The document discusses several thermodynamic cycles including the Carnot, Otto, Diesel, and Rankine cycles. The Carnot cycle consists of four steps: two isothermal processes where heat is absorbed and rejected at different temperatures, and two adiabatic processes where the gas expands and compresses with no heat transfer. The Otto cycle uses spark ignition and has two adiabatic and two isochoric processes. The Diesel cycle approximates the combustion chamber and has one isobaric and two adiabatic processes. The Rankine cycle converts heat to work like the steam engine and has two isobaric and two adiabatic processes.

2. 1. Thermodynamics Cycle
2. Carnot Cycle
3. Otto Cycle
4. Diesel Cycle
5. Rankine Cycle

3. The process which runs from the initial state and
returns again to that initial state after the gas does
work is called cycle.

4.  In the process a - b, the gas expands in adiabatic process and
the work done by the gas is the area of plane abV2Vp its value is
negative.
In process b - c the compressed gas in isothermal process is the
area of plane bcV1V2, its value is positive.
In process c - a . The gas does not do any work because its
volume is constant.
The process c – a is an isochoric process which is done to make
the gas return to its initial state.

5. The total external work done by the gas in one cycle a – b – c – a is the
area of plane abca.
A thermodynamics cycle can occurs in a heat engine, such as otto engine,
diesel engine, and steam engine. In an Otto engine, the cycle occuring is
called Otto cycle. In a diesel engine, the cycle occurring is called diesel
cycle. While in a steam engine, the cycle occuring is called Rankine
cycle.

6. This Carnot engine is
assumed as an ideal heat
engine which works
cyclically and is reversible
between two temperatures
without any loss of energy.
This imaginary Carnot
engine consist of a cylinder
containing ideal gas and
covered with a piston that
can move alternatingly in
the cylinder.
Figure 8.16 shows the work
process of Carnot engine to
produce Carnot cycle. Entire
of process in the Carnot
cycle can be represented in
pressure (P) against volume
(V) graph as follows.

7. Based on the graph above, then the carnot cycle consist of the following
steps.
Step 1 The engine absorbs heat from the heat source or high
temperature reservoir T1 so that the ideaL gas in the engine
experiences isothermal expansion (temperature of system is equal to
temperature of reservoir). The expanded gas applies a work on the
piston, so that the gas volume are changes from v1 to v2. This
expansion is shown in Figure 8.16, with changes from state a to b along
an isothermal graph. During this isothermal gas expansion, the gas
receives heat equal to Q1.

8. Step 2 The heat source is removed so that there is no heat input to the
system. The gas still expands adiabatically and applies works to change
gas volume from V2 to V3 In this process the gas temperature decreases
to T2. This process is shown in Figure 8.16 with change of state from b
to c along an adiabatic graph.

9. Step 3. The gas experiences isothermal compression by giving away
an amount of Q2 heat the low temperature reservoir T2, In this process,
the gas volume decreases from v3 to v4. This compression is shown in
Figure 8.16, with change of state from c to d along an isothermal
graph.

10. Step 4. The gas experiences adiabatic. compression and returns to its
initial state. In this process, a work is applied on the gas so that the gas
volume decreases from V4 to V1. This compression is shown in Figure
8.l6, with change of state from d to a along an adiabatic graph.

11. Total work which done by gas in one cycle is equal to wide of area in
cycle.
Because during process of Carnot cycle the gas accept kalor Q1 from high
temperature reservoir and free a heat Q2 to low temperature reservoir.
Hence the work is done by gas according to first law of Thermodynamic is
Q = U + W atau Q1 - Q2 = 0 + W
W = Q1 − Q2

12. The Otto engine was made by Nikolaus August Otto (1832-1891),
a technician born in Holzhausen, Germany. This Otto engine is usu-
ally used in automobiles and airplanes.
An Otto cycle is an idealized thermodynamic cycle which describes
the functioning of a typical spark ignition reciprocating piston engine.
The Otto cycle is constructed out of: TOP and BOTTOM of the loop: a
pair of parallel adiabatic processes. LEFT and RIGHT sides of the loop:
a pair of parallel isochoric processes.
Otto cycle
a – b and c - d process : adiabatic process
b – c and d - a process : isochoric process

13. The Diesel engine was made by the German engineer Rudolf Chris-
tian Karl Diesel (1858-1913). The Diesel cycle is the thermodynamic
cycle which approximates the pressure and volume of the combustion
chamber of the Diesel engine.
The Diesel engine is usually used in electric generators, trucks, buses,
and several types of cars.
Diesel cycle
a - b process : isobaric process
b - c and d - a process : adiabatic process
c - d process : isochoric process

14. The Rankine engine was made by William John Macquorn Rankine, a
Scottish polymath and Glasgow University professor.
The Rankine cycle is a cycle that converts heat into work.
The Rankine cycle is the fundamental thermodynamic underpinning of
the steam engine.
The Rankine cycle is sometimes referred to as a practical Carnot cycle
because, when an efficient turbine is used, the TS diagram begins to
resemble the Carnot cycle. The main difference is that heat addition (in
the boiler) and rejection (in the condenser) are isobaric in the Rankine
cycle and isothermal in the theoretical Carnot cycle.
a - b and c - d process : isobaric process
b – c and d - a process : adiabatic process