallel until I was happy with the results.
Good luck,
Ben T