A Lenoir engine (described in P3.5) operates with inlet conditions of \(p_{1}=1 \mathrm{bar}\) and \(T_{1}=27^{\circ} \mathrm{C}\). The energy added to the charge is \(1000 \mathrm{~kJ} / \mathrm{kg}\), and the expansion ratio, \(r_{e}\), is 3.0. Calculate the maximum pressure and temperature achieved in the cycle and its thermal efficiency.

[5.65 bar; \(1422^{\circ} \mathrm{C} ; 26.00 \%\) ]

P3.5

The engine designed by Lenoir was essentially an atmospheric engine based on the early steam engines. In this, a combustible mixture was contained in a cylinder: it was ignited and the pressure increased isochorically to the maximum level. After this the gas expanded isentropically through an expansion ratio, \(r_{\mathrm{e}}\), during which it produced work output. The air-standard cycle returned the gas to state 1 through an isochoric expansion to \(p_{1}\) and an isobaric compression to \(V_{1}\).

Assume \(p_{1}=1\) bar, \(T_{1}=15{ }^{\circ} \mathrm{C}, p_{2}=10\) bar and the expansion ratio, \(r_{\mathrm{e}}=5\). Calculate the specific work output and thermal efficiency of this cycle. How does this compare with the efficiency of an equivalent Carnot cycle?

\([650.30 \mathrm{~kJ} / \mathrm{kg} ; 34.97 \% ; 90.0 \%]\)