Топливная Система Siemens Sid 201

8/9/2019 Siemens Sid 201

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HDi INJECTION

SID201


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Object ives

The objective of this document is to present:

- The fuel system,

- The air system,

- The functions of the SIEMENS SID201 ECU,

- The particle filter,

- The operating principle of the torque-sensitive engine

mounts.

All information in this document correspond to authorized

maintenance operations at the time this document was created.


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Tab le o f Con ten ts

AIR SYSTEM

ENGINE MOUNTS

PARTICLE FILTER

FUEL SYSTEM

SID201 FUNCTIONS


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FUEL SYSTEM

THE LOW PRESSURE SYSTEM

ToC

THE HIGH PRESSURE SYSTEM

THE FUEL RETURN SYSTEM


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FUEL SYSTEM

LOW PRESSURE SYSTEM

Tank Booster pump

Fuel filter

Nozzle + valve

Pressure

regulator

Chapter

Fuel cooler

High pressure pump


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FUEL SYSTEM

Booster pump

Permanent power supply(with +APC on)

Flow =180l/h

Chapter

Gauge

Booster pump


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FUEL SYSTEM

LOW PRESSURE SYSTEM

Tank Booster pump

Fuel filter

Nozzle + Valve

Pressure

regulatorFuel cooler

High pressure pump

Chapter


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FUEL SYSTEM

Pressure Regulator

Calibrated pressure: 0.5

bar (relative pressure)

Atmospheric

pressure

From booster

pump

To tank

Chapter


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FUEL SYSTEM

LOW PRESSURE SYSTEM

Tank Booster pump

Fuel filter

Nozzle + Valve

Pressure

regulatorFuel cooler

High pressure pump

Chapter


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FUEL SYSTEM

FULE FILTER

Water trap

Bleed screw

Replacement at 60.000km

Priming the system:

Ignition on during 1 minute

Chapter


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FUEL SYSTEM

HIGH PRESSURE SYSTEM

High pressure pump

Transfer pump

VCV Volume

regulator

PCV

Pressure

regulator

High pressure

elements

Supply tocommon rails

Fuel return

Chapter


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FUEL SYSTEM

High pressure pump

Low pressuresupply

Supply to common

rails

Fuel return

Transfer

pump

VCV Volume regulator

PCV Pressure

regulator

No timing needed

No disassembly

Driven by a belt

ValuesTransfer pressure 4 bar

Idle pressure 220 Bar

Maximum pressure 1650 Bar

Chapter


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FUEL SYSTEM

High pressure elementsChapter


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FUEL SYSTEM

HIGH PRESSURE SYSTEM

High pressure pump

Chapter


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FUEL SYSTEM

Common rails

Die cast common rails

The rail pressure sensor cannot be removed

No resistance measurement of the sensor

Rail pressure

sensor

Chapter


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FUEL SYSTEM

Injectors

Piezo-electric actuators Fuel return

coupling clip Piezo-electric control

6-hole injectors 150m

Power supply from 90 to 160 V

Actuator resistance 200K (+/-50K)

NO disconnection when the engine is running!

Risk of serious engine damage because

of permanent injection!

Chapter


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FUEL SYSTEM

Injectors

NO INJECTOR CLASSES TOBE TELECODED!!!

Chapter


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FUEL SYSTEM

FUEL RETURN SYSTEMChapter

High pressure pump

TcIf fuel T


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FUEL SYSTEM

Fuel Temperature Sensor

Technology: NTC probe

Purpose: allow the CMM to avoid fuel overheating

(protection of the fuel system)

2 pressure releases: T>115 then T>128c

The check valve also holds the pressure in the injector

return line (1.2 bar relative pressure)

Fuel temperature sensor

Fuel temp. sensor and

coupling with cooler

Check valve

Chapter


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FUEL SYSTEM

Fuel cooler (water/diesel fuel)

Fuel / Coolant exchanger

Built-in the oil filter base, in the centre ofthe V

Regulates the injector return line fuel

temperature on the coolant temperature.

Chapter


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FUEL SYSTEM

FUEL RETURN SYSTEM

High pressure pump

Tc

Fuel temp. sensor

Fuel cooler

Thermostatic valve

Fuel cooler

Chapter


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FUEL SYSTEM

Thermostatic ValveChapter

Attached on the central common rail Optimizes the fuel temperature increase

Built-in thermostatic element

Transition at 35c (corresponds to 3,23 K on the

fuel temp. sensor)

When fuel T > 40c

When fuel T < 35c

Injector return +

HP pump return

To fuel filter

To tank


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FUEL SYSTEM

FUEL RETURN SYSTEM

High pressure pump

Tc

Fuel temp. sensor

Fuel cooler

Thermostatic valve

Fuel cooler

Chapter


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FUEL SYSTEM

Fuel cooler (air/diesel fuel)

Under the bodyshell

Lowers the fuel temperature by

10C (vehicle not running) and

25c (vehicle running).

Chapter


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FUEL SYSTEM

Low pressure:

How is the fuel fed to the HP pump?

Booster pump + transfer pump

What is the electrical element fitted on the fuel filter?

Water trap

High pressure

How many common rails are there on the high pressure system?

3 common rails: one for each cylinder row + a central one with a pressure sensor

How many classes of injectors to be telecoded?

None

Return system

What type of exchanger is fitted on the injector return line?

Water / Fuel exchanger

What type of element ensures fuel temperature increase?

Thermostatic valve. T transition: 35c

Synthesis Chapter


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AIR SYSTEM

Chapter AIR SYSTEM DIAGRAM

11. Exhaust manifold

12. EGR exchanger

(water/exhaust gases

exchanger)

13. Electrical EGR valve

14. Pre-catalyser

upstream temp. sensor

15. Pre-catalyser

16. Pre-catalyser

downstream temp.

sensor (only on rear

cylinder row)

17. Oxidation catalyser

18. Particle filter

19. Catalyserdownstream temp.

sensor

20. FAP differential

pressure sensor

1. Air filter

2. Mass air flowmeter with

built-in intake air temp.

sensor

3. Electrically controlled

turbocharger

4. RAS (air/air exchanger)

5. FAP richness valve

6. Temp. and pressure

turbocharger air sensors

7. Helical and tangential

intake duct

8. Swirl valve control

breather

9. Swirl valve

10. Vacuum pump


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AIR SYSTEM

Air Filter

Includes the filtering cartridge.

The upper section includes:

both vents for torque-sensitive

engine mount electric valves.

both attachments for flowmeters on

front and rear cylinder rows.

Torque-sensitive engine

mount vents

Flowmeters

Chapter

AIR SYSTEM


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AIR SYSTEM

Mass Air Flowmeters

Technology: hot film, frequential signal

proportional to the air quantity.

Purpose: allow the CMM to measure the

EGR ratio.

Front and rear flowmeters identical

Built-in intake air temp. sensor (NTC

probe)

Purpose: allow the CMM to calculate thevolume of air quantity

Flow

measurement

Intake air temperature

measurement

Chapter

AIR SYSTEM


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AIR SYSTEM

Turbochargers

2 turbochargers:

Smaller less inertia reduced time lag.

Maximum pressure: 1.6 bar (relative pressure).

Variable geometry: allow turbocharger operation

over a wider rpm range.

The variable geometry is controlled by an

electrical actuator.

Electrical actuator

Chapter

AIR SYSTEM


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AIR SYSTEM

Variable Geometry

Operating principle:

Variation of the exhaust gases flow

section.

Variation of the exhaust gasesorientation over the turbine.

Design:

Vanes are hinged on a disk actuated

by a rod.

The position of the rod is adjusted by

the electrical actuator.

Chapter

AIR SYSTEM


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AIR SYSTEM

Turbocharger Actuator

d.c. motor

Worm screw and gear

Position sensor target

Same reference signal to both actuators.

The position reference is sent by the CMM(PWM signal).

Position feedback signal (inductive sensor)

used by the actuator.

Chapter

AIR SYSTEM


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AIR SYSTEM

Turbocharger Actuator

Self-diagnostic by the actuator in case of blocking or internal electronic fault.

Grounding of the control signal = blocking

Power supply

Ground

PWM control signal

& diagnostic line(V)

(s)

PWM control signal

Grounding

controlled by the

actuator

Chapter

AIR SYSTEM


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AIR SYSTEM

RAS (Turbocharger Air Cooler)

Air/air heat exchanger.

Lowers the temperature of the air

compressed by the turbochargers.

Increases the density of the air

entering the engine.

Coolant radiator

A/C condenser

Turbocharger Air

Cooler

Chapter


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AIR SYSTEM


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AIR SYSTEM

Turbocharger Pressure Sensor

Technology: piezo-resistive sensor.

Purpose: allows the CMM to know the turbocharger pressure to

adjust the actuator control.

Chapter


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AIR SYSTEM


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AIR SYSTEM

Pressure Regulation

1st case: open loop regulation: EGR operating zone

The CMM controls the actuators based on cartography definition.

(Calculated reference = X bar / then PWM = X%)

The CMM does not monitor the turbocharger pressure

Chapter

AIR SYSTEM


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AIR SYSTEM

Pressure Regulation

Turbocharger pressure

sensor

Le CMM modifies the PWM correspondingly

2nd case: closed loop regulation: outside the EGR operating zone The CMM monitors the turbocharger pressure

Chapter

AIR SYSTEM


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AIR SYSTEM

De-activation ConditionsChapter

Fault on the turbocharger pressure sensor.

Fault on the atmospheric pressure sensor.

Fault detected on a turbocharger actuator.

AIR SYSTEM


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AIR SYSTEM

Variable Swirl system: reminder about the Swirl

It is the Swirl movement of the gas flow.

ADVANTAGE: better air / fuel mixing

DRAWBACK: losses of filling

Exhaust

Intake

Swir l

Liquid Gaseous

Chapter

AIR SYSTEM


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AIR SYSTEM

Variable Swirl system: operating principle

2 separated intake ducts

helical duct

tangential duct

De-activation of the tangential duct by controlling a valve,

Increase of the flow in the helical duct increase of Swirl

Chapter

AIR SYSTEM


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AIR SYSTEM

Variable Swirl system: activation zone

Both ducts open

1 duct open

(Nm)

(tr/min)

Chapter

AIR SYSTEM


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AIR SYSTEM

Variable Swirl system: components

Default setting: valve open.

Electric valve controlled by the CMM (PWM signal).

All or nothing control: no intermediate position.

Electric valve

Vacuum pump

Control

breather

Chapter

AIR SYSTEM


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AIR SYSTEM

EGR system: components

EGR exchanger

Electrical

EGR valve

Duct

Exhaust

manifold

Chapter

AIR SYSTEM


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AIR SYSTEM

EGR system: Exhaust Gases Exchanger

Coolant / Exhaust gases exchanger,

Lowers the temperature of the exhaust gases,

Allows a higher intake of exhaust gases.

Chapter

AIR SYSTEM


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AIR SYSTEM

EGR system: Electrical EGR valves

EGR valve actuated by an electric motor.

Built-in position sensor.

Actuator controlled by the CMM with an PWM signal.

Cleaning phase when switching the ignition off: 10 activations.

Electrical actuator

EGR valve

Chapter

AIR SYSTEM


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AIR SYSTEM

EGR system: Calculation of the quantity to be re-circulated

Load

Engine rpm

EGR quant i ty = X mg/s

EGR valve posi t ion = X mm

Main parameters

Correction parameters

Pa

Engine temp.

Intake air temp.

Atmospheric

pressure

Turbocharger

temp.

Chapter

AIR SYSTEM


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AIR SYSTEM

EGR system: Closed loop regulation

Flowmeter

Position

sensor

Air flow signal: the CMM substracts the quantity of gases re-circulated.

Valve opening signal measured by the position sensor: the CMM compares the

reference position and the current position.

Chapter

AIR SYSTEM


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AIR SYSTEM

EGR system: Activation zoneChapter

De-activation threshold

of the EGR re-circulation

Maximum activation threshold

of the EGR re-circulation

Activation zone of the EGR re-circulation

AIR SYSTEM


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AIR SYSTEM

EGR system: De-activation Conditions

Conditions for progressive de-activation of the EGR function:

Altitude above 1000m (atmospheric pressure (Pa) signal)

Intake air temperature higher than 45c or less than 0c

Conditions for complete de-activation of the EGR function:

FAP regeneration

Idle over a long period of time (> 1 min)

Deceleration (foot off the pedal)

Defective EGR valve

Fault on both flowmeters

Chapter

AIR SYSTEM


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AIR SYSTEM

FAP Richness Valve

FAP Richness

Valve actuator

Intake

Not used for the EGR function.

Allow a mixture enrichment during FAP regenerations.

Stuffing function when stopping the engine.

Learning of lower / upper stops every time the engine is stopped.

Chapter

AIR SYSTEM


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AIR SYSTEM

Air Loop Diagnostic: Turbocharging and EGR

Adapt the testing conditions to the system to be diagnosed.

Correct interpretation of parameters concerning:

the EGR,

the air flow,

the turbocharger pressure.

Precautions for correct diagnostic of the air loop

Chapter


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AIR SYSTEM


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AIR SYSTEM


Parameters to be interpreted for the EGR:

Air flow values 1 & 2

must be div ided b y

two .

Current and reference

EGR valve position


air flow (global)


air flow for each cylinderrow

Chapter

AIR SYSTEM


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AIR SYSTEM

Air Loop Diagnostic: Turbocharging and EGRChapter

Example of parameters at idle < 1min

Current and reference EGRvalve position: same values

Current and reference air

flow (global): same v alues

Current and reference air flow

for each cylinder row: a

maximum +/- 80 mg/st roke

dif ference is acc eptable

AIR SYSTEM


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AIR SYSTEM

Air Loop Diagnostic: Turbocharging and EGRChapter

Example of parameters at idle > 1min

Current and reference EGRvalve position: same values:

about 5%

Current and reference air

flow (global): same v alues

Current and reference air flow

for each cylinder row: a

maximum +/- 80 mg/s t roke

dif ference is acc eptable

AIR SYSTEM


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AIR SYSTEM


Diagnostic on flowmeters / EGR Test conditions: idle


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S S


Diagnostic on flowmeters / EGR Test conditions: idle >1min

Parameters Reading:

Comparison current/reference

values air flow for each cylinder

row: not OK


values of EGR valve position: OK


values of global air flow: OK

Conclusion: the flowmeters are notdefective the fault is on the rear

EGR valve

Note: if the disymetry between the

flowmeters is still present, invert the

flowmeters

Chapter

AIR SYSTEM


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Diagnostic on the turbocharging pressure (after diagnostic of theEGR system).

Test conditions: Engine running at 2000 rpm stabilized and partial load (open

loop).

This test represents the turbocharger system performance. If the pressure

measurement is less than the reference value at this stage, a fault is present.

Observation: If the test is carried during the closed loop operating cycle, the

fault will not be visible because the CMM will increase the reference pressure forthe turbochargers until it reads Pturbo = reference Pturbo

Chapter

AIR SYSTEM


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Turbochargers

Can the turbocharger actuator position be checked in the Parameters Readingmenu?

No, it is an actuator in ternal regulat ion .

How is the CMM informed in case of actuator fault?

The reference PWM sign al sent by the CMM is gro und ed by the actuator .

How is the turbocharger pressure regulated during the EGR regulation?

Open loop from pre-def ined cartographies.

Variable Swirl

In what operating phase are both intake ducts open?

At id le, high lo ad levels, high rev, no su pply.

Is there a swirl valve position feedback sensor?

No, the system o perates in open loo p.

EGR

When is the EGR de-activated?

High loads and/or revs, id le for mo re than 1min, faul t on EGR actuator , faul t on b oth

f lowmeters, release of the accelerator pedal.

In parameters reading, what percentage corresponds to a closed EGR valve?

5%

Synthesis Chapter

SID 201 ENGINE MANAGEMENT


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FUEL FLOW MANAGEMENT CYLINDER / CYLINDER

ToC

CNS STRATEGY (COMBUSTION NOISE STRATEGY)

FUNCTIONS

REPLACEMENT

CMM CONNECTORS

SENSORS

CMM THERMAL PROTECTION

PRE/POST HEATING



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Engine Control Unit CMM: connectorsChapter

144 pins

Three 48-pin connectors.


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Engine Control Unit CMM: functions

Parallel Functions:

Engine immobilizer (ADC2)

Cooling fans control

Alternator charge

Speed regulation / limitation

Drivers information (rpm, warning indicator lights)

Chapter



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Battery

BB00

- A/C system pressure

- Engine rpm

- Coolant temp.

- A/C comp. activation

authorization / inhibition

BSICMMBSI CMM- A/C compressor status

- Additional burner activation

request

Load signal

Excitation

(PSF

1)

1320

CMM

CAN IS

Chapter Parallel Functions : alternator charge



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Battery

BB00


- Engine rpm

- Coolant temp.





request

Load signal

Excitation

(PSF

1)

1320

CMM

CAN IS

Chapter Parallel Functions : Cooling Fans control



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Battery

BB00


- Engine rpm

- Coolant temp.



CAN IS



request

Load signal

Excitation

(PSF

1)

1320

CMM

Chapter Parallel Functions : Air conditioning



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Engine Control Unit CMM: Replacement

Programming of the ADC2 code

Matching with the BSI

Telecoding ( additional heating)

Learning of the FAP richness valve and EGR valves.

Required operations:

Chapter



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SensorsChapter



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Sensors: Atmospheric pressure sensor

Technology: piezo-resistive sensor

Purpose: allow the CMM the fine tune the air volume calculation.

Utilization: limited turbocharger pressure (above a certain turbo rpm)

and EGR at high altitude.

Pa

Chapter



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Sensors: Rpm sensor

Technology: Hall effect sensor square signal ferromagnetic target forced-fitted

on the crankshaft.

Purpose: determine the engine rpm and the crankshaft position. Utilization: Quantity injected, injection point, cylinder / cylinder management,

turbocharging, EGR, pre/post-heating, torque-sensitive engine mounts, variable swirl.

It is secured on the cylinder casing blanking plate, on the flywheel side.

This sensor is not adjustable.

Chapter



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Sensors: Cylinder reference sensor

Technology: Hall effect sensor square signal

Purpose: synchronisation of the injection point with the crankshaft position

Utilization: injection order, injection point,


Chapter



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Sensors: Accelerator pedal position sensor

Technology: Hall effect sensor proportional voltage signal

Purpose: allows the CMM to determine the drivers acceleration request

Utilization: load torque request, quantities injected, injection point,

turbocharging, variable swirl , EGR, torque-sensitive engine mounts


LVV switch

connector

Hall effect sensor (x2)

Spring

Chapter


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Sensors: Dual-function brake switch

Technology: dual switch

Purpose: informs the CMM and the BSI about the drivers braking requests

Utilization: de-activation of RVV, stop lights ignition signal

This sensor is not adjustable

Chapter



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Sensors: Coolant temperature sensor

Technology: NTC probe proportional voltage signal

Purpose: informs the CMM about the coolant temperature

Utilization: pre/post-heating, injected flow, injection point, cooling fans control,

EGR, turbocharging, temperature indication

Chapter



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Cylinder / cylinder regulation strategy

Improves the operating smoothness

Based on the crankshaft acceleration analysis

Operates for engine revs less than 1100 rpm.

To obtain a better engine balance, the CMM modifies the main injection by

correcting the injected flow.

Chapter



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CNS strategy: Combustion Noise Strategy

Objectives:

Compensate the nominal value differences of the injectors,

Compensate the injector deterioration as it is used.

The CNS strategy makes it possible to keep constant theacoustical level and pollution emissions.

Principle:

Measurement of the combustion noise.

Comparison with memorized values.

Increase or decrease of the pilot injection.

Chapter



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CNS strategy: Measurement of the combustion noise

Knock sensor

One knock sensor for each cylinder row

Technology: piezo-electric sensor

Purpose: transmit the combustion noises to

the CMM (electrical signal)

Utilization: optimization of the pilot injection

Chapter



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CNS strategy: comparison with memorized values

When does the CMM compares the measured combustion noises with

the reference memorized values?

Engine coolant temp. between 80C and 100C

Engine intake air temp. above 10C

Fuel temp. between 50C and 120C

Pa above 940 hPa

Engine rpm stabilized between 1500 and 2500 rpm

Engine torque between 160 and 360 Nm

Vehicle speed above 70 km/h

Not fault memorized

Every 30 minutes under a number of conditions:

Chapter



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CNS strategy: adaptation of the pilot injection

Two corrections are memorized (applied depending on the pressure in the rail)

The correction can be positive or negative.

It represents a modification of the injector opening time.

CYLINDER # Time ( ms ) Observation

1 0,0104 Correction for rail pressure values < 600 bar0,0152 Correction for rail pressure values > 600 bar

4- 0,0008 Correction for rail pressure values < 600 bar

- 0,0008 Correction for rail pressure values > 600 bar

20,0072 Correction for rail pressure values < 600 bar

0,0152 Correction for rail pressure values > 600 bar

5 0,0008 Correction for rail pressure values < 600 bar0,0032 Correction for rail pressure values > 600 bar





Chapter



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Thermal Protection Strategy

The power electronics controlling the injectors generates a high temperature

level within the CMM.

Should there be no correction, it could exceed 100C.

An internal temperature sensor allows activation of cooling fans when the

internal temp. exceeds 96C.

Chapter



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Pre/post-heating System: objectives

Reduce the pollution emissions when starting the engine

Reduce the combustion noises when the engine is cold

Reduce the smoke emissions during mountain driving

Chapter



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Pre/post-heating System: activation

Pre-heating duration:

Minimum activation time: 4s

Maximum activation time: 200s

Post-heating duration:

Approx. 150s for coolant temperature less than 40C

Null above 60C.

Temperature -30C -10C -5C 0C 10C

Activation of glowplugs

22s 10s 8s 7s 0s

Illumination of the

indicator light20s 6.5s 5s 4s 0s

Chapter



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Pre/post-heating System: simplified diagram

CAN I/S

Ground

Power supply via

double relay

Battery power

supply via BB12

Glow plugspower supply

Control signal

Feedback: relay

activated

Activation requestPre-heating indicator light

Chapter



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Pre/post-heating System: Diagnostic

The CMM analyses the signal sent back by the pre/post-heating unit.

The feedback signal is inverted (as compared to the CMM control signal).

This function allows the CMM to detect possible relay power supply faults.

Example: control 0V / feedback 0V: the relay is not activated

12V

Glow plugs OFF

CMM control

Feedback signal

12VGlow plugs ON

Normal operation

Chapter

PARTICLE FILTER


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ToC

Regeneration synthesis

Exhaust line

FAP synthesis

PARTICLE FILTER


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Chapter FAP: Exhaust line

Pre-catalysers

Catalysers

FAP

Assembly

2 pre-catalysers

Oxidation catalyser

Particle filter

PARTICLE FILTER


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FAP: Exhaust line

Differential

pressure

sensor

Two pre-catalyser temp.

sensors

One catalyser upstream

temp. sensor

One catalyser downstream

temp. sensor

4 temperature sensors

Sensors

Differential pressure sensor

Chapter

PARTICLE FILTER


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FAP: Regeneration

Utilization of the intake FAP richness valve:

The FAP richness valve is controlled to reduce the air intake

Increase the richness

Increase the temperature

No intake air heater

No additional electrical consumers activated during the FAP regeneration

One post-injection

Chapter

PARTICLE FILTER


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FAP: synthesis

C6

Particle filter

FAP OS disymetrical cells

Injection ECU (CMM) SIEMENS SID201

Regeneration supervisor FAP 2

Additive injection management Integrated in the CMM

Additive Eolys 176

MaintenanceFAP replacement: 180.000 km

Eolys top up: 120.000 km

Chapter

Input cells

Output cells

TORQUE-SENSITIVE ENGINE MOUNTS


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ToC

OPERATING PRINCIPLE

DIAGNOSTIC

REMINDER ABOUT THE TORQUE-SENSITIVE ENGINE MOUNTS

CONTROL



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Chapter Torque-sensitive engine mounts: Reminder

These engine mounts improve the driving comfort by limiting the vibrations

transmitted by the engine to the bodyshell,

They work from idle to 1.400 rpm,

They are pneumatically controlled by two electric valves fitted directly on the

engine mounts,

The CMM regulates the system in open loop from a specific load/rpm

cartography.



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Torque-sensitive engine mounts: Reminder

Advantage of the vertical installation:

Enable the engine mounts to absorb engine jerks when driving on a bad

surface road.,

Benefits from a wider centre-to-centre distance to compensate the torque

when accelerating (therefore and increased lever arm, thus reduced the effort on

the engine mounts).

RH standard

engine mount

LH standard

engine mount

The standard engine mounts

bear the engine weight.

The torque-sensitive engine

mounts absorb the engine

movements when accelerating

Chapter



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Torque-sensitive engine mounts: rear mount efficiency

Increase from 700 to 1200 rpm

A test cell measures the load between theengine and the chassis.

Chapter



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Torque-sensitive engine mounts: operating principleChapter



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Torque-sensitive engine mounts: operating principleChapter



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Torque-sensitive engine mounts: Control characteristics

Vacuum system:

Vacuum pump with two outlets (power braking

safety)

Vacuum reserve: 500 mbar (Pabsolute)

Electrical control: Electric valves controlled by a 12V PWM

Electric valves normally open

Time lag < 7 ms

To power braking

To vacuum

reserve

Chapter



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Torque-sensitive engine mounts: Diagnostic

1st check:

Check for the presence of a modulated negative pressure on each vent.

Chapter

T iti i t Di ti



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Torque-sensitive engine mounts: Diagnostic

2nd

check:If there is no negative pressure, check for tightness between the vacuum pump

and the vacuum reserve.

3rd check:

If there is a negative pressure on one side only, check for tightness between the

defective vent and the corresponding engine mount.

5th check:

Check for tightness between the electric valve and the vacuum reserve.

4th check:

Check for the absence of fault codes on the electric valve control.

6th check:

Check for proper connection of the electric valve.

Chapter

ToC


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THE END

ToC

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Топливная Система Siemens Sid 201

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