Okay, let’s talk about the Intercooler. Possibly the most argued about, and misunderstood, car component there is, short of the humble blow-off valve (which we’ll discuss another time).
The internal combustion engine that we all know and love is known by industrial engineers and science-types as a heat engine.
The torque that a car engine produces is a function of the difference between the temperature of the air headed into the engine, versus the temperature of the gasses inside the engine at combustion point.
This is why your car tends to perform better on a cool night than it does during a hot afternoon.
In a turbocharged or supercharged engine variant, the intake charge fed into the car is being compressed, and therefore, heated.
Put simply, an intercooler is put in place to lower the intake charge temperature. This effectively means more of a difference between the air temperature going in and the temperature of the air being combusted. Which means more torque per cylinder cycle ending up at the crank. Which means more power.
There’s also the benefit that colder air is denser, which means there are more gasses for the engine to burn each time it draws air in.
At it’s heart, an intercooler is the same as a radiator. They are both heat exchangers.
The radiator of a car draws heat away from the engine by way of coolant via a water jacket. It passes the coolant through a matrix that has air flowing through it. The air picks up the heat and dissipates it into the atmosphere around the radiator.
The more airflow there is over this radiator, the more heat is dissipated, and the better the whole thing works at keeping the engine cool. Which is why most cars have fans, for when there is less airflow headed past them.
On a turbocharged engine, with an air to air intercooler, the intercooler works exactly as described for the radiator above.
On a turbocharged or supercharged engine fitted with a water-to-air intercooler, the process is basically the reverse. In that, instead of air cooling the liquid, the coolant inside the intercooler cools the incoming air before it is swallowed by the engine.
There are many more advanced discussions that could be had about flow rates vs cooling density rates and such, but we’ll try to keep this relatively light at this point.
Michael Adams from Test Driven Australia
Article Originally Written for Infinite-Garage