In an engine operating in the Otto cycle, the final volume of the fuel-air mixture is one sixth the initial volume. Assume γ = 1.4. The maximum theoretical efficiency of this cycle is
A)17%.
B)49%.
C)51%.
D)56%.
E)83%.

Question

Quizplus · Accepted Answer

The efficiency of the Otto Cycle is given by:

η = 1 - (1/r^(γ-1))

where r is the compression ratio of the engine.

Since the final volume is one-sixth the initial volume, the compression ratio can be found as:

r = (V_1/V_6)^(1/γ-1) = 6^(1/0.4) = 15.59

Substituting this into the efficiency equation:

η = 1 - (1/15.59^(1.4-1))

η = 51%

Therefore, the maximum theoretical efficiency of this cycle is 51%, which corresponds to choice C.

In an Engine Operating in the Otto Cycle, the Final