UNGRADED: One type of a multistep process is a cycle. Consider the
idealized car engine cycle, called Otto cycle. Assume that in state
1, the air-fuel mixture has been taken in and is still at 100 kPa
and 27C ambient conditions. Then the air is compressed until
state 2, where the volume is one tenth of the intake volume. Assume
that this compression stroke is polytropic with . Then from
state 2 to state 3, an isochoric 2,500C increase in temperature
takes place. Finally, from state 3 to state 4, the power stroke,
the air expands polytropically with until the volume returns
to the original intake volume value. Finally, for the process from
4 back to 1, a true car engine would dump the hot air to the exhaust
and take in fresh cool air. However, the Otto cycle assumes that
the air at step 4 is isochorically cooled down from 4 to 1 to
the original intake temperature.
Model the air-fuel mixture as pure air. Find the pressure, specific
volume, and temperature at each of the 4 stages of the cycle. Then
find the net specific work produced in the complete cycle.
Also show the cycle and the work graphically in a very neat
diagram.