When fuel exits a gear pump discharge port while an engine is run, what force moves more fuel into the gear pump inlet in a typical diesel fuel subsystem?

Question

Quizplus · Accepted Answer

Atmospheric pressure pushes more fuel into the gear pump inlet as fuel exits the discharge port. This is because the fuel system is designed to maintain a certain level of vacuum or low pressure at the pump inlet, encouraging atmospheric pressure to push fuel from the tank into the pump.

When Fuel Exits a Gear Pump Discharge Port While an Engine