BOLT-TRACK 1434891 - Caterpillar

Introduction (Fuel Injection)
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Diagram of the basic fuel system (typical example) (1) Electronic Unit Injector (2) Solenoid for the fuel injection pump (3) Wastegate Valve (if equipped) (4) Secondary Speed/Timing Sensor (5) Fuel Injection Pump (6) Primary Speed/Timing Sensor (7) Intake Manifold Pressure Sensor (8) Fuel Manifold Pressure Sensor (9) Engine Oil Pressure Sensor (10) Intake Manifold Temperature Sensor (11) Coolant Temperature Sensor (12) Diagnostic Connector (13) Electronic Control Module (ECM)Low Pressure Fuel System
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Low-pressure fuel system (typical example) (1) Primary fuel filter (2) Water separator (3) Fuel transfer pump (4) ECM that is fuel cooled. (5) Fuel cooler (optional) (6) Secondary fuel filter (7) Fuel Injection Pump (A) Outlet for high-pressure fuel to the high-pressure fuel manifold (B) Return from the Pressure Relief Valve (PRV) on the high-pressure fuel manifold (C) Return to fuel tank (D) Return from the Electronic Unit Injectors (E) Fuel in from the fuel tankFuel is drawn from the fuel tank (E) through a Primary fuel filter (1) and the water separator (2) to the Transfer pump (3) . The transfer pump increases the fuel pressure to 300 to 550 kPa (44 to 80 psi) at an engine speed of 1000 rpm. The fuel is pumped through the fuel cooler (optional) (5) to the ECM (4) . The fuel cools the ECM. The fuel passes from the ECM to a Secondary fuel filter (6) . The fuel filters remove particulates from the fuel in order to prevent contamination of the high-pressure components in the fuel system. Fuel passes from the fuel filter to the fuel injection pump (7) . The fuel is pumped at an increased pressure to the high-pressure fuel manifold. Excess fuel from the high-pressure fuel pump returns to the tank through a non-return valve. There is a small orifice in the fuel filter base in order to purge any air back to the tank.The leak off fuel from the electronic unit injectors returns from a connection in the cylinder head to the pressure side of the transfer pump.High Pressure Fuel System
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High-pressure fuel system (typical example) (1) Electronic Unit Injector (2) High Pressure Fuel Manifold (3) Fuel Pressure Sensor (4) Fuel Pressure Relief Valve (5) Fuel Transfer Pump (6) Solenoid for the Fuel Injection Pump (7) Fuel Injection PumpThe fuel injection pump (7) feeds fuel to the high-pressure fuel manifold (2) . The fuel is at a pressure of 70 MPa (10152.7 psi) to 130 MPa (18855 psi). A pressure sensor (3) in the high-pressure fuel manifold (2) monitors the fuel pressure in the high-pressure fuel manifold (2) . The ECM controls a solenoid (6) in the fuel injection pump (7) in order to maintain the actual pressure in the high-pressure fuel manifold (2) at the desired level. The high-pressure fuel is continuously available at each injector. The ECM determines the correct time for activation of the correct electronic unit injector (1) which allows fuel to be injected into the cylinder. The leakoff fuel from each injector passes into a