Question 95Motor Plants - 1st Asst/Chief

The correct answer is B) turbulence of the air charge. The rate of pressure rise during the period following fuel ignition in a diesel engine is influenced by the length of the ignition delay period and the turbulence of the air charge. The turbulence of the air charge affects the air-fuel mixing, which in turn influences the rate of pressure rise. More turbulent air charge leads to better air-fuel mixing and a faster rate of pressure rise. The other options are incorrect because: A) Volumetric efficiency is related to the engine's ability to draw in air, not the pressure rise after ignition. C) Fuel efficiency is a measure of fuel consumption, not the pressure rise dynamics. D) Valve overlap is a design parameter that affects the engine's breathing, not the pressure rise after ignition.