Which component drives the pumps in a multiple plunger in-line fuel injection system?

In a multiple plunger in-line fuel injection system, the internal camshaft is the component that drives the pumps. The camshaft converts rotational motion from the engine's crankshaft into linear motion needed to operate the plungers within the injection pump. This linear motion is essential for the precise timing and delivery of fuel into the engine’s combustion chamber.

The plungers are pushed upward by the camshaft, which allows fuel to be drawn in from the supply and then forced out at high pressure into the fuel rail or directly into the combustion chambers. This mechanism ensures that the fuel is injected at the right moment and in the right quantity, which is critical for efficient engine performance.

In contrast, while electric motors, external pumps, and fuel pressure regulators are all important components of a fuel delivery system, they do not drive the plungers in this particular context. Electric motors are used for various applications in engines but are not directly responsible for plunger operation in an in-line injection system, and external pumps typically function to pressurize fuel before it reaches the injector system rather than driving the injectors themselves. Fuel pressure regulators control the pressure within the fuel system but do not play a role in the mechanical actuation of the fuel injection plungers.