Concept:
The fuel injection pump is an important part of a diesel engine fuel system.
Step 1: In a diesel engine, fuel must be injected into the combustion chamber at high pressure.
Step 2: The fuel injection pump supplies fuel to each injector according to the firing order.
Step 3: It also develops the high pressure needed for proper atomization of diesel fuel.
Step 4: Proper atomization helps fuel mix with compressed hot air and burn efficiently.
Step 5: The pressure created by the fuel injection pump commonly varies from:
\[
120\text{ to }300\,kg/cm^2
\]
\[
\boxed{120\text{ to }300\,kg/cm^2}
\]