0302 Delphi CRDi Final

DELP DE LPHI HI CRD CRDii Fu Fuel el Sys Syste tem m

DELPH DELPHII CRDi CRDi Fuel Fuel Syste System m Part Parts s 1: General General



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DELPHI CRDi Fuel System Parts 1: General

FEEDING CIRCUIT A low pr ess ure c irc uit which feed s t he fuel equ ipm ent with pres su ris ed and fi lter ed fuel . HP CIRCUIT A hi gh pr ess ure c irc uit with an HP p ump to co mp res s th e fuel fr om th e low pres su re ci rc ui t to the rail through a high pressure pipe. A rail to ac cu mu late high ly p res su rised fuel, co nn ect ed to th e inject or s b y h igh pres su re pi pes. Electronically contro lled injectors (one per cylin der) which ensure the introduction of th e required amount of fuel at the right time in the cylinders. BACK-LEAK LP CIRCUIT A back -leak low pres su re c irc uit whi ch has t wo mai n func tions : - to coll ect the pump back-leak flow and to divert it back to the tank - to coll ect the injector back-leak flow. This function is helped by a


INLET (suction) (From f ilt er)

OUTLET (To C/rail)

INLET MEETERING VALVE (IMV)

VENTURI (For r eturn)

FUEL TEMPERATURE SENSOR


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High pr esser pump 1

Inlet Metering Valve(IMV)

2

Hydraulic Head

3

Plunger

4

Drive Shaft + Cam Ring

5

Housing

6

Roller + Shoe

7

Transfer Pressure Pump

8

Temperature Sensor

9

Venting

10

Outlet High Pressure Flange

11

Transfer Pressure Regulator

High Pressure Pump Assembly


Normal operation (make a pressure)

High pressure pump is self lubri cated from i ncomi ng fuel.


Deceleration (with out pressure)


Filtered fuel is sucked through the HP pump inlet nipple. The fuel then passes into the transfer pump which raises the inl et pressure to a level known as transfer pressure. Natural transfer pressure is a function of p ump speed. A regulator valve wh ich forms part of the housing maintains this pressure at a predetermined level (around 0.6 Bar). Fuel at tr ansfer pressure also passes int o the inlet metering valve which controls the amount of fu el delivered to the pumping element(s). The fuel enters the hydraulic head, is compressed by the plun gers and forw arded to the high pressure pipe and then to the rail. Pressures: Pump suction from tank: -100 mbar Low pressure : 6 bar (internal) High pressure: 1400 bar Back leak (return): -0.5 bar

Transfer Pressure Regulator

OUT

IN


Transfer (Feed) Pressure Regulator

OPERATING PRICIPLE A regulating valve allows the transfer pressure to be maintained at a practically constant level ( about 6 bar) throughout the whole range of engines operations by returning some of the fuel to the pump in let. Regulating valve

High Pressure Plunger of High Pressure Pump


IMV ( Inlet Metering Valve) The LP (Low Pressu re) actuator also kn ow as the IMV (inlet meterin g valve), is used to cont rol the rail pressure by regulating the amount of fuel which is sent to the pump ing element of t he HP pump. in su ch a way that the pressure measured by th e HP rail sensor i s equal to the pressure demand sent out by th e ECU. of operation i t This actuator has two p urposes. Firstly it allows the efficiency of the injection system to be impr oved, since the HP pump onl y comp resses the amoun t of fu el necessary to maitain in t he rail th e level of pressure required by the system as a funct ion o f the engines operating conditi ons.


IMV ( Inlet Metering Valve) The IMV is normally open when it is no t being suppli ed with current. It cannot therefore be used as a safety devic e to shut down the engine if r equired. The IMV is co ntroll ed by current. The flo w/curr ent law is shown below.


RAIL DESIGN The high pressure volume forwarded from t he HP pump through a HP pipe is stored in the accumulator also named the rail. It consists of a distributor manifold which provi des the fuel at the injection pressure to the injectors th rough HP pipes and damps the pressure fluctuations.

DELPHI CRDi Fuel System Parts 1: General • • • • • • • • • • • • •


Pressure sensor >> Type : diaphragm/Piezo sensor >> Power supply : 5 +/- 0.25V >> Pressure sensing range : 0 to 1800 Bar >> Maximum pressure : 2200 Bar >> Burst pressure : over 2500 Bar

5V 4.8V 4.5V

0.5V 0

1800 bar


Supply 5V Sign al 0.5~4.5V Ground 0V

5V 4.8V 4.5V

0.5V 0

1800 bar


Technology The maximum inj ector pressures are approxi mately 1600 bar. the forc es to be overcome in order to li ft the needle of the inj ector are very large. Because of th is, it is impo ssible to directly contr ol the injector by usi ng an electrom agnetic actuator, unless very hig h currents are used, which wo uld be incomp atible with the reaction times required for t he mulitple injections.


This requires bulky and expensiv e power electronics and lead to consi derable heating of the actuator and DCU. The inj ector is i ndir ectly controll ed by means of a valve contro lling the pressurisin g or discharging of the control chamber loc ated abov e the Needle: When the needle is r equired to li ft (at start o f inj ection), the valve is opened in order to di scharge the control chamber in to the return line. When the needle has to cl ose (at the end of i njection) the valve clos es again so that the pressur e is reestablished in the control chamber.


The purpose of t he injector is to inject the required amount of fuel at the right ti me with variation of i njection vol ume and start of in jection


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µ

main injection

pilot 1

pilot 2

post pilot




In order to garantee response time and mi nimu m energy con sump tio n: •

The valve must be a lig ht as possi ble

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The valve stroke must be as short as possibl e

The effort needed to mo ve the valve must be minimal, whic h means that the valve must b e in hydraulic equalibrium in the closed position. Spring pressure ensures cont act between the valve and its Seat. To lif t the valve, it is therefore requir ed to overcome the force applied by this spr ing.


The spacer is situ ated und erneath th e valve suppo rt. It intergrates the control chamber and th e three calibrated orific es which allo w operation o f the inj ector. The orif ices are: •

The injector supp ly orif ice (Nozzle Path Orifice: NPO)

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The cont rol c hamber disch arge orifice (Spil l Orifice: SPO)

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The cont rol ch asmber fill ing o rifi ce (Inlet Orifi ce Contr ol: INO)


Control valve

Adaptor plate


No current is sent to the control valve solenoi d, the cont rol valve is closed, the pressure in the cont rol ch amber is the same as in the rail, the nozzle is kept closed. The cont rol valve solenoi d is energized via the ECM, the con trol valve lifts , the fuel pressure in the needle contro l chamber starts to dro p, the nozzle is stil l clos ed. When the pressure in the cont rol chamber has drop ped suffic iently and as the fuel p ressure at the nozzle seat remains equal to th e rail pressure, the nozzle needle is unb alanced and m oves upwards.






The ECM ECM cuts th e current to t he control v alve solenoi d, the cont rol valve return return s to its seat due to the solenoi d spri ng forc e, the pressure in the needle needle contro l chamber increases increases and becomes "sl igh tly" larger than the pressure in the nozzle seat seat thus cl osin g the needle needle and and sto ppi ng the injecti on.



Injector Control The control cur rent of the injector injector c oil has the following form: Pull peak=24. peak=24.5 5 A no m Hold peak=6.8. peak=6.8.A A n om Pull tr oug h=7.4 h=7.4.A .A nom Hold tr ough =5.2 =5.2.A .A nom

The low current allo ws fo r the Joul e effect effect los ses in th e DCU DCU and inj ector to b e reduced. reduced. The The call current is higher than the hol d current because during the hold phase: phase: air g ap between between th e valve and and the coi l i s reduced (by t he valve stroke value i.e. about 30 µm and the -The air electrom electrom agnetic force to b e appl appl ied to th e valve valve can thus b e reduced. reduced. -It is no l onger necassary necassary to o vercome the valves valves inertia


Discharge Discharge through the injectors When When the rail pressure demand demand sud denly dro ps: -

Foot off the accelera accelerator tor (overrun) (overrun)

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Or duri nig a fault fault requiring the rapid di scarge of t he rail rail

Closing t he IMV IMV wil l not allo w the new requir requir ed pressure pressure defined by the DCU DCU to be reached reached quic kly enoug h. The The system therefore therefore usues the injectors t o disc harge the rail.This rail.This method i s based based upo n the response time of th e injectors. In In fact, to discharge the HP circuit w ithout risking the introducti on of fuel into the cylinders, it is necessar necessary y to suppl y the coils wit h pulses which are long enough to lif t the valve and thus bring the rail rail in to direct communiccation wi th the injectors return circuit, but short enough to prevent prevent the injector needle needle from lift ing and thus causing the unwanted introduction of fuel into the combustion chamber. chamber.


Discharge through the injectors (cont) This method of operation is only possib le if the control of the response time of t he injector is perfect, i.e. the time between the start of energizing of t he solenoi d valve and the moment at whi ch the injector n eedle lift s. This time is obviousl y diff erent for each i njector because it depends on i nitial characterist ics and amount of w ear of t he injector. It is th erefore essenti al to accurately know the initail characteristics and deviation of each injector. The inj ectors of the commo n rail sys tem are very high precision parts.They are capabel of inj ecting f low s rangin g fro m 0.5 to 100 mg/stroke at pressures of 150 to 1600 bar. Extremely high prod ucti on t olerances are required. However, due to sli ght variations in m aching, pressure drops, mechanical frict ion, and magnetic fo rce may vary between Injectors, as a result deviations u p to 5 mg/stroke can occur. This means it is im possible to effectively control an engine with such di fferences between the inj ectors. It is therefore necessary to apply a correcti on w hich wil l make it pos sibl e to in ject the required amou nt of fuel whatever the initial characterist ic of the injector, to do this , it is necessary to know the this characteristic and to co rrect the pulse applied to the injector accordi ng to t he differences between this


All inj ect ors are n umb ered into a batc h depend ing up on ther e part icu lar characterist ic, by using a data matrix code (for produ ctio n li ne) and a alphanumerical code (for aftersales service) -

If an in jector i s replaced it is n ecessary to lo ad the value into DCU

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If all inj ectors are replaced, ALL v alues must b e loaded i nto DCU

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To reset the learnt perameters whi ch ch aracterise the state in wh ich the system has pro grammed itself. Because the system is starting again w ith n ew components, it is advisable to return th ese programmings to the original values.

If a DCU is r eplaced, it is then necessary to: -

Load ALL t he values and the vehich le confi guration int o the new DCU

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To copy the learnt parameters whi ch charcterise the state in w hich t he system is in. As the DCU is new it w ill not know these values, it will therefore use neutral values. To ensur e optimu m operation f rom th e first start it i s necessary to r ecord t hese values in th e DCU.

Re-programming is explained furt her in th e Hi-Scan section.



CII for A/S

CII for production

Further details on calibration can be found in the Hi Scan sectio n


Filtration: • • • •

85% of 5µ particles 97% of 10µ particles


The filter has an internal bi -metal strip, in cold conditio ns the fuel return f rom the HP pump is directed throu gh the filter housi ng, to be mixed with new fuel going into t he HP pump. As a res ult o f fr ict ion and co mpres si on in the HP pu mp th e leak f uel temperature is rapidl y incr eased. This sysem is acting as a fuel heater. When t he fuel t emperature has reached approxim ately 40 C the bi-metal strip releases the steel ball closing the port, allowing th e return fu el to fl ow to the fuel t ank.


To Pump

Cold From Pump

To Pump

To Tank

Hot From Pump

Steel ball

Bi-metal str ip


Priming pump

Fuel heater

Fuel filter

Fuel h eater is o perated by bi-metal which is l ocated inside of fuel heater. Bi-metal is closed(switch “ on” ) when t he temperature reaches below -2 C. Bi-metal is opened(switch “ off” ) over 3 C. Specifi cation o f fu el heater - Operation voltage : battery voltage - Maximum voltage : 24V - Current : 11A - Sealing pressure : 6bars - Sealing vacuum pressure : 0.5bar - Life : 10000cycles



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ECM


Exhaust Gas Return (EGR) EGR OFF Condition •Coolant temp un der 15 C

EGR Valve

Or over 100 C •Intake air temp o ver 60 C •Engi ne RPM over 2500rpm •Engi ne load o ver 40% of Max. • A/C on • Altitud e over 1000 Meter s • Air fl ow sen so r f ault •During cranki ng (and fo r 2 secs)

Solenoid Valve

ECU is co ntroll ing a solenoid v alve to apply a vaccum to o perate the EGR. Feed back c ontrol is via the air mass senso r HFM5


Heat Exchanger Heat exch anger The heat exchanger, located at th e rear of th e cylinder head, is to co ol th e EGR gases entering the int ake manifo ld.

Cabin Heater The Terracan is not fitted with a cabin Heater for t he follo win g reasons: -Engi ne capacity i s larger than that of the `D` engi ne. -Heater in let hose di ameter has been increased. The above meets the target requir ements o f cabin warm up.

Heat exchanger


Air Intake Heater

Mainl y the ECU is mon ito ring t he coolant temperature, shoul d t he temperature Air Int ake h eater

be in th e operating range the air in take heating element/s are operated for the

Intake heater manifold

duration as listed in the followin g chart

AIH_r elays_dri ve BAT

Vbat Coolant_temperature Fuel_demand

R E L A Y 1

ECU

R E L A Y 2

Engine_cycle_speed At mosp heric _press ur e

DIAG1 IG1

DIAG2

A/HEA TER Specification: LAMP Vbatt: 14V Resistance: 0.2 Current: 70 A ( x two elements = 140 Amp s

A / H E A T E R 1

GND

A / H E A T E R 2


The air intake heating element i s controlled by the ECU, which must consider many variables as listed below: Engine_stop_request Atmospheric_pressure

ISO_AIH_Lamp_active

Battery_voltage

AIH_Relay_drive_mode

Coolant_temperature

AIH_Lamp_drive_mode

Coolant_temp_faults

AIH_Relay_faults

AIH_Diag_high1

ECM

Preheat_entry_time

AIH_Diag_high2 Engine_speed AIH_Control_ISO_request Checked_main_fuel_demand

Air heaters


Air Intake Heater (Pre & post Heating) Pre-Heating

Post-Heating

Temp °C

Time (sec)

Temp °C

Time (sec)

-30

26 sec

-20

26 sec

-25

20sec

-10

20sec

-20

15sec

0

15sec

-15

10sec

+20

10sec

-10

5.5sec

+80

5.5sec

-5

3.5sec

0

2sec

+20

0sec

During th e post heatin g tim e, Air h eating elements are swit ched on, alternating between cir cuits 1 & 2 for 10 secs. In addit ion , after startin g th e engin e RPM did not reach 3000rpm th e heater elements are continu e d to be powered for a maximu m of 180 secs.

Air Flow Sensor

Air Flow Sensor

Air flow Sensor



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It is strictly prohibi ted to supp ly an actuator d irectly off an external power supply. The inj ector must not b e dism antled. The HP sensor mu st n ot b e removed fro m th e rail. If th e HP sensor fails, It is essential to replace the complete rail. The IMV, the diesel temperature sensor and t he ventur i must n ot be removed from the pum p. If one of these comp onents is faulty, the whole pump must be replaced. The HP pipes are not reus able : a removed pip e must be replaced. Decarbonizing the injector in an ultrasonic bath is strictly prohibited. The computer’s m etal casing must never be used as an earth! During w elding j obs (bodyw ork repairs), the ECM must be carried out by qualifi ed staff who have received tr aining at the DELPHI DIESEL SYSTEMS trainin g c enter.


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High Pressure Plunger of High Pressure Pump

High Pressure Pipes

1.

4 HP pipes rail / injector

2.

1 HP pipe pump / rail

If the Injector or main rail feed pipes are removed they MUST BE REPLACED WITH NEW

During the removal of the injection system When the injection system has been opened, it is strictly prohibited to use a blower, a brush or a tube brush, since these tools might cause impurities to get into the system. As soon as an orifice has been opened, it is essential to block it using the appropriate plug. * WARING THE PLUGS MUST BE DISCARDED AFTER USE. After opening up and blocking the holes, each component of the injection system must be stored in a new sealed pouch. Cleaning of the injector is strictly forbidden, even with an ultrasonic cleaner. Moreover, the separation of the injector from the injector holder is prohibited.

During reassembly of the injection system

The packaging of the spare parts should be opened just before they are used. Moreover, the sealing plugs must not be removed until the final connection is made. The plugs and the sealed pouches must be discarded after use. Any part which has been dropped must be returned to DELPHI DIESEL SYSTEMS for assessment. Before fitting the injector, is it essential to ensure that its socket is clean.

Delphi Common Rail Cap Kit

Delphi Common Rail Cap Kit

Delphi Common Rail ECU & HP Pump

Delphi Common Rail F/Filter & Injector

Removal a rail/injector pipe(rail/HP pump) Clean the nuts of the HP unions with a solvent (CARCLEAN type) applied with a clean brush(Figure3).

1.

2. Vacuum the particles with the aid of a ‘BLOVAC BV11’ type suction device(Figure4).

3. Disconnect the injector with the aid of pliers, applying pressure to the locking clips on the side of the connector.

Removal a rail/injector pipe (rail/HP pump) Slacken the nut screwed onto the injector using a 17 mm(0.67 in) open wrench(Figure4)

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5. Slacken the nut screwed onto the rail using a 17 mm(0.67 in) open wrench(Figure 5). Notice It is important to positions the wrench level with the solid end of the nut, in order to apply the stresses to the strongest part of the nut. If the torque is applied to the open end of the nut,. There is a risk of distortion of the nut when it is tightened. Or use a pipewrench with cloth. *

Removal a rail/injector pipe (rail/HP pump) Move the nut along the pipe, keeping the olive in contract with the injector cone(Figure 6) and vacuum the particles in the contact area between the olive and the cone, using a pneumatic suction device.

6.

Carry out the same operation on the rail side.

7.

Remove the pipe and vacuum the particles inside the injector cone with the aid of the pneumatic suction device (Figure 7).

8.

Assembly a rail/injector pipe (rail/HP pump)

Assembly a rail/injector pipe (rail/HP pump) Clean pipe - Must be clean before install the pipe. 1. Incase of damaged the High pr esser Pump. - Replace commo n rail kit for th e new one. or remove and cl ean com mon rail and all the pipe. 2. Incase of change injector or maintenance system. * Self cleaning - Install the pipe on rail and tithin g the pipe olive and open other side pipe to c ontainer (Do not install other si de pipe, just r emain out s ide) - Cranking the Engine for blow out the inside of pipe using f uel fr om High presser pump.

Assembly a rail/injector pipe (rail/HP pump)

3. Fit the pipe olive into the injector cone and the rail cone. Tighten the nut by hand (Figure 10).

Assembly a rail/injector pipe (rail/HP pump) 4. Tighten the nut on the injector side to 40 Nm(29.5 lb-ft), applying reverse torque with the support tool for the injector holder (Figure 12).

* Notice When tightening the nut, ensure that the connector remains aligned with the injector row axis (Figure 13). Tighten the nut on the rail side to a torque of 40 Nm(29.5 lb-ft)

5.

ESSNTIAL To validate the repair, start the engine an check the tightness of the HP connection.

Injector holder-removal 1. Remove the HP pipe of the injector being removed (following the method indicated in refer to page). 2.

Disconnect the injector connector

Disconnect the injector leakage return hose(Figure2).

3.

Slacken off the flange of the injector holder(Figure3).

4.

Remove the injector with the flange and its bolts.

5.

0302 Delphi CRDi Final

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