WO2013000834A1

WO2013000834A1 - Fuel injection valve

Info

Publication number: WO2013000834A1
Application number: PCT/EP2012/062113
Authority: WO
Inventors: Holger Rapp; Helmut Clauss; Wolfgang Stoecklein; Thomas Pauer; Changyi Wang; Markus Rueckle; Matthias Schnell; Marco Beier
Original assignee: Robert Bosch Gmbh
Priority date: 2011-06-28
Filing date: 2012-06-22
Publication date: 2013-01-03
Also published as: DE102011078159A1; KR101858300B1; CN103620196B; CN103620196A; EP2726723B1; KR20140043096A; EP2726723A1

Abstract

The invention relates to a fuel injection valve (11), to an electrical circuit (100), and to a method. A first connection (70a) of a sensor device (70) is connected to a connection (HS) of an actuator (80). An additional connection (70b) of the sensor device (70) is connected to a reference potential (88). The sensor device (70) comprises a sensor (26) and a series resistor (90) connected in series with the sensor (26).

Description

description

title

Fuel injection valve prior art

The invention relates to a fuel injection valve according to the preamble of claim 1, and an electrical circuit and a method according to the independent claims.

Switching elements, such as relays or solenoid valves, in particular as

Injectors are used in an internal combustion engine, are exposed to high demands during operation and are therefore frequently monitored. This monitoring is done for example by an evaluation of currents and / or voltages of an actuator of the switching element. You can do this

in particular serve sensors that detect physical variables and convert into electrical quantities. The transfer of these quantities to one

Control unit or the like is generally associated with an increased effort in terms of the number of electrical lines.

In solenoid valves for gasoline direct injection of internal combustion engines electrical control variables of the magnetic circuit can be used to determine the closing time of a nozzle needle of the injection valve when the magnetic circuit actuates the nozzle needle directly. In this case, additional measuring lines or the like are often unnecessary. In contrast - for example, for diesel injection - there are versions of

Injectors, in which the magnetic circuit additionally actuates a servo valve, which subsequently controls a nozzle needle actuated high-pressure hydraulics. The closing time of the nozzle needle can not be determined from the movement of a magnet armature of the solenoid valve. From DE 10 2010 063 681 a method is known in which a

Measuring state is prepared in which at least one terminal of the actuator is at least temporarily decoupled from a reference potential and / or from a source controlling the actuator substantially. In the measuring state, at least one signal of at least one sensor of a sensor device is determined from at least one electrical potential at at least one connection of the actuator. Advantageously, lines to the actuator and the

Sensor device can be saved. Disclosure of the invention

The problem underlying the invention is achieved by a

Fuel injection valve according to claim 1 and solved by an electrical circuit and a method according to the independent claims. Advantageous developments are specified in the subclaims.

Characterized in that the sensor device comprises a sensor and a series resistor connected in series with the sensor and in a first phase in the control of an actuator, the current is limited by the sensor, a disturbance or damage of the sensor is advantageously prevented. By the in

Series connected to the sensor series resistor also result in terms of the design of the sensor advantages. The sensor may, for example, have a high capacity without adversely affecting the

Activation of the actuator result. In particular, high-capacity piezoelectric sensors can thereby be used. The capacitance of the sensor and the series resistor form a first low-pass first order, which advantageously reduces the above-described load on the sensor in the control of the actuator. In an advantageous development of the ohmic resistance of

Series resistor much larger than the ohmic resistance of the actuator. In the first phase much more power is supplied to the actuator than the sensor device. In the event of a short circuit of the sensor, the series resistor advantageously ensures that the actuator can continue to operate despite the short circuit. An electrical circuit advantageously comprises a capacitor between the one terminal of the actuator, to which the sensor device is connected. In a third phase, a signal from the sensor of the sensor device in

Dependence of a the electrical potential on the capacitor of the electrical circuit determined. In the third phase, the sensor has

Voltage source character. The series resistor and the capacitor of the electrical circuit form a second low-pass filter. Accordingly, high-frequency noise can be filtered out and the electrical potential at the capacitor of the electrical circuit is advantageously smoothed and thus there is an improved signal quality. The second low pass consisting of the series resistor of the sensor device and the capacitor of the electrical circuit is advantageously dimensioned such that the

Sensor signal is attenuated only slightly. In an advantageous development, the capacitance of the sensor is greater than that

Capacitance of the capacitor of the electric circuit. This is the

Time constant of the first low-pass filter is greater than the time constant of the second low-pass filter, which advantageously determines the sampling accuracy predominantly only from the first low pass.

In an advantageous embodiment, the actuator is substantially decoupled from the reference potential and / or from the driving source in a second phase before the third phase and after the first phase. By the

Decoupling the sensor signal is not degraded via the low-impedance actuator and the sensor signal can be measured.

In an advantageous embodiment, an error of the sensor is determined as a function of the electrical potential or a profile of the electrical potential at the capacitor of the electrical circuit. Depending on the detected error, an error signal is generated by the electrical circuit. Advantageously, it can thereby be taken into account, for example in the case of further operation of the actuator, despite the error that the electrical potential at the capacitor is no longer valid or defective. The electrical potential at the capacitor can thus be advantageously ignored or ignored in the activation of the actuator. A faulty sensor thus does not lead to a faulty operation of the actuator. The error signal can For example, the driver or Werkstattmitarbeiter be displayed, for example, to perform the replacement of the fuel injection valve or perform. For the invention important features can be found in the following

Drawings, wherein the features both alone and in different combinations for the invention may be important, without being explicitly referred to again. Hereinafter, exemplary embodiments of the invention below

Explained referring to the drawing. In the drawing show:

Figure 1 is a partial sectional view of a servo valve of a

Fuel injection valve with a magnetic switching member and a valve piece;

Figure 2 is a timing diagram of a control chamber pressure and a stroke of a valve member formed as a valve element of the servo valve of Figure 1;

Figure 3 is a simplified schematic of an embodiment of the

Connecting a sensor and a coil in a housing of a fuel injection valve; Figures 4 and 5 are each a schematic circuit diagram with a

Fuel injection valve and an electrical circuit for controlling the fuel injection valve;

FIG. 6 shows a schematic circuit diagram of a sensor device of the

Fuel injection valve in a first phase; and

FIG. 7 shows a further schematic circuit diagram of FIG

Fuel injection valve and the electrical circuit in a third phase. The same reference numerals are used for functionally equivalent elements and sizes in all figures, even in different embodiments. Figure 1 shows a partial sectional view of a servo valve 10 of a fuel injection valve 1 1 not further shown in detail

Internal combustion engine. The servo valve 10 is substantially

executed rotationally symmetrical about a longitudinal axis 12. In an upper portion of the drawing, a fixed to a (not shown) housing support plate 14 is shown in a vertically central region, a magnetic switching member 16 is shown, and in a lower portion is a housing-fixed valve member 18 with a hydraulic control chamber 20 and a on a valve needle, not shown, of the fuel injection valve 1 1 acting or firmly connected with such a valve needle connected valve piston 22.

The support plate 14 has in the region of the longitudinal axis 12 a support piston 24, with which a force-sensitive transducer 26 is operatively connected. The force-sensitive transducer 26 is in turn supported in the direction of the longitudinal axis 12 on the support plate 14. In the drawing above the non-positive transducer 26, two openings (without reference numerals) are arranged, through which lines for contacting the terminals 70a and 70b of a

Sensor device 70 are guided. The arrangement of the two openings is shown in the figure 1 only by way of example. The magnetic switching element 16 comprises a coil 30, which in a

Magnet core 32 is embedded, wherein the magnetic core 32 is pressed by a plate spring 34 against an annular armature stop 36. The armature stop 36 is in turn pressed by the diaphragm spring 34 by means of the magnetic core 32 against a diameter jump (no reference numeral) of a sleeve 38 fixed to the housing. Along a central region of the longitudinal axis 12 is a along the

Longitudinal axis 12 of play bearing mounted but radially held anchor bolt 40 is arranged on which an armature 42 is slidably disposed in the direction of the longitudinal axis 12. A lower end region 44 of the armature 42 in FIG. 1 can rest on a sealing portion 46 of the valve piece 18 forming a valve seat. The end portion 44 forms in this respect a valve element of the servo valve 10. The magnetic switching member 16 is like the other elements of the servo valve 10 in Essentially designed rotationally symmetrical, but only the right in the drawing half of a sectional view is shown. A guide diameter of the armature 42 and a seat diameter in the region of the sealing portion 46 are approximately equal.

The valve piece 18 defines the hydraulic control chamber 20 and the

Valve piston 22. The valve piston 22 is displaceable in the valve piece 18 in the direction of the longitudinal axis 12 and, as already mentioned above, with a valve element, not shown (nozzle or valve needle) fixedly coupled. In the drawing above the control chamber 20 this is connected via an outlet throttle 48 with a valve chamber 50. In the drawing right of the control chamber 20, an inlet throttle 52 is arranged, through which the control chamber 20 can be fed with a high pressure fluid 54. The fluid 54 is provided, for example, by a common-rail fuel system (not shown). A fluid space 56 in which the armature 42 and the

Anchor bolts 40 are arranged is with a not shown

Low pressure area connected.

As long as the coil 30 is not energized, the end portion 44 is pressed by a valve spring, not shown, against the sealing portion 46, the servo valve 10 is thus closed. Due to the pressure conditions in the control chamber 20, the valve piston 22 is pressed down in the drawing, so that the (not shown) valve needle closes. If the coil 30 is energized, the armature 42 by magnetic force in the direction of the magnetic core 32 against the

Anchor stop 36 moves. As a result, fluid flows from the control chamber 20 to the fluid chamber 56, so that the pressure in the control chamber 20 decreases and the valve needle with the valve piston 22 in Figure 1 can move upwards and open. The fuel injection begins. To close the energization of the coil 30 is terminated. By the valve spring, the end portion 44 is again pressed against the sealing portion 46, the servo valve 10 thus closes, and the outflow of fluid from the control chamber 20 is terminated. Since fluid continues to flow via the inlet throttle 52 into the control chamber 20, the

Valve piston 22 and with him the valve needle in Figure 1 down in

Closing direction pressed. The fuel injection ends. The closing time of the fuel injection valve 1 1 can be determined by the course of the force that the anchor bolt 40 against the

force-sensitive transducer 26 exercises, is evaluated. By such a force or force change, a voltage is built up in the latter or generates a current pulse or there is a change of a passive parameter of the sensor, for example its resistance or its capacitance, whereby a sensor signal is generated. The sensor signal can be detected by means of electrical circuits, as described below in FIGS. 4 and 5.

The force-sensitive transducer 26 may also be embodied as a sensor which alternatively or additionally detects a force and / or a pressure of the fluid 54 and / or a structure-borne noise of the support plate 14 or a housing of the fuel injection valve 1 1, so that the same

Opening times and / or closing times of the servo valve 10 can be determined. Force sensitive transducer 26 will therefore be generically referred to as sensor 26 below.

Figure 2 shows a temporal relationship between the pressure 160 in the valve chamber 50, the pressure 60 in the control chamber 20 and the stroke 62 of the valve piston 22 and the associated valve needle. In an upper diagram of Figure 2 are plotted on the ordinate, the pressure 60 in the control chamber 20 and the pressure 160 in the valve chamber 50, and in a lower diagram, the stroke 62 of the valve piston 22 is plotted on the ordinate. The pressure 60 is shown by a solid line, the pressure 160 by a dashed line. In the present case, a stroke 62 of zero means a closed injection valve. Both diagrams have on the abscissa an equal time scale t.

It can be seen that both at the beginning of the opening movement of the valve piston 22 at a time ta and at the end of the closing movement at a time tb, the course of the pressure 60 experiences clearly visible changes. Immediately before opening at time ta, there is a sudden

Pressure drop, when closing at time tb occurs a sudden increase in pressure. The pressure 160 in the valve chamber 50, which is identical with the pressure 60 in the control chamber 20 when the servo valve 10 is closed, acts on the anchor bolt 40 on the force-sensitive transducer 26, and thus can be converted into a sensor signal, so that the changes in the pressure 160 are reflected in the sensor signal and thus can be evaluated for determining, for example, the closing time.

Figure 3 shows a simplified schematic embodiment of the

Connection of the sensor device 70 and an actuator 80 in a housing 64 of the fuel injection valve 1 first The actuator 80 may comprise the coil 30 explained with reference to FIG. 1, but also other or further elements. In particular, the actuator 80 may be a part of a magnetic or piezo valve or else a magnetostrictive valve. The described methods are therefore also applicable to other actuator types. The connections HS and LS of the actuator 80 are isolated out of the housing 64 of the fuel injection valve 1 1 led out. The terminal 70a of the sensor device 70 is connected to the

Terminal HS of the actuator 80 is electrically conductively connected, the further terminal 70b of the sensor 26 is electrically conductively connected to an electrically conductive portion 66 of the housing 64 low impedance. The housing 64 in turn is electrically conductively connected to a reference potential 88, which in the present case is a ground potential of a motor vehicle containing the fuel injection valve 1 1. This is done by means of the mechanical attachment of the

Fuel injection valve 1 1, which is screwed for example in an engine block. This is not shown in the drawing.

The sensor 26 determines according to the illustration of Figure 2, the pressure 160 in the valve chamber 50 of the servo valve 10. About the terminal HS and LS of the actuator 80, a signal of the sensor 26 can be determined by an electrical potential at the terminal HS or LS of the actuator is detected. Due to the arrangement of the sensor 26 within the housing 64 is the

Signaling particularly robust and insensitive to disturbing

electromagnetic couplings.

Figure 4 shows a schematic circuit diagram with the fuel injection valve 1 1 and an electrical circuit 100 for controlling the

Fuel injection valve 1 1. The sensor device 70 comprises the sensor 26 and a series resistor 90, which is connected in series with the sensor 26. The terminal 70a of the sensor device 70 is connected to the terminal HS of the actuator 80 electrically connected. Alternatively, the terminal 70a of the

Sensor device 70 may also be connected to the connection LS of the actuator 80. The other terminal 70b of the sensor device 70 is electrically conductively connected to the reference potential 88. Both connections HS and LS of the actuator 80 are not connected to the reference potential 88, but operating states are conceivable in which the connection HS or LS is at least temporarily connected to the reference potential 88. Of course, the reference potential does not necessarily have to be connected to the vehicle ground, but can refer to another potential level.

Two drive lines 76 and 78 connect the terminals HS and LS of the actuator 80 to the electrical circuit 100. This electrical circuit 100 serves on the one hand for driving the actuator 80 and includes a driver circuit not explained in more detail. Furthermore, the electrical circuit 100 is used to determine a signal of the sensor 26, for which an unspecified explained

Evaluation circuit is included in the electrical circuit 100. to

Actuation of the actuator 80 is an unspecified source,

in particular a DC voltage source. The electrical circuit 100 and thus also the source is supplied via a potential or a supply voltage U _v .

Of course, another resistor may be located between the terminal 70a and the sensor 26. It is also self-evident that between the connection HS or LS of the actuator 80 and the connection 70a and between the connection 70b and the reference potential 88 more

Components such as resistors, coils or capacitors are located.

In a first phase of the actuator is connected by means of the electrical circuit 100 to the above-mentioned source, that is, connected to the source low resistance. In the first phase of the actuator 80 is thus energized and can bring, for example, the servo valve 10 of Figure 1 in a working position.

In a second phase, the actuator 80 is decoupled from the driving source by means of the electrical circuit 100. The current in the actuator 80 is ideally to zero, and thus, for example, the servo valve 10 of Figure 1 can go to its rest position.

In a third phase, a measurement state is established to evaluate the signal from the sensor 26. The third phase can also be initiated when, for example, residual energy is present in the actuator 80. The electrical circuit 100 now detects a potential U _{76 of} the control line 76 against the reference potential 88 in order to determine a voltage signal or current signal generated by the sensor device 70 or by the sensor 26. If the connection 70a of the sensor device 70 is connected to the connection LS of the actuator 80, the electrical circuit 100 determines an electrical potential U _{78 of} the control line 78 against the reference potential 88 in order to generate a signal generated by the sensor device 70 or by the sensor 26

Voltage signal or current signal to determine.

The area between the vertical lines 82 and 84 represents a wiring harness that includes, among other things, the drive lines 76 and 78. The connection 98 between the vertical lines 82 and 84 represents the connection in Figure 3 between the terminal 70b of the sensor device 70 and the reference potential 88 via the housing 64 and other components.

In the figure 4 right next to the line 84, the electrical circuit 100 is arranged. The electrical circuit 100 is connected to the reference potential 88 and is supplied by a power supply, not shown, with the potential U _v .

Furthermore, the electrical circuit 100 generates a signal 92, which is determined as a function of the potential U ₇₆ or U ₇₈ , wherein the potential U ₇₆ or U _{78 is influenced} by the signal of the sensor 26.

Due to the series resistor 90, which is connected in series with the sensor 26, more power is supplied to the actuator 80 in the control of the actuator 80 by means of the electrical circuit 100 in the first phase than the sensor device 70. For this purpose, the ohmic resistance of the series resistor 90th or the entire sensor device 70 is greater than the ohmic resistance of the actuator

80. In particular, the ohmic resistance of the series resistor 90 is essential greater than the ohmic resistance of the actuator 80, in particular at least by a factor of 5 greater, in particular at least by a factor of 10 larger.

The electrical circuit 100 comprises a capacitor C100 (not shown in FIG. 4) between the one connection HS or LS, at which the

Sensor device 70 is connected to the terminal 70a, and the reference potential 88. In the third phase, the signal of the sensor 26 of the sensor device 70 from the electrical potential U ₇₆ or the electrical potential U _{78 is} determined.

The sensor 26 is in particular a capacitive sensor and essentially represents a capacitor. A capacitance of the sensor 26 is connected to the sensor

Reference character C ₂ 6 is designated. The capacitance C ₂ 6 of the sensor 26 is greater than the capacitance C100 of the capacitor of the electrical circuit 100.

The electrical circuit 100 can determine a short circuit of the sensor 26 as a function of the electrical potential U ₇ 6 or U ₇ 8 or the course of the electrical potential U ₇₆ or U ₇₈ . In particular, as a function of the determined short circuit of the sensor 26, the electrical circuit 100 generates an error signal 94.

FIG. 5 shows a schematic circuit diagram with the fuel injection valve 1 1 and the electric circuit 100 for controlling the fuel injection valve 1 1. FIG. 5 essentially corresponds to FIG. 4, with only the position of the sensor 26 and the series resistor 90 in the sensor device

70 are reversed. Furthermore, the sensor device 70 with its connection 70a can also be connected to the connection LS of the actuator 80.

FIG. 6 shows a schematic circuit diagram of the sensor device 70 of FIG

Fuel injection valve 1 1 in the first phase regardless of the respective

Interconnection of the sensor device 70 with the actuator 80. A potential U _A drops at the series circuit of the series resistor 90 and the sensor 26 from. A potential U _B drops at the sensor 26. In the first phase of the actuator 80 is driven. The ohmic resistance of the series resistor 90 and the capacitance C ₂ 6 of the sensor 26 form a first first order low pass with respect to

Transfer function U _B / U _A. A first time constant ΤΊ this first Low pass results from the product of the ohmic resistance of the series resistor 90 and the capacitance C _{26 of} the sensor 26. By the

Series resistor 90 is limited in the first phase of the current through the sensor 26.

FIG. 7 shows a further schematic circuit diagram of the fuel injection valve 11 and of the electric circuit 100 in the third phase. In the third phase, the actuator 80 is substantially decoupled from the reference potential 88 and / or from the driving source. In the third phase, the signal of the sensor 26 via the potentials U ₇₆ and U _{78 is} detected. In the figure to the right of a line 86 is an equivalent circuit diagram of the electrical circuit 100 in the third phase. On the left of the vertical line 86 is an equivalent circuit diagram of the fuel injection valve 1 1 in the third phase.

The capacitance C _{26 of} the sensor 26 was charged by the source in the first phase and represents a voltage source in the third phase. The sensor 26 thus generates a potential U _c or a profile of the potential U _c detected by the electrical circuit 100 becomes. The ohmic resistance of the series resistor 90 and the capacitance C100 of the capacitor of the electrical circuit 100 form a second first-order low-pass filter. At the

Series connection consisting of the series resistor 90 and the capacitor of the electrical circuit 100 drops the potential U _c . At the capacitance C100 drops a potential U _D. The second low pass refers to the

Transfer function U _D / U _C - A second time constant T _{2 of} the second

Low pass results from the ohmic resistance of the series resistor 90 and the capacitance C100 of the electric circuit 100. The second time constant T _{2 of} the second low pass is substantially equal to or smaller than the first time constant Ti of the first low pass. In particular, the capacitance C _{26 is} greater than the capacitance C100 of the capacitor of the electrical circuit 100.

In the case of the implementation of the sensor 26 as a piezo sensor, it does not matter if the sensor 26 has been loaded or not. Even if the piezo sensor has not been charged, it will generate under mechanical stress

Charge shift a voltage.

Claims

claims

1 . Fuel injection valve (1 1) with an actuator (80) and a

Sensor device (70), wherein a first terminal (70a) of the

Sensor device (70) is connected to a connection (HS, LS) of the actuator (80), and wherein a further connection (70b) of the sensor device (70) is connected to a reference potential (88), characterized in that the sensor device (70 ) comprises a sensor (26) and a series resistor (90) connected in series with the sensor (26).

2. Fuel injection valve (1 1) according to claim 1, wherein the ohmic

Resistance of the series resistor (90) is substantially greater than the ohmic resistance of the actuator (80), in particular at least by a factor of 5 greater, in particular at least by a factor of 10 larger.

3. Fuel injection valve (1 1) according to claim 1 to 2, wherein the further

Connection (70b) of the sensor device (70) electrically conductive with at least one electrically conductive portion (66) of a housing (64) of the

Fuel injection valve (1 1) is connected.

4. An electrical circuit (100) for operating the fuel injection valve (1 1) according to one of claims 1 to 3, wherein in a first phase, the actuator (80) from a source of the electrical circuit (100) is controllable, characterized in that the electrical circuit (100) comprises a capacitor between the one connection (HS; LS) of the actuator (80) to which the sensor device (70) is connected and the reference potential (88), and in a third phase a signal (92 ) as a function of an electrical potential (U ₇₆ , U ₇₈ ) on the capacitor of the electrical circuit (100) can be determined.

5. Electrical circuit (100) according to claim 4, wherein in the third phase of the actuator (80) is not driven.

Electrical circuit (100) according to claim 4 or 5, wherein a capacitance (C ₂ 6) of the sensor (26) is greater than the capacitance (C100) of the capacitor of the electrical circuit (100).

The electrical circuit of claim 4, wherein in a second phase prior to the third phase and after the first phase, the actuator is substantially decoupled from the reference potential and / or the driving source.

8. Electrical circuit (100) according to one of claims 4 to 7, wherein of the electrical circuit (100) in dependence on the electrical potential (U ₇ 6; U ₇₈ ) or the course of the electrical potential (U ₇ 6; U ₇₈ ) an error of the sensor (26) can be determined, and that in dependence on the detected error, an error signal (94) from the electrical circuit

(100) can be generated.

9. An electrical circuit according to claim 8, wherein the error a

Short circuit of the sensor (26).

10. A method for operating the fuel injection valve (1 1) according to one of claims 1 to 3, wherein in a first phase, the actuator (80) is driven by a source of an electrical circuit (100), characterized in that the electrical circuit (100 ) a capacitor between the one terminal (HS, LS) of the actuator (80) to which the

Sensor means (70) is connected, and the reference potential (88) comprises, and that in a third phase, a signal (92) in response to an electrical potential (U ₇₆ ; U ₇₈ ) is determined at the capacitor of the electrical circuit (100) ,

1 1. The method of claim 10, wherein the ohmic resistance of

Series resistance (90) is substantially greater than the ohmic resistance of the actuator (80), in particular at least by a factor of 5 larger,

In particular, at least by a factor of 10 larger, and wherein in the first phase, the actuator (80) substantially more power is supplied as the

Sensor device (26).

12. The method of claim 10 or 1 1, wherein a capacitance (C ₂ 6) of the sensor (26) is greater than the capacitance (C100) of the capacitor of the electrical circuit (100).

13. The method according to any one of claims 10 to 12, wherein in a second phase before the third phase and after the first phase of the actuator (80) from the reference potential (88) and / or from the driving source is substantially decoupled.

14. The method according to any one of claims 10 to 13, wherein of the electrical circuit (100) in dependence on the electrical potential (U ₇₆ ; U ₇₈ ) or the course of the electrical potential (U ₇₆ ; U ₇₈ ) a fault of the sensor ( 26), and that an error signal (94) is generated by the electrical circuit (100) in response to the detected error.

15. The method of claim 14, wherein the error is a short circuit of the sensor (26).