16
Small Piston Heat Engine
012-08375A
P
d
=
V
d
=
g
. We suspect that transitions from
a
➔
b
and from
c
➔
d
are approximately adiabatic. Explain why.
h
. You should have found that the transitions from
b
➔
c
and from
d
➔
a
are isobaric. Explain why this
is the case.
Finding Thermodynamic Work from the
Diagram
In the next activity, you should draw a
P- V
diagram for your cycle and determine the thermody-
namic work for your engine.
5.4 Activity: Plotting and Interpreting a
P-V Diagram
a
. Fill in the appropriate numbers on the scale on the graph frame that follows and plot the
P-V
diagram for your engine cycle. Alternatively, generate your own graph using a computer
graphing routine and affix the result in the space below.
b. On the graph in part a, label each of the points on the cycle (
a
,
b
,
c
, and
d
). Indicate on the graph
which of the transitions (
a
➔
b
,
b
➔
c
, etc.) are adiabatic and which are isobaric.