US2255296A

US2255296A - Carburetor nozzle

Info

Publication number: US2255296A
Application number: US248443A
Authority: US
Inventors: James T W Moseley
Original assignee: Carter Carburetor Corp
Current assignee: Carter Carburetor Corp
Priority date: 1938-12-30
Filing date: 1938-12-30
Publication date: 1941-09-09
Anticipated expiration: 1958-09-09
Also published as: GB649920A; FR961987A; BE480774A

Description

P .1. T. w. MOSELEY 2,255,296

CARBURETOR NOZZLE Filed Dec. 30, 1938 I g /1 9 1 (7 I l I 5 [5 l 1 v I r I X 6 IL X l I 7 12 h U 1 i 1 Ii fl l f -7 L|' no.1. i

INVENTOR ATTORNEY JAMES T. W. Moszuzv the transfer point is, generally,

Patented Sept. 9, 1941 James T. W. Moseley,

signer to Carter Carburetor Corporation, St.

Webster Groves, Mo., as-' Louis, Mo.,' a corporation Application December 30, 1938, Serial No. 248,443 Claims. (01. 261-16) This invention relates to carburetorsfor in-H ternal combustion engines and consists, particularly, in novel fuel nozzle construction therefor.

Considerable difliculty'has been experienced by carburetor engineers in designing internal com bustion engine carburetors in which the main fuel nozzle functions satisfactorily when exposed to relatively low suctions, as'at the transfer point when this nozzle starts to supply fuel during opening movement of the throttle and also when the throttle valve is substantially opened and uAccordingly, it is an object of this invention" to provide a main fuel nozzle construction which functions more efiicientl'y at periods of low suc-v tion than other nozzles now in use and which,

at the same time, provides a properly proportioned mixture at other times.

This object and other more .detailed objects hereafter appearing are attained substantially the associated engine is operating slowly due to being subjected to a heavy load. Where the idling or low speed system is interconnected to the main nozzle, as is usually the case in modern automotive carburetors, the mixture supplied at leaner than may be desirable, due to the holding back effect of the idling system. If a so-called eficient type of main nozzle is used, that is,.one in which the axis of the discharge orifice thereof is disposed at an angle of 90 or less to the direction of air flow therepast, more fuel is supplied in the lower suction ranges, but there may be a tendency toward excessive richness at the higher suctions when the associated engine is operating at a faster rate and a relatively lean mixture will sufllce. Onthe other hand, a so-called inemcient type of main nozzle which discharges at an angle against the air stream, maintains the mixture proportions desirably. uniform durin p riods of higher suction, but the discharge therefrom tends to decrease too rapidly in the lower suction ranges; In a'carburetor using such an inefficient typeof nozzle, the fuel mixture supperiods, may be someplied during lower suction what enriched by the use of multiple venturis or by increasing the size of fuel passages through which the main nozzle is fed.

I have found thatthe quality -of-fuel and air mixture supplied byfthe carburetor may be improved, particularly during periods when relatively low suction is applied to the main nozzle, by constructing this nozzle with a main discharge outlet discharging either across or in the general direction of air flow, as in anf'eflcient" type nozzle, as described above, and a substantially I directly above the main. outlet and facing against the] air flow. 'During smaller orifice located periods of low suction, the air sweeps through the tip of the nozzle in a line from the small upper holeto outlet producing a kind the tip of the nozzle itself and, in general, facili tating the duel flow at such times.

by the structures illustrated in the accompanying drawing in which: 4 Fig. 1 is a vertical sectional view showing an internal combustion engine carburetor embodying the invention.

Fig. 2 shows a portion of the structure in Fig. 1 substantially enlarged and Fig. 3 isa-n end view of the main nozzle.

The carburetor illustrated includes a downdraft mixture conduit having air inlet horn l with pivoted choke valve 2, venturis 3, mixing chamber 4, and flanged outlet portion 5 in which is mounted a pivoted throttle valve 6. Adjacent the mixture conduit is a bowl 1 within which fuel is maintained at a substantially constant level X-X by 'fioat 8 and needle valve mechanism 9 .within apertured boss in having a connection I! with aremote fuel tank.

Fuel is supplied to the mixture conduit throiigh a calibrated Jet i2 and-main nozzle it which discharges within the throat portion of the smallest venturl l. Idling fuel is supplied through passages and i5 communicating with the main nozzle-and terminating in idling port It adjacent the edge of the throttle valve, operating with jet I2 is a stepped metering rod I! connected to the throttle valve by pivoted crank 20, link 2|, and lever 22. shown more clearly in Figs.

when closed. (20-- 2 and 3, is of general tubu'lar form and the tip portion thereof has a fuel outlet orifice 23 facing slightly downwardly at an angle, that is, in the general direction of air flow through the mixture conduit, and a substantially smaller hole 24 immediately anteriorv to orifice and facing upwardly, that is, directly against the direction of air flow and so as to direct a to'orifice 24, both being positioned so that air may smooth curve or streamthe larger main of Venturi action within 'flowf therethrough in a gentle curve particularly .during low speed operation.

I have found thatthis nozzle results in materialenrichment of the mixture supplied by the carburetor during periods of low suction, while the mixture supplied during periods of higher j suction and air flow is substantially uniformly proportioned in a desirable manner. Also better portion of the air against the fuel stream in the'nozzle. Lower hole 23 is posterior at an angle as shown or at 90.

gradation of mixture proportions is obtained during transfer of the fueldischarge between the idling and main fuel systems which permits the use of a less efficient idling system. These advantageous results are'apparently due to the fact that at low suctions, air sweeping through the sage, and where a lesser number of venturis are used. Also, the disposition of the main nozzle,

itself, and the size and disposition of hole 24 and orifice 23 may .be varied. The mixture quality may be substantially varied merely by variation of the size and the position of upper hole 24. Orifice 23 may face directly in line with the direction of fiow or it may face across the same The size and positioning of this orifice also are adjustable factors which may be utilized in calibrating the carburetor.

The invention is not limited to the structure shown but may be modified in various respects as will occur to those skilled in the art, and the exclusive use of all such modifications'as come within the scope of the appended claims is contemplated.

I claim:

1. In a downdraft carburetor, an induction conduit provided with a venturi, a constant level chamber, and a fuel nozzl extending upwardly at an angle from said chamber into said conduit and having a tip portion in said venturi, said portion having a fuel discharge orifice and an air inlet orifice, said air inlet orifice facing against the direction of air fiow in said venturi and said discharge orifice facing substantially transversely of said venturi, said orifices being horizontally offset and slightly above the normal fuel surface in said nozzle whereby air entering said inlet orifice may flow acrosssaid surface.

2. In a downdraft carburetor, an induction conduit having a venturi, a constant level chamber, and a fuel nozzle extending upwardly at an angle into said venturi and having a tip portion with an air inlet orifice facing directly against the direction of air flow in said conduit and a discharge orifice facing transversely of said venturi, said orifices being located slightly above the normal fuel level in said nozzle and said air inlet orifice being above said discharge orifice and anterior thereto with respect to the fuel flow in said nozzle whereby air passes through said orifices in a gently curving stream.

, 3. In a carburetor as specified in claim 2 in which said air inlet orifice is small compared to the nozzle bore and said discharge orifice.

4. In a downdraft carburetor, an induction conduit having a venturi, and a fuel nozzle extending upwardly at anangle into said conduit and having a tip portion with a discharge orifice facing transversely of said venturi, said tip portion also having an air inlet orifice slightly anterior to and spaced horizontally of said discharge orifice and facing toward the inlet end of said conduit, said orifice being disposed relative to the normal fuel surface in said inlet during operation whereby air fiows therethrough in a smoothly curved streamline above and across said fuel surface.

5. In' a downdraft carburetor, an induction conduit having a venturi, a. constant level fuel chamber, and a fuel nozzle extending upwardly at an angle into said venturi and having a tip portion with an air inlet orifice facing directly against the direction of air flow in said conduit and a discharge orifice facing across said venturi, said outlet orifice being located slightly above the normal fuel level in said nozzle and said air inlet orifice being adjacent said discharge orifice and spaced transversely thereof whereby air may pass through said orifices and in contact with the fuel in said nozzle during operation.

JAMES T. W. MOSELEY. 1