Method of operating a fuel injector
AssigneesCaterpillar Inc., Lucas Industries public limited company
InventorsGlen F. Forck, Umesh Shah
Life of this patent
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Abstract
A method of operating a fuel injector comprises the steps of applying a test waveform to a solenoid coil of the injector to cause a response by an armature assembly and measuring the response of the armature assembly while the test waveform is applied to the solenoid coil. A control waveform for the injector is developed as a function of the variation of the measured response of the armature from a selected operational characteristic. The developed control waveform is thereafter applied to the solenoid coil to cause the armature assembly to approach a nominal position.
Claims19
A method of operating a fuel injector to achieve a predetermined desired operational characteristic, the fuel injector including a spill valve, a direct operated check (DOC) valve, and a solenoid having a solenoid coil and an armature assembly movable through a range of positions including a first position to close the spill valve to cause fuel pressurization and a second position to close the DOC valve to cause fuel injection, the method comprising the steps of:
- determining a variation of a measured fuel pressurization characteristic of the fuel injector from a predetermined desired fuel pressurization characteristic by:
- (a) applying a test waveform to the solenoid coil to cause a movement by the armature assembly to the first position;
- (b) detecting the movement of the armature assembly while the test waveform is applied to the solenoid coil to determine the measured fuel pressurization characteristic of the fuel injector;
- and (c) determining the variation between the measured fuel pressurization characteristic and the predetermined desired fuel pressurization characteristic;
- developing a control waveform as a function of the variation between the measured fuel pressurization characteristic and the predetermined desired fuel pressurization characteristic;
- and
- thereafter applying the developed control waveform to the solenoid coil to cause the armature assembly to approach the first position to close the spill valve such that the fuel injector achieves the predetermined desired fuel pressurization characteristic.
A method of operating a fuel injector to compensate for individual characteristics thereof, the fuel injector including a spill valve, a direct operated check (DOC) valve, and a solenoid having a solenoid coil and an armature assembly movable to a first position to cause fuel pressurization and a second position to cause fuel injection when a nominal control waveform is applied to the solenoid coil, the method comprising the steps of:
- applying the nominal control waveform to the solenoid coil to move the armature assembly to the first position;
- detecting the movement of the armature assembly while the nominal control waveform is applied to the solenoid coil to determine a measured fuel pressurization characteristic of the fuel injector;
- developing an adjusted control waveform as a function of a variation of the measured fuel pressurization characteristic from a desired fuel pressurization characteristic;
- and
- after inserting the fuel injector into an engine, applying the adjusted control waveform to the solenoid coil to cause the armature assembly to approach the first position to produce the desired fuel pressurization characteristic.
Dependencies are inferred from the claim text.