Carb Heat Control

First I'll tell you that I don't have the faintest Idea of what you need.
Does this help at all.

http://www.open.org/~thomas/asr/profiles_C172.htm

And this :
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Do I need carb heat in the 172?

I've not logged this with TRI and to be fair it may be my lack of experience
with the real 172R (I've only flown N and P). However, in the 172R cockpit
(and any of the other pistons for that matter), I couldn't find a Carb Heat
control. I've tried using 'H' which, according to my manual is the Carb Heat
key, and there is no discernible change in the engine RPM for a 172.
It may be that the (fuel injected?) 172 (and Malibu for that matter) doesn't
need Carb Heat. Is that the case?

You are correct.

XXXXX

Your hypothesis is correct. The new 172's have a fuel injected Lycoming engine
so there's no carburetor. No carburetor means no venturi with moist air to
freeze, thus no need for carb heat.
The terms here may be incorrect, it's been a while since my instructor yelled
"PULL THE CARB HEAT"!!!
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I fly the 172 for real, and it has carb heat, being that it has a carb. All 150's have carb heat. The new 172's do not have heat as they are fuel injected, however most injected planes have an alternate air valve in case of airframe icing.