MANIFOLD GP-RL 4863471 - Caterpillar

Fuel Temperature Sensor
The fuel temperature sensor is mounted on the fuel intake side and detects the temperature of the fuel using the characteristic of the thermistor, whose electrical conductivity varies with temperature.Note that the fuel temperature sensor is not treated as a part, so replacing the sensor requires replacement of the supply pump.Fuel Rail
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(39) Pressure limiter (40) Fuel rail (41) Fuel rail pressure sensorThe rail stores fuel at the high pressure applied by the supply pump and supplies the shared pressure to the injectors of each cylinder. The rail incorporates a rail pressure sensor and a pressure limiter.The pressure of the fuel in the rail is detected by the rail pressure sensor, and optimal feedback control is provided for the engine RPM and load. This greatly improves the ability to raise the pressure at low RPMs and enables high-pressure injection from low speed ranges.Pressure Limiter
The pressure limiter operates when the pressure inside the rail becomes excessively high (valve opens), and then once the pressure drops to a certain pressure, the limiter acts to maintain the pressure (valve closes).Fuel discharged by the pressure limiter returns to the fuel tank.Fuel Rail Pressure Sensor
The rail pressure sensor is mounted on the rail, detects the pressure inside the rail and sends a signal to the engine ECM.This sensor is a semi-conductor type of pressure sensor in which increasing the pressure on the silicon element changes the electrical resistance. Note that the rail pressure sensor is not treated as a part, so replacement requires replacing the rail assembly.Fuel Injector
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(42) Engine ECM (43) Rail Pressure Sensor (44) Rail (45) Supply Pump (46) Two-way Valve (47) Discharge Orifice (48) Control Chamber (49) Command Piston (50) Needle Valve (51) NozzleThe injectors inject high-pressure fuel from the rail into the combustion chamber of the engine, using signals from the engine ECM to produce the ideal timing, amount of fuel, mixture, and spray.The injector injects a finely tuned spray in three pulses during the combustion stage. First a small amount is injected, mitigating the effect of the initial burn and reducing NOx (oxides of nitrogen) and noise. The main injection follows with the real burn, and in the last stage, a diffuse combustion is induced, thus reducing particulate matter generated by the main injection.Injectors consist of nozzle components (nozzle) and needle valve), a two-way valve, which controls the volume and mixture of fuel, a control chamber with an intake orifice and discharge orifice, a command piston and a nozzle spring.Injector Operation
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(A) Injection Stop (B) Injection Start (C) Injection Finish (D) From Rail (E) To Fuel Tank (52) Solenoid (53) Two-way Valve (54) Discharge Orifice (55) Command Piston (56) Needle Valve (57) Leak Passage (58) Intake Orifice (59) Control ChamberThe injector uses the signal output from the engine ECM to control the injection with the fuel pressure in the control chamber.The system for controlling the pressure of the control chamber works by energizing the solenoid, which opens the passage of the chamber discharge orifice and the