pataky@umcp-cs.UUCP (Bill Pataky) (01/28/86)
The following (kind of long) passage was reprinted without permission from
"Auto Mechanics Fundamentals" by Stockel & Stockel, 1978 Goodheart-Willcox
Co. It has just about everything you want to know about turbochargers/super-
chargers (minus the diagrams, charts and figures).
Page 155:
"SUPERCHARGERS
Superchargers are used to increase engine horsepower by forcing more air-
fuel mixture into the cylinders. The normal engine depends upon the vacuum
created by the pistons to draw the mixture into the cylinders. The super-
charger, or as it is sometimes called, 'blower', assists the vacuum by
raising the pressure of the incoming air. It does this with one of three
types of superchargers.
Superchargers can be mounted between the carburetor and manifold or
ahead of the carburetor. Due to the increase of air-fuel mixture delivered
to the engine (with a resultant increase in power), it is essential that
the engine compression and design lend itself to supercharging.
ROOTES TYPE SUPERCHARGER
In a Rootes supercharger, a pair of rotors whirling within an enclosure
seize air and carry it around and out the opposite side. This type runs about
one and a half times faster than the engine. It is a positive displacement
type. Fig 6-98.
VANE TYPE SUPERCHARGER
The vane type superchager is also a positive displacement type and works
like a vane oil pump. Its operational speed is comparable to that of the
Rootes type. Fig. 6-99.
CENTRIFUGAL TYPE SUPERCHARGER
The centrifugal supercharger is a nonpositive type. It has an impeller
with series of curved fins or vanes. As impeller is whirled, air is drawn in
at center and thrown off the rim. Air is trapped in circular housing which is
small at one end and gets progressively larger. See fig 6-100. A supercharger
driven by the engine exhaust, called 'TURBOCHARGER,' is shown in Fig. 6-92.
The turbocharger is being used on a number of engines. The additional
'boost' (air being forced into the cylinders by raising the pressure of the
column of air-fuel mix in the intakd manifold) provides increased horsepower,
torque and efficiency. Fig 6-101 shows a cutaway view of a typical turbo-
charger. Note how the turbine drives the compressor via a shaft connecting
the two. Turbochargers spin very fast - up to 120,000 rpm."
Sorry I can't include the figures to make this more complete. BTW all the
articles missing from the above passage are also missing from the book.
(I'm not that bad a typist 8-)
Bill Pataky
Laboratory for Parallel Computation
Computer Science Department
University of Maryland
ARPA: pataky@mimsy.umd.edu
UUCP: {seismo,allegra}!umcp-cs!pataky
CSnet: pataky@umcp-cs