Fuel vapour recovery

Fuel vapour recovery

Fuel vapours (pollutants) are collected in an active carbon canister and are conveyed to the intake ducts to be burnt.

This is ensured by means of a solenoid valve controlled by the ECU.

The valve is closed for 60 seconds after start-up and opened for 90 seconds.

During this time (90 seconds) the lambda sensors meter carburation and the values are compared against the basic ECU maps.

If there are no variations, the ECU closes the solenoid valve, otherwise it is kept open for other 90 seconds to allow canister wash-out.

The canister wash-out is nominally limited to a small percentage of intake air detected by the flow meter to ensure balance and disrupt driveability as little as possible.

Fuel pump control

The ECU:

• powers the fuel pump in the following conditions:
  • key at MAR (for 5 sec.)
  • key at AVV and rpm > 25.
• cuts off fuel pump power in the following conditions:
  • key at STOP
  • rpm < 25.

Engine rpm limitation

According to the engine rpm, the ECU:

• stops feed to the injectors over 6800 rpm (a maximum of 7000 rpm is allowed for less than 5 sec.).
• start piloting the injectors again under 6600 rpm.

The canister wash-out is nominally limited to a small percentage of intake air detected by the flow meter to ensure balance and disrupt driveability as little as possible.