Sensor device for checking at least one gas volume

Abstract

The invention relates to a sensor device for checking at least one gas volume, in particular for detecting fine dust in at least one gas volume, the sensor device comprising at least one measuring space for accommodating the gas volume, at least one sample gas inlet associated with the measuring space, at least one sample gas outlet associated with the measuring space, and at least one housing, wherein the measuring space, the sample gas inlet and the sample gas outlet are at least partially arranged in a first space of the housing, the invention essentially providing that at least one further gas inlet is associated with the measuring space, and at least one pressure equalization element is arranged between the first housing space and the further gas inlet. The invention also relates to a motor vehicle having a sensor device according to the invention.

Description

Technical Field

[0001] The present invention relates to a sensor device for detecting fine dust in at least one gas volume, comprising at least one measuring space for accommodating the gas volume, at least one sample gas inlet assigned to the measuring space, at least one sample gas outlet assigned to the measuring space and at least one housing, wherein the measuring space, the sample gas inlet and the sample gas outlet are at least partially arranged in a first housing space of the housing. Background Art

[0002] The sensor device for checking gas volume, especially for detecting fine dust, is used in various application fields, for example, in the automotive field. For example, the fine dust content of the sample gas volume can be checked by the sensor device. For this reason, the sensor device has at least one measuring space, in which the sample gas volume can be checked. For example, the fine dust content of the vehicle ambient air as the sample gas can be checked, so as to judge whether the ventilation of the vehicle interior space with ambient air is meaningful, for example. The sample gas volume can be input to the measuring space in the form of a gas flow, especially through a sample gas input pipeline, through a sample gas input part. After analysis, the sample gas volume can be derived from the measuring space through a sample gas output part. The measuring space, the sample gas input part and the sample gas output part are at least partially arranged in a housing. For example, a laser source can be used to measure the sample gas volume in the transmission measuring space. Based on the reflection and scattering of the incident laser, the fine dust contained in the sample volume can be inferred. When the sensor device is used in the automotive field, the sensor device may be subjected to severe temperature fluctuations. In the event of temperature fluctuations, in particular when the measuring chamber is arranged in a closed housing, an overpressure may occur in the housing, for example, which may lead to a cracking of the housing or may also adversely affect the measurement.

[0003] In order to compensate for fluctuations in the internal pressure in the housing, which are caused, for example, by temperature fluctuations, the housing can have a pressure compensation element relative to the surroundings of the housing. For example, the pressure compensation element can be formed in the outer housing wall via a pressure compensation opening. When the sensor device is used in the automotive sector, the pressure compensation opening must be protected, for example, against the ingress of dirt particles. For this purpose, filters or covering elements provided for this purpose are required, wherein complete protection, in particular protection against external influences, is very complex. Summary of the invention

[0004] The object of the present invention is to specify a sensor device in which a pressure equalization between the interior of the housing and the surroundings is possible, wherein the penetration of dirt particles into the housing is prevented.

[0005] In a sensor device for checking at least one gas volume, in particular for detecting fine dust in at least one gas volume, the sensor device comprises at least one measuring space for accommodating the gas volume, at least one sample gas inlet assigned to the measuring space, at least one sample gas outlet assigned to the measuring space and at least one housing, wherein the measuring space, the sample gas inlet and the sample gas outlet are at least partially arranged in a first space of the housing, and the present invention basically provides that at least one further gas inlet is assigned to the measuring space and at least one pressure equalization element is arranged between the first housing space and the further gas inlet.

[0006] The measuring space is arranged in the first housing space of the housing, and the sample gas volume to be measured is contained in the measuring space or the sample gas flow is guided through the measuring space. A sensor device is assigned to the measuring space, and the sensor device has, for example, a laser source and a sensor element, in particular a photodiode. The sample gas, i.e., the gas or gas mixture to be tested, present in the measuring space is irradiated with laser light by the laser source, wherein the laser light scattered on the dust particles in the sample gas volume can be detected by means of the photodiode. In order to input the sample gas, in particular, the ambient air, in the form of a sample gas flow, the sensor device has a sample gas input as follows, which can be constructed by an input pipeline, for example. Accordingly, a sample gas output for outputting the analyzed sample gas is assigned to the measuring space, which can be constructed by an output pipeline. In addition, another gas input is assigned to the measuring space. This other gas input can, for example, refer to a purge gas input, i.e., an encapsulated gas input, through which the purified gas can be introduced into the measuring space, so as to prevent the measuring space, the optical element, etc., from being contaminated, for example, due to the deposition of fine dust particles. The purge gas input part can be partially configured as a pipeline for guiding gas, in particular as a pipeline and can be at least partially arranged in the second housing space of the housing. A pressure balancing element is arranged between the first housing space and the other gas input part, which connects the first housing space to the other gas input part. The overpressure generated in the first housing space, for example due to temperature fluctuations, can be balanced by the pressure balancing element. Here, pressure balance occurs between the other gas input part and the first housing space. Therefore, the overpressure established inside the first housing space can be reduced by the other gas input part. Therefore, there is only an indirect connection between the interior space of the housing and the environment. Therefore, a direct connection between the interior of the housing and the environment is not necessary. Thus, dirt particles are prevented from entering through a direct connection to the environment.

[0007] In a further development of the invention, the housing is hermetically sealed. The hermetically sealed housing, in particular the first housing space, provides good protection for the components located in the housing, in addition to the first housing space in which the measuring space is arranged. Thus, the fine dust content can be measured accurately without influencing external effects. By arranging a pressure equalization element inside the housing between the first housing space and the gas line, an accurate measurement can be performed even in the event of pressure fluctuations, without requiring a direct connection to the environment.

[0008] In a further development of the invention, the pressure equalization element is designed as a pressure equalization opening between the first housing space and the further gas inlet. The pressure equalization element between the first housing space and the further gas inlet can be designed as a pressure equalization opening. The pressure equalization opening connecting the first housing space to the further gas inlet provides a simple possibility for equalizing the overpressure that builds up in the first housing space.

[0009] In a modified version of the present invention, the other gas input part refers to the purge gas input part. The purge gas input part can be provided to the measuring space, through which the purge gas, for example, the sample gas that has been tested in the measuring space, can be removed from the particles carried therein and introduced into the measuring space to prevent or remove the optical elements in the measuring space from being contaminated by the deposition of particles. In particular, the purge gas input part can be partially constructed as a pipeline and have a connection part for guiding gas with the sample gas output part. The gas flow part of the sample gas flow that has been tested and introduced into the sample gas output part from the measuring space is branched out from the sample gas output part and input to the purge gas input part. For this purpose, the purge gas input part can be connected to the sample gas output part, for example, by a T-piece. The purge gas input part can have a purification device, for example, a filter device with at least one filter element, through which the sample gas that has been tested is filtered and thus removed from the particles in the sample gas. The filtered sample gas can be input into the measuring space in this way so that the gas flow of the purified sample gas flows through the optical elements located in the measuring space, thereby achieving a purification effect. In particular, a pressure equalization element can be arranged between the purge gas inlet and the first housing space, so that an overpressure that builds up in the first housing space can be reduced via the pressure equalization element into the purge gas inlet. Since the purge gas inlet has a connection to the gas-conducting chamber and indirectly via the sample gas outlet has a gas-conducting connection to the environment, the overpressure in the housing can be equalized via the purge gas inlet without requiring a direct connection to the environment.

[0010] In a refinement of the present invention, a planar filter element is assigned to the clean gas input, and a section of the planar filter element is assigned to the pressure balance element. A planar filter element, such as a filter membrane, is assigned to the clean gas input. Particles contained in the gas guided in the clean gas input are filtered out by the filter element. For example, the sample gas that has been tested can be processed by one or more filter stages in the clean gas input so as to use the purified sample gas as the clean gas. A section of the filter element of the clean gas input is assigned to the pressure balance element. By making the filter element assigned to the pressure balance element, especially to the pressure balance opening, foreign matter, such as dust particles from the gas guided in the clean gas input, is prevented from entering the first housing space through the pressure balance opening. The filter element is thus used on the one hand to filter the sample gas, wherein the sample gas that has not been purified passes through the filter in the flow direction when it is introduced into the measurement space. On the other hand, the filter section assigned to the pressure balance element is used to protect the first housing space from contamination and pass in the opposite direction of the flow direction of the clean gas input under the pressure balance of the overpressure in the first housing space. By using a filter element for the pressure equalization opening and for the purified gas inlet, costs are saved during production by not having to provide an additional filter element for the pressure equalization opening.

[0011] In a further development of the invention, the filter section assigned to the pressure equalization element is spatially separated from the filter region assigned to the purge gas inlet. By spatially separating the filter region assigned to the pressure equalization opening and the filter section assigned to the purge gas inlet, the possibility of the filter section of the pressure equalization element being covered with particles of the gas to be purified from the purge gas inlet and thus being contaminated is eliminated. As a result, long-term permeability of the filter of the pressure equalization opening is achieved.

[0012] In a further development of the invention, the edge of the pressure equalization opening is connected to the filter element. The edge of the pressure equalization opening is connected to the filter element which is designed in a planar manner. By connecting the edge to the filter element, a spatial separation of the filter section provided for the clean gas inlet and the filter section provided for the pressure equalization element is achieved in a simple manner.

[0013] In a further development of the invention, the edge of the pressure equalization opening is welded to the filter element. By welding the edge of the pressure equalization opening to the flat filter element, which can be, for example, a nonwoven filter fabric, a simple connection is achieved. By welding the edge of the pressure equalization opening, a spatial separation is formed between the two filter sections.

[0014] Another aspect relates to a vehicle, in particular a motor vehicle, having a sensor device according to the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention will be further described below with reference to the exemplary embodiments shown in the accompanying drawings.

[0016] Figure 1 A sensor arrangement for checking the gas volume is shown schematically, and

[0017] Figure 2 A filter element with a filter section is shown schematically. DETAILED DESCRIPTION

[0018] exist Figure 1, a sensor device 1 for checking at least one sample gas volume or sample gas flow is shown, the sensor device having a measuring space 2, a sample gas input 3, a sample gas output 4 and a purge gas input 5. The sensor device 1 has a measuring space 2 in which the sample gas volume, for example, the air volume from the vehicle environment, can be checked. For this purpose, optical elements 6, 7 are arranged in the measuring space 2, such as, for example, a laser source and a corresponding laser receiving device, such as a photodiode. The sample gas to be checked is introduced into the measuring space 2 via the sample gas input 3. For this purpose, the sensor device 1 has a ventilation unit 8 through which the sample gas can be sucked. The sample gas output 4 is led out of the ventilation unit 8, through which the checked sample gas can be discharged back into the environment. A purge gas input 5 is arranged starting from the sample gas output 4. For example, the pipelines of the sample gas output 4 and the purge gas input 5 can be connected to each other by a T-piece 9. The purge gas input 5 has a purification device, in particular a filter device with a filter element 10, by which the sample gas to be tested can be filtered and particles in the sample gas can thus be purified. By the purification carried out in the filter device, the sample gas can be used as purge gas for the measurement space 2. For this purpose, the purge gas input 5 is connected to the measurement space 2 via two gas inlets 11, 12. The gas inlets 11, 12 are arranged in the region of the optical elements 6, 7 so that the purge gas from the purge gas input 5 is guided along the optical elements 6, 7. In particular, the purge gas flow is guided along the optical elements 6, 7 so that the purge gas flow is guided between the optical elements 6, 7 and the sample gas flow. Therefore, the purge gas flow forms an enveloping air flow that envelops the sample gas flow, which acts like a protective layer and protects the optical elements 6, 7 from contamination by particles of the sample gas flow. The size of the volume fraction of the tested sample gas branched from the sample gas outlet 4 into the purge gas inlet 5 can be adjusted by a flow control device 13, which is arranged in the region of the gas outlet 14 of the sample gas outlet 4. The smaller the flow rate of the sample gas through the gas outlet 14 is set, the higher the volume fraction of the sample gas branched into the purge gas inlet 5 used as a bypass. The intensity of the purge gas flow can therefore be controlled by the flow control device 13.

[0019] The sensor device 1 has a housing 15. The measuring space 2 and the sample gas input 3 are arranged in a first housing space 16. A pressure equalization element 17 configured as a pressure equalization opening is arranged between the first housing space 16 and the purge gas input 4. For example, temperature fluctuations may cause pressure changes in the first housing space 16, which may, for example, cause the housing to crack. The overpressure established in the first housing space 16 can be equalized by the pressure equalization element 17, for example, via the purge gas input 5. Therefore, a direct connection between the first housing space 16 and the environment of the housing 15 is not required, thereby excluding the entry of dirt from the environment of the housing 15. The filter element section 18 of the filter element 10 is assigned to the pressure equalization element 17. The filter element section 18 is separated from the area assigned to the purge gas input 5 by a spatial separation 19. The pressure equalization element 17 and thus the first housing space 16 are protected by the filter element section 18 from the entry of contaminant particles from the gas to be purified.

[0020] exist Figure 2 1 shows a pressure equalization element 17 which is designed as a pressure equalization opening and has a filter element 10 and a filter element section 18. In order to purify the gas guided in the purge gas inlet 5, the purge gas inlet 5 has a filter device with a filter element 10 which is designed in a planar manner. The filter element section 18 of the filter element 10 is assigned to the pressure equalization element 17, wherein the filter element section 18 is spatially separated from the region of the filter element 10 for purifying the sample gas. The spatial separation 19 of the filter element section 18 is produced by the circumferential welding of the edge 20 of the pressure equalization element and the filter element 10. The spatial separation 19 prevents the filter element section 18 assigned to the pressure equalization element 17 from being loaded by the gas guided in the purge gas inlet 5.

[0021] Therefore, the disclosure of the present invention is not limited to the described or claimed feature combinations, but rather all feature combinations that make sense within the scope of the present invention are considered to be disclosed.

Claims

1. A sensor device for testing at least one gas volume or for detecting fine dust in at least one gas volume, the sensor device comprising at least one measuring space (2) for accommodating the gas volume, at least one sample gas inlet (3) assigned to the measuring space (2), at least one sample gas outlet (4) assigned to the measuring space (2) and at least one housing (15), wherein: The measuring space (2), the sample gas inlet (3) and the sample gas outlet (4) are at least partially arranged in a first housing space of the housing (15). It is characterized in that At least one further gas inlet is associated with the measuring space (2), and At least one pressure equalization element is arranged between the first housing space (16) and the further gas inlet. The further gas inlet is a purge gas inlet (5), through which purified gas can be introduced into the measuring space (2), wherein the purge gas inlet (5) can be partially constructed as a gas-conducting pipeline and can be at least partially arranged in a second housing space of the housing (15), The purge gas inlet (5) has a gas-conducting connection to the sample gas outlet (4), wherein a gas flow portion of a tested sample gas flow introduced from the measurement space (2) into the sample gas outlet (4) branches off from the sample gas outlet (4) and is input to the purge gas inlet (5).

2. The sensor device according to claim 1, characterized in that The housing (15) is closed in a gas-tight manner.

3. The sensor device according to claim 1, characterized in that The pressure equalization element (17) is designed as a pressure equalization opening between the first housing space (16) and the further gas inlet.

4. The sensor device according to claim 3, characterized in that A flat filter element (10) is assigned to the clean gas inlet (5), and a filter section of the flat filter element (10) is assigned to the pressure equalization element (17).

5. The sensor device according to claim 4, characterized in that The filter section associated with the pressure equalization element (17) is spatially separated from the filter region associated with the clean gas inlet (5).

6. The sensor device according to claim 5, characterized in that The edge (20) of the pressure equalization opening is connected to the filter element (10).

7. The sensor device according to claim 5 or 6, characterized in that The edge (20) of the pressure equalization opening is welded to the filter element (10). 8 . A motor vehicle comprising a sensor device ( 1 ) according to claim 1 .

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