SHROUD AS 1662095 - Caterpillar

Illustration 1 g00282481
Typical Example of a 3508B EngineFuel System SchematicThe fuel supply is a design that is conventional for engines that use fuel injectors. The fuel supply circuit uses a fuel transfer pump to deliver fuel from the fuel tank to the electronic fuel injectors. The transfer pump is a fixed displacement gear pump.The fuel flows from the fuel transfer pump through the cored passages of the electronic control module (ECM). This cools the module. Then, the fuel flows through a fuel filter before the fuel enters the fuel supply manifold. A fuel priming pump is located on the fuel filter base in order to fill the system. The system will be refilled after the filter changes. The system will be refilled after the fuel supply manifold and the return manifold are drained. The system will also be refilled when the fuel injectors are replaced.The fuel flows continuously from the fuel supply manifold through the fuel injectors. The fuel flows when either the supply or the fill port in the injector is not closed by the injector body assembly plunger. The fuel is returned to the tank by the fuel return manifold. The fuel that is not injected into the cylinder is displaced by the plunger and the fuel is returned to the tank through the fuel return manifold.A pressure regulating valve is at the end of the fuel return manifold. The pressure regulating valve controls the entire fuel system pressure. This provides proper filling of the fuel injectors.