US3350073A

US3350073A - Carburetor

Info

Publication number: US3350073A
Application number: US507752A
Authority: US
Inventors: Raymond R Hill
Original assignee: Individual
Current assignee: Individual
Priority date: 1965-11-15
Filing date: 1965-11-15
Publication date: 1967-10-31
Anticipated expiration: 1984-10-31
Also published as: FR1503020A

Description

Oct. 31, 1967 R. R. HILL 3,350,073

' CARBURETOR Filed Nov. 1.5, 1965 2 Sheets-Sheet l I INVENTOR. Ammo/v0 P0615? H/LL BY F I 5-- 2 @M/ FM ATTOENEVS R. R. H l L L CARBURETOR Oct. 31, 1967 2 Sheets-Sheet 2 Filed Nov. 15, 1965 FIE- FIE--4;

INVENTOR. RA VMOA/D 065.? HILL ATTORNEYS 3,350,073 CARBURETOR Raymond R. Hill, 11 White Cottage Road,

- Angwin, Calif. 94508 Filed Nov. 15, 1965, Ser. No. 507,752 3 Claims. (Cl. 261-44) ABSTRACT OF THE DISCLOSURE A fuel injection carburetor having a variable venturi defined by a sliding valve door and having a vacuum operated fuel valve for automatically closing off the fuel supply when the engine is turned off.

Summary of invention This invention relates to carburetors for internal combustion engines and more particularly to improvements in fuel injection carburetors of the type shown in my US. Patent No. 3,182,974 which was issued on May 11, 1965.

My above mentioned patent shows fuel injection carburetors in which a valve door moves responsive to increasing demand for fuel-air mixture to provide a variable venturi, and fuel is discharged into the variable venturi by a fuel discharge mechanism which distributes the fuel uniformly over the area of the venturi. Additionally, the carburetors shown in my above mentioned patent provide a vacuum biasing means which automatically adjusts the richness of the fuel-air mixture so that the mixture is more lean under cruising conditions than it is under acceleration conditions.

In accordance with this invention, I have provided an improved carburetor of the same general type as that shown in my patent, but the improved carburetor employs a sliding door for the mixing chamber with the door opening in response to the requirements of the carburetor for increased fuel-air mixture, and I have provided an automatic vacuum shut-off valve which closes off the fuel supply for the carburetor immediately when the engine is turned off and prevents flooding of the carburetor by fuel leakage after the engine has been turned oif.

Other objects and advantages of the invention will become apparent from the following description read in conjunction with the attached drawings in which:

FIG. 1 is an elevation view of a carburetor constructed in accordance with the principles of this invention;

FIG. 2 is a vertical section view of the carburetor of FIG. 1;

FIG. 3 is a top plan view of the carburetor of FIG. 1;

FIG. 4 is a cross-sectional view of FIG. 2 taken along plane 4 4.

Referring now in detail to the drawings and particularly .to FIG. 1, the carburetor in general is indicated by the numeral 10. The carburetor 10 is shown in FIG. 1 as mounted on an intake manifold 12 secured thereto by bolts 13.

Referring now to FIG. 2, a vacuum chamber 14 is separated from a mixing chamber 16 by a butterfly valve 18. The buterfly valve 18 is mounted on axle 20 which is rotatable within axle bearings 22.

The top wall of the mixing chamber 16 is formed by a valve door 24 which is slidable along the upper portion of the mixing chamber 26. The valve door 24 has a slanted portion 25 and a flat portion 27. The valve door 24 forms an opening 23 with a front wall 29 of the mixing chamber 16 through which air passes as the door moves to its open position. As indicated in the drawings, the slanted portion 25 and the surrounding portions of the body are rectangular, but they may take other shapes.

. United States Patent Mounted on the valve door 24 are valve door bearing

blocks

28 and 30 supporting a Teflon sleeve bearing 31 slidable on a rod 32. Rod 32 is secured on the carburetor body by means of snap rings 34. A Teflon ring 36 and a cylindrical sleeve 38 act as a stop against bearing block 30 when the valve door 24 is in its closed position as indicated in phantom. A finger 40 is mounted on a pivot shaft 42 and extends through the plug 43 pivotally mounted in bearing block 30. The finger 40 biases the valve door 24 towards the closed position as explained later.

Sleeve 44 is connected to the valve door 24 at point 46. The sleeve receives a metering rod 48 from one end and has a piston 50 mounted on its opposite end by snap rings 51. The piston 50 is mounted inside of a cylinder 52 which is in turn mounted in the carburetor body. A seal 54 closes off the cylinder 52 from the mixing chamber 16. A vacuum intake passageway 5 6 communicates with the Vacuum chamber 14 and opens into the cylinder 52. The cylinder 52 is opened to the air at the opposite end from seal 54. Thus, piston 50 is subjected to the differences in pressure between the outside air pressure and the pressure in the vacuum chamber 14. Where desirable, the other end of the cylinder may be connected to the mixing chamber to subject the piston to the pressure differential across the butterfly valve 18, but more pronounced response of the piston to the vacuum in the vacuum chamber is obtained with the arrangement illustrated.

The metering tube 48 has a bore 58 which is opened to the mixing chamber 16 through a series of fuel supply ports 60. Set screw 62 has a conical head such that the set screw 62 may be adjusted to force the metering tube into the mixing chamber 16. The spring 64 biases the metering tube 48 away from the mixing chamber 16 and against the set screw 62.

A fuel shut off valve is indicated generally as 66 and has a housing with an upper portion 68 and a lower portion 69 fastened together by bolts 71 (see FIG. 1). The upper portion of the housing 68 has an opening at 70 adapted to be connected to a fuel pump for supplying fuel to the housing 68 from the tube 72, and an opening at 74 for discharging fuel to the metering tube 48. A plunger 78 having a rubber gasket 82 is biased by the spring 7 6 down against the inner sleeve 80 with the plunger 7'8 and sleeve 80 having valve seats 79 and 81 respectively. A piston 84 having a flange 85 fits within a retaining plug 86 and rests upon a diaphragm 88. A vacuum intake port 90 communicates with the vacuum chamber 14 and opens into a chamber 91 of the housing 68 through an aperture 92.

In the lower portion of the housing 69 (FIG. 2) the axle 22 of the butterfly valve has a flat portion 94 which contacts a lower piston 96. An air port 98 communicating with the outside empties into a ring 100 below the diaphragm 88.

Referring now to FIGS. 3 and 4, back-fire ports 102 are shown covered by plate 104 which is fastened to the valve door 24 by bolts 106. Clip 108 restricts the plate 104 in case of back fire. The biasing finger 40 is mounted on the shaft 42 such that when the valve door 24 moves to an open position the shaft 42 .will rotate in a counterclockwise direction as viewed in FIG. 1. Opposing this counterclockwise rotation is a spring 110* which is secured at one end to arm 1-12 and at the other end to arm .114 mounted on the shaft 42. The arm 112 fits Within a hole 116 in the mounting 118. Set screw 120 may be loosened to allow the arm 112 to be set in any given position within the mounting 118. Arm 114 fi'ts within a hole 122 in the shaft 42. Set screw 124 may be loosened to allow the arm 114 to be set in any given position within the shaft 42. A weight 12.6 is mounted on the arm 128 and may be positioned any place along the arm 128 by loosening the set screw 130. The weight 126 and the arm 128 combine to bias the shaft against clockwise rotation. Thus, adjustment of

arms

112 and 114 and positioning of weight 126 combine to influence the biasing effect on the shaft 42 which in turn effects the biasing force of the finger 40 upon the valve door 24.

The operation of the carburetor will now be explained. When the engine is started, the axle 20 is turned thus moving the butterfly valve 18 to an open position. The flat portion of the axle 94 pushes the lower piston 96 up against the diaphram 88, piston 84, and plunger 78 to permit the fuel to flow from the tube 72 through the inner sleeve 80 and out through the opening 74 to the metering tube 48. After the engine has begun to operate a vacuum is created in the vacuum chamber 14 which is communicated by the vacuum intake port 90 to the chamber 91. Since the ring 100 is at atmospheric pressure, due to air port 98, the diaphram is urged up against piston 84 and plunger 78. Thus, the difference in atmospheric pressure and the pressure in the vacuum chamber 14 holds the plunger 78 open to allow fuel to travel to the metering tube 48.

When the engine associated with the carburetor is in its idling condition a relatively strong vacuum is created in chamber 14 by the fluid demands of the engine. A very small minimum clearance adjustable for adjusting idling speed is provided between the periphery of the butterfly valve 18 and the adjacent Walls of the carburetor 10 to permit just sufficient fuel air mixture to pass therethrough to supply the idling requirements of the engine.

Under this idling condition, air enters the carburetor through the opening 23 and a small amount of fuel enters chamber 16 through the fuel supply ports 60 and the metering tube 48. The quantity of fuel supplied under idling conditions can be changed by adjusting screw 62 which will move the metering tube 48, thereby adjusting the number of fuel supply .ports 60 which are not covered by the sleeve 44. The interior of the sleeve at the right hand end shown in FIG. 2 is tapered over an area spanning several of the ports 60 so that movement of the sleeve on the metering tube causes a uniform change in fuel supply instead of an abrupt change.

When it is desirable to accelerate the engine on which the carburetor is employed butterfly valve 18 is opened by turning axle 20, thereby drawing fluid from the chamber 16 into ohamber 14 responsive to the pressure gradient across butterfly valve 18. When this flow of fluid out of chamber 16 causes a reduction in pressure in chamber 16 relative to atmospheric pressure which is applied to the upper side of the slanted portion of the door 25, the door 24 is accordingly pushed by component force to an open position in opposition to biasing spring 110. As door 25 moves to an open position it provides a generally rectangular opening 23 between the edge of the door and the front wall 29. The air requirements of the engine are drawn into chamber 16 through this opening. As door 24 moves to the open position, it also moves sleeve 44 thereby exposing additional fuel supply ports 60 in the metering tube 48. The additional fuel requirements of the engine are supplied through these additional exposed fuel supply ports 60.

It will be noted that the exposed fuel supply ports 60 are provided on a line which extends generally centrally through the opening between the free edge of the door 24 and the front wall 29 of the chamber 16. This position of fuel supply ports 60 at the vortex of the airstream entering the carburetor 10, coupled with the fact that the fuel supply ports 60 are directed laterally towards the ends of the opening 25 produces the maximum evaporation of fuel supplied from the fuel supply ports and the maximum uniformity of fuel air mixture produced by such evaporation. Further, the fact that additional fuel supply ports are exposed for each incremental increase in the size of the opening between valve door 24 and the front wall 29 insures that this uniformity of fuel air mixture is maintained regardless of the position of the valve door 24 and the quantity of air passing through the opening between valve door 24 and front Wall 29.

It should be noted that the line of action of tension spring with respect to the axis of arm 114 forms an acute angle which decreases towards zero degrees as door 24 opens, thus providing a reduction in the working arm of spring 110 as the door 24 is opened and the spring 110 is stretched.

When it is desirable to stop the engine on which the carburetor is employed, butterfly valve 18 is closed by manipulating the axle 20 to the idling position of the butterfly valve, thereby permitting the shut off 66 valve of the carburetor to close. The rotation of the axle 20 permits the lower piston 96 to drop back in its lower position. When the ignition is turned off to stop the engines demand for fuel from the chamber 14, the pressure in chamber 14 rises to atmospheric pressure and the pressure in chamber 91 also assumes atmospheric pressure. This results in the diaphragm 88 returning to its down position, and the piston 84 no longer being forced up against the plunger 78. Consequently, 78 is biased downwardly by the resilient spring 76 thereby closing off the flow of fuel through the inner sleeve 80. The foregoing reaction of the various components occurs instantaneously when the butterfly valve 18 is closed and the ignition turned off thereby preventing the flow of fuel into chamber 16 and a consequential flooding of the engine.

The effect of the operation of the piston cylinder combination, 50 and 52, is to provide more adequate control of the opening and closing of the valve door 25 as it is opened to a greater extent and to provide more immediate response of the valve door 24 to the closing of butterfly valve 18. Thus, atmospheric pressure applied to the outer side of piston 50 cooperates with low pressure in the vacuum chamber 14 to apply an additional biasing force to sleeve 44 tending to close the valve door 24 responsive to increase in the vacuum in chamber 14.

The piston cylinder combination, 50 and 52, automatically adjust the carburetor to provide different richness of fuel air mixture at different operating conditions of the engine. Thus, under cruising conditions, when the engine is running rapidly and the butterfly valve 18 is positioned in an intermediate, partially closed, position, a relatively high vacuum exists in the vacuum chamber 14. This high vacuum applied to the piston cylinder combination, 50 and 52, biases the valve door 24 towards more closed position than it would occupy if the piston cylinder combination, 50 and 52, were not present; this partial closing of the valve door 24 reduces the fuel supply ports 60 by closing off some ports without causing a corresponding reduction in the volume of air flowing past the valve door. In this Way, the piston cylinder combination causes a leaning of the fuel air mixture during cruising conditions; however, when the butterfly valve 18 is opened Wide for acceleration conditions of the engine, the vacuum chamber 14 is placed in more direct communication with the atmosphere; the degree of vacuum in the vacuum chamber is reduced, and the fuel air mixture becomes richer because the biasing effect of the piston cylinder combination is reduced.

As indicated above, the provision of many adjusting screws permits maximum adjustment of the carburetor to suit various environments.

The mixing chamber 16 while shown to be rectangular in shape can be made to any desired configuration. Thus, if it is desired the mixing chamber 16 can be formed in the shape of a trapezoid which would require, of course, that the valve door 24 be shaped similarly.

While the above description on the attached drawings describes one specific embodiment of the invention, it is apparent that the carburetor of the invention may be constructed with many modifications and dimensions, ar-

rangements of parts, and omission and addition of parts Without departing from the spirit and scope of the invention.

I claim:

1. In a carburetor comprising a carburetor body defining at least in part a vacuum chamber adapted to communicate with the intake manifold of an internal combustion engine and a fuel mixing chamber, and adjustable valve means for providing variable communication between the vacuum chamber and the mixing chamber, improved means for introducing fuel and air into the mixing chamber comprising:

(A) a valve door having a flat top portion and an inclined side portion, said door having an edge on said inclined portion adjacent to said body defining with said body an opening into said mixing chamber, means including bearings mounting said door for sliding movement on said body along flat portion responsive to air pressure on said inclined portion whereby said opening increases responsive to increasing vacuum in said mixing chamber,

(B) a metering tube located within the mixing chamber having,

(1) an axial bore adapted to be connected to a source of fuel, and

(2) discharge means communicating with the bore and having a fluid discharge area distributed along the length of the tube for introducing fuel into the mixing chamber,

(C) sleeve means slidable receiving the metering tube, with the sleeeve mounted on said valve door for movement with the valve door to an open position responsive to increasing vacuum in the mixing chamber thereby exposing an increasing amount of the fuel discharge area of the metering tube as the door opens, and

(D) resilient means biasing the door to a closed position.

2. The apparatus of claim 1 characterized further by the inclusion of (A) a fuel shut off valve comprising (1) a housing,

(2) means for supplying fuel to the housing,

(3) means for discharging fuel from the housing into the mixing chamber,

(4) plunger means located within the housing having a closed position preventing the flow of fuel through the housing and an open position permitting the flow of fuel through the hous- (5) resilient means biasing the plunger toward the closed position, and

(6) vacuum biasing means communicating with the vacuum chamber and biasing the plunger to an open position, and

(B) mechanical means interconnecting the adjustable valve means and the shut off valve for permitting the plunger to move to its closed position only when the adjustable valve means is closed.

3. In a fuel injection carburetor comprising a carburetor body defining at least in part a vacuum chamber adapted to communicate with the intake manifold of an internal combustion engine and a fuel mixing chamber and adjustable valve means having a closed position and defining at least in part one air passageway to the vacuum chamber for admitting air to the intake manifold, improved means for introducing fuel and air into the mixing chamber comprising: a valve door forming a wall of the mixing chamber and means mounting said valve door for movement responsive to increasing vacuum in the mixing chamber to provide an opening of increasing size in the Wall of the mixing chamber, a metering tube located within the mixing chamber having, an axial bore and discharge means communicating with the bore and having a fluid discharge area distributed along the length of the tube for introducing fuel into the mixing chamber,

(A) a housing,

(B) means for supplying fuel to the housing,

(C) means for discharging the fuel from the housing into the metering tube,

(D) plunger means located Within the housing having a closed position preventing the flow of fuel through the housing and an open position permitting the flow of fuel through the housing,

(E) resilient means biasing the plunger towards the closed position,

(F) vacuum biasing means communicating with the vacuum chamber and biasing the plunger to an open position, and

(G) mechanical means interconnecting the plunger and the adjustable valve means for permitting the plunger to move to its closed position only when the adjustable valve means is in closed position.

References Cited UNITED STATES PATENTS 10/ 1921 Henderson 261-49 X 6/1924 Hansen-Ellehammer.

12/ 1930 Atkins.

5/ 1965 Hill.

50 HARRY B. THORNTON, Primary Examiner.

RONALD R. WEAVER, Examiner.

Claims

1. IN A CARBURETOR COMPRISING A CARBURETOR BODY DEFINING AT LEAST IN PART A VACUUM CHAMBER ADAPTED TO COMMUNICATE WITH THE INTAKE MANIFOLD OF AN INTERNAL COMBUSTION ENGINE AND A FUEL MIXING CHAMBER, AND ADJUSTABLE VALVE MEANS FOR PROVIDING VARIABLE COMMUNICATION BETWEEN THE VACUUM CHAMBER AND THE MIXING CHAMBER, IMPROVED MEANS FOR INTRODUCING FUEL AND AIR INTO THE MIXING CHAMBER COMPRISING: (A) A VALVE DOOR HAVING A FLAT TOP PORTION AND AN INCLINED SIDE PORTION, SAID DOOR HAVING AN EDGE ON SAID INCLINED PORTION ADJACENT TO SAID BODY DEFINING WITH SAID BODY AN OPENING INTO SAID MIXING CHAMBER, MEANS INCLUDING BEARINGS MOUNTING SAID DOOR FOR SLIDING MOVEMENT ON SAID BODY ALONG FLAT PORTION RESPONSIVE TO AIR PRESSURE ON SAID INCLINED PORTION WHEREBY SAID OPENING INCREASES RESPONSIVE TO INCREASING VACUUM IN SAID MIXING CHAMBER, (B) A METERING TUBE LOCATED WITHIN THE MIXING CHAMBER HAVING, (1) AN AXIAL BORE ADAPTED TO BE CONNECTED TO A SOURCE OF FUEL, AND (2) DISCHARGE MEANS COMMUNICATING WITH THE BORE AND HAVING A FLUID DISCHARGE AREA DISTRIBUTED ALONG THE LENGTH OF THE TUBE FOR INTRODUCING FUEL INTO THE MIXING CHAMBER, (C) A SLEEVE MEANS SLIDABLE RECEIVING THE METERING TUBE, WITH THE SLEEVE MOUNTED ON SAID VALVE DOOR FOR MOVEMENT WITH THE VALVE DOOR TO AN OPEN POSITION RESPONSIVE TO INCREASING VACUUM IN THE MIXING CHAMBER THEREBY EXPOSING AN INCREASING AMOUNT OF THE FUEL DISCHARGE AREA OF THE METERING TUBE AS THE DOOR OPENS, AND (D) RESILIENT MEANS BIASING THE DOOR TO A CLOSED POSITION.