JP2013508600A - Fuel vapor system for fuel economizer for internal combustion engine - Google Patents

Abstract

A fuel vaporizer for an internal combustion engine has a closed pressure chamber that is heated to define a volume and a liquid fuel supply system that is arranged to inject a liquid fuel spray. The closed pressure chamber is configured and arranged with respect to the heat transfer surface so as to form a mixing region between the at least one outlet and the heat transfer surface, in which the fuel spray is aforesaid. As it advances through its volume from its outlet, it has received heat from the heat transfer surface by moving on the heat transfer surface previously and is mixed with fuel vapor that has been recirculated and heated. Is heated and vaporized. The fuel vaporizer communicates with a steam outlet passage, through which the pressurized steam flows into a closed pressure chamber so as to be supplied to at least one combustion region. This heat conducting surface can be arranged to be heated by the coolant of the internal combustion engine circulating around the outside of the closed pressure chamber.

Description

  The present invention relates to a system that converts liquid fuel into fuel vapor to improve combustion in an internal combustion engine.

  The manner in which fuel is supplied to the engine has a significant impact on both fuel efficiency and exhaust emissions. In a piston engine with a carburetor, liquid gasoline is introduced into the center of the combustion air stream, after which the air / fuel mixture is branched and distributed to the engine cylinders. In a piston engine having a fuel injection device in a plurality of cylinders, pressurized liquid fuel is forced through a nozzle of the fuel injection device so as to inject a spray of liquid fuel particles. These sprays are injected into the mixture at the intake port of the cylinder or directly into the combustion zone. Incomplete combustion of fuel in these and other engines adversely affects fuel savings and produces harmful emissions.

  Over the past several decades, various proposals have been made for pre-vaporized fuel as a means for improving the fuel efficiency of internal combustion engines and reducing exhaust emissions.

  Cooke (US Pat. No. 5,746,188) and Shetley (US Pat. No. 6,758,194) describe several examples of fuel vaporizers using electric heating elements.

US Pat. No. 5,746,188 US Pat. No. 6,758,194

  Despite the above proposals, there is considerable room for improving fuel efficiency and reducing emissions.

  A fuel evaporation apparatus for an internal combustion engine includes a first closed chamber defining a first volume at least partially surrounded by a wall, and a heat transfer surface inside the first closed chamber. A second closed chamber, at least partially surrounding the first closed chamber and defining a second volume, a liquid fuel supply line and a fuel injection device, the fuel injection The apparatus is arranged to inject a magnified pattern of liquid fuel spray into the first volume under pressure from at least one orifice spaced from the heat transfer surface including. The thermal fluid system is configured to introduce a heated fluid into the second volume, transfer heat from the heated fluid through all of the first closed chamber, and is vaporized The fuel outlet is configured to move the vaporized fuel from the first closed chamber to a combustion fuel supply line that supplies fuel to at least one combustion region of the engine.

  In some embodiments, the heat transfer surface of the first closed chamber is the wall of the first closed chamber. Optionally, the heat transfer surface can be an increased surface area member that conducts heat with the walls of the supply stem.

  The vaporization system can also include an optimal pressure relief valve. The pressure relief valve is configured to open when the pressure inside the first closed chamber exceeds a predetermined threshold and move the vaporized fuel to the liquid fuel supply system. be able to. The first closed chamber may also include an upper end and a lower end, which may constitute a vaporized fuel outlet, at which the liquid fuel return may be configured.

  Some embodiments may provide a method of supplying fuel to at least one combustion region of an internal combustion engine. The method introduces a heated fluid into a volume that at least partially surrounds the vaporization chamber, transfers heat from the heated fluid to the vaporization chamber, and transfers fuel to the vaporization chamber via a liquid fuel supply line. Supplying and injecting substantially liquid fuel into the vaporization chamber at superatmospheric pressure, vaporizing the substantially liquid fuel in the vaporization chamber, and discharging the vaporized fuel from the vaporization chamber to the combustion chamber fuel supply line. .

  The method of the present invention further receives at the liquid fuel bypass valve a signal indicating that the vaporized fuel supplied from the vaporization chamber is insufficient for the fuel required in the combustion zone, and the liquid fuel bypass valve At least partially, and diverting the vaporization chamber by diverting the liquid fuel from the liquid fuel supply line to the combustion chamber fuel supply line. The method of the present invention can also include returning liquid fuel from the vaporization chamber to the liquid fuel supply line. Further, the method of the present invention can include opening the pressure relief valve when the pressure in the vaporization chamber exceeds a predetermined threshold.

  Some embodiments of the present invention may include a fuel vaporizer or fuel evaporator for an internal combustion engine. The fuel vaporizer includes a closed pressure chamber defining a volume, a heat conducting surface associated with the volume and arranged to be heated, and spaced from the heat conducting surface. A fuel supply device arranged to inject an enlarged pattern of liquid fuel spray into the volume from at least one orifice under superatmospheric pressure, the liquid fuel supply device comprising a fuel for vaporization For injection into at least one combustion zone of the internal combustion engine. The closed pressure chamber and liquid fuel supply line are configured and arranged with respect to the heat transfer surface so as to form a mixing region between the at least one outlet and the heat transfer surface, in which the fuel is The spray of the recalculated heated fuel vapor that has previously traveled over the heat conducting surface and receiving heat from the heat conducting surface as it advances from the outlet through the aforementioned volume. By mixing, it is substantially heated and vaporized. The fuel vaporizer is linked to the steam discharge passage so that the pressurized steam exits the closed pressure chamber via the steam outlet passage and is supplied to the at least one combustion zone. Can do. This heat conducting surface can be arranged to be at least partly heated by a coolant circulating outside the closed pressure chamber.

  Some embodiments may further include a second closed chamber. This second closed chamber at least partially surrounds said closed pressure chamber and defines a volume through which engine coolant circulates. Further, some embodiments may include an engine coolant inlet and an engine coolant outlet. In these embodiments, the engine coolant entering through the engine coolant inlet is at a higher temperature than the engine coolant exiting through the engine coolant outlet.

  Some embodiments may also include a flow control device associated with the outlet passage of the vaporizer described above. The flow control device includes at least one fuel vapor injector, and the at least one fuel vapor injector is directly in each at least one combustion zone configured to operate according to a respective requirement. Alternatively, or indirectly, the fuel vaporizer described above allows pressurized fuel vapor to flow to the engine while maintaining a substantially superatmospheric pressure within the volume where the vapor is generated. Configured and arranged as such. The fuel vaporizer described above can also include a liquid fuel return outlet.

  Details of design matters selected within the scope of the invention are set forth in the accompanying drawings and the description below.

FIG. 1 is a cross-sectional view of a fuel evaporation system for an internal combustion engine according to an exemplary embodiment of the present invention. FIG. 2 is a cross-sectional view of a fuel evaporation system for an internal combustion engine according to another exemplary embodiment of the present invention. FIG. 3 is a simplified schematic diagram of a fuel system including a fuel vaporizer according to an exemplary embodiment of the present invention. FIG. 4 is a simplified schematic diagram of the present invention for an internal combustion engine and fluid coolant system.

  The embodiments disclosed herein are merely illustrative in a characteristic manner for making and using the invention and should not be construed as limiting the scope of the invention.

  While the invention has been described in some detail, it should be noted that many variations in the details of the structure of the invention and the arrangement of its components are possible without departing from the spirit and scope of this disclosure. Should. The present invention should not be limited to the embodiments described herein for purposes of illustration.

  Several preferred embodiments of the present invention are described in FIGS. 1-4, where engine coolant is used to heat the vaporization chamber. In the vaporizer embodiment shown in FIG. 1, the vaporization chamber 900 is at least partially surrounded by a coolant chamber 905, thereby forming a coolant cavity 910.

  In known internal combustion engines that are cooled with a liquid, a liquid such as a coolant is delivered in a plurality of conduits that extend through the engine and cylinder head. This liquid may be water, but is generally a mixture of water and an antifreeze such as ethylene glycol or propylene glycol. This coolant is then distributed and carried to the radiator to transfer heat from the interior of the fluid to the surrounding ambient air. A pump, such as a centrifugal pump, circulates coolant through the system. This coolant functions in a closed system and is recirculated.

  In the embodiment of FIG. 1, a relatively hot coolant enters the coolant cavity through the coolant inlet 915 and flows around the exterior of the vaporization chamber 900, at the coolant outlet 920. Exit 910. The hot coolant serves to heat the vaporization chamber 900 by transferring heat from the coolant to a relatively cool vaporization chamber. In various embodiments, the exterior of the vaporization chamber can include a plurality of fins and other surface modification elements to increase the amount of heat transferred from the coolant to the vaporization chamber 900. Furthermore, the vaporization chamber can be made of a material with high thermal conductivity to facilitate heat transfer from the coolant to the fuel in the vaporization chamber through the walls of the vaporization chamber. The coolant chamber 905 can be made of a heat insulating material or a material having low thermal conductivity in order to promote heat retention in the coolant chamber and further promote heat transfer to the vaporization chamber 900.

  In the embodiment of FIG. 1, preferably the coolant can be drawn from a standard automotive cooling system, as is well known in the prior art, for example when the coolant is at or near the maximum temperature in a thermostat. . Using the highest temperature coolant for vaporization provides a more efficient effect.

  In addition to the embodiment shown in FIG. 1, the fuel inlet 925 for the vaporization chamber can be a fuel injector as described above. The vaporized fuel outlet 930 is provided such that the vaporized fuel exits the vaporization chamber 900 and is supplied to at least one combustion region. The vaporized fuel outlet 930 is located at the same end as the fuel inlet 925 of the vaporization chamber 900, that is, the vaporized fuel outlet is generally injected along the direction in which the fuel is injected. It is shown not to match the device. This arrangement helps facilitate fuel recirculation in the vaporization chamber before the vapor exits through the vaporized fuel outlet 930. A baffle plate 935 may be provided to prevent newly injected, substantially liquid fuel from being discharged through the vaporized fuel outlet 930. The baffle plate 935 further functions as a heat sink to assist in the evaporation of newly injected fuel that flows through the fuel inlet 925.

  The liquid fuel outlet 940 can be provided inside the vaporization chamber 900 to allow liquid fuel to exit the evaporation volume 901. Since liquid fuel can absorb heat from the coolant and the liquid fuel impairs the usable volume of fuel entering the vaporization chamber for vaporization, the liquid fuel remaining inside the vaporization chamber 900 is left in the vaporization chamber. May be harmful to steam generation. The liquid fuel outlet can be insulated from the coolant cavity 910 by a shielding member 945 to prevent spilled liquid fuel from taking more heat from the system. The liquid fuel removed from the vaporization chamber 900 can be returned to the fuel tank or to the fuel line that supplies the evaporator.

  Another exemplary embodiment of the present invention is illustrated in the vaporizer of FIG. The embodiment of FIG. 2 is similar to the embodiment of FIG. The vaporization chamber 950 is generally surrounded by a coolant chamber 955 that forms a coolant cavity 960 and includes both a coolant inlet 965 and a coolant outlet 970. The illustrated embodiment further includes a fuel inlet 975, shown as a fuel injector, a vaporized fuel outlet 980 for supply to at least one combustion zone, and a liquid fuel outlet for return to the fuel system. 985. The embodiment of FIG. 2 further includes a heat exchange element 990 for providing efficient heat transfer between the vaporization chamber 950 and the incoming fuel spray. The heat exchange element can be a mesh or finned member, but generally includes a region of greater surface area than the surface area that can be used when the heat exchange element 990 is not present. This increased surface area provides a larger heat exchange surface that can be used on the incoming fuel surface to vaporize the liquid fuel more completely and more effectively. Although this heat exchange element can be comprised with what kind of material, in order to accelerate | stimulate the heat exchange between the wall of the vaporization chamber 950 and this heat exchange element, it is preferable to comprise with a material with high heat conductivity.

  The fuel vaporization system of the present invention, particularly in embodiments that do not include an electrical heating element, further provides fuel to the combustion zone under various conditions, such as cold engine starting conditions and high load conditions. Equipment can be included to ensure proper delivery.

  FIG. 3 is a schematic diagram of one exemplary embodiment of the present invention, including equipment that allows cold engine starting and high loads. The conductive path is indicated by a dotted line, whereas the fluid path is indicated by a solid line. The schematic representation of the vaporizer 1000 includes a coolant inlet 1005 and a coolant outlet 1010. The vaporizer 1000 further includes an inlet 1015 for liquid fuel and an outlet 1020 for fuel vapor (vaporized fuel). A liquid fuel outlet may be provided, but the liquid fuel outlet is not shown for simplicity. Liquid fuel is supplied from the fuel tank via fuel line 1025, which supplies fuel in liquid form and / or vapor form to at least one combustion region of the engine. For simplicity of explanation, the high load liquid fuel bypass valve 1040 and the cold engine start liquid fuel bypass valve 1045 are depicted separately, but these valves are a single unit having the same function. Can be coupled to the valve. In this schematic diagram, general components are depicted, but further operating situations will be described here.

  Referring again to FIG. 3, under normal operating conditions (ie, engine coolant is at operating temperature and normal load), the heated engine coolant passes through the coolant inlet line 1005 to the carburetor system. Enter and exit the vaporizer system through coolant outlet line 1010. Liquid fuel flows from the fuel tank along the liquid fuel line 1025 and through valve 1085 and into the liquid fuel inlet 1015 of the vaporizer. Vaporized fuel exits the carburetor at the vaporized fuel outlet 1020, passes through valve 1055, and through fuel line 1030 to at least one combustion region of the engine.

  In the illustrated embodiment, under cold engine start conditions, the temperature sensor 1070, which obtains information from the coolant circulating inside the vaporizer 1000, has a coolant typically 180 ° F. Indicates a non-normal operating temperature between 220 ° F. When an electrical signal is sent from the temperature sensor to the liquid fuel bypass valve 1045 for starting the engine in the cold state, the valve is opened to ensure that at least one combustion region is required for proper operation. As received, liquid fuel is allowed to pass from fuel line 1025 to line 1030 in liquid form. Further, when the coolant temperature is lower than the normal operating temperature, the temperature sensor 1070 signals the valve 1085 and the valve 1055 to close the valve 1085 and the valve 1055, or the valve 1085 and the valve 1055 are closed. To maintain. This is because the liquid fuel enters the vaporizer, eventually the liquid fuel fills the vaporizer, delays the vaporizer from reaching the temperature required to vaporize the fuel, or the vaporizer vaporizes the fuel. To prevent it from reaching the required temperature.

  While functioning normally as described above, the engine can experience high power demands. This high power demand occurs in an automotive engine while accelerating, overtaking, or going up a hill, and in a generator engine when the required wattage is increased by an added electrical load. Occurs. Under these conditions, additional fuel is required because the carburetor sized for optimal efficiency for this application cannot adequately accommodate the instantaneous increase in fuel demand. In the schematic diagram shown, a high load liquid fuel bypass valve 1040 is provided to allow liquid fuel to pass through the vaporizer 1000, and the vaporizer 100 is a high load liquid fuel bypass valve 1040. And liquid fuel is sent from the fuel line 1025 to the combustion region via the fuel line 1040. Under such circumstances, the valve 1085 and valve 1055 may be closed or not closed because the liquid fuel bypass valve 1040 can supplement the vaporized fuel produced by the vaporizer. The control signal 1080 of the liquid fuel bypass valve for high load is increased from, for example, a control module such as an automobile output control module (PCM), a generator engine control device, or a vacuum switch using increased intake pressure. It can be supplied by an electrical signal emitted as an indicator of demand.

  Referring again to the schematic shown in FIG. 3, after a vaporizer has been operating at a steady state operating temperature for a period of time, the vaporizer retains a significant amount of heat. When the engine is shut down, particularly when fuel puddling has previously occurred in the vaporization chamber, steam generation in the vaporization chamber continues for some time, but the coolant flow to the vaporizer also stops. In the illustrated embodiment, an atmospheric release valve 1050 can be provided to limit the maximum pressure in the vaporization chamber and to allow the excessive pressure increased in the vaporizer to be safely returned to the fuel system. A fluid pressure regulator 1075 can provide a signal to the valve, but it can also be configured to open when a predetermined pressure threshold is reached.

As a result of testing the system of the present invention, significant improvements have been observed in the following ranges of government emissions requirements. That is, a reduction in hydrocarbon (HC) content of at least 25%, a reduction in nitrous oxide (NOx) content of at least 70%, and an increase in oxygen (O ₂ ) content of at least 75%.

  While the invention has been described with reference to the drawings attached to this specification, it is noted that apart from those shown or suggested herein, other and further modifications of the invention may be made to the spirit of the invention. This can be done within the scope of the invention.

Claims (14)

A first closed chamber defining a first volume, the closed chamber having a heat conducting surface, the closed chamber having a cylindrical central portion and a spherical end portion; Said first closed chamber being a pressure chamber having:
A second closed chamber at least partially surrounding the first closed chamber and defining a second volume;
A liquid fuel supply system having a liquid fuel supply line for injecting an enlarged pattern of liquid fuel injection into the first volume from at least one orifice spaced from the heat transfer surface;
A thermal fluid system from the engine for circulating a heated fluid through the second volume, transferring heat from the heated fluid through the first closed chamber, and the liquid fuel Said thermal fluid system configured to vaporize;
A vaporized fuel configured to move the vaporized fuel from the first closed chamber to supply fuel to at least one combustion region of the internal combustion engine via a combustion fuel line; Exit,
A pressure relief valve configured to open when the pressure inside the first closed chamber exceeds a predetermined threshold and to move vaporized fuel to the liquid fuel supply system;
A fuel vaporization system for an internal combustion engine.   2. The fuel vaporization system according to claim 1, wherein the heat conducting surface comprises a wall.   3. The fuel vaporization system of claim 2, wherein the heat transfer surface further comprises a member having an increased surface area in thermal communication with the first closed chamber. Vaporization system.   2. The fuel vaporization system of claim 1, further comprising a liquid fuel bypass configured to allow liquid fuel to flow from the edge gas fuel supply line to the fuel supply line for combustion. system.   5. The fuel vaporization system of claim 4, wherein the liquid fuel bypass only meets the requirements of the internal combustion engine only when the first closed volume cannot adequately supply vaporized fuel. The fuel vaporization system configured to open to satisfaction.   2. The fuel vaporization system of claim 1, further comprising a liquid fuel return drain outlet configured to return fuel that has not been vaporized to the liquid fuel supply line.   2. The fuel vaporization system according to claim 1, wherein the first closed chamber includes an upper end and a lower end facing the upper end, and the vaporized fuel outlet is disposed close to the upper end. The fuel vaporization system.   8. The fuel vapor system of claim 7, wherein a fuel injection nozzle is located proximate to the upper end. A method of supplying fuel to at least one combustion region of an internal combustion engine,
Circulating the heated fluid through a chamber at least partially surrounding the vaporization chamber;
Transferring heat from the heated fluid to the vaporization chamber;
Almost liquid fuel is supplied to the vaporization chamber via the liquid fuel supply line,
Vaporizing the substantially liquid fuel in the vaporization chamber to produce fuel vapor pressurized to superatmospheric pressure;
The fuel vapor pressurized to the superatmospheric pressure is discharged from the vaporization chamber to the fuel supply line of the combustion chamber,
When the pressure in the vaporization chamber exceeds a predetermined threshold, the pressure relief valve is opened to move the vaporized fuel to the liquid fuel supply system;
And in order to secure sufficient fuel to meet the fuel demand of the internal combustion engine,
When fuel vapor pressurized to the superatmospheric pressure from the vaporization chamber is not sufficient to satisfy the fuel requirement of the internal combustion engine, an electrical signal is received at the liquid fuel bypass valve;
Receiving the signal, at least partially opening the liquid fuel bypass valve; and
Bypassing the vaporization chamber at least partially by diverting liquid fuel from the liquid fuel supply line to a line supplying fuel to the combustion chamber via the liquid fuel bypass valve;
This ensures sufficient fuel to meet the fuel demand of the internal combustion engine,
A method of supplying fuel to at least one combustion region of an internal combustion engine.   10. The method of supplying fuel to at least one combustion region of an internal combustion engine as recited in claim 9, wherein the method further includes returning liquid fuel from the vaporization chamber to the liquid fuel supply line. Supplying a fuel to at least one combustion zone. A fuel vaporizer for an internal combustion engine, wherein the fuel vaporizer is
A closed pressure chamber defining a volume;
A heat conducting surface associated with the volume and arranged to be heated;
A liquid fuel supply system, arranged to inject an enlarged pattern of liquid fuel spray into the volume under superatmospheric pressure from at least one orifice spaced from the heat conducting surface, wherein the liquid A fuel supply system is a flow rate control comprising the liquid fuel supply system, which injects fuel into an evaporation volume and supplies the fuel to at least one combustion region of the internal combustion engine, and at least one fuel vapor injection device. Each of the at least one fuel vapor injection device is configured to communicate directly or indirectly with the respective at least one combustion region and to operate in response to an output demand of the internal combustion engine; Thereby, the pressurized fuel vapor can flow into the internal combustion engine while a substantially superatmospheric pressure is maintained in the closed pressure chamber. The flow rate control,
The closed pressure chamber and the liquid fuel supply system are configured and arranged with respect to the heat transfer surface to form a mixing region between the at least one orifice and the heat transfer surface; In the mixing zone, the fuel spray is recirculated heated fuel vapor that has previously traveled over the heat transfer surface and received heat from the heat transfer surface as it advances through the volume from the orifice. Is substantially heated and vaporized by mixing with
The fuel vaporizer communicates with a steam outflow passage for flowing pressurized steam into the closed pressure chamber to be supplied to the at least one combustion region;
The heat transfer surface is arranged to be at least partially heated by an internal combustion engine coolant circulating around the exterior of the closed pressure chamber;
A fuel vaporizer for an internal combustion engine.   12. The fuel vaporizer of claim 11, wherein a second closed chamber at least partially surrounds the closed pressure chamber and defines a volume for circulating the coolant of the internal combustion engine. The fuel vaporizer.   13. The fuel vaporizer of claim 12, wherein the second closed chamber further comprises an engine coolant inlet and an engine coolant outlet, through the engine coolant inlet. The fuel vaporizer wherein the engine coolant flowing in is hotter than the engine coolant flowing out through the engine coolant outlet.   12. The fuel vaporizer of claim 11, wherein the closed pressure chamber further comprises a liquid fuel return outlet configured to return unvaporized fuel to the liquid fuel supply system. Vaporizer.

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