Fuel Evaporation Apparatus and Method

Since the advent of the internal combustion engine, various attempts have been made to provide a fuel supply system which increases the efficiency of the burning of the fuel. Applicant is aware of several United States Patents which are generally directed to this subject matter and briefly discusses them below:

U.S. Pat. No. 541,773, now U.S. Pat. No. D278,291 to Mead which discloses a vaporizer which is heated by exhaust fumes from the exhaust system. The vaporizer includes a central pipe through which petroleum from the fuel tank passes on the way to the engine.

U.S. Pat. No. 1,997,497 to Pogue which discloses a two-stage vaporizer including a first stage wherein atmospheric air bubbles the fuel to vaporize it. From there, the fuel enters a tortuous path vaporizer which is heated by exhaust gases to further vaporize the fuel. The fuel exits from the tortuous path vaporizer and is swept down through a venturi passage to mix with air and enter the cylinders.

U.S. Pat. No. 2,049,687 to Chamberland, et al., discloses a vaporizing chamber connected into the exhaust line as a heat source and including fuel connections. An air jet helps to atomize the entering fuel which is then vaporized and conducted to the outlet and intake manifold.

U.S. Pat. No. 2,306,897 to Ollig discloses a device which includes a spiraling chamber heated with exhaust manifold fumes. Fuel is conducted into the chamber through a pipe whereupon it is heated and vaporized, thence exiting out of the chamber whereupon it is mixed with air and the mixture enters the intake manifold. Unvaporized fuel runs down the spiral and exits through an outlet back to the fuel tank.

U.S. Pat. No. 2,650,582 to Green discloses a vaporizer which is heated by exhaust gas through various pipes. Fuel is mixed with air to help vaporize it whereupon it enters a vaporizing chamber to further vaporize. Upon leaving the chamber, further mixture with air is had and then the mixture is conducted to the intake manifold.

U.S. Pat. No. 3,872,191 to Walcker discloses a heating coil which may be heated by coolant or hot exhaust gases. A circular tube sprays fuel directly on a screen. The temperature of the screen being elevated, the fuel vaporizes off the screen and air mixes with therewith, with the mixture then entering the intake manifold.

U.S. Pat. No. 4,015,569 to Leshner et al., discloses a device wherein liquid fuel is metered to a vaporizing chamber which is heated by exhaust gases. The fuel is vaporized and then conducted to the engine intake where it is mixed with air in the manifold or cylinders.

U.S. Pat. No. 4,106,457 to Totten et al., discloses a fuel vaporizer including a first chamber heated by exhaust gas and a second serially arranged unheated baffle chamber and a distribution chamber. Fuel passes through the various chambers where it is vaporized whereupon it is mixed with air and conducted to the engine intake manifold.

U.S. Pat. No. 4,139,582 to Collins discloses a heat exchanger including tubes through which exhaust gas travels to heat the associated chamber. Fuel is heated in the chamber whereupon it is mixed with the air and then heated in a further chamber and thence conducted to the engine intake manifold.

U.S. Pat. No. 4,151,821 to Wichman et al., discloses a fuel supply system wherein engine exhaust is used to heat a fuel atomization chamber. The fuel is conducted therein, vaporized and then fed through a metering valve to mix with air.

U.S. Pat. No. 4,212,274 to Quick discloses a chamber into which exhaust gases are conducted to heat same. Liquid gas droplets are centrifuged in a second chamber adjacent to the first mentioned chamber and thereby vaporized.

U.S. Pat. No. 4,213,433 to Day discloses an annular doughnut-shaped vaporizer which is heated by exhaust gases and thus vaporizes gasoline entering therein. After such vaporization the gas is conducted to a venturi to mix with incoming air.

U.S. Pat. No. 4,223,652 to Budnicki discloses an exhaust gas heated vaporizer through which fuel is conducted. The fuel is vaporized and thence mixed with air.

U.S. Pat. No. 4,349,001 to Wagner discloses a cylindrical vaporizer with fuel inlet jets. As disclosed, coolant is used to provide heat to the vaporizer.

While some of these patents teach some of the aspects of the instant invention, applicant believes that none of them teach, either singly or in combination, all of the inventive features combined into applicant's invention.

The invention disclosed herein includes a plurality of separate components combined together to form a fuel supply system for an internal combustion engine. Fuel is conducted to a two-stage evaporator. A first stage of this evaporator includes a manifold for supplying the fuel to a chamber via a plurality of micro-ports. In the chamber, in the preferred embodiment, a pair of thermal discs are mounted in spaced relationship. Each thermal disc includes a plurality of heating elements which serve to heat the thermal discs to a predetermined controlled temperature. As the fuel exits the above described micro-ports, it is partially atomized by the size of the micro-ports. The fuel, after exiting the micro-ports, impinges upon the thermal discs to thereby be vaporized. As the fuel vaporizes, the chamber fills with vaporized fuel which then enters the second stage of the evaporator in accordance with the present invention.

The second stage of the improved fuel evaporator comprises, in the preferred embodiment, a second chamber concentrically arranged with respect to the above described chamber. In this second chamber, an elongated conduit is provided in a spiral configuration winding around the circumference while traversing from an inlet at the top of the second chamber to an outlet at the bottom of the second chamber. Within this second chamber, ports are also provided for supply and exhaust of, for example, exhaust fumes from the operation of the internal combustion engine, which are used in order to heat the fuel within the spiral conduit.

After the vaporized fuel has been further heated and further expanded within the spiral conduit, the now completely vaporized fuel exits the spiral conduit at the bottom thereof via a T-shaped outlet fitting. This fitting provides two outlets, a first of which connects via a conduit with a vapor fuel block directly and a second of which communicates via a conduit to the vapor fuel block via a vapor pump. The vapor fuel block supplies the vapor control valves situated on the venturi stack of the carburetor stage of the invention. The branch which supplies the vapor fuel block via the vapor pump is provided so that in times of increased demand, such as during acceleration, the bypass tube and vapor pump may be utilized so as to extract larger volumes of vaporized fuel for supply to the venturi stack and thereafter to the engine.

The improved fuel evaporation process disclosed herein includes other features which are necessary in the particular applications to which such a device will be put. For example, cold start valves are provided which directly supply fuel from the fuel tank to the venturi stack for cold starting purposes. Further, idle adjustment devices are provided which enable the adjustment of the operation speed of the engine during idle.

Accordingly, it is a first object of the present invention to provide an improved fuel supply system for an internal combustion engine.

It is a further object of the present invention to provide a fuel supply system for an internal combustion engine which increases the efficiency in the burning of the fuel-air mixture thereof.

It is a still further object of the present invention to increase the efficiency of the burning of fuel in an internal combustion engine through the use of a two-stage evaporator system which completely evaporates and expands the fuel before it is mixed with air.

It is a yet further object of the present invention to provide the evaporator system with unique thermal discs which enable the efficient evaporation of the fuel in a first stage thereof.

It is a yet further object of the present invention to provide, in a second stage thereof, a spirally configured conduit heated by, for example, exhaust gases as a second stage of the evaporator.

These and other objects, advantages and features of the present invention will become apparent from the following detailed description of the preferred embodiments when considered in conjunction with the accompanying drawings.

FIG. 1 shows a perspective exploded view of a preferred embodiment of the present invention with portions broken away to show detail.

FIG. 2 shows a further perspective view of the present invention taken from a different orientation from that of FIG. 1.

FIG. 3 shows a perspective view of the structure of the thermal discs and their electrical connections in one preferred form thereof.

With reference, now, to FIG. 1, the improved fuel evaporator apparatus 1 is seen in exploded perspective view. The apparatus includes a two-stage evaporator section 10 and a venturi-fuel block section 100. The two-stage evaporator section 10 includes a housing 11 including a bottom plate 13, a top plate 15 and four substantially concentric, substantially cylindrical walls 17, 19, 21 and 23 disposed substantially perpendicularly between the bottom and upper plates 13 and 15. The wall 17 defines therewithin a chamber 18 into which portions of the venturi-fuel block 10 protrude and into which an air cleaner (not shown) may be mounted.

The wall 21 is located at substantially the periphery of the bottom plate 13 and defines along with the wall 23 and top and bottom walls 25, 27 a chamber 22 in which a spiral conduit 29 is mounted. The wall 23 is slightly longer than the wall 21 so that the bottom wall 27 is slightly below the bottom plate 13 as shown in FIG. 1. The bottom wall 27 extends parallel to the bottom plate 13 so as to define therebetween a portion of the chamber 22 which allows exhaust gases therein to heat the bottom plate 13 and thereby any unvaporized fuel impinging thereon in the chamber 33. The spiral conduit 29 is provided with an inlet fitting 31 which protrudes into a chamber 33 defined between the walls 19 and 21 and is further provided with an outlet fitting 35 which may, if desired, protrude through the bottom wall 27 of the chamber 22.

The top plate 15 is connected with the wall 17 as seen in FIG. 1, while the wall 19 is attached to the bottom plate 13 along with the wall 21. The top plate 15 includes extending downwardly therefrom an annular chamber 37 formed by a wall structure 39. An inlet fitting 38 connects this chamber 37 with the fuel tank 41 via the fuel pump 42 and fuel filter 43. The wall structure 39 includes a plurality of micro-openings 40 which communicate the chamber 37 with the chamber 33 for a purpose to be described hereinafter.

As further shown in FIG. 1, the wall 19 has mounted thereon a pair of thermal discs 45 and 47. As shown, the thermal disc 45 extends slightly less than half way radially across the chamber 33 and is connected to the wall 19 by an angular member 49 and suitable fastening means 48 and 50. The thermal disc 47 extends almost entirely across the radial extent of the chamber 33 and is attached to the wall 19 by angular member 51 and suitable fastening means 52 and 53. At spaced positions throughout the circumferential extent of the respective thermal discs 45 and 47, radial holes 55 are formed therein. Each hole 55 is dimensioned to snugly receive therein a heating element 57 which may, if desired, comprise a glow plug. The details of the electrical connection of the heating elements 57 into the electrical system of the vehicle will be described in greater detail hereinafter with reference to FIG. 3.

As noted above, the chamber 22 is provided for the purpose of containing exhaust gases conveyed therein for the purpose of heating the spiral conduit 29 and vapors contained therein, as well as for heating the bottom of plate 13, as well as any unvaporized fuel impinging thereon within chamber 33. In order to convey exhaust fumes into the chamber 22, an inlet fitting 59 is provided and outlet fitting 61 is provided so as to enable the conveyance of exhaust fumes away from the chamber 22 as desired. The inlet fitting 59 has connected thereto a conduit 63 having a valve 64 therein. The outlet fitting 61 includes a temperature sensor 65. If desired, the temperature sensor 65 may be interconnected with the valve 64 so that the temperature at the outlet fitting 61 of the exhaust fumes may be sensed and from this sensed temperature, the inlet valve 64 for the exhaust fumes may be suitably controlled so as to control the temperature to which fuel vapors within the spiral conduit 29 are exposed.

As further shown in FIG. 1, the bottom plate 13 of the evaporator portion 10 includes a pair of rectangular holes 67 and 69 therethrough. These holes are provided so as to enable the venturi stacks of the venturi-fuel block portion 100 of the invention to protrude therethrough in assembly. As also shown in FIG. 1, the bottom wall 27 has similar rectangular holes aligned with the holes 67 and 69 and provided for the same purpose. As shown in FIG. 1, the venturi-fuel block section 100 includes a primary venturi stack 101 which fits through the opening 69 in the plate 13 of the evaporator 10 and a secondary venturi stack 103 which fits through the opening 67 in the plate 13 of the evaporator 10, as well as through the holes in bottom wall 27. As shown, the venturi stacks 101 and 103 have extending therethrough respective cold start valves 105 and 107 which connect directly to the vehicle fuel tank 41 via the pump 42, filter 43 and the conduit 106 including branches 106a and 106b. The cold start valves 105 and 107 are provided for the purpose of enabling the engine to be started in cold weather and when it has not been used for a long period of time. Accordingly, the cold start valves 105 and 107 are only intended to be used for starting the engine and the fuel supply valve 108 located in the line 106 may be shut off either automatically or manually after starting of the engine has been accomplished.

With further reference to FIG. 1, it is seen that the apparatus 100 further includes a fuel block 110 which comprises a manifold for conveying fuel vapors from the apparatus 10 to the venturi stacks 101 and 103. The fuel block 110 includes input ports 111 and 113. As noted hereinabove, the spiral conduit 29 includes an outlet fitting 35. This outlet fitting 35 comprises a T-type fitting including an inlet port 32, and outlet ports 34 and 36. The outlet port 34 of the fitting 35 is connected to the inlet port 111 via a flexible conduit 115 directly. The output port 36 of the fitting 35 is connected to the inlet port 113 of the fuel block 110 via a flexible conduit 117, a vapor fuel pump 119 and a further conduit 121. As such, it is seen that one branch defined by the conduit 115 supplies fuel directly to the fuel block 110 without pumping thereof, while a further branch supplies fuel to the fuel block 110 via conduits 117 and 121 with the vapor pump 119. Thus, when a high demand for fuel vapor exists such as, for example, during acceleration of the associated vehicle, the vapor fuel pump 119 may be activated so as to enable the supply of vaporized fuel in whatever quantity is desired to the venturi stacks 101 and 103.

As noted above, the fuel block 110 comprises a manifold for distributing fuel received thereby to the respective venturi stacks 101 and 103. In this regard, the fuel block 110 includes output ports 123 and 125. The output port 123 connects via a conduit 124 with a vapor control valve 127 mounted on the secondary venturi stack 103. Further, the output port 125 connects via a flexible conduit 126 with a vapor control valve member 129 operatively connected to the primary venturi stack 101. The vapor control valves 127 and 129 include respective screw adjustment members 131 and 133 so as to enable the adjustment of the idle speed of the associated engine. Also mounted to the venturi stacks 101 and 103 are a plurality of bracket members 135 which are provided so as to enable the correct alignment of the venturi-fuel block apparatus 100 with the evaporator apparatus 10 during the assembly thereof. With further reference, now, to FIG. 2, it is seen that the venturi stacks 101 and 103 are mounted on a base member 137 which contains the respective valves therein. Mounted at the bottom of the primary venturi stack 101 are a pair of primary valves 139 while mounted at the bottom of the secondary venturi stack 103 are a pair of secondary valves 141. A linkage 143 is shown mounted on the side of the plate 145 and this linkage 143 is connected to control structure well known to those skilled in the art which is utilized to operate the valves 139 and 141 to thereby control the flow of air therethrough which is mixed with fuel vapor entrained therein.

With reference now to FIG. 3, the electrical connections for the heating elements 57 will now be described in greater detail. FIG. 3 shows the thermal discs 45 and 47 as mounted to the wall 19. In the preferred arrangement of electrically connecting the glow plugs 57 with batteries 81 and 81', the glow plugs 57 are connected together in groups of six glow plugs with three glow plugs in this group being located in the thermal disc 45 and the other three in this group of six being located in the thermal disc 47. As shown in FIG. 3, each group of six glow plugs includes a first electrical conductor 70 which commonly connects together the glow plugs 57 located in the thermal disc 45. The group further includes an electrical conductor 71 which electrically connects together the glow plugs 57 located within thermal disc 47. A further electrical conductor 72 electrically interconnects the electrical conductors 70 and 71. An electrical wire 75 is connected at a location somewhere on one of the electrical conductors 70, 71 and 72 and connects with a junction box 77 or 77' as shown. As such, in the embodiment shown in FIG. 3, the electrical junction box 77 includes four electrical wires 75 connected thereto to thereby enable the control of 24 glow plugs 57 while the electrical junction box 77' has connected thereto four wires 75 so as to enable the control thereby of twenty-four further glow plugs 57. The electrical junction box 77 is connected to the battery 81 via electrical conductors 79 which connect to the terminal section 83, whereas the battery 81' is connected to the electrical junction box 77' via electrical conductors 79' which connect to the electrical terminals located at 83'.

As further shown in FIG. 3, the thermal disc 45 may have a temperature sensor 85 mounted while the thermal disc 47 may have a temperature sensor 87 mounted thereto. These temperature sensors 85 and 87 connect to a control box 89 via electrical wires 86 and 88, respectively. The control box 89 is electrically connected to electrical switches 90 and 92 which respectively control the electrical current through electrical wires 79 and 79'. Accordingly, the control box 89 may be programmed in a manner well known to those skilled in the art so as to enable the sensing of the temperature of thermal discs 45 and 47 and when this temperature exceeds a predetermined desired temperature, causing the opening of the switches 90 and 92. When the temperature of the thermal discs 45 and 47 reduces below a predetermined temperature, the control box 89 senses this via the temperature sensors 85 and 87 and acts to close the switches 90 and 92 to thereby enable the heating of the thermal discs 45 and 47 by the glow plugs 57.

Now, the operation of the present invention will be described with reference to FIGS. 1-3. As noted above, fuel is supplied to the trough 37 from the fuel reservoir 41 via the fuel pump 42, filter 43 and inlet fitting 38. The pressure provided by the fuel pump 42 acts to force the fuel out of the micro-pores 40 in the trough 37 in a fine, mist-like spray. The thermal discs 45 and 47 having been heated by the glow plugs 57, fuel impinging thereon vaporizes. Further, fuel impinging upon the wall 21 of the chamber 22 is also heated and vaporizes due to the presence of exhaust fumes within the chamber 22 which act to heat the wall 21. The suction created by the fuel demand at the venturi stacks 101 and 103 causes the fuel vapor to be sucked into the port 31 and to then flow through the spiral conduit 29 wherein the fuel vapor is further heated through the above noted presence of exhaust fumes within the chamber 22. After traversing the spiral conduit 29, the fuel exits the spiral conduit 29 via the fitting 35 and progresses to the fuel block 110 via the conduit 115 on the one hand and via the conduit 117, pump 119 and conduit 121 on the other hand. As noted hereinabove, the pump 119 is operable during periods of great vapor demand to be activated so as to pump larger volumes of fuel vapor into the fuel block 110.

Vaporized fuel enters the fuel block 110 and is conveyed to the outlet ports 123 and 125 which respectively supply the vapor control valves 127 and 129 located on respective secondary and primary venturi stacks 103 and 101. The valves 139 and 141 are controlled in a manner known to those skilled in the art to thereby control the flow of air through the venturi stacks 101 and 103 and to thereby entrain into the air flow, fuel vapors which have been conveyed to vapor control valves 129 and 127.

The vapor pump 119 may be interconnected with the accelerator pedal of the vehicle so that when the accelerator pedal is depressed in a manner so as to open up the secondary valves 141, the vapor pump 119 is simultaneously activated to thereby provide larger volumes of vapor thereto.

When the engine has not been used for long periods of time or, for example, on cold mornings, the cold start valves 105 and 107 may be utilized through the control of the valve 108 to supply fuel directly to the venturi stacks bypassing the evaporator 10. As noted hereinabove, the valve 108 may be controlled by a timer or by a temperature sensor or other means so as to cut off the supply of fuel to the valves 105 and 107 after the engine has sufficiently warmed up.

The flow of exhaust gases through the chamber 22 is controlled by the temperature sensor 65 which senses the temperatures and acts through control means (not shown) to control the opening and closing of the valve 64 so as to control the flow of exhaust gases in the chamber 22. Similarly, as best seen in FIG. 3, the temperature sensors 85 and 87 located in the respective thermal discs 45 and 47 sense the temperatures thereof and send signals indicative of the temperatures to a control box 89 which acts to control the flow of current to the glow plugs 57 to thereby control the temperature of the thermal discs 45 and 47 to a desired temperature range.

Accordingly, an improved fuel supply system for an internal combustion engine has been disclosed which fulfills each and every object delineated hereinabove. It is contemplated that various modifications, alterations and changes in the teachings of the present invention may occur to those skilled in the art. Accordingly, it is intended that the invention should not be limited to the embodiments specifically described herein, but rather that the invention disclosed herein should only be limited by the scope of the appended claims.