US1790821A - Cabbttbetob - Google Patents

Description

F 3, 1931. M. A. s. LAVIGNE CARBURETOR Original Filed June 11. 1929 ld/@vibra j E n @o .I /W d w Patented Feb. 3, 1.931

PATENT OFFICE MICHAEL A. S. LAVIGNE, Ol' WORCESTER, MASSACHUSETTS CABBURETOR f application niea :une 11, 192e, serial ivo. 370,397. neneivea november 17, 19:10..V

This' invention relates to carburetors for internalA combustion engines, and pertains particularly to features of construction whereby eicient carburetion and control of carburetion is effected.`

One feature of the invention is the relation between the float chamber and'centrally located concentric baiiles, which providethe plurality of concentric air passages upwardly through the body of the carburetor casing.

This feature includes also the particular construction whereby the pipe connection from the float chamber to a central fuel jet provides the supporting strength for holding the central bafes in position;VA Another related feature is the shape of one ofthe upright bailies and particularly the upper end of one of them which is curved over the centra1- most air passage.

Another feature of the invention pertains to the particular shape of the interior of the top dome or cover, and to a eculiarly shaped delecting baie which stands in the path of the fuel mixture after it leaves the initial carburetion.

Another feature of the invention relates to the control of the fresh air and pertains to a particular automatic choke device which is positioned in the carburetor intake pipe.

This device is peculiar in that a spring-held valve plate stands in an open position, normally, when the carburetor or its engine is idle, after which the valve is closed when the engine initially fires and at which'time point of 35 the valve constitutes a positive choke. The

' device is further peculiar in that it is freely yieldable to a wide open position when the engine speeds up, andin this latter position, the valve plate has moved to a position on 40 the op osite side of its seat from that posiltion w ere the plate stood when the carburetor wasnot in use.

and advantages will be described and claimed '45 in the following specification and claims, and

"5o showing the engine end at the upper portion and the fresh air intake with the automatic choke device therein at the lower portion;

Figure 2 represents a sectional view taken Athrough the top manifold cover'and on the line 2 2 of Figure 1; looking downwardly; 55 Figure 3 is a sectional view on the line 3 3 of Figure 1, taken through the main casing and showing the relative position of the air intake passages with respect to the casing wall;'and

Figure 4 is a view of a modification of the automatic fresh air intake valve, which is peculiar in that the valve seat is formed in the intake pipe.

`Like reference characters identify like parts in the several figures of the drawing. Referring in detail to the drawing, 1 is the main casing wall which encloses the ioat chamber and other parts of the mixing apparatus of the carburetor. 2 indicates the 70 cover, which is adapted to be securely fastened to the casing 1, and which has an annular flat plate portion 2, which is adapted to tightlyr` close the upper side of the floatv chamber. At the extreme upper left hand portion of Figure 1 is the discharge opening 3 which is connected to the engine intake manifold and is adapted to be controlled b the throttle valve 4, mounted on the sha 5. At the lower end of the carburetor is the fresh air intake pipe 6, which normally receives fresh heated air from the usual stove connected to the exhaust manifold of an en ine The main bowl or casing 1` is peculiar in 85 that it is cast in one piece and also has the particular feature now to be described. Immediately beneath the floor of the bowl and inline' with the bore of the intake pipe 6, there is an enlarged space 7, through which 90 the incoming air isled upwardly into the body of the carburetor. The above and other additional features ,j

8 indicates the annular float chamber, the

Iouter wall of which is the casing 1, and the inner wall of which is provided by a central 95 upright wall 9, which extends from the floor of the chamber to the fiat plate portion 2, and joins the plate portion with a tight joint as indicated at 9a. On the central side of the wall 9 is a second uprightwall l]0,'and im- 100 mediately at the central portion of the casing is the upright fuel pipe 11', which terminates at its upper end in the `jet opening 11. In Figure 1, 11 is illustrated as formed sepa '5 rately from 11 and screw-threaded to it. It is obvious that jet openings of different sizes may be substituted. where the jet oric'e portion is thus removable. Passageways for incoming air are provided at` 12 between the walls'9 and 10, and at 13 between .the walls 10 vand 11, respectively. The up er end of the wall 10 is extended abovethe evel of the jet opening and 'is turned inwardly and centrally, providing the inwardly projecting flange Fuel from the float chamber 8 reaches the central fuel pipe and its interior bore'14- by passing through a supporting pipe 15, which brid es the central space from one side of the 20 annu ar float chamber to the opposite side.

The i e 15 has a central bore 16, through whic ne fuel flows. The pipe 15 serves also as supporting means for the walls 10 and 11, and msures rigidity of these arts by being anchored at both ends to the ldor of the carburetor bowl and -by being cast in .one piece with thev bowl and with the parts which it thus su ports.' One or more spiral baliles 17- are `positioned in the airspace 13, between the walls 10 and 11, and serve to provide the air with a swirling helical movement twisting upwardly through the passageway 13 and over the end of the jet openingV at 11. One such spiral-.bale 17 is shown in Figure 1 as bridging the space between the walls 10 and 11, and in Figure 3 tw'o baies are shown similar to a double helix one on each side of the center wallll.

.A control valve terminating in a needle 4 point is provided by a rod 181, which projects downwardly through the upper central point of thecover member 2, and which may be adjusted to vary the flow of liquid from the opening at 11, '45, The supply of fuel to the float chamber is led in through a supply pipe 19, which is connected'to the cover member 2. "A needle valve 20 points upwardly and controls the downward flow under the action of an annular loat member 21',-which is hinged at 22 and which carries an arm 23 to engage with the needle valve 20. In Figure 1, the float is shown in its upper position with the arm 23 ,55 raised against the lower end of the needle 20,

thus closing the needle valve against additional intake of liquid fuel. v The walls of thedome-like cover membe 2 are peculiar in that they are spaced outwardly away from the central opening 9 and there is thus the beforementioned-iiat y cover plate portion 2, the under surface of which constitutes the roof for the float chamber and the upper surface of which constitutes the iioor of the dome portion.

Directly across the path of the fuel mixture within the dome, there is a peculiarly shaped deiecting baille 24, which starts at the plate 2 and is curved upwardly n the side next to the outlet opening 3 and away from that inner surface of the dome.

Directly opposite to the deflecting baille 24 is an upright vane or fin 25, which extends as a rib from the'upper part of the dome to 'the floor ,thereof at that portion of the casingl directly adjacent the needle valve 20.- The opening for the needle valve 20 is formed in the enlargement of the cover wall, which results in the projecting in 25.

In the upward movement of incoming air, after it has been mixed with the fuel, the resultantmixture is drawn upwardly striking the under face of the baille 24, and re bounding to the opposite wall of the dome, where it is `divided into two main streams by the projecting lin 25. This construction has resulted in unusual efficiency by reason of the tumbling movement given the gases and the tortuous passage through which they pass.

Referring in detail to the automatic fresh air control valve, in Figure 1, there is shown .a sleeve 26, which has been inserted into the pipe 6 and within which it has a relatively close fit, so as to prevent the passage of air between the sleeve and the pipe. A set screw 27 holds the sleeve in position. On the inner surface of the sleeveis `an inwardly projecting ridge which may be considered the equivalent of a door frame and which is indicated at 28. A disc-like valve 29 isso mounted as to substantially close the o ening of the door frame under certain con itions and must be free to move from one side of the frame to the other. The mounting of this valve 29 includes a slidable rod l30, which is journaled in cross braces/31 and 32, which latter extend across the bore of the .sleeve 26 and are fixed with respect totl1e sleeve. A spring 33, encircling the rod 30, abuts the valve disc 29 on the carburetor side, and normally yieldably holds the valve spaced from the part 28 and on the intake side thereof. A relatively shorter spring 34 prevents the disc 29 from moving too far away from the. part 28 on the intake side and assists in thrusting the valve to the closed po# sition when the suction from the engine or carburetor tends to draw the valve engineward. As shown, the spring 33 is relatively long, as compared to the spring 34, and inl retor is drawn up cludes a larger'number of turns. This device is peculiar because it is set to operate in the following manner. When the carbuon by relatively slow movement of the engine, it is desirable that there be some freedom of movement for air` so as to avoid the dragging action of a vacuum, and hence the valve disc 29is held slightly open. Such a condition exists at the time that the engine is being turned by hand or relatively slowly under the first influence of a starter.

As soon as the initial firing has taken place, in order to prevent the engine from dying and in order to make the mixture as rich as possible, in other words to choke the carburetor, the plate 29 is sucked inwardly to Y a vposition substantially in line with `the part -jecting centrally over t 28, and thus the door is closed and the mixture becomes relatively rich.

As the engine speeds up, it provides a.l

strong suction sufficient to draw the valve wide open on the carburetor side of the part 28, and thus the action is automatic.

A modified construction of the automatic air control is shown in Figure 4, in which the rod 30 has its opposite ends journaled in cross pins 35, which are extended through the intake pipe and fastened by cotter pins or other locking pins 36. In this arrangement, a cam 37 operates against the intake face side .of the valve disc, and under the inuence of some 4connection which may be controlled from the dashsor from the throttle control. For this connection, the cam is mounted on a pin 38, which is journaled in the intake pipe 6, and is subject to the control of a lever 39, which may be connected to the throttle lever of the automobile or other engine on which this carburetor is mounted.

1. In a carburetor, a main outer casing, the wall of which constitutes the outer wall of a float chamber, an upright fuelpipe positioned centrally within said chamber and having a jet opening at its upper end, a plurality of concentric upright walls between the casing wall and said pipe and spaced apart and providing a plurality of concentric air passages between said fuel pipe and said float chamber, the upper end of the wall next adjacent said fuel pipe extendin upwardly and proe air passage about thc fuel pipe and terminating in a reduced openin above and spaced from the jet opening, and a spirally extending baie located in the air passage next adjacent the central fuel pipe whereby air moving upwardly passes over the jet o ening with a revolving motion.

2. In a car uretor, a main outer casing,the wall of which constitutes the outer wall of a float chamber, an upright fuel pipe positioned centrally within said chamber and having a jet opening at its upper end, a plurality of concentric upright walls between the casing wall and said pipe and spaced apart and prothe fuel pipe and terminating in a reduced opening above and spaced from the jet opening, and aspirally extending baiiie located in the air passage next adjacent the central fuel pipe whereby air moving upwardly passes over the jet opening witha revolving motion, and bridging the space between the walls of said air-passage.

3. In a carburetor having a casing providing a ioat chamber and fuel jet opening and an air intake passage positioned centrally with respect thereto, a cover having a lower annular plate closing said ioat chamber and providing a central passageway for the fuel mixture, saidpassageway extending first upwardly and thence laterally to a discharge opening and providing a bend in the inner upper central portion of said cover, the inner wall of said cover above said annular plate extending as an enlarged dome, the lower edge of the wall of which is spaced outwardly from the central edge of said plate, and a deflecting baille located within said cover and extending upwardly from the central edge of said plate and curved corresponding to the curvature of the edge of the plate.

4. In a carbu-retor having a casing providing a ioat chamber and fuel jet opening and an air intake passage positioned centrally with respect thereto, a cover having a lower annular plate closing said float chamber and providing a central passageway for the fuel mixture, said passageway extending first upwardly and thence laterally to a discharge opening and providing a bend in the inner upper central portion of said cover, the inner wall of said cover above, said annular plate extending as an enlarged dome, the lower edge of the wall of which is spaced outwardly from the central edge of said plate, and a deflecting battle located within said cover and on the discharge side of said central passageway and extending upwardly from the central edge of said plate on one side of the central opening and thence curved away from the discharge opening and terminating with an upper edge spaced from the inner surface of the dome. Y

5. In a carburetor-having a casing providing a ioat chamber and fuel jet opening and an air intake passage positioned centrally with respect thereto, a cover having a lower annular plate closing said ioat chamber and providing a central passageway for the fuel mixture, said passageway extending first upwardly and thence laterally to a discharge opening and providing a bend in the inner upper central portion ofnsaid cover, the inner wall of said cover above said annular plate extending as an enlarged dome, the

lower ed e' of the wall of which is spaced out- Wardly om the central edge of4 said plate -and adeecting baile located within sail minating with an' up er edge spaced from the inner surface'of t e dome and conformcover and on the discharge sidecof'said central passageway and extending upwardly from the 'central edge of said late on one side of the central opening andt ence curved away from the discharge opening and ter.-

ing to the curve ofthe inner surface thereof,

the opposite sides of said deflecting ,baille being located respectively on the opposite sides v of said central passagewaly.

In testimony whereof aix my signature.`

MII@ A.

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