Abstract:
A water management system for a motor vehicle in which water is collected from the condenser ( 1 ) of the air-conditioning unit, stored in a master water tank ( 5 ) and distributed therefrom to the battery ( 15 ), screen wash jet ( 27 ) and radiator ( 37 ). The vehicle owner is thus spared the inconvenience of regularly checking and topping up the water supply for these items. The risk of breakdown is also reduced. In another aspect of the invention, a wet battery ( 15 ) incorporates a plurality of float valves ( 75 ) for regulating the fluid level in respective cells ( 61, 63 ) of the battery. Water is passed through a common channel ( 23 ) into which the float valves ( 75 ) open when the fluid level is below a preset limit. The battery fluid is thereby automatically kept at the required level for optimum performance and lifetime of the battery.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a wet battery which needs to be topped up periodically with water or other fluid. The invention also relates to a vehicle-based water management system for use in connection with at least one unit on the vehicle which requires water for its operation. 
     2. Description of the Prior Art 
     In a motor vehicle such as a car, there are a number of units which require water for their operation and in which the supply of water must be regularly checked and topped up if necessary. These units include the radiator, the screen wash and the battery. Water is lost from the radiator due to leakage and evaporation. Water is consumed in normal use of the screen wash. Water is lost from the battery through evaporation and boiling caused by heating of the battery during its charging and discharging cycle and due to the engine temperature. In an electric vehicle, the batteries constitute the source of motive power, so it is particularly important that they be maintained in good condition at all times. 
     Presently, the vehicle owner must routinely inspect and refill the water supply in all these units. This is an inconvenient and irritating burden, yet damage may result or safety be compromised if the task is not done. Additionally, the water level in the cells of the or each battery should be carefully adjusted in order to optimize the performance and lifespan. This is particularly important in the case of an electric car or other vehicle. However, getting the water level right requires some skill and knowledge. Moreover, the need to check and fill each cell individually is time-consuming. 
     The present invention arose partly from a consideration of these problems and how they may be overcome. 
     SUMMARY OF THE INVENTION 
     In one aspect, the invention provides a wet battery comprising a plurality of cells, each cell having a respective fluid inlet, the battery having a channel which is shared by the fluid inlets for supplying fluid such as water to the cells of the battery, wherein each cell includes a float valve associated with its fluid inlet and arranged to automatically open for communication with the channel when the fluid in the cell is below a predetermined level. 
     According to this aspect of the invention, the procedure of maintaining the fluid level of each cell of the battery is simplified and may be automatically regulated, thereby ensuring optimum performance and lifespan. 
     In a preferred embodiment, the battery has an integral reservoir for temporarily holding a quantity of water. The reservoir is periodically filled manually or automatically, and then empties its content through the channel, which supplies the cells as required. Any excess water exits the channel through an overflow or may even be returned to the reservoir. According to this arrangement, the fluid level is automatically set by the valves and it is impossible to overfill the battery. 
     In another aspect, the invention provides a water management system on a vehicle, the system comprising water collecting means for providing a supply of water and distribution means for distributing the water from the supply to a plurality of units on the vehicle which require water for their operation. 
     According to this other aspect of the invention, a supply of water is always conveniently available for use by the units requiring water for their operation. The plurality of units may consist of a bank of two or more batteries in the case of an electric vehicle. 
     The water collecting means may be a master or central storage vessel which is filled manually. However, the water collecting means may include a source which generates water as a by-product. In one embodiment of the invention, an air-conditioning system is employed to provide the water supply. The condensate formed on the condenser of the air-conditioning system offers a reliable and clean source of water. It is also simple to collect, for example by using the conventional drip pipe of the condenser to feed the condensed water into a storage tank. 
     The inventor has tested the system on his own car and found that one-half of a liter of water may be collected from the car&#39;s air-conditioner in one 30-minute city journey. This result indicates that more than a sufficient amount of water to meet the usual requirements of the radiator, screen wash and battery can be collected in this way. Thus, an adequate supply of water to those units may be guaranteed. A sample of the collected water was tested and found to have a pH value of 6.4, i.e. substantially neutral. This further demonstrates the fitness of the collected water. 
     The automatic supply of the collected water to the units means that the vehicle owner is spared the inconvenience of having to regularly check and top up the units. Thus, the maintenance effort is beneficially reduced and the risk of breakdown is lowered. The collected water may also be used to provide a supply of drinking or washing water within the car. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention, in its various aspects, is illustrated, but not limited, by the following description of an embodiment, which refers to the accompanying drawings. 
     FIG. 1 is a schematic illustration of a water management system in accordance with the invention; 
     FIG.  2 ( a ) shows an internal view of a wet battery in accordance with the invention; 
     FIG.  2 ( b ) shows a component of the float valve of the battery of FIG.  2 ( a ); 
     FIG.  2 ( c ) is an enlarged view of the float valve of the battery of FIG.  2 ( a ); 
     FIG.  2 ( d ) shows another component of the float valve of the battery of FIG.  2 ( a ); and 
     FIG. 3 shows an external view of the battery of FIG.  2 ( a ). 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to the drawings, and first FIG. 1, there is shown a water management apparatus for a motor car. The condenser unit  1  of the car&#39;s air-conditioning system serves as a source of water supply. Water generated in the condenser unit  1  is supplied to a central storage tank  5  via a pipe  2  and filter  3 . The pipe  2  is connected to the drip outlet of the condenser unit  1 . In this embodiment, the filter  3  is a mechanical filter for removing any dust, dirt or other solid contaminant from the collected water. The filter  3  is conveniently incorporated into the cap  4  of the tank  5 . The cap includes an overflow outlet  16  for excess water to be discharged when the tank  5  is full. 
     The filtered water is fed from the tank  5 , through piping  6 , to a plurality of water storage tanks or bottles  7 ,  11 ,  13  and to a battery water reservoir  9  (see FIG.  3 ). For this purpose, a pump  33  is associated with the tank  5 . The pump may be operated automatically or by means of a control within the vehicle in order to periodically top up the supplies  7 ,  9 ,  11  and  13 . 
     A water reservoir  9 , best seen in FIG. 3, is arranged for supplying water to the car&#39;s battery  15 . The water in the reservoir  9  is allowed to drain, under the action of gravity, through a channel  23  which supplies water to the battery cells. Any excess or unrequired water  25  escapes at an outlet of the channel. The arrangement of the reservoir  9  and channel  23  for supplying water to the battery  15  will be described later with reference to FIGS. 2 and 3. 
     One water storage tank  11  is arranged for supplying water to a screen washer unit comprising one or more spray jets  27 . In FIG. 1, the jet  27  is associated with a windscreen wiper  29 . However, the jet may be equally provided for cleaning a rear window or a car light, especially a headlight. A pump  35 , which is operated by means of a switch or lever on the dashboard or steering column, serves to supply water to the jet  27  through a pipe  12  in conventional manner. 
     The tank  11  may contain a cleaning agent. Water is fed into the tank  11  from the master tank  5  via a ball-valve  18  or the like. The valve  18  is closed when the tank  11  is full, so that any further water is discharged directly through an overflow  20 . This arrangement ensures that there is no loss of cleaning agent when the tank  11  is full. Since the tank  11  is regularly filled with water from the master supply, its capacity can be made smaller than the conventional screen wash tank. 
     Another water storage tank  13  provides a supply of water for the radiator  37  of the engine&#39;s cooling system. Water is sucked up to the radiator  37  from the tank  13  through a pipe  14 . A valve  22  and overflow outlet  24  arrangement, similar to that provided for the tank  11 , ensure that any coolant agent contained in the cooling system is not lost when the tank  13  is full. 
     A further water storage tank  7  provides a supply of water for drinking, handwashing or the like by the driver and any passengers. A pump  31  serves to pump the water to an outlet through a pipe  8 , when required. The outlet is preferably located in the car interior, although it may be located elsewhere, for example in the boot. An overflow pipe  26  discharges any excess water when the tank  7  is full. 
     Each of the pipes  2 ,  6 ,  8 ,  12  and  14  which interconnect the various components of the system, suitably consists of flexible tube or hose of rubber or other water-impermeable material. 
     The storage bottles  11 ,  13  and the battery  15  are preferably disposed in their normal positions within the engine compartment, that is in positions where they are accessible for inspection and the occasional addition of screen wash detergent or engine coolant. Therefore, fitting the water management system of the invention to an existing vehicle does not require extensive modification of the layout of the components of the engine compartment. 
     FIGS.  2 ( a )-( d ) and  3  illustrate the construction of part of a wet battery in accordance with an independent aspect of the invention. In this specification, the term wet battery refers to a battery containing fluid which needs to be periodically topped up. Although the wet battery to be described is particularly suitable for use in the water management system of FIG. 1, it is not limited to such an application. 
     Referring first to FIG.  2 ( a ), the battery  15  of this embodiment has six cells arranged in a linear array in conventional manner. For the purposes of illustration, only two of the cells  61 ,  63  are shown in full in FIG.  2 ( a ). The other cells are the same. Each cell  61 ,  63  comprises a collection of plate-like electrodes  65  immersed in electrolyte fluid  67 . A structural wall  69  separates, and isolates the fluid in, the adjacent cells. 
     The upper wall of each cell is defined by the bottom of the water channel  23 , already mentioned with reference to FIG.  1 . The channel  23  extends over the line of cells to allow water, or other fluid, flowing along the channel to enter the cells as required. For this purpose, the bottom of the channel includes two apertures for each cell. Referring to the enlarged view of FIG.  2 ( c ), a first aperture serves as a gas vent, to permit gas or air to escape from the battery as required. The first aperture consists of a chimney-like structure  71 , which extends to a level above the normal water level in the channel  23 , thereby preventing unwanted entrance of water through the gas vent. Alternatively, the channel  23  may include an internal wall extending longitudinally therein to isolate the gas vents  71  from the water-receiving portion of the channel. A second aperture  81  serves as a water inlet for the cell, to permit water to enter the cell to top up the electrolyte level. This second aperture  81  consists of a hole surrounded internally by a cylindrical guide wall  73 . 
     A float valve member  75  is disposed within each cell. The float valve member  75  has three main portions: a float portion  75   a , a valve portion  75   b , and a cup portion  75   c . The float portion  75   a  extends laterally, suitably in a circular or rectangular shape, and floats on the surface of the battery fluid  67 . The float portion  75   a  is suitably made of Styrofoam (trademark). The valve portion  75   b , which is shown in detail in FIG.  2 ( b ), extends vertically from the centre of the float portion  75   a  and is supported and guided by the guide wall  73 . The distal end of the cylindrical valve portion  75   b  is terminated in a sealing disc  75   j  which internally engages the peripheral portion of the water inlet aperture  81  in a sealing manner when the valve is closed. The sealing disc  75   j  is made of a resilient and water-impermeable material. The use of silicone rubber for the sealing disc is presently preferred. 
     As best seen in FIG.  2 ( b ), the valve portion  75   b  comprises a plurality of radial vanes  75   d  extending longitudinally and spaced circumferentially. The vanes  75   d  serve to locate the valve portion  75   b  centrally within the surrounding guide cylinder  73 , and thereby form a plurality of passageways between the valve portion  75   b  and the inner surface of the wall  73 . The passageways allow the free flow of water into the cell when the valve is open. 
     This preferred configuration also prevents the accumulation of dirt such as oxide particles on the valve portion  75   b , and so ensures the free movement of the valve portion even when the fluid environment within the battery becomes contaminated as the battery ages. 
     Referring again to FIG.  2 ( b ), the valve portion  75   b  further includes a mounting disc  75   e  which provides an annular flange. The portions of the vanes  75   d  below the disc  75   e  are adapted to be received in a lower cylinder  75   h  of the cup portion  75   c.    
     FIG.  2 ( d ) shows the cup portion  75   c  of the float valve member  75 . This comprises an upper hollow cylindrical element  75   k , which is open at the top end and has a diameter greater than that of the guide wall  73 . The cup portion further comprises a lower hollow cylindrical element  75   h  of a diameter which is smaller than that of the upper element  75   k  and slightly greater than that of the valve portion  75   b . The lower cylindrical element  75   h  is closed at its bottom end. 
     As best seen in FIG.  2 ( c ), the lower element  75   h  accommodates the lower portion of the valve body  75   b . The flange of the disc  75   e  is seated on the step which joins the upper and lower cylindrical elements  75   k ,  75   h . The disc flange is preferably sealingly fixed to the step, for example by using adhesive. 
     The lower portion of the upper cylindrical element  75   k  includes a plurality of fluid holes  75   g . The fluid holes  75   g  are formed in the cylinder wall, at a certain height above the step. 
     The vertical movement of the float valve member  75  is limited in the downward direction by interlocking of the cup portion  75   c  with the guide wall  73 . For this purpose, in this embodiment, the lower end of the guide wall terminates in an annular lip  73   a  (see FIG.  2 ( c )), while the top, open end of the cup portion  75   c  includes a plurality of internal lugs  75   f  (see FIG.  2 ( d )). When the float valve member  75  drops below a predetermined level, the lugs  75   f  (there are two by way of example in the present embodiment) latch onto the guide wall lip  73   a  to arrest further downward movement. The vertical movement in the upward direction is limited by the engagement of the sealing disc  75   j  with the water inlet aperture  81  when the valve is in the closed state. 
     It will be noted that guide wall  73  and the wall of the upper element  75   k  of the cup portion form a continuous vertical barrier extending from the cell ceiling to the valve float portion  75   a . This arrangement serves to prevent the escape of fluid from the cell (via the said second aperture), especially during vibration when the vehicle is in motion. Any fluid which does enter the cup portion will, however, flow out through the holes  75   g  therein when the fluid exceeds the level of those holes. As a further safeguard against the escape of fluid, a cylindrical baffle wall  77  extends vertically down from the cell ceiling to surround the upper part of the valve member  75 . The arrows  79  indicate the function of the baffle wall  77  in deflecting any fluid that splashes upwards within the cell. 
     The inclusion of the cup portion  75   c  is optional, since the valve will operate without it. However, it is preferred for the reasons and advantages set out herein. 
     FIG. 3 is a perspective view of the top of the battery showing the channel  23  and reservoir  9  mentioned already with reference to FIG.  1 . In this embodiment, the channel  23  and the reservoir  9  are formed as an integral box-like structure  39 , which is conveniently made as a plastic moulding. An internal wall  41  divides the structure into the fluid reservoir  9  and the supply channel  23 . The upper wall of the box may be removable or openable (not shown), especially over the channel  23  to permit inspection. The box is preferably also made of clear plastic for this purpose. The portion of the upper wall or lid over the channel encourages condensation of any battery fluid vapour escaping from the vents  71 . The condensate usefully collects in the bottom of the channel and thus may reduce the amount of water that needs to be supplied from the reservoir. 
     Water is pumped into the reservoir  9  by the pump  33  (see FIG. 1) through an inlet  43  and enters the channel  23  therefrom via a port  45  formed in the wall  41 . The water flows down the channel  23  and enters each cell of the battery whose fluid level is such that the float valve aperture  81  is open. Any excess water exits from the outlet  47 , from where it may be wasted or returned to the reservoir  9  or tank  5 . It is not essential to fill the reservoir  9  automatically. In an application where a water management system such as that shown in FIG. 1 is not employed, a manual filling port  49  and associated plug  51  can be provided. In that case, the inlet  43  is either plugged or not provided at all. 
     The reservoir  9 , channel  23  and float valve members  75  may be constituted as a cover assembly to be fitted to the body of a conventional battery, thereby enabling the battery manufacturer to fabricate a battery in accordance with the invention without the need to re-design or re-tool the body of the battery. 
     In operation, water is fed into the channel  23  through the port  45  and travels down the channel toward the end having the outlet  47 . For any cell of the battery in which the fluid level is below a predetermined value, the float valve member  75  will drop down to open a gap between the aperture  81  and sealing disc  75   j . Thus, the water will enter this cell through the gap. 
     The water flows down between the guide wall  73  and the valve body  75   b , enters the bottom of the cup  75   c  and exits through the fluid holes  75   g , thereby topping up the cell fluid level. When the fluid level has risen again to the reference value, the float valve member  75  will also reside at a higher level to close the gap thereby preventing further water entry. The fluid level in each cell is self-regulated in this way. The cells may be topped up, as required, either in sequence or simultaneously, depending on the speed of the water flow through the channel. The water may be supplied to the channel  23  continuously or periodically. In the system of FIG. 1, the reservoir  9  is periodically charged, whether by manual instruction or automatically, and then allowed to empty over a short period, suitably a few minutes. This intermittent mode of operation is preferred to using a continuous flow of water. Especially, the intermittent flow of water can be generated when the vehicle is not in motion, which prevents accidental opening of the cell valves and unwanted entry of water due to vibration or shock. 
     The advantages of the described construction of the wet battery include the following. The provision of the common channel serving to supply the water to all the battery cells means that there is no need to interconnect the individual cell valves. Also, as compared with using a hose connection, the channel is easily accessible, less liable to blockage and simple to clean. Building the float valves into the structure of battery body enables each float member to occupy the full width of the cell. This improves the weight of the float valve member and the response to changes in the fluid level. The construction of the valves is simple and therefore of low cost, yet reliable. The water used to top up the cells does not need to be pressurised, nor supplied continuously. 
     The water management system of the invention is suitable for use on any vehicle including car, electric car, lorry, bus, train, boat, ship and various kinds of aircraft. Any one or more units requiring a water supply may be incorporated. It is not essential to supply water to the four units of the example, although in the case of the car, it is convenient to do so. Some modern vehicle batteries are completely sealed and do not require water top up. Here, the system remains suitable for any or all of the radiator, screen wash and drinking supplies. The wet battery of the invention has application in the above vehicles plus vehicles such as fork lift trucks and milk floats which use electrical power for their traction and/or other functions. The battery of the invention is equally useful in applications outside of the field of vehicles, such as emergency and stand-by power supplies.