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Tất cả tài liệu về bơm ECD-V (tài liệu đào tạo của Denso ECD): -Composition and Construction of ECD-V3 Pump System -Determining the Injection Timing -ECD-V Series -ECD-V4 Outline -ntake Restriction Control -Outline of Injection Ti
9SERVICE TECH Vol.465 03-4 This session describes the construction and operation of the ECD-V3 pump with respect to the pumping and injection of fuel.• Solenoid Spill Valve (SPV) - - - - - - - - - - - - - - This actuator, which performs the function of the spill ring of theprevious distributor type pump, controls the injection quantity.• NE Sensor (NE) - - - - - - - - - - - - - - - - - - - - - - This sensor, which detects the camshaft position of the pump,also inputs the number of revolutions of the pump (one-half thenumber of revolutions of the engine) to the engine ECU.• Fuel Temperature Sensor (THF) - - - - - - - - - - This sensor detects the temperature of the fuel.• Correction Resistor or ROM - - - - - - - - - - - - - This part makes corrections to the injection quantity and injection timing.• Timing Control Valve (TCV)- - - - - - - - - - - - - - This actuator, which performs the function of the timer of theprevious distributor type pump, controls the injection timing.11Composition and Construction of ECD-V3 Pump SystemFeedPumpFuel FilterFuel Temperature SensorNE SensorOverflowValveSolenoid SpillValveNozzlePressure ChamberDelivery ValveTiming Control Valve PlungerFuel TankSensor Signal(NE Signal)Solenoid Spill Valve Actuation SignalIntake Temperature SensorThrottleCoolant Temperature SensorIntake Pressure SensorCrankshaft Position SensorAccelerator Position SensorSensor SignalCrankshaftPosition SensorSensor PositionEngine ECUTiming Control Valve(TCV)Timer PistonSolenoid Spill Valve (SPV)Pressure ChamberDelivery PumpPlungerCam PlateRegulating ValveNE Sensor (NE)Fuel Temperature Sensor (THF) 10SERVICE TECH Vol.465 03-4 The mechanism for the suction and pumping/distribution of the fuel is basically the same as for the previousdistributor type pump. However, it differs in the aspect that it controls the fuel injection quantity by opening andclosing a solenoid spill valve by way of electric signals. The solenoid spill valve is provided in the passage thatlinks the pump chamber with the pressure chamber. As the plunger descends, it draws fuel from the suction port into the pressure chamber. At this time, the solenoidspill valve is energized and closed. The plunger ascends while rotating, in order to pressurize and pump the fuel in the pressure chamber. When the solenoid spill valve is no longer energized, the spill valve opens. Then, the high-pressure fuel in thepressure chamber spills into the pump chamber, thus reducing its pressure and ending the injection of fuel.Suction Port : openDistribution Port : closedSolenoid Spill Valve: closedSuction Port : closedDistribution Port : openSolenoid Spill Valve: closedSuction Port : closedDistribution Port : openSolenoid Spill Valve: open22Operation of ECD-V3 Pump2-1 Fuel Suction and InjectionSuction StrokeSolenoid Spill Valve(closed)Speed SensorPlunger Distribution Port (closed)Suction Port (open)to NozzleCam PlateRoller RingPulsarDrive ShaftPressure ChamberPump ChamberPumping Stroke (Injection)Solenoid Spill Valve(closed)Distribution Port (open)Suction Port (closed)End of InjectionSolenoid Spill Valve(open)Suction Port (closed)Distribution Port (open) SERVICE TECH Vol.465 03-411 The solenoid spill valve, which is located in the passage that links the pump chamber of the injection pump with thepressure chamber, is a type of solenoid valve that turns ON/OFF (opens and closes) in accordance with the signalsfrom the engine ECU. When the coil of the solenoid spill valve is energized, the spill valve closes, thus closing the passage that links thepressure chamber with the pump chamber. As a result, the plunger pressurizes the fuel in the pressure chamber andpumps it into the nozzles through which the fuel is injected. When the solenoid spill valve is no longer energized, the spill valve opens, thus opening the passage between thepressure chamber and pump chamber. The pressurized fuel spills into the pump chamber, thus decreasing thepressure in the pressure chamber and ending the pumping of fuel. The solenoid spill valve is directly related to the control of the fuel injection volume. Therefore, it must provide highlevels of precision, quick response, and pressure resistance, as well as a large spill volume. There are two types of solenoid spill valves: the pilot valve type, and the direct-acting solenoid valve type. Thedirect-acting solenoid valve type is widely used today. The pumps are classified into the ECD-V3, ECD-V3 (ROM), and ECD-V3 direct-acting valve types, depending onthe type of solenoid spill valve and the injection volume correction method that are being used.Coil energized valve closed (during suction or injection)Coil non-energized . valve open (end of injection)Type CharacteristicCorrection MethodSolenoid Spill Valve (SPV)ECD-V3 An externally mounted correction resistor is able to correct the final injection quantity.Correction ResistorECD-V3(ROM) The data of an externally mounted ROM is used to correct the final injection quantity. It realizes a higher precision level of correction than the previous type (correction resistor). ROMECD-V3 Direct-Acting Valve Types A direct-acting SPV is used to achieve high levels of response and spill performance.ROM33Solenoid Spill Valve (SPV)Solenoid Spill ValvePlungerPressureChamberCoilto NozzlePump ChamberValve3-1 Types of Solenoid Spill ValvesPilot Valve TypeDirect-Acting Type 12SERVICE TECH Vol.465 03-4 This solenoid spill valve provides a quick response at a higher level of precision. It consists of a spool valve anda solenoid coil. The spool valve, which acts directly in accordance with electric signals, opens and closes thepassage that links the pressure chamber and the pump chamber. This type consists of a main valve, pilot valve, and a solenoid coil. When the solenoid coil is energized, it pulls onthe pilot valve (downward in the diagram), thus closing the pilot spill port. At this time, the high-pressure fuel, which flowed in from the pressure chamber via the restriction, fills the mainvalve. The resulting hydraulic pressure firmly closes the main valve. When the solenoid coil is no longer energized, the pilot valve opens, allowing the fuel in the main valve to spillthrough the pilot spill port. Thus, the pressure in the main valve decreases suddenly. This pressure differencecauses the main valve to open considerably, effectively ending the injection of fuel.Pilot Valve TypeSolenoid Spill ValveCoilPilot ValveMain ValvePressure ChamberPlungerMain SpringControl SpringPilot SpringPilot Valve TypeDirect-Acting Solenoid Valve TypeSpool ValveSpring ArmatureCoilCoreCoilSpringValve BodyValve BodySpool ValveCross Section ViewEnlargement View . (NE) - - - - - - - - - - - - - - - - - - - - - - This sensor, which detects the camshaft position of the pump, also inputs the number of revolutions of the. Spill Valve (SPV) - - - - - - - - - - - - - - This actuator, which performs the function of the spill ring of theprevious distributor type pump, controls