METHOD FOR CONTROLLING A FUEL INJECTOR

1 . Method for determining injected fuel mass delivered from an electromagnetic solenoid-activated fuel injector during a fuel injection event, comprising:

determining a sensed injection duration and a maximum injection mass flowrate during the fuel injection event; and

determining the injected fuel mass for the fuel injection event based on the sensed injection duration and the maximum injection mass flowrate during the fuel injection event.

2 . The method of claim 1 , wherein determining the injected fuel mass for the fuel injection event comprises calculating the injected fuel mass in accordance with the following relationship:

M _Inj= K 2*( T _Inj* M max)

wherein

M_Inj is the injected fuel mass,

T_Inj is the sensed injection duration,

MMax is the maximum injection mass flowrate, and

K2 is a scalar term.

3 . The method of claim 2 , wherein the K2 scalar term is determined in relation to a fuel pressure.

4 . The method of claim 1 , wherein determining the sensed injection duration comprises:

determining a first time point corresponding to a discernible decrease in a fuel pressure;

determining a second time point corresponding to a discernible inflection point in an injector voltage; and

calculating the sensed injection duration as an elapsed time period between the first and second time points.

5 . The method of claim 4 , wherein said fuel pressure comprises a fuel pressure proximal to the fuel injector.

6 . The method of claim 1 , wherein determining the maximum injection mass flowrate comprises:

detecting a maximum drop in a fuel pressure during the fuel injection event; and

determining the maximum injection mass flowrate based on the maximum pressure drop in the fuel pressure during the fuel injection event.

7 . The method of claim 1 , further comprising correlating the injected fuel mass for the fuel injection event to an injector command signal for the fuel injection event.

8 . Method for operating a fuel injector, comprising:

determining a sensed injection duration for a fuel injection event comprising an elapsed time period between a discernible decrease in a fuel pressure and a discernible inflection point in an injector voltage;

determining a maximum injection mass flowrate based on a maximum pressure drop in the fuel pressure during the fuel injection event; and

determining an injected fuel mass for the fuel injection event based on the sensed injection duration and the maximum injection mass flowrate.

9 . The method of claim 8 , wherein determining the injected fuel mass for the fuel injection event comprises calculating the injected fuel mass in accordance with the following relationship:

M _Inj= K 2*( T _Inj* M max)

wherein

M_Inj is the injected fuel mass,

T_Inj is the sensed injection duration,

MMax is the maximum injection mass flowrate, and

K2 is a scalar term.

10 . The method of claim 9 , wherein the K2 scalar term is determined in relation to the fuel pressure.

11 . The method of claim 8 , wherein determining the sensed injection duration comprises:

monitoring the fuel pressure at a point proximal to the fuel injector and the injector voltage;

determining a first time point corresponding to the discernible decrease in the fuel pressure;

determining a second time point corresponding to the discernible inflection point in the injector voltage; and

calculating the sensed injection duration as an elapsed time period between the first and second time points.

12 . The method of claim 8 , wherein determining the maximum injection mass flowrate comprises:

monitoring the fuel pressure proximal to the fuel injector;

detecting the maximum drop in the fuel pressure during the fuel injection event; and

determining the maximum injection mass flowrate during the fuel injection event based on the maximum pressure drop in the fuel pressure during the fuel injection event.

13 . Method for operating an electromagnetic solenoid-activated fuel injector, comprising:

determining an elapsed time period comprising a time period between a discernible decrease in a fuel pressure proximal to the fuel injector and a discernible inflection point in an injector voltage during a fuel injection event;

determining a maximum pressure drop in the fuel pressure during the fuel injection event; and

determining an injected fuel mass based on the elapsed time period and the maximum pressure drop in the fuel pressure.

14 . The method of claim 13 , wherein determining the injected fuel mass comprises calculating the injected fuel mass in accordance with the following relationship:

M _Inj= K 2*( T _Inj* M max)

wherein

M_Inj is the injected fuel mass,

T_Inj is the elapsed time period,

MMax is a maximum injection mass flowrate corresponding to the maximum pressure drop in the fuel pressure during the fuel injection event, and

K2 is a scalar term.

15 . The method of claim 14 , wherein the K2 scalar term is determined in relation to the fuel pressure.