Land Rover Common Rail System Crs Denso Manual
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Operation Section1–76
7.2 E-EGR System (Electric-Exhaust Gas Recirculation)
(1) General Description
• The E-EGR system is an electronically controlled EGR system. The EGR system recirculates a portion of the exhaust
gases into the intake manifold in order to lower the combustion chamber temperature and reduce NOx emissions.
However, operation of the EGR system may reduce engine power output and affect drivability. For this reason, in the
E-EGR system, the engine ECU controls the EGR to achieve an optimal EGR amount.
Operation Conditions Example
- This operates in the operation region fulfilling the starting conditions below (one example).
(2) Operation
• After the vacuum pump generates a vacuum, the E-VRV (electric-vacuum regulation valve) regulates the vacuum and
directs it to the diaphragm chamber of the EGR valve. In response to this vacuum, the diaphragm pushes the spring
downward, which determines the opening of the EGR valve and controls the EGR volume.
• The EGR cooler, which is provided in the EGR passage between the cylinder head and the intake passage, cools the
EGR in order to increase the EGR volume.
• The EGR cutoff VSV, which opens the diaphragm chamber to the atmosphere when the EGR valve is closed, helps
to improve response.
Injection Quantity
Engine Speed
· Engine Operating Conditions
· · · · · Except during engine warm-up and startup,
does not overheat, etc.
· EGR Operating Range
· · · · · · · · For Engine Medium Load
Q000501E
Q000903E
EGR CoolerEGR Valve
CoolantDiaphragm
Vacuum Damper
Spring
EGR Shut-Off VSVVacuum Pump
E-VRV
Control UnitEngine Speed
Accelerator Opening
Intake Air Pressure And
Atmospheric Pressure
Coolant Temperature
Intake Air
Relationship Between Vacuum and EGR Valve Opening
Low
SmallHigh
Large Vacuum
EGR Valve Opening
Engine
Exhaust
Manifold
Operation Section1–77 To Increase the EGR Quantity - The E-VRV duty ratio is controlled *1. In the stable condition shown in the bottom center diagram, an increase in the current that is applied to the coil causes the attraction force FM in the coil to increase. When this force becomes greater than the vacuum force FV that acts on the diaphragm, the moving core moves downward. Along with this movement, the port from the vacuum pump to the upper chamber of the diaphragm opens. Consequently, the out- put vacuum increases, which causes the EGR valve to open and the EGR volume to increase. Meanwhile, because increased output vacuum equals increased FV, the moving core moves upward with the increase in FV. When FM and FV are equal, the port closes and the forces stabilize. Because the vacuum circuit of the EGR is a closed loop, it maintains the vacuum in a stabilized state, provided there are no changes in the amperage. < NOTE > *1 : The engine ECU outputs sawtooth wave signals with a constant frequency. The value of the current is the effective (average) value of thesesignals. For details, see the explanation of the HP3 supply pump and SCV. To Decrease the EGR Volume - A decrease in the current that is applied to the coil causes FV to become greater than FM. As a result, the dia- phragm moves upward. The moving core also moves upward in conjunction with the movement of the diaphragm, causing the valve that seals the upper and lower diaphragm chambers to open. Consequently, the atmospheric pressure in the lower chamber enters the upper chamber, thus reducing the output vacuum. This causes the EGR valve to close and the EGR volume to decrease. Because decreased output vacuum equals decreased FV, the moving core moves downward with the decrease in FV. When FM and FV are equal, the port closes and the forces stabilize. FV FM FM > FV EGR Quantity Increased FM < FV EGR Quantity Decreased To EGR ValveFrom Vacuum Pump Atmosphere Va l v e Spring Coil Stator CoreDiaphragm Moving Core Q000904E
Operation Section1–78 7.3 Electronically Controlled Throttle (Not Made By DENSO) (1) General Description • The electronically controlled throttle is located upstream of the EGR valve in the intake manifold. It controls the throttle valve at an optimal angle to regulate the EGR gas and reduce noise and harmful exhaust gases. (2) Operation • Signals from the engine ECU actuate the stepping motor, which regulates the throttle valve opening. EGR Control • To further increase the EGR volume when the EGR valve is fully open, the vacuum in the intake manifold can be in- creased by reducing the throttle valve opening, which restricts the flow of the intake air. Noise and Exhaust Gas Reduction • When the engine is being started, the throttle valve opens fully to reduce the emissions of white and black smoke. • When the engine is being stopped, the throttle valve closes fully to reduce vibration and noise. • During normal driving, the throttle valve opening is controlled in accordance with the engine conditions, coolant tem- perature, and atmospheric pressure. Stepping Motor Throttle Valve Q000905E
Operation Section1–79 7.4 Exhaust Gas Control System (1) General Description • The exhaust gas control system is provided to improve warm-up and heater performance. This system actuates the exhaust gas control valve VSV, which is attached to the exhaust manifold. It increases the exhaust pressure to in- crease the exhaust temperature and engine load, in order to improve warm-up and heater performance. (2) Operation • The exhaust gas control system operates when the warm-up switch is ON, and all the conditions listed below have been met. Operation Conditions - The EGR is operating. - The coolant temperature is below 70°C. - The ambient temperature is below 5°C. - A minimum of 10 seconds have elapsed after starting the engine. - The engine speed and fuel injection quantity are in the state shown in the graph below. Air CleanerExhaust Gas Control Valve Exhaust Gas Control ValveVacuum Pump VSV Turbo Pressure Sensor Coolant Temperature Sensor EGR Valve Position Sensor Warm-Up SwitchMass Airflow Meter Cylinder Recognition Sensor (TDC (G) Sensor) Accelerator Position Sensor Atmospheric Pressure Sensor ECU Q000906E Q000907E WARM UP Engine SpeedOperating Range Extremely Low Torque or Engine Speed Range [Exhaust Gas Control System Operating Range] Injection Quantity
Operation Section1–80 7.5 DPF System (Diesel Particulate Filter) (1) General Description • This system reduces emissions of PM (particulate matter). In order to collect PM, a DPF cleaner with built-in catalytic filter is mounted on the center pipe. The collected PM is handled with combustion processing during operation. (2) System Configuration (3) Various Sensors Exhaust Gas Temperature Sensor • The exhaust gas temperature sensor is installed to the front and rear of the DPF to detect the temperature in these positions. The engine ECU controls the exhaust temperature for PM combustion based on the signals from this sen- sor. The sensor element is a thermistor. Q000908E Rail G2 Injector Intercooler VNT Actuator Equilibrium ActuatorEGR CoolerIntake Air Pressure Sensor EGR Valve Supply Pump DPF (with Oxidation Catalyst)Exhaust Gas Temperature Sensor Exhaust Gas Temperature Sensor Differential Pressure SensorECU & EDU Q000909EExhaust Gas Temperature ( ) Thermistor Element Cover Resistance Value ( )
Operation Section1–81 Differential Pressure Sensor • The differential pressure sensor detects the difference in pressure at the front and rear of the DPF, and outputs a sig- nal to the engine ECU. The sensor portion is a semiconductor type pressure sensor that utilizes the piezoelectric ef- fect through a silicon element, and amplifies and outputs the voltage with its IC circuit. When PM is collected and accumulated in the DPF, the filter clogs and the difference in pressure at the front and rear of the DPF increases. Therefore, based on the signals from this sensor, the engine ECU judges whether or not to subject PM to combustion processing. (4) Operation • By optimizing the injection pattern and controlling the exhaust gas temperature based on the exhaust gas temperature and the difference in pressure at the front and rear of the DPF, PM is collected, oxidized, and self-combusted. When the exhaust temperature is low, adding after-injection after the main injection raises the exhaust gas temperature to approximately 250?C and promotes oxidation of the PM. When the PM is collected and accumulated, the post-injec- tion is added and HC is added to the catalyst to raise the catalyst temperature to 600?C, which is the self-combustion temperature for PM. This combusts the accumulated PM in a short time. The engine ECU controls the A, B, and C times and the injection times. Q000910E GND V P VC Pressure (kPa) Output Voltage VP (V) TDC A B CAfter-Injection Post-Injection Q000506E
Operation Section1–82 7.6 DPNR SYSTEM (DIESEL PARTICULATE NOx REDUCTION) (1) General Description • This system reduces the emissions of PM (particulate matter) and NOx. The DPNR catalyst mounted in the center pipe collects and regenerates PM and reduces NOx all at the same time. The collected PM is handled with combus- tion processing during operation. (2) System Configuration Q000911E Supply PumpExhaust Gas Cleaning Device SwitchExhaust Gas Cleaning Device Display Lamp Injector DPNR Catalyst Oxidation Catalyst A/F Sensor Exhaust Gas Temperature Sensor Differential Pressure SensorNSR A/F Sensor Fuel Addition Valve Oxidation Catalyst Before EGR Cooler Engine ECU Exhaust Retarder VSV Exhaust Retarder Intake Restriction Valve
Operation Section1–83 8. DIAGNOSIS 8.1 Outline Of The Diagnostic Function zThe diagnostic function enables a system to self-diagnose its own malfunctions. If abnormal conditions occur in the sen- sors or actuators used in the control systems, the respective systems convert the malfunction signals into codes and transmit them to the engine ECU. The engine ECU records the transmitted malfunction code into memory. Recorded codes are output at the diagnostics connector on the vehicle. To inform the driver of the malfunction, the engine ECU causes the MIL (Malfunction Indicator Light) in the meter to illuminate. Accurate troubleshooting can be performed by way of the DTCs (Diagnostic Trouble Codes) that are output at the diagnostic connector. For details on actual diagnosis codes, see the vehicle manual. It is necessary to put the vehicle into the state below before starting inspection. (1) Pre-Inspection Preparation • Position the shift lever in N or P. • Turn OFF the air conditioner. • Verify that the throttle valve is fully closed. 8.2 Diagnosis Inspection Using DST-1 zThe DST-1 can be used in both normal and check modes. Compared to the normal mode, the check mode has a higher sensitivity to detect malfunctions. zThe check mode inspection is performed when normal codes are output in the normal mode, despite the fact that there may be malfunctions in the sensor signal systems. (1) Reading DTCs 1)DST-1 Connection: Connect the DST-1 to the DLC3 termi- nal. 2)Reading DTCs: Operate in accordance with the instructions shown on the screen to display the DTC check screen. Se- lect either the normal or check mode and read the DTC. < NOTE > If no DTC appears on the screen, there may be a failure in the engine ECU. 16 15 14 13 12 11 10 9 87654321DLC3 Q000914 Diagnostic Trouble Codes (DTC) 1. · · · Execute: Execute Q000915E
Operation Section1–84 3)Checking the Freeze Frame Data: If the symptom that out- puts a DTC cannot be duplicated, check the freeze frame data. 4)Erasing DTCs from memory: Operate in accordance with the instructions shown on the screen to display the DTC check screen. Select Erase DTCs to erase the DTCs. < NOTE > If it is not possible to erase the DTC, turn the ignition switch OFF, and repeat the process. 5)Wiring Harness and Connector Open Circuit Check < NOTE > If the DTC output during a diagnostic inspection (in the check mode) has identified the system with a malfunction, use the method indicated below to narrow down the area of the malfunction. • Erasing DTCs from memory: After reading the DTCs in check mode, erase the DTCs from memory. • Starting the Engine: Select the check mode and start the engine. • Malfunctioning system check 1: While the engine is running at idle, shake the wiring harness and connectors of the system that output the malfunction during the diagnosis (check mode) inspection. • Malfunctioning system check 2: If the MIL (Malfunction Indicator Light) illuminates when the wiring harness and con- nectors are shaken, there is a poor contact in the wiring harness or connectors in that area. 8.3 Diagnosis Inspection Using The MIL (Malfunction Indicator Light) zBefore reading a DTC, turn the ignition switch ON to make sure the MIL (Malfunction Indicator Light) illuminates. zInspections in the check mode cannot be performed. (1) Reading DTCs Short circuiting the connector • Using the STT, short circuit between DLC1 terminals 8 (TE1) and 3 (E1) or between DLC3 terminals 13 (TC) and 4 (CG). < CAUTION > Never connect the wrong terminals of the connectors as this will lead to a malfunction. Q000916E This will erase the DTC and freeze frame data. Do you wish to proceed?DTC (ECD Erasure) NG : - OK : + 4 TE1E1 TC CG 123 5618 789 101120 12 13 1415 16 17 2122 231916 15 14 13 12 11 10 9 87654321 DLC1DLC3 Q000917E
Operation Section1–85 Reading DTCs 1 • Turn the ignition switch ON and count the number of times the MIL (Malfunction Indicator Light) blinks < NOTE > • If the MIL (Malfunction Indicator Light) does not output a code (the light does not blink), there may be an open circuit in the TC terminal system or a failure in the engine ECU. • If the malfunction indicator light is constantly ON, there may be a short (pinching) in the wiring harness or a failure in the engine ECU. • If meaningless DTCs are output, there may be a malfunction in the engine ECU. • If the MIL (Malfunction Indicator Light) illuminates without outputting a DTC while the engine operates at a minimum speed of 1000rpm, turn the ignition switch OFF once; then resume the inspection. Reading DTCs 2 • If an abnormal DTC has been output, check it against the DTC list. Erasing DTCs from memory • Remove the ECD fuse (15A); after 15 seconds have elapsed, re-install the fuse. < CAUTION > After completing the inspection of the ECD system, erase the DTC memory, and make sure the normal code is output. 0.26sec 0.26sec 0.26sec ON OFF ON OFF0.52sec 1.5sec 2.5sec 1.5sec 4.5sec 4.5sec 0.52sec 0.52sec · Normal Operation · Malfunction (Codes 12 and 23 are output.) Jump Terminals TE1 and TCJump Terminals TE1 and TCRepeat Repeat Thereafter Malfunction Indicator Light Q000918E ECD Fuse (15A) Engine Compartment Relay Block Q000919E