GEAR-BEVEL 9C8219 - Caterpillar

Illustration 1 g00322667
Fuel flow schematic (typical example)
(1) Fuel manifolds
(2) Fuel filter
(3) Fuel priming pump
(4) Fuel injectors
(5) Pressure regulating valve
(6) Fuel return to tank
(7) Primary fuel filter
(8) Fuel transfer pump
(9) Fuel line to filter
(10) Fuel supply line from the primary fuel filter
(11) Fuel line to priming pump Fuel is pulled through primary fuel filter (7) by fuel transfer pump (8). Fuel transfer pump (8) delivers the fuel to fuel filter (2).Fuel transfer pump (8) has a check valve and a bypass valve. The check valve is located in the pump head assembly. The pump head assembly is located behind the connection for fuel line (9). The check valve prevents fuel flow back through the fuel transfer pump when fuel priming pump (3) is used.The bypass valve is located behind a cap (plug) in the drive end of the pump. The bypass valve limits the maximum pressure of the fuel. The bypass valve will open the outlet side of the pump to the pump inlet if the fuel pressure exceeds 860 kPa (125 psi). This process helps prevent damage to the fuel system components from too much pressure.
Illustration 2 g00735965
(1) Fuel manifold
(2) Fuel filter
(8) Fuel transfer pump
(9) Fuel line to filter
(10) Fuel supply line from the primary fuel filter
(11) Fuel line to priming pump
Illustration 3 g00322727
Fuel flow through injector
(4) Fuel injector
(12) Outlet fuel line
(13) Inlet fuel line
(14) Drilled passage
(15) Cylinder head
(16) Cylinder The fuel transfer pump delivers fuel through fuel filter (2). The fuel transfer pump then delivers fuel to fuel manifolds (1). The fuel flows through fuel manifold (1) to inlet fuel line (13) which is connected to the right side of each cylinder head (15). Filter screens are located in the ports of the fuel injector. Drilled passage (14) in the cylinder head delivers fuel to a circular chamber around fuel injector (4). The chamber is made by the O-rings on the outside diameter of the fuel injector and by the injector bore in the cylinder head.
Illustration 4 g00322726
Cylinder heads
(4) Fuel injector
(12) Outlet fuel line
(13) Inlet fuel line Only part of the fuel in the chamber is used for injection. Approximately three to five times the amount of fuel that is needed for normal combustion flows through the chamber. This fuel then flows to a drilled passage in the left side of the cylinder head. This passage is connected by outlet fuel line (12) to the bottom section of the fuel manifold. This constant flow of fuel around the injectors helps to cool the injectors.The fuel flows back through fuel manifolds (1). The fuel flows to pressure regulating valve (5) on the front of the right fuel manifold. The fuel flows through this valve. Fuel then flows back to the tank.Pressure regulating valve (5) consists of a spring and a plunger. This arrangement is between the bottom section of the fuel manifolds and the line that returns fuel to the tank. The valve keeps the pressure of the fuel between 415 to 450 kPa (60 to 65 psi).