IC Engine Practice Test: Air Standard Cycles and their Analysis — Flashcards

Air Standard Cycles and their Analysis topics include: Air standard cycles, carnot and stirling cycles, otto and dual cycles, diesel cycles and comparison of otto, diesel and dual cycles.

Air standard cycles are a concept used to analyze heat engines. 
They are idealized cycles based on the following assumptions:
The working fluid is only air
Air acts as an ideal gas
Combustion processes are replaced by well-defined heat addition processes
The exhaust process is replaced by a heat rejection
All processes in the cycle are reversible
Heat is supplied from a constant high-temperature source and not from chemical reactions during the cycle 

Air standard cycles are used to simplify the analysis of internal combustion (I.C.) engines. In these cycles, a certain mass of air operates in a complete thermodynamic cycle. Heat is added and rejected with external heat reservoirs, and all the processes in the cycle are reversible. 
The air standard Otto cycle is modeled as a closed system with a fixed air/fuel mass. 
It uses the following process assumptions:
1-2 Compression which is reversible and adiabatic
2-3 Heat addition from fuel
3-4 Expansion which is reversible and adiabatic 

Air standard cycle analysis does not consider the effect of Fuel-Air ratio.