SPECIFICATIONS

MAIN FEATURES

The Bosch Motronic ME7.9.10 system with a motorised throttle, for dual fuel operation, belongs to the category of ignition systems which have built-in, timed and sequential electronic injection.

The control unit electronically manages the air flow rate at the rotation speed set by the electronic throttle, regulates the fuel injection so that the (air/fuel) ratio is always within optimum values, calculating the moment of ignition, in order to allow the smooth operation of the engine when the environmental parameters and loads applied vary.

The ignition system is static advance with a single coil with three outlets. The power modules are housed inside the control unit.

The self-adaptive engine management system can recognise the changes that take place in the engine. It compensates for them using the self-adaptive functions that correct the fuel mixture and air flow plans mapped in the control unit.

The system is configured to run on LPG as standard.

LPG-petrol switching can take place:

- by user command, activating the switch in the centre console;

- automatically when ordered by the engine management control unit if the LPG in the tank has run out (pressure in the cylinder less than 10 bar) or in recovery conditions when LPG operation is not advisable.

The engine always starts up on petrol (to maintain the efficiency of this fuel supply) before transferring automatically to LPG fuel after a few seconds (if the switch is set to LPG mode); it is therefore necessary to always have petrol in the tank.

It is also recommended to periodically use up the petrol in the tank (until the reserve warning light is lit), in order to prevent the fuel from ageing and possibly degrading.

The main system functions are as follows:

• injection time adjustment;

• ignition advance adjustment;

• cold starting control;

• enrichment check during acceleration;

• fuel cut-off during over-run;

• idle speed management (also dependent on the battery voltage);

• restriction of the maximum engine speed;

• control of combustion with oxygen sensor;

• petrol vapour recovery;

• fan control;

• switching the climate control system on/off;

• self-diagnosis;

• slider on-off control;

• continuous variable valve timing control;

• calculation of the vehicle speed;

• automatic management of engine starting;

• petrol operation;

• LPG operation;

• LPG cut out solenoid valve control;

• residual LPG pressure indication.

There is also a special function that manages the connection with the body computer via a two-way signal for the CAN line. This includes:

• engine temperature for instrument panel (output);

• battery voltage (output);

• engine rpm (output) for instrument panel;

• engine overheating warning light for instrument panel (output);

• engine oil pressure warning light for instrument panel (output);

• vehicle speed (output) + odometer (input/output);

• Alfa code anti-theft device (input/output);

• key status;

• consumption signal (output) for trip computer;

• fuel level signal (input)

OPERATION

Diagram of information entering/leaving the control unit

The following diagram shows the information entering/leaving the control unit.

1. Rpm and TDC sensor

2. Throttle control actuator and throttle position sensor

3. Knock sensor

4. timing sensor

5. Intake air temperature and pressure sensor

6. Engine coolant temperature sensor

7. Oxygen sensors

8. LPG pressure/temperature sensor

9. LPG/petrol switch

10. LPG level gauge

11. Fuel vapour cut out solenoid valve

12. Ignition coils

13. Phase transformer pilot solenoid

14. Diagnostic socket

15. Cut out solenoid valve on LPG pressure regulator

16. Petrol pump relay

17. Climate control system relay

18. Body Computer

19. injector control

20. Petrol injector enablement

21. LPG injector enablement

OPERATING LOGICS

PETROL OPERATION

In this operating mode there are no functional variations in relation to the basic system.

The ME7.9.10 electronic control unit does not alter its behaviour and the system management strategies are the same as for the basic version.

The specific elements for the LPG system do not interfere in any way with the basic system.

LPG OPERATION

The engine runs on LPG after starting which always takes place using petrol (obviously with the switch on LPG mode before starting).

The petrol pump is thus deactivated during LPG operation.

As well as managing all the engine management and ignition advance functions, the ME7.9.10 electronic control unit also manages the phased sequential LPG injection, the activation of the LPG cut-off solenoid valves and the deactivation of the petrol pump.

Injection takes place directly through the operation of the specific LPG system injectors.

The ignition advance values, in LPG operation mode, are calculated by applying a correction coefficient to the same values used for petrol operation.

The controls for petrol injectors, diagnosis and the petrol self-learning strategy are also disabled through the SDU (Smart Driver Unit) control unit petrol/LPG injector control. The other basic electronic control unit functions are carried out as usual and all the input signals remain the same. All the controls are implemented as usual (ignition, etc.).

The electronic control unit processes the information coming from the basic system sensors and the additional ones in order to recognize the system operating conditions and produce suitable commands for the LPG injectors.

The management strategies use typical curves and control parameters stored in the control unit memory. The calibration values are defined according to the performance, fuel consumption, emission and handling objectives.

SELF-LEARNING

The control unit implements the self-learning logic under the following conditions:

• removing-refitting or replacement of the injection control unit

• removing-refitting or replacing the throttle body

The values stored by the control unit are retained when the battery is disconnected.

SYSTEM SELF-ADJUSTMENT

The control unit is equipped with a self-adaption function that is designed to recognize the changes that take place in the engine due to the processes of bedding in over a period of time and ageing, both of components and engine itself.

These changes are stored in the form of modifications to the basic map and are designed to adapt the system operation to the gradual alterations in the engine and the components, compared with the characteristics of the new engine/components.

This self-adjustment function also makes it possible to compensate for the inevitable differences in any replacement components (owing to production tolerances).

From the analysis of the exhaust gases, the control unit modifies the basic map in relation to the specifications of the engine when new.

The following self-adaption strategies are provided in the control unit:

- mixture strength control multiplication coefficient; takes into account the mixture strength slips linked to the sensor differences, injectors, air chamber and continually updates while the engine is running.

- mixture strength control additive coefficient, corrects injector leaks and updates when idling.

The self-adjustment parameters are not deleted when the battery is disconnected.

SELF-DIAGNOSIS AND RECOVERY

The control unit auto-diagnostic system checks that the system is working correctly and signals any irregularities by means of an MIL warning light in the instrument panel with a standardised icon and colour, as laid down by European regulations.

This warning light indicates engine management faults and also faults detected by EOBD diagnosis strategies.

The MIL warning light operating logic is as follows.

The warning light comes on with the ignition on and remains on until the engine is started up; the control unit autodiagnostic system checks the signals coming from the sensors and compares them with the permitted data limits.

Indication of faults during engine starting:

• the failure of the warning light to go out when the engine has been started indicates that there is an error memorized in the control unit.

Indication of faults during operation:

• the warning light comes on in flashing mode to indicate possible catalytic converter damage due to misfiring.

• If the warning light comes on constantly, this indicates the engine management errors or EOBD diagnosis errors.

The control unit defines the recovery settings on each specific occasion according to which components are faulty.

The recovery parameters are managed by non-faulty components.

The recovery strategies that can be activated from the control unit are:

- limp home following throttle body error

- limp home following accelerator pedal error

- turbocharging; the throttle is closed when there is a rise in the turbocharging pressure during the transient stages of acceleration with the target pressure and the measured pressure differential greater than 200 mbar, while a turbocharging pressure limit is activated if there is an error with the accelerator pedal or throttle actuator.

European regulations require the EOBD system to use the following strategies relating to the engine subsystems that have a direct impact on emissions:

- fuel supply system (fuel system diagnosis), to detect any malfunctions on the fuel line.

- Oxygen sensor diagnosis to detect operating errors in the sensor upstream of the catalytic converter.

- catalytic converter diagnosis to detect deterioration via indirect measuring of the oxygen storage capacity.

- diagnosis relating to irregular ignition (misfire diagnosis) that stops the catalytic converter working correctly, potentially causing irreversible damage.

In the event of the failure of LPG system components, the control unit tries to manage alternative functions aimed at keeping the engine running for as long as possible. Only in the event of serious faults (e.g. with the LPG injectors), it automatically switches the system to petrol operating mode and switches on the LED on the switch.

SYSTEM CONTROLS AND MANAGEMENT

Alfa code recognition

The moment the control unit receives the "MAR-ON" signal, it communicates with the Body Computer to obtain start-up enablement.

The starter motor is controlled directly by the key and not by the control unit.

The communication takes place through the CAN line.

As in the last example, the W recovery line is not used again.

Cold start control

The following occurs in cold start conditions:

• a natural weakening of the mixture (as a result of the poor turbulence of the particles of fuel at low temperatures)

• the reduced evaporation of the fuel

• condensation of the fuel on the internal walls of the intake manifold

• greater viscosity of the lubricant oil.

The electronic control unit recognises this condition and corrects the basic injection time according to the:

• coolant temperature; this increase is greater for petrol operation and smaller for LPG operation.

• intake air temperature

• battery voltage

• engine rpm.

The ignition advance only depends on the engine coolant temperature and speed.

Below a threshold that can be calibrated (from approx. 15 °C to approx. -25 °C) the ignition is enabled in "multispark" mode.

This strategy, achieved by controlling the coils to obtain a quick series of sparks, facilitates combustion of the mixture.

The rotation speed decreases proportionally as the engine temperature increases until the nominal value is reached when the engine is warmed up.

Combustion control - oxygen sensors

In EOBD systems the oxygen sensors, which are all the same type, are fitted upstream of the catalytic converter system and downstream of the catalytic converter.

The pre-catalytic converter sensor controls 1st loop mixture strength (upstream sensor closed loop).

The post-catalytic converter sensor is used for the catalytic converter diagnosis and for a fine modulation of the 1st loop control parameters.

The second loop is therefore adaptive to make up for production discrepancies and slight drift that pre-catalytic converter sensor responses could experience due to ageing and contamination.

This control is known as 2nd loop control (post-catalytic converter sensor closed loop).

The control of the mixture strength in the first loop is activated when the pre-catalytic converter oxygen sensor is capable of providing an expected signal which takes place a while after the engine has been started.

Sensor activation time depends on the initial temperature of the engine.

Control of the second loop is activated with a much higher temperature than that of the first loop: if the control of the first loop takes place 80 seconds after the engine has been started, the control of the second loop takes place after 450 seconds.

Post-catalytic converter sensor voltage is around 630 mV and is constant (when it starts to fluctuate the converter is worn).

Detonation control

This control is maintained even when the engine is operating with LPG fuel supply.

The control unit detects the presence of detonation (engine knock) by processing the signal coming from the appropriate sensor.

The control unit continuously compares the signals coming from the sensor with a reference value which is, in turn, constantly updated in order to take into account background noise and the ageing of the engine.

The control unit is therefore capable of detecting the presence of detonation (or the onset of detonation) in each individual cylinder and reduces the ignition advance in the cylinder concerned (in steps of 3 degrees up to a maximum of 6 degrees) until the phenomenon has disappeared. Later on, the advance is gradually restored to the basic value (in steps of 0.8°).

In acceleration conditions, a higher threshold is used to take into account the increased noise of the engine under such circumstances.

The detonation control logic also has a self-adjustment function which memorises the reductions in the advance that are continuously repeated in order to adapt the map to the different conditions that may affect the engine.

Control of enrichment during acceleration

During this stage, the control unit suitably increases the amount of fuel supplied to the engine (to produce maximum torque) according to the signals coming from the following components:

• accelerator pedal potentiometer and throttle position.

• rpm and TDC sensor

The basic injection time is multiplied by a coefficient depending on the temperature of the engine coolant, the opening speed of the accelerator throttle and the increase in pressure in the intake manifold.

If sharp variation in the injection time is calculated when the injector is already closed, the control unit reopens the injector (extra pulse) in order to be able to adjust the mixture strength as quickly as possible; the subsequent injections are already increased on the basis of the coefficients mentioned previously.

ASR and VDC management requires the control unit to reduce the torque and therefore the ignition time together with action on the throttle and on the ignition advances.

Fuel supply - electric fuel pump check

The control unit supplies the electric pump:

• with the ignition ON for 0.8 secs.

• with the ignition in the starting position AVV and the engine speed > 20 rpm.

The control unit interrupts the supply to the electric pump:

• with key on STOP

• with the engine speed < 40 rpm.

The fuel supply system with recirculation ensures a constant pressure differential of 3.5 bar.

Connection to the climate control system

The climate control system is constantly managed by adding together the torque required by the user and the torque required for the operation of the compressor:

- when the total is less than the calibrated threshold, depending on the engine rpm, the user request is enabled;

- when the total is more than the calibrated threshold, depending on the engine rpm and the speed being below 10 km/h, the user request is not enabled.

The control unit momentarily interrupts the supply to the compressor:

• during starting

• switching it off when the engine temperature > 115 °C and reactivating it with a hysteresis of 5.3 °C.

• during take off with the accelerator pedal fully depressed.

Recognition of cylinder position

The engine timing signal, together with the engine rpm and TDC signal, allow the control unit to recognize the succession of cylinders to implement the timed injection.

This signal is produced by a Hall effect sensor, positioned on the cylinder head near the toothed wheel formed on the intake camshaft.

Fuel cut-off during deceleration

When the accelerator pedal is released and beyond a pre-set engine speed level, the control unit:

• cuts off the supply to the injectors

• reactivates the supply to the injectors at 1200 rpm in first gear and at 1000 rpm in other gears.

In the absence of fuel, the number of revs decreases at a rate determined by the vehicle driving conditions.

Before the idle speed is reached the progress of the engine speed decrease is checked.

If it is above a certain figure, the fuel supply is partly reactivated to ensure the “gentle accompaniment” of the engine to the idle speed.

The thresholds for restoring the fuel supply and the fuel cut-off vary according to:

• engine water temperature

• vehicle speed

• engine rpm.

Fuel vapour recovery

The (pollutant) fuel vapours, collected in an active charcoal filter (canister), are sent to the intake ducts to be burnt.

This takes place by means of a solenoid valve which is only operated by the control unit when the engine operating conditions allow it.

The control unit compensates for this additional amount of fuel with a reduction in the delivery to the injectors.

Maximum rpm control

The control of the maximum number of revs is carried out by the control unit, limiting the engine torque through the motorised throttle.

The first action the control unit takes is to cut off the supply of fuel adjusting the injection times and, if this is not sufficient, closing the motorised throttle.

The maximum number of revs for this version is 6350.

Injection time adjustment

The control unit calculates the injector opening time and controls them extremely quickly and precisely on the basis of the:

• engine load (rpm and air flow rate)

• battery voltage

• engine coolant temperature.

The air flow rate is calculated by taking into consideration the parameters recorded by the air temperature and pressure sensor fitted on the air chamber. Air pressure entering the throttle body and the ambient pressure via the sensor on the control unit are also corrective factors in the calculation of the flow.

The injection is the sequential, phased type for each cylinder and takes place at the optimum start of injection point whilst the end of injection point is fixed.

Ignition advance adjustment;

Thanks to a map stored in the control unit memory it is capable of calculating the ignition advance according to:

• the engine load (minimum, partial, full, according to the rpm and air flow rate)

• intake air temperature

• engine coolant temperature.

The ignition advance values, in LPG operation mode, are calculated by applying a correction coefficient to the same values used for petrol operation.

Idling speed control

The control unit detects idling status when the accelerator pedal is released.

To control the idle speed, depending on the consumers switched on and the brake/clutch pedal signals, the control unit controls the position of the motorised throttle.

The idling speed when warm is 750 ± 50 rpm.

On the basis of an electrical balancing strategy, the control unit increases the idle speed when the battery voltage is reduced to the calibrated threshold value.

Radiator cooling fan control

Depending on the temperature of the coolant, the control unit switches on the fan:

• 1st speed engagement temperature 97°C

• 2nd speed engagement temperature 102°C

There is then a further check (linear pressure sensor signal) which switches on the fan at the 1st or 2nd speed depending on the pressure of the refrigerant gas when the air conditioning system is switched on.

If there is no coolant temperature signal, the control unit implements the recovery function switching on the fan at the 2nd speed until the error disappears.

Torque control

The control unit for managing the various operating strategies is mainly based on control of engine torque.

There are two torque delivery rules:

- torque delivery with mechanical rule, for high engine loads, in practice when the measured throttle position is greater than the full load position (95% of load)

- torque delivery with controlled rule (this mode is used when mixture strength control is activated).

The control unit detects the torque request via the accelerator pedal and, after having made its calculations, adjusts the ignition advances, the throttle opening and the injection times.

There are three main tables for calculating the engine torque:

- low loads calculation table

- high loads calculation table

- reverse gear calculation table.

Car handling

The handling strategy includes three actions carried out by the control unit to make longitudinal fluctuations caused by the dynamics of the vehicle during transitions smoother and more gradual in order to make the use of the car as comfortable as possible.

Transitions refer to acceleration and deceleration of varying suddenness, due to the action on the accelerator pedal and gear changes.

The control unit detects the acceleration and deceleration transient stages through the accelerator sensor and the clutch and brake pedal switches, therefore intervening in torque management through the TIP-UP and TIP-DOWN calculation modules.

Depending on the situation, the control unit sets a fast torque control, adjusting the ignition advances and, if this is not enough, it activates a slow torque control adjusting the opening of the throttle and consequently the injection times.

Supercharging control

Turbocharger pressure management

The control unit controls the engine torque directly taking turbocharging into account, operating the waste gate valve directly to achieve the target pressure in the intake manifold depending on:

- engine load

- ambient pressure

- turbocharger pressure.

In particular, when the desired pressure reaches a calculated threshold, the control unit starts to adjust the exhaust gas flow through the waste gate. This introduces a feedback that guarantees system stability.

As well as the desired pressure, the power supplied to the compressor to achieve it is calculated. This power must be supplied from the turbine and therefore the exhaust gas flow is regulated to guarantee that this power is reached.

Shut-off solenoid valve management

In systems with a turbocharger, when the throttle is closed quickly (during release) overpressure is produced in the duct upstream of the throttle; this tends to slow the compressor impeller, leading to strong vibrations and noise.

The shut-off valve allows the recirculation of the air from downstream to upstream of the compressor, reducing the pressure in the manifold.

The control unit directly controls the shut-off valve depending on:

- engine load

- atmospheric pressure

- turbocharger pressure.

Cruise control

Depending on the position of the cruise control lever, the control unit directly manages the quantity of fuel injected in order to control and maintain the vehicle speed which has been memorised.

A warning light on the control panel, activated by the control unit, indicates system operation or deactivation status.

    See descriptions 5580A CRUISE CONTROL SYSTEM

Residual fuel level signal

The electronic control unit receives the signal from the level sensor fitted on the LPG tank. This information is then sent from the control unit to the indicator on the petrol/LPG switch.

Lpg injector operation

The operation of the LPG injectors is phased sequential type. The injector control timing varies according to the engine speed and the turbocharger air pressure.

Injector power supply occurs through the petrol/LPG injector control SDU (Smart Driver Unit): the engine management control unit calculates the injection time according to the specific situations.

The SDU control unit converts the injection time, calculated by the engine management control unit, into an electric control.

Lpg cut-out solenoid valve control

The LPG cut-out solenoid valves are operated by the engine management control unit through a relay switch.

The solenoid valves are closed if:

- the engine speed falls below approximately 50 rpm;

- after a certain time (about 3 seconds) with the key in the MAR position without the engine being started up (timed enablement);

- if there is an LPG - petrol switch;

- if the FPS (Fire Protection System) function has intervened.

The solenoid valves are opened:

- with the ignition switch in the MAR position for approx. 3 seconds;

- if there is a petrol - LPG switch.

ME 7.9.10 INJECTION-IGNITION CONTROL UNIT

Characteristics

The control unit is fitted in the engine compartment on the flame bulkhead.

The control unit memory is the flash EPROM type, i.e. it can be reprogrammed from the outside without operations to the hardware.

Replacement of the injection control unit or the throttle body requires the self-learning procedure to be run.

Control unit pin out

Engine side connector A

1, Oxygen sensor heater control (-) downstream of catalytic converter

2, Cylinder no. 3 injector control (-)

3, Fuel vapour solenoid valve control (-)

4, Cylinder no. 2 injector control (-)

5, Shut-off valve control (-)

6, SDU Cylinder 4 LPG injector control

7, SDU Cylinder 1 LPG injector control

8, SDU Cylinder 3 LPG injector control

9, +5V power supply for turbo pressure sensor; intake air pressure/temperature sensor; LPG pressure and temperature sensor

10, +5 V power supply for motorised throttle potentiometers

11, +5 V power supply for timing sensor

12, Timing sensor signal

13, Motorised throttle potentiometer reference earth

14, (-) LPG pressure temperature sensor

15, Not connected

16, Oxygen sensor heater control (-) upstream of catalytic converter

17, Cylinder no. 1 injector control (-)

18, Not connected

19, Cylinder no. 4 injector control (-)

20, SDU Cylinder 2 LPG injector control

21, Turbo pressure sensor signal

22, Motorised throttle potentiometer signal

23, Not connected

24, Intake air temperature signal

25, Intake air pressure signal

26, Not connected

27, Not connected

28, Timing sensor reference earth

29, Engine temperature sensor reference earth

30, Not connected

31, Ignition coil control cylinder 1

32, LPG pressure temperature sensor signal

33, Not connected

34, Not connected

35, Engine oil pressure switch

36, Detonation sensor earths

37, Rpm sensor (-)

38, Rpm sensor (+)

39, Not connected

40, Not connected

41, Not connected

42, Motorised throttle potentiometer signal

43, Engine temperature sensor signal

44, Turbo pressure sensor and air pressure/temperature sensor reference earth

45, Not connected

46, Ignition coil control cylinder 3

47, Ignition coil control cylinder 4

48, Ignition coil control cylinder 2

49, Motorised throttle actuator power supply (+)

50, Motorised throttle actuator power supply (-)

51, Detonation sensor signal

52, Oxygen sensor reference earth upstream of the catalytic converter

53, Oxygen sensor signal downstream of the catalytic converter

54, Oxygen sensor earth downstream of the catalytic converter

55, Oxygen sensor signal upstream of the catalytic converter

56, Not connected

57, Not connected

58, LPG temperature and pressure sensor earth

59, Not connected

60, Not connected

Vehicle side "K" connector

1, Engine system earth

2, Engine system earth

3, 12 V power supply from F17 (10 A)

4, Engine system earth

5, 12 V power supply from F17 (10 A)

6, 12 V power supply from F16 (5A)

7, Linear pressure sensor reference earth and LPG level sensor on tank

8, Not connected

9, Not connected

10, Not connected

11, Air conditioning compressor relay feed

12, Engine cooling fan high speed relay switch control

13, Engine cooling fan low speed relay switch control or

14, Not connected

15, Not connected

16, Not connected

17, Not connected

18, Not connected

19, Wastegate solenoid valve (-)

20, Not connected

21, Not connected

22, Not connected

23, Not connected

23, Not connected

24, Not connected

25, Not connected

26, Not connected

27, Accelerator pedal 2 potentiometer 5 V power supply

28, Linear pressure sensor 5 V power supply

29, Accelerator pedal 2 potentiometer reference earth

30, Accelerator pedal 1 potentiometer reference earth

31, LPG system solenoid valve relay switch

32, Not connected

33, Not connected

34, Not connected

35, Not connected

36, Not connected

37, Not connected

38, Not connected

39, Not connected

40, Not connected

41, Not connected

42, Not connected

43, Not connected

44, Not connected

45, Not connected

46, Not connected

47, Not connected

48, Not connected

49, Accelerator pedal 1 potentiometer 5 V power supply

50, Not connected

51, Not connected

52, Not connected

53, Not connected

54, Not connected

55, Signal from accelerator pedal 2 potentiometer

56, Not connected

57, Linear pressure sensor signal

58, Not connected

59, Not connected

60, Not connected

61, Clutch pedal switch

62, Petrol/LPG selector

63, Not connected

64, Not connected

65, Not connected

66, Not connected

67, Not connected

68, Fuel pump relay feed

69, Not connected

70, Positive supply from F18 (5A)

71, Petrol/LPG indicator

72, Engine management system main relay switch control (30A)

73, SDU relay switch (LPG injectors)

74, Not connected

75, Not connected

76, Not connected

77, Not connected

78, Not connected

79, Signal from accelerator pedal potentiometer 1

80, LPG level sensor on tank signal

81, Not connected

82, Not connected

83, Not connected

84, Reversing light switch

85, Not connected

86, Not connected

87, Brake light switch signal

88, C-CAN-L terminal CAN

89, C-CAN-H CAN

90, Not connected

91, Not connected

92, Not connected

93, Not connected

94, Not connected

"DNA" DYNAMIC CONTROL OF THE VEHICLE

The Alfa DNA system is a device that acts on the vehicle dynamic control systems and is electrically connected to the Body Computer which notifies the nodes involved of the configuration selected.

Instrument panel

The display shows specific information consistent with the mode selected.

VDC system

The VDC has three settings for each of the three Alfa DNA system positions (e.g.: in dynamic mode the intervention of the VDC is delayed to allow a more active driving style; in all weather mode braking on surfaces with differentiated grip is improved).

Steering

The steering is more or less stiff depending on the mode selected via the "DNA".

Suspension

Where fitted, the active suspension comply with the mode chosen via the DNA selector. For example, in dynamic mode it becomes stiffer, improving handling.

Gearbox

Where an automatic transmission is fitted, the gear change takes place at a higher engine speed and the Alfa DNA system also reduces the change time.

Operation

The "manettino" dial is a lever which always remains in the middle position. The configuration selected is recognized by the corresponding LED being lit up or the display in the control panel as illustrated below:

Dynamic display

All weather display

Normal display

No symbol is shown in the display for this configuration.

To turn “Dynamic” mode on, move the lever forwards (corresponding to the letter “D”), stay in this position for half a second until the LED lights up or the words “Dynamic on” appear in the control panel for a short time.

When the lever is released it will return to its middle position.

To return to “Normal” mode from “Dynamic” mode, repeat the same movement for the lever with the same time scales, but in this case the LED for the “Normal” position will light up and the control panel will show “Normal on” for a short time.

To engage “All weather” mode, move the lever backwards (to position “A”), stay in this position for half a second or until the LED lights up and the control panel shows “All weather on” for a short time.

The procedure to return to Normal is the same as the one described for Dynamic.

It is not possible to go directly from Dynamic mode to All Weather mode and vice versa. It is always necessary to return to the Normal mode.

If Dynamic mode was on before a key-off, then the configuration will automatically return to Normal mode at the next key-on.

If, on the other hand, the All weather or Normal mode was engaged, the configuration will be maintained at the next key-on.

The Dynamic mode can only be engaged at speeds below 110 km/h and remains on beyond this speed.

If there is a DNA system or selector failure, no configuration can be engaged and the message "mode not available" will be shown in the panel display.

INJECTORS

Characteristics

The twin jet injectors (with the spray inclined in relation to the injector axis) are specially designed for engines with 4 valves per cylinder and make it possible to direct the jets towards the two inlet valves.

The injectors are the top-feed type, i.e. fuel is fed in through the top of the casing, which also houses the electrical winding connected to the terminals of connector (3).

When the current passes through the winding, the magnetic field produced attracts the shutter causing the opening of the injector and the flow of fuel.

There are two seals, one on the fuel manifold side (1) and one on the intake manifold side (2).

A reference (4) determines the angular position of the injector and the correct direction of the jets in relation to the intake valves.

Inspection of the jets will show different openings, in total 10 divided into 2 sections of 5, in practice there are 10 small diffusion cones that together make 2 diffusion cones directed to the 2 intake valves.

Electrical specifications

The injector resistance can be measured by disconnecting the connector and connecting an ohmmeter as illustrated.

Resistance value: 14.5 ±5% ohm.

Electrical connections

Pin 1, +12V Power supply

Pin 2, Control to earth from control unit

Operation

The jets of fuel at a differential pressure of 3.5 bar come out of the injector and are instantly atomized forming two cones.

The injector operating logic is the sequential, phased type, in other words the four injectors are controlled in accordance with the engine cylinder inlet sequence whilst the supply can already commence for any cylinder in the expansion stroke until the inlet stroke has already started.

The amount of fuel injected depends on the shutter opening time which, in turn, depends on the solenoid supply time.

This time, known as the injection time, is calculated by the control unit in the different engine operating conditions.

FUEL MANIFOLD

The fuel manifold, which distributes the fuel to the injectors, incorporates the seats for the injectors and the differential pressure regulator.

The fuel supply and return are carried out through rapid attachment.

The pressure regulator ensures the right fuel supply pressure depending on the air chamber pressure.

1, Fuel manifold

2, Injector

3, Differential pressure regulator

4, Air pipe

5, Connector for fuel return rapid connector to the tank

6, Connector for fuel supply rapid connector

ENGINE COOLANT TEMPERATURE SENSOR

Characteristics

It is fitted on the thermostat and measures the temperature of the coolant by means of an NTC thermistor with a negative resistance coefficient.

The variation in the resistance depending on the temperature is illustrated in the table below.

Electrical specifications

- Power supply: 5V

- Maximum current: 2.5 mA

- Maximum power at 25 °C: 15 mV

Pin 1, Signal

Pin 2, Earth

Operation

The reference voltage for the NTC element for the injection system is 5 Volt, because the input circuit in the control unit has been designed as a tension divider, this voltage is divided between a resistance in the control unit and the sensor NTC resistance.

As a result, the control unit is capable of evaluating the sensor resistance variations by means of the changes in voltage and thereby obtaining temperature information.

Composition

The composition of the sensor is illustrated in the diagram below

1, NTC resistance

2, Sensor casing

3, Electrical connector

KNOCK SENSOR

Characteristics

The detonation sensor is the piezoelectric type and is fitted on the crankcase to detect the intensity of the vibrations caused by detonation in the combustion chambers.

The phenomenon produces a mechanical repercussion on a piezoelectric crystal that sends a signal to the control unit and, on the basis of this signal, the control unit reduces the ignition advance until the phenomenon disappears. Later on, the advance is gradually restored to the basic value.

Electrical specifications: resistance 4.9 MΩ ± 20%.

Electrical connections

Pin 1, Signal

Pin 2, Earth

Operation

The molecules of a quartz crystal are characterised by electrical polarisation.

In rest conditions (A) the molecules are not arranged in a particular way.

When the crystal is subjected to pressure or to an impact (B), the higher the pressure, the more marked their arrangement.

This arrangement produces a voltage at the ends of the crystal

A. Rest position

B. Position under pressure

RPM SENSOR

Characteristics

It is fitted on the crankcase front cover facing the phonic wheel built into the crankshaft pulley.

It is the inductive type, in other words it operates through the variation in the magnetic field produced when the flywheel teeth (60 – 2) pass by.

The injection control unit uses the RPM signal to:

• determining the rotation speed

• determining the angular position of the crankshaft.

Electrical specifications: resistance 1134 - 1386 Ω at 20°C.

The recommended distance (gap), between the end of the sensor and flywheel, to produce correct signals, should be between 0.5 and 1.5 mm.

Composition

The sensor consists of a tubular casing (1) containing a permanent magnet (3) and an electrical winding (2).

Operation

As a result of the passage of the wheel's tooth, the magnetic flow created by the magnet (3) fluctuates because of the variation in the gap.

These fluctuations set up an electromotive force in winding (2) and a voltage is set up at the terminals that alternates between positive (tooth facing sensor) and negative (gap facing sensor).

1, Sensor

2, Output signal

3, Signal corresponding to two missing teeth

4, Crankshaft pulley with phonic wheel

All things being equal, the peak sensor output voltage value depends on the distance between the sensor and the tooth (gap).

There are sixty teeth on the toothed wheel, two which have been removed to create a reference: the passage of the wheel therefore corresponds to an angle of 6° (360° divided by the 60 teeth).

The synchronism point is recognised at the end of the first tooth after the space for the two missing teeth: when it passes under the sensor, the pair of engine pistons 1-4 is at 114° before TDC.

Electrical connections

Pin A, Signal +

Pin B, Signal -

TIMING SENSOR

Characteristics

The Hall effect type sensor is used by the injection control unit in conjunction with the rpm and TDC signal to recognize the position of the cylinders and determine the injection and ignition point.

The timing sensor is located on the camshaft housing in the dedicated housing and is opposite the intake side camshaft.

A current-carrying semiconductor layer immersed in a normal magnetic field (force lines at right angles to current direction) generates a potential difference known as a Hall voltage at its terminals.

If current intensity remains constant, the generated voltage depends on magnetic field intensity alone.Periodic changes in magnetic field intensity are sufficient to generate a modulated electrical signal with frequency proportional to the speed of magnetic field change.

The distance between the sensor and the flywheel on the inlet cam axis is altered to produce this change and the reference mark for the timing is used in the process.

Electrical specifications

Supply voltage: 5V +/- 10%

Maximum voltage: 16 V

The sensor receives a direct power supply from the injection control unit.

Electrical connections

Pin 1, Earth

Pin 2, Signal

Pin 3, 5V power supply

ACCELERATOR PEDAL POTENTIOMETER

Characteristics

The accelerator pedal is equipped with two built-in potentiometers:

• one main one

• one safety one.

The injection control unit implements the following recovery strategies under the following conditions:

• if one of the two potentiometers fails, the control unit uses the remaining track without restricting the torque and checks the plausibility with the brake switch.

• if both potentiometers fail completely, throttle opening is prevented.

Operation

The sensor consists of a casing, fastened to the accelerator pedal support which contains a shaft connected to the twin track potentiometer in an axial position.

A coil spring on the shaft guarantees the correct resistance to pressure whilst a second spring ensures the return on release.

Electrical connections

Pin 1, 5V power supply potentiometer 2

Pin 2, 5V power supply potentiometer 1

Pin 3, Potentiometer earth 1

Pin 4, Potentiometer signal 1

Pin 5, Potentiometer earth 2

Pin 6, Potentiometer signal 2

THROTTLE BODY

Characteristics

It is fitted on the intake chamber and regulates the quantity of air drawn in by the engine.

Depending on the signal coming from the accelerator pedal potentiometer, the injection control unit controls the opening of the throttle by means of a direct current motor incorporated in the throttle casing.

The opening of the throttle takes place between 0° and 80° thereby including the adjustment of the idle speed.

The throttle body is equipped with two built-in potentiometers, each of which controls the other.

If there is a failure with the two potentiometers or a supply failure, depending on the position of the accelerator pedal, the control unit reduces the engine torque:

• fully depressed, it cuts off the supply to one or more pistons until a maximum speed of 2500 rpm is reached

• in the intermediate positions, it cuts off the supply to one or more pistons until a speed of below 1200 rpm is reached

The self-learning procedure must be carried out if the injection control unit or the throttle casing needs replacing.

Operation

The injection control unit operates the motorised throttle according to accelerator pedal requests; a potentiometer connected to it sends a voltage signal to the control unit where it is processed and opening laws are produced.

Electrical connections

Pin 1, Throttle opening motor earth

Pin 2, TPS1 and TPS2 potentiometer earth

Pin 3, TPS1 and TPS2 potentiometer 5V positive

Pin 4, Throttle opening motor positive

Pin 5, TPS2 potentiometer signal

Pin 6, TPS1 potentiometer signal

INTAKE AIR TEMPERATURE AND PRESSURE SENSOR

Characteristics

The intake air temperature and pressure sensor is an integrated component that has the function of measuring the pressure and the temperature of the air inside the intake manifold.

Both pieces of information are needed by the control unit to define the quantity of air drawn in by the engine; this information is then used to calculate the injection time and the ignition point.

The sensor is fitted to the air chamber.

Composition

The air temperature sensor is an NTC thermistor (Negative Temperature Coefficient). The resistance offered by the sensor decreases as the temperature increases.

The control unit intake circuit creates a division of the 5 V reference voltage between the sensor resistance and a fixed reference value, thereby producing a voltage that is proportional to the resistance and consequently to the temperature.

The sensitive element of the pressure sensor consists of a Wheatstone bridge etched on a ceramic diaphragm. On one side of the diaphragm the absolute reference vacuum is present, whilst the vacuum present in the intake manifold acts on the other side.

Before being sent to the engine management control unit, the (piezoresistive) signal from the distortion suffered by the diaphragm is amplified by an electronic circuit contained in the same support which houses the ceramic diaphragm.

When the engine is switched off, the diaphragm bends according to the value of the atmospheric pressure so that when the key is inserted exact altitude information is provided.

When the engine is running, the effect of the vacuum produces a mechanical effect on the sensor diaphragm which bends causing a variation in the resistance value.

Since the supply is kept strictly constant (5V) by the control unit, varying the value of the resistances alters the output voltage.

Electrical specifications

The electrical properties of the sensor are illustrated in the diagram below.

1, Air temperature sensor

2, Intake air pressure sensor

Electrical connections

Pin 1, Earth

Pin 2, Air temperature sensor signal

Pin 3, 5V power supply

Pin 4, Air pressure signal in intake manifolds

IGNITION COILS

Composition

The coils are connected directly to the spark plugs and are the "PLUG TOP" type comprising a magnetic internal core made up of a silicon steel pack arranged along the axis of the coil and secondary and primary coils which contain the electrical windings, coaxial to the magnetic core.

The windings are housed in a pressed plastic container which has the low voltage connector and the fastening bush on the cylinder head and they are insulated through immersion in an epoxide resin which has excellent dielectric, mechanical and also thermal properties, as the coils are exposed to high temperatures. The proximity of the primary winding to the magnetic core reduces magnetic flux losses thereby ensuring optimum coupling at the secondary winding.

The head of the coil is connected to the spark plug by means of a silicone rubber cap which contains a spring that transfers the secondary winding high tension to the spark plug terminal.

The coils are directly controlled by the injection control unit in sequential timed mode.

The control unit earths the primary coil power supply circuit thereby creating a strong magnetic field on the primary coil. When the primary circuit is open a high voltage is produced at the secondary circuit through induction.

The high tension is discharged to the engine earth via the spark plug electrodes producing the spark that ignites the air/fuel mixture.

Electrical specifications:

Primary circuit resistance: 0.53 Ω ± 5% at 23°C

Secondary circuit resistance: 8100 Ω ± 5% at 23°C.

Rated current at primary winding: 7.3 A

Voltage at secondary winding: 27 kW

Electrical connections

Pin 1, Connection to engine of engine secondary circuit

Pin 2, primary circuit +12 V power supply

Pin 3, Control to earth from primary circuit control unit

Vehicle speed sensor

Characteristics

The vehicle speed signal is produced by the ABS control unit and sent to the engine management control unit via the CAN.

TURBO PRESSURE SENSOR

Characteristics

The turbo pressure sensor comprises a Wheatstone bridge serigraphed on a ceramic diaphragm and is used by the control unit for measuring the supercharging pressure downstream of the intercooler.

The sensor is fitted to the rigid intake pipe located before the motorised throttle valve.

The control unit uses the signal coming from the sensor to manage the supercharging pressure and to calculate the mass of air required for the subsequent fuel metering.

Pin 1, 5V power supply

Pin 2, Earth signal

Pin 3, Turbo pressure signal

SHUT-OFF SOLENOID VALVE

Characteristics

It is a by-pass valve that includes a solenoid type on/off valve electrically controlled by the control unit.

The shut-off solenoid valve makes it possible to restrict excess pressure in the duct downstream of the compressor through the rapid closing of the throttle following a deceleration manoeuvre.

This excess pressure can cause the turbocharger impeller to slow down, causing a loss of performance and harsh vibrations and noise.

The shut-off solenoid valve is fitted on a dedicated bracket near the throttle body.

Operation

The solenoid valve comprises a casing enclosing a mechanical diaphragm valve (1) with a return spring (2) and an electromagnet (3) supplied by the injection control unit.

During overrun the injection control unit supplies the electromagnet (3) which attracts the mechanical valve (1) which opens a by-pass and discharges the excess intake pipe pressure upstream of the turbocharger.

Electrical specifications

Supply voltage: 12 V

Operating voltage: 8 V - 16 V

Current absorption: 1.4 A (at 13 V and 25°C)

Electrical connections

Pin 1, +12V Power supply

Pin 2, Control to earth from injection control unit

WASTEGATE SOLENOID VALVE

Characteristics

The waste gate solenoid valve is used by the injection control unit to manage the turbo pressure through direct action via pneumatic connections with an actuator on the turbocharger.

1. Solenoid valve

2. Actuator

3. Wastegate valve

The solenoid valve comprises a plastic casing that encloses a shutter and an electromagnet.

It is connected, via flexible pipes, to:

- turbocharger outlet (high pressure intake)

- wastegate valve actuator

- turbocharger air intake pipe (excess air pressure discharge).

The injection control unit measures the supercharging pressure in all engine operating ranges through the turbo pressure sensor. If this pressure exceeds the pre-set values, the control unit intervenes on the solenoid valve supplying the electromagnet which, attracting a shutter, releases the high pressure flow to the actuator thereby allowing the wastegate valve to open.

Once the regulation action is over, the electromagnet is no longer supplied and the high pressure is discharged upstream of the turbocharger.

Electrical specifications

Electromagnet winding resistance: 30 ohm +/- 10% at 20°C

Electrical connections

Pin 1, Control to earth from control unit

Pin 2, +12V Power supply

BRAKE PEDAL SWITCH

The dual stage brake pedal switch is used by the Engine Management Node to manage the strategies linked to driveability.

The brake pedal switch (1) is fitted on the pedal unit support as illustrated.

Specifications and operation

The brake pedal switch contains two switches, one normally open (N.A.) type and one normally closed (N.C.) type.

During operation, the (N.A.) switch closes, whilst the (N.C.) one opens, therefore the (N.C.) switch is designed to recognize the brake pedal in the rest position, whilst the (N.A.) switch is designed to recognize the brake pedal pressed.

The diagram below illustrates the internal electrical circuit with the brake pedal pressed and the operating diagram.

A. Power supply positive

B. Electrical consumer power supply

C - D. Redundant control switch

P. Brake pedal pressed status

R. Brake pedal released status

Both switches are closed in the halfway position, a situation used to check the consistency of the signal for the two switches.

CLUTCH PEDAL SWITCH

The clutch pedal switch is used by the Engine Management Node to manage the strategies linked to driveability.

The clutch pedal switch (1) is fitted on the pedal unit support as illustrated.

The switch comprises a casing that contains an (N.O.) switch which closes on a sliding track when the pedal is pressed.

1. Connector

2. Outer lever with drive pin lock

3. Fastening tooth

4. Fastening lever

Electrical connections

Pin 1. Frame earth connection

Pin 2. Not connected

Pin 3. Switch signal