US2862487A

US2862487A - Carburetor throttle mechanism

Info

Publication number: US2862487A
Application number: US616529A
Authority: US
Inventors: Olson Elmer
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1956-10-17
Filing date: 1956-10-17
Publication date: 1958-12-02
Anticipated expiration: 1975-12-02

Description

Dec. 2, 1958 E. OLSON 2,862,487

CARBURETOR THROTTLE MECHANISM Filed Oct. 17, 1956 :s Sheets-Sheet 1 v IN VEN TOR. 67/2267 0/5022 A T TORNE Y Dec. 2, 1958 E. OLS ON 2,862,487

CARBURETOR THROTTLE MECHANISM Filed Oct. 1'7, 1956 Sheets-Sheet 2 I mvuvrox.

I (a, 2 m v 1 fi/fij I rron/var Dec. 2, 1958 E. oLsoN CARBURETOR THROTTLE MECHANISM 3 Sheets-Sheet 5 Filed Oct. 17, 1956 INVENTOR. M 67/2721 0/5022 ATTORNEY CARBURIETQR THRGTTLE MEfIl-IANISM Elmer OHson,;Roehester, N. 1., assignor to General Motors Corporation, Detroit, Mich a corporation of Delaware ApplientionOctoher 17, 1956, Serial No. 616,522

' 9 Claims. 123-493) The present invention relates to a throttle control mechanism particularly adapted for use with a carburetor governing system. The mechanism is particularly designed for use with a compound type carburetor in which it is necessary to control a plurality of sequentially operating throttles.

It has been found desirable, particularly with commercial vehicles such as trucks and busses, to provide means whereby the engine is protected against operation at excessive speeds which would otherwise be destructive thereof. One most satisfactory way to thus govern the speed of an engine is through the carburetion system whereby as excessive engine speeds are approached a speed responsive mechanism causes the carburetor to reduce the supply of combustible mixture flowing to the engine. This type of governing system has been satisfactorily utilized in the case of simple or non-compound type carburetors in which the throttle controllingv mechanism is required to operate a single throttle or where a plurality of throttles operate in phase, i. e., non-sequential operation.

In a carburetor of the type using sequentially operating throttles, i; e., where one throttle is adapted to open at a different rate than another, the actuating mechanism tendsto be somewhat complicated. The need for adding a governing function and its attendant mechanism to such a carburetor has presented an extremely dilficult situation both. from a functional as well as structural viewpoint.

The present invention has for its primary object the solution of governing a compound type carburetor through the use of a unique throttle controlling mechanism which will hereinafter be described in detail.

In the drawings:

Figure 1 is an elevational view of a carburetor embodying the subject invention;

Figure 2 is a partially sectioned view along line 22 of Figure 1;

Figure 3 is a view along line 3-3 of Figure 2; and

Figure 4 illustrates the carburetor governing system.

The present invention has been illustrated with a compound type carburetor of the four-barrel typeas generally shown in copending application Serial No. 264,136, now Patent No. 2,771,282, Olson et al., filed December 29, 1951. It is, of course, obvious that the invention is not limited to any particular type or configuration of a compound carburetor and may be adapted for use with any carburetor utilizing sequentially operating throttles.

The carburetor per se, will be described only insofar as it is necessary to provide sufiicient background for the present invention. The carburetor is generally indicated at and includes a plurality of induction passages 12, 14, 16 and 18 in each of which is respectively disposed a throttle 20, 22, 24 and 26 for controlling the flow of combustible mixture through the induction passages. Primary-throttles 20 and 22 are fixed on a rotatable shaft 28 and move in unison to control the primary induction passages 12 and 14. Similarly the secondary throttles 24 and 26 are fixed upon a rotatable shaft 30 to control the secondary induction passages 16 and 18.

Shaft 28 extends from the main body of the carburetor into a casing 32 formed on the carburetor body and adapted to be closed by a suitable cover 3 4. Fixed by a nut 36 on that portion of shaft 28 within casing 32 is a T-shaped lever 38. Similarly fixed on the secondary throttle shaft 36 is a bifurcated lever 40 having spaced arms 42 and 44. A lever is loosely mounted on the secondary throttle shaft 34 proximate fixedv lever 40 and includes a tang or lip 48 which projects between arms 42 and 44 of lever an. Alink 56 is articulated at one end to an arm 52 of lever 38 and is similarly articulated at the other end to an arm 54. of lever 46.

Levers 40 and 46 are resiliently coupled together through a helical spring 56 which is. coiled about shaft 30 intermediate the levers and terminates in end portions respectively fixed to arms 44 and 54 of levers 4i) and 46. Spring 56 biases lever 49 in a counterclockwise or closing direction. The space between arms 42 and 44 as well as the loose mounting of lever 46 on shaft 3% provides for relative movement between these levers for a purpose to be subsequently discussed.

Arm 60 of lever 38 includes a stud member 62 projecting therefrom and to which is connected one end of a coiledspring-member 64-. The other end of spring 64 is fixed to a stud 66 mounted on the carburetor body. The stud 52 of lever 33 is radially spaced from the primary throttle shaft 28 so that the spring 64 continuously exerts a throttle opening moment to the lever and shaft. In general, it will 'be seen that through lever 38; link 50 and levers 4t) and 46; the opening movement of the primary throttle may also have an opening effect on the secondary throttle, the details of which will now be discussed.

As shown in Figures 1 and 2 the various links and levers are in a position in which both the primary and secondaryv throttles are closed. In this position it will be seen that arm 54 of secondary throttle controlling lever 46 and link 50 are so relatedto. lever 38 that the initial opening movement of the primary throttle under the influence of spring 64 will cause arm 52 of lever 38 to pivot about the associated end of link 50 and also for the other end of the link to pivot about its connection with arm 54 of lever 46 without transmitting any rotary movement to lever 40. Thus, initially there. is no significant translatory movement of link 50- thereby permitting an opening movement to be imparted to the primary throttles 20 and 22 without affecting any opening of the secondary throttles. Once the arm 52 and the associated end of link 50 have moved sufficiently overcenter to have exhausted the pivotal movement referred to, continued throttle opening or counterclockwise movement of the primary throttle lever 38 will begin to impart a clockwise rotation to lever 4-6. Due to the space between the arms 42 and 44 of bifurcated lever 40 and the intermediate position .therebetween of tang 48:, a further incremental opening movement of the primary throttle will be permitted until such time as the tang engages with arm 44 of lever 40. The various members may be suitably proportioned to permit any desired degree of opening of the primary throttles before the actuation of the secondary throttles begins. In the device, as shown, the mechanism will permit the primary throttle to move to a position approximately 46 from the horizontal or approximately 50% open before actuation of the secondary throttle commences.

With the tang 48 engaging arm 44, further opening movement of the primary throttle will impart anopening movement to the secondary throttle which will continue to open during the remaining opening movement of the primary throttles but at a faster rate than the,

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primary throttles so that both primary and secondary throttles will reach full open position at substantially the same time.

While the spring means 64 provides the actual opening force for the throttles it is necessary to provide a manual control therefor in order that the operator may actually pre-select and control the degree of throttle opening and hence the speed of the engine. To this end, primary throttle shaft 23 also extends through the carburetor in the opposite direction from casing 32 and has a lever fixed to the end thereof. Lever 70 includes a projection 72 adapted to be engaged by a similar projection 74 on a lever 76 rotatably mounted in a cover 78 suitably fixed to the carburetor housing. Levers 7t) and 76 are coaxially related in such a way that the opening movement of primary throttle shaft 28 is inhibited by the angular position of the lever 76, the latter which is controlled through a suitable linkage mechanism, not shown, to the accelerator pedal. Thus with the accelerator pedal released indicating no need for power beyond idling, projection 74 on lever 76 engages projection 72 on lever 70 to maintain the throttles in a closed position against opening force of spring 64. As the operator gradually depresses the throttle, lever 76 will progressively rotate in a clockwise direction permitting the spring 64 to rotate shaft 28 an equal amount to open the throttles to the extent determined by the operator. For reasons to be subsequently discussed, it should be noted that projections 72 and '74 upon levers 70 and 76 are so related that the throttles may be closed without any regard for the position of lever 76 or the accelerator pedal.

In order to govern the carburetor and hence prevent the engine from operating at speeds which will be detrimental thereto, a governing mechanism is provided which includes a servomoto-r 8t} fixed to or integral with throttle linkage casing 32. The servomotor 80 includes a pair of casing members 82 and @4- having a flexible diaphragm 86 peripherally clamped therebetween in order to divide the casing into a pair of chambers 88 and 90. Suitably fixed to the diaphragm 86 is an actuating rod or link 92, the other end of which is articulated to arm 94 of primary throttle control lever 38. The con- 'nection between link 92 and lever 38 is diametrically opposite the connection between the aforesaid lever and spring 64. In this way the spring and diaphragm are adapted to provide opposite actuating forces on the primary throttle shaft 28 as will now be considered.

Servo chamber 88 is communicated through a pas- I sage 96 and a conduit 98 to the carburetor induction passage posteriorly of the throttles so as to convey manifold vacuum to said chamber which may act to move the diaphragm to the right, as shown in Figure 1, and close the throttles. Conduit 98 registers with a passage 100 formed in throttle body 101 and which latter passage terminates, as noted, in the induction passage 12 posteriorly of throttle 20. Orifices 102 and 104 are re spectively provided to determine generally the rate of servo actuation.

The influence of manifold vacuum on said diaphragm is, however, under the influence of a speed responsive mechanism indicated generally at and which mechanism permits atmospheric air to be bled into chamber 88 to destroy the vacuum therein until such time as the speed of the engine reaches a value sufiiciently high to shut off the atmospheric bleed.

The speed responsive mechanism 110 may be of the shown and described in Patent 2,664,867, Hartzell et al., filed February 14, 1951, and does not, per se, constitute a part of the present invention. The speed responsive mechanism is pertinent to the subject invention only in combination with the subject unique throttle controlling linkage arrangement. Insofar as the present invention is concerned it will sufiice to say of the speed responsive device 110 that it includes a shaft 112 driven at engine speed through a gear 114 connected in turn with a member 116 on the engine cam shaft. Radially mounted on the shaft 112 is a centrifugal valve mechanism 120 which is biased by spring 122 in a position in which spindle 124 uncovers port 126 admitting atmospheric air from an air cleaner conduit 128 to a passage 130 formed in shaft 112. Passage 130 in turn communicates at its other end with an annular chamber 132 in registry with a passage 134 connecting with conduit 136 communicating with the servo casing 82. Thus, as long as engine speed remains below a value which will permit safe operation of the engine, valve 120 continues to bleed atmospheric air to the servo chamber 88 precluding manifold vacuum from having any effect on the throttle actuating mechanism. When the engine exceeds a given value, the magnitude of which may be controlled by adjusting the rate of spring 122 through a nut 138 threaded on the valve spindle, centrifugal weight 140 closes port 126 shutting off the atmospheric bleed and enabling manifold vacuum to move diaphragm 86 to the right and thereby move primary throttle lever 38 in a clockwise or closing direction.

In so moving the primary throttle lever 38, link 50 and lever 46 are moved until tang 48 engages arms 42 of lever 40 imparting a counterclockwise or closing movement to the secondary throttles 24 and 26. Thus no matter how far the accelerator pedal is depressed the governing mechanism will insure that the maximum safe speed at which the engine can be run .will not be ex ceeded. It is to be recalled at this juncture that projections 72 and 74 on levers 70 and 76 coact to provide what is in effect a one-Way clutch between the accelerator pedal or manual control and the throttles whereby the accelerator determines the extent to which the throttles may be opened but the closing of which throttles may be over-controlled by the governing mechanism as described.

It is to be understood that structural modifications may be made in the throttle controlling mechanism described without departing from the scope of the invention.

I claim:

1. A compound carburetor comprising primary and secondary induction passages, throttles for respectively controlling flow through said passages, each throttle being fixed upon a rotatable shaft, first and second levers respectively fixed to the primary and secondary throttle shafts, a third lever rotatably supported upon the secondary throttle shaft, 2. link articulated between said first and third levers, means continuously urging said primary throttle toward open position, a lost motion connection between said second and third levers permitting a fixed amount of opening movement of said primary throttle before the secondary throttle begins to open, manually controlled means opposing the opening movement of the primary throttle, and a control device responsive to an engine operating condition for moving said first lever to .close said throttles against the opening force of said resilient means.

2. A compound carburetor comprising primary and secondary induction passages, throttles respectively controlling fiow through said passages, each throttle being fixed upon a rotatable shaft, first and second levers respectively fixed to the primary and secondary throttle shafts, a third lever rotatably supported upon the secondary throttle shaft, a link articulated between said first and second levers, means continuously urging said primary throttle toward open position, said second lever being bifurcated to provide a pair of spaced arms, said third lever including a tang portion extending between said arms and adapted to move relatively thereto, a resilient member connecting said second and third levers, said link, second and third levers being constructed to permit initial opening of said primary throttle before the secondary throttle begins to open, manually controlled means opposing the opening movement of the primary throttle, and a control device responsive to an engine operating condition for moving said first lever to close said throttles against the opening force of said resilient means.

3. A compound carburetor comprising primary and secondary induction passages, throttles for respectively controlling flow through said passages, each throttle being fixed upon a rotatable shaft, first and second levers respectively fixed to the primary and secondary throttle shafts, a third lever rotatably supported upon the secondary throttle shaft, a link articulated between said first and third levers, means connected to said first lever for continuously urging said primary throttle toward open position, a lost motion connection between said second and third levers permitting a fixed amount of opening movement of said primary throttle before the secondary throttle begins to open, manually controlled means opposing the opening movement of the primary throttle, and a control device articulated to said first lever and responsive to an engine operating condition for moving said first lever to close said throttles against the opening force of said resilient means.

4. A compound carburetor comprising primary and secondary induction passages, throttles for respectively controlling flow through said passages, each throttle being fixed upon a rotatable shaft, first and second levers respectively fixed to the primary and secondary throttle shafts, a third lever rotatably supported upon the secondary throttle shaft, a link articulated between said first and third levers, means connected to said first lever for continuously urging said primary throttle toward open position, a lost motion connection between said second and third levers permitting a fixed amount of opening movement of said primary throttle before the secondary throttle begins to open, manually controlled means opposing the opening movement of the primary throttle, and a control device articulated to said first lever on the opposite side of the primary shaft axis and responsive to an engine operating condition for moving said first lever to close said throttles against the opening force of said throttle opening means, said link being articulated to the first lever intermediate the connections of said primary throttle opening means and the control device.

5. A compound carburetor comprising primary and secondary induction passages, throttles for respectively controlling flow through said passages, each throttle being fixed upon a rotatable shaft, first and second levers respectively fixed to the primary and secondary throttle shafts, a third lever rotatably supported upon the secondary throttle shaft, a link articulated between said first and third levers, means continuously urging said primary throttle toward open position, a lost motion connection between said second and third levers permitting a fixed amount of opening movement of said primary throttle before the secondary throttle begins to open, a manually controlled lever rotatably mounted on said carburetor proximate said primary throttle shaft, said manually controlled lever being rotatable relative to the primary throttle shaft and adapted to engage the latter to limit the opening movement thereof, and a control device responsive to an engine operating condition for moving said first lever to close said throttles against the opening force of said resilient means.

6. A compound carburetor as defined in claim 5 in which said manually controlled lever is coaxially aligned with said primary throttle shaft and disposed on the opposite side of said carburetor from said first lever.

7. A compound carburetor comprising primary and secondary induction passages, throttles for respectively controlling flow through said passages, each throttle being fixed upon a rotatable shaft, first and second levers respectively fixed to the primary and secondary throttle shafts, a third lever rotatably supported upon the secondary throttle shaft, a link articulated between said first and third levers, means continuously urging said primary throttle toward open position, a lost motion connection between said second and third levers permitting a fixed amount of opening movement of said primary throttle before the secondary throttle begins to open, a fourth lever fixed to said primary throttle shaft and having a projection extending therefrom, a manually controlled lever rotatably mounted on said carburetor proximate said primary throttle shaft and having a projection disposed proximate the fourth lever projection, said manually controlled lever being rotatable relative to the primary throttle shaft whereby the manual lever projection is engaged by the fourth lever projection to limit the opening movement of said latter lever, and a control device responsive to an engine operating condition for moving said first lever to close said throttles against the opening force of said resilient means.

8. A compound carburetor comprising primary and secondary induction passages, throttles respectively controlling flow through said passages, each throttle being fixed upon a rotatable shaft, first and second levers respectively fixed to the primary and secondary throttle shafts, a third lever rotatably supported upon the secondary throttle shaft, a link articulated between said first and second levers, means continuously urging said primary throttle toward open position, said second lever being bifurcated to provide a pair of spaced arms, said third lever including a tang portion extending between said arms and adapted to move relatively thereto, a resilient member connecting said second and third levers, said link, second and third levers being constructed to permit initial opening of said primary throttle before the secondary throttle begins to open, manually controlled means opposing the opening movement of the primary throttle, a servomotor having a pressure responsive member, means connecting said member and said one throttle, a passage communicating manifold vacuum to said pressure responsive member to actuate said member and move said throttles toward closed position, a valve normally bleeding said passage to atmosphere, and engine speed responsive means adapted to close said atmospheric bleed.

9. A compound carburetor comprising primary and secondary induction passages, throttles for respectively controlling flow through said passages, each throttle being fixed upon a rotatable shaft, first and second levers respectively fixed to the primary and secondary throttle shafts, a third lever rotatably supported upon the secondary throttle shaft, a link articulated between said first and third levers, means connected to said first lever for continuously urging said primary throttle toward open position, a lost motion connection between said second and third levers permitting a fixed amount of opening movement of said primary throttle before the secondary throttle begins to open, manually controlled means opposing the opening movement of the primary throttle, a servomotor having a pressure responsive member articulated to said first lever on the opposite side of said primary shaft axis relative to said throttle opening means, a passage communicating manifold vacuum to said pressure responsive member to actuate said member and move said throttles toward closed position against the first of said throttle opening means, a valve normally bleeding said passage to atmosphere, and engine speed responsive means adapted to close said atmospheric bleed, said link being articulated to the first lever intermediate the connections of said primary throttle opening means and the pressure responsive member.

References Cited in the file of this patent UNITED STATES PATENTS 2,393,556 Olson et al. Jan. 22, 1946 2,399,080 Udale Apr. 23, 1946 2,415,510 Mallory Feb. 11, 1947 2,749,100 Carlson June 5, 1956 2,771,282 Olson et al. Nov. 20, 1956