Abstract:
A wiping system for use on a vehicle window comprises a window wiper assembly positioned proximate the window, a first sensor for detecting the presence of moisture on the window and a second sensor for detecting if the vehicle has been remotely started. A controller is coupled to the wiper assembly and to the first and second sensors and enables the wiper assembly when the vehicle has been remotely started and moisture is present on the window. The wiping system also comprises a third sensor for detecting the presence of moisture on the window, a fourth sensor for detecting vehicle shut-down, and a fifth sensor for sensing the temperature of the window. The controller is coupled to each of the third, fourth, and fifth sensors and enables the wiper assembly when the vehicle has been shut-down for less than a predetermined period of time, the temperature of the window exceeds a temperature threshold, and moisture is detected on the window.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates generally to a vehicular window wiper system, and more particularly to a vehicular window wiper system particularly suited for diminishing the formation of ice on a vehicle&#39;s windshield.  
       BACKGROUND OF THE INVENTION  
       [0002]     The formation of ice on vehicular windows is a well-known and problematic occurrence in cold environments. Ice may form on vehicle windows when snow contacts a heated window surface (e.g. heated from active defrosting elements or a heat source internal to the vehicle), melts, and freezes as the window surface cools (e.g. after all active defrosting elements and internal heat sources are no longer activated). Not only does the formation of ice obscure visibility, but it may also freeze automatic window wipers in place or simply decreases their effectiveness. Devices aiding in the removal of snow and ice are widely known and may take the form of, for example, conductive elements or heating strips that are embedded in a vehicle window. Devices of this type are commonly known as defrosters and work by increasing the temperature of the embedded conductive strips to heat the window thereby preventing the formation of ice and melting any ice already formed. Unfortunately, such defrosting systems may take an undesirably long period of time to melt enough ice to provide adequate visibility, especially if a large amount of ice is present and/or ambient temperature is low. Furthermore, it is impractical to operate a defrosting system when a vehicle&#39;s engine is not running due to vehicle battery limitations.  
         [0003]     Also well-known and the subject of numerous patents are vehicular window wiping systems. Such systems employ at least one wiping member typically having a blade which contacts a vehicle window. A motor drives the wiping member across a portion of the window&#39;s surface to physically remove any accumulated snow or rain thereby helping to maintain driver visibility. Such systems also help minimize the above described formation of ice by sweeping away snow before it melts. However, it is often impracticable to operate such wiper systems after ignition shut-down (e.g. as when a vehicle is parked) again due to the vehicle&#39;s battery limitations. Furthermore, wiping systems of the type described above are relatively ineffective for removing ice after it has formed and may, as previously mentioned, freeze in place.  
         [0004]     It is a common practice to use a manual cleaning tool to remove ice and snow. Such tools are well-known and may comprise a handle, a first end including an edged surface comprised of a hard material for scrapping ice off the window, and a second end comprising an edged surface of a soft material for removing moisture (i.e. a squeegee). Though such tools work reasonable well; their use requires time and energy. Also, such tools may not be able to substantially remove ice from wiper blades. Though this latter problem has been mitigated by providing wipers with integral heating elements or by providing vehicles with one or more fluid release nozzles positioned on a vehicle&#39;s hood or within a wiper blade assembly, such systems may be relatively complex and expensive to implement.  
         [0005]     It should thus be appreciated that it would be desirable to provide an improved system for minimizing the accumulation of ice and snow on vehicle windows that is relatively inexpensive to implement and simple to use.  
       BRIEF SUMMARY OF THE INVENTION  
       [0006]     According to an aspect of the invention there is provided a wiping system for use on a vehicle window comprising a window wiper assembly positioned proximate the window, a first sensor for detecting the presence of moisture on the window and a second sensor for detecting if the vehicle has been remotely started. A controller is coupled to the wiper assembly and to the first and second sensors and enables the wiper assembly when the vehicle has been remotely started and moisture is present on the window. The wiping system also comprises a third sensor for detecting the presence of moisture on the window, a fourth sensor for detecting vehicle shut-down, and a fifth sensor for sensing the temperature of the window. The controller is coupled to each of the third, fourth, and fifth sensors and enables the wiper assembly when the vehicle has been shut-down for less than a predetermined period of time, the temperature of the window exceeds a temperature threshold, and moisture is detected on the window. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]     The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and  
         [0008]      FIG. 1  is a block diagram of a vehicular window wiping system in accordance with the present invention; and  
         [0009]      FIG. 2  is a flow chart of an operational process suitable for use in conjunction with the wiping system shown in  FIG. 1 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0010]     The following detailed description of the invention is merely exemplary in nature and is not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the following description provides a convenient illustration for implementing exemplary embodiments of the invention. Various changes to the described embodiments may be made in the function and arrangement of the elements described herein without departing from the scope of the invention.  
         [0011]      FIG. 1  is a block diagram of a vehicular window wiping system  10  in accordance with the present invention. Wiping system  10  includes a processor or controller  22  for controlling a wiping apparatus comprising at least a motor  26  and a wiping member  28 . As can be seen, processor  22  is provided with a first output coupled to an input of wiper motor  26  to enable the transmission of wipe signals or commands thereto, and a second output coupled to a memory  20  for the transmission of data thereto. Processor  22  is also provided with a plurality of inputs each coupled to outputs of separate data sources. These data sources comprise user input interface  24 , memory  20 , a moisture sensor  12 , an ignition sensor  14 , a remote start sensor  16 , a window temperature sensor  18  and an ambient temperature sensor  29 . Moisture sensor  12  detects the presence of moisture (e.g. water droplets) on the exterior of a vehicle window, and ignition sensor  14  the starting and stopping of a vehicle&#39;s engine. Remote start sensor  16  detects the reception of a remote start signal emitted, for example, by a wireless keyfob  30 , and window temperature sensor  18  monitors the temperature of a vehicle&#39;s window. Ambient temperature sensor  29  monitors the outside air temperature. As is more fully explained below, processor  22  utilizes data provided by sensors  12 ,  14 ,  16 ,  18 , and  29  to determine whether or not a wipe command should be transmitted to motor  26  that, in turn, drives wiper member  28 .  
         [0012]     Sensors capable of detecting moisture present on a window&#39;s surface (e.g. moisture sensor  12 ) are well-known in the art. One known type of moisture sensor employs a plurality of adjacent pairs of conductive strips coupled to a current detector and embedded on a window&#39;s surface. A processor monitors the current detector to determine the number of pairs of conductive strips contacted by moisture droplets and calculates therefrom the relative wetness of the window&#39;s surface. Another known moisture sensor, commonly referred to as optoelectronic rain sensor, employs optical sensors to determine light conditions from which the degree of surface wetness may be calculated. It should be appreciated that moisture sensor  12  may take either of these forms or any other form suitable for detecting the presence of moisture on a window&#39;s outer surface.  
         [0013]     Memory  20  stores a set of predetermined conditions that determine the processing path taken by processor  22  and, ultimately, whether or not processor  22  delivers a wipe command to wiper motor  26 . For example, memory  20  may store predetermined time and temperature thresholds. The time threshold represents a finite period of time during which processor  22  may activate wiper motor  26  after ignition sensor  14  senses that the vehicle is no longer running. If, for example, the time threshold is five minutes, wiping would continue for a five minute period following ignition shut-down if other conditions described below are satisfied.  
         [0014]     In addition to a time threshold, memory  20  may store a temperature threshold that represents a temperature below which wiper motor  26  will not be enabled after ignition shutdown. Specifically, if window temperature sensor  18  indicates that the window temperature is less than or equal to the temperature threshold, processor  22  will not activate wiper motor  26 . It is preferable that the temperature threshold be approximately equivalent to the freezing temperature of water. In this manner, wiping control system  10  may reduce the formation of ice by instructing wiper motor  26  and therefore wiper member  28  to sweep away snow when the window&#39;s surface is warm enough to melt snow, while conserving energy by not commanding wipes when the window&#39;s surface is too cold to melt snow. Wiping control system  10  is thus configured to substantially wipe away snow and water before it freezes on the vehicle&#39;s window.  
         [0015]     In addition, memory  20  may store an ambient temperature threshold that represents a temperature above which wiper motor  26  will not be enabled after ignition shutdown or remote start activation. Specifically, if the air temperature sensor  29  indicates that the air temperature is greater than or equal to the ambient temperature threshold, processor  22  will not activate wiper motor  26 . It is preferable that the temperature threshold be approximately equivalent to or somewhat greater than the freezing temperature of water (e.g. 45° F.). In this manner, wiping control system  10  need not operate when there is little chance of ice formation.  
         [0016]     User input  24  may take any form suitable for enabling an operator to provide desired selection data. For example, user input  24  may simply comprise a single input (e.g. a button or switch) for activating the inventive wiping system. Alternatively, user input  24  may comprise an additional input for receiving operator selection data regarding wiper speed or auxiliary functions (e.g. audible or visual impending wipe alerts). If desired, user input  24  may also be utilized by an occupant of the vehicle to select preferred time and/or temperature thresholds. In this case, processor  22  would cause the changed time and/or temperature threshold to be stored in memory  20 .  
         [0017]      FIG. 2  is a flow chart of the process carried out by inventive window wiping system  10  shown in  FIG. 1 . The process begins at START  32 . Steps  34 ,  44 , and  46  are dependent upon user-selection data received from user input  24  ( FIG. 1 ), and steps  36 ,  38 , and  42  are dependent upon data received from remote start sensor  16  ( FIG. 1 ), ignition sensor  14  ( FIG. 1 ), and moisture sensor  12  ( FIG. 1 ) respectively. Steps  37  and  40  are dependent upon data received from window temperature sensor  18  ( FIG. 1 ), and step  33  is dependent upon data received from ambient temperature sensor  29  ( FIG. 1 ). Steps  38  and  40  are further respectively dependent on the time threshold (represented by the letter X) and the temperature threshold (represented by the letter Y) described hereinabove. Steps  33  and  37  are further respectively dependent on the temperature thresholds represented by the letters Q and Z.  
         [0018]     The inventive wiping method may begin with a determination that the ambient temperature is below threshold Q as is shown at  33  and a determination that the wiping feature has been enabled as is shown at  34 . The user may enable the system by means of user input  24  ( FIG. 1 ) which may comprise a dedicated switch, a menu system, or other mechanism within a multifunctional display and control device. Alternatively, the vehicle may be configured such that the wiping feature is always enabled.  
         [0019]     If the wiping feature is disabled, the wiping system remains dormant. If, however, the wiping feature has been enabled, processor  22  monitors the output of remote start sensor  16  to determine if the vehicle has been started (e.g. remotely by means of wireless keyfob  30 ) as is shown at  36 . If the vehicle has been started, processor  22  interrogates moisture sensor  12  ( FIG. 1 ) to determine if moisture is present on the window as is shown at  42 . The absence of moisture on the window will result in the wiping function remaining dormant. If, however, moisture is detected on the window, and if the window temperature is above a temperature threshold Z as is shown at  37 , a wiping phase (i.e. comprising processing steps  44 ,  46 , and  48 ) will begin as will be more fully described below.  
         [0020]     The wiping phase may be entered by means of a second path in  FIG. 2 . That is, if a vehicle start is not detected at  36 , processor  22  monitors ignition sensor  14  and an internal timer to determine if the ignition has been turned off for more than a predetermined period of time X (stored in memory  20 — FIG. 1 ) as is shown at  38 . If the time period (e.g. five minutes) has elapsed, the wiping function remains dormant. In this manner, the system may prevent accumulation of snow during short parking periods without remaining continuously active. Since an objective is to prevent the freezing of precipitation and melted snow on the vehicle&#39;s window, the time period (X) should preferably be greater than the time it takes for the window to reach a freezing temperature.  
         [0021]     If the elapsed time (t) is less than or equal to elapsed time threshold X, processor  22  monitors temperature sensor  18  ( FIG. 1 ) to determine if the window&#39;s temperature is greater than a temperature threshold Y (e.g. freezing) stored in memory  20  as is shown at  40 . If the temperature of the window is below freezing, it is assumed that accumulated snow will not melt and later freeze. Thus, in this particular case, wiping is not necessary. If, however, the window&#39;s temperature (t) is greater than the threshold (i.e. t&gt;Y), processor  22  searches for moisture on the window as previously described.  
         [0022]     To summarize, the wiping phase corresponding to steps  44 ,  46 , and  48  may be reached by two path&amp; The first occurs when the system is enabled, the vehicle is started, the ambient temperature is below a threshold, moisture is present on the window, and the window is above a temperature (i.e. steps  33 ,  34 ,  36 ,  37 , and  42 ). The second occurs within a predetermined period of time after an ignition cycle if the temperature of the window exceeds a threshold (e.g. freezing), the ambient temperature is below a threshold (e.g. freezing) and moisture is present on the window (i.e. steps  33 ,  34 ,  36 ,  38 ,  40 , and  42 ).  
         [0023]     Prior to the wiping phase, user selection data is provided via user input  24  ( FIG. 1 ). Specifically, a user may select a desired wiping speed and activate various auxiliary features (e.g. visual, audible, and/or tactile alerts) (steps  44  and  46 ). This user selection data is stored in memory  20  and recalled during the wiping phase (i.e. processing steps  44  and  46 ). Thus, during such a wiping phase, processor  22  interrogates memory  20  regarding the user-selected wiping speed and user-actuated auxiliary features and signals wiper motor  26  accordingly. Actual wiping commences (i.e. step  48 ) as wiper motor  26  receives a wipe command from processor  22  and drives wiper  28  across the vehicle window.  
         [0024]     It should thus be appreciated that an improved system for minimizing the formation of ice and snow on vehicle windows has been provided that is relatively inexpensive to implement and simple to use.  
         [0025]     While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing the exemplary embodiment or exemplary embodiments. It should be understood that various changes can be made in the function and arrangement of elements without departing from the scope of the invention as set forth in the appended claims and the legal equivalents thereof