Engine operation with iso-octane and the mixed (H + C8H18) fuel is compared in a particular engine at a part-load condition (brake-mean effective pressure of 275 kPa and 1400 rev/min). You are given the following information about the engine operation: Fuel Equivalence ratio Gross indicated fuel conversion efficiency Mechanical rubbing friction mep Inlet manifold pressure Pumping mep nm CBH18 0.8 0.35 bmep imep, 138 kPa 46 kPa 55 kPa H + C8H18 0.5 0.4 138 kPa Estimate approximately the inlet manifold pressure with (H + C8H18) fuel. Explain your method and assumptions clearly. Note that the mechanical efficiency nm is defined as bmep bmep+rfmep + pmep ? ?