US3695592A

US3695592A - Plate-type air valve carburetor

Info

Publication number: US3695592A
Application number: US44302A
Authority: US
Inventors: John Quatrano
Original assignee: Bendix Corp
Current assignee: Bendix Corp
Priority date: 1970-06-08
Filing date: 1970-06-08
Publication date: 1972-10-03
Anticipated expiration: 1989-10-03
Also published as: DE2128489A1; FR2096043A5; CA929433A; GB1348551A

Abstract

In a plate-type air valve carburetor having a variable direction air flow, air foil means are provided to compensate for the apparent change in direction of air flow from intermediate to high air flow conditions. As the plate-type air valve aligns itself with the direction of air flow, the upstream edge of the air valve plate encounters the low pressure region below an air foil means and is rapidly snapped or drawn to its full open position. The air foil is positioned sufficiently upstream of the air valve so that its net effect on the apparent direction of air flow is negligible.

Description

[451 Oct.3, 1972 United States Patent Quatrano Bracke....v................. Tubb PLATE-TYPE AIR VALVE CARBURETOR .261/50 A .261/50 A ...261/50 A [72] Inventor: John Quatrano, Watkins Glen, NY.

[73] Assignee: The Bendix Corporation [22] Filed:

Sto1tman.................

1/1957 Udale...................

June 1970 Primary Examiner-Tim R. Miles Attorney-Robert A. Benziger and Flame, Hartz, Smith and Thompson [21] Appl. No.: 44,302

ABSTRACT In a plate-type air valve carburetor having a variable direction air flow, air foil means are provided to compensate for the apparent change in direction of air flow from intermediate to high air flow conditions. As the plate-type air valve aligns itself with the direction of air flow,

[56] References Cited UNITED STATES PATENTS the upstream edge of the air valve plate encounters the low pressure region below an air foil means and is rapidly snapped or drawn to its full open 3 232 315 2/1966 Morelli......................137/484 position. The air for] 1s posltloned sufficiently up- 3,512,508 5/1970 Wmlder...................261/50 A stream of the air valve so that its net effec on the 2,443,464 6/1948 Leibmg et al. ...........261/50 A parent direction of air flow is negligible 3,281,131 10/1966 Mennesson..............261/50 A 2,082,293 6/1937 Linga.......................26l/50 A 2 Claims, 4 Drawing Figures Q P'ATENTEDnm m2 INVENTOR.

Qwfivfiuwt WITNESS ATTORNEY 1 PLATE-TYPE AIR VALVE CARBURETOR BACKGROUND OF THE INVENTION 1 Field of the Invention The present invention is related to air valve carburetors in general and in particular to air valve carburetors which employ a plate-type air valve to provide a signal indicative of the air velocity through the carburetor.

2. Description of the Prior Art The prior art shows that it is well known to employ a plate-type air valve in a carburetor 'to control the amount of fuel being provided to the air stream for ultimate supply to the combustion chambers. of an internal combustion engine. The plate-type air valve carburetors generally employ a flat platetype valve, positioned to block the air intake of the carburetor, resiliently biased to the closed. position. This valve is connected through suitable linkage members to a fuel metering needle and fuel metering orifice such that movement of the valve from the closed to the open position will vary the position of the metering needle within the orifice. This has the ultimate result that a variable supply of fuel, typically gasoline, will be provided to the air stream downstream of the air valve. It has become apparent, however, that a plain tube carburetor intake passage and a flat plate air valve cannotbe combined to provide a smooth variation infuel and air flow, particularly at idle and part throttle operation. The specific problem encountered is that as a flat plate-type air valve begins to open, the first few degrees of angular rotation produce a very large percentage change in the unobstructed air flow path in the carburetor intake passage. It is, therefore, necessary to vary the fuel delivery over a wide range during the first increments of valve movement and it is very difficult to achieve accurate control since slight variations due to manufacturing tolerance or the like will cause large percentage variations in the fuel delivery. It has accordingly been determined that the contour of the intake passage in the vicinity of the plate-type air valve and the contour of the air valve itself may be altered somewhat to provide the necessary smooth and accurate variation of fuel flow in response to air flow. It thus becomes possible to provide a proper air fuel mixture over a broad range of operating conditions of the engine from the idle state to wide open throttle.

The use of the contoured air passage and contoured air valve has generated another problem which becomes apparent only at the wide open throttle setting; As the air valve begins to approach the wide open position, which should be indicative of a high demand for fuel and air the apparent direction of air flow past the air valve tends to be at some angle to the real axis of the air passage due to the contours which were added to smooth out low air flow operation. In those engine demand situations calling for increased fuel and air delivery to the engine, the air valve, having assumed a position which corresponds to a part throttle setting, will not open to the position which will provide the maximum fuel delivery. In the transitionfrom the fully closed to the wide open throttle position, the air valve will assume some position corresponding to air flow at a part-throttle setting and will not, from that time forward, respond to increases in the velocity of air flow invention to provide a means for urging the air valve beyond its nominal wide open setting into a true wide open setting corresponding with themaximum air flow through the air passage of the carburetor. Furthermore, variations in air flow direction may occur from the geometry of the associated air cleaner or the configuration of surrounding masses of engine, vehicle body and the like. It is, therefore, a still further object of the present invention to provide a means for urging an air valve to a wide open position when changes in direction of the moving air stream otherwise prevent such movement. In addition, linkage modifications would introduce an undesirable hysteresis which would adversely affect the accuracy of the angular positioning of the plate-type air valve. It is, therefore, an object of the present invention to provide a means to correct the angular positioning of the plate-type air valve such that the angular positioning of the air valve and the accuracy of the fuel metering are unaffected by hysteresis. It is a further object of this invention to provide a means for opening the air valve from its previously described maximum position to a position which corresponds with the fuel demand of the engine at maximum air flows.

The problem of achieving proper positioning of the air valve in response to air flow is also encountered in another area. As engine sizes increase, air flow demands increase and the cross sectional area of the air intake passages increases. In order to reduce the height of carburetors, the air intake passages are kept as short as possible in order to conform with todays automotive design standards of having a low profile of the vehicle. However, when the plate-type air valve having the necessary large surface area is rotated into alignment with the air flow, its dimension in the direction of air flow is sufficiently large that the air valve extends well into the mouth, or intake, of the carburetor air passage at one end while the downstream edge of the air valve extends well down into the interior of the carburetor body. Thus, a significant portion of the plate-type air valve, which performs most beneficially in regions of laminar flow, must extend into the region of turbulent air flows at the carburetor air intake. The result of this condition is that the air valve is prohibited from responding to the full spectrum of air flow variations. It is, therefore, a further object of this invention to provide means for improving plate-type air valve response to maximum and near maximum .air flows without adversely affecting fuel metering capabilities and without significantly increasing overall height of the carburetor.

SUMMARY OF THE INVENTION The presentinvention provides a plate-type air valve carburetor with an air foil positioned near the intake of the air passage so as to provide a zone of low pressure into which the extreme upstream or leading edge of the plate-type air valve may travel upon its opening rotation. By providing the stationary air foil, the operation of the plate-type air valve is not affected until the air valve begins to enter the nearly wide open position, at which point the prior art variable-direction air flow air valve carburetors had reached their maximum capability in fuel metering. Because the air foil is within the air stream at an extreme of the physical limitations upstream position, it has no overall effect upon the .air

flow characteristics of the carburetor. The air foil can be further restricted in its size so as to have no effect upon the air valve until the air valve begins to approach the position which was a maximum for the prior art air valve carburetors. The air foil, therefore, is operative to affect the angular position of the plate-type air valve with respect to the axis of the air intake passage over the full range of variations thereby permitting complete control of fuel metering within the air valve carburetor without affecting the metering and linkage characteristics. Furthermore, the physical height of this type of carburetor, when mounted atop the engine as is the U. S. automotive practice, can be maintained as low as possible due to the fact that the upper edge of the air valve, as it nears the region which would expose it to the atmospheric air, comes into the influence of the air foil.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 shows my invention as applied to a plate-type air valve carburetor having a contoured air intake and a contoured plate type air valve.

FIG. 2 shows a fragmentary view of the air valve approaching the part throttle position as it approaches the region influenced by the air foil.

FIG. 3 shows in the second fragmentary view the air valve at the wide open throttle position with the air valve under the influence of the air foil.

FIG. 4 shows an elevational view of the air foil of FIGS. 1, 2 and 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIGS. 1, 2 and 3 and particularly to FIG. 1, my invention is illustrated as applied to an air valve carburetor, indicated generally as 10, having a body 11. The carburetor is comprised of air passage 12 extending through body 11 and fuel supply means 14 associated therewith. Fuel from supply means 14 is introduced into the air passage 12 via fuel supply conduit 16. Situated near the intake of air passage 12 is the air valve 18 which is shown as a contoured plate and is attached for angular movement about shaft 20. As illustrated in FIG. 1, the air valve is in the fully closed position preventing air flow through conduit 12 and regulating the fuel supply means so that there is no fuel flow through the fuel conduit 16. Air valve 18 is interconnected with fuel supply means 14 through suitable linkage means, not shown, such that the fuel delivery therefrom is metered and controlled in response to the air valve position.

Air valve wide open assist means indicated generally by 21 are shown in FIG. 1 as being an air foil 22 positioned upstream of the air valve 18. Air foil 22 is illustrated in this embodiment as being a stationary air foil of conventional design and is sufficiently small to present a negligible restriction to total air flow through the intake passage 12. Air foil 22 is attached by conventional means, shown as bolt 23, to support 25. Support 25 is adapted to position air foil 22 in an intercepting relationship with the upstream edge 24 of air valve 18 when air valve 18 is rotated to its open position. The foil is, of course, somewhat upstream of this position as direct physical contact is not desired but rather it is desired that the upstream edge 24 of air valve 18 will intercept the low pressure region 26 normally associated with an air foil in a moving stream of air when the air valve 18 approaches wide open position.

It will be seen that air intake passage 12 is provided with

various contours

28, 30 such that the direction of air flow through conduit 12 will vary from the mouth of passage 12 to the region below the fuel conduit 16. This variation, along with the contour in the plate-type air valve itself, is operative to provide the necessary smooth transition in fuel/air mixture flow from idle operation to the part throttle operation. The prior art devices were substantially limited in their wide-open throttle position to that shown in phantom lines in FIG. 1 as a result of the air valve attaining this position at part throttle operation and increased air demand being supplied by that portion of the air intake passage 12 to the right (relative to FIG. 1 of the drawing) of the air valve pivot. Furthermore, the air being drawn through the air intake passage 12 will, due to the contour at 30, establish a laminar flow characteristic to the right (relative to FIG. 1 of the drawing) of the air valve pivot. This laminar flow will spread to fill the entire intake downstream of the air valve establishing a pressure balance across the downstream portion of the air valve which will prevent, in the absence of my invention, further opening movement of the air valve.

FIG. 2 illustrates, in a fragmentary view, the air valve portion of the air intake 12. In this figure, air valve 18 has rotated counterclockwise in response to the passage of air through intake passage 12. A low pressure region 26 has formed downstream of the air foil 22 but due to the relatively slight velocity of air passing through intake passage 12, the region 26 is small and the upstream portion of valve 18 is not sufficiently close to region 26 to be influenced thereby. The air valve in this figure is approaching the position corresponding to part throttle operation.

FIG. 3 illustrates the FIG. 1 embodiment as the air valve 18 reaches the position corresponding to wide open throttle. The region 26 has grown in size while rotary movement of the air valve 18 and shaft 20 has brought the upstream edge 24 of air valve 18 into the region 26.

FIG. 4 shows an elevational view of the air foil 22 of the present invention. Air foil 22 is shown as an elongated inverted isosceles triangle attached by suitable means, such as bolt 23 through a portion in proximity to the central portion of the base thereof to support 25. Thus the downward pointing apex of the triangle extends downwardly into the interior of passage 12 (shown in FIGS. 1, 2 and 3). This shape of air foil is particularly suited to an air valve having a dimension along its axis in excess of the dimension perpendicular to the axis to the upstream edge of the air valve. By placing the apex generally downstream from the base of the triangular air foil, the influence of the air foil on the air valve will increase as the air valve approaches the air foil. Conversely, as air flow through passage 12 decreases, the influence of the air foil on the air valve will be less pronounced and the air valve will more readily assume a position remote from the air foil to properly reflect the need for fuel to be metered in accord with optimum engine operation.

The operation of my device will now be described with reference to FIGS. 1, 2 and 3. Initially, the air foil 22 will be in the position illustrated by solid lines in FIG. 1. This corresponds to the closed position at which time there will be no fuel flow through the fuel conduit 16. Upon cranking of the associated engine, air will be drawn through the air intake passage 12 by the ordinary action of the cylinders and intake valve opening and closing. This flow of air will create a low pressure region downstream of the air valve 18 and will cause, through the differential area and differential pressures, the valve to pivot about pivot 20 in a counterclockwise direction. This opening movement of the air valve 18 will initiate a fuel flow through conduit 16 in the conventional fashion of air valve carburetors. This fuel flow through conduit 16 is a function of the angular position of the air valve 18 with respect to its closed position (as illustrated in solid lines in FIG. 1). As the air valve approaches the position illustrated in FIG. 2, the engine will be in the part throttle operational mode. That is to say that the engine will be operating at an intermediate power setting and will be demanding fuel and air in substantially the relationship provided by the angular position of air valve 18 and the unrestricted flow area provided within the conduit 12. As can be seen at this point, the air foil 22 is disturbing the flow of air upstream of foil 22 but this turbulence in the air stream is not communicated to the downstream side of air valve 18 due to the fact that air valve 18 is in a substantially blocking relationship across this portion of air intake 12. During this phase of operation the fuel supplied in accord with the air valve setting will be sub stantially as required by the engine through the conventional metering linkage (not shown). As the air, and consequently the fuel, demanded by the engine increases as a result of increased engine speed, the air valve will pivot counterclockwise, relative to FIG. I, a more fully open position as illustrated in FIG. 3. However, in the prior art devices of this type, the air valve would reach a substantially balanced position at which point in time due to the curvature of the intake passage 12 and the curvature of the air valve 18, the air valve would be axially centered relative to the direction of flow of air through the intake passage and further increases in the flow of air would not operate to increase the flow of fuel through conduit 16. In the prior art devices of this type, this corresponded to a maximum fuel setting which was somewhat below that necessary to permit the engine to achieve its maximum power capabilities. It is at this point in time where my invention becomes applicable.

With specific reference to FIG. 3 it will be observed that as the air valve 18 approaches a more fully wide open throttle position, the upstream edge 24 thereof approaches the low pressure region associated with air foil 22. As is known, the amount of and the extent of the low pressure region associated with an air foil in a moving stream of air is a function of the velocity of that stream of air with respect to the air foil as well as the curvature of the foil. As the amount of air being ingested by the engine through intake passage 12 increases in volume, it will increase in velocity. This will produce a continuing increase in the size of the low pressure region which is illustrated by number 26. By suitable design of the size, shape, and physical placement of air foil 22 within intake passage 12, the exact point at which the edge 24 of air valve 18 enters the low pressure region 26 can be varied. At this point In time,

a pressure differential will exist between the upstream portion of air valve 18 and the downstream portion of air valve 18 such that an additional counterclockwise torque will be generated on air valve 18 to rotate it towards the more fully wide open position. The restriction which is presented to the flow of air through air intake 12 will not vary beyond this point; however, the linkage which controls the amount of fuel being provided through conduit 16 will be informed of additional counterclockwise movement which will in turn increase the flow of fuel through fuel conduit 16.

Iclaim:

1. In combination with a carburetor of the type having fuel supply means, a body, an air intake passage passing therethrough and an air valve situated therein to control the delivery of fuel to an air stream, wherein the air valve is a plate-type air valve adapted to rotate about a pivot into substantial alignment with the axis of the intake passage in response to air flow therethrough whereby an edge of the air valve will move from a position in proximity to a wall of said intake passage to a position upstream of the pivot, the improvement comprising:

air valve assist means situated in the air intake passage upstream of the air valve operative to assist movement of the air valve to the maximum open position including air foil means coupled to the air intake passage operative to generate a low pressure zone within the air intake passage in intercepting relationship with the upstream edge of the air valve when the air valve is in the maximum open position.

2. In combination with a carburetor of the type having fuel supply means, a body, an air intake passage passing therethrough and an air valve situated therein to control the delivery of fuel to an-air stream, wherein the air valve is a plate-type air valve adapted to rotate about a pivot into substantial alignment with the axis of the intake passage in response to air flow therethrough whereby an edge of the air valve will move from a position in proximity to a wall of said intake passage to a position upstream of the pivot, the improvement comprising:

air valve assist means situated upstream of the air valve operative to assist movement of the air valve to the maximum open position including means for generating a low pressure zone within the air intake passage in the region of the upstream edge of the air valve and said means for generating a low pressure zone comprising air foil means attached to the housing and positioned at the mouth of the air intake passage so that a low pressure zone will be generated thereby in an intercepting relationship with the upstream edge of the air valve.

Claims

1. In combination with a carburetor of the type having fuel supply means, a body, an air intake passage passing therethrough and an air valve situated therein to control the delivery of fuel to an air stream, wherein the air valve is a plate-type air valve adapted to rotate about a pivot into substantial alignment with the axis of the intake passage in response to air flow therethrough whereby an edge of the air valve will move from a position in proximity to a wall of said intake passage to a position upstream of the pivot, the improvement comprising: air valve assist means situated in the air intake passage upstream of the air valve operative to assist movement of the air valve to the maximum open position including air foil means coupled to the air intake passage operative to generate a low pressure zOne within the air intake passage in intercepting relationship with the upstream edge of the air valve when the air valve is in the maximum open position.

2. In combination with a carburetor of the type having fuel supply means, a body, an air intake passage passing therethrough and an air valve situated therein to control the delivery of fuel to an air stream, wherein the air valve is a plate-type air valve adapted to rotate about a pivot into substantial alignment with the axis of the intake passage in response to air flow therethrough whereby an edge of the air valve will move from a position in proximity to a wall of said intake passage to a position upstream of the pivot, the improvement comprising: air valve assist means situated upstream of the air valve operative to assist movement of the air valve to the maximum open position including means for generating a low pressure zone within the air intake passage in the region of the upstream edge of the air valve and said means for generating a low pressure zone comprising air foil means attached to the housing and positioned at the mouth of the air intake passage so that a low pressure zone will be generated thereby in an intercepting relationship with the upstream edge of the air valve.