In a compression ignition engine working on the ideal dual$-$combustion cycle, the volumetric compression ratio is $12\mathrm{.}5$:$1.$ The cycle consists of $($a$)$ adiabatic compression from $\frac{1\mathrm{.}013}{b}ar,35C,($b$)$ heat received at constant volume to a maximum pressure of $40$ bar $,($c$)$ heat received at constant pressure to a maximum temperature of $1425C,($d$)$ adiabatic expansion to the initial volume, $($e$)$ heat rejected at constant volume. Make a sketch of the pV diagram and calculate the mean effective pressure.

Take $y=1\mathrm{.}4$ for air and products of combustion

Area under an adiabatic curve $=\frac{p_1{V}_1-p_2{V}_2}{-1}$