Abstract:
An internal combustion engine/water source system for a vehicle powered by a internal combustion engine wherein liquid water is produced by cooling a portion of engine exhaust gases in a vortex tube to induce condensation. In one embodiment, engine exhaust gases are pumped into the vortex tube by a compressor. After removing a portion of water vapor, cooled exhaust gases may be re-introduced to engine&#39;s combustion chamber thereby providing an exhaust gas recirculation. In an automotive vehicle, liquid water generated by the invention may be collected and provided to an electrolytic cell for electrolysis into gaseous hydrogen to reduce exhaust pollutants during cold engine start. Alternatively, water generated by the invention may be injected into engine combustion chamber to increase power and to reduce production of nitrogen oxides.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a continuation in-part of prior U.S. application Ser. No. 11/178,517 filed on Jul. 11, 2005 and entitled INTERNAL COMBUSTION ENGINE/WATER SOURCE, the entire contents of which is hereby expressly incorporated by reference. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates to an apparatus and method for providing liquid water on-board a vehicle powered by an internal combustion engine and more particularly to supplying water for 1) reducing pollution during cold engine start-up, 2) injection into engine cylinders for improved performance, and 3) reducing turbocharger lag.  
       BACKGROUND OF THE INVENTION  
       [0003]     There are numerous motivations for producing water onboard a vehicle powered by an internal combustion engine. One such motivation is to provide feedstock for electrolytic generation of hydrogen gas which, during a startup, can be fed into the intake of an internal combustion engine (ICE) to reduce engine wear and/or into an engine exhaust system to reduce pollutants. Another such motivation is injection of water into engine cylinders to increase power output at times of increased demand. Yet another motivation is production of steam for acceleration of turbochargers and reduction of turbocharger response time lag.  
         [0004]     Challenges of Cold ICE Startup: There are several problems that must be overcome during the start-up of a cold ICE. First, atomized or vaporous fuel in the air/fuel mixture introduced into the engine cylinders tends to condense onto the cold engine components, such as cylinder walls and the air intake rail. Such a condensate may act as solvents that wash away desirable lubricant films resulting in excessive mechanical wear from reciprocating piston rings in sliding contact with the engine cylinder walls. Second, the condensation of atomized or vaporous fuels onto cold engine cylinder walls may result in poor engine performance and delayed engine availability during and immediately after cold engine start-up. ICE availability may be diminished during cold engine start-up due to poor lubricant properties at low temperatures, non-uniform fuel distribution and improper air/fuel mixtures. Third, if the vehicle is equipped with a catalytic converter increased levels of unwanted pollutants may be emitted from the tailpipe for a period of about one minute after cold engine start-up because that is the amount of time normally needed for the ICE exhaust gases to heat the catalytic converter in the exhaust system to an efficient operating temperature.  
         [0005]     The undesirable levels of pollutants released during and immediately after cold engine start-up in automotive vehicles present a problem of increasing importance. In order to meet increasingly stricter governmental engine emission standards, a catalytic converter is usually located in the exhaust stream of the engine. The conventional method of heating the catalytic converter to its efficient operating temperature is to heat the catalyst by passing high temperature exhaust gases from the ICE through the catalyst. Convection heating by exhaust gas in conjunction with the exothermic nature of the oxidation reactions occurring at the catalyst, will usually bring the catalyst to an efficient operating temperature, or “light-off” temperature, in about one minute. However, until the catalyst light-off temperature is reached, the ICE exhaust gasses pass through the catalytic converter relatively unchanged, and unacceptably high levels of pollutants such as carbon monoxide, hydrocarbons and nitrogen oxides are released into the atmosphere. According to some estimates, automotive vehicles having ICE equipped with catalytic converter generate over 80% of the unacceptable emissions or pollutants during cold start operations.  
         [0006]     One promising solution to the cold engine start problem is addition of gaseous hydrogen into the fuel mixture before combustion as disclosed, for example, by Andrews et al. in U.S. Pat. No. 6,427,639 and by Murphy et al. in U.S. Pat. No. 6,122,909. When mixed and combusted with engine fuel, the gaseous hydrogen enhances the flame velocity and permits the engine to operate with leaner fuel mixtures. Thus, hydrogen has a catalytic effect causing a more complete burn of the existing fuel and yields a reduction in exhaust emissions. Pollutants may be also reduced by post treatment of ICE exhaust gases by addition of hydrogen as disclosed, for example, by Benninger et al. in U.S. Pat. No. 6,810,657.  
         [0007]     Due to the advantages of using hydrogen for reducing ICE exhaust emissions and engine wear during cold startup, a number of attempts have been made to incorporate a hydrogen gas supply system with automotive vehicles. However, providing hydrogen gas as a separate fuel at automotive service stations is impractical because hydrogen distribution infrastructure for automotive use is non-existent. In addition, transport and storage of large quantities of hydrogen represent a very significant safety hazard. This situation may be overcome by producing hydrogen gas directly on board an automotive vehicle by electrolysis of water as disclosed, for example by Andrews et al. in U.S. Pat. No. 6,698,389 and Zagaja et al. in U.S. Pat. Nos. 6,857,397 and 6,659,049. To sustain appropriate hydrogen production rates requires a reliable source of liquid water.  
         [0008]     Injection of Water into ICE Combustion Chamber: It is well known in the art that injection of water into ICE combustion chambers reduces flame temperature which translates to reduced NOx emissions. In addition, experiments show that water injection may significantly boost ICE output power.  
         [0009]     Turbocharger Response Time Lag: Turbochargers operated by exhaust gas have long been utilized for boosting the power output of ICE&#39;s. An exhaust gas turbocharger typically includes a turbine and a centrifugal compressor on a common shaft. The turbine is rotated by exhaust gases from the engine and spins the compressor. The compressor receives intake air, compresses it, and supplies it to ICE combustion chamber(s). Turbochargers provide the advantages of relatively smooth transitions from natural aspiration to supercharged operation while utilizing some of the residual energy of hot exhaust gas, which would otherwise be largely wasted. One drawback of a turbocharged engine is a slow response time known as the “turbo-lag” which is caused by the low pressure and low quantity of exhaust gases at low engine speeds. Quick acceleration of the turbocharger to normal operating speed is further impeded by the turbocharger rotational inertia. Consequently, a standard exhaust gas turbocharger is effective only above about 1800 rpm of the ICE. This means that an ICE equipped with a turbocharger is susceptible to insufficient torque at low engine speeds. An attractive solution recently disclosed by Chomiak in U.S. Pat. No. 6,883,325 uses a steam generated from boiling water to form a jet directed onto the turbine wheel to accelerate the turbocharger. Other uses of water in an automotive vehicle may include replenishment of water in ICE coolant, replenishment of water in windshield washing fluid, and humidity control in passenger compartment.  
         [0010]     ICE Exhaust Gas as a Potential Source of Water: It has been earlier recognized that ICE exhaust gases contain a significant amount of water vapor which originates primarily from combustion of fuels containing hydrocarbons. In particular, Andrews et al. in U.S. Pat. No. 6,804,949 teaches that under typical operating conditions ICE exhaust gas stream may contain approximately 12% CO 2 , 16% H 2 O and 72% of other (mostly nitrogen and inert) gases by volume. Since the ICE exhaust gases may be very hot (typically well over 300 degrees Centigrade), all of the water contained therein may be in the form of vapor. In particular, at sea level (760 Torr total ambient pressure) the partial pressure of water vapor in the ICE gases is about 118 Torr, which translates to a dew point of 55 degrees Centigrade (131 degrees Fahrenheit).  
       EXAMPLE 1  
       [0011]     To illustrate the potential of ICE exhaust gases as a source of water one may consider an automotive vehicle with an ICE moving at about 100 kilometers per hour (65 miles per hour) and consuming about 1.5 grams of fuel per second. Combustion of fuel at this rate is estimated to generate about 2.1 grams of water vapor per second which translates to about 7.7 kilograms of water per hour. Benz et al. in U.S. Pat. No. 5,658,449 estimates that to support hydrogen production, water should be supplied to an electrolytic cell at a rate of about 35 grams per hour. It is evident that hydrogen production needs on-board the automotive vehicle could be comfortably met by converting only a very small fraction (about 0.5%) of the total available water content in ICE exhaust into liquid water.  
         [0012]     It is well known that water condensate forms when gases containing water vapor are cooled to below the dew point. Since ICE exhaust gases passing through an automotive exhaust system are rather hot, they must undergo a very significant cooling before precipitation of liquid water is induced. Information relevant to attempts these problems can be found in U.S. Pat. Nos. 6,804,949, 6,857,397 and 6,659,049. However, each one of these references suffers from one or more of the disadvantages discussed below. In particular, Andrews et al. in U.S. Pat. No. 6,804,949 discloses a method for production of water from ICE exhaust gases wherein ICE exhaust gases are cooled either by ambient air, of by ICE coolant, or by a vapor compression heat pump. However, cooling of exhaust gases to a dew point by ambient air is rather ineffective on hot days when the ambient air temperature approaches the dew point of ICE exhaust gas. Cooling of exhaust gases to a dew point by ICE coolant is effective only during the brief period of ICE startup because the ICE coolant temperature in a fully warmed up engine is typically maintained at about 100 degrees Centigrade. Cooling of exhaust gases to a dew point by a vapor-compression heat pump is not attractive because it requires that an air-conditioning system is actually installed in the vehicle and that it is operated even at times when not necessary for the comfort of vehicle occupants. The latter would undoubtedly result in a very significant wear on the air-condition system and reduced fuel efficiency of the automotive vehicle. Zagaja et al. in U.S. Pat. Nos. 6,857,397 and 6,659,049 discloses a method of cooling ICE exhaust gases using a thermo-electric cooler (TEC). However, TEC is expensive and far less thermodynamically efficient than a vapor compression heat pump, requires significant amount of electric power to operate, and generates significant amount of waste heat that must be rejected.  
         [0013]     Vortex Tube: Vortex tube is a well known cooling device in the art of refrigeration. Traditional vortex tube comprises a slender tube having one end closed except for a small a central opening and the other end plugged except for an annular opening which may be adjusted in size for flow control, see  FIG. 1 . A stream of high-pressure air (or other suitable gas) may be injected through an inlet port tangentially into the tube in the proximity of the central opening. Resulting vortex flow pattern inside the tube separates the input air stream into a relatively hot air stream which exits through the annular opening and a relatively cold air stream which exits through the central opening and the cold outlet port. Relative flow rates and temperatures of these two streams are typically adjustable by controlling the flow of the hot exhaust stream. See, for example, article entitled “The Vortex Tube as a Classic Thermodynamic Refrigeration Cycle,” by B. K. Ahlbom et al., published in Journal of Applied Physics, Volume 88, Number 6, pp. 3645-3653, Sep. 15, 2000. A variant of the traditional vortex tube suitable for generating only a cold output stream can be produced by entirely closing one of the tube ends combined with active cooling of the tube exterior surface such as shown in  FIGS. 2A and 2B  and disclosed, for example, by Zerr in U.S. Pat. No. 4,612,646. Suitable cooling may be provided by a cooling jacket which may envelop the exterior surface of the tube. Suitable coolants may be provided in liquid or gaseous form. The exterior surface of the tube can be further provided with surface extensions to facilitate improved heat transfer into the coolant as disclosed, for example, by Tunkel et al. in U.S. Pat. No. 5,911,740. Thermodynamic action inside the vortex tube deposits heat into the tube&#39;s cooling jacket and it cools the air inside the tube. Vortex tube may also discharge flow into regions of pressures below atmospheric pressure as disclosed, for example, by B. R. Belostotskiy et al. in an article “Vortex-Flow Cooled Laser,” published in Soviet Journal of Optical Technology, volume 35, number 1, pp. 450-452, January-February 1968, and by Tunkel et al. in U.S. Pat. No. 5,561,982. Data of some vortex tube manufacturers suggests that the pressure ratio between vortex tube inlet port and its cold outlet port should be at least 1.4; see, for example, Catalog No. 21, page 102, published by Exair Corporation, Cincinnati, Ohio. Data from vortex tube manufacturers indicates that the practical limit to the reduction in air temperature achievable by a single stage vortex tube is about 70 degrees Centigrade. Vortex tube research data suggests that pressure ratio higher than 8 may cause undesirable pressure shocks inside the vortex tube (see, e.g., B. K. Ahlborn, supra). This suggests that a preferred value for vortex tube pressure ratio should be between about 1.4 and about 8.  
         [0014]     Holman et al. in the U.S. Pat. No. 6,895,752 discloses a turbocharged ICE with an exhaust gas recirculation (EGR) system wherein ICE exhaust is directed to a vortex tube to generate a cooler flow and a hoter flow. The cooler flow is directed to ICE intake to recirculate part of the exhaust gas. It is well known that exhaust gases from an ICE may have a temperature generally in the range of 800 to 1,200 degrees Centigrade. Because a single stage vortex tube can only cool gases by about 70 degrees Centigrade and no other cooling means are disclosed by Holman, it may be concluded that the cold output flow from Holmes&#39; vortex tube delivers exhaust gases having a temperature of several hundred degrees Centigrade which is excessively high for condensation of water from a water vapor with a dew point of 55 degrees Centigrade. As a result, Holmes&#39; apparatus is not suitable for production of liquid water from water vapor contained in ICE exhaust gas.  
         [0015]     In summary, the referenced art does not teach an ICE system with a water source that is simple and inexpensive to operate. Consequently, there is a great need for new devices and methods for extracting liquid water from ICE exhaust gases. Suitable water source should use very little motive power so as not to significantly reduce vehicle mileage, it should be capable of operating without human intervention in hot, cold, dry, or wet climates and under any weather conditions including freezing conditions, it should be robust to vibrations, and it should be inexpensive to manufacture and integrate into automotive vehicles.  
       SUMMARY OF THE INVENTION  
       [0016]     The present invention provides an ICE/water source system wherein the water vapor from ICE exhaust gases is condensed into liquid water. A portion of ICE exhaust gases is separated from ICE exhaust gas stream and cooled in a vortex tube to below its dew point. Liquid water generated by the water source may be provided to an electrolytic cell for generation of hydrogen gas, and/or to an injector for delivery into engine combustion chambers, and/or to a steam generator for production of steam to accelerate a turbocharger. Alternate uses of liquid water generated by the water source of the subject invention may include replenishment of water in windshield washing fluid reservoir, replenishment of water in ICE coolant system, and providing a feedstock to a passenger compartment humidifier.  
         [0017]     A first embodiment of the present invention may take advantage of the pressure difference between the ICE exhaust and intake passages to operate a vortex tube. In particular, a portion of the ICE exhaust gas is drawn from ICE exhaust duct and pre-cooled in a heat exchanger followed by cooling to below a dew point in a vortex tube. Liquid water is separated from the gases and provided to a reservoir. Exhaust gases with reduced water vapor content separated from liquid water may be drawn into ICE intake or into a suitable source of low pressure.  
         [0018]     A second embodiment of the present invention is substantially the same as the first embodiment except that it may also include a compressor which increases the pressure of exhaust gases before they enter the vortex tube. This allows the vortex tube to operate at a higher pressure ratio than in the first embodiment and generate more effective cooling. The compressor can be directly driven by the ICE, vehicle propulsion shaft, air motor, electromagnet, electric motor, or other suitable means. Compression significantly increases a dew point of the ICE exhaust gases. This makes it less challenging to cool the compressed exhaust gases to below the point and induce condensation into liquid water.  
         [0019]     A third embodiment of the present invention is particularly suitable for turbocharged ICE. In a turbocharged ICE the exhaust pressure upstream the turbocharger is significantly higher than ambient atmospheric pressure and this pressure head may be used to operate the vortex tube. According to a third embodiment of the present invention, a portion of ICE exhaust gases is drawn from ICE exhaust duct upstream of the turbocharger, pre-cooled in a heat exchanger, and cooled to below its dew point in a vortex tube. Condensed liquid water is substantially separated from gases and collected in a reservoir.  
         [0020]     Accordingly, it is an object of the present invention to provide a ICE/water source system which can reliably generate liquid water onboard a vehicle. The ICE/water source system of the present invention has a low energy consumption, is simple, lightweight, and inexpensive to manufacture and, therefore, suitable for large volume production of automotive vehicles.  
         [0021]     It is another object of the present invention to provide a ICE/water source system that is operational at all atmospheric conditions, that is robust to freezing conditions, and can operate automatically without human intervention.  
         [0022]     It is yet another object of the present invention to provide a ICE/water source system that can supply liquid water to an electrolytic cell for production of gaseous hydrogen that can be injected into ICE intake to improve operation during ICE startup.  
         [0023]     It is still another object of the present invention to provide a ICE/water source system that can supply liquid water to an electrolytic cell for production of gaseous hydrogen that can be injected into ICE exhaust to reduce pollutants during ICE startup.  
         [0024]     It is a further object of the present invention to provide a ICE/water source system that can supply liquid water for delivery into ICE combustion chambers.  
         [0025]     It is a yet further object of object of the present invention to provide a ICE/water source system that can supply liquid water to a steam generator that provides steam for acceleration of a turbocharger.  
         [0026]     It is a still further object of object of the present invention to provide a ICE/water source system that can supply liquid water to ICE coolant system.  
         [0027]     It is an additional object of object of the present invention to provide a ICE/water source system that can supply liquid water to vehicle windshield washing system. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0028]      FIG. 1  is a cross-sectional view of a vortex tube of prior art suitable for concurrent generation of hot and cold output streams.  
         [0029]      FIG. 2A  is a cross-sectional view of a vortex tube of prior art suitable for generation of cold output stream only.  
         [0030]      FIG. 2B  is a cross-sectional view of an alternative vortex tube of prior art suitabled for generation of cold output stream only.  
         [0031]      FIG. 3  is a schematic depiction of the ICE/water source system in accordance with a first embodiment of the subject invention.  
         [0032]      FIG. 4  is a schematic depiction of the ICE/water source system in accordance with a second embodiment of the subject invention.  
         [0033]      FIG. 5  is a schematic depiction of the ICE/water source system in accordance with a third embodiment of the subject invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0034]     Selected embodiments of the present invention will now be explained with reference to drawings. It will be apparent to those skilled in the art from this disclosure that the following descriptions of the embodiments of the present invention are merely exemplary in nature and are in no way intended to limit the invention, its application, or uses.  
         [0035]     Referring to  FIG. 3 , there is shown schematically an internal combustion engine (ICE)/water source system  10  in accordance with a first embodiment of the subject invention. The ICE/water source system  10  comprises an ICE assembly  15  and a water source assembly  100 . The ICE assembly  15  further comprises an ICE  20 , intake duct  32 , and exhaust duct  46 . The ICE  20  may be of any suitable type adapted for combusting a hydrocarbon-based fuel. For example, the ICE  20  may be a reciprocating type engine having either a compression ignition, spark ignition, or homogeneous charge compression ignition (HCCI). The ICE  20  may further include a combustion chamber  34 , an intake passage  22 , and an exhaust passage  24 . The intake passage  22  is fluidly connected to the intake duct  32  and adapted for receiving intake air therefrom. Furthermore, the intake passage  22  is fluidly connected to the combustion chamber  34  and adapted for flowing intake air threinto. The exhaust passage  24  is fluidly connected to the combustion chamber  34  and adapted for flowing exhaust gases therefrom. Furthermore, the exhaust passage  24  is fluidly connected to the exhaust duct  46  and adapted for flowing exhaust gases thereinto. In an ICE having multiple combustion chambers the intake passage  22  may be formed as an intake manifold and the exhaust passage  24  may be formed as an exhaust manifold. The ICE assembly  15  may also include an electrolytic cell for generation of hydrogen by electrolysis of water, and/or an ICE coolant system, and/or a windshield washing system, and/or a system for injection of liquid water into combustion chamber  34 , and/or a system for generation of steam for delivery to a turbine portion of a turbocharger. The water source assembly  100  may further comprise a heat exchanger  128 , vortex tube  120 , gas-liquid separator  136 , reservoir  130 , and interconnecting lines  112 ,  114 ,  116 ,  118 , and  122 .  
         [0036]     The heat exchanger  128  is adapted for cooling exhaust gases and it may assume a variety of suitable forms practiced in industry. In particular, the heat exchanger  128  may be adapted for transfering heat from exhaust gases into ICE liquid coolant. ICE liquid coolant is preferably provided at a temperature of less than about 100 degrees Centigrade. Most preferably, ICE liquid coolant is provided at a temperature between about 30 and about 60 degrees Centigrade. Alternatively, the heat exchanger  128  may be cooled by ambient air or other suitable means. For example, if the subject invention is used in an automotive vehicle, the heat exchanger  128  (if air cooled) may be located in such a portion of the vehicle where it is exposed to a stream of ambient air induced by the vehicle motion. The heat exchanger  128  has an upstream port fluidly connected to the exhaust duct  46  by means of line  112  and a downstream port fluidly connected to line  114 . Line  112  may also include a filter for removal of particulates and a flow control valve (not shown). The vortex tube  120  comprises an inlet port  172  and a cold outlet port  174 . Preferably, the vortex tube  120  is of the type adapted for generation of cold air only such as shown in  FIGS. 2A and 2B  and described in connection therewith. Most preferably, the configuration of vortex tube  120  conforms to  FIG. 2B . The vortex tube  120  may also have a cooling jacket (see  FIGS. 2A and 2B ) which may be cooled by ICE coolant, or by ambient air, or by other suitable means. If ICE coolant is used, it is preferably supplied at a temperature between about 30 and about 60 degrees Centigrade. Preferably, the body of the vortex tube  120  is maintained at a temperature above zero degrees Centigrade to prevent moisture contained in the gases entering the tube from freezing onto tube walls. The design of vortex tube  120  may also include a provision to reduce susceptibility to plugging by ice formed from the residual moisture in the inlet air. Suitable non-freezing vortex tube has been disclosed by Tunkel at al. in U.S. Pat. No. 6,289,679. The inlet port  172  is fluidly connected to the downstream port of heat exchanger  128  via line  114 . The cold outlet port  174  is fluidly connected by line  116  to the separator inlet port of gas-liquid separator  136 . An alternative vortex tube for use with the subject invention may have a conventional design for concurrent generation of hot and cold outlet streams such as shown in  FIG. 1  and described in connection therewith. In such case the vortex tube also includes a hot outlet port which may be fluidly connected to line  118 . In addition, such a vortex tube may reject heat into the gas discharged through the hot outlet port. Another alternate vortex tube suitable for use with the subject invention has been disclosed by Cho et al. in U.S. Pat. No. 6,494,935. Cho&#39;s vortex tube has the capacity to act as a gas-liquid separator and it may also include a liquid outlet port. Regardless of the type of vortex tube, one or more vortex tubes may be employed in the subject invention. Multiple vortex tubes may be connected in parallel to increase gas through put or in series to increase overall temperature drop in cooled gas.  
         [0037]     The gas-liquid separator  136  is adapted for receiving a mixture of gas and liquid through the separator inlet port, substantially separating liquid from the gas, delivering separated liquid substantially free of gas to its liquid output port, and delivering gas substantially free of liquid to its gas outlet port. Gas-liquid separation devices suitable for use with the subject invention may include impingement separators and centrifugal separators such as cyclones and vortex tubes (see, for example, the already mentioned U.S. Pat. No. 6,494,935 to Cho et al. and the U.S. Pat. No. 5,976,227 to Lorey). Certain suitable gas liquid separator may be also found, for example, in Chemical Engineer&#39;s Handbook, 5 th  edition, edited by Robert H. Perry and Cecil H. Chilton, published by Mc-Graw-Hill Book company, New York, N.Y., 1973, chapter 18, section titled “Phase Separation.” The liquid output port of separator  136  may be fluidly connected to the reservoir  130  by means of line  122 . The gas output port of separator  130  may be fluidly connected to intake duct  32  by means of line  118 . It may be noted that in the configuration shown in  FIG. 3 , the exhaust duct  46  is fluidly connected to the intake duct  32  by means of the heat exchanger  128 , vortex tube  120 , gas-liquid separator  136  and lines  112 ,  114 ,  116  and  118 , Alternatively, the gas output port of gas-liquid separator  136  may be fluidly coupled to a suitable source of vacuum such a suction port of a vacuum pump. As a yet another alternative which may be suitable for ICE having a sufficiently high pressure of exhaust gases inside the exhaust duct  46 , the gas output port of separator  136  may be in fluid communication with ambient atmosphere.  
         [0038]     The reservoir  130  is a vessel adapted for collection of liquid water. Line  122  fluidly connects liquid outlet port of separator  136  to reservoir  130 . The lower portion of the reservoir  130  is fluidly connected to a transfer line  178  leading to destinations for water delivery such as an electrolytic cell for generation of hydrogen by electrolysis of water, and/or an ICE coolant system, and/or a windshield washing system, and/or a system for delivery of liquid water into combustion chamber  34 , and/or a system for generation of steam for delivery to a turbine portion of a turbocharger, and/or a humidifier for passenger compartment. Line  178  may also include a cation/anion exchange bed and/or other suitable means to remove contaminants and/or odors from water drained from reservoir  130 .  
         [0039]     During normal operation of the ICE/water source system  10 , intake air stream  44  flows through the intake duct  32  and through the intake passage  22  into the combustion chamber  34 . Furthermore, hydrocarbon-based fuel is supplied into the combustion chamber  34  and it is substantially combusted therein. Combustion products are exhausted from the combustion chamber  34  through the exhaust passage  24  into the exhaust duct  46  where they form an exhaust gas stream  92 . As already noted above, products of hydrocarbon-based fuel combustion are very rich in water vapor. At normal operating conditions of the ICE system  15 , the pressure p E  in the exhaust duct  46  may be substantially higher than the ambient atmospheric pressure and the pressure p I  in the intake duct  32  may be substantially lower than the ambient atmospheric pressure. As a result, there exists a substantial pressure difference Δp between the pressure p E  in the exhaust duct  46  and the pressure p I  in the intake duct  32 . In particular, Δp=p E −p I . As already described above, the exhaust duct  46  may be fluidly connected to the intake duct  32 . Therefore, the pressure difference Δp provides a motivation for a portion of the exhaust gas stream  92  to flow from the exhaust duct  46  into the intake duct  32  by following a path through the heat exchanger  128 , vortex tube  120 , gas-liquid separator  136 , and interconnecting lines  112 ,  114 ,  116 , and  118 .  
         [0040]     In particular, a portion of exhaust gases  92  flows from the exhaust duct  46  into line  112  thereby forming a process stream  142 . Line  112  may include a filter which may substantially remove soot and particulates from the process stream  142 . The process stream  142  is drawn through line  112  into the upstream port of heat exchanger  128 . The heat exchanger  128  reduces the temperature of the process stream  142  to preferably less than 120 degrees Centigrade, thereby producing a cooler process stream  148  which exits through the down stream port of heat exchanger  128  into line  114 . Most preferably, the temperature of the cooler process stream  148  is between 30 and 60 degrees Centigrade. The heat exchanger  128  may reject heat to ICE coolant, ambient air, or other suitable medium. The process stream  148  is drawn through line  114  and into the inlet port  172  of vortex tube  120  and it is cooled in the vortex tube to below its dew point, thereby forming a process stream  150  which exists the vortex tube through the cold outlet port  174 . Cooling action inside the vortex tube  120  causes some of the water vapor herein to condense into liquid. A portion of the condensate may be in a form very small droplets which may be entrained by the gas flow. Some of the condensate may become separated from the gas flow by centrifugal forces and may become collected on the interior walls of the vortex tube  120 . Preferably, the vortex tube  120  is designed and mounted so that liquid condensate is drained from the tube&#39;s interior walls by gravity into the cold outlet port  174 . The process stream  150  which may contain both gaseous and liquid components exits the vortex tube through the cold outlet port  174  into line  116  and therethrough into the separator inlet port of gas-liquid separator  136 . Inside the gas-liquid separator  136  the gas and liquid portions of the process stream  150  are substantially separated into a process stream  138  containing primarily gases and vapors and a process stream  146  containing primarily liquid water. Process stream  138  flows from the gas-liquid separator into line  118  and therethrough into the intake duct  32 . Preferably, the gas-liquid separator  136  is designed and mounted so that process stream  146  may be drained by gravity into line  122  and therethrough into the reservoir  130  where the condensed water accumulates in a pool  144 . As already stated above, in a variant of the invention the downstream end of line  118  may be fluidly connected to a source of sufficiently low pressure such as an inlet port of a vacuum pump rather than the intake duct  32 . In such case, process stream  138  may flow from the gas-liquid separator into line  118  and therethrough into the source of sufficiently low pressure. If the vortex tube  120  has a gas-liquid separation capability, the gas-liquid separator  136  may be omitted and the liquid outlet port of such a vortex tube may be fluidly connected to the reservoir  130 . The gas outlet port of such a vortex tube may be fluidly connected to intake duct  32  or a suitable source of sufficiently low pressure.  
       EXAMPLE 2  
       [0041]     Consider a hypothetical ICE/water source system  10  operated at a sea level with ambient atmospheric pressure of  760  Torr and at an ambient temperature of 40 degrees Centigrade (104 degrees Fahrenheit). To limit ICE pumping loss, ICE designers normally strive to keep the pressure drop in the exhaust duct  46  very small. This means that the pressure inside the exhaust duct  46  may be only slightly higher than the ambient atmospheric pressure. It may be assumed that the pressure in the exhaust duct at a point where it connects to line  112  is about 850 Torr. It may be also assumed that the pressure inside the intake duct is about 600 Torr or lower. Assuming that the exhaust gas stream  92  has a 850 Torr total pressure and it contains 16% water vapor by volume, the partial pressure of the water vapor therein is about 136 Torr which translates to a dew point of about 58 degrees Centigrade. Consider a process stream  142  being drawn from exhaust gas stream  92  and cooled in the heat exchanger  128  to a temperature of 60 degrees Centigrade. Because this temperature is above the dew point of 58 degrees Centigrade, no condensation is expected to occur in the heat exchanger  128 . Cooled process stream  148  is be delivered from the heat exchanger  128  to the vortex tube  120 . At the stated conditions, pressure ratio of the vortex tube is about 1.4. According to Exair Catalog No. 20, supra, a traditional vortex tube such as shown in  FIG. 1  operated at 80% cold fraction and a pressure ration of 1.4 may reduce the temperature of inlet air by 15.6 degrees Centigrade. Therefore, it may be concluded that the temperature of process stream  150  leaving the vortex tube  120  is about 45 degrees Centigrade which is well below the dew point of 58 degrees Centigrade. As a result, water vapor in process stream  150  may condense into liquid water until the partial pressure of the residual water vapor drops to about 72 Torr, which is the partial pressure of water vapor that corresponds to a dew point of 45 degrees Centigrade. The fraction of the water vapor originally contained in process stream  142  that may be liquified in this process is estimated at (136−72)/136=0.47.  
         [0042]      FIG. 4  shows an ICE/water source system  11  in accordance with a second embodiment of the subject invention. The ICE/water source system  11  comprises an ICE assembly  15  and a water source assembly  101 . ICE assembly  15  may be of the same design and construction as the ICE assembly  15  used in the first embodiment and shown in  FIG. 3 . The water source assembly  101  may be substantially the same as the water source assembly  100  except that it further includes a compressor  140  disposed between the heat exchanger  128  and the vortex tube  120 . The compressor  140  includes a suction port and a discharge port. The suction port of compressor  140  is fluidly connected to the downstream port of heat exchanger  128  by means of line  114 ′. The exhaust port of compressor  140  is fluidly connected to the inlet port  172  of vortex tube  120  by means of line  154 . Compressor  140  may be of any suitable type including a piston compressor, diaphragm compressor, vane compressor, scroll compressor, roots blower, and turbo-compressor. Compressor  140  may be operated by an electric motor, ICE output shaft, air motor, turbine, vehicle drive shaft, or other suitable means. For example, the compressor  140  may be driven from the output shaft of ICE  20  by means of a belt, pulleys and a clutch (not shown). The clutch may be engaged or disengaged to operate the compressor  140  in accordance with demand for liquid water and/or ICE operating conditions. In a variant of the second embodiment, the downstream end of line  118  may be connected to the exhaust duct  46  or to a suction port of a vacuum pump, or it may be open to atmosphere instead of being connected to the intake duct  32  as shown in  FIG. 4 .  
         [0043]     The ICE/water source system  11  operates in a similar manner as the ICE/water source system  10  with the notable exception that the compressor  140  now receives the process stream  148  and compresses it to produce a high-pressure process stream  166 . The high-pressure process stream  166  flows through line  154  to the inlet port  172  of vortex tube  120  where its is cooled in a similar manner as in the water source assembly  100  except that the vortex tube  120  may now operate at a pressure ratio significantly higher than 1.4 and thus generate more cooling power. Line  154  may also include an aftercooler or other suitable cooling device to remove the heat added to the flow by the compressor  140 .  
         [0044]     Referring now to  FIG. 5  there is shown an ICE/water source system  12  in accordance with a third embodiment of the subject invention particularly suitable for use with a turbocharged ICE. The ICE/water source system  12  comprises an ICE assembly  16  and a water source assembly  100 . The ICE assembly  16  further comprises an ICE  20 , an exhaust gas turbocharger  56  having a turbine  52  and a turbo-compressor  68  operatively connected by a mechanical link  98 , a high-pressure exhaust duct  46 ′, a low-pressure exhaust duct  46 ″, a low pressure intake duct  32 ′, and a high-pressure intake duct  32 ″. The high-pressure (inlet) port of turbine  52  is fluidly connected to the exhaust passage  24  by means of the high-pressure exhaust duct  46 ′. The low-pressure (discharge) port of turbine  52  is fluidly connected to the atmosphere by means of the low-pressure exhaust duct  46 ″. The inlet (low pressure) port of turbo-compressor  68  is fluidly connected to a source of intake air by means of the low-pressure intake duct  32 ′. The discharge port of turbo-compressor  68  is fluidly connected to the intake passage  22  by means of the high-pressure intake duct  32 ″. The water source assembly  100  may be of the same design and construction as the water source assembly  100  practiced with the first embodiment of the subject invention and shown in  FIG. 3 .  
         [0045]     During normal operation of the ICE/water source system  12 , intake air stream  44 ′ flows through the low-pressure intake duct  32 ′ into the turbo-compressor  68  where it is compressed and fed as a stream  44 ″ through the high-pressure intake duct  32 ″ and the intake passage  22  into the combustion chamber  34  of ICE  20 . Furthermore, hydrocarbon-based fuel is supplied into the combustion chamber  34  and it is substantially combusted therein. Combustion products are exhausted from the combustion chamber  34  through the exhaust passage  24  into the high-pressure exhaust duct  46 ′ where they form an exhaust stream  92 ′. At typical operating conditions of the ICE system  15 , the pressure PE in the high-pressure exhaust duct  46 ′ may be much higher than the ambient atmospheric pressure, and the pressure pi in the low-pressure intake duct  32 ′ may be substantially lower than the ambient atmospheric pressure. A large portion of exhaust stream  92 ′ may flow through the exhaust duct upstream portion onto the inlet (high pressure) port of the turbine  52  where it may be used to operate the turbine. The pressure and temperature of the exhaust stream  92 ′ may be generally reduced inside the turbine thereby producing an exhaust stream  92 ″ at reduced pressure and temperature which flows through the low-pressure exhaust duct  46 ″. Water source  100  operates in a similar manner as the water source  100  used in the first embodiment except that the stream  142  may be now provided at a substantially higher pressure. As a result, the vortex tube  120  may now operate at a pressure ratio PE/PI substantially higher than 1.4 and thus may deliver improved cooling power. Preferably, process stream  138  flowing in line  118  is provided to the low-pressure intake duct  32 ′ as shown in  FIG. 5 . Alternatively, line  118  may feed the stream  138  to the low-pressure exhaust duct  46 ″, or to ambient atmosphere, or other suitable location.  
         [0046]     While only selected embodiments have been chosen to illustrate the present invention, it will be apparent to those skilled in the art from this disclosure that various changes and modifications can be made herein without departing from the scope of the present invention as defined in the appended claims. Furthermore, the foregoing description of the embodiments according to the present invention are provided for illustration only, and not for the purpose of limiting the present invention as defined by the appended claims and their equivalents. Thus, the scope of the present invention is not limited to the disclosed embodiments. In particular, the use of the subject invention is not limited automotive applications. For example, the subject invention may be used also in marine applications to generate fresh water.  
         [0047]     The terms of degree such as “substantially”, “about” and “approximately” as used herein mean a reasonable amount of deviation of the modified term such that the end result is not significantly changed. For example, these terms can be construed as including a deviation of at least ±5% of the modified term if this deviation would not negate the meaning of the word it modifies.  
         [0048]     Moreover, terms that are expressed as “means-plus function” in the claims should include any structure that can be utilized to carry out the function of that part of the present invention. In addition, the term “configured” as used herein to describe a component, section or part of a device includes hardware and/or software that is constructed and/or programmed to carry out the desired function.  
         [0049]     The term “intake air” used in this application should be given an broad interpretation. Thus, intake air is essentially a mixture of nitrogen, carbon dioxide, water vapor, oxygen, and inert gases, and it may also include ICE fuel vapor, nitrogen oxides, and hydrocarbons.  
         [0050]     The term “exhaust gases” used in this application should be given an broad interpretation. Thus, exhaust gases may contain nitrogen, carbon dioxide, water vapor, oxygen, gases, ICE fuel vapor, nitrogen oxides, and hydrocarbons.  
         [0051]     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” and “includes” and/or “including” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.  
         [0052]     The terms of degree such as “substantially”, “about” and “approximately” as used herein mean a reasonable amount of deviation of the modified term such that the end result is not significantly changed. For example, these terms can be construed as including a deviation of at least ±5% of the modified term if this deviation would not negate the meaning of the word it modifies.  
         [0053]     The term “suitable”, as used herein, means having characteristics that are sufficient to produce a desired result. Suitability for the intended purpose can be determined by one of ordinary skill in the art using only routine experimentation.  
         [0054]     While only selected embodiments have been chosen to illustrate the present invention, it will be apparent to those skilled in the art from this disclosure that various changes and modifications can be made herein without departing from the scope of the present invention as defined in the appended claims. Furthermore, the foregoing description of the embodiments according to the present invention are provided for illustration only, and not for the purpose of limiting the present invention as defined by the appended claims and their equivalents. Thus, the scope of the present invention is not limited to the disclosed embodiments.