Abstract:
A vehicular windshield wiping apparatus has a temperature sensor for sensing temperatures outside of the vehicle, a humidity sensor for sensing humidity outside of the vehicle, windshield wipers moved by a motor, an HVAC control module, and a wiper control module. The wiper control module activates the windshield wipers when the moisture level is at or above a threshold value and the temperature sensor senses a temperature at or below a threshold value. The wiper motor has a first wiper park position and a second wiper park position. The first wiper park position is approximately horizontal and the second wiper park position is at an angle to the first wiper park position, in a heated windshield zone. The second wiper park position allows the wipers to remain free of ice and snow when the outside temperature and moisture levels are beyond specific thresholds or a wiper stalk switch is activated.

Description:
FIELD 
   The present disclosure relates to a vehicular windshield wiper de-icing apparatus and method, and more specifically, to a windshield wiper de-icing apparatus and method based in part upon a wiper blade second park position, a heating, ventilating and air-conditioning (HVAC) system, a windshield wiper de-ice switch and associated controllers. 
   BACKGROUND 
   The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. Modern automotive vehicles typically have a pair of windshield wiper blades that retract to a substantially horizontal, stowed or park position when the wiper motor is turned off. During periods of freezing temperatures, the wiper blades are normally retracted to a position on or below the windshield such that the wiper blades do not benefit from heat emitting from an interior defroster outlet when heat is directed through the defroster outlet inside the vehicle cabin. The low wiper blade park position normally results in frozen wiper blades regardless of whether the blades are operating in an intermittent mode, as an example, or if they are turned off. When the wiper blades are operating in freezing temperatures, the frozen blades, normally made of rubber, accumulate ice and snow and do not properly seat against the windshield, thereby causing windshield streaks of water and ice. Additionally, contact noise results with the windshield due to the frozen, hardened wiper blades. Finally, when the wiper blades are turned on and operating, the wiper blades do not reside in a single position long enough to absorb heat emitting from the defroster vent, thereby resulting in frozen wiper blades. 
   Accordingly, a need exists for a windshield wiping apparatus and method of operation that efficiently and effectively heats wiper blades so that the blades remain pliable, do not accumulate ice and snow and seat properly against the windshield when off or in use in freezing temperatures. 
   SUMMARY 
   An apparatus and method for efficiently and effectively heating windshield wiper blades so that the blades remain pliable and seat properly against the windshield when in use in freezing temperatures is disclosed. Such an apparatus and method of operation prevents windshield streaks caused by ice and snow on the wiper blades, prevents ice and snow from accumulating on the blades, and prevents contact noise of the frozen wiper blades against the windshield. Such a windshield wiping apparatus may entail a wiper motor, wiper blades attached to wiper arms and together driven by the wiper motor to position the wiper blades in a first park position, and a wiper position switch having a first switch position and a second switch position. The second switch position corresponds to a second park position of the wiper blades, different from the first park position of the wiper blades, which corresponds to a first switch position. 
   Alternatively or additionally, a windshield wiping apparatus for a vehicle may utilize components for use in an automatic wiper de-icing mode. The components utilized may be a temperature sensor for sensing temperatures outside of the vehicle, a humidity sensor for sensing a moisture level outside of the vehicle, windshield wipers, an HVAC control module for directing air toward a designated windshield area, and a wiper control module for activating the windshield wipers when a humidity level is at or below a threshold value while the temperature sensor senses a temperature at or below a threshold value. A second wiper blade park position ensures that the wiper blades are heated and remain above freezing temperatures. 
   A method of controlling a wiper system may entail verifying that an outside temperature is less than or equal to a threshold temperature, verifying that a moisture level is greater than or equal to a threshold moisture level, actuating an HVAC mode motor so that air is directed to a specific windshield area of the vehicle, and actuating a wiper motor such that the windshield wipers are positioned in a specific, heated windshield area of the windshield. There may be two separate and distinct park positions of the windshield wipers on the windshield. A higher second park position on the windshield ensures that enough heat will penetrate the windshield and be absorbed by the wiper blades to prevent freezing of the wiper blades. 
   Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 

   
     DRAWINGS 
     The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
       FIG. 1  is a perspective view of an automobile depicting the location of wiper blades in a low, horizontal park position; 
       FIG. 2  is a front view of a vehicle depicting a windshield in which the wiper blades are parked at an angle P relative to the horizontal position of  FIG. 1 ; 
       FIG. 3  is an interior perspective view of a vehicular dash depicting HVAC controls, a defroster outlet, and a wiper stalk; 
       FIG. 4  is an enlarged view of a windshield wiper stalk depicting a de-ice button; 
       FIG. 5  is an enlarged view of the heating, ventilating and air-conditioning controls of  FIG. 3 ; 
       FIG. 6  is an exemplary view of a wiper motor depicting two motor shaft stop positions; 
       FIG. 7  is a diagram depicting the connection scheme of the various components of a wiper control system; and 
       FIG. 8  is a flowchart depicting operational flow of the wiper control system when in manual or automatic mode. 
   

   DETAILED DESCRIPTION 
   The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features. 
     FIG. 1  is a perspective view of a vehicle  10 , such as an automobile, depicting the location of a pair of wiper blades  14 ,  16  in a low park position  12 . Each individual wiper, a driver wiper  14  and a passenger wiper  16 , rests against a vehicle windshield  18 . Additionally, an outside moisture or humidity sensor  20  and an outside ambient temperature sensor  22  are depicted. While the humidity sensor  20  is depicted at a position adjacent the windshield  18 , its location is not restricted to such; likewise, while the temperature sensor  22  is depicted at the front of the vehicle  10 , it may be located elsewhere about the vehicle exterior.  FIG. 1  depicts the windshield wipers  14 ,  16  in a horizontal, first park position, below a heated windshield area  17  ( FIG. 2 ). The heated windshield area  17  is an interior area of the windshield where an interior windshield defroster outlet  20  ( FIG. 3 ) discharges warm air toward and against the vehicle windshield  18 . More specifically, the warm air is discharged against the interior surface of the windshield  18  at area  17 , which is above the low, horizontal park position  12  of the wiper blades  14 ,  16 . 
     FIG. 2  is a front view of a vehicle  10 .  FIG. 2  depicts, the wiper blades  14 ,  16  parked at an angle β relative to the horizontal wiper blades  14 ,  16  depicted in  FIG. 1 . When the wiper blades  14 ,  16  are parked at angle β, the position or state of the blades  14 ,  16  will be referred to as the heated park position  22  or angled park position. The heated park position  22  is opposed to the horizontal park position  12 , which is also referred to as the traditional or low park position. 
     FIG. 3  is an interior perspective view of a vehicular dash depicting a heating, ventilating and air-conditioning (“HVAC”) control panel  24 . An enlarged view of the control panel is depicted in  FIG. 5 . By adjusting the HVAC control panel  24 , a user may govern whether air is discharged from the windshield defroster outlet  20 , face outlet  26 , foot outlet  28 , or some combination thereof. More specifically, and with further reference to  FIG. 5 , the HVAC control panel  24  has a temperature adjustment  30 , a fan speed adjustment  32 , and an outlet selector  34 . More specifically, the temperature adjustment  30  may be a knob that may be rotated to increase or decrease the temperature of the water circulated to a heating system heater core of the HVAC system. Additionally, the fan speed adjustment  32  may be a knob that may be rotated to select a speed of the blower (fan). The fan speed governs the rate at which the heated air is blown from each of the windshield defroster outlet  20 , face outlet  26 , or foot outlet  28  if such vents are selected using the outlet selector  34 . The outlet selector  34  may be a knob that may be rotated to select windshield “W,” floor “FL,” face “FA,” or face/floor “FA/FL” as air discharge options. Although specific vents and combinations of vents are depicted, still other combinations are possible. 
   Further elaborating on the selectable outlets/vents from which heated air may be discharged, when the fan speed selector  32  is rotated to any of positions “1” through “5,” air will be blown by a fan such that the air will discharge from either the windshield defroster outlet  20 , face outlet  26 , or foot/floor outlet  28 , depending upon where the outlet selector  34  is positioned. Elaborating, the outlet selector  34  may be positioned at any of the windshield “W,” floor “FL,” face “FA,” or face/floor “FA/FL” positions. When the “W” position is selected, air will be discharged only from the windshield defroster outlet  20 . When the outlet selector  34  is positioned at the “FA” position, air is discharged only from the face vents  26 . There may be additional face vents in the dash of the vehicle, other than the three depicted in  FIG. 3 . When the “FL” position is selected, air will be discharged from the floor outlet  28 . Finally when the “FA/FL” position is selected, air will be discharged from both, the face vents  26  and the floor outlet  28 . Of course air will not be forcefully discharge from any vents unless the fan speed selector knob is positioned at one of positions “1” through “5.” The fan speed selector  32  may be rotated from a fan position of “0” corresponding to an off position, to a maximum blowing volume flow rate of “5.” 
   The temperature adjustment  30  may be rotated to adjust the temperature of air that is blown from an outlet  20 ,  26 ,  28 . The temperature adjustment  30  may be rotated from a cold or “C” position to an increasingly warmer position that concludes at hot or “H.”  FIG. 5  also depicts a fan speed selector position of “A,” which represents an “automatic” position setting, which will be described in detail, later. 
     FIG. 4  is an enlarged view of a windshield wiper stalk or arm that depicts a button known as a de-ice button  36 . The de-ice button  36  may be depressed to place the wiper control system into a manual wiper de-ice mode, which will be described in detail, later. 
     FIG. 6  depicts a wiper motor  56  having a shaft  58 . Depending upon the mode of the wiper motor  56 , the shaft  58  may stop in either a first stop position  60  or a second stop position  62 . The stop positions  60 ,  62  of the wiper motor govern the stop position of the wiper blades  14 ,  16  on the windshield  18 . When the de-ice button  36  is not depressed, the shaft  58  of the motor  56  will stop rotation of the motor at position  60 , which corresponds to the horizontal position of the wipers  14 ,  16 , as depicted in  FIG. 1 . When the de-ice button  36  is depressed, the shaft  58  of the motor  54  will stop rotation of the motor at position  62 , which corresponds to the heated park position  22 . 
     FIG. 7  depicts a wiper control system  39  that details a connection and communication scheme of the various wiper control system components. Generally, the wiper control system utilizes an HVAC control module  38  and a wiper control module  40 . The HVAC control module  38  communicates with the wiper control module  40  through a network line  42 . The HVAC control module  38  reads the ambient temperature sensor  48  such that the ambient temperature sensor inputs temperature information to the HVAC control module  38 . The HVAC control module  38  outputs control signals to the HVAC mode motor  50 , which controls the mode of an HVAC case  52 . That is, the HVAC mode motor  50  controls the position of air passage doors that govern where air is discharged inside a vehicle cabin. Although only shown in phantom, the HVAC case  52  contains the air switching doors that move in order to govern from which outlet(s) air is discharged into the vehicle cabin. Depending upon the configuration inside the HVAC case  52 , air may be directed from the defroster outlet  20 , the face outlet  26 , or the foot outlet  28 . Alternatively, air may be directed to a combination of the face outlet  26  and foot outlet  28 . 
   Continuing with  FIG. 7 , the wiper control module  40 , in addition to communicating with the network line  42 , receives input from the de-ice button  36 , also referred to as the stalk switch, and the humidity sensor  20 , also referred to as a moisture sensor. The wiper control module  40  then outputs information to the wiper blade motor  56 . While the wiper blade motor  56  is linked to the wiper blades  14 ,  16  to control positioning and movement of the wiper blades  14 ,  16  on the windshield  18 , details of the linkage connecting the wiper motor  56  and the wiper blades  14 ,  16  are not depicted in the Figures. Operations of the automatic windshield wiper de-ice system, and manual de-ice mode, will now be described. 
   To invoke the manual de-ice mode of the wiper blades  14 ,  16 , the de-ice button  36  on the stalk  35  must be depressed. Upon depressing the de-ice button  36 , the wiper blades  14 ,  16  will move from their normal, low-stowed, horizontal position, to their heated park position  22 . Manually depressing the de-ice button  36  causes the movement of the wiper blades,  14 ,  16  by the wiper blade motor  56  after receiving input by the wiper control module  40  ( FIG. 7 ). The user must then manually adjust the temperature adjustment  30 , fan speed adjustment  32 , and outlet selector  34 . The temperature adjustment  30  will have to be turned toward the “H” side of the dial, as depicted in  FIG. 5 , such that the blown air will permit the wiper blades  14 ,  16  to maintain at least 32 degrees Fahrenheit. Additionally, the fan speed selector  32  must be turned to one of “1” through “4,” and the outlet selector  34  must be turned to “W” so that warm air is directed to windshield area  17 . When warm air is directed against the inside surface of windshield area  17 , the windshield  18  will conduct heat through the windshield, which will then transfer into the parked blades  14 ,  16 . 
   In the event that the wiper blades  14 ,  16  are being utilized to wipe the windshield surface, the blades will not pass lower than an angular position, as depicted in  FIG. 2 . As such, the blades  14 ,  16  will momentarily stop and reverse direction at windshield area  17 . When the de-ice button is pressed, the wiper motor  56  will utilize the second stop position  62  of shaft  58 , which represents the position necessary to cause the blades to park in the heated park position  22  at angle β, relative to a lower, horizontal park position  12  that utilizes the first stop position  60  of shaft  58 . 
   Contrary to manual activation of the wiper de-ice system, utilization of the automatic windshield wiper de-ice system does not involve invocation of the de-ice button  36 . The automatic wiper de-ice system will now be explained.  FIG. 8  is a flowchart depicting an operational flow of a wiper control algorithm  70  that is utilized when the wiper control system  39  ( FIG. 7 ) is placed into automatic or “auto” mode by turning the fan speed selector  32  to “A” ( FIG. 5 ). From “start” at step  72 , the logic flow moves to step  74  at which a determination is made as to whether the de-ice button  36  on the stalk  35  is activated (depressed). If the de-ice switch  36  is activated, then the logic moves to step  80 , which activates the de-ice mode of the system. In such a situation, “activated” of step  74  means depressing a button  36 , or moving a linear switch on the stalk  35 , which may protrude from the steering column  37 . If the de-ice switch is activated, then the wiper blades  14 ,  16  will move from their low park position  12 , which is essentially horizontal and below the windshield area  17 , to the designated windshield area  17  of the windshield  18  ( FIG. 2 ). When in windshield area  17  of the windshield  18 , the wiper blades  14 ,  16  are in the heated park position  22 , also known as an angled park position. When in the heated park position  22 , as depicted in  FIG. 2 , the wiper blades  14 ,  16  will benefit from heat convection currents  21  and forced, blown heat that ultimately transfer through the windshield  18  and into the wiper blades  14 ,  16  to maintain the wiper blades  14 , 16  in a non-frozen state. 
   Regarding the transfer of heat, a blower  53  within the HVAC case  52  blows heat-laden air from the windshield defroster outlet  20  when the temperature adjustment  30  is adjusted toward the “H” side of the scale. The heat-laden forced air is directed at and contacts the interior of windshield  18  in windshield area  17 . Heat-laden air also may contact windshield area  17  by convection currents, which may run parallel to and within air currents  21 . The heat warms the interior portion of the windshield  18  at area  17 . The heat is then able to transfer through the windshield glass by conduction and subsequently warm the wiper blades  14 ,  16  by conduction because the wiper blades  14 ,  16  contact the windshield  18  at windshield area  17 . Because the heat contacting the wiper blades  14 ,  16  causes the wiper blades to rise above freezing temperatures, that is, rise above the freezing point temperature of 32 degrees F., or 0 degrees C., the wiper blades  14 ,  16  will not freeze. Furthermore, because wiper blades  14 ,  16  are normally made from a material that softens with the application of heat, such as rubber, the wiper blades will wipe more effectively because they will not become frozen, and thus not become hard, and will more effectively conform to the surface of the windshield  18 . The result of non-frozen wiper blades is that streaks from ice on the wiper blades  14 ,  16  will not occur. Pressing the button  36  is a manual activation of the wiper de-ice function. If the de-ice switch  36  is activated, then to deactivate the de-ice function, the de-ice switch  36  may be moved to the “OFF” position. 
   Continuing with the flow logic of  FIG. 8 , if the de-ice switch  36  on the stalk  35  is not activated, then the flow proceeds from step  74  to step  75 , where the system determines if the fan speed selector is on automatic or “A.” If the fan speed selector  32  is not turned to “A,” then because of the evaluations at step  74  and step  75 , neither the manual (de-ice button  36 ) or automatic (“A” of the fan speed selector  32 ) modes have been selected, respectively. As a result, the wiper blades  14 ,  16  stay in their horizontal position  12 . The logic flow proceeds to step  86 , which ends the routine; however, the logic flow then returns to step  72 , start. 
   If the fan speed selector  32  has been turned to “A” then the logic proceeds to step  76  where the ambient temperature, sensed by the ambient temperature sensor  22  ( FIG. 1 ) is read and compared to a value K_DE-ICE_TRHD 1 . K_DE-ICE_TRHD 1  is a threshold temperature that corresponds to a preset temperature, such as 28 degrees Fahrenheit, which is minus 2.2 (−2.2) degrees Celsius, which will be used as an example temperature. Assuming that K_DE-ICE_TRHD 1  is set at 28 degrees Fahrenheit, if the ambient temperature is greater than K_DE-ICE_TRHD 1 , then the logic flow moves to step  86 , which exits and ends the de-ice mode and returns the logic flow to step  72 , start. Alternatively, if the outside ambient temperature is less than or equal to K_DE-ICE_TRHD 1 , which for the present example is set at 28 degrees Fahrenheit, then the logic flow proceeds to step  78  where another evaluation is made. 
   Step  78  evaluates whether an outside humidity value is greater than a preset, predetermined humidity value, referred to as K_HUMIDITY_TRHD 1 ? If the outside humidity value is not greater than K_HUMIDITY_TRHD 1 , then the logic flows to step  86 , which causes the routine to exit and end the de-ice mode, and then directs the logic to step  72 , start. K_HUMIDITY_TRHD 1  is a relative humidity threshold such as 80%, as an example. Continuing with the logic flow, if the outside humidity value is greater than K_HUMIDITY_TRHD 1 , then the logic proceeds to step  80 , and the de-ice mode is activated. Again, the de-ice mode is activated because the fan speed adjustment  32  is on “A,” and the requisite outside temperature and humidity requirements have been met. The temperature sensor  22  reads the outside temperature, while the humidity sensor  20  reads the outside humidity. While the de-ice mode is activated, as described above, the logic continues to flow to step  82 , at which an evaluation is made. 
   Step  82  evaluates whether the outside ambient temperature is greater than K_DE-ICE_TRHD 2 . K_DE-ICE_TRHD 2  is a value that is utilized after the de-ice mode is activated. As an example, if K_DE-ICE_TRHD 1  is 28 degrees Fahrenheit, then K_DE-ICE_TRHD 2  must be greater than K_DE-ICE_TRHD 1 . K_DE-ICE_TRHD 2  may be 30 degrees Fahrenheit, or higher, for explanatory purposes of this flow logic. The outside ambient temperature must be above K_DE-ICE_TRHD 2  in order for the de-ice mode to exit and end at step  86  (turn off the de-ice function); such is the result when the step  82  evaluation is “Yes.” The logic flow ends and then immediately returns to step  72 , start. 
   If the result of the step  82  determination is “No,” then the logic proceeds to step  84 . At step  84 , an evaluation is made as to whether the outside humidity value is less than K_HUMIDITY_TRHD 2 . If the result of this evaluation is “No” then the logic returns to step  80  to cause the wiper system to remain in de-ice mode. If the result of this determination is “Yes,” then the logic flows to step  86 , which causes the logic to exit, end and then return to begin again at step  72 . 
   K_HUMIDITY_TRHD 2  is a value that is compared to the outside humidity value. As an example, if K_HUMIDITY_TRHD 1  is 80%, as used above, then K_HUMIDITY_TRHD 2  may be 70%. Therefore, when the outside humidity value is less than K_HUMIDITY_TRHD 2  (70% as an example), the flow logic will proceed to step  86  which exits and ends the routine, and then returns it to start  72 . However, if the outside humidity value is not less than K_HUMIDITY_TRHD 2  (70%), then the routine returns to step  80 , and the de-ice function continues with the wiper blades  14 ,  16  in the heated park position  22  ( FIG. 2 ). Generally, steps  82  and  84  govern whether the ambient conditions are such to warrant continuation or exit from the automatic de-ice function. Generally, if the ambient temperature is above freezing and/or the ambient humidity is below a specific value, then the automatic de-ice function will stop. However, even if the fan speed adjustment  32  is set to “A,” automatic, if ambient conditions are not within the prescribed parameters of K_DE-ICE_TRHD 2  and K_HUMIDITY_TRHD 2  according to the flow logic, then the de-ice mode will end and exit. 
   When in the heated park position  22  and when the fan speed selector is at the “A” position, the HVAC control module  38  automatically selects a fan speed. As an example, “2” or “3” may be selected, or the speed may vary with the outside ambient temperature. Likewise, the heated air temperature may automatically be adjusted by the HVAC control module  38  depending upon the temperature of the outside ambient air. The driver may control the speed at which the wiper arms move. In the event that the user desires a different fan speed, then the system can be turned off of the “A” setting and the stalk switch  36  can be manually switched to de-ice mode. This will permit the user to manually select any fan speed, and similarly, any forced air temperature. 
   The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.