The concept of forced induction is easily explained with the “suitcase analogy”. Running out of space in our suitcases is a common occurrence when traveling. While it’s logical for us to simply get a second bag, we unpack and try to squeeze in as much luggage into the first bag as possible, in order to avoid the hassle of a second bag altogether.
This ‘more efficient’ packing allows us to haul extra luggage (and shop more, if we’re on vacation) without requiring an extra bag.
The same concept can be applied to engines. In theory, an engine can only pack in so much air-fuel mixture to help it generate its rated power. To make more power, one must ideally look for a bigger engine, but forced induction can help “cheat” by squeezing more charge into the same space, thereby helping to burn more fuel and generate more than the rated power.
As stated earlier, air compression is achieved by means of a device called a supercharger.
Superchargers are mechanical pumps that compress air and feed it to the intake manifold (the passageway through which a combustible charge enters the combustion chamber in the engine).
Pumps need power to run, and a supercharger is no different. The supercharger will derive power from the engine using a pulley and a belt to compress the air and feed it back. However, just like the supercharger, many other vital functions, such as air conditioning and power steering, are dependent on the engine itself. A supercharger therefore adds to the load on the engine, which offsets the benefits. This encouraged the development of the turbocharger, a device that does not rely on engine power, but rather on exhaust gases!