Adaptive fuel direct injection system
View Patent ↗A direct fuel injection system including a common rail and control unit, a pump, an on/off valve, controlled by the control unit, to regulate the volume of fuel sent to the pump to be fed into the common rail, the control unit including: first determination elements for determining a peak phase duration during which a command must be applied to the valve to obtain a peak current to cause a change of state of the valve; second determination elements for determining a holding ratio according to which a command must be applied to the valve, after its change of state, to maintain a holding current necessary to maintain the state of the valve; application elements for applying the command to the valve first continuously during the peak phase duration and then by pulse width modulation according to the holding ratio; and at least one recurrent and automatic adaptation element.
1. 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 ) that determines a peak phase duration ( 27 ) during which a first command must be applied to the valve ( 3 ), and thereby obtains a peak current ( 38 , 60 ) greater than or equal to a reference peak current ( 61 ) necessary to cause a change of state of the valve ( 3 );
second determination means ( 70 ) that determines a holding ratio ( 28 ) in accordance with which a second command must be applied to the valve ( 3 ), after a change of state of the valve, thereby maintaining a holding current ( 39 , 90 ) greater than or equal to a reference holding current ( 91 ) necessary to maintain said state of the valve ( 3 );
application means that applies said first command to said valve ( 3 ) continuously during said peak phase duration ( 27 ), and then said second command by pulse width modulation in accordance with said holding ratio ( 28 ); and
adaptation means ( 42 , 72 ) that corrects any of the peak phase duration ( 27 ) and the holding ratio ( 28 ) in a recurrent and automatic manner,
wherein said adaptation means ( 42 , 72 ) calculate a coefficient of modulation ( 43 , 73 ) and apply the calculated coefficient of modulation as a multiplier to any of the peak phase duration ( 27 ) and the holding ratio ( 28 ) to generate one of a corrected peak phase duration and a corrected holding ratio.
2. The system as claimed in claim 1 , wherein said adaptation means ( 42 , 72 ) further include calculation means ( 44 , 74 ) adapted to calculate said coefficient of modulation ( 43 , 73 ) in a recurrent manner as a function of a preceding value of said coefficient of modulation ( 63 , 93 ) and a difference between one of the peak current ( 38 , 60 ) and the holding current ( 39 , 90 ), and a corresponding one of the reference peak current ( 61 ) and the reference holding current ( 91 ).
3. The system as claimed in claim 2 , wherein said calculation means ( 44 , 74 ) are adapted to apply the formula:
CM
(
n
)
=
CM
(
n
-
1
)
+
G
·
Vref
(
n
)
-
V
(
n
)
Vref
(
n
)
in which
CM(n) is the coefficient of modulation ( 43 , 73 ) at the time n,
CM(n−1) is the coefficient of modulation ( 63 , 93 ) at the preceding time n−1,
G is a gain ( 62 , 92 ),
V(n) is one of the peak current ( 38 , 60 ) and the holding current ( 39 , 90 ) at the time n, and
Vref(n) is one of the reference peak current ( 61 ) and the reference holding current ( 91 ) corresponding to at the time n.
4. The system as claimed in claim 2 , wherein the calculation means ( 44 , 74 ) recalculate the coefficient of modulation ( 43 , 73 ) periodically.
5. The system as claimed in claim 2 , wherein the calculation means ( 44 , 74 ) recalculate the coefficient of modulation ( 43 , 73 ) if any of the peak current ( 38 , 60 ) and the holding current ( 39 , 90 ) departs from a predefined range.
6. The system as claimed in claim 3 , wherein the calculation means ( 44 , 74 ) recalculate the coefficient of modulation ( 43 , 73 ) periodically.
7. The system as claimed in claim 3 , wherein the calculation means ( 44 , 74 ) recalculate the coefficient of modulation ( 43 , 73 ) if V(n) departs from a predefined range.
8. The system as claimed in claim 4 , wherein the calculation means ( 44 , 74 ) recalculate the coefficient of modulation ( 43 , 73 ) if any of the peak current ( 38 , 60 ) and the holding current ( 39 , 90 ) departs from a predefined range.
9. A direct fuel injection system, comprising:
a common rail ( 4 );
a control unit ( 1 );
a pump ( 2 ); and
a valve ( 3 ), controlled on an on-or-off basis by the control unit ( 1 ) to regulate a volume of fuel sent to the pump ( 2 ) to be fed into the common rail ( 4 ),
wherein said control unit ( 1 ) comprises:
a first determiner means ( 40 ) that determines a peak phase duration ( 27 ) during which a first command must be applied to the valve ( 3 ), and thereby obtains a peak phase duration ( 27 ) greater than or equal to a reference peak current ( 61 ) necessary to cause a change of state of the valve ( 3 );
a second determiner means ( 70 ) that determines a holding ratio ( 28 ) in accordance with which a second command must be applied to the valve ( 3 ), after a change of state of the valve, thereby maintaining a holding current ( 39 , 90 ) greater than or equal to a reference holding current ( 91 ) necessary to maintain said state of the valve ( 3 );
an applicator that applies said first command to said valve ( 3 ) continuously during said peak peak phase duration, and then said second command by pulse width modulation in accordance with said holding ratio ( 28 ); and
an adapter ( 42 , 72 ) that corrects any of the peak phase duration ( 27 ) and the holding ratio ( 28 ) in a recurrent and automatic manner, and
wherein said adapter ( 42 , 72 ) calculate a coefficient of modulation ( 43 , 73 ) and apply the calculated coefficient of modulation as a multiplier to any of the peak phase duration ( 27 ) and the holding ratio ( 28 ) to generate one of a corrected peak phase duration and a corrected holding ratio.
10. A method for controlling a direct fuel injection system that includes a common rail ( 4 ) with 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 ), comprising:
determining a peak phase duration ( 27 ) during which a first command must be applied to the valve ( 3 ), and thereby obtains a peak current ( 38 , 60 ) greater than or equal to a reference peak current ( 61 ) necessary to cause a change of state of the valve ( 3 );
determining a holding ratio ( 28 ) in accordance with which a second command must be applied to the valve ( 3 ), after a change of state of the valve, thereby maintaining a holding current ( 39 , 90 ) greater than or equal to a reference holding current ( 91 ) necessary to maintain said state of the valve ( 3 );
applying said first command to said valve ( 3 ) continuously during said peak phase duration ( 27 ), and then said second command by pulse width modulation in accordance with said holding ratio ( 28 ); and
correcting any of the peak phase duration ( 27 ) and the holding ratio ( 28 ) in a recurrent and automatic manner,
wherein said correction step includes calculating a coefficient of modulation ( 43 , 73 ) and applying the calculated coefficient of modulation as a multiplier to any of the peak phase duration ( 27 ) and the holding ratio ( 28 ) to generate one of a corrected peak phase duration and a corrected holding ratio.