The operation of a diesel engine can be idealized by

Chapter 20, Problem 20.7

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The operation of a diesel engine can be idealized by thecycle shown in Fig. 20-18. Air is drawn into the cylinderduring the intake stroke (not part of the idealized cycle).The air is compressed adiabatically, path ab. At point bdiesel fuel is injected into the cylinder which immediatelyburns since the temperature is very high. Combustion isslow, and during the first part of the power stroke, the gasexpands at (nearly) constant pressure, path be. Afterburning, the rest of the power stroke is adiabatic, path cd.Path da corresponds to the exhaust stroke, (a) Show that,for a quasistatic reversible engine undergoing this cycleusing an ideal gas, the ideal efficiency is= 1 ( v ^ r 7 - (tyyb)~Ty iiv jv c ) -1 - (ya/yb)-1] where VJVb is the compression ratio, VJVC is the expansionratio, and T is defined by Eq. 19-14.(b) If V jV h = 16 and VJVC = 4.5,calculate the efficiency assumingthe gas is diatomic (like N2 and0 2) and ideal.FIGURE 20-18 7.