194002112 - INTRODUCTION - PETROL FUEL INJECTION SYSTEM
SPECIFICATIONS
Four cylinder in line engine, ignition management with lost spark, 16 valves, twin overhead camshaft, counter-balance shafts, motorized throttle body; equipped with Motorola E16 injection system with PCB technology control unit.The unit is a system made up of the engine and all circuits required for its operation:- fuel supply system- air supply system- engine cooling system- exhaust system with catalytic converter built into the exhaust manifold- fuel vapour recirculation system.The operation of these systems is optimised by an electronic control system governed by a control unit.Operation of the injection-ignition system
The Motorola E16 system with a motorized throttle manages the sequential, phased type electronic injection and ignition function.The control unit controls the air flow rate at the idling speed set by the electronic throttle.The control unit controls the ignition time, with the benefit of maintaining smooth engine operation even when environmental and applied load parameters and engine operating conditions change.The control unit controls and manages the injection so that the air/fuel ratio is always close to the stoichiometric ratio to ensure maximum conversion efficiency for the catalytic converter.The main system functions are essentially as follows:- self-learning;- system self-adaptation;- autodiagnosis on K line;- reccognition of Fiat CODE (immobilizer) on CAN serial line + W line (redundant line);- cold starting check control;- control of combustion - Lambda sensors;- detonation control;- control of mixture enrichment during acceleration;- fuel cut-off during release of accelerator pedal;- fuel vapour recovery;- control of maximum rpm;- fuel pump control;- climate control system control;- cylinder position recognition;- control of optimum injection time for each cylinder;- adjustment of ignition advance;- idle speed management (also dependent on battery voltage - electrical balance management function);- management of throttle opening laws (accelerator pedal - torque request maps);- fan control with 3 drivers;- connection with ABS/ASR/VDC control unit;- cruise control (where fitted);- connection with the control panel;- torque management;EOBD OPERATION- fuel system diagnostics;- catalytic converter diagnostics;- misfire diagnosis; detection of failed combustion;- Lambda sensor diagnosis (pollution or signal distortion).Torque control strategyThe drive-by-wire control systems are vital in satisfying the legal requirements such as fuel consumption and emissions as well as for improving the driveability of vehicles with petrol engines (starting, heating, transition response, safe driving).The torque for petrol engines is mainly affected by the throttle valve which controls the mass of air introduced by the engine, (depending on the position of the accelerator pedal; more precisely, the request for power by the user, coming from the accelerator pedal, does not directly control the opening of the throttle valve, as in traditional systems with mechanical bowden cables, but is processed electronically by the control unit before being implemented by the throttle electric motor), and therefore also the filling of the cylinder.In addition to this there are other parameters that affect the variation of the engine torque: the ignition angle, the air/fuel (Lambda) radtio, the deactivation of injection for some cylinders.INJECTION SYSTEM
The essential conditions to be met by the air-fuel mixture for efficient operation of engines with controlled ignition systems are mainly as follows:- the metering (air/fuel ratio) must be kept as close as possible to stoichiometric levels to assure maximum catalytic converter conversion capacity (max. efficiency).- the homogeneity of the mixture, consisting of petrol distributed throughout the air as finely and uniformly as possible.Information that the control unit processes to control optimum metering is received by electrical signals emitted by:- air flow meter and (built in) air temperature sensor, for the exact quantity of air taken in;- rpm sensor that generates a sinusoidal signal whose frequency is an indicator of engine rpm.The control unit uses this signal to detect MISFIRE.- throttle potentiometer, to recognize the accelerator request conditions (the dual throttle potentiometer is, in reality, a safety feature of the DbW system and has the main function of monitoring the effective position of the throttle valve controlled by the activating motor, in particular during the management of possible fault conditions and the implementation of recovery strategies).The torque request information by the driver is recognized by the control unit by means of the accelerator pedal dual potentiometer.- coolant temperature sensor 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 catalytic converter.IGNITION SYSTEM
The ignition system is the static, inductive discharge type (i.e. without a HT distributor) with the power module located inside the DIS (external ignition module).The ignition system ensures that each coil supplies cylinders 1-4 and 2-3, respectively (lost spark system).The advantages of this solution are:- lower electrical overload;- guaranteed constant discharge at each spark plug.The control unit contains a memory map with a set of optimum ignition advance values (for the cylinder in combustion phase) that the engine can adopt according to the required speed and engine load.The control unit corrects the advance value mainly on the basis of:- engine coolant temperature- intake air temperature- detonation.- throttle valve position.Information that the control unit processes to control the coils is received by electrical signals emitted by:- air flow meter and air temperature sensor, for the exact quantity of air taken in;- rpm sensor that generates an alternating single-phase signal whose frequency is an indicator of engine rpm;detonation sensor (on the rear part of the crankcase between cylinders 2 and 3) to recognise the cylinder with knock and thus correct the ignition advance;- throttle position potentiometer to recognise minimum, partial and full load conditions.DIAGRAM SHOWING INFORMATION ENTERING/LEAVING 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 replacing the integrated throttle casing;- removal-refitting or replacement of the rpm sensor/phonic wheel for detection of misfiring. | The Motorola ECU carries out a special phonic wheel learning procedure; this procedure does not take place automatically, but should be carried out by a suitable command on the K line using diagnostic equipment.The values stored by the control unit are maintained when the battery is disconnected. |
System self-adjustment
The control unit 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).The control unit modifies the basic map in relation to engine specifications when new on the basis of an exhaust gas analysis.The self-adjustment parameters are not deleted if the battery is disconnected.Self-diagnosis
The control unit auto-diagnostic system 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 indicates engine management faults and also faults detected by EOBD diagnostic strategies.The MIL warning light operating (MIL) strategy is as follows:- with the ignition on, the warning light comes on and remains on until the engine has been started up. The control unit self-diagnostic system checks the signals coming from the sensors comparing them with the permitted limits.Fault indication during start up:- 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.Fault indication during operation:- the warning light comes on in flashing mode to indicate possible catalytic converter damage due to misfiring.- the warning light comes on in constant mode to indicate the presence of engine management or EOBD diagnostic errors. | Not all faults lead to the MIL EOBD warning light coming on. The effective presence of faults should be checked by reding the control unit errors memory with the diagnostic socket on the K line. |
Fiat code recognition
The moment the control unit receives the ignition ON signal it converses with the Fiat CODE control unit (via the body computer on the CAN serial line; if there are failure conditions on the line, the dialogue takes place on the W line) to obtain the go ahead for starting.Cold starting control
The following occurs in cold starting conditions:- a natural weakening of the mixture as a result of poor evaporation of the fuel at low temperatures;- fuel condensation on inner walls of the intake manifold;- increased lubrication oil viscosity.The electronic control unit detects this condition and corrects the injection time on the basis of:- coolant temperature;- intake air temperature;- battery voltage;- engine rpm.The ignition advance is determined solely on the basis of rpm and coolant temperature.Whilst the engine is warming up, the control unit 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.Control of combustion - lambda sensors
In EOBD systems, the Lambda sensors are all the same type and located upstream of the catalytic conversion system and downstream of the converter. The upstream sensors monitor concentration and are known as the 1st loop (closed loop of upstream sensor). The sensor downsream of the catalytic converter is used for the fault diagnosis of the catalytic converter (in the Motoroal system the downstream sensor is only used to carry out the catalytic converter fault diagnosis).Control of detonation
The control unit detects the presence of detonation (engine knock) by processing the signal coming from the relevant sensor.The control unit continuously compares the signals coming from the sensor with a threshold which is, in turn, continually updated to take into account background noise and engine ageing.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 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.Control of enrichment during acceleration
If, during the acceleration request, the variation in the air flow meter signal exceeds a pre-set level, the control unit increases the injection (time) to compensate for the variation in the mixture ratio due to the increased pressure in the intake manifold (less fuel evaporation): this allows the required engine speed to be reached quicker.RecoveryThe control unit replaces the signal coming from the air flow meter which is faulty with the throttle potentiometer signal.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 1300 - 1500 rpmIf there is no supply, the number of revs decreases with the speed depending on 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 value, the fuel supply is partly restored so that there is a "gentle accompaniment" towards the idle speed.The levels for res| ... DATA ERROR - CROPPED TEXT | Ошибка данных - Текст обрезан ... |
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