SUPERCHARGER

Q$4.$ A four$-$stroke CI engine has a capacity of $2\mathrm{.}8$ litres running at $3000$ RPM$.$ The average indicated power developed is $12\mathrm{.}5$ kW per m $3$ of free air inducted per. The volumetric efficiency of $85\%$ referred to free air conditions of $1\mathrm{.}013$ bar and $15$ degC. A blower driven mechanically from the engine is used as a supercharger. It has an isentropic efficiency of $74\%$ and works through a pressure ratio of $1\mathrm{.}6.$ Assume that at the end of induction the cylinders contain a volume of charge equal to the swept volume at the pressure and temperature of the delivery from the blower.

Lecture Notes by Dr Ali Sarosh: Internal Combustion Engine

Calculate the volumetric efficiency of supercharged engine, the increase in brake power by supercharging and express this increase in percentage. Assume all mechanical efficiencies to be $78\%.$

$($Ans: increase in brake power $=23\mathrm{.}4kW,$ power required by blower $=8\mathrm{.}283$kWdotsdots.