Question

High speed two stroke engines are ____________ efficient owing to the reduced volumetric efficiency.

(a) high

(b) less

(c) equal

(d) none of the mentioned

This question was posed to me in an online quiz.

Origin of the question is Disadvantages of Two Stroke Engines topic in chapter Two Stroke Engines of IC Engine

Answer 1

Answer: (b) less

Explanation: High-speed two-stroke engines tend to have lower efficiency compared to their low-speed counterparts. This is due to reduced volumetric efficiency, which results from the incomplete scavenging process. At high speeds, there is less time for the exhaust gases to be fully expelled and for the fresh charge to fill the cylinder. This inefficiency leads to a loss in power and fuel economy, making high-speed two-stroke engines less efficient overall.