Question 96Motor Plants - Assistant Engineer

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.