Abstract:
A washer fluid system provides washer fluid by blending concentrated washer fluid with waste water produced in the operation of a fuel cell. The concentrated washer fluid is stored in a replenishable container. A mixing pump automatically meters the appropriate ratio of concentrated washer fluid to water (i.e., 1:10), preferably by a dual chamber arrangement, wherein the waste water from the fuel cell and the concentrated washer fluid are drawn from their respective sources and mixed, creating a mixed washer fluid having the proper ratio of water to washer fluid concentrate. In a first embodiment, the system creates the mixed washer fluid in real-time on demand of the wiper system; in a second embodiment a storage reservoir holds mixed washer fluid for stand-by use of the wiper system.

Description:
TECHNICAL FIELD 
     The present invention relates to exterior glass surface washer fluid systems of motor vehicles, and more particularly to a washer fluid system of fuel cell-powered vehicles that blends the waste water produced by the fuel cell thereof with a washer fluid concentrate. 
     BACKGROUND OF THE INVENTION 
     A fuel cell is an electrochemical energy conversion device that converts energy from the chemical reaction of a fuel and an oxidant into electrical energy. Proton exchange membrane (PEM) fuel cells are the most commonly used for vehicular power plants. In these fuel cells, hydrogen rich gas (H 2 ) is supplied as fuel and oxygen gas (O 2 ) or air is supplied as the oxidant. In the subsequent oxidation-reduction reactions, the H 2  is oxidized and reacts with O 2  to form water and produce electricity for the operation of an electrical power plant of the vehicle. The stoichiometry of the chemical reactions is such that the amount of water produced is proportional to the power consumed by the vehicle. The operational characteristics of the PEM fuel cell require particular levels of humidity to be efficient. However, in any PEM fuel cell which produces the requisite power to operate a motor vehicle, water is produced far in excess of the amount required to maintain the proper humidity in the fuel cell. Much effort in the design of these cells has been spent in managing the waste water issue. 
     Due to the economics of motor vehicle energy consumption, much of the design process of motor vehicles has been dictated by reducing vehicle weight and the space of non-passenger areas. This lowers the energy consumption directly by the lowering of weight and indirectly by allowing for more flexibility in the design of aerodynamically important surfaces through minimizing volume requirements imposed on designs. This is particularly important in electrically powered vehicles in which it is more difficult to provide marginal increases in power. Any design changes which allow for reduction in weight or space of electrically powered vehicles would have greater impact on the operational cost when compared to similar changes in gasoline powered vehicles. 
     Washer fluid systems are necessary for the safe operation of motor vehicles yet place a burden on both weight and space in the present configuration of motor vehicles. The washer fluid mix presently employed in motor vehicles consists primarily of water with antifreeze and cleaning components such as alcohols, amines, and non-ionic detergents. Typically, this mix is stored in premium compartment space to facilitate the operator&#39;s ability to refill the storage containers when needed. This results in designs which place large heavy containers, which are primarily filled with water, in premium areas of vehicle space. A design strategy which would call for the storage of only the concentrate form of the washer fluid would radically reduce the space and weight required by the washer fluid system. 
     What remains needed in the art is to somehow utilize the waste water, produced in the operation of the fuel cell, to provide washer fluid. 
     SUMMARY OF THE INVENTION 
     The present invention is a washer fluid system for fuel cell vehicles which provides washer fluid by blending concentrated washer fluid with waste water produced in the operation of a fuel cell. The concentrated washer fluid may be stored in a container which may be placed at any location, including, for example, a non-premium location such as for example a frame rail, engine cradle rail, behind wheel-well housings, etc. 
     A first preferred embodiment of the present invention includes an electronic control module (ECM), a mixing pump and a concentrated washer fluid reservoir. The ECM integrates inputs through the vehicle wiper system and produces an output in the form of signals to the mixing pump. The mixing pump serves as the mechanical actuator of the washer fluid system, and automatically meters the appropriate ratio of concentrated washer fluid to water (i.e., 1:10), preferably by a dual chamber arrangement. The waste water from the fuel cell and the concentrated washer fluid are drawn from their respective sources and mixed, creating a mixed washer fluid having the proper ratio of water to washer fluid concentrate. Through these two principal components the operations of the present invention are initiated and controlled. 
     These components of the washer fluid system further include two primary interfaces. One interface is with the vehicle driver, consisting of an operational input through the wiper system to indicate a demand for mixed washer fluid. Additionally, the driver may be notified through an indicator when the concentrated washer fluid level is low, as well as providing a means for the driver to replenish the concentrated washer fluid reservoir. Additionally, the washer fluid system must interface with the fuel cell system to provide the required waste water. This would, for example, involve a valve or splitter which would serve as an actuator to divert the flow of the waste water from the normal disposal pathway designed into the fuel cell system to the washer fluid system. 
     In a second embodiment of the present invention, in addition to the above described components, a storage reservoir of mixed washer fluid is further included which is connected to the wiper system, wherein the mixed washer fluid is produced by the aforementioned mixing process, and wherein the ECM receives additional input from sensors detecting the fluid level in the storage reservoir. 
     Accordingly, it is an object of the present invention to provide a washer fluid system that collects waste water from a fuel cell and blends it with washer fluid concentrate to form mixed washer fluid on an as needed basis and/or to provide washer fluid for a storage reservoir. 
     This and additional objects, features and advantages of the present invention will become clearer from the following specification. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of a first preferred embodiment of the present invention. 
         FIG. 1A  is a schematic view of a first preferred embodiment of a mixing pump of the present invention. 
         FIG. 1B  is a schematic view of a second preferred embodiment of a mixing pump of the present invention. 
         FIG. 2  is a schematic representation of a structural implementation of the controls for the first preferred embodiment of the present invention. 
         FIG. 3  is a flow diagram of the logic for the principle algorithm of the electronic control module for the first preferred embodiment of the present invention. 
         FIG. 4  is a flow diagram of the logic of the level control algorithm of the electronic control module for monitoring the level of the concentrated fluid level according to the present invention. 
         FIG. 5  is a schematic diagram of a second preferred embodiment of the present invention which contains a reservoir for mixed washer fluid. 
         FIG. 6  is a schematic representation of a structural implementation of the controls for the second preferred embodiment of the present invention. 
         FIG. 7  is a flow diagram for the logic for the principle algorithm of the electronic control module for the second preferred embodiment of the present invention 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the Drawing,  FIGS. 1 ,  2  and  3  depict a first preferred embodiment and  FIGS. 5 through 7  depict a second preferred embodiment, wherein  FIGS. 1A ,  1 B and  4  are shared therebetween, of a washer fluid system for fuel cell vehicles according to the present invention. 
     Referring firstly to  FIGS. 1 through 2 , the components of the first preferred embodiment of the washer fluid system  100  are depicted, wherein in  FIG. 1  heavy lines with arrows demarcate fluid conduits and lighter lines demarcate intercommunication. 
     In a fuel cell-powered vehicle, a fuel cell  102  produces excess water in the course of its operation. According to the present invention, this excess water will pass through a diverter valve  104  which has two settings. The diverter valve  104  is interconnected with a diverter valve actuator  106 . Under normal operating conditions, the diverter valve  104  is set to divert the water to a conventional modality of water disposal  108  as ordinarily designed into the fuel cell vehicle. 
     An electronic control module (ECM)  110 , well known in the art, is in communication with, and activates components of, the washer fluid system  100  in order to control the operation thereof. 
     A concentrated washer fluid reservoir (or tank)  120  holds concentrated washer fluid. The concentrated washer fluid reservoir  120  may be placed in any convenient location, including a non-premium location of the vehicle, as for example a frame rail, engine cradle rail, behind a wheel well housing, etc. The concentrated washer fluid reservoir  120  is preferably equipped with a bi-level sensor  122  capable of detecting fluid levels below or above two separate levels, wherein such a bi-level sensor is well known in the art. A level indicator  126 , as for example a lamp located in the instrument area of the vehicle, is in communication with the ECM  110  and is lit when the concentrated washer fluid reservoir  120  needs refilling. 
     A mixing pump  112  pumps two liquids (the water from the fuel cell  102  and the concentrated washer fluid from the concentrated washer fluid reservoir  120 ) and mixes them in a predetermined proportion, such as for example a 10 to 1 ratio of water to concentrated washer fluid. By way of preferred exemplification, a larger chamber  114 A and a smaller chamber  114 B are utilized, which are mutually scaled by relative volume to the precise ratio required for the mixing of water with concentrated washer fluid to thereby provide a mixed washer fluid for use by the wiper system  124 . 
     A first example of the mixing pump ( 112  in FIG.  1  and  112 ′ in  FIG. 4 ) is depicted at  FIG. 1A . A motor  150  has a 10 to 1 gear drive linkage  152  to the respective impellers  154 ,  156  of a larger chamber  158  and a smaller chamber  160 . The larger chamber has an inlet  162  into which water  164  from the fuel cell enters, and an outlet  166 . The smaller chamber has an inlet  168  into which concentrated washer fluid  170  of the concentrated washer fluid reservoir enters, and an outlet  172 . A mixing line  174  is connected to both outlets  166 ,  172  and provides a common line of mixed washer fluid  176  for use by the wiper system. 
     A second example of the mixing pump ( 112  in FIG.  1  and  112 ′ in  FIG. 4 ) is depicted at  FIG. 1B . A motor  150 ′ has a 10 to 1 gear drive linkage  152 ′ to the respective impellers  154 ′,  156 ′ of equally sized first and second chambers  158 ′,  160 ′ such that the first chamber will pump liquid ten times the volume per unit time as that pumped by the second chamber. The first chamber has an inlet  162 ′ into which water  164  from the fuel cell enters, and an outlet  166 ′. The second chamber has an inlet  168 ′ into which concentrated washer fluid  170  of the concentrated washer fluid reservoir enters, and an outlet  172 ′. A mixing line  174 ′ is connected to both outlets  164 ′,  168 ′ and provides a common line of mixed washer fluid  176  for use by the wiper system. 
     It will be understood that the mixing pump ( 112  in FIG.  1  and  112 ′ in  FIG. 4 ) may have other configurations whereby a fixed predetermined ratio of water from the fuel cell to concentrated washer fluid from the washer fluid reservoir is provided, as for example via metering orifices, electronic regulation of relative fluid flow rates from two separate pumps, etc. 
     A moisture sensor  116  is preferably contained within the larger chamber  114 A and is in communication with the ECM  110 . The purpose of the moisture sensor is to detect the presence of water in the larger chamber  114 A, whereby it can be removed (discussed below) before freezing in cold weather (the smaller chamber has concentrated washer fluid therein which will is not subject to freezing). The moisture sensor  116  and operational aspects related thereto (discussed below) are obviated if the mixing pump  112  and its associated water inlet line are kept above freezing. 
     The wiper system  124  is conventional and well known in the art, consisting of at least one wiper and motor combination for wiping the external glass surfaces of the vehicle, a control interface so that the driver  118  may control its operation, and a means for pumping and spraying washer fluid onto the wiped glass. 
     Referring primarily now to  FIG. 2 , which is a schematic representation of a structural implementation of the controls, the driver  118  commands spray of mixed washer fluid by wiper system  124 , whereupon the wiper system sends a signal to the ECM  110  that there is a demand for mixed washer fluid. The moisture sensor  116  sends signal to the ECM  110  indicating the presence, or lack of presence, of moisture in the larger chamber  114 A of the mixing pump  112 . The bi-level sensor  122  located in the concentrated washer fluid reservoir  120 , provides information to the ECM  110  indicating the level of concentrated washer fluid in the concentrated washer fluid reservoir  120 . The ECM  110  processes these inputs and, by means of operational algorithms (discussed below with respect to  FIGS. 3 and 4 ), selectively outputs operational signals. In this regard, the ECM  110  has three channels of output data, namely: a signal to the diverter valve actuator  106 , a signal to the mixing pump  112  and a signal to the level indicator lamp  126 . 
     Referring next to  FIG. 3 , a principal algorithm  200  for programming the ECM  110  is shown. The program is initialized at Block  202 . The program advances to Block  204 , where it remains until a demand signal is received from the driver  118  via the wiper system  124 , indicating there is a demand for mixed washer fluid. Upon receipt of the demand signal, the program advances to Block  206 . At Block  206  the ECM  110  issues a signal to the diverter valve actuator  106 , which thereupon sets the diverter valve  104  to divert water to the larger chamber  114 A of the mixing pump  112 . The program then advances to Block  208  whereat the mixing pump  112  is activated. The program now advances to decision Block  210  where inquiry is made whether the driver  118  is still demanding washer fluid through the wiper system  124 . If the answer to the inquiry is yes, then the program advances to Block  212 . At Block  212  a predetermined waiting period occurs before the program returns to Block  210 ; for example, this wait may be about two seconds and allows for a minimum time of spray. However, if the answer to the inquiry of Block  210  is no, then the program advances to Block  214 . At Block  214  a signal is sent by the ECM  110  to the diverter valve actuator  106  to close the diverter valve  104 . The program then advances to decision Block  216 , where inquiry is made whether the moisture sensor  116  indicates the larger chamber  114 A of the mixing pump  112  is still wet. If the answer to the inquiry is yes, then the pump remains running to pull air through the larger mixing chamber  114 A of the mixing pump  112  in order to dry the larger chamber  114 A and its related tubing. If the answer to the inquiry of Block  216  is no, then the larger chamber  114 A is sufficiently dry, and the program advances to Block  218 . At Block  218  the ECM  110  sends a signal to turn off the mixing pump  112  and the program returns to Block  204  to await a next demand signal from the wiper system  124 . 
     Referring to  FIG. 4 , the algorithm for controlling the level of concentrated washer fluid  300  in the concentrated washer fluid reservoir  120  is depicted. 
     The program is initialized at Block  302 . The program proceeds to decision Block  304 , where inquiry is made whether the concentrated washer fluid level is below a first predetermined level. If the answer to the inquiry is no, then the program proceeds to Block  306  and waits for a predetermined duration, as for example one minute so that the lamp won&#39;t be subject to rapid toggling on and off when the fluid level is at the sensor level, before returning to Block  304 . If the answer to the inquiry of Block  304  is yes, then the program advances to Block  308 , whereat the indicator lamp  126  is lit, indicating to the driver there is a need to replenish concentrated washer fluid in the concentrated washer fluid reservoir  120 . The program then proceeds to decision Block  310  where inquiry is made whether the concentrated washer fluid is above a second predetermined level, wherein the second predetermined level is higher than the first predetermined level. If the answer to the inquiry is no, then the program proceeds to Block  312  and waits for a predetermined interval before returning to Block  310 , again for the purpose of preventing lamp toggling. If the answer to the inquiry of Block  310  is yes, then the program proceeds to Block  314 . At Block  314  the indicator lamp  126  is turned off and the program returns to Block  304 . 
     Referring now to  FIGS. 5 and 6 , depicted is a second preferred embodiment of the washer fluid system  100 ′ according to the present invention, which now utilizes a storage reservoir (or tank)  128  for mixed washer fluid, wherein like parts to those described with respect to  FIGS. 1 and 2  have like numbers with a prime, wherein the detailed description thereof need only be minimal in view of the detailed description hereinabove with respect to the first preferred embodiment, and wherein in  FIG. 5 , as in  FIG. 1 , heavy lines with arrows demarcate fluid conduits and lighter lines demarcate intercommunication. 
       FIG. 5  depicts a fuel cell-powered vehicle fuel cell  102 ′ that produces excess water in the course of its operation, wherein this excess water passes through a diverter valve  104 ′ which has two settings and is interconnected with a diverter valve actuator  106 ′. Under normal operating conditions, the diverter valve  104 ′ is set to divert the water to a conventional modality of water disposal  108 ′ as ordinarily designed into the fuel cell vehicle. An electronic control module (ECM)  110 ′ is in communication with and activates components of the present invention in order to control the operation therein. A concentrated washer fluid reservoir  120 ′ provides concentrated washer fluid, and may be placed in any convenient location as described above. The concentrated washer fluid reservoir  120 ′ is preferably equipped with a bi-level sensor  122 ′ capable of detecting fluid levels below or above two separate levels, as described above. A mixing pump  112 ′ pumps two liquids (the water from the fuel cell  102 ′ and the concentrated washer fluid from the concentrated washer fluid reservoir  120 ′) and mixes them in a predetermined proportion, such as for example a 10 to 1 ratio of water to concentrated washer fluid. By way of preferred exemplification, a larger chamber  114 A′ and a smaller chamber  114 B′ are utilized which are mutually scaled by relative volume to the precise ratio required for the mixing of water with concentrated washer fluid to thereby provide a mixed washer fluid for use by the wiper system  124 . The mixing pump  112 ′ may be as described with respect to  FIGS. 1A and 1B , or be otherwise configured, as mentioned above to provide a proper ratio of mixed liquids output. A moisture sensor  116 ′ is optionally contained within the larger chamber  114 A′ and is in communication with the ECM  110 ′. The wiper system  124 ′ is conventional, as described above. A level indicator  126 ′, as for example a lamp, is located in the instrument area of the vehicle, wherein the lamp is in communication with the ECM  110 ′ and is lit when the concentrated fluid reservoir  120 ′ needs refilling. 
     The storage reservoir  128  is connected to the output of the mixing pump  112 ′. The storage reservoir  128  may be located at any convenient location, inside or outside of the engine compartment, and holds mixed washer fluid exiting the mixing pump  112 ′, formed as described above, wherein the mixed washer fluid in the storage container is delivered to the wiper system  124 ′ upon demand of the driver  118 ′. The storage reservoir  128  preferably contains a bi-level mixed washer fluid level sensor  130 , which, as mentioned, is known in the art, and which is in communication with the ECM  110 ′. 
     Referring now particularly to  FIG. 6 , which is a schematic representation of a structural implementation of the controls, the mixed fluid level sensor  130 ′ sends a signal to the ECM  110 ′ upon the fluid level dropping below a predetermined threshold indicating a demand for mixed washer fluid. The moisture sensor  116 ′ sends signal to the ECM  110 ′ indicating the presence, or lack of presence, of moisture in the larger chamber  114 A′ of the mixing pump  112 ′. The bi-level sensor  122 ′ located in the storage reservoir  120 ′ provides a signal to the ECM  110 ′ indicating the level of concentrated washer fluid therein. The ECM  110 ′ processes these inputs and by means of operational algorithms (see  FIG. 7 ), and selectively outputs operational signals. The ECM  110 ′ has three channels of output data, namely a signal to the diverter valve controller  106 ′, a signal to the mixing pump  112 ′ and a signal to the level indicator lamp  126 . 
     In this scheme of the second preferred embodiment, the ECM  110 ′ has communication with the bi-level sensor  122 ′ in the storage reservoir  120 , and there is no need ECM communication with the wiper system  124 ′ (as in  FIG. 2 ), in that the wiper system draws mixed washer fluid from the mixed washer fluid reservoir, wherein no communication between the wiper system  124 ′. 
     Referring now to  FIG. 7 , the principal algorithm  400  for the ECM  110 ′ is shown. The program is initialized at Block  402 . The program advances to decision Block  404  where inquiry is made whether the washer fluid level in the mixed washer fluid reservoir  128 ′ has dropped below a predetermined level. If the answer to the inquiry is no, then the program proceeds to Block  406  where the program waits for a predetermined amount of time (as for example one minute to prevent lamp toggling as discussed hereinabove) before returning to Block  404 . If the answer to the inquiry of Block  404  is yes, the program proceeds to Block  408 . At Block  408 , the ECM  110 ′ issues a signal to the diverter valve actuator  106 ′, which thereupon sets the diverter valve  104 ′ to divert water to the larger chamber  114 A′ of the mixing pump  112 ′. The program then advances to Block  410  whereat the mixing pump  112 ′ is activated. The program now advances to decision Block  412  where inquiry is made whether the mixed washer fluid is above a predetermined level. If the answer to the inquiry is no, then the program proceeds to Block  414  and waits for a predetermined interval (i.e., one minute) before returning to Block  412 . If the answer to the inquiry of Block  412  is yes, the program then advances to Block  416 . At Block  416  a signal is sent by the ECM  110 ′ to the diverter valve actuator  106 ′ which causes closure of the diverter valve  104 ′. The program then advances to decision Block  418 , where inquiry is made whether the moisture sensor  116 ′ indicates the larger chamber  114 A′ of the mixing pump  112 ′ is still wet. If the answer to the inquiry is yes, then the pump remains running to pull air through the larger mixing chamber  114 A′ of the mixing pump  112 ′ in order to dry the larger chamber  114 A′ and its related tubing. If the answer to the inquiry is yes, the program advances to Block  420 , whereat the program causes the ECM  110 ′ to send signal to turn off the mixing pump  112 ′ and the program returns to Block  404 . 
     It is to be understood that the program described at  FIG. 4  would be utilized to implement the bi-level concentrated washer fluid sensor  122 ′ of  FIG. 6 . 
     To those skilled in the art to which this invention appertains, the above described preferred embodiment may be subject to change or modification. Such change or modification can be carried out without departing from the scope of the invention, which is intended to be limited only by the scope of the appended claims.