WO2017190931A1

WO2017190931A1 - Identifying fuel injectors with similar movement behavior

Info

Publication number: WO2017190931A1
Application number: PCT/EP2017/058841
Authority: WO
Inventors: Ulrich Wagner; Frank Hacker
Original assignee: Continental Automotive Gmbh
Priority date: 2016-05-03
Filing date: 2017-04-12
Publication date: 2017-11-09
Also published as: DE102016207629B3

Abstract

The invention relates to a method for identifying fuel injectors with a similar movement behavior. The fuel injectors have a solenoid drive with a movable armature. The method has the following steps: (a) carrying out a first series of actuations of a first fuel injector, each actuation of the first series of actuations being carried out with an actuation time which increases incrementally after each individual actuation, (b) detecting a first series a closing times of the first fuel injector, each individual closing time of the first series of closing times corresponding to an actuation time of the first series of actuations, (c) carrying out a second series of actuations of a second fuel injector, each actuation of the second series of actuations being carried out with an actuation time which increases incrementally after each individual actuation, (d) detecting a second series of closing times of the first fuel injector, each individual closing time of the second series of closing times corresponding to an actuation time of the second series of actuations, (e) comparing a relationship between the closing time and the actuation time for the first fuel injector with a relationship between the closing time and the actuation time for the second fuel injector, and (f) determining whether the movement behavior of the first fuel injector is similar to the movement behavior of the second fuel injector based on the comparison. The invention also relates to a motor controller and a computer program.

Description

description

Identification of fuel injectors with similar motion behavior

The present invention relates to the technical field of controlling fuel injectors, in particular fuel injectors for an internal combustion engine of a motor vehicle. In particular, the present invention relates to a method for identifying fuel injectors with similar motion behavior, the fuel injectors having a solenoid drive with a movable armature. The present invention also relates to a method of driving a plurality of fuel injectors having a solenoid drive with a movable armature, a motor controller, and a computer program.

When operating directly operated Kraftstoffinj injectors with solenoid drive (also called Spuleneinspritzinj) with the same current / voltage parameters, it comes due to electrical, magnetic and mechanical tolerances to different temporal opening behavior (OPP1) and closing behavior (OPP4) of the individual injectors and thus to variations in the respective injection quantity.

For operation, the injectors are subjected to a specific voltage or current profile over time, which usually has a boost phase, a first holding phase and a second (the actual) holding phase in relation to the opening process. The closing process begins at the end of the second holding phase, by the corresponding holding current is turned off.

The relative injection quantity differences from injector to injector increase with shorter injection times. So far, these relative differences in quantity were small and without practical significance. The trend towards smaller injection quantities and times, however, means that the influence of the relative quantity differences is no longer out of the question can be left. Variation when closing (OPP4) or stopping the movement of an injector has so far been compensated by a suitable closing time detection. A variation in the opening (OPP1) could until now only be compensated by narrow mechanical component tolerances.

The present invention has for its object to be able to compensate for variations in opening times in a simple manner, in particular without additional hardware.

This object is solved by the subject matters of the independent claims. Advantageous embodiments of the vorlie ^¬ constricting invention are described in the dependent claims. According to a first aspect of the invention, a method is described for identifying fuel injectors with similar motion behavior, the fuel injectors having a solenoid drive with a movable armature. The described method comprises: (a) performing a first series of drives of a first fuel injector, wherein each drive of the first series of drives is performed with a drive time which is incrementally increased after each individual drive, (b) detecting a first one Series of closing times of the first fuel injector, wherein each individual closing time of the first series of closing times corresponds to a driving time of the first series of actuators, (c) performing a second series of actuations of a second fuel injector, each driving of the second series of actuators having one Activation time is performed, which is gradually increased after each control ^{¬ on} , (d) detecting a second series of closing times of the first fuel injector, each individual closing time of the second series of closing times of a driving time of the second series of controls speaks, (e) comparing a relationship between

Closing time and activation time for the first fuel injector with a relationship between closing time and activation time for the second fuel injector and (f) determining whether movement behavior of the first fuel injector is similar to the movement behavior of the second fuel injector based on the comparison. The described method is based on the finding that fuel injectors with similar movement behavior, ie in particular similar or comparable mechanical properties, can be identified by comparing the relationships between drive time and closing time for each fuel injector. In Kraftstoffinj injectors with similar motion behavior in this sense, then a difference in the detected closing times can be used to adjust the beginning of the control of one or more of the fuel injectors, since the aforementioned difference between closing times will occur even at the opening times. In other words, the opening times can be aligned indirectly based on the closing times.

In this document, "driving time" in particular the period during which the solenoid drive with

electrical energy is supplied. In general, the on ^¬ control time begins with the switching on a relation to the vehicle electrical system voltage boost voltage and ends with the switching off of the boost voltage (in ballistic operation) or with the off a following after the boost voltage holding voltage (in linear operation).

In this document, "closing time" refers, in particular, to the time from the end of the actuation (or actuation time) to the end of the closing process of the fuel injector Generally, the closing process ends at the time when both the nozzle needle and the armature are in the starting position again. This event can be detected by various known methods, for example by analyzing the time course of the coil voltage, both the end of the nozzle needle movement and the end of the armature movement can be detected with the just mentioned methods known as such Idle stroke, a "closing time" can be detected even then when the driving time is so short that only the anchor is moved (ie follows a ballistic trajectory) without the Dü ^¬ nozzle needle contact. According to the invention force ^¬ stoffinj ector is a number of activations / measurements performed for each (first and second). More specifically, each fuel injector is operated with a series of stepwise increasing drive times and the corresponding close times are detected to provide the relationship between drive time and closing time for the individual fuel injector or stored in a data memory as a series of related drive times and closing times , The individual connections between drive time and closing time are compared, and based on this comparison, the similarity of the Be ^¬ wegungsverhaltens the individual Kraftstoffinj is determined reflectors.

In this document, "similar motion behavior" is understood to mean that the movement of the mechanical system (in particular of the armature) of a first fuel injector at similar or identical values of control parameters (for example magnitude and length of the boost voltage pulse) with the movement of the mechanical system of a second fuel injector similar to or substantially the same. for example, comprise two fuel injectors, a similar movement behavior when the parabolic trajectories of the armature are of equal width and equal in ballistic operating substantially. According includes an embodiment of the invention driving the Ver ^¬ further comprising: (a) determining a first minimum drive time for the first fuel injector at which movement of the armature of the first fuel injector occurs, and (b) determining a second minimum drive time for the second fuel injector at which a movement of the armature of the second fuel injector takes place, the same Ver ^¬ the relationship between time and closing actuation time for the first fuel injector with the relationship between Closing time and driving time for the second fuel injector injector has a comparison of the first minimum drive time and the second minimum drive time. In other words, the lowest or minimum drive time at which an armature movement can be detected is determined for each fuel injector.

According to a further embodiment of the invention, comparing the relationship between closing time and An ^¬ control time for the first Kraftstoffinj ector with the relationship between closing time and driving time for the second fuel injector if the first minimum drive time is substantially equal to the second minimum drive time, further a comparison of the relationship between closing time and driving time for the first fuel injector from the first minimum drive time on the connection between the closing time and the driving time for the second fuel injector from the second minimum driving time on.

In other words, in the case where the first minimum drive time is substantially equal to the second minimum drive time, the relationships between closing time and drive time are compared only from the substantially common minimum drive time. Thus, only the actual movements of the fuel injectors are compared.

According to a further embodiment of the invention, the relationship between closing time and driving time for the first fuel injector and the relationship between

Closing time and driving time for the second Kraftstoffinj ector stored as interpolation curves.

The drive time and the detected closing time pairs are stored as points connected by curve segments to form the interpolation curves. These curves can be easily compared by using mathematical and / or numerical methods. According to a further embodiment of the invention, the first fuel injector is in ballistic operation in the first series of actuations and the second fuel injector is in ballistic operation in the second series of actuators.

In the ballistic operation, the armature and optionally the nozzle needle follow a parabolic trajectory, the fuel injector never being fully opened.

According to a second aspect of the invention, a method is described for driving a plurality of fuel injectors each having a magnetic coil drive with a movable armature. The described method comprises: (a) identifying a group of fuel injectors having similar motion behavior by performing a method according to the first aspect or one of the above embodiments; (b) driving each fuel injector in the group according to predetermined respective start times and drive times , (c) detecting the closing times for each controlled fuel injector in the group and (d) if a closing time deviates from a predetermined closing time, correcting the corresponding starting time.

The method according to this second aspect of the invention is the recognition that a deviation between the actual and predetermined closing time for one or more force ^¬ stoffinj reflectors in a group which have supply conduct a similar movement is compensated by a corresponding correction of the start time of the control can be. Thus, a late or premature start of opening of the

Fuel injector are compensated in a simple manner based on a detected deviation of the closing time indirectly.

In accordance with a third aspect of the invention, an engine control system for a vehicle is disclosed that employs a method is arranged according to the first and / or second aspect and / or one of the above embodiments.

This engine control makes it possible to easily implement the advantages described above in connection with the first aspect and the second aspect directly in a vehicle.

According to a fourth aspect of the invention, a computer program is described which, when executed by a processor, is adapted to perform the method according to the first and / or second aspect and / or one of the above embodiments.

For the purposes of this document is the mention of such Com ^¬ computer program equivalent to the concept of a Pro ^¬ program element, a computer program product and / or a computer-readable medium containing instructions for controlling a computer system to the operation of a system or a method in to coordinate suitably to achieve the effects associated with the method according to the invention.

The computer program may be implemented as a computer-readable instruction code in any suitable programming language such as JAVA, C ++, etc. The computer program can be stored on a computer-readable storage medium (CD-ROM, DVD, Blu-ray Disc, removable drive, volatile or non-volatile memory, built-in memory / processor, etc.). The instruction code may program a computer or other programmable device such as, in particular, an engine control unit of a motor vehicle to perform the desired functions. Further, the computer program may be provided in a network, such as the Internet, from where it may be downloaded by a user as needed.

The invention can be achieved both by means of a computer program, ie software, and by means of one or more special ones electrical circuits, ie in hardware or in any hybrid form, ie by means of software components and hardware components realized. It should be noted that embodiments of the invention have been described with reference to different subject ^{matters ¬} . In particular, some embodiments of the invention are described with method claims and other embodiments of the invention with apparatus claims. However, it will be readily apparent to those skilled in the art upon reading this application that, unless explicitly stated otherwise, in addition to a combination of features belonging to a type of subject matter, any combination of features that may result in different types of features is also possible Subject matters belong.

Further advantages and features of the present invention will become apparent from the following exemplary description of a preferred embodiment.

Figure 1 shows a representation of similar and not

similar movement behavior in the context of the present invention.

FIG. 2 shows a representation of relationships between

Actuation time and closing time for several power ^¬ stoffinj reflectors according to an embodiment of the present invention.

It should be noted that the embodiments described below represent only a limited selection of possible embodiments of the invention. FIG. 1 shows a representation of similar and not similar movement behavior in the sense of the present invention. More specifically, the left half of Figure 1 shows a first movement curve 11 for a first fuel injector and a second movement curve 12 for a second fuel ^¬ injector, wherein the movement curves represent the anchor position x as a function of time t. Both fuel injectors are in ballistic mode, that is, the movement curves 11 and 12 are parabolic. The right half of FIG. 1 shows a third movement curve 15 for a third fuel injector and a fourth movement curve 16 for a fourth fuel injector. The four fuel injectors are controlled the same, that is, with the same amount of on-time.

As can be seen, the first parabolic movement curve 11 for the first fuel injector is both significantly higher and significantly wider than the second parabolic movement curve 12. In other words, the armature of the first fuel injector is moved further away from its rest position than the armature of the second fuel injector ector and the movement of the armature of the first fuel injector also takes longer than the movement of the armature of the second fuel injector. These different movements now also lead to the time difference 13 between the start of the respective armature movements (OPP1) being greater than the time difference 14 between the end of the respective armature movements (OPP4). On the other hand, the third parabolic BEWE ^¬ supply curve 15 is for the third fuel injector of the fourth parabolic motion curve for the fourth Kraftstoffin- jector very similar, both as regards the height and the width of the parabola. In other words, the anchor of the third Kraftstoffinj will ector moved equally far away from its rest position ^¬ as the anchor of the fourth fuel injector and the movements of the two anchor takes about the same length. In this case, the time difference 17 between the beginning of the respective armature movements (OPP1) is essentially equal to the time difference 18 between the end of the respective armature movements (OPP4). Thus, a detected difference 18 between the closing times (OPP4) can be transferred directly to the opening time (OPP1), in the sense that a time shift the movement curve 16 to the left, so that the closing times (OPP4) are aligned, will also lead to the same time that the opening times (OPP1) are aligned. In summary, in the context of the present invention, the movement behavior of the first fuel injector is not similar to the movement behavior of the second fuel injector, the movement behavior of the third fuel injector being similar to the movement behavior of the fourth fuel injector.

2 shows a diagram of connections between drive time TA and closing time TS for a plurality of (four) power ^¬ stoffinj reflectors according to an embodiment of the vorlie ^¬ constricting invention. A series of measurements is carried out for each of the four fuel injectors, wherein the electrical drive time TA starts at 100 ys and is increased by a step length of 10 ys to TA = 300 ys. For each actuation time TA, the corresponding closing time TS is detected by means of a method known as such. The closing time TS here denotes the period of time from the end of the electrical activation to the detection of a closing event by means of the known method.

As can be seen in FIG. 2, the interpolation curves essentially run in three sections, which are marked as A, B and C in FIG. In section A, the closing time TS increases substantially linearly with increasing activation time. Here are the courses for the individual

Fuel injectors almost equal, but two curves 21 and 22 can be detected. In section B, these curves separate into four individually identifiable curves 23, 24, 25 and 26. The curves 23 and 24 at TA = 200 ys make a clear jump upwards, with the curves 25 and 26 following similar jumps a little later make up. These jumps mark that an actual movement of the respective anchor now takes place. The linearly increasing closing time TS as a function of the actuation time TA in section A is due to the implementation of the algorithm for detecting the closing time used here, the values due to robustness requirements for the closing time, although no actual movement has taken place. In section C, the curve 24 clearly separates from the curves 23, 25 and 26. Since all the curves in section B leave their linear course, it can be deduced from this that all injectors perform a movement with the beginning of section C. If a suitable step size of TA is adhered to, all injectors perform a ballistic movement with the beginning of section C. Thus, in the initial region of the section C, a carry-over from "closing time" to an "opening time" can be made since the injectors are safely located there at a ballistic operating point. Section C is, as it were, the transitional range from a ballistic mode of the armature to a linear mode. The transfer of the closing time difference of curve 24 to the opening time is thus in the initial range of section C to ^¬ casual.

The measurement series shown in FIG. 2 can preferably be performed directly by a suitably arranged engine control unit. Thus, the engine control unit can

Group fuel injectors in a motor vehicle and use this grouping to adjust the timings of the individual controls. As a result, the intended injection quantities can be obtained at the scheduled timings.

Reference sign list

11 movement curve

12 movement curve

13 time difference

14 time difference

15 movement curve

16 movement curve

17 time difference

18 time difference

X anchor position t time

21 interpolation curve

22 interpolation curve

23 interpolation curve

24 interpolation curve

25 interpolation curve

26 interpolation curve

TA activation time

TS closing time

A section

B section

C section

Claims

claims

A method of identifying fuel injectors with similar motion behavior, wherein the fuel injectors comprise a solenoid drive having a movable armature, comprising the method

Performing a first series of activations of a first fuel injector, wherein each actuation of the first series of actuators is performed with a drive time that is incrementally increased after each individual actuation,

Detecting a first series of closing times of the first fuel injector, each individual closing time of the first series of closing times corresponding to a driving time of the first series of actuators,

Carrying out a second series of activations of a second fuel injector, wherein each actuation of the second series of actuations is carried out with a drive time which is increased stepwise after each individual actuation,

Detecting a second series of closing times of the first fuel injector, each individual closing time of the second series of closing times corresponding to a driving time of the second series of actuators,

Comparing a relationship between the closing time and the driving time for the first fuel injector with a relationship between the closing time and the driving time for the second fuel injector and

Determining whether the movement behavior of the first fuel injector is similar to the movement behavior of the second fuel injector

Fuel injector is based on comparing.

2. A method according to the preceding claim, further comprising

Determining a first minimum drive time for the first fuel injector at which movement of the armature of the first fuel injector takes place, and Determining a second minimum drive time for the second fuel injector, at which a movement of the armature of the second fuel injector takes place,

- Wherein comparing the relationship between closing time and driving time for the first fuel injector with the

Connection between closing time and driving time for the second fuel injector has a comparing the first minimum driving time and the second minimum driving time.

3. The method of claim 1, wherein when the first minimum drive time is substantially equal to the second minimum drive time, comparing the relationship between closing time and drive time for the first fuel injector with the relationship between closing time and drive time for the second fuel injector further Having a comparison of the relationship between closing time and An ^¬ control time for the first Kraftstoffinj ector from the first minimum drive time with the relationship between closing time and driving time for the second Kraftstoffinj ector from the second minimum driving time has.

4. The method according to any one of the preceding claims, wherein the relationship between closing time and driving time for the first fuel injector and the relationship between

Closing time and driving time for the second fuel injector are stored as interpolation curves.

5. The method according to any one of the preceding claims, wherein the first fuel injector in the first row of

Controls is in ballistic mode and wherein the second fuel injector is in the second series of Ansteuern in ballistic mode.

6. A method for driving a plurality of fuel injectors having a solenoid drive with a movable armature, comprising the method Identifying a group of fuel injectors with similar movement behavior by carrying out a method according to one of the preceding claims,

Driving each fuel injector in the group according to predetermined respective start times and drive times,

Detecting the closing times for each controlled fuel injector in the group and

- if a closing time deviates from a given closing time, correcting the corresponding start time.

7. A motor controller for a vehicle that is configured to use a method according to one of the preceding claims.

A computer program which, when executed by a processor, is arranged to perform the method of any one of claims 1 to 6.