Question

The bore and stroke of the cylinder of a 6-cylinder engine working in the Otto cycle are 15 cm and 30 cm respectively. Where total clearance volume is $6750c{m}^3$. Then compression ratio of the cycle is

• A. 6.82
• B. 5.14
• C. 6.25
• D. 5.71

Answer 1

The correct option is D 5.71

$Areaofsuction=\frac{\pi }{4}\times {15}^2\times 30$

$V_c=\frac{6750}{6}c{m}^3$

$Compressionratio=\frac{V_s+V_c}{V_c}$

$=\frac{\frac{\pi }{4}\times {15}^2\times 30+\frac{6750}{6}}{\frac{6750}{6}}$

$=\frac{(\frac{\pi }{4}+\frac{1}{6})}{\frac{1}{6}}=\frac{3\pi +2}{2}$

$=\frac{3\times 3.14+2}{2}=\frac{11.42}{2}=5.71$