All About Engines
Forfatter: Edward Cressy
År: 1918
Forlag: Cassell and Company, LTD
Sted: London, New York, Toronto and Melbourne
Sider: 352
UDK: 621 1
With a coloured Frontispiece, and 182 halftone Illustrations and Diagrams.
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i84 All About Engines
should be blown out of the top. This piston, more-
over, was not connected to the shaft by a connect-
ing rod and crank in the ordinary way. There was
a connecting rod, but it was provided with teeth all
the way along the upper half, forming a rack, and
the shaft was provided with a toothed wheel into
which the teeth of the rack fitted. When an ex-
plosion occurred the piston rose rapidly, and the
rack, acting on the toothed wheel, caused the shaft to
spin round. Having arrived at the top of its stroke,
the rack disengaged with the wheel, fell away from it,
and allowed the piston to return to the bottom of the
cylinder without affecting the rotating shaft. During
this return stroke the exploded gases were swept
out through the exhaust valve, and in the interval
between the strokes a heavy flywheel kept the shaft
in motion.
Crude in design, cumbrous in action, and irregular
in speed as the Lenoir engine was, a great many
were made before, in 1876, Dr. Otto invented a far
more perfect form—the parent of the gas engine of
to-day. Its mode of operation is shown diagrammatic-
ally in Fig. no. The first outward stroke of the
piston draws in a mixture of air and gas, the valves
being opened just long enough for the right pro-
portion of each to enter. As the shaft continues
to rotate the piston makes its return stroke, and as
the gas and air valves are now closed the mixture
is compressed. The efficiency of the engine increases
with the degree of compression, but it must not be
too high or the explosion will take place prema-