PLATE AS 2035544 - Caterpillar

Engine Design
Cylinder And Valve Location Fuel System
General
FUEL FLOW SCHEMATIC (3512 Illustrated)
1. Fuel manifolds. 2. Fuel priming pump. 3. Pressure regulating valve. 4. Fuel injectors. 5. Fuel filters. 6. Fuel transfer pump. 7. Fuel return to supply.Fuel transfer pump (6) is located on the right side of the engine. The lower shaft of engine oil pump (12) drives the gear type transfer pump. Fuel from the supply tank goes in the transfer pump at elbow (8).The transfer pump has a check valve and a bypass valve. The check valve is located in the pump head assembly behind where line (10) is connected. The check valve prevents fuel flow back through the transfer pump when fuel priming pump (2) is used. The bypass valve is located behind cap (11). The bypass valve limits the maximum pressure of the fuel. It will open the outlet side of the pump to the pump inlet if the fuel pressure goes up to 860 kPa (125 psi). This helps prevent damage to fuel system components caused by too much pressure.The transfer pump pushes fuel through fuel filters (5) to fuel manifolds (1). The fuel manifolds have two sections. The fuel flows through the top section of the manifold to tubes connected to the right side of each cylinder head. On earlier engines, filter screens are located in the fittings where fuel goes into each cylinder head. On later engines, the filter screens are located in the ports of the unit injector. A drilled passage (15) in cylinder head (16) takes fuel to a circular (shape of a circle) chamber around the injector. The chamber is made by O-rings on the outside diameter of fuel injector (4) and the injector bore in the cylinder head.
RIGHT SIDE OF ENGINE
6. Fuel transfer pump. 8. Elbow (fuel supply). 9. Fuel line to priming pump. 10. Fuel line to fuel filter base. 11. Cap (plug) for bypass valve. 12. Engine oil pump.
FUEL FLOW THROUGH INJECTOR
4. Injector. 13. Outlet fuel line. 14. Inlet fuel line. 15. Drilled passage. 16. Cylinder head. 17. Cylinder.Only part of the fuel in the chamber is used for injection. Approximately 4 1/2 times as much fuel as needed for normal combustion flows through the chamber to a drilled passage in the left side of the cylinder head. This passage is connected by outlet fuel line (13) to the bottom section of the fuel manifold. This constant flow of fuel around the injectors helps to cool them.
CYLINDER HEADS
4. Fuel injector. 13. Outlet fuel line. 14. Inlet fuel line.The fuel flows back through the bottom section of each fuel manifold to pressure regulating valve (3), on the front of the right fuel manifold. The fuel flows through this valve and then back to the tank.Check each engine installation for an excess fuel flow based on fuel consumed (used for combustion). Minimum flow is three times the amount of fuel consumed. Excess fuel is then returned to the fuel tank, not back to the pump inlet. This