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A vehicle powered by a spark ignition engine follows air standard Otto cycle (γ = 1.4). The engine generates 70 kW while consuming 10.3 kg/hr of fuel. The calorific value of fuel is 44000 kJ/kg. The compression ratio is (correct to two decimal places).
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- γ = 8
- γ = 8.61
- γ = 7.61
- γ = 9
Correct Option: C
r = 14
BP = 70 kW
Ṁf = 10.3 kg/hr
C.V. = 44000 kJ/kg
| η = | = | ||
| Ṁf × C.V. | 10.3/3600 × 44000 |
η = 0.556
| ηotto = 1 - | = 0.556 | |
| (r)γ-1 |
⇒ γ = 7.61
