SYSTEM AND METHOD FOR DEFROSTING A REAR WINDOW OF A VEHICLE

Abstract

A system (100) for defrosting a vehicle's rear window comprises one or more sensor units (102) attached to or near the rear window to detect the dew point of the air and the fog level on the rear window. A control unit (104), communicatively coupled to the one or more sensor units (102), is configured to receive the detected dew point and fog level on the rear window and, based on this information, determines a fog index indicating the degree of obstructed visibility through the rear window. Furthermore, the control unit (104) is configured, based on the fog index, to control the speed of a blower (116) of a defrosting unit (106), which is configured to direct an airflow toward the rear window to defog it.

Description

TECHNICAL AREA

[0001] The present disclosure relates to the technical field of motor vehicles. In particular, the present disclosure relates to a system and method for defrosting a rear window of a vehicle, which optimizes performance utilization while simultaneously ensuring sufficient visibility through the rear window. BACKGROUND

[0002] The background description contains information that may be useful for understanding the present invention. It does not constitute an admission that the information contained herein forms part of the prior art or is relevant to the present invention, or that any publication to which express or implicit reference is made forms part of the prior art.

[0003] Fog or condensation on a vehicle's windshield impairs visibility, making it difficult for the driver to see the road, other vehicles, pedestrians, and other potential hazards. Driving with a fogged-up windshield can therefore be tiring, distracting, and even dangerous. To counteract this, various defogging systems are typically implemented to ensure drivers have clear visibility, thus contributing to a more comfortable driving experience and greater safety.

[0004] Conventional rear window defogging systems rely on electric resistance heating to remove fog from the rear window. However, these systems consume a significant amount of electrical energy, which can place a heavy load on the vehicle's electrical system. This impacts fuel efficiency in vehicles with conventional combustion engines and reduces the vehicle's range and battery life in electric vehicles. Furthermore, resistance heating systems can take some time to reach the required temperature for effective fog removal, delaying the achievement of clear visibility.

[0005] Therefore, from the point of view of user comfort and safety, it would be advantageous to have a system that maintains visibility while driving and simultaneously optimizes energy use.

[0006] Patent specification US7392838B2 discloses a system and a method for calculating and controlling the defogging state of a vehicle in order to automatically defog a windshield and prevent fogging or misting of the windshield. The ambient air temperature and vehicle speed are measured and used to determine the windshield temperature. The interior air temperature and relative humidity are measured and used to determine the dew point. A dew point margin is calculated to compensate for sensor accuracy and the predictability of fog formation.A fog range, based on the calculated windscreen temperature and dew point, is calculated and used in conjunction with the dew point range to control the HVAC system so that it can anticipate potential fogging conditions and scale the intensity of the HVAC system's response based on the severity of the fogging conditions.

[0007] While the cited reference reveals the automatic defogging of a windshield, there is the possibility of providing a further improved system and procedure that overcomes the aforementioned problems.

[0008] Therefore, there is a need to provide an improved and efficient system and method for defrosting a vehicle's rear window that can ensure optimal utilization of the power source's output while maintaining sufficient visibility during driving. OBJECTIVITY OF INVENTION

[0009] A general purpose of this disclosure is to improve the driving experience and safety in a vehicle.

[0010] One purpose of the present disclosure is to improve the view through a vehicle's rear protective window in order to facilitate driving and ensure safety.

[0011] One objective of the present disclosure is to provide a system and a method for automatically defrosting a vehicle's rear windscreen in order to ensure a clear view to the rear while driving.

[0012] One purpose of the present disclosure is to provide a system and method that regulates energy consumption when there is sufficient visibility through a rear protective window. SUMMARY

[0013] Aspects of the present disclosure relate to defrosting a rear window of a vehicle with the aim of enabling the driver to have a clear view to the rear while driving, while reducing power consumption in order to increase the vehicle's range.

[0014] According to one aspect, the proposed system for defrosting a vehicle's rear window comprises one or more sensor units attached to or near the rear window to detect the dew point of the air and the fog level of the rear window. The system includes a control unit that is communicatively coupled to the one or more sensor units. The control unit is configured to receive the detected dew point and fog level of the rear window. Furthermore, the control unit is configured to determine a fog index based on the detected dew point and fog level of the rear window, with the fog index indicating the degree of impaired visibility through the rear window.Furthermore, the control unit is configured to control the speed of a blower of a defrosting unit based on the fog index, which is configured to direct an airflow towards the rear window in order to defog the rear window.

[0015] In one or more embodiments, the one or more sensor units can include one or more dew point sensors. The one or more dew point sensors can be configured to monitor the humidity and temperature of the air near the rear window, and the control unit can determine the dew point based on the monitored humidity and temperature of the air and thereby calculate a probability of the rear window fogging up.

[0016] In one or more embodiments, the one or more sensor units can comprise a set of light intensity sensors. The set of light intensity sensors can be configured to determine the loss of light intensity as light passes through the windshield, the extent of which can be related to the fogging state of the windshield.

[0017] In one or more embodiments, if the detected loss of light intensity exceeds a predefined threshold, it can be concluded that the windshield is beginning to fog up, and the control unit can activate the defrosting unit.

[0018] In one or more embodiments, the system can include a hydrophobic material with which a surface of the rear window is coated to impart water-repellent properties to the surface of the windshield. The hydrophobic material can be selected from the group consisting of: silicon dioxide nanocoating, manganese oxide polystyrene, zinc oxide polystyrene, precipitated calcium carbonate, carbon nanotube structures, fluorinated silanes, and fluoropolymer coatings.

[0019] In one or more embodiments, the de-icing unit may include a heat pump for recovering waste heat from the cooling system of a battery pack or a drive motor of the vehicle or both systems.

[0020] In one or more embodiments, the light intensity sensor may comprise two or more transmitters arranged on an outer surface of the rear window. Each of the two or more transmitters may be located at an upper corner of the rear window to emit light. Furthermore, the light intensity sensor may comprise two or more receivers arranged on an inner surface of the rear window. Each of the two or more receivers may be positioned at a lower corner to receive the light emitted through the rear window from the diagonally opposite transmitters. The control unit may be connected to the two or more transmitters and the two or more receivers to determine the loss of light intensity as the light passes through the rear window.

[0021] In one or more embodiments, the one or more dew point sensors can comprise a plurality of capacitive sensors. Each of the multiple capacitive sensors can comprise a substrate base layer, a lower electrode, a middle layer, and an upper electrode. The middle layer can be a hygroscopic metal oxide or polymer layer, and the upper electrode can be a water-permeable electrode.

[0022] In one or more embodiments, the control unit can be configured to determine a heating period, based on the determined fog index, for which the rear window can be heated, and to control the operation of the blower accordingly.

[0023] Another aspect of the present disclosure is the method described herein for defrosting a vehicle's rear window. The method comprises detecting the dew point of the air and the fog level of the rear window using one or more sensor units. The method includes receiving the detected dew point and fog level of the rear window by a control unit. Furthermore, the method comprises determining a fog index at the control unit based on the detected dew point and fog level of the rear window, the fog index being an indicator of the degree of impaired visibility through the rear window.Furthermore, the procedure includes controlling, based on the fog index, the speed of a blower of a defrosting unit configured to direct an airflow towards the rear window to defog the rear window, the defrosting unit being configured to recover waste heat from a cooling system of a battery pack or a drive motor of the vehicle, or both.

[0024] Various objects, features, aspects and advantages of the subject matter according to the invention will become clearer from the following detailed description of preferred embodiments together with the accompanying drawing figures, in which the same numbers represent the same components. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings serve to further understand the present disclosure and are an integral part of this description. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure. Fig. Figure 1 shows an exemplary block diagram of the proposed system for defrosting a rear window of a vehicle according to one or more embodiments of the present disclosure. Fig. 2A and Fig. Figure 2B shows a front view and a side view illustrating the arrangement of one or more transmitters and one or more receivers of a set of light intensity sensors. Fig. 1 on the rear protective window of a vehicle according to one or more embodiments of the present disclosure. Fig. Figure 3 shows an exemplary flowchart for the proposed method for defrosting a rear window of a vehicle according to one or more embodiments of the present disclosure. DETAILED DESCRIPTION

[0026] A detailed description of the embodiments of the disclosure illustrated in the accompanying drawings follows. The embodiments are described in sufficient detail to clearly convey the disclosure. However, the necessary level of detail is not intended to limit foreseeable variations of the embodiments; on the contrary, it is intended to cover all modifications, equivalents, and alternatives that fall within the spirit and scope of the present disclosure as defined by the accompanying claims.

[0027] The embodiments described herein relate to the field of motor vehicles. In particular, the present disclosure relates to a system and a method for defrosting a rear windshield of a vehicle.

[0028] In one aspect, the proposed system enables automatic defrosting of the rear window with optimized energy consumption by regulating the speed of a fan depending on the intensity of the fog. Another aspect is that the proposed system uses recovered heat for defrosting the rear window, instead of relying on electrical power from the battery pack as is currently the case. This also helps to maximize the vehicle's range when used in electric vehicles.

[0029] With reference to Fig. A system 100 for defrosting a vehicle's rear windshield is presented. The system 100 comprises one or more sensor units 102 and a control unit 104. The one or more sensor units 102 are attached to or near the rear windshield to detect the dew point of the air and the fogging condition of the windshield. The one or more sensor units 102 can contain one or more dew point sensors 108. The one or more dew point sensors 108 can be configured to monitor the humidity and temperature of the air near the rear windshield. The control unit can determine the dew point in real time based on the monitored humidity and temperature of the air and calculate the probability of fogging of the rear windshield.

[0030] Furthermore, one or more sensor units 102 can contain a set of light intensity sensors 110. The set of light intensity sensors 110 can be configured to determine the loss of light intensity as light passes through the rear window, whereby the extent of the loss of light intensity can be related to the fogging state of the rear window.

[0031] In one embodiment, the system 100 comprises the control unit 104, which is communicatively coupled to one or more sensor units 102. The control unit 104 is configured to receive the detected dew point and the fog level of the rear window. Furthermore, the control unit 104 is configured to determine a fog index based on the detected dew point and the fog level of the rear window, the fog index being a measure of the degree of restricted visibility through the rear window. In addition, the control unit 104 is configured to control the speed of a blower 116 of a defrosting unit 106 based on the fog index. The blower is configured to direct an airflow to the rear window to defog the rear window.For example, if the detected loss of light intensity exceeds a predefined threshold, it can be concluded that the rear window is beginning to fog up, and the control unit 104 can activate the blower 116 of the defrosting unit 106. The defrosting unit 106 may contain a heat pump 118 for recovering waste heat from the cooling system of a battery pack or a drive motor of the vehicle, or both. In other cases, if the detected intensity loss falls below the predefined threshold, it can be concluded that the rear window is clear, and the control unit 104 can deactivate the blower 116, thus optimizing the energy consumed by the blower 116.

[0032] In one or more embodiments, the control unit 104 can continue to operate the blower 116, depending on the determined fog index, even if the determined intensity loss is below the predefined threshold, e.g., if the fog index indicates that fog is likely to form again on the windshield, thus preventing fog formation on the windshield. The control unit 104 can also regulate the speed of the blower 116 depending on the determined fog index in order to optimize energy consumption.

[0033] In one embodiment, the control unit 104 can also be configured to determine a heating time duration for which the rear window can be supplied with heat, based on the determined fog index, and to control the operation of the blower 116 accordingly.

[0034] In one embodiment, the fog index can be calculated using the following formula: Tcabin−TDew Point=X0 where X0 ≤ 0, Tcabin the vehicle's cabin temperature and TDew Point The dew point temperature of the air. Iv Transmitted−Iv Received=FI[XXX]1,2,3 where, I v Transmitted is the luminous intensity of the transmitted light source - scaled to 100 XXX 1, 2, 3 These are custom configurations of the atomization index for the control unit.

[0035] In one embodiment, the control unit 104 can be implemented as one or more microprocessors, microcomputers, microcontrollers, edge or fog microcontrollers, digital signal processors, central processing units, logic circuits, and / or any device for processing data based on operating instructions. Among other capabilities, the processor can be configured to retrieve and execute computer-readable instructions stored in a memory of the system 100. The memory can be configured to store one or more computer-readable instructions or routines on a non-volatile, computer-readable storage medium, which can be retrieved and executed to detect the dew point of the air and the fog state of the rear window using one or more sensor units 102. The memory can comprise any non-volatile device, e.g.,volatile memory such as Random Access Memory (RAM) or non-volatile memory such as Erasable Programmable Read-Only Memory (EPROM), Flash memory, and the like.

[0036] In one embodiment, the system 100 can include a hydrophobic material with which a surface of the rear window is coated to impart water-repellent properties to the windshield surface. The hydrophobic material can be selected from, but is not limited to, a group consisting of: silicon dioxide nanocoating, manganese oxide polystyrene, zinc oxide polystyrene, precipitated calcium carbonate, carbon nanotube structures, fluorinated silanes, and fluoropolymer coatings. The hydrophobic coating can repel water and reduce the adhesion of contaminants, thereby improving visibility and reducing the frequency of windshield cleaning. The coating can form a thin, transparent layer that interacts with water and other liquids, causing them to bead up and roll off the surface more easily.

[0037] Referring to Fig. 2A and Fig. In one embodiment, the light intensity sensor 110 can comprise two or more transmitters 112-1, 112-2 (here collectively referred to as transmitters 112) arranged on an outer surface of the rear window. Each of the two or more transmitters 112 can be positioned at an upper corner section of the rear window to emit light. Furthermore, the light intensity sensor 110 can comprise two or more receivers 114-1, 114-2 (here collectively referred to as receivers 114) arranged on an inner surface of the rear window. Each of the two or more receivers 114-1, 114-2 can be positioned at a lower corner section to receive the light emitted through the rear window from the diagonally opposite transmitters 112. The control unit 104 can be used to couple with the transmitters 112 and the receivers 114 to determine the loss of light intensity as the light passes through the rear window.

[0038] Furthermore, the one or more dew point sensors 108 can comprise a variety of capacitive sensors. Each of the multiple capacitive containers can include a substrate base layer, a lower electrode, a middle layer, and an upper electrode. The middle layer can be a hygroscopic metal oxide or polymer layer, and the upper electrode can be a water-permeable electrode.

[0039] With reference to Fig. Section 3 discloses the proposed method 300 for defrosting a vehicle's rear window. The method 400 can operate on the basis of one or more sensor units attached to or near the rear window to detect the dew point of the air and the fogging status of the rear window, as well as on the basis of a control unit 104 that is communicatively coupled to the one or more sensor units 102. The other elements for carrying out the method 300 can be a defrosting unit 106, a heat pump 118, and other components connected to the system 100, as shown in Fig.Figure 1 shows. Method 300 can include step 302 of detecting the dew point of the air and the fog state of the rear window using one or more sensor units 102. Method 300 can further include step 304 of receiving the detected dew point and fog state of the rear window by a control unit 104. In addition, Method 300 can include step 306, in which the control unit 104 determines a fog index based on the detected dew point and fog state of the windshield, the fog index being an indicator of the degree of impaired visibility through the rear window.Method 300 may include step 308, in which, based on the fog index, the speed of a blower 116 of a defrosting unit 106 is controlled, the defrosting unit being configured to direct an airflow towards the rear window to defog the rear window, the defrosting unit 106 being configured to recover waste heat from a cooling system of a battery pack or a drive motor of the vehicle, or from both.

[0040] As can be seen, the proposed solution overcomes the problems associated with conventional, resistance-heating-based defogging systems, such as the delay in achieving visibility, the limited detection range, and the significant consumption of electrical energy. The proposed solution utilizes heat recovered from the cooling system of a battery pack or the vehicle's drive motor by a heat pump 118 and the application of a hydrophobic coating to the rear window on both sides.

[0041] While the foregoing describes various embodiments of the invention, other and further embodiments of the invention can be developed without deviating from the fundamental scope of the invention. The scope of the invention is defined by the following claims. The invention is not limited to the described embodiments, variants, or examples, provided that they are included to enable a person with ordinary technical knowledge to manufacture and use the invention when combined with information and knowledge available to such a person. ADVANTAGES OF THE INVENTION

[0042] The system and method described in this disclosure improve the driver experience and safety in a vehicle.

[0043] The system and method of the present disclosure improves the view through the rear protective window of a vehicle to facilitate driving and ensure safety.

[0044] The present disclosure provides a system and a method for automatically defrosting a vehicle's rear windshield to ensure a clear view to the rear while driving.

[0045] The system and method of the present disclosure provides a system and method that regulates energy consumption when there is sufficient visibility through a rear protective window. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] US 7392838B2

[0006]

Claims

[1] System (100) for defrosting a rear window of a vehicle, the system (100) comprising: one or more sensor units (102) attached to or near the rear window to detect the dew point of the air and the fogging condition of the windscreen; and a control unit (104) that is communicatively coupled to one or more sensor units (102), wherein the control unit (104) is configured to: received the detected dew point and the fog level of the rear window; to determine a fog index based on the collected dew point and the fog state of the rear window, the fog index indicating the degree of impaired visibility through the rear window; and to control the speed of a blower 116 of a defrosting unit (106) based on the fog index, which is configured to direct an airflow to the rear window to defog the windscreen. [2] System (100) according to claim 1, wherein the one or more sensor units (102) comprise one or more dew point sensors (108) configured to monitor the humidity and temperature of the air near the windshield, and wherein the control unit determines the dew point based on the monitored humidity and temperature of the air and calculates a probability of fogging of the rear window. [3] System (100) according to claim 1, wherein the one or more sensor units (102) comprise a set of light intensity sensors (110) configured to determine the loss of light intensity when light passes through the rear window, and wherein the extent of the loss of light intensity is related to the fog state of the rear window. [4] System (100) according to claim 3, wherein the detected loss of light intensity exceeds a predefined threshold, it is concluded that the windshield is beginning to fog up and the control unit (104) activates the de-icing unit (106). [5] System (100) according to claim 1, comprising a hydrophobic material with which the surface of the rear window is coated to give the surface of the rear window a water-repellent property, wherein the hydrophobic material is selected from a group consisting of: silicon dioxide nanocoating, manganese oxide polystyrene, zinc oxide polystyrene, precipitated calcium carbonate, carbon nanotube structures, fluorinated silanes and fluoropolymer coatings. [6] System (100) according to claim 1, wherein the de-icing unit (106) comprises a heat pump (118) for recovering waste heat from a cooling system of a battery pack or a drive motor of the vehicle or both. [7] The system (100) according to claim 3, wherein the light intensity sensor (110) comprises: two or more transmitters (112-1, 112-2) arranged on an outer surface of the rear window, each of the two or more transmitters (112-1, 112-2) being positioned at an upper corner section of the rear window to emit light; and two or more receivers (114-1, 114-2) arranged on an interior surface of the rear window, each of the two or more receivers (114-1, 114-2) being positioned at a lower corner section to receive the light emitted through the rear window from the diagonally opposite transmitters (112-1, 112-2) of the two or more transmitters (112-1, 112-2); a control unit (104) being coupled to the two or more transmitters (112-1, 112-2) and the two or more receivers (114-1, 114-2) to determine the loss of light intensity as the light passes through the rear window. [8] System (100) according to claim 2, wherein the one or more dew point sensors (108) comprise a plurality of capacitive sensors, each of the plurality of capacitive sensors comprising a substrate base layer, a lower electrode, a middle layer and an upper electrode, wherein the middle layer is a hygroscopic metal oxide or polymer layer and the upper electrode is a water-permeable electrode. [9] System (100) according to claim 1, wherein the control unit (104) is configured to determine a heating time period for which the rear windscreen is supplied with heat on the basis of the determined fog index and controls the operation of the blower (116) accordingly. [10] Method (300) for defrosting a rear window of a vehicle, the method comprising the following steps: Detecting (302) the dew point of the air and the fog state of the rear window using one or more sensor units (102); Receiving (304) the detected dew point and fog state of the rear windshield at a control unit (104); Determining (306) a fog index on the control unit (104) based on the collected dew point and the fog state of the rear windshield, wherein the fog index indicates the extent of impaired visibility through the rear windshield; and Controls (308) based on the fog index, the speed of a blower (116) of a defrosting unit (106) configured to direct an airflow to the rear window in order to defog the rear window; wherein the defrosting unit (106) is configured to recover waste heat from a cooling system of a battery pack or a drive motor of the vehicle or from both.

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