244001924 - E5031 DESCRIPTION OF LPG FUEL SYSTEM ELECTRONIC MANAGEMENT

Description

The petrol supply system is managed by a control unit that controls both ignition and injection.The LPG supply system is managed by another control unit that controls LPG injection and the LPG/petrol switching logic; injection takes place either automatically or manually using the special switching button in the dashboard.The two control units are connected to one another by means of a special high speed CAN line which allows optimum engine management in all operating conditions and with any type of fuel supply system.Depending on the signals received from the numerous sensors, the two control units, which share some signals from certain sensors, operate the respective actuators that are connected, managing the following systems:petrol supply;LPG supplyair supply;engine cooling;fuel vapour recirculation;combustion - Lambda sensor control;control of exhaust with catalytic silencer.The current version of the system also includes the EOBD function (European On Board Diagnosis) - conforming to Directive 98/69/CE (EURO 3) - that allows the continuous fault diagnosis of the components for petrol operation correlated with emissions and signals the deterioration of any of these components by switching on the warning light.The diagnostic system includes:the catalytic silencer which, in the case of a malfunction, does not convert the pollutants produced by the engine;the Lambda sensors;misfire, where the unburnt fuel reaches the catalyzer where the thermal conversion reactions produce a sudden increase in temperature damaging the actual catalyzer.The LPG system complements the basic system and the operation of the basic system is not affected in all operating conditions.The specific control unit manages the phased, sequential LPG injection and the activation of the LPG cut out solenoid valves as well as the LPG pump; in addition it controls the deactivation of the petrol pump.Injection takes place directly through the operation of the specific LPG system injectors.The ignition advance is achieved 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. All the other engine management functions, including the ignition advance, are left to the basic engine management control unit.The engine normally runs on LPG.If the LPG has run out (pressure below a certain value), the LPG control unit automatically switches to petrol operation and the special warning light comes on.Once the LPG has been refilled, the system automatically switches back to LPG operation.

For starting and after refilling with LPG the engine normally runs on petrol for a few seconds to keep the pump, the injectors and the specific ducts working properly.

The special switching button in the dashboard means that it is possible to switch to petrol operation manually: in this case both the green LED on the actual button and the special warning light in the instrument light up.If the button is pressed again the system reverts to LPG operation.