Method of operating a fuel injector, a control unit that performs the method, and a system that includes the control unit
AssigneeSentec Ltd
InventorAndrew Dames
Life of this patent
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Abstract
A solenoid actuator is described. The solenoid actuator comprises an armature, pole piece(s), electromagnet coil(s) arranged, in response to energization, to cause travel of the armature between first and second positions along a direction of travel, permanent magnet(s) positioned and orientated for latching the armature in at least the first position when the armature is in the first position and spring(s) arranged to bias the armature. The solenoid actuator can be operated to provide partial lift.
Claims29
A method of operating a fuel injector comprising a solenoid actuator comprising an armature, pole piece(s), electromagnet coil(s) arranged, in response to energisation, to cause travel of the armature between first and second positions along a direction of travel, and spring(s) arranged to bias the armature, wherein in the first position the fuel injector is closed and wherein quasi-static position of the armature is at least monotonic with the coil current over all or some of length of travel of the armature, the method comprising:
- applying, in a cycle, drive waveform(s) to the electromagnet coil(s), the drive waveform(s) including turn-on drive waveform(s) having profile(s) and duration so as to position the armature at a position between the first and second positions and at which the armature is at rest, and turn-off drive waveform(s) having profile(s) and duration so as to cause the armature to move towards the first position;
- obtaining measurement(s) of at least one of back emf, current, and resistance from the electromagnet coil(s);
- and
- adjusting the drive waveform(s) applied to the electromagnetic coil(s) in at least one of the cycle and a subsequent cycle using the measurement(s).
Dependencies are inferred from the claim text.