Definition
A heat exchanger fitted between the turbocharger (or supercharger) and the engine's induction system that cools the compressed induction air before it enters the cylinders. Compressing air raises its temperature, which reduces its density and increases the risk of detonation; the intercooler removes that added heat by passing the charge air through a core cooled by ram air, restoring density and lowering cylinder head temperatures.
Plain English
A small radiator that cools the hot, squeezed air coming from the turbocharger before it goes into the engine. Cooler air is denser, so the engine makes more power and is less likely to suffer damaging knock.
Context Anchor
Seen in discussions of turbocharged and supercharged aircraft engines, especially engine temperature, power, and intake-air systems.
Derivation
From 'inter' (between) and 'cooler.' The name describes its position: it sits between two stages — between the turbocharger and the engine — and cools the air passing through it.
Why Pilots Care
Lower intake temperature reduces detonation risk and allows higher boost without engine damage.
Analogy
It is like letting hot, compressed air pass through a small radiator before the engine uses it.
Intuition Check
An intercooler is not mainly for cooling the whole engine. It cools the intake air after it has been compressed.
Example Sentence 1
The intercooler dropped the induction air temperature by nearly 90°F before it reached the cylinders, helping keep the engine well clear of detonation on the climb.
Example Sentence 2
Mechanics checked the intercooler for leaks during the preflight inspection of the turbocharged aircraft.