244001929 - E5032 METHANE FUEL SYSTEM ELECTRONIC MANAGEMENT DESCRIPTION

Description

The petrol supply system is managed by a control unit that also controls both ignition and injection.The methane supply system is managed by another control unit that controls methane injection and the switching logic for the methane/petrol fuel system which takes place 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
  • methane supply;
  • air supply;
  • engine cooling;
  • fuel vapour recirculation.
  • - control of combustion - Lambda sensors
  • - 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 (oxygen 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 methane 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 methane injection and the activation of the (methane) gas cut out solenoid valves in addition to the deactivation of the petrol pump.Injection takes place directly through the operation of the specific methane 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 methane.
If the methane has run out, the system automatically switches to petrol operation and the special warning light comes on. Once the methane has been refilled, the system automatically switches back to methane operation.
For starting and after refilling with methane 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 methane operation.
there should be no manual switching from petrol to methane operation and viceversa during starting. It also only takes place if the engine rotation speed is less than 2000 rpm.