2889390 - E5030 PETROL ENGINE ELECTRONIC MANAGEMENT - Description (BIPOWER)

Description

The petrol fuel system is managed by a control unit, which controls both the ignition and the fuel injection.The methane fuel system is managed by another control unit which controls the methane injection and the logic for the methane/petrol supply changeover, which takes place automatically or manually via the specific changeover button located on the dashboard.The two control units are connected to each other by a specific high-speed CAN line, which permits optimum engine management under all operating conditions and with any type of fuel supply.

On the basis of the signals received from several sensors, the two control units, which share signals from some sensors, control the respective connected actuators, managing the following system:

• petrol supply
• methane supply;
• air supply system;
• engine cooling;
• fuel vapour recirculation.:
• control of combustion - Lambda sensors
• control of exhaust with catalytic silencer.

This version of the system also includes the EOBD (European On Board Diagnosis) system - conforming to Directive 98/69/CE (EURO 3) - permits continuous diagnosis of the components - relating to petrol operation - associated with emissions, and by the warning light coming on, indicates any deterioration of these components.

Among other things, the system diagnoses:

• the catalytic converter, which in the case of a malfunction does not convert the pollutants produced by the engine;
• the Lambda sensors (oxygen sensors);
• the lack of combustion, so unburnt fuel reaches the catalyzer where the thermal conversion reactions cause a sudden increase in temperature, damaging the catalyzer.

The methane system is additional to the basic system, and does not alter the operation of the basic system under any operating conditions.The specific control unit manages the methane injection, of the phased sequential type, and the activation of the gas (methane) cut-off solenoids, and also fuel pump deactivation.The injection is implemented directly by controlling the specific methane system injectors. The ignition advance is regulated by sending to the 'basic' engine management control unit the change in advance to be added to that applied during operation on petrol. This communication takes place via the CAN line present between the two control units.A specific methane pressure and temperature sensor on the manifold; it corrects the injection times, thus controlling the exhaust emission values, which come within EURO3 regulations-. EOBD. also in methane operation.All the other engine control functions, including ignition advance, are left to the 'basic' engine management control unit.

The engine normally runs on methane.

if the methane runs out, the system automatically switches over to running on petrol and the appropriate warning light comes on. Once the methane has been refilled, the system automatically switches back to running on methane.

During starting and after refilling with methane the engine continues to run on petrol for several seconds to ensure that the pump, the injectors and the specific ducts are working properly.

The special switching button in the dashboard makes it possible to switch manually to running on petrol: in such a case both the green LED on the button and the special warning light in the instrument panel come on.By pressing the button again, methane operation is restored.

The manual switching from petrol to methane and viceversa should not be done whilst starting the engine. This also occurs only if the engine rpm is lower than 2000 rpm.

For more details, especially on methane operation, see  Characteristic of working principle 1058  CNG FUEL SYSTEM . The system is also controlled by means of four relays located in the fuse and relay box in the engine compartment near the actual control unit. The supply lines for the two control units and the various system components (sensors and actuators) are protected by a special maxifuse and three other fuses also located in the above mentioned box.