Answer Happy

You are considering the possibility of using butanol (C4H10O) with a lower heating value of 33.2 MJ/kg as a fuel for a four-stroke, six-cylinder, automotive spark-ignition engine. Each engine cylinder has a displaced volume of 450 cm³ and a clearance volume of 50 cm³. The engine operates unthrottled at an equivalence ratio = 0.95. The inlet mixture is at a temperature of 310 K and a pressure of 100 kPa. Assuming that the engine follows the ideal Otto cycle, the working fluid behaves as an ideal gas with constant specific heats (y=1.35), the residual fraction is 7.5%, and the universal gas constant R = 8.314 kJ/kmol-K. a) Determine the molecular weight and the air/fuel ratio of the fresh mixture. b) Determine the net indicated fuel conversion efficiency of the cycle. e) Determine the indicated power developed by the engine at 6000 rev/min. Does it look attractive for an engine of its size?