阅读说明：本技术 流体喷射装置的指纹识别 (Fingerprint identification for fluid ejection devices ) 是由 K.E.沙赫劳迪 S.奈尔 于 2018-02-27 设计创作，主要内容包括：本说明书的主题尤其可以在用于表征流体喷射器的方法中具体实施,该方法包括：接收波形数据集合；识别拉动轨迹；确定检测阈值水平值；识别数据集合中的第一子集,该第一子集代表电波形集合中的所选第一电波形；识别打开值；识别代表性关闭值；识别锚定值；基于数据集合、拉动轨迹、第一子集和打开值来识别数据集合中的第二子集；识别最大电值；基于数据集合、锚定值和最大电值来识别打开轨迹；识别保持值；以及提供与流体喷射器相关联的特性,所述特性包括拉动轨迹、打开轨迹、保持值、锚定值和代表性关闭值。(The subject matter of this specification can be embodied in, among other things, a method for characterizing a fluid ejector, the method comprising: receiving a set of waveform data; recognizing a pulling track; determining a detection threshold level value; identifying a first subset of the set of data, the first subset representing a selected first electrical waveform of the set of electrical waveforms; identifying an opening value; identifying a representative shutdown value; identifying an anchor value; identifying a second subset of the set of data based on the set of data, the pull trajectory, the first subset, and the opening value; identifying a maximum electrical value; identifying an opening trajectory based on the data set, the anchor value, and the maximum electrical value; identifying a hold value; and providing characteristics associated with the fluid ejector, the characteristics including a pull trajectory, an open trajectory, a hold value, an anchor value, and a representative close value.)

1. A computer-implemented method for characterizing a fluid ejector, the method comprising:

Receiving a data set representative of a plurality of electrical waveforms, each waveform corresponding to a selected magnitude of electrical stimulation provided to an actuator of a fluid ejector;

Identifying a pull trajectory based on the set of data;

Determining a detection threshold level value based on the data set;

Identifying a first subset of the set of data based on the detection threshold level value and the set of data, the first subset representing a selected first electrical waveform of the plurality of electrical waveforms;

Identifying a representative open value based on the set of data;

Identifying a representative close value based on the representative open value and the data set;

identifying an anchor value based on the set of data and the first subset;

Identifying a second subset of the set of data based on the set of data, the pull trajectory, the first subset, and the representative opening value, the second subset representing a selected second electrical waveform of the plurality of electrical waveforms;

Identifying a maximum electrical value based on the second subset;

identifying an opening trajectory based on the data set, the anchor value, and the maximum electrical value;

identifying a retention value based on the set of data; and

providing characteristics associated with the fluid ejector, the characteristics including the pull trajectory, the open trajectory, the hold value, the anchor value, and the representative close value.

2. The method of claim 1, wherein the plurality of electrical waveforms are current waveforms of the fluid injector, the set of data is a first set of fluid injector current measurements representative of the current waveforms, the pull trajectory is a second set of fluid injector current measurements, the representative opening value is a first fluid injector current measurement, the anchor value is a second fluid injector current measurement, the maximum electrical value is a third fluid injector current measurement, and the opening trajectory is a third set of fluid injector current measurements.

3. The method of claim 1 or 2, wherein identifying a pull trajectory further comprises:

Selecting one or more third subsets of the data set, each of the selected subsets representing a successive pair of the plurality of waveforms, each selected pair representing an electrical waveform successive in two amplitudes;

For each of the selected third subsets:

Determining a differential waveform based on a difference between the pair of waveforms;

Determining that the differential waveform includes a zero crossing point; and

Identifying and assigning a local maximum in a temporal aspect of the second waveform in the selected pair to a fourth subset of data; and

providing the fourth subset as a pull trajectory associated with the fluid ejector.

4. the method of claim 3, wherein the first local maximum in time is an effect of a solenoid armature of the fluid injector beginning to move relative to a de-energized state of the fluid injector.

5. The method of claim 3 or 4, wherein identifying the second subset of the set of data further comprises:

Identifying a last value of the pull trajectory;

Identifying a subset of the set of data that corresponds to the last value; and

Providing the identified subset as the second subset.

6. the method of any of claims 1-5, wherein identifying the anchor value further comprises: selecting one or more third subsets of the data set, each of the selected subsets representing a successive pair of the plurality of waveforms, each selected pair representing an electrical waveform successive in two amplitudes;

For each of the selected third subsets:

Determining a differential waveform based on a difference between the pair of waveforms;

Determining that the differential waveform is the first differential waveform that will include a zero crossing point; and

Providing the zero crossing point as the anchor value associated with the fluid ejector.

7. the method of any of claims 1-6, wherein identifying the opening trajectory further comprises:

selecting one or more third subsets of the data sets, each of the selected subsets representing a successive pair of the plurality of waveforms, each selected pair representing an electrical waveform of the fluid ejector that is successive in two amplitudes;

For each of the selected third subsets:

Determining a differential waveform based on a difference between the pair of waveforms;

adding the determined differential waveform to a set of differential waveform data;

Identifying the anchor point within the set of differential waveform data;

Identifying the maximum electrical value within the set of differential waveform data;

Determining a mathematical expression for a line between the anchor value and the maximum electrical value within the set of differential waveform data;

Identifying a set of values within the set of differential values that intersect the mathematical expression; and

Providing the identified set of values as the opening trajectory associated with the fluid ejector.

8. the method of any of claims 1-7, wherein determining a detection threshold level value further comprises: a nominal noise level of one or more of the plurality of electrical waveforms is estimated.

9. the method of any one of claims 1 to 8, further comprising: actuating a solenoid of the fluid injector with a solenoid actuation waveform based on the representative opening value associated with the fluid injector.

10. The method of any of claims 1-9, wherein identifying the hold value further comprises:

identifying a first stabilizing waveform for the fluid ejector, the first stabilizing waveform comprising values described by the pull trajectory and satisfying one or more stabilization criteria;

Determining a minimum electrical value based on the first stabilizing waveform; and

Providing the minimum electrical value as the hold value associated with the fluid ejector.

11. A system for characterizing an injector for a fluid injector, the system comprising:

A data processing device; and

Computer memory storage storing instructions executable by a computer device and that upon such execution cause the computer device to perform operations comprising:

Receiving a data set representative of a plurality of electrical waveforms, each waveform corresponding to a selected magnitude of electrical stimulation provided to an actuator of a fluid ejector;

identifying a pull trajectory based on the set of data;

Determining a detection threshold level value based on the data set;

Identifying a first subset of the set of data based on the detection threshold level value and the set of data, the first subset representing a selected first electrical waveform of the plurality of electrical waveforms;

Identifying a representative open value based on the set of data;

Identifying a representative close value based on the representative open value and the data set;

Identifying an anchor value based on the set of data and the first subset;

Identifying a second subset of the set of data based on the set of data, the pull trajectory, the first subset, and the representative opening value, the second subset representing a selected second electrical waveform of the plurality of electrical waveforms;

Identifying a maximum electrical value based on the second subset;

identifying an opening trajectory based on the data set, the anchor value, and the maximum electrical value;

identifying a retention value based on the set of data; and

Providing characteristics associated with the fluid ejector, the characteristics including the pull trajectory, the open trajectory, the hold value, the anchor value, and the representative close value.

12. The system of claim 11, wherein the plurality of electrical waveforms are current waveforms of the fluid injector, the set of data is a first set of fluid injector current measurements representative of the current waveforms, the pull trajectory is a second set of fluid injector current measurements, the representative opening value is a first fluid injector current measurement, the anchor value is a second fluid injector current measurement, the maximum electrical value is a third fluid injector current measurement, and the opening trajectory is a third set of fluid injector current measurements.

13. The system of claim 11 or 12, wherein identifying a pull trajectory further comprises:

Selecting one or more third subsets of the data set, each of the selected subsets representing a successive pair of the plurality of waveforms, each selected pair representing an electrical waveform successive in two amplitudes;

For each of the selected third subsets:

determining a differential waveform based on a difference between the pair of waveforms;

Determining that the differential waveform includes a zero crossing point; and

identifying and adding a local maximum in time aspect of the second waveform in the selected pair to a fourth subset of data; and

providing the fourth subset as a pull trajectory associated with the fluid ejector.

14. The system of claim 13, wherein the first local maximum in time is an effect of a solenoid armature of the fluid injector beginning to move relative to a de-energized state of the fluid injector.

15. the system of claim 13 or 14, wherein identifying a second subset of the set of data further comprises:

Identifying a last value of the pull trajectory;

identifying a subset of the set of data that corresponds to the last value; and

Providing the identified subset as the second subset.

16. The system of any of claims 11 to 15, wherein identifying the anchor value further comprises: selecting one or more third subsets of the data set, each of the selected subsets representing a successive pair of the plurality of waveforms, each selected pair representing an electrical waveform successive in two amplitudes;

For each of the selected third subsets:

Determining a differential waveform based on a difference between the pair of waveforms;

Determining that the differential waveform is the first differential waveform that will include a zero crossing point; and

Providing the zero crossing point as the anchor value associated with the fluid ejector.

17. the system of any of claims 11 to 16, wherein identifying the opening trajectory further comprises:

Selecting one or more third subsets of the data sets, each of the selected subsets representing a successive pair of the plurality of waveforms, each selected pair representing an electrical waveform of the fluid ejector that is successive in two amplitudes;

For each of the selected third subsets:

determining a differential waveform based on a difference between the pair of waveforms;

Adding the determined differential waveform to a set of differential waveform data;

identifying the anchor point within the set of differential waveform data;

Identifying the maximum electrical value within the set of differential waveform data;

Determining a mathematical expression for a line between the anchor value and the maximum electrical value within the set of differential waveform data;

Identifying a set of values within the set of differential values that intersect the mathematical expression; and

Providing the identified set of values as the opening trajectory associated with the fluid ejector.

18. The system of any of claims 11 to 17, wherein determining a detection threshold level value further comprises: a nominal noise level of one or more of the plurality of electrical waveforms is estimated.

19. The system of any one of claims 11 to 18, further comprising: actuating a solenoid of the fluid injector with a solenoid actuation waveform based on the representative opening value associated with the fluid injector.

20. the system of any of claims 11 to 19, wherein identifying the hold value further comprises:

identifying a first stabilizing waveform for the fluid ejector, the first stabilizing waveform comprising values described by the pull trajectory and satisfying one or more stabilization criteria;

Determining a minimum electrical value based on the first stabilizing waveform; and

Providing the minimum electrical value as the hold value associated with the fluid ejector.

Technical Field

The present description relates to determining an electromechanical response of a fluid injector.

background

solenoid operated gas or liquid fluid valves use a form of electromagnetic actuation. These mechanisms generally include a coil and an armature that is free to move and is actuated by the magnetic pull force generated by the coil when the coil carries current. The armature is typically spring loaded away from the energized position such that when a power pulse is applied to the coil, the armature is pulled into the energized position and opens or closes the valve when moved. Generally, once the armature of a solenoid has moved to the end of its operating stroke, the armature does no further work.

A solenoid is often combined with an on/off valve whereby the valve is pulled by the solenoid (when energized) and returned by a spring (when de-energized). The valve attached to the solenoid may be closed in one position and open in a second position, or it may be a switching valve with two valve seats. In some applications (such as fuel injectors), it is desirable to measure the timing of the open and closed positions of a solenoid operated valve for control and diagnostic purposes.

Diesel and gasoline fuel injectors are required to have precise operating times. The valve determines the fuel injection timing. The valve controller also determines a fuel injection duration that affects an amount of fuel injected into a cylinder of the diesel, gasoline, or dual-fuel engine. The performance of the engine (balance between cylinders, power, fuel consumption, emissions and efficiency) is thus affected.

disclosure of Invention

In general, this document describes systems and techniques for determining an electromechanical response of a fluid injector.

A computer-implemented method for characterizing a fluid ejector, comprising: receiving a set of data representative of a set of electrical waveforms, each waveform corresponding to a selected magnitude of electrical stimulation provided to an actuator of a fluid ejector; identifying a pull trajectory based on the set of data; determining a detection threshold level value based on the data set; identifying a first subset of the set of data based on the detection threshold level value and the set of data, the first subset representing a selected first electrical waveform of the set of electrical waveforms; identifying a representative open value based on the data set; identifying a representative close value based on the representative open value and the data set; identifying an anchor value based on the set of data and the first subset; identifying a second subset of the set of data based on the set of data, the pull trajectory, the first subset, and the representative opening value, the second subset representing a selected second electrical waveform of the set of electrical waveforms; identifying a maximum electrical value based on the second subset; identifying an opening trajectory based on the data set, the anchor value, and the maximum electrical value; identifying a retention value based on the data set; and providing characteristics associated with the fluid ejector, the characteristics including a pull trajectory, an open trajectory, a hold value, an anchor value, and a representative close value.

Various implementations may include some, all, or none of the following features. The set of electrical waveforms may be a current waveform of the fluid injector, the set of data may be a first set of fluid injector current measurements representative of the current waveform, the pull trajectory may be a second set of fluid injector current measurements, the representative opening value may be the first fluid injector current measurement, the anchor value may be the second fluid injector current measurement, the maximum electrical value may be a third fluid injector current measurement, and the opening trajectory may be the third set of fluid injector current measurements. Identifying the pull trajectory may include: selecting one or more third subsets of the data sets, each of the selected subsets representing a successive pair of the waveform sets, each selected pair representing an electrical waveform successive in two amplitudes (magnitude-wise); for each of the selected third subsets: determining a differential waveform based on a difference between the pair of waveforms; determining that the differential waveform includes a zero crossing point; and identifying and adding a local maximum in time aspect of the second waveform in the selected pair to a fourth subset of data; and providing the fourth subset as a pull trajectory associated with the fluid ejector. The first local maximum in time may be an effect of a solenoid armature of the fluid injector beginning to move relative to a de-energized state of the fluid injector. Identifying the second subset of the set of data may include: identifying a final value of a pull trajectory; identifying a subset of the data set corresponding to the last value; and providing the identified subset as the second subset. Identifying the anchor value may include: selecting one or more third subsets of the data sets, each of the selected subsets representing a successive pair of the waveform sets, each of the selected pairs representing electrical waveforms that are successive in terms of two amplitudes; for each of the selected third subsets: determining a differential waveform based on a difference between the pair of waveforms; determining that the differential waveform is a first differential waveform that will include a zero crossing point; and providing the zero crossing point as an anchor value associated with the fluid ejector. Identifying an opening trajectory may include: selecting one or more third subsets of the data sets, each of the selected subsets representing a successive pair of the waveform sets, each of the selected pairs representing electrical waveforms of the fluid injector that are successive in two amplitudes; for each of the selected third subsets: determining a differential waveform based on a difference between the pair of waveforms; adding the determined differential waveform to a set of differential waveform data; identifying an anchor point within the set of differential waveform data; identifying a maximum electrical value within the set of differential waveform data; determining a mathematical expression of a line between an anchor value and a maximum electrical value within the differential waveform data set; identifying a set of values within the set of differential values that intersect the mathematical expression; and providing the identified set of values as an opening trajectory associated with the fluid injector. Determining the detection threshold level value may include: a nominal noise level of one or more electrical waveforms in the set of electrical waveforms is estimated. The method can comprise the following steps: a solenoid of the fluid injector is actuated with a solenoid actuation waveform based on a representative opening value associated with the fluid injector. Identifying the retention value may include: identifying a first stabilizing waveform for the fluid ejector, the first stabilizing waveform comprising values described by the pull trajectory and satisfying one or more stabilization criteria; determining a minimum electrical value based on the first stabilizing waveform; and providing the minimum electrical value as a hold value associated with the fluid ejector.

A system for characterizing an injector for a fluid injector is disclosed, the system comprising: a data processing device; and computer memory storage storing instructions executable by the computer apparatus and that, upon such execution, cause the computer apparatus to perform operations comprising: receiving a set of data representative of a set of electrical waveforms, each waveform corresponding to a selected magnitude of electrical stimulation provided to an actuator of a fluid ejector; identifying a pull trajectory based on the set of data; determining a detection threshold level value based on the data set; identifying a first subset of the set of data based on the detection threshold level value and the set of data, the first subset representing a selected first electrical waveform of the set of electrical waveforms; identifying a representative open value based on the data set; identifying a representative close value based on the representative open value and the data set; identifying an anchor value based on the set of data and the first subset; identifying a second subset of the set of data based on the set of data, the pull trajectory, the first subset, and the representative opening value, the second subset representing a selected second electrical waveform of the set of electrical waveforms; identifying a maximum electrical value based on the second subset; identifying an opening trajectory based on the data set, the anchor value, and the maximum electrical value; identifying a retention value based on the data set; and providing characteristics associated with the fluid ejector, the characteristics including a pull trajectory, an open trajectory, a hold value, an anchor value, and a representative close value.

various embodiments may include some, all, or none of the following features. The set of electrical waveforms may be a current waveform of the fluid injector, the set of data may be a first set of fluid injector current measurements representative of the current waveform, the pull trajectory may be a second set of fluid injector current measurements, the representative opening value may be the first fluid injector current measurement, the anchor value may be the second fluid injector current measurement, the maximum electrical value may be a third fluid injector current measurement, and the opening trajectory may be the third set of fluid injector current measurements. Identifying the pull trajectory may include: selecting one or more third subsets of the data set, each of the selected subsets representing a successive pair of the waveform set, each of the selected pairs representing electrical waveforms that are successive in terms of two amplitudes; for each of the selected third subsets: determining a differential waveform based on a difference between the pair of waveforms; determining that the differential waveform includes a zero crossing point; and identifying and adding a local maximum in time aspect of the second waveform in the selected pair to a fourth subset of data; and providing the fourth subset as a pull trajectory associated with the fluid ejector. The first local maximum in time may be an effect of a solenoid armature of the fluid injector beginning to move relative to a de-energized state of the fluid injector. Identifying the second subset of the set of data may include: identifying a final value of a pull trajectory; identifying a subset of the data set corresponding to the last value; and providing the identified subset as a second subset. Identifying the anchor value may include: selecting one or more third subsets of the data sets, each of the selected subsets representing a successive pair of the waveform set, each of the selected pairs representing electrical waveforms that are successive in terms of two amplitudes; for each of the selected third subsets: determining a differential waveform based on a difference between the pair of waveforms; determining that the differential waveform is a first differential waveform that will include a zero crossing point; and providing the zero crossing point as an anchor value associated with the fluid ejector. Identifying an opening trajectory may include: selecting one or more third subsets of the data sets, each of the selected subsets representing a successive pair of the waveform set, each of the selected pairs representing electrical waveforms of the fluid injector that are successive in two amplitudes; for each of the selected third subsets: determining a differential waveform based on a difference between the pair of waveforms; adding the determined differential waveform to a set of differential waveform data; identifying an anchor point within the set of differential waveform data; identifying a maximum electrical value within the set of differential waveform data; determining a mathematical expression of a line between an anchor value and a maximum electrical value within the differential waveform data set; identifying a set of values within the set of differential values that intersect the mathematical expression; and providing the identified set of values as an opening trajectory associated with the fluid ejector. Determining the detection threshold level value may include: a nominal noise level of one or more electrical waveforms in the set of electrical waveforms is estimated. The system may include: a solenoid of the fluid injector is actuated with a solenoid actuation waveform based on a representative opening value associated with the fluid injector. Identifying the retention value may include: identifying a first stabilizing waveform for the fluid ejector, the first stabilizing waveform comprising values described by the pull trajectory and satisfying one or more stabilization criteria; determining a minimum electrical value based on the first stabilizing waveform; and providing the minimum electrical value as a hold value associated with the fluid ejector.

in a first aspect, a computer-implemented method for characterizing a fluid ejector includes: receiving a data set representative of a plurality of electrical waveforms, each waveform corresponding to a selected magnitude of electrical stimulation provided to an actuator of a fluid ejector; identifying a pull trajectory based on the set of data; determining a detection threshold level value based on the data set; identifying a first subset of the data set based on the detection threshold level value and the data set, the first subset representing a selected first electrical waveform of the plurality of electrical waveforms; identifying a representative open value based on the data set; identifying a representative close value based on the representative open value and the data set; identifying an anchor value based on the set of data and the first subset; identifying a second subset of the data set based on the data set, the pull trajectory, the first subset, and the representative opening value, the second subset representing a selected second electrical waveform of the plurality of electrical waveforms; identifying a maximum electrical value based on the second subset; identifying an opening trajectory based on the data set, the anchor value, and the maximum electrical value; identifying a retention value based on the data set; and providing characteristics associated with the fluid ejector, the characteristics including a pull trajectory, an open trajectory, a hold value, an anchor value, and a representative close value.

In a second aspect, according to aspect 1, the plurality of electrical waveforms are current waveforms of the fluid injector, the data set is a first set of fluid injector current measurements representative of the current waveforms, the pull trajectory is a second set of fluid injector current measurements, the representative opening value is the first fluid injector current measurement, the anchor value is the second fluid injector current measurement, the maximum electrical value is the third fluid injector current measurement, and the opening trajectory is the third set of fluid injector current measurements.

In a third aspect, according to aspect 1 or 2, identifying the pull trajectory further comprises: selecting one or more third subsets of the data sets, each of the selected subsets representing a successive pair of the plurality of waveforms, each of the selected pairs representing electrical waveforms that are successive in terms of two amplitudes; for each of the selected third subsets: determining a differential waveform based on a difference between the pair of waveforms; determining that the differential waveform includes a zero crossing point; and identifying and adding a local maximum in time aspect of the second waveform in the selected pair to a fourth subset of data; and providing the fourth subset as a pull trajectory associated with the fluid ejector.

in a fourth aspect, according to aspect 3, the first local maximum in terms of time is an effect of a solenoid armature of the fluid injector beginning to move relative to a de-energized state of the fluid injector.

in a fifth aspect, according to aspect 3 or 4, identifying the second subset of the set of data further comprises: identifying a final value of a pull trajectory; identifying a subset of the data set corresponding to the last value; and providing the identified subset as the second subset.

In a sixth aspect, according to any one of aspects 1 to 5, identifying the anchor value further comprises: selecting one or more third subsets of the data sets, each of the selected subsets representing a successive pair of the plurality of waveforms, each of the selected pairs representing electrical waveforms that are successive in terms of two amplitudes; for each of the selected third subsets: determining a differential waveform based on a difference between the pair of waveforms; determining that the differential waveform is a first differential waveform that will include a zero crossing point; and providing the zero crossing point as an anchor value associated with the fluid ejector.

in a seventh aspect, according to any one of aspects 1 to 6, identifying an opening trajectory further comprises: selecting one or more third subsets of the data sets, each of the selected subsets representing a successive pair of the plurality of waveforms, each of the selected pairs representing electrical waveforms of the fluid injector that are successive in two amplitudes; for each of the selected third subsets: determining a differential waveform based on a difference between the pair of waveforms; adding the determined differential waveform to a set of differential waveform data; identifying an anchor point within the set of differential waveform data; identifying a maximum electrical value within the set of differential waveform data; determining a mathematical expression of a line between an anchor value and a maximum electrical value within the differential waveform data set; identifying a set of values within the set of differential values that intersect the mathematical expression; and providing the identified set of values as an opening trajectory associated with the fluid ejector.

In an eighth aspect, according to any one of aspects 1 to 7, wherein determining the detection threshold level value further comprises: estimating a nominal noise level of one or more of the plurality of electrical waveforms.

In a ninth aspect, according to any one of aspects 1 to 8, further comprising: a solenoid of the fluid injector is actuated with a solenoid actuation waveform based on a representative opening value associated with the fluid injector.

in a tenth aspect, any of claims 1 to 9, wherein identifying a retention value further comprises: identifying a first stabilizing waveform for the fluid ejector, the first stabilizing waveform comprising values described by the pull trajectory and satisfying one or more stabilization criteria; determining a minimum electrical value based on the first stabilizing waveform; and providing the minimum electrical value as a hold value associated with the fluid ejector.

in an eleventh aspect, a system for characterizing an injector for a fluid injector, the system comprising: a data processing device; and computer memory storage storing instructions executable by the computer apparatus and that, upon such execution, cause the computer apparatus to perform operations comprising: receiving a data set representative of a plurality of electrical waveforms, each waveform corresponding to a selected magnitude of electrical stimulation provided to an actuator of a fluid ejector; identifying a pull trajectory based on the set of data; determining a detection threshold level value based on the data set; identifying a first subset of the data set based on the detection threshold level value and the data set, the first subset representing a selected first electrical waveform of the plurality of electrical waveforms; identifying a representative open value based on the data set; identifying a representative close value based on the representative open value and the data set; identifying an anchor value based on the set of data and the first subset; identifying a second subset of the data set based on the data set, the pull trajectory, the first subset, and the representative opening value, the second subset representing a selected second electrical waveform of the plurality of electrical waveforms; identifying a maximum electrical value based on the second subset; identifying an opening trajectory based on the data set, the anchor value, and the maximum electrical value; identifying a retention value based on the data set; and providing characteristics associated with the fluid ejector, the characteristics including a pull trajectory, an open trajectory, a hold value, an anchor value, and a representative close value.

In a twelfth aspect, according to aspect 11, the plurality of electrical waveforms are current waveforms of the fluid injector, the data set is a first set of fluid injector current measurements representative of the current waveforms, the pull trajectory is a second set of fluid injector current measurements, the representative opening value is the first fluid injector current measurement, the anchor value is the second fluid injector current measurement, the maximum electrical value is the third fluid injector current measurement, and the opening trajectory is the third set of fluid injector current measurements.

In a thirteenth aspect, according to aspect 11 or 12, the identifying the pull trajectory further comprises: selecting one or more third subsets of the data set, each of the selected subsets representing a successive pair of the plurality of waveforms, each of the selected pairs representing electrical waveforms that are successive in terms of two amplitudes; for each of the selected third subsets: determining a differential waveform based on a difference between the pair of waveforms; determining that the differential waveform includes a zero crossing point; and identifying and adding a local maximum in time aspect of the second waveform in the selected pair to a fourth subset of data; and providing the fourth subset as a pull trajectory associated with the fluid ejector.

In a fourteenth aspect, according to aspect 13, the first local maximum in terms of time is an effect of a solenoid armature of the fluid injector beginning to move relative to a de-energized state of the fluid injector.

in a fifteenth aspect, according to aspect 13 or 14, identifying the second subset of the set of data further comprises: identifying a final value of a pull trajectory; identifying a subset of the data set corresponding to the last value; and providing the identified subset as the second subset.

in a sixteenth aspect according to any one of aspects 11 to 15, wherein identifying the anchor value further comprises: selecting one or more third subsets of the data set, each of the selected subsets representing a successive pair of the plurality of waveforms, each of the selected pairs representing electrical waveforms that are successive in terms of two amplitudes; for each of the selected third subsets: determining a differential waveform based on a difference between the pair of waveforms; determining that the differential waveform is a first differential waveform to include a zero crossing point; and providing the zero crossing point as an anchor value associated with the fluid ejector.

In a seventeenth aspect, according to any one of aspects 11 to 16, identifying an opening trajectory further comprises: selecting one or more third subsets of the data sets, each of the selected subsets representing a successive pair of the plurality of waveforms, each of the selected pairs representing electrical waveforms of the fluid injector that are successive in two amplitudes; for each of the selected third subsets: determining a differential waveform based on a difference between the pair of waveforms; adding the determined differential waveform to a set of differential waveform data; identifying an anchor point within the set of differential waveform data; identifying a maximum electrical value within the set of differential waveform data; determining a mathematical expression of a line between an anchor value and a maximum electrical value within the differential waveform data set; identifying a set of values within the set of differential values that intersect the mathematical expression; and providing the identified set of values as an opening trajectory associated with the fluid ejector.

In an eighteenth aspect, according to any one of aspects 11 to 17, determining the detection threshold level value further comprises: estimating a nominal noise level of one or more of the plurality of electrical waveforms.

In a nineteenth aspect, according to any one of aspects 11 to 18, further comprising: a solenoid of the fluid injector is actuated with a solenoid actuation waveform based on a representative opening value associated with the fluid injector.

In a twentieth aspect, according to any one of claims 11 to 19, identifying the retention value further comprises: identifying a first stabilizing waveform for the fluid ejector, the first stabilizing waveform comprising values described by the pull trajectory and satisfying one or more stabilization criteria; determining a minimum electrical value based on the first stabilizing waveform; and providing the minimum electrical value as a hold value associated with the fluid ejector.

the systems and techniques described herein may provide one or more of the following advantages. First, the system may characterize mechanical movement of an armature component (e.g., a valve) of an injector to enable monitoring, diagnosis, and prognosis of such injectors. Second, the system may provide non-intrusive adaptive (e.g., dynamic) fuel control as the injector or other electromagnetic actuator ages. Third, the system may enable automated calibration of injectors or valves on the engine. Fourth, the system can achieve cylinder balancing in any injector and detect imbalances. Fifth, the system may determine information for diagnosing inaccurate fueling, such as spring failure, valve sticking, valve wear, electrical connector loosening, and control settings inaccuracies. Sixth, the system may determine information that may be used in the process to protect the engine from injector-related failures and to resist control leakage (run-off), drift, and other instabilities. Seventh, the system can determine bounce metrics such as how long the injector armature bounces, the time of the first bounce, and the armature settling time.

The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features and advantages will be apparent from the description and drawings, and from the claims.

drawings

FIG. 1 is a schematic diagram illustrating an example fluid intake system for a reciprocating engine.

FIG. 2 is a graph of an example current waveform for a fluid injector.

FIG. 3 is a graph of an example set of current waveforms for a fluid injector.

fig. 4 and 5 are diagrams of example pull trajectories.

FIG. 6 is a graph of an example right margin and an example right margin trajectory.

Fig. 7 and 8 are graphs of example sets of differential waveforms.

FIG. 9 is a graph illustrating an example set of waveforms and an example opening trajectory.

FIG. 10 is a graph illustrating an example set of waveforms, pull trajectory, right margin trajectory, current hold value, and an example open trajectory.

FIG. 11 is a graph illustrating an example actuator fingerprint.

FIG. 12 is a flow chart of an example process for determining a response of a fluid injector.

Detailed Description

this document describes systems and techniques for determining an individual fluid (e.g., fuel) injector electromechanical response map (hereinafter referred to as an injector "fingerprint"). Fluid injectors typically include an electromagnetic actuator with the addition of a mechanical fluid admission valve whose position controls the amount of fluid (e.g., fuel) injected (e.g., into an intake port in a combustion chamber of the engine or directly into the combustion chamber of the engine). In modern embodiments, the injector may include pressure regulation and direct delivery into the combustion chamber. In applications where the fluid delivery response of a fluid ejector is determined, a "fingerprint" is a representation of the electromechanical response of the entire fluid ejector. Such fingerprints represent unique electromagnetic and mechanical properties of the valve, the actuator used to drive the valve, the internal volume of the system, the geometry of the ports, the geometry of the passages, other combinations of geometric features, or combinations of these any other suitable variables that can determine the fluid delivery dynamics of the fluid delivered from the injector supply to the injector. For the purposes of this document, the term "injector" includes any electro-mechanical fluid control device, such as a fuel injector or a fluid injector.

Generally, to meet stringent emissions and efficiency requirements, engine controllers are designed to deliver precise amounts of fuel to each of one or more cylinders of a reciprocating engine at precise times within a combustion cycle. This is generally accomplished by adjusting the start and duration of the current waveform that actuates the solenoid operated fuel injector valve. The valve may be part of a single stage electro-hydraulic or electro-pneumatic injection system or a multi-stage electro-hydraulic or electro-pneumatic injection system. For example, in common rail diesel applications, the valve may actuate a second hydraulic stage (e.g., nozzle) injector or pump.

Similar to the manner in which details of a human fingerprint may be analyzed to generate mathematical expressions that uniquely identify individual persons, electro-mechanical fluid system components (such as solenoid-operated fluid ejectors) may exhibit unique performance characteristics that may be analyzed to identify maps or "fingerprints" that may uniquely characterize their operation and dynamic behavior. The fingerprint of the injector may change over time through use due to, for example, aging or fouling. The fingerprints may be re-determined over time and compared to identify, characterize, and/or diagnose changes in actuator behavior. For example, a fuel injector may be fingerprinted when it is new and again after a period of use (e.g., a service interval), and the latter may be compared to the former to quickly and easily determine whether the operating behavior of the fuel injector has changed. Fingerprint information may also be used as an indicator of the cause of such a change in behavior, as a tool for determining whether an injector service (e.g., repair or replacement) is required, as a tool for predicting an estimated time until service will be required, as an input to an injector tuning or calibration process, or any other suitable process that may be performed based on fuel injector operating characteristics.

Generally, fluid injectors are energized with a set of actuation waveforms having different energy levels (e.g., a set of different currents or a set of different voltages). In this document, individual actuations based on a selected energy level are referred to as "shots" or "runs". The power consumption of the actuator is measured during each shot to identify a corresponding set of feedback waveforms. The set of feedback is analyzed to identify a number of predetermined subsets of data and/or features representative of a number of corresponding operating characteristics. Examples of such features and means to identify them will be discussed in more detail below. These features collectively outline selected operating characteristics of the actuator for use in further analysis or operation. For purposes of the description discussed in this document, the concepts of "data" and "collection of data" are synonymous.

FIG. 1 is a schematic diagram illustrating an example fluid (e.g., fuel) intake system 100 for a reciprocating engine. In some embodiments, the system 10 may be used to determine the response behavior of an injector (such as a solenoid operated fluid injector 20). An actuator controller 100, such as an Engine Control Module (ECM), is a hysteretic current or voltage controller for controlling actuation of the injector 20 and measuring injector behavior in response to being actuated in order to determine an injector fingerprint. By determining the injector fingerprint, the controller 100 may monitor, diagnose, and/or predict mechanical movement of an armature component (e.g., a valve) of the fluid injector 20.

the fluid injector 20 of the example fluid intake system 100 is a solenoid valve that includes a valve 22 (e.g., a needle valve) that is movable between a first configuration in which the valve 22 is in a mechanically "closed" position and a second configuration in which the valve 22 is in a mechanically "open" position. The valve 22 is driven by an actuator 24 (e.g., a solenoid) having a stator, a solenoid coil, a return spring, and an armature. At rest, the spring urges the valve 22 toward a "closed" position, thereby preventing pressurized fluid (e.g., fuel) from flowing from the fluid passage 35 (e.g., fuel gallery) to the fluid nozzle. When current is applied to actuator 24 from controller 100, fluid injector 20 operates to pull the armature with sufficient force to overcome the bias of the spring and move valve 22 toward the "open" position, allowing pressurized fluid to flow from fluid passage 35 to intake path 36 and on to intake valve 40 of combustion chamber 42.

the controller 100 provides a control signal (e.g., current) that energizes the solenoid coil, which in turn causes the injector 20 to open. The controller 100 also monitors control signals (e.g., current draw, back emf) to determine when and how the valve of the injector 20 moves during actuation. In general, by determining the operational behavior of the injector 20 under various actuation stimuli, the controller 100 may determine how it may reduce the current to the solenoid coil of the injector 20 (e.g., to save power) and/or determine the amount of time it takes for the valve 22 to move from the "closed" position to the "open" position (e.g., to calibrate valve timing, diagnose faults, predict faults).

according to one embodiment, the controller 100 may be used for the operations described herein. The controller 100 includes a processor 102, a memory 104, a storage device 106, and a switching controller 108. The processor 102 is capable of processing instructions for execution within the system 100. In one embodiment, processor 102 may be a Field Programmable Gate Array (FPGA) processor. For example, with the advent of very fast FPGAs, the switching controller 108 logic can be carefully observed and detect very small changes in the current and voltage waveforms at very fast clock rates.

in another implementation, the processor 102 may be a single-threaded processor. In another implementation, the processor 102 may be a multi-threaded processor. In some embodiments, processor 102 may be capable of processing instructions stored in memory 104 or on storage device 106 to gather information from fluid ejector 20 and provide control signals to fluid ejector 20.

The memory 104 stores information within the controller 100. In some implementations, the memory 104 may be a computer-readable medium. In some implementations, the memory 104 can be a volatile memory unit or units. In some implementations, the memory 104 can be a non-volatile memory unit.

the storage device 106 is capable of providing mass storage for the system 100. In one implementation, the storage device 106 is a computer-readable medium. In various different embodiments, storage 106 may be a non-volatile information storage unit (e.g., flash memory).

The switching controller 108 provides control signal output operations to the controller 100. The switching controller 108 provides an actuation control signal (e.g., a Pulse Width Modulation (PWM) driver signal) to the driver 30 that drives the actuator 24. For example, the switching controller 108 may include a Field Effect Transistor (FET) or other switching device that may convert a logic level signal from the processor 102 into a current and/or voltage waveform having sufficient power to drive the solenoid coil of the actuator 24. In another embodiment, the switching controller 108 receives feedback signals from the fluid injector 20, such as an impedance value (L, R), a rise time constant (L/R), and a counter-propagating electromagnetic force signal (e.g., back emf).

The features described herein may be implemented in digital electronic circuitry, or in computer hardware, firmware, software, or in combinations of them. Apparatus may be tangibly embodied in a computer program product for execution by a programmable processor in an information carrier (e.g., in a machine-readable storage device); and method steps can be performed by a programmable processor executing a program of instructions to perform functions of the described embodiments by operating on input data and generating output. The described features can be implemented advantageously in one or more computer programs that are executable on a programmable system including at least one programmable processor coupled to receive data and instructions from, and to transmit data and instructions to, a data storage system, at least one input device, and at least one output device. A computer program is a set of instructions that can be used, directly or indirectly, in a computer to perform a certain activity or bring about a certain result. A computer program can be written in any form of programming language, including compiled or interpreted languages, and it can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment.

suitable processors for the execution of a program of instructions include, by way of example, both general and special purpose microprocessors, and the sole processor or one of multiple processors of any kind of computer. Generally, a processor will receive instructions and data from a read-only memory or a random access memory or both. The essential elements of a computer are a processor for executing instructions and one or more memories for storing instructions and data. Generally, a computer will also include, or will be operatively coupled to communicate with, one or more mass storage devices for storing data files; such devices include magnetic disks (such as internal hard disks and removable disks); magneto-optical disks; and an optical disc. Storage devices suitable for tangibly embodying computer program instructions and data include all forms of non-volatile memory, including by way of example semiconductor memory devices, such as EPROM, EEPROM, and flash memory devices; magnetic disks, such as internal hard disks and removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks. The processor and memory may be supplemented by, or incorporated in, ASICs (application-specific integrated circuits).

In some embodiments, this detection, along with valve closing time data, may be used to calibrate and compensate for the timing of fluid injector 20 actuation to improve the accuracy and/or repeatability of fluid delivery. In some embodiments, determining injector dynamic operating characteristics may enable non-intrusive adaptive (e.g., dynamic) fluid reduction as the fluid injector 20 ages. In some embodiments, the operational characteristic detection may be used to reduce current in a later stage of a drive waveform used to actuate the fluid injector 20, which may be done in some applications to reduce power consumption, increase service life, and/or reduce cost of the fluid injector 20 and/or the controller 10.

FIG. 2 is a graph of an example current waveform 200 for an injector. In some embodiments, the current waveform 200 may represent the current observed when the example controller 100 of fig. 1 causes the valve 22 of the example fluid injector 20 to open.

in general, the controller 100 defines a current profile for actuation by subdividing substantially the entire current profile into a plurality of segments. In some embodiments, each segment may be configured with a set of parameters that define a control scheme for the FET bridge circuit. In some embodiments, each segment may be configured to analyze high-side and/or low-side comparator (HSC/LSC) switching. In some embodiments, signal filtering may be done in the FPGA to reduce noise associated with the FETs prior to performing segmentation.

current waveform 200 represents the current observed when the injector is actuated (e.g., when valve 20 of fluid injector 20 is open). The current waveform 200 includes a number of segments that represent various stages of actuation.

During the pull-in phase 210, the current is increased to increase the magnetic field strength acting on the armature (e.g., the valve 22). As the magnetic field strength increases, at some point the armature will begin to move from its valve seat (e.g., the "closed" position) and accelerate until it reaches its rest position (e.g., the "open" position).

During the hysteresis control phase 220, the current waveform 200 oscillates in response to the armature striking a hard stop (e.g., the valve 22 reaching an "open" position). During the hysteretic control phase 220, the current waveform 200 rises and falls. The rise and fall times of the coil current can be explained by the following formula:

。

Wherein:

L is the coil inductance (henry), which is a function of the coil current I (amperes) and the armature position x (meters).

v is the voltage (volts) supplied during this phase.

EMF_bIs the back electromotive force (volts).

r is the coil resistance (ohm).

The voltage may be a boosted voltage or a battery voltage, but typically 24V battery voltage is used for common rail applications. EMF_bRefers to the back emf generated during armature motion and which opposes the drive voltage during the pull-in phase. Once the armature strikes a hard stop (such as at an "open" position), EMF_bit suddenly drops to substantially zero and this can be detected by monitoring at the current and FET comparator waveforms. Under the hysteretic current control described herein, the FET comparator duty cycle is monitored to determine when the valve 22 has reached the "open" position. The time at which the valve 22 reaches the "open" position is known as the Valve Open Time (VOT).

The lag control phase 220 may be divided into two time intervals-before and after the valve 22 hits a stop at the "open" position. EMF before the valve 22 hits the stop_bIs very large and EMF once the valve 22 hits a stop_bit suddenly drops to substantially zero. According to the above formula, the current slew rate is dominated by EMF_band (5) controlling. The inductance (L), resistance (IR) and voltage (V) may be approximately constant. In this case, the Pulse Width Modulation (PWM) duty cycle of the switching controller 108 (e.g., FET comparator) may tend to flatten out after the valve 22 hits the stop. In use, hysteretic control actually has a fast (e.g., 10 microseconds) cycling rate, where there may be more partitions and interesting/useful current control shapes within T2. For example, the hysteresis control may be driven such that a detectable sharp minimum or a detectable high signal-to-noise ratio characteristic is produced at the first impact.

EMF is explained by the principle of faraday's law of electromagnetic induction, which is the generation of an electromotive force or voltage on an electrical conductor due to the dynamic interaction of the electrical conductor with a magnetic field. Lenz's law describes the direction of the induced field. The principles of lenz's law and faraday's electromagnetic induction law explain this and are given by the following equation:

。

the formula indicates that the induced voltage (epsilon) is opposite to the change in the magnetic flux (ϕ). Lenz's law explains the back electromotive force (BEMF) generated when the armature moves in a magnetic field. BEMF increases in proportion to the velocity of the armature, and becomes zero when the armature stops moving.

fig. 3 is a graph of an example set of current waveforms 300 for fluid injector 20. Each of the current waveforms 300 represents the current observed for a separate shot (e.g., run, actuation) when the example controller 100 of fig. 1 causes the valve 22 of the example fluid injector 20 to open in response to different actuation current levels. Although the examples discussed in this document generally describe current waveforms generated by various applied actuation currents (e.g., to drive solenoid-type actuators), in some embodiments, similar techniques may be used to characterize other types of actuators (e.g., piezoelectric actuators) based on a set of voltage waveforms generated by applying various drive voltages.

Fig. 4 and 5 are diagrams of an example pull trajectory 400. Fig. 4 shows a pull trace 400 superimposed on the set 300 of current waveforms, while fig. 5 shows only the pull trace (e.g., as a subcomponent of an actuator fingerprint).

in control and signal processing applications, noise, interference, and electromagnetic induction emissions and distortions are potential obstacles in signal pattern detection and diagnostics. Thus, estimation and cancellation of noise may be implemented to improve the signal-to-noise ratio required for an automatic fingerprinting process, such as the process described herein.

in this step of the process, the nominal noise level of the current waveform is estimated. In some embodiments, the best location to perform such detection is during the first few shots at the beginning and end of the process. In some embodiments, a predetermined number of samples may be evaluated to obtain a good statistical measurement. Noise spikes and ringing can be filtered to improve signal-to-noise ratio, while taking care that the actual signal artifact (e.g., armature bounce) is not affected by the filtering. In some implementations, if excessive noise is detected, the automatic process may be repeated, and if noise persists, a diagnostic alert may be sent to the user and the fingerprinting process may be terminated. In some embodiments, additional noise reduction steps may also be taken, such as shielding, grounding, and the like.

once an acceptable signal-to-noise ratio is found, it is then used to create thresholds and scales for the next steps. A sensation threshold is first calculated, which is the weakest signal that the process can detect as a true signal. The detection threshold level is a recognition threshold, which is a factor of typically 2 to 6 times the perception threshold. The process may determine the factor as a function of the estimated noise. The detection threshold may be used to quantify the ability to distinguish information-bearing patterns in the signal from random noise that may distort the information.

The pull trajectory 400 includes a set of start of injection (SOI) points 410. For each of the waveforms 300, the SOI point 410 (e.g., closing point, valve opening time VOT) coincides with the BEMF of the corresponding waveform 300 suddenly dropping to zero. In some embodiments, this behavior may be monitored by observing the minimum value of the current waveform during the hysteretic control phase 220 (e.g., T2, pull-hold period) or from the duty cycle of the switching controller 108.

Referring briefly to fig. 7 and 8, each injection shot is compared to its progressively adjacent shots. This is done by the following steps: each point in one of the waveforms 300, a current value of a point in the other waveform (e.g., typically a less adjacent waveform) that corresponds in time is identified to form a differential waveform 700. Fig. 7 and 8 show sets and subsets of such differential waveforms determined by the set of current waveforms 300.

Still referring to fig. 7 and 8, during the pull trajectory identification phase, a first injection shot in which there is a large current waveform change for shots progressively adjacent thereto is detected. In some embodiments, the minimum separation between two adjacent waveforms may be based on a signal-to-noise ratio. This first large change is shown by differential waveform 710.

Referring back to fig. 4, the larger current waveform 300 from which the differential waveform 710 is determined is identified as the minimum pull-in current waveform 402. The pull-in current for this shot corresponds to the following condition: the valve 22 moves and only barely reaches the rest position before returning to the valve seat (e.g., closed position). The SOI point corresponding to waveform 402 is identified as point 412. Point 412 represents the approximate minimum pull-in current required to experience any meaningful accumulation in the magnetic field to produce armature motion and thus fluid flow. Point 412 also represents the first (e.g., start) value of the pull trajectory 400.

As the current increases in subsequent shots, SOI occurs earlier because the stronger magnetic field is generated faster, thereby accelerating the valve 22 to the stop position more quickly. For each step of current increase as represented by waveform 300, a point 410 corresponding to the SOI of each waveform 300 is identified and stored. A trace of the SOI is created that is the pull trace 400 (e.g., pull current trace).

Increasing the pull-in current beyond a certain point does not accelerate the valve opening time and may contribute to joule or resistive heating. Heat released versus the square of the current I²Proportional to the coil resistance R. Further, in some examples, the opening may occur even before the pull-in current is achieved. Such a pull-in current is identified as the maximum pull-in current: i.e. beyond which the on-time is not affected. Referring to fig. 7 and 8, a differential waveform 700 exhibiting such behavior is identified as differential waveform 720. Referring back to fig. 4, the larger current waveform 300 (from which the differential waveform 720 is determined) is identified as the maximum pull-in current waveform 404. Referring to fig. 4 and 5, the SOI of the maximum pull-in current waveform 404 is identified as point 414. The point 414 also represents the last (e.g., end) value of the pull trajectory 400.

FIG. 6 is a graph of an example right margin 600 and an example right margin trajectory 610. Generally, increasing the pull-in current beyond a certain point does not accelerate the valve opening time and may contribute to joule or resistive heating. Similarly, maintaining the pull-in current for a longer time than is required to stabilize the armature at the rest position is unnecessary and can negatively impact coil and driver (e.g., ECU) life and power efficiency.

points contributing to the right margin trajectory 610 (e.g., pull-in hold current) are identified for each right margin point 612, and the right margin trajectory 610 is identified as representative of a valve opening stability criterion. The pull trajectory 400 and the right margin trajectory 610 represent the limits of optimal control of injector opening.

to provide a better conceptual example of how the right margin trajectory 610 is identified, we refer again to FIG. 8, which includes a right margin trajectory 850. As previously discussed, the differential waveform 710 is identified as being associated with the minimum pull-in current waveform 402 and the differential waveform 720 is identified as being associated with the maximum pull-in current waveform 404. To determine the right margin trajectory 750, a second pair of differential waveforms is identified.

the upper point 852 is identified by locating the differential waveform 820. Differential waveform 820 is identified as the next sequentially adjacent differential waveform after differential waveform 720. The peak of the differential waveform 820 is considered the upper point 852.

The lower point 854 is identified by locating the differential waveform 810. Differential waveform 810 is identified as the next sequentially adjacent differential waveform after differential waveform 710. The minimum value of the differential waveform 810 is considered as a lower point 854.

An interpolation is performed between the upper point 852 and the lower point 854, which interpolation is represented by a straight line in the illustration of the right margin trajectory 850. This line truncates a number of differential waveforms and each of these truncation points is considered to be an intermediate point 856. The set of middle points 856, upper points 852, and lower points 854 are considered in the differential domain as a right margin trajectory 850.

Referring to fig. 6, the right margin trajectory 850 is mapped back to the current/time domain as the right margin trajectory 610. The current/time coordinate of each intermediate point 856 is mapped onto the set of current waveforms 300 to identify the corresponding right margin point 612. The current/time coordinate of the upper point 852 is mapped onto the set of current waveforms 300 to identify a corresponding right margin point 614, and the current/time coordinate of the lower point 854 is mapped onto the set of current waveforms 300 to identify a corresponding right margin point 616 (e.g., a right margin anchor point). Together, right margin points 612, 614, and 616 define right margin trajectory 610. The current level associated with the right margin point 614 also represents a maximum pull-in current beyond which the actuator may not exhibit further actuation performance advantages, but beyond which the current may be allowed to temporarily increase.

right margin 600 is identified based on right margin point 616. However, in some implementations, right margin 600 may be determined based on other factors. For example, the right margin 600 may be a predetermined value based on a known value, such as a design parameter or right margin value that was previously empirically determined for a population of other similar (e.g., same make and model) fluid ejectors.

Referring again to FIG. 8, a process for identifying an example open track 870 will be discussed. Although the first opening cycle detects a first valve armature movement that results in a small change in current, the armature is not considered closed or valve opening has occurred until the armature has fully reached the stop position and stabilized without returning to the valve seat. This is often followed by a number of bounces, which then settle.

An injection shot that results in a substantially steady opening of the fluid injector is referred to as an opening pass or shot. During this firing, the armature is accelerating and suddenly stops at a stop position, and this stop produces a large change in BEMF that can be detected, according to lenz's law explained above.

In the example of fig. 8, the peak of the differential waveform 720 is identified as the upper opening point 872. To determine the lower opening point 874, the differential waveform 710 is analyzed to determine a zero-crossing point (e.g., where the differential value equals zero). Interpolation is performed between the upper opening point 872 and the lower opening point 874, as represented by the line of the opening trajectory 870. A plurality of intermediate differential waveforms in the set 700 are interpolated truncated and each of these truncated points is identified as an intermediate open point 876.

FIG. 9 is a graph illustrating an example waveform set 300 and an example open trace 910. The open trace 870 is mapped back to the current/time domain as the open trace 910. The current/time coordinate of each intermediate opening point 876 is mapped onto the set of current waveforms 300 to identify the corresponding opening point 912. The current/time coordinate of the upper opening point 872 is mapped onto the set of current waveforms 300 to identify the corresponding opening point 914 and the current/time coordinate of the lower opening point 874 is mapped onto the set of current waveforms 300 to identify the corresponding opening point 916. Together, the opening points 912, 914 and 916 define the opening trajectory 910.

As the pull-in current increases, several subsequent waveforms can be seen to intersect at a point (which will be referred to as the anchor point), which represents the ideal time for the valve to open. In the current example, the lower open point 916 is used to identify the anchor point. In some implementations, other techniques may be used to identify the anchor points. For example, the set of waveforms 300 may be analyzed directly to determine coordinates at locations where the waveforms 300 may intersect. The locations of these intersections may be mathematically combined to determine a centroid (e.g., an average or mean intersection), and the coordinates of the centroid may be identified as an anchor or anchor value.

FIG. 10 is a graph illustrating an example set of waveforms 300, an example pull trace 400, an example right margin 600, an example right margin trace 610, an example open trace 910, and an example current hold value 1010.

for a given electromagnetic actuator or fluid injector, a certain amount of power is required to initiate movement of the armature (e.g., valve needle), as represented by pull trace 400. For a given actuator or fluid injector, a certain amount of power is also required to fully open the armature, as represented by the opening trace 910. Similarly, for a given actuator or fluid injector, once the armature is fully open, a certain (e.g., generally less) minimum amount of power may be used in order to keep the armature fully open. This amount of power is referred to as the minimum holding current 1010.

In some embodiments, the coil current measured in amperes may represent the magnetic force (e.g., I |)_coil（A）×K_t(N/A (= force (N)). for example, information about force may provide a profound understanding of the motion of the armature and/or what holds the armature at a rest positionRate (e.g., in steady state, V)_coil（V）×I_coil(A) Power (W)). For example, information about power may be used to identify parameters for power supplies, driver circuits, coil design (e.g., temperature limits), and other suitable power-related parameters. In another example, the driver delivers power, but it is the force that moves the armature. If the valve is stuck, the actuator may still provide the same power, but the armature and valve may not move, and by determining both force and power, a stuck condition may be detected.

Referring back to fig. 8 again, the minimum holding current 1010 is determined from the set of differential waveforms 700. As discussed above, the minimum of the differential waveform 810 is considered the lower point 854. The lower point 854 is interpreted to also represent the time to reach the minimum holding current 1010. In the illustrated example, the lower point 854 occurs at approximately 1.38 ms.

Referring now to fig. 10, minimum pull-in current waveform 402 is analyzed to identify an amount of current flowing through an electromagnetic actuator of a fluid ejector at the time of lower point 854. The amount of current exhibited by the minimum pull-in current waveform 402 at the time of the lower point 854 is identified as the minimum hold current 1010. In the illustrated example, the lower point 854 occurs at approximately 1.38 ms, and the minimum pull-in current waveform 402 reaches 1.38 ms at the cutoff point 1012. In this example, the cutoff point 1012 occurs at a current level of approximately 3.5A. Thus, in the present example, the minimum holding current 1010 is identified as the determined 3.5A current level identified at the cutoff point 1012.

FIG. 11 is a graph illustrating an example fluid ejector fingerprint 1100. The injector fingerprint 1100 includes an example pull trajectory 400, an example right margin 600, an example right margin trajectory 610, an example open trajectory 910, and an example current hold value 1010. In the present example, the amount of data shown as the example waveform set 300 of fig. 3 collected for a particular fluid ejector may be reduced and summarized as a fluid ejector fingerprint 1100. Accordingly, the fluid ejector fingerprint 1100 may be stored and/or transmitted using a reduced amount of memory and/or data bandwidth as compared to storing and/or transmitting the waveform ensemble 300.

In some implementations, one or more additional fluid ejector fingerprints may be determined at a later time in a manner similar to the manner in which fluid ejector fingerprint 1100 is determined. Fluid ejector fingerprint 1100 may then be used as a baseline for comparison with these later fingerprints. Changes between various fingerprints of the same fluid ejector may indicate physical changes (e.g., mechanical wear, contaminant accumulation, electrical insulation breakdown, leakage) that the fluid ejector has undergone over time. In some embodiments, such changes may be analyzed to determine or predict when fluid injector components may need servicing or replacement.

FIG. 12 is a flow diagram of an example process 1200 for determining an electromechanical response of a fluid injector (e.g., for a fuel injector). In some implementations, the process 1200 may be performed by the example controller 100 of fig. 1.

At 1205, a set of data representative of a set of electrical waveforms is received, each waveform corresponding to a selected magnitude of electrical excitation provided to an actuator of the fluid ejector. For example, data representative of the example waveform set 300 of fig. 3 may be received by the controller 100.

At 1210, a pull trajectory is identified based on the data set. For example, the example pull trajectory 400 of FIG. 4 may be identified. In some embodiments, identifying the pull trajectory may include: selecting one or more subsets of the data set, each of the selected subsets representing a successive pair of the waveform set, each of the selected pairs representing electrical waveforms that are successive in terms of two amplitudes; for each of the selected third subsets: determining a differential waveform based on a difference between the pair of waveforms; determining that the differential waveform includes a zero crossing point; and identifying and adding a local maximum in time aspect of the second waveform in the selected pair to the other subset of data; and providing the other subset as a pull trajectory associated with the fluid ejector. For example, the waveform ensemble 700 may be analyzed to identify a set of waveforms to be included in the pull trajectory 400 based on a set of start of injection (SOI) points 410.

in some embodiments, the first local maximum in time may be an effect of the fluid injector solenoid armature beginning to move relative to a de-energized state of the fluid injector. For example, SOI point 410 may coincide with a sudden drop in BEMF corresponding to waveform 300 to zero.

At 1215, a detection threshold level value is determined based on the data set. In some implementations, determining the detection threshold level value may include estimating a nominal noise level of one or more of the set of electrical waveforms. For example, the example waveform set 300 and/or the example differential waveform set 700 may be analyzed to determine a signal-to-noise ratio, which may be used as a threshold to distinguish usable signals from sensor noise.

At 1220, a first subset of the set of data is identified based on the detection threshold level value and the set of data, the first subset representing a selected first electrical waveform of the set of electrical waveforms. For example, the example set of differential waveforms 700 of fig. 8 may be identified.

At 1225, a representative open value is identified based on the data set. For example, the example differential waveform 710 of FIG. 8 may be identified in association with the example minimum pull-in current waveform 402 of FIG. 4.

At 1230, a representative close value is identified based on the representative open value and the data set. For example, the example differential waveform 720 of fig. 8 may be identified in association with the example maximum pull-in current waveform 404 of fig. 4.

At 1235, an anchor value is identified based on the set of data and the first subset. For example, lower opening point 916 may be used to identify an anchor value (e.g., anchor point). In some embodiments, identifying the anchor value may include: selecting one or more third subsets of the data set, each of the selected subsets representing a successive pair of the waveform set, each of the selected pairs representing electrical waveforms that are successive in terms of two amplitudes; and for each of the selected third subsets: determining a differential waveform based on a difference between the pair of waveforms; determining that the differential waveform is a first differential waveform that will include a zero crossing point; and providing the zero crossing point as an anchor value associated with the fluid ejector. For example, analysis may be performed in the set of differential waveforms 700 to identify a lower open point 874, which is located at a zero crossing point of the differential waveform 710.

At 1240, a second subset of the set of data is identified. Based on the data set, the pull trajectory, the first subset, and the representative open value, the second subset represents a selected second electrical waveform of the set of electrical waveforms. For example, the example right margin trace 610 of fig. 6 may be identified as a boundary beyond which increasing the pull-in current may not accelerate the valve opening time and may contribute to joule or resistive heating.

in some implementations, identifying the second subset of the set of data can include: identifying a final value of a pull trajectory; identifying a subset of the data set corresponding to the last value; the identified subset is provided as a second subset. For example, the right margin trajectory 610 may be identified by identifying a right margin point 614 (e.g., a first value of the right margin trajectory 610), a right margin point 612 (e.g., a middle value of the right margin trajectory 610), and a right margin trajectory 616 (e.g., a last value of the right margin trajectory 610).

at 1245, a maximum electrical value is identified based on the second subset. For example, the current level associated with the right margin point 614 may represent a maximum pull-in current above which the fluid injector may not exhibit further actuation performance advantages.

At 1250, an open trajectory is identified based on the data set, the anchor value, and the maximum electrical value. For example, the example open trajectory 870 of fig. 8 may be identified based on the open point 912 and the open point 914 of fig. 9, which is based on the waveform collection 300.

In some embodiments, identifying an opening trajectory may include: selecting one or more third subsets of the data sets, each of the selected subsets representing a successive pair of the waveform sets, each of the selected pairs representing electrical waveforms of the fluid injector successive in two amplitudes; and for each of the selected third subsets: determining a differential waveform based on a difference between the pair of waveforms; adding the determined differential waveform to a set of differential waveform data; identifying an anchor point within the set of differential waveform data; identifying a maximum electrical value within the set of differential waveform data; determining a mathematical expression of a line between an anchor value and a maximum electrical value within the differential waveform data set; identifying a set of values within the set of differential values that intersect the mathematical expression; and providing the identified set of values as an opening trajectory associated with the fluid ejector. For example, the set of differential waveforms 700 may be analyzed to identify the peak of the differential waveform 720 as the upper opening point 872, identify the zero crossing point of the differential waveform 710 to determine the lower opening point 874, and an interpolation may be performed between the upper opening point 872 and the lower opening point 874 as represented by the line of the opening trace 870, and a truncation of the interpolation may identify the middle opening point 876. The opening points 872, 874, and 876 can be mapped back to the waveform ensemble 300 to identify the corresponding opening points 912, 914, and 916 and define the opening trajectory 910.

at 1255, a retention value is identified based on the data set. In some embodiments, identifying the retention value may include: identifying a first stabilizing waveform for the fluid ejector, the first stabilizing waveform comprising values described by the pull trajectory and satisfying one or more stabilization criteria; determining a minimum electrical value based on the first stabilizing waveform; and providing the minimum electrical value as a hold value associated with the fluid ejector. For example, the example minimum holding current 1010 of fig. 10 may be identified based on the example lower point 854.

At 1260, the pull trace, the open trace, the hold value, the anchor value, and the representative close value are provided as a characteristic associated with the fluid ejector (e.g., a fluid ejector fingerprint). For example, the pull trace 400, the open trace 910, the minimum hold current 1010, and the anchor value as represented by the lower open point 916 are provided as the example fluid ejector fingerprint 1100 of fig. 11.

In some implementations, the set of fluid injector electrical waveforms may be a current waveform of the fluid injector, the set of data may be a first set of fluid injector current measurements representative of the current waveform, the pull trajectory may be a second set of fluid injector current measurements, the representative opening value may be the first fluid injector current measurement, the anchor value may be the second fluid injector current measurement, the maximum electrical value may be a third fluid injector current measurement, and the opening trajectory may be a third set of fluid injector current measurements. For example, the example waveform set 300 is a current waveform set, and the pull-in trace 400, the open trace 910, the minimum hold current 1010, and the anchor value as represented by the lower open point 916 are all based on current measurements. However, in some embodiments, voltage measurements may be used (e.g., for a fingerprint recognition type piezoelectric fluid actuator).

In some embodiments, the process may include: a solenoid of the fluid injector is actuated with a solenoid actuation waveform based on a representative opening value associated with the fluid injector. For example, a solenoid-based fluid ejector may be analyzed to determine a fluid ejector fingerprint (such as fluid ejector fingerprint 1100). Some or all of the data represented by fluid injector fingerprint 1100 (e.g., opening trace 910) may be used to define an electrical waveform (e.g., current waveform) that may be used to actuate a fluid injector solenoid in a variety of ways that may be unique to the performance characteristics of that particular fluid injector (e.g., by providing only the minimum amount of power required to cause actuation, by providing at least the minimum amount of power required to keep the injector open).

The example system 10 and/or the example process 1200 may be used to identify a fluid ejector fingerprint, such as the example fluid ejector fingerprint 1100. The example fluid ejector fingerprint 1100 includes sufficient information to determine a set of fluid ejector characteristics. For example, based on fluid ejector fingerprint 1100, a user may calculate electromechanical hydraulic characteristics for a particular fluid ejector, including: coil self-inductance, coil resistance, back-emf, electrical delay or dead time from signaling to the start of armature motion, armature inertia, effective spring constant of the armature spring-mass assembly, spring pre-tension, estimated static friction force, estimated damping coefficient, estimated armature impact velocity, estimated residual or coercive force, a plot of estimated electromagnetic force versus coil current and armature position, nominal valve opening and closing time, nominal bounce during opening and closing, fuel reduction limit. In some embodiments, the user input and the measured characteristics described above may be used to determine limits or thresholds for indicating diagnostic data, such as coil overheating, ECU voltage low, coil or battery or ground short, open circuit, poor wiring, valve sticking (e.g., injector dirty, misfire, poor engine performance, emissions), spring failure, large air gap, magnetic saturation, increased bounce, poor shot to shot repeatability, valve opening or closing delay, engine misfire, open valve sticking or debris (e.g., causing engine knock), closed valve sticking or debris or insufficient fuel pressure (e.g., causing engine misfire), large electrical delay or dead time (e.g., causing ignition delay and/or poor combustion), and large impact velocity (e.g., causing armature wear).

while the examples in this document are generally described in the context of solenoid operated fluid injectors, other embodiments and implementations exist. For example, the systems and techniques described herein may also be applied to other forms of fluid control employing electromagnetic actuators, such as solenoids, servomotors, stepper motors, linear motors, or combinations of these and any other suitable forms of actuators (e.g., fuel injectors). In another example, the systems and techniques described herein may also be applied to any suitable form of apparatus for controlling the ingress of combustible fluids (e.g., gasoline, diesel), non-combustible fluids (e.g., water), combustible gases (e.g., natural gas, hydrogen), non-combustible gases (e.g., oxygen, nitrogen, carbon dioxide), or vapors (e.g., water vapor).

in some implementations, the fluid ejector fingerprint may describe only the actuator. For example, a coil or solenoid (e.g., coil and armature together) may be fingerprinted outside of the system that was or will be used (e.g., bench test, no valve, no fluid). In some implementations, the fluid ejector fingerprint may describe the actuator in combination with one or more elements of an environment in which the actuator is used. For example, the fingerprint is unique to a given combination of actuators, valves, fluid parameters (e.g., density, viscosity, lubricity), fluid inlet parameters (e.g., flow, pressure, volume), fluid outlet parameters (e.g., flow, pressure, volume), temperature, or a combination of these with another suitable parameter of the fluid ejection system.

although some embodiments have been described in detail above, other modifications are possible. For example, the logic flows depicted in the figures do not require the particular order shown, or sequential order, to achieve desirable results. In addition, other steps may be provided, or steps may be eliminated, from the described flows, and other components may be added to, or removed from, the described systems. Accordingly, other implementations are within the scope of the following claims.