Question

The swept volume of a diesel engine working on dual cycle is 0.0053 m³ and clearance volume is 0.00035 m³. The maximum pressure is 65 bar. Fuel injection ends at 5 per cent of the stroke. The temperature and pressure at the start of the compression are 80°C and 0.9 bar. Determine the air standard efficiency of the cycle. Take γ for air = 1.4.

Answer 1

 

Swept volume, V_s = 0.0053 m³ 

Clearance volume, V_c = V₃ = V₂ = 0.00035 m³ 

Maximum pressure, p₃ = p₄ = 65 bar 

Initial temperature, T₁ = 80 + 273 = 353 K 

Initial pressure, p₁ = 0.9 bar

η_dual = ? 

The efficiency of a dual combustion cycle is given by

Compression ratio,

Also during the compression operation 1-2,

Pressure or explosion ratio

β = \(\cfrac{p_3}{p_2}\) = \(\cfrac{65}{44.22}\) = 1.47

Putting the value of r, ρ and β in eqn. (i), we get