Measuring temperature drop from an intercooler

[Chris Smith]

Most thermistors will handle the ranges you need, and can be made to read out the temperatures relative over a small amount of response time.

For more accuracy over time the “hot wireâ€

[Engineer1138]

Craig:
Just use two thermocouples. You can buy thermocouple wire from Omega or find some on surplus market and make your own cheaply. You shouldn't need a Cold Junction compensating circuit because you don't care about the absolute temperature, you just care about T1-T2 so the cold sides will cancel out. As long as the "cold junction" of both thermocouples are the same temperature, you will be fine.

[GoingFastTurningLeft]

[quote="Chris Smith"]All of the turbo intercoolers I have worked are in the grill cooling down the incoming air, but that isn’t the point.

Your trying to measure the turbo via the intercooler, that’s irrelevant.

You mention Intercooler efficiency.

The turbos heat is a set of numbers on its own, based on other factors.

You measure the intake of the intercooler VS the exhaust of the intercooler, be it before or after the turbo as you looking for efficience of the intercooler working, not how much the turbo it self will raise temperature depending on load or speed.

The intercooler is simply a “efficiencyâ€

[Bob Scott]

If it were a belt-driven supercharger, then it wouldn't matter if it was before or after.

PV=nrT

Of COURSE it matters. Compression causes the majority of the heat, not the method by which a supercharger or turbocharger is driven.

Bob

[Chris Smith]

All turbo chargers are Exhaust gas driven.

However after the hot exhaust gas expands in the first turbo chamber and spins its shaft extremely fast, this spin is transferred down the shaft to a second turbo chamber which then compresses clean air ready for the intake of the cylinder.

Only a tiny amount of heat is transfered in this action simply because of its location. All the parts get hot.

However some turbos incorporate heat shields to minimize this small heat transfer.

The exhaust heat is NOT a factor of the fresh air temperature other than by minor accident and it is a small amount of heat transferred simply because of its location.

The exhaust heat is NOT a factor of the turbo charged air temperature.

Compression does that.

Same as any air compressor, when the air is compressed it heats up. Just feel the temperature of any air compressor tank. Its warmer than the air it took in.

Super chargers running off belts also heat up the air just the same, but perhaps a tiny bit less because they can locate the charger further away from the exhaust.

However it is a tiny component of the over all heat as the exhaust is not part of the main problem.

[Craig]

Just use two thermocouples. You can buy thermocouple wire from Omega or find some on surplus market and make your own cheaply. You shouldn't need a Cold Junction compensating circuit because you don't care about the absolute temperature, you just care about T1-T2 so the cold sides will cancel out. As long as the "cold junction" of both thermocouples are the same temperature, you will be fine.

I think I may do that. We use thermocouples all the time at work, so we have tons of wire (J type) and also have the machine to fuse the end together.

I have been reading up on thermocouples and cold junction compensators. I have found some CJC's pretty cheap that even come with a matched amplifier (http://www.linear.com/pc/productDetail. ... 1073,P1181).

I still need to do more reading to get a complete understanding on how it all works, but I think I should be able to come up with something soon. I'll look into using the cold-side of the intercooler as the cold junction since the cold junction is just a referance point anyways.

Interesting stuff, so much to learn!

[Dave Dixon]

I hate to sound like a broken record..... BUT. If you haven't checked them out, Omega has an excellent free hardcover book on Temperature Measurement. I reference it often, and it is very well written, as it starts with the basics. Did I mention that it is FREE? They even pay for shipping. Check out omega dot com, and click on the link for free handbooks.
Dave

[GoingFastTurningLeft]

If it were a belt-driven supercharger, then it wouldn't matter if it was before or after.

PV=nrT

Of COURSE it matters. Compression causes the majority of the heat, not the method by which a supercharger or turbocharger is driven.

Bob

I sit corrected.

You'd think extremely hot exhaust gas would contribute more than the compression. You learn something new everyday.

[GoingFastTurningLeft]

http://www.omega.com/literature/domestic.html

New 6th edition of the temperature handbook released march 7th. Appears to be a Parts Catalog and Technical literature.

Also appears that the "The OMEGA® Temperature TECHNICAL Handbook" is just excerpts from the 5th edition of the temperature handbook. http://www.omega.com/literature/temptechmmv/

[Craig]

Thanks for info about Omega, I have sent away for their books!