sequential, phased type electronic injection (1-2-4-5-3).
The Engine Management Node controls:
the air flow rate whilst idling set via the electronic throttle;
the moment of ignition with the advantage of the engine running smoothly as the environmental parameters and loads applied vary.
The Engine Management Node controls and manages the injection so that the air/fuel ratio is always very close to the stoichiometric value in order to ensure maximum conversion efficiency for the catalyzer; in full power and high usage conditions the mixture is enirched to guarantee maximum performance.The main functions of the system are basically as follows:
self-learning;
system self-adjustment;
self-diagnosis;
CODE recognition;
cold starting check;
combustion - Lambda sensor check
check on phase transformer and modular intake manifold;
knock control;
check on enrichment during acceleration;
fuel cut-off when accelerator pedal is released;
fuel vapour recovery;
maximum rpm check;
fuel supply - electric fuel pump check;
connection with climate control system;
recognition of cylinder position;
injection time adjustment;
ignition advance adjustment;
idle speed check;
control of engine cooling fan;
connection with automatic transmission control unit (where fitted);
connection with ABS control unit;
connection with control panel.
fuel system fault diagnosis;
catalyzer fault diagnosis.
Lambda sensor fault diagnosis.
misfire fault diagnosis
VIEW OF ASSEMBLY.
DIAGRAM SHOWING INFORMATION ENTERING/LEAVING ENGINE MANAGEMENT NODE.
OPERATION
Operating strategies
General remarks
Injection systemThe following conditions are essential and must always be satisfied during the preparation of the air/fuel mixture for the smooth operation of ignition controlled engines:
the "metering" (air/fuel ratio) must be kept as close as possible to the stoichiometric value to ensure the maximum conversion capacity of the catalytic converters (max. efficiency).
the "homogoneity" of the mixture, composed of petrol dispersed in the air as finely and evenly as possible.
The information that the Engine Management Node processes for optimum metering is received via electrical signals transmitted by the:
air flow meter and air temperature sensor for the exact quantity of intake air.
rpm sensor which produces an alternating, single phase signal whose frequency indicates the engine speed. This signal is used by the Engine Management Node for detecting misfire.
throttle potentiometer to recognize the acceleration conditions requested.
coolant temperature sensor located on the thermostat.
Lambda sensors to determine the oxygen content of the exhaust gases and, via the downstream sensor, to diagnose the efficiency of the catalyzers.
Ignition system.The ignition system is the static advance, inductive discharge type (i.e. with no high tension distributor) with power modules located inside the Engine Management Node.In this ignition system each coil supplies the spark plugs for the appropriate cylinder.The advantages of this solution are:
less electrical overload;
guaranteed constant discharge at each spark plug.
A map is stored in the Engine Management Node memory which contains the series of optimum ignition advance values (for the cylinder in the explosion stroke) which the engine can adopt according to the engine load and speed conditions.The Engine Management Node makes corrections to the advance value mainly according to the:
engine coolant temperature.
intake air temperature.
detonation.
throttle valve position.
The information that the Engine Management Node processes to operate the coils is received via electrical signals transmitted by the:
air flow meter with built in air temperature sensor for the exact quantity of intake air.
rpm sensor which produces an alternating, single phase signal whose frequency indicates the engine speed.
2 detonation sensors (at the rear of the cylinder block/crankcase, one between the 1st and 2nd cylinders, the other between the 4th and 5th) to recognize which cylinder detonation is taking place in and therefore correct the ignition advance.
throttle position potentiometer to recognize minimum load, partial load and full gas conditions.
timing sensor.
Self-learning.
The Engine Management Node implements the self-learning logic in the following conditions:removing-refitting or replacing the Engine Management Node.removing-refitting or replacing the throttle casing.The values memorized by the Engine Management Node are preserved if the battery is disconnected.
System self-adjustment.
The Engine Management Node is equipped with a self-adjustment function that is designed to recognize the changes that take place in the engine due to the processes of bedding in and ageing of both the components and the engine itself in time.These changes are memorized in the form of modifications to the basic map and are designed to adapt the operation of the system to the gradual alterations in the engine and the components compared with when they were new.This self-adjustment function also makes it possible to compensate for the inevitable differences in any replacement components (due to production tolerances).From the analysis of the exhaust gases, the Engine Management Node modifies the basic map in relation to the specifications of the engine when new.The self-adjustment parameters are not cancelled if the battery is disconnected.
Self-diagnosis
The Engine Management Node checks that the system is working properly and signals any irregularities by means of an MIL warning light in the instrument panel with a standardized ideogram and colour laid down by European regulations. This warning light signals both engine management faults and defects detected by the EOBD strategies.The MIL warning light operating logic is as follows:
with the ignition on, the warning light comes on and remains on until the engine has been started up. The Engine Management Node autodiagnostic system checks the signals coming from the sensors comparing them with the permitted limits:
Siganalling of faults during stating:
the failure of the warning light to go out when the engine has been started indicates that there is an error memorized in the Engine Management Node.
Signalling of faults during operation:
the warning light flashing indicates possible damage to the catalyzer through the presence of misfire.
the warning light coming on constantly indicates the presence of engine management errors or EOBD errors.
RECOVERYFrom time to time the Engine Management Node defines the type of recovery according to the components that are faulty. The recovery parameters are managed by components that are not faulty.
CODE recognition
The moment the Body Computer receives the ignition ON signal, it converses with the Engine Management Node to allow starting. For vehicles equipped with Passive Entry see {DF55].
Cold starting check.
The following occurs in cold starting conditions:
a natural weakening of the mixture which causes poor evaporation (poor turbulence of the particles of fuel at low temperatures).
reduced evaporation of the fuel.
condensation of the fuel on the inner walls of the intake manifold.
increased viscosity of the lubrication oil.
The Engine Management Node recognizes this condition and corrects the basic injection time:
coolant temperature.
intake air temperature.
battery voltage.
engine speed.
The ignition advance only depends on the number of revs and the temperature of the engine coolant.Whilst the engine is warming up, the Engine Management Node operates the motorized throttle to regulate the quantity of air required to ensure that the engine does not cut out.The rotation speed decreases proportionally as the engine temperature increases until the nominal value is reached when the engine has warmed up.
Combustion - Lambda sensor check.
In EOBD systems, the Lambda sensors, which are all the same type, are located upstream of the catalyzer system and downstream of the catalyzer. The upstream sensor determines the control of the mixture strength known as the 1st closed loop for the upstream sensor. The sensor downstream of the catalyzer is used for the fault diagnosis of the catalyzer and for modulating the 1st loop control parameters. The adaptation of the second loop is designed to recover both production dispersions and the slight deviations in the response of the upstream sensors as a result of ageing or pollution. This control is known as the 2nd closed loop of the downstream sensor).
Check on phase transformer and modular intake manifoldIn order to ensure the optimum quantity of air introduced by the engine, the Engine Management Node controls:
the intake timing in two angular positions.
the geometry of the intake manifolds in two lengths.
The Engine Management Node sets the "open" stage at the maximum torque speed:
cam advance of 18° engine.
intake chamber long ducts.
The Engine Management Node sets the "closed" stage at the maximum power speed and the minimum speed:
cam in normal position.
intake chamber short ducts.
In the other engine operating conditions, the Engine Management Node selects the most suitable configuration for optimum performance, consumption and emissions.In the release stage the chamber intake ducts are always short. In the release stage the chamber intake ducts are always short.
Knock control.
The Engine Management Node detects the presence of detonation (engine knock) by processing the signal coming from the relevant sensors.The Engine Management Node continuously compares the signals coming from the sensors with a threshold which is, in turn, continually updated to take into account background noise and engine ageing.The Engine Management Node 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 involved (in steps of 3° up to a maximum of 6°) until the phenomenon disappears. 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 in these circumstances.The detonation control logic also has a self-adjustment function which memorizes the reductions in the advance that are continuously repeated in order to adapt the map to the different conditions that the engine finds itself in.
Check on enrichment during acceleration.
If the variation in the air flow meter signal exceeds a pre-defined increase during an acceleration request, the Engine Management Node increases the injection (injection time) in order to reach the required number of revs rapidly.Recovery:the Engine Management Node replaces the signal coming from the air flow meter which is
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