US3822058A

US3822058A - Carburetor

Info

Publication number: US3822058A
Application number: US00289158A
Authority: US
Inventors: E Carter
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-09-14
Filing date: 1972-09-14
Publication date: 1974-07-02
Anticipated expiration: 1991-07-02

Abstract

A fuel carbureting device having a housing with an air intake passage therethrough and an engine mounting fixture and utilizing a unique fuel-metering and throttle system including an elongated hollow fuel tube axially movable in the housing and coupled to a source of fuel at an outer end and having an open inner end into which an elongated flat-tapered fuel metering needle is disposed, the needle being essentially fixed in position except for slight axial movement by rotation of an external adjustment knob; the system also including a sliding throttle plate having a relatively large opening through its planar surface registrable with the air intake passage to a degree determined by the throttle linkage, opening of the carburetor''s throttle being accomplished through linkage which causes the plate to move so that more of the opening therein is exposed to the air intake passage, throttle plate movement also causing movement of the fuel tube in an axial direction toward the tip of the tapered needle to enlarge the fuel-metering orifice at the inner end of the fuel tube.

Description

United/States Patent 191 ,9 Carter 111 3,822,058 [451 July 2,1974

FOREIGN PATENTS OR APPLICATIONS 1,219,207 1/1971 1 Great Britain 261/44 R Primary Examiner-Tim R. Miles Attorney, Agent, or FirmSpensley, Horn &' Lubitz 57] ABSTRACT A fuel carbureting device having a housing with an air intake passage therethrough and an engine mounting fixture and utilizing a unique fuel-metering and throttle system including an elongated hollow fuel tube axially movable in the housing and coupled to a source of fuel at an outer end and having an open inner end into which an elongated flat-tapered fuel metering needle is disposed, the needle being essentially fixed in position except for slight axial movement by rotation of an external adjustment knob; the system also including a sliding throttle plate having a relatively large opening through its planar surface registrable with the air intake passage to a degree determined by the throttle linkage, opening of the carburetors throttle being accomplished through linkage which causes the plate to move so that more of the opening therein is exposed to the air intake passage, throttle plate movement also causing movement of the fuel tube in an axial direction toward the tip of the tapered needle to enlarge the fuel-metering orifice at the inner end of the fuel tube.

1 Claim, 10 Drawing Figures 1 l 1 I //////X 4/ ///I 73 V B 11- J 4| 39 27 31 2:5 i \1 43 4o 65 a 1 l T W A I A 11 f I n 62-.- ii 69 ///////l// 1 CARBURETOR BACKGROUND OF THE INVENTION Most conventional carbureting devices use a liquid fuelable reservoir in conjunction with throttle and fuelmetering arrangements. Although these devices are used extensively in the automobile industry, their efficiency is generally low and results in low fuel mileage, unclean exhaust emission and high frequency of costly tearing down and cleaning procedures. Recently, a carbureting device without a liquid fuelable reservoir has been developed, but its system for regulating the mixing of fuel and air is mechanically complicated and relatively expensive to manufacture. This type of carburetor has also experienced problems when used on a high compression engine where the suction force created within this type of engine tends to cause the carbure tors sliding throttle mechanism to jam.

SUMMARY OF THE INVENTION In view of the foregoing factors and conditions characteristic of the prior art, it is a primary object of the present invention to provide a new and improved carburetor for regulating the mixing of fuel and air.

Another object of the present invention is to provide a carburetor wherein the mixing of air and fuel can be easily regulated and adjusted.

Still another object of the present invention is to provide a carburetor for regulating the mixing of fuel and air which is comprised of a few simple parts and is easily assembled.

Yet another object of the present invention is to provide an inexpensively maintainable carburetor of the type having no internal fuel reservoir.

Still a further object of the present invention is to provide an improved carburetor for regulating and mixing of fuel and air to high compression engines.

According to an embodiment of the present invention, a carburetor is provided for adjustably controlling the amount of fuel and air introduced to an engine, the carburetor including a carburetor housing with an air intake passage and an axially aligned air-fuel exit passage and with an elongated hollow fuel delivery tube axially movably mounted in the housing, the tube including an external fuel input end and an internal fuel metering end. The carburetor also includes a throttle plate having parallel broad planar surfaces with a throttle opening therethrough, the plate being slidably disposed in the housing with the throttle opening registerable with the intake and exit passages to a desired changeable degree. The plate includes throttle means for moving the plate and the tube in a direction essentially parallel to the longitudinal axis of the tube. An elongated fuel-metering needle having an elongated flat tapered end portion extends into the internal fuelmetering end of the tube and defines at the internal end an approximate elliptical fuel-metering orifice which essentially linearly enlarges with movement of the plate and tube in a throttle-opening direction exposing more of the plates throttle-opening to the intake and exit passages. I

The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. The present invention, both as to its organization and manner of operation, together with further objects and advantages thereof, may best be understood by making reference to the following description taken in conjunction with the accompanying drawings in which like reference characters refer to like components in the several views.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic drawing of a basic carbureting device of the type not incorporating a liquid fuel reservoir;

FIG. 2 is a prospective view of a carbureting device constructed in accordance with the present invention;

. FIG. 3 is a sectional view of the carburetor shown in FIG. 2, taken along line 33;

FIG. 4 is a sectional view taken along line 44 of FIG. 2;

FIGS. 5a and FIG. 5b are enlarged cross-sectional illustrations of the fuel-metering needle and tube that define a changeable fuel-metering orifice therebetween;

FIG. 6 is a plan view of the throttle value plate member of the carburetor device shown in FIGS. 3 and 4;

FIGS. 7 and 8 are views showing the opposite ends of the throttle value plate of FIG. 6; and

FIG. 9 is a plan view illustrating the relationship between the fuel-metering orifice and the throttle value plate with respect to the carburetors throat when the mechanism is in a partial open throttle condition.

DESCRIPTION OF THE INVENTION Referring now to the drawing and more particularly to FIGS. 1 and 2, there is shown a carbureting device or carburetor 10 having an air intake 11, an air throttle mechanism 12, a fuel intake 13, a fuel-metering mechanism l4, and an engine mounting device or fixture 15. Referring now also to FIGS. 3 and 4, it can be seen that the air throttle mechanism 12 and the fuel-metering mechanism 14 are incorporated in the carburetors housing 16 which basically includes a central elongated rectangular plate 17 having a relatively large rectangular opening 18 appropriately cast or machined therein, the opening 18 being bounded by a first end wall 19, an opposite second end wall 20, and :side walls 21.

Mounted above and below the plate 17 by machine screws 22 or the like, in order to create a chamber 23 therebetween, are upper and

lower plates

25 and 26, respectively. A bore 27, along the longitudinal axis (not shown) of the carburetor 23, is provided in order to slideably accept a fuel delivery end 28 of a hollow cylindrical liquid fuel tube 31 therethrough. A conventional flexible fuel hose connector 32 is suitably mounted to the tubes end 28 to convey fuel to the interior of the tube 31. As can best be seen in FIGS. 3 and 4, a compressible helical coil spring 33 is mounted within the chamber 23 about the tube 31 and between the first end wall 19 and an annular anchor flange 34 which is fixedly attached near an end 35 of the tube 31.

The fuel-metering mechanism 14 includes, along with the liquid fuel tube 31, a fuel-metering needle 36 having a flat, gradually tapering end 37 and an opposite, threaded end 38. A fuel-metering adjustment knob 39 is mounted on the needles end 38 by a set screw 39a, as illustrated in FIG. 4.

An enlarged sleeve 40 is mounted in the cavity 23, extending through a bore 41 in the second end wall 20. The sleeves open end 42 lies adjacent the knob 39 and its other end 43 is crimped or otherwise provided with a decreased diameter opening through which the needle 36 extends. A defonnable plastic cylinder 44 is disposed within the sleeve 40, and a detent screw 45 is threadably housed in a threaded hole 46 in the housing and extends through an aperture 47 in the sleeve 40 to contact and deform inwardly the plastic cylinder 44. This effectively causes the inner wall of the cylinder 44 to enter the grooves of the needles threaded end 38 and act as a threaded nut so that rotation of the needle about its longitudinal axis will cause its axial movement. The sleeves crimped end 43 is sealed against fluid loss by a conventional resilient o-ring 48, usually rubber, disposed between the end 43 and the adjacent end of the plastic cylinder 44. In its extreme inward position as urged by spring 33, the tubes end 35 is pressed against the o-ring 48 to completely seal off fuel flow from the tube 31 (see FIGS. 3 and 4).

As will be described later, the fluid fuel tube 31 may be caused to move axially in the direction indicated by an arrow A. This action moves the end 35 of the fuel tube 31 relative to the fuel-metering needle 36 towards its diminishing thickness end 37. This relative movement effectively changes the size of an orifice 49 defined by a flat surface 50 of the flat tapered needle 36 and an inner wall 31a of the hollow fluid fuel tube 31. For example, FIGS. a and 5b illustrate the enlarging of the fuel-metering orifice 49 from a relatively small opening in FIG. 5a to a relatively larger opening in FIG. 5b, with relative movement of the fuel tube 31 in the direction indicated by arrow A. This relative movement can also be obtained, over a lesser range, by the aforementioned axial movement of the needle 36 through rotation of the adjustment knob 39.

With reference now to the air throttle device 12 of the presentcarburetor 10, it includes a sliding throttle valve plate 51 of any suitable material such as a phenolic or metal. The plate 51 is generally rectangular in shape having a length less than the length of the chamber 23 and a thickness and width dimension to slideably fit in the chamber 23, as shown in FIGS. 3 and 4. The plate 51 includes a throttle opening 52 through the plates broad surfaces, and an axial bore 53, as illustrated in more detail in FIGS. 6-8. The plate 51 is also provided with a pair of roller bearings 54 mounted on cantilevered pins 55 extended into appropriate notches 56 in the sides 57 of the plate 51. These bearings tend to decrease frictional forces between the broad surfaces of the sliding plate and the inner walls of the housings upper and

lower plates

25 and 26. This is especially advantageous when the carburetor is mounted on a relatively high compression engine which creates a high pressure differential between the throat 58 of the air intake 11 and the matching diameter throat 59 of the engine mounting fixture 15.

The plate further includes a transverse bore 60 to accommodate an anchor rod 62 terminating an accelerator cable 63, the cable extending through a slot 64 which lies midway between and parallel to the broad surfaces of the sliding plate 51 and extends between the axial bore 53 and transverse bore 60. A second axial bore 65 is disposed centrally in an end wall 66 of the plate 51 adjacent the chambers second end wall 20, and is dimensioned to slidably accept the hollow sleeve 40.

At the sliding plates opposite end 67, the axial bore 53 has a diameter to accept the tube 31, the helical coil spring 33, and the anchor flange 34. However, the bore 53 has a reduced diameter portion 68 allowing communication between the larger diameter portion of the bore 53 and the throttle opening 52 for only that portion of the tube 31 extending beyond the anchor flange 34.

In the position of the sliding throttle plate 51 shown in FIGS. 3 and 4, it can be seen that the plates broad surfaces are totally disposed between the throats of the air intake 11 and the mounting fixture 16 to effectively cut off the flow of air through the carburetor 10. As noted before, the spring 33 biases the fuel tube 31 in the direction (1B) opposite to that indicated by arrow A. The tubes anchor flange 34 thereby exerts pressure in this direction against the sliding throttle plate 51 at the reduced diameter portion 68 where the flange 34 abutts. Thus, the normal closed throttle condition will exist both for the air throttle and fuel-

metering mechanisms

12 and 14 until an external force is exerted on the plate 51 by the placing of a tension force on the throttle control cable 63 at a point beyond the housingmounted conventional adjustable Boden cable terminal fixture 69.

The pulling of the control cable 63 in the direction of the arrow A will cause the sliding plate 51 to push against the anchor flange 34 and thereby cause the movement of both the plate 51 and the fuel tube 31. This moves the throttle opening 52 into greater and greater communication with the throats of the air intake and mounting devices 11 and 15, while at the same time causing relative movement between the tubes end 35 and the flat tapered fuel-metering needle 36. Thus, air passage through the carburetor 10, as governed by the throttle mechanism 12, is simultaneously increased with a predetermined increase of fuel being metered by the carburetors mechanism 14, as clearly illustrated in FIG. 9. It will be noted from the last mentioned figure that the fuel exiting end 35 of the tube 31 is always positioned in the throttle opening 52 adjacent the air passage through the

throats

58 and 59 to affect the most efficient mixing of the air and fuel.

The carburetor is provided with a fine fuel-metering adjustment operable through the aforementioned knob 39 to increase or decrease the amount of fuel passing through the orifice 49. An engine idling adjustment is also provided by rotating an adjustment screw 70 (see FIG. 4). The screw 70 has a threaded shank portion 71 restrained by a spring 71a and threadably engaged in a threaded hole in the upper housing plate 25 adjacent the second end wall 20 of the plate 17. The shank portions end 72 is tapered to a point, the conical surface of which engages a beveled notch 73 in the upper planar surface of the sliding throttle plate 51, shown in FIG. 3. With right hand thread, clockwise rotation of the screw 70 moves the shank portion 71 inwardly and the screws end 72 pushes against the surface of the notch 73 to move the plate 51 away from the end wall 20. It can thus be seen that the throttle plates maximum excursion in the direction B is limited bythe adjustment screw 70 for a desired engine idling speed.

From the foregoing it should be evident that there has herein been described a relatively simple, compact, and a lightweight carburetor that is highly-efficient and economical to fabricate and maintain and which may be used on high compression engines.

The materials used in fabricating the invention are not critical and any material generally considered to be suitable for a particular component and function may be substituted for the material specifically identified herein. For example, the carburetors housing and fixtures mounted thereon may be molded or machined from a light-weight metal such as aluminum, for example, and ionized if desired.

It should be realized from the above description that the invention is susceptible to modifications and other embodiments. Furthermore, it should be noted that the various components shown in the figures are not drawn to scale. Accordingly, it is intended that the foregoing disclosure and showing in the drawings shall be considered only as illustrations of the principles of this invention.

What is claimed is:

1. A carburetor for adjustably controlling the amount of fuel and air introduced to an engine on which the carburetor is mounted comprising:

a. a carburetor housing with an air intake passage and an axially aligned air-fuel exit passage;

b. an elongated hollow fuel delivery tube axially movably mounted in said housing, said tube including an external fuel input end and an internal fuelmetering end;

c. a throttle plate having parallel'broad planar surfaces with a throttle opening therethrough, said plate being slidably disposed in said housing with said throttle opening registerable with said intake and exit passages to a desired changeable degree, said plate includingthrottle means for moving said plate and said tube in a direction essentially parallel to the longitudinal axis of said tube and having an elongated bore therethrough axially aligned with the longitudinal axis of said tube;

d. an elongated fuel-metering needle having an external end and an axially opposite elongated flattapered end portion, said needle passing through said bore and extending into said internal fuelmetering end of said tube and defining at said internal end a fuel-metering orifice which essentially linearly enlarges with movement of said plate and tube in a throttle-opening direction exposing more of said throttle opening to said intake and exit passages, said needle including a threaded portion adjacent said external end;

e. fuel adjustment means for axially moving said needle relative to said tube coupled to the external end of said elongated fuel-metering needle and including a hollow sleeve with a deformable hollow liner coaxially disposed in said sleeve, said sleeve slidably extending through said elongated bore in said plate and said needle extending through the bore in said hollow liner;

f. a rotatable adjustment knob fixedly attached to said external end of said needle, said needle including a threaded portion adjacent said external end; and

g. a detent screw mounted in said housing passing through an aperture in said sleeve and deforming inwardly a portion of said liner to contact said threaded portion of said needle whereby said needle is moved axially with the rotation of said adjustment knob.

Claims

1. A carburetor for adjustably controlling the amount of fuel and air introduced to an engine on which the carburetor is mounted comprising: a. a carburetor housing with an air intake passage and an axially aligned air-fuel exit passage; b. an elongated hollow fuel delivery tube axially movably mounted in said housing, said tube including an external fuel input end and an internal fuel-metering end; c. a throttle plate having parallel broad planar surfaces with a throttle opening therethrough, said plate being slidably disposed in said housing with said throttle opening registerable with said intake and exit passages to a desired changeable degree, said plate including throttle means for moving said plate and said tube in a direction essentially parallel to the longitudinal axis of said tube and having an elongated bore therethrough axially aligned with the longitudinal axis of said tube; d. an elongated fuel-metering needle having an external end and an axially opposite elongated flat-tapered end portion, said needle passing through said bore and extending into said internal fuel-metering end of said tube and defining at said internal end a fuel-metering orifice which essentially linearly enlarges with movement of said plate and tube in a throttleopening direction exposing more of said throttle opening to said intake and exit passages, said needle including a threaded portion adjacent said external end; e. fuel adjustment means for axially moving said needle relative to said tube coupled to the external end of said elongated fuel-metering needle and including a hollow sleeve with a deformable hollow liner coaxially disposed in said sleeve, said sleeve slidably extending through said elongated bore in said plate and said needle extending through the bore in said hollow liner; f. a rotatable adjustment knob fixedly attached to said external end of said needle, said needle including a threaded portion adjacent said external end; and g. a detent screw mounted in said housing passing through an aperture in said sleeve and deforming inwardly a portion of said liner to contact said threaded portion of said needle whereby said needle is moved axially with the rotation of said adjustment knob.