US1891474A - Carburetor - Google Patents

Description

` Dec. 20, 1932.

R. M. HEINTZ CARBURETOR Filed NOV. 24. 1930 INVENTOR, RALPH M. HEINTZ.

BY /f ATTORNEY Patented Dec. 20, 1932 UNITED STATES PATENT 01u-fictif@```l RALPH M. HnIN'rz, or rALo AL'ro, CALIFORNIA, AssIGNon 'ro Ynnnrrz a KAUEIIAN, 5

LTD., or SAN FRANCISCO, CALIFORNIA, AcoRroRA'rIoIvv oFNnvAnA A 'CAnBURnToR Application iled' November 24, 1930. Serial- No. 497,818.

My invention relates to carburetors for internalcombustion engines, and particularly -to carburetors for engines where the conditions of use make the application of the usual ioat chamberfimpracticable.

Among the objects of my invention are: First, to provide a carburetor adapted to small, high-speed engines of the two-cycle type; second, to provide a carburetor comprising few and simple parts; third, to pro'- vide a carburetor which will supply a proper fuel mixture over a wide range of operating speed; fourth, to provide a carburetor offering low frictional resistance to the flow'gascs;

and fifth, t0 provide a carburetor which will operate from a fuelztank mounted beneath it, and wherein the change of adjustment re'- quired with Changing fuel level in the tank is, in general, unnecessary, and where such change is required it may be easily accomplished. Y

Other objects of my invention will be lapparent or will befspecifically pointed out in the description forming a part of this specification, but I do not limit myself to theaembodiment of my invention herein described, as various forms may be adopted within the Scope of thefclaims. Y

Referring to the drawing:

Figure 1 is a plan view of a carburetor embodying my invention. s r

Figure 2 is an axial Sectional view of the carburetor. y

Figure 3 isatransverse sectional view of I the carburetor, the plane of section being indicated by the line 3-3 of Figure 2. Y

Figure 4 is an axial sectional view of kthe lower portion of the carburetor, the plane of section being perpendicular to that of'Figure 1, asV indicated by the line 4 4 of Figure 3.

Ingeneral terms, the carburetor of my invention comprises a U-shaped Venturi tube` having a fuel -iet opening into the curved por-y tion of the tube. This fuel jet is preferably connected toj a substantially vertical feed pipe, the lower end of which is provided with a foot valve to prevent return flow of fuel. A throttle comprising a diaphragm is mounted acrossl both arms of the U-tube, and is pro- 0 vided with apertures which are preferably yopen.

of the body comprises a plate 5 whichis cirdissimiliar in form, so that the. intake armof the tube is less restricted than the outlet arm when the throttle is nearly closed, both arms being unrestricted when the throttle is wide Describing a preferred form of my'invention inY greater detail, the body of the carburetor comprises two principal parts which are preferably castings. The lower portion cularV in Ageneral form and is provided with apair of projecting lugs 6 for attachingthe upper casting. Depending from Ithe plate area cylindrical flange or skirt 7 and a semitoroidal U-tube 8.- The openings 9 and 10 of the U-tube through the surface of the plate arecircular, but its central portion is somewhat iattened, as indicated by the reference character 12, so that it constitutes a venturi. A short Cylindrical boss 13 projects upward '7 from the center of the plate, and' this boss is drilled vand threaded for the stem 15 of a needle valve. Threaded into the bottom of thel U-tube immediately beneath the needle valve is a fuel pipe 16, into the top of which '15 is fitted a jet 17 which formsI the seat of the Fastened to the lower end of the fuel pipe is afoot or check valve 18 of familiar type, which prevents the return through the valve of liquid-which has once been drawn upward into the pipe. v

The throttle comprises a circular diaphragm 20, which is pivotally mounted upon the boss 13. The diaphragm is provided with two apertures 21 and 22. The aperture 21 vis approximately egg-shaped inform, while the aperture 22 is circular. VThese apertures Vare so arranged that When the diaphragm is rotated so that the aperture 22 coincides with A' the aperture 10, the arc forming the large end of the'egg-shaped aperture 21 also coincides with the 'edge of the opening 9 and both arms of the U-tube are unrestricted.` When the diaphragm is rotated so as to move the apertures 22 and 10 out of alignment, the tapered end of the egg-shaped aperture 21 overlies the` aperture 9. Y This causes the closing of the throttle torestrict the opening 10 of the U- m0 tube more rapidly than the opening 9.

A rim 23 projects slightly above the plane of the plate 5, and partly surrounds the throttle 20, in order to leave space in which the throttle may be moved freely. The rim is cut away on one side to form a rabbet 24 also comprises a substantially circular plate 80, provided with lugs or ears 31'by whichrit is secured to the plate 5 by means ofthe screws32. y 1 j Rising from theplate isa super-structure, roughly like a figure eight in plan, which forms the two rising arms which continue the U-tube. The intake ar1n33 is closed at the top, and is-provided on either side Ywith an opening 35 for admitting' the intake air tothe carburetor. I have found that the use of these opposed openings on the sides of the arm -greatly increases the effectiveness of the carbureting action as compared with the use of a single opening, or with a U-tube open at the top. This is apparently due to increased'turbulence in the airpassing through the carburetor. l

The outlet arm 36 is conveniently of about the same length as the inlet arm, and receives a curved tube 37 whose upper end is provided with a flange 38 to connect with the intake port of the engine. Y

The needle valve 15 passes down through the upper casting between the two arms of the U-tube, and is provided with a handle Ll0 `threaded to its upper end. The threaded portion of the handle is slotted,.as indicated by the reference character 41, and the slot forms a clamp which may be tightened by .a screw 42 to hold the handle firmly in position on the needle valve. The upper end of the valve stem isprovided with-a screw slot 43, which permits thepreliminary adjustment of the valve. This is done by screwing the valve down firmly into its seat in thejet 17, adjusting the handle 40 to the closed position, and then tightening the clamp screw .42.

The needle valve adjustment is held in the desired position by the friction provided by a spring 45 comprising a wire inserted in the r'under part of the handle, and looped around the stem of the valve. 'lhe friction of this spring against the top of the carburetor body prevents unintended movement of thevalve. As the device is ordinarily used, it is mounted directly above theffuelta'nk, which may bein the base of the engine which the -saidU-t'ube and having apertures asymmet-l carburetor supplies. The suction provided by the engine draws the fuel up into the fuel pipe 1G, where it is held by the check valve 18. The arrangements of the dissimilar apertures in the throttle have been found to give the 'proper mixture of fuel and air for all running conditions, without the use of auxiliary jets or other complications.

. Experience has shown that the height of the fuel inthe tank, as long as the variation does not exceed Vapproximately 6 inches, makes practically no difference in the operation of the carburetor. However, with certain grades; ,of .fuel jwhichidemand particularly accurate adjustments, such variation as does occur may readily be compensated by a slight movement of the needle valve. 'In portable engines, for which the carburetor is particularly designed, the needle valve maybe used to cut off thefuel supply entirely when the 85 engine' is not in operation.

,Iclaimz A" i I 1. Acarburetor comprising a U.shaped Venturi tube, a fuel jet entering said tube in the curved portion thereof, and a. throttle 4.950 comprising an apertured diaphragm pivotally mounted between the arms of said Venturi tube and arranged across both armsvof said U-tube.

2. A carburetor comprising a. U-'shaped '55 Venturi tube, a fuel jet enteringsaid tube in the curved portionthereof, and a throttle comprising a diaphragm arranged across both arms of lsaid U'tube and havingldissimilar apertures therein to .cause unequal restrictions in the two arms of the tube.`

3. A carburetor 1 comprising av U-shaped Venturi tube, a fuel jet entering said tube'in the curved portion thereof, anda throttle comprising adiaphragm pivotally mounted between the arms of said U-tube and arranged across both of said arms and having dissimilar apertures therein to cause unequal restrictions in the two arms of the tube.

.4. A carburetor comprising a U-tube havf ing inlet and outlet arms, a fuel jet entering said tube in the curved portion thereof, and a throttle comprising a movably mounted diaphragm arranged across both arms of rically arranged thereinto restrict said outlet arm to a .greater extent than said inlet arm when nearly closed, and to leave both arms unrestricted when open.

4 5. A carburetor comprising -a U-shaped Venturi tube, a fuel jetA entering the conl stricted portion of said tube, a throttle comprising a diaphragm movably mounted across both arms of said tube, a fuel pipe rlsing substantially vertically to said jet, and a footf .valve mounted onsaid fuel pipe toprevent the return of fuel therethrough. y

6. AV carburetor comprising a U-shaped Venturi tube havinginlet and outlet arms,

the end of said inletrarm being closed and an in1et port being formed in the side o said arm, a throttle comprising an apertured diaphragm ivotally mounted between the arms of said enturi tube and movably arranged 5 across both of said arms, and a fuel jet entering said tube in the curved portion thereof. In testimony whereof, I have hereunto set my hand.

RALPH M. HEINTZ.

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