2892434 - Introduction - LPG FUEL SYSTEM. (GPOWER)
CONSTRUCTION FEATURES
The dual fuel system consists of a Magneti Marelli IAW 4EF.G1 basic system for petrol operation and an integral system (Metatron METAFUEL 5D0) for LPG operation. Both systems are connected via a high-speed CAN line.The Marelli IAW 4EF.G1 system belongs to the integrated system category with:
- inductive discharge digital electronic ignition
- static distribution
- sequential, phased electronic injection (1-3-4-2).
The Vialle/ Metatron METAFUEL 5D0.2B0 system belongs to the integrated system category with:
- sequential, phased electronic injection (1-3-4-2).
The list of components shared between the two systems via parallel connections is as follows:
- pressure sensor in the inlet manifold.
- throttle position sensor;
- engine rpm sensor;
- engine timing sensor
- Lambda sensor upstream of converter
The list of additional components for the LPG system is as follows:
- METAFUEL 5D0 LPG injection electronic unit
- LPG pressure sensor in the injector rail;
- relay for LPG cut-out solenoid on tank
- LPG cut-out solenoid on tank
- LPG cut-out relay on pressure regulator
- LPG/petrol selector;
- LPG injector relay;
- LPG injectors
- petrol pump cut-out relay;
- LPG level sensor
- LPG pump
OPERATION
The system can operate in two modes: petrol and LPG Both control units are permanently activated during engine operation.Switching between them can take place as follows
- manually via a selector on the dashboard
- automatically, determined by the METAFUEL 5D0 unit when the LPG has run out or under specific recovery conditions
 | For reasons connected with PETROL pump supply cut-off relay diagnosis, the PETROL warning light goes off after a certain time lag if the car is started in PETROLmode and then switched to LPG. |
Diagram of input/output information from the control unit
The petrol engine control unit and the LPG engine control unit communicate via CAN line
OPERATING STRATEGIES
Petrol operation
During this operating mode, the system works in the same way as the basic system The basic Magneti Marelli 4EF.G1 electronic unit does not change its behaviour and the system management strategies are as for the basic version.The specific parts of the LPG system do not interfere with the basic system in any way.Lpg operation
The engine works on methane from start-up (naturally with the selector set to LPG mode before starting). The petrol pump is consequently deactivated during LPG operation, except during start-up when it is active for a few seconds during LPG injection activation in order to diagnose the deactivation relay. The METAFUEL 5D0 manages phased sequential LPG injection, activation of the LPG cut-off solenoids and fuel pump deactivation. All other engine control functions, including the ignition advance, are managed by the base unit. The injection is activated directly by controlling special LPG system injectors. The ignition advance is adjusted by sending the basic electronic unit the advance change to be added to that applied during petrol operation. This communication takes place via the CAN line between the two control units. Other basic electronic unit functions are managed normally and all input signals remain unaltered. All commands are implemented as normal (stepper, ignition etc.).The METAFUEL electronic unit processes information from the basic system sensor, information received via the CAN line from the 4EF.G1 control unit and information from additional LPG operation sensors to recognise system operating conditions and generate LPG injector commands The LPG cut-off solenoids are activated and the petrol pump is deactivated upon switching from Petrol to LPG. When the system is switched from LPG -Petrol, the METAFUEL 5D0 works in the opposite way (i.e. the LPG cut-off solenoid is deactivated and the fuel pump is reactivated). In this case, the pump is turned on immediately to pressurise the system. Management strategies use typical curves and parameters stored in the METAFUEL 5D0 electronic unit. Calibration values are defined on the basis of performance, fuel consumption, emission and handling objectives.Management strategies specific to the LPG system are essentially as follows:
- Engine signal framework management
- Ignition management
- Injection management
- Idle speed management
- System self-adaptation
- Start-up
- Acceleration and deceleration
- Operation during cut-off
- Operation under full load conditions;
- Protection against excess rpm
- Barometric correction
- Fuel vapour recovery
- Control of combustion gas - Preconverter lambda sensor
- Air conditioning compressor connection
- LPG level indication
- Fuel pump control
- LPG pump control
- LPG cut-off solenoids and LPG pump control
- LPG injector control
- Switching betweenn both operating modes (Petrol and LPG)
- Connection to electronic key (Fiat CODE)
- System self-diagnosis
Engine signal framework management
The METAFUEL electronic control unit recognises the engine phase and determines the injection timing angle. Recognition takes place by processing signals from the timing sensor and the rpm and TDC sensor. These two signals make up the engine signal framework
Ignition management
The coil charge time and the ignition time in relation to TDC are always determined and managed by the basic electronic control unit, which receives the advance change to be applied from the METAFUEL 5D0 unit via CAN. The METAFUEL 5D0 unit contains an advance change value map based on engine speed and load. The advance correction calculation chain involves selection of a baseline value and its correction according to coolant temperature.
The advance correction calculation chain involves selection of a baseline value and its correction according to coolant temperature.
The aim of fuel management is to deliver the amount of fuel required to meet performance and engine fuel consumption and emissions targets. The METAFUEL 5D0 unit does not manage the start-up stage.Injection is phased, sequential. The METAFUEL 5D0 control unit uses an indirect engine load measurement system (speed-density) This method is used to calculate the amount of fuel to be injected into each cylinder for each engine cycle. LPG is delivered by modulating injector opening time. Injector input pressure is governed by the pressure reduction unit. The METAFUEL unit injection strategies allow the engine to be supplied with the correct amount of methane under all service conditions (acceleration, deceleration, altitude, cold).Idle speed management
Idle speed management (stepper management) is managed by the basic electronic unit. The METAFUEL 5D0 unit alters idle speed by means of an offset sent via the CAN network.
Self-adaptation of the system
Self-adaptive strategies allow the injection control to be adjusted to system shifts due to output dispersion and engine ageing.Start-up
The engine is always started using petrol.
Acceleration and deceleration
These operational conditions are indicated by means of throttle and manifold pressure signals.During these two stages, the METAFUEL 5D0 unit adjusts fuel injection as quickly as possible to maximise acceleration torque and optimise handling during deceleration.
Operating with cut-off
The fuel cut-off strategy is implemented upon recognition of throttle closed with engine speed high. This strategy is enabled only above a given coolant temperature value. The METAFUEL 5D0 electronic unit manages input and output from this stage to reduce emissions during this engine operating stage.
Operation in full load conditions
Full-load service conditions are managed by the METAFUEL 5D0 electronic unit by means air-LPG mixture enrichment strategies similar to those applied by petrol engine control systems.Protection against excess rpm
The METAFUEL 5D0 electronic unit protects the engine against excess rpm. This protection involves cancelling injection times when a given speed value is exceeded. Normal injection is reset when speed returns to below critical levels.
Barometric correction
The METAFUEL 5D0 control unit implements an altitude recognition and barometric correction strategy on the mixture concentration.
Fuel vapour recovery
During LPG operation, the fuel canister purge facility is carried out by the METAFUEL 5D0 unit by sending the command to the base unit via the CAN line.The LPG fuel system is sealed. LPG pressure in the system never exceeds maximum load pressure under any service conditions. LPG vapour recovery systems are not therefore required.
Control of combustion gas - lambda sensor
The METAFUEL electronic unit uses a signal from the lambda sensor upstream of the catalytic converter to control metering of the air-LPG mixture to obtain maximum conversion efficiency. The METAFUEL 5D0 electronic control unit manages heating of the two lambda sensors located upstream and downstream of the catalytic converter via the CAN line.
Air conditioning compressor connection
The METAFUEL 5D0 electronic control unit is not connected to the air conditioning system. Compressor activation and deactivation under certain operating conditions, to improve engine performance, are regulated by the basic electronic control unit using the same procedures and operating conditions as the basic system.Lpg level indication
The METAFUEL 5D0 receives a signal indicating the amount of liquid LPG in the tank from the LPG level device. this information is then sent by the METAFUEL 5D0 control unit to the indicator on the control panel.
Petrol pump control
The petrol pump is closed to earth by an inertia switch and governed by the METAFUEL 5D0 electronic unit via a special relay.The pump cuts out:
- if switching takes place between petrol/LPG
- if the inertia switch has operated.
Lpg pump control
The LPG pump is governed by the METAFUEL 5D0 electronic unit by means of a duty-cycle command that permits 5 speeds with different outputs. Speed 1 has been found to allow correct engine idle operation under all engine coolant conditions. For higher rpms, speed| ... DATA ERROR - CROPPED TEXT | Ошибка данных - Текст обрезан ... |
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