US2770254A - Carburetor metering valve - Google Patents

Description

NW; 13, 1956 H. G. BOLTON 9 3 CARBURETOR METERING VALVE Filed July 10, 1951 2 Sheets-Sheet l if x 17 13% 7 f 6 Z fnvenfr Harry 6 304% H. G. BOLTON CARBURETOR METERING VALVE 2 Sheets-Sheet 2 Filed July 10, 1951 jazz/6721 57 flak-71y Gfialfan aw I3. 5 2x 2? United States Patent CARBURETOR METERING VALVE Harry G. Bolton, Decatur, Ill., assignor to Borg-Warner Corporation, Chicago, Ill., a corporation of Illinois Application July 10, 1951, Serial No. 235,951

2 Claims. (Cl. 137625.48)

This invention relates to carburetors, and more particularly to a metering valve arrangement for a twin or double barrel type carburetor.

Twin or double barrel carburetors are well known, the usual arrangement thereof being to supply the fuel needs of one half of the cylinders of an engine through one intake manifold connected to one barrel and of the other half of the cylinders through a separate intake manifold connected to the other barrel of the carburetor. A primary difficulty, however, in this type of arrangement is that of supplying equal amounts of fuel simultaneously to the two intake manifolds so that uniform engine performance is obtained from all cylinders. Also, pulsations occurring in one intake manifold may affect adversely the fuel supply to the other intake manifold, since these pulsations may be communicated through the coin mon float valve chamber.

Objects of the present invention are to provide a new and improved double barrel type carburetor and more particularly an improved metering valve arrangement whereby uniformity of fuel supply to each barrel is maintained throughout the full range of adjustment of a single metering valveand whereby cross effects due to pulsations occurring in one barrel or intake manifold which may be communicated to the other barrel or intake manifold are substantially eliminated.

In accordance with one embodiment of this invention as applied to a generally conventional, double barrel type carburetor, a single metering valve is employed which is located in the float valve chamber and is in communication therewith at one end. As the valve is moved toward open position an annular passage is gradually eX- posed, to opposite sides of which passage are connected ports leading to the respective nozzles associated with each of the carburetor barrels. The valve is arranged so that communication between the two ports is obstructed by the valve body although communication between a port and the float chamber is relatively unimpeded except for the normal metering action of the valve. The valve is also so arranged that pulsations present in one carburetor barrel or port are dissipated before reaching the other port or barrel since such pulsations pass through the float valve chamber and the fuel contained therein and are substantially absorbed thereby.

Othe objects and advantages of the present invention will be apparent from the following detailed description thereof taken in conjunction with the drawings wherein:

Fig. l is a sectional view, taken substantially along the line 1-1 of Fig. 3, of a double barrel type carburetor constructed in accordance with one embodiment of this invention;

Fig. 2 is a horizontal, cross sectional view, taken substantially along the line 22 of Fig. l, and showing to advantage the double barrel arrangement;

Fig. 3 is an end view with the float valve chamber broken away to show the metering valve arrangement of this invention, the view being taken from the air intake end of the carburetor;

Fig. 4 is a vertical sectional view taken along line 4 4 of Fig. 3; and

Fig. 5 is an enlarged, detailed sectional view of the metering valve shown in Figs. 3 and 4.

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Referring now to the drawings, it will be seen that the twin carburetor of this invention comprises a double barrel housing 10 and a float chamber 11 mounted on the underside of the barrel housing 10. Two parallel extending barrels 12 and 13 are formed in the barrel housing 10 and are arranged to be located in horizontal relation to the entire engine (not shown) with which the carburetor is to be associated, the carburetor being of the side delivery type. Air intake ports are formed at the left ends of the two barrels, as viewed in Figs. 1 and 2, while discharge ports, adapted to be connected to the intake manifolds associated with the engine, are located at the right ends of the two barrels. Conventional choke valves 14 and 15 are disposed within the left end portions of the barrels 12 and 13, respectively, while throttle valves 16 and 17, respectively, are disposed in the right end portions of these two barrels, as shown in Fig. 2.

Liquid fuel is supplied to the float chamber 11 through a port 20 which communicates with the chamber through a passage 21 formed in the carburetor housing. The quantity of fuel in chamber 11 is regulated by float valve assembly 22, the opening of which valve is controlled by a float 23, located within chamber 11 and floating on the surface of the fuel therein. When the level of the .fuel drops below a predetermined value, the weighted valve member 22a is permitted to drop downwardly a short distance and thereby to open the lower end of the passage 21 into the chamber 11 to maintain the fuel supply therein.

A pair of idling valves 24 and 25 are associated, respectively, with the barrels 12 and 13 and control the admission into the throttle chamber portions thereof of fuel during the idling operation of the engine with which this carburetor is intended to be associated. A pair of main discharge nozzles 26 and 27 have their discharge ends located respectively in the venturi portions of the barrels 12 and 13 and are supplied with fuel from the chamber 11 in a manner to be described hereinafter. The carburetor so far described is conventional and, accordingly, it is believed, that no more detailed description thereof is necessary.

In accordance with the present invention, the fuel supplied to the nozzles 26 and 27 is closely and uniformly controlled through a novel metering valve arrangement 30 whereby not only is the amount of fuel supplied to both nozzles made equal, but also pulsations which may occur in one side of the carburetor system are substantially prevented from being communicated to the other side thereof. Referring particularly to Figs. 3, 4 and 5 it will be seen that the novel metering valve arrangement 30 of this invention is located in the lower mid portion of a block portion 31 of the carburetor, the portion 31 being disposed within the float valve chamber 11 and integrally formed with the underside of housing 10. For tion 31 has a vertically disposed passage or valve chamber 32 formed therethrough, the lower portion 32a of which is enlarged somewhat and threaded to receive the threaded outer periphery of the lower end of a valve holder 33. Valve holder 33 is of generally cylindrical configuration and the upper portion or stem 33b is substantially reduced in diameter as compared with the lower terminal portion. The lower end 33a extends beyond the bottom wall of float chamber 11, which is suitably apertured, and is provided with a transverse slot 330 at its lower extremity to receive a screwdriver tip, for example, whereby the position of the valve stem 33b in the chamber 32 may be adjusted.

A sleeve valve 34 is carried by the stem 33b, the lower end of the sleeve valve 34 resting on a shoulder 33d formed at the point of reduction in diameter of the valve holder. It will be noted that the outer diameter of the major portion of the sleeve valve 34 is made sufiiciently great so that a close fit is had between the outer portion thereof and the inner wall of the chamber 32, while the inner diameter of the sleeve 34 is made substantially greater than the outer periphery of the reduced stem portion 33b. In this manner angular misalignment of the valve stem without consequent binding of the valve sleeve in the passage 32 is permitted. There can also be lateral misalignment between the sleeve and the valve stem 33b because of this clearance. In one type of carburetor constructed in accordance with this invention this clearance was made to be of the order of .015 inch.

Sleeve valve 34 is retained in position against the shoulder 33d by an annular, dished-type spring washer 35, the underside of which washer bears against the upper end of the sleeve valve, the spring washer 35 being in turn retained by a ring 36 bearing against the upper side thereof and held in place by a rivet 37 or other suitable means carried by the upper end of the valve stem portion 33!).

Referring now particularly to Fig. 3, it will be noted that from diametrically opposite sides of the upper portion of valve chamber 32 there extend two passages 40 and 41, these passages communicating at their ends remote from the chamber 32 with the nozzle chambers 42 and 43 of the nozzles 26 and 27, respectively. The inner ends of these passages 40 and 41 are sharply reduced to provide restricted orifices 40a and 41a, respectively, at the points of communication with the chamber 32. By selecting the degree of restriction of orifices 40a and 41a, the maximum port opening may be predetermined irrespective of the maximum opening of the metering valve 30.

When the valve holder 33 is in its uppermost position, as viewed in Fig. 3, that is, is screwed fully into the housing block 31, the sleeve valve 34 completely obstructs the restricted inner ends of the passages 40 and 41. However, the upper end of the sleeve valve 34 is tapered, as indicated at 34a, to provide a valving surface so that by withdrawing the valve holder slightly, the tapered or valving surface 34a may be placed in communication with the ports 40a and 41a, the degree of valve opening being obviously determined by the extent to which the valve 34 is moved downwardly, as viewed in Figs. 3 and 4.

From the foregoing it will be evident that fuel in the float valve chamber 11 is, when metering valve 30 is opening, communicated to the main nozzles 26 and 27 through an annular passage 34!; having a right triangular cross-section. It will be evident, further that the passage 34b from port 40a to port 41a is circuitous and that the line of least resistance is normally from one port through the triangular cross-section passage 34b into the chamber 11 and from thence downward and into the other port. Accordingly, pulsations occurring in one nozzle supply line will be both obstructed by the valve 34 and also dissipated in passing through the float valve chamber 11. In practice it has been found that this arrangement substantially eliminates pulsations from one barrel of the carburetor affecting the other barrel of the carburetor, while ensuring uniform delivery of fuel to both barrels.

While this invention has been described particularly in connection with a double barrel type carburetor, because this is the most common application of this invention, my tests have indicated that it is equally suitable for carburetors having more than two barrels, it being requircd only that an additional port be provided in the side of the valve chamber for each additional barrel. Preferably, regardless of the number of ports, the ports should be equally spaced from each other. Also, while this invention has been described in connection with an arrangement where the metering valve supplied the total fuel requirements of the carburetor, the metering valve arrangement may also be used only as a supplementary supply, as for example, where fixed jets are fed directly from the bowl of the carburetor and supply the major portion of the total fuel flow. These variations and other Y 4 combinations will be readily apparent to those skilled in the art.

Where herein the various elements of the carburetor of this invention have been referred to as being located in a right or a left position, or in an upper or a lower position, it will be understood that this has been solely for the purpose of facilitating description and that such references relate only to the relative positions of the parts as shown in the accompanying drawings.

While but one embodiment of this invention has been shown and described, it will be understood that many changes and modifications in addition to those referred to herein may be made without departing from the spirit or scope of the present invention.

What is claimed is:

1. A metering valve assembly for a carburetor having a fuel feeding nozzle associated therewith and a reservoir for fuel, said metering valve assembly including means defining a valve chamber having one end thereof adapted for communication with said reservoir and circumferentially spaced ports formed in said chamber and spaced from said one end, a sleeve valve journalled in said chamber and having a conically tapered metering surface formed thereon adjacent to said one end for controlling the flow of fuel through said chamber to said ports, said tapered metering surface and said adjacent end wall of said chamber defining an annular passage of generally triangular cross-section, the wider end of which passage adapted for communication with said reservoir and the narrower end whereof may be placed in communication simultaneously and equally with each of said ports, and means for adjusting the position of said valving surface with respect to said ports including a valve stem surrounded by said sleeve and spaced therefrom, said stem having an enlarged portion provided with screw threads and resilient means for holding said sleeve valve on said valve stem by pressure on the ends of said sleeve valve, whereby said sleeve valve may be moved axially by rotation of said screw threaded portion and said sleeve valve is laterally movable relative to said stem.

2. A metering valve assembly for a carburetor having a fuel feeding nozzle associated therewith and a reservoir for fuel, said metering valve assembly including means defining a valve chamber having one end thereof adapted for communication with said reservoir and circumferentially spaced ports formed in said chamber and spaced from said one end, a sleeve valve journalled in said chamber and having a conically tapered metering surface formed thereon adjacent to said one end for controlling the flow of fuel through said chamber to said ports, said tapered metering surface and said adjacent end wall of said chamber defining an annular passage of generally triangular cross-section, the wider end of which passage is adapted for communication with said reservoir and the narrow end whereof may be placed in communication simultaneously and equally with each of said ports, and means for adjusting the position of said valving surface with respect to said ports including a valve stem surrounded by said sleeve valve and spaced therefrom, and resilient means for holding said sleeve valve on said valve stem by pressure on the ends of said sleeve valve, whereby said sleeve valve is laterally movable relative to said stem.

References Cited in the file of this patent UNITED STATES PATENTS 112,216 Broadbent et al Feb. 20, 1871 817,153 Barr Apr. 10, 1906 1,186,797 Kingston June 13, 1916 1,536,415 Beck et al. May 5, 1925 2,016,878 Vickers Oct. 8, 1935 2,209,442 Bufiington July 30, 1940 2,374,336 DArcey Apr. 24, 1945 2,391,898 Hobbs Ian. 1, 1946 2,464,328 Mallory Mar. 15, 1949

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