72. Which one of the following event would reduce volumetric efficiency of a vertical compression ignition engine ?

inlet valve closing after bottom dead centre
inlet valve closing before bottom dead centre
inlet valve opening before top dead centre
exhaust valve closing
✅ The correct answer is option B.

75. In a four stroke cycle diesel engine, the exhaust valve

opens at 30° before bottom dead cnetre and closes at 10° after top dead centre
opens at 30° after bottom dead centre and closes at 10° before top dead centre
opens at bottom dead centre and closes at top dead centre
may open and close any
✅ The correct answer is option A.

79. The brake power (B.P.) of the engine is given by (where W = Brake load or dead load in newtons, l = Length of arm in metres, N = Speed of engine in r.p.m., S – Spring balance reading in newtons, D = Dia. of brake drum in metres, and d = Dia. of rope in metres)

all of these
✅ The correct answer is option D.