System and apparatus for reducing liquid water emissions in the exhaust of a hydrogen engine

Abstract

A system for reducing the volume of liquid water emitted from an exhaust pipe of a hydrogen-fueled engine is described. A vaporizer unit has a main body portion, a spraying assembly and a vapor port. The main body portion surrounds at least a portion of an exhaust manifold of the engine. The vapor port couples the vaporizer unit to the exhaust pipe of the engine via a vapor pipe. The spraying assembly is configured to spray liquid water over at least a portion of the exhaust manifold. The apparatus also includes a liquid-vapor separator placed inline in the exhaust pipe of the engine, and a sump coupled to the exhaust pipe. The sump collects liquid water recovered by the liquid-vapor separator. Finally, the apparatus includes a pump coupled to the sump and to the spraying assembly and configured to provide the collected liquid water to the vaporizer unit.

Description

BACKGROUND

This following disclosure relates to improvements in the field of engines. In particular, this disclosure relates to an improved system and apparatus for reducing liquid water emissions from a hydrogen engine.

In recent years, there has been a keen interest in finding and exploiting alternative energy sources, particularly for vehicles such as busses, cars, trains and heavy equipment that are used by public entities. Such pursuits have resulted in a number of advances in vehicle engine design being brought to market over the last few years, including for example, the direct-injection diesel engine. One advance in engine design is the introduction of hydrogen-fueled engines. A hydrogen-fueled engine uses elemental hydrogen of easily obtained industrial purity as a fuel in an internal combustion engine. One example of a hydrogen engine is a hydrogen-conversion engine modification, which converts an engine designed to burn petroleum-based fuels to allow the engine to use hydrogen as a fuel.

Hydrogen fueled engines are of particular interest due to their inherently clean and low exhaust emissions. In particular, a hydrogen engine produces water, water vapor, and, in some instances, very small proportions of nitrogen oxides as by-products. Furthermore, a hydrogen engine produces essentially no carbon-based by-products at all, such as carbon monoxide and carbon dioxide. Therefore many hydrogen engines qualify as “zero emission” under certain governmental standards.

However, one problem with the emissions of a hydrogen engine is the occurrence of liquid water in the exhaust pipe of a vehicle. Water vapor emitted from a hydrogen engine, particularly in a hydrogen-conversion, can easily condense in the exhaust line of the engine and cause a number of problems. In particular, if excess fluid water is allowed to accrete in an exhaust line, it may rust internal surfaces and components. It is also undesirable to have liquid water emitted directly from a tailpipe as an effluent, as many vehicles, and also the attendant street infrastructure for the vehicles, are not designed to accommodate a steady flow of such effluent. Further, the cumulative effect of depositing significant amounts of liquid water on a roadway may result in an unsafe roadway conditions, such as reduced driver visibility due to water spraying off of vehicle tires, reduced roadway contact due to wet pavement, or if the water were to freeze. These adverse roadway conditions can worsen in heavily populated areas and create or contribute to multi-vehicle accidents. It is therefore desirable to provide advancements to the art that overcome these and other disadvantages.

SUMMARY

According to an embodiment described herein, an apparatus for reducing the volume of liquid water emitted from an exhaust pipe of a hydrogen-fueled engine is provided. The apparatus includes a vaporizer unit comprising a main body portion, a spraying assembly and a vapor port portion. The main body portion (or “housing”) surrounds at least a portion of an exhaust manifold of the engine. Furthermore, the main body portion is defined by an inner surface and an outer surface. The inner surface is defined in part by at least a portion of the exhaust manifold and the vapor port portion is defined by an opening in the vaporizer unit that is coupled to the exhaust pipe via a vapor pipe. As described herein, the spraying assembly comprises at least one spray nozzle supported by the main body portion and configured to spray liquid water over at least a portion of the exhaust manifold. The apparatus also includes a liquid-vapor separator placed inline in the exhaust pipe of the engine, and a sump coupled to the exhaust pipe. As described herein, the sump is configured to collect liquid water recovered by the liquid-vapor separator. Finally, the apparatus includes a pump coupled to the sump and to the spraying assembly and configured to provide the collected liquid water to the vaporizer unit. In one embodiment, the apparatus can further include insulation, such as sprayed-on insulation, on the outside of the entire apparatus to further reduce heat loss and lessen the amount of liquid water resulting from the cooling of the exhaust vapor.

According to another embodiment, a system for reducing the volume of liquid water emitted from the tailpipe of a hydrogen fueled engine includes means for collecting liquid water that condenses in the tailpipe from exhaust gasses emitted by the engine. The system also includes means for vaporizing the liquid water using waste heat from the engine. Finally, the system includes means for returning the vaporized collected water to the atmosphere via the tailpipe.

According to still another embodiment, a method for reducing the volume of liquid water ultimately emitted from an exhaust pipe of a hydrogen fueled engine is described. The method includes collecting liquid water from the exhaust pipe, vaporizing the water using waste heat from the engine, and then emitting the vaporized water to the atmosphere via the exhaust pipe.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevation view depicting an apparatus for reducing the volume of liquid water emitted from an exhaust pipe of a hydrogen-fueled engine in accordance with one embodiment.

FIG. 2 is cross-sectional view of the apparatus of FIG. 1 as taken along 2-2 of FIG. 1.

FIG. 3 is another cross-sectional view of the apparatus of FIG. 1, as taken along 3-3 of FIG. 1.

FIG. 4 is another cross-sectional view of the apparatus of FIG. 1, as taken along 4-4 of FIG. 1.

FIG. 5 is fragmented sectional view of the apparatus of FIG. 4 as taken along 5-5 of FIG. 4.

FIG. 6 is a flow diagram illustrating a method, according to another embodiment.

FIG. 7 is a side elevation view depicting an apparatus for reducing the volume of liquid water emitted from an exhaust pipe of a hydrogen-fueled engine in accordance with a further embodiment.

FIG. 8 is a side elevation view depicting an apparatus for reducing the volume of liquid water emitted from an exhaust pipe of a hydrogen-fueled engine in accordance with yet another embodiment.

DETAILED DESCRIPTION

FIG. 1 is a plan view depicting an example of a system and apparatus for reducing the volume of liquid water emitted from an exhaust pipe of a hydrogen-fueled engine, in accordance with one embodiment. FIG. 1 depicts a liquid water reducing system 100 that will be discussed in detail in the following description of FIGS. 1-5. Generally, water reducing system 100 includes components that provide means for collecting liquid water that condenses in the tailpipe from exhaust gasses emitted by the engine, components that provide means for vaporizing the liquid water using waste heat from the engine, and components that provide means for returning the vaporized collected water to the atmosphere via the tailpipe. Various components of liquid water reducing system 100 are depicted in the Figures and the following description with reference to a hydrogen fueled engine. The operation of such engines is well known in the art, and is not the subject of this discussion, and therefore will not be further discussed. Further, it will be appreciated that the system described herein can be used with other engines wherein liquid effluent is undesirable.

Turning now to FIG. 1, the water reducing system 100 is depicted including a vaporizer unit 170 that provides means for vaporizing liquid water using waste heat from the engine and which comprises a main body portion 110, a spraying assembly 111 and a vapor port 112. In one embodiment, the main body portion 110 of the vaporizer unit 170 is further defined by a front face 175, and four side faces 171, 172, 173, 174 respectively. As shown in FIG. 1, the main body portion 110 surrounds at least a portion of an exhaust manifold 113 of the engine 201, depicted in FIG. 3. Means for returning the vaporized collected water to the atmosphere via the tailpipe are also provided. For example, FIG. 1 depicts the main body portion 110 of the vaporizer unit 170 coupled to an exhaust pipe 130 via a vapor port 112.

Means for collecting liquid water that condenses in the tailpipe from exhaust gasses emitted by the engine are also depicted in FIG. 1. One example of liquid collection means includes a liquid-vapor separator 150, as is shown placed inline with the engines exhaust pipe 130. Another example of liquid collection means includes a sump (or “liquid collector”) 155 configured to collect liquid water recovered by the liquid-vapor separator 150, and is depicted in FIG. 1 as being coupled to the liquid-vapor separator 150 and to the exhaust pipe 130. Yet another example of liquid collection means can include a pump 160 configured to provide the collected liquid water to the vaporizer unit 170. In FIG. 1 the pump 160 is shown coupled to the sump 155 via a drain 156. Pump 160 can be any pump suitable for moving water from the sump 155 to the spraying assembly 111, such as for example a vibratory pump or a rotary vane pump, as will be known to the skilled practitioner. In one embodiment (not shown), the liquid water reducing system 100 includes a feedback control system for monitoring the temperature of the manifold 113 and the water level in the sump 155 and for controlling the pump and spraying assembly so that the liquid water reducing system 100 is operational only when predetermined operational conditions are detected, such as for example, a baseline manifold 113 temperature and adequate water level for safe pump 160 operation.

Other means for vaporizing liquid water using waste heat from the engine are depicted in FIG. 1. For example, one component of vaporizing means can include a liquid return line 120, as is shown in FIG. 1, that couples the pump 160 to the spray assembly 111 of the vaporizer unit 170. Generally, the spray assembly 111 can include any components for spraying liquid, such as for example spray nozzles, spray nozzle mounting hardware, and any other components that allow the spraying of liquid water or other liquids. In one embodiment, the liquid return line 120 is at least partially disposed proximate to a section of the exhaust pipe 130 that is between the pump 160 and the exhaust manifold 113. In one embodiment the liquid return line 120 is covered with a heat-retaining insulation 121 to allow recovered liquid to be pre-heated prior to providing the recovered liquid to the vaporizer unit 170. In another embodiment, the heat-retaining insulation material 121 comprises one or more materials such as, but not limited to, graphite composite, fiberglass, aluminized polyester, aluminum, ceramic, and the like. In yet another embodiment, all or a portion of the exhaust pipe 130 can be covered with a heat-retaining insulation 231 to increase the transfer of heat to the liquid return line 120 and reduce condensation in the exhaust pipe.

In one embodiment, the liquid-vapor separator 150 includes a housing 153 that defines an enclosed space 154 interior to the separator 150 that can house a catalyst or other medium 151 to facilitate a separation of liquid from vapor. In another embodiment, the medium 151 in the liquid-vapor separator is a material having a large surface area that enhances the condensation surface area of the interior space 154 of liquid-vapor separator 150, without unduly restricting the flow of vapor. Surface area enhancing materials used for the medium 151 can include, but are not limited to, plastic beads, glass beads, ceramic beads, metal wool, fiberglass wool, and expanded metal.

Other means for collecting liquid water that condenses in the tailpipe from exhaust gasses emitted by the engine are also depicted in FIG. 1. As shown in FIG. 1, the liquid water reducing system 100 also includes water collection means such as a drain channel 135 disposed between the liquid-vapor separator 150 and an ambient exhaust point 131 of the exhaust pipe 130. In one embodiment, the drain channel 135 is sloped towards, and drained into, the sump 155. One embodiment further comprises a fluid deflector 157 that affixes to the exhaust pipe 130 and is directed into the sump 155, such that water collected in the sump 155 is prevented from re-entering the exhaust pipe 130 from the sump 155 as exhaust gasses pass through the liquid-vapor separator 150. In still another embodiment, a filter screen 132 is positioned above the drain channel 135 to allow fluid to drain from the exhaust pipe 130 to the drain channel. The filter screen 132 can also assist in preventing liquid from re-entering the exhaust pipe 130. In order to further illustrate the features of the liquid water reducing system 100 shown in FIG. 1, alternative views of the various embodiments shown in FIG. 1 will now be discussed in FIGS. 2-5.

FIG. 2 is cross-sectional view of the apparatus of FIG. 1 as taken along 2-2 of FIG. 1. As discussed in the description of FIG. 1 above, the liquid water reducing system 100 includes a vaporizer unit 170. In the example depicted in FIG. 2, the front face 175 of the main body portion 110 is substantially rectangular and defined by one or more openings 221 for one or more output pipes 230 of the exhaust manifold 113. The four side faces of the main body portion 110 (shown in FIG. 1 as 171, 172, 173, 174) extend generally perpendicularly from an edge of each of the four sides of the front face 175 to form an open bottomed box having an interior space 220.

In the example depicted in FIG. 3, the main body portion 110 is positioned on the exhaust manifold 113 such that each of the side faces (e.g., 171, 172, 173, 174 of FIG. 1) enclose at least a portion of the exhaust manifold, and the one or more output pipes 230 traverse the interior space 220 of the main body portion 110 and exit the one or more openings 221 at the front face 175 of the main body portion 110. Further, in the example depicted in FIGS. 1 and 3, the vaporizer unit 170 is affixed to the housing 110 by mechanical coupling, such a weld, a bolt, a rivet, etc. The main body portion 110 can be manufactured from a material such as, for example, plastic, graphite composite, aluminum, steel or ceramic. Further, output pipes 230 can be sealed at the openings 221 in the housing (main body portion 110) using a sealant such as silicone or the like. In the example depicted in FIG. 2, the vapor port 112 joins the main body portion 110 of the vaporizer unit 170 to the exhaust pipe 130 at a point below an expansion section 240 of the exhaust manifold 113. In other embodiments however, the vapor port 112 can be joined to the exhaust manifold 113 or the exhaust pipe in any suitable location. The liquid return line 120 is also shown in FIG. 2 affixed to the exhaust pipe 130 along a lower portion of the exhaust pipe. It should be appreciated, however, that the liquid return line 120 can be positioned in any suitable manner along the length of the exhaust pipe 130, and is not limited to the embodiment illustrated in FIG. 2. As shown in FIG. 2, a heat retaining insulation material 231 can surround a portion of the exhaust pipe 130. In this example, the heat retaining insulation 231 can increase the transfer of heat from the exhaust pipe 130 to the liquid return line 120.

FIG. 3 is another cross-sectional view apparatus of FIGS. 1 and 2 as taken along 3-3 of FIG. 1. As shown in FIG. 3, the main body portion 110 includes an inner surface 315 and an outer surface 316. In the example shown, the inner surface 315 is defined in part by at least a portion of the exhaust manifold 113. Further, in the example shown, the vapor port portion 112 (“vapor pipe”) is defined by an opening 313 in the vaporizer unit 170 that couples the vapor port 112 to the exhaust pipe 130.

As further illustrated in FIG. 3, the spraying assembly (111 of FIG. 1) comprises one or more spray nozzles (111a and 111b) that are supported by the main body portion 110 and configured to spray liquid water into the interior volume 220 of the main body portion 110, and in particular over at least a portion of the exhaust manifold 113 (and more particularly, over at least a portion of the output pipes 230). Generally, the spray nozzles (e.g., 111a and 111b) can include threaded mounting hardware and seals and the like that allow them to be mechanically coupled to the main body portion 110 with a water-tight seal. As depicted in the example shown in FIG. 3, the spray nozzles 111a and 111b are coupled to corresponding liquid return lines 120a and 120b, respectively, that are fed by a main liquid return line (e.g., 120 of FIGS. 1 and 2). While FIGS. 1 and 3 depict the spray nozzles 111a, 111 b as being positioned at only the right side 172 of the housing 110, it will be appreciated that the spray nozzles can be positioned in other locations as well. For example, spray nozzles can be positioned at any or all (or any combination thereof) of the sides 171-175 of the housing 110 (and including the back side of the housing 110 opposite the front face 175).

The spray nozzles 111a, 111 b are configured to generally atomize liquid (water, typically) from the liquid return line 120 and disperse the liquid over the output pipes 230. However, in one variation rather than atomizing the liquid, the liquid can be dripped directly onto the output pipes 230. In general, various spray nozzles and the techniques for implementing them will be known to the skilled practitioner and therefore will not be further discussed.

In one variation, the inner surface 315 of the main body portion 110 can be coated with a sealant (not shown) that provides a water-tight seal over the entire inner surface 315 of the main body portion. The sealant can be a high-temperature silicone, for example.

As illustrated in FIG. 3, the exhaust manifold 113 can comprises a plurality of separate outlet pipes 230 and a header (e.g., 240 of FIG. 2) that couples the plurality of outlet pipes 230 to the exhaust pipe 130. In another embodiment (not shown) a valve assembly placed in the opening 313 of the vapor port 112 can be configured to reduce the amount of back-flow exhaust gasses from the exhaust pipe 130 that can enter the main body portion 110 through the vapor port 112.

In still another variation, the main body portion 110 can include a flange 314 for mechanically coupling the main body portion 110 to the engine 201. In one embodiment, the flange 314 includes a plurality of through-holes for mechanical couplers, such as rivets, bolts, etc., for coupling the housing to the engine 201. Further, sealing agents, such as silicone and the like, can be used to seal the main body portion 110 to the engine 201. FIG. 3 also depicts a heat retaining insulation material 231 that can surround all, or a portion of, the exhaust pipe 130, as well as all, or a portion of, the output pipes 230 exterior of the housing 110. Although not depicted in FIG. 1, the insulation material 231 can also surround all, or a portion of, the liquid-vapor separator 150. In the illustrated example, the heat retaining insulation 231 can increase the transfer of heat from the exhaust pipe 130 to the liquid return line 120, and further retain existing heat from the output pipes 230.

In the example depicted in FIGS. 1-3, the main body portion (“housing”) 110 of the system 100 is depicted as being generally in the shape of a rectangular box, with the output pipes 230 exiting the housing 110 at the front face 175. However, it will be appreciated that the housing 110 can be formed in other shapes in cross section (top section, side section, and/or end section), such as elliptical, spherical, and other polygonal shapes. Further, it will be appreciated that the output pipes 230 can exit the housing 110 at openings 221 at locations other than the front face 175. For example, the output pipes 230 can exit the housing 110 at the bottom side 173, the left side 174, the right side 172, the top side 171, the back side (not numbered, but opposite to the front face 175), or combinations thereof. Moreover, while FIGS. 1-3 depict the output pipes 230 as each exiting the housing 110 at distinct openings 221, in another example the header 240 that joins the output pipes 230 together into the exhaust pipe 130 can also be enclosed within the housing 110, thus reducing the number of openings 221 within the housing 110. Additionally, while openings 221 can be sealed against output pipes 230, in another example there can be a gap between the openings and the output pipes 230. In fact, rather than exhaust vapor from the interior 220 of the housing 110 back into the exhaust pipe 130 via vapor port 112, in another embodiment some (or all) of the vapor within the interior 220 of the housing 110 can be exhausted directly to the ambient atmosphere through outlet 313.

In one variation depicted in FIG. 8, rather than the exhaust vapor (from within the housing 110) being reintroduced into the exhaust pipe 130 via vapor port 112, the vapor port 193 can attach to a separate pipe which directs the vapor exiting the body portion 110 directly to the liquid-vapor separator 150. This separate pipe can encase the exhaust pipe 130 as depicted, can be placed adjacent the exhaust pipe (not shown), or can be routed within the exhaust pipe (also not shown). Further, as indicated above, vapor exiting the body portion 110 can be routed directly to the ambient atmosphere as indicated in FIG. 7 by separate pipe 191. Techniques for implementing these variations will be readily apparent to the skilled practitioner in light of the present disclosure, and therefore further elaboration is not required.

In general, the housing 110 comprises a jacket that encloses at least a portion of the output pipes 230. The spray assembly 110 sprays liquid (typically liquid water) into the interior 220 of the housing 110 and onto the portion of the output pipes 230 enclosed by the housing 110. Heat from the output pipes 230 causes at least a portion of the liquid water sprayed into the interior 220 of the housing 110 to vaporize within the interior of the housing, and the vapor within the interior of the housing is then exhausted back into the exhaust pipe 130 or to another location (such as to the ambient atmosphere).

FIG. 4 is another cross-sectional view of the apparatus of FIG. 1, as taken along 4-4 of FIG. 1, illustrating additional features than can be provided. As depicted in FIG. 4, the exhaust pipe can 130 include a drain channel 135 that is mechanically coupled to the exhaust pipe 130. The drain channel 135 can be composed of a material such as, but not limited to, stainless steel, aluminum alloy, plastic, resin, and graphite composite. As shown in the example depicted in FIG. 4, the drain channel 135 is coupled to the exhaust pipe 130 with connectors (421a and 421b) such as screws, rivets, bolts, etc. The drain channel 135 can also be affixed to the exhaust pipe 130 with a weld, an epoxy or another mechanical coupling technique, or it can be part of an integral extrusion that includes the exhaust pipe 130 and the drain channel 135. A screen 132 can be provided between the exhaust pipe 130 and the drain channel 135. The screen can be selected from any conventional heat tolerant screen material that allows water to pass through to the drain channel 135, such as metal screen, carbon composite screen and high-temperature plastic screen, for example.

FIG. 5 is fragmented sectional view of the apparatus of FIG. 4, as taken along 5-5 of FIG. 4. As shown in FIG. 5, the screen 132 separates the exhaust pipe 130 from the drain channel 135. Fasteners 421a and 421b are also illustrated in FIG. 5, in one exemplary configuration for attaching the drain channel 135 and screen 132 to the exhaust pipe 130.

Now that several exemplary embodiments of the components of the liquid water reducing system have been illustrated, an application of the components to reduce the occurrence of liquid water in the exhaust line of a hydrogen-powered engine will be discussed.

FIG. 6 is a flow diagram illustrating a method, according to an embodiment. FIG. 6 illustrates a method 600 for method for reducing the volume of liquid water ultimately emitted from an exhaust pipe of a hydrogen fueled engine. In one embodiment, method 600 is implemented with components of the exemplary system and apparatus according to one or more of the embodiments described with reference to FIGS. 1-5. Method 600 begins in step 610. Various steps of the method 600 are described with respect to a method 600 for reducing the volume of liquid ultimately emitted from an exhaust pipe of an engine. In some implementations, certain steps of method 600 can be combined, performed simultaneously or in a different order, without deviating from the objective of method 600 or without producing different results.

In step 610, liquid (typically, but not limited to, water) is collected from the exhaust pipe of an engine (which can be, for example, a hydrogen fueled engine). The liquid (water, in the present example) is collected at any time that liquid is accumulating in the exhaust pipe of the engine. In general, the liquid water is collected by the force of gravity as the water flows from various part of the liquid water reducing system 100 into a sump (e.g., item 155, FIG. 1). In one embodiment, the water is collected as water condensing in the exhaust pipe 130 (FIG. 1) is directed to the sump (155) via a liquid deflector 157. In another embodiment, water is collected in the sump (155) via a water-vapor separator 150 that separates liquid water from vapor, and can also cause water vapor close to the liquid state to condense into liquid. In one embodiment, the collected liquid water can be also be drained from the sump 155 to a pump 160 (either directly, or via a drain line 156).

In step 620 (FIG. 6), the collected liquid water is vaporized using waste heat from the engine 201 (FIG. 1). The collected liquid water is provided at any time that the liquid reducing system (e.g., system 100, FIG. 1), and in particular the pump (e.g., 160, FIG. 1) and the vaporizer unit (e.g., 170, FIG. 1) are operational. In one embodiment, a feedback control system can control the operation of the vaporizing so that the liquid water reducing system (e.g., 100, FIG. 1) only becomes operational when the engine manifold (e.g., 113, FIG. 1) is heated to a predetermined temperature and/or there is a safe level of water in the sump 155 with which to operate pump 160. In another embodiment, the step of vaporizing further includes the steps of providing the collected water from the pump 160 to the vaporizer unit 170 via a liquid return line (e.g., line 120, FIG. 1) and then spraying the collected liquid over the exhaust manifold (e.g., 113, FIG. 1). In another embodiment, the collected water is provided to the vaporizer unit 170 intermittently, based on a predetermined amount of collected water in the sump 155.

In one embodiment, the vaporizer unit 170 includes at least one spray nozzle disposed within a jacket (e.g., main body portion 110, FIG. 1) that is formed at least partially around an exhaust manifold (113, FIG. 1) of the engine. In another embodiment, the collected water is pre-heated prior to spraying by thermally coupling a liquid return line (e.g., 120, FIG. 1) to at least a portion of the exhaust pipe 130 of the engine. In another embodiment, the collected water is sprayed over the manifold with the spray nozzles and the sprayed pre-heated water contained within the water-tight jacket is vaporized by the heat of the exhaust manifold. In yet another embodiment, the collected water is filtered and/or strained prior to the pumping it to the vaporizer unit 170 to prevent clogs in the spray nozzles, and to preserve pump life.

In step 630 (FIG. 6), the vaporized water is emitted to the atmosphere via the exhaust pipe (e.g., via tailpipe 131, FIG. 1). The vaporized water is emitted at any time that the vaporized water is produced, as in step 620. In one embodiment, the vaporized water is emitted to the atmosphere via the exhaust pipe 130 by directing the vaporized water to a vapor port 112 that is in fluid communication with the exhaust pipe 130. In another embodiment, the exhaust pipe 130 is insulated with a heat-retaining insulation to reduce the amount of water vapor that re-condenses in the exhaust pipe. In yet another embodiment, a valve assembly placed between the exhaust pipe 130 and the vapor port 112 reduces exhaust gas back-flow from the exhaust pipe 130 into the main body portion 110 of the vaporizer unit 170. In another embodiment, exhaust gasses from the exhaust pipe 130 are directed into the main body portion 110 with a valve assembly to increase the vaporization rate of sprayed recovered water prior to emission into the exhaust port 112.

A further embodiment provides for an apparatus including a jacket (e.g., jacket or housing 110, FIGS. 1-3) configured to cover at least a portion of an exhaust manifold (e.g., item 113, FIGS. 1-3) of an engine (e.g., item 201, FIG. 3). The apparatus of this embodiment further includes a liquid collector (e.g., sump 155 of FIG. 1) configured to collect liquids within an exhaust pipe (e.g., item 130 of FIGS. 1-5) connected to the exhaust manifold, and a pump (e.g., item 160, FIG. 1) configured to pump liquids from the liquid collector to the jacket. The apparatus also includes a spray assembly (e.g., 111, FIG. 1) configured to spray liquids from the pump over the portion of the exhaust manifold covered by the jacket.

Yet an additional embodiment provides for an apparatus including an engine (e.g., item 201, FIG. 3), an exhaust manifold (e.g., item 113, FIGS. 1-3) in fluid communication with the engine, and an exhaust pipe (e.g., item 130, FIGS. 1-3) in fluid communication with the manifold. The apparatus further includes a jacket (e.g., jacket or housing 110, FIGS. 1-3) configured to cover at least a portion of the exhaust manifold (e.g., item 113, FIGS. 1-3) of then engine (e.g., item 201, FIG. 3). The apparatus of this embodiment further includes a liquid collector (e.g., sump 155 of FIG. 1) configured to collect liquids within an exhaust pipe (e.g., item 130 of FIGS. 1-5) connected to the exhaust manifold, and a pump (e.g., item 160, FIG. 1) configured to pump liquids from the liquid collector to the jacket. The apparatus also includes a spray assembly (e.g., 111, FIG. 1) configured to spray liquids from the pump over the portion of the exhaust manifold covered by the jacket.

A further embodiment provides for a vehicle having an engine (e.g., item 201, FIG. 3), an exhaust manifold (e.g., item 113, FIGS. 1-3) in fluid communication with the engine, and an exhaust pipe (e.g., item 130, FIGS. 1-3) in fluid communication with the manifold. The apparatus further includes a jacket (e.g., jacket or housing 110, FIGS. 1-3) configured to cover at least a portion of the exhaust manifold (e.g., item 113, FIGS. 1-3) of then engine (e.g., item 201, FIG. 3). The apparatus of this embodiment further includes a liquid collector (e.g., sump 155 of FIG. 1) configured to collect liquids within an exhaust pipe (e.g., item 130 of FIGS. 1-5) connected to the exhaust manifold, and a pump (e.g., item 160, FIG. 1) configured to pump liquids from the liquid collector to the jacket. The apparatus also includes a spray assembly (e.g., 111, FIG. 1) configured to spray liquids from the pump over the portion of the exhaust manifold covered by the jacket.

It is understood that the methods and apparatus disclosed herein can be embodied in other specific forms not described that do not depart from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive, the scope of the embodiments being defined by the appended claims and equivalents thereof.

Claims

1. A method to reduce the volume of liquid water ultimately emitted from an exhaust pipe of a hydrogen fueled engine comprising:

collecting liquid water from the exhaust pipe;

vaporizing the liquid water using waste heat from the engine; and

emitting the vaporized liquid water to the atmosphere.

2. The method of claim 1 further comprising pumping the collected liquid water to a vaporizer unit wherein the vaporizing is performed.

3. The method of claim 1 wherein the vaporized liquid water is emitted to the atmosphere via the exhaust pipe.

4. The method of claim 1 wherein the vaporized liquid water is emitted to the atmosphere via a separate pipe.

5. The method of claim 2 further comprising filtering the collected liquid water prior to the pumping.

6. The method of claim 1 wherein vaporizing the liquid water using waste heat from the engine comprises:

providing the collected liquid water to a vaporizer unit, the vaporizer unit comprising at least one spray nozzle disposed within a jacket that is formed at least partially around an exhaust manifold of the engine; and

spraying the collected liquid over the exhaust manifold with the spray nozzles, wherein the sprayed liquid water is contained within the jacket.

7. The method of claim 6 further comprising pre-heating the collected liquid water with recovered waste heat from at least a portion of the exhaust pipe.

8. The method of claim 1 wherein emitting the vaporized liquid water to the atmosphere via the exhaust pipe comprises directing the vaporized liquid water to a vapor port that is in fluid communication with the exhaust pipe.

9. The method of claim 6 further comprising making the jacket liquid-tight around the exhaust manifold of the engine.

10. An apparatus to reduce the volume of liquid water emitted from an exhaust pipe of a hydrogen-fueled engine, comprising:

a vaporizer unit comprising a main body portion, a spraying assembly and a vapor port portion, and wherein: the main body portion surrounds at least a portion of an exhaust manifold of the engine; the main body portion is defined by an inner surface and an outer surface; the inner surface is defined in part by at least a portion of the exhaust manifold; the vapor port portion is defined by an opening in the vaporizer unit; the spraying assembly comprises at least one spray nozzle supported by the main body portion and configured to spray liquid water over at least a portion of the exhaust manifold;

a sump coupled to the exhaust pipe wherein the sump is configured to collect liquid water recovered from the exhaust pipe; and

a pump coupled to the sump and to the spraying assembly and configured to provide the collected liquid water to the vaporizer unit.

11. The apparatus of claim 10 further comprising a liquid-vapor separator placed inline in the exhaust pipe of the engine, and wherein the sump is configured to collect liquid water from the liquid-vapor separator.

12. The apparatus of claim 10 further comprising a liquid return line that couples the pump to the vaporizer unit.

13. The apparatus of claim 12 wherein the liquid return line is at least partially disposed proximate to a portion of the exhaust pipe that is between the pump and the exhaust manifold.

14. The apparatus of claim 13 wherein the liquid return line is covered with a heat-retaining insulation.

15. The apparatus of claim 14 wherein the heat retaining insulation material is selected from the group consisting of graphite composite, fiberglass, mylar, aluminum and ceramic.

16. The apparatus of claim 10 wherein at least a portion of the exhaust pipe is covered with a heat-retaining insulation to increase the transfer of heat to the liquid return line.

17. The apparatus of claim 12 wherein the liquid-vapor separator comprises a separator housing that defines an enclosed space interior to the separator housing, and wherein the enclosed space includes a medium to cause a separation of liquid water from water vapor.

18. The apparatus of claim 17 wherein the medium is a surface area enhancing material selected from the group consisting of plastic beads, glass beads, ceramic beads, metal wool, fiberglass wool, and expanded metal.

19. The apparatus of claim 10 wherein:

the exhaust manifold comprises a plurality of separate outlet pipes and a header that is connected to the plurality of outlet pipes, and wherein the exhaust pipe is connected to the header;

the main body portion is further defined by a front face, and four side faces, and wherein: the front face is substantially rectangular and defined by one or more openings for the one or more output pipes; the four side faces extend generally perpendicularly from an edge of each of the four sides of the front face to define an open sided box defining an interior space; and

wherein the main body portion is positioned on the exhaust manifold such that each of the side faces are affixed to the exhaust manifold, and the one or more output pipes traverse the interior space of the main body portion and exit the one or more openings on the front face of the main body portion.

20. The apparatus of claim 10 wherein the main body portion is composed of a material selected from the group consisting of plastic, graphite composite, aluminum, steel and ceramic.

21. The apparatus of claim 10 further comprising a drain channel disposed in the exhaust pipe between the liquid-vapor separator and an ambient exhaust point of the exhaust pipe, and wherein the drain channel is drained into the sump.

22. The apparatus of claim 21 further comprising a filter screen positioned between the exhaust pipe and the drain channel.

23. The apparatus of claim 10 further comprising a fluid deflector disposed within the exhaust pipe to prevent water from the sump from re-entering the exhaust pipe as exhaust gasses flow through the liquid-vapor separator.

24. The apparatus of claim 10 wherein the spraying assembly comprises two nozzles supported by the main body portion and configured to spray liquid water over at least a portion of the exhaust manifold.

25. The apparatus of claim 10 wherein the inner surface is coated with a sealant.

26. The apparatus of claim 25 wherein the sealant is a high temperature silicone.

27. The apparatus of claim 10 wherein the opening in the vaporizer unit is coupled to the exhaust pipe via a vapor pipe.

28. The apparatus of claim 10 wherein the opening in the vaporizer unit is vented directly to atmosphere outside of the body portion.

29. The apparatus of claim 10 wherein the opening in the vaporizer unit is vented to the liquid-vapor separator via a secondary pipe.

30. The apparatus of claim 29 wherein the secondary pipe encases the exhaust pipe.

31. A system to reduce the volume of liquid water emitted from the tailpipe of a hydrogen fueled engine, comprising:

means for collecting liquid water that condenses in the tailpipe from exhaust gasses emitted by the engine;

means for vaporizing the liquid water using waste heat from the engine; and

means for returning the vaporized collected water to the atmosphere via the tailpipe.

32. An apparatus comprising:

a jacket configured to cover at least a portion of an exhaust manifold of an engine;

a liquid collector configured to collect liquids within an exhaust pipe connected to the exhaust manifold;

a pump configured to pump liquids from the liquid collector to the jacket; and

a spray assembly configured to spray liquids from the pump over the portion of the exhaust manifold covered by the jacket.