US3852379A

US3852379A - Carburetor

Info

Publication number: US3852379A
Application number: US00383784A
Authority: US
Inventors: T Shishido; M Atsumi
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 1973-07-30
Filing date: 1973-07-30
Publication date: 1974-12-03
Anticipated expiration: 1991-12-03
Also published as: FR2239597B1; ES421490A1; BE808696A; JPS5063338A; CH589793A5; JPS5390529A; JPS5326618B2; JPS5326620B2; NL162718B; AR213062A1; CA983799A; AU6224973A; JPS5035539A; BR7402255A; JPS5063341A; JPS5063340A; SE7316968L; FR2239597A1; JPS5326619B2; DD113794A5

Abstract

A carburetor assembly has primary and secondary venturi passages to supply a lean mixture to main combustion chambers of an engine, and has an auxiliary venturi passage to supply a rich mixture to auxiliary combustion chambers of the engine. A throttle valve in each passage is provided with a shaft, and the shaft for the primary throttle valve projects through a hollow hub on the carburetor body. Several members and springs are mounted on the hub and serve to control turning movement of all throttle shafts during various operating conditions of the engine. A link is pivotally connected at one end to an arm which turns with the primary throttle valve and is pivotally connected at the other end to an arm which turns with the auxiliary throttle valve. An angular adjustment is provided between the auxiliary throttle valve and its respective arm. The geometric relationships of the link and arms are such as to provide the desired coordinated movement between the throttle valves.

Description

Dec.

3,570,821 3 1971 Walker............... HIM/23A CARBURETOR [75] Inventors: Toshimasa Shishido, Tokyo; Minoru n o y .L d n Sou k1 11m M ..L mm H r u .m[ in H8 i 5 e mm mm. f. PA n a. wnm a f 0M 3 m a 0WD- W "5K a eek a i a mMh nk $.03 AHK me e n .w S S A U 7 ABSTRACT July 30, 1973 [22] Filed:

A carburetor assembly has primary and secondary venturi passages to supply a lean mixture to main Appl. No.:

combustion chambers of an engine, and has an auxiliary venturi passage to supply a rich mixture to auxiliary combustion chambers of the engine. A throttle valve in each passage is provided. with a shaft, and the shaft for the primary throttle valve projects through a hollow hub on the carburetor body. Several members and springs are mounted on the hub and serve to con yGIA MG m m r m n2 a m y W D 2G S m W2 6m B7. n an 5H m mm m m r 5 .w U hF i i] 2 18 5 55 i [rt [56] References Ci d trol turning movement of all throttle shafts during various operating conditions of the en gine. A link is piv otally connected at one end to an arm which turns with the primary throttle valve and is pivot-ally coir nected at the other end to an arm which turns with the auxiliary throttle valve. An angullar adjustment is provided between the auxiliary throttle valve and its respective arm. The geometric relationships of the link 7 WAAA 333 222 3///3 /l 2 666 222. S M." T H mm N W mm E m..mm M mmmmm P I I H Wmm Mm r .r T we m m Am d nfla T acf SMWCRB D B82792 T35556 l99999 N U 0 632. 20052 1 984 209 2 22223 Edclbrock, Jr. l23/l27 and arms are such as to provide the desired coordinated movement between the throttle valves.

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Bartholomew................1... 261/23 A 23 Claims, 15 Drawing Figures PATENTEL E55 974 SIEEI 2 BF 5 PATENHQL BEE 31974 MEN 5 0f 5 I] CARBURETOR This invention relates to internal combustion sparkignition piston engines in which each cylinder is provided with a main combustion chamber and an auxiliary combustion chamber connected by a torch nozzle. An engine of this type is disclosed in the copending application of Date et a1. Ser. No. 353,786 filed Apr. 23, 1973 and entitled Reduction of N HC, and CO in the Exhaust Gases of Internal Combustion Engines.

More specifically, this invention relates to a carburetor assembly for supplying a lean mixture to the main combustion chambers and a rich mixture to the auxiliary combustion chambers. It is important that the airfuel ratios of the lean mixture and the rich mixture be maintained within close limits for all operating conditions of the engine, in order to avoid the production of unwanted pollutants in the exhaust gases of the engine. Thus, it is important to minimize production of pollutants during cranking, fast idling, slow idling, accelera tion, gear shifting, highway operation, slow deceleration, and rapid deceleration.

In accordance with this invention, the shaft for one of the throttle valves, preferably the primary throttle valve, projects through a stationary hollow hub formed integrally on the carburetor body. An actuator member is mounted to turn on the hub against the action of a spring, and the throttle cable is connected to the actuator member. A connector member fixed to the projecting end of the shaft connects the actuator member to the shaft. In this way, the tension in the throttle cable is resisted by the hollow stationary hub, and the tension does not result in bending of the throttle shaft. Other members affectingor modifying the turning movement of the throttle shaft are also mounted on the hollow stationary hub, and the lateral forces which they produce are also absorbed by the hub, and not by the throttle shaft. These features help to insure smooth opening and closing of the throttle valve.

Also, a novel controlling of connection is established between the primary throttle valve connecting the lean mixture and the auxiliary throttle valve controlling the rich mixture. This connection is accomplished without the use of cams, and very accurately regulates the position of the auxiliary throttle valve for each angular position of the primary throttle valve. This connection employs a link pivotally connected to a forward extending arm on one throttle shaft and pivotally connected to a rearward extending arm on the other throttle shaft,

together with an adjustment device for varying the angular position of one of the arms with respect to its re spective throttle shaft. In this way the linkage and adjustment device helps to insure that the proper amount of rich air-fuel mixture is supplied to the auxiliary combustion chambers of the engine, in relation to the amount of lean air-fuel mixture supplied to the main combustion chambers of the engine, under any oeprating condition of the engine. Also, a novel form of mechanism is employed for causing opening of the secondary throttle valve after the primary throttle valve has openeda predetermined amount, together with positive means for closing the secondary throttle valve as the primary throttle valve moves toward closed position. Vacuum-operated means are employed for positioning certain of the throttle valves during certain of the operating conditions of the engine. Additional means are provided for preventing too rapid closure of certain throttle valves and for insuring rapid closing of the throttle valves when the electrical ignition system is de-energized.

Other and more detailed objects and advantages will appear hereinafter. In the drawings:

FIG. 1 is a side elevation partly broken away showing a preferred embodiment of our invention.

FIG. 2 is a sectional elevation taken substantially on the lines 2-2 as shown in FIG. 1.

FIG. 3 is a bottom plan view showing a portion of the apparatus.

FIG. 4 is a top plan view of the same portion of the apparatus.

FIG. 5 is a side elevation,,certain parts being omitted for clarity of illustration and showing the primary throttle valve in closed position.

FIG. 6 is a view similar to FIG. 5 showing the primary throttle valve in open position.

FIG. 7, 8 and 9 are side elevations showing details of the cam and follower connection between the primary throttle valve and the secondary throttle valve.

FIG. 10 is a plan view showing a modification.

FIG. 11 is a side elevation of the device shown in FIG. 10.

FIG. 12 is a plan view of a portion of FIG. 10, certain parts being omitted.

FIG. 13 is a sectional detail taken substantially on lines 13l3 as shown on FIG. 10,

FIG. 14 is a side elevation showing a second modification.

FIG. 15 is a sectional detail taken substantially on the line l5l5 as shown in FIG. 14.

Referring to the drawings, a carburetor assembly generally designated 10includes a metal body 11 having walls defining a primary passage12, a secondary passage 13 and an auxiliary passage 14. These passages are parallel and each is provided with a

venturi throat

15, 16 and 17, respectively Fuel jets fed from float chambers within the body 11 produce a lean mixture in the

passages

12 and 13 to supply the main combustion chambers of the engine and produce a rich mixture in the passage 14 to supply the auxiliary combustion chambers of the engine Each of the

passages

12, 13 and 14 is provided with a throttle valve carried on a shaft which turns relative to the carburetor body 11. Thus, the primary throttle valve 18 is fixed on the shaft 19, secondary throttle valve 20 is fixedon the shaft 21, and auxiliary throttle valve 22 is fixed on the shaft 23. The

shafts

19, 21 and 23 are parallel.

As best shown in FIG. 2, a tubular part is cast into a wall of the carburetor body 11 and projects outward therefrom to form a hollow hub 24 encircling a portion of the throttle shaft 19. An actuator member'generally designated 25 is mounted to turn on the stationary hub 24, and this member 25 is constructed of two

metal stampings

26 and 27 fixed together by a pin 28 to turn as a single integral unitQThis unitary member 25 is acted on by a torsion spring 29 which encircles the hub 24 whichhasone end engaging the stop pin 30 and the other end 31 engaging the unitary member 25. The torsion spring 29 thus acts on the unitary member 25 to turn it in .a clockwisedirection as viewed in FIG. 1, opposing opening movement of the primary throttle valve 18.

The part 26 of theunitary member 25 includes an axially extending fin 33 which has a portion thereof received within slot 34 on the Connecting member 35.

The connecting member 35 is fixed to a projecting end portion of the shaft 19 by means of the nut 36. From this description it will be understood that the unitary member is mounted on the stationary hollow hub 24 but is connected to turn with the throttle shaft 19.

The part 27 of the unitary member 25 carries an integral socket 37 which receives a terminal fitting 38 at the end of'the throttle cable 39. This cable 39 passes through an enclosing tube 40 fixed to the stationary bracket 41 by means of lock nuts 42. Tension applied to the throttle cable 39 acts on the unitary member 25 to turn it in a clockwise direction as viewed in FIG. 1, against the action of the torsion spring 29. This turning movement of the member 25 causes the connecting member 35 to turn the throttle shaft 19 in a direction to open the primary throttle valve 18 in the passage 12. The closed position of the throttle valve 18 is determined by the setting of the adjusting screw 43 which engages the stop finger 44 provided on the part 27. Opening movement of the throttle valve 18 is limited by contact of the stop finger 45 with the stationary stop pin 30.

The linear force applied by the throttle cable 39 to the socket 37 does not place a bending loadon the throttle shaft 19 because the actuator member 25 is mounted on the stationary hub 24 and not on the shaft 19. The torque on the member 25 is transmitted to .the throttle shaft 19 through the connecting member 35.

Two other members are mounted to turn on the hollow hub 24. One of these, the throttle positioner 47, has an arm 48 pivotally connected to an actuator rod 49 extending from the vacuum-operated diaphragm assembly 50. Another arm on the throttle positioner'47 has a rounded nose portion 51 engaging a side face of the fin 33. The slot 52 is provided for initial factory adjustment ofthe rounded nose 51 with respect to the fin 33, by inserting a deforming tool into the slot. The other member, mounted to turn on the hollow hub 24, is identified by the numeral 53, and this member has a first arm 54 pivotally connected at 55 to the actuator rod 56 extending .from the diaphragm assembly 57. A rounded nose portion 58 on the arm 54 contacts the shoulder 59 on the part 27 of the unitary member 25.

, The slot provides a means for factory adjustment of the position of the rounded nose 58.

The part 27 of the unitary member 25 has an external cam surface 62 which cooperates with the follower roller 63 on the member 64. This member turns with the shaft 21 for the secondary throttle valve 20. The shaft 21 projects through the hollow stationary hub 65 and its projecting end is fixed to the member 64. Another member 66' is mounted to turn on the stationary hub 65 and is provided with'a radial projection 67 which is engaged by one end 68 of a torsion spring 69. The other end 70 of the torsion spring engages a stationary projection 71 on the carburetor body 11. From this description it will be understood that the torsion spring 69 acts to turn the member 66 in a clockwise direction as viewed in FIG. 1. The projection 67 on the member 66 applies a force to the finger 72 of the member 64 in a direction opposing opening movement of the secondary throttle valve 20. A roller 72a mounted on the unitary member 25 engages the cam surface 73 on a member 66 after the primary throttle shaft 19 has passed through a predetermined arc of travel in an opening direction. Further turning movement of the unitary member 25 in an opening direction causes the roller 72a to move the member 66 in a counterclockwise direction against the action of the torsion spring 69.

Prior to engagement of the roller 72a with the cam surface 73, the cam surface 62 is moved with respect to the roller 63 to a position wherein the member 64 may turn in a counterclockwise direction. Turning movement of the secondary throttleshaft 21 is accomplished by means of the vacuum-operated diaphragm assembly 75 acting through rod 76 and pivotal connection 77 with-the member 64.

Means are provided for coordinating the movement of the primary throttle valve 18 and the auxiliary throttle valve 22. It is essential that these two throttle valves be accurately controlled during-all operating conditions of the engine, in order to minimize unwanted pollutants in the exhaust gases of the engine. A link 78 is pivotally connected at 79 to a forward extending arm 80 carried on the actuator member 25. The link 78 is pivotally connected at 81 to the rearward extending arm 82 on the member 83 which turns about the axis of the throttle shaft 23. Another member 84 which is fixed to the throttle shaft 23 is adjustable connected to the member 83 by means of the adjusting screw 85. The adjusting screw controls the relative angular positions of the

members

83 and 84, and in this way controls the relative positions of the pivot 81 with respect to the auxiliary throttle valve 22. A tension spring 86 extends between the pivots 79 and 81 to take up any looseness.

The

throttle valves

18 and 22 are shown in closed position in FIG. 5 and in open position in FIG. 6. In order to obtain the desired angular movement of the auxiliary throttle valve 22, with respect to the primary throttle valve 18, the effective length a of the short arm 80 should be about 3/4 of the effective length [2 of the long arm 82, as shown in FIG. 6. Also, the following relationship should exist:

(a c)/z1= 0.9 l.2

where:

a effective length of the short arm 80 c effective length of the link 78 d distance between centerlines of throttle shafts l9 and 23.

FIGS. 7, 8 and 9 are diagrams showing how the primary throttle valve 18 moves with respect to the secon dary throttle valve 20. In FIG. 7 both

throttle valves

18 and 20 are closed. When the terminal fitting 38 of the throttle cable 39 acts on the socket 37 to open the primary throttle valve 18 about 40, as shown in FIG. 8, the secondary throttle valve 20 remains closed because the cam roller 72a hasjust reached the cam surface 73 on the member 66. Continuing opening movement of the primarythrottle 18 causes the roller 72a on the cam surface 73 to turn the member 66 in a counterclockwise direction against the action of the torsion spring 69. This moves the projection 67 away from the member 64 so that the diaphragm assembly 75 may turn the throttle shaft 21 in a counterclockwise direction to open the secondary throttle valve 20. In FIG. 9 both

throttle valves

18 and 20 are shown in open position.

As shown in FIG. 2, a crank arm 87 may be fixed to a projecting end of the shaft 19 for connection to a conventional accelerator pump, not shown.

In operation, initial cranking of the engine may require use of the choke device 88. During this initial cranking the primary throttle valve 18 and the auxiliary throttle valve 22 are in fast idle" position and the sec ondary throttle valve 20 is closed. When the engine starts to turn under its own power and cranking is discontinued, the accelerator pedal (not shown) is operated to move the throttle control cable 39 to turn the actuator member 25 in a clockwise direction as viewed in FIG. 1. This causes opening movement of the primary throttle valve 18 and opening movement of the auxiliary throttle valve 22.

Initial movement of the actuator member 25 is resisted by the torsion spring 29, and after the member 25 turns a few degrees the rod 56 bottoms out? within the device 57, preventing further turning movement of V the member 54. Further turning movement by the actuator member 25 is resisted by both torsion springs 29 and 32.

When the primary throttle valve opens about 40 degrees, the cam surface 62 has moved to permit the roller 63 and member 64 to turn about the axis of the secondary throttle valve shaft 21. The heavy flow of air through the primary passage 12 produces a marked pressure drop in the venturi throat 15. A passage (not shown) connects this low pressure zone in the venturi to the vacuum-operated diaphragm assembly 75. Continued opening movement of the primary throttle valve 18 by means of the throttle control cable 39 causes an increase in speed of the engine with consequent increase in volume of air drawn through the venturi throat 15. This in turn produces a greater pressure depression at the venturi throat and causes the vacuuni-operated diaphragm assembly 75 to tension the rod 76 and thereby open the secondary throttle valve 20. This supplies additional quantities of lean mixture to the main combustion chambers of-the engine. At the same time the

linkage

78, 80 and 82 further increases the opening of the auxiliary throttle valve 22 to provide an increase in the rate of delivery of the rich mixture to the auxiliary combustion chambers of the engine.

A control valve (not shown) connects the vacuumoperated diaphragm assembly 50 to manifold suction pressure only when the suction pressure reaches a predetermined magnitude, for example 530 mm of mer tle valve 18 is moving toward closed position, because the vacuum intensity in the device 75 is not reduced quickly enough to respond to the change insuction pressure at the primary venturi throat 15. This difficulty is overcome by the action of the cam surface 62 and follower roller 63, which action forces closing of the secondary throttle valve asthe primary throttle valve 18 closes. Continual gradual deceleration causes further closing movement of the primary and secondary throttle valves, and the closing motion of the auxiliary throttle valve 22'is coordinated with the closing motion of the primary throttle valve 18.

If the operator of the vehicle rapidly lifts his foot away from the accelerator pedal, rapid deceleration of the engine occurs because the primary throttle valve 18 and the auxiliary throttle valve 22 move toward idling position while the secondary throttle valve 20 moves toward closed position. The positioner assembly 50 acts to hold the throttle valve open to a greater degree than its idle position during deceleration above a predetermined speed of the vehicle, to minimize formation of unwanted emissions in the engine exhaust. The diaphragm assembly 57 first acts as a dash pot to limit too rapid closing of the primary and auxiliary throttle valves, which might interfere with proper operation of the engine. It is desirable to reduce the closing rate of the primary throttle valve 18 as it approaches closed position, when the vehicle operator removes his foot from the accelerator pedal for shifting gears or for de celeration. This is necessary to overcome the function of the positioner assembly 50 which does not respond rapidly when the throttle valve 18 is rapidly approaching toward closed position. Below about 12 miles per hour, a speed sensitive switch (not shown) interrupts the supply of vacuum pressure to the assembly 50, to allow closing of the primary throttle valve 18 to idle position. The device 57 may also serve as a run-on preventer by venting its internal chamber to atmosphere when the electrical ignition circuit is de-energized.

In the modified form of the invention shown in FIGS. 10-13, the carburetor assembly is employed for furnishing a lean mixture to each of the main combus tion chambers of the engine, and a second carburetor assembly 101 is provided for furnishing a rich mixture to the auxiliary combustion chambers of the engine. The first carburetor assembly 100 is conventional in form and employs a throttle actuator bar 102 for operating the throttle valves of the conventional carburetor assembly 100. The throttle bar 102 is pivotally connected at 103 to the crank member 104 secured to the intermediate shaft 105. A tension spring 106 connects the crank member 104 to turn the shaft in a counterclockwise direction, as viewed in FIG. 10. The auxiliary throttle valve 107 is fixed on the throttle shaft 108 mounted to turn on the body 109 of the carburetor 101. A cam member 110 is fixed to a disk 111 secured to the shaft 105 and this cam 110 has a cam surface 112 engaged by a follower roller 113 on crank arm'1l4. The crank 115 connected to the throttle shaft 108 is adjustably connected to the crank. arm 114 by means of the adjusting screw 116. From this description it will be understood that turning movement of the intermediate shaft 105 causes turning movement of the throttle valve 107 through the cam 110, follower roller 113, ad justing screw 116 and member 115.

The intermediate shaft 105 is supported in a bearing 118 fixed on the stationary bracket 119. The shaft 105 is also supported within the. stationary hollow hub 120 fixed to the stationary bracket 121. An actuator mem ber 122 is mounted to turn on the hub 120 and is provided with a socket 123 for reception of the end fitting 124 of the throttle cable 125. A tension spring 126 is connected to the actuator member 122 to resist clockwise motion, as viewed in FIG. 11. A finger 132 on the member 104 projects over the actuator member 122 so that turning movement of the actuator member 122 under force applied by the throttle cable 125 and against the action spring 126 serves to rotate the member 104 to turn the intermediate shaft 105.

The diaphragm assembly 127 acts through rod 128 and pivotal connection 129 to member 130 which is mounted to turn on the hollow stationary hub 120. A finger 131 fixed to the disk 111 overlies a portion of the member 130, so that tensioning of the rod 128 serves to turn the shaft 105 in a clockwise direction, as viewed in FIG. 10. This device may be referred to as a dash potv to prevent too rapid closing of the throttle valves.

The vacuum-operated diaphragm assembly 133 acts through rod 134 and pivotal connection 135 to turn the member, 136 which is mounted to turn on the stationary bearing 118. Another member 137 fixed to a projecting end of the shaft 105 has a finger 138 overlying a portion of the member 136, so that tensioning of the rod 134 serves toturn the shaft 105. This device may be referred to as a throttle positioner.

It will be observed that the shaft 105 which is connected to turn the auxiliary throttle valve 108 is actuated from the throttle cable 125 through a member mounted to turn on the stationary hub 120, and that the shaft 105 projects through the hub 120 so that the bending load caused by cable tension is taken by the stationary hub 120 and not by the shaft 105. Also, it

will be observed that turning movement of the throttle 1 valve shaft 108 is affected by the action of the diaphragm assembly 127, and vacuum-operated device 133, in addition to the action of the throttle cable 125.

In the further modified form of the invention shown in FIGS. 14 and 15, the conventional carburetor 100 is employed as before and its throttle valves are operated by the throttle actuator bar 102. However, there is no intermediate shaft corresponding to shaft 105, and instead the auxiliary throttle valve shaft 140 is directly connected through member 141 to

members

142 and 143 which are mounted to turn on the stationary hollow hub 144. This hub 144 is integrally formed with the body 145 of the auxiliary carburetor assembly 146. The auxiliary throttle valve 147 is mounted in the passage 148 and serves to control the supply of rich mixture to the auxiliary combustion chambers of the engine.

The throttle cable 150 has its end fitting 151 received in the socket 152 mounted on the member 142. Tensioning of the throttle cable 150 serves to turn the member 142 in a clockwise direction, as viewed in FIG.

mit the throttle valve 147 to open beyond a certain po-' sition without interferencefrom the relatively

short stroke rods

158 and 159.

The operation of the modified forms of the invention shown in FIGS. 10-13 and 14-15 will be apparent from the foregoing description of the preferred embodiment.

Having fully described our invention, it is to be understood that we are not to be limited to the details set forth but that our invention is of the full scope of the appended claims.

We claim:

l. A carburetor assembly for use with an internal combustion engine having at least one main combustion chamber and an auxiliary combustion chamber connected thereto by a torch nozzle, said carburetor assembly having, in combination: a primary passage adapted to supply a lean mixture to the main combustion chamber of the engine, an auxiliary passage adapted to supply a rich mixture to the auxiliary com bustion chamber of the engine, each of the passages having a throttle valve therein carried on a shaft, means mounting said shafts for turning movement, said means including a hollow stationary hub encircling a portion of one of said shafts, a member mounted to turn on the hub, means for applying a linear force to said member to cause it to turn in one direction, resilient means connected to turn the member in the other direction, means on an end of the shaft projecting from the hub connecting said member to turn said shaft, and means for coordinating turning movements of said shafts.

2. The combination set forth in claim 1 in which said resilient means comprises a torsion spring encircling the hub.

3. The combination set forth in claim 1 in which the primary and auxiliary passages are both provided in a carburetor body, and wherein the hollow stationary hub projects from the body.

4. The combination set forth in claim 1 in which the primary passage is formed in one body and the auxiliary passage is formed in another body spaced therefrom.

5. The combination set forth in claim 1 in which the latter said means includes adjusting means for changing the angular position of the auxiliary throttle valve with respect to the primary throttle valve.

6. The combination set forth in claim 1 in which the latter said means includes an arm connected to turn with each of said shafts, respectively, a link pivotally connected to each of said arms, and means for adjusting the angular position of one of the arms with respect to its respective shaft.

7. A carburetor assembly for use with an internal combustion engine having at least one main combustion chamber and an auxiliary combustion chamber connected thereto by a torch nozzle, said carburetor assembly having, in combination: a body having a primary passage, a secondary passage, and a auxiliary passage therein, the primary passage and the secondary passage being adapted to supply a lean mixture to the main combustion chamber of the engine, the auxiliary passage being adapted to supply a rich mixture to the auxiliary combustion chamber of the engine, each of the passages havinga throttle valve therein and carried on a shaft, means mounting said shafts to turn on the body, said means including a hollow stationary hub projecting from the body and encircling a portion of one of said shafts, a member mounted to turn on the hub, means for applying a linear force to said member to cause it to turn in one direction, resilient means connected to turn the member in the other direction, and means on an end of the shaft projecting from the hub connecting said member to turn saidshaft, and means for coordinating turning movements of said shafts.

8. The combination set forth in claim 7 in which said resilient means comprises a torsion spring encircling said hub.

9. The combination set forth in claim 7 in which vacuum-operated means are provided for turning the secondary throttle shaft, and cam and follower means acting to permit movement of the secondary throttle sh'aft by said vacuum-operated means.

10. A carburetor assembly for use with an internal combustion engine having at least one main combustion chamber and an auxiliary combustion chamber connected thereto by a torch nozzle, said carburetor assembly having, in combination: a primary passage and a secondary passage adapted to deliver a lean mixture to the main combustion chamber of the engine, an auxiliary passage adapted to deliver a rich mixture to the auxiliary combustion chamber of the engine, each of said passages having a' throttle valve therein mounted on a throttle shaft, means mounting said throttle shafts for turning movement about parallel axes, a forward extending arm connected to turn with the primary throttle shaft, a rearward extending arm connected to turn with the auxiliary throttle shaft, a link pivotally connected to each of said arms to cause the primary throttle valve and the auxiliary throttle valve to turn in opposite directions, and means including a cam and follower for causing turning movement of the secondary throttle valve after the main throttle valve has turned through a predetermined arc of travel.

ll. The combination set forth in claim 10 in which angular adjustment means are interposed between the rearward extending arm and the auxiliary throttle shaft.

12. A carburetor assembly for use with an internal combustion engine having at least one main combustion chamber and an auxiliary combustion chamber connected thereto by a torch nozzle, said carburetor assembly having, in combination: a primary passage adapted to deliver a lean mixture of the main combustion chamber of the engine, an auxiliary passage adapted to deliver a rich mixture to the auxiliary combustion chamber of the engine, each of said passages having a throttle valve therein mounted on a throttle shaft, means mounting said throttle shafts for turning movement about parallel axes, a forward extending arm connected to turn with the primary throttle shaft, a rearward extending arm connected to turn with the auxiliary throttle shaft, the effective length of the forward arm being approximately three-fourth ofthat of the rearward arm, a link pivotally connected to each of said arms to cause the primary throttle valve and the auxiliary throttle valve to turn in opposite direction, the parts having the following geometric relationship:

(a c)/d =09 1.2

rearward extending arm with respect to the auxiliary throttle valve.

14. The combination set forth in claim 12 in which the primary throttle shaft extends through a stationary hollow hub, an actuator member mounted to turn on the hub and carrying said forward arm, and means connecting the actuator member to the primary throttle shaft.

15. A carburetor assembly for use with an internal combustion engine having at least one main combustion chamber and an auxiliary combustion chamber connected thereto by a torch nozzle, said carburetor assembly having, in combination: a primary passage and a secondary passage adapted to deliver a lean mixture of the main combustion chamber of the engine, an auxiliary passage adapted to deliver a rich mixture to the auxiliary combustion chamber of the engine, each of said passages having a throttle valve therein mounted on a throttle shaft, means mounting said throttle shafts for turning movement about parallel axes, means connecting the main throttle valve and the auxiliary throttle valve for coordinated turning movement, means for causing turning movement of the secondary throttle valve after the main throttle valve has turned through a'predetermined arc of travel, said means including vacuum operated means for turning the secondary throttle valve, a spring opposing the action of the vacuum operated means, and means including a cam and follower acting to limit the extent of turning movement of the secondary throttle shaft by said vacuum operated means.

16. A carburetor assembly for use with an internal combustion engine having at least one main combustion chamber and an auxiliary combustion chamber connected thereto by a torch nozzle, said carburetor assembly having, in combination: a primary passage adapted to deliver a lean mixture to the main combustion chamber of the engine, an auxiliary passage adapted to deliver a rich mixture to the auxiliary combustion chamber of the engine, each of said passages having a throttle valve therein mounted on a throttle shaft, means mounting said throttle shafts for turning movement about parallel axes, a hollow stationary hub, a member mounted to turn on the hub, means for ap plying a force to said member to cause it to turn in one direction, resilient means connected to turn the member in the other direction, means connecting said member to turn one of said shafts, and means for coordinating turning movements of said shafts.

17. The combination set forth in claim 16 in which said hollow hub member receives the shaft for the auxiliary throttle valve.

18. The combination set forth in claim 16 in which said hollow hub member receives an intermediate shaft positioned between said throttle shafts.

19. The combination set forth in claim 16 in which the latter said means includes adjusting means for changing the angular position of the auxiliary throttle valve with respect to the primary throttle valve,

20. A carburetor assembly for use with an internal combustion engine having at least one main combustion chamber and an auxiliary combustion chamber connected thereto by a torch nozzle, said carburetor assembly having, in combination: a primary passage and a secondary passage each adapted to deliver a lean mixture to the main combustion chamber of the engine, an auxiliary passage adapted to deliver a rich mixture to the auxiliary combustion chamber of the engine, each of said passages having a throttle valve therein mounted on a throttle shaft, means mounting said throttle shafts for turning movement about parallel axes, said means including two hollow stationary hubs, the first hub encircling a portion of the principal throttle shaft and the second hub encircling a portion of the secondary throttle shaft, a first member mounted to turn on the first huband having means for connection to a throttle actuator, means connecting said first member to the primary throttle shaft, a second member mounted to turn on the second hub and connected to the secondary throttle shaft, means for causing turning movement of the second member after said first member has turned through a predetermined arc of travel, and means for coordinating turning movement of the primary throttle shaft and the auxiliary throttle shaft.

21. The combination set forth in claim 20 in which the latter said means includes adjusting means for changing the angular position of the auxiliary throttle valve with respect to the primary throttle valve.

22. The combination set forth in claim 20 in which the means for causing turning movement of the second member includes a spring acting to turn the second member, a cam on the first member and a follower on adapted to supply a rich mixture to'the auxiliary combustion chamber of the engine, each of the passages having a throttle valve therein carried on a shaft, means mounting said shafts for turning movement, an actuator member mounted to turn about the axis of the primary throttle shaft, means connecting said actuator member to said primary throttle shaft, a first torsion spring resisting turning movement of said actuator member in a direction to open said primary throttle valve, a second member mounted to turn about said axis, a second torsion spring operatively interposed between said actuator member and said second member, a dash-pot device including a rod pivotally connected to said second member and acting to limit the rate of turning movement of said member in a direction corresponding to closing movement of said throttle valve, said rod having a limited stroke, means whereby said second member may turn the actuator member in the opposite direction until said rod reaches the limit of its stroke, whereby turning movement of the actuator member to open the primary throttle valve is first resisted only by the first said torsion spring until said rod reaches the limit of its stroke and whereby continued turning movement of said actuator in the same direction is resisted by both said torsion springs, and means for coordinating the movements of the primary throttle shaft and the auxiliary throttle shaft.

UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3,852,379

DATED December 3, 1974 lNV ENTOR(S) Toshimasa Shishido. et a1 It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In column 2, line 63, change "clockwise" to read counterclockwise-.

In column 3, line 45 "slot 10" should read slot 60----.

Signed and Sealed this Twenty-seventh Day Of July 1976 [SEAL] A ttes t:

RUTH C. MASON C. MARSHALL DANN Arresting Officer (mnmissiuner ufParems and Trademarks

Claims

1. A carburetor assembly for use with an internal combustion engine having at least one main combustion chamber and an auxiliary combustion chamber connected thereto by a torch nozzle, said carburetor assembly having, in combination: a primary passage adapted to supply a lean mixture to the main combustion chamber of the engine, an auxiliary passage adapted to supply a rich mixture to the auxiliary combustion chamber of the engine, each of the passages having a throttle valve therein carried on a shaft, means mounting said shafts for turning movement, said means including a hollow stationary hub encircling a portion of one of said shafts, a member mounted to turn on the hub, means for applying a linear force to said member to cause it to turn in one direction, resilient means connected to turn the member in the other direction, means on an end of the shaft projecting from the hub connecting said member to turn said shaft, and means for coordinating turning movements of said shafts.

7. A carburetor assembly for use with an internal combustion engine having at least one main combustion chamber and an auxiliary combustion chamber connected thereto by a torch nozzle, said carburetor assembly having, in combination: a body having a primary passaGe, a secondary passage, and a auxiliary passage therein, the primary passage and the secondary passage being adapted to supply a lean mixture to the main combustion chamber of the engine, the auxiliary passage being adapted to supply a rich mixture to the auxiliary combustion chamber of the engine, each of the passages having a throttle valve therein and carried on a shaft, means mounting said shafts to turn on the body, said means including a hollow stationary hub projecting from the body and encircling a portion of one of said shafts, a member mounted to turn on the hub, means for applying a linear force to said member to cause it to turn in one direction, resilient means connected to turn the member in the other direction, and means on an end of the shaft projecting from the hub connecting said member to turn said shaft, and means for coordinating turning movements of said shafts.

9. The combination set forth in claim 7 in which vacuum-operated means are provided for turning the secondary throttle shaft, and cam and follower means acting to permit movement of the secondary throttle shaft by said vacuum-operated means.

10. A carburetor assembly for use with an internal combustion engine having at least one main combustion chamber and an auxiliary combustion chamber connected thereto by a torch nozzle, said carburetor assembly having, in combination: a primary passage and a secondary passage adapted to deliver a lean mixture to the main combustion chamber of the engine, an auxiliary passage adapted to deliver a rich mixture to the auxiliary combustion chamber of the engine, each of said passages having a throttle valve therein mounted on a throttle shaft, means mounting said throttle shafts for turning movement about parallel axes, a forward extending arm connected to turn with the primary throttle shaft, a rearward extending arm connected to turn with the auxiliary throttle shaft, a link pivotally connected to each of said arms to cause the primary throttle valve and the auxiliary throttle valve to turn in opposite directions, and means including a cam and follower for causing turning movement of the secondary throttle valve after the main throttle valve has turned through a predetermined arc of travel.

11. The combination set forth in claim 10 in which angular adjustment means are interposed between the rearward extending arm and the auxiliary throttle shaft.

12. A carburetor assembly for use with an internal combustion engine having at least one main combustion chamber and an auxiliary combustion chamber connected thereto by a torch nozzle, said carburetor assembly having, in combination: a primary passage adapted to deliver a lean mixture of the main combustion chamber of the engine, an auxiliary passage adapted to deliver a rich mixture to the auxiliary combustion chamber of the engine, each of said passages having a throttle valve therein mounted on a throttle shaft, means mounting said throttle shafts for turning movement about parallel axes, a forward extending arm connected to turn with the primary throttle shaft, a rearward extending arm connected to turn with the auxiliary throttle shaft, the effective length of the forward arm being approximately three-fourth of that of the rearward arm, a link pivotally connected to each of said arms to cause the primary throttle valve and the auxiliary throttle valve to turn in opposite direction, the parts having the following geometric relationship: (a + c)/d 0.9 -1.2 where: a effective length of forward arm c effective length of the link d distance between centerlines of throttle shafts.

13. The combination set forth in claim 12 in which means are provided for adjusting the position of the rearward extending arm with respect to the auxiliary throttle valve.

15. A carburetor assembly for use with an internal combustion engine having at least one main combustion chamber and an auxiliary combustion chamber connected thereto by a torch nozzle, said carburetor assembly having, in combination: a primary passage and a secondary passage adapted to deliver a lean mixture of the main combustion chamber of the engine, an auxiliary passage adapted to deliver a rich mixture to the auxiliary combustion chamber of the engine, each of said passages having a throttle valve therein mounted on a throttle shaft, means mounting said throttle shafts for turning movement about parallel axes, means connecting the main throttle valve and the auxiliary throttle valve for coordinated turning movement, means for causing turning movement of the secondary throttle valve after the main throttle valve has turned through a predetermined arc of travel, said means including vacuum operated means for turning the secondary throttle valve, a spring opposing the action of the vacuum operated means, and means including a cam and follower acting to limit the extent of turning movement of the secondary throttle shaft by said vacuum operated means.

16. A carburetor assembly for use with an internal combustion engine having at least one main combustion chamber and an auxiliary combustion chamber connected thereto by a torch nozzle, said carburetor assembly having, in combination: a primary passage adapted to deliver a lean mixture to the main combustion chamber of the engine, an auxiliary passage adapted to deliver a rich mixture to the auxiliary combustion chamber of the engine, each of said passages having a throttle valve therein mounted on a throttle shaft, means mounting said throttle shafts for turning movement about parallel axes, a hollow stationary hub, a member mounted to turn on the hub, means for applying a force to said member to cause it to turn in one direction, resilient means connected to turn the member in the other direction, means connecting said member to turn one of said shafts, and means for coordinating turning movements of said shafts.

19. The combination set forth in claim 16 in which the latter said means includes adjusting means for changing the angular position of the auxiliary throttle valve with respect to the primary throttle valve.

20. A carburetor assembly for use with an internal combustion engine having at least one main combustion chamber and an auxiliary combustion chamber connected thereto by a torch nozzle, said carburetor assembly having, in combination: a primary passage and a secondary passage each adapted to deliver a lean mixture to the main combustion chamber of the engine, an auxiliary passage adapted to deliver a rich mixture to the auxiliary combustion chamber of the engine, each of said passages having a throttle valve therein mounted on a throttle shaft, means mounting said throttle shafts for turning movement about parallel axes, said means including two hollow stationary hubs, the first hub encircling a portion of the principal throttle shaft and the second hub encircling a portion of the secondary throttle shaft, a first member mounted to turn on the first hub and having means for connection to a throttle actuator, means connecting said first member to the primary throttle shaft, a second member mounted to turn on the second hub and connected to the secondary throttle shaft, means for causing turning movement of the second member after said first member has turned through a predetermined arc of travel, and Means for coordinating turning movement of the primary throttle shaft and the auxiliary throttle shaft.

22. The combination set forth in claim 20 in which the means for causing turning movement of the second member includes a spring acting to turn the second member, a cam on the first member and a follower on the second member for limiting motion of the second member under force applied by the spring.

23. A carburetor assembly for use with an internal combustion engine having at least one main combustion chamber and an auxiliary combustion chamber connected thereto by a torch nozzle, said carburetor assembly having, in combination: a primary passage adapted to supply a lean mixture to the main combustion chamber of the engine, an auxiliary passage adapted to supply a rich mixture to the auxiliary combustion chamber of the engine, each of the passages having a throttle valve therein carried on a shaft, means mounting said shafts for turning movement, an actuator member mounted to turn about the axis of the primary throttle shaft, means connecting said actuator member to said primary throttle shaft, a first torsion spring resisting turning movement of said actuator member in a direction to open said primary throttle valve, a second member mounted to turn about said axis, a second torsion spring operatively interposed between said actuator member and said second member, a dash-pot device including a rod pivotally connected to said second member and acting to limit the rate of turning movement of said member in a direction corresponding to closing movement of said throttle valve, said rod having a limited stroke, means whereby said second member may turn the actuator member in the opposite direction until said rod reaches the limit of its stroke, whereby turning movement of the actuator member to open the primary throttle valve is first resisted only by the first said torsion spring until said rod reaches the limit of its stroke and whereby continued turning movement of said actuator in the same direction is resisted by both said torsion springs, and means for coordinating the movements of the primary throttle shaft and the auxiliary throttle shaft.