Consider a spark$-$ignition engine for which the compression ratio is $8\mathrm{.}6.$ Prior to the isentropic compression process, the air is at $300K$ and an unknown pressure. The pressure doubles during the heat$-$addition process. Determine

a$.$ the specific amount of heat transferred in

b$.$ the net specific work for the cycle

c$.$ the thermal efficiency of the engine

A complete solution should include a labeled diagram of each state. The gas constant $R$ for air is $0\mathrm{.}2870$kPa$*\frac{m^3}{k}g*K,$ and take the specific heat capacities to be $c_P=1\mathrm{.}005$kPa$*\frac{m^3}{k}g*K$ and $c_v=0\mathrm{.}718$kPa$*\frac{m^3}{k}g*K.$

Selected Ans: $W_{\text{n}\text{e}\text{t}}=-293\mathrm{.}7k\frac{J}{k}g,{}_{th}=57\mathrm{.}7\%$