EP3963899B1 - Device and system for measuring the sound volumes of noises of a road vehicle in road traffic - Google Patents

Description

The invention relates to a device and a system for measuring the volume of noise from a road vehicle in traffic.

Noise pollution, for example at early and/or late hours or at night, is a major annoyance for many roadside residents. According to statistics, traffic noise is the second most important form of environmental pollution after air pollution. Traffic noise can increase the risk of heart disease and/or diabetes for those affected. Speed measurement systems and speed limits are known measures against noise pollution.

Devices for measuring the volume of noise from a road vehicle in traffic are from the prior art U.S. 2019/082256 A1 , U.S. 3,661,224 A and JP H03 113700 A known. U.S. 2019/082256 A1 describes the features mentioned in the preamble of claim 1. The documents JP 2004 312156 A , U.S. 2005/220448 A1 , EP 2 566 182 A1 , U.S. 2013/251183 A1 and U.S. 2013/083957 A1 show measures to protect against contamination in an acoustic sensor.

This is where the invention comes in. The object of the invention was to improve the measures against noise pollution in road traffic.

The following definitions and further explanations apply to the entire subject matter of the invention.

The device according to the invention measures the volume of noise from a road vehicle in traffic. The device solves the task through system properties from the specific matching of individual components of the device to one another. The device includes an acoustic sensor. Furthermore, the device includes protective grids to protect the device against the ingress of coarser foreign bodies. The protective grille comprises at least one opening for admitting airborne sound into the device. The opening is arranged axially offset to an axial axis of the device. In addition, the device includes a flow bypass. The flow bypass runs between the protective grille and the acoustic sensor. In this way, fluids and/or foreign bodies that have entered the device due to air currents are guided away from the acoustic sensor and out of the device. Furthermore, the device comprises a sound channel arranged parallel to the axial axis, at the first end of which, in the air flow direction, the protective grille is arranged and at the second end of which the acoustic sensor is arranged is. The diameter, length, volume, shape and/or material properties of the sound channel are adapted in order to dampen the device's natural modes. The device also includes a printed circuit board. The printed circuit board includes components and their connections for pre-processing analog or digital signals from the acoustic sensor. The components are designed for analog or digital signal processing and/or for implementing filter functions, phase reversal functions, compressor functions and/or amplifier functions. Furthermore, the printed circuit board includes the acoustic sensor on one side of the printed circuit board. For example, the acoustic sensor is arranged on the rear side of the printed circuit board in the air flow direction. In this case, the acoustic sensor has its sound entry opening on the component mounting side of the printed circuit board, and the printed circuit board includes a printed circuit board opening for the sound entry. Alternatively, the acoustic sensor is arranged on the front side of the printed circuit board in the air flow direction. In this case, the acoustic sensor has its sound entry opening on the side of the acoustic sensor opposite the component mounting side of the printed circuit board. The circuit board also includes a computing unit. The arithmetic unit is designed to generate a control signal for a detection unit as a function of signals from the acoustic sensor when it is detected that a target volume has been exceeded. The road vehicle is thus detected. Furthermore, the device includes an interface to provide the control signal of the detection unit.

The invention provides a device that detects the volume of passing road vehicles and the road vehicle can flash when a limit value is exceeded, similar to a speed monitoring system. The special feature of the device according to the invention is the functionality and airborne sound detection and its conversion under difficult environmental and flow conditions that exist in road traffic. These environmental conditions also result from the intended use and/or installation locations of the device in road traffic, where relative air currents arise. Using the device according to the invention, airborne noise can be detected and converted into electrical signals in a temperature range from -50°C to +90°C, for example -30°C to +70°C. The device according to the invention is characterized in that the individual components of the device, for example the acoustic sensor, Protective grille, the opening for the airborne sound inlet, i.e. the sound inlet opening, the flow bypass and the sound channel, are coordinated with one another, taking airborne and/or structure-borne noise, aeroacoustics, flow and fluid dynamics, electronics and mechanics into account. The device according to the invention provides weather protection for the acoustic sensor of the device. This allows noise in road traffic to be measured under unfavorable weather conditions, such as precipitation. With the device according to the invention, noise measurements of individual road vehicles are carried out by means of the acoustic sensor. If a target volume is exceeded during such a measurement, the device controls a detection unit in order to detect the respective road vehicle, for example to photograph it, comparable to a speed measuring system. In principle, speed limits can therefore be avoided.

Road vehicles are, for example, passenger cars, commercial vehicles or tractors. Road vehicles are motor-driven, for example by means of internal combustion engines, electric motors or hybrid-electric. Depending on the speed, noise is caused by the engine, static friction between the tires and the road surface and the flow resistance of the road vehicle. For example, intentionally starting off with squealing tires constitutes noise pollution. The loudness of these noises is the amplitude, sound pressure or sound pressure level of the airborne noise emanating from these noises. For example, a threshold of 80 decibels is a target volume.

The device represents a housing for the acoustic sensor. The term acoustic sensor designates both the acoustic sensor as a component of the device and the entire device.

An acoustic sensor is a sensor that detects mechanical vibrations, for example caused by airborne sound waves, and converts them into a processable signal, for example an electrical signal such as an electrical voltage. The signal emitted by the acoustic sensor corresponds to the volume of the noise. The acoustic sensor includes an analog and/or digital signal output. The transformation takes place in two stages. In a first acoustic-mechanical In the transformation stage, the airborne sound is transformed into the movement of an object according to a specific reception principle. In the second mechanical-electrical conversion stage, the movement of the object is converted into an electrical signal according to a specific converter principle. Examples of acoustic sensors are an arrangement of a magnet and an electric coil, microphones, accelerometers, piezo sensors or strain gauges. A micro-electromechanical system, MEMS for short, comprising an arrangement of semiconductor elements that absorb vibrations, can also be used as an acoustic sensor.

The protective grille is a grille with a mechanical protective function. The protective grille is constructed in such a way that coarser foreign bodies, i.e. particles with a diameter of at least 2 mm, for example dirt particles such as mud particles, dust particles, soot particles, grains of salt, stones, insects or other particles contained in the air, do not get into the Device can penetrate.

The opening for the air inlet is positioned in the protective grille in such a way that no direct jet and/or particle stream acts on the first membrane in the axial direction of the sensor. The first membrane is thus mechanically protected by the arrangement and/or geometry of the opening. According to one aspect of the invention, the aperture or apertures are substantially 2mm wide and substantially 5mm long.

The flow bypass ensures that fluids that have entered through the air inlet, for example water, air, and small particles, such as dirt and/or dust, do not agglomerate on the acoustically permeable membrane, but rather through an opening at the outlet of the flow bypass for an air outlet again be transported out of the device. In this sense, the flow bypass is a self-cleaning flow bypass. The flow bypass is designed acoustically, flow-acoustically and flow-dynamically, so that the generation of aeroacoustic noise generated by the flow is reduced and the acting flow-dynamic forces do not negatively influence, for example damage or degrade, the subsequent components of the device.

The sound channel is used for the targeted sound guidance of the airborne sound waves to the acoustic sensor. The sound channel is acoustically specially dimensioned so that if possible no or only few and weak natural modes are formed in the usable frequency range of the acoustic sensor. This targeted dimensioning is essentially based on geometric parameters such as diameter, length, volume and shape.

The printed circuit board is also called a board or printed circuit board. The components of the printed circuit board include, for example, logic modules such as ASICS or FPGAs. For example, one component implements a high-pass filter that allows airborne sound waves with frequencies greater than 300 Hz to pass. The dynamic range of a signal is limited by means of compressor functions. The components are, for example, mounted directly on the surface of the printed circuit board, for example soldered, and are also called surface mounted devices, or SMD for short. The circuit board opening corresponds to a hole or a through hole on the circuit board for entry of the airborne sound into the acoustic sensor, which is arranged on the rear side of the circuit board in the air flow direction. The rear side of the circuit board in the air flow direction is the surface of the circuit board on which the components and the acoustic sensor are arranged.

A computing unit receives input values, calculates output values from these input values according to a specific process, and outputs the output values. For example, a computing unit is implemented by an electronic circuit unit. Logic components, ASICs, FGPAs, CPUs and GPUs are computing units. The processing unit is integrated on the printed circuit board, for example as a surface mounted device, or SMD for short.

A detection unit is, for example, an optical imaging system that generates a photo of the road vehicle. This identifies the road vehicle from which the target volume is exceeded, ie from which a noise nuisance emanates. This allows the police to stop roaring road vehicles and in the event that the target volume is exceeded penalties are imposed. This can reduce the risk of heart disease and/or diabetes for those affected who are exposed to noise pollution.

The interface is wired or wireless. In particular, the interface is designed for signal transmission using radio technology.

According to one aspect of the invention, the device is coupled to a speed enforcement system. This means that the detection unit is a camera of the speed surveillance system and the interface is an interface to the speed surveillance system. The speed enforcement system is a stationary system or a mobile system, for example mounted on a trailer.

According to a further aspect of the invention, the acoustic sensor includes a microphone. The microphone includes a microphone capsule and a transducer. The acoustic-mechanical conversion takes place in the microphone capsule. The microphone capsule includes, for example, a membrane that is excited to vibrate by airborne noise. The mechanical-electrical conversion takes place in the converter. The transducer is, for example, an electrodynamic transducer, such as in a voice coil microphone, or an electrostatic transducer, such as in a condenser microphone.

According to a further aspect of the invention, the acoustic sensor is implemented as a MEMS microphone. MEMS microphones are miniaturized microphones that are designed, for example, in SMD technology for direct use on the printed circuit board. MEMS microphones have small dimensions and are easy to process industrially, for example MEMS microphones can be assembled in a reflow soldering process. Compared to other microphones, MEMS microphones are less sensitive to high temperatures and are therefore particularly well suited for automotive applications. Alternatively, the acoustic sensor is an electret condenser microphone.

According to a further aspect of the invention, the device comprises an acoustically permeable, hydrophobic and/or lipophobic first membrane. The first membrane is downstream of the protective grille at the first end of the sound duct arranged. The flow bypass runs between the protective grid and the first membrane.

The first membrane is permeable to airborne sound waves. Due to the hydrophobic and/or lipophobic behavior, the sound channel is protected against emissions from moisture and particles, for example. According to a further aspect of the invention, the first membrane is a microporous membrane. For example, a membrane with 1.3×10 ⁹ pores/cm ² is microporous. Such a membrane is particularly waterproof and allows protection at least according to IPX4K. According to one aspect of the invention, the first membrane is designed to enable protection according to IP69K. The number 6 in IP69K means complete tightness and thus protection against the ingress of solid objects and dust. 9K designates protection against the ingress of water during high-pressure or steam jet cleaning. This is particularly advantageous for protection in automotive applications.

The degree of protection indicates the suitability of components for different environmental conditions. The protected systems are divided into corresponding types of protection, so-called International Protection, abbreviated IP codes. The ISO 20653:2013 standard Road vehicles - Degrees of protection (IP code) - Protection against foreign objects, water and contact - Electrical equipment describes the status for road vehicles. IPX6K provides protection against powerful jets of water under increased pressure, specific to road vehicles.

According to a further aspect of the invention, the shape and/or material properties of the protective grille are adapted in order to protect the first membrane, the sound channel and/or the acoustic sensor against flow-dynamic and/or static forces that arise, for example, from the relative wind or weather. The protective grille and the openings of the protective grille are designed to be rotationally symmetrical, for example. The protective grille is made of plastic, for example, and is shaped in such a way, ie has such a geometry, as to offer a degree of protection of at least IPX6K. A mechanical protective effect of the device is thus achieved and the acoustic sensor is protected against such influences.

For example, the protective screen comprises an open-cell material, for example a foam material such as an open-cell polyurethane foam material. Wind and/or water absorption can be adjusted by scalable size of pores in the material. Foam materials are characterized by a very low density and easy processing and processing. Foams are particularly easy to produce from polyurethane. Open-pored polyurethane foam is also called filter foam. Filter foam is particularly good for wind absorption. Filter foam is classified according to pore size/number of pores. The unit used is the number of pores per inch, abbreviated PPI. For example, the protective grille includes a filter foam in the range of 10 to 80 PPI.

According to a further aspect of the invention, the protective grille is an exchangeable protective grille in order to be replaced in the event of coarse soiling without having to replace the entire device.

According to a further aspect of the invention, the shape and/or material properties of the flow bypass are adapted in order to dampen the aeroacoustic noise generated by the air flow through the flow bypass and/or to protect the first membrane against flow-dynamic and/or static forces. For example, the flow bypass is shaped in such a way that there are as few edges or similar shapes in the flow bypass as possible where flow separation and/or flow turbulence can occur. Flow stalls and/or flow turbulence generate aeroacoustic noise. Flow stalls and/or flow turbulence generate aeroacoustic noise. Targeted shaping greatly reduces the susceptibility to stalls and/or flow turbulence and thus aeroacoustic noise generation as well. This is particularly advantageous in the case of relative air flows, for example during movement of the device when driving a road vehicle.

According to a further aspect of the invention, the sound channel is open at one of its two ends and at the other end with a closing element with a Reflection factor complete. Open means open to sound entry. In this sense, the sound channel, at the sound entry opening of which an acoustically permeable membrane is arranged, is open at this opening. Depending on the reflection factor, the flow resistance of the sound channel can be adjusted. The final element is the acoustic sensor, for example the microphone, or the printed circuit board.

According to a further aspect of the invention, the sound channel essentially has the shape of a truncated cone or a horn part and the first membrane is arranged at the first end of the sound channel with a larger first area and the acoustic sensor is arranged at the second end of the sound channel with a smaller second area. A horn part such as in Fig.1 the DE 38 43 033 C2 a robust system for the highly sensitive detection of airborne sound waves is disclosed. A sound channel in the form of a horn section acoustically couples the receiver particularly well to the sound field, so that as much of the external sound energy as possible arrives at the receiver. This achieves minimal acoustic damping of the flow of sound energy.

According to a further aspect of the invention, the sound channel and the flow bypass are implemented by an inflow component. The inflow component includes a bulge. The bulge includes a hollow space that runs through the axial axis and through which the sound channel is realized. The inflow component is brought together with the protective grille in such a way that the flow bypass is realized by a free space between the inflow component and the protective grille. The inflow component and its bulge are shaped in such a way that the aeroacoustic noise generated by the air flow through the flow bypass is dampened. For example, the inflow component and its bulge do not include any flow separation edges in the flow bypass.

According to a further aspect of the invention, the device comprises a housing in which the printed circuit board is arranged. The housing protects the printed circuit board and its components from mechanical and/or thermal influences. The housing includes fasteners, such as screws, around the housing and the device to be attached to an object of a traffic infrastructure, for example a traffic light mast, a crash barrier or a speed enforcement system.

According to a further aspect of the invention, the printed circuit board is arranged perpendicularly or parallel to the axial axis of the device. With the parallel arrangement of the printed circuit board, the second end of the sound channel is arranged in the radial extension of a lateral surface of the sound channel. When the printed circuit board is arranged vertically, the acoustic sensor, for example the microphone and/or the microphone capsule, is coupled to the sound channel parallel to the axial axis of the device. If the printed circuit board is arranged in parallel, the acoustic sensor is coupled to the sound channel perpendicular to the axial axis of the device, that is to say tangentially. Particularly good signals from the acoustic sensor are obtained with the parallel arrangement.

According to a further aspect of the invention, the device comprises an elastic sealing component for coupling the acoustic sensor to the sound channel and/or to the printed circuit board. The sealing component compensates for geometric tolerances when assembling the device. The elasticity ensures a defined decoupling of the acoustic sensor, including the microphone capsule, from structure-borne noise. Furthermore, the elasticity ensures an acoustically closed connection between the sound channel and the microphone capsule.

According to a further aspect of the invention, the device comprises a decoupling component for damping vibrations and/or for decoupling structure-borne noise. The decoupling component is arranged at a coupling point between the device and a component in which the device can be installed and/or by which the device can be mechanically held. The decoupling component is made of a two-component material that produces an impedance jump that has an acoustic and/or vibration-related effect. The two-component material includes a relatively soft, relatively low impedance material and a relatively hard, relatively high impedance material. The soft material is arranged in front of the hard material in the air flow direction. The impedance jump is carried out over the entire contact surface of the protective grid and the decoupling component. The decoupling component is a molded part, for example. For example, the protective grille and the decoupling component is formed from an injection molded part. According to a further aspect of the invention, the decoupling component is made from vibration-damping materials of different densities, for example from mixed-cell polyurethane foams. The decoupling component has, for example, high mechanical strength and/or good insulating properties. The device can be kept insensitive to vibrations by means of the decoupling component.

According to a further aspect of the invention, the device comprises a second membrane for venting the device. The second membrane provides static pressure balancing for the device. The proportional static pressure is compensated by the second membrane. Furthermore, the second membrane prevents the formation of condensate in the device.

According to the invention, the device can be retrofitted to objects in the traffic infrastructure as a retrofit component.

According to a further aspect of the invention, the computing unit is designed to process an artificially intelligent algorithm. The artificially intelligent algorithm is trained to classify the road vehicles depending on the signals from the acoustic sensor. The target volume depends on the road vehicle classified. The artificially intelligent algorithm is, for example, an artificial neural network trained to classify noise from road vehicles. Using the artificially intelligent algorithm, the device recognizes which type of road vehicle is causing the noise pollution. This makes it possible to distinguish, for example, noise and noise pollution from tractors or trucks, which are usually louder than cars, from noise and noise pollution from cars. The device thus recognizes which type of road vehicle F is causing the noise pollution.

The system according to the invention measures the volume of noise from a road vehicle in traffic. The system includes a device according to the invention and a detection unit operatively connected to the device. The detection unit is arranged behind the device in the direction of travel of the road vehicle. The detection unit detects the road vehicle as a function of a control signal from the device. For example, if the device measures that noises emanating from the road vehicle exceed a target volume, the detection unit, which is arranged a few meters behind the device, for example, is activated and photographs the road vehicle. The device triggers the detection unit like a light barrier of a speed enforcement system.

According to a further aspect of the invention, the detection unit comprises a camera. The road vehicle is thus photographed when a target volume is exceeded. For example, the detection unit is a speed enforcement system that includes a camera.

According to a further aspect of the invention, the system is embodied as a mobile system, for example mounted on a trailer.

• Fig. 1 eine 3D Ansicht eines Ausführungsbeispiels einer erfindungsgemäßen Vorrichtung,
• Fig. 2 eine Ausführungsbeispiel eines erfindungsgemäßen Systems umfassend die Vorrichtung aus Fig. 1,
• Fig. 3 eine isometrische Schnittansicht eines weiteren Ausführungsbeispiels einer erfindungsgemäßen Vorrichtung,
• Fig. 4 eine seitliche Schnittansicht des Ausführungsbeispiels aus Fig. 3,
• Fig. 5 eine Explosionsdarstellung des Ausführungsbeispiels aus Fig.3,
• Fig. 6 eine Schnittansicht des Ausführungsbeispiels aus Fig. 1,
• Fig. 7 eine seitliche Schnittansicht des Ausführungsbeispiels aus Fig. 1, und
• Fig. 8 eine dreidimensionale Ansicht des Ausführungsbeispiels aus Fig. 1.

The invention is explained by way of example in the following figures. Show it:

• 1 a 3D view of an embodiment of a device according to the invention,
• 2 an embodiment of a system according to the invention comprising the device 1 ,
• 3 an isometric sectional view of a further embodiment of a device according to the invention,
• 4 a side sectional view of the embodiment 3 ,
• figure 5 an exploded view of the embodiment Fig.3 ,
• 6 a sectional view of the embodiment 1 ,
• 7 a side sectional view of the embodiment 1 , and
• 8 a three-dimensional view of the embodiment 1 .

In the figures, the same reference numbers designate parts that are the same or have a similar function. For the sake of clarity, only the reference parts relevant for the respective understanding are identified in the individual figures.

1 shows a protective grid 2, a printed circuit board L, a computing unit 4 and an interface I of an exemplary embodiment of the device AKS according to the invention. Detailed views of this embodiment are in the Figures 6, 7 and 8 shown.

The arithmetic unit 4 is mounted on the printed circuit board L. The computing unit 4 processes an artificial neural network. The artificial neural network includes convolutional layers and/or fully connected layers. The artificial neural network is trained to classify noises from road vehicles F depending on the type of road vehicle F. By means of the artificial neural network, the device recognizes which type of road vehicle F is causing the noise pollution. The arithmetic unit 4 determines a control signal for a detection unit K, in order to detect the road vehicle F, as a function of signals from an acoustic sensor 1 of the AKS device when it detects that a target volume has been exceeded. The interface I provides the control signal for the detection unit K, see also 2 .

2 shows a system according to the invention. The system includes the AKS device 1 . The interface I of the AKS device is a wired interface, for example, to the detection unit K. The detection unit K is a stationary traffic speed camera for monitoring speeding. The detection unit K includes a camera CAM. The road vehicle F generates noise when driving. The respective airborne sound waves of the noises are recorded and evaluated by the AKS device. Recognizes the arithmetic unit 4 of If the device AKS exceeds the target volume, the camera CAM of the detection unit K is controlled via the interface I of the device AKS in order to detect and identify the road vehicle. The system is mounted on a trailer, for example, which can be driven to defined locations, such as locations with a high level of noise pollution. This makes the system mobile.

In the 3 , 4 and 5 in a device AKS according to the invention, a printed circuit board L is arranged perpendicularly to an axial axis A of the device AKS. In the Figures 1, 2 , 6, 7 and 8 the circuit board is arranged parallel to the axial axis A of the device AKS. When the circuit board L is arranged in parallel, a second end E2 of a sound channel 7 is arranged in a radial extension of a lateral surface of the sound channel 7 . The descriptions of the 3 , 4 and 5 apply, unless otherwise stated, to the Figures 1, 2 , 6, 7 and 8 .

The device AKS includes a component B. The component B holds the device AKS. The component B is, for example, an injection molded part or a component produced using an additive method, for example a 3D printing method.

The component B includes a circular opening. The component B is only in the 3 , 4 and 5 shown. A protective grid 2 according to the invention is inserted into this opening. The protective grid 2 is coupled to the component B by means of a decoupling component 11 according to the invention, see FIG 3 , 4 and 5 . For example, the protective grille 2 and the decoupling component 11 are made from an injection molded part. In the 3 , 4 and 5 includes the protective grille 2 four symmetrically arranged slot-shaped openings 3a, 3b, 3c and 3d. The openings 3a, 3b, 3c and 3d are entry openings for airborne sound waves into the device AKS, as are the openings 3a, 3b and 3c in Figures 1, 2 , 6, 7 and 8 . The airborne sound waves enter the AKS device in the air flow direction R. The openings 3a, 3b, 3c and 3d are arranged axially offset to an axial axis A of the device AKS. The exploded view in figure 5 shows the openings 3a, 3b, 3c and 3d, the protective grid 2 and the decoupling component 11 in a combined state.

According to the invention, an inflow component 8 is inserted into the decoupling component 11 . The inflow component 8 comprises a rotationally symmetrical bulge 9. The inflow component 8 is inserted in such a way that a free space remains between the inflow component 8, its bulge 9 and the protective grille 2. The free space forms a flow bypass 6 according to the invention. The flow bypass 6 includes air outlets 6a. The air is discharged from the AKS device through the air outlets.

The bulge 9 of the inflow component 8 comprises a hollow space H running through the axial axis A. The hollow space H has the shape of a horn part with a larger first area at a first end E1 of the hollow space H and a smaller second area at a second end E2. The first and the second surface are each base or cover surfaces of the cavity H and are symmetrical to the axial axis A. The cavity H is created, for example, by drilling a hole in the bulge.

The cavity H forms a sound channel 7. The airborne sound waves are guided through the sound channel 7 to the acoustic sensor 1. The acoustic sensor 1 is arranged on the rear side of the printed circuit board L in the direction of air flow R, that is, the surface of the printed circuit board L fitted with the electronic components. A first membrane 5 according to the invention is arranged at the first end E1 of the sound channel 7 . The acoustic sensor 1 is arranged as an extension of the second end E2 of the sound channel 7 .

The acoustic sensor 1 is an electro-acoustic sensor, for example a microphone. In the exemplary embodiments, the acoustic sensor 1 is a MEMS microphone. The acoustic sensor 1 is coupled to the sound channel 7 and to a printed circuit board 7 by means of a sealing component 10 .

The printed circuit board L is arranged in a housing G. The housing G is an electronics housing. The printed circuit board L includes components and their connections for preprocessing analog or digital signals from the acoustic sensor 1. The printed circuit board L also includes plug connections S in order to connect the printed circuit board L and thus the device AKS to an electronic control unit in terms of signals. The housing G includes a second membrane 12 designed as a venting membrane for static pressure equalization of the housing G and to prevent the formation of condensate in the housing G. The housing G also includes fastening means 13, for example screws.

Reference sign

1

acoustic sensor

2

protective grid

3a

opening

3b

opening

3c

opening

3d

opening

4

unit of account

5

first membrane

6

flow bypass

6a

air outlet

7

sound channel

8th

inflow component

9

bulge

10

sealing component

11

decoupling component

13

fasteners

E1

first end

E2

second end

AKS

contraption

A

axial axis

R

air flow direction

I

interface

K

registration unit

H

cavity

L

circuit board

S

plug connection

G

Housing

B

component

f

road vehicle

CAM

camera

Claims (9)

1. Apparatus (AKS) for measuring volumes of sounds from a road vehicle (F) in road traffic, the apparatus (AKS) comprising

   • an acoustic sensor (1),

   • a protective grille (2) for protecting the apparatus (AKS) from the ingress of coarser foreign bodies, the protective grille (2) comprising at least one opening (3a, 3b, 3c, 3d) for admitting airborne sound to the apparatus (AKS), the opening (3a, 3b, 3c, 3d) being arranged in a manner axially offset from an axial axis (A) of the apparatus (AKS),

   • a printed circuit board (L), the printed circuit board (L) comprising

   ∘ elements and the connections therebetween for preprocessing analogue or digital signals from the acoustic sensor (1), the elements being designed for analogue or digital signal processing and/or to perform filter functions, phase inversion functions, compressor functions and/or amplifier functions,

   ∘ a computing unit (4) designed to take signals from the acoustic sensor (1) as a basis for generating a control signal for a capture unit (K) when it has been identified that a setpoint volume has been exceeded, in order to capture the road vehicle (F), and

   • an interface (I) in order to provide the control signal to the capture unit (K),

   characterized in that the apparatus further comprises:

   • a flow bypass, running between the protective grille and the acoustic sensor, in order to route fluids and/or foreign bodies that have entered the apparatus (AKS) by way of airflows away from the acoustic sensor out of the apparatus (AKS), and

   • a sound channel, at whose one first end (E1) in the airflow direction (R) the protective grille is arranged and at whose second end (E2) the acoustic sensor is arranged, the diameter, length, volume, shaping and/or material properties of the sound channel being adapted to damp eigenmodes of the apparatus (AKS),

   wherein the printed circuit board (L) further comprises a printed circuit board opening, on whose rear side of the printed circuit board (L) in the airflow direction (R) the acoustic sensor is arranged.
2. Apparatus (AKS) according to Claim 1, wherein the acoustic sensor (1) comprises a microphone, the microphone comprising a microphone capsule and a transducer.
3. Apparatus (AKS) according to Claim 1 or 2, comprising an acoustically permeable, hydrophobic and/or lipophobic first diaphragm (5) that is arranged downstream of the protective grille (2) in the airflow direction (R) at the first end (E1) of the sound channel (7), wherein the flow bypass (6) runs between the protective grille (2) and the first diaphragm (5).
4. Apparatus (AKS) according to one of the preceding claims, comprising an elastic sealing member (10) for coupling the acoustic sensor (1) to the sound channel (7) and/or to the printed circuit board (L).
5. Apparatus (AKS) according to one of the preceding claims, comprising a decoupling member (11) for damping vibration and/or for decoupling structure-borne sound, wherein the decoupling member (11) is arranged at a coupling point between the apparatus (AKS) and a member (B) in which the apparatus (AKS) is installable and/or by which the apparatus (AKS) is mechanically retainable.
6. Apparatus (AKS) according to one of the preceding claims, wherein the computing unit (4) is designed to process an artificially intelligent algorithm that is trained to take the signals from the acoustic sensor (1) as a basis for classifying the road vehicles (F), the setpoint volume being dependent on the classified road vehicle (F).
7. System for measuring volumes of sounds from a road vehicle (F) in road traffic, the system comprising an apparatus (AKS) according to one of the preceding claims and a capture unit (K) that is operatively connected to the apparatus (AKS), wherein the capture unit (K) is arranged downstream of the apparatus (AKS) in the direction of travel of the road vehicle (F) and captures the road vehicle on the basis of a control signal from the apparatus (AKS).
8. System according to Claim 7,
   wherein the capture unit (K) comprises a camera (CAM).
9. System according to Claim 7 or 8,
   wherein the system is embodied as a mobile system.

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