With an increasing temperature of intake air, IC engine efficiency _______
A. decreases
B. increases
C. remains same
D. depends on other factors
Answer: Decreases.
Because the specific volume of the intake air increases w.r.t. increasing temperature.
More specific volume means more volume required for same mass of the air.
Therefore with increasing temperature, the amount of mass of intake air reduces and in turn less amount of oxygen comes into the engine cylinder.