VP30 44 Diesel.eng.Management.

PowerPoint Presentation

Diesel injection and engine management systems

Course content for day 1Overview and usage of the diesel systemBosch VP 30 / VP 44 fuel injection systemVP 30 / VP 44 engine management system - componentsVP 30 / VP 44 engine management system - operation VP 30 / VP 44 system Diagnostics

Diesel injection and engine management systems

Course content for day 2 Delphi common--rail fuel injection systemCommon--rail engine management system --components Common--rail engine management system -- operationcommon--rail system -- Diagnostics

Diesel injection and engine management systemsLesson 1:Overview and usage of the diesel systemsOverview of the fuel injection systems

3 Bosch unit injector (1.9L TDI)4 Delphi common-rail(1.8L/2.0L Duratorq TDCi; 2.0L shown)1 Bosch VP 30 distributor-type fuel injection pump(1.8L Endura DI, 2.0L/2.4L Duratorq DI)2 Bosch VP 44 distributor-type fuel injection pump(2.0L/2.4L Duratorq-DI)

A VP 30/VP 44 fuel injection systemB Common rail fuel injection system1 Visteon EEC V PCM2 Delphi Injector driver module (IDM)3 Visteon EEC V PCMDiesel injection and engine management systemsFuel injection timing (control)

A Combustion pressureB Compression pressureC Bottom dead centerD Top dead centerE Piston positionF Pressure in combustion chamber

Emissions of oxides of nitrogen and hydrocarbonsA Advanced start of fuel injectionB Retarded start of fuel injectionC Crankshaft angleD Exhaust emissionsX Optimum start of fuel injectionAs the start of fuel delivery is easier to calculate than the actual start of fuel injection, the fuel injection system and the engine are synchronized at the start of fuel delivery. This is possible because there is a defined relationship betweenthe start of fuel delivery and the start of fuel injection.1 ignition delay2 Fuel injection delay3 End of fuel injection4 End of combustion5 Start of fuel delivery6 Start of fuel injection7 Start of combustionFuel injection timing (control)

If the start of fuel injection is advanced, thisincreases the ignition delay and increases thetemperature in the combustion chamber and hencethe oxides of nitrogen (NOx) emissions. If the start of fuel injection is retarded, this can leadto incomplete combustion and thus incompletelyburnt hydrocarbons (HC). In addition, thecombustion must be terminated before the exhaustvalve opens.Exhaust emissions

During combustion, the main products are water(H2O) and carbon dioxide (CO2) plus tinyconcentrations of:-- carbon monoxide (CO),-- unburnt hydrocarbons (HC),-- oxides of nitrogen (NOx) as a by-product,-- sulphur dioxide (SO2) and sulphuric acid(H2SO4),-- particulates.

Overview of the fuel system

A Fuel return lineB Fuel injection lineC Fuel feed1 Fuel injector2 Pump control unit3 VP 30/VP 44 distributor-type fuel injection pump4 Fuel filter5 Fuel cooler (only in VP 44 pump)6 Fuel pump (only in VP 44 pump)7 Fuel tank8 EEC V PCMVP 30 pump Overview

1 Vane cell pump2 Rotation angle sensor3 Roller ring4 Pump control unit5 Plug connection6 Axial piston7 High-pressure solenoid valve8 Pressure valve9 Fuel injection timing solenoidvalve10 Injection timing advance device11 Cam plate12 Pulse generatorFuel metering by the high-pressure solenoid valve

A ChargingB DeliveryC End of delivery1 Axial piston2 High-pressure chamber3 Annular channel (inlet)4 Coil5 Valve needleChargingA --- The axial piston is moving in the reverse direction.The high-pressure solenoid valve and thus the inletare opened. At a time determined by the pump control unit the high-pressure solenoid valve is opened again andthe valve needle opens the inlet passage.DeliveryB-- The axial piston is moving in the forwards direction, the control port is opened. a mechanically operated distributor-type fuelinjection pump) is not required.6 Inlet passage7 Direction of stroke of axial piston8 To fuel injector9 Control port10 Fuel returnC-- The axial piston is still moving forwards, the controlport is still open. At a time determined by the pump control unit the high-pressure solenoid valve is opened again and the valve needle opens the inlet passage.End of deliveryThe closing point of the valve determines the beginningof delivery of the fuel injection pump.VP44 Pump overview

1 Vane cell pump2 Rotation angle sensor3 Camring4 Pump control unit5 Pump control unit electrical connector6 Radial piston high-pressure pump7 Distributor shaft8 High-pressure solenoid valve9 Pressure valve10 Fuel injection timing solenoid11 Fuel injection timing advance device12 Pulse generating rotorStopping the engine

To stop the engine, the PCM sends the signal quantity to be injected = 0 to the fuel injection pump. The valve needle of the high-pressure solenoid valve no longer closes the inlet passage so that no pressure build-up can occur and the engine stops.Fuel injection timing advance function

1 Camring2 Timing advance piston compression spring3 Control piston4 Control piston compression spring5 Discharge passage6 Fuel injection timing solenoid valveopened (fuel flow to low-pressure side ofvane cell pump)7 Annular chamber of hydraulic stop8 High-pressure side of vane cell pump9 Fuel injection timing advance piston10 Volume of fuel injection timing advance piston11 Discharge passage12 Control slide13 Fuel injection timing solenoid closing14 To low-pressure side of vane cell pumpB is advancedpositionC is retardedposition

16 Passive anti-theft system (PATS) -- transceiver17 PCM18 Smart charge generator control19 Data link connector (DLC)20 Anti-lock brake system (ABS) control unit21 ABS/stability assist control unit22 Solenoid valve for intake manifold valve (stop valve)23 EGR solenoid valve24 Boost pressure solenoid valve25 Preheat warning indicator/malfunction indicator26 Glow plugs27 Cooling fan motors28 Electric booster heater29 Wide-open throttle air conditioning cutoff (WAC)30 Air conditioning (A/C) compressor clutch31 Additional fuel pump (only with VP 44)1 Crankshaft position (CKP) sensor2 Cylinder head temperature (CHT) sensor3 Manifold absolute pressure (MAP) sensor4 Intake air temperature (IAT) sensor5 Temperature and manifold absolute pressure (T-MAP) sensor6 Mass air flow (MAF) sensor7 Barometric pressure (BARO) sensor8 Position sensor in exhaust gas recirculation (EGR) valve9 Accelerator pedal position (APP) sensor10 Brake on/off and pedal position (BPP) switches11 Clutch pedal position (CPP) switch12 Vehicle speed sensor (VSS)13 Ignition switch14 VP 30/VP 44 distributor-type fuel injection pump with pump control unit15 Instrument clusterDiesel injection and engine management systemsEEC V powertrain control module (PCM)

A 5th generation EEC powertrain control module (EEC V PCM) with a 104-pin connector is used.The PCM controls:-- the quantity of fuel injected and start of fuel delivery,-- exhaust gas recirculation (EGR) system,-- glow plug control,-- PATS,-- cooling fans,-- torque control (stability assist, traction control),-- air conditioning compressor,-- charging pressure,-- generator (smart charging),-- diagnostics,-- fault strategies,-- communication with other vehicle systems.The PCM evaluates the incoming signals from the sensors, compares these with the corresponding stored data in the software and produces signals to control the actuators.The PCM contains several analogue/digital converters. These convert analogue input signals (e.g. CHT, MAP and IAT signals) into digital signals (counts) required by the PCM for further processing.

1 Connector2 PCM family numberEEC V Powertrain control module (PCM) (continued)

PCM identification 3 Tear-off tag4 Part numberOn the PCM there is a sticker allowing identification of the right PCM for the right engines.

PCM circuit board structure1 SCP data bus controller2 Intel 196 microprocessor with integral random access memory (RAM)3 Computing unit for passive anti-theft system (PATS)4 Electronically erasable programmable read only memory (EEPROM) -- holds vehicleidentification (VID), PATS and engine adaptation data among other things5 Output drivers6 Flash electronically erasable programmable read only memory (FEEPROM) -- contains enginestrategy and engine calibration7 CAN data bus controllerPassive anti-theft system (PATS)

The passive anti-theft system (PATS) acts on the engine management system. This ensures that the engine cannot be started by unauthorized persons.The starter motor is disconnected and the quantity of fuel to be injected is reduced to 0. The glow plug warning indicator flashes with a frequency of 4 Hz. PATSThe hardware of the phase 2 PATS system is located on the board of the PCM (combined PATS).Sensors

The MAF sensor works on the hot wire principle and supplies an analogue voltage signal between 0 and 5 volts.The MAF sensor is used purely to control the exhaust gas recirculation (EGR) (closed loop) and not for fuel metering unlike on a petrol engine.

The MAP sensor supplies the PCM with an analogue voltage signal between 0 and 5 volts. The MAP sensor measures the charging pressure (boost pressure) in the intake manifold. The higher the charging pressure, the greater the maximum possible quantity of fuel which can be injected according to the position of the accelerator pedal or engine load.Mass air flow (MAF)The MAP signal influences the following functions:-- quantity of fuel to be injected,-- EGR system,-- turbocharger controlSensors

Intake air temperature (IAT) sensor

The IAT sensor supplies the PCM with an analogue voltage signal between 0 and 5 volts. The IAT sensor measures the intake air/charge air temperature.The signal is used as a correction factor to take account of the effect of the temperature on the density of the charge air.The IAT signal influences the following functions:-- quantity of fuel to be injected,-- start of fuel delivery,-- EGR system.

Temperature and manifold absolute pressure (T-MAP) sensorThe T-MAP sensor combines the IAT and MAP sensors in one component. Therefore, the T-MAP sensor also performs the same functions as the IAT and MAP sensors.The use of the T-MAP sensor or the IAT and MAP sensors depends on the variant and has no technical background.Sensors

Cylinder head temperature (CHT) sensor The cylinder head temperature (CHT) sensor supersedes the ECT sensor and the temperature sensor for the temperature gauge in the instrument cluster.The CHT sensor is screwed into the cylinder head and measures the temperature of the material in place of the temperature of thecoolant.If the CHT sensor is removed, a new sensormust always be fitted and tightened to exactlythe specified torque. Otherwise, damage to thesensor (e.g. due to deformation of the tip of thesensor) cannot be excluded.Example showing location of CHT sensor on2.4L Duratorq DI1 Cylinder head2 Sensor tip3 CHT sensor

The CHT sensor is a thermistor, which is a resistor with a negative temperature coefficient (NTC resistor).Sensors

At high temperatures the resolution of the CHT sensor is not large enough to cover the entire temperature range from --40.C to 214.C adequately. Therefore, the temperature characteristic is shifted in the PCM by activating a second resistor.1 PCM2 Second resistor (pull-up resistor)3 First resistor4 CHT sensor (NTC resistor)5 Sensor output signal6 Analogue/digital converter7 Microprocessor8 ECT sensor as comparisonThe voltage signal is digitized in the analogue/digital converter and passed in the form of counts to the microprocessor which gives thesecorresponding temperature values.

1 First characteristic2 Point at which pull-up resistor is (de)activated3 Second characteristicA CountsB Voltage (volts)C Material (sensor) temperature The first characteristic covers the material temperature from --40.C to approximately 78.C. Then, a transistor in the PCM activates a secondpull-up resistor to extend the sensor signal function. This second characteristic covers the material temperature from approximately 62.C to 214.C.Cylinder head temperature (CHT) sensorSensors

CHT signal use:-- Quantity of fuel to be injected-- Start of fuel injection-- Idle speed-- Glow plug control-- EGR system-- Actuation of the temperature gauge and glowplug warning indicator

If the sensor malfunctions or the engine overheats, the engine overheating safety function is activated. In this mode the engine power output is reduced by injecting less fuel. If the engine temperaturecontinues rising, the engine is stopped depending on the vehicle variant.Cylinder head temperature (CHT) sensorSensors

Crankshaft position (CKP) sensorThe CKP sensor is an inductive pulse generator. It scans a uniform ring of cast teeth on the circumference of the flywheel.In all, there are 2 x 17 cast teeth on the circumference of the flywheel, with two extended cast teeth indicating bottom dead center and top dead center with a consequent interval of 180 degrees between them.

A Higher engine speedB Lower engine speed1 Zero origins: gap narrow/amplitude large2 Zero origins: gap wide/amplitude smallThe engine speed is derived from the distance between the origins of this voltage signal. The shorter this distance, the higher the engine speed.In addition, the acceleration of the flywheel during each power stroke can be calculated from CKP signal.

SensorsVehicle speed sensor (VSS)The VSS works on the Hall effect principle (noton Transit) and emits a rectangular voltagesignal the frequency of which is proportional tothe instantaneous vehicle speed.The signal is used:-- for gear calculations,-- as information for the trip computer,-- as information about the vehicle speed for the instrument cluster,-- as information for the speed control system incorporated in the PCM.

The APP sensor is a resistor which can be varied by changing the angle of the accelerator pedal. This takes the form of a sliding contact potentiometer (in all 3 potentiometers). If two potentiometers should fail, the engine only runs at fast idle speed.Actutators

Exhaust gas recirculation (EGR) solenoid valve and boost pressure solenoid valveThis vacuum is controlled by curent signals fromthe PCM so that the charging pressure (boostpressure) is controlled through a vacuumdiaphragm unit and the EGR flow is controlledthrough the EGR valve.The current of these signals determines the vacuumwhich passes to the EGR valve or to thevacuum diaphragm unit of the turbocharger.

1 Exhaust gas recirculation (EGR) solenoid valve2 Boost pressure solenoid valve

The solenoid valves are supplied with vacuum by the vacuum pump.Components of distributor-type fuel injection pump

Pump control unit The pump control unit is mounted on the distributor-type fuel injection pump from above. It is fitted with a 9-pin connector which connects the pump control unit to the PCM and through which the two control modules communicate.The exchange of data takes place through the CAN databus and hard-wired circuits. The pump control unit is cooled with fuel which passes through a channel under the pump control unit housing. The pump control unit performs the calculations for the actuating signals for the high-pressure solenoid valve and the fuel injection timing solenoid valve from the information provided by the rotation angle sensor and the PCM. On the underside of the pump control unit there is a fuel temperature sensor to measure the instantaneous fuel temperature.

Components of distributor-type fuel injection pump (continued)

High-pressure solenoid valve

5 Magnet armature6 Valve needle7 Closing direction8 Valve seat1 Pump control unit2 PCM3 Magnet4 CoilThe high-pressure solenoid valve is closed (energized) or opened (de-energized) by the pump control unit.The closing time determines the delivery timeof the high-pressure pump. This allows precisemetering of the quantity of fuel to be injected.Components of distributor-type fuel injection pump (continued)

Fuel injection timing solenoid valve

1 Fuel injection timing device2 Fuel injection timing solenoid valve3 Valve needle4 Fuel supply from fuel tank5 Transfer pump (vane cell pump) The fuel injection timing solenoid valve is located on the underside of the fuel injection pump in the fuel outlet passage from the fuel injection timing device. The fuel injection timing solenoid valve acts as avariable throttle through rapid cycling of the valve needle. This allows it to influence the control pressure all the time so that the fuel injection timing device can adopt any position between advance and retard.Components of distributor-type fuel injection pump (continued)

Rotation angle sensor

Rotation angle sensor in VP 44 The rotation angle sensor is mounted so that it can rotate on a bearing ring which is fixed to the roller ring (VP 30) or cam ring (VP 44) and the fuel injection timing device. The rotation angle sensor is mounted rotatably asthis must produce its signal in relation to the angular position of the cam ring (VP 30) or roller ring (VP 44).Components of distributor-type fuel injection pump (continued)

5 Driving shaft6 Roller ring/cam ring/fuel injection timing device connection7 Tooth gap1 Flexible film conductor2 Rotation angle sensor3 Rotatable bearing ring4 Pulse generating rotor (fixed on driving shaft) The pulse for the rotation angle sensor is providedby a pulse generating rotor which is fixed on thedriving shaft. It has four tooth gaps (correspondingto the number of cylinders of the engine) spreadevenly around its circumference.Rotation angle sensor The sequence of teeth and tooth gaps is scanned By a rotation angle sensor. The rotation angle sensor produces its signal inrelation to the angular position of the rollerring/cam ring. When the fuel injection timing is altered by the fuel injection timing device, the roller ring/cam ring and hence the rotation angle sensor is turned in the advance or retard direction.The instantaneous position of the fuel injection timing device required to control the fuel injection timing is also determined by comparison of the signals from the CKP sensor and the rotation angle sensor.VP 30/VP 44 fuel injection systemOperation

Calculation for fuel metering

For calculations for the fuel metering twodifferent strategies are employed:-- engine starting,-- engine running.Calculations when starting engine1 Fuel injector2 VP 30/VP 443 Signal for quantity of fuel to be injectedQuantity of fuel for startingWhen starting, the quantity of fuel to be injected is calculated according to the engine temperature and engine speed. The quantity of fuel for starting is provided from when the ignition is switched on until a certain minimum engine speed is reached. The driver has no influence on the quantity for starting.4 PCM5 Cylinder head temperature (CHT) sensor6 Crankshaft position (CKP) sensor

Normal drivingFor normal driving, the quantity of fuel injected is calculated from the following main inputs:-- accelerator pedal position (APP),-- engine speed. In addition, the calculation for the quantity of fuel to be injected is influenced by other factors (correction factors) such as engine temperatureand charging pressure for example.VP 30/VP 44 fuel injection systemOperation

1 Accelerator pedal position calculation 2 Bucking damper3 Calculating unit4 Limiter5 Signal to fuel injection pump6 Idle speed calculation While the engine is running, the fuel metering carried out by the PCM is based on one of the following two calculations:-- idle speed,-- accelerator pedal position. Both calculations are carried out in parallel andindependently of one another all the time. The calculated values based on idle speed and accelerator pedal position are compared with one another by a calculating unit. This calculating unit then decides which calculation (idle speed or accelerator pedal position) is used as output signal for the fuel injection pump. The calculating unit always selects the greater value for the quantity of fuel to be injected.Calculation for fuel meteringVP 30/VP 44 fuel injection systemOperation

Calculation for fuel metering (continued)Bucking damperA software filter is provided between the accelerator pedal position calculation and the calculating unit. If the accelerator pedal is depressed or released suddenly, this results in a substantial change in desired quantity of fuel injected and hence the torque delivered.This abrupt change in load could produce unpleasant bucking oscillations (speed fluctuations)of the powertrain in its elastic mountings. The bucking damper reduces these as follows:-- When the engine speed rises, comparatively less fuel is injected; when the engine speed falls, more fuel is injected.

In addition, the software filter prevents a suddendrop in engine speed when changing gear.Sudden movement of accelerator pedal1 Engine speed2 Abrupt movement of accelerator pedal (drivers wish)3 Engine speed variation without active damping to prevent bucking4 Engine speed variation with active damping to prevent bucking5 Time

VP 30/VP 44 fuel injection systemOperationStopping the engineThe way in which the diesel engine works, the engine can only be stopped by cutting the fuel supply.With the fully electronic engine management, this is achieved by the PCM specifying quantity of fuel to be injected = 0. The corresponding solenoid valves for the fuel injection are no longer actuated and the engine is stopped.Cylinder balancing On top of the external loads described previously there is the matter of combustion quality and theinternal frictional forces which must be compensated. These alter minutely but continuously throughout the entire service life of the engine. In addition, the individual cylinders do not always produce the same torque over the entire life of theengine. The reason for this is mechanical tolerances and changes during the life of the engine. Thesewould result in uneven engine running, particularly at idle. The cylinder balancing system measures the accelerations of the crankshaft after eachcombustion operation with the aid of the CKP sensor and compares these with one another.

The quantity of fuel to be injected into each cylinder is adjusted individually on the basis of the differences in engine speed so that as far as possible all the cylinders deliver the same amount of torque.VP 30/VP 44 fuel injection systemOperation

In the Ford Mondeo pilot injection is employed with the VP 30/VP 44 fuel injection system. Pilot injection is an advance fuel injection operation controlled on a time basis by the fuel injection pump in addition to the normal two-stage injection process (two-spring nozzleholder principle).1 Top dead center (TDC)2 Pressure variation without pilot injection3 Combustion pressure in cylinder4 Pressure variation with pilot injection5 Nozzle needle lift6 Nozzle needle lift during pilot injection7 Nozzle needle lift during main injection8 Crankshaft angleThe pilot injection preconditions the combustion chamber and also has the following effects:-- The compression pressure is raised slightly by a preliminary reaction or partial combustion, shortening the ignition lag of themain injection operation and reducing the increase in combustion pressure (producing smoother combustion).

These effects reduce combustion noise and Nox emissions.Fuel injectionVP 30/VP 44 fuel injection systemOperation

Control of fuel injection pump1 PCM2 Pump control unit3 High-pressure solenoid valve4 Fuel injection timing solenoid valve5 Fuel injection timing device6 Camring7 Pulse generating rotor for rotation angle sensorThe pump control unit is an intelligent actuator. The information on the start of fuel delivery and the quantity of fuel to be injected received from the PCM is converted into actuating signals for thehigh-pressure solenoid valve. In addition, the pump control unit actuates the fuel injection timing device to set the desired start of fuel delivery (control of start of fuel delivery).

To control the fuel injection timing, the pump control unit requires the pulses from the rotation angle sensor as a reference mark (closed loop).VP 30/VP 44 fuel injection systemOperation

Fuel injection timing The fuel injection timing system, consisting of the rotation angle sensor, fuel injection timing device and fuel injection timing solenoid valve, has the task of advancing or retarding the start of fuel delivery depending on engine speed, load, noise and exhaust emissions and engine temperature andambient air temperature. The timing is set by the pump control unit which actuates the fuel injection timing solenoid valve accordingly with pulsed signals.

Precise angle of actuation of high-pressure solenoid valve The instantaneous angular position (advance setting of the fuel injection timing device) is determined precisely by means of the rotation angle sensor. Actuation must take place at the correct angle to ensure that both the closing point and the opening point of the high-pressure solenoid valve occur at the right time during the corresponding lifting movement of the cam of the high-pressure pump.1 PCM2 Pump control unit3 High-pressure solenoid valve4 Fuel injection timing solenoid valve5 Fuel injection timing device6 Camring7 Pulse generating rotor for rotation angle sensorVP 30/VP 44 fuel injection system Operation

1 CKP sensor2 PCM3 Monitoring signal from pump control unit4 Missing tooth in sensor rotor of rotation angle sensor5 Rotation angle sensor6 Fuel injection pump with pump control unit7 CAN data bus (quantity of fuel to beinjected, fuel injection point)8 CKP signal9 Fuel injection pump relayControl of fuel injection pump (continued)Synchronization of fuel injection pump When installed in position, the fuel injection pump is in a fixed position. This means that the start of fuel delivery cannot be adjusted by turning the fuel injection pump. Therefore, mechanical tolerances (extension of the driving chain/ toothed belt and material tolerances)require synchronization of the system.Safety functionThe pump control unit of the fuel injection pump is monitored for malfunctions by the PCM. For this, the pump control unit sends a monitoring signal to the PCM every 50 ms.Configuration of pump control unit with PCMThe pump control unit and the PCM are matched to one another as regards engine management and passive anti-theft system. This means that after the fuel injection pump is changed, the new pump control unit must be configured with the PCM and vice versa. The configuration must be carried outwith the aid of worldwide diagnostic system

1 Exhaust gas recirculation (EGR) solenoid valve2 Mass air flow (MAF) sensor (only with variable turbocharger)3 PCM4 Oxidation catalyst5 Turbocharger6 Exhaust gas recirculation (EGR) valve7 Vacuum pump8 Position sensor in EGR valve (only withturbocharger with fixed turbine geometry)9 Intercooler (not on all variants)10 EGR cooler (not on all variants)Exhaust gas recirculation (EGR) systemVP 30/VP 44 fuel injection system Operation

The combustion temperatures are raised further by the use of the direct injection process.Both lead to increased formation of oxides of nitrogen (NOx) in the exhaust.

An EGR system is used to keep these NOx levels in the exhaust within the required limits.The exhaust gas recirculation takes place at partialload by mixing the exhaust gases with the intakeair. This reduces the concentration of oxygen in the intake air. In addition, the exhaust gas has a higher specific thermal capacity than air and the water content in the recirculated exhaust gas also lowers the combustion temperatures. These factors reduce the combustion temperatures (and hence the Nox level) and also reduce the quantity of exhaust gas expelled.The PCM requires feedback on the recirculated quantity of exhaust gas. Two different systems are used for this which differ through thefollowing components:-- position sensor in the EGR valve (on engines with a turbocharger controlled by a wastegate),-- MAF sensor (on engines with a variable turbocharger). In both systems, the EGR valve is actuated by vacuum from the EGR solenoid valve. The pulse duty cycle with which the EGR solenoid valce is actuated by the PCM determines the vacuum which reaches the EGR valve.

System with position sensor in EGR valve

The position sensor in the EGR valve tells thePCM the instantaneous position of the EGR valve.From this the PCM can determine theinstantaneously recirculated quantity of exhaust gasdepending on the intake manifold pressure (MAP),forming a closed loop.System with MAF sensor The quantity of exhaust gas recirculated when the EGR valve is opened directly affects the measurement of the MAF sensor. During the exhaust gas recirculation, the reduced air mass measured by the MAF sensor exactly matches the value of the recirculated exhaust gases.If the quantity of recirculated exhaust gas becomes excessive, the induced air mass drops to a certain limit. The PCM then reduces the level of recirculated exhaust gases, forming a closed loop.

VP 30/VP 44 fuel injection system Operation

Exhaust gas recirculation (EGR) system

Control of charging or boost pressureVP 30/VP 44 fuel injection system Operation In the variable turbocharger the charging or boostpressure is controlled by adjusting the blades. Inthis way the optimum charging pressure can be setfor every operating state. When a control adjustment is required, the vanes ofthe variable turbocharger are adjusted by the boostpressure solenoid valve. The actual charging pressure is measured by meansof the manifold absolute pressure (MAP) sensor.The set value depends on the engine speed and thequantity of fuel injected and on the correctionfactors for the intake air temperature (IAT) andbarometric pressure (BARO). If the charging or boost pressure control malfunctions, the fuel metering is used to reduce the engine power output.

1 Boost pressure solenoid valve2 Manifold absolute pressure (MAP) sensor3 Intake air temperature (IAT) sensor4 Intercooler (not on all variants)5 Vacuum diaphragm unit for variable turbine geometry6 Turbocharger7 PCM8 Vacuum pumpDiagram shows charging pressure system of a turbocharger with variable turbine geometry

Glow plug controlVP 30/VP 44 fuel injection system Operation The PCM incorporates a glow plug control systemwhich is divided into two areas:Pre-heat The PCM receives the corresponding temperature signal from the CHT sensor.The preheat time is dependent on the temperature signal (low temperature = longer preheat time).Post-heat The post-heat phase follows the preheat operationafter the engine has been started. The post-heat operation reduces engine noise,improves idling and decreases the emission ofhydrocarbons (HC) through more efficientcombustion shortly after starting. The post-heat operation is carried on up to anengine speed of approximately 2500 rpm.Once the engine speed exceeds 2500 rpm, the postheat phase is stopped. This increases the servicelife of the glow plugs.

1 CHT signal2 CKP signal (engine speed)3 PCM4 Glowplug warning indicator5 Glow plug relay (in central junction box)6 Parallel fuses (each 50 A)7 Glow plugs

After the engine is stopped and at certainintervals of time while in use, this data istransferred to the EEPROM. To guarantee this,the power supply relay remains activated for 1.2seconds after the ignition is switched off (power latch). 1 PCM connector2 Microprocessor3 Random access memory (RAM)4 EEPROM

5 PATS6 Power supply relay7 Fuse8 BatteryPCM fault strategy With diesel engines the PCM uses the EEPROM to store diagnostic trouble codes (DTCs) and other data. The EEPROM is a non-volatile read only memory, which means that the data contained init is protected even if the power supply is cut (e.g. by disconnecting the battery). During a trip, all new diagnostic trouble codesand engine adaptation data (e.g. fuel adaptationdata) are initially stored in the random accessmemory (RAM) of the PCM. After the ignition is switched on, the DTCs stored in the EEPROM are copied to the random access memory (RAM) again.VP 30/VP 44 fuel injection system Operation Electronic Diagnostics

General Apart from knowledge of the principles ofelectronic diagnostics, good system knowledge andexperience of vehicle and system diagnostics areessential for conducting diagnostic checks.

The symbols shown in the graphics in this lesson (refer to the illustration) have the following meaning:1 Carry out visual checks and/or general checks(voltage or resistance checks).2 One or more diagnostic trouble codes is/arestored in the PCM.3 The preheat warning indicator is illuminated.4 Missing signal (controlled component inoperative)5 Faulty signal Before specific tests or one of the testroutines are conducted using the WDS, obviousfaults should be eliminated by conducting a visualcheck, for example:-- loose wiring connections,-- faulty fuses and relays-- severe contamination.-- faulty hoses and vacuum lines,-- blocked filters or air in the fuel system The WDS offers two different test methodsdepending on the vehicle:-- menu walker,-- tools.

Electronic Diagnostics

1 Example of reprogramming or programming a PCM anew2 Example of Non-specified tools test routine3 Example of datalogger in Specified tools test routine4 WDS portable test unit (PTU)5 Example of oscilloscope in Non-specified toolstest routine6 Example of digital mutlimeter in Non-specified tools test routine7 Data link connector (DLC) Worldwide diagnostic system (WDS)

Electronic Diagnostics

Fault pattern (examples) The results of faulty or missing PCU signals can be:-- engine misfires,-- poor engine power,-- loud combustion noise (hammering),-- increased exhaust emissions,-- diagnostic trouble codes are set and the preheat warning indicator is illuminated (e.g. in the event of the PCU monitoring signal being interrupted or missing),-- the engine may stop.1 CKP sensor2 PCM3 Divergent or missing PCU monitoring signal4 Faulty or missing CKP signal5 Disturbed exchange of data between PCM and PCU6 Rotation angle sensor7 Pump control unit (PCU)8 Air in low-pressure system9 Fuel supply10 VP 30/VP 44 fuel injection pump11 Fuel injection pump relay is tripped out

Electronic Diagnostics

Passive anti-theft system (PATS) When the ignition is switched on, the PATS LED must go out after three seconds (system OK). If the PATS LED starts to flash with a constant rapid frequency (4 Hz) after three seconds, there is a fault in the system. After one minute the LED emits a flashing code which indicates that PATS has intervened. The result is:-- the starter motor will not respond,-- no fuel injection can take place.Diagnostics Wrong key or disturbed radio connection betweenthe ignition key and the transceiver. Electrical connector connection not OK (loose contact),break in the wiring. PATS not programmed or programmed incorrectly. Fault pattern If there is a fault in the PATS, the engine cannot be started.1 PCM2 PATS LED3 Starter motor will not respond4 No fuel injection (common rail system)5 PATS transceiver6 Pump control unit (PCU)7 No fuel injection (VP 30/VP 44)8 VP 30/VP 44 fuel injection pump9 Ignition key10 Disturbed radio connection between ignition key and transceiver11 Injector driver module (IDM)

Electronic DiagnosticsFault pattern

Fault rectification Rectify the obvious causes of the concern found during the visual check before carrying out any further checks. Conduct the WDS test routine in conjunction with the flashing code index, fault finding chart and system checks using the current workshop literature.

When programming a new PATS, always check the vehicle battery voltage.

When the fuel injection pump (VP 30/VP 44) is changed, the PCU and the PCM must be matched to one another again with the aid of the WDS (configuration). If there is a fault in the PATS, the engine cannot be started.

Electronic Diagnostics

1 Disturbed PCM/PCU data exchange2 Check PCU electrical connector is secure3 Disturbed/interrupted signal transmission4 High-pressure solenoid valve5 Fuel injection timing solenoid valve6 Fuel injection timing device7 Rotation angle sensor signal to PCU disturbed8 Faulty input (sensor) signalsVP 30/VP 44 distributor-type fuel injection pumpCarry out a visual check. Check that the PCU electrical connector is seatedsecurely and free of corrosion. Check the wiring for short circuits and wiringbreaks. The exchange of data between the PCU and thePCM may be disturbed or interrupted. The period of the monitoring signal from the PCUto the PCM may not be correct or the monitoringsignal may be missing. Dirt and/or air in the fuel low-pressure system. Carry out the WDS test routine.NOTE: If for example the DTC P1608 is displayed during the WDS test routine and the PCU monitoring signal is different or missing (the preheat warning indicator is illuminated), this definitely does not indicate that the fuel injection pump is faulty and must be changed. The EEC V engine management system also uses this DTC when the fuel injection pump relay is tripped out for other reasons.

Electronic Diagnostics

Exhaust gas recirculation (EGR) system solenoid valve Malfunctions in the circuit of the solenoid valve and leaks or blockages in the vacuum system can lead to failure of the EGR system.Diagnostics Malfunctions in the circuit of the solenoid valve.Faulty or missing signal from the PCM due to disturbed sensor signals (MAF sensor or positionsensor in the EGR valve). Leaks or blockages in the vacuum system. EGR valve clogged with carbon deposits or corroded. Carry out the WDS test routine.6 Exhaust gas recirculation (EGR) valve7 Vacuum pump8 Position sensor in EGR valve9 EGR cooler (not on all variants)1 EGR solenoid valve2 Faulty/missing PCM/sensor signals3 Damaged/blocked vacuum lines4 MAF sensor (only with variable turbocharger)5 PCM Fault pattern The results of signal failure and failure of the solenoid valve can be:-- the EGR system is switched off,-- reduced engine power,-- increased black smoke,-- DTCs are set and the preheat warning Indicator is illuminated.

?