Bơm ECD-V - P - Intake Restriction Control

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

"Intake Restriction Control, EGR Control and Glow Control"ECD (Electronically Controlled Diesel): An electronically controlled system for diesel fuel injection.Eighth SessionEighth Session11SERVICE TECH Vol.471 04-4 This control system adjusts the air intake volume of the engine to secure a comfortable and safe drive. The "intake restriction valve (sub valve)" located halfway along the intake manifold opens and closes accordingto the engine conditions. This reduces noise and vibration, and prevents overrun.Main Operations ObjectiveWhen starting the engineFully opens the sub valve to minimize the emission of white smoke and black smokeWhen idlingRestricts the air intake volume to reduce noiseWhen engine is stoppedFully closes the sub valve to reduce engine vibration and noiseDuring Abnormally high engine speedFully closes the sub valve to prevent overrun The sub valve installed in parallel to the main valve can be moved to 3positions, "Fully open, Half open, or Fully closed", with the 2 leveldiaphragm. This is how the air intake volume is controlled.11Intake Restriction Control1-1 Control Outline1-22 Level Diaphragm Type Intake Restriction MechanismSub Valve2 Level DiaphragmVacuum PumpAir2 Level DiaphragmChamber BSubValveMainValveAcceleratorPedalAccelerator PositionEngine SpeedKey SwitchRefrigerant TemperatureVacuumEngine ECUVSV1VSV2Chamber AAir 12SERVICE TECH Vol.471 04-4This component is constructed from 2 diaphragms and springs, and a rod. Chamber A and chamber B areseparated by the diaphragms. When a vacuum or air pressure is introduced to these chambers the rod moves,which via the link makes the sub valve move to one of the 3 positions. This is a solenoid valve that selects the airflow ports according to the signal received from the engine ECU,switching the pressure feed to the diaphragm chamber. The energization of VSV1 or VSV2 is selected according to the driving and engine conditions. A vacuum or airpressure is channeled into the diaphragm chamber, which moves the sub valve to one of 3 positions and adjuststhe intake air volume.Active Air FlowPort E Port F Air PortEnergized (ON)NotEnergized1-3 Component Construction and Operation2 Level DiaphragmVacuumVacuumVacuum Air PressureAir PressureAir PressureRodChamber BSpringChamber AFully Open Half Open Fully ClosedVSV (Vacuum Switching Valve)Air PortE PortF PortChamber A or Chamber B Diaphragm PortToFromVacuumPort1-4 Intake Restriction Position and Driving ConditionsSub Valve PositionFully OpenHalf OpenFully ClosedActuatorVSVVSV1OFFOFFAir Pressure Air PressureVacuumVacuumAir PressureVacuumONONONOFFVSV2Chamber A Chamber BDiaphragm ChamberDriving Conditions• When starting (starter ON)• When idling during warm-up• When driving• When idling after warm-up• When engine stalled (IG/ON)• When abnormally high engine speed is detected• For 2 seconds after stopping the engine• When overrun is detected• When SPV abnormality is detectedEngine Conditions 13SERVICE TECH Vol.471 04-4Part of the exhaust gas is recirculated to the intake side, which slows combustion and controls NOx emissions.In EGR (Exhaust Gas Recirculation) control, an amount of exhaust gas appropriate to the driving conditions isreturned to the intake manifold and reinserted in the combustion process. This system lowers the combustiontemperature and reduces nitrogen oxide (NOx) emissions.• EGR Valve This component is constructed from a diaphragm, spring and valve. When a vacuum is introduced to thediaphragm chamber, a valve that is interlinked with the diaphragm opens. The exhaust gas flows from theexhaust manifold to the intake manifold side.• E-VRV (Electric Vacuum Regulating Valve)This is a solenoid valve for switching the vacuum. Duty control is performed by the engine ECU. When thesolenoid valve goes on or off, the vacuum from the vacuum pump is switched, which controls the vacuum feedto the diaphragm chamber of the EGR valve.Duty Control This control utilizes the duty ratio. The duty ratio is the ratio of energized (ON)duration to non-energized (OFF) duration. Itis calculated using the following formula, inwhich the ON duration (t) is divided by theunit of time (T).22EGR Control Outline2-1 Control OutlineInjection PumpVacuum Pump(Vacuum)Exhaust ManifoldEngine Speed SignalAccelerator Position SignalThrottle Position SensorDiaphragm ChamberAirEGR ValveCoolant Temperature SensorEngine ECUComponent Construction and OperationFilterEGR ValveVacuum PumpCoilEGR Valve E-VRVDuty Ratio = × 100 (%)TtONtTOFF 14SERVICE TECH Vol.471 04-4This control improves startability during cold weather and reduces emission gases and noise.The heat generating part is a "ceramic glow plug" that uses a conductive ceramic heating element.The resistance at ordinary temperatures is about 0.5 , and when current flows it rapidly generates heat.However as the temperature increases the resistance of the control coil also increases, and the electric volumegradually decreases. This "self control function" maintains a roughly constant temperature. A heat source installed in the engine combustion chamber improvesstartability by both warming the air inside the combustion chamber andby acting as an ignition source for the fuel. In addition, even after the engine is started, it generates heat for alimited time to reduce the emission of white smoke and diesel knocknoise.33Glow Control Outline3-1 Control OutlineGlow PlugAuxiliaryCombustionChamberGlow RelayGlow PlugGlow PlugIndicator LampCoolantTemperatureSensorEngineECU3-2 Glow PlugType With Control Coil48Energization Time (Sec.)Self Control FunctionTemperature(°C)121000Ceramic Glow PlugCeramic Glow PlugCeramic Heating Element(Resistance at Ordinary Temperatures : About 0.5 ) . air intake volume is controlled.1 1Intake Restriction Control 1-1 Control Outline 1-2 2 Level Diaphragm Type Intake Restriction MechanismSub Valve2 Level DiaphragmVacuum. BSpringChamber AFully Open Half Open Fully ClosedVSV (Vacuum Switching Valve)Air PortE PortF PortChamber A or Chamber B Diaphragm PortToFromVacuumPort 1-4