Abstract:
A process in which liquid fuel is saturated with a gas to provide a fuel/gas solution said fuel/gas solution fed to a combustion engine, a first portion of said fuel/gas solution that is fed to said combustion engine is combusted, a second portion of said fuel/gas solution that is fed to said combustion engine is not combusted, the temperature of said second portion of said fuel/gas solution is reduced in a heat exchanger to produce a reduced temperature second portion, evaporated gas in said reduced temperature second portion is then removed in a separator, and the fuel/gas solution thus produced is then fed back into the combustion engine.

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATION 
       [0001]    This application claims priority based upon provisional application 61/504,409, filed on Jul. 5, 2011. 
     
    
     FIELD OF THE INVENTION 
       [0002]    A process for activating fuel in which a fuel is contacted with gas in an absorber comprised of a multiplicity of gas permeable tubes. 
       BACKGROUND OF THE INVENTION 
       [0003]    Several prior art patents describe processes for “activating fuel” in which a solution of gas and fuel is prepared, and such material is then combusted. Reference may be had, e.g., to U.S. Pat. No. 6,273,072 of Knapstein, U.S. Pat. No. 7,523,747 of Gachik et al.; U.S. Pat. No. 8,037,849 of Staroselsky, and the like. The entire disclosure of each of these United States patents is hereby incorporated by reference into this specification. However, the prior art processes are not very efficient. It is an object of this invention to provide a more efficient process for activating fuel and using it in a diesel engine. 
       SUMMARY OF THE INVENTION 
       [0004]    In accordance with this invention, there provided a process in which liquid fuel is saturated with a gas to provide a fuel/gas composition, said fuel/gas composition is fed to a combustion engine, a first portion of said fuel/gas composition that is fed to said combustion engine is combusted, a second portion of said fuel/gas composition that is fed to said combustion engine is not combusted, the temperature of said second portion of said fuel/gas composition is reduced in a heat exchanger to produce a reduced temperature second portion, evaporated gas in said reduced temperature second portion is then removed in a separator, and the composition thus produced is then fed back into the combustion engine. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]      FIG. 1  is a schematic of one preferred process of the invention&#39; 
           [0006]      FIG. 2  is a sectional view of one preferred absorber that used in the process of the invention; 
           [0007]      FIG. 3  is a perspective view of the absorber of  FIG. 2 ; and 
           [0008]      FIG. 4  is a partial sectional view of the common rail of a diesel engine. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0009]      FIG. 1  is a schematic diagram of a fuel supply system  10  comprised of a counter-flow absorber  12 . 
         [0010]    Referring to  FIG. 1 , a common rail  88  off diesel engine  14  is connected to a single fuel supply line through an absorber  12 . Thus, in this embodiment, in all operational modes the fuel is supplied to the engine through the absorber  12 . 
         [0011]    Referring again to  FIG. 1 , a fuel tank  18  is comprised of a fuel  20  that, in one embodiment, preferably, is diesel fuel. In another embodiment, not shown, the fuel is gasoline. 
         [0012]    The diesel fuel from tank  18  is then fed via line  22  to filter  24  to remove impurities. The filtered fuel is then fed through line  26  to check valve  28  and then to fuel pump  30 . The fuel then pumped through line  32  to differential pressure regulator  34 . 
         [0013]    In one embodiment, the pressure of the fuel that passes through regulator  34  is preferably from about 20 to 200 pounds per square inch. 
         [0014]    The reduced pressure fuel is then fed into absorber  12 .  FIG. 2  is a sectional view of one embodiment of absorber  12 . 
         [0015]    Referring to  FIG. 2 , such  FIG. 3  shows a cross-section view of one embodiment of a counter-flow absorber providing a gas absorption by fuel flow in film mode. The absorber  12  is preferably cartridge type absorber. The cartridge  36  preferably comprises a plurality of tubes  38 . 
         [0016]    In one embodiment, the tubes  38  have outside diameters of from about 100 to about 1,000 microns and, preferably, inside diameters from about 400 to about 600 microns. The tubes  38  are preferably comprised of a gas permeable material such as, e.g., a gas permeable membrane. Thus, e.g., one may use the same type of material as is used in kidney dialysis cartridges. 
         [0017]    Referring again to  FIG. 2 , the fuel is fed into the absorber  12  and flows inside the tubes  38 . In the embodiment depicted in  FIG. 2 , the gas is fed via line  40  and flows outside the tubes  38 . The gas permeates through the walls of the tubes  38  and forms a solution within such fuel. 
         [0018]    In the preferred embodiment depicted, there is “counter-flow,” that is, the fuel downwardly in the direction of arrow  42 , while the gas flows upwardly. 
         [0019]    Referring again to  FIG. 1 , gas is fed through line  50  to compressor  52 . In one embodiment, such gas is air. In another embodiment, the gas is carbon dioxide. In another embodiment, the gas may be argon. It is preferred, in one embodiment, to use air. 
         [0020]    The air fed through line  52  is then compressed to a pressure that is higher than the pressure of the fuel. In one embodiment, the pressure of the compressed air is from about 1 to about 10 pounds per square inch higher than the pressure of the fuel and, more preferably, from about 1 to about 5 pounds per square inch higher than the pressure of the fuel. 
         [0021]    Referring again to  FIG. 1 , the compressed air is fed into a receiver  54  which, preferably, is part of the compressor assembly. The compressed air is connected to a solenoid valve  56  that is operatively connected to a controller (not shown). Compressed air from the solenoid valve  56  to gas pressure regulating valve  58  which insures that the compressed air is at a proper pressure vis-à-vis the pressure of the fuel. A controller (not shown) is connected to sensors (not shown) and such valves, and it maintains the desired pressure differential within the absorber  12 . 
         [0022]    Referring again to  FIG. 2 , and as a result of this process, the gas penetrates through the membrane tubes  38  and is absorbed by fuel forming a “fuel/gas” solution. The “fuel/gas” solution exits through the outlet port  60  is preferably at ambient temperature, and it preferably is at substantially the same temperature as is the fuel  20  within tank  18 . 
         [0023]    In one embodiment, the fuel/gas solution that exits through outlet port  60  is at a pressure of at least 20 pounds per square inch, but preferably about 90 pounds per square inch. 
         [0024]    The fuel/gas solution is then fed through a pressure regulator  62 , which, in one embodiment, reduces the pressure from about 15 to about 30 percent. Thereafter, the reduced pressure material fuel/gas solution is fed to a Y connector  64  where it is mixed with a feed from regulator  66 . 
         [0025]    The regulator  66  is feeding excess fuel in return line from engine  14 . Such fuel is fed via line  68  and passes through valve assembly  70  and then through line  72  to the three way ball valve  74 . The excess fuel is then passed through a heat exchange  76  in which its temperature is reduced to substantially ambient temperature, and the reduced temperature fuel/gas solution then passed through regulator  66  and mixed at Y connector  64 . The regulator  66  keep the back pressure in return line  72 . 
         [0026]    In one embodiment, the pressure of the feeds into Y connector  64  is substantially equal. The combined feed is then fed via line  78  to a gas/vapor separator  80 . Excess gas with fuel vapor is then fed via line  82  to the intake of the engine. 
         [0027]    The purified fuel feed from separator  80  is then fed via line  17  to a high pressure secondary pump  84 , and the (fuel/gas solution free from gas bobbles) is pumped through a filter  86  to the inlet port of the common rail  88  of the engine. 
         [0028]      FIG. 4  is a schematic view of common rail  88 , illustrating the fuel/gas solution being fed in the direction of arrow  90 , and excess fuel is withdrawn in the direction of arrow  92  and recycled via line  72  (see  FIG. 1 ). 
         [0029]    Referring again to  FIG. 1 , and in the preferred embodiment depicted therein, an exit port  100  feeds gas into line  102  and then through check valve  104 , venture valve  106  and solenoid valve  108  to separator  80 . In one embodiment, the fuel supply system of this invention comprises:
       a countercurrent-flow absorber;   a Y-connector with a downstream pressure reducing regulator to mix a fresh “fuel/gas” solution with the return fuel flow;   a gas separator;   a high pressure fuel pump to raise the pressure of the “fuel/gas” solution to operational pressure inside the common rail;   a return fuel line for the excess fuel exiting the common rail;   a three-way valve to direct return fuel flow either to the engine through a heat exchanger and upstream pressure regulator or to the fuel tank.       
 
         [0036]    A low pressure pump pumps the fuel from the fuel tank to the absorber. A part of the fuel drawn from the fuel tank flows through the heat exchanger to cool down the return fuel flow. A differential pressure regulator sets the fuel pressure in the absorber lower than the gas pressure at the outlet of the absorber. In the absorber the fuel picks up the gas penetrating through the gas permeable walls of the tubes. The fuel enters the absorber in upper zone and gas enters in lower zone. As the fuel and gas flow in the absorber in opposite directions the gas dissolves in the fuel in pseudo-fluidized liquid/gas mode. The formed “fuel/gas” solution exits the absorber through the bottom port and flows to the Y-connector. A downstream pressure regulator sets the pressure of the “fuel/gas” solution in line with the pressure of the return fuel flow. Any free gas bubbles existing in the mixed fuel solution are separated in the gas-vapor separator. The high pressure fuel pump pressurizes the fuel/gas solution to the operational pressure in the common rail. Excess fuel solution exiting the common rail is directed by the three-way ball valve to the heat exchanger and then to the Y-connector through the back pressure regulator. The gas (air, CO 2 , or HC gas) is supplied to the absorber by a compressor, and the pressure of the gas is set by a pressure regulator. When the engine operates on the “base” fuel, e.g., at idling, start or shut down then the gas chamber of the absorber is filled with fuel by closing solenoid valve  56  and opening for a short period of time (about 3 to 40 sec) of solenoid valve  108 . 
         [0037]    Similar result (saturated “fuel/gas” solution) can be achieved by many other methods, and the membrane cartridge type absorber allows simplifying the design and reduces dimensions of the whole fuel system. 
         [0038]      FIG. 4  shows a two-stage common rail according to the invention which allows exclude the possibility to supply fuel with free gas bubble to injectors. The fuel solution enters common rail through an inlet port. The bottom stage has several outlet ports connected with injectors. The excess fuel exits the common rail through an outlet port at upper stage. Both stages are connected by several passages to remove free gas bubbles that may appear in fuel solution under uncontrollable circumstances from bottom stage that supply fuel to injectors. 
         [0039]    As will be seen from the aforementioned description, and in one preferred embodiment, the pressure is regulated by a differential pressure regulator; the activated liquid fuel/gas solution after the absorber is fed to a y-connector where it is mixed with the returned fuel, a free gas/fuel vapors are separated from the mixed fuel flow; the separated gas/fuel vapors are directed to the engine air supply line; the liquid fuel flow is fed to the high pressure fuel pump and further to the engine injectors. 
         [0040]    In one embodiment, at engine operations other than idling the gas section of the absorber is filled with the gas/gases; and during idling periods the gas section of the absorber is preferably filled with the fuel. 
         [0041]    In one embodiment, the system contains, in addition to components of the standard fuel system such as a fuel tank, fuel filters, fuel pumps, etc., the following:
       an absorber for dissolving gas/gases in the liquid fuel, the absorber provides the high contact interface of the liquid fuel and gas/gases using, e.g. gas diffusion membrane tubes;   a double-deck common rail which design excludes an appearance of the free gas phase at the bottom stage of the common rail feeding the liquid fuel solution to injectors; the fuel solution is supplying to the common rail through the bottom stage and the excess fuel is returned from the upper stage of the common rail; both stages are connected with each other to provide an escape to the free gas bubbles forming e.g. at engine stall or shutdown;   an absorber fuel supply subsystem, including a differential pressure regulator and a solenoid valve in the supply line;   a subsystem for removing free gas/fuel vapors from the fuel supply line into the air supply line;   a subsystem for mixing the fuel solution after the absorber with the returned fuel.