Patent Publication Number: US-3877449-A

Title: Pressure carburetor system for manifold distribution

Description:
[4 1 Apr. 15, 1975 1 1 PRESSURE CARBURETOR SYSTEM FOR MANIFOLD DISTRIBUTION Carl F. High, 1758] Appoline, Detroit, Mich. 48235 June 14, 1973 [76] Inventor:  
 [22] Filed:  
  [21] Appl. No.: 363,946  
 Related US. Application Data [63] Continuation-in-part of Ser. No. 119,591, March 1, 1971, abandoned, which is a continuation-in-part of Ser. No. 11,572, Feb, 16, 1970, abandoned.  
 [52] US. Cl 123/119 R; 261/79; 123/131; 123/141; 123/136; 123/119 B [51] Int. Cl. F02b 33/00; F02m 7/00 [58] Field of Search 123/119 R, 131, 136, 141; 261/79 [56] References Cited UNITED STATES PATENTS 1,199,747 9/1916 Benhank 261/79 1,211,714 l/l9l7 Kirbach 261/52 1,525,956 2/1925 Sargent 261/79 1,600,007 9/1926 Mock 123/141 1,901,847 3/1933 Moore l l 261/69 1,901,849 3/1933 Moore 123/131 2,251,999 8/1941 Greco l 123/141 2,587,360 2/1952 Milbrath l 123/141 2,701,557 2/1955 Ramey 123/141 3,336,017 8/1967 Kopa 261/79 3,391,679 7/1968 Williams 123/136 3,395,899 8/1968 Kopa 123/119 Primary ExaminerCharles J. Myhre Assistant Examiner-Ronald B. Cox  
 Attorney, Agent, or FirmHauke, Gifford, Patalidis &amp; Dumont [57] ABSTRACT A charge forming system for an internal combustion engine in which a pressure carburetor incorporates a centrally located vertically disposed cylindrical mixing chamber, disposed immediately upstream of the intake manifold inlet and opening directly thereto. The chamber is defined by a cylindrical air valve which has a plurality of annularly spaced air inlet ports formed in the cylinder wall registering with corresponding tangential air inlet ducts formed in the carburetor housing for tangentially introducing air into the air valve. The air valve may be rotated about a vertical axis to vary the amount of registration between the inlet ports formed in the valve and the inlet ducts, thereby varying the amount of air introduced into the mixing chamber or, as shown in another modification, the air valve consisting of a simple cylinder may be vertically shifted within the peripheral housing to vary the opening of the inlet ducts over the upper end of the valve. In a third preferred embodiment, the cylindrical air valve is replaced by one or more butterfly valves situated in one or more air inlet passages, which are formed to tangentially introduce air into the mixing chamber. A downwardly directed fuel nozzle is disposed at the top or closed end of the mixing chamber for spraying a metered supply of atomized fuel axially therein, whereby the spray is mixed with the air before it is inducted into the intake manifold.  
 14 Claims, 9 Drawing Figures PATENTEUAFR 1 5197s I @877. 449  
 sum 1 u; g  
 INVENTOR CARL F. HIGH BY g PMM ATTORNEYS PATENTEBAPRISISYS sumsu z&#39;z PIC-3 5 FIG.6  
 I III FIG-7 2% Tlulm Hill  INVENTOR CARL F. HIGH BY HM, KW 5&#39; $2M ATTORNEYS PRESSURE CARBURETOR SYSTEM FOR MANIFOLD DISTRIBUTION CROSS REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of my application Ser. No. 119,591 filed Mar. 1, 1971, now aban doned, which was a continuation-in-part of my application Ser. No. 11,572 filed Feb. l6, 1970 and now abandoned, and represents an improvement over my U.S. Pat. No. 3,635,201 issued Jan. 18, 1972 on an application co-pending with the applications from which the present application derived.  
 BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to internal combustion engine charge forming control systems for pressure carburetion with manifold distribution of the charge.  
 2. Description of the Prior Art Reduction of discharge residue and resultant toxic gases emitted by internal combustion engines, particularly in automobiles and large commercial vehicles such as trucks and buses, has received substantial attention in recent years. The reason for this attention has been part of a total effort aimed at reducing smog or polluted air concentrations in the larger cities.  
  Efforts toward reducing the discharge residue from internal combustion engines has been directed toward the improvement of the engine combustion characteristics, since by optimizing the combustion process fewer unburned and partially burned components are available for discharge to the atmosphere. These efforts have so far been only sporadically successful.  
 SUMMARY OF THE INVENTION The present invention illustrates a pressure carburetion-manifold distribution system provided with the features deemed important for the solution of the problem of engine generated air pollution. The system improves engine combustion characteristics by thoroughly diffusing and mixing the fuel and air and by completely vaporizing the atomized fuel in the fuel-air charge, thereby reducing the quantity of unburned hydrocarbons and carbonmonoxide. The system substan tially simulates the performance of liquid petroleum gas or propane, which burns clean in the combustion chamber with the exhaust gases substantially free of emissions. Formation in the combustion process of nitric oxide, which becomes toxic nitrogen dioxide upon its introduction into the atmosphere, is prevented by the introduction into the fuel-air mixture, during the upper ranges of the engine operation, of a difinite quantity of engine exhaust gases and a fog of water raising the humidity of the inducted mixture. The introduction of exhaust gases and the water fog cools the combustion processes. thereby avoiding the heat plus pressure combination which otherwise causes the formation of nitric oxide.  
  The preferred embodiment of the invention comprises a carburetor housing having a swirl-type mixing chamber disposed immediately upstream of the engine intake manifold. The chamber in some modifications is formed within a centrally located cylindrical air va-lve mounted in the carburetor housing and rotatable about a central vertical axis or axially movable within the housing chamber. The carburetor housing includes a plurality of tangential air inlet ducts, or a peripheral air inlet chamber provided with swirl-producing vanes, the ducts or spaces between the vanes arranged either to register with a plurality of air valve inlet ports tangentially formed in the side walls of the rotatable air valve or to introduce air over the top edge of the cylindrical valve. Rotation of the rotatable air valve or axial movement of the valve varies the registration of the ports and ducts or the degree of opening of the ducts to thereby vary the amount of air introduced into the mixing chamber formed in the center of the air valve. The tangential admission of air into the mixing chamber causes the air to swirl at a substantially high velocity in the mixing chamber before it is inducted into the engine intake manifold.  
  A fuel nozzle assembly is disposed immediately about or at the closed end of the mixing chamber and has its fuel outlet nozzle extending axially downwardly into or toward the mixing chamber and in line with the outlet from the mixing chamber for discharging a metered quantity of atomized fuel towards the mixing chamber outlet into the swirling air within the air valve. Thus, the tangentially entering air swirls inwardly around the mixing chamber, thoroughly mixing with the fuel spray before the mixture is inducted into the intake manifold. A surface heated by the engines exhaust gases is disposed within the intake manifold immediately downstream from the mixing chamber outlet, aiding in the vaporation of the fuel. The chamber opening to the manifold may be of reduced diameter to form an orifice which enhances the mixing of the fuel spray throughout the swirling air and directs the mixture in a definite pattern against the exhaust heated surface of the manifold. The swirling fuel-air charge is then relatively uniformly distributed to the cylinder intake port runners opening from the intake manifold.  
  In an improved modification, an adapter plate is mounted between the carburetor and manifold structures and has an opening communicating same which is formed to initiate directional flow of the mixture toward the port runners leading from the manifold.  
 DESCRIPTION OF THE DRAWINGS The description refers to the accompanying drawings wherein like reference characters refer to like parts throughout the several views, and in which:  
  FIG. 1 is a top plan view of a preferred embodiment of the pressure carburetionmanifold distribution system with the air cleaner removed for clarity and partially broken away to illustrate some components in cross-section;  
  FIG. 2 is a cross-sectional view of the system taken substantially on line 2-2 of FIG. 1;  
  FIG. 3 is a fragmentary cross-sectional view of the system of FIG. 1 showing the construction of a preferred metering valve;  
  FIG. 4 is a fragmentary cross-sectional view of the system shown in FIG. 1 showing detailed construction of the connection between the air valve and the fuel metering piston;  
  FIG. 5 is a vertical cross-sectional view of another preferred embodiment of the invention;  
 FIG. 6 is a top plan view of the system of FIG. 5;  
  FIG. 7 is a fragmentary cross-sectional view taken pn the line 77 of FIG. 5;  
  FIG. 8 is a vertical cross-sectional view of a third preferred embodiment of the invention; and  
  FIG. 9 is a fragmentary cross-sectional view taken on line 9-9 of FIG. 8.  
 DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 and 2, a preferred pressure carburetion manifold distribution fuel-air mixture induction system comprises a preferred intake manifold, generally indicated at 10, for an eight cylinder V-type engine. The manifold includes a central chamber 12 connected with a plurality of annularly spaced intake port runners 14 leading to each of the engines cylinders (not shown). The chamber 12 is provided with a central fuel-air mixture intake port 16 that registers with a fuel-air mixture outlet 18 of a mixing chamber 20, which is centrally located in a carburetor housing 22. The housing 22 is secured to the intake manifold by any convenient means and has a gasket plate 24 disposed therebetween to retain a hereafter described valve 34 and to prevent leakage.  
  The present system is designed for use primarily with the manifold shown, but may be adapted to other manifolds as is or with some modifications, but the principles herein described are the same.  
  Referring to FIG. 1, the housing 22 is formed preferably with four vertically disposed air inletchannels 26, 28, 30 and 32 positioned around a centrally located rotatably mounted cylindrical air valve 34. Each of the air inlet channels includes a duct, indicated at 36, 38; 40 and 42, respectively, extending in a counter-clockwise direction from the respective inlet channel around the air valve 34 to the outlet ports 44, 46, 48 and 50, respectively, with which are engaged the outer surface of the cylindrical wall of the air valve 34. As shown in FIGS. 1 and 2, the air valve 34 has four vertically extending annularly spaced air inlet ports 52, 54, 56 and 58, which register with the air outlet ports 44, 46, 48 and 50, respectively, for receiving air therefrom into the mixing chamber formed within the air valve 34. Thus. air for engine operation is inducted into the air inlet channels 26, 28, and 32, and through the connecting ducts 36, 38, and 42 to the air outlet ports 44, 46, 48 and 50. When the incoming air reaches the air outlet ports, it is moving counter-clockwise, as viewed in FIG. 1. This counter-clockwise movement is continued as the air passes from the air outlet ports through the air inlet ports 52, 54, 56 and 58 and into the mixing chamber 20. Thus, air entering the mixing chamber 20 swirls counterclockwise around the mixing chamber before it is inducted through the fuel-air mixture oulet 18 formed in the valve 34 and into the central chamber 12 of the intake manifold.  
  It will be noted that the vertically disposed edge surfaces of the air inlet ports 52, 54, 56 and 58 are formed so as to aid in directing the incoming air tangentially into the mixing chamber 20 along the inner wall of the air valve 34. Specifically, vertical edge surfaces, 60, 62, 64 and 66 of the air inlet ports 52, 54, 56 and 58, respectively, are slanted clockwise from a radial line through their respective point of intersection with the outer wall of the valve 34 so as to be substantially tangential to the inner wall surface of the valve 34 and, thus, not hinder the incoming air from tangentially entering the chamber 20. Each of the opposite vertical edge surfaces 68, 70, 72 and 74 of the air inlet ports are curved toward the edge surfaces 60, 62, 64 and &#34;66, respectively, in extending from their intersection with the outer wall of the valve 34 to their intersection with the inner wall of the valve. Thus, the edge surfaces 68, 70, 72 and 74 also aid in directing incoming air counterclockwise around the mixing chamber 20.  
  Referring to FIG. 2, it will be noted that the inlet port 54 extends (as do the inlet ports 52, 56 and 58) almost the entire vertical length of the air valve 34. If it is desired to use the system on smaller sized engines, the ports 52, 54, 56 and 58 may be formed in the air valve 34 so as to extend a lesser vertical distance.  
  Referring to FIGS. 1 and 2, a fuel nozzle assembly 76 is mounted on a supporting structure 78 which is a part of the housing 22 and extends over the top opening of the cylindrical air valve 34, preventing air from entering therethrough. The fuel nozzle assembly 76, the detailed construction and operation of which is shown and described in my US. Pat. No. 3,635,201, issued Jan. 18, 1972, includes a downwardly directed fuel outlet 80 disposed within the upper portion of the mixing chamber 20 for spraying a finely atomized spray of metered fuel into the mixing chamber, as indicated by the lines 82. Thus, the spray of fuel from the outlet 80 is swirled counterclockwise around the mixing chamber 20 by the counterclockwise swirling air, thoroughly mixing the fuel spray with the air before the mixture is inducted into the intake manifold, thereby forming a&#39; better burning mixture that results in the formation of less pollution. From the mixing chamber 20, the mixture passes through the outlet 18 into the intake manifold, thereby forming a better burning mixture that results in the formation of less pollution. From the mixing chamber 20, the mixture passes through the outlet 18 into the central chamber 12 where it engages a surface and the swirling of the fuel-air charge ensure an evendistribution of the charge to the individual cylinders.  
  As previously described, the air valve 34 is rotatably mounted about its central vertical within the housing 22 for varying the quantity of air entering the mixing chamber 20 by varying the size of the openings into the chamber 20 formed by the air outlet ports 44, 46, 48 and 50 and the air inlet ports 52, 54, 56 and 58. Referring to FIG. 1, as the air valve 34, which is shown in the full open position, is rotated counter-clockwise about its central axis, the registration between the outlet ports and the inlet ports decreases, decreasing the quantity of air entering the mixing chamber 20.  
  As seen in FIGS. 1 and 2, the valve 34 has a horizontally disposed elongated lever 84 extending radially outward from its lower portion between the housing 22 and the gasket plate 24 for rotating the valve about its central axis. The lever 84 has an aperture 86 formed adjacent its free end for receiving a loop 88 formed on one end of a coil spring 90. The spring 90 has a second loop 92 formed on its other end extending into an aperture 94 formed in a fixed support 96 secured to the housing 22, thereby stretching the spring 90 between the support 96 and the lever 84. Thus, the spring 90 urges the valve 34 counter-clockwise toward a position closing the air inlet ports formed in the valve.  
  A lever 98, having one end 100 hooked around the loop 88 of the spring 90 immediately beneath the lever 84, has its other end attached to a conventional footoperated acceleration pedal (not shown). As the foot pedal is pushed downward, the lever 98 is pulled toward the left, as viewed in FIG. 1, rotating the valve 34 clockwise against the force of the spring 90, increasing the quantity of air flowing into the mixing chamber 20 by increasing the open area between the air inlet ports and the air outlet ports.  
  Fuel to the fuel nozzle assembly 76 is metered through a pair of variable orifice valves shown in FIGS. 1, 3 and 4. Fuel from a main fuel tank (not shown) is delivered by the action of a fuel pump (not shown) into a fuel chamber 102. The flow of fuel from the main fuel tank into the fuel chamber 102 is controlled by a variable orifice valve assembly 104 which is responsive to intake manifold pressure to increase fuel flow into the chamber 102 as the intake manifold pressure increases. The detailed construction and operation of the valve assembly 104 is more fully shown and described in my co-pending application Ser. No. 857,415, now U.S. Pat. No. 3,635,201.  
  Referring to FIGS. 3 and 4, the fuel chamber 102 is formed with a boss 106 having a fuel outlet orifice 108. A variable orifice piston 110 is closely fitted in and axially movable in a chamber 112. The chamber 112 has an outlet orifice 114 connected by conduit 116 with the outlet orifice 108. The piston 110 is formed with a tapered groove 118, which intersects the orifice 1.14 for metering fuel from the fuel chamber 102 into an accumulator chamber 120 which forms a part of the chamber 112. A conduit (not shown) leads from the accumulator chamber 120 and connects to a conduit 122, as shown in FIGS. 1 and 2, which leads to the fuel nozzle assembly 76 for delivering liquid fuel thereto. The piston 110 forms a variable orifice 124 between the left end of the close fitting portion of the chamber 112 and the tapered groove 118 for metering the fuel. As the piston moves to the left, as viewed in FIG. 3, the effective cross-section of the metering orifice 124 increases due to the taper of the groove 118, thereby increasing fuel flow from the fuel chamber 102 into the conduit 122 and to the fuel nozzle assembly 76. The piston 110 has its end opposite the accumulator chamber 120 pivotally connected to a flange 126 by means of a pin 128. The flange 126 is integrally formed with and extends radially outward from the lower portion of the valve 34 and has the vertically disposed pin 128 threaded therein. The upper portion of the pin 128 extends into an elongated aperture 130 formed in the piston 110. Thus, as the valve 34 is rotated clockwise as shown in FIG. 1, the stud 126 is pushed to the left, as shown in FIG. 3, thereby pushing the piston 110 to the left and increasing the opening of the orifice 124, delivering more fuel from the chamber 102 to the fuel nozzle as sembly 76. Thus, as the valve 34 is rotated to allow more air to flow into the mixing chamber 20, the orifice 124 is simultaneously opened to increase fuel delivery.  
  It is noted that when the valve 34 is quickly rotated clockwise allowing air to rush into the intake manifold for quick acceleration, the piston 110 is quickly moved to the left, as viewed in FIG. 3, forcing the free end of the piston into the accumulator chamber 120, and immediately displacing a portion of the fuel therein to provide the greater quantity of fuel needed to mix with the sudden rush of air.  
  A fuel shut-off valve 132, as illustrated in FIG. 3, may be provided for manually shutting off the fuel to prevent a gravity fuel flow from an elevated fuel tank into the carburetor. The valve 132 includes an elongated needle valve 134 slidably mounted in a cylinder 136 formed in the housing 22. The valve 134 includes a conical tip 138 disposed in the fuel chamber 102 for insertion into the outlet orifice 108 for stopping the flow of fuel from the fuel chamber 102. The valve 134 includes an O-ring 140 positioned therearound to prevent leakage of fuel from the chamber 102. Appropriate linkage may be secured to the valve 134 to actuate 1t.  
  Referring to FIG. 1, a variable idler stop system 142 is provided to give a higher idling speed during engine warm-up. The system 142 includes an elongated horizontally disposed member 144 slidably mounted on the housing 22 and having one end engaging the lever 84 when the valve 34 is positioned in the idle position. The lever 144 is actuated by an elongated vertically disposed member 146 pivotally mounted at its lower end on a pin 148. The upper end &#39;of the member member 146 is pivotally secured to a lever 150 by means of a pin 152. A cam 154 is formed on the lower edge of the member 146 to actuate the lever 144 as the member 146 is pivoted about the pin 148 by the lever 150, thus varying the idle stop position of the air valve 34 and simultaneously the fuel metering piston 110. The lever 150 is connected to a diaphragm assembly 153, as shown and described in my U.S. Pat. No. 3,635,201, responsive to intake manifold pressure for varying the idle stop position.  
  As described in my aforementioned U.S. Pat. No. 3,635,201, the nozzle assembly 76 may be selectively alternatively vented to atmospheric air and hot engine exhaust gases. Referring to FIG. 1, a conventional diaphragm snap-acting valve assembly 155 is shown for selectively alternatively directing air and hot engine exhaust gases to the nozzle assembly 76 through conduit 156. Although the specific construction of the valve 154 may be of any convenient design, its operation and purpose may be as previously described in my US. Pat. No. 3,635,201.  
  Referring to FIG. 1, a water spray system 158 is shown, its operation and construction previously shown and described in my U.S. Pat. No. 3,635,20l. It will be noted that the water spray system 158 includes a nozzle 160 for spraying water through the inlet port 56 into the mixing chamber 20.  
  Referring to FIG. 1, a chamber 162 for venting the crankcase fumes is formed in the housing 22 for the reception of adhesionplates 164. The chamber 162 is communicated with the engine crankcase, as by passage 170, for receiving engine crankcase fumes there from. The crankcase receives ram-air via the rockerbox covers (not shown) from the T-pipe 172. The crankcase fumes are inducted into one end of the chamber 162 and weave back and forth between the plates 164 before exiting through an aperture 166 formed in the chamber 162. Simultaneously with the fumes from the crankcase, evaporative losses of fuel from the condensing chamber of the sealed fuel tank, as shown in my U.S. Pat. No. 3,635,201, are transferred to the inlet of the chamber 162 through the tube 174. The aperture 166 communicates with a port 168 formed in the air valve 34 for drawing the crankcase fumes and evaporative losses into the mixing chamber 20. It will be noted that the port 168 is formed with a wide opening on the outer surface of the valve 34 so that the chamber 162 communicates with the mixing chamber irrespective of the angular position of the air valve 34.  
  FIGS. 5, 6 and 7 illustrate another preferred embodiment of the invention in which an intake manifold 210 has a central chamber 212 connected with a plurality of annularly spaced intake port runners 214 leading to each of the engines cylinders (not shown). The chamber 212 is provided with a central fuel-air mixture intake port 216 which registers with a reduced orifice fuel-air mixture outlet 218 ofa mixing chamber 220 located in the carburetor housing 222.  
  The housing 222 is formed with an annular outer air intake chamber 224 provided with vertical vanes 226 extending from the outer peripheral wall of the chamber 224 tangentially to the inner peripheral wall of the chamber 224, and inner vane elements 228 located in annularly spaced positions around the inner peripheral wall of the chamber 224 and formed to cooperate with the vanes 226 to form channels 230 leading tangentially into the mixing chamber 220. Air enters the upper end of the chamber 224 from a conventional air intake filter (not shown).  
  A cylindrical air valve 234 is disposed within the mixing chamber 220 for vertical movement therein so that its upper edge will selectively variably open the channels 230 into the mixing chamber 220, so that air for engine operation is inducted into the intake chamber 224, through the channels 230, and tangentially into the mixing chamber 220 to produce a substantially high velocity air swirl therein.  
  A fuel nozzle assembly 276 is mounted on the top of the housing 222, its detailed construction and operation being shown and described in my U.S. Pat. No. 3,635,201 and operates to inject a finely atomized spray of metered fuel axially downwardly into the mixing chamber 220. The fuel spray is swirled around the mixing chamber 220 by the swirling air, thoroughly mixing the fuel spray with the air before the mixture is inducted into the intake manifold, as previously described for the embodiment of FIGS. 1-4. From the mixing chamber 220, the mixture passes through the smaller diameter outlet orifice 218 which operates to more thoroughly mix the fuel spray with the swirling air and to direct it in a definite pattern into the intake manifold 210 and aganist a preferably ribbed surface 283 which is heated by hot engine exhaust gases as described in the aforesaid patent, for the previously described purposes.  
  The valve 234 is provided near its lower end with outwardly extending pins 284 which are engaged in slots 286 provided in the ends of the lever arms 288. The arms 288 are fulcrummed at their other ends on pins 290 mounted in the carburetor housing 222. A rotatable shaft 292 extends through the housing 222 and has eccentric portions 294 which engage in slots 296 provided in the lever arms 288 intermediate the pins 284 and 290, so that rotation of the shaft 292 can lower and raise the air valve 234 between the upper position shown and a lower position as indicated in phantom lines to variably open and close communication between the channels 340 leading from the outer air intake chamber 224 into the mixing chamber 220. The shaft 292 may be rotated by any preferred mechanism in relation to the injection of fuel into the mixing chamber to thereby provide the desired fuel-air mixture for optimum operation of the engine.  
  FIGS. 8 and 9 illustrate a third preferred embodiment of the invention in which the intake manifold 310 has a distribution chamber 312 connected with a plurality of port runners 313 (one only being shown), leading to each of the engines cylinders (not shown). The chamber 312 has an upper fuel-air mixture inlet opening 316 which registers with one end of a contoured passage 318 extending through a mounting plate 320. The other end of the mounting plate passage 318 registers with a fuel air mixture outlet 324 of a mixing chamber 326 located in a carburetor housing 328.  
  The passage 318 in the mounting plate 320 is formed so as to initate directional flow of the fuel-air mixture to each of the port runners 313, but such contouring will in the intake manifold be individually de&#39;signed for each different type of engine with which the present invention is to be used, and the shape of the mounting passage 318 in FIG. 8 is merely illustrative.  
  A housing 329 includes a pair of cylindrical air inlets 330 and 332 arranged in parallel and having throttle valves 334 and 336, respectively. The throttle valves 334 and 336 are secured to rotatably mounted shafts 338 and 340 that are mechanically linked together (not shown) and connected to a foot operated accelerator pedel (not shown) by any conventional means. As the foot pedal is pushed downward, shaft 340 is rotated in a counterclockwise direction and shaft 338 is rotated in a clockwise direction thereby opening the throttle valves 334 and 336 to induct a variable air flow into air inlets 330 and 332, depending on the degree of depression of the accelerator pedal.  
  As the throttle valves 334 and 336 are opened, air from the air inlets 330 and 332 is inducted by the suction pressure of the intake manifold 310 into air channels 382 and 384, respectively, of the mixing chamber 326. The beginning of the channel 382 is formed by an outer wall 386, a backwall 387 and an inner wall 388. The inner wall 388 extends upward from the outer periphery of the outlet 324 of the mixing chamber 326 and slopes downward afterwards the outlet 324 ad the channel 382 curves counterclockwise around the outlet 324 to the channel outlet 389, where the wall 388 terminates. The beginning of of the channel 384 is formed by the outer wall 390, a backwall 391 and an inner wall 392. The inner wall 392 extends upwardly from the outer periphery of the outlet 324 and slopes downward towards the outlet 324 and the channel 382 curves counterclockwise around the outlet 324 to the channel outlet 389, where the wall 388 terminates. The beginning of the channel 384 is formed by the outer wall 390, a backwall 391 and an inner wall 392. The inner wall 392 extends upwardly from the outer periphery of the outlet 324 and slopes downward toward the outlet 324 as the channel 384 curves counterclockwise around the outlet 324 to the channel outlet 393, where the wall 392 terminates.  
  The suction pressure of the intake manifold 310 inducts the air in the channels 382 and 384 in a counterclockwise direction, as illustrated in FIG. 9 by arrows 394 and 396, toward the central outlet 324 of the mixing chamber 326. The air tangentially enters the central outlet 324 where it swirls the fuel sprayed from nozzle 344, as previously described in the first embodiment and in my US. Pat. No. 3,635,201, so as to diffuse the sprayed fuel and mix it evenly with the air. The mixture then swirls axially through the outlet 324 and the opening 318 in the mounting plate 320, and into the central chamber 312 of the intake manifold 310. As the fuelair mixture moves into the intake manifold 310, it sweeps across a heated surface 346 of an exhaust crossover passage 348 which further aids in the vaporization of the fuel.  
  Although I have described but three preferred embodiments of my invention, it is to be understood that various changes and revisions can be made therein without departing from the spirit of the invention or the scope of the appended claims.  
 I claim:  
  1. In an internal combustion engine having an intake manifold adapted to distribute a fuel-air mixture to engine cylinders, a fuel-air charge forming system comprising:  
 a carburetor housing having a mixing chamber defined by a cylindrical recess open at one end for communication at all times openly and directly with said intake manifold and closed at the opposite end, a liquid fuel nozzle carried at said closed end substantially at the chamber axis and adapted to inject an atomized fuel spray substantially axially into said chamber toward said open end,  
 means for regulating fuel flow to said nozzle,  
 at least one air intake passage in said housing directing air to an intake port opening into the side of said mixing chamber, valve means disposed within said housing adjacent said mixing chamber and operable upon actuation to regulate air flow into said mixing chamber,  
 means connecting said fuel flow regulating means and said valve means to increase air flow into said chamber as fuel flow increases and to decrease the air flow into said chamber as fuel flow decreases; and  
 said intake passage and said valve means being formed to direct air tangentially to said intake port to swirl air inwardly into said mixing chamber for mixing with the liquid fuel spray from said fuel nozzle prior to discharge into said manifold.  
  2. The system of claim 1 wherein said valve means is associated with said intake port opening for selectively varying the cross-sectional area thereof.  
  3. The system of claim 1 wherein said valve comprises a tubular member fitting within the side wall of said chamber.  
  4. The system of claim 1 wherein said valve is rotatable in said chamber and has at least one port variably registerable with said intake port on rotation of said valve.  
  5. The system of claim 4 wherein said intake port and said valve port extend longitudinally parallel to said chamber axis.  
  6. The system of claim 4 wherein said valve port has bevelled edges to augment tangential entry of air into said chamber.  
  7. The system of claim 3 wherein said valve is axially movable in said chamber with one end variably opening said air intake port to said chamber.  
  8. The system of claim 7 wherein said air intake port is disposed adjacent the fuel nozzle end of said chamher.  
  9. The system of claim 7 wherein said intake port extends longitudinally parallel to said chamber axis.  
  10. The system of claim 1 including an adapter plate mounted intermediate said carburetor housing and said intake manifold, said intake manifold having two or more port runners, said plate having an opening therethrough with one end thereof registering with said chamber open end and side walls thereof formed selectively to initiate directional distribution of said mixture from said chamber toward the port runners of said manifold with respect to the engine with which the system is used.  
  11. The system of claim 1 and including a surface heated by the exhaust gases of said internal combustion engine disposed down-stream of said mixing chamber for aiding in the vaporizing of the atomized fuel discharged from said mixing chamber.  
  12. The system of claim 1 and including an idle stop mechanism responsive to engine manifold pressure associated with said valve means for varying the engine idle setting of said valve.  
  13. The system of claim 1 and including means for venting fumes from the engine crankcase into said mixing chamber.  
  14. The system of claim 1 and including means for venting evaporative losses from the fuel system into said mixing chamber.  
 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3 3,877, 449 DATED April 15, 1.975  
 INVENTOR(S) Carl F. High it is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:  
 Col. 2, line 64, delete &#34;pm&#34; and insert --on- Col. 3, line 51, delete &#34;oulet&#34; and insert --outlet-- Col. 4, line 43, after &#34;vertical&#34; insert --aXis-- Col. 5, line 26, delete &#34;outlet&#34; and insert --inlet- Signed and sealed this 15th day of July 1975.  
 (SEAL) Attest:  
  C. MARSHALL DANN RUTH C. MASON Commissioner of Patents Attesting Officer and Trademarks