Coast Guard Exams
Question 50Motor Plants - Assistant Engineer70% to pass

Injection pressure in a common rail fuel system is controlled by _______________.

AI Explanation
The correct answer is D) a bypass valve. In a common rail fuel system, the injection pressure is controlled by a bypass valve. This valve regulates the pressure in the common rail by allowing excess fuel to bypass the high-pressure fuel pump, thereby maintaining the desired injection pressure. This is done independently of engine speed (option A) or the fuel pump piston stroke (option B). The injector needle valve clearance (option C) determines the amount of fuel injected, but does not directly control the injection pressure.