diesel common rail

Common-rail DieselDiagnosis Training

2

High-tech Diagnosis Course for Common-railGoals

– Reduce unnecessary replacing of parts(NTF parts reaches 70% in some cases)

– Reduce troubleshooting time

– Improve overall customer satisfaction

3

High-tech Diagnosis Course for Common-railObjectives

– Improve system knowledge

– Learn DTC detection conditions

– Implement structured and logic troubleshooting procedures

4

History of Common-rail SystemDifferent variations on Common-rail– 3 Generations

Diesel EFI Common-rail

2nd-generation• HP3 Supply Pump• Discharge Valve• Injector Compensation

Code 135 - 160 MPa

3rd-generation• NSR + DPNR• Piezo Injector

160 - 180 MPa

1st-generation• Common-rail• HP2 Supply Pump• Solenoid Injector

135 MPa

Max. Common-rail Pressure

5

System OverviewCommon-rail System Diagram (for IMV)

Fuel Pressure Sensor

Pressure Limiter

Supply Pump SCV

Engine ECU

Fuel Tank

Injector

NE SignalG SignalVarious Signals

Common-rail

Fuel Cooler

Pressure Switch

Fuel Filter

Fuel System Warning Light

Other Injectors

EDU

6

System OverviewMain Components for Common-rail System– Shown for the 1KD-FTV engine on the IMV

Supply Pump•SCV (Suction Control Valve)

•Fuel Temp. Sensor

Injector

Engine Front

Injection Pipe

Fuel Inlet Pipe

Common-rail•Fuel Pressure Sensor

•Pressure Limiter

7

System OverviewFeatures of Common-rail System

High pressure fuel

Stores high pressure fuel

Injection pressure, volume and timing are controlled electrically

•High performance and fuel economy•Low noise and vibration

•Clean emission

High pressure injection in all engine speed range

Higher atomization of fuel

High accuracy engine control

8

System OverviewSensors and Actuators

Air Flow Meter

Atmospheric Temp. Sensor

Camshaft Position Sensor

Intake Restrictor Valve (Step Motor)

Glow Plug

Turbo Pressure Sensor

Water Temp. Sensor

Injector

Crankshaft Position Sensor

Intake Air Temp. Sensor

VSV (for Turbo Pressure Sensor)

E-VRV (for EGR Valve Control)

VSV (for EGR Valve Close)

Illustration is for 1CD-FTV on CDE120

9

ECD System ComponentsSupply Pump– Supplies the high pressure fuel to the common-rail

HP2 HP3

Type HP2 (Outer Cam) HP3 (Inner cam)Generation 1st 2nd/3rd

SCV 2 (Time controlled) 1 (Duty-cycle)Plunger 4 (Radial Type) 2 (Opposite type)

Weight [g (lb.)] 6040 (13.32) 3800 (8.38)

10

ECD System ComponentsSupply Pump (HP3)– Fuel flow

Click!Movie

11

ECD System ComponentsSupply Pump (HP3)– Suction and pumping operation

Click!Movie

12

ECD System ComponentsSupply Pump (HP3)– Fuel control operation (SCV opening small)

Click!Movie

13

ECD System ComponentsSupply Pump (HP3)– Fuel control operation (SCV opening large)

Click!Movie

14

ECD System ComponentsSupply Pump (HP3)– The SCV opening regulates the pumping volume to

control fuel pressure

Controls SCV

opening

Common-rail pressure

(Feedback)

Accelerator Pedal Position Sensor

SCV

Engine ECU


Crankshaft Position SensorCalculation of

target injection pressure

[Fuel Pressure Control]

15

ECD System ComponentsSupply Pump– SCV signals

HP3

16

ECD System ComponentsCommon-rail– Fuel pressure sensor (PCR)

• Detects the fuel pressure in common-rail and provides feedback

Common-rail Pressure

Sensor TipPressure Limiter

From Supply Pump

Common-rail

To Injector

[Fuel Pressure Sensor]

17

ECD System ComponentsCommon-rail– Fuel pressure sensor (PCR)

0 160Common-rail Pressure (MPa)

1.0

4.2

Outp

ut V

olta

ge (V

)

Output characteristic

18

ECD System ComponentsInjector– High pressure injection for higher atomization

Nozzle Needle

Piston

Solenoid Coil

Return toFuel Tank

From Common-rail

Nozzle Spring

Click!Movie

Nozzle SpringNozzle Needle

Control Chamber

Solenoid Coil

Injector Hole 6 or 8

Injector Pressure 135 – 180 MPa

Voltage 150 V

19

ECD System ComponentsInjector– Small injection hall (0.14 mm)

Click!Movie

0.14 mm

[Top of Injector]

20

ECD System ComponentsInjector– Difference in the injection of gasoline and common-rail

[Gasoline Engine] [Common-rail Engine]

Engine ECU

Electricity Time

Inje

ctio

n Vo

lum

e

Electricity TimeCommon-rail

Pressure

EDUEngine ECU

Constant Low Pressure

[Approx. 0.3 MPa]

Variable High Pressure

[30 – 160 MPa]

LongHigh

Injection Volume

21

ECD System ComponentsInjector– Injection volume correction

• Injector compensation code

QR Code

Injector Compensation Code

Laser Marking

Compensation Code Type (QR Code)

: Correction Point

Activation Pulse Correction TQIn

ject

ion

Quan

tity

22

High Voltage

Generation Circuit

ECD System ComponentsEDU

IJT#1

+BEDU

Battery

IJT#2IJT#3IJT#4IJF

INJ#1INJ#2INJ#3INJ#4

GND GND

COM1

Control Circuit

Volta

ge

Time

150V

0V

Engine ECU

High Voltage

23

ECD System ComponentsEDU– Injector drive signals

IJT#1

INJ#1

COM1

IJF

24

ECD System ComponentsOverview ECU Inputs

Crankshaft Position Sensor (Ne)Accelerator Pedal Position Sensor (VA)

Intake Air Temp. Sensor (THA)Water Temp. Sensor (THW)

Fuel Temp. Sensor (THF)Turbo Pressure Sensor (PIM)Vehicle Speed Sensor (SPD)Fuel Pressure Sensor (PCR)

Ignition Switch (STA)

Basic Parameters

Correction Parameters

Blower Switch (BLW)A/C Amplifier (AC)Alternator (ALT)

Engine ECU

Injector

EDU

EGR Valve

DLC3

• ••

25

ECD System ComponentsOverview ECU Outputs

Injector (Timing and duration)

Suction Control Valve

EDU (Power supply)

Intake Restrictor Valve

Glow Plug

DLC3

Engine ECU

Various Sensor• ••

EGR Valve

26

ECD System ComponentsCrankshaft Position Sensor (Ne)


27

ECD System ComponentsAccelerator Pedal Position Sensor (VPA, VPA2)

Hall ICs

Magnets

28

ECD System ComponentsTurbo Pressure Sensor (PIM)


VSV (for Turbo Pressure Sensor)

Engine ECU

29

ECD System ComponentsEGR System– Intake Restrictor Valve (Rotary Solenoid Type)– A quick response and high precise are realized by

driving a direct valve shaft

Hall IC

Magnet

MagnetSteel Layer

Magnet

Intake Restrictor Valve Position Sensor

Rotary Solenoid Type Torque Motor

30

ECD System ComponentsEGR System– Intake Restrictor Valve (Rotary Solenoid Type)

• Intake restrictor shutter valve position sensor

Intake Shutter Valve Opening Angle (deg)

Outp

ut V

olta

ge (V

)0

Engine ECU

VC

VLU

Hall ICMagnet

E20

(Full Close)70

(Full Open)Intake Shutter Valve Position

Sensor

1

5

0.7120 100

3.51

31

Common-rail Control SystemsOverall– Consists mainly two parts, fuel metering part and fuel

supply part[Electrical Part]

[Mechanical Part]

Supply Pump

Injector

EDUVarious Sensor Engine ECU

•Injection Volume Control•Injection Timing Control•Idle Speed Control•Fuel Pressure Control

•Injection rate Control•Turbo Control•EGR Control•Glow Control•Diagnosis

Common-rail

32

Common-rail Control SystemsFuel Injection Volume Control– Injection volume decision

• Engine ECU compares the basic and maximum injection volumes, and determine the smaller calculated value to be the final injection volume

Engine ECU

EDU

Injector

Basic Injection Volume

Maximum Injection Volume

Fuel Pressure

Compensation Value

Injector Feedback Value

Decision on DurationComparison

33

ISC* Correction

Common-rail Control SystemsFuel Injection Volume Control– Basic injection volume

Engine ECU


(Map Data in ECU)

Basic Injection Volume Correction

Accelerator Pedal Position Sensor (VPA)

Crankshaft Position Sensor (Ne)

Water Temp. Sensor (THW)

Clutch Switch (CLSW)

Vehicle Speed Sensor (SPD)

*: Idle Speed Control

+

34

Common-rail Control SystemsFuel Injection Volume Control– Basic injection volume


Engine Speed

[Basic Injection Volume Pattern]: Amount of Accelerator Pedal Effort (VPA)

Idle

10% 20% 30%

50%

100%(Full Load)

35

Overheating Protection

Common-rail Control SystemsFuel Injection Volume Control– Maximum injection volume

Intake Air MassEngine ECU

Basic/Maximum Injection Volume

(Map Data in ECU)

Maximum Injection Volume Correction


Air Flow Meter (VG)


Turbo Pressure Sensor (PIM)Intake Air Temp. Sensor (THA)

Fuel Temp. Sensor (THF)

Fuel Pressure Sensor(PC, VPC)

36

Common-rail Control SystemsFuel Injection Volume Control– Maximum injection volume

Engine Speed

[Maximum Injection Volume Pattern]

Intake Air Volume-small

Injection Volume Varies by

Required Volume

Intake Air Volume-large

37

Common-rail Control SystemsFuel Injection Volume Control– Final injection volume decision

• Case of VPA 30% Selects basic injection volume

Engine Speed

Injection Volume

30% VPA

: Basic Injection Volume: Maximum Injection Volume

Selects lowest

[Determining Injection Volume]

38

Common-rail Control SystemsFuel Injection Volume Control– Final injection volume decision

• Case of VPA 100% Selects Max. injection volume

Engine Speed

[Determining Injection Volume]

Injection Volume

100% VPA

: Basic Injection Volume: Maximum Injection VolumeSelects lowest

39

Common-rail Control SystemsFuel Injection Volume Control– Injection volume correction by intake air

[Intake Air Pressure Correction] [Intake Air Temp. Correction]

Correction Coefficient

Turbo Pressure Sensor Output (V)3

1

Increase

Decrease


Decrease

40

1

Intake Air Temp. (deg)

Overload ProtectionPressure Correction

40

Common-rail Control SystemsFuel Injection Volume Control– Injection volume correction by fuel temperature

[Fuel Temp. Correction]


Fuel Temperature (deg)

Increase

Decrease

1

40

41

Common-rail Control SystemsFuel Injection Volume Control– Injection volume correction by water temperature

[Water Temp. Correction]


Water Temperature (deg)

Increase

40

1

42

Common-rail Control SystemsFuel Injection Volume Control– Injection duration

Pressure Limiter

Engine ECU

NE SignalG SignalVarious Signals

Common-rail

Injector

EDU


FromSupply Pump

Decides opening time of injector by final injection volume

Controls opening timing of injector

43

Common-rail Control SystemsFuel Injection Volume Control– Injection duration

Engine ECU

EDU

Injector


Maximum Injection Volume

Comparison Volume

Injector Feedback Value

Injector Compensation

Value

INJ Time Calculation

Fuel Pressure

44

Common-rail Control SystemsFuel Injection Volume Control– Injection volume control during starting

Engine ECU


Corrections Water Temp. SensorCrankshaft Position Sensor

+

Starting Injection Volume



Water Temperature (deg)

Increase

40

1

45

Common-rail Control SystemsFuel Injection Timing Control– Basic injection timing

(injection timing control after started)

Engine ECU



+

EDUInjector

Injection Timing Correction

Basic Injection Timing

Turbo Pressure Sensor (PIM)


Intake Air Temp. Sensor (THA)

46

Common-rail Control SystemsFuel Injection Timing Control– Injection timing control during starting

Engine ECU

Target Injection Timing Correction




47

Common-rail Control SystemsFuel Injection Timing Control– Injection timing corrections

• Target injection timing = Basic timing + corrections

BTDC(deg)

Engine Speed (rpm)

15

[Basic Target Injection Timing]

: Amount of Accelerator Pedal Effort (VPA)

Timing Advance

(°CA)

[Intake Air Pressure Correction]

Intake Air Pressure (PIM)

: Engine Speed

Timing Advance

(°CA)

[Water Temp. Correction]

Engine Speed (rpm)

: Water Temp.

Full Load

Light Load

HOTCOLD

High rpmLowrpm

48

Common-rail Control SystemsIdle Speed Control– Target idle speed control

Engine ECU


Injector Volume

Correction

Target Engine Speed Calculation

Actual Engine Speed

Comparison


Vehicle Speed Sensor (SPD)


A/C Amp. [Idle-up Signal] (ACT)

Electric Load


49

Common-rail Control SystemsIdle Speed Control– Feedback correction

• Idle speed fluctuations are detected by comparingt values

Crankshaft Position Sensor Signal (Ne)

360°CA

50

Common-rail Control SystemsFuel Pressure Control– Target injection fuel pressure

Controls SCV

opening

Common-rail pressure

(Feedback)


SCV

Engine ECU


Crankshaft Position SensorCalculation of

target injection pressure

[Fuel Pressure Control]

51

Common-rail Control SystemsFuel Pressure Control– Target injection fuel pressure

• To control target fuel pressure in common-rail by SCV

Target Injection Fuel Pressure

Engine Speed (rpm)

: Calculated Final Injection Volume

MAX

MIN

52

Common-rail Control SystemsInjection Rate Control– Injection rate control

Combustion Process

Injection Rate

Heat Generatio

n Rate

Ignition Delay

SmallPre-mixture Combustion

[Pilot Injection]High Injection

Rate

[Delta Injection]Small Injection Amount Prior to

Ignition

TDC

Heat LargePre-mixtureCombustion(NOx, Noise)

Improvement

53

Common-rail Control SystemsInjection Rate Control– Pilot injection

Engine ECU


EDUInjector


Pilot Injection(Volume, Timing, Interval)




Basic Pilot Timing

Correction

54

Common-rail Control SystemsInjection Rate Control– Main injection timing

Camshaft Position Sensor Signal (G)

Fuel QuantityInjection Timing

Pilot Injection Main Injection

55

Common-rail Control SystemsOther System Operation– EGR control system

Intake Restrictor

Valve

Intake Restrictor Valve Position Sensor

Intake Restrictor Valve Control Motor Engine

ECU

E-VRV(for EGR valve control)

VacuumDamper

EGR Valve

EGR Valve Position Sensor

Engine

VacuumPump




Water Temp. Sensor

Intake Air Temp. SensorAtmospheric

Pressure Sensor

56

Common-rail Control SystemsOther System Operation– Intake restrictor valve control system

Step MotorAir IN

Reduction Gears Intake Restrictor Valve

Throttle Valve Fully Opened Switch

Air Out

57

Common-rail Control SystemsOther System Operation– Intake restrictor valve control system

Intake Restrictor Valve

Intake Restrictor Valve Position

Sensor

Intake Restrictor Valve Control

Motor

Engine ECU







58

Common-rail Control SystemsOther System Operation– Glow control system

Glow Plug

Ignition Switch

Engine Speed(rpm)

ON

OFF

ON

OFF

Starting Engine

After Glow Time

0

Engine Coolant Temp. [°C (°F)]

Afte

r Glo

w Ti

me

(sec

.)

120

0 20(68)

40(104)

diesel common rail

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