What type of pump can vary the amount of fuel discharged regardless of speed?

A variable displacement pump is designed to adjust the amount of fluid it discharges based on the requirements of the system, independent of the pump’s speed. This means that it can increase or decrease fuel delivery as needed, which is crucial in applications where precise fuel flow is necessary, such as in aircraft engines.

In contrast, constant displacement pumps deliver a fixed volume of fluid per cycle, regardless of the speed at which they operate, thus lacking the flexibility needed for varying fuel demands. Positive displacement pumps, while capable of moving fluid efficiently, do not inherently adjust their output without additional mechanisms or controls, which limits their adaptability for varying demands. Reciprocating pumps, similar to positive displacement pumps, also move a specific volume with each stroke and do not inherently vary output based on conditions unless modified or controlled externally.

Therefore, the ability of a variable displacement pump to modulate fuel flow on demand makes it the ideal choice in scenarios where fuel requirements fluctuate.