US3635201A

US3635201A - Pressure carburetion system for manifold distribution

Info

Publication number: US3635201A
Application number: US857415A
Authority: US
Inventors: Carl F High
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-09-12
Filing date: 1969-09-12
Publication date: 1972-01-18
Anticipated expiration: 1989-01-18

Abstract

A charge-forming system for an internal combustion engine in which a pressure carburetor incorporates a whirl-type mixing chamber disposed immediately upstream of the intake manifold inlet. A pair of parallel cylindrical air inlet ducts, each having a mechanically operated throttle valve therein, are disposed immediately upstream of the mixing chamber for controlling air induction thereto. A fuel nozzle supported intermediate the two air inlet ducts sprays a metered supply of atomized fuel into the mixing chamber, where the spray is mixed with the air from the air inlet ducts and the mixture then discharged into the intake manifold. The fuel-air mixture entering the intake manifold impinges surface heated by the engine exhaust gases to aid in the vaporization of the fuel. The fuel to the fuel nozzle is pressure-varied relative to manifold pressure and mechanically metered relative to air throttle operation. A manually operated fuel shutoff and a manifold pressure controlled idle stop are also provided. A controlled charge of water is injected into the fuel-air mixture by a spray jet operated from engine exhaust gas pressure relative to manifold pressure changes.

Description

I United States Patent 1151 3,635,201 High 51 Jan. 18, 1972 54] PRESSURE CARBURETION SYSTEM 3,036,564 5/1962 011101 ..123/119 FOR MANIFOLD DISTRIBUTION 3,395,899 8/1968 Kopa ..261/22 [72] Inventor: Carl F. High, 17581 Appolini, Detroit, FOREIGN PATENTS OR APPLICATIONS 48235 391,535 5/1933 Great Britain ..123/144 [22] Filed: Sept. 12, 1969 Primary Examiner-Al Lawrence Smith [21] Appl 857'415 Attorney-Haukc, Gifford and Patalidis 52 us. c1 ..123/130,123/119, 123/131, [571 ABSTRACT 123/139 AW, 123/141, 239/404, 261/51, 261/7 A charge-forming system for an internal combustion engine in [5 1 1 Int. 8 a pressure carburetor incorporates a whirl-type mixing Field of Search 119 chamber disposed immediately upstream of the intake 1 19 5 2 103 manifold inlet. A pair of parallel cylindrical air inlet ducts, 261/79, 69, 36.1, 51, 69 each having a mechanically operated throttle valve therein,

are disposed immediately upstream of the mixing chamber for [56] References Cited controlling air induction thereto. A fuel nozzle supported intermediate the two air inlet ducts spraysa metered supply of UNITED STATES PATENTS atomized fuel into the mixing chamber, where the spray is 1 305 174 5/1919 Smith .....4s/1s0 mixed with the inlet ducts and the mixture then discharged into the intake manifold. The fuel-air mixture 2,131,950 10/1938 High 123/103 E 2 205 458 6/1940 Ban 123/103 E entering the intake manifold impinges surface heated by the 25o307l 4/1950 123/52 M engine exhaust gases to aid in the vaporization of the fuel. The 8 5/1959 Kl g 123/139 fuel to the fuel nozzle is pressure-varied relative to manifold 2916270 12/1959 D g 261/37 pressure and mechanically metered relative to air throttle 2'969784 l 1961 F a 139 operation. A manually operated fuel shutoff and a manifold lg pressure controlled idle stop are also provided. A controlled 114741693 11/1923 Morse 239/404 charge of water is injected into the fuel-air mixture by a spray jet operated from engine exhaust gas pressure relative to 1 1 00m ifold re s e cha es. 2,072,353 3/1937 Ball ...123/52 M x mm p S M 2,562,936 8/1951 Moore et al ..123/144 X 5 Claims, 23 Drawing Figures /z2 36, i -252 ha I? 1 11 1 36 L 1'1 46 /242 44 /-34 we 7 l W l ill &5 7 r: E i 4/37 1 l x l 1 f 5 I 33 em 3 2e 24 2o 3 g 2/3 t 24 24 24 l 32%- g 98 2L 100 & m4 102 loz @5 3/2 PATENTED JAN 1 8 I972 SHEET 3 [IF 4 I uuvamon v CARL F. men I IH W ATTORNEYS ll] r PATENTEU JAN 1 8 m2 SHEET '4 BF 4 may 224 I INVENTOR 32 CARL r. men as; 'fw

lav/M ATTORNEYS PRESSURE CARBURETION SYSTEM FOR MANIFOLD DISTUTION 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 The 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 ci-' ties.

Efforts toward reducing the discharge residue from internal combustion engines has been directed at 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 comprises a pressure carburetionmanifold distribution system provided with the features deemed essential for the solution of the problems of enginegenerated air pollution. The system effects improvement of the 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 carbon monoxide. The formation in the combustion process of nitric oxide, which becomes the toxic nitrogen dioxide upon its introduction into the atmosphere, is prevented by the introduction into the fuel-air mixture during the upper ranges of engine operation of a definite quantity of engine exhaust gases and a fog of water raising the humidity of the inducted mixture, cooling the combustion process to avoid the heat plus pressure combination which produces formation of nitric oxide in the exhaust.

The preferred embodiment of the invention comprises a swirl-type mixing chamber disposed immediately upstream from the engine intake manifold. The chamber includes a central open area opening into the intake manifold. A fuel nozzle disposed upstream from the mixing chamber has its fuel outlet in line with the outlet of the mixing chamber for discharging a metered quantity of atomized fuel toward the mixing chamber outlet. A pair of cylindrical parallel air inlet ducts disposed on opposite sides of the fuel nozzle have their outlets adjacent the fuel nozzle for the induction of air into the mixing chamber, where it is swirled around the centrally located open area of the mixing chamber, to whirl the fuel spray from the nozzle so that the air is thereby thoroughly mixed with the fuel spray before the mixture is inducted into the intake manifold. A surface heated by the engine exhaust gases is disposed within the intake manifold immediately downstream from and in line with the mixing chamber outlet, to aid in the vaporization of the fuel.

The metered fuel to the fuel nozzle is provided from a fuel control including a variable orifice metering valve to which fuel is supplied by a pressure-varying valve responsive to manifold pressure variations. The metering valve comprises an axially movable piston having a longitudinal tapered slot for varying the orifice size and, consequently, the quantity of fuel delivered to the fuel nozzle. The piston is actuated through a direct mechanical linkage from the manual throttle control. Associated with the movable piston is a variable idle stop for providing higher idling speeds for engine warmup. A diaphragm-spring arrangement sensitive to intake manifold pressure is provided to vary the idle stop condition.

The fuel nozzle includes a main housing having a fuel passage with fuel-whirling vanes therein for the passage, and an annular whirl space formed around the housing by a tubular shell. The annular space is selectively vented to hot exhaust gases or air by a snap-action valve responsive to intake manifold pressure such that the annular space is vented to air during engine idling to prevent aspirating the fuel line and to aid in the combustion process, and is vented to hot engine exhaust gases during higher speed operation of the engine to aid in atomizing the fuel.

A filtering chamber communicating with the engine crankcase and one of the cylindrical air inlet ducts 'aids in venting the crankcase fumes. During high-speed engine operation ram-air into the crankcase is scooped from the intake of the engine air induction system to pressurize and force the crankcase fumes through the filtering chamber and into the carburetor air inlet. During low-speed operation and engine idling, a vacuum is created in the intake manifold thereby inducting the crankcase fumes through the crankcase into the filtering chamber and into the air inlet where they are delivered to the engine cylinders for burning.

The system further includes a sealed water tank pressurized by engine exhaust during high-speed operation, and a nozzle for introducing a fine spray of water into one of the air inlet ducts to provide controlled humidity for cooling the combustion processes, thereby helping prevent the formation of nitric oxide, which otherwise is converted to nitrogen dioxide when released into the atmosphere.

DESCRIPTION OF THE DRAWINGS The description refers to the accompanying drawings wherein like reference to characters refer to like parts throughout the several views and in which:

FIG. l is a top plan view of a preferred embodiment of the pressure carburetion-manifold distribution system with the air cleaner and control linkage elements removed for clarity;

FIG. 2 is a cross-sectional view of the system taken substantially on line 2-2 of FIG. 1;

FIG. 3 is a cross-sectional view of the system taken substantially on line 3-3 of FIG. 2;

FIG. 4 is an elevational view of the system as seen from the top side of FIG. 1;

FIG. 5 is a cross-sectional view of the system taken substantially on line 5-5 of FIG. 2;

FIG. 6 is an elevational view of the system as seen from the bottom side of FIG. 1;

FIG. 7 is a cross-sectional view of the system taken on line 7-7 of FIG. ll;

FIG. 8 is a top view of the preferred embodiment of the nozzle assembly;

FIG. 9 is a bottom view of the nozzle assembly shown in FIG. 8;

FIG. 10 is a front view of the nozzle assembly shown in FIG.

FIG. 1 I is a cross-sectional view of the nozzle assembly taken substantially on line Ill-ll of FIG. 10;

FIGS. lllA', NB, NC, and MD are cross-sectional views taken substantially on lines MA, HE, "C and ND, respectively, of FIG. 111;

FIG. 12 is a cross-sectional view of the nozzle assembly taken substantially on line 12-112 of FIG. 111;

FIG. 12A is a cross-sectional view taken substantially on line 12A of FIG. 12;

FIG. 13 is a cross-sectional view of the system taken substantially on line 13-13 of FIG. 1;

FIG. 114 is an elevational view of the system as seen from the left side of FIG. ll;

FIG. 15 is an elevational view of the preferred embodiment of the crankcase venting chamber;

FIG. 16 is a top view of the venting chamber shown in FIG. 15;

FIG. 17 is an elevational view of the venting chamber as seen from the bottom of FIG. 16; and

FIG. 18 is an elevational view of the system as seen from the right side of FIG. ll.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. 1, 2 and 3, a preferred pressure carburetion-manifold distribution fuel-air mixture induction system comprises a preferred intake manifold, generally indicated at 20, for an eight cylinder V-type engine. A central chamber 22 has a plurality of intake runners 24 leading to each of the engine cylinders (not shown). The chamber 22 is provided with a central fuel-air mixture intake port 26 that registers with a fuel-air mixture outlet 28 of a mixing chamber 30, which is formed in a chamber housing 32. The housing 32 is secured to the intake manifold by any convenient means with a gasket 33 disposed therebetween to prevent leakage.

An air intake housing 34, as shown in FIGS. 1 and 2, is mounted on top of the mixing chamber housing 32 and secured thereto by means of screws 35. A gasket 37 is disposed between the

housings

32 and 34 to prevent leakage therebetween. The housing 34 comprises a pair of

cylindrical air inlets

36 and 38 arranged in parallel and having

throttle valves

40 and 42, respectively. The

throttle valves

40 and 42 are secured to rotatably mounted

shafts

44 and 46 that are mechanically linked together as is shown in FIG. 6. The shaft 46 has a lever 48 secured thereto with an opening 50 formed in its free end for attachment to a conventional foot-operated accelerator pedal (not shown). As the foot pedal is pushed downward, the lever 48 and the shaft 46 are rotated counterclockwise, toward the dotted line position indicated in FIG. 6, opening the throttle valve 42. A lever 52 having one end secured to the shaft 46 has an opening 54 formed in its free end for receiving one end of a linkage rod 56. A lever 58 having one end secured to the shaft 44 carries a rotatably mounted member 60 on its free end. The member 60 is slidably mounted on the end of the rod 56 and is secured thereto by an adjustment nut 62. A coil spring 64 is compressed between the member 60 and a flange 66 formed on the rod 56. The spring 64 maintains the member 60 adjacent the nut 62, which provides a means for adjusting the

throttle valves

40 and 42 with respect to one another. A third lever 68 has one end secured to the shaft 46 and a pin 70 disposed on its free end. A coil tension spring 72 has one end secured around the pin 70 and the other end secured to the outer surface of housing 34 by means of screw 74. As the accelerator pedal is pushed downward rotating the shaft 46 and the throttle valve 42 counterclockwise to open the valve 42, the lever 52 is rotated counterclockwise on the shaft 46 pulling the linkage rod 56 to the left, as shown in FIG. 6. Leftward movement of the linkage rod 56 results in the lever 58, the shaft 44 and throttle valve 40 being rotated clockwise, opening the valve. As the shaft 46 is rotated counterclockwise, the lever 68 is also rotated counterclockwise, tensioning the spring 72. When the accelerator pedal is released, the spring 72 contracts rotating the shaft 46 and the throttle valve 42 clockwise to their closed positions which, in turn, rotates the shaft 44 and the throttle valve 40 counterclockwise to the throttle valve s closed position.

Referring to FIGS. 1 and 2, a fuel nozzle assembly 76 is disposed between and in parallel with the

air inlets

36 and 38.

The fuel nozzle 76, the detailed construction of which will be described, includes a fuel outlet 78 disposed immediately above the mixing chamber for spraying a finely atomized spray of metered fuel into the mixing chamber, as indicated by the lines 80.

As the throttle valves and 42 are opened, air from the

air inlets

36 and 38 is inducted by the suction pressure of the intake manifold 20 into

air channels

82 and 84 respectively, of the mixing chamber 30, as shown in FIG. 5. The beginning of the channel 82 is formed by an outer wall 86, a backwall 87 and an inner wall 88. The inner wall 88 extends upward from the outer periphery of the outlet 28 of the mixing chamber 30 and slopes downward toward the, outlet 28 as the channel 82 curves counterclockwise around the outlet 28 to the channel outlet 89, where the wall 88 terminates. The beginning of the channel 84 is formed by an outer wall 90, a backwall 91 and an inner wall 92. The inner wall 92 extends upwardly from the outer periphery of the outlet 28 and slopes downward toward the outlet 28 as the channel 84 curves counterclockwise around the outlet 28 to the channel outlet 93, where the wall 92 terminates.

The suction pressure of the manifold inducts the air in the

channels

82 and 84 in a counterclockwise direction around the outlet 28. as illustrated in FIG. 5 by arrows 94 and 96, toward the central outlet 28 of the mixing chamber 30. The air tangentially enters the central outlet 28 where it whirls the fuel sprayed from the nozzle 76 so as to diffuse the sprayed fuel and mix it evenly with the air. The mixture then swirls axially through the outlet 28 and into the central chamber 22 of the exhaust manifold 20. As the fuel-air mixture moves through opening 26 in the exhaust manifold 20, it engages a surface 98 of a manifold wall 100. Fins 102 are formed on the opposite side of the wall and disposed in portions of the engine exhaust manifold 104, which carry hot engine exhaust gases therethrough for heating the wall 100 and the surface 98. The, heating of the fuel-air mixture from its contact with the heated surface 98 aids in the vaporization of the fuel. The central location of the chamber 22 ensures an even distribution of the charge to the individual cylinders.

Fuel to the fuel nozzle 76 is metered through a pair of variable-orifice valves shown in FIGS. 6 and 7. Fuel from a main fuel tank 106 is delivered through an inlet pipe 108 by the action of a fuel pump 110 into a fuel chamber 112. The flow of fuel from the tank 106 into the fuel chamber 112 is controlled by a variable-orifice valve assembly 114. The valve assembly 114 includes a shaft 1 16 that is closely fitted and axially movable in a bore 118, which is disposed between the opening from the conduit 108 and the fuel chamber 112. One end of the shaft 116 is secured to a diaphragm assembly 120, which is disposed in a housing 122 secured to the air inlet housing 34. The diaphragm assembly forms one wall of a control chamber 124. A coil spring 126 disposed in the chamber 124 is compressed between the side of the diaphragm assembly 120 opposite from the shaft 116 and a conically shaped member 128, which is disposed in the chamber 124 and slidably mounted over an annular boss 129 formed in the inside of the housing 122. A pin 130 threaded into the housing 122 through the center of the boss 129 has its inner end 132 engaging the inner surface of the member 128, providing adjustment therefor. The coil spring 126 urges the diaphragm assembly 120 and the piston 116 toward the right, as viewed in FIG. 7. The chamber 124 is subjected to intake manifold pressure introduced through a passage 134 formed through the

housings

32 and 34. A chamber 136 formed on the inner shaft side of the diaphragm assembly 120 is opened to atmosphere through a conduit 138, as shown in FIGS. 6 and 7.

The shaft 116 is fonned with a smaller diameter cylindrical portion 140 which intersects the opening of the conduit 108 to the bore 118 to regulate fuel flow from the conduit 108 into the fuel chamber 112. As the piston 116 is moved to the left, as viewed in FIG. 7, the smaller diameter portion is moved out of alignment with the opening of the conduit 108, thereby narrowing the passage and restricting the supply of fuel from the conduit 108 to the fuel chamber 112. The free inner end 142 of the shaft 116 is conically shaped and intersects an outlet passage 144 leading from the fuel chamber 112 to a conduit 146, which empties into a small receiving chamber 147 with an outlet 151 emptying into the fuel tank 106. As the shaft 116 is moved to the left, as viewed in FIG. 7, the effective area of the orifice formed by the conical free end 142 and the passage 144 increases, allowing more fuel from fuel chamber 112 to flow back into the fuel tank 106 through the conduit 146. Therefore, as the piston 116 moves to the left as viewed in FIG. 7, less fuel flows into the fuel chamber 112 around the Shaft portion 140 and more fuel returns to the tank 106 through the conduit 146, decreasing the fuel pressure in the fuel chamber 112. As the shaft 116 moves to the right, more fuel flows into the fuel chamber 112 and less fuel flows through conduit 144 and back to the tank 106, thereby increasing the fuel pressure in the fuel chamber 112. As the

throttle valves

40 and 42 are opened calling for more engine power and speed, airflow into the intake manifold increases, causing the manifold pressure behind the diaphragm assembly 120 to increase, allowing the spring 126 to push the diaphragm assembly 1201 and the piston 116 to the right, thus increasing the fuel pressure in the fuel chamber 112, which increases the fuel supply to the engine through the nozzle assembly 76, as will be described.

Referring to FIGS. 6 and 7, the fuel chamber 112 is formed with a boss 146 having a fuel outlet orifice 149. A variable-orifice piston 151) is closely fitted in and axially movable in a sleeve 152 that is secured in a chamber 154. The sleeve 152 has an inlet orifice 155 registering with the outlet orifice 149. The piston 1511 is formed with a tapered groove 166, which intersects the orifice 149 for passing fuel from the fuel chamber 112 into an accumulator chamber 166 which forms a part of the chamber 154. A conduit 170 leading from the accumulator chamber 168 connects to a conduit 172, as shown in FIG. 1, which leads to the fuel nozzle assembly 76 for providing liquid fuel thereto. The piston 150 forms a variable orifice 174 between the left end of the sleeve 152 and the tapered groove 166 for metering the fuel. As the piston 1511 moves to .the left, as viewed in FIG. 7, the orifice 174 increases due to the taper of the groove 166, thereby increasing the metering area, allowing more fuel to flow from the fuel chamber 112 to the conduit 1711 and to the fuel nozzle assembly 76. The piston 150 is formed with an annular recess 176 and has a quad-ring 178 disposed therein to prevent leakage of fuel around the piston 150. The piston 150 has its end opposite the accumulator chamber 168 connected to one end of a lever 156 by means of pin 158. The other end of the lever 156 is pivotally mounted on a pin 160 that is secured to one end of a lever 162, which is secured to a rotatably mounted shaft 164. Thus, as the shaft 164 is rotated clockwise, as viewed in FIG. 7, the lever 162 is rotated clockwise pushing the lever 156 to the left, thereby pushing the piston 1511 to the left and increasing the opening of the orifice 174, allowing more fuel to flow from the chamber 112 to the fuel nozzle 76.

Referring to FIG. 6, the outer end of the shaft 164 has one end of a lever 178 secured thereto and a member 180 is rotatably mounted to the other end of the lever 178. The rotatably mounted member 180 is slidably mounted on one end of a linkage rod 162 and held thereon by an adjustment nut 184. A coil spring 186 is mounted around the linkage rod 182 and compressed between a flange 188 formed on the linkage rod 182 and the member 1811, thereby maintaining the member 186 adjacent the nut 184. The other end of the linkage rod 182 is pivotally mounted on the lever 52. As the accelerator pedal (not shown) is pushed the lever 46 rotates the shaft 46 and the throttle valve 42 counterclockwise opening the air inlet 36. The lever 52 is also rotated counterclockwise pulling the linkage rod 56 to the left, as viewed in FIG. 6, rotating the shaft 44 and the throttle valve 40 clockwise opening the air inlet 36. Simultaneously the linkage rod 162 is pulled to the left by the rotation of the lever 52, rotating the lever 178 and the shaft 164 clockwise, as viewed in FIG. 6. The clockwise rotation of the shaft 164, as viewed in FIG. 7, rotates the lever 162 clockwise pushing the lever 156 and the piston 150 to the left. The movement of piston 150 to the left increases the orifice opening 174, thus allowing more fuel to flow from the fuel chamber 112 to the fuel nozzle assembly '76.

The above arrangement provides a pressure-regulating means formed by the smaller diameter section 114 of the shaft 116 intersecting the opening from the inlet conduit 108 and operating in conjunction with the conical end 142 that is disposed in the outlet passage 144 for varying the fuel pressure in the fuel chamber 112. As the throttle valves 41) and 42 are opened allowing more air to be inducted into the engine intake manifold, the intake manifold pressure increases, operating the shaft 116 to increase the fuel pressure in the chamber 112. The increased fuel pressure in the chamber 112 results in higher pressure fuel flowing through the tapered groove 166 to the fuel nozzle assembly 76. The opening of the

throttle valves

40 and 42 also, through the direct linkage already described, pushes the piston to the left, as viewed in FIG. 7, resulting in an increase in the opening of the orifice 174, allowing more fuel to flow to the nozzle assembly 76, which injects a spray of fuel into the mixing chamber 311. Thus, as the throttle valves are opened the fuel pressure in the chamber is increased to provide higher fuel pressure and the orifice 174 is increased to provide more fuel flow to the engine.

At engine idling speed, the minimum fuel flow required is provided by having the pressure-varying portion 1411 of the shaft 116 very slightly open, and the metering valve orifice 174 also slightly open such that the correct quantity of fuel is supplied to the nozzle assembly 76 for normal engine idling. The screw 1311 threaded into the housing 122 is provided for adjusting the initial position of the valve assembly 114, which adjusts the pressure in the fuel chamber 112. Inward turning of the screw 131D operates to increase the pressure in the fuel chamber 112. The nut 184 on the end of the linkage rod 182, as shown in FIG. 6, is used to adjust the idle position of the piston 1511 which adjusts the idle opening of the orifice 174. As the nut 164 is turned further on the linkage 182, the shaft 164 is turned clockwise resulting in the piston being pushed to the left, as shown in FIG. 7, resulting in increasing the opening of the orifice 174, allowing more fuel to flow to the nozzle 76. With the

throttle valves

40 and 42 closed, air for idling is provided through an adjustable air inlet 1% formed in the housing 34, as shown in FIGS. 1 and 2. An idle air adjustment screw 1911 is provided for adjusting the amount of air which may enter through the inlet 168.

It is to be noted that when the throttle valves 41) and 42 are opened quickly allowing air to rush into the intake manifold for quick acceleration, the piston 150 is quickly moved to the left, as viewed in FIG. 7. The leftward movement of the piston 150 forces the free end of the piston into the accumulator chamber 166, immediately displacing a portion of the fuel therein. The displaced fuel passes through the outlet conduit to the nozzle assembly 76 positively providing the greater quantity of fuel needed to mix with the sudden rush of air.

Furthermore, the valve assembly 114 is automatically selfcompensating for changes in the barometric pressure. When the barometric pressure decreases, less air is pushed into the intake manifold, resulting in a decrease in the intake manifold pressure. With less air entering the intake manifold, less fuel is required. The decrease in the intake manifold pressure decreases the pressure in the chamber 124, pulling the shaft 116 to the left, as viewed in FIG. 7, decreasing the fuel pressure in the fuel chamber 112. The decrease in the fuel pressure results in less fuel being supplied to the nozzle assembly 76. Thus, less fuel is supplied to mix with the decreased supply of air.

Finally, it is to be noted that the valve assembly 114 automatically increases the supply of fuel for torque backup. At a fixed setting of the throttle valves 411 and 42 and the piston 150, the intake manifold pressure increases if the engine speed is decreased due to an added load, such as climbing a hill. When the engine speed decreases, the intake manifold pressure increases, resulting in the piston 116 being moved to the right increasing the fuel pressure in the chamber 112. The increased pressure results in more fuel being supplied to the engine to aid in pulling the increased load.

Referring to FIG. 7, a variable idler stop lever 192 is provided to give a higher idling speed during engine warmup. The lever 192 has one end pivotally mounted in a fulcrum slot 194 formed in the housing 32. The other end of the lever 192 is pivotally mounted by means of pin. 1116 on a diaphragm assembly 198, disposed in a housing 21111 which is secured to the housing 32 by any convenient means. A coil spring 202 disposed in a chamber 204 formed between the housing 200 and the diaphragm assembly 194 engages the diaphragm as sembly 196 to urge the assembly toward the left, as viewed in FIG. 7. As the diaphragm assembly 19 8 is moved back and forth, the lever 192 is pivoted about the: end which is engaged in the slot 194. The chamber 204 is connected to the intake manifold pressure by means of a passage 206, whereas a chamber 208 on the other side of the diaphragm assembly 198 is subjected to atmospheric pressure. When the internal combustion engine is first started, the intake manifold pressure is relatively high due to the slow speed of the engine resulting from high viscosity of the cold lubrication oil and the increased friction between the cold engine parts. The high intake manifold pressure results in a high'pressure in chamber 204 allowing the spring 202 to push the diaphragm assembly 198 to the left, as viewed in FIG. 7, rotating the lever 192 counterclockwise about groove 194 into engagement with the lever 162 to push the lever 156 and piston 150 to the left. The leftward movement of the piston 150 increases the fuel supply to the nozzle assembly 76, increasing the speed of the engine. Simultaneously with the opening of the orifice 174, the linkage between the shaft 164 and the

throttle valves

40 and 42 opens the valves, allowing more air into the engine to increase the'idle speed. Therefore, the idle speed lever 192 must exert enough force to not only open the orifice 174 but also open the

throttle valves

40 and 42. This force is provided by utilizing better than a two to one advantage in the lever 192.

As the engine warms up, friction is reduced and the engine speed increases which decreases intake manifold pressure. The decreased pressure results in the atmospheric pressure on the diaphragm assembly 198 compressing the opposing spring 202, moving the lever 192 out of engagement with the lever 162, allowing the throttle valves and the piston 150 to move to a slower idling position.

Referring to FIGS. 1, 2 and 8 through 12, the fuel spray nozzle assembly 76 is formed with a pair of

apertures

210 and 212 formed in an annular flange 213 on tubular body 218. A pair of screws 214 are inserted through

apertures

210 and 212 for securing the nozzle assembly to the housing 34. The nozzle assembly 76 includes a threaded opening 216 formed in one end of the body 218 for connection to the conduit 172 for receiving metered fuel therefrom. The assembly 76 is preferably formed in three parts, a tubular body 218, a fuel-atomizing tip 220 and a tubular, shell 222. Fuel from the inlet 216 flows down an elongated passage 224 fonned on the axis of elongation through the body 218. The passage 224 is generally rectangular in cross section, as is indicated in FIG. 12, and narrows slightly at a point approximately halfway down the body 218. The passage 224 has two side outlets 226 and 228 opening into an annular chamber 234 formed between the body 218 and the tip 220. The end of the passage 224 is blocked by a U-shape tab 230, which is secured to or integral with the end of the body 218, thereby forcing the fuel flowing through the passage 224 to exit through the side opening 226 and 228. The outlet end of the body 218 is formed with an annular recess 232 for receiving the tubular fuel-atomizing tip 220, which is pressed over the outlet end of the body 218. When the fuel exits through the outlets 226 and 228, it is received in the chamber 234. As shown in FIG. 11C, the tip 220 is formed with a plurality of inwardly extending flanges 236 which impart a whirling action to the liquid fuel flowing through the chamber 234, such that as the fuel exits through the outlet opening 238 formed in the tip 220 it is whirling at a high rate of speed.

The body 218 is formed with a second annular recess 240 provided in surface 241 of the flange 213 for receiving one end of the tubular shell 222. Air or gas from a source to be described enters through a passageway 242, as shown in FIGS. 1 and 2, into a pair of openings 244 formed in the surface 241 of the flange 213. From the openings 244 the air or gas passes into an annulus 246 formed between the tubular body 218 and the tubular shell 222. The forward end of the tubular shell 222 is formed with a plurality of internal flanges 248 for whirling the gas or air into the whirling fuel exiting from the outlet 238. Therefore, the whirling fuel from the outlet 238 engages the whirling gas or air from the annular space 246, thoroughly diffusing and mixing the fuel and the air or gas, the mixture being discharged through the tubular shell outlet 250 into the mixing chamber 30, thereby providing an evenly distributed fuel-air spray into the chamber 30.

The three-part construction of the nozzle assembly 76 is designed for die casting and for easy assembly by pressing the nozzle tip 220 over the tubular body 218. The tubular shell 222 is then pressed into the annular recess 240 of the tubular body 218 with the flanges 248 engaging the tip 220 to maintain the tip on the tubular body 218. The nozzle assembly 76 is then inserted into the supporting structure 252, as shown in FIG. 2, with the structure 252 engaging the flange 253 of the shell 222 to retain it on the body 218. The screws 214 are then secured to the structure 252.

The annular chamber 246 between the shell 222 and the body 218 may be selectively alternatively vented to atmospheric air and hot engine exhaust gases. During highspeed operation the chamber 246 is vented to engine exhaust gases which are under pressure and hence act to more completely atomize the fuel. During low-speed operation and engine idle condition the chamber 246 is vented to atmospheric air, since oxygen from the atmosphere is needed during engine idling. Furthermore, the air satisfies the intake manifold vacuum and thus keeps it from exerting a suction on the fuel outlet 238. Thus, the fuel passage 224 is kept solidly filled with fuel.

FIGS. 1, 7, and 13 illustrate a valving system for selectively alternatively directing air and hot engine exhaust gases to the nozzle assembly 76. A valve plunger 254 comprising a diskshaped valve member 255, a stem 256 having one end secured to the member 255, and a guide member 258 positioned at the other end of the stem 256, is slidably mounted on the housing 34. Member 255 is movable between a lower position, as shown in FIG. 13, wherein it engages valve seat 260 and an upper position wherein it engages a valve seat 262. The guide member 258 is formed with an annular flange 264 which aids in maintaining the valve assembly axially aligned in the housing 34 and further engages a leaf spring 266 which is secured to the housing 34 by means of screw 268. The leaf spring 266, as shown in FIG. 7, is formed with a projection 270 for engaging the annular flange 264, maintaining the valve member 255 selectively in engagement with the valve seat 260 or the valve seat 262. From its lower position, as viewed in FIG. 7, the valve assembly 254 may be snapped upward against the valve seat 262, with the projection 270 on the leaf spring 266 engaging the lower side of the annular flange 264 to maintain the valve assembly 254 in its upper position.

When the valve member 255 is in its lower position against the valve seat 260, a passageway 310, which is connected to the engine exhaust manifold, is closed off preventing the exhaust gases from entering the passageway 242 and passing to the nozzle assembly 76. With the valve in this position the air from beneath the air cleaner is allowed to pass through opening 263 and into the conduit 242 to the nozzle assembly 76. When the valve member 255 is snapped to its upper position against the valve seat 262, air is prevented from entering the passageway 242, but exhaust gases from the passageway 310 are allowed to enter the conduit 242 and flow to the fuel nozzle 76.

The valve assembly 254 is responsive to intake manifold pressure through a pressure-responsive unit 272. The unit 272 includes a diagram assembly 274 which forms one wall of a chamber 276 that is subjected to intake manifold pressure through a passageway 278 that communicates with the engine intake manifold. A coil spring 280 disposed within the chamber 276 is compressed between the diaphragm assembly 274 and a wall 282 of the chamber 276. The diaphragm assembly 274 includes a stud 284 projecting outwardly from the assembly away from the chamber 276. An L-shaped lever 288 has the end of one of its arms pivotally secured to the stud 284 by means of a pin 286. The lever 288 is pivotally mounted to the housing 34 on pin 290.

The end of the other arm of the lever 288 is pivotally mounted to a rod 292. The other end of the rod 292 is pivotally mounted to the end of one of the arms of an L- shaped lever 294, which is pivotally mounted on a pin 296 secured to the housing 34. The other arm-of the lever 294 is pivotally secured to a block 388 by means of pin 298. The block 3118, which is slidably mounted on the housing 34, includes a flange 382 with an opening 384 formed therein for receiving shaft 256 therethrough. A coil spring 3116 positioned around the shaft 256 is disposed between the lower surface of the flange 382 and the valve member 255. A second coil spring 388 positioned around the shaft 256 is disposed between the upper surface of the flange 382 and the guide member 258.

in operation, as the diaphragm assembly 274 moves upwards in response to an increase in intake manifold pressure, the lever 288 is rotated counterclockwise about pin 290, push ing the rod 292 to the left. The leftward movement of the rod 292 rotates the lever 294 counterclockwise about pin 296, moving the slidably mounted block 380 upwards by means of pin 298. The upward movement of the block 3118 compresses the coil spring 388 exerting an increased upward force on the guide member 258 and the valve assembly 254. When the block 388 has moved upward sufficiently to compress the spring 388 enough to overcome the force of leaf spring 266 acting upon the annular flange 264, the valve assembly 254 snaps upwards, with the projection 270 engaging the bottom portion of the annular flange 264.

As the intake manifold pressure is decreased, as in engine idling operation, the diaphragm assembly 274 is pushed downward by atmospheric pressure acting on its top side, rotating the lever 288 clockwise about pin 291) resulting in the lever 294 being rotated clockwise about the pin 296, pushing the block member 388 downward. The downward movement of the block member 388 compresses the spring 306, snapping the valve assembly 254 to its downward position, thereby closing the passageway 3110 and opening the passageway 263 to admit air into the passageway 242 to be inducted into the fuel nozzle assembly 76. Thus, during engine idle condition when the intake manifold pressure is low, the nozzle assembly 76 is vented to air, which aids in the combustion process and prevents the manifold vacuum from sucking all of the fuel from the passage 224. During highspeed operation when the intake manifold pressure is high, the nozzle 76 is vented to engine exhaust gases from passageway 310, which aids in the vaporization of the fuel and materially reduces the formation of nitric oxide by the engine.

it is to be noted that the diaphragm assembly 274 is displaced from the valve assembly 254, which is subjected to hot engine exhaust gases. Since the diaphragm assembly 274 would be damaged by the heat from the hot gases, the displacement of the diaphragm from the valve assembly 254 will substantially lengthen the life of the diaphragm assembly 274.

It may be noted that during engine idling condition, air may pass through the opening 263 and into conduit 188, as shown in F108. 1, 2, and 7. The adjustment screw 1191) is provided therein to regulate the idle setting.

Referring to P16. 11, a sealed water tank 312 having a filler cap 314 is provided with a conduit 3116 connected to the passageway 242 for communicating engine exhaust gases to the tank 312 to pressurize the tank. A second conduit 318 is connected between the bottom of the water tank 312 and an inlet port 328 formed in housing 34 above throttle valve 48 for injecting water from the tank 312 to the air inlet 36. An adjustment screw 322 is threaded into the housing 34 to adjust the opening for the introduction of the water spray. The conduit 242 is open to engine exhaust gases during high-speed operation, pressurizing the tank 312 to force a water spray into the air inlet 36. During engine idle operation, the conduit 242 is open to atmosphere air, thus the tank 3112 is not pressun'zed during engine idle and no water is sprayed into the air inlet 36. The introduction of humidity into the engine cools the combustion process to prevent the formation of nitric oxide.

Referring to FIGS. 11, 6, and 114 through 17, a chamber 324 for venting the crankcase fumes is formed in the housing 32 for the reception of adhesion plates 326 secured to a cover 328. The cover 328 is secured over the chamber 324 by means of a bolt 338. The chamber 324 is communicated with the engine crankcase by means of conduits 332through opening 333 for receiving engine crankcase fumes therefrom. The crankcase fumes are inducted into one end of the chamber 324 from the conduits 332 and weave back and forth between the plates 326 before exiting through an opening 334 formed in the cover 328. The cover 328 is formed with a domed side 335 having a lip 336 extending over the opening 334. Fresh air is continually supplied to die engine crankcase through a conduit 335, as shown in FIG. 18, communicating from beneath the carburetor air filter (not shown) and the crankcase.

As illustrated in FlGS. 6 and 17, during engine idling a vacuum is created in the intake manifold which is communicated to the air inlet 38 beneath the closed throttle valve 42. The vacuum is transferred to the opening 334 through a small hole 338 formed in the throttle valve 42, by means of the lip 336, which extends over the opening 334 and the hole 338 and engages the closed valve. The vacuum draws the crankcase fumes from the crankcase into the chamber 324 where they are delivered to the engine cylinders for burning. The adhesion plates 326 cause the oil or other particles which may have been expelled from the crankcase with the funies to either adhere to the plates 326 or drop downward and thereby find their way back to the crankcase through opening 333. During high-speed operation, the throttle valve 42 being open, the intake manifold vacuum is communicated directly to the outlet 334 to draw the crankcase fumes therefrom.

The inner lower portion 340 of the cover 328 forms a portion of the wall of the air inlet 38. The throttle valve 42 is preferably formed with a flange 358, which encircles the outer edge of the lip 336 when the valve 42 is in the closed position, aiding in communicating the vacuum to the chamber 324.

A fuel shutoff valve 360 as illustrated in FIGS. 1, 7, and 14, may be provided for manually shutting off the fuel when the engine has become flooded. The valve 360 includes an elongated needle valve 362 slidably mounted in a sleeve 364, which is threaded into the housing 32. The valve 362 has a pointed tip disposed in the fuel chamber 112 for insertion into the outlet orifice 149 for stopping the flow of fuel from the fuel chamber 112. The valve 362 has a pair of quad-rings 368 positioned therearound within the sleeve 3 to prevent leakage of fuel from the chamber 112.

The valve 362 is actuated by a lever 378 that is pivotably mounted on the housing 32 by means of a pin 372. The lever 378 includes a slot 374 that engages a pin 376 secured to the outer end of the valve 362. A push-pull rod 378 has one end pivotally mounted to the free end of the lever 378 for actuation thereof and preferably has its other end secured to a knob (not shown) supported on the automobile dashboard. Pushpull movement of the knob results in the lever 378 rotating the lever 378 about the pin 372. The rotation of the lever 370 is transferred into longitudinal movement of the valve 362 for opening and closing the fuel outlet orifice 149.

ll claim:

1. In an internal combustion engine having an intake manifold adapted to distribute fuel-air mixture to engine cylinders, a fuelair induction system comprising:

air induction means having an air outlet;

fuel delivery means having a fuel discharge outlet;

a mixing chamber having an inlet end. disposed downstream and adjacent said induction and said delivery means outlets and an outlet discharging directly into said intake manifold, said mixing chamber having means downstream of said fuel discharge outlet eonstnucted and arranged to direct air from said induction means air outlet tangentially and inwardly to whirl and thereby substantially uniformly mix the air and fuel simultaneously entering the inlet end, thereby to assist atomization of the fuel prior to discharge of the air and fuel into said intake manifold from which the mixture is distributed,

said air induction means comprising a pair of substantially parallel linear air ducts, each of said ducts having a throttle valve disposed therein, and said fuel delivery means includes a fuel nozzle disposed between said air ducts and arranged to discharge a metered quantity of fuel in only substantially the same general direction as the air discharging from said air ducts, and

said mixing chamber including an open linear passage having a downstream end opening directly to said intake manifold and an upstream end disposed in line with the path of the discharged fuel from said fuel nozzle, said mixing chamber having a pair of channels respectively having upstream ends disposed in line with the path of the inducted air from said air ducts, said channels encircling and open to said linear passage for whirling the inducted air around said linear passage.

2. In an internal combustion engine having an intake manifold adapted to distribute fuel-air mixture to engine cylinders, a fuel-air induction system comprising:

air induction means having an air outlet;

fuel delivery means having a fuel discharge outlet;

a mixing chamber having an inlet end disposed downstream and adjacent said induction and said delivery means outlets and an outlet discharging directly into said intake manifold, said mixing chamber having means downstream of said fuel discharge outlet constructed and arranged to direct air from said induction means air outlet tangentially and inwardly to whirl and thereby substantially uniformly mix the air and fuel simultaneously entering the inlet end, thereby to assist atomization of the fuel prior to discharge of the air and fuel into said intake manifold from which the mixture is distributed,

means comprising an actuated element for metering fuel to said fuel delivery means; and

an idle stop mechanism responsive to engine manifold pressure and having an automatically adjustable element associated with said fuel-metering means and engageable with said actuated element only when said element moves toward a position reducing fuel delivery for varying the engine idle setting of said metering means.

3. In an internal combustion engine having an intake manifold and a housing having air induction means and a fuel metering and distribution means including an actuated element, an idle stop mechanism comprising;

a manifold pressure-actuated element;

an idle stop lever having a first point pivotally supported by said housing and a second point pivotally secured to said manifold pressure actuated element for rotating said lever about said first point, a portion of said lever intermediate said first and second points engageable with said fuel metering means actuated element only when same moves toward a position reducing fuel delivery for varying the idle setting of said fuel-metering means.

4. In an intemal combustion engine having an intake manifold adapted to distribute fuel-air mixture to engine cylinders, a fuel-air induction system comprising:

air induction means having an air outlet;

fuel delivery means having a fuel discharge outlet;

said mixing chamber having a centrally located linear passage and at least one surrounding helical passage open throu out its length to said linear passage, said fue delivery means Including a nozzle In ecting fuel into the upstream end of said linear passage and being in line therewith, said air induction means including an air duct directing air into the upstream end of said helical passage and in line therewith, and

said passages opening at their downstream ends directly into said intake manifold.

5. In an internal combustion engine having an intake manifold adapted to distribute fuel-air mixture to the engine cylinders, a fuel-air induction system comprising:

air induction means;

fuel delivery means;

a mixing chamber disposed downstream of said induction means and said delivery means, said chamber including a centrally located outlet port communicating with said intake manifold and a pair of channels encircling a portion of said outlet port for whirling the air and fuel prior to the induction of same into said intake manifold and thereby substantially uniformly mix the air and fuel and assist atomization of the fuel, prior to the induction of said mixture into said intake manifold from which said mixture is distributed;

said air induction means comprising a pair of substantially parallel inlets, each of said inlets including a throttle valve disposed therein, said fuel delivery means including a fuel nozzle disposed between said air inlets and arranged to direct a metered quantity of fuel substantially parallel with the incoming air from said air inlets;

said mixing chamber outlet port being disposed in the path of the discharged fuel from said fuel nozzle, the pair of channels of said chamber each having its beginning disposed in the path of the inducted air from one of said air inlets; and

said fuel delivery means including a fuel nozzle assembly comprising a tubular body having a fuel inlet and outlet, a fuel-atomizing tip surrounding the portion of said tubular body containing said fuel outlet for receiving fuel therefrom, said tip having a fuel outlet port and a plurality of inwardly extending flanges for imparting a whirling motion to the fuel before directing it through said fuel outlet port, and a tubular shell surrounding the tip and a portion of said tubular body for forming a space therebetween for the passage of gases, said shell having a discharge port spaced from said fuel outlet port and a plurality of inwardly extending flanges for imparting a whirling motion to the gases before the gases contact the fuel from the said outlet port.

patent 201 Dated 18 January 1972 Inventor(s) Carl High It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

IN THE SPECIFICATION:

Col. 2. line 46, after "taken" insert --substantially-- line 52, delete "a front" and insert therefore -an elevationaland'delete "shown in" and insert therefore--as seen from the bottom side of- Col. 3, line 49, insert --40- before the period line 52, insert after "contracts" Col. 4, line 5, after "manifold" insert --20- line ll, after "fuel" insert -80-- line 13, change "exhaust" to -intakeline 14, change "exhaust" to -intake line 23, after "individual" insert -engineand after "cylinders" insert -(not shown) through the intake runners 24- line 45, change "piston" to shaft line 55, change "piston" to -shaft line 56, after "portion" insert -l40-- Col. 5, line 5, change "piston" to shaft-- line 46, after "and" insert is and change "188" to --l89-- line 66, change "114" to -l40-- Col. 6, line 24, after "piston" insert --l50- FORM PO-105O (10-69) USCOMM-DC 60376-P59 u.s. GOVERNMENT PRINTING OFFICE I989 0-366-334 3,635,201 January 18, 1972 Col. 6, line 60, change "piston" to s,haft

Col. 7, line 45, after "218" insert as indicated in Fig. ll-

line 50, change "opening" to -openings-- Col. 8, line 62, change "diagram" to --diaphragm- Signed and sealed this 27th day of June 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTISCHALK Attesting Officer Commissioner of Patents

Claims

1. In an internal combustion engine having an intake manifold adapted to distribute fuel-air mixture to engine cylinders, a fuel-air induction system comprising: air induction means having an air outlet; fuel delivery means having a fuel discharge outlet; a mixing chamber having an inlet end disposed downstream and adjacent said induction and said delivery means outlets and an outlet discharging directly into said intake manifold, said mixing chamber having means downstream of said fuel discharge outlet constructed and arranged to direct air from said induction means air outlet tangentially and inwardly to whirl and thereby substantially uniformly mix the air and fuel simultaneously entering the inlet end, thereby to assist atomization of the fuel prior to discharge of the air and fuel into said intake manifold from which the mixture is distributed, said air inductIon means comprising a pair of substantially parallel linear air ducts, each of said ducts having a throttle valve disposed therein, and said fuel delivery means includes a fuel nozzle disposed between said air ducts and arranged to discharge a metered quantity of fuel in only substantially the same general direction as the air discharging from said air ducts, and said mixing chamber including an open linear passage having a downstream end opening directly to said intake manifold and an upstream end disposed in line with the path of the discharged fuel from said fuel nozzle, said mixing chamber having a pair of channels respectively having upstream ends disposed in line with the path of the inducted air from said air ducts, said channels encircling and open to said linear passage for whirling the inducted air around said linear passage.

2. In an internal combustion engine having an intake manifold adapted to distribute fuel-air mixture to engine cylinders, a fuel-air induction system comprising: air induction means having an air outlet; fuel delivery means having a fuel discharge outlet; a mixing chamber having an inlet end disposed downstream and adjacent said induction and said delivery means outlets and an outlet discharging directly into said intake manifold, said mixing chamber having means downstream of said fuel discharge outlet constructed and arranged to direct air from said induction means air outlet tangentially and inwardly to whirl and thereby substantially uniformly mix the air and fuel simultaneously entering the inlet end, thereby to assist atomization of the fuel prior to discharge of the air and fuel into said intake manifold from which the mixture is distributed, means comprising an actuated element for metering fuel to said fuel delivery means; and an idle stop mechanism responsive to engine manifold pressure and having an automatically adjustable element associated with said fuel-metering means and engageable with said actuated element only when said element moves toward a position reducing fuel delivery for varying the engine idle setting of said metering means.

3. In an internal combustion engine having an intake manifold and a housing having air induction means and a fuel metering and distribution means including an actuated element, an idle stop mechanism comprising; a manifold pressure-actuated element; an idle stop lever having a first point pivotally supported by said housing and a second point pivotally secured to said manifold pressure actuated element for rotating said lever about said first point, a portion of said lever intermediate said first and second points engageable with said fuel metering means actuated element only when same moves toward a position reducing fuel delivery for varying the idle setting of said fuel-metering means.

4. In an internal combustion engine having an intake manifold adapted to distribute fuel-air mixture to engine cylinders, a fuel-air induction system comprising: air induction means having an air outlet; fuel delivery means having a fuel discharge outlet; a mixing chamber having an inlet end disposed downstream and adjacent said induction and said delivery means outlets and an outlet discharging directly into said intake manifold, said mixing chamber having means downstream of said fuel discharge outlet constructed and arranged to direct air from said induction means air outlet tangentially and inwardly to whirl and thereby substantially uniformly mix the air and fuel simultaneously entering the inlet end, thereby to assist atomization of the fuel prior to discharge of the air and fuel into said intake manifold from which the mixture is distributed, said mixing chamber having a centrally located linear passage and at least one surrounding helical passage open throughout its length to said linear passage, said fuel delivery means including a nozzle injecting fuel into the upstream end of said linear passage and being in line therewith, said air induction means including an air duct directing air into the upstream end of said helical passage and in line therewith, and said passages opening at their downstream ends directly into said intake manifold.

5. In an internal combustion engine having an intake manifold adapted to distribute fuel-air mixture to the engine cylinders, a fuel-air induction system comprising: air induction means; fuel delivery means; a mixing chamber disposed downstream of said induction means and said delivery means, said chamber including a centrally located outlet port communicating with said intake manifold and a pair of channels encircling a portion of said outlet port for whirling the air and fuel prior to the induction of same into said intake manifold and thereby substantially uniformly mix the air and fuel and assist atomization of the fuel, prior to the induction of said mixture into said intake manifold from which said mixture is distributed; said air induction means comprising a pair of substantially parallel inlets, each of said inlets including a throttle valve disposed therein, said fuel delivery means including a fuel nozzle disposed between said air inlets and arranged to direct a metered quantity of fuel substantially parallel with the incoming air from said air inlets; said mixing chamber outlet port being disposed in the path of the discharged fuel from said fuel nozzle, the pair of channels of said chamber each having its beginning disposed in the path of the inducted air from one of said air inlets; and said fuel delivery means including a fuel nozzle assembly comprising a tubular body having a fuel inlet and outlet, a fuel-atomizing tip surrounding the portion of said tubular body containing said fuel outlet for receiving fuel therefrom, said tip having a fuel outlet port and a plurality of inwardly extending flanges for imparting a whirling motion to the fuel before directing it through said fuel outlet port, and a tubular shell surrounding the tip and a portion of said tubular body for forming a space therebetween for the passage of gases, said shell having a discharge port spaced from said fuel outlet port and a plurality of inwardly extending flanges for imparting a whirling motion to the gases before the gases contact the fuel from the said outlet port.