Acceleration

The fuel cut-off strategy is activated when the ECU recognises that the throttle is in closed position (throttle potentiometer signal) and engine speed exceeds 2000 rpm. The ECU activates cut-off only when engine temperature exceeds 0° C.

The fuel supply is restored when the throttle is no longer closed.

1. A. entering cut-off
2. B. leaving cut-off

Acceleration

During this stage, the ECU increases the amount of fuel required by the engine (to achieve maximum torque) on the basis of signals from the following sensors:

• - throttle potentiometer;
• - absolute pressure sensor;
• - rpm and TDC sensor.

The base pulse constant is multiplied by a factor according to coolant temperature and accelerator throttle opening speed.

If an abrupt change in injection time is calculated when the injector is already closed, the ECU reopens the injector (extra pulse), in order to make the concentration up to the required level as quickly as possible. Subsequent injections are automatically increased as described previously.

1. A. normal injection time
2. B. injector re-opening (extra pulse)
3. C. injection time including enrichment
4. OFF. engine under steady-state conditions
5. ON. engine under transient conditions