Question

The volumetric efficiency of an air-cooled engine is higher due to high cylinder head temperatures.

(a) True

(b) False

I have been asked this question in semester exam.

My doubt stems from Air Cooled Systems in chapter Heat Rejection and Cooling of IC Engine

Answer 1

The correct answer is:

(b) False

The volumetric efficiency of an air-cooled engine is not necessarily higher due to high cylinder head temperatures. In fact, high cylinder head temperatures can have a negative effect on volumetric efficiency. As the temperature increases, the air intake charge can expand, reducing its density. Lower-density air means less oxygen is available for combustion, which decreases the engine's volumetric efficiency.

While air-cooled engines have their own unique cooling dynamics, excessively high cylinder temperatures can limit the engine's overall efficiency, including its volumetric efficiency.