-1

June, 2003

Diesel Injection Pump

Common Rail System for HINO

Operation

No. E-03-03

SERVICE MANUAL

J08C/J05C Type Engine

00400024

For DENSO Authorized ECD Service Dealer Only

0

GENERALThe ECD-U2 was designed for electronic control of injection quantity, injection timing and in-jection pressure to obtain optimal operational control.

Features• Lower exhaust gas and higher output due to high pressure injection in all usage ranges.• Reduction in noise and exhaust gas due to injection rate control.• Improved performance due to increased flexibility in the injection timing setting.• Independent control of injection pressure in response to engine speed and load.

Main Elements

Main Components Part Number

Manufacturer Vehicle Model

Engine Model

Cylinder Configuration

Total Displacement

(cc)Maximum Output

(PS/rpm)

Hino Motor, Ltd.HR1J J08C Straight 6 7,961

J-N: 205/2,900J-V: 220/2,900

RX4JFE J05C Straight 4 5,307 175/2,900

No. DescriptionHR1J (J08C-UC) RX4JFE (J05C-TG)

DENSO P/N HINO P/N DENSO P/N HINO P/N1 Supply pump 094000-0183 22730-1042A 094000-0193 22730-1072A

1-1 Cylinder recognition sensor 029600-0580 89411-1290A1 029600-0580 89411-1290A1

2 Injector 095000-0174 23910-10033C 095000-0174 23910-10033C3 Rail 095440-0243 22760-1100C 095440-0171 22760-1041C

3-1 Rail pressure sensor 499000-4441 — 499000-4441 —3-2 Pressure limiter 095420-0060 — 095420-0060 —3-3 Flow damper 095400-0150 — 095400-0150 —

1

1. Outline1.1 System OutlineThis system also provides the following functions:

• A self-diagnosis and alarm function using computer to diagnose the system’s majorcomponents and alert the driver in the event of a problem.

• A fail-safe function to stop the engine, depending upon the location of the problem.• A backup function to change the fuel regulation method, thus enabling the vehicle to

continue operation.1.2 System ConfigurationDivided by function, the system can be classified according to the fuel system and the controlsystem.[1] Fuel SystemHigh-pressure fuel that is generated by the supply pump is distributed to the cylinders using a rail.Electromagnetic valves in the injectors then open and close the nozzle needle valve to controlthe start and end of fuel injection.

[2] Control SystemBased on the signals received from various sensors mounted on the engine and the vehicle, theECU controls current timing and the duration in which the current is applied to the injectors, thusensuring an optimal amount of fuel is injected at an optimal time.The control system can be broadly classified according to the following electronic components:sensors, computers, and actuators.

Fuel tank Supply pump Rail

Electronic

control

Injector

Discharge

volume

Solenoid valve to control

the needle lift

Q000080E

Sensors Computers Actuators

Accelerator sensorInjectors

Rail

Supply pumpOther sensors and switches

NE sensor

(Crankshaft position sensor)

TDC sensor

(Cylinder recognition sensor)

(Accelerator opening)

(Engine speed)

Cylinder

recognition signal

Fuel injection quantity

and injection timing control etc.

(Fuel pressure control)

ECU( )

( )

Q000081E

2

[3] System Configuration (1)

Q000089E

Signals fromswitches

ACCP,ACCSW

Accelerator positionsensor

ECU

Charge-upcircuit

Starter signal

Air cleaner

Water temp. sensor

THW THL

STA

Fuel temp.sensor

Leak pipe

Flow damper

NE sensorTDC sensor

Fuel filiter Fuel tank

Supplypump

Pressure limiter

Rail

3

[4] System Configuration (2)

Q000115E

Fu

el

Inje

ctio

n

·In

jectio

n Q

ua

ntity

Co

ntr

ol

·In

jectio

n T

imim

g C

on

tro

l

·In

jectio

n P

ressu

re C

on

tro

l

En

gin

eV

eh

icle

·A/T

Co

ntr

ol

·Exh

au

st B

rea

k C

on

tro

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·En

gin

e S

hu

t-d

ow

n c

on

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·DS

T-1

CO

MM

UN

ICA

TIO

N

Co

mm

un

ica

tio

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Se

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e T

oo

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(Sca

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(De

ale

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Ra

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ressu

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en

so

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Flo

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am

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Inje

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Ra

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Pre

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NE

Se

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Bo

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ressu

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en

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Acce

lera

tor

Po

sitio

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so

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(in

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CU

)

· Co

ola

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pe

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Air T

em

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sor

TD

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Cylin

de

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Se

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up

ply

Pu

mp

Inje

ctio

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ate

Co

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ol

Inje

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n Q

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Co

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Inje

ctio

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(Pre

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DS

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Atm

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Pre

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4

1.3 Construction and Operation of the SystemThe rail system is comprised of a supply pump, a rail, and injectors, and also includes an ECUand sensors to regulate those components.The supply pump generates the internal fuel pressure in the rail. Fuel pressure is regulated bythe quantity of fuel discharged by the supply pump. In turn, the fuel discharge quantity is regu-lated by electronic signals from the ECU that turn the PCVs (pump control valves) ON and OFF.Upon receiving fuel pressurized by the supply pump, the rail distributes the fuel to the cylinders.The pressurized fuel is detected by the rail pressure sensor (installed in the rail) and undergoesfeedback control so that actual pressure will match the command pressure (designated accord-ing to the engine speed and load).Pressurized fuel in the rail passes through the injection pipes that lead to the cylinders, and appliespressure to the injector nozzles and the control chamber.The injector regulates injection quantity and timing by turning the TWV (two-way valve) ON and OFF.When the TWV is ON (current applied), the fuel circuit switches over, causing the high-pressurefuel in the control chamber to flow out via the orifice. As a result, the force of the high-pressurefuel at the nozzle valve opening causes the needle valve to lift, thus starting the injection of fuel.When the TWV is turned OFF (current not applied), the fuel circuit switches over so that high-pressure fuel, traveling via the orifice, is introduced to the control chamber. As a result, the nee-dle valve lowers, thus ending the injection of fuel.Thus, through electronic control, the timing of the current applied to the TWV determines theinjection timing, and the duration in which current is applied to the TWV determines the injectionquantity.

Q000084E

Additional information(temperature, pressure)

Engine load

ECU

Supply Pump

· Injection volume control

· Injection timing control

· Injection rate control

TWV

Leak

Orifice

Control chamber

Hydraulic piston

Nozzle

Needle

Injector

TWV control pulse

Rail pressure sensor

Rail

Injection pressurecontrol

5

1.4 Comparison to Conventional Pump

Inline Type Common Rail System

System

Injection quantity regulation

Injection timing regulation

Distribution of generated pressure

Distribution

Injection pressure regulation

Pump (governor)

Pump (timer)

Pump

Pump

(Dependent on engine speed and injection volume)

ECU, injector (TWV)

ECU, injector (TWV)

Supply pump

Supply pump (PCV)

Rail

Q000085E

Pipe

Instantaneous highpressure

Timer

Pump

GovernorNozzle

Supply pump

Rail

Constant highpressure

Injector

6

2. Construction and Operation of Components2.1 Supply Pump[1] OutlineThe function of the supply pump is to regulate the fuel discharge volume, thus generating internalfuel pressure in the rail.[2] ConstructionThe supply pump consists of a feed pump, similar to that of the conventional in-line pump, andthe PCVs (pump control valves), provided at each cylinder, to regulate the fuel discharge volume.The supply pump uses a three-lobe cam or two-lobe cam reducing the number of pump cylin-ders to one-third or one-second of the engine cylinders (e.g. a two-cylinder pump for a six-cyl-inder engine or for a four-cylinder engine). Furthermore, a smooth and stable rail pressure isobtained because the rate at which fuel is pumped to the rail is the same as the injection rate.

Q000116E

3-lobe cam

PCV (Pump Control Valve)

Gear of cuxiliary NE sensorFeed pump 2-lobe cam

for J08C for J05C

7

[3] Operation A: The PCV remains open during the plunger’s downward stroke, allowing low-pressure fuel to

be drawn into the plunger chamber by way of the PCV. B: If the valve remains open because current is not applied to the PCV, even after the plunger

begins its upward stroke, the fuel that was drawn in returns via the PCV, without being pres-surized.

C: When current is applied to the PCV in order to close the valve at the timing that accommo-dates the required discharge volume, the return passage closes, causing pressure in theplunger chamber to rise. The fuel then passes through the delivery valve (check valve) to therail. As a result, an amount of fuel that corresponding to the plunger lift after the PCV closesbecomes the discharge volume, and varying the timing of the PCV closure (plunger pre-stroke) varies the discharge volume, thus regulating rail pressure.

A’: After surpassing the maximum cam lift, the plunger begins its downward stroke, causingpressure in the plunger chamber to decrease. At this time, the delivery valve closes, thusstopping the pumping of the fuel. In addition, because current to the PCV valve is cut off, thePCV opens, allowing low-pressure fuel to be drawn into the plunger chamber. Thus, thepump assumes condition “A”.

Q000087E

Suction process Delivery process

Cam lift

Valve open

Pre-stroke

PCVoperation

Valveclosed

Hh

Increasingdischargevolume

Reducing discharge volume

Discharging requireddischrge volume

Common rail

Pump operation

PCV

Plunger

Delivery valve

A B C A'

φd

Dischargevolume Q=

πd2 (H-h)

4

8

[4] PCV (pump control valve)The PCV regulates the volume of fuel discharged by the supply pump in order to regulate railpressure. The volume of fuel discharged by the supply pump to the rail is determined by thetime at which current is applied to the PCV.

[5] Trochoid Type Feed PumpThe feed pump, which is housed in the supply pump, draws fuel up from the tank and deliversit to the chamber via the fuel filter. The feed pump rotor is driven by the camshaft.The rotation of the camshaft causes the outer and inner rotors to rotate. At this time, the suctionport side pump chamber volume (the space surrounded by the outer and inner rotors) increasesgradually, causing the fuel entering from the fuel inlet to be drawn into the pump chamber viathe suction port. Along with the rotation of the rotor, the fuel that has been drawn in moves to-wards the discharge port and is discharged. The discharged fuel travels via the fuel outlet andis fed into the supply pump body.

[6] CouplingThe coupling is an intermediary device that transmitsthe engine driving torque to the supply pump camshaft.

Key switchPCV relay

+B

PCV1

PCV2

Q000088E

ECU

PCV

Q000090E

Outer rotor To pump chamber

Inner rotor

Discharge portFrom fuel tank

Suctionport

Volume decreased(while moving to discharge port)

Volume increased(while drawing in fiel)

Volume increased(while drawing in fiel)

Volume decreased(while discharging fuel to discharge port)

Coupling

Q000091E

9

2.2 Rail[1] ConstructionThe functionof the rail is to distribute the high-pressure fuel pressurized by the supply pump toeach cylinder injector.The rail pressure sensor, flow damper, and pressure limiter are mounted on the rail.A fuel injection pipe is attached to the flow damper to deliver high-pressure fuel to the injector.The pressure limiter piping is routed back to the fuel tank.

[2] Flow DamperThe flow damper reduces pressure pulsation in thehigh-pressure pipe, thus delivering fuel to the injectorsat a stable pressure. Furthermore, in the event an ex-cessive flow of fuel, the flow damper shuts off the fuelpassage, thus preventing the abnormal fuel flow.When abnormal amount of fuel flows the high-pres-sure is applied to the piston. As shown in the illustra-tion, this causes the piston and ball to move right, untilthe ball reaches the seat and closes the fuel passage.

[3] Pressure LimiterThe function of the pressure limiter is to dispel abnormallyhigh pressure by opening its valve to release pressure.The pressure limiter operates (opens the valve) whenrail pressure reaches approximately 140MPa.Then, when the pressure decreases to approximately30MPa, the pressure limiter resumes (closes the valve)its function to maintain pressure.

NOTE:Do not attempt to remove or to reinstall the flow damper, pressure limiter, and the railpressure sensor.

Q000117E

Flow damper

Pressure limiter

Pail pressuresensor

Rail

Flow damper

Rail

Pressure limiter

Pail pressuresensor

for J08C for J05C

Q000093E

Piston Ball Seat

Stopped

During damping

During abnormal flow such asexcessive injection volume

Pc

Q000094E

10

[4] Rail Pressure SensorThe rail, the rail pressure sensor is mounted on the rail and detects the fuel pressure. It is asemi-conductor type of pressure sensor that utilizes the properties of silicon to change its elec-trical resistance when pressure is applied.

2.3 Injector[1] OutlineThe function of the injector is to inject high-pressure fuel from the rail into the engine combus-tion chamber at the proper timing, quantity, ratio, and atomization, in accordance with signalsfrom the ECU.The TWV (two-way solenoid valve) regulates pressure in the control chamber in order to controlthe beginning and end of injection.The orifice restrains the opening speed of the nozzle valve to regulate the injection ratio.The command piston transmits pressure from the control chamber to the nozzle needle valve.The nozzle atomizes the fuel.

0

1

2

3

4

5

50 100 150

VPC

A-VCC

ECU

VPC

A-GND

+5V

Pressure PC (MPa)

Ou

tpu

t vo

lta

ge

(V

)

Q000095E

Q000096E

Start of Injection (TWV ON) End of Injection (TWV OFF)

ECU

Rail pressure sensor

Rail

Supply pump

Injection pressurecontrol

Leak

TWV

Orifice

Control chamber

Command piston

Nozzle

ECU

Rail pressure sensor

Rail

Supply pump

Injection pressurecontrol

Leak

TWV

Orifice

Control chamber

Command piston

Nozzle

11

[2] ConstructionThe injector consists of the nozzle portion (similar to that of the conventional type), the orifice(which regulates the injection ratio), the command piston, and the two-way solenoid valve(TWV).

Q000118E

Upper body

O-ring

Control chamber

Orifice 2

Orifice 1

Command piston

Lower body

Guide bushing

Valve opening pressureadjustment shim

Tip packing

Nozzle

Retaining nut

Plastic cover

Linkage joint bolt

Gasket

Outlet connector

Steel washer

Inlet connector

TWV

Filter

Nozzle spring

Pressure pin

12

[3] OperationThe TWV portion of the injector consists of two valves, an inner valve (fixed) and an outer valve(movable). Both valves are precision-fitted on the same axis. The valves respectively form innerand outer seats, and either of the seats opens selectively depending upon whether the TWV isON or OFF.a. No Injection

When no current is applied to the solenoid, the valve spring and hydraulic pressure forcespush the outer valve downward, causing the outer seat to remain closed. Because the railhigh pressure is applied to the control chamber via the orifices, the nozzle remains closedwithout injecting fuel.

b. Begin InjectionWhen current is applied to the TWV, the solenoid force pulls the outer valve upward, causingthe outer seat to open. As a result, fuel from the control chamber flows out via the orifice, causing the needle to liftand fuel to start injection. Furthermore, the injection ratio increases gradually in accordancewith the movement of the orifice. As the application of current continues to apply, the injectorreaches its maximum injection ratio.

c. End InjectionWhen current to the TWV is cut off, the valve spring and hydraulic force (fuel pressure) causethe outer valve to descend and the outer seat closes. At this time, high-pressure fuel from therail is immediately introduced into the control chamber, causing the nozzle to close suddenly.As a result, injection ends swiftly.

Q000098E

Inner valve

Outer valve

Outer seat

Orifice 2

Orifice 1

Command piston

Nozzle

Rail(constant high pressure)25-120 MPa

Control chamber

No Injection Begin Injection End Injection

13

[4] Circuit Diagram

TWV #1(No. 1 cylinder)

COMMON2

COMMON1

ECU

Constant currentcircuit

Constant currentcircuit

Charging circuit

Q000119E

TWV #2(No. 4 cylinder)

TWV #3(No. 2 cylinder)

TWV #4(No. 6 cylinder)

TWV #5(No. 3 cylinder)

TWV #6(No. 5 cylinder)

for J08C

14

WARNING:High voltage is applied to the wires connected to COMMON1, COMMON2, and the TWV#1-#6 terminals of the ECU. Exercise extreme caution to prevent electric shock.

COMMON2

COMMON1

ECU

Constant currentcircuit

Constant currentcircuit

Charging circuit

Q000120E

TWV #1(No. 1 cylinder)

TWV #2(No. 4 cylinder)

TWV #3(No. 3 cylinder)

TWV #4(No. 2 cylinder)

for J05C

15

2.4 Sensors and Relays[1] NE Sensor (crankshaft position sensor)When the signal holes on the flywheel move past thesensor, the magnetic line of force passing through thecoil changes, generating alternating voltage.The signal holes are located on the flywheel at 7.5-degreeintervals. There are a total of 45 holes, with holes missingin three places. Therefore, every two revolutions of theengine outputs 90 pulses.This signal is used to detect the engine speed and thecrankshaft position in 7.5-degree intervals.[2] TDC sensor (cylinder recognition sensor)Similar to the NE sensor, the sensor utilizes the alternatingvoltage generated by the changes in the magnetic line offorce passing through the coil.The disc-shaped gear located in the center of the supplypump camshaft has a cog (U-shaped cutout) at 120-degreeintervals, plus one tooth in an additional location. Accord-ingly, every two revolutions of the engine outputs sevenpulses. The combination of the NE pulse, auxiliary pulse isrecognized as the No. 1 cylinder reference pulse.

A combination of the NE pulse and the TDC pulses areused for the cylinder reference pulse, and the irregularpulse is used to determine the No. 1 cylinder.

NE (crankshaft angle) sensor

Q000100E

TDC (cylinder recognition) sensor

Q000121E

Input circuit

TDC

NE

ECU

Input circuit

Q000122E

for J08C

Input circuit

TDC

NE

ECU

Input circuit

Q000123E

for J05C

16

No.6 cylinder TDC reference pulse

No.1 cylinder recognition pulse

No.1 cylinder TDC reference pulse

No.1 cylinder NE reference pulse No.6 cylinder NE reference pulse

0°CR 120°CR 240°CR 360°CR 480°CR 600°CR 720°CR

TDC pulse

NE pulse0 2 4 6 8 10 12 14 0 2 4 6 8 10 12 14 0 2 4 6 8 10 12 0 2 4 6 8 10 12 14 0 2 4 6 8 10 12 14 0 2 4 6 8 10 12 0 2 4 6 8

Q000124E

75°CR 75°CR 75°CR 75°CR 75°CR 75°CR 75°CR

105°CR

#1 TDC #4 TDC #2 TDC #6 TDC #3 TDC #5 TDC #1 TDC

for J08C

No.1 cylinder recognition pulse

No.1 cylinder TDC reference pulseNo.4 cylinder TDC reference pulse

Q000125E

135°CR 135°CR 135°CR 135°CR

165°CR

#1 TDC #4 TDC #3 TDC #2 TDC #1 TDC

No.1 cylinder NE reference pulse No.4 cylinder NE reference pulse

0°CR 180°CR 360°CR 540°CR 720°CR

TDC pulse

NE pulse0 2 4 6 8 10 12 14 0 2 4 6 8 10 12 14 0 2 4 6 8 10 12 0 2 4 6 8 10 12 14 0 2 4 6 8 10 12 14 0 2 4 6 8 10 12 0 2 4 6 8

for J05C

17

[3] Water Temperature Sensor (THW made anothermanufacturer)

The water temperature sensor detects the temperatureof the engine coolant water and outputs it to the ECU.The sensor uses a thermistor, which varies resistanceaccording to temperature. As the ECU applies voltageto the thermistor, it uses a voltage resulting from thedivision of the computer internal resistance and thethermistor resistance to detect the temperature.

[4] Fuel Temperature Sensor (THL)The fuel temperature sensor detects the fuel temperature and outputs it to the ECU. The sensoruses a thermistor, which varies resistance according to temperature. As the ECU applies volt-age to the thermistor, it uses a voltage resulting from the division of the computer internal re-sistance and the thermistor resistance to detect the temperature.

Q000104E

VTHW

ECU

A-GND

+5V

0

1

2

3

4

5

-40 -20 0 20 40 60 80 100 120 THW

VTHW

Coolant temperature (°C)

Ou

tpu

t vo

lta

ge

(V

)

Q000105E

VTHL

ECU

A-GND

+5V

0

1

2

3

4

5

-40 -20 0 20 40 60 80 100 120 THL

VTHL

Fuel temperature (°C)

Ou

tpu

t vo

lta

ge

(V

)

Q000106E

18

[5] Atmospheric Air Presuure Sensor (Built-in ECU)This sensor converts the atmospheric air pressure intoan electrical signal to correct full-load injection volume.

[6] Accelerator Position SensorThis sensor converts the angle of the pedal effort applied to the accelerator pedal into electricalsignals and sends them to the ECU. The accelerator sensor uses hall elements. A magnet ismounted on the shaft that moves in unison with the accelerator pedal, and the magnetic fieldorientation changes with the rotation of the shaft. The changes in the magnetic field orientationgenerate voltage.

[7] Boost Pressure SensorIn order to correct the full-load injection volume, this sensor converts the intake air pressure(absolute pressure) into an electrical signal, then amplifies it into a voltage signal to the com-puter.

Atmospheric air pressure (kPa)

Ou

tpu

t vo

lta

ge

(V

)

VPATM

4.00

101

Q000126E

Q000107

Hall elements(2 pieces)

Magnets(1 pair)

ECU

Am

plif

ier

No

. 2

Am

plif

ier

No

. 1

A-Vcc

VACCP1

A-GND

A-Vcc

VACCP2

A-GND

+5V

+5V

VAccp1VAccp2

(V)

V

4.0

3.0

2.0

1.0

0

Accelerator opening (%)Accp

50 100

Q000141E

A-VCC

VPIM

A-GND

ECU

+5VVPIM

Output valtage

(V)

4.0

2.0

0100 200 300

Intake air pressure PIM (kPa)

19

[8] Idle Set Button (made by another manufacturer)A control knob is provided within the driver’s reach,enabling the driver to set the idle speed.

[9] Main RelayTo supply current to the ECU, the main relay points close when current is applied the main relaycoil.[10] PCV RelayIt is a relay that supplies current to the supply pump’s PCV (discharge volume control valve).

ECU

A-GND

V-IMC

A-VCC+5V

Q000142E

20

3. Various Types of ControlThis system controls the fuel injection quantity and injection timing more optimally than the mechanicalgovernor or timer used in conventional injection pumps.For system control, the ECU makes the necessary calculations based on signals received fromsensors located in the engine and on the vehicle in order to control the timing and duration inwhich current is applied to the injectors, thus realizing optimal injection timing.

[1] Fuel Injection Rate Control FunctionThe fuel injection rate control function controls the ratio of the quantity of fuel that is injectedthrough the nozzle hole during a specified period.

[2] Fuel Injection Quantity Control FunctionThe fuel injection quantity control function, replaces the conventional governor function, andcontrols fuel injection to achieve an optimal injection quantity based on the engine speed andthe accelerator opening.

[3] Fuel Injection Timing Control FunctionThe fuel injection timing control function, replaces the conventional timer function, and controlsthe fuel injection to achieve an optimal injection timing according to the engine speed and theinjection quantity.

[4] Fuel Injection Pressure Control Function (Rail Pressure Control Function)The fuel injection pressure control function (rail pressure control function) uses a rail pressuresensor to measure fuel pressure, and feeds this data to the ECU to control the pump dischargequantity.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 Control output

Accelerator sensor

Rail pressure sensor

NE sensor

(Crankshaft position sensor)

TDC sensor

(Cylinder recognition sensor)

Various sensors

·Water temperature sensor

·Fuel temperature sensor

·Atmospheric air temperature

sensor etc.

Fuel control computer

(ECU)

Fuel injection rate control

Fuel injection quantity control

Fuel injection timing control

Fuel injection pressure control

Diagnosis

Atmospheric air pressure sensor

Q000109E

21

3.1 Fuel Injection Rate Control[1] Main InjectionSame as conventional fuel injection.[2] Pilot InjectionPilot injection is the injection of a small amount of fuelprior to the main injection.While the adoption of higher pressure fuel injection isassociated with an increase in the injection rate, thelag (injection lag) that occurs from the time fuel is in-jected until combustion starts cannot be reduced be-low a certain value. As a result, the quantity of fuelinjected before ignition increases, resulting in explosive combustion together with ignition, andan increase in the amount of NOx and noise. Therefore, by providing a pilot injection, the initialinjection rate is kept to the minimum required level dampening, the explosive first-period com-bustion and reducing NOx emissions.

[3] Split InjectionWhen the rotation is low at starting time, a smallamount of fuel is injected several times prior to maininjection.

Q000110

Pilot injectionMain injection

Q000111

Combustionprocess

Injection rate

Heat generationrate

TDC

High injectionrate

Large pre-mixturecombustion(NOx, noise)

Ignition delay

Small injection amountprior to ignition

Delta injection

Pilot injection

Small pre-mixturecombustion

Improvement

Q000112

Split injection

22

3.2 Fuel Injection Quantity Control[1] Starting Injection QuantityThe injection quantity is determined based on the en-gine speed (NE) and water temperature while starting,with the accelerator pressed 50% or more.

[2] Transient Injection Quantity CorrectionWhen the changes in the accelerator opening aregreat during acceleration, the increase in fuel volumeis delayed to inhibit the discharge of black smoke.

[3] Basic Injection QuantityThis quantity is determined in accordance with the en-gine speed (NE) and the accelerator opening.Increasing the accelerator opening while the enginespeed remains constant causes the injection quantityto increase.

[4] Injection Quantity for Maximum Speed SettingThe injection quantity is regulated by a value that isdetermined in accordance with the engine speed.

Q000127E

Water temperature

Sta

rtin

g in

jectio

n q

ua

ntity

Engine speed

Q000128E

Inje

ctio

n q

ua

ntity

Time

Change in accelerator opening

Injection quantityafter correction

Delay time

Q000129E

Ba

sic

in

jectio

n q

ua

ntity

Engine speed

Accelerator opening

Q000130E

Inje

ctio

n q

ua

ntity

fo

rm

axim

um

sp

ee

d s

ett

ing

Engine speed

23

[5] Maximum Injection QuantityThis quantity is calculated by adding the amount of Q-adjustment resistor correction and the amount of injec-tion quantity fuel temperature correction to the basicmaximum injection quantity that has been determinedin accordance with the engine speed.

[6] Amount of Q-Adjustment CorrectionSelects the one of eight values determined by data inROM built in ECU.Characteristic curve is fixed by the value.

[7] Amount of Injection Quantity Intake PressureCorrection

Limits the maximum injection quantity in accordancewith the intake pressure, in order to minimize the dis-charge of smoke when the intake air pressure is low.

[8] Amount of Injection Quantity by AtmosphericAir Pressure Correction

With using atmospheric air pressure sensor signal, themaximum injection quantity curve is corrected asshown in the right figure.

Q000131E

Ba

sic

ma

xim

um

in

jectio

nq

ua

ntity

Engine speed

Q000132E

Basic maximum injection quantity

8 patterns in this range.

Engine speed

Q000133E

Engine speed

Am

ou

nt

of

inta

ke

air

pre

ssu

re c

orr

ectio

n

Q000134E

Engine speed

Am

ou

nt o

f a

tmo

sp

he

ric

air p

ressu

re c

orr

ectio

n

24

[9] Idle Speed Control System (ISC)Controls the idle speed by regulating the injectionquantity in order to match the target speed, which hasbeen calculated by the computer, with the actualspeed. The functions of the ISC can be broadly divid-ed into the following two items:

• Auto ISCControls the idle speed in accordance with the watertemperature.

• Manual ISCControls the idle speed in accordance with the idlespeed indicated on the manual idle setting knob pro-vided at the driver’s seat.

• Aircon Idle-up ControlWhen the conditions shown in the chart on the rightare realized, bring the idle-up speed to 735 rpm.

[10] Auto Cruise ControlControls the actual vehicle speed by regulating the injection quantity in order to match the tar-get speed that has been calculated by the computer with the actual speed.

Q000135E

Ta

rge

t sp

ee

d

Water temperature

Q000136E

Ta

rge

t sp

ee

dISC knob terminal voltage

Q000137E

Air conditioning SW = "ON"

Conditions

Clutch SW = "ON" (clutch connection)

Neutral SW = "ON" (neutral)

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3.3 Fuel Injection Timing ControlThe characteristics of the fuel injection timing vary depending on whether it is the main injectionor the pilot injection. Although either the NE sensor or the auxiliary NE sensor is the referencefor controlling the injection timing, the NE sensor is ordinarily used for this purpose.[1] Main Injection TimingThe basic injection timing is calculated in accordancewith the final injection quantity, the engine speed, andthe water temperature (with map correction).While starting, it is calculated in accordance with thewater temperature and the engine speed.

[2] Pilot Injection timing (Pilot Interval)The pilot injection timing is controlled by adding the pi-lot interval to the main injection timing.The pilot interval is calculated in accordance with thefinal injection quantity, the engine speed, and the wa-ter temperature (with map correction).While starting, it is calculated in accordance with thewater temperature and the engine speed.

[3] Fuel Injection Pressure Control(1) Fuel Injection PressureA value is calculated as determined in accordancewith the final injection quantity and the engine speed.While starting, it is calculated in accordance with thewater temperature and the engine speed.

Q000138E

Ba

sic

in

jectio

n t

imin

g Final injectionquantity

Engine speed

Q000139E

Final injectionquantity

Engine speed

Pilo

t in

terv

al

Q000140E

Final injectionquantity

Engine speed

Ra

il p

ressu

re

4. Diagnostic Trouble Codes

No. Exhaust brake light

Meaning of the diagnostic trouble code (DTC) or the diagnosis item

Estimated cause of the malfunction

Warning light [mode]

Multiplex indication

Contents of fail-safe action

Fuel injection Exhaust brake engine retarder Cruise control Tachometer

1 – Normal — — — — — — —3 1 NE sensor system abnormal

Wiring harness open circuit, short, or defective sensor

Light ON [2] — Control by TDC sensorNormal control

StoppedNormal control

3 2 TDC sensor system abnormal Light ON [2] — Control by NE sensor3 1&2 Both NE and TDC sensors abnormal Blinking Yes* Engine stopped Stopped Stopped

4 1 Coolant temperature sensor abnormalWiring harness open circuit, short, or defective sensor

— —Control continued as 80 °C during normal operation and as -20 °C during starting Normal control Stopped Normal control

4 2 Fuel temperature sensor abnormal — — Control continued according to the coolant temperature sensor data

6 1 Starter switch system abnormal Switch seized or wiring harness short

— — Normal controlNormal control Normal control Normal control

6 3 Engine stop switch system abnormal — — Switch input invalidated

7 1 Intake air pressure sensor system abnormal Wiring harness open circuit, short, or defective sensor Light ON [2] — Control continued as intake air

pressure of 100kPa Normal control Stopped Normal control

8 1 Accelerator position sensor 1 voltage abnormal

Wiring harness open circuit, short, or defective sensor

Light ON [2] — Control continued using accelerator position sensor 2

Normal control Stopped Normal control8 2 Accelerator position sensor 2 voltage abnormal Light ON [2] — Control continued using accelerator

position sensor 18 1&2 Both accelerator position sensors voltage abnormal Blinking — Backup with idle set button

8 3 Accelerator position sensor 1 or 2 fixed voltage abnormal Light ON [2] — Control continued with the normal accelerator position sensor

9 2 Idle set button abnormal Wiring harness short — — Fixed to voltage of 0.2V when setting manually Normal control Normal control Normal control

11 1 Vehicle speed sensor system abnormal Wiring harness open circuit, short, or defective sensor — — Normal control Normal control Stopped Normal control

12 1 FSV solenoid valve system abnormalWiring harness open circuit, short, or defective solenoid valve

— — Normal controlNormal control Stopped Normal control

12 2 CBCS1 solenoid valve system abnormal When an improper ECU is installed on the vehicle

Light ON [2] —Limit injection quantity

12 3 CBCS2 solenoid valve system abnormal Light ON [2] —13 1 Exhaust brake solenoid valve system abnormal

Wiring harness open circuit, short, or defective solenoid valve / relay

— —

Normal control Stopped Stopped Normal control13 2 Engine retarder relay system abnormal — —13 3 Transmission retarder system abnormal — —13 4 Accelerator linked relay system abnormal — —14 1 PCV1 +B short

Wiring harness open circuit, short, or defective relay

Light ON [1] —

Limit injection quantity

Normal control Stopped Normal control

14 2 PCV1 GND short Light ON [1] —14 3 PCV2 +B short Light ON [1] —14 4 PCV2 GND short Light ON [1] —14 1&3 PCV1 & 2 both +B shortf1 Blinking Yes* Stopped14 2&4 PCV1 & 2 both GND shortf1 Blinking Yes* Stopped14 6 PCV relay system abnormal Blinking Yes* Normal control16 1 Rail pressure abnormal (sensor system)

Wiring harness open circuit, short, or defective sensor

Light ON [1] —

Limit injection quantity Normal control Stopped Normal control16 2 Rail pressure abnormal (output fixed) Light ON [1] —16 3 Rail pressure abnormal (excessive pumping by pump) Light ON [1] —16 4 Rail pressure abnormal (control system) Light ON [1] —

* The multiplex display screen indicates “Engine”.

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No. Exhaust brake light

Meaning of the diagnostic trouble code (DTC) or the diagnosis item

Estimated cause of the malfunction

Warning light [mode]

Multiplex indication

Contents of fail-safe action

Fuel injection Exhaust brake engine retarder Cruise control Tachometer

17 1 Flow damper activated (No. 1 cylinder)

Fuel leak

— —

Injection stopped to the cylinder in which the flow damper has been activated

Normal control Normal control Normal control

17 2 Flow damper activated (No. 2 cylinder) — —17 3 Flow damper activated (No. 3 cylinder) — —17 4 Flow damper activated (No. 4 cylinder) — —17 5 Flow damper activated (No. 5 cylinder) - For J08C only — —17 6 Flow damper activated (No. 6 cylinder) - For J08C only — —

18 1 Injector solenoid valve drive system open circuit(No. 1 cylinder)

Wiring harness open circuit

Light ON [1] —

Limit injection quantity Normal control Stopped Normal control

18 2 Injector solenoid valve drive system open circuit(No. 2 cylinder) Light ON [1] —

18 3 Injector solenoid valve drive system open circuit(No. 3 cylinder) Light ON [1] —

18 4 Injector solenoid valve drive system open circuit(No. 4 cylinder) Light ON [1] —

18 5 Injector solenoid valve drive system open circuit(No. 5 cylinder) - For J08C only Light ON [1] —

18 6 Injector solenoid valve drive system open circuit(No. 6 cylinder) - For J08C only Light ON [1] —

19 1 Injector solenoid valve drive system +B short (common 1)

Wiring harness short

Light ON [1] —

Limit injection quantity Normal control Stopped Normal control19 2 Injector solenoid valve drive system GND short (common 1) Light ON [1] —19 3 Injector solenoid valve drive system +B short (common 2) Light ON [1] —19 4 Injector solenoid valve drive system GND short (common 2) Light ON [1] —21 1 Pump not pumping (fuel discharged) Significant misalignment

during the assembly of the supply pump

Blinking Yes*Injection quantity limited; then, stopped Normal control Stopped Normal control

21 2 Pump not pumping or pressure limiter activated Blinking Yes*

22 1 ECU internally abnormalal ECU defective Light ON [1] — Limit injection quantity Stopped Stopped Stopped

22 2 CBCS solenoid system abnormal

Wiring harness open circuit, short, defective solenoid valve, or improper ECU installation

Light ON [2] — Limit injection quantity Normal control Stopped Normal control

22 3 Atmospheric pressure sensor open/short ECU defective — — Fix atmospheric air pressure to101.3 kPa Normal control Normal control Normal control

23 1 Overrun abnormal Engine speed over 3,650 rpm Light ON [1] — Injection stopped during overrun Normal control Stopped Normal control

24 1 Overheating Coolant temperature over105 °C — — Limit injection quantity Normal control Stopped Normal control

* The multiplex display screen indicates “Engine”.

27