Exhaust Temperature ??


Thread Starter

Mark Hill

Has anyone measured the temperature of diesel engine exhaust gases ??

I'm interested in learning about available sensors.

Mark Hill

Warren Postma

Permanent feature or temporary diagnostic tool?

We have used infrared thermal-imaging systems before. There must also be special purpose thermocouples for this, I assume.


Colin Walker

Having worked in a number of power stations that use diesel generators from 500kW-16MW, all diesels have had J or K type thermocouples in each port to enable fuel rack adjustment. Note K TCs far superior. All TCs were in thermowells, (slow but effective).
Regards Colin
Hi Mark,

I drive a diesel truck and, being a member of "The Diesel Page", I feel obligated to link you to there for a starting point ;o)

Visit "The Link Exchange" (on the main page) for links to various manufacturers that may have some info for you about pyrometers as they relate to diesels.


- Eric Nelson
[email protected]
Packaging Associates Automation Inc. [email protected]
Rockaway, NJ, USA
I know that General Aviation airplanes (Cessna, Piper, etc.) all use exhaust gas temperature guages. I believe the probes (thermocouples) are
normally placed thru small holes directly into the engine exhaust flow. There are several companies that sell them.
Thanks Warren;

I'm looking for a permanent installation that can be connected to an A/D converter (datalogger) for subsequent analysis.


adrian wilson RR Donnelley and sons

Try going to many of your Automotive specality places for exhaust gas temperture mesurement devices. Racer's use them all the time to check for predetonation. The same priciple applys here, lean fuel conditons increased exhust temp. I also
was trying to find the web address of Cosra instruments, if you can find them they make recording equipment and sensors, just for the automotive style enviroment.
For engines about a certain power, it requires to measure the exhaust temperature to ensure to work below the design and normally controlled with
a circuit that limits the fuel into the burners. Basically it is a set of 6 or 8 T/C's with thermowell type K and installed around the stack.
Hopes this helps you,
Jose Chong

David P McConnell

If the diesel engine in question is of any size, the manufacturer will have exactly what you need as standard accessory. EGT is a critical measurement in that it is the first indication of overload of the engine. Prolonged overload is obviously destructive to the engine and turbocharger (if there is one).

EGT Measurement is also useful on larger engines in setting up the injected fuel quantities. Finally it is a good diagnostic tool to determine when a given cylinder is down on power, etc in time to take corrective action and limit damage.

If the engine is a large commercial type it would normally have thermocouple probe ports tapped into the exhaust manifolds adjacent to each exhaust port. If the engine is a smaller type the need for EGT measurement is dependent on the service in which the engine is employed. If there is a load limiter such as a circuit breaker on a driven generator, you may not need to be

A number of respondents have correctly (again IMHO) that a Type K TC in a thermowell is the correct approach. The TC will not last long directly exposed to the hot exhaust gasses.

My two cents worth!
Dave McConnell