Sensor cleaning system with Anti-freezing function

Abstract

The present invention relates to a sensor cleaning system for a vehicle, and more specifically, to a sensor cleaning system having an anti-freezing and thawing function in an air injection type sensor cleaning system. According to an embodiment of the present invention, the sensor cleaning system for a vehicle comprises: an air tank in which compressed air is stored; a heating element provided in the air tank and configured to apply heat to the air tank; and a controller configured to operate the heating element when a preset condition is met.

Description

Technology Field

[0001] The present invention relates to a sensor cleaning system for a vehicle, and more specifically, to a sensor cleaning system having an anti-freezing and thawing function in an air injection type sensor cleaning system. Background Technology

[0002] Recently, vehicles are being equipped with driver assistance systems to support drivers in various driving situations, ensuring safe operation. Furthermore, going beyond these systems, active research and development is underway regarding autonomous vehicles capable of driving themselves without driver intervention.

[0003] In such driver assistance systems or autonomous vehicles, various types of environmental sensors capable of detecting the surrounding environment in diverse ways are installed. Examples of environmental sensors mounted on vehicles include radar, LiDAR, and cameras.

[0004] Since these sensors are mounted on the exterior of the vehicle, the sensing parts can easily become dirty due to foreign substances such as dust, rain, or snow. To maintain sensor performance, these sensors must be kept clean above a certain level, so vehicles are equipped with a sensor cleaning system that can clean the sensors when the sensing parts become contaminated. Prior art literature

[0005] Published Patent Application No. 10-2018-0136981 (Date of publication: Dec. 26, 2018) The problem to be solved

[0006] The present invention has been devised to solve the aforementioned problems, and

[0007] We aim to provide a sensor cleaning system that can prevent failures caused by freezing.

[0008] The objectives of the present invention are not limited to those mentioned above, and other unmentioned objectives will be clearly understood by those skilled in the art to which the present invention pertains (hereinafter referred to as "person skilled in the art") from the description below. means of solving the problem

[0009] The features of the present invention for achieving the objectives of the present invention as described above and for performing the characteristic functions of the present invention described below are as follows.

[0010] According to an embodiment of the present invention, a sensor cleaning system for a vehicle comprises: an air tank in which compressed air is stored; a heating element provided in the air tank and configured to apply heat to the air tank; and a controller configured to operate the heating element when a preset condition is met. Effects of the invention

[0011] According to the present invention, a sensor cleaning system capable of preventing failure caused by freezing is provided.

[0012] The effects of the present invention are not limited to those described above, and other unmentioned effects will be clearly recognized by a person skilled in the art from the description below. Brief explanation of the drawing

[0013] FIG. 1 illustrates a configuration diagram of an air cleaning system according to the present invention, and FIG. 2 illustrates a schematic layout of an air cleaning system in a vehicle, and FIG. 3 schematically illustrates a sensor cleaning system according to the present invention, and FIG. 4 illustrates a configuration diagram of a sensor cleaning system capable of preventing freezing according to the present invention, and FIG. 5 illustrates an air tank according to an embodiment of the present invention, and FIG. 6 is a partial enlarged view of FIG. 5, and FIGS. 7a to 11 illustrate control flow diagrams of a sensor cleaning system according to various embodiments of the present invention. Specific details for implementing the invention

[0014] The specific structural or functional descriptions presented in the embodiments of the invention are merely illustrative for the purpose of explaining embodiments according to the concept of the invention, and embodiments according to the concept of the invention may be implemented in various forms. Furthermore, it should not be interpreted as being limited to the embodiments described herein, but should be understood to include all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention.

[0015] Meanwhile, in the present invention, terms such as "first" and / or "second" may be used to describe various components, but said components are not limited to said terms. For the sole purpose of distinguishing one component from other components, for example, without departing from the scope of rights according to the concept of the present invention, the first component may be named the second component, and similarly, the second component may be named the first component.

[0016] When it is stated that one component is "connected" or "connected" to another component, it should be understood that while it may be directly connected or connected to that other component, there may also be other components in between. Conversely, when it is stated that one component is "directly connected" or "directly in contact" with another component, it should be understood that there are no other components in between. Other expressions used to describe the relationship between components, such as "between" and "exactly between," or "adjacent to" and "directly adjacent to," should be interpreted in the same way.

[0017] Throughout the specification, identical reference numbers denote identical components. Meanwhile, the terms used in this specification are for describing embodiments and are not intended to limit the invention. In this specification, the singular form includes the plural form unless specifically stated otherwise in the text. As used in this specification, "comprises" and / or "comprising" do not exclude the presence or addition of one or more other components, steps, actions, and / or elements to the mentioned components, steps, actions, and / or elements.

[0019] The present invention will be described in detail below with reference to the attached drawings.

[0020] As previously explained, periodic cleaning of the sensor surfaces is necessary to maintain the performance of environmental sensors that detect the vehicle's surrounding environment. For example, environmental sensors can be contaminated by foreign substances such as dust and sand, or by raindrops and snow during precipitation. In particular, in active autonomous vehicles, driving is performed based on surrounding environmental information, such as traffic lights, pedestrians, road types, buildings, and surrounding vehicles, which is perceived by environmental sensors. If the surface of the environmental sensor is contaminated by foreign substances, perception of the surrounding environment becomes impossible, and active autonomous driving becomes impossible. Therefore, the sensor cleaning system performs an important function of enabling driving by facilitating the environmental sensor's clear perception of the surrounding environment without distortion and by removing contaminants from the sensor surface.

[0021] Cleaning of these environmental sensors can be performed using washer fluid or high-pressure air. In the former, the sensor is cleaned using washer fluid, and moisture is removed from the sensor surface through air jets. In the latter, foreign matter on the sensor surface is removed by spraying only high-pressure air.

[0022] Let us examine the latter air cleaning case, in which an environmental sensor is cleaned by spraying air, with reference to FIG. 1. Among the sensor cleaning systems, the air cleaning system (1) is configured to clean the environmental sensor using compressed air. The air cleaning system (1) performs cleaning by spraying compressed air onto the surface of the environmental sensor (2). The environmental sensor (2) includes a sensing device such as a lidar, radar, or camera, and can be placed on the front, rear, side, roof, etc. of a vehicle.

[0023] Specifically, air filtered through an air filter (4) provided in the vehicle is introduced into a compressor (6). The air compressed by the compressor (6) is sprayed onto the surface of the environmental sensor (2), thereby removing foreign matter from the environmental sensor (2). The environmental sensor (2) includes a plurality of environmental sensors (2a, 2b, 2c), and although three environmental sensors are disclosed in the drawings and specifications, the number is not limited thereto and can be increased or decreased.

[0024] Additionally, the air cleaning system (1) includes an air tank (8). Air can be filled into the air tank (8) by compressed air through a compressor (6) or by an external device, and the air filled into the air tank (8) can be used to clean the environment sensor (2).

[0025] The controller (10) of the air cleaning system (1) is configured to operate the valve (12), for example, a solenoid valve, at preset intervals or in preset situations, such as when contamination is detected by the environment sensor (2). This causes compressed air to be sprayed from the compressor (6) or air tank (8) to each environment sensor (2), thereby cleaning the environment sensor (2). The valve (12) is equipped with or integrally formed with a distributor (14) so ​​that the compressed air can be distributed through nozzles (16) provided for each of the plurality of environment sensors (2).

[0026] The compressor (6) is equipped with a temperature sensing unit (17), and the temperature of the compressor (6) detected by the temperature sensing unit (17) is transmitted to the controller (10) of the air cleaning system (1). The controller (10) is configured to monitor the temperature of the compressor (130) so that the compressor (6) does not operate at an operating limit temperature. When the compressor (6) reaches the operating limit temperature, the controller (10) can control the operation of the compressor (6) to stop until the temperature of the compressor (6) drops.

[0027] Referring to FIG. 2, a compressor (6) and an air tank (8) can typically be provided in the front part of the vehicle. Air must be supplied from the compressor (6) and the air tank (8) provided in the front part of the vehicle to environmental sensors (16a, 16b, 16c) located in the front (F), side, roof (R), and rear (RR) of the vehicle. At this time, the air stored at high pressure in the air tank (8) passes through a hose with a small diameter and a very long length while undergoing a rapid pressure drop in the air tank (8) and the distributor (14). Air that undergoes a rapid pressure drop can easily reach the dew point and liquefy, or water molecules in the humid air can freeze as they are.

[0028] The hose may become clogged due to the freezing of condensation formed on the inner surface of the hose, and the nozzle (16) may become clogged due to the freezing of water droplets. Additionally, the inner surface of the pressure drop point of the air tank (8) and distributor (14) may become clogged due to the rapid sublimation of air and the freezing of moisture. In such cases, sensor cleaning becomes impossible, making autonomous driving difficult due to contamination of the environment sensor and potentially causing serious accidents.

[0029] In particular, if components such as nozzles and hoses become clogged due to freezing, self-diagnosis of faults and fail-safe operation become impossible, causing the system to shut down immediately and rendering autonomous driving impossible. Additionally, aluminum is often used for air tanks to achieve lightweight design and high-pressure resistance. In this case, the rapid pressure drop during air injection causes the temperature to fall, and as the surface temperature becomes very low, the tank tends to be more vulnerable to freezing.

[0030] Accordingly, the present invention aims to provide an air cleaning system having a freezing prevention and removal function. By solving the problem of freezing caused by a sudden drop in pressure, it prevents blockage of hoses and nozzles due to freezing, thereby preventing accidents that may occur while driving, especially during autonomous driving.

[0031] As illustrated in FIGS. 3 and 4, the air cleaning system (1) according to the present invention includes a heating element (20). In one embodiment, the heating element (20) is placed in an air tank (8). Referring to FIG. 5, in one embodiment, the heating element (20) may be placed around the inlet (18) and outlet (28) of the air tank (8), respectively. The heating element (20) can generate heat by an applied voltage, thereby preventing condensation formation and freezing in the air tank (8), particularly in the inlet (18) and outlet (28) of the air tank (8).

[0032] As a non-limiting example, the heating element (20) may be a heat pad. The outer shell and heating wire of the heat pad may be made of non-woven fabric or nichrome wire. Furthermore, the materials are not limited to these, and other possible known materials may be used. However, a material with sufficient vibration resistance and heat resistance is selected. According to the present invention, various types of heating elements (20) may be applied. As one non-limiting example, the heating element (20) may be a linear heating element. A linear heating element is a heating element with a series structure utilizing nickel, iron-chromium wire, etc. As another non-limiting example, the heating element (20) may be a planar heating element. For example, as a planar heating element, an ITO (Indium Tin Oxide) film, a metal mesh film, a transparent planar heating element film, a PTC (Positive Temperature Coefficient) heating film, a far-infrared heating film, etc. may be applied. However, the materials are not limited thereto, and applicable known heating elements may be used.

[0033] Referring again to FIG. 3, the air cleaning system (1) may further include a heating hose (22). The air passage of the air cleaning system (1) may be formed by the heating hose (22). The heating hose (22) may also be operated by an applied voltage, similar to the heating element (20). Typically, because air hoses have a very small diameter and a long length, freezing is likely to occur on the air hose due to a sudden drop in pressure caused by the discharge of high-pressure air to atmospheric pressure and very low ambient temperatures. Accordingly, the present invention can raise the temperature of the air and prevent freezing during air flow by forming the air passage with the heating hose (22).

[0034] Referring again to FIG. 5, the air tank (8) may be equipped with a drain valve (26). The drain valve (26) enables the discharge of water formed in the air tank (8) due to the operation of the heating element (20). In one embodiment, the drain valve (26) is a solenoid valve.

[0035] Referring again to FIG. 4, according to some embodiments of the present invention, an air tank (8) may be equipped with a water level sensor (34). The water level sensor (34) is configured to detect the water level formed within the air tank (8). The water level information may serve as a basis for determining the opening of the drain valve (26). As a non-limiting example, the water level sensor may be a float switch, a non-contact ultrasonic level sensor, a contact ultrasonic level sensor, a capacitive level sensor, a radar level sensor, or a paddle flow switch, but is not limited thereto.

[0036] Referring to FIG. 6, a temperature sensor (24) is provided in the air tank (8). The temperature sensor (24) may be provided around the inlet (18) and the outlet (28), respectively. In particular, the temperature sensor (24) is configured to measure surface temperature information of the air tank (8). The measurement value of the temperature sensor (24) can serve as a basis for determining the operation of the heating element (20) and the heating hose (22).

[0037] The controller (10) receives the temperature detected by the temperature sensor (24). The controller (10) is configured to operate the heating element (20) and the heating hose (22) based on the measured temperature. When voltage is applied to the heating element (20) and the heating hose (22) according to the controller's (10) determination of whether heating is required, heat generation occurs according to the physical properties of the heating wire.

[0038] Additionally, the controller (10) can operate the drain valve (26) when a preset condition is satisfied. If the drain valve (26) is a solenoid valve, the controller (10) applies voltage to the solenoid coil when the drain valve (26) is opened so that the drain valve (26) is opened. For example, the controller (10) can determine the opening of the drain valve (26) based on the vehicle state, such as the vehicle's autonomous driving mode being turned off or the engine being turned off. Additionally, the controller (10) may open the drain valve (26) based on the water level inside the air tank (8) measured by the water level sensor (34).

[0039] Referring to FIGS. 7a to 11, a control method for an air cleaning system having an anti-freezing function according to the present invention will be described.

[0040] As illustrated in FIG. 7a, the controller (10) receives the vehicle's ignition being turned on (S1). When the ignition is turned on, the temperature sensor (24) continuously detects the temperature of the air tank (8), and the controller (10) collects the temperature of the air tank (8) from the temperature sensor (24). Then, the controller (10) determines whether the collected temperature of the air tank (8) is lower than a preset value (S3). Here, the preset value may be 0 degrees Celsius, but it may be changed depending on the situation. If it is determined that the temperature of the air tank (8) is lower than the preset value, the controller (10) activates the heating element (20) (S5). Here, the activation of the heating element (20) also refers to the activation of the heating hose (22). The same applies below, but for simplification, it will be referred to as the heating element (20). Accordingly, the surface temperature of the air tank (8) can be raised by the operation of the heating element (20) and the heating hose (22) to prevent freezing or to perform thawing. While operating the heating element (20), the controller (10) continuously receives temperature information from the temperature sensor (24) to determine whether the temperature of the air tank (8) reaches a preset allowable value (S7). When the temperature of the air tank (8) exceeds the allowable value, the controller (10) stops applying voltage to the heating element (20) and stops the operation of the heating element (20) (S9). As a non-limiting example, the allowable value may be 10 degrees Celsius. However, this allowable value may be changed depending on the use.

[0041] According to the present invention, the basis for determining the operation of the heating element (20) may be modified to reduce power consumption and increase system durability. According to some embodiments, as shown in FIG. 7b, the controller (10) may also use ambient temperature information as the basis for determining the operation of the heating element (20) (S3'). When the temperature of the air tank (8) and the ambient temperature are below a set value, the controller (10) may operate the heating element (20). Additionally, as shown in FIG. 7c, according to some embodiments of the present invention, the controller (10) may use whether the autonomous driving function of the vehicle is turned on as the basis for determining the operation of the heating element (20). The controller (10) determines whether the autonomous driving mode is turned on so that the heating element (20) operates only when the autonomous driving mode requires sensor cleaning (S2). Then, the operation of the heating element (20) may be determined based on the temperature of the air tank (8). The following steps are the same as those in FIG. 7a, so a redundant description is omitted.

[0042] As illustrated in FIG. 8, according to some embodiments of the present invention, the controller (10) can determine whether to operate the heating element (20) based on external conditions, i.e., the operating status of other systems within the vehicle, without determining whether the temperature of the air tank (8) measured by the temperature sensor (24) is below an allowable value (S4). For example, when a specific thawing system is operated to prevent failure due to freezing in another controller within the vehicle, the controller (10) can determine the operation of the heating element (20) according to the signal. To this end, the controller (10) may be configured to communicate with the controller of another system that performs thawing within the vehicle.

[0043] According to some embodiments of the present invention, the air cleaning system (1) can determine a failure of the air cleaning system (1) caused by freezing and correct it. As illustrated in FIG. 9a, when the vehicle is started (S1), the controller (10) determines whether the autonomous driving mode is turned on (S2). When the autonomous driving mode is turned on and the controller (10) opens the valve (12) for sensor cleaning, the controller (10) observes the pressure change of the distributor (14). The controller (10) determines whether the pressure change of the distributor (14) is less than a preset minimum value (S12). Even if an opening command is issued to the valve (12), if there is no pressure change of the distributor (14), blockage due to freezing can be predicted. In this case, the controller (10) determines that blockage due to freezing has occurred and operates the heating element (20) to perform thawing.

[0044] Additionally, the controller (10) can determine the possibility of freezing based on weather conditions (S14). For example, the controller (10) can collect rainfall information and ambient temperature information and determine with a higher probability of blockage due to freezing when there is no rainfall and the ambient temperature is below zero. That is, even if an opening command is issued to the valve (12) but the pressure change of the distributor (14) is below the minimum value and there is a possibility of freezing based on weather conditions, the controller (10) can operate the heating element (20) (S16).

[0045] As illustrated in FIG. 9b, according to some embodiments of the present invention, the controller (10) may use information from another controller as a basis for determining whether freezing has occurred. When the autonomous driving mode is turned on (S2), the controller (10) receives input of a failed attempt at sensor cleaning from the autonomous driving controller of the autonomous driving system (S13). For example, there may be a case where the autonomous driving controller issues a cleaning command to the controller (10) of the sensor cleaning system, but the sensor cleaning is not performed due to blockage caused by freezing. The autonomous driving controller informs the controller (10) that cleaning was not performed despite several attempts to execute sensor cleaning, and the controller (10) can determine whether the air cleaning system (1) has frozen based on this information. Additionally, the controller (10) can operate the heating element (20) (S19) to eliminate freezing when there is a possibility of freezing due to weather conditions (such as when there is no rainfall and the outside temperature is below zero) (S15) and when the pressure change of the distributor (14) is also below the minimum value (S17).

[0046] As shown in FIGS. 10a to 11, the controller (10) can determine the operation of the drain valve (26) based on preset conditions.

[0047] Referring to FIG. 10a, according to some embodiments of the present invention, a controller (10) may open a drain valve (26) when the autonomous driving mode is off or the vehicle's engine is off (S30). When the autonomous driving mode or the engine is off, the controller (10) opens the drain valve (26) (S32). The controller (10) determines whether the open time of the drain valve (26) has reached a preset time (S34). The preset time may be a pre-selected value at which drainage can be completed. When the open time reaches the preset time, the controller (10) closes the drain valve (26) (S36).

[0048] As illustrated in FIG. 10b, according to some embodiments of the present invention, in an air cleaning system equipped with an initialization function, a drain valve (26) can be operated depending on whether initialization is performed. The initialization function is a process of regenerating a dryer, which is a component within a compressor (6) configured to adsorb moisture contained in the outside air when the outside air is compressed, and when the cleaning function is not performed, the compressor (6) is driven in the reverse direction to exhaust from the air tank (8). In a system having such an initialization function, a controller (10) collects information regarding whether the initialization function is activated (S40). During the execution of initialization, the controller (10) determines whether the pressure inside the air tank (8) reaches a set pressure, for example, less than 1 bar (S42). In one embodiment, the pressure inside the air tank (8) can be determined based on the measurement of a pressure sensor provided in the air tank (8), and when the pressure reaches the set pressure, it can be determined that the initialization is completed. Then, when the pressure of the air tank (8) becomes less than the set pressure, the controller (10) opens the drain valve (26) (S44) and maintains the open state of the drain valve (26) for a set time (S46). When the set time has elapsed, the controller (10) closes the drain valve (26) to end the drainage (S48). In this embodiment, drainage can be performed for a certain period of time after the air in the air tank (8) is discharged during the initialization process.

[0049] According to some embodiments of the present invention, the opening of the drain valve (26) may be performed based on the input of the water level sensor (34). Referring to FIG. 11, the controller (10) receives water level information in the air tank (8) measured by the water level sensor (34). When the autonomous driving mode ends or the engine starts (S30), the controller (10) determines whether the input water level of the air tank (8) exceeds a preset minimum water level (S50). For example, the minimum water level may be 5% of the height of the air tank (8). If the input water level of the air tank (8) exceeds the minimum water level, the controller (10) opens the drain valve (26) (S52). The controller (10) determines whether the drainage is completed (S54), and if it is completed, closes the drain valve (26) (S56). The completion of drainage can be exemplified by the case where the water level of the air tank (8) input from the water level sensor (34) is 0.

[0050] According to the present invention, failure of the air cleaning system can be prevented in advance.

[0051] The air cleaning system according to the present invention can be implemented by utilizing the addition and modification of some components and control logic without major package changes.

[0052] The air cleaning system according to the present invention can diagnose a malfunction caused by freezing and clear the freezing.

[0053] The present invention described above is not limited by the aforementioned embodiments and attached drawings, and it will be obvious to those skilled in the art that various substitutions, modifications, and changes are possible within the scope of the technical concept of the present invention. Explanation of the symbols

[0054] 1: Air cleaning system 2: Environmental sensor 4: Air filter 6: Compressor 8: Air tank 10: Controller 12: Valve 14: Distributor 16: Nozzle 17: Temperature sensor 18: Inlet 20: Heating element 22: Heating hose 24: Temperature sensor 26: Drain valve 28: Discharge port 34: Water level sensor

Claims

Claim 1 A sensor cleaning system for a vehicle comprising: an air tank in which compressed air is stored; a heating element provided in the air tank and configured to apply heat to the air tank; a heating hose connected to the air tank so that the compressed air flows through the heating hose and configured to generate heat; and a controller configured to operate the heating element when a preset condition is met. Claim 2 A system according to claim 1, further comprising a temperature sensor disposed in the air tank and configured to detect the temperature of the air tank and transmit it to the controller. Claim 3 A system according to claim 2, wherein the controller is configured to operate the heating element based on the temperature of the air tank received from the temperature sensor. Claim 4 A control method for a system according to claim 2, wherein the controller is configured to perform the steps of: receiving the temperature of the air tank from the temperature sensor; and operating the heating element when the temperature of the air tank is less than a preset value. Claim 5 A control method according to claim 4, wherein the controller is configured to perform the steps of: continuously receiving the temperature of the air tank from the temperature sensor after the operation of the heating element; and stopping the operation of the heating element when the temperature of the air tank exceeds a preset allowable value. Claim 6 A control method according to claim 5, wherein the controller is configured to perform the step of operating the heating element when the temperature of the air tank and the ambient temperature are below a set value. Claim 7 A control method for a system according to claim 2, wherein the controller is configured to perform: a step of determining whether the autonomous driving mode of the vehicle is in an ON state; and a step of operating the heating element when the autonomous driving mode of the vehicle is in an ON state and the temperature of the air tank received from the temperature sensor is less than a set value. Claim 8 A system according to claim 2, further comprising a drain valve provided in the air tank and configured to discharge a fluid contained within the air tank. Claim 9 A system according to claim 8, wherein the controller is configured to control the operation of the drain valve. Claim 10 A system according to claim 9, further comprising a water level sensor configured to detect the water level in the air tank and configured to transmit the detected water level to the controller. Claim 11 A control method for a system according to claim 9, wherein the controller is configured to perform the steps of: determining whether the autonomous driving mode of the vehicle is in an off state or whether the engine of the vehicle is in an off state; and, if the autonomous driving mode of the vehicle or the engine is in an off state, opening the drain valve for a preset time. Claim 12 A control method for a system according to claim 10, wherein the controller is configured to perform the steps of: determining whether the autonomous driving mode of the vehicle is in an off state or the engine of the vehicle is in an off state; determining whether the water level detected by the water level sensor exceeds a preset minimum water level when the autonomous driving mode of the vehicle or the engine is in an off state; and opening the drain valve when the water level of the air tank exceeds the minimum water level. Claim 13 A system according to claim 1, comprising: a compressor that generates the compressed air and is connected to the inlet of the air tank; and a distributor connected to the outlet of the air tank and for receiving and distributing the compressed air from the air tank. Claim 14 A system according to claim 13, wherein the heating hose comprises a first heating hose and a second heating hose, the compressor and the air tank are connected by the first heating hose, and the air tank and the distributor are connected by the second heating hose. Claim 15 A system according to claim 1, wherein the controller is configured to control the operation of the heating hose. Claim 16 A system according to claim 13, wherein the controller is configured to control the operation of a valve for opening and closing the distribution flow of the distributor. Claim 17 A system according to claim 16, wherein the controller is configured to operate the heating element when the pressure change of the distributor is less than a preset minimum value when the valve is opened. Claim 18 A system according to claim 14, wherein the controller is configured to operate the heating element when the ambient temperature and rainfall amount satisfy preset conditions when the heating element is operated.

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