A heat exchanger which reduces the temperature of the compressed air before it enters the combustion chamber
An intercooler is a special radiator through which the compressed air passes to cool it off before it enters the cylinder. This can only be found in turbocharged engines, as compression heats the air up, and normally aspirated engines do not have to cope with extra warmed up air.
A device which cools the air entering the carburetor or fuel injection system. Colder air has more oxygen molecules than warm air. Thus cooler air gives more power and better fuel economy. An intercooler looks like a radiator. It contains large passages for the intake flow, and uses either outside air or water directed over it to lower the temperature of the intake flow inside. Also called a charge-air cooler.