Question

An ideal diesel cycle has bore equal to 10 cm and stroke equal to 20 cm. The clearance volume is 10 percent at stroke and cut-off takes place at 5 percent of stroke. Determine the compression ratio and cut-off ratio respectively

• A. 11 and 1.5
• B. 1.5 and 11
• C. 15 and 1.1
• D. 1.1 and 15

Answer 1

The correct option is A 11 and 1.5


$\text{r= compression ratio}$

$=\frac{v_1}{v_2}=\frac{v_2+v_s}{v_2}$

$r=1+\frac{v_s}{v_2}=1+\frac{v_s}{0.1v_s}$

$\Rightarrow r=1+10=11$

$\Rightarrow \frac{v_3}{v_2}=\text{cut-off ratio}=\frac{01.v_s+0.15}{0.1v_s}=\frac{0.15}{0.1}=1.5$