The bore and stroke of the cylinder of a six cylinder engine working on an Otto cycle are 17 cm and 30 cm respectively, total clearance volume is 9225

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The bore and stroke of the cylinder of a six cylinder engine working on an Otto cycle are 17 cm and 30 cm respectively, total clearance volume is 9225 cm3, and then what is the compression ratio?
1. 7.8
2. 6.2
3. 15.8
4. 5.4

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Correct Answer - Option 4 : 5.4

Concept:

The compression ratio in otto cycle can be given as,

${\bf{r}} = \frac{{{V_c} + {V_s}}}{{{V_c}}}$

where, r = compression ratio, Vc = Clearance volume, Vs = Swept volume

Calculation:

Given:

D = 17 cm, L = 30 cm, n = Number of cylinder = 6, Vc = 9225 cm

${V_s} = \frac{\pi }{4}{D^2} \times L \times n = \frac{\pi }{4}\times{17^2} \times 30 \times 6 = 40856.41\;c{m^2}$

${\rm{r}} = \frac{{{V_c} + {V_s}}}{{{V_c}}} = \frac{{9225 + 40856.41}}{{9225}} = 5.42$

∴ The compression ratio is 5.41.