Measuring device for detecting particles for use in a vehicle

Abstract

Measuring apparatus (10) for detecting particles for use in a vehicle (46) comprising a sensor element (36) with a measuring optic (38) designed to detect particles in a passing and flowing measuring current (30), characterized in that the measuring apparatus (10) has a vibration device (42) coupled to the measuring optic (38), such that when the vibration device (42) is activated, contaminants caused by the passing measuring current (30) on the measuring optic (38) can be removed by means of vibrations introduced by the vibration device (42).

Description

[0001] The invention relates to a measuring apparatus for detecting particles for use in a vehicle and to a vehicle having at least one such measuring apparatus.

[0002] The current debates about particulate matter levels in inner-city areas particularly affect the automotive industry. In Asia in particular, but also in Europe, particulate matter pollution in the ambient air is increasingly attracting public attention. As a result, lower-emission vehicles are increasingly in demand among a broader customer group. However, additional new customer requirements are also emerging. Particularly in very large metropolitan areas with correspondingly high traffic density, customers want to be able to measure current particulate matter pollution at any time, even while on the move, for example, in the vehicle itself. Publicly known sensor concepts use a fan in the sensor housing to create a vacuum, and ambient air is drawn into the interior through an air inlet with integrated coarse particle separation.There, the air flow is guided past a measuring chamber equipped with laser optics, which determines the particle count based on the resulting reflections. The measured air flow is then expelled from the sensor housing through the outlet opening. The challenge with this measurement method is the fact that a contaminated media flow is to be measured, but the optical measuring device must not become contaminated in order to ensure reliable measurements at all times. Alternative concepts for measuring particles are known from the state of the art. One such solution is presented below.

[0003] A measuring arrangement and a method for directing and detecting particles are known from the document DE 10 2016 215 419 A1. Such a measuring arrangement comprises an electrostatic concentrator, a surface, and an imaging sensor configured to detect particles. In particular, the measuring arrangement comprises the following features: an electrostatic concentrator designed to direct particles to be detected toward a surface, an imaging sensor designed to detect the particles directed toward the surface, wherein the electrostatic concentrator has a field electrode arranged in the surface, on the surface, or adjacent to the surface and designed to generate an inhomogeneous electrostatic field to direct the particles to be detected toward the surface. A method is also disclosed.The method is intended for detecting particles and comprises the following steps: directing particles to be detected towards a surface by means of an electrostatic concentrator, detecting the particles directed onto the surface and in a resting state by means of an imaging sensor, wherein the electrostatic concentrator has a field electrode which is arranged in the surface or on the surface or adjacent to the surface and generates an inhomogeneous electrostatic field in order to direct the particles to be detected towards the surface.

[0004] In addition, a method known from the prior art, known as the "Shield Air" principle, provides for a second air stream enveloping the actual measuring air stream in addition to the actual measuring air stream. In this method, a second air stream is generated in addition to the actual measuring air stream, which is first filtered and then merged with the first air stream in such a way that it envelops it and is guided past a laser measuring chamber. In this way, the particle-laden air stream can be measured without contaminating the sensitive measuring optics. While the effectiveness of the "Shield Air" concept is undisputed, the implementation of the second air path in the sensor requires considerably more space. With this increased space requirement, the associated additional material costs can also be considered a disadvantage.While solutions are known in this context, some of which attempt to achieve this solely through coarse particle separation at the sensor inlet, high dust loads result in the laser optics of the measuring chamber becoming increasingly contaminated, and the required measurement accuracy can no longer be achieved.

[0005] WO 2011 / 076 265 A1 describes an arrangement and a method for measuring pourable products, such as cereal grains, using an electrostatic concentrator and an NIR measuring probe.

[0006] US 2013 / 0 192 341 A1 discloses a smoke detector in which particles of the measuring current are also electrostatically deposited on a measuring surface and measured.

[0007] DE 10 2017 220 252 A1 discloses an optical device for motor vehicles, for example, a headlight, an exterior camera, or a sensor. Contamination of a transparent or translucent pane of the optical device is to be removed by continuously or periodically moving the pane with a drive means.

[0008] The invention is based on the object of providing a measuring apparatus for detecting particles for use in a vehicle, which on the one hand enables a permanently high measurement accuracy and on the other hand requires less installation space and is cost-effective.

[0009] According to the invention, a measuring apparatus for detecting particles is provided for use in a vehicle. Such a measuring apparatus comprises a sensor element with measuring optics, which are designed to detect particles in a passing and flowing measuring current, wherein the measuring apparatus has a vibration device coupled to the measuring optics, such that when the vibration device is activated, contamination on the measuring optics caused by the passing measuring current can be removed by means of vibrations introduced by the vibration device. In this way, it is possible to cost-effectively remove disruptive contamination from the measuring optics. The vibration device can be designed such that only a manageable installation space is required. In particular, the installation space can thus be designed to be smaller than with a concept with an additional air flow.Contamination caused by the passing measuring stream can include all forms of particles and other dirt residues present in the measuring stream consisting of introduced air. If this contaminant deposits on the sensitive measuring optics, reliable and accurate measurement of particles, especially fine dust particles, in the measuring stream is no longer possible or only possible to a very limited extent. In this respect, the measuring device presented represents a special sensor concept that shows little or no influence on measuring accuracy even after long-term exposure to high particle concentrations in the measuring stream. In this respect, the measuring device presented ensures consistently high measuring accuracy, while requiring little installation space and being able to be manufactured and operated at reduced costs.

[0010] In a further preferred embodiment of the invention, it is provided that a vehicle is provided with at least one measuring device according to claims 1 to 9. The aforementioned advantages also apply to the presented vehicle, as far as transferable.

[0011] Further preferred embodiments of the invention emerge from the remaining features mentioned in the subclaims.

[0012] Thus, in a further preferred embodiment of the invention, the measuring optics are arranged in the sensor element in such a way that the direction of fall of the contaminants after exposure to vibrations is aligned in the direction of gravity, and wherein the flow direction of the measuring current is also aligned in the direction of gravity. This ensures that contaminants, for example in the form of particles that have undesirably deposited on the measuring optics, can be mobilized after exposure to vibrations in such a way that they do not remain on the measuring optics or in the immediate vicinity of the measuring optics. Rather, they fall away from the measuring optics in the direction of gravity, with the measuring current guided past further supporting this direction of movement of the mobilized contaminants or particles, at least in the areas in which the measuring current is guided directly past the measuring optics.In other words, the installation position of the sensor element with a measuring optics is selected in such a way that the particles can be released after or during the vibration excitation and thus removed from the measuring optics in the direction of gravity.

[0013] In a further preferred embodiment of the invention, the vibration device comprises at least one ultrasonic actuator. Ultrasonic actuators can be used to initiate vibrations particularly reliably, thus providing a particularly efficient measuring device with a small installation space and an overall cost-effective approach.

[0014] Furthermore, in a further preferred embodiment of the invention, the vibration device comprises at least one ventilation motor from a fan device of the measuring apparatus. The ventilation motor of the measuring apparatus is used as the vibration source. For this purpose, the motor can be switched on and off briefly in such a way that it generates vibration but does not convey any volume flow. In this way, further costs can be saved because no additional components are required. Furthermore, no further installation space is required for additional and more complex components, resulting in a compact measuring apparatus which nevertheless ensures reliable, long-term operation. Since the ventilation motor is already provided in the apparatus, the required vibration or vibrations can be cleverly generated using a user-defined routine.This also allows for convenient, user-defined interval-based application. These vibrations can then be ultimately transmitted to the desired position of the measuring optics either directly or by means of simple transmission components that do not require a separate technical concept.

[0015] Furthermore, a further preferred embodiment of the invention provides that the vibrations introduced by the vibration device are intended for a user-defined duration, in particular for a time interval of 0.5 to 3 seconds, in particular for 1 second. A short, defined time interval is sufficient, on the one hand, to free the measuring optics of unwanted contamination, for example, in the form of particles, and, on the other hand, the measuring process is not disrupted for an unnecessarily long period of time. This also prevents the measuring optics from being subjected to mechanical stress for an unnecessarily long period of time.

[0016] In a further preferred embodiment of the invention, the vibration device comprises a one-sided holder element which is coupled to at least one vibrating structure of the vehicle, such that vibrations from the vibrating structure of the vehicle can be transmitted to the measuring optics by means of the holder element. Thus, a very simple construction concept ensures a compact design of the presented measuring apparatus. Vibrating structures of the vehicle can be represented by any components which exhibit sufficient vibrations, for example during the usage phase of the vehicle, so that these can then be transmitted accordingly. The holder element can, for example, be connected to these vibrating structures in a user-defined manner, such that the holder element continues to vibrate for a certain period of time.Even a simple contact could be sufficient to at least partially transfer the vibrations from the vehicle's vibrating structures to the measuring optics, so that any contaminants interfering with the measuring optics can be loosened and thus removed. In other words, the measuring device presented here is designed so that it can be arranged in a vehicle in such a way that, due to its construction, it is exposed to a higher vibration load. This can be achieved, for example, by a design providing a one-sided holder concept that continues to vibrate for a certain period of time after a mechanical excitation. The mechanical excitation can originate, for example, from any vibrating structures or components of the vehicle, whereby the vibrations can be transmitted directly and / or indirectly.

[0017] Furthermore, a further preferred embodiment of the invention provides for the measuring current to be branched off from a main current. This makes it possible to guide a defined volume past the measuring optics in a user-defined manner, corresponding to a respective sensor element with a respective measuring optic, thus ensuring a reliable measuring process.

[0018] Furthermore, in a further preferred embodiment of the invention, the main flow can be introduced into the measuring apparatus by means of the at least one ventilation motor from a fan device via an air inlet element with a coarse particle device, so that the measuring flow comprises pre-cleaned air. This ensures that contaminants present in the measuring flow do not comprise larger components such as coarse particles, so that these cannot cause damage to the measuring optics. Furthermore, as already mentioned, the ventilation motor can assume an additional function, enabling a compact design of the apparatus. Furthermore, the dimensions and design of the coarse particle device can be selected depending on the location of use.The coarse particle device can also be provided in an interchangeable manner in the measuring device so that it can be replaced accordingly, for example, when a maximum contamination rate is reached.

[0019] Finally, in a further preferred embodiment of the invention, it is provided that the measuring current and the main current can be discharged from the measuring device via separate air outlets, wherein the measuring current and the main current are separated from one another by means of a circuit board. This separation by means of the circuit board is to be understood in such a way that the separation can also be provided at least partially. In other words, the circuit board can at least partially separate the two currents, and other components, such as an outer housing element, can also be provided to limit the currents. Such a circuit board can be designed in such a way that any components of the measuring device can be arranged on or in it. For example, any form of vibration device could be coupled or connected to the circuit board in such a way that the provided measuring optics can be subjected to vibrations.One or more sensor elements with corresponding measuring optics or measuring instruments could also be arranged on this separating circuit board. This allows for an even more compact design of the measuring device, which can thus be manufactured cost-effectively.

[0020] The various embodiments of the invention mentioned in this application can be advantageously combined with one another, unless otherwise stated in the individual case.

[0021] The invention is explained below in exemplary embodiments with reference to the accompanying drawings. They show: Fig. 1 is a schematic sectional view of a measuring apparatus for detecting particles for use in a vehicle; Fig. 2 a schematic representation of a vehicle with a measuring device.

[0022] Fig. 1 shows a schematic sectional view of a measuring device 10 for detecting particles for use in a vehicle 46. In the illustrated embodiment, the measuring device 10 has a substantially rectangular basic shape and comprises a housing element 12. In the housing element 12, an air inlet element 14 is schematically shown on the lower right side of the image plane, which serves as an inlet for a main flow 16.

[0023] The air inlet element 14 also includes a coarse particle device 18, which filters out coarser contaminants from an air volume entering from outside, so that the main flow 16 already consists of a pre-filtered air volume. The main flow 16 is directed over or through a substantially rectangular tube system 19. A fan device 20 is shown for this purpose just downstream of the air inlet element 14.

[0024] This fan device 20 comprises a ventilation motor 22, which can, for example, be an electric motor designed according to the size of the measuring device 10. An inner boundary wall 24 is represented by a circuit board 26 installed essentially centrally in the measuring device 10. The circuit board 26 protrudes (relative to the image plane) vertically over the entire interior 28 of the housing element 12 and is depicted with a substantially rectangular basic shape. In the upper area (relative to the image plane), the circuit board 26 is interrupted, so that a measuring current 30, which is branched off from the main current 16, is introduced into a measuring section 32.

[0025] In other words, the circuit board has an opening area 34 through which the measuring current 30 can be conducted, so that it can be guided over the measuring section 32 within the measuring device 10. A main flow air outlet element 35 is shown opposite the opening area 34. The main flow air outlet element 35 can, as shown, simply be an opening in the housing element 12. The measuring section 32 is shown as an angled tube, wherein a diameter of the measuring section 32 is smaller than a diameter of the tube system 19 through which the main flow 16 is conducted. The measuring current 30 is deflected on the measuring section 32 in such a way that ultimately a longer section or a partial section of the measuring section 32 is set essentially perpendicular to the direction of gravity.

[0026] In the Fig. 1, a sensor element 36 is shown halfway along this essentially vertical section. The sensor element 36 is shown with a measuring optics 38 arranged on the circuit board 26. For example, the measuring optics 38 can be detachably attached to the circuit board 26. It is conceivable, for example, that fastening means (not shown in detail) are provided for this purpose, which, for example, also enable fine adjustment of the measuring optics. The measuring optics 38 can, for example, comprise a laser light source with a particle counter. In addition, a beam trap element 40 associated with the measuring optics 38 is arranged on the opposite side of the measuring section 32. In this respect, the essentially vertically oriented section of the measuring section 32 runs between the measuring optics 38 and the associated beam trap element 40.

[0027] In other words, the measuring optics 38 and an associated component, for example in the form of the beam trap element 40, are arranged or attached to opposite side regions of the measuring section 32, such that a measuring current 30 to be measured runs or is conducted essentially centrally between the measuring optics 38 and the associated component (for example in the form of the beam trap element 40). A vibration device 42 is also arranged on the circuit board 26 at the height at which the measuring optics 38 is arranged. This vibration device 42 can, for example, comprise one or more ultrasonic actuators.

[0028] It is also conceivable that this vibration device 42, in a variant not shown in detail, is coupled to the fan device 20 by means of the ventilation motor 22, so that vibrations from the ventilation motor 22 can be at least partially transmitted to the vibration device 42. Generally, the vibration device 42 is also arranged such that, upon activation of the vibration device 42, contaminants on the measuring optics 38 caused by the passing measuring current 30 can be removed by the vibrations introduced by the vibration device 42. This contaminant can, for example, be any form of dust and / or particles, wherein the particles can in particular be fine dust particles. The loosened contaminants fall away from the measuring optics 38 essentially vertically in the direction of gravity.As soon as these contaminants have detached themselves from the measuring optics 38, they fall away from the measuring optics 38, with the falling direction of these detached contaminants being provided essentially parallel to the direction of the measuring current 30. The measuring current 30 exits the measuring device 10 at the end of the measuring section 32 at a measuring current air outlet element 44, or is guided and directed in such a way that this air volume from the measuring current 30 can leave the measuring device 10 again. The measuring current air outlet element 44 can, as shown, simply be an opening in the housing element 12.

[0029] Fig. 2 shows a schematic representation of a vehicle 46 with a measuring device 10. List of reference symbols 10 Measuring device 12 Housing element 14 Air inlet element 16 Main stream 18 Coarse particle device 19 tube system 20 Fan device 22 Ventilation motor 24 Boundary wall 26 circuit boards 28 Interior 30 measuring current 32 measuring sections 34 Opening area 35 Main flow air outlet element 36 Sensor element 38 measuring optics 40 radiation trap element 42 Vibration device 44 Measuring current air outlet element 46 vehicles

Claims

[1] Measuring apparatus (10) for detecting particles for use in a vehicle (46) comprising a sensor element (36) with a measuring optics (38) which is designed to detect particles in a passing and flowing measuring stream (30), characterized by that the measuring apparatus (10) has a vibration device (42) coupled to the measuring optics (38), so that when the vibration device (42) is activated, contamination on the measuring optics (38) caused by the passing measuring current (30) can be removed by means of vibrations introduced by the vibration device (42). [2] Measuring apparatus (10) according to claim 1, wherein the measuring optics (38) are arranged in the sensor element (36) in such a way that a falling direction of the contaminants after exposure to vibrations is aligned in the direction of gravity and wherein a flow direction of the measuring stream (30) is also aligned in the direction of gravity. [3] Measuring apparatus (10) according to one of the preceding claims, wherein the vibration device (42) comprises at least one ultrasonic actuator. [4] Measuring apparatus (10) according to one of the preceding claims 1 to 2, wherein the vibration device (42) comprises at least one ventilation motor (22) of a fan device (20) of the measuring apparatus (10). [5] Measuring apparatus (10) according to one of the preceding claims, wherein the vibrations introduced by the vibration device (42) are provided for a user-defined time period, in particular for a time interval of 0.5 to 5 seconds, in particular for 1 second. [6] Measuring apparatus (10) according to one of the preceding claims 1 to 2, wherein the vibration device (42) comprises a one-sided holder element which is coupled to at least one vibrating structure of the vehicle (46) such that vibrations from the vibrating structure of the vehicle (46) can be transmitted to the measuring optics (38) by means of the holder element. [7] Measuring apparatus (10) according to one of the preceding claims, wherein the measuring current (30) can be branched off from a main current (16). [8] Measuring apparatus (10) according to claims 4 and 7, wherein the main flow (16) can be introduced into the measuring apparatus (10) by means of the at least one ventilation motor (22) from the fan device (20) via an air inlet element (14) with a coarse particle device (18), so that the measuring flow (30) comprises pre-cleaned air. [9] Measuring apparatus (10) according to one of claims 7 or 8, wherein the measuring current (30) and the main current (16) can be discharged from the measuring apparatus (10) via separate air outlets, wherein the measuring current (30) and the main current (16) are separated from one another by means of a circuit board (26). [10] Vehicle (46) with at least one measuring apparatus (10) according to one of claims 1 to 9.

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