5034629 JOHNSON HOLDER, ENGINE

Illustration 1 g01332437
Typical fuel system schematic
(1) Fuel supply line
(2) Unit injectors
(3) Fuel gallery (fuel manifold)
(4) Electronic Control Module (ECM)
(5) Pressure regulating valve
(6) Secondary fuel filter
(7) Fuel priming pump
(8) Distribution block
(9) Fuel temperature sensor
(10) Fuel transfer pump
(11) Pressure relief valve
(12) Check valve
(13) Fuel tank
(14) Fuel return line
(15) Fuel cooler (If equipped)
(16) Fuel return line to tank The fuel supply circuit is a conventional design for unit injector diesel engines. The system consists of the following major components that are used to deliver low pressure fuel to the unit injectors:Fuel tank - The fuel tank is used to store the fuel.Fuel priming pump - The fuel priming pump is used to evacuate the air from the fuel system. As the air is removed the system fills with fuel.Fuel filter - The fuel filter is used to remove abrasive material and contamination from the fuel system.Supply lines and return lines - Supply lines and return lines are used to deliver the fuel to the different components.The purpose of the low pressure fuel supply circuit is to supply fuel that has been filtered to the fuel injectors at a rate that is constant and a pressure that is constant. The fuel system is also utilized to cool components such as the ECM and the fuel injectors.Once the injectors receive the low pressure fuel, the fuel is pressurized again before the fuel is injected into the cylinder.The unit injector uses mechanical energy that is provided by the camshaft to achieve pressures that can be in excess of 200000 kPa (30000 psi).Control of the fuel delivery is managed by the engine's ECM. Data from several of the engine systems is collected by the ECM and processed in order to manage these aspects of fuel injection control:
Injection timing
Fuel injection timing advance
Injection duration
Engine cold mode status The mechanical electronic fuel system relies on a large amount of data from the other engine systems. The data that is collected by the ECM will be used in order to provide optimum performance