Coast Guard Exams
Question 96Motor Plants - Assistant Engineer70% to pass

For a given fuel, a change in the compression ratio will affect the ignition lag by which of the listed means?

AI Explanation
The correct answer is B) An increase in compression ratio will decrease the ignition lag. Increasing the compression ratio in an engine causes the air-fuel mixture to be compressed to a higher pressure and temperature before ignition. This higher temperature and pressure reduces the time it takes for the air-fuel mixture to spontaneously ignite, which is known as the ignition lag. Therefore, an increase in compression ratio will decrease the ignition lag. The other options are incorrect because: A) Increasing the compression ratio decreases the ignition lag, not increases it. C) Decreasing the compression ratio would increase the ignition lag, not decrease it. D) A change in ignition lag does not directly affect the compression ratio.