3308467 - 1056B multi-point injection system (mpi) (Automatic transmission)

VIEW OF ASSEMBLY

GENERAL CHARACTERISTICS

Operation of the fuel injection-ignition

The Bosch Motronic ME2.1 system with a motorized butterfly belongs to the category of integrated systems with:

• ignition
• sequential and timed electronic injection.

The main operating principles of the sytem are basically as follows:

• self-learning;
• system self-adaptation;
• autodiagnosis;
• recognition of the Alfa Romeo CODE (Immobilizer);
• control of cold starting;
• control of combustion - Lambda sensor;
• control of detonation;
• control of mixture enrichment during acceleration;
• fuel cut-off with accelerator pedal released;
• fuel vapour recovery;
• control of the maximum rpm;
• control of the fuel pump;
• connection to the climate control system;
• recognition of cylinder position;
• control of optimum injection time for each cylinder;
• adjustment of ignition advance values;
• management of idle speed (also according to the battery voltage);
• management of the butterfly opening law (Sport throttle response);
• control of the electric fans;
• control of the Cruise Control system (where fitted)
• connection with the ABS control unit;
• connection with the automatic transmission control unit (where fitted);
• conection with the instrument panel.

Fuel injection system

The essential conditions that must always be met in the preparation of the air-fuel mixture for the correct operation of controlled-ignition engines are mainly:

• the "metering" (air/fuel ratio) should constantly be kept as close as possible to the stoichiometric ratio, so as to ensure the maximum conversion capacity for the catalytic converter (max. efficiency).
• the "homogeneity" of the mixture, consisting of petrol, diffused as finely and evenly as possible in the air.

The information processed by the control unit for controlling optimum metering is received in the form of electrical signals emitted by the:

• air flow meter and air temperature sensor, for the exact quantity of air drawn in
• rpm sensor, which generates an alternating single-phase signal whose frequency indicates the engine rpm
• butterfly potentiometer, to recognize the acceleration conditions requested
• coolant temperature sensor located on the thermostat
• Lambda sensor for determining the oxygen content in the exhaust gases.

Ignition system

The system has a single coil for each plug (MONOCOIL); the advantages of this solution are:

• less electrical overload;
• guaranteed constant discharge on each plug.

The control unit corrects the advance values mainly in accordance with the:

• engine coolant temperature
• intake air temperature
• detonation.

The information the control unit processes in order to drive the single coils is received in the form of electrical signals emitted by the:

• air flow meter and air temperature sensor, for the exact quantity of air drawn in
• rpm sensor, which generates an alternating single-phase signal whose frequency indicates the engine rpm
• detonation sensors (on the upper part of the cylinder block/crankcase between the two heads) to recognize the cylinder where detonation is occurring and correct the ignition advance
• butterfly potentiometer, to recognize the minimum, partial and full load conditions
• timing sensor.

OPERATION

Diagram of input/output information to/from the control unit

SYSTEM OPERATING LOGICS

Self-learning

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

• removing-refitting or replacement of the injection control unit
• removing-refitting or replacement of the butterfly casing integrated with D.V.L.

System self-adaptation

Autodiagnosis

The control unit's self-test checks the signals coming from the sensors, comparing them with the permitted limits:

• indication of starting faults
• warning light on for 4 secs indicates test stage
• warning light off after 4 secs indicates no faults in components that could affect the values established in emission control regulations
• warning light on after 4 secs indicates fault
• fault indication during operation
• warning light on indicates fault
• warning light off indicates no faults in components that could affect the values established in emission control regulations
• recovery
• the control unit defines as and when required the type of recovery depending on the faulty components
• the recovery parameters are managed by non-faulty components.

Recognition of the alfa romeo code

Check on cold starting

The following occurs during cold starting:

• natural weakening of the mixture because of poor turbulence of the fuel particles at low temperatures
• condensation of the fuel on the inner walls of the inlet manifold
• higher viscosity of the lubricating oil.

The electronic control unit recognizes this condition and corrects the fuel injection times in accordance with:

• coolant temperature
• intake air temperature
• battery voltage
• engine rpm

Check on combustion - lambda sensor

Control of detonation

The control unit can delay the ignition selectively at the cylinder required, according to the combination of figures received from the detonation and timing sensors and:

• reduces the ignition advance in steps of 3° up to a maximum of 9°
• updates the threshold value to take into account:
• background noise;
• ageing of the engine.

With the auto-adjustment function, the control unit:

• memorizes the various advance reductions, continuously repeated;
• adapts the map to the different engine conditions.

Recovery:

• in the case of fault with the timing sensor or the detonation sensor or the injection control unit, the ignition is delayed according to the engine temperature and speed. The maximum ignition delay is always below 9° engine.

Control of the mixture enrichment during acceleration

Recovery:

• the control unit replaces the signal coming from the faulty air flow meter with the signal from the potentiometer integrated in the butterfly casing integrated with D.V.L.

Fuel cut-off with the accelerator pedal released

The control unit, in the following conditions:

• recognition of idle condition
• engine speed above a certain threshold

de-activates the fuel injection according to the:

• number of revs
• engine temperature
• vehicle speed.

Fuel vapour recovery

Control of the maximum rpm

Depending on the rpm reached by the engine, the control unit:

• over 6800 rpm cuts off the supply to the injectors (it is allowed to reach a maximum of 7000 rpm for a maximum of 5 secs).
• below 6600 rpm it restores the operation of the injectors.

Control of fuel pump

The con

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CONSTRUCTION FEATURES

View of assembly

1, Electric fuel pump 2, Relays 3, Lambda sensors downstream of catalyzer 4, Lambda sensors upstream of pre-catalyzer 5, Rev counter 6, Speedometer 7, Injection warning light 8, Timing sensor 9, Climate control connector 10, Diagnostic connector 11, Alfa Romeo CODE connector 12, Injection/ignition control unit 13, Injectors 14, Coolant temperature sensor 15, Rpm sensor 16, Air flow meter with air temperature sensor 17, Ignition coils 18, Detonation sensors 19, Fuel vapour recirculation solenoid valve 20, Accelerator pedal potentiometer 21, Clutch pedal switch 22, Brake pedal switch 23, Throttle body actuator integrated with D.V.L. 24, Cruise control 25, CAN line

GENERAL CHARACTERISTICS

Operation of the injection/ignition system

The Bosch Motronic ME3.1 system with a motorized throttle belongs to the category of integrated systems with:

• ignition
• sequential and phased electronic injection.
The control unit controls the air flow rate at the rotation speed set through the electronic throttle.The control unit controls the moment of ignition with the advantage of keeping the engine running smoothly as the ambient parameters and loads applied vary.The control unit controls and manages the injection so that the air/fuel ratio is always sufficiently close to the stoichiometric value to maximize the conversion efficiency of the catalyzers. In full power and high usage conditions, the mixture is enriched to guarantee maximum performance.

The main operating principles of the sytem are basically as follows:

• self-learning;
• system self-adaptation;
• autodiagnosis;
• recognition of the Alfa Romeo CODE (Immobilizer);
• control of cold starting;
• control of combustion - Lambda sensor;
• control of knock;
• control of mixture enrichment during acceleration;
• fuel cut-off with the accelerator pedal released;
• fuel vapour recovery;
• control of the maximum rpm;
• control of the fuel pump;
• connection to the climate control system
• recognition of cylinder position;
• control of the optimum injection time for each cylinder;
• adjustment of ignition advance values;
• management of the idle speed (also according to the battery voltage);
• control of the electric fans;
• control of the Cruise Control system (where fitted);
• connection with ABS control unit;
• connection with the automatic transmission control unit (where fitted);
• connection with the instrument panel;
• fuel system diagnosis;
• catalyzer diagnosis;
• detection of misfire;
• Lambda sensors diagnosis.
Fuel injection system

The essential conditions that must always be met in the preparation of the air-fuel mixture for the correct operation of controlled-ignition engines are mainly:

• the 'metering' (air/fuel ratio) should constantly be kept as close as possible to the stoichiometric ratio, so as to ensure the maximum conversion capacity for the catalytic converter (max. efficiency).
• the 'homogeneity' of the mixture, consisting of petrol, diffused as finely and evenly as possible in the air.

The information processed by the control unit for controlling optimum metering is received in the form of electrical signals emitted by:

• air flow meter and air temperature sensor, for the exact quantity of air drawn in
• rpm sensor, which generates an alternating single-phase signal whose frequency indicates the engine rpm
• throttle potentiometer, to recognize the driver conditions requested
• coolant temperature sensor located on the thermostat
• Lambda sensors for determining the oxygen content of the exhaust gases.
There are two Lambda sensors in the exhaust system at the intake for the pre-catalyzers.There are also two other Lambda sensors, downstream of the catalyzers, for determining the efficiency of the catalyzers and for correcting the injection times for the two main bearings in order to always guarantee maximum conversion efficiency of the catalyzers over a period of time.Ignition systemThe ignition is of the inductive discharge type, distributorless, with power modules located in the fuel injection control unit.

The system has a single coil for each plug (MONOCOIL); the advantages of this solution are:

• less electrical overload;
• guarantee of constant discharge at each spark plug.
Stored in the control unit, there is a map containing the entire set of optimum ignition advance values (for the cylinder at the power stroke) that the engine can adopt in relation to the rpm and required engine load.

The control unit corrects the advance values mainly in accordance with:

• engine coolant temperature
• intake air temperature
• detonation.

The information which the control unit processes to operate the ignition coils is received by means of electrical signals emitted by the:

• air flow meter and air temperature sensor, for the exact quantity of air drawn in
• rpm sensor, which generates an alternating single-phase signal whose frequency indicates the engine rpm
• detonation sensors (on the upper part of the cylinder block/crankcase between the two heads) to recognize the cylinder where detonation is occurring and correct the ignition advance
• throttle potentiometer, to recognize the minimum, partial and full load conditions
• timing sensor.
The control unit uses the rpm signal to recognize any misfire which could damage the catalyzers.

OPERATION

Diagram of input/output info to/from control unit

1, Electric fuel pump 2, Air conditioner compressor 3, Electric fan 4, Lambda sensors upstream of the pre-catalyzers 5, Cruise control 6, Quadrinary 7, Brake/clutch pedal switch 8, Timing sensor 9, Speedometer 10, Lambda senors downstream of the catalyzers 11, Coolant temperature sensor 12, Detonation sensors 13, Rpm sensor 14, Accelerator pedal potentiometer 15, Air flow meter with air temperature sensor 16, Battery 17, Butterfly casing integrated with D.V.L. 18, CAN line (for communication with ABS/ASR and automatic transmission control units) 19, Alfa Romeo CODE 20, Tester connection 21, Fuel vapour recirculation solenoid 22, Ignition coils 23, Injection warning light 24, Rev counter 25, Injectors

System operating modes

Self-learning

The control unit implements the self-learning mode in the following conditions:

• removing-refitting or replacement of the injection control unit
• removing-refitting or replacement of the throttle body integrated with D.V.L.
• removing-refitting or replacement of the rpm sensor/flywheel for recognizing misfire.
The values memorized by the control unit are preserved if the battery is disconnected.

System self-adaptionThe control unit has a self-adaption function which recognizes changes in the engine which occur as a result of bedding-in and ageing processes of both components and the engine itself.There are two adaptation functions according to two intervention plans: minimum and usage.

Self-testingThe control unit autodiagnostic system controls the correct operation of the system and signals any faults by means of an (MIL) warning light in the instrument panel which has a standardized European colour and ideogram. This warning light signals both engine management faults and problems detected by the EOBD strategies.

The (MIL) warning light operating logic is as follows:

• with the ignition key in the ON position, the warning light comes on and remains on until the engine has been started up. The control unit's self-test checks the signals coming from the sensors, comparing them with the permitted limits:

Signalling of faults during engine starting:

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

Fault indication during operation

• the warning light flashing indicates possible damage to the catalyzer due to misfire.
• the warning light on constantly indicates the presence of engine management errors or EOBD errors.
RECOVERYFrom time to time, the control unit defines the type of recovery according to the components which are faulty. The recovery parameters are managed by those components which are not faulty.

For some markets the warning light is read (rather than amber) and the EOBD is not active, and the warning light only signals faults in the fuel injection system as in the preceding versions. This is achieved with a specific engine management control unit (not interchangeable with the others) with modified software so as not to have the EOBD function.


Recognition of the alfa romeo codeWhen the control unit receives the ignition 'ON' signal, it communicates with the Alfa Romeo CODE control unit to obtain starting enablement.

Control of cold starting;

In cold starting conditions there is a natural weakening of the mixture which causes poor evaporation of the fuel at low temperatures:

• condensation of the fuel on the inner walls of the inlet manifold
• increased viscosity of the lubricant oil.

The electronic control unit recognizes this condition and corrects the fuel injection time in accordance with:

• coolant temperature
• intake air temperature
• battery voltage
• engine rpm.
The ignition advance depends solely on the engine rpm and the coolant temperature.During starting, the control unit controls a first simultaneous injection for all the injectors (full-group injection) and, after recognizing the timing of the cylinders, it starts normal sequential phased operation.Whilst the engine is warming up, the control unit operates the throttle body integrated with D.V.L. to regulate the quantity of air required to ensure that the engine does not cut out.The rpm is made to decrease as the temperature of the engine increases until the optimum value with the engine warmed up is obtained.

Check on combustion - lambda probeIn EOBD systems the Lambda sensors, which are all the same type, are located upstream of the catalyzer and downstream of the catalyzer. The upstream sensors carry out the check on the mixture strength known as the 1st loop (upstream sensor closed loop). The sensors downstream of the catalyzer are used for the catalyzer diagnosis and for finely modulating the 1st loop control parameters. With this in mind, the adjustment of the second loop is designed to recover both production differences and those in the response of the upstream sensors which may occur as a result of ageing and pollution. This control is known as the 2nd loop (downstream sensor closed loop).

Knock control

The control unit can delay the ignition selectively at the cylinder required, according to the combination of figures received from the detonation and timing sensors and:

• reduces the ignition advance in steps of 3° up to a maximum of 9°
• updates the level to take into account background noise and ageing of the engine.
During acceleration, the control unit uses a higher threshold for the increased engine noise.When the detonation disappears, the control unit increases the ignition advance in steps of 0.75° until it is completely recovered.

With the auto-adjustment function, the control unit:

• memorizes the various advance reductions, continuously repeated;
• adapts the map to the different engine conditions.
RECOVERYIn the case of fault with the timing sensor or the detonation sensor or the injection control unit, the ignition is delayed according to the engine temperature and speed. The maximum ignition delay is always below 9° engine.

Control of mixture enrichment during acceleration;When there is a considerable acceleration request, the control unit modifies the injection time and the position of the butterfly.RECOVERYThe control unit replaces the signal coming from the faulty air flow meter with the signal from the potentiometer integrated in the throttle body integrated with D.V.L.

Fuel cut-off with the accelerator pedal released

The control unit with:

• recognition of idle condition
• engine speed above a certain threshold

de-activates the fuel injection according to the:

• engine rpm
• engine temperature
• vehicle speed.
Before reaching the idle condition, the dynamics of the engine speed decrease are checked.If they exceed a certain value, the fuel supply is partly reactivated on the basis of a logic which makes provision for the 'gentle accompaniment' of the engine whilst idling.

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