Question

An engine 200 mm bore and 300 mm stroke works on Otto cycle. The clearance volume is 0.0016 m3. The initial pressure and temperature are 1 bar and 60°C. If the maximum pressure is limited to 24 bar, find : (i) The air-standard efficiency of the cycle (ii) The mean effective pressure for the cycle. Assume ideal conditions

Answer 1

i.

$η=1-\frac{1}{r^{\gamma-1}} = 1-\frac{1}{8.85^{1.4-1}}=0.5879\\ \implies η= 58.19 \%$

ii.

$pm= \frac{P_1 r[r^{\gamma-1}-1]*[r_p-1]}{(r-1)(\gamma-1)}\\ pm= \frac{8.85[8.85^{1.4-1}-1]*[0.134]}{(0.4)(7.85)}\\ pm=0.526$