Question

Problem 1 (100 pts): You are investigating the performance of a spark-ignition engine to be operated with a new gasoline fuel blend with a substantially higher auto-ignition temperature than traditional fuel, which allows for compression ratios up to 20. In this first-cut analysis, you are required to estimate the efficiency of the SI cycle for compression ratios between 5 and 20 based on the ideal Otto cycle, with one exception: you need to account for frictional loss during the compression and expansion parts of the cycle, which can still be assumed to be adiabatic. Previous data has shown that the frictional loss can be expressed as a fraction of the work input (during compression) or output (during expansion) Wioss-fWotto where fcan be expressed as a function of the compression ratio as: 36 In your analysis, use minimum and maximum cycle temperatures of 300 K and 1800 K, respectively Show the SI cycle and the corresponding ideal Otto cycle (working with the same compression ratio and temperature limits) on the same T-s diagram. (10 pts) a)

Answer 1

Soluhon grtiun egne ven ,2, 3, uaima 1 14, 3-9ラ2deal

어 V2. CO 3 う foY ideal tises. 1 →e and 374 pocess ase alphabetic Vy

3 fo 3-witten 극.er-, C) 13 Y-1 (16O Abuo

eguaton :36

2 9-.57 cyc le