SERVICE MANUAL - Service
Contents
1. 5 3 Construction and Operation z RI NINE ate 6 3 1 Description of Main Components 6 3 2 Description of Control System Components 22 3 3 Various Types of Gontrol 24 3 4 Engine ECU peg oe gana D aa 31 1 Product Application 1 1 Application Vehicle Name Engine Model Vehicle model Exhaust Volume 1 2 System Components Parts Numbers Car Manufacturer Parts Parts Name DENSO Parts Number Reference Number Supply Pump 294000 0260 8973288860 4HK1 294050 0021 9876020491 6HK1 Injector 095000 5351 8976011561 6HK1 095000 5361 8976028031 095000 5471 8973297031 4HK1 095440 0351 8973060632 4HK1 2 Outline 2 1 Outline of System e The common rail system was developed primarily to cope with exhaust gas regulations for diesel engines and aimed for 1 further improved fuel economy 2 noise reduction and 3 high power output A 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 injection pressure inje2. Same as conventional fuel injection b Pilot Injection Pilot injection is the injection of a small amount of fuel prior to the main injection Main Injection Pilot Injection Q000110E While the adoption of higher pressure fuel injection is associated with an increase in the injection rate the lag injection lag that occurs from the time fuel is injected until combustion starts cannot be reduced below a certain value As a result the quantity of fuel injected before ignition increases resulting in explosive combustion together with ignition and an in crease in the amount of NOx and noise Therefore by providing a pilot injection the initial injection rate is kept to the minimum required level dampening the explosive first period combustion and reducing NOx emissions Combustion Process Small Injection Amount Prior to Ignition High Injection Rate Pilot Injection Injection Rate Improvement Large Pre mixture Small Pre mixture NOx Noise Combustion Heat Generation mb Rate Ignition Delay Q000111E 25 F Fuel Injection Quantity Control a Starting Injection Quantity The injection quantity is determined based on the engine speed NE and water temperature while starting Starting Injection Quantity Engine Speed 2000127 b Transient Injection Quantity Correction When the changes in the accelerator opening are great during acceleration the increase in fuel volume is delay
3. PRESSURE SIG EBM1 EGR DC MOTOR 1 MAF SIGNAL EBM2 EGR DC MOTOR 2 INTAKE POSITION SIG PB GND BOOST PRESSURE GND SCVHI SCV HIGH SIDE PFUEL GND RAIL PRESSURE GND SCVHI SCV HIGH SIDE POIL GND OIL PRESSURE GND COOLANT TEMP MAF GND MAF GND ENGINE OIL TEMP INT GND INTAKE POSITION GND INTAKE AIR TEMP EGR GND EGR POSITION GND EGR U POSITION SIG G SLD CAM ANGLE GND EGR V POSITION SIG NE SLD CRANK POSITION GND EGR W POSITION SIG SCVLO SCV LOW SIDE THF1 FUEL TEMP SCVLO SCV LOW SIDE FUEL TEMP 2 42 sees TWV D INJECTOR D CYL2 CAMANGLEVB TWV B INJECTOR B CYL3 EGR POS EGR POSITION SIG DC MOTOR POIL VCC OIL PRESSURE VCC TWV C INJECTOR C CYL4 INT VCC INTAKE POSITION VCC TWV A INJECTOR A CYL1 lt NOTE gt e N A Component is not mounted circuit pattern only Note that the VCC and GND pin No A 78 for sensors are connected inside ECU 43 c 6HK1 ECU Connector Terminal Layout ECU CONNECTOR PIN ASSIGNMENT 154PIN 5 BS Bo ST ys 5 180 55 E mm SESE TEA PAGL m BS B4 a fl PEE APS APSS COM ves y al ed so eb Ab d 6HK1 Terminal Connections Deme mje poso E m sms DRE HORTON ST ERS ORUISE ENABLE A em Bas ns fase vere rap pomo p po
4. SHIELD GND EGR WPOS EGR W POSITION SIG NE SLD CRANK POSITION SHIELD GND THF1 FUEL TEMP SCVLO SCV LOW SIDE THF2 2 FUEL TEMP 2 SCVLO SCV LOW SIDE TWV D INJECTOR D 45 m Par EGR VCC EGR POSITION VCC TWV C INJECTOR C VNTPOS VCC VNT POSITION VCC TWV E INJECTOR E CAM ANGLE VB TWV A INJECTOR A lt NOTE gt e 1 case of connecting to outside wiring note that this terminal is connected to B inside ECU e 2 This terminal is unused e N A Component is not mounted circuit pattern only 46
5. pe 44 e eee o e eee BK2 SW BRAKE 2 SW SERVICE ENGINE SOON LAMP CL SW CLUTCH SW VSOUT1 4KPPM NEUTRAL SW VSOUT2 4 128KPPM EXB SW EXHAUST BRAKE SW ACCL REL A C CLUTCH RELAY FAXLE SW FRONT AXLE SW IGBC SW IGNORE BRAKE CLUTCH SW LCL SW LOW COOLANT LEVEL SW TORQUE LIMIT SW REV SW REVERSE SW CCDIS SW CAB CONTROL DISABLE SW WIF SW WATER IN FUEL SW SSPA SW SET SPEED A SW 1 POWER SSPB SW SET SPEED B SW GL REL GLOW PLUG RELAY RSET SW REMOTE SET SW PTOEN REL PTO ENGAGE RELAY RRES SW REMOTE RESUME SW STAEN REL STARTER ENABLE RELAY PTOEN SW PTO ENGAGE SW EXB REL EXHAUST BRAKE RELAY PTODIS SW PTO DISABLE SW FIDL L FAST IDLE ENGAGE LAMP PTOFB SW PTO FEEDBACK SW GLOW LAMP STA SW CRANKING REQUEST SW iue 5 COMMON1 INJECTOR POWER1 PFUEL RAIL PRESSURE SIG COMMON2 INJECTOR POWER2 PFUEL RAIL PRESSURE SIG COMMON INJECTOR POWER POIL OIL PRESSURE SIG B 6 COMMON2 INJECTOR POWER2 MAF SIGNAL EBM U EGR BRUSHLESS MOTOR U VNTPOS SIG VNT POSITION SIG EBM V EGR BRUSHLESS MOTOR V CAM ANGLE B9 EGR BRUSHLESS MOTOR W CRANK POSITION INCA GND SCVHI SCV HIGH SIDE PB GND BOOST PRESSURE GND SCVHI SCV HIGH SIDE PFUEL GND RAIL PRESSURE GND COOLANT TEMP POIL GND OIL PRESSURE GND ENGINE OIL TEMP MAF GND MAF GND INTAKE AIR TEMP VNTPOS GND VNT POSITION GND EGR UPOS EGR U POSITION SIG EGR GND EGR POSITION GND EGR VPOS EGR V POSITION SIG G SLD CAM ANGLE
6. 4 output open load ss P0205 TWV5 output open load emm P0206 TWV6 output open load 2901 EGR Brushless motor Position Sensor Signal Invalid P2902 EGR Brushless motor Performance Error 35 DTC Code Code Description P0606 CPU fault kas w s P0606 CPU fault weas P2920 Main relay diagnostics Fuel Level Sensor Circuit Performance i P0234 Boost Pressure Sensor exceeds upper limit 36 ECU External Wiring Diagram a 4HK1 Diagram 1 ae STARTER RELAY BATTERY C M REL STA SW STAEN REL M REL ECU B Q B E O GL CONT GLOW RELAY GM1 FB GM2 FB Oevers GM4 FB 1 BK1 SW gt O BK2 SW 1 CRR SW TAP DOWN E Q cRs sw 11 O PTOEN SW 1 PTOEN REL ES Lo Q PTOFB SW 4 PTO ENABLE RELAY OPTION V PTODIS SW G VB G G SLD PBOOST PB GND PFUEL VCC PFUEL PFUEL PFUEL GND APS1 VCC APS1 APS1 GND PS2 VCC APS2 PS2 GND PS3 VCC SHUTDOWN SW APS3 o 0 RSET SW RRES SW 1 SSPA SW A SSPB SW gt CCDIS SW TQLIM SW Oee 2 40 CL SW Q TQCUT SW 1 o FUEL SW 1 1 37 APS3 GND IDLUP VCC IDLUP IDLUP GND PACL VCC PACL PACL GND SP2 SP2
7. APS2 GND APS3 VCC APS3 APS3 GND PACL VCC PACL PACL GND POIL VCC POIL POIL GND THW THF1 2 THF2 THD MAF MAF GND CRANK POSITION SENSOR VEHICLE SPEED SENSOR CAM ANGLE SENSOR HALL BOOST SENSOR PRESSURE 1 In case of connecting to outside wiring note that this termonal is connected to B inside ECU 2 This terminal is unused 39 PTO ACCEL SENSOR ENGINE OIL PRESSURE SENSOR COOLANT TEMP FUEL 1 FUEL TEMP 2 ENGINE OIL TEMP INTAKE AIR TEMP Q000540E d 6HK1 Diagram 2 o REV SW oo O LOL sw Q FIDL SW COM GND AC SW LFUEL1 FUEL LEVEL 1 A C REQUEST SW AC HI PRESS SW LFUEL2 FUEL LEVEL 2 4WD SW o LCL SW WIF SW NSW IGN CRANK AIR 2SPD AXLE SENSOR STARTER R L 7 STAEN REL ELECTRIC 2SPD AXLE i CLUTCH SW SW AUTOMATC i ECU COMMON1 2SAXLE SW COMMON1 TWV A o MANUAL TWV E IGN3 TWV C COMMON2 COMMON2 PRESSUR TWV F A C RELAY LOW PRESSURE SW TWV B TWV D AIC CLUTCH Q ACCL REL 1 CLUSTER KO MIL O VSOUT1 TWISTED PAIR CAN1H O CAN1 SLD CHASSIS C vsour2 BUILDER SND CLASS2 TECH II O CLASS2 P GND P GND GND GND piAccL sw EGR VCC EGR UPOS EBM U EGR VPOS EGR VALVE EBM V DRIVE DC BRUSH LESS EGR WPOS MOTOER EBM W EGR GND IGN1 CRA
8. Code Description P0091 SCV output open Load short to GND SCV output open Load short to GND SCV coil open P1264 COMI output short to BATT TWV1 or 3 or 5 output short to P1263 COMI output short to GND P2152 COMI output open load Both TWV1 or 3 or 5 output open load P1266 COM2 output short to BATT P1265 COM2 output short to GND P2155 COM2 output open load Both TWV2 or 4 or 6 output open load P0201 TWV 1 output open load P0202 TWV2 output open load P0203 TWV3 output open load P0204 TWVA output open load P0400 EGR Duty Error P0500 Vehicle Speed Sensor Malfunction P0606 CPU fault P0606 CPU fault P0512 Starter Switch Short to BATT 32 P0686 Main relay diagnostics e 33 b 6HK1 34 DTC Code Code Description 20092 SCV output short to BATT output short to BATT SCV output short to BATT P0091 SCV output open Load short to GND SCV output open Load short to GND SCV coil open P1264 COM1 output short to BATT ld Po NN P1263 COMI output short to GND L TWV1 or 3 or 5 output short to GND P2011 COM1 output open load jas Both TWV1 or 3 or 5 output open load P1266 COM2 output short to BATT ld RN P1265 COM2 output short to GND TWV2 or 4 or 6 output short to GND P2012 COM2 output open load Al ss P0201 TWV 1 output open load kR ss P0202 TWV2 output open load kG ss P0203 TWV3 output open load ka s P0204 TWV
9. Diesel Injection Pump SERVICE MANUAL Common Rail System for ISUZU 4HK1 6HK1 Type Engine OPERATION February 2004 DENSO CORPORATION 00400056E 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 technology is being adopted in the fuel injection system This manual covers the electronic control model Common Rail system with HP3 HP4 pump for the ISUZU 4HK1 6HK1 type engines which are used to ELF and GM 560 series respectively Complex theories special 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 information TABLE OF CONTENTS 1 Product Application gt 2 2 Haw meee eae eee hea x agus ee q Baad e 1 1 1 Applications 1 1 2 System Components Parts Numbers 1 1 2 OUTING z 5 2 2er u e ere ta ane acean 2 271 Outline of System uuruuu 2 2 2 Outline of System susce iste o tup i ghi 4 2 3 Fuel System and Control System
10. Function The fuel injection quantity control function replaces the conventional governor function and controls fuel injection to achieve an optimal injection quantity based on the engine speed and the accelerator opening Fuel Injection Timing Control Function The fuel injection timing control function replaces the conventional timer function and controls the fuel injection to achieve an optimal injection timing according to the engine speed and the injection quantity Fuel Injection Pressure Control Function Rail Pressure Control Function The fuel injection pressure control function rail pressure control function uses a rail pressure sensor to measure fuel pressure and feeds this data to the ECU to control the pump discharge quantity Pressure feedback control is implemented to match the optimal quantity command quantity set according to the engine speed and the fuel injection quantity Input Signal 1 DENSO products Control Output Accelerator sensor Fuel Injection Rate Control NE Sensor Crankshaft Position Sensor Fuel Injection Quantity Control TDC Sensor Cylinder Recognition Sensor Fuel Control Computer ECU Fuel Injection Timing Control Rail Pressure Sensor 1 Fuel Injection Pressure Control Various Sensors 1 Water Temperature Sensor Fuel Temperature Sensor Atmospheric Air Atmospheric Air Temperature Pressure Sensor Q000537E 24 Fuel Injection Rate Control a Main Injection
11. GND SP1 VCC SP1 SP1 GND STARTER CUT RELAY CRANK POSITION SENSOR SPEED SENSOR CAMANGLE SENSOR HALL BOOST PRESSURE SENSOR RAIL PRESSURE SENSOR IDLE UP VOLUME PTO ACCEL SENSOR Q000538E b 4HK1 Diagram 2 AT CONTROLLER BRUSH MOTOR EGR POSITION SENSOR 1 ODIAG CLEAR SW LOL SW 1 POIL VCC POIL POIL GND THW THF1 THF2 THO THA INCA BAT MAF INCA GND MAF GND SP3 GND SP3 ATMT GND ATMT ACGL SW ACG F 1 1 TWV A TWV C COMMON2 COMMON2 TWV B TWV D ATM PRESSURE EXB SW i EBM1 EBM2 EGR VCC EGP POS EGR GND P GND P GND P GND P GND IDM1 IDM2 GND GND CASE GND 38 Q 1 EXHAUST BRAKE COOLANT TEMP FUEL TEMP INTAKE AIR TEMP EXHAUST BRAKE CUT RELAY EXHAUST BRAKE RELAY CHARGE Q000539E C 6HK1 Diagram 1 STARTER Sw IG0 SW IG1 SW u 2 GLOW RELAY POWER MAINTAIN RELAY V ENGINE BLOCK 1 B B C M REL M REL GL L FIDL L BK1 SW BK2 SW C PTOFB SW PTODIS SW poc RSET SW RRES SW RRPA SW RRPB SW CCDIS SW Q IGBC SW cL sw FAXLE SW VSS VSS VSS SLD G VB G G SLD PBOOST PB VCC PB GND PFUEL PFUEL PFUEL VCC PFUEL GND APS1 VCC APS1 APS1 GND APS2 VCC APS2
12. NK IGN3 Une AVNT POSITION SENSOR ET o Lock Accessory o Q000541E 40 ECU Connector Diagram a 4HK1 ECU Connector Terminal Layout ECU CONNECTOR PIN ASSIGNMENT 154PIN B5 COMMON Am 4 B3 comod jg POND m BA B2 pe no oo E if EERIE AA Q000542E ese A SLOWMONTORSrEEDBACIO aa Asse POWER WANTAN wer po 41 BK1 SW BRAKE 1 SW CHECK ENGINE LAMP BK2 SW BRAKE 2 SW CRM L CRUISE MAIN LAMP CL SW CLUTCH SW AT TACHO AT TACHO SHUTDOWN SW ENGINE SHUTDOWN SW SP2 GND DIAG CLEAR SW DIAG CLEAR SW CRSET L CRUISE SET LAMP EXB SW EXHAUST BRAKE SW SP2 REF SW REFRIGERATOR SW TORQUE LIMIT SW GLOW MONITOR1 FEEDBACK CCDIS SW CAB CONTROL DISABLE SW TORQUE CUT SW SSPA SW SET SPEED A SW GLOW MONITOR4 FEEDBACK SSPB SW SET SPEED B SW POWER RSET SW REMOTE SET SW GL CONT GLOW CONTOROLLER RRES SW REMOTE RESUME SW PTOEN REL PTO ENGAGE RELAY PTOEN SW PTO ENGAGE SW STAEN REL STARTER ENABLE RELAY PTODIS SW PTO DISABLE SW EXB REL EXHAUST BRAKE RELAY PTOFB SW PTO FEEDBACK SW EXHAUST BRAKE LAMP STA SW CRANKING REQUEST SW aC NE COMMON1 INJECTOR POWER1 PBOOST BOOST PRESSURE SIG COMMON2 INJECTOR POWER2 PFUEL RAIL PRESSURE SIG COMMON1 INJECTOR POWER1 PFUEL RAIL PRESSURE SIG B 6 COMMON2 INJECTOR POWER2 OIL
13. NOTE gt e There are 3 plungers for the HP4 12 Description of Supply Pump Components a Feed Pump The trochoid type feed pump 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 gt Quantity Increase Fuel Intake from Fuel Tank QD0708E b SCV Suction Control Valve Normally open type Alinear solenoid type valve has been adopted The ECU controls the duty ratio the duration in which current is applied to the SCV in order to control the quantity of fuel that is supplied to the high pressure plunger Because only the quantity of fuel that is required for achieving the target pressure is drawn in the actuating load of the supply pump decreases When current flows to the SCV variable electromotive force is created in accordance with the duty ratio moving the ar mature 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 qua
14. Q000529E Pressure Limiter Pressure Sensor Q000530E 16 b Pressure Limiter The pressure limiter opens to release the pressure if an abnormally high pressure is generated When the rail pressure reaches approximately 200 MPa 2038 kg cm it trips the pressure limiter the valve opens When the pressure drops to approximately 50 MPa 509 5 kg cm the pressure limiter returns to its normal state the valve closes in order to maintain the proper pressure 4HK1 200 9 MPa 2038 92 kg cm 6HK1 221 9 MPa 2254 92 kg cm Valve Open 50 MPa 509 5 kg cm Q000531E c Pressure Sensor The rail pressure sensor Pc sensor is attached to the rail in order to detect the fuel pressure tis a semiconductor type pressure sensor that utilizes the characteristics of silicon whereby the electrical resistance changes when pressure is applied to it Vc Vout GND 200 MPa 2038 kg cm Q000532E lt NOTE gt e Itis necessary to reset the ECU default value using the ISUZU diagnosis tool at the time of supply pump service replace ment In addition the ECU has a function enabling it to learn the performance of the supply pump at the time of ECU service replacement so ensure sufficient time several minutes is available 17 d Flow Damper The flow dampers are installed at the outlet of rail to damp a pulsation of fuel pressure inside the rail or to cut off the
15. Temperature Sensor The two plungers for HP3 or the three plungers for HP4 are positioned vertically on the outer ring cam for compactness The engine drives the supply pump at a ratio of 1 1 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 6 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 Intake Pressure Injector Discharge take Valve lt Feed Pressure High Pressure Return Pressure Regulating Valve Feed Pump Fuel Inlet Fuel Tank Fuel Filter with Priming Pump Development HP3 Eve 8 Ring ME E Valve lt gt 2 ENS 11 9 P003 Drive Shaft Filter Development HP4 XS 2 7 Feed Pump Ring Cam A vA 1 Regulating Valve Z TOS y 700 Drive Shaft 02 Q000528E b Supply Pump Internal Fuel Flow The fuel that is drawn from the fuel tank passes through the route in the supply pump as illustrated and is fed into the rail Supply Pump Interior Regulating Valve Feed Pump SCV Suction Control Valve Pumping Por
16. ction rate and injection tim ing the injection system is unaffected by the engine speed or load This ensures a stable injection pressure at all times particularly in the low engine speed range and dramatically decreas es the amount of black smoke ordinarily emitted by a diesel engine during start up and acceleration As aresult exhaust gas emissions are cleaner and reduced and higher power output is achieved a Injection Pressure Control Enables high pressure injection even at low engine speeds Optimizes control to minimize particulate matter and NOx emissions b Injection Timing Control Enables finely tuned optimized control in accordance with driving conditions c 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 Common Rail System Common Rail System Main injection E Crankshaft Angle Injection Quantity Control Cylinder Injection Volume Correction e 5 n 9 i Q 5 i Particulate Injection Timing Injection _ Pressure d EGR Exhaust Gas Recirculation Control By recirculating the exhaust gas into the intake side of the engine the combustion temperature is reduced and NOx is decreased Comparison to the Conventional System In line VE Pump C
17. e Sensor THL The fuel temperature sensor detects the fuel temperature and outputs it to the ECU The sensor uses a thermistor which varies resistance according to temperature As the ECU applies voltage to the thermistor it uses a voltage resulting from the division of the computer internal resis tance and the thermistor resistance to detect the temperature Output Voltage THL 40 20 0 20 40 60 80 100 120 40 4 32 68 104 140 176 212 248 F Fuel Temperature Q000106E 22 b Atmospheric Air Pressure Sensor Built in ECU This sensor converts the atmospheric air pressure into an electrical signal to correct full load injection volume Output Voltage V 38 107 1 09 Atmospheric Air Pressure kPa kg cm Q000278E 23 3 3 Various Types of Control This system controls the fuel injection quantity and injection timing more optimally than the mechanical governor or timer used in conventional injection pumps For system control the ECU makes the necessary calculations based on signals received from sensors located in the engine and on the vehicle in order to control the timing and duration in which current is applied to the injectors thus re alizing optimal injection timing Fuel Injection Rate Control Function The fuel injection rate control function controls the ratio of the quantity of fuel that is injected through the nozzle hole during a specified period Fuel Injection Quantity Control
18. ed to inhibit the discharge of black smoke Injection Quantity Change in Accelerator Opening Injection Quantity after Correction Delay Time Q000128E c Basic Injection Quantity This quantity is determined in accordance with the engine speed NE and the accelerator opening Increasing the accelerator opening while the engine speed remains constant causes the injection quantity to increase Basic Injection Quantity Accelerator Opening Engine Speed Q000129E 26 d Injection Quantity for Maximum Speed Setting The injection quantity is regulated by a value that is determined in accordance with the engine speed Injection Quantity for Maximum Speed Setting e Maximum Injection Quantity Engine Speed Q000130E Is determined in accordance with the engine speed and corrected by the coolant temperature signal Basic Maximum Injection Quantity f Amount of Injection Quantity Intake Pressure Correction Engine Speed Q000131E Limits the maximum injection quantity in accordance with the intake pressure in order to minimize the discharge of smoke when the intake air pressure is low Amount of Intake Air Pressure Correction 27 Engine Speed g Amount of Injection Quantity by Atmospheric Air Pressure Correction With using atmospheric air pressure sensor signal the maximum injection quantity curve is corrected as shown in the figure below Amount of Atmosph
19. edure Changes Differences in comparison with the conventional method of replacing injectors assembly as shown below lt NOTE gt e When replacing injectors with QR codes or the engine ECU it is necessary to record the ID codes QR codes the ECU If the ID codes of the installed injector are not registered correctly engine failure such as rough idling and noise will result New Injector with QR Codes 30 base 16 characters noting fuel injection quantity correction information displaed for market service use ID Code Q000535E 20 Replacing the Injector No correction resistance so no electrical recognition capability Spare Injector Necessary to record the injector ID codes in Engine ECU QD1536E Replacing the Engine ECU No correction resistance so no electrical recognition capability m Spare Engine ECU Necessary to record the injector ID codes in the engine ECU QD1537E Vehicle side Injector I EV E Engine ECU Electronic Control Unit a Outline This is the command center that controls the fuel injection system and engine operation in general Outline Diagram Sensor Engine ECU Actuator el Calculation mmp Actuation 21 3 2 Description of Control System Components A Engine Control System Diagram Intake Air Temperature Sensor Intake Air Pressure Sensor VNT Controller VNT Actuator Coolant Q000536E a Fuel Temperatur
20. eric Air Pressure Correction Engine Speed Q000134E h Idle Speed Control System ISC Controls the idle speed by regulating the injection quantity in order to match the target speed which has been calculated by the computer with the actual speed The functions of the ISC can be broadly divided into the following two items 1 Auto ISC Controls the idle speed in accordance with the water temperature Target Speed Water Temperature Q000135E 2 Manual ISC Controls the idle speed in accordance with the idle speed indicated on the manual idle setting knob provided at the driv er s seat Target Speed ISC Knob Terminal Voltage Q000136E 28 3 Air Conditioner Idle up Control When the conditions shown in the chart on the right are realized bring the idle up speed to constant rpm Conditions Air Conditioning SW Clutch SW ON Clutch Connection Neutral SW ON Neutral Q000137E i Auto Cruise Control Controls the actual vehicle speed by regulating the injection quantity in order to match the target speed that has been calculated by the computer with the actual speed The CRS ECU controls the injection quantity in accordance with signals from the cruise control computer 29 Fuel Injection Timing Control The characteristics of the fuel injection timing vary depending on whether it is the main injection or the pilot injection Although either the NE sensor or the auxil
21. fuel supply when the fuel leaks in the downstream of flow damper The fuel is supplied to the injectors through an orifice of the piston The pressure pulsation occurring in the rail is damped by a resistive force of the return spring 5 anda passing resistance of the orifice 2 wherein the piston 4 acts as a damper Refer to the picture B Also the leading end of piston 4 closes an fuel supply port to cut off the fuel supply if the fuel leak occurs in the injection pipe or injectors and the fuel pressure on the downstream side of flow damper supplied through an orifice 2 resistive force of return spring 5 do not balance with the fuel pressure applied on the piston 4 surface prior to the orifice 2 Refer to the picture C The piston 4 will return when the fuel pressure inside the rail less than 1 0 MPa 10 2 kgf cm 4 Piston 6 Housing 2 Orifice 3 Slit 5 Return Spring 1 From Rail 7 To Injector gt gt 18 D Injector G2 Type a 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 b Characteristics A compact energy saving solenoid control type TWV Two Way Valve injector has been adopted codes displaying various injector characte
22. gine ECU and c Actuators a Sensors Detect the engine and driving conditions and convert them into electrical signals b 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 Actuators Operate in accordance with electrical signals received from the ECU Injection system control is undertaken by electron ically controlling the actuators The injection quantity and timing are determined by controlling the length of time 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 1 DENSO products Actuator Engine Speed Crankshaft Position Sensor ww by other manufactures ylider Recognition Sensor g Injection Quantity Control Injection Timing Control Engine Load Accelerator Position Sensor ECU Rail Pressure Sensor 1 ammm Injection Pressure Control Supply Pump SCV EGR Engine Warning Light Other Sensors and Switches Construction and Operation 3 1 Description of Main Components Supply Pump HP3 HP4 a Outline The supply pump consists primarily of the pump body cam shaft ring cam and plungers SCV Suction Control Valve fuel temperature sensor and feed pump Fuel Temperature Sensor Fuel
23. iary NE sensor is the reference for controlling the injection timing the NE sen sor is ordinarily used for this purpose a Main Injection Timing The basic injection timing is calculated in accordance with the final injection quantity the engine speed and the water temperature with map correction While starting it is calculated in accordance with the water temperature and the engine speed Basic Injection Timing Final Injection Quantity Engine Speed Q000138E b Pilot Injection timing Pilot Interval The pilot injection timing is controlled by adding the pilot interval to the main injection timing Thepilot interval is calculated in accordance with the final injection quantity the engine speed and the water temperature with map correction While starting it is calculated in accordance with the water temperature and the engine speed Pilot Interval Final Injection Quantity Engine Speed Q000139E c Fuel Injection Pressure A value is calculated as determined in accordance with the final injection quantity and the engine speed While starting it is calculated in accordance with the water temperature and the engine speed Rail Pressure Final Injection Quantity Engine Speed Q000140E 30 3 4 Engine ECU A Diagnosis Codes 4HK1 I P0340 Cam Sensor No Pulse P0092 SCV output short to BATT SCV output short to BATT 31 DTC Code
24. ntity With the SCV OFF the return spring contracts completely opening the fuel passage and supplying fuel to the plungers Full quantity intake and full quantity discharge When the SCV is ON the force of the return spring moves the cylinder to the right closing the fuel passage normally opened By turning the SCV ON OFF fuel is supplied in an amount corresponding to the actuation duty ratio and fuel is dis charged by the plungers Exterior View of SCV Cross section of SCV Return Spring Pump Body Cylinder Q000270E 1 In case of short time ON duty 13 Short time ON duty gt large valve opening gt maximum intake quantity Es 2 In case of long time ON duty Long time ON duty gt small valve opening gt minimum intake quantity SC Cylinder Small Opening Cylinder Outline Stores pressurized fuel 0 to 160 MPa 0 to 1631 6 kg cm 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 The rail pressure sensor Pc sensor detects the fuel pressure in the rail and sends a signal to the engine ECU the pres sure limiter prevents the rail pressure from being abnormally high This ensures optimum combustion and reduces com bustion noise For 4HK1 Pressure Sensor Pressure Limiter
25. ommon Rail System High pressure Pipe Momentary High Pressure Nozzle Governor In line Pump Jo Injector Fuel Tank njection Quantity Control Engine ECU Injector TWV Engine ECU Injector TWV Engine ECU Supply Pump Engine ECU Rai Injection Pressure Control Dependent upon Speed and Injection Quantity Engine ECU Supply Pump SCV 1 TWV Two Way Valve 2 SCV Suction Control Valve 902341 2 2 Outline of System A Composition The common rail system consists primarily of a supply pump rail injectors and engine ECU a 4HK1 Fuel temperature sensor Vehicle speed gt Accelerator opening Intake air pressure Intake air BE Engine ECU Coolant temperature Crankshaft position Cylinder recognition sensor X Intake airflow rate EN JL a Lg A limiter Rail pressure sensor Fuel temperature sensor Supply pump SCV suction Fuel tank control valve b 6HK1 Fuel temperature sensor G Vehicle speed gt Accelerator opening Q Intake air pressure Intake air Bune Engine ECU Coolant temperature a Crankshaft position gt Cylinder recognition sensor Intake airflow rate Rail pressure sensor Fuel temperature sensor Supply pum SCV suction PERPE control valve Fuel tank Operation a Supply pump HP3 HP4 The supply pump draws fuel from the fuel tank and pumps the high pres
26. ristics and the ID codes showing these in numeric form 30 base 16 acters are engraved on the injector head The 4HK1 6HK1 engine common rail system optimizes injection volume con trol using this information When an injector is newly installed in a vehicle it is necessary to enter the ID codes in the engine ECU using the ISUZU Diagnostic tool c Construction QR Codes 30 base 16 characters Solenoid Valve Pressurized Fuel from Rail Command Piston Nozzle Spring Pressure Pin Nozzle Needle Q000533E 19 d QR Codes In order to minimize performance tolerance of injectors at replacing them QR 1 Quick Response codes have been adopted to enhance correction precision Using QR codes has resulted a substantial increase in the number of fuel injection quantity correction points and thus the injection quantity control precision has improved The characteristics of the engine cylinders have been further uni fied contributing to improvements in combustion efficiency reductions in exhaust gas emissions and so on lt NOTE gt e QR code correction points Injection quantity Q Pressure Parameter QR code on the injector connector Actuating pulse width TQ Q000670E e Location of QR codes QR Codes 8 9mm ID Codes 30 alphanumeric figures Base 16 characters noting fuel injection quantity correction information for market service use Q000534E e Repair Proc
27. sure fuel to the rail The quantity of fuel dis charged 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 b The rail is mounted between the supply pump and the injector and stores the high pressure fuel c Injector G2 type This injector replaces the conventional injection nozzle and achieves optimal injection by effecting 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 determines the quantity rate and timing of the fuel that is injected from the injector d Engine ECU The engine ECU calculates data received from the sensors to comprehensively control the injection quantity timing and pressure as well as the EGR exhaust gas recirculation 2 3 Fuel System and Control System A Fuel System This system comprises the route through which diesel fuel flows from the fuel tank to the supply 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 B Control System In this system the engine ECU controls the fuel injection system in accordance with the signals received from various sensors The components of this system can be broadly divided into the following three types a Sensors b En
28. tion Plunger Intake Valve Fuel Tank Q000283E c Construction of Supply Pump in case of HP3 pump The eccentric cam is attached to the cam shaft The eccentric cam is connected to the ring cam Cam Shaft Eccentric Cam Ring Cam QD0706E As the cam shaft rotates the eccentric cam rotates eccentrically and the ring cam moves up and down while rotating 10 The plunger and the suction valve are attached to the ring cam The feed pump is connected to the rear of the cam shaft Feed Pump 11 d Operation of the Supply Pump As shown in the illustration below in case of HP3 pump 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 Asa result Plunger B draws in fuel while Plunger A pumps it to the In the case of the 4 cylinder engine used with the HP3 pump each plunger pumps fuel in a reciprocal movement during the 360 cam rotation Conversely in the case of the 6 cylinder engine used with the HP4 pump 3 plungers pump fuel in a reciprocal movement for each one rotation of the cam Delivery Valve Eccentric Cam SCV Plunger B 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 QD0707E lt
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