Question 36Motor Plants - Assistant Engineer

The correct answer is B) the ratio between the cylinder volumes at top dead center and at bottom dead center. The compression ratio of a diesel engine refers to the ratio between the volume of the cylinder when the piston is at the bottom dead center (maximum cylinder volume) and the volume of the cylinder when the piston is at the top dead center (minimum cylinder volume). This ratio determines the degree of compression the air-fuel mixture undergoes before ignition, which is a key factor in the efficiency and performance of a diesel engine. The other answer choices are incorrect because they do not accurately describe the definition of compression ratio. Option A refers to the piston and connecting rod geometry, option C refers to the cylinder and piston sizing, and option D refers to the number of compression strokes, which are not directly related to the compression ratio.