Subtopic: Thermodynamic principles of I.C. engines
Question Statement:
In the second-law availability (exergy) analysis of an internal combustion engine, the single largest cause of exergy destruction (irreversibility) inside the engine is:
Options:
(A) Uncontrolled chemical reaction during combustion across extreme temperature gradients
(B) Viscous mechanical friction between piston rings and the cylinder liner
(C) Thermal conduction through the exhaust valve stem
(D) Pressure throttling across the intake air cleaner
Answer Key:
A
Step-by-Step Solution & Explanation
Second-law exergy analysis demonstrates that uncontrolled chemical combustion across steep temperature and concentration gradients accounts for 20% to 25% of total fuel exergy destruction, far surpassing mechanical friction or fluid throttling losses.