The document compares the Carnot cycle and Otto cycle. The Carnot cycle consists of four processes - two reversible adiabatic expansions and two reversible isothermal compressions. It has the highest possible efficiency. The Otto cycle models the four-stroke internal combustion engine. It consists of intake, compression, power, and exhaust strokes. Like the Carnot cycle, it converts heat into work but is less efficient. Both cycles are important in modeling heat engines.

1. Comparison Between
CARNOT CYCLE AND
OTTO CYLCE
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2. CARNOT CYCLE
• Devised by Nicolas Leonard Sadi Carnot (1796-
1832)
• The Carnot cycle, is thermodynamic process
that describes, how fluid is used to convert
thermal energy to work
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3. The Carnot cycle consists of the
following four processes:
1. A reversible isothermal gas expansion
process.
2. A reversible adiabatic gas expansion process.
3. A reversible isothermal gas compression
process
4. A reversible adiabatic gas compression
process.
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4. The P-V diagram of the Carnot cycle
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5. T-S Diagram
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6. Efficiency
• The Carnot cycle is the most efficient engine possible
based on the assumption of the absence of
incidental wasteful processes such as friction, and
the assumption of no conduction of heat between
different parts of the engine at different
temperatures. The efficiency of the Carnot engine is
defined as the ratio of the energy output to the
energy input.
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7. Internal Combustion Engine – OTTO
Cycle
• Nikolaus Otto (1832–1891, German) who is
credited as the first creator of a petroleum
fuel based internal combustion
engine operating under a four stroke cycle.
• The Otto Cycle, describes how heat
engines turn gasoline into motion
• Like other thermodynamic cycles, this cycle
turns chemical energy into thermal
energy and then into motion
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8. The four-stroke Otto cycle is made up of the
following four internally reversible processes
• 1–2, isentropic compression
• 2–3, constant-volume heat addition
• 3–4, isentropic expansion
• and 4–1, constant-volume heat rejection.
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9. PV - Diagram
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10. Thermal efficiency
• In general, the thermal efficiency, ηth, of any
heat engine is defined as the ratio of
the work it does, W, to the heat input at the
high temperature, QH.
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11. APPLICATIONS
• The Otto Cycle provides the energy for most
transportation and was essential for the
modern world. Specifically, the vast majority
of automobiles seen on the road today use
the Otto Cycle to convert gasoline into
motion.
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