Question 198Motor Plants - Assistant Engineer

70% to pass

A two-stroke cycle diesel engine requires less starting air than a four-stroke cycle diesel engine, of equal displacement, because the two-stroke cycle diesel engine _______________.

Ahas little or no internal friction

Bhas a lower effective compression ratio

Coperates with scavenge air under a positive pressure

Doperates without energy absorbing intake and exhaust strokes

AI Explanation

The correct answer is D) operates without energy absorbing intake and exhaust strokes. In a two-stroke cycle diesel engine, the intake and exhaust strokes are combined into a single stroke, which means the engine does not have the energy-absorbing intake and exhaust strokes that a four-stroke cycle diesel engine has. This allows the two-stroke cycle diesel engine to require less starting air compared to a four-stroke cycle diesel engine of equal displacement. The other answer choices are incorrect because they do not directly explain the reduced starting air requirement of a two-stroke cycle diesel engine. A two-stroke cycle engine does not necessarily have less internal friction (A), and the effective compression ratio may not be lower (B). The positive pressure scavenge air (C) is a characteristic of two-stroke engines, but it is not the primary reason for the reduced starting air requirement.