US3071124A

US3071124A - Diaphragm controlled air flow limiting valve for engine governing

Info

Publication number: US3071124A
Authority: US
Inventors: Thomas F Cramer
Original assignee: Holley Carburetor Co
Current assignee: Holley Performance Products Inc
Priority date: 1958-10-20
Filing date: 1958-10-20
Publication date: 1963-01-01
Anticipated expiration: 1980-01-01

Description

Jan. 1, 1963 T. F. CRAMER DIAPHRAGM CONTROLLED AIR FLOW LIMITING VALVE FOR ENGINE GOVERNING 2 Sheetsdheet 1 Filed Oct. 20, 1958 INVENTOR.

TH OM AS F- CRAMER BY A M% M ATTOR NEYS Jan. 1, 1963 T. F. CRAMER DIAPHRAGM CONTROLLED AIR FLOW LIMITING VALVE FOR ENGINE GOVERNING 2 Sheets-Sheet 2 Filed Oct. 20, 1958 FIG- 2- FIG-3- FIG- 4.

FIG. 5'.

INVENTOR. THOMAS F- CRAMER BY [1/ ATTORNEYS L ,472 PW nitd rates Patent Gfifice This invention pertains to a diaphragm controlled air flow limiting valve for engine governing which is used to control available engine vacuum for establishing the actuating force to govern the engine.

In motor vehicle governing systems, the engine carburetor barrel is provided with a venturi for supplying a speed responsive vacuum to which is metered atmospheric air in an inverse ratio to engine speed so that, as the speed increases, a greater percentage of the venturi vacuum is avialable to actuate the engine governing mechanism. However, with the advent of larger air intakes in modern engine design, the modified venturi Vacuum is insuficient to actuate the governing mechanisms at the desired time.

This invention overcomes this problem by providing a valve which, at the speed to be governed, will move from an initial position to reduce the metered atmospheric air to the venturi vacuum to a very small value so that substantially all of the venturi vacuum is available for actuating the governing mechanism for a short period of time. During this period, the governing function is initiated, and afterwards, when the vacuum condition is at a point where it can control the governing mechanism, the valve of this invention automatically returns to its initial position.

The apparatus for accomplishing this includes a pair of opposed spring loaded vacuum operated diaphragms between which is connected a valve for modifying the atmospheric air to the venturi vacuum. One diaphragm has a smaller area and lighter spring than the other. As the vacuum increases to a predetermined point, the smaller diaphragm will be attracted against its lighter spring to move the valve to a closing position and, as the vacuum further increases, the larger diaphragm will oppose its heavier spring and the smaller diaphragm to return the valve to its open position so that the valve is closed for a relatively short period of time during which the governing function is initiated.

it is therefore an object of this invention to provide an air flow valve which is actuable to change the opening for air flow at a predetermined air pressure and will return the opening to its initial position at a further increment of pressure.

It is an object of this invention to provide an air flow valve which is fluid pressure actuable to reduce the opening for air flow at a predetermined fluid pressure and will return the opening to its initial position at a further increment of pressure.

Another object is to provide in an engine governing system wherein the governing force is derived from an engine vacuum modified by atmospheric air in inverse proportions to engine speed, a valve means for reducing to a very small value the modification of the vacuum by the atmospheric air, in order to initiate the engine governing function and then to return the modification of the vacuum by the atmospheric air at a point where the modified vacuum is sufiicient to operate the governing mechanism.

A further object is to provide in an engine governing system a pair of opposed vacuum responsive spring loaded diaphragms, with one diaphragm being smaller than and having a lighter spring than the other, and with .2 valve means connecting the diaphragms and movable by the diaphragms to restrict the atmospheric air modification of an engine vacuum for controlling the governing mechanism; the smaller diaphragm being movable against its lighter spring at a first vacuum pressure to move the valve in one direction with the second larger diaphragm being responsive to an increased vacuum to move the valve in an opposite direction.

These and other objects and advantages will become more apparent during the description of this invention in connection with the drawings, in which:

FIG. 1 is a side elevational view with portions thereof in cross section of a four-barrel carburetor provided with a governor embodying the invention taken on line 11 of FIGURE 3;

FIG. 2 is a side elevational view with the portions thereof in cross section taken on the plane of line 2-2 of FIG. 1;

FIG. 3 is a bottom view taken from the direction of arrows 3-3 of FIG. 1 showing the four barrels of the carburetor;

FIG. 4 is an enlarged schematic view of valve mechanism of this invention which is also shown schematically in FIG. 1; and

FIG. 5 is a partial elevational view of the lost motion connection between the cone valve and diaphragm shown in FIG. 4.

Referring now to FIG. 1, a four-barrel carburetor 10, of the type referred to above, and having an air intake 12, is sectioned to expose one of the primary barrels 14 and one of the secondary barrels 16. The primary barrel 14 is provided with a restriction or venturi throat l8 and a conventionally operated throttle plate 20 mounted on the shaft 22 which extends through the other primary barrel in which is mounted a throttle plate identical to plate 26. The secondary barrel 16 is also provided with a venturi throat 2.4 and a throttle plate 26 mounted on the shaft 23 which extends through the other secondary barrel in which is mounted another secondary plate.

While a particular four-barrel carburetor is shown for purposes of illustration, it will be apparent that the invention is equally applicable to other carburetor constructions.

A vacuum device 3%), commonly referred to as a governor diaphragm assembly, is mounted on the boss 32 extending from the carburetor throttle body 34. The assembly 39 includes a body 36 formed to provide recesses 38 and 40. The recess it? is covered by means of a flexible diaphragm 42 which is secured to the body 36 by means of a cover member 4-4 formed to provide an air-tight chamber 46 of which the flexible diaphragm 42 forms a wall. The cover member may be secured by any suitable means such as screws 47.

As shown by FIGS. l and 2, the diaphragm 42 has secured to the center thereof in a conventional manner a rod i8 passing through passage 5% in the body 36 and having a laterally extending end 52 pivotally secured to the lever 54 which is rigidly secured to the end 56 of the primary throttle shaft '22 extending into the chamber 38. The shaft 22 is mounted in an anti-friction bearing 39, and a spring 41 is disposed between the bearing 39 and the steel and leather washers 43 and 45 to provide a seal. A tension spring 58 attached between the adjustable pin 60, mounted in one of the holes 62 in the body 36, and the fixed pin 64, secured to the lever 54, tends to hold the primary throttle plate 20 in the open position. An atmospherically vented cover plate 66 may be secured by screws 63 to housing 36, thereby protecting the mechanism within chamber 38.

The orifice 72 at the primary venturi throat 18 and the orifice 74- beiow the primary throttle plate 20 are connected by means of the

passages

76 and 78 having fixed

restrictions

80 and 82 respectively with the passage 84 in the body member 36 and the passage 86 in the cover member 4 which lead to the chamber 46. A passage 88 connecting with passage 84 terminates in an opening in the body 36 adapted to receive a threaded fitting 96.

A secondary throttle diaphragm assembly 124 is mounted at the opposite side of the throttle body 34. This assembly comprises a body 126 having a recess 128 vented to the atmosphere through a plate 136 secured by screws 132 and a recess 134 closed by a flexible diaphragm 136 which is secured to the body 126 by means of a cover 138 formed to provide oppositely disposed

chambers

146 and 14 2 between which the flexible diaphragm 136 forms a movable wall. The chamber 142 contains a compression spring 144 positioned between the cover 138 and the rod 146, which is secured to the center of the diaphragm 136, so that the spring 144 urges the rod 146 upwardly to rotate the lever 14% secured rigidly to the secondary throttle shaft 28 counterclockwise, as in FIGURE 3, and close the secondary throttle plates 26. A conduit 156 extending between the chamber 142 and the

vacuum passages

152 and 154 opening to the primary and

secondary venturi throats

18 and 24 enables primary and/or secondary venturi vacuum to evacuate the chamher 142 and displace the diaphragm 136 downwardly, as in FIG. 1, against the spring 144 to open the secondary throttle 26. The force of the spring 144 is selected so that the secondary throttle plate 26 will be open at any predetermined venturi vacuum.

Located at any desired position on the engine is a governor valve assembly 92 comprising a stationary housing 94 adapted to be mounted on the engine and containing a shaft 96 driven in any suitable manner in proportion to engine or vehicle speed. Mounted for rotation with the shaft 96 is a laterally extending sleeve 98 having a spring 100 mounted within the axial passage 102 in the sleeve by attachment at the end to internally threaded member 164, which is keyed in passage 102. Spring 100 is adjustable axially of sleeve 98 by turning the adjustment screw 106 which is reached by removing the access screw 198. The other end of the spring 109 is secured to the governor weight 110 movable axially within the chamber 112 against the spring 166 and having at the free end thereof a valve 114 adapted to close the orifice 116 when the weight 116 is forced outwardly due to the rotation of the shaft 96 and the sleeve 98 in accordance with engine speed. The engine or vehicle speed at which the orifice 116 will be closed is dependent, of course, upon the adjustment of the spring 100. It is apparent, also, that some other governor valve structure may be employed.

A vacuum balancing air bleed is provided through assembly 92 to a valve assembly 161 (later described) when orifice 116 is uncovered. Conduit 118 between alr intake 12 of the carburetor 1t) and the housing 94 and conduit 122 between the housing 94 and the passage 88 in the body 36 are provided so that when the engine or vehicle is operating at a speed insufficient to close the orifice 116, engine vacuum will draw clean air through the conduit 118, into the housing 94, through the orifice 116 and into the chamber 112, through the passage 102 and the axial passage 12% in the shaft 96 and thence through the conduit 122 to the valve assembly 161. When the engine reaches governed speed, the orifice 116 is closed and the air bleed through conduit 122 is cut off.

As shown in FIGS. 1 and 4, valve assembly 161 has mounted therein

opposed diaphragms

162, 163 which are loaded respectively by

adjustable springs

164, 165 with diaphragm 163 being smaller than diaphragm 162 and spring 165 being lighter than spring 164. Formed centrally in the assembly 161 is a wall 167 having an open ing 168 formed therein through which is inserted a cone 169 which is fixedly connected at one end to diaphragm 163 and has a lost motion connection at the other end to diaphragm 162. As best seen in FIGS. 4 and 5, the left end of cone 169 is provided with a slotted member 171 in which pin 172 rides, which pin is fixed to bifurcated extension 173 of diaphragm 162. The cone 169 as shown is in an open position and rightward movement of diaphragm 163 will move cone 169 and slot 171 right- Wardly over pin 172 without moving diaphragm 162.

As seen, assembly 161 is provided with

vacuum chambers

176, 177 which are connected through conduit 131, to Venturi vacuum passage 202 and manifold vacuum passage 2%. Placed centrally in assembly 161 on either side of wall 167 are

pressure chambers

182, 183 which are connected respectively to threaded fitting 96 through conduit 184, and to assembly 92 through conduit 122,

with the two chambers being connected through the a clearance between opening 168 and cone 169.

The function of valve assembly 161 is to modify the atmospheric bleed through conduit 122 to chamber 46 of the governing mechanism so that at the initiation of the governing function the bleed is reduced to a very small value so that substantially all of the vacuum force is available for actuating diaphragm 42 and, shortly thereafter, the bleed from conduit 122 is returned to chamber ,6 at a point where the vacuum is sufficient to maintain the diaphragm 42 in an actuated position.

This is done in the following manner. As governed speed is approached, the vacuum in conduit 181 increases and the force created by the differential across diaphragm 163 causes the diaphragm and valve 169 to move to the right. The force created by the pressure differential across diaphragm 162 may be greater; however, it is ineffective to move the diaphragm and member 173 to the left because of lost motion at 171 and the higher spring rate of spring 164. As cone 169 starts its travel rightwardly, the clearance between cone 169 and opening 168 is progressively reduced, decreasing the atmospheric bleed of chamber 46, thus moving throttle plate 20 towards closed position and increasing manifold vacuum thereby, further increasing the pressure differential across diaphragm 163. When diaphragm 163 has reached its rightwardmost position, the clearance between opening 168 and cone 169 is at a minimum and substantially all the vacuum developed in passage 84 is available to actuate diaphragm 42. As the vacuum in conduit 181 increases, the force created by the pressure dilferential across diaphragm 162 becomes sufficient to overcome the force of spring 164 and the opposing pressure differential across diaphragm 163 and thereby move the diaphragm to the left causing the conical valve 169 to also move to the left by means of member 173 and pin 172. As valve 169 moves to the left to its initial position, the vacuum system is permitted to function normally.

If desired, of course, all or any part of the structure shown herein may be incorporated into a single, compact carburetor unit adapted for placement in a vehicle engine compartment.

The drawings and the foregoing specification constitute a description of the improved diaphragm controlled air flow limiting valve for engine governing in such full, clear, concise and exact terms as to enable any person skilled in the art to practice the invention, the scope of which is indicated by the appended claims.

What I claim as my invention is:

1. An engine governing mechanism comprising a carburetor body situated on an engine intake manifold and having a barrel With a throttle plate pivotable therein, venturi means being located in said barrel for providing a vacuum, means connected to said manifold for supplying a vacuum, a fluid motor connected to said throttle for actuating same, opposed vacuum chambers separated from connected pressure chambers by spring loaded diaphragms of different areas, with the smaller of said diaphragms having a lighter spring than the larger of said diaphragms, a diaphragm connected cone being inserted through the connection between the pressure chambers, said cone decreasing the connection as the smaller diaphragm is moved against its spring, said venturi and manifold vacuum means connected to said vacuum chambers and to the pressure chamber adjacent said larger diaphragm, means responsive to engine speed for metering atmospheric air in inverse proportion to engine speed to the pressure chamber adjacent said smaller diaphragm, means connecting the aforesaid vacuums and the metered atmospheric air to said fluid motor, said cone being movable by said smaller diaphragm as said venturi and manifold vacuums reach predetermined values to decrease the aforesaid connection, due to the greater pressure drop thereacross as compared to said larger diaphragm, and said cone being movable in a reverse direction as the venturi and manifold vacuums increase and the pressure drop across said larger diaphragm becomes greater.

2. An engine governing system for an internal combustion engine comprising a carburetor having a throttle, a venturi and a manifold, a fluid motor connected to said throttle, passage means connecting said venturi and manifold to provide a source of speed responsive vacuum, speed responsive means for providing a metered source of atmospheric air, and valve means including a variable orifice for connecting the speed responsive metered air and the vacuum to form an actuating fluid pressure for operating said motor, said valve means being movable in response to the attainment of a predetermined value of said vacuum to change the size of said orifice between said vacuum and said speed responsive metered air, said valve means being further movable in response to the attainment of a predetermined decrease change in said predetermined value of said vacuum to return said orifice to its original size.

3. An engine governing system for an internal combustion engine comprising a carburetor having a throttle, a venturi and a manifold, a fluid motor connected to said throttle to close said throttle, passage means connecting said venturi and manifold to provide a source of speed responsive vacuum, speed responsive means for providing a metered source of atmospheric air, and valve means including a variable orifice for connecting the speed responsive metered air and the vacuum to form an actuating fluid pressure for operating said motor, said valve means being movable in one direction in response to the attainment of a predetermined value of said vacuum to decrease the size of said orifice between said vacuum and said speed responsive metered air, said valve means being further movable in the opposite direction in response to the attainment of a predetermined decrease change in said predetermined value of said vacuum to return said orifice to its original size.

4. An engine governing system for an internal combustion engine comprising a carburetor having a throttle, a venturi and a manifold, a fluid motor connected to said throttle for actuating same, means connecting said venturi and said manifold to provide a speed responsive vacuum, speed responsive means for metering atmospheric air, valve means providing a connection between the speed responsive metered air and the speed responsive vacuum so as to form an actuating pressure for operating said fluid motor, said valve means being movable in response to the attainment of a predetermined value of the aforesaid vacuum to change the aforesaid connection between the vacuum and the metered atmospheric air, said valve means beingretnrnable to its original position in response to the attainment of a predetermined decreased change in said predetermined value of vacuum to return the connection to its initial opening, said valve means comprising a pair of opposed vacuum responsive spring loaded diaphragms for moving a valve member, one of said diapbragms having a smaller area and a lighter spring than the other of said diaphragms for moving the valve member in one direction upon the attainment of said predetermined value of vacuum, and said other diaphragm being adapted to move said valve member in the opposite direction upon the attainment of the predetermined decreased change in said predetermined value of vacuum.

5. An engine governing system for an internal combustion engine comprising a carburetor having a throttle, a venturi and a manifold, a fluid motor connected to said throttle for actuating same, passage means connected to said venturi to provide a source of variable vacuum, speed responsive means for providing a metered source of atmospheric air, and valve means including a variable orifice for connecting the speed responsive metered air and the vacuum to form an actuating fluid pressure for operating said motor, said valve means being movable in response to the attainment of a predetermined value of said vacuum to change the size of said orifice between said vacuum and said speed responsive metered air, said valve means being further movable in response to the attainment of a predetermined decrease change in said predetermined value of said vacuum to return said orifice to its original size.

6. An engine governing system for an internal combustion engine comprising a carburetor having a throttle, a venturi and a manifold, a fluid motor connected to said throttle for actuating same, passage means connected to said manifold to provide a source of variable vacuum, speed responsive means for providing a metered source of atmospheric air, and valve means including a variable orifice for connecting the speed responsive metered air and the vacuum to form an actuating fluid pressure for operating said motor, said valve means being movable in response to the attainment of a predetermined value of said vacuum to change the size of said orifice between said vacuum and said speed responsive metered air, said valve means being further movable in response to the attainment of a predetermined decrease change in said predetermined value of said vacuum to return said orifice to its original size.

7. A governing system for an engine comprising a speed control member, a fluid motor operatively connected to said member for actuating same, means in said engine for establishing a source of vacuum which is variable in response to the speed of the engine, speed. responsive means for metering atmospheric air, and valve means providing a variable connection between the speed responsive vacuum and the speed responsive metered air so as to form an actuating pressure for operating said motor, said valve means being movable in one direction in response to the attainment of a predetermined value of the aforesaid vacuum to change the aforesaid connection between the vacuum and the metered atmospheric air, and said valve means being returnable to its original position in response to the attainment of a predetermined decreased change in said predetermined value of vacuum to return the connection to its original size.

8. An engine governing system for an internal combustion engine comprising a carburetor having a throttle, a venturi and a manifold, a fluid motor connected to said throttle, passage means connecting said venturi and manifold to provide a speed responsive vacuum source, speed responsive means for providing a metered source of atmospheric air, and valve means including a variable orifice for connecting the speed responsive metered air and the vacuum to form an actuating fluid pressure for operating said motor, said valve means being operable to change the size of said orifice upon the attainment of a predetermined value of the vacuum.

References Cited in the file of this patent UNITED STATES PATENTS 2,317,271 Higley et a1 .2 Apr. 30, 1943 2,333,805 Matheson Nov. 9, 1943 2,359,231 Mallory Sept. 26, 1944 2,381,429 Bell Aug. 7, 1945 2,431,816 Mallory Dec. 2, 1947 2,664,867 Hartzell Jan. 5, 1954 2,736,305 Kennedy Feb. 28, 1956

Claims

1. AN ENGINE GOVERNING MECHANISM COMPRISING A CARBURETOR BODY SITUATED ON AN ENGINE INTAKE MANIFOLD AND HAVING A BARREL WITH A THROTTLE PLATE PIVOTABLE THEREIN, VENTURI MEANS BEING LOCATED IN SAID BARREL FOR PROVIDING A VACUUM, MEANS CONNECTED TO SAID MANIFOLD FOR SUPPLYING A VACUUM, A FLUID MOTOR CONNECTED TO SAID THROTTLE FOR ACTUATING SAME, OPPOSED VACUUM CHAMBERS SEPARATED FROM CONNECTED PRESSURE CHAMBERS BY SPRING LOADED DIAPHRAGMS OF DIFFERENT AREAS, WITH THE SMALLER OF SAID DIAPHRAGMS HAVING A LIGHTER SPRING THAN THE LARGER OF SAID DIAPHRAGMS, A DIAPHRAGM CONNECTED CONE BEING INSERTED THROUGH THE CONNECTION BETWEEN THE PRESSURE CHAMBERS, SAID CONE DECREASING THE CONNECTION AS THE SMALLER DIAPHRAGM IS MOVED AGAINST ITS SPRING, SAID VENTURI AND MANIFOLD VACUUM MEANS CONNECTED TO SAID VACUUM CHAMBERS AND TO THE PRESSURE CHAMBER ADJACENT SAID LARGER DIAPHRAGM, MEANS RESPONSIVE TO ENGINE SPEED FOR