PASCO TD-8565 Adiabatic Gas Law Apparatus - Manual (Page 17)

Experiment 4: Complete Cycle
© 2009 Physics Enterprises 17
The efficiency of any heat engine is defined as,
(4.1)
This is equivalent to the net area under a P vs. V curve and divided by the heat entering the
system. For the Otto cycle, the work is area between the two adiabatic strokes and heat
enters the system during the isovolumetric combustion stroke.
In this experiment, you will be operating the Otto Cycle in reverse.
In Heat
Out Work
= η
Reversed Otto Cycle
P-V diagram
P
V
The procedure begins with an adiabatic compression. The area under the upper-most curve
is the work done on the gas, W
on
. The gas is then cooled to the original temperature
isovolumetrically, such that Q
out
= W
on
. An adiabatic expansion is then followed by
isovolumetric heating with Q
in
= W
by
.