Handbook of Turbomachinery Second Edition Revised - Ventech!

lighter supercharged engine can produce the same power as a larger and
heavier normally aspirated engine (Fig. 1). The smaller engine (1) consumes
less fuel under idle conditions, (2) has less mass and inertial loading, (3) has
lower frictional and partial-load pumping losses, and (4) produces less
emissions under partial-load conditions. Smaller supercharged engines in
turn allow smaller, more compact vehicles without sacrificing performance.
Supercharging can compensate for the power loss that occurs with the less
dense air available as a vehicle climbs in altitude.
A supercharger typically consists of a compressor to increase the
pressure of the air inflow, which is usually driven off the engine crankshaft
either by belts or gears (Fig. 2). A turbo supercharger, or simply a
turbocharger, consists of a centrifugal compressor that is driven directly by
a gas turbine, which in turn is driven by engine exhaust gases. It should be
noted that a turbocharger is a form of supercharger. However, common
terminology will be used here. A mechanically driven compressor will be
called a supercharger, while an exhaust-driven turbine/centrifugal compressor
combination is aturbocharger (Fig. 3).
Figure 1 Comparison of the performance between a turbo supercharged
(turbocharged) diesel V-8 engine and a naturally aspirated engine (nonsuper
charged). (Courtesy Hypermax Engineering, Inc.)
Copyright © 2003 Marcel Dekker, Inc.