DE102017203001A1 - Switch valve, sensor module or actuator module with protective circuit - Google Patents

Abstract

Arrangement comprising an electrical component (21, 51) for a switching valve (1), in particular for engine fuel (4), and a housing (11, 11a; 22; 52) accommodating the component (21, 51), the component (21 , 51) via the outside of the housing (11, 11a; 22; 52) guided contacts (24a-24d) with at least one control unit (31, 32) is connectable, wherein two contacts (24a, 24b, 24c, 24d) via a voltage limiter (25) connected in parallel with the component (21, 51), wherein the voltage limiter (25) abruptly reduces its electrical resistance when the voltage U dropping above it exceeds a predetermined threshold value Us, and / or that on the current path between two contacts (24a, 24b, 24c, 24d) a current limiter (26) to the device (21, 51) is connected in series.Aktorbaugruppe (2) or sensor assembly (5), which is mounted as a whole in a switching valve (1) , with the arrangement. Switching valve (1), in particular for Mot or fuel (4), with the arrangement, the actuator assembly (2) and / or the sensor assembly (5).

Description

The present invention relates to switching valves and sensor assemblies or actuator assemblies for switching valves, with which in particular fuel can be metered into the combustion chamber of an engine.

State of the art

An engine fuel injector typically includes at least one actuator that is capable of exerting a force on a valve member of the injector upon application of a current and / or voltage. By this force, the valve element is moved and opened or closed in the sequence of the injector.

The development of the injectors is on the one hand to the fact that in addition to the known magnetic actuators novel actuator concepts, such as piezoelectric actuators, are used. On the other hand, sensors are increasingly being integrated in injectors to monitor correct operation and, in the end, to comply with the time schedule for metering the engine fuel with even greater precision. Injectors with sensors are for example from the DE 10 2007 008 617 A1 , from the DE 10 2009 002 895 A1 and from the EP 1 321 660 B1 known.

Disclosure of the invention

In the context of the invention, an arrangement of an electrical component for a switching valve, which is particularly suitable for motor fuel, and a device housing accommodating housing developed.

The switching valve can in particular decide how much fuel is supplied to the combustion chamber. Such a switching valve can meter the fuel, for example, in a suction pipe, where it is mixed with combustion air. From the suction pipe, the fuel can then be metered via a further valve in the combustion chamber of the engine. But the switching valve may also be, for example, an injector, which can meter the fuel, for example, directly into the combustion chamber of the engine.

The component can be connected to at least one control unit via contacts guided to the outside of the housing.

For example, the component may advantageously be designed as an actuator, which upon application of a current, and / or with a voltage, is able to exert a force on a valve element of the switching valve in order to open and / or close the switching valve. Alternatively or in combination, the component can also be advantageously designed as a sensor for detecting at least one physical measured variable.

The switching valve does not necessarily have to have an actuator. The switching valve may, for example, be a valve which alone opens or closes depending on the pressure of the supplied medium, for example engine fuel.

According to the invention, two contacts are connected via a voltage limiter connected in parallel with the component, wherein the voltage limiter abruptly reduces its electrical resistance when the voltage U dropping above it exceeds a predetermined threshold value Us. Alternatively or in combination with this, a current limiter is connected in series with the component on the current path between two contacts.

It has been recognized that the development of the actuators and sensors, in particular, is leading to more and more powerful components with more and more functionality. In particular, increasingly more microelectronics is being integrated into sensors. On the other hand, a spatially increasingly tight integration of functionality results in the devices becoming more susceptible to excessive voltages and currents. For example, microelectronic devices are susceptible to electrostatic discharge or misconnections, such as reverse polarity or swapping the actuator and sensor connections. To avoid damage due to electrostatic discharges, for example, for the actuator assembly, the sensor assembly or the switching valve as a whole, which was previously not a vulnerable part, an ESD handling must be reintroduced with correspondingly increased costs. In that regard, the voltage limit is more important than the current limit, since an increased voltage can lead to a damaging breakdown within a microelectronic device, even if only a small current flows.

This ESD handling is no longer necessary according to the invention. For this purpose, for example, an actuator assembly or sensor assembly, which is mountable as a whole in a switching valve, comprise an arrangement according to the invention. The actuator assembly, or the sensor assembly, may be particularly advantageously designed as an arrangement according to the invention. In particular, the sensor assembly, and / or the Aktorbaugruppe, regardless of the remaining components of the switching valve may be arranged in a separate housing, which is added to the switching valve. So it can be a housing for the sensor assembly, a housing for the actuator assembly or both a housing for the sensor assembly and a housing for the actuator assembly may be present. The sensor assembly and the actuator assembly may also form a common assembly and be arranged in a common housing.

However, the housing in which the component is arranged does not necessarily have to be a separate housing of the sensor module, and / or of the actuator assembly. The housing of the switching valve as a whole also fulfills the function in the context of the invention that the component is safe from immediate access and is only electrically accessible via the contacts protected by the voltage limiter and / or by the current limiter. For example, the component can be arranged in a recess in the housing of the switching valve. Thus, for example, the switching valve may optionally include an arrangement according to the invention or an actuator assembly or sensor assembly with this arrangement.

The measures according to the invention protect the arrangement, or an actuator assembly, a sensor assembly or a switching valve with this arrangement, but not only during handling, but also in repair, maintenance and testing of the device in which the switching valve is installed. For example, while the terminals of the switching valve and the control electronics to be connected thereto can be coded such that in the normal assembly of the switching valve in the vehicle interchanges of connections are prevented, come with maintenance tools with universal terminals used with which the coding can be bypassed. In general, the arrangement, or an actuator assembly, a sensor assembly or a switching valve with this arrangement, more robust against electrical influences from the outside.

It is important in particular in the case of a component designed as a sensor that the voltage limiter changes its resistance abruptly, thus discontinuously, when the voltage dropping above it exceeds the threshold value. Typical sensors have only a small self-capacitance. If the sensor is constantly bridged with a resistor which is so small that the expected overvoltages can no longer damage the sensor, the sensor's measuring signal is constantly falsified. Normally, as the voltage limiter changes its resistance, its resistance can be so high that the measurement signal is not significantly affected, while at over-voltage it can become so low that the overvoltage is reliably conducted past the sensor. The exact amount of resistance change is secondary and depends, inter alia, on the sensitivity of the sensor and the expected overvoltage.

The sensor may have a common reference potential with an actuator of the switching valve, or it may be galvanically isolated from the actuator. In particular, in the latter case, the sensor without the protective measures according to the invention is particularly sensitive to overvoltages, since no charges can be absorbed by the capacity of the actuator.

In a particularly advantageous embodiment of the invention, the voltage limiter is self-resetting, that is, it resumes its original electrical resistance when the increased voltage that has given rise to the resistance reduction no longer exists. In this way, no intervention is required to restore the operational readiness after the interception of an increased voltage.

For example, the voltage limiter can advantageously comprise a diode, a Zener diode, a varistor, a suppressor diode, a TVS diode and / or a gas discharge tube. He is then particularly suitable to protect a designed as a capacitive actuator or sensor device. In addition, diodes are also suitable for eliminating incorrect polarity.

At the same time, the voltage limiter can also limit the current through the component, because this current is linked via the internal resistance of the component to the voltage drop across it. Alternatively or in combination with this, however, a separate current limiter may also be provided, which opens the circuit when the current flowing through it exceeds a predetermined threshold value.

Such a current limiter can be a fuse in the simplest case. Their replacement in a workshop causes costs, but much less than a complete replacement of an injector. Already a passenger car injector for a diesel engine costs from about 600 € upwards.

In a particularly advantageous embodiment of the invention, the current limiter is a self-resetting fuse. Such a fuse may include, for example, a PTC resistor, which is suddenly high impedance with increasing current. When the current decreases and the PTC resistor cools again, it resumes its original resistance.

The determination of the increased current in the detour via the temperature increase is in any case slower than the direct electrical Detecting an increased voltage through the voltage limiter. If the reaction speed of the current limiter alone is insufficient, it can therefore advantageously be supplemented or replaced by a voltage limiter.

The current limiter does not necessarily limit the absolute value of the current. In a further advantageous embodiment of the invention, the current limiter limits the rate of current rise. If the cause of the increased current is a contact with an increased voltage, behind which, however, only a limited amount of charge, so is the emergence of an excessive current peak delayed at least until the charge is consumed. Electrostatic discharges in particular generate high voltages, but these only drive a very small amount of charge.

Advantageously, there is the voltage limiter, and / or the current limiter, within the housing of the arrangement, which may be the housing of the sensor assembly, the actuator assembly or the switching valve as a whole at the same time. In this way, it is ensured that the component is accessible only via the guided to the outside of the housing contacts, which are protected by the voltage limiter, and / or by the current limiter.

Further measures improving the invention will be described in more detail below together with the description of the preferred embodiments of the invention with reference to figures.

list of figures

• 1 Schaltventil 1 mit Sensorbaugruppe 5, in der der Sensor 22 mit Spannungsbegrenzer 25 und Strombegrenzer 26 geschützt ist, wobei Aktorbaugruppe 2 und Sensorbaugruppe 5 in einem gemeinsamen Gehäuse 22=52 untergebracht sind;
• 2 Schaltventil 1 mit Aktorbaugruppe 2 im Gehäuse 11 des Schaltventils 1 und Sensorbaugruppe 5 in separatem Gehäuse 52;
• 3 Schaltventil 1 mit Sensorbaugruppe 5 in Aussparung 11a des Gehäuses 11 des Schaltventils 1;
• 4 Schaltventil 1, das ohne Aktor 21 durch den Druck des Motorkraftstoffs 4 öffnet;
• 5 Zeitverlauf der über dem geschützten Sensor 22 abfallenden Spannung U(t) bei einer kurzzeitigen Überspannung (Kurve A) und bei einer länger anhaltenden Überspannung (Kurve B); zum Vergleich möglicher Spannungsverlauf bei ungeschütztem Sensor 22 (Kurve C).

It shows:

• 1 Switching valve 1 with sensor assembly 5, in which the sensor 22 is protected with voltage limiter 25 and current limiter 26, wherein actuator assembly 2 and sensor assembly 5 are housed in a common housing 22 = 52;
• 2 Switching valve 1 with actuator assembly 2 in the housing 11 of the switching valve 1 and sensor assembly 5 in a separate housing 52;
• 3 Switching valve 1 with sensor assembly 5 in recess 11a of the housing 11 of the switching valve 1;
• 4 Switching valve 1, which opens without actuator 21 by the pressure of the engine fuel 4;
• 5 Time course of the voltage U (t) dropping across the protected sensor 22 in the case of a short-time overvoltage (curve A) and with a prolonged overvoltage (curve B); for comparison possible voltage curve in unprotected sensor 22 (curve C).

To 1 comprises the sectional drawing drawn schematically, designed as an injector switching valve 1 a housing 11 with a nozzle opening 12 , The nozzle opening 12 is from a nozzle needle 13 with an in 1 exaggerated big drawn in needlepoint 14 locked. For this purpose, the needle tip 14 in the idle state of the switching valve 1 through the closing pressure springs 16 in the direction of the nozzle opening 12 pressed. The engine fuel 4 becomes the switching valve 1 over the inlet 17 fed.

The nozzle needle 13 is with a ferromagnetic anchor 15 coupled, of the designed as a magnet assembly actuator assembly 2 is operable. The actuator assembly 2 includes an electromagnet 21 , When the electromagnet 21 energized becomes the anchor 15 attracted and the needle point 14 from the nozzle opening 12 lifted off, leaving the switching valve 1 is opened and engine fuel 4 from the nozzle opening 12 can escape. Furthermore, a sensor module 5 provided, for example, a temperature sensor 51 includes.

The sensor assembly 5 and the actuator assembly 2 Together, they form a single unit that is in a common housing 22 . 52 is arranged. The electromagnet 21 and the temperature sensor 51 So are in the same housing 22 . 52 ,

The temperature sensor 51 is a semiconductor device and therefore much more sensitive to overvoltages and overcurrents than the electromagnet 21 , Therefore, between the contacts 24a and 24b that the temperature sensor 22 with the outside of the housing 22 . 52 connect, a parallel to the temperature sensor 51 connected voltage limiter 25 switched, ie, the contacts 24a and 24b are over the voltage limiter 25 connected. Exceeds the above the temperature sensor 22 decreasing voltage U the threshold Us, the resistance of the voltage limiter decreases 25 by leaps and bounds. The overvoltage is thus short-circuited and the temperature sensor 51 kept away.

Furthermore, in the current path between the contacts 24a and 24b also a current limiter 26 connected. Exceeds in the circuit between the contacts 24a and 24b flowing current I the threshold I _S , the circuit is through the current limiter 26 opened, ie interrupted.

The electromagnet 21 is about the contacts 24c and 24d with the outside of the housing 22 . 52 connected. Because the electromagnet 21 is comparatively insensitive, he is in the in 1 embodiment not shown by a voltage limiter 25 or a current limiter 26 protected.

The temperature sensor 51 is through an evaluation 31 read. The electromagnet 21 is through a driver circuit 32 driven. The ground contact 24b of the temperature sensor 51 is with the ground contact 24c of the electromagnet 21 connected. Thus, the electromagnet 21 and the temperature sensor 51 a common reference potential.

2 shows a further embodiment of the switching valve 1 , In contrast to 1 Here is the sensor assembly 5 not with the actuator assembly 2 arranged in a common housing. Instead, the actuator assembly 2 with the electromagnet 21 inside the case 11 of the switching valve 1, while the sensor assembly 5 in a separate housing 52 is housed, the outside of the housing 11 the switching valve 1 is attached. The housing 52 the sensor assembly 5 is to the housing 11 of the switching valve 1 out, so that the temperature sensor 51 the temperature T of the housing 11 the switching valve 1 can measure directly.

3 shows a further embodiment of the switching valve 1 , In contrast to 2 Here is the sensor assembly 5 not arranged in a separate housing 52, but in a recess 11a of the housing 11 the switching valve 1 ,

4 shows a further embodiment of the switching valve 1 , The structure is connected to the in 2 shown switching valve 1 ajar with the difference that no actor 21 and accordingly no actuator assembly 2 is available. Instead, the nozzle needle 13 the switching valve 1 to a plate 19 coupled, via a flexible, circumferential membrane 18 sealing with the housing 11 of the switching valve 1 connected is. Motor fuel 4 gets out of a reservoir via the remote solenoid valve 42 and the line 43 fed and pushes the effective area 19a of the plate 19 upwards. Is this due to the pressure of engine fuel 4 applied force greater than the closing force of the compression springs 16 , the top rises 12 the nozzle needle 13 from the case 11 the switching valve 1 off, and the switching valve 1 opens.

5 clarifies the protective effect of the voltage limiter 25 on the temperature sensor 51 , Plotted is the curve U (t) of the above the temperature sensor 51 decreasing voltage U as a function of time t for various assumed disturbances. Furthermore, the voltage level U _{D is} drawn, from the damage of the temperature sensor 51 threatening. The threshold voltage U _{S of} the voltage limiter 25 is chosen so that it lies below U _D with a certain safety distance.

Curve A shows the curve U (t) of the voltage U at the temperature sensor 51 in an exemplary electrostatic discharge. The voltage U rises steeply until the threshold voltage U _{S of} the voltage limiter 25 is reached. The voltage limiter 25 quickly becomes low-ohmic and short-circuits the voltage U so that it begins to sink immediately, almost as fast as it has risen. If at the time t _1, a large part of the charge introduced has drained and the voltage U has dropped significantly, the voltage limiter 25 with a certain switching hysteresis again high impedance. The discharge of the charge is then significantly slowed down. At about the time t ₂ , the charge then tilts to the end, and the voltage U drops comparatively quickly to zero.

Curve B shows the curve U (t) of the voltage U at the temperature sensor 51 in an exemplary Falschbeschaltung by connecting the temperature sensor 51 to the Bestromungsanschluss for the electromagnet 21 at the driver circuit 32 , The voltage U rises quickly, but is intercepted at the level Us. In contrast to the electrostatic discharge, here the voltage source constantly supplies new charge, so that the voltage U is kept at the level U _S. At time t ₃ , the driver circuit 32 off. However, this only becomes noticeable from the time t ₄ , when so much charge has flowed out of the circuit that the voltage U drops below the level U _S and finally to zero. In contrast to curve A, the voltage U drops much more slowly due to the significantly larger amount of charge stored, and this increase is achieved by resetting the voltage limiter 25 in the high-impedance state does not slow further.

Curve C shows for comparison the course U (t) of the voltage U at the temperature sensor 51 for the same false-wiring in the event that the temperature sensor 51 not by a voltage limiter 25 or current limiters 26 is protected. The rise of the voltage U is then above the level U _D , from which the temperature sensor 51 damaged, continues. Damage of the temperature sensor 51 makes itself felt by the fact that its semiconductor breaks more and more through the overvoltage, so that the resistance is reduced and the increase of the voltage U is slowed down. If at time t _3, the driver circuit 32 is switched off, the voltage U falls again, and indeed with the same time constant as in curve B. From the time t ₄ , where the voltage U the level U _S passes down, therefore, the curve of curve C is identical to the course of curve B. However, the temperature sensor is 51 now sustainably damaged by the partial breakdown of its semiconductor under the overvoltage.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102007008617 A1 [0003]
• DE 102009002895 A1 [0003]
• EP 1321660 B1 [0003]

Claims (12)

Arrangement comprising an electrical component (21, 51) for a switching valve (1), in particular for engine fuel (4), and a housing (11, 11a; 22; 52) accommodating the component (21, 51), the component (21 , 51) is connected to at least one control device (31, 32) via contacts (24a-24d) guided to the outside of the housing (11, 11a; 22; 52), characterized in that two of the contacts (24a, 24b, 24c, 24d) are connected via a voltage limiter (25) connected in parallel with the component (21, 51), wherein the voltage limiter (25) abruptly reduces its electrical resistance when the voltage U dropping above it exceeds a predetermined threshold value U _S , and / or in that a current limiter (26) is connected in series with the component (21, 51) on the current path between two contacts (24a, 24b; 24c, 24d). Arrangement according to Claim 1 , characterized in that the electrical component (21, 51) as an actuator (21) is formed, which upon application of a current and / or with a voltage, a force on a valve element (13, 14, 15) of the switching valve (1) to exercise for the purpose of opening and / or closing the switching valve (1). Arrangement according to one of Claims 1 to 2 , characterized in that the electrical component (21, 51) is designed as a sensor (51) for detecting at least one physical measured variable. Arrangement according to one of Claims 1 to 3 , characterized in that the voltage limiter (25) is self-resetting. Arrangement according to Claim 4 , characterized in that the voltage limiter (25) comprises a diode, a Zener diode, a varistor, a suppressor diode, a TVS diode and / or a gas discharge tube. Arrangement according to one of Claims 1 to 5 , characterized in that the current limiter (26) opens the circuit when the current flowing through it I exceeds a predetermined threshold I _S. Arrangement according to Claim 6 , characterized in that the current limiter (26) comprises a self-resetting fuse. Arrangement according to one of Claims 1 to 7 , characterized in that the current limiter (26) limits the current slew rate. Arrangement according to Claim 8 , characterized in that the current limiter (26) comprises an inductor. Arrangement according to one of Claims 1 to 9 , characterized in that the voltage limiter (25), and / or the current limiter (26) within the housing (11, 11a, 22, 52) is arranged. Actuator assembly (2) or sensor assembly (5), which as a whole in a switching valve (1) can be mounted, comprising at least one arrangement according to one of Claims 1 to 10 , Switching valve (1), in particular for engine fuel (4), comprising at least one arrangement according to one of Claims 1 to 10 , and / or at least one actuator assembly (2) or sensor assembly (5) according to Claim 11 ,

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