after cat EGT

[Tmoose]

Any ideas what the Exhaust Gas Temperature is likely to be immediately after the cat on a good/well running passenger car at 25 mph or highway speeds?

This place implies ~ 900 K ~ 1125 F

http://www.flirthermography.com/media/2003_PastorFINAL.pdf

Thanks

 

[SBBlue]

I suspect there are too many variables to be able to give you a universal engine.

What size engine are we talking about? What will be the power output of the engine at 25 mph? 50%? or 20%? This will make a big difference in how much heat is absorbed by the exhaust manifold and engine block.

How about the ambient temperature? The air flow past the engine/manifold? What's the amount of insulation around the cat? Is there insulation around the exhaust manifold? Is a turbocharger in use? Does the engine use ultralean combustion (such as stratified charge combustoin) or is it a much more conventional stoichometric engine?

 

[franzh]

In order to calculate the temps, an exhaust catalyst design engineer would need info like:
Engine size and RPM (flow)
Exhaust inlet temp;
Catalyst internal volume;
Catalyst formulation;
Catalyst construction (honeycomb, pellet, asymmetric grid);
Exhaust composition at inlet;
Catalyst efficiency target;
Air injection;
2 bed or 3 bed cat;
What fuel will be used?
As SBBlue stated, air fuel ratios;

One more thing, what have you done to determine the results? The weblink you provided does not work.

Franz

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[Tmoose]

"One more thing, what have you done to determine the results? "

I read the results in Figure 3 at

http://www.flirthermography.com/media/2003_PastorFINAL.pdf

. I got that link just by looking for "catalytic converter exhaust temperature" with a Google image search. At 4:30 EST Thursday the PDF at the link came up quick. It is the results of a collaborative study done by Renault and the University Politecnica at Valencia


My question was prompted by a newsgroup post by someone whose car flunked an emission test, and part of the failure report was EGT of 2500.

 

[GregLocock]

2500.... hmm

Well the good news is that if that is correct they won't have to worry about emission tests for long, as the whole car is on fire!

Cheers

Greg Locock