US2681216A - Slotted jet carburetor - Google Patents

Description

June 15, 1954 H. KNEcHT TTTTTTTTTTTTTTTTTT OR Patented June 15, 17954 UNITED STATS NT GFF ICE SLOTTED JET CARBURETIOR Henry Knecht, Toledo, Ohio Application April 10, 1951, Serial No. 220,254

2 Claims.

My invention has to do with delivering liquid fuel to an internal combustion engine. The invention, particularly, involves means for introducing liquid fuel from a source into the air within a fuel and air duct connected to the intake manifold on an internal combustion engine.

The invention provides a carburetor of the slotted tube type. The Bennett Patents Nos. 927,211 and 1,673,136 show tube type carburetors and the Shaff Patent No. 2,156,128 shows a slotted form of tube type carburetor. My main purpose in making the invention here described is to provide an even better fuel carburetor than those shown in the mentioned patents.

The chief fault with these prior art constructions resides in the fact that they overcharge the inta-he manifold air with fuel. In other words, they produce excessively "wet charges. Consequently, there will be undesired fuel puddiing and condensing out of fuel portions in the air stream before the charge ever reaches the engine firing chamber. These puddled fuel portions become waste and lost. So, in these prior art constructions the efficiency in fuel use is low and the cost of motor operation high.

I propose to correct these faults with my invention. Also I propose to provide a jet carburetor by which motor operation costs may be lowered considerably. Still further, with my invention, smoother motor operation will be obtained. that by my invention the fuel charge or ratio of fuel to air moving to the engine will vary automatically with the Work load of the engine.

This will give steady increasing or decreasing f power as the demands on the motor vary.

To accomplish these broad goals, my invention has for amore particular object to provide a fluid fuel conduit element for disposition in and across an air duct connected with an engine intake manifold. The element is characterized by the fact that it has two lateral walls in angular relation to each other with their proximating edges spaced to form a slit-like passage between, the opening or mouth of which is in plane with one surface only. More specifically, my invention proposes that one of the lateral walls mentioned shall extend inclinedly to the longitudinal axis of the duct and to the path of the air stream therethrough. The other lateral wall, which is in plane with the mouth of the opening, shall extend in the lee of or the cove formed by the first lateral wall with reference to the mentioned air stream.

By this provision, the passageway through the Of greatest importance will be the fact duct diminishes in cross-sectional area as it progresses downstream-ward along the inclined lateral wall of the charger. As a consequence, the

ir stream portion passing between the charger lateral wall and the duct wall moves with gradually increasing velocity to cause a rapid movement of air in the vicinity of the mouth of the mentioned slit-like passage between the charger lateral walls. The rapid movement of air in the vicinity of the. mouth opening produces an aspiration effect with air rarefaction in the passage. This reduced air pressure incident to rarefaction is communicated to within the conduit element and draws fuel from its source to flow into the conduit element. From there it flows through the passage into the intake duct for transmission to the engine.

A still further and even more particular object of my invention is to provide a jet carburetor of straight tubular form having substantially triangular shape in cross section with one of its lateral walls corresponding to the base of the triangle, disposed most proximate the duct outlet. In addition, such triangular tube jet is designed to have a pair of slit-like openings, each extending along substantially the entire length of lines parallel to the vertices at opposite edges of the mentioned lateral wall. By reason of such triangular shape of the tube jet and its disposition so that its triangle apex edge points in an upstream direction, relative to the air ow through the duct, the air passageway through the duct will be gradually diminished in cross-sectional area between the tube and duct walls. The air as it passes therebetween increases in its velocity. This tends to produce air rarefaction in zones adjoining and Within the slit-like openings, with the resultant fuel in-drawing mentioned before.

The invention consists in other features and advantages which will appear from the following description and upon examination of the drawing. Structures containing the invention may partake of different forms and still embody the invention. To illustrate a practical application of the invention, I have selected a slotted jet carburetor as an example of the various structures and details thereof that contain the invention. I shall describe the selected structure hereinafter. It is understood that variations may be made without departing from the spirit of the invention. The particular structure selected is shown in the accompanying drawing and described hereinafter.

Fig. 1 of the accompanying drawing illustrates a longitudinal section of an air and fuel duct connected to the intake manifold and having a slotted jet carburetor embodying my invention mounted therein. Fig. 2 illustrates a View of an enlarged section taken along the plane of theline 2 2 indicated in Fig. 1. Fig. 3 is a diagrammatic illustration showing, by various hereinafter described symbols, the slotted jet carburetor of Figs. l and 2 in operation.

The drawing shows at Ill an extension of the intake manifold for an internal combustion engine (not shown). The extension Iii is conventional, having an inlet II and outlet l2 and a duct I3. An air stream flows through duct i3 in the direction indicated by arrow it, because of motor action (velocity head) or a supercharger in the line.

The quantity of air allowed to now and thusthe speed of air through the duct I3 is controlled by a throttle valve I6. e. choke valve,

at I5, cooperates with the throttle valve. Preferably, both valves are the unbalanced type, that is with their operating rock shafts i5R and EER ofset from the center of mass and action of the valve venes or faces IV and ISV. rThe choke valve I5 particularly is unbalanced in this sense so as te be sensitive and respond to small changes in the velocity head exerted by the motor because of changes in motor speed on changing motor load.

Another advantage of using the unbalanced type valve I5 is that in Erst opening, the flow of air past the valve is restricted to that occurring immediately adjacent the inner surface of duct wall Il. Flow in this region is particularly advantageous in connection with carburetor action to be described.

The manifold extension l@ also supports a liquid fuel reservoir or bowl 2Q. Flow of fuel from a tank (not shown) to the bowl 2i) is controlled by a iioat 2! in a manner known to the art. The bowl has a cover 22 having a three-way passage 23. rEhe passage way 23a communicates with the bowl interior, way 23h with the atmosphere exterior of the bowl and way 23e with an opening 25 in the duct wall I'I. The passage .fg

ways 23a and 23h are aligned and provide bearing for a hollow metering rod 2S. The rod may be raised or lowered by suitable mechanism, including the link 21, under control cf the engine operator. of registration between the inner end of passage way 23e and an opening 23 communicating with the inner chamber 29 will be varied. By decreasing registration between them, the freedom of passage from inside the bowl 2li to the opening 25 reduced and fuel ow diminished. On

the other hand, increased registration of opening 23 with passage way 23e will allow increased u l flow. lt is intended that the movement of .he rod 26 to vary fuel flow will be synchronized with opening and closing of the throttle valve This practice accords with that of the art, and the means for effecting it is well known.

The fuel allowed by the rod 2E to flow through the passage way Etc enters a fuel charge.` enlbodying my invent-ion. ln the form shown, the fuel charger is a slotted jet tube 30 extending straight between its two opposite ends, 361C and 361'. The end Sr preferably fits within the opening 25 in the wall il of the duct I3 to join in communication with the passage way 23o. The end Silk is closed and preferably bears in an opening 25d in a duct wall opposite the opening 25. A suitable plate 25p affixed to the exterior of the manifold extension I0 serves to close As the rod 26 is moved, the degree u.

4 the open end 30k of tube 30 and lock the tube in position within the duct I3.

t will be seen that the position of the tube 3l! in the duct I3 is such that the tube central longitudinal axis extends normal to and crosses the central longitudinal axis of the duct. Notice should also be taken that the tube 30 extends iineally into the duct from a point on the wall il along which air, on initial opening of choke valve I5, rst moves. It also should be remarked that the tube Se extends in a plane above the level 207e of the fuel in bowl 20. Except that the fuel is moved from the bowl 20 to the tube, as explained later, the tube 30 will remain dry.

The tube 3@ is preferably of an approximate 'triangular shape in cross section (Fig. 2). ts angularly related lateral walls 3l, 32 and 33 are so nearly alike in dimension that the section of the tube 3@ may be said to be equilateral. The wall 3l is more proximate the outlet I2 of the duct i3 than the walls 32 and 33. With reference to the air stream direction, indicated by the arrow it, the wall 3i is on the downstream side of tube 3% and in the lee of or cove provided by the walls E2 and 33. In construction shown, the wall 3l extends across the duct I3 and is normal both laterally and longitudinally to the duct central longitudinal axis.

The walls '32 and 33 meet in angular relation to forni an apex 345 pointing upstream or toward the duct inlet ll. The walls 32 and ,33 extend longitudinally in normal relation to the duct centrai longitudinal axis but in their lateral extension are inclined to such duct axis. Thus the air stream passage through the duct I3 by reason of walls 32 and t3 gradually diminishes in crosssectional area. This causes the air stream moving between the walls 32 and 33 and the walls of the duct I3 to increase in velocity. This increase gradual as the air stream passes through the region within the duct between the apex 34 and edges 32e and 33e of the walls 32 and 33 of the tube 3%.

Referring back again to Fig. 2 of the drawing,

'all 3l is shown to be laterally shorter than the distance between edges 32e 33e of walls 32 33, respectively. rlhe edge SHC of wall 3! is spaced from the edge 32e to form a slit-like pasc between them. Edge 3U is spaced from edge 33e to form a similar passage 38s.

The slit-like passages 3370 and 3cr each have an exterior opening or mouth 38km and 'rm reectively. The span Vof the mouth openings extends in plane with tice wall 3l, as will be seen from Fig. 2 of the drawing, and in the lee of the edges 32e and 33e of walls 32 S3, referring to the air stream in the duct I3. This relation of the passage opening I have just described, I consider to be critical in obtaining the most satisfactory operation of construction embodying my invention.

By reason of this relation, the air at increased velocity by reason ofthe crowding effected by the walls 32 and 33 of the tube ,Sil and duct i3, upon reaching the wall edges 32e and 53e moves normal to the plane of wall Si and the mouths 38km and 381m at great speed into the Zone (marked Z in Fig. 3) downstream of wall S I. rEhe rush of air normal to the span of the mouths and draws air from within the mouths and their conn necting passages :lille and 3ST into the duct I3. This produces air rarefaction (R in 3) in the mouths, passage ways andinterior of the tube 3i). rThe decrease in air pressure as a consequence of rarefaction allows liquid fuel from bowl 2o to move up through the chamber 29 of rod 26 and into tube 39. From there the fuel, still responding to air pressure differentials created as described, lows through passages 38k and 381 out into zone Z (Fig. 3) between the wall 3i and the duct outlet l2. In Zone Z there exists some turbulence of air which eiects desired intermixture of air and iuel particles to compound a propel' fuel charge mixture for the engine. From that point the charge is drawn to the outlet l2 as controlled by throttle valve i6 and then to the engine firing chamber.

Those skilled in the art will observe the existence here of ideal conditions for fuel atomization. For one thing, the arrangement provides injection of fuel stream at right angles into the air stream of high velocity. Second the air and fuel almost immediately enter a zone in which a high degree of turbulence exists.

It will be also noted that the effect of spacing the edges 31k and 3,51' from edges 22e and 35e is such as to produce passages 36k and 38T extending longitudinally, substantially the entire length of the tube 39. As a consequence distribution of the fuel entering the duct l 3 extends over a wide range, from duct wall to duct wall.

By relating the portion of tube 3B most proximate the bowl 2i) at a point on duct wall il, advantage is taken of the eiect produced by the air stream which iiows along Wall l'l on initial opening of the choke valve l5. The :dow of air along the wall exerts the pressure effects described at a point on the tube 3i! where relief thereof can only be had by upward fuel ow from the bowl. As

the valve l5 progressively opens. the air stream controlled thereby encompasses and flows about portions of the tube 36 progressively remote from the bowl 29. Since all the tube portions more proximate to the bowl 2i! are then being subjected to air stream pressure effects, there will be no diminution of fuel flow. Instead there will be proportionate increased flow and distribution.

Thus I provide a slotted jet carburetor by which fuel may be atomized and its density in the charge automatically controlled. As a consequence, an engine provided with a carburetor embodying my invention will tend to operate more smoothly and efficiently.

While I have illustrated and described the best forms of my invention now known to me, as required by the statutes, those skilled in the art will readily understand that changes may be made in the disclosed construction without departing from the spirit of my invention as set forth in the appended claims.

I claim:

1. Means for introducing liquid fuel from a source of fuel into the air within a fuel and air intake duct of an internal combustion engine comprising a conduit element having a pair of adjoining angularly related hat walls and adapted for mounting within the duct between the duct inlet and outlet with one wall extending across the duct in baiiie relation to air current therethrough and the other wall. in the lee of the first wall with respect to said air current; the near edges of the walls being in spaced apart relation to forni a slit-like passage therebetween having its opening in plane with the mentioned lee wall only; and the conduit element having an open end for connection with a source of fuel whereby air passing through the duct is diverted by the baiiie element wall to generate a zone of air rarefaction adjoining the slit-like passage and its opening tending to draw fuel from within the conduct eiement through the slit-like passage into the air of the intake conduit.

2. In an intei'nal combustion engine carburetor having an air conducting passageway there through in communication with the engine intake manifold, a fuel feed bar for introducing liquid fuel to said passageway comprising a tube body having three flat sides and being in a lineally extending relation across said passageway from one to the other side thereof with one said flat side in a plane parallel to and facing toward the passageway outlet and the other flat sides inclined to and facing the passageway inlet; said outlet facing fiat side having a pair of parallel slit openings in communication with the tube body interior; the tube body having open end for connection with a source of liquid fuel; and each of said parallel slit openings having its mouth in plane with said outlet facing fiat side along an edge of the inlet facing fiat side most nearly proximate the outlet of said passageway.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,456,502 Hartwell May 29, 1923 1,816,756 Whatmough et al. July 2S, 1931 1,893,920 Winield Jan. 16, 1933 1,974,286 Monosmith et al. Sept. 18, 1934 2,573,093 Burson Oct. 30, 1951 2,615,696 Winkler Oct. 28, 1952 FOREIGN PATENTS Number Country Date 457,922 Germany Mar. 27, 1928

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