SERVICE MANUAL - Service
Contents
1. 2 1 System Characteristics 2 2 Comparison to the Conventional System 3 2 2 Outline of System 4 1 Composition 4 2 Operation 4 3 Fuel System 5 4 Control System 5 3 Construction and Operation 6 3 1 Description of Main Components 6 1 Supply Pump HP3 6 2 Description of Supply Pump Components 11 3 Rail2. STA ON duration STA ON duration aH STA ON Starting STA ON Starting 6 Idle Speed Control ISC System This system controls the idle speed by regulating the injection quantity in order to match the actual speed to the target speed that is calculated by the engine ECU The target speed varies according to the type of transmission manual or automatic whether the air conditioner is ON or OFF the shift position and the coolant water temperature 7 Idle Vibration Reduction Control To reduce engine vibrations during idle this function compares the angle speeds times of the cylinders and regulates the injection quantity for the individual cylinders if there is a large the difference in order to achieve a smooth engine operation Correction Crankshaft angle gt Crankshaft angle QC0043E 3 Fuel Injection Timing Control 1 Outline Fuel injection timing is controlled by varying the timing in which current is applied to the in jectors 2 Main and Pilot Injection Timing Control Main Injection Timing The engine ECU calculates the basic injection timing based on the engine speed the final injection quantity and adds various types of corrections in order to determine the optimal main injection timing Pilot Injection Timing Pilot Interval Pilot injection timing is controlled by adding a pilot interval to the main injection timing The pilot interval is calculated based on the final inj
3. 14 A Injector 2 2 nnn nnn nnn nnn nnn nnn a 16 3 2 Description of Control System Components 19 1 ECU Electronic Control Unit 19 2 Description of Sensors 19 3 EGR Valve Exhaust Gas Recirculation Valve 21 3 3 Various Types of Controls 22 1 Outline 22 2 Fuel Injection Quantity Control 23 3 Fuel Injection Timing Control 25 4 Fuel Injection Rate Control 26 5 Fuel Injection Pressure Control 26 6 Other Controls 26 4 External Wiring Diagram 27
4. NOx and noise Small first stage combustion Heat release rate 20 20 40 20 20 40 Crankshaft angle deg gt Crankshaft angle deg gt 5 Fuel Injection Pressure Control A value that is determined by the final injection quantity the water temperature and the engine speed is calculated During the starting of the engine the calculation is based on the water tem perature and the atmospheric pressure Rail pressure Final injection quantity Engine speed 6 Other Controls a Limit maximum injection quantity b Gradual acceleration injection quantity c Gradual deceleration injection quantity d Post acceleration damping injection quantity e Reference injection quantity f Fuel cutoff g Turbo control h Glow plug relay i EGR control 26 4 External Wiring Diagram 4 1 ECU External Wiring Diagram Twist pair Injector COMMON1 E55 12V REF VU E52 0 PL INVV1 E50 0 PL INVV3 COMMON2 E51 12V REF E56 0 PL INVV2 E53 0 PL INVV4 Twist pai E54 E49 Shield wire G jin G E40 1 F CAM G KE ee II feo VH E28 S S SVREF CAM E15 S R 5VREF NE LL eet enne EE SH GND Shield wire E16 GSFGND PATM VCC E18 S S 5VREF PATM roue en PATM GND E6 S R SVRTN THW GND E17 S R 5VRTN THW E30 1 AH CLT THF GND E5 S R 5VRTN Fuel temp THF E43 1 AH FUELT PIM VCC E9 S S 5VREF PIM1 E44 l A BOOSTP PIM GND E22 S R 5VRTN At
5. quantity t Individual cvlinder correction Injection pressure correction Mass airflow correction Intake air temperature correction Atmospheric pressure correction Cold operation maximum injection quantitv correction Injection quantitv Engine speed Q000061E 3 Basic Injection Quantity The basic injection quantity is determined by the engine speed NE and the accelerator po sition The injection quantity is increased when the accelerator position signal is increased while the engine speed remains constant Basic injection quantity Accelerator position Engine speed 23 4 Maximum Injection Quantitv The maximum injection quantitv is calculated bv adding the mass airflow correction intake air temperature correction atmospheric pressure correction and the cold operation maxi mum injection quantitv correction to the basic maximum injection quantitv that is determined bv the engine speed Basic maximum injection quantitv Engine speed 5 Starting Injection Quantitv When the starter switch is turned ON the injection quantitv is calculated in accordance with the starting base injection quantitv and the starter ON time The base injection quantitv and the inclination of the quantitv increase decrease change in accordance with the coolant tem perature and the engine speed Coolant temperature 7 High lt gt Low eg SS Injection quantity Injection quantity Base injection quantity
6. 4 1 ECU External Wiring Diagram 27 4 2 ECU Connector Diagram 9 222 022 2222 22 29 1 ECU Connector Terminal Layout 29 2 Terminal Connections 9 29 1 Product Application 1 1 Application Vehicle Name Vehicle Model Engine Model Exhaust Volume E Made in Germany Vehicle Model DENSO Part Car Manufacturer Part Name CI A o rosas mae mese A Io Lee mae el Immens sro Grint Postonsanso o o zeen mam Opina Rectan Sewer 97 o zeen mae korvas o o muros oraso 2 Outline 2 1 Outline of Svstem The common rail svstem was developed primarilv to cope with exhaust gas regulations for die sel engines and aimed for 1 further improved fuel economv 2 noise reduction and 3 high power output 1 System Characteristics The common rail system uses a type of accumulation chamber called a rail to store pressurized fuel and injectors that contain electronically controlled solenoid valves to spray the pressurized fuel into the cylinders Because the engine ECU controls the injection system including the in jection pressure injection rate and injection timing the injection system is unaffected by the engine speed or load This ensures a stable i
7. Outline of Svstem 1 Composition The common rail system consists primarily of a supply pump rail injectors and engine ECU Fuel temperature sensor Vehicle speed Accelerator opening Intake air pressure gt Intake air temperature Coolant temperature Crankshaft position Cylinder recognition sensor Engine ECU Intake airflow rate Pressure limiter Rail pressure sensor OC a SA Supplv pum SCV suction ae kadi control valve Fuel tank Fuel temperature sensor 2 Operation 1 Supply pump HP3 The supply pump draws fuel from the fuel tank and pumps the high pressure fuel to the rail The quantity of fuel discharged from the supply pump controls the pressure in the rail The SCV Suction Control Valve in the supply pump effects this control in accordance with the command received from the ECU 2 Rail The rail is mounted between the supply pump and the injector and stores the high pressure fuel 3 Injector This injector replaces the conventional injection nozzle and achieves optimal injection by ef fecting control in accordance with signals from the ECU Signals from the ECU determine the length of time and the timing in which current is applied to the injector This in turn de termines the quantity rate and timing of the fuel that is injected from the injector 4 Engine ECU The engine ECU calculates data received from the sensors to comprehensively control the i
8. chamber Control chamber Control chamber pressure pressure y pressure D A pi AJ Nozzle Injection rate Injection rate needle Command piston End of injection Q000149E 5 QR Code QR Quick Response codes have been adopted to enhance the injection quantitv precision of the injectors The adoption of QR codes enables injection quantitv dispersion control throughout all pressure ranges contributing to improvement in combustion efficiencv reduc tions in exhaust gas emissions and so on QR Code Correction Point 180 MPa 140 MPa Injection Quantitv Q Actuating Pulse Width Tq QR Code 9 9 mm D Code 22 sets of 16 alphanumeric figures Contents of Printing Q000150E 3 2 Description of Control System Components 1 ECU Electronic Control Unit This is the command center that controls the fuel injection system and engine operation in general Outline Diagram Sensor Engine ECU Actuator Calculation Actuation 2 Description of Sensors Q000152E 1 Crankshaft Position Sensor NE sensor The NE sensor is an MRE Magnetic Resistance Element type sensor It is positioned above the crankshaft to detect the crankshaft position The pulsar gear is composed of 56 gears with 4 gears missing per 1 revolution and the sensor outputs 56 pulses for each 1 revolution of the crankshaft 36
9. se n 2 Supply Pump Internal Fuel Flow The fuel that is drawn from the fuel tank passes through the route in the supplv pump as il lustrated and is fed into the rail Supplv pump interior E Regulating valve Feed pump SCV Suction Control Valve Discharge valve ffe an Pumping tl pungen Fuel tank 3 Construction of Supply Pump The eccentric cam is formed on the drive shaft The ring cam is connected to the eccentric cam Drive shaft Eccentric cam Ring cam As the drive shaft rotates the eccentric cam rotates in the eccentric state and the ring cam moves up and down while rotating The plunger and the suction valve are mounted on top of the ring cam The feed pump is con nected to the rear of the drive shaft Feed pump 4 Operation of the Supply Pump As shown in the illustration below the rotation of the eccentric cam causes the ring cam to push Plunger A upwards Due to the spring force Plunger B is pulled in the opposite direction to Plunger A As a result Plunger B draws in fuel while Plunger A pumps it to the rail Suction valve Delivery valve Eccentric cam Plunger A complete compression Plunger A begin intake Plunger B complete intake Plunger B begin compression Plunger A begin compression Plunger A complete intake Plunger B begin intake Plunger B complete compression QDO707E 2 Description of Supply Pump Components 1 Feed Pump The trochoid type feed p
10. 0 CA Exterior Drawing Circuit Diagram Vcc O E Q000154E 2 Cylinder Recognition Sensor G sensor The cylinder recognition sensor G sensor is an MRE Magnetic Resistance Element type sensor It detects the engine cylinders and outputs 5 pulses for every two revolutions of the engine 720 CA Exterior View Diagram Circuit Diagram O O G input circuit GA Q000155E 3 Fuel temperature sensor THF Detects the fuel temperature and sends a corresponding signal to the engine ECU Based on this information the engine ECU calculates the injection volume correction that is appropriate for the fuel temperature Resistance Value Characteristics CC k9 Fuel temperature sensor pO 6 Cal osa 80 0318 0031 al 0240 20 3 EGR Valve Exhaust Gas Recirculation Valve 1 EGR Valve Construction An EGR valve is utilized as the system actuator for the electric exhaust gas recirculation E EGR system It is constructed of an upper section and a lower section The upper section receives output signals from the engine ECU and contains a solenoid that generates elec tromagnetic force The lower section is constructed of a nozzle that moves up and down in response to the electromagnetic force and a valve with an opening that alters in response to the nozzle position 2 EGR Valve Operation The E EGR system electronically controls the EGR The EGR system reduces NOx by low ering the
11. 200 Rail pressure MPa Q000053E 3 Pressure Limiter The pressure limiter relieves pressure by opening the valve if abnormally high pressure is generated The valve opens when pressure in rail reaches approximately 230 MPa and closes when pressure falls to approximately 50 MPa Fuel leaked by the pressure limiter re turns to the fuel tank Ball valve 4 Injector 1 Outline The injectors inject the high pressure fuel from the rail into the combustion chambers at the optimum injection timing rate and spray condition in accordance with commands received from the ECU 2 Characteristics e A compact energy saving solenoid control type TWV Two Way Valve injector has been adopted e QR codes displaying various injector characteristics are laser marked in the injector body and ID codes showing these in numeric form 22 alphanumeric figures are laser marked on the connector head e This system uses QR code information to optimize injection quantity control When an injector is newly installed in a vehicle it is necessary to input the ID codes in the ECU 3 Construction 22 characters Solenoid valve A Ea Ab las I High pressure fuel from Rail Command piston spring Nozzle spring Seat area IT Yu ES Gs UE a Nozzle needle Q000148E 4 Operation The TWV valve opens and closes the outlet orifice to control the hvdraulic pressure in the control chamber and the s
12. For DENSO Authorized ECD Service Dealer Only Diesel Injection Pump No E 03 04 SERVICE MANUAL Common Rail System for OPEL 4EE2 Type Engine Operation August 2003 DENSO CORPORATION 00400028 FORWARD To meet the high pressurization requirements for the engine to deliver cleaner exhaust gas emissions lower fuel consumption and reduced noise advanced electronic control technologv is being adopted in the fuel injection svstem This manual covers the electronic control model Common Rail svstem with HP3 pump for the ISUZU 4EE2 type engine which is used to OPEL CORSA and MERIVA Complex theories spe cial functions and components made by manufacturers other than DENSO are omitted from this manual This manual will help the reader develop an understanding of the basic construction operation and system configuration of the DENSO manufactured components and brief diagnostic infor mation TABLE OF CONTENTS 1 Product Application 1 1 1 Application 1 1 2 System Components Parts Numbers 1 2 Outline ono nnn nnnnnnnnnnnnnnnnnnnnnnnnnnnnnn nnana nnana nnnl 2 2 1 Features of System
13. combustion temperature This is done recirculating a portion of the exhaust gases through the intake manifold Because this system also reduces the engine output and affects driveability the E EGR system effects computer control to achieve an optimal EGR volume in accordance with the driving conditions Exterior View Q000153E 21 3 3 Various Tvpes of Controls 1 Outline This system effects fuel injection quantity and injection timing control more appropriately than the mechanical governor and timer used in the conventional injection pump The engine ECU performs the necessary calculations in accordance with the sensors installed on the engine and the vehicle It then controls the timing and duration of time in which current is applied to the injectors in order to realize both optimal injection and injection timing 1 Fuel Injection Quantity Control Function The fuel injection quantity control function replaces the conventional governor function It controls the fuel injection to an optimal injection quantity based on the engine speed and ac celerator position signals 2 Fuel Injection Timing Control Function The fuel injection timing control function replaces the conventional timer function It controls the injection to an optimal timing based on the engine speed and the injection quantity 3 Fuel Injection Rate Control Function Pilot injection control injects a small amount of fuel before the main injection 4 Fuel Inje
14. ction Pressure Control Function Rail Pressure Control Function The fuel injection pressure control function rail pressure control function controls the dis charge volume of the pump by measuring the fuel pressure at the rail pressure sensor and feeding it back to the ECU It effects pressure feedback control so that the discharge volume matches the optimal command value set in accordance with the engine speed and the in jection quantity 22 21 Fuel Injection Quantitv Control 1 Outline This control determines the fuel injection quantitv bv adding coolant temperature fuel tem perature intake air temperature and mass airflow corrections to the basic injection quantitv is calculated bv the engine ECU based on the engine operating conditions and driving con ditions 2 Injection Quantitv Calculation Method The basic injection quantity is obtained through the governor pattern calculated from the accelerator position and the engine speed The basic injection quantity is then compared to the maximum injection quantity obtained from the engine speed to which various types of corrections are made The smallest injection quantity is then used as the basis for the final injection quantity Accelerator position Injection quantity Engine speed Accelerator position Basic injection quantity PREV Final injection 8 l quantitv after Driver actuation Engine speed speed correction timing calculation Maximum injection
15. d full quantity discharge e When the SCV is ON the force of the return spring moves the cylinder to the right closing the fuel passage normally opened e By turning the SCV ON OFF fuel is supplied in an amount corresponding to the actuation duty ratio and fuel is discharged by the plungers Pump body Exterior view of SCV Cross section of SCV Q000050E In case of short dutv ON Short dutv ON large valve opening maximum intake quantitv Ee EE In case of long duty ON Long duty ON small valve opening 7 minimum intake quantity EE z7 ii Y P Small opening Cylind 3 Rail 1 Outline e Stores pressurized fuel 0 to 180 MPa that has been delivered from the supply pump and distributes the fuel to each cylinder injector A rail pressure sensor and a pressure limiter are adopted in the rail e The rail pressure sensor Pc sensor detects the fuel pressure in the rail and sends a signal to the engine ECU while the pressure limiter controls the fuel pressure in the rail Pressure limiter Rail pressure Pc sensor Q000147E 2 Rail Pressure Pc Sensor This sensor detects fuel pressure in the rail and sends a signal to the ECU It is a semi con ductor type pressure sensor that utilizes the characteristic whereby electrical resistance changes when pressure is applied to silicon Vcc supply voltage F Vout V Vout Pc output voltage sensor GND ground 0
16. der recognition Injection pressure control Cylider recognition sensor G e Engine ECU Load Fuel pressure control Other sensors and switches EGR air intake control relay light Q000047E 3 Construction and Operation 3 1 Description of Main Components 1 Supply Pump HP3 1 Outline e The supply pump consists primarily of the pump body eccentric cam ring cam and plungers SCV Suction Control Valve fuel temperature sensor and feed pump Fuel temperature sensor Q000145E e The two plungers are positioned vertically on the outer ring cam for compactness e The engine drives the supply pump at a ratio of 1 2 The supply pump has a built in feed pump trochoid type and draws the fuel from the fuel tank sending it to the plunger chamber e The internal camshaft drives the two plungers and they pressurize the fuel sent to the plunger chamber and send it to the rail The quantity of fuel supplied to the rail is controlled by the SCV using signals from the engine ECU The SCV is a normally opened type the intake valve opens during de energization Injector Return Discharge valve Fuel tank Fuel overflow mma Camshaft Intake valve Plunger w Intake pressure lt Feed pressure High pressure Return pressure Regulating valve Feed pump Fuel inlet Fuel filter with priming pump O S ET N D 6 N A BON
17. ection proposal HW 0 75mm2 PATM 0 75mm2 PFUEL 0 75mm2 Pin Name Pin Name ISUZU DENSO E31 I AH BAROT S R 5VRTN THF GND E33 I A RAILPS E35 O PL Turbo E Pin Name Pin Name ISUZU DENSO S R 12VRTN G N Oj E3 E5 E6 E7 m wo N m 8 S S 5VREF PFUEL VCC 9 IS S SVREF PIM VCC E BE LEI E m TO ae St E zl m ss T ST 0 75mm m Co N o 12V REF SCV 0 75mm E3 S S 5VREF V G NT 0 75mm2 E E11 E m EN Saar Es ise gt 6 GSFGND SH GND E44 l A BOOSTP PIM1 E E 17 S R 5VRTN THW GND E45 I A EGRP LEGR S S 5VREF PATM VCC E46 15 l F CRANK Lo INE E43 l AH FUELT 1 8 9 E E o ES N E E A Ggs Tanz Es 27 l F CRANK Hi NE E55 12V REF COMMON1 E28 S S 5VREF G VCC E56 O PL INVV2 TWV2 E25 I SH LOWOIL LOIL SW E53 O PL INVV4 m gl E 12 O PL VSS VSS E40 Il F CAM m m m m m m N O B 30
18. ection quantity engine speed coolant tem perature map correction The pilot interval at the time the engine is started is calculated from the coolant temperature and speed Top deadcenter Malminigeton Pilot injection Interval 3 Injection Timing Calculation Method Outline of Control Timing 0 1 Actual TDC NE pulse See l Pilot injection Main injection Solenoid valve control pulse 7 1 Pilot i injection timing Nozzle needle lift L Pilot interval Injection Timing Calculation Method Engine speed Basic injection Main injection timing Corrections timing Injection quantity La air temperature correction Coolant temperature correction Atmospheric pressure correction Q000062E 4 Fuel Injection Rate Control While the injection rate increases with the adoption of high pressure fuel injection the ignition lag which is the delav from the start of injection to the beginning of combustion cannot be shortened to less than a certain value As a result the quantitv of fuel that is injected until main ignition occurs increases resulting in an explosive combustion at the time of main ignition This increases both NOx and noise For this reason pilot injection is provided to minimize the initial injection rate prevent the explosive first stage combustion and reduce noise and NOx Normal Injection Pilot Injection Injection rate Large first stage combustion
19. ler DI E23 O PL I T V11 0 SL GLOWRLY V27 l SL GLOWDIAG BATT Electronic control unit Shield wire Glow PFUEL VCC controller E8 S S 5VREF JL ken E21 1 A RAILPS ioj akoj ME PFUEL e33 A RAILPS E20 S R SVRTN High pressure pump solenoid SCV E11 12V REF E24 0 PL PRESSURE Twist pair CAN H V21 C CANHI SVS Glow V14 0 PL TN EPS V1 O PL FC MID V2 S DATA1 O 1 K line 1 a Immobilizer SAE1962 Oil level Oil press LED warning V33 C CANLO Q000159E 28 4 2 ECU Connector Diagram 1 ECU Connector Terminal Layout Vehicle Side V Engine Side E Q000160E 2 Terminal Connections 1 Vehicle Side V Wire Cross section proposal Wire Cross section proposal O PL FC FUELOUT V29 S R 5VRTN MAF GND S DATA1 ISO K V30 S R 5VRTN PAC GND I SL BRAKE1 BK1 SW V31 S R 5VRTN ACCP2 GND Pin Name Pin Name ISUZU DENSO Pin Name Pin Name ISUZU DENSO 0 75mm2 Vi V2 V3 V5 V6 Q B 7 Il A PPS1 ACCP1 V35 O SL FAN2 FAN2 REL lt oO E E ie O o E wo 00 O SL GLOWRLY GL ST V39 I SL STARTER STA SW V12 0 SL WTGLOW1 HEAT1 REL V40 I SL GEARPOSN CL SW V13 P S IGN IG SW V41 S S 5VREF MAF VCC V11 rem OPINO EAS N V14 O PL TN NEOUT V42 S S 5VREF PAC VCC N N V26 iii ie 2 V27 I SL GLOWDIAG GLOW DI V55 HSGGND P GND 29 2 Engine Side E Wire Cross section proposal Wire Cross s
20. mospheric pressure Boost pressure 1 l Engine side Vehicle Side BATT V50 BATT V56 P S PROTBA 8 V52 P S PROTBA CB V25 0 SL MPR RADA IG SW Key switch IG SW V37 P S IGN STA SW V39 l SL STARTER O Starter switch GND V49 GSFGND GND V53 GSFGND P GND V51 HSGGND P GND V55 HSGGND V13 P S IGN Electronic control unit NE Vehicle speed sensor V15 l F VSS ACCP1 VCC ACCP1 ACCP1 GND V44 S S 5VREF V7 l A PPS1 V32 S R 5VRTN Pedal position sensor 1 ACCP2 VCC ACCP2 ACCP2 GND V43 S S 5VREF V6 l A PPS2 V31 S R 5VRTN Pedal position sensor 2 THA PAC VCC as PAC V5 I A A C AC pressure PAC GND V30 S R SVRTN BK2 SW V16 l SL BRAKE2 o o CL SW Brake switch 2 N C Clutch switch N C IV40 l SL GEARPOSN o O BK1 SW V3 l SL BRAKE1 OO ei Brake switch 1 N O LOIL SW I E25 1 SH LOWOIL Low oil level switch fe ee fi Gs MAF Air mass flow Se MAF GND i V29 S R 5VRTN Q000158E 27 LEGR EGR position E45 l A EGRP LEGR GND p 7 s R SVRTN A MIL 7 MIL V24 O SL DIAGLAMP I O s Fan control relay 1 o o FAN1 REL m V23 0 SL FAN1 40000 Fan con LI O O FAN2 REL El V35 0 SL FAN2 000 EGR solenoid Doma L EGR UT E48 O PL EGR VSS solenoid V47 O SL FAN3 Joint to Turbo solenoid PL Turbo V48 0 SL ACCRLY E38 1 PL 1 T Inatake valve control
21. njection pressure at all times particularly in the low engine speed range and dramatically decreases the amount of black smoke ordinarily emitted by a diesel engine during start up and acceleration As a result exhaust gas emissions are cleaner and reduced and higher power output is achieved 1 Injection pressure control e Enables high pressure injection even at low engine speeds e Optimizes control to minimize particulate matter and NOx emissions 2 Injection timing control Enables finely tuned optimized control in accordance with driving conditions 3 Injection rate control Pilot injection control sprays a small amount of fuel before the main injection Common Rail System Injection Pressure Control Injection Timing Control Injection Rate Control Optimization High pressurization Optimization Pilot injection Main injection Injection Quantity Control Cylinder injection volume correction Common rail system Common rail system njection rate O B jew F a mob B v e o g 5 D a g a c 2 5 Ki Particulate Injection timing Injection 35 pressure 2 Comparison to the Conventional System In line VE Pump Common rail system High pressure pipe Momentary high pressure Nozzle Governor In line pump T Injector Fuel tank eon aly tl Injection pressure control Engine ECU supply pump SCV 2 1 TWV Two Way Valve 2 SCV Suction Control Valve 0QD2341E 2 2
22. njection quantity timing and pressure as well as the EGR exhaust gas recirculation 3 Fuel Svstem This svstem comprises the route through which diesel fuel flows from the fuel tank to the supplv pump via the rail and is injected through the injector as well as the route through which the fuel returns to the tank via the overflow pipe 4 Control Svstem In this svstem the engine ECU controls the fuel injection svstem in accordance with the signals received from various sensors The components of this svstem can be broadiv divided into the following three tvpes 1 Sensors 2 ECU and 3 Actuators 1 Sensors Detect the engine and driving conditions and convert them into electrical signals 2 Engine ECU Performs calculations based on the electrical signals received from the sensors and sends them to the actuators in order to achieve optimal conditions 3 Actuators Operate in accordance with electrical signals received from the ECU Injection svstem con trol is undertaken by electronically controlling the actuators The injection quantity and timing are determined by controlling the duration and the timing in which the current is applied to the TWV Two Way Valve in the injector The injection pressure is determined by controlling the SCV Suction Control Valve in the supply pump Sensor Actuator Engine speed Crankshaft Position Sensor NE ee eg Injection quantity control Injection timing control Cylin
23. tart and the end of injection No injection e When no current is supplied to the solenoid the valve spring force is stronger than the hydraulic pressure in the control chamber Thus the TWV is pushed downward effectively closing the outlet orifice For this reason the hydraulic pressure in the control chamber is applied to the command piston causes the nozzle spring to compress This closes the nozzle needle and as a result fuel is not injected Injection e When the current is initially applied to the solenoid the attraction of the solenoid pulls the TWV up effectively opening the outlet orifice and allowing the fuel to flow out of the control chamber After the fuel flows out the hydraulic pressure in the control chamber decreases pulling the command piston up This causes the nozzle needle to rise and injection to start e The fuel that flows past the outlet orifice flows to the leak pipe and below the command piston The fuel that flows below the nozzle needle lifts the it upward which helps to improve the nozzle s opening and closing response e When current continues to be applied to the solenoid the nozzle reaches its maximum lift where the injection rate is also at the maximum level When current to the solenoid is turned OFF the TWV falls causing the nozzle needle to close immediately and the injection to stop l A Ji pre Actuation Actuation current l current Outlet orifice Inlet orifice td p 1 Control
24. ump which is integrated in the supply pump draws fuel from the fuel tank and feeds it to the two plungers via the fuel filter and the SCV Suction Control Valve The feed pump is driven by the drive shaft With the rotation of the inner rotor the feed pump draws fuel from its suction port and pumps it out through the discharge port This is done in accordance with the space that increases and decreases with the movement of the outer and inner rotors Quantity decrease Quantity decrease fuel discharge Outer rotor to Pump chamber Intake port Quantity increase Quantity increase fuel intake QDO708E from Fuel tank 2 SCV Suction Control Valve e A linear solenoid type valve has been adopted The ECU controls the duty ratio the length of time that the current is applied to the SCV in order to control the quantity of fuel that is supplied to the high pressure plunger e Because only the quantity of fuel that is required for achieving the target rail pressure is drawn in the drive load of the supply pump decreases e When current flows to the SCV variable electromotive force is created in accordance with the duty ratio moving the armature to the left side The armature moves the cylinder to the left side changing the opening of the fuel passage and thus regulating the fuel quantity e With the SCV OFF the return spring contracts completely opening the fuel passage and supplying fuel to the plungers Full quantity intake an
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