Sensor arrangement for a motor vehicle and motor vehicle

Abstract

A sensor arrangement (4) for a motor vehicle (1), comprising a sensor (5) with a cover (7) through which the sensor (5) detects information from its detection area, and a cleaning device (8) for cleaning the cover (7) with cleaning fluid (11) from a cleaning fluid reservoir (12), wherein the cleaning device (8), which is also designed as a cooling device, has a cooling circuit utilizing the cleaning fluid (11) with a first line section from the cleaning fluid reservoir (12) to a cooling area (17) of the sensor (5) to be cooled, which is at least partially different from the cover (7), and a second line section (18) for returning the cleaning fluid (11) to the cleaning fluid reservoir (12), characterized in that a cooling section (20) of the cooling circuit through which the cleaning fluid (11) flows to cool the cooling area (17) is not sealed,wherein the cleaning device (8) has a funnel-like collecting means (21) of the second line section (18) for the cleaning liquid (11) flowing through the cooling area (17), wherein the funnel-like collecting means (21) is arranged higher than the cleaning liquid reservoir (12) for transporting the cleaning liquid (11) by gravity.

Description

[0001] The invention relates to a sensor arrangement for a motor vehicle, comprising a sensor, in particular an optical sensor, with a cover through which the sensor detects information from its detection area, and a cleaning device for cleaning the cover with cleaning fluid from a cleaning fluid reservoir. The cleaning device, which is also designed as a cooling device, has a cooling circuit that uses the cleaning fluid, comprising a first line section from the cleaning fluid reservoir to a cooling area of ​​the sensor to be cooled, which is at least partially different from the cover, and a second line section for returning the cleaning fluid to the cleaning fluid reservoir. The invention also relates to a motor vehicle.

[0002] Modern motor vehicles often have a large number of sensors, in particular sensors directed at the surroundings of the motor vehicle. In addition to the use of radar sensors and / or ultrasonic sensors, optical sensors such as cameras or lidar sensors are often used. The sensors collect information, specifically sensor data, from their detection area, which is directed at the surroundings, usually through a cover, which can include or be a protective cap, a radome, an optical arrangement, a window of the motor vehicle, and the like. In the case of cameras, the cover can also include a lens, for example. In the case of sensors arranged behind a windshield or another window of the motor vehicle, this window can also be understood as the cover if the sensor scans the detection area through it.Particularly in the case of sensors directed towards the surroundings of the motor vehicle, the cover can form part of an outer surface of the motor vehicle. In such cases, but also in other cases, the cover can become soiled, which can impair the function of the sensor. Therefore, it has already been proposed in the prior art to associate a cleaning device with the sensor, which has a cleaning fluid reservoir from which the cleaning fluid can be supplied to the sensor cover for cleaning purposes, for example by means of an application arrangement. In particular, the cleaning fluid can be water with a cleaning agent additive and / or an antifreeze additive, as is often referred to as "windshield washer fluid". The cleaning fluid can, for example, be applied to the cover via at least one nozzle, optionally under pressure, in order to remove soiling.The application arrangement can, in particular, comprise a pump. The cleaning fluid reservoir, for example a washer fluid reservoir, can also be associated with cleaning devices for other surfaces or areas of the motor vehicle, for example, for windshield cleaning.

[0003] Sensors, especially optical sensors, have an operating temperature range within which their functionality can be guaranteed. If the maximum operating temperature within this operating temperature range is exceeded, malfunctions or even damage may occur. Especially if the sensors are installed in locations particularly exposed to sunlight, for example, on or near the roof of the vehicle, there is a risk that this maximum operating temperature will be exceeded. Cooling of the sensor may then be necessary.In particular, in the case of sensors arranged in the roof area of ​​a motor vehicle, it is not conceivable, or only with great effort, to couple the sensor to a conventional cooling circuit of the motor vehicle, for example to a cooling system for the drive and / or battery, since such cooling systems are usually kept away from the interior since the cooling media used can pose a danger to occupants.

[0004] In the prior art, active ventilation was proposed for such sensors, particularly those installed in the roof area of ​​motor vehicles. Fans are used to direct an airflow onto the sensor. However, such a solution proves to be technically complex and costly. Channels must be created for the supply and exhaust air paths, and a fan is required. If the sensors are positioned near the passenger compartment, acoustic decoupling from active fans is also difficult. The supply air must already be cooled, and such cooled supply air is insufficient after a long period of standing in the sun.

[0005] It has also been suggested that ambient air should flow passively around the sensor. However, this is only feasible at higher driving speeds. When the vehicle is stationary or traveling at walking pace, sufficient airflow cannot be ensured. Providing additional water cooling is also technically and cost-intensive, as it also requires additional weight and additional installation space for the cooling circuit and the cooling medium.

[0006] DE 10 2021 001 922 A1 discloses a sensor device for a motor vehicle, wherein a channel of the sensor device is open with a channel outlet toward a measuring surface of the sensor, so that fluid flowing from the channel outlet flows along the measuring surface and cleans the measuring surface. Increased efficiency and reduced noise generation are now to be achieved by routing the channel along a cooling surface that is different from the measuring surface, so that the fluid flowing through the channel flows along the cooling surface to cool the cooling surface.

[0007] DE 10 2018 106 083 A1 relates to a heat sink with at least one fluid conducting element, wherein the heat sink has a heat collection surface, a heat transfer surface with at least one heat dissipation surface, and at least one fluid conducting element. The arrangement of the heat collection surface in operative connection with the heat source causes heat to be dissipated from the heat source through the at least one heat dissipation surface. The fluid conducting element directs a fluid toward the at least one lens of the heat source, such that the fluid flows past an outer surface of the at least one lens to clean the surface of the at least one lens. The warm air rejected by the sensor unit dries the lens and provides an anti-fogging effect.

[0008] DE 10 2019 007 248 A1 relates to a sensor device for a motor vehicle, which has at least one sensor covered by a sensor cover. The sensor device can be cooled by a heat sink and has a cleaning device comprising an air duct for directing an air flow onto the sensor cover and a flow device for generating the air flow. An air flow heated by the heat sink can be directed by means of the flow device to heat the air flow in the air duct. The sensor cover can be heated by means of the thus heated air, which can, for example, melt ice.

[0009] DE 10 2018 221 886 A1 discloses a device for cooling a surface and / or a volume of a vehicle sensor. The sensor has a functional surface for recording measured values, which can be cleaned by a cleaning system with a nozzle and a cleaning agent. The cleaning agent is used to cool the sensor. It is applied to a surface of the sensor from the outside using an additional nozzle, with cooling occurring through evaporation of the cleaning agent on the surface, known as evaporative cooling. In addition, cleaning agent is passed through a closed line inside the sensor to cool the sensor.

[0010] Devices for cooling and cleaning a sensor of a motor vehicle are also known from DE 10 2019 004 136 A1, US 2020 / 0 001 331 A1, JP 2020 - 93 612 A and JP 2018 - 72 520 A. Here, too, cooling and cleaning are carried out using the same fluid. A closed cooling circuit is taught, which is extended by an outlet with a washer nozzle through which the sensor or a sensor cover can be wetted from the outside. The cooling circuit comprises a multi-way valve or several individual valves, which are configured to direct the fluid through a heat sink of the sensor in a first switching position and to direct it out of the cooling circuit to the washer nozzle in a second switching position.

[0011] DE 10 2020 107 759 A1 discloses a vehicle roof with at least one sensor module with at least one environmental sensor. For cleaning the at least one sensor module, the vehicle roof comprises at least one cleaning device. This, in turn, comprises at least one fluid nozzle, by means of which a cleaning fluid can be applied to a sensor-transparent area and which is connected to a line arrangement for the fluid supply, as well as a temperature control device for temperature control of the sensor module(s), which is connected to the line arrangement for the fluid supply via a thermal fluid line.

[0012] US 2022 / 0 185 241 A1 discloses a cooling circuit with a multi-way valve and an outlet to which a cleaning nozzle for cleaning a sensor is connected. The multi-way valve directs the fluid either back to the tank, creating a closed circuit, or to the outlet to the cleaning nozzle. Both the cooling circuit itself and the outlet to the cleaning nozzle run through a sensor, which is thus constantly cooled by the fluid.

[0013] In addition, DE 10 2019 004 137 A1 relates to a multi-way valve which can be connected to a pump on the inlet side and to a heat sink and a washing nozzle on the outlet side, wherein the multi-way valve is designed to fluidically connect the pump to the heat sink in a first switching position and to fluidically connect the pump to the washing nozzle in a second switching position.

[0014] Furthermore, DE 10 2019 100 127 A1 relates to a system including a computer including a processor and a memory, wherein the memory stores instructions executable by the processor to determine an amount of obscuring material on a vehicle sensor, to determine a temperature of the vehicle sensor, and to actuate a liquid pump arranged to pump liquid to the vehicle sensor and an air pump arranged to pump air to the vehicle sensor based on the amount of obscuring material and the temperature.

[0015] The invention is based on the object of providing a cooling option for a sensor in a motor vehicle that is technically simple and cost-effective to implement and can be used continuously over a longer period of time.

[0016] This problem is solved by the features of main claim 1 and subsidiary claim 9. Advantageous further developments are the subject of the subclaims.

[0017] It is therefore proposed that the cleaning fluid required for cleaning be used to cool the sensor via a cooling circuit. Using the existing cleaning fluid volume to cool the sensor enables efficient cooling with minimal additional effort. Separate cooling circuits, lines, and media containers for additional cooling, such as water cooling, are not required.

[0018] The cooling system proposed according to the invention can also be operated over a longer period of time independently of a cleaning process, since the cleaning fluid is returned to the cleaning fluid reservoir due to the use of a complete cooling circuit and can thus be used again and again. Furthermore, the cooling process is not coupled to the cleaning process. In this case, such cleaning fluid reservoirs in motor vehicles are usually larger, for example in order to be able to clean other places, such as windows, so that a fairly large "cold reservoir" already exists. This is at least substantially not reduced within the scope of the present invention, since the cooling circuit ensures that cleaning fluid used for cooling is returned to the cleaning fluid reservoir.In other words, within the scope of the present invention, cooling can take place when cleaning is not taking place, but the cleaning liquid is not consumed.

[0019] The cleaning fluid can generally be water with a cleaning agent additive and / or a coolant additive, for example so-called "wiping water". The cooling region can, for example, be a cooling surface on the surface of a housing of the sensor that is different from the cover and is specifically provided for cooling, so that, for example, a cooling plate can be exposed on the cooling surface with its outer side. However, within the scope of the present invention, it is also conceivable for the cooling region to extend at least partially into the interior of the sensor, which can then also have a housing, so that, for example, components of the sensor to be cooled can also be at least partially directly surrounded by the cleaning fluid as a cooling medium.

[0020] The sensor, which is preferably an environmental sensor, can in particular be an optical sensor, such as a camera and / or a lidar sensor. The sensor can be, for example, a so-called laser scanner. Especially with such laser scanners, it is known that cooling may be necessary at higher temperatures and / or in strong sunlight. However, cooling can also be useful for other types of sensors, such as radar sensors.

[0021] Within the scope of the present invention, it is fundamentally conceivable to provide a pump specifically assigned to the cooling circuit in order to convey the cleaning fluid through the cooling circuit and cool the sensor. However, a particularly advantageous embodiment of the present invention provides that the cleaning device further comprises an application arrangement for applying the cleaning fluid to the cover, comprising an application line section and a pump for conveying the cleaning fluid to the application arrangement, wherein the pump, which is designed in particular for continuous operation, is also designed to convey the cleaning fluid in the cooling circuit. In other words, the pump already provided for the cleaning function can also be used for the cooling circuit, for which purpose it is then expediently designed for continuous operation.In this context, a further development provides that the pump is arranged in a portion of the application line section that also belongs to the first line section of the cooling circuit, and that an adjusting means is provided downstream of the pump for selectively guiding at least a portion of the cleaning fluid into the remaining portion of the application line section and at least a portion of the cleaning fluid into the remaining portion of the first line section. The adjusting means can in particular be a valve and / or the adjusting means can comprise at least one valve. To expand the cleaning device to fulfill the cooling function, it is therefore only necessary to add the adjusting means, a portion of the first line section to the cooling area, and the second line section from the cooling area to the cleaning fluid reservoir, so that this embodiment can be implemented with particularly little effort and cost-effectively.

[0022] More generally speaking, the cleaning function can also be implemented in terms of control in a control unit of the sensor arrangement that is expanded in this regard and is already provided with regard to the cleaning function. For example, it is conceivable that the sensor and / or the sensor arrangement has a temperature sensor for measuring the temperature of the sensor, wherein a control unit of the sensor arrangement is designed to control the active circulation of the cleaning fluid through the cooling circuit as a function of temperature measurements from the at least one temperature sensor. For example, the control unit can be designed to initiate active cooling through the cooling circuit when a limit value for the temperature of the sensor is exceeded. For this purpose, the control unit can in particular be designed to control the pump and the actuating means accordingly.If, for example, a cleaning function is to be implemented, the pump can be operated briefly and the actuating device can be set so that the cleaning fluid is directed to the cover. If the cooling function is to be implemented, the pump can be controlled for more continuous operation and the actuating device can be set so that the cleaning fluid circulates through the cooling circuit. Intermediate states or complementary states are also conceivable, for example operating the pump more intensively for simultaneous cleaning and cooling and / or using part of the cleaning fluid for cleaning and part of the cleaning fluid for cooling, as long as the actuating device supports this. Generally speaking, a binary switching on and off of the cooling is conceivable and in many cases sufficient, making it easy to implement.However, in other embodiments it is also possible, for example, to provide different flow rates of the cleaning fluid by operating the pump at different speeds depending on the temperature of the sensor.

[0023] A filter for filtering the cleaning fluid can also be expediently provided in the cooling circuit, particularly in a portion of the first line section shared with the application line section. For example, larger particles that may be present in the cleaning fluid reservoir can be filtered out in this way, both to prevent contamination during the cleaning function and to prevent contamination in the cooling area of ​​the sensor as much as possible.

[0024] According to the invention, the cleaning device has a funnel-like collecting means in the second line section for the cleaning fluid flowing through the cooling area. Since the cooling area is not completely sealed, a corresponding funnel-like collecting means in the second line section is expediently provided where gravity then guides the cleaning fluid. In an embodiment not according to the invention, however, it is also conceivable in principle for the cooling section of the cooling circuit through which the cleaning fluid flows to cool the cooling area to be sealed off from the outside. In this embodiment not according to the invention, the pressure difference achieved by the pump or another conveying means in the cooling circuit is already sufficient to guide the cleaning fluid further into the second line section and from there back to the cleaning fluid reservoir.

[0025] According to the invention, the collecting means for transporting the cleaning fluid by gravity is arranged higher than the cleaning fluid reservoir. This allows the cleaning fluid flowing through the unsealed cooling section to be guided by gravity into the collecting means, from where it is in turn returned to the cleaning fluid reservoir by gravity, in a structurally simple and cost-effective manner.

[0026] In addition to the sensor arrangement, the present invention also relates to a motor vehicle comprising a sensor arrangement according to the invention, in particular installed on a windshield adjacent to a roof or on the roof. All statements regarding the sensor arrangement can be applied analogously to the motor vehicle according to the invention, with which the aforementioned advantages can also be achieved.

[0027] Further advantages and details of the present invention will become apparent from the exemplary embodiments described below and from the drawings. Fig. 1 a schematic view of a motor vehicle according to the invention, and Fig. 2 a schematic diagram of a sensor arrangement according to the invention.

[0028] Fig. 1 shows a schematic diagram of a motor vehicle 1 according to the invention. The motor vehicle 1 has, in an area of ​​its roof 2, in this case at the upper edge of a windshield 3, a sensor arrangement 4 with a sensor 5 whose detection range is directed toward the area in front of the motor vehicle 1. In this case, the sensor 5 is, for example, a laser scanner; however, other optical sensors and / or other sensors measuring through covers, for example radar sensors, are also conceivable. In general, the sensor 5 can be an environmental sensor.

[0029] Fig.Figure 2 shows the sensor arrangement 4 with the sensor 5 in more detail. The sensor 5 clearly has a housing 6, with the sensor data being recorded by a transparent cover 7, which can be formed, for example, by the windshield 3, but is implemented here as a separate cover 7 specifically provided on the sensor 5. The cover 7 can form or comprise a lens.

[0030] In order to be able to clean the cover 7 of dirt and the like, the sensor arrangement 4, in addition to the sensor 5, also has a cleaning device 8 for cleaning the cover 7. For this purpose, the cleaning device 8 comprises an application arrangement 9 with an application means 10, for example a nozzle, directed towards the cover 7 for a cleaning fluid 11, which is stored in a cleaning fluid reservoir 12. The cleaning fluid 11 can, for example, be water with a cleaning agent additive and / or an antifreeze additive. Such a cleaning fluid 11 is often also referred to as "washer water", so that the cleaning fluid reservoir 12 can also be connected to other cleaning devices of the motor vehicle 1, for example a windshield washer system and the like.

[0031] The application arrangement 9 has an application line section that connects the application means 10 to the cleaning fluid reservoir 12. In this case, the application line section has a first portion 13 and a second portion 14, wherein the first portion 13, in addition to a filter means 26, also contains a controllable pump 15 for conveying cleaning fluid from the cleaning fluid reservoir 12 through the filter means 26, which in particular comprises a particle filter, through the first portion 13. From there, the cleaning fluid flows through the second portion 14 of the application line section upon appropriate adjustment of a controllable actuating means 16 and can be applied to the cover 7 by means of the application means 10, cleaning it. The cleaning fluid 11 applied in this way can then, for example, run off over the windshield 3 and evaporate / be released into the environment.

[0032] Sensor 5 has a specific target operating temperature range, which is limited by a maximum permissible operating temperature. If the temperature exceeds the maximum permissible operating temperature, malfunctions or even damage to sensor 5 may occur. Since sensor 5 is arranged on the roof 2 or in the roof area of ​​motor vehicle 1, this can occur, for example, in sunlight.

[0033] To prevent overheating of the sensor 5, it should be cooled, which is why it has a cooling area 17, only indicated here, which is different from the cover 7. The cooling area 17 can, for example, be a cooling plate forming part of the outer surface of the housing 6, but can also provide for airflow around components of the sensor 5 inside the housing 6.

[0034] In order to avoid any safety risks that may arise when connecting to another cooling system of the motor vehicle 1 due to the proximity to the occupant, which is provided by the arrangement in the roof area, and to provide an easily implementable cooling option, the cleaning device 8 is additionally designed as a cooling device that uses the cleaning fluid 11 as the cooling medium. For this purpose, the cleaning device 8 has a cooling circuit formed by a first line section from the cleaning fluid reservoir 12 to the cooling area 17 and a second line section 18 from the cooling area 17 back into the cleaning fluid reservoir 12. So that the cooling circuit can also utilize the pump 15 and the filter medium 26, the first line section also has section 13 as its first portion, which it shares with the application line section.Thus, the first line section of the cooling circuit and the application line section extend together up to the adjusting means 16. Depending on the setting of the adjusting means 16, the cleaning fluid 11 is forwarded to the second portion 14 of the application line section for a cleaning process or to a second portion 19 of the first line section of the cooling circuit, so that the cleaning fluid reaches the cooling area 17. In exemplary embodiments, configurations of the adjusting means 16, which preferably comprises at least one valve, are also conceivable in which intermediate states can be set.

[0035] In principle, it is conceivable in an embodiment not according to the invention that the cooling section 20 located between the first line section (portions 13 and 19) and the second line section 18, passing through the cooling region 17, is sealed, for which purpose suitable sealing means can be used. Operation of the pump 15 then automatically pumps the cleaning fluid 11 further through the second line section 18. However, according to the invention, such a seal is dispensed with and a funnel-shaped collecting means 21 is used, which is located higher than the cleaning fluid reservoir 12, so that the cleaning fluid 11 is automatically returned through the second line section 18 into the cleaning fluid reservoir 12 due to gravity.In the present case, for example, the cleaning fluid reservoir 12 is arranged in the rear area of ​​the engine compartment of the motor vehicle 1, so that there is a significant difference in height to the sensor 5 anyway.

[0036] The operation of the sensor arrangement 4 is controlled by a control unit 22, which can be part of a control unit of the motor vehicle 1, but can also be specifically assigned to the sensor 5, for example, as a microchip. The control unit 22 can control the actuating means 16 and the pump 15 for a cleaning function such that cleaning fluid 11 is guided from the cleaning fluid reservoir 12 through the application line section (portions 13 and 14) to the application means 10, by which the cover 7 is cleaned.

[0037] The cooling function can be controlled, for example, based on the temperature measured by a temperature sensor 23. In this case, the temperature sensor 23 is provided as part of the sensor 5 within the housing 6, for example, on a relevant component of the sensor 5 and / or on the cooling area 17. If the measured temperature, i.e. the temperature measurement value, exceeds a limit value, which can be selected depending on the maximum permissible operating temperature, the control unit 22 controls the pump 15, which is also designed for continuous operation, and the actuating means 16 such that cleaning fluid 11 circulates from the cleaning fluid reservoir 12 in the cooling circuit formed by the first line section (portions 13 and 19), the cooling section 20, and the second line section 18.Since the cleaning fluid reservoir 12, which can also be assigned to other cleaning devices, is selected to be large, a sufficient amount of cool cleaning fluid 11 should be available.

[0038] Nevertheless, a cooler 25, designed in particular as a heat exchanger 24, can optionally be provided in the second line section 18, which cooler can be connected, for example, to ambient air, but also to another cooling circuit of the motor vehicle 1, which is possible due to the location of the cleaning fluid reservoir 12 in the engine compartment area. LIST OF REFERENCE SYMBOLS 1 motor vehicle 2 roof 3 Windshield 4 Sensor arrangement 5 Sensor 6 housings 7 Cover 8 Cleaning device 9 Application arrangement 10 application agents 11 Cleaning fluid 12 Cleaning fluid reservoir 13 Portion of the application line section 14 Portion of the application line section 15 Pump 16 setting agents 17 Cooling area 18 Second line section 19 Share of the first line section 20 Cooling section 21 Retention equipment 22 Control unit 23 Temperature sensor 24 heat exchangers 25 coolers 26 filter media

Claims

[1] Sensor arrangement (4) for a motor vehicle (1), comprising a sensor (5) with a cover (7) through which the sensor (5) detects information from its detection area, and a cleaning device (8) for cleaning the cover (7) with cleaning fluid (11) from a cleaning fluid reservoir (12), wherein the cleaning device (8), which is also designed as a cooling device, has a cooling circuit using the cleaning fluid (11) with a first line section from the cleaning fluid reservoir (12) to a cooling area (17) of the sensor (5) to be cooled, which cooling area is at least partially different from the cover (7), and a second line section (18) for returning the cleaning fluid (11) to the cleaning fluid reservoir (12), characterized bythat a cooling section (20) of the cooling circuit through which the cleaning liquid (11) flows to cool the cooling area (17) is not sealed, wherein the cleaning device (8) has a funnel-like collecting means (21) of the second line section (18) for the cleaning liquid (11) flowing through the cooling area (17), wherein the funnel-like collecting means (21) is arranged higher than the cleaning liquid reservoir (12) for transporting the cleaning liquid (11) by gravity. [2] Sensor arrangement (4) according to claim 1, characterized by that the cleaning device (8) further comprises an application arrangement (9) for applying the cleaning liquid (11) to the cover (7) with an application line section and a pump (15) for conveying the cleaning liquid (11) to the application arrangement (9), wherein the pump (15) is also designed to convey the cleaning liquid (11) in the cooling circuit. [3] Sensor arrangement (4) according to claim 2, characterized by that the pump (15) is arranged in a portion (13) of the application line section which also belongs to the first line section of the cooling circuit, and an adjusting means (16) for selectively guiding at least part of the cleaning liquid (11) into the remaining portion (14) of the application line section and at least part of the cleaning liquid (11) into the remaining portion (19) of the first line section is provided downstream of the pump (15). [4] Sensor arrangement (4) according to claim 3, characterized by that the adjusting means (16) is designed as a valve. [5] Sensor arrangement (4) according to one of claims 2 to 4, characterized by that the pump (15) is designed for continuous operation. [6] Sensor arrangement (4) according to one of the preceding claims, characterized by that a heat exchanger (24) for cooling the cleaning liquid (11) is arranged in the cooling circuit. [7] Sensor arrangement (4) according to claim 6, characterized by that the heat exchanger (24) is coupled to another coolant. [8] Sensor arrangement (4) according to one of the preceding claims, characterized by that the sensor (5) is a camera and / or a lidar sensor and / or a laser scanner and / or a radar sensor. [9] Motor vehicle (1) comprising a sensor arrangement (4) according to one of the preceding claims. [10] Motor vehicle (1) according to claim 9, characterized by that the sensor arrangement (4) is installed on a windshield (3) adjacent to a roof (2) or on the roof (2).

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