When air is heated, it becomes less dense and looses oxygen. In an engine this can cause several problems. The most common problem is a loss of efficiency. Other problems can include wear and heat damage to the engine block and engine knocking caused by air pockets in the air being fed for combustion.
In an engine, an inter cooler offsets the excess heat caused by supercharging or turbo charging an engine. When air is cooled, it becomes more dense. This increased density allows more air and fuel to be combusted per engine cycle, which ultimately increases the output power of the engine.
Technically an inter cooler is a device used between stages of supercharging or turbo charging to cool the air for use in the next stage. If the device is used at the end of the supercharging cycle, it is called an after cooler. Despite this distinction, the two names are often used interchangeably.
The size and design depends on the engine in which the inter cooler is installed. Many modern automobiles have inter coolers or after coolers. They are also found in aircraft and other high-power engines.
An air-to-air inter cooler works by passing hot engine air through tubes. This air is cooled by heat transfer, as cooler air passes by outside the tubes. Where the inter cooler is mounted on the engine determines the efficiency of the cooling system.
Front-mounted systems are most effective. They sit at the front of the car, where the forward motion of the car can force air through the system. This results in a constant supply of cool air.
Top-mounted systems are slightly less effective. They sit on top of the engine, which allows more heat from the engine to affect the inter cooler system, as heat rises. Also, this setup does not provide a built-in source of cool air. Many mechanics get around this problem by installing a hood scoop, a raised opening in the hood that allows air to pass into the engine space.
An air-to-water inter cooler works by transferring the heat from engine air into water. Once the water is heated, it travels away from the hot parts of the engine. It then transfers heat into the outside air.