WO2010133417A1

WO2010133417A1 - Method and control device for the operation of an injection valve

Info

Publication number: WO2010133417A1
Application number: PCT/EP2010/055358
Authority: WO
Inventors: Klaus Joos; Ruben Schlueter; Jens Neuberg; Helerson Kemmer; Hans-Peter Lehr; Holger Rapp; Haris Hamedovic; Joerg Koenig; Anh-Tuan Hoang; Bernd Wichert
Original assignee: Robert Bosch Gmbh
Priority date: 2009-05-19
Filing date: 2010-04-22
Publication date: 2010-11-25
Also published as: DE102009003212A1

Abstract

The invention relates to a method for operating an injection valve (100a), especially in an internal combustion engine (10) of a motor vehicle, in which a component of the injection valve (100a), in particular a valve needle (116), is driven using an electromagnetic actuator (102, 104), and in which the actuator (102, 104) is controlled using a control signal (I) that has a control period (ti) in order to inject an amount of fuel which depends on the control period (ti). According to the invention, the control period (ti) is corrected in accordance with an individual corrective value (tkorr) for the injection valve (100a) in order to obtain a corrected control period (ti_korr).

Description

description

title

Method and control device for operating an injection valve

State of the art

The invention relates to a method for operating an injection valve, in particular an internal combustion engine of a motor vehicle, in which a component of the injection valve, in particular a valve needle, is driven by means of an electromagnetic actuator, and in which the actuator is driven by a control signal having a drive time to a Inject injection quantity dependent on the actuation duration.

The invention further relates to a control device for operating such an injection valve and a computer program for a computing unit of

Controller.

The conventional methods and systems of the aforementioned type are based on the pilot control principle, according to which the activation duration for all injectors is determined in the same way from an amount of fuel to be injected, which is predetermined by a control of the internal combustion engine.

Disclosure of the invention

It is an object of the present invention, an operating method and a

Control unit of the type mentioned above to improve that a more precise injection is possible.

This object is achieved according to the invention in the operating method of the type mentioned in that the driving time in dependence of a for the injector individual correction value is corrected to obtain a corrected drive duration.

The provision according to the invention of a valve-individual correction value for the actuation duration advantageously provides the possibility of particular

Characteristics of the respective injection valve to take into account during the control, which in particular also copy variations of different injection valves of an internal combustion engine can be compensated. In particular, the closing duration of an injection valve operated according to the invention can thereby be advantageously influenced.

In particular, according to the invention is advantageously given the opportunity to equalize several injection valves of an internal combustion engine in terms of the amount of fuel injected by them, whereby the emission behavior of the internal combustion engine improves. This can be realized according to the invention, for example, by the provision of a corresponding correction value which, for each injection valve, takes into account its individual properties or specimen scatters, i. Deviations from a reference valve, is determined.

In a particularly advantageous variant of the invention, it is provided that the actuation period is regulated to a predefinable setpoint value, which-in contrast to a pure control using a static correction value for the actuation duration-achieves a further increase in the precision of the injection. In this variant of the invention, the valve-individual correction value according to the invention is advantageously cyclically re-formed within the scope of a control process and used to regulate the actuation duration of an injection valve to a predetermined desired value.

In this way, both valve-individual long-term drift effects of the injection quantity can be compensated for as well as short-term changes, for example, from variable boundary conditions such as temperature, fuel properties, return back pressure, Ventilstückdurchbiegung and the like. In a further particularly preferred variant of the invention, it is provided that the desired value for the actuation period is determined as a function of a predefinable closing duration, so that according to the invention a control of the operation of the injection valve to achieve the predefinable closing duration is performed.

In particular, in the application of the operating method according to the invention for the operation of fuel injection valves of an internal combustion engine, according to the invention can also be advantageously provided that the desired value for the control duration in response to averaged over a plurality of injectors

Closing time is determined, which advantageously equality of the plurality of injectors is achieved with respect to the amount of fuel injected by them.

In a further advantageous variant of the invention, the closing duration is advantageously determined dynamically from operating variables of the injection valve, for example by analyzing electrical control variables of an electromagnetic actuator of the injection valve or else using separate sensors.

The operating method according to the invention is particularly suitable for use in a Vollhubbereich of the injection valve in which a fuel injection controlling component of the injection valve, such as a valve needle, so far removed from its closed position during its opening movement that it reaches a stroke limiting their needle stroke.

As a further solution of the object of the present invention, a control device according to claim 7 is given.

Of particular importance is the realization of the operating method according to the invention in the form of a computer program which can be stored on an electronic or optical storage medium and which can be executed by a control and / or regulating device, for example for an internal combustion engine. Further advantages, features and details will become apparent from the following description in which, with reference to the drawings, various embodiments of the invention are shown. The features mentioned in the claims and in the description may each be essential to the invention individually or in any desired combination.

In the drawing shows:

1 shows a schematic representation of an internal combustion engine with a plurality of injection valves operated according to the invention, FIG.

FIGS. 2a to 2c schematically show a detailed view of an injection valve from FIG. 1 in various operating states,

3 shows a time profile of operating variables of the injection valve from FIG. 1, and FIG

FIG. 4 shows a simplified functional diagram of an embodiment of the method according to the invention.

In FIG. 1, an internal combustion engine bears the reference numeral 10 as a whole. It comprises a tank 12, from which a delivery system 14 delivers fuel into a common rail 16. To this, a plurality of electromagnetically operated injection valves 100a to 100d are connected, which inject the fuel directly into them associated combustion chambers 20a to 2Od. The operation of the internal combustion engine 10 is controlled or regulated by a control and regulating device 22 which, among other things, also controls the injection valves 100a to 100d.

FIGS. 2 a to 2 c show an embodiment of the fuel injection injection valve 100 a of the internal combustion engine 10 according to FIG. 1 in various operating states of an injection cycle. The further injection valves 100b, 100c, 100d have the same structure and function. FIG. 2a shows the injection valve 10Oa in its idle state, in which it is not actuated by the control device 22 assigned to it. A solenoid valve spring 1 1 1 presses here a valve ball 105 in a seat provided for this purpose, the flow restrictor 1 12, so that in the valve control chamber 106 a rail pressure corresponding fuel pressure can build up, as it also prevails in the region of the high pressure port 1 13.

The rail pressure is also present in the chamber volume 109, which surrounds the valve needle 16 of the injection valve 100a. The applied by the rail pressure on the end face of the control piston 1 15 forces and the force of the nozzle spring 107 hold the valve needle 1 16 against an opening force which engages the pressure shoulder 108 of the valve needle 16 1 closed.

FIG. 2b shows the injection valve 100a in its open state, which, under the control of the control unit 22, it assumes in the following manner from the idle state depicted in FIG. 2a: the magnetic coil 102 shown here in FIG. 2a and the solenoid 102 cooperating with it Magnetic armature 104 formed electromagnetic actuator 102, 104 is acted upon by the control unit 22 with a drive signal forming a drive current I to cause opening of the present acting as a control valve solenoid valve 104, 105, 1 12. The magnetic force of the electromagnetic actuator 102, 104 in this case exceeds the spring force of the valve spring 1 1 1 (Figure 2a), so that the armature 104 lifts the valve ball 105 from its valve seat and hereby opens the outlet throttle 1 12.

With the opening of the outlet throttle 1 12 can now fuel from the valve control chamber 106 in the overlying according to Figure 2b cavity, see. the arrows, and flow through a fuel return 101 back to an unillustrated fuel tank. The inlet throttle 1 14 prevents a complete pressure equalization between in the range of

High pressure port 1 13 applied rail pressure and the pressure in the valve control chamber 106, so that the pressure in the valve control chamber 106 decreases. As a result, the pressure in the valve control space 106 becomes smaller than the pressure in the chamber volume 109, which still corresponds to the rail pressure. The reduced pressure in the valve control chamber 106 causes a correspondingly reduced force on the control piston 15 and thus leads for opening the injection valve 10Oa, that is to say for lifting the valve needle 16 out of its valve needle seat in the region of the injection holes 10. This operating state is illustrated in FIG. 2b.

Then, that is, after lifting from the valve needle seat, performs the valve needle 1 16 primarily under the action of hydraulic forces in the chamber volume 1 19 and in the valve control chamber 106 has a substantially ballistic trajectory. In a sufficiently large driving time, during which the solenoid coil 102 is supplied with the drive current I, the valve needle 1 16 in its opening movement, however, also not shown

Reach the needle stroke stop, which defines the maximum needle stroke. In this case, it is spoken of an operation of the injection valve 100a in its full-stroke range.

Once the electromagnetic actuator 102, 104 (Figure 2a) to one end of the

Control period is no longer controlled by the control unit 22, presses the valve spring 1 1 1, the armature 104 as shown in Figure 2c, down, so that the valve ball 105 thereupon the outlet throttle 1 12 closes. As a result, the rail pressure builds up again in the control room 106. This now increased pressure in the control chamber 106 exerts a greater force on the control piston 15, which, together with the force of the nozzle spring 107, exceeds the force acting on the valve needle 16 in the region of the chamber volume 109 and the valve needle 16 thus returns to its position Closing spends.

The fuel injection is finished as soon as the valve needle 1 16 their

Valve needle seat reached in the area of the injection holes 1 10 and this closes, see. Figure 2c.

FIG. 3 schematically shows a time profile of the operating variables drive current I, stroke h of the valve needle 16 (FIG

Drive cycle in the context of fuel injection results.

First, from the time tθ, the electromagnetic actuator 102, 104 (FIG. 2a) of the injection valve 100a is energized in order to lift the magnet armature 104 or the valve ball 105 out of their valve ball seat in the region of the

To allow outlet throttle 1 12. The time tθ thus defines a beginning the drive duration defined by the drive signal I ti of the electromagnetic actuator 102, 104 and thus also the injector 100a.

The energization of the electromagnetic actuator 102, 104 lasts in the diagram indicated in FIG. 3 up to the end t1 of the actuation period ti and may also have different current values (not shown) over the actuation period ti.

Its fully open state, which is characterized by the maximum stroke hmax of the valve needle 1 16, the injection valve has 100a according to the in

Figure 3 mapped diagram after the time t01 reached. The delay t01-tθ results from the operating principle of the injection valve 100a described above with reference to FIGS. 2a, 2b, 2c.

A closing time t2 results according to FIG. 3 following the end t1 of FIG

Activation time ti. The closing duration t2 is composed in the configuration of the injector 100a according to the figures 2a, 2b, 2c of a holding delay time of the armature 104 and an adjoining closing time of the valve needle 1 16 together. Only at the end t3 of the closing time t2, the injection valve 100a again has its closed state.

In order to enable a precise fuel injection despite the undesirable closure period t2 and possibly occurring variations of latency in the operation of the injection valve 100a as well as specimen scattering between different injection valves 100a, 100b, 100c, 100d (FIG. 1), the activation duration is provided according to the invention ti is corrected in response to an individual correction value for the injector 100a to obtain a corrected drive duration.

Already in the context of a pure control can thus be made using the inventive correction value advantageously an adaptation of a special injection valve 100a, for example, to a standard injection valve.

For example, the case may occur that for a particular injector

100a eg due to a too soft valve spring the closing time t2 is undesirably large. As a result, a larger amount of fuel is injected at a fixed drive time specified as in a operated with the same drive time reference injection valve or the other injectors 100b, 100c, 100d of the engine 10. This deviation can by appropriate selection of the invention

Correction value for the considered injection valve 100a are compensated. In the present case, the correction value for the injection valve 100a under consideration is therefore selected such that the corrected activation duration is shorter than the predefined activation duration, whereby the influence of the too soft valve spring is reduced or completely compensated.

Conversely, if the valve spring is too hard, the activation duration ti can be corrected according to the invention to larger values in order to obtain the desired injection quantity.

Furthermore, the principle according to the invention advantageously provides the possibility of regulating the actuation duration ti, preferably as a function of a predefinable closing duration t2, to a desired value.

Figure 4 shows a functional diagram of an embodiment of the operating method according to the invention, which provides such a control.

From a predetermined by the control unit 22 (Figure 1), fuel quantity qdyn and the fuel pressure P in the common rail 16 (Figure 1) is determined by means of a map KF1 - as in the conventional systems since then - initially the control duration ti. Using the function block 210, to which the activation time ti is supplied on the input side, a correspondingly resulting closing duration t2 is determined, as it results during the operation of the injection valve 100a under the control of the activation duration ti. The functional block 210 can be realized, for example, by means of a model representing the operation of the fuel injection valve 100a. Alternatively, the functional block 210 may also be formed by the injection valve 100a itself, and the closing duration t2 resulting as a result of activation with the activation duration ti is detected, for example, by measurement. An adder 21 1 forms a control difference Δt 2 = t 2 -t 2m, where t 2m corresponds to a predefinable setpoint value for the closing duration t 2.

The control difference .DELTA.t2 is fed to a feedback member 212, which, for example, a multiplication of the control difference .DELTA.t2 with a predetermined

Factor, whereby the correction value tkorr for the drive time ti is obtained at the output of the feedback element 212. The correction value tkorr is subtracted by the adder 213 from the activation duration ti determined by means of the characteristic map KF1, so that according to the invention ti_korr is obtained for the corrected activation duration:

ti_korr = ti - tkorr.

The correction value ti_korr obtained according to the invention can now be advantageously used for the correction of the activation duration ti determined by means of the characteristic map KF1.

In the case of the realization of the function block 210 by a model representing the injection valve 100a, the correction value ti_korr can be used directly for driving the injection valve 100a for a subsequent operating cycle. If the function block 210 represents the injection valve 100a and its actual operation, the correction value ti_korr can also be taken into account, for example, directly in the characteristic diagram KF1 to form the activation duration ti.

A particularly efficient equalization of the injection valves 100a, 100b, 100c, 100d (FIG. 1) of the internal combustion engine 10 with respect to their injection quantities is given when the desired value t2m corresponds to a closing duration averaged over the injection valves 100a, 100b, 100c, 100d. This averaged closure duration t2m can be measured, for example during the operation of the

Internal combustion engine 10 can be determined.

The advantage of the operating method according to the invention is that the effects of specimen scatters and a sensitivity of the injected fuel quantity to environmental parameters such For example, pressure, temperature, viscosity of the fluid to be injected, etc. are reduced compared to conventional methods.

In particular, valve-individual long-term drift effects, which are for example due to wear, compensated as well as short-term

Changes resulting, for example, from variable boundary conditions such as temperature, fuel properties, return back pressure, valve seat deflection, and so on.

The operating method according to the invention is preferably applicable in a full-stroke operation of the injection valve 100a and ensures a valve-individual closing duration t2 at which the actually injected fuel quantity agrees as well as possible with a corresponding desired value.

By applying the method according to the invention is also a very efficient equality of the plurality of injection valves 100a, 100b, 100c, 100d in terms of the injected fuel quantity possible. In addition, the operating method according to the invention is able to compensate for the effect of external interventions, as they result, for example, in a deliberate increase in the armature stroke by impermissible Tuningmaßnahmen and the like.

The method according to the invention can advantageously be used as described above for servo valves 104, 105, 112 having injection valves 100a, 100b, 100c, 100d, in particular for common rail diesel systems, but can also be used with injectors which do not have a servo valve , eg in systems for gasoline direct injection.

The invention is based on the observation that a Nadelhubverlauf h and thus the injected fuel quantity, in particular in a Vollhubbetrieb the injector 100a is related to the closing time t2.

This effect is achieved by the provision according to the invention of the correction value tkorr and / or the control of the actuation duration ti or the latter based thereon

Closing time t2 exploited. In general, the operating method according to the invention can be carried out in all of the injection valves actuated by means of an electromagnetic actuator, in which an amount to be injected is predetermined over a corresponding activation period.

Claims

claims

1 . Method for operating an injection valve (10Oa), in particular an internal combustion engine (10) of a motor vehicle, in which a component of the injection valve (100a), in particular a valve needle (1 16), by means of an electromagnetic actuator (102, 104) is driven, and at in that the actuator (102, 104) is actuated by a drive signal (I) having a drive duration (ti) in order to inject an injection quantity dependent on the actuation duration (ti), characterized in that the actuation duration (ti) depends on the injection valve (100a) individual correction value (tkorr) is corrected to a corrected one

Control duration (ti_korr) to receive.

2. The method according to claim 1, characterized in that the

Control duration (ti) is controlled to a predetermined setpoint.

3. The method according to claim 2, characterized in that the desired value is determined as a function of a predefinable closing duration (t2).

4. The method according to claim 2 or 3, characterized in that the desired value as a function of a plurality of injection valves (100a, 100b,

100c, 100d) averaged closing duration (t2m) is determined.

5. The method according to any one of claims 3 to 4, characterized in that the closing period (t2) is determined dynamically from operating variables of the injection valve (100a).

6. The method according to any one of the preceding claims, characterized in that it is applied in a Vollhubbereich of the injection valve (100a).

7. Control unit (22) for operating an injection valve (100a), in particular an internal combustion engine (10) of a motor vehicle, wherein a component of the injection valve (100a), in particular a valve needle (1 16), by means of an electromagnetic actuator (102, 104) is drivable, and wherein the actuator (102, 104) with a drive time (ti) having a drive signal (I) is controllable to one of the drive time (ti) dependent Inject injection quantity, characterized in that the activation duration (ti) as a function of one for the

Injector (100a) individual correction value (tkorr) is correctible to obtain a corrected drive time (ti korr).

8. Control device (22) according to claim 7, characterized in that it is designed for carrying out the method according to one of claims 1 to 6.

A computer program comprising program code means for performing all the steps of the method of any one of claims 1 to 6 when the computer program is run on a computer or equivalent computer

Computing unit, in particular in a control device (22) according to claim 7, is executed.

A computer program product comprising program code means stored on a computer readable medium for carrying out all steps of the program

Method according to one of claims 1 to 6 perform when the computer program on a computer or a corresponding processing unit, in particular in a control device (22) according to claim 7, is executed.