WO2017016533A1

WO2017016533A1 - Detection device for fog detection for a motor vehicle

Info

Publication number: WO2017016533A1
Application number: PCT/DE2016/000283
Authority: WO
Inventors: Benedikt BÜTTNER; Mario Schmitt; Hans-Michael Schmitt
Original assignee: Preh Gmbh
Priority date: 2015-07-24
Filing date: 2016-07-22
Publication date: 2017-02-02
Also published as: CN209248021U; DE102015112103A1

Abstract

The invention relates to a detection device for fog detection (1) for a motor vehicle (5), comprising: an optoelectronic fog sensor device arranged in the front region of the motor vehicle (5), which is designed to impinge a spatial region (4) with at least one first optical transmission signal and to detect a reflected receiving signal from said spatial region (4), and to produce an electrical signal as a function of the strength of the receiving signal, wherein the detected receiving signals correlate with light intensities; at least one further sensor (2) which is provided for detecting data about the operating state of the vehicle and/or detecting vehicle environment data of the immediate vehicle environment. The invention is characterised in that an evaluation unit determines whether the receiving signal is an interference signal or a useful signal by considering the determined data concerning the operating state of the vehicle and/or the vehicle environment data of the immediate vehicle environment.

Description

Detection device for detecting fog for a motor vehicle

The invention relates to a detection device for detecting fog according to the

Preamble of claim 1.

Optoelectronic sensor devices (Lidar, "Light Detecting and Ranging"), in particular laser-based systems, enable the detection of objects at a distance of more than 100 m from the motor vehicle with a relatively high measuring accuracy and are already state of the art Driving comfort and to increase safety, such as a lane change assistant, a traffic jam assistant, monitoring the dead angle, a crossing assistant and a precrash sensor Depending on the particular application, the sensor device is installed in the motor vehicle.

From US 5 118 180 A is a method and a device for the determination of

Visibility of a driver in fog or other disturbances known. In this case, a transceiver device is arranged in the front region of a vehicle, which as

Rangefinder acts. A series of measuring beams is directed by the rangefinder to different measuring areas of the road surface. The of the

Road surface backscattered radiation is detected by metrology. If the weather conditions change, for example due to fog or other disturbing influences, the characteristic of the backscattered signal will change or no stray signal will be received. The driver is alerted to a dangerous situation by an acoustic or visual warning signal.

From US 5,206,698 A is a sensor device for the detection of atmospheric

Disturbances known. The sensor devices has a transmitter for linear polarized

Radiation, a receiver having a first receiving device, which measures the intensity of the backscattered radiation from the transmission beam cone in the plane of polarization and perpendicular thereto, and with a second receiving device which measures the intensity of the backscattered radiation from an annular space outside the transmission cone and an evaluation device for Evaluation of the measured signals in order to determine whether a fog, snow or rain wall or a fixed visual obstacle is present at a distance to be determined. The type of visual obstruction, as well as its

CONFIRMATION COPY Distance from the lidar device will be shown on a display. The lidar device can be used as a distance warning device in a motor vehicle, and, in connection with a data processing device and a speedometer, which the

Measures the speed of the motor vehicle, using that, depending on the environmental conditions determined from the measured data optimum speed of the motor vehicle is achieved by an action on the drive and / or braking system.

US Pat. No. 5,987,152 A discloses a method for determining the range of vision, in particular for the movement of a motor vehicle. In the method, the original images taken by an optoelectronic recording device are transformed into image features that identify locations of defined brightness changes in the original images. About a distance determination of the image features relative to the optoelectronic recording device and a subsequent filtering of

Distance values will be the current visibility of a vehicle driver or one

Image processing based sensor system determined. The advantage over

Conventional active method is that without active transmitter in addition to transmissions in the atmosphere of the real Sehobjektkontrast flows into the determination of the visibility.

However, the systems described above are susceptible to detection of

Interference signals, which are mistakenly detected as fog, so that it can lead to an unfounded warning message. This problem occurs in particular if the space area to be monitored by the detection device and thus acted upon is comparatively large or incomplete. For example, reception signals can be triggered by the reflection on vehicles in front, on bridges, in tunnels, on signs located above the roadway, or by branches located above the roadway and can not reliably be distinguished from a signal triggered by fog. Also in the systems described above is not reliable between a visibility restriction by rain and a

Visibility limitation distinguished by fog. However, this reliable distinction is necessary, for example, for an automatic regulation of the rear fog lamp, since a mistakenly switched on rear fog lamp the subsequent

Motor vehicle can dazzle and thus possibly increases the risk of accidents. Discovering these disadvantages, it is the object of the present invention to provide a fog detection detection device which can distinguish a fog condition more reliably from a non-fog condition.

This object is achieved by a detection device for detecting fog with the

Characteristics of claim 1, and solved by a method according to the independent method. Advantageous embodiments of the detection device for

Fog detection are each the subject of the dependent claims. It should be noted that the features listed individually in the claims can be combined with each other in any technologically meaningful way and more

Embodiments of the invention show. The description, especially in the

In connection with the figures, the invention additionally characterizes and specifies.

The invention relates to a detection device for detecting fog, wherein the

Detection device according to the invention comprises an opto-electronic fog sensor device, which is designed to act on a spatial area with at least a first optical transmission signal and from this space area a reflected

Receive signal to detect. Thus, the fog sensor device is as

Reflection light barrier, also called open light barrier, formed. The

Detection device for detecting fog is preferably arranged in the front region of the motor vehicle, and even more preferably the detection device for detecting fog is arranged behind the windshield in the vehicle interior.

An optical transmission signal in the sense of the invention is for example a pulsed or a continuous laser beam, preferably the optical transmission signal is also a pulsed or a continuous light generated by a light-emitting diode (LED). The optical transmission signal is preferably in the infrared spectral range, more preferably in the near-infrared spectral range.

The applied space is determined by the arrangement of the transmitter and the

Receiver or the arrangement of the emission or reception characteristic specified. The transmitter and the receiver are arranged so that at least a partial overlap is present. Preferably, the transmission and reception characteristics are aligned so that the area of space impinges with increasing distance to infinity, for example, because the main emission of the transmitter and the main receiving direction of the transmitter, also referred to as their optical axes, parallel to each other or at an acute angle cut less than 10 °. The applied spatial area is therefore the result of the conjunction of the optical reception profile of the receiver and the optical beam profile of the transmitter. The

Connecting line between the geometric center of the acted upon

Spatial region and the geometric center between the transmitter and receiver, the resulting detection direction.

It is preferably provided that the transmitter and the receiver are aligned so that their optical axes are parallel or intersect at an acute angle with an angle of less than 10 °, preferably less than 5 °, more preferably less than 3 °.

According to a preferred embodiment, the transmitter and the receiver are so

aligned so that their optical axes in the area directly on the transmitter and receiver have a distance of less than 20cm, preferably less than 15cm, more preferably less than 10cm. For example, transmitter and receiver are arranged on a common circuit board. For example, emitter and receiver are spaced apart, with an air vent or rear mirror base in between.

The detection device for detecting fog is preferably arranged so that its detection direction is perpendicular to a tangential plane of the windscreen to unwanted reflections of the optical transmission signal when passing through the

Windscreen to reduce, otherwise to an additional reduction of the

Receive signal lead.

If matter such as, for example, fog or very small drops of water, particles, signs, tunnel walls, branches or similar objects is present in the area acted upon, the transmitted signal emitted by the transmitter is reflected. Depending on the

Reflective properties of the matter in the area acted upon the optical transmission signal is reflected. In the detection of fog according to the present invention, the more the fog is transmitted, the more dense the transmission signal radiated by the optical transmitter. detected by the receiver as a received signal

Light intensities consequently increase as the density of the fog increases. According to the invention, an electrical signal is output to the evaluation unit for further analysis, depending on the strength of the received signal. The space area acted upon according to the invention is preferably located in front of

Motor vehicle. Signs, tunnels, bridges or branches located above the roadway, for example, can trigger an interference signal in the area of the space acted upon. An interference signal in the sense of the invention is consequently a reception signal lying above the background noise (baseline), which is not based on a fog condition. A useful signal in the sense of the invention, however, is a received signal, which is based on a fog state. To determine whether the received signal is a useful signal or an interference signal, the detected received signals, taking into account the data on the

Vehicle operating state and / or taking into account the vehicle environment data of the immediate automotive environment as soon as possible in real time, for example, analyzed and evaluated in less than a few decades milliseconds in an evaluation.

In one embodiment, the reception signal is set to a useful signal based on a threshold value: If the received signal is above a predetermined threshold for fog detection, a fog condition is detected and, for example, a warning signal issued to the motor vehicle driver and / or the vehicle electronics uses the detection result based on the vehicle exterior lighting to control.

According to the invention, the threshold for fog detection is adapted according to the respective data about the vehicle operating state and / or the respective vehicle environment data of the immediate motor vehicle environment. Defining the threshold for

Nebeldetektion takes place preferably dynamically, i. For example, the threshold for fog detection is constantly updated and adjusted in accordance with the data that is constantly being acquired.

Preferably, the data about the vehicle operating state, for example, the

Speed, the wiping speed of the windscreen wiper, the time, the

Season, the use of the headlamps, the use of the rear fog lamp, geographical coordinates transmitted using GPS with those in the maps of the

Navigation information is correlated via, for example, waters or tunnels.

Preferably, the vehicle environment data of the immediate automotive environment may include, for example, climate data such as temperature, humidity, air pressure, rainfall, or brightness in the vehicle environment. Preference is given to Vehicle environment data of the immediate vicinity of the motor vehicle in relation to the time, the season and set to the geographical coordinates.

For example, in heavy rain, the water on the road is whirled up as spray by leading vehicles. This spray consists of very small drops of water and gives a received signal which the received signal of a

Mist condition could correspond. Preferably, using a further sensor, for example a rain sensor, the amount of rain is determined permanently and adjusted according to the amount of rain, the threshold for fog detection. That if the amount of rain is very large, the threshold is set high, and if the amount of rain is small, the threshold is lowered. Through this adaptation of the

Threshold is adjusted to the sensitivity of the optoelectronic fog sensor device according to the detected rainfall and thus a false

Noise detection of spray avoided.

The impacted area of space is preferably above the specified clearance for the road, so that possibly leading vehicles are below the applied space. In addition, the resulting cuts

Detection direction of the road surface, preferably in an angular range of preferably 30 ° -90 °, more preferably in an angular range of 30 ° -80 ° and most preferably in an angular range of 30 ° -60 °. Whereby the angle range is preferably to be selected such that the applied space area lies as far as possible in front of the motor vehicle, wherein the

However, the resulting detection direction as possible no intersection with a

Having driving vehicle. A fog detection in such a predetermined space area allows the fog to be detected in front of the vehicle without receiving an interference signal from preceding vehicles. The motor vehicle driver can therefore be warned early and adjust the driving behavior accordingly, for example, the speed can be reduced.

In a further refinement, the data about the vehicle operating state are preferably obtained via the data bus, which is already available in the motor vehicle, and forwarded to the evaluation unit, i. it is also possible to integrate sensors independent of the detection device for detecting fog into the evaluation unit.

The evaluation unit is preferably integrated in the optoelectronic fog sensor device. The detection device according to the invention for detecting fog further comprises a possibility for storing the detected received signals and also the measured data on the vehicle operating state and / or the vehicle environment data of the immediate automotive environment. The data are stored, for example, in each case with the corresponding geographical coordinates and the time, so that both the time course and the course of the data along the route can be called up. The stored data can for example be deposited so that the data is available again when the same route is traveled again.

Preferably, the temporal and / or spatial course of the received signal is used for an additional distinction between a fog state and a non-fog state. For this purpose, the temporal and / or spatial course in the evaluation unit is characterized. For example, a slowly increasing temporal and / or spatial course of the received signal is characteristic of a fog state and a step-like rise characteristic of a tunnel. A stepwise temporal and / or spatial course is a course in which the detected signal jumps from a lower level to a higher level or from a higher level to a lower level within a predetermined distance or time span. The signal is there

exemplary for the received signal or for corresponding data on the

Vehicle operating state or for corresponding vehicle environment data of

immediate motor vehicle environment. Preferably, the predetermined distance is less than 10m, more preferably less than 8m, and the preferred time is the time in which the preferred distance is traveled at the current speed. For example, at a speed of 72 km / h, the predetermined time would be 500 ms and more preferably 400 ms.

For example, the temporal and / or spatial course of the received signal reflected by a tunnel is step-shaped. The detected received signal is in the case of a tunnel detection but with high probability above the threshold to

Fog detection. If only the strength of the received signal is taken into account, a mist condition would thus be erroneously detected. However, a step-shaped course of the received signal is not characteristic of a fog state, thus a fog state is excluded in the case of a step-like rise of the received signal by the evaluation unit. Preferably, a tunnel is detected via the change of the brightness value and thus a false detection of a fog state is avoided. If the brightness value falls below a threshold of preferably 20%, more preferably 15% and most preferably 10% of the previously measured brightness value over a predetermined period of time or over a predetermined distance, a tunnel is detected. The evaluation unit then switches to a tunnel mode "Car is driving through a tunnel" and the fog measurement is paused. The tunnel detection by means of a brightness sensor is used in particular on the day.

The tunnel mode is exited when it suddenly, i. gradually becomes bright again, i. the brightness value exceeds a predetermined time span or over a predetermined distance a predetermined threshold value. Preferably, the threshold is between 40% and 60%, more preferably between 45% and 55%, and most preferably 50% of the brightness value detected prior to tunnel detection.

Preferably, the distance covered in the tunnel mode is determined, for example, by a counter, preferably via the data bus available in the motor vehicle anyway. If a predetermined distance is exceeded, the tunnel mode is switched off again, thus avoiding that the fog sensor device falsely pauses.

Preferably, a recognized tunnel is deposited, for example, with the geographical coordinates and the distance in a database in the motor vehicle and / or online. These data can be used when the route is repeatedly traveled, i. the current data is compared with the already stored data and so is the

Likelihood of erroneous tunnel detection by repeatedly traversing the route additionally reduced.

In addition, further data can be used for the plausibility analysis,

For example, data available online about the region, such as the time history of the temperature of the last few days can be compared with the current and / or the predicted temperature. For example, in the case of strong temperature fluctuations, a fog probability can be predicted even before the detection of fog.

For example, the temporal temperature profile for the places to be passed

be downloaded at the beginning of the journey as entered in the navigation system. This can be done for example by a with the evaluation automatically connected additional device such as a smartphone or a

Smartwatch done or by an intended in the car Internet connection. In addition, particularly vulnerable routes can be deposited in the evaluation unit which is compared with the proposed by the navigation system route, or with the current geographical coordinates. Will for the of the

Navigation system predetermined route detected an increased fog probability, takes place already before the Nebeldetektion a warning message. The warning message can be visual and / or audible and / or haptic. In addition, data available on-line during the journey can be downloaded and / or data from mist-warning systems set up on the route can be used. The vehicle environment data recorded by the motor vehicle while driving can be collected, for example, together with the geographical coordinates in a database stored in the motor vehicle and thus lead to an improved prognosis for the probability of mist formation along the route. In addition, for example, the coordinates at which fog has actually been detected and the associated data, such as the temperature profile, the humidity, the brightness, etc. are stored and stored in a database in the vehicle. This database can also be put online with the approval of the motor vehicle driver and possibly also be used by other road users. The data stored in the motor vehicle and / or the online data are compared with the coordinates of the vehicle and can be used in the fog detection or warning at an increased fog probability.

Preferably, the temporal and / or spatial course of the received signal is analyzed and it is based on the data on the vehicle operating condition and / or the

Vehicle environment data of the immediate automotive environment, the threshold is adapted to Nebeldetektion. In addition, during the analysis, an in

Motor vehicle deposited database and / or an online provided

Database for predicting a fog probability or for comparison with the current measurement data can be used.

According to the invention, the method for detecting fog for a motor vehicle comprises applying a spatial region having at least one first optical transmission signal and detecting a reflected reception signal from the applied one

Room area, by an arranged in the front region of the motor vehicle opto-electronic fog sensor device. In a temporally parallel process step, over detects at least one further sensor, data about the vehicle operating state and / or vehicle environment data of the immediate automotive environment. Based on the strength of the received signal, an electrical signal is generated and sent to the

Evaluation unit forwarded.

The received signal and / or the data about the vehicle operating state and / or the vehicle environment data of the immediate motor vehicle environment are preferably evaluated in the evaluation unit.

Based on the evaluation takes place taking into account the determined data on the vehicle operating condition and / or the vehicle environment data of the immediate automotive environment, a determination whether the received signal is an interference signal or a useful signal.

Preferably, the determination is made whether the received signal is an interference signal or a useful signal, based on a threshold for fog detection, the threshold for fog detection on the basis of the determined data on the vehicle operating condition and / or the

Vehicle environment data of the immediate automotive environment, preferably continuously, is adjusted.

In the provided evaluation unit, the detected received signals and / or the determined data on the vehicle operating state and / or the

Vehicle environment data of the immediate automotive environment stored. In the evaluation unit is then preferably the temporal and / or spatial course of the

Receiving signal and / or the temporal and / or spatial course of the determined data on the vehicle operating condition and / or the vehicle environment data of

evaluated immediate motor vehicle environment. The temporal and / or spatial course of the received signal and / or the spatial course of the determined data over the

Vehicle operating condition and / or the vehicle environment data of the immediate automotive environment is then used in the further process for determining whether the received signal is a useful signal or a noise signal.

In the method for detecting fog, it is preferred to obtain a sighting range from a useful signal.

Further features and advantages of the invention will become apparent from the following description of a non-limiting embodiment of the invention, which in the The following will be explained in more detail with reference to the figures. These drawings show schematically:

1 shows a detection device for detecting fog located in the front region of a motor vehicle;

2: in each case a 2D representation of the optical beam profile of an optoelectronic

Fog sensor device;

3 shows a characteristic time profile of a received signal and a

Brightness signal in case of tunnel detection in a non-fog state;

4 shows a characteristic time profile of a received signal and a

Brightness signal in case of fog.

In the different figures, equivalent parts are always provided with the same reference numerals in terms of their function, so that these usually only once

to be discribed.

1 schematically shows an inventive arrangement of a detection device for detecting fog 1 in the front region of a motor vehicle 5, wherein the opto-electronic fog sensor device 3 is arranged behind the windshield in the vehicle interior. The optical axis 8 of the optoelectronic fog sensor device 3 intersects the roadway 9 at an angle 10 of approximately 45 °. Due to this angular adjustment, the optical axis 8 is located at a height of 1 m attached optoelectronic

Mist sensor device 3, with a hood length of 1, 5m already on the front bumper at a height of about 2.5m. This ensures that the optical axis 8 of the optoelectronic fog sensor device 3 has no point of intersection with a motor vehicle 14 traveling in front. At the same time is the acted upon

Space region 4 of the optoelectronic fog sensor device 3 still relatively far ahead of the motor vehicle 5 at a relatively low height with respect to the roadway 9. Schematically, another sensor 2 is arranged on the roof of the motor vehicle 5, wherein the further sensor 2 at each for the detection of respective data meaningful place on the

Motor vehicle 5 may be attached. By the data of the other sensor 2 is the Threshold for fog detection adjusted accordingly. If a fog condition is detected, depending on the visibility both a warning message to the

Automobile driver as well as an automatic control of the fog lamp 15 done.

2a and 2b show a plan view of the optical beam profile 6, 7 of the transmitter 11 and the receiver 12. The transmitter 11 and the receiver 12 are each arranged so that their optical axes intersect. The angle of intersection of the two optical axes gives, with the same optical beam profile, the size of the optoelectronic

Nebul sensor device 3 acted upon space area 4 before. The acted on

Spatial region 4 results from the conjunction of the optical beam profile of the transmitter 6 with the optical beam profile of the receiver 7. The connecting line between the

Geometric center of the applied space region 4 and the geometric center between transmitter 11 and receiver 12, the resulting detection direction 8 of the optoelectronic fog sensor device 3 before.

The method according to the invention and the device according to the invention are in principle suitable both for the alignment of the optical axes shown in FIG. 2a and for the orientation shown in FIG. 2b, since in both cases a plausibility check of the fog detection takes place despite the extended applied space. But with increasing space but the risk of misdetection increases, arise

Advantages of the invention in particular in such alignments of the optical axes, in which the applied space area is large, for example, ends at a distance from the fog sensor device, which is more than 2.5 m, preferably more than 3m, more preferably more than 5m. In particular, the advantage according to the invention is achieved when the optical axes are at infinity or approximately at

Intersect infinite, as illustrated in Figure 2b. Such

Mist sensor device according to the design shown in Figure 2b can be realized comparatively inexpensive.

In Figure 3, a motor vehicle 5 can be seen, which with a inventive

Detection device for fog detection 1 in the front region of the motor vehicle 5 is equipped. A preceding motor vehicle 14 is located below the applied space region 4 and is therefore not detected as an interference signal. The acted on

However, space region 4 is above the specified for roads clearance gauge, thus the tunnel located in front of the motor vehicle 5 13 is detected as an interference signal. 3a shows a characteristic step-shaped time profile of a received signal 7, which with an optoelectronic fog sensor device 3 of a, with a constant

Speed on a tunnel 13 approaching motor vehicle 5 has been detected. This characteristic step-shaped signal already allows a fog state

exclude. On the basis of the brightness values of the immediate vehicle environment independently obtained by the optoelectronic fog sensor device, detected by a brightness sensor, the result of the analysis of the time course of a vehicle can be obtained

Receiving signal 7 are checked. The time profile of the brightness value shows a temporally offset inverse curve of the time profile of the received signal 7. Thus, the result based on the detected received signal can be confirmed by an independent measuring method. In particular, on the day of the analysis of the brightness values tunnel 13 are detected and the motor vehicle 5 is switched to a tunnel mode. In tunnel mode, the measurement pauses for fog detection.

In Figure 4, a motor vehicle 5 can be seen, which with an inventive

Detection device for fog detection 1 in the front region of the motor vehicle 5 is equipped. A preceding motor vehicle 4 lies below the applied space region 4 and is therefore not detected as an interference signal. The mist 16 is shown here via three upward arrows, the arrow being the density of the mist 16. 4 a shows a characteristic monotonously increasing time profile of a received signal 7 detected by an optoelectronic fog sensor device 3, a motor vehicle 5 approaching the mist 16 at a constant speed. If the received signal 7 lies above the threshold adapted in accordance with the data of the further sensor 2 a fog condition is detected. In addition, the characteristic time characteristic of the brightness values shown in FIG. 4 b can also be used to distinguish between a fog state and a non-fog state.

Claims

claims

1. Detektionsvornchtung for fog detection (1) for a motor vehicle (5) comprising: an in the front region of the motor vehicle (5) arranged optoelectronic

A fog sensor device (3), which is designed to apply a spatial region (4) to at least one first optical transmission signal (6) and to detect a reflected received signal (7) from this spatial region (4), and in dependence on the strength of the received signal (7 ) to an electrical signal

Generating, wherein the detected received signals correlate with light intensities; at least one further sensor (2), which is provided for the detection of data about the vehicle operating state and / or for the detection of vehicle environment data of the immediate automotive environment, such as climate data; characterized in that an evaluation unit taking into account the determined data on the

Vehicle operating condition and / or the vehicle environment data of the immediate automotive environment determines whether the received signal (7) is an interference signal or a useful signal.

2. Detektionsvornchtung for mist detection (1) according to claim 1, in which a

Receiving signal (7) is set as a useful signal when the received signal (7) exceeds a threshold for fog detection, wherein the threshold for fog detection is adjusted according to the determined data on the vehicle operating condition and / or the vehicle environment data of the immediate automotive environment.

3. Detektionsvornchtung for fog detection (1) according to one of the preceding claims wherein the temporal and / or spatial course of the received signal (7) for

Determining whether the received signal is a useful signal or an interference signal is used.

4. Detektionsvornung for mist detection (1) according to one of the preceding claims, in which the applied space area (4) above the road

predetermined airspace profile and the resulting detection direction (8) of the optoelectronic fog sensor device (3) the Fahrbahnebene (9) in an angular range (10) of preferably 30 ° -90 °, more preferably in an angular range of 30 ° -80 ° and most preferably in an angular range of 30 ° -60 °.

5. Detektionsvornchtung for mist detection (1) according to one of the preceding

Claims in which the data on the vehicle operating condition and / or the vehicle environment data of the immediate automotive environment are determined by a data bus.

6. Detektionsvornchtung for mist detection (1) according to one of the preceding

Claims, in which the evaluation unit in the optoelectronic

Fog sensor device (3) is integrated.

A fog detection detection apparatus (1) according to any one of the preceding claims, wherein the transmitter (11) and the receiver (12) are aligned so that their optical axes are parallel or at an acute angle with an angle of less than 10 ° , preferably less than 5 °, more preferably less than 3 °.

8. Detection device for detecting fog (1) according to one of the preceding claims, wherein the transmitter (11) and the receiver (12) are aligned so that their optical axes in the area directly on the transmitter and receiver a distance of less than 10cm, preferably less than 5cm, more preferably less than 3cm.

9. Nebelungserkennung Detektionsvornchtung (1) according to any one of the preceding claims, in which the transmitter (11) within the integration time of the receiver (12) outputs a transmission signal and the integration time of the receiver is dependent on the speed.

10. A method for detecting fog for a motor vehicle (5), comprising the following method steps:

- applying a space region (4) with at least one first optical transmission signal (6), by an arranged in the front region of the motor vehicle opto-electronic fog sensor device (3), comprising a transmitter (11) and a receiver (12);

- Detection of a reflected received signal (7) from the acted upon

Room area (4) through the arranged in the front region of the motor vehicle opto-electronic fog sensor device (3);

Generating an electrical signal based on the strength of the

Receive signal (7);

- Measurement of data about the Fahrzeugbetnebszustand and / or measurement of vehicle environment data of the immediate automotive environment with at least one further sensor (2);

a subsequent evaluation of the received signals taking into account the data about the vehicle operating state and / or the

Vehicle environment data of the immediate automotive environment in an evaluation unit;

- subsequent determination by the evaluation unit, whether the received signal (7) is either an interference signal or a useful signal;

- Optionally, in the case of a useful signal, a warning signal is output.

11. A method for detecting fog for a motor vehicle (5) according to claim 10 in

which the determination of whether the received signal (7) either an interference signal or a useful signal is based on a threshold for Nebeldetektion, wherein the threshold for Nebeldetektion based on the determined data about the Fahrzeugbetnebszustand and / or the vehicle environment data of the immediate automotive environment is adjusted.

12. A method for detecting fog for a motor vehicle (5) according to one of the preceding method claims 10 or 11, wherein the received signals are stored and the temporal and / or spatial course of the received signal (7) is evaluated and the temporal and / or spatial course of the received signal (7) is used for the determination between a useful signal and a noise signal.

13. A method for detecting fog for a motor vehicle (5) according to one of the preceding method claims 10 to 12, wherein the transmitter (11) and the receiver (12) of the fog sensor device (3) are aligned so that their optical axes are parallel or under an acute angle with an angle of less than 10 °, preferably less than 5 °, more preferably less than 3 °.