A basic engine with the addition of a supercharger.
A supercharger is any device that pressurizes the air intake to above atmospheric pressure. Both super- chargers and turbochargers do this. In fact, the term "turbocharger" is a shortened version of "turbosuper- charger," its official name. The difference between the two devices is their source of energy. Turbochargers are powered by the mass-flow of exhaust gases driving a turbine. Superchargers are powered mechanically by belt- or chain- drive from the engine's crankshaft. An ordinary four-stroke engine dedicates one stroke to the process of air intake. There are three steps in this process: 1. The piston moves down. 2. This creates a vacuum. 3. Air at atmospheric pressure is sucked into the combustion chamber. Once air is drawn into the engine, it must be combined with fuel to form the charge -- a packet of potential energy that can be turned into useful kin- etic energy through a chemical reaction known as combustion. The spark plug initiates this chemical reaction by igniting the charge. As the fuel under- goes oxidation, a great deal of energy is released. The force of this explosion, concentrated above the cylinder head, drives the piston down and creates a reciprocating motion that is eventually transferred to the wheels. Getting more fuel into the charge would make for a more powerful explosion. But you can't simply pump more fuel into the engine because an exact amount of oxygen is required to burn a given amount of fuel. This