Adaptive fuel direct injection system

A direct fuel injection system including a common rail (4) including a control unit (1), a pump (2) and a valve (3), controlled on an on or off basis by the control unit (1), in order to regulate the volume of fuel sent to the pump (2) to be fed into the common rail (4), said control unit (1) comprising

• first determination means (40) adapted to determine a first variable (a peak phase duration (27)) during which a command must be applied to the valve (3) in order to obtain a first objective variable (a peak current (38, 60)) greater than or equal to a reference value (a reference peak current (61)) necessary to cause a change of state of the valve (3),
• second determination means (70) adapted to determine a second variable (a holding ratio (28)) in accordance with which a command must be applied to the valve (3), after its change of state, in order to maintain a second objective variable (a holding current (39, 90)) greater than or equal to a reference value (a reference holding current (91)) necessary to maintain said state of the valve (3),
• application means adapted to apply said command to said valve (3) first continuously during said peak phase duration (27) and then by pulse width modulation in accordance with said holding ratio (28),
• adaptation means (42, 72) for the first variable (27) and/or the second variable (28), these adaptation means (42, 72) being recurrent and automatic for said variable (27, 28),
• characterized in that said adaptation means (42, 72) are adapted to calculate a coefficient of modulation (42, 73) and to apply it as a multiplier to the variable (27, 28) in order to correct it.