Thermo-Economic Analysis of Otto Cycle

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Thermo-Economic Analysis of Otto Cycle

• P M V Subbarao
• Professor
• Mechanical Engineering Department

Compact Efficient Description forStructure of
an Engine
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Simplified Thermodynamic Cycles

• Air-standard analysis is used to perform
  elementary analyses of IC engine cycles.
• Simplifications to the real cycle include
• 1) Intake and exhaust processes not considered
• 2) Fixed amount of air (ideal gas) for working
  fluid
• 3) Combustion process not considered
• 4) Engine friction and heat losses not
  considered
• 5) Specific heats independent of temperature

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Ottos Model for Engine cycle
Process 1? 2 Isentropic compression Process 2
? 3 Constant volume heat addition Process 3 ? 4
Isentropic expansion Process 4 ? 1 Constant
volume heat rejection
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First Law Analysis of Otto Cycle
1?2 Isentropic Compression



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First Law Analysis of Otto Cycle
2?3 Constant Volume Heat Addition



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3 ? 4 Isentropic Expansion





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4 ? 1 Constant Volume Heat Removal
Qout

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First Law Analysis of Cycle
Net cycle work
Cycle thermal efficiency
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Clue to Achieve Higher Efficiency