SHROUD AS 1456008 - Caterpillar

Fuel Injection Pump
The fuel injection pump increases the pressure of the fuel and the fuel injection pump sends an exact amount of fuel to the fuel injector nozzle. There is one fuel injection pump for each cylinder in the engine.
Illustration 4 g00533415
Fuel Injection Pump (1) Spill port (2) Check valve (3) Pump barrel (4) Bypass port (5) Pump plunger (6) Spring (7) Fuel rack (8) Gear (9) Lifter (10) CamThe fuel injection pump is moved by cam (10) of the fuel pump camshaft. When the camshaft turns, the cam raises lifter (9) and the pump plunger (5). The pump plunger always makes a full stroke. As the camshaft turns farther, spring (6) returns the pump plunger and the lifter to the bottom of the stroke.
Illustration 5 g00533417
Pump Barrel And Plunger Assembly (1) Spill port (2) Check valve (3) Pump barrel (4) Bypass port (5) Pump plunger (11) Orificed reverse flow check valve (12) Spring (13) Spring (14) Scroll (15) SlotWhen the pump plunger is at the bottom of the stroke, fuel at transfer pump pressure flows through spill port (1) and bypass port (4). Fuel fills pump barrel (3) in the area above pump plunger (5).
Illustration 6 g00533423
Pump Barrel And Plunger Assembly (1) Spill port (2) Check valve (3) Pump barrel (4) Bypass port (5) Pump plunger (11) Orificed reverse flow check valve (12) Spring (13) Spring (14) Scroll (15) SlotAfter the pump plunger (5) begins the up stroke, the fuel will be pushed out of the bypass port (4) until the top of the pump plunger closes the port. As the pump plunger travels further upward, the pressure of the fuel increases. At approximately 690 kPa (100 psi), the check valve (2) opens. This allows fuel to flow into the fuel injection line to the fuel injector nozzle.
Illustration 7 g00533426
Pump Barrel And Plunger Assembly (1) Spill port (2) Check valve (3) Pump barrel (4) Bypass port (5) Pump plunger (11) Orificed reverse flow check valve (12) Spring (13) Spring (14) Scroll (15) SlotWhen the pump plunger travels further upward, the scroll (14) uncovers the spill port (1). The fuel above the pump plunger goes through the slot (15). The fuel then goes along the edge of the scroll (14). The fuel then goes out of the spill port (1). The fuel then goes back to the fuel manifold. This is the end of the injection stroke. Although the pump plunger can have more travel upward, no more additional quantities of fuel will be sent to the fuel injector nozzle.
Illustration 8 g00533427
Pump Barrel And Plunger Assembly (1) Spill port (2) Check valve (3) Pump barrel (4) Bypass port (5) Pump plunger (11) Orificed reverse flow check valve (12) Spring (13) Spring (14) Scroll (15) SlotWhen spill port (1) is opened by plunger (5) the fuel injector nozzle closes and spring (13) closes check valve (2) as the pressure above plunger (5) drops below 690 kPa (100 psi). At the same time orificed reverse flow check valve (11) opens. Orificed reverse flow check valve