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A diesel engine has a compression ratio of 17 and cut-off takes place at 10% of the stroke. Assuming ratio of specific heats (γ) and the air standard efficiency (in%) is –.
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- 59.60%
- 56%
- 59%
- 60%
Correct Option: A
Compression ratio
| = 17 = | = V1 = 17V2 | V2 |
where ρ = cut-off ratio
| = | V2 |
| V3 - V2= | Vs | 100 |
V3 – V2 = 0.1(V1 – V2)
= 0.1(17V2 – V2)
= 0.1(16V2)
V3 = 1.6V2 + V2
V3 = 2.6V2
| = | = ρ = 2.6 | V2 |
| η = 1 - | × |  |  | ||||
| γ(r)γ - 1 | ρ - 1 |
| = 1 - | × | | | |||
| 1.4(17)1.4 - 1 | 2.6 - 1 |
= 0.5960 = 59.60%.
