Answer:
Under cold air standard conditions, the thermal efficiency of this cycle is 56.9 percent.
Explanation:
From Thermodynamics we remember that thermal efficiency of the ideal Otto cycle ([tex]\eta_{th}[/tex]), dimensionless, is defined by the following formula:
[tex]\eta_{th} = 1-\frac{1}{r^{\gamma-1}}[/tex] (Eq. 1)
Where:
[tex]r[/tex] - Compression ratio, dimensionless.
[tex]\gamma[/tex] - Specific heat ratio, dimensionless.
Please notice that specific heat ratio under cold air standard conditions is [tex]\gamma = 1.4[/tex].
If we know that [tex]r = 8.2[/tex] and [tex]\gamma = 1.4[/tex], then thermal efficiency of the ideal Otto cycle is:
[tex]\eta_{th} = 1-\frac{1}{8.2^{1.4-1}}[/tex]
[tex]\eta_{th} = 0.569[/tex]
Under cold air standard conditions, the thermal efficiency of this cycle is 56.9 percent.
