Device for conveying a liquid additive

Abstract

Device (1) for conveying a liquid additive comprising an additive conveying assembly (2) and an electronics assembly (3), wherein the additive conveying assembly (2) has at least one hydraulic component (4) for conveying the liquid additive, wherein all electrical connections (5) of the at least one hydraulic component (4) are brought together in a first connector (6) on the additive conveying assembly (2), and wherein the electronics assembly (3) has a second connector (7) which is connectable to the first connector (6), wherein the first connector (6) and the second connector (7) are connected to each other and form a plug connection (8) when the electronics assembly (3) and the additive conveying assembly (2) are connected to each other, wherein the additive conveying assembly (2) has a pot-shaped housing (9) and the electronics assembly (3) has a cover (10) for the pot-shaped housing (9). exhibitsand the pot-shaped housing (9) is closed by the lid (10) when the electronics assembly (3) and the additive conveying assembly (2) are connected together.

Description

The present invention relates to a device for conveying and metering a liquid additive. Such a device can be used, for example, in a motor vehicle in order to supply a liquid additive to an exhaust gas treatment device of the motor vehicle.In motor vehicles with diesel internal combustion engines, exhaust gas treatment devices are used, into which a liquid additive is supplied. The liquid additive is then used to reduce, for example, nitrogen oxide compounds in the exhaust gas of the internal combustion engine. This is done with the aid of the selective catalytic reduction (SCR method, SCR=selective catalytic reduction). In the SCR method, the liquid additive typically used is urea-water solution, which is converted into ammonia in the exhaust gas. The ammonia is then used to convert nitrogen oxide compounds in the exhaust gas to harmless substances such as water (H 2 O), nitrogen (N 2) and / or carbon dioxide (CO 2). A 32.5 percent urea-water solution, which is available under the trade name AdBlue ® has currently become accepted as the liquid additive. A liquid additive used in the context of exhaust gas purification is frequently also referred to as a reducing agent or as a reducing agent precursor. Such a device is known from DE 10 2010 062 982 A1.A device for conveying and metering a liquid additive for a motor vehicle should function as far as possible in the manner of an (independent) black box system. A black box system is understood to mean a system to which a metering request for metering the liquid additive is transferred and which thereupon delivers from a tank an amount of the liquid additive corresponding to the metering request. In order to meet this requirement, it is advantageous if electronic components are present within the device, which components correspondingly process the metering requirement in order to control, operate, etc., the components of the metering device in this way. For example, the information about a requested quantity of liquid additive can thus be converted into a control variable for the operation of a feed pump in the device.In addition, a device for conveying a liquid additive should be able to be produced as cost-effectively as possible and able to be maintained as easily as possible.Proceeding from this, it is the object of the present invention to solve the technical problems described in a particularly advantageous manner. In particular, a particularly cost-effective device for conveying a liquid additive with electronic components for controlling the conveyance of the liquid additive is to be presented, which is simplified in particular with regard to assembly and maintenance compared to known systems.These objects are achieved with a device according to the features of claim 1. The features listed individually in the patent claims can be combined with one another in any desired, technologically meaningful manner and can be supplemented by features and illustrative facts from the description, wherein further embodiment variants of the invention are shown.The device for conveying a liquid additive has an additive conveying assembly and an electronics assembly, wherein the additive conveying assembly has at least one hydraulic component for conveying the liquid additive, wherein all electrical connections of the at least one hydraulic component are led together in a first plug connector on the additive conveying assembly, and wherein the electronics assembly has a second plug connector which can be connected to the first plug connector, wherein the first plug connector and the second plug connector are connected to one another and form a plug connection when the electronics assembly and the additive conveying assembly are connected to one another, wherein the additive conveying assembly has a pot-shaped housing and the electronics assembly has a cover for the pot-shaped housing, and the pot-shaped housing is closed by the cover when the electronics assembly and the additive conveying assembly are connected to one another.The device is preferably divided (in the manner of a set) such that all (active) components which serve for conveying the liquid additive or which are in contact with the liquid additive are arranged in / on the additive conveying assembly. These components, referred to herein as hydraulic components, are, for example, a pump that performs the delivery of the liquid additive, valves that control the direction of flow of the liquid additive through the channels of the device, and sensors with which the liquid additive is monitored and which are accordingly in contact with the liquid additive. When a plurality of such hydraulic components are provided, all the ports of these hydraulic components are merged in the first connector. The first plug connector thus represents a collecting connection, via which all hydraulic components of the device can be contacted. The additive delivery assembly is thus in particular a pre-assembled separate structural unit which can be mounted, for example (independently) in / on a holder on the motor vehicle or tank.The electronics module constitutes in particular a pre-assembled separate module which can be attached to the additive conveying module. The electronics module has a second plug connector, which can be connected to the first plug connector, in order that the hydraulic components of the device are electrically contacted. The plug connection of the first plug connector and the second plug connector is also formed during the assembly step of connecting the additive conveying assembly to the electronics assembly, i.e. in particular directly when the two assemblies are joined together. The first plug connector and the second plug connector are arranged for this purpose such that, during the assembly of the additive delivery assembly to the electronics assembly, the first plug connector and the second plug connector come into contact with one another accordingly by themselves, so that the plug connection is formed.This construction of the additive conveying assembly and the electronics assembly of the device makes it possible to mount the additive conveying assembly and the electronics assembly first independently of one another and to combine them to form the device in a simple final mounting step. This final assembly step requires particularly little effort due to the described advantageous design of the first plug connector and the second plug connector.Preferably, the first plug connector of the electronics assembly is attached to the electronics assembly in such a way that it cannot move relative to the electronics assembly. In particular, the first plug connector does not yield when it is pressed against the second plug connector in order to form the plug connection. The second plug connector on the additive conveying assembly, on the other hand, is preferably movable relative to the additive conveying assembly and moves when the plug connection is formed. This movability of the second plug connector makes it possible to compensate for manufacturing tolerances.In addition, it is made possible that different additive conveying assemblies and different electronic assemblies can also be combined for different requirements. For example, different additive conveying assemblies can be designed for different conveying capacities. It is possible, for example, to provide different additive conveying assemblies with different pump capacities, all of which can be combined with a common electronic assembly. This reduces the number of the necessary different assemblies and components that have to be stored in order to be able to keep available a supply from different devices for conveying a liquid additive.It is also possible that different electronics modules can be provided for a specific additive conveying module, which electronics modules can be adapted, for example, to the electronics of different motor vehicle types (for example, of different motor vehicle manufacturers). This also reduces the number of the necessary different assemblies and components which are necessary in order to be able to keep available a supply of different devices for conveying a liquid additive.The additive conveying assembly and the electronics assembly can each have guide means which assist the correct positioning of the two assemblies with respect to one another during assembly. These guide means can be formed, for example, by openings or bores on the additive conveying assembly and corresponding pins on the electronics assembly or vice versa. In this case, the pins are configured to engage in the openings or bores, so that the two assemblies are guided on one another during assembly.The cover preferably has a depression and / or a cavity, where the electronic components of the electronic assembly are arranged. The construction of the device with a cover and a pot-shaped housing makes it possible for both the components within the additive conveying assembly and the components within the electronics assembly to be freely accessible in each case before the device is mounted, that is to say before the electronics assembly and additive conveying assembly are connected. By connecting or mounting additive delivery assembly and electronics assembly, the device is closed off (preferably in a fluid-tight manner-with the exception of the desired inlet and outlet channels). This reduces the effort required for the assembly of the device as a whole. At the same time, a very good possibility for servicing the device is provided because the components within the device are directly accessible when the electronic assembly and the additive conveying assembly are separated from one another again (assembly type and electrically).The housing of the additive delivery assembly is preferably at least partially disposed within an interior of a liquid additive tank. The housing preferably extends from a tank wall of the tank into an interior space of the tank filled with liquid additive, wherein an opening of the housing points to an outer side of the tank wall. This opening can be closed by the cover of the electronics assembly.Furthermore, the device is advantageous if the pot-shaped housing is part of a tank wall of a tank for the liquid additive.A tank for the liquid additive is preferably a plastic tank, which can be manufactured, for example, by an injection molding method. It is particularly advantageous if the housing is part of this tank wall of the tank. The tank wall of the tank can have, for example, a section-wise inversion into the tank interior, which inversion is accessible from an outer side of the tank. The hydraulic components for conveying the liquid additive can be arranged in this indentation. The inversion is preferably pot-shaped when considered per se. A pot-shaped configuration of the inversion means, in particular, that (when the remaining tank wall around the inversion is removed) the inversion has a pot shape.Since the housing of the additive conveying assembly is part of a tank wall of a tank for the liquid additive, it is possible to produce the housing of the additive conveying assembly particularly cost-effectively and easily. At the same time, a particularly good tightness of the tank results because no fluid-tight connection has to be produced between the housing and the tank wall.Furthermore, the device is advantageous if at least the first plug connector or the second plug connector abuts against a stop when the electronic assembly and the additive conveying assembly are connected to one another, and wherein during the connection the first plug connector and the second plug connector are pressed into one another by means of the stop.The stop supports the first connector and / or the second connector to press the first connector and the second connector into each other to form the connector. The stop can have a spring element which presses against the first plug connector or against the second plug connector during the connection and in the process exerts a defined force which ensures a secure connection of the plug connectors.It is particularly advantageous if the spring element is a plastically deformable spring element which experiences a plastic deformation during the connection of the first plug connector and the second plug connector. This makes it possible to ensure that the first plug connector and the second plug connector are pressed into one another with a precisely defined force. The precisely defined force is precisely predefined by the elastic rearward expansion of the spring element after the plastic deformation. This is also the case if manufacturing tolerances with respect to the distance of the first plug connector and the second plug connector have not been observed particularly accurately, because the elastic return expansion of a plastically deformed spring element is at least partially independent of the previously effected plastic deformation of the spring element.Furthermore, the device is advantageous if at least the first plug connector or the second plug connector have a movable electrical connection line, so that the first plug connector and / or the second plug connector remains connected when the electronics assembly and the additive delivery assembly are released from one another.Preferably, the connecting line is not itself elastic, but is designed in the form of at least one loop, so that the first plug connector or the second plug connector can be detached from the respective other module. The first plug connector and the second plug connector preferably only loosely abut on the respective assembly. When the connector is formed, a mechanical force holds the connector together. By means of such a configuration, it is possible to separate the additive conveying assembly and electronics assembly from one another, for example for maintenance purposes.Furthermore, the device is advantageous if at least the first plug connector or the second plug connector has a closure which can be activated in order to disconnect the plug connection. This closure comprises, for example, at least one lever element which can be actuated so that the first plug connector and the second plug connector are levered apart (independently of one another when the structural units are released). Preferably, the closure is arranged to be accessible when the electronics assembly and the additive delivery assembly are released from each other.Preferably, the first plug connector and the second plug connector are connected to one another in the plug connection such that vibrations do not cause any relative movements of the first plug connector and the second plug connector with respect to one another. This can be achieved by connecting the connectors, in which the mutually engaging elements of the connectors are connected to one another with a clamping force. Such a clamping force can also be generated by a form-fit connection of the plug connectors.By means of such a closure, it is possible to completely separate the additive conveying assembly and the electronics assembly from one another. Complete disconnection also means here, in particular, that the electrical connection of the two assemblies is also separated from one another. This also allows, for example, the replacement of the electronic assembly or the additive conveying assembly.Furthermore, the device is advantageous if a supply connection for the liquid additive extends from the additive conveying assembly through the electronics assembly.For this purpose, the electronics assembly can have an opening or a passage through which the supply connection extends. The supply connection is preferably a connector to which a line for conducting the liquid additive from the device to a supply device (nozzle, injector, etc.) can be connected. It is particularly advantageous if the supply connection extends through the electronics assembly, because the electronics assembly is preferably arranged on the outside of a tank for the liquid additive. The additive delivery assembly is thus arranged in the tank for the liquid additive or between the tank for the liquid additive and the electronics assembly. The electronics assembly thus covers the additive delivery assembly with respect to the outside. It is therefore particularly advantageous to provide for the supply connection an opening or a passage in the electronics assembly, through which the supply connection extends when the electronics assembly and the additive conveying assembly are connected to one another. However, there is preferably nevertheless no contact between the liquid additive and the electronics assembly. The supply connection is preferably a line section which is fluid-tight sealed with respect to the electronics assembly through the electronics assembly.Furthermore, the device is advantageous if at least on the additive conveying assembly or on the electronics assembly a prevention means is provided, by means of which it is prevented that the electronics assembly and the additive conveying assembly can be connected to one another if the plug connection of the first plug connector and the second plug connector is not formed.Such a prevention means can ensure that the plug connection is formed in each case when the electronic assembly and the additive conveying assembly are connected to one another. In particular, it is prevented that the additive delivery assembly and the electronics assembly can be connected to one another if a correctly formed electrical plug connection is not established simultaneously. Such a prevention means can be designed, for example, as a lever element which flips over when the plug connection is formed and thereby releases a lock which has prevented the additive delivery assembly and the electronics assembly from being mounted before the plug connection was formed correctly.The invention is used in particular in a motor vehicle, having an internal combustion engine, an exhaust gas treatment device for purifying the exhaust gases of the internal combustion engine, a tank for a liquid additive and a device described here for conveying liquid additive from the tank into the exhaust gas treatment device. In the exhaust gas treatment device, an SCR catalyst is preferably provided, with which the method of selective catalytic reduction for cleaning the exhaust gases of the internal combustion engine is carried out. The liquid additive is preferably a reducing agent and particularly preferably a urea-water solution. This is supplied to the exhaust gas treatment device with the described device via a supply device. The supply device is connected to the device for conveying the liquid additive by a line for conducting the liquid additive. The supply device preferably comprises a nozzle for atomizing the liquid additive in the exhaust gas treatment device. The supply device preferably also comprises an injector for metering the liquid additive.The invention and the technical field are explained in more detail below with reference to the figures. The figures show particularly preferred exemplary embodiments, to which the invention is, however, not limited. In particular, it should be pointed out that the figures and in particular the size relationships illustrated are only schematic. The following are shown: FIG. 1 shows an embodiment variant of a described device, FIG. 2 : a motor vehicle, having a described device, FIG. 3 : shows a first variant embodiment of a described device before assembly, FIG. 4 : the device from FIG. 3 after assembly, FIG. 5 : the device from FIG. 3 after a first dismantling step, FIG. 6 : the device from FIG. 3 after a second dismantling step, FIG. 7 shows a second variant embodiment of a device described, FIG. 8 : shows a third embodiment variant of a described device, and FIG. 9 : a fourth embodiment variant of a described device.FIG. 1 shows a device 1 comprising an additive conveying assembly 2 and an electronics assembly 3. A pump 18, a valve 19 and a sensor 20 are provided here as hydraulic components 4. The sensor 20 can be, for example, a temperature sensor with which the temperature of the liquid additive can be measured. The sensor 20 can furthermore be a pressure sensor with which a pressure of the liquid additive can be determined. It is also possible for the sensor 20 to be a quality sensor with which a quality of the liquid additive can be measured. Individual or multiple sensors 20 can also be provided, which measure the quality, the pressure and / or the temperature of the liquid additive.The various hydraulic components 4 in the additive delivery assembly 2 are connected to one another via a delivery line 21. The liquid additive is conveyed along the conveying line 21 from an intake point 23 to a supply connection 24. A line can be connected to the supply connection 24, via which line the conveyed liquid additive can be passed on to a supply device, not shown here.The additive delivery assembly shown in FIG. 1 also has a return line 22, which can be opened and closed by the valve 19. The return line 22 also allows circulation of liquid additive from the intake point 23 by the pump 18 back into a tank. By the circulation delivery, air bubbles can be delivered out of the additive delivery assembly 2. The various hydraulic components 4 are connected to a first plug connector 6 via connections 5, which are illustrated in dashed lines.The electronics assembly 3 according to FIG. 1 has various electrical components 25, which are typically formed by semiconductor components. The electronic components 25 are connected to a second plug connector via connections 5. In this case, memory modules, processors, computing units, etc. can be provided as electrical components which, in particular, control, monitor, regulate the operation of the hydraulic components, and the like.The additive delivery assembly has a pot-shaped housing 9. The electronics assembly has a cover 10. The additive delivery assembly 2 and the electronics assembly 3 are mounted on one another in such a way that the first plug connector 6 and the second plug connector 7 form a plug connection 8. In addition, the lid 10 closes the pot-shaped housing 9, so that a dry interior space is formed in which the additive delivery assembly 2 and the electronics assembly 3 can be enclosed.FIG. 2 shows a motor vehicle 14, having an internal combustion engine 15 and an exhaust gas treatment device 16 for purifying the exhaust gases of the internal combustion engine 15. A liquid additive (preferably reducing agent and particularly preferably urea-water solution) can be supplied into the exhaust gas treatment device 16 by means of a supply device 26. For this purpose, the supply device 26 is supplied with liquid additive from a device 1 via a line 27. The liquid additive is stored in a tank 17 and can be removed from the tank 17 by means of the device 1.The tank 17 has a tank wall 28. The device 1 is arranged in the tank bottom 34 of the tank 17. It is shown here that a tank opening 33 is provided in the tank base 34, into which the device 1 is inserted. According to a further embodiment variant, it is also possible for the tank base 34 to have an inversion into a tank interior 35 of the tank 17, this inversion forming in the housing of the additive delivery assembly of the apparatus 1.FIGS. 3 to 6 show a preferred mode of operation of the first plug connector 6 and the second plug connector 7 in an embodiment variant of the device 1. The second plug connection 7 is formed on the electronics assembly 3. The first plug connection 6 is connected via movable connecting lines 12 to the hydraulic components, not shown here, in the additive delivery assembly 2. The additive delivery assembly 2 has a stop 11, which can preferably have a spring means 31, and which serves for firmly connecting the first plug connection 6 and the second plug connection 7. In FIG. 3, the additive conveying assembly 2 and the electronics assembly 3 of the device 1 can be seen before assembly. During assembly, the spring element 31 exerts a defined force on the first plug connector 6, by means of which the first plug connector 6 and the second plug connector 7 are pressed into one another.In FIG. 4, the additive conveying assembly 2 and the electronic assembly 3 are mounted to each other. The first plug connector 6 abuts the stop 11 and the second plug connector 7 is firmly connected to the first plug connector 6 during the assembly of the additive delivery assembly 2 and the electronics assembly 3 to form the plug connection 8.According to FIG. 5, during disassembly, the additive conveying assembly 2 and the electronics assembly 3 have been released from one another again. Nevertheless, the first plug connector 6 and the second plug connector 7 remain connected to one another as a plug connection 8. The first plug connector 6, which only loosely rests on the stop 11 with the spring element 31, has been released from the stop 11. However, the connection of the first plug connector 6 to the additive delivery assembly 2 continues via the connecting lines 12.According to FIG. 6, the plug connection 8 is again released. For this purpose, the first plug connector 6 has a closure 13. In FIG. 6, it is shown that the plug connection 8 can be detached from the first plug connector 6 and the second plug connector 7 when the closure 13 is actuated. The closure 13 is freely accessible when the electronic assembly 3 is already separated from the additive conveying assembly 2.FIGS. 7 to 9 show further embodiment variants of the device 1. FIG. 7 additionally shows a prevention means 29 by which it is possible to prevent the additive delivery assembly 2 and the electronics assembly 3 from being connected to one another when the plug connection of the first plug connector 6 and the second plug connector 7 is not formed. The preventing means 29 is formed as a half which is operated when the mating connection between the first connector 6 and the second connector 7 is properly formed. This lever must be actuated in order that the connection of the additive delivery assembly 2 and the electronics assembly 3 can take place. Otherwise, the lever prevents or at least obstructs the assembly of the additive delivery assembly 2 and the electronics assembly 3.FIG. 8 shows an embodiment variant of the device 1, in which the housing 9 of the additive conveying assembly 2 is a component of the tank wall 28 of a tank for the liquid additive. The tank or the section of the tank wall 28 shown here is preferably designed as an injection-molded component. The housing 9 forms, to a certain extent, an inversion in the tank wall 28, which extends into an interior of the tank, not shown here. Also shown is a suction point 23, through which a pump 18 in the additive delivery assembly 2 can remove the liquid additive directly from the tank.FIG. 9 shows an embodiment variant of the device 1, in which the supply connection 24 extends through an opening 32 in the electronics assembly 3.Even if technical details have been explained here in connection with an embodiment variant specifically shown in the figures, this does not mean that these details can only be realized with all other features of the embodiment variant shown. Rather, it should be true that all technical details of different embodiment variants of the figures can be interchanged / supplemented, in particular insofar as this is not technically excluded or the common use has been explicitly pointed out here.The invention described here makes it possible to produce a particularly cost-effective and advantageous device for conveying a liquid additive, in which electrical components of the device are clearly separated from hydraulic components of the device. This allows rapid assembly of the device. At the same time, good maintainability is obtained.List of reference characters1 Device 2 additive delivery assembly 3 electronics assembly 4 hydraulic component 5 connection 6 first plug connector 7 second plug connector 8 plug connector 9 pot-shaped housing 10 cover 11 stop 12 connection line 13 closure 14 motor vehicle 15 internal combustion engine 16 exhaust gas treatment device 17 tank 18 pump 19 valve 20 sensor 21 delivery line 22 return line 23 intake point 24 provision connection 25 electronic component 26 supply device 27 line 28 tank wall 29 prevention means 30 SCR catalytic converter 31 spring means 32 opening 33 tank opening 34 tank base 35 tank interior

Claims

Device (1) for conveying a liquid additive, comprising an additive conveying assembly (2) and an electronics assembly (3), wherein the additive conveying assembly (2) comprises at least one hydraulic component (4) for conveying the liquid additive, wherein all electrical connections (5) of the at least one hydraulic component (4) are led together in a first plug connector (6) on the additive conveying assembly (2), and wherein the electronics assembly (3) comprises a second plug connector (7) which can be connected to the first plug connector (6), wherein the first plug connector (6) and the second plug connector (7) are connected to one another and form a plug connection (8) when the electronics assembly (3) and the additive conveying assembly (2) are connected to one another, wherein the additive conveying assembly (2) has a pot-shaped housing (9) and the electronics assembly (3) has a cover (10) for the pot-shaped housing (9), and the pot-shaped housing (9) is closed by the cover (10) when the electronics assembly (3) and the additive conveying assembly (2) are connected to one another.Device (1) according to claim 1, wherein the pot-shaped housing (9) is part of a tank wall (28) of a tank (17) for the liquid additive.Device (1) according to one of the preceding patent claims, wherein at least the first plug connector (6) or the second plug connector (7) abut against a stop (11) when the electronics assembly (3) and the additive conveying assembly (2) are connected to one another, and wherein during the connection the first plug connector (6) and the second plug connector (7) are pressed into one another by means of the stop (11).Device (1) according to one of the preceding patent claims, wherein at least the first plug connector (6) or the second plug connector (7) have a movable electrical connection line (12), so that the first plug connector (6) or the second plug connector (7) remains connected when the electronics assembly (3) and the additive delivery assembly (2) are released from one another.Device (1) according to one of the preceding patent claims, wherein at least the first plug connector (6) or the second plug connector (7) have a closure (13) which can be activated in order to disconnect the plug connection (8).Device (1) according to one of the preceding patent claims, wherein a supply connection (24) for the liquid additive extends from the additive conveying assembly (2) through the electronics assembly (3).Device (1) according to one of the preceding patent claims, wherein at least on the additive conveying assembly (2) or on the electronics assembly (3) a connecting means (29) is provided, by means of which it is prevented that the electronics assembly (3) and the additive conveying assembly (2) can be connected to one another if the plug connection (8) of the first plug connector (6) and the second plug connector (7) is not formed.Motor vehicle (14), having an internal combustion engine (15), an exhaust gas treatment device (16) for cleaning the exhaust gases of the internal combustion engine, a tank (17) for a liquid additive and a device (1) according to one of the preceding patent claims for conveying liquid additive from the tank (17) into the exhaust gas treatment device (16).

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