US3043574A

US3043574A - Fuel supply system for engine

Info

Publication number: US3043574A
Application number: US850373A
Authority: US
Inventors: William E Leibing
Original assignee: Individual
Current assignee: Individual
Priority date: 1959-11-02
Filing date: 1959-11-02
Publication date: 1962-07-10
Anticipated expiration: 1979-07-10

Description

July 10, 1962 w. E. LElBlNG 3,043,574

FUEL SUPPLY SYSTEM FOR ENGINE Filed Nov. 2. 1959 5 Sheets-Sheet 1 INVENTOR.

6 WILLIAM E. LEIBING BY FIG. 2 MAM/4 ATTORNEY y 1962 w. E. LEI'BING 3,043,574

FUEL SUPPLY SYSTEM FOR ENGINE v Filed Nov. 2. 1959 1 3 Sheets-Sheet 2 IN V EN TOR.

WILLIAM E. LEIBING mawfl;

ATTORNEY July 10, 1962 w. E, LElBlNG 3,043,574

FUEL SUPPLY SYSTEM FOR ENGINE Filed Nov. 2, 1959 3 Sheets-Sheet 3 FIG. 5

F G INVEN TOR.

WILLIAM E. LEIBING By 2224. v

ATTORNEY United States.

The present invention relates to fuel systems and more particularly to fuel systems for internal combustion engines.

In various programs to overcome air pollution in large metropolitan areas in this country, an effort is being made to eliminate or materially reduce the amount of hydrocarbons emitted from automobiles, trucks and buses Most of the attention in these programs has been directed to the elimination of the hydrocarbons from the exhausts of operating vehicles and includes the use of de vices for shutting ed the idling system during deceleration from high speeds and removing the unburned fuel from the exhaust with an after-burner. These devices and methods have been only partially successful and have failed to eliminate one principal source of unburned fuel'entering the atmosphere. When an automobile, bus or truck is shut off after having been run until the engine and manifold are hot and the carburetor is warm, liquid fuel in the float chamber, accelerating pump, and main and idling jets vaporizes and passes through the air horn and air filter and through the open valves of the engine cylinders and exhaust pipe into the atmosphere. The amount of fuel entering the atmosphere for each time the engine is stopped may be as much as several ounces, and the vehicle is often started and stopped a number of times per day. Thus it is seen that in the period of one day a large amount of hydrocarbons is emitted into the atmosphere from this one source alone and in a manner not touched by any of the devices or mechanisms on the market. Further, the conventional and Widely used float type carburetors can not be adapted or modified readily or conveniently to such mechanisms without seriously interfering with the normal operation and/or unduly complicating their construction. It is therefore one of the principal objects of the present invention to provide a system which eliminates or minimizes the emission of fuel vapors into the atmosphere from a recently shut off internal combustion engine and which can be installed on the conventional engine without making any substantial changes or modifications in the engine or engine controls.

Still another object of the invention is to provide a float type carburetor, the outlets of which can be effectively closed after the engine has been shut off to prevent any fuel vapors or liquid fuel from passing into the induction passage or directly into the atmosphere.

A further object is to provide a carburetor which can be accurately regulated and controlled to supply the optimum fuel-air mixture under all normal operating conditions,'and which is compact and capable of being installed in limited space beneath the hood without interfering with the conventional arrangement of parts and accessories on the engine.

Another object of the invention is to provide a fuel atent G system for automobiles, trucks, tractors and buses which I Patented July 10, 1962 ice FIGURE 3 is a vertical cross sectional view of the carburetor taken on line 3-3 of FIGURE 2;

FIGURE 4.is a vertical cross sectional view of the carburetor taken on line 4 4 of FIGURE 1;

FIGURE 5 is a vertical cross sectional view of the carburetor taken on line 5-5 of FIGURE 2;

FIGURE 6 is a vertical cross sectional view of the carburetor taken on line 6-6 of FIGURE 2; and

FIGURE 7 is a schematic view of a vehicle fuel system showing the fuel tank, carburetor and connecting lines.

Referring more specifically to the drawings, numeral 19 designates generally the present carburetor, 12 the walls forming the induction passage 14, 16 a fuel bowl, 2d a solenoid for closing the carburetor discharge ports, and 22 a flange connected to the discharge end of the induction passage and adapted to be mounted on the intake manifold of the engine and secured thereto by bolts extending through

holes

24 and 25. The size and shape of the carburetor and fixtures therefor, including the size and shape of flange 22, may vary from one make and size engine to another, and these variations and modifications may be made without departing from the scope of the present invention.

Induction passage 14 includes intake and

discharge openings

26 and 28, a venturi 30, and a throttle 32 rotatably mounted in the throat of the venturi on a shaft 34, the shaft being rotated by an accelerating pedal or lever through a linkage (not shown) connected to a lever 36 on one end of shaft 34. The air horn which defines the intake opening of the induction passage would normally have an air cleaner (not shown) secured thereto. Throttle 32 contains the main discharge nozzle consisting of a fuel discharge tube 40 which is disposed on the engine side of the throttle when the throttle is closed, as shown in FIGURE 2, and which projects outwardly to one side when the throttle is wide open. Theend of tube 40 is beveled with the longest side on the upstream side or top of the throttle to improve the distribution of the fuel in the air stream when the throttle is open. The tube is connected to the fuel metering system of the carburetor through a longitudinal passage 42 in the center of shaft 34 and is supplied with air for atomization of the fuel through a tube 44 projecting outwardly from the throttle directly opposite discharge tube 40.

The fuel is supplied to the carburetor from the fuel tank 46 and pump 47 through a fuel line 48 which discharges into the float chamber 50 through valve 52. The valve element 54 is moved to and from its seat 56 by a float 58 mounted on arm 60 which is pivoted on a pin 62supported by the sides of the float chamber. The float may be constructed of any suitable material, either of cork or of metal, in the form of a hollow shell and is semicircular in shape to conform generally with the internal shape of the float chamber side walls. The fuel level in the float chamber is maintained at approximately the position indicated by broken line 61. The upper portion of the float chamber is vented to the air intake of the carburetor, i.e. to the atmosphere, through a passage consisting of a downwardly extending tube 63 opening into the upper portion of the float chamber, and a tube 64 connecting the upper end of tube 63 with the intake of the carburetor and preferably projecting thereinto as shown at numeral 66. Tube 63 is closed by a valve 68 seating on the lower end thereof, as will be more fully explained hereinafter.

The float chamber is connected to passage 42 by a fuel well 70 in a cylindrically shaped housing 72 between the fuel bowl and the induction passage, said housing preferably being formed integrally with the walls of the induction passage'and' having the fuel bowl secured thereto by a plurality of screws 74. A port 76 connects the fuel well 3 with the float chamber at the bottom thereof and is con' trolled by a valve 78 which moves in and out of port 76 in response to changes in manifold vacuum transmitted through a tube 80 to a pressure responsive unit 82. Unit 82 consists of a housing 84 secured to the lower part of the fuel bowl and having two chambers 86 and 83 separated by a flexible diaphragm 90, the latter chamber being connected by a passage 92 to the floatchamber and hence containing fuel during the operation of the carburetor end of stem 94. The movement of valve 78 is limited by a screw 100 extending through the housing into chamber 86.

Fuel well 70 is connected to passage 42 in. shaft 34 by .a metering tube 110 secured, at its lower end in a block 112 and connected to passage 42 by

passages

114 and 116 and with thewell by a series of small ports 117 spaced longitudinally along the tube. Block 112 rotates in the counter-clockwise direction along with shaft 34 as the throttle valve is opened and carries tube 110 downwardly into the liquid fuel in the well, the tube being curved to conform to the direction of longitudinal movement as it is lowered and raised withthe rotation of block 112.

Fuel is also supplied through passage 118, port 120,

passages

116 and 42 to the discharge nozzle, this fuel being metered at port 120 which is varied in effective size by a metering valve 122 operated by a lever 124 in the direction to close the valve and by spring 126 to open the valve. Port 120 constitutes the source of fuel for idling and during idling the valve is held in its partially closed position by lever 124, and when the valve is in this position anair bleed port 127 is open to permit a controlled supply of air, to enter passage 116 and form a fuel-air mixture which is discharged through the main discharge nozzle 40.

The small chamber 128 around valve 122 is capable of holding ten to twenty drops of liquid fuel which under certain conditions, such as acceleration after prolonged deceleration, are readily available to provide a slightly rich mixture to. recoat the walls of the intake manifold with fuel which was removed therefrom during deceleration. In view of the small size of passage 118 and port '120, chamber 128 does not have suflicient time to fill with fuel if the duration of deceleration is short; however, under this condition fuel coating the manifold wall is not entirely'removed'and consequently the amount of fuel required to'recoat the walls is less and can be adequately supplied by the smaller quantity in chamber 128.

The location of the throttle in the venturi and the combination of the throttle and the discharge jet facilitate goodfuel atomization and distribution in the induction .passage immediatelydownstream from discharge tube 40. It is seen that the fuel on'leaving the discharge shaft construction, with the two shafts being interconnected for simultaneous movement, may, however, be used if desired in place of the single shaft construction shown in thedrawingsl I In the, operation of the vcarburetor thus far described,

, ventional automobile.

actuation of the throttle lever 36 rotates throttle 32 and simultaneously rotates block 112 downwardly into the fuel in metering well 70, carrying metering tube deeper into the fuel well and thus exposing an increasing number of holes 117 to the fuel. Also, movement of the block downwardly carries valve 122 away from lever 124, permitting the valve to open further and closingair bleed port 127. Venturi suction transmitted through nozzle 40,

passages

42, 116 and 114 controls the flow of fuel from metering tube 110 to the induction passage. Simultaneously, the fuel supplied from float chamber 50 to fuel well 70 is controlled by valve 78 in port 76 in response to manifold vacuum in chamber 86. As the manifold vacuum decreases with the opening of the throttle, the pressure in chamber 86 rises, causing diaphragm 90 to move to the left as seen in FIGURE 4, thus moving valve 7 it in the direction to increase the elfective size of port 76 and increase the flow of fuel into the fuel well. When the throttle is moved toward closed position, block 112 moves upwardly and the upper end of valve 122 engages lever 124 causingthe valve to move toward closed position to the required opening for proper idling.

The present carburetor is especially adapted for the prevention of air pollution by unburned vaporized fuel, both during the operation of the engine and after the engine has been shut off. Shaft 34 containing discharge passage 42, which functions as the fuel supply passage for both the main supply system and the idle system, is provided with an extension 132 projecting into the float chamber and having a passage 134 opening at the end. Passage 134 is aligned with but larger than passage 42, and a shoulder is formed therebetween. This shoulder serves as a seat 136 for a longitudinally movable valve element 138 disposed in passage 134. Valve element 138 is held open throughout most of the operation of the carburetor by a coil spring 140 reacting against the adjacent end of shaft 34 and a collar 142 on the valve element. A solenoid 144 of conventional construction is mounted on the float bowl and has a plunger 146 movable in alignment with element 138. The plunger extends through an opening 148 in the-end of the fuel bowl and abuts against,

a button 150 in the center of a diaphragm 152, the button in turn engaging the end of element 138. When the solenoid is energized, plunger 146 moves to the left, as

seen in FIGURE 4, and through button 150 moves valve element 138 against its seat 136, thereby completely interrupting and preventing the flow of fuel to the engine both through the idle and main systems. The solenoid is controlled by a manifold vacuum responsive switch (not shown) which energizes the solenoid whenthe manifold vacuum exceeds that existing for normal idling. A suitable vacuum switch mechanism is disclosed in my copending application Serial No. 570,187, filed March 7, 1956, now US. Patent No. 2,939,444.

In order to prevent the escape of fuel in the form of vapors after the engine has been shut off, air vent 64 is closed by the seating of valve 68 on the lower end of tube 63 and the main discharge and idle systems are closed by valve element 138. These two valves are operated by a lever mounted on a shaft 162 extending into the float chamber and carrying two

resilient levers

164 and 166, the former operating valve 68 to close the air vent and the latter engaging collar 142 to move valve element 138 to its seat. Lever 160 is operated through a linkage extending into the operators compartment and is actuated promptly after the engine is shut off so that any fumes forming from the heat of the engine will be entrapped in float chamber 50 and fuel well 70'.

In addition to the fuel vaporizing from the carburetor, a relatively large quantity of fuel normally evaporates from the fuel tank vented to the atmosphere in the con- To eliminate this source of air pollution, the present fuel system includes a vent tube 168 and passage 170 connected with the float chamber 50 above the fuel level. 1 It isthus seen that when the valve 68 is seated on the lower end of tube 63 and valve element 138 is seated on seat 136, the vehicle fuel system from the tank to the induction passage is completely sealed from the atmosphere, thus fully eliminating the escape of fumes from the fuel tank and carburetor while the engine is not operating.

In the present carburetor, the conventional choke valve in the air horn is eliminated and the enrichment of the fuel-air mixture for cold starting is obtained by a lever.

arrangement consisting of a lever 180 mounted on a shaft 182 extending into fuel well 70 and having a cam 184 mounted thereon for rotation therewith. When lever 180 is in position for normal warm engine operation, as shown in FIGURE 5, the cam engages lever 124 to position said lever and consequently valve 122 at the place for giving the correct idling mixture. When lever 180 and cam 184 are rotated counter-clockwise, as seen in FIGURE 5, the part 186 engages lever 188 and rotates said lever on shaft 190 causing arm 192 to engage a lug 194 on block 112 and rotate said block and tube 110 downwardly into the fuel in well 70 to increase thereby the fiowof fuel through the main discharge jet in response to air flow through the venturi. Lever 180 is held in position for normal idling by a spring 200 which urges the lever against an idle adjustment screw 202 threadedly received in a boss 204 on the side of the carburetor.

Although only one embodiment of the fuel system has been described in detail herein, various changes and modifications may be made without departing from the scope of the present invention.

I claim:

1. In a fuel system for an internal combustion engine: a fuel tank and a carburetor, said carburetor comprising walls forming an induction passage, a venturi in said passage, a throttle valve in said venturi, a housing positioned to one side of said induction passage and containing a chamber with a float therein and a fuel well separated by a wall from said chamber and interposed between said chamber and said induction passage, said wall having a port near the bottom thereof connecting said chamber and well, a valve means for varying the effective size of said port, a throttle shaft extending from said wellinto said venturi and having a longitudinal passage connecting said well with said venturi, a valve for closing said shaft passage, a lever for rotating said shaft to operate said throttle, a member in said well secured to said shaft for rotation therewith and having a passage extending outwardly from the passage in said shaft, an arcuate metering tubeextending upwardly from said member and having a plurality of holes, an idle fuel passage in said member connected with the passage in said shaft, a valve controlling said last mentioned passage, a means for opening said last mentioned valve for enriching the fuel-air mixture delivered to the engine, a vent means for said float chamber connected with said induction passage, a valve for closing said vent means, manifold vacuum responsive solenoid means for closing said shaft passage valve when the manifold vacuum reaches a predetermined degree, lever means for closing said vent valve and said shaft passage valve, and a conduit for connecting the float chamber above the fuel level with the tank above the fuel level therein.

2. In a fuel system for an internal combustion engine: a carburetor comprising walls forming an induction passage, -a venturi in said passage, a throttle valve in said passage, a housing positioned to one side of said induction passage and containing a chamber with a float therein and a fuel well separated by a wall from said chamber and interposed between said chamber and said induction passage,

said wall having a port near the bottom thereof connecting said chamber and well, a valve means for varying the effective size of said port, a means responsive to manifold vacuum for operating said valve, a horizontal rotatable shaft extending from said well into said venturi and having a longitudinal passage connecting said well with said member in said well secured to said shaft for rotation therewith and having a passage extending outwardly from the passage in said shaft, an arcuate metering tube extending upwardly from said member, an idle fuel passage in said member connected with the passage in said shaft, a valve controlling said last mentioned passage, a means for opening said last mentioned valve for enriching the fuel-air mixture delivered to the engine, a vent means for said float chamber connected with said induction passage, 21 valve for closing said vent means, a solenoid operated in response to manifold vacuum for closing said shaft passage valve when the manifold vacuum reaches a predetermined degree, and lever means for closing said ven-t valve and said shaft passage valve.

3. A carburetor, comprising walls forming an induction passage, a venturi in said passage, a throttle valve in said venturi, a housing positioned to one side of said induction passage and containing a chamber .with a float therein and a fuel well separated by a wall from said chamber and interposed between said chamber. and said induction passage, said wall having a port near the bottom thereof connecting said chamber and well, a valve means for varying the effective size of said port, a means responsive to manifold vacuum for operating said valve, a horizontal rotatable shaft extending from said well into said venturi and having a longitudinal passage connecting said well with said venturi, a valve for closing said shaft passage, a lever for rotating said shaft, 21 member in said well secured to said shaft for rotation therewith and having a passage extending outwardly from the passage in said shaft, an arcuate metering tube extending upwardly from said member and having a plurality of holes, an idle fuel passage in said member connected with the passage in said shaft, a vent means for said float chamber, a valve for closing said vent means, means for closing said shaft passage valve when the manifold vacuum reaches a predetermined degree', and lever means for'closing said vent valve and said shaf-t passage valve.

4. In a fuel system for an internal combustion engine; a fuel tank and a carburetor, said carburetor comprising walls forming an induction passage, a venturi in said passage, a throttle valve in said passage, a housing positioned to one side of said induction passage and containing a chamber with a float therein and a fuel well separated by a wall from said chamber and interposed between said chamber and said induction passage, said wall having a port near the bottom thereof connecting said chamber and well, a valve means for varying the effective size of said port, a means responsive to manifold vacuum for operating said valve, a rotatable shaft extending from said well into said venturi and having a longitudinal passage connecting said well with said venturi, a valve for closing said shaft passage, a lever for rotating said shaft when the throttle is operated, a metering tube having a plurality of holes connected to said shaft and-adapted to be raised and lowered in the fuel in said well, a vent means for said that chamber, a valve for closing said vent means, means for closing said shaft passage valve when the manifold vacuum reaches a predetermined degree, lever means for closing said vent valve and said shaft passage valve, and a conduit for connecting the float chamber above the fuel level with the tank above the fuel level therein.

5. A carburetor, comprising walls forming an induction passage, a venturi and throttle in said passage, a fuel well, a horizontal rotatable shaft extending from said well into said venturi and having a longitudinal passage connecting said well with said venturi, a valve forclosing said shaft passage, a lever for rotating said shaft when the throttle is operated, a member in said well secured to said shaft for rotation therewith and having a passage extending outwardly from the passage in said shaft, an arcuate metering tube extending upwardly from said member and having a plurality of holes, a vent means for said float chamber connected with said induction passage, a valve for closing said vent means, manifold vacuum controlled solenoid means for closing said shaft passage valve .when the manifold vacuum reaches a predetermined degree, and lever means for closing said vent valve and said shaft passage valve.

6. In a fuel system for an internal combustion engine: a fueltank and a carburetor, said carburetor comprising an induction passage, a housing having a chamber with a float therein, a main fuel discharge passage, a valve controlling said discharge passage, a vent means for said float chamber connected with said induction passage, a valve for closing said vent means, lever means for closing said vent valve and said passage valve, and a conduit for connecting the float chamber above the fuel level with the tank above the fuel level therein.

7. In a carburetor: an induction passage, a housing having a chamber, a main fuel discharge passage, a valve controlling said discharge passage, a vent means for said chamber, a valve for closing said vent means, means responsive to manifold vacuum for closing said passage valve, and lever means for closing said vent valve and said passage valve.

58. In a carburetor: a housing having a fuel chamber,

afuel discharge passage-connected to said chamber, a

chamber, a valve for closing said vent means, and manifold vacuum controlled solenoid means for closing said passage valve when the manifold vacuum reaches a predetermined degree.

9. A carburetor for an internal combustion engine, comprising Walls forming an induction passage, a venturi in said passage, a throttle valve in said venturi, a housing positioned to one side of said induction passage and con taining a chamber with a float therein and a fuel well separated by a wall from said chamber and interposed between said chamber and said induction passage, said wall having a port near the bottom thereof connecting a throttle therein: a fuel bowl, an idle system including a passage connecting said bowl below the normal fuel level with the induction passage adjacent the throttle, a restriction in said passage below said fuel level, a valve controlling said restriction, a passage connecting said fuel bowl above the normal fuel level with said first passage below said fuel level and posterior to said restriction, and a valve in said first passage posterior to the point at which said second passage connects with said first passage for closing said first passage.

11. In a carburetor having an induction passage: a fuel bowl, an idle system including a passage connecting said bowl below the normal fuel level with the induction passage, a restriction in said passage below said fuel level, apassage connecting a source of air with said first passage below said fuel level and posterior to said restriction, and a valve in said first passage posterior to the point at which said second passage connects with said first passage for closing said first passage.

References Cited in the file of this patent UNITED STATES PATENTS 1,220,965 Duvall Mar. 27, 1917 2,315,716 Leibing Apr. 6, 1943 2,617,638 Udale Nov. 11, 1952 2,776,821 Davis Jan. 8, 1957 2,894,734 Wentworth July 14, 1959 2,894,736 Wentworth July 14, 1959 2,905,455 Eberhardt Sept. 22, 1959