CONSTRUCTION SPECIFICATIONS

The system for running on two types of fuel comprises the Magneti Marelli IAW 48P2 system for petrol operation and the Metatron METAFUEL 5D0 system for operating on LPG. The two systems are connected via a high speed CAN line.The Magneti Marelli IAW 48P2 system belongs the category of systems integrated with:inductive discharge, digital, electronic ignitionstatic advancesequential, phased type electronic injection (1-3-4-2).The Metatron METAFUEL 5D0 belongs the category of systems integrated with:sequential, phased type electronic injection (1-3-4-2).All components of the LPG are transparent to the basic system and the operation of the basic system is not affected under any operating conditions.The two control units share some of the system elements. This sharing is transparent to the basic system.The list of components shared by the two systems, connected in parallel, is as follows:intake manifold pressure sensor;throttle position sensor;engine rpm sensor;engine timing sensor;Lambda sensor upstream of the catalytic converter.The list of additional components for the LPG system is as follows:electronic injection unit for LPG METAFUEL 5D0LPG pressure sensor in the injector rail;LPG cut out solenoid valves relay on the tank andon the supply line;LPG cut out solenoid valve on the tank;LPG cut out solenoid valve relay on the return line;LPG cut out solenoid valve on the return line;LPG cut out solenoid valve on the supply line;LPG / petrol switch;LPG injector relay;LPG injectors;petrol pump cut out relay;LPG level sensor;LPG pump current sensor;LPG pump.

FUNCTION

There are two system operating modes: on petrol and on LPG. The two control units are always supplied whilst the engine is running.Switching from one to another takes place in the following ways:manually, using the (SEDIMO) selector located in the dashboard;automatically, decided upon by the METAFUEL 5D0 electronic unit for LPG or in particular recovery conditions where running on LPG is not advisable.The operating mode is signalled by means of the PETROL operation warning light (POWER MODE) in the sedimo component. Irrespective of the position of the switch, this indicator shows the operating mode using the two LEDs incorporated in the selector: green LED (LPG operation), orange LED (petrol operation).There is a high speed CAN communication line between the two electronic units through which data, commands and other information required for the correct management of the two control units is exchanged.

Diagram showing information entering/leaving the control unit

The communcation between the petrol engine management control unit and the LPG engine management control unit takes place via the CAN line.

OPERATING LOGICS

Petrol operation

In this operating mode there are no functional variations in relation to the basic system.The Magneti Marelli 48P.2 basic electronic unit performs in the same way 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 selector positioned to LPG mode before starting). The petrol pump is deactivated during LPG operation, except during starting, for a period of a few seconds, corresponding to the activation of the LPG injection, necessary in order to be able to carry out the fault diagnosis of the deactivation relay.The METAFUEL 5D0 electronic unit manages the sequential, phased type injection of the LPG, the activation of the LPG cut out solenoid valves and the deactivation of the petrol pump. All the other engine management functions, including the ignition advance, are left to the basic unit. Injection takes place directly through the operation of the specific LPG system injectors. The ignition advance is adjusted by sending the basic electronic unit the advance variation to be added to the one for petrol operation. This communication takes place via the CAN line between the two control units. The commands for the petrol injectors, the fault diagnosis and the petrol self-learning strategy are also disabled via the CAN line. The other basic electronic unit functions are carried out normally and all the input signals remain unchanged. All the commands are implemented as usual (stepper, ignition, etc.).The METAFUEL 5D0 electronic unit processes the information coming from the basic system sensors, that coming via the CAN line from the 48P2 control unit and the information coming from the additional sensors for LPG operation in order to recognize the system operating conditions and produce suitable commands for the LPG injectors.The activation of the LPG cut out solenoid valves and the deactivation of the petrol pump takes place when switching from petrol to LPG. When switching from LPG to petrol, the METAFUEL 5D0 electronic unit operates in the opposite way to previously (i.e. it deactivates the LPG cut out solenoid valves and reactivates the petrol pump). In this case the petrol pump is switched on immediately to pressurize the system.The management strategies use typical curves and control parameters stored in the METAFUEL 5D0 electronic unit memory. The calibration figures are defined on the basis of performance, consumption, emission and driveability aims.The specific management strategies for the LPG system are basically as follows:Engine Signal ManagementIgnition managementInjection managementIdle speed managementSystem self-adjustmentStart-upOperation during acceleration and decelerationCut-off operationOperation in full load conditionsProtection beyond revsBarometric correctionFuel vapour recoveryControl of combustion gases - Pre-catalyzer Lambda sensorAir conditioning compressor connectionLPG level signalPetrol pump operation;LPG pump operation;LPG cut out solenoid valves and LPG pump operation;LPG injector operation;Switching between two operating modes (petrol and LPG)Connection with electronic key (Fiat CODE)System self-diagnosis

Engine Signal Management

The METAFUEL 5D0 electronic unit recognizes the engine timing and determines the injection timing angle. This recognition takes place by processing the signals coming from the timing sensor and from the rpm and TDC sensor. These two signals make up the engine signals. The synchronization of the signals and signal wave shapes are the same as those for the basic electronic unit.

Ignition management

The coil charging time and the moment of ignition in relation to TDC are always determined and managed by the basic electronic unit which receives the variation in the advance to be implemented from the METAFUL 5D0 via the CAN.The METAFUEL 5D0 electronic unit memory contains a map of the advance shift values according to the engine speed and load conditions. The calculation of the advance correction involves selecting a basic value and correcting in according to the coolant temperature.

Injection management

The aim of the fuel management is to supply the correct amount of fuel required by each cylinder to satisfy the objectives of performance, consumption and engine emissions. The METAFUEL 5D0 unit does not manage the starting stage.The injection is the sequential, phased type.The METAFUEL 5D0 control unit uses an indirect type engine load measurement system (speed-density). This method is used to calculate the quantity of fuel to inject into each cylinder for each engine cycle.The LPG is supplied by modulating the injector opening time. The injector inlet pressure is regulated by the LPG pump.The METAFUEL 5D0 unit injection strategies make it possible to supply the correct amount of LPG to the engine in all operating conditions (acceleration, deceleration, altitude, cold weather).

Idle speed management

The idle speed management (stepper management) is carried out by the basic electronic unit; the METAFUEL 5D0 unit modifies the idle speed by means of a suitable offset transmitted via the CAN.

System self-adjustment

The self-adjustment strategies allow the adjustment of the injection to the changes in the system due to production dispersions and ageing of the engine.

Start-up

The engine is always started up on petrol.

Operation during acceleration and deceleration

These operating conditions are identified by means of the throttle position and manifold pressure signals.During these two stages the METAFUEL 5D0 unit adjusts the fuel injection as quickly as possible in order to maximize acceleration torque and ensure optimum driveability during deceleration.

Cut-off operation

The fuel cut off strategy is implemented when the throttle is closed at high engine speeds. This strategy is only enabled above a certain coolant temperature level. The METAFUEL 5D0 electronic unit manages the inlet and outlet from this stage in order to reduce emissions during these engine operating conditions.

Operation in full load conditions

Full load operation is managed by the METAFUEL 5D0 electronic unit with air/LPG mixture enrichment strategies that are similar to those for petrol engine management systems.

Protection beyond revs

The METAFUEL 5D0 electronic unit manages the protection of the engine outside of revs. This protection involves cutting off the injection when a given speed is exceeded. Normal injection is resumed when the speed returns to below the critical value.

Barometric correction

There is a strategy in the METAFUEL 5D0 control unit that recognizes the altitude and implements a barometric correction of the mixture strength.

Fuel vapour recovery

When running on LPG the management of the petrol canister purge is carried out by the METAFUEL 5D0 unit by sending the command to the basic unit via the CAN line.As far as the LPG fuel supply system is concerned, it is sealed. The LPG pressure inside the system never, under any circumstances, exceeds the maximum pressure. LPG vapour recovery systems are therefore needed.

Control of combustion gases - pre-catalyzer Lambda sensor

The METAFUEL 5D0 electronic unit uses the signal for the Lambda sensor upstream of the catalyzer to control the metering of the air/LPG mixture in order to ensure maximum catalyzer conversion efficiency.The METAFUEL 5D0 electronic unit manages the heaters for the two Lambda sensors, via the CAN, located upstream and downstream of the catalyzer.

Air conditioning compressor connection

The METAFUEL 5D0 electronic unit is not connected to the air conditioning system.The switching on and off of the compressor in certain operating conditions to improve the performance of the engine is managed by the basic electronic unit through the same modes and operating conditions as for the basic system.

LPG level signal

The METAFUEL 5D0 electronic unit determines the refilling of the LPG tank on the basis of the information it receives from the level sensor inside. This information is then sent from the METAFUEL 5D0 control unit to the special gauge with the built in LED in the SEDIMO device in the instrument panel.

Petrol pump operation

The petrol pump is closed to earth by the inertia switch and is operated by the METAFUEL 5D0 electronic unit via a special relay.The petrol pump is stopped:if there is a LPG/petrol switch;if the inertia switch has gone off.When switching from LPG to petrol the METAFUEL 5D0 electronic unit immediately reactivates the petrol pump to pressurize the system.

LPG pump operation

The LPG pump is operated by the METAFUEL 5D0 electronic unit. The current sensor detects the current absorption by the LPG pump determining whether or not the pump is working properly; on the basis of the information received from the current sensor, the METAFUEL 5D0 control unit either does or does not switch to petrol operation.

LPG cut out solenoid valve and LPG pump operation

There are 3 LPG cut out solenoid valves:1 solenoid valve fitted on the canister;1 solenoid valve fitted on the supply line;1 solenoid valve fitted on the return line;The 2 LPG collection solenoid valves (on the tank and on the supply line) are connected to one another in parallel, closed to earth by the inertia switch and operated by the METAFUEL 5D0 electronic unit by means of a special relay. A second relay supplies the solenoid valve fitted on the return line.The solenoid valves are closed and the pump is switched off:if the engine speed goes below a certain level;after a certain time with the key ON without the engine being started up (timed enablement);if there is an LPG/petrol switch;if the inertia switch has gone off;if the current sensor detects irregular current absorption by the LPG pump.After the switch from LPG to petrol, the METAFUEL 5D0 electronic unit deactivates the LPG cut out solenoid valves.

LPG injector operation

The operation of the LPG injectors is the phased sequential type.The injector timing varies according to the engine speed and the intake air pressure in order to improve the cylinder filling with benefits in terms of consumption, driveability and pollution.The injectors receive an electrical supply via a specific relay: the LPG engine management control unit closes the contacts for the appropriate part of the LPG injectors according to the situation.

Switching between two operating modes (petrol and LPG)

The function is regulated by the METAFUEL 5D0 electronic unit which also manages the signalling of the operating mode incorporated in the (SEDIMO) indicator by means of two LEDs at the side of the LPG/Petrol selector (1).The (SEDIMO) indicator includes the following functions:LPG/Petrol selector (1);LPG level indicator (4) consisting of 5 LEDs, 4 of which are green and 1 yellow to indicate the reserve; the yellow LED comes on when only the first green LED remains on and it stays on even when the first green LED goes out. In all other cases (except whilst the vehicle is being started) the yellow reserve LED is off;"Operating mode" indicator consisting of two LEDs at the side of the selector button: a green LED (2) used for the LPG operating mode and a yellow/amber LED (3) for petrol operation.Position "G" of the selector (1) indicates the choice to run on LPG (green LED on) (2), whilst running on petrol is indicated by the amber yellow LED lit up (3).The user can switch between the two operating modes at any time.

The lighting up logic for the "petrol mode" indicator in the SEDIMO component is, irrespective of the selector switch position, to signal:a) LPG operation = green LED onb) petrol operation = amber yellow LED onThe LPG/Petrol switching strategy differs from the Methane/Petrol one in that given the nature of the fuel a fuel level sensor that allows an initial analysis of the LPG present in the tank is required. This sensor is also used for the management of the level reading (LED indicator incorporated in the SEDIMO device).The pressure of the LPG in the canisters is utilized in identifying the "empty canisters" condition for the automatic return to petrol operation. when the LPG is running out, the current absorbed goes down from around 6A to about 2.5A.The current absorbed by the LPG pump is measured by a current sensor located between the pump activation relay and the actual LPG pump.Switching from petrol to LPGThe following cases are possible:1. Manually, by the user with the engine switched offSelector switch position during starting: "GAS mode""Operating mode" LED comes on during starting: amber yellow LED for "Petrol mode".Whilst the engine is being started the amber yellow LED for the "PETROL mode" is on (activated), whilst the green LED for the "LPG mode" is off, indicating that the engine is running on petrol. When the engine has been started (as soon as it out of the cranking stage) the following situation occurs:automatic switching to LPG;The "LPG mode" green LED comes on and the amber yellow "Petrol mode" LED goes out.The switching to LPG is inhibited if the current absorbed by the LPG pump is not above a pre-set level of 4.5A corresponding to the "tank not empty" condition, if the temperature of the engine coolant is too low or if a fault has been diagnosed in the system.2. Manually, by the user with the engine running.Selector switch initial position: "Petrol mode""Operating mode" LED comes on during starting: amber yellow LED for "Petrol mode".By selecting the methane mode the user starts the petrol to LPG switching function which only takes place when the following conditions are satisfied:LPG pressure in the tank within a certain range;engine coolant temperature above a certain level;LPG pump current above a level corresponding to "tank not empty";no faults detected during the fault diagnosis of the METAFUEL 5D0 electronic unit.If this is the first switching to LPG at the key on, the "petrol mode" warning light goes out with a delay of a few seconds to allow the fault diagnosis of the petrol pump deactivation relay.Switching from LPG to petrolThe following cases are possible:1. Automatically (with the engine running).Selector switch initial position: "LPG mode""Operating mode" LED comes on during: green "LPG mode" LEDThe automatic switching from LPG to petrol takes place according to decisions by the METAFUEL 5D0 unit control strategies and only if the following operating conditions are satisfied:LPG pressure in the tank outside of a certain range;LPG pump current below a certain level (end of LPG recognition);transducer signal below a certain level;identification of a fault in the system.If one of the above conditions is satisfied, there is an immediate switch from LPG to Petrol and the "Petrol mode" amber yellow LED comes on and, at the same time, the "LPG mode" green LED goes out. The position of the selector remains unchanged.After the switching has taken place, LPG operation is completely inhibited until the cause of the automatic switching is eliminated (fuel supply or elimination of the fault).2.Manually, by the user with the engine running.Selector switch initial position: "LPG mode""Operating mode" LED comes on during: green "LPG mode" LEDBy pressing the selector switch the user starts off the LPG to Petrol switching function that takes place immediately together with the amber yellow LED for the "Petrol mode" coming on and the "LPG mode" green LED in the SEDIMO going out.

Connection with electronic key

The METAFUEL 5D0 control unit is not connected to the electronic key congtrol unit (Fiat CODE).The electronic key system only maintains its operation with the basic system; therefore, in order to be able to switch to LPG, it is necessary to receive the go ahead from the petrol control unit and this go ahead is given if the check with the Fiat CODE is okay and the operation with the electronic key is guaranteed in all conditions.Starting with a key that has not been memorized in the electronic key control unit is not permitted in either operating mode (petrol or LPG). The procedure for personalizing the vehicle or programming the keys is the same and should be carried out in the petrol mode.

System self-diagnosis

The METAFUEL 5D0 electronic unit carries out the fault diagnosis of the input/output, cyclically checking the signals and an internal self-diagnosis programmes the codes in the EEPROM in the case of malfunctions (passive self-diagnosis).It is also possible to activate the individual actuators, using the diagnostic equipment, checking their efficiency (active self-diagnosis).The total cancellation of the EEPROM is carried out by means of the diagnostic equipment.If there is a fault, the control unit manages the alternative functions to keep the engine running where possible to allow the vehicle to reach a service centre or, in more serious cases, it automatically switches the system to petrol operation, switching off the LPG level gauge in the SEDIMO device in the dashboard (recovery).

PASSIVE SELF-DIAGNOSIS

The METAFUEL 5D0 electronic unit carries out the fault diagnosis of the input/output, cyclically checking the signals and in the case of malfunctions, programming the codes in the EEPROM (passive self-diagnosis). The fault diagnosis carried out and the recovery actions in the case of a fault in the following components are reported:

Manifold pressure sensor

The METAFUEL 5D0 electronic unit carries out the following electrical fault diagnosis from the signal coming from the manifold pressure sensor:short circuit to earth or open circuit;short circuit to Vbattery.If a fault is detected, the control unit implements the following recovery actions:return to petrol operating mode and switching on "petrol mode" amber yellow LED in the mode selector (SEDIMO);warning light in instrument panel lit up.

Throttle position sensor

The METAFUEL 5D0 electronic unit carries out the following electrical fault diagnosis from the signal coming from the LPG pressure sensor:Short circuit to earth;Short circuit to Vbattery or open circuit.If a fault is detected, the control unit implements the following recovery actions:return to petrol operating mode and switching on "petrol mode" amber yellow LED in the mode selector (SEDIMO);warning light in instrument panel lit up;

LPG pressure sensor

The METAFUEL 5D0 electronic unit carries out the following electrical fault diagnosis from the signal coming from the LPG pressure sensor:Short circuit to earth;Short circuit to Vbattery or open circuit.If a fault is detected, the control unit implements the following recovery actions:Return to petrol operating mode and switching on "petrol mode" amber yellow LED in the mode selector (SEDIMO);Warning light in instrument panel lit up;The LPG level guage in the SEDIMO is off.

LPG level sensor

The METAFUEL 5D0 electronic unit carries out the following electrical fault diagnosis from the signal coming from the LPG level sensor every 130 ms:short circuit to earth;short circuit to Vbattery or open circuit.If a fault is detected, the control unit implements the following recovery actions:the LPG level gauge in the instrument panel is off (LPG operation is however allowed).

LPG pump current sensor

The METAFUEL 5D0 electronic unit cyclically carries out an electrical fault diganosis on the current sensor every 130 ms, signalling the following problems:LPG pump absorption below 5A: the pump does not collect LPGLPG pump absorption above 10A: pump overloaded.If a fault is detected, the control unit implements the following recovery actions:Automatic return to petrol operating mode and switching on "petrol mode" amber yellow LED in the mode selector (SEDIMO).

CAN line

The METAFUEL 5D0 electronic unit cyclically carries out a functional diagnosis on the CAN line to check for a break in the connection.If a fault is detected, the control unit implements the following recovery actions:temporary return to petrol operating mode and switching on "petrol mode" amber yellow LED in the mode selector (SEDIMO). Return to LPG operating mode on restoration of connection with the amber yellow LED for the "Petrol mode" in the mode selector (SEDIMO) going out;Return to LPG operating mode on restoration of connection with the amber yellow LED for the "Petrol mode" in the mode selector (SEDIMO) going out;definitive return to petrol operating mode and then switching on of amber yellow LED for "Petol mode" in the mode selector (SEDIMO) after 5 interruptions in a single trip and lighting up of the warning light in the instrument panel.

Pre-catalyzer Lambda sensor

The METAFUEL 5D0 electronic unit cyclically carries out a functional fault diagnosis signalling that the Lambda sensor is not working properly in the case of a fault or malfunction.If a fault is detected, the control unit implements the following recovery actions:disabling closed-loop mixture strength check;inhibition of self-adjustment strategies.

Rpm sensor

The METAFUEL 5D0 electronic unit checks the accuracy of the counting of the impulses coming from the rpm sensor facing the flywheel with 58 teeth, signalling if there is a fault or malfunction:signal not present.If a fault is detected, the control unit implements the following recovery actions:resynchronization;the vehicle does not move or cuts out.

Timing sensor

The METAFUEL 5D0 electronic unit cyclically carries out a fault diagnosis on the timing sensor signalling the following in the case of a fault or malfunction:signal not plausible.There are no recovery actions planned, the system will operate at 360 degrees with the correct or incorrect timing.

LPG injectors

The METAFUEL 5D0 electronic unit cyclically carries out an electrical fault diganosis on the LPG injectors signalling the following problems:injector cold side open circuit;injector cold side short circuit to earth;injector cold side short circuit to Vbattery.If a fault is detected, the control unit implements the following recovery actions:return to petrol operating mode;warning light in instrument panel lit up.

LPG injector relay

The METAFUEL 5D0 electronic unit cyclically carries out an electrical fault diganosis on the LPG injector relay coil every 130 ms, signalling the following problems:short circuit to earth or open circuit: this fault diagnosis is only possible in the petrol operating mode;short circuit to Vbattery: this fault diagnosis is only possible in the LPG operating mode.If a fault is detected, the control unit implements the following recovery actions:Return to petrol operating mode and switching on "petrol mode" amber yellow LED in the mode selector (SEDIMO);

LPG cut out solenoid valve relay (on supply) and LPG pump and LPG cut out solenoid valve relay (on return)

Every 130 ms the METAFUAL 5D0 electronic unit carries out an electrical fault diagnosis on the LPG cut out solenoid valve relay (on the supply) and the LPG pump and on the LPG cut out solenoid valve relay (on the return) signalling the following faults:short circuit to earth or open circuit: this fault diagnosis is only possible in the petrol operating mode;short circuit to Vbattery: this fault diagnosis is only possible in the LPG operating mode.If a fault is detected, the control unit implements the following recovery actions:Return to petrol operating mode and switching on "petrol mode" amber yellow LED in the mode selector (SEDIMO);

Petrol pump cut out relay

The METAFUEL 5D0 electronic unit cyclically carries out an electrical fault diganosis on the petrol pump cut out solenoid valve relay coil every 130 ms, signalling the following problems:short circuit to earth or open circuit: this fault diagnosis is carried out, in LPG operating mode, once only during starting on petrol and then switching to LPG;short circuit to Vbattery: this fault diagnosis is possible in both LPG and petrol operating modes.There are no recovery actions.

METAFUEL 5D0 INJECTION CONTROL UNIT

The control unit is fitted under the passenger seat and is capable of withstanding high temperatures.It is a digital type unit with a microprocessor featuring a high calculation capacity and is accurate, reliable, versatile, with low energy consumption and is maintenance-free.The task of the electronic control unit is to process the signals coming from the additional sensors belonging to the LPG system, the signals for the sensors shared with the petrol system and the information coming from the Magneti Marelli 48P2 control unit through the application of software algorithms and to control the operation of the actuators (in particular the LPG injectors and LPG cut out solenoid valves) in order to ensure the optimum operation of the engine.

Metafuel 5D0 control unit pin out

The diagram below shows the control unit pin out.

LPG INJECTORS

Construction specifications

The special LPG injectors are the side feed type.Thanks to the low electrical resistance (1.8 Ohm) offered by the coil, this type of injector makes it possible to prevent vapour lock following the heating of the LPG which, by its very nature, already has a lower vapourization level than petrol.The injectors (1) are fitted on specific injector holder bodies (2) and are connected to the individual intake manifolds by means of special LPG feed connectors (3) (rubber pipes). There is a threaded opening in every intake manifold in which these connectors for transferring liquid LPG from the injectors is screwed into.The injectors are supplied like petrol injectors and operate at a pressure that varies between 3 and 21 bar and they are activated by electrical commands from the Metatron 5D0 electronic control unit.

Operation

The injector operating logic is the "phased, sequential" type, in other words the four injectors are operated individually depending on the engine cylinder inlet sequence, whilst the supply for each cylinder can already begin during the expansion stroke until the inlet stroke has already started.

LPG PRESSURE SENSOR

The pressure sensor (1) is fitted on the supply line (2).It receives a 5V supply from the LPG control unitThe LPG pressure (which varies in the injector holder body) is measured by the pressure sensor which has the task of providing the control unit with one of the basic parameters for calculating the correct LPG injection time.