US2562936A - Impinging-jet fuel-spray bar - Google Patents

Description

1951 I c. s. MOORE ET AL 2,562,936

IMPINGING-JET FUEL-SPRAY BAR Filed March 1, 1946 Fig. v

Inventors Char/es S. Moore Dav/'0 Nov/Ir A Home Patented Aug. 7, 1951 IMPIN GING-J ET FUEL SPRAY BAR I Charles S. Moore, Cleveland, and David Novik, Shaker Heights, Ohio Application March 1, 1946, Serial No. 651,413

(Granted under the act of March 3,1883, as amended April 30, 1928;. 370 0. G. 757) 4 Claims.

This invention relates to internal combustion engines and in particular to improvements in fuel-air mixing devices foruse in such engines.

In multi-cylinder engines, especially of the reciprocating aircraft type, optimum performance has not always been achieved, due in many cases, to inadequate systems for delivering a homogeneous fuel-air mixture to all of the cylinders. It is recognized that cooling requirements, knocklimited horsepower, fire hazards resulting from backfires, and certain other operational characteristics are related to, or a function of, the fuelair mixture delivered to a cylinder. If the fuelair mixture varies between various cylinders, one, or in some cases several, of the cylinders may place definite performance limitations on the remaining cylinders and hence reduce overall performance below the optimum obtainable when all cylinders receive the most desirable fuel-air mixture. -In general, overall best economy and maximumreliabllityare"obtainable only provided all cylinders function under substantially identical conditions, which again is possible, only provided they receive a fuel-air mixture of optimum characteristics.

One of the objects of the invention is to provide the induction system of a combustion engine with a device which will introduce the fuel in a manner such' that a large area of fuel is exposed to the air flow whereby improved atomization and/ or vaporization occurs.

Another object is to provide a device which deliversgreater quantities of fuel in some portions of the induction air than is delivered to other portionsto compensate for non-uniform fuel distribution which results from bends or turns in an induction system. A further object is to associate a fuel delivery device with respect to a plurality of air throttle valves in such manner that fuel is delivered into an air stream at the point of highest velocity under variable throttle settings.

Various other objects and advantages of the invention will become apparent from the following description, accompanying drawings, and

appended claims. r g

,I t draw s Fig. his a side elevation, partly insection, of one embodiment of the invention;

Fig. 2 is an enlarged perspective of a portion of Fig. 1; and

Fig. 3 is a modified form of the invention illustrated in Fig. 1.

Referring to the drawings, l represents a portion of a. carburetor, or throttle body, for a combustion enginein" which is pivotally mounted a pair of butterfly valves 2, 3. Dotted lines illustrate the closed position of these valves and full lines" a artiany open position. Valves 2 and 3 are linked or geared together to operate in unison and in opposite directions of rotation. One form of connection to operate the valves in this manner is shown by segmental gears l6, IT in Fig. 3.

The numeral 4 illustrates a tube having sets of jets or orifices disposed along its length, these being in pairs having their axes in the same plane and arranged so that the axes of each pair intersect. One set of these jets is shown at 5, 6 and another set on the opposite side of the tube at l, 8. The efiiux of fuel from jet 5 impinges upon the efflux of its companion jet 6 to form a thin fiat fan shaped spray, which presents a, relatively large area of fuel surface to the air flow for atomization and vaporization and hence improves the homogeneity of the fuel-air mixture.

In large engines of the class described it is common practice to employ carburetors or throttle bodies having two or more air tubes, often referred to as choke tubes or barrels. Fig. 1 illustrates an installation whichwould be expedient in a two or four barrel carburetor. Tube 4 is located between, downstream, and parallel to the butterfly valve shafts 9, l0. While Fig. 1 shows only two valves, it will be understood that the installation would be substantially the same with two or more pairs of barrels, the additional pairs being arranged so that each throttle shaft would be extended to pass through the additional barrels.

In a multiple barrel installation as above referred to, the tube 4 could be constructed, in one of its forms, as a generally cylindrical tube having longitudinal grooves or indentations II and [2, the sides of which contain the impinging orifi'ces. Fuel would be supplied to the tube by means of a connection l3 connected to a suitable metering system in the carburetor in any convenient manner well understood in the art.

In many installations it is necessary to connect the carburetor or throttle body to the engine by means of adaptors or conduits which include curved passages through which the fuelair mixture fiows. An adapter of this sort is shown at M, the end remove from its connection with the carburetor being suitably secured to a supercharger casing or other portion of the engine which provides a region of distribution to the individual cylinders. Where a conduit of this type is employed it is not uncommon for a homogeneous mixture entering such conduit to be delivered therefrom as a non-homogeneous mixture due to separation or concentration of fuel particles resulting from centrifugal or gravitational forces. As illustrated, such concentration would be expected in the zone shown at l5, this zone being more rich in fuel than the remainder of the passage through l4. Thisefiect can be corrected by the present invention by proportioning the fuel jets on opposite-sides of the spray tube in such manner that unequal 3 amountsof fuel are delivered thereby. In the embodiment illustrated, the jets 5, B which deliver fuel in the general direction of the outside of the curved adaptor l4 would be proportioned to deliver less fuel than jets I, 8 which deliver fuel in the general direction of the inside of the adaptor. Thus the adaptor [4 would receive fuel I 3 the mixture would render it uniform when it is delivered from the adaptor. The amount of fuel proportioned to the opposite sides of tube 4 would depend on the particular configuration of the adaptor between the carburetor and common distribution region for the individual cylinders. The location of spray tube 4 relative to the butterfly valves forms an important part of the invention. These valves form, in effect, a variable throat venturi, the throat of which, or region of highest air velocity, is at the most restricted zone between the valves. Generally this zone will be, at, or .near a point which is at a minimum distance between the downstream edge of the valves. This can be better understood from a consideration of Fig. 1. In any position other than full throttle where the valves would both be vertical, a portion of the air would flow between the lower edges of the valves and the throttle body. This being a point of restriction would necessarily be a point of high air velocity. The air would then flow around the outside or non-adjacent valve edges and since the flow area is continually increasing downstream the air velocity would be reduced so that adjacent the downstream edge of the valves near the throttle body walls, there would be a region of relative low velocity. On the other hand, the portion of the air flowing between the valves would continue to increase in velocity due to the increased downstream restriction, the point of highest velocity of the air flow across the cross section of the throttle body being in a region between and substantially equidistant from the downstream tip of throttle valves. Atoinization and/or vaporization of fuel is considerably enhanced by locating the spray tube in the high velocity region previously described.

Fig. 3 illustrates another embodiment of a throttle body, primed numerals representing parts corresponding to those of Fig. 1. In this embodiment, the throttle valves 2', 9 are pivoted along one edge rather than at their centers. The body I could be partitioned into a number of cylindrical barrels as in the embodiment previously described, or could be in the form of a single air tube, one form of which could be generally rectangular in transverse cross section. The pivot pointneed not be located completely to one edge as shown but could be between the center of the valve and one edge, that is, having unequal portions projecting from the pivot point. Like the embodiment previously described, this modification would effect a region of highest air velocity downstream and between the adjacent downstream edges of the valves at which point the spray tube '4' would be located.

The principal use of the arrangements previously described are for improved or controlled fuel distribution. The device, however, has utility for liquids other than the main fuel supply to an engine, and it is within the spirit of the invention that they be included accordingly. One example is its use for injecting water or injectedfor the same purpose.

4 water alcohol mixtures or other similar liquids used for the prevention of detonation when the engine is operating at or near its maximum power. Alternately, fuel and water could be Another use would be for priming the engine for starting.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

What we claim is:

1. In a device for mixing fuel and air in the induction system of an internal combustion engine the combination of an unsymmetrically shaped conduit in which the fuel-air mixture ratio is greater along one side than along the other due to centrifugal or gravitational forces, a pair of valves for controlling the airflow through said conduit in such a manner as to form a zone of relatively high velocity in the air passing through said conduit, a tubular fuel conduit disposed at substantially right angles to said conduit in said relatively high velocity zone and downstream from said valves, and a plurality of paired orifices in said fuel conduit disposed in such manner thatthe fuel spray discharged into said zone from one half of each pair of orifices impinges on the fuel spray discharged by the other half of each pair of oriiices, said paired orifices further arranged to discharge fuel substantially downstream and to each side of said zone in unequal amounts whereby a homogeneous mixture of fuel and air flows through said conduit during normal operations.

2. The device as set forth in claim 1 wherein each valve has an axis of rotation disposed intermediate opposite edges.

3. The device as set forth in claim 1 wherein each valve has an axis of rotation adjacent one edge thereof.

4. In a fuel-air induction system having a mixing passage and a throttle means therein, a substantially tubular fuel conduit disposed in said passage at substantially right angles thereto and downstream from said throttle means, two righ angled grooves in the relatively downstream sides of said fuel conduit, a wall of one groove being coplanar with a wall of the other groove on opposite sides of said conduit, and the remaining two walls being parallel to each other and to the axis of said passage, and a plurality of paired orifices in the walls of said grooves disposed in such manner that the fuel spray discharged into said passage from one of each pair of orifices impinges on the fuel discharged by the other of the corresponding pair of orifices.

' CHARLES S. MOORE.

DAVID NOVIK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Mock l Mar. 27, 1945

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