SUPERCHARGERS

Superchargers are engine-driven air pumps that force the air and fuel mixture into the engine. They are made in three basic configurations: centrifugal, Roots, and vane.

Figure 1-32.-Turbocharger.

Figure 1-33.-Superchargers.

Centrifugal Supercharger

The centrifugal supercharger (fig. 1-33, view A) has an impeller equipped with curved vanes. As the impeller is driven by the engine, it draws air into its center and throws it off at its rim. The air then is pushed along the inside of the circular housing. The diameter of the housing gradually increases to the outlet where the air is pushed out to the engine intake system.

Roots Supercharger

The Roots supercharger (fig. 1-33, view B) is a positive displacement type of supercharger that consists of two rotors inside a housing. As the rotors are driven by the engine, air is trapped between them and the housing. The air is then carried to the outlet where it is discharged. Because of the extremely narrow clearance between the rotors and the housing, this supercharger is very sensitive to dirt.

Vane Supercharger

The vane supercharger (fig. 1-33, view C) is a positive displacement supercharger that has a rotor that revolves in a body, the bore of which is eccentric to the rotor. Two sliding vanes are placed 180 degrees apart in slots in the rotor and are pressed against the body bore by springs in the slots. When the shaft is rotated, the vanes pick up air at the inlet port and carry it around the body to the outlet side where the air is discharged to the intake system of the engine.