US1847724A - Charge forming device - Google Patents

Description

March 1,1932. c. v. .MoRToN 1,847,724

CHARGE FORMING DEVICE Filed Jan. 2l! 1930 /4 /2 o lz] Mz /zo Q7 2 A A /JZ L2 "zo /Ize /za i7 3 JWM fr@ IZ M1727!! Patented Mar. 1, 1932 UNITED STATESPATENT OFFICE CRAIG V. MORTON, OF DAYTON, OHIO, ASSIGNOR TO DELCO PRODUCTS CORPORATION, i

DAYTON, OHIO, A CORPORATION OF DELAWARE l CHABGE FORMING DEVICE Application filed January 21, 1930.- SeriaLNo. 422,426.'

buretors, yeach of which delivers a ,primary mixture of air and fuel to one of a plurality of secondary mixing chamberslocated adjacent the engineintake ports and in which the primary mixture is mixed with additional air under certain operating conditi-ons.

Y livered to the cylinders from a point A. device of this character isY shown in the copending application of Fred E. Aseltine, Carl H. Kindl and Wilford H. Teeter, Serial No. 288,683,flled June 27, 1928.'

It has been found desirable in devices of the character disclosed in the `above mentioned application, to celerating the flow through the secondary mixing chamber past the end of the primary mixture delivery conduit to effect the necessary velocity of flow through the primary mixture passages and through the secondary mixing chambers in order to enable the engine to accelerate better and to prevent fuel precipitating out of the mixture and collecting on the walls of the secondary mixing. chamber. If such precipitation of fuel takes place, it is diflicult to secure equaldistribution of the fuel charge to various cylinders and such precipitation is found particularly objectionable in the case of an L-head engine. In such type of engine where the fuel char e is delivered frombelow the valve instea 'of l from above the valve, there is a much greater tendency for the fuel to puddle inthe secondary mixing chamber than in the overhead valve type of engine, where the fuel is deabove the valve. In earlier devices of this same type, means have been provided to prevent the puddling of fuel in the manner describe and to effect the desired velocity of flow through the primary mixture conduits, but such means have restricted the outletbranches of the manifold to such an extent as to reduce the engine power.

It is the principal object of this invention to provide means which will increase the velocity of iiow through the secondary mixing chambers under all operating conditions suffi- 'the overhead valve type.

provide means for acciently to prevent puddling in, and which is so constructed that the areaof the passage through said 'secondary mixing of the fuel therechambers willnot be sufficiently restricted to .L

materially reduce the engine power'. While this invention is'inore particularly adapted to anvL-head engine than to any other type, [it

will be obvious that its use is not limited to an L-head engine, but willto a lesser degree.

effect 'the same desired result in. an engine of With this object in view, the invention consists in the provision of a Venturi tube in eachnoutlet branch of themanifoldwhich is automatically movable on variations of ther ,engine speed so that the positon of said Venturi tube relative to the primary mixture conduit will be varied and the restriction of the area at the delivery end of said conduit will be increased as the F.

engine speed increases and the quantity of air flowing through the secondary mixing chamber increases.

Further objects and advantages of the present invention will be apparent from the fol- M lowing description, refereiice being hadto the accompanying 'drawings wherein appreferred embodiment of one form of the present invention is clearly shown.

In the drawings f Fig. 1 is a longitudinal section through a"` charge forming device constructed accordance with the present invention. f v l Fig. 2 is a section onthe line 2 2 ofFigr 1.

Fig. 3 is a fragmentary section through a, ,Y

branchV of the manifold showing amodified form of the present invention..

ThedeviceV disclosed comprises a main air manifold 10, having three outlet' branches, the

middle branch 12 being shown herein.v Each...

outlet branch communicates with one of the d ports of a multicylinder engine and each is provided with an attaching flangev 14 for securing the manifold to the engine block in the usual vided at the inlet for securing the carburetor unit to the manifold. Y y

The carburetor unit comprises a main housing 18, having an attaching flange 2() adapted to be secured to the flange 16 by screws 22, and an air inlet coupling 24 is secured inan manner, while aflange 16 is pro-y opening in the upper wall of the housing to admit air thereto. A casting 26 in which the passages for supplying fuel to the nozzles are formed is secured to the lower wall of the housing 18 and a sheet metal fuel bowl 28, is held tight against the bottom of the housing in any desirable way.` Fuel is conducted from a main source of supply to the fuel bowl through a conduit (not shown) and the "flow Yof fuel yto the bowl is controlled bya oat 30 g in the usual manner.H

Fuel fiows from the fuel bowl to a plurality of fuel nozzles 32 in each of the primary mixing chambers 34, the construction of which is more fully describedA later.Av VFuel is conveyed to the lnozzles by a vertical fuelv Vpassagef36 to which fuel is admitted at all engine speeds'vby a fixed orifice 38and at high spe-eds by an orifice 40 controlled by a .valve 42, which is operated in the manner described in the above mentioned application.

The passage 36 connects with a horizontal fuel canal 44, supplying fuel to all of the primary ,fuel nozzles, while at they junction ofthe passages 36 and 44, there is formed an enlarged chamber 46 in which is received a check valve 48`adapted to seat on the bottom of the chamber and prevent downward flow of fuel through the passage 36 whenever the suction in the mixing chambers falls', as for instance following a closing movement of the throttle. Each fuel nozzle is provided witha main fuel outlet 50 in the top of the nozzle and a secondary fueloutlet comprising two orifices 52 and 54 in the vertical wall of the nozzle near the bottom of the mixing chamber. At

intermediate and high speeds, they suction in the mixing chambers effect-s a flowof fuel from the main fuel outlet as well as from the secondary fuel outlets, but at idling or low speed operation under load, the suction is enough to lift fuel vonlyto a point between y is provided with a restricted fuel metering the main and secondaryv fuel outlets, fuel flowing from the latter by thea'ction of gravity under such conditions. Each nozzle orifice 56.

The primary mixing chambers constituteV i the large anterior ends of the primary mixture passages 58 which are parallel and close together, as indicatedin Fig. 2. When the,

. carburetorit attached to the manifold, these passages register with conduits which convey the primary mixture tothe secondary mixi ng chambers, as disclosedV in the above mentioned application, the tube 60, fixed in the branch 12 of the, manifold, constituting the conduit for supplying primary mixture to the secondary mixing chamber iii that particular manifold branch. A restriction 62 is provided in each of the primary'inixture passages immediately in advanceof the fuel nozzles so as to reduce the velocity-of How past said nozzles for a purpose fully'set forth in the gagement with Vthe valve, by means fully 'journalled inthe housing.

spring 72, received between the valve and ange 74, projecting from a sleeve 76, slidably mounted on a sleeve 78, fixed in the housing and guiding the stem 80, .to which the air valve is secured. The carburetor is adapted to be choked to facilitate starting of the engine by lifting the sleeve 76 into endescribed in the above application. Sufficient air to carry the starting fuel to the inta ie ports is admitted through a slot 82 formed in a plate 84 secured to the main housing.V The valve 68 admits air to a main air chamber 86 from which air iiows to thev priiiiarj,r mixing chambers through an opening 88v in the bottom of the air chamber and to the secondary mixing chamber through a passage 90, which connects with the inlet of the manifold l0. Thel iiow of air through this passage iscontrolled by a manually operable valve92 and a suction operated valve 94 securedV to shafts 96 and 98 respectively,

.f .100 The operating connections for the throttle and the valve 92forin no part of the present invention and, therefore, are not described hereiin; it being suiiicient for the purposes of this Ydisclosure to say that the primary ,105 `throttle opera-tes the valve 92 through the' v*medium of an adjustable lost motion connection which permits `a predetermined movenient of the throttle independent vof the valve 92 and is generally adjusted so as to permit 110 the primary throttle to be moved to a position corresponding to a vehicular speed of approximately 20-25 miles per hour on the level without any accompanying movement of the valve 92. On further opening of the pri-v mary throttle, the valve 92is moved siniultaiieous'ly therewith. f

On any increase of suction in the main air chamber, the valve 68 is opened to admit additional air and the opening of this valvelgo must be retarded to prevent fluttering of the valve-fand to restrict the admission of air suiiiciently to enrich the mixture to some extent 4during the acceleration period. For this purpose a dashpot is provided compris-125 ing a cylinder 100, which receives fuel from the main fuelreservoir, Aand a piston 102 slidable therein and secured to the stem of the air valve. The specific construction of the u dashpot is not material to thepresent invendisclosed herein but is fullj.7 described inthe abo-ve application, is provided to retard the opening of this valve to aid in enriching the mixture during the acceleration period, as is fully set forth 11i said application. In addition to the retardation of the opening of the valve `94, it has been found desirable to provide a fuel pump which is operative to sup-l ply additional fuel to the primary mixturej passages during the acceleration period. The above described dashpot which controls the opening of the main air pump and a fuel delivery conduit 104 coniiects with the dashpot cylinder as shown in Fig. 1 and conveys fuel channel 106, formed in a block 108,*attached to the lower wall of the main housing` and communicating with vertical passages 110,v

there being three of these passages, one of which supplies fuel to each of the primary mixture passages 58. This mechanism forms no part of this invention and is fully described in the above mentioned application.

As has been stated above, it is desirable to provide means for accelerating the flow through the primary mixture passages s0 that the enriched mixture following an opening of the throttle will be delivered to the secondary mixing chambers almost iinmediately after the throttle opens in order to secure smooth and rapid engine acceleration and to also produce a high velocity of flow through the secondary mixing chambers in order to prevent precipitation of fuel from the mixture and puddling of fuel on the w alls of said secondary mixing chamber. Heretofore, Venturi tubes have been positioned in the outlet branches ofthe manifold, such Venturi tubes forming the secondary mixing chambers and effecting a relatively rapid rate of flow therethrough. These Venturi tubes, in earlier forms of this device, been fixed in position with the throat of the Venturi tube adjacent the outlet of the primary mixture conduits. These devices are open to the objection that if the Venturi tube is made sufficiently small at the throat to produce the desired acceleration of flow when the throttle is only slightly opened and a small quantity of air passing through the tube, such tube will restrict the flow when the throttle is relatively wide Aopen to such a degree that a relatively highpartial vacuum is created within the tubes and a' consequent reduction in engine power results.

According to the present invention, Venturi tubes are employed-in the outlet branches of the primary manifold and such tubes are normally positioned, when the throttle 'is closed or nearly closed, so that the throat is valve is utilized as a 1 to a horizontal fuel have I the venturi.

closelyadjacent thefoutlet of the primary mixture conduit.v These Venturi tubes, however,5are automatically movable as the quantity of air passing` through the said Venturi tubes increases with the opening of the throttle, so' that the throats of the kVenturi tubes are moved away from the end of the primary mixture conduit and the area of the available passage through which air must fiow is increased in accordance with the increase in opening of the throttle.

For this purpose, each outlet branch of the manifold is provided with a sleeve 120, which fits relatively tightly within the inanifold branch and at its end adjacent the en-r` gine, is bent over as shown in Fig. 1 to form an inner sleeve 122, a space 124 being provided between the two sleeves. A 4Venturi tube 126 is slidably mounted within the sleeveV and is provided with a cylindrical extension 128 lwhich is received within the space 124 andfits relatively tightly in said space. The

sleeve 12() is adapted to be held in position by a set screw 121 or any other suitable means,

and threaded or otherwise secured in sleeve '120 is a collar 130, which limits the movement Y of the Venturi tube in one Vdirection and determines the normal position when the engine is not running. Received within the space 124 between the end of the cylindrical extension 128 and the closed end of the sleeve 120 is a spring 132, which normally moves the Venturi tube into engagement with the 'collar 130. Holes 134 are provided in the inner sleeve 122 to permit the escape of air from: the space 124. As above stated, the cylindrical extension 128 fits relatively tightly within the space 124 so that such extension and the space constitute an air dashpot which retards the movement of the VenturiI v tube in either direction of its movement, the

tube being enabled to move only as rapidly 'as the air can pass out of or into the space 12,4 through the orifices 134vand by leakage Varound the extension 128.

The operation of this device should be obvious on inspection. Normally, the Venturi tube is in the position shown in Fig. 1 with the throat-of the tube adjacent the end of the primary mixture conduit. If the throttle is opened, a greater quantity of air flows through the venturi and this air in Yconjunction with the suction of the engine, moves the venturi to the right in Fig. 1, and the throat of the venturi away from the end ofthe primary mixture conduit, increasing the area of the passage betweensaid conduit and The vmotion of the venturi is retarded by the action of the above described air dashpot so that the movement of the ven# turi is gradual and no damage to .the parts is effected due to the rapid pulsations of the engine and consequent rapid changes in suction. As the throttle is moved toward closed position, the venturi is gradually moved in the `oppositedirection until it lreaches the position shown in Fig. 1. This-device, therefore, acceleratesthe flow through the secondary mixing chambers at all times when the engine is running, but since the area of the passage therethrough is increased as the v. quantity of `air flowing through the chamber lis increased, the partial vacuum maintained therein is held substantially constant and the power of the engine is not reduced.

In Fig. 3 is shown a somewhat modified form of the above described means for accelerating the air flow through the secondary 'mixing chamber and in this form the venturi is provided With a cylindrical eXtensionHO at its rear end which slides Within a spacelt similar to the space 124.-. This spa-ce is also provided with a springflll, Which in conjunction with the spring 132, causes the venturi to be in effect, a floating venturi, its normal position being determined by the relative strength of the two springs so that the venturi comes to rest When the springs reach a condition of balance. Y Y l While the form of embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming Within the scope of the claims which follow.

lfVhat is claimed is as follows:

l. An intake manifold for a multicylinder internal combustion engine having a plural- ,ity of intake ports, comprising a plurality of Outlet branches adapted to communicate with said intake ports, movable means adapted to reciprocate in said branches for controlling the velocity of flow therethrough and means for cushioning the .movement of movable means in both directions of its movement.

2. An intake manifold for a multicylinder internal combustion engine having a plurality of intake ports, comprising a plurality of outlet branches adapted to communicate With said intake ports, movable means in said branches for controlling the velocity of flow therethrough, and a dash-pot for ret-arding the movement of said movable means.

3. An intake manifold for a multicylinder internal combustion engine having a plurality of .intake ports, comprising a plurality of outlet branches communicting With such ports, conduits adapted to supply fuel to said manifold branches, a movable member in each of said branches adapted to regulate thevelocity of flovv past the ends of said conduits, means normally holding said member in position to Vrestrict the passage through said outlet branch at a point adjacentl the outlet of said fuel supply conduits and means for retarding the movement of said movable member.

4. An intake manifold for a multicylinder internal combustion engine having a plurality of intake ports, comprising a plurality of V'outlet branches communicating With such the end of said ports, conduits adapted to supply fuel to said manifold branches, a movable member adapted to be moved toward and away from the outlet end of each of said fuel delivery conduits to regulate the velocity of flow past conduit, and means for retarding the movement of said movable mem.- ber in both its directions ofmovement.

5. An intake manifold for a multicylinder internal combustion engine having a .plurality of intake ports, comprising a plurality of outlet branches communicating with such ports, fuel delivery conduits projecting int-o the outlet branches of said manifold, a movable member in each of said branches havingv a restriction therein, and means normally holding each of said member in such position that the restriction therein is adjacent the outlet end of its associated fuel delivery conduit.

6. An intake manifold for a multicylinder internal combustion engine having a plurality of intake ports, Vcomprising a plurality 0f outlet branches communicating with such ports, fuel delivery conduits projecting into the outlet branches of said manifold, a movable member in each of said branches having a restriction jthereimvrneans normally holding each of said members in such position that` the restriction therein is adjacent the outlet end of its associated fuel delivery conduit, and means for retarding the movement of said movable members.

l An intake manifold for a multicylinder internal combustion engine having a plurality of intake ports, comprising a plurality of outlet branches communicating with such ports, fuel delivery conduits projecting into the outlet branches of said manifold, a mov-A able member is each of said branches having a restriction therein, said members being normally positioned so that the restriction therein is adjacent the outlet end of the fuel delivery conduit, and adapted to be moved byl engine suction to vary the area of the passage at the end of said fuel delivery conduit.

8. An intake manifold for a multicylinder vinternal `combustion engine having a plurality of intake ports, comprising a plurality of outlet branches communicating with such' ports, fuel delivery conduits projecting into the outlet branches of said manifold, and movable Venturi tubes Within said branches surrounding said conduits, said Venturi tubes normally being positioned so that the throats thereof are adjacent the associated fuel delivery conduits.

9. An intake manifold for a multicylinder internal engine having a plurality of intakel ports, comprising a plurality of outlet branches communicating with such ports, fuel delivery conduits projecting into the outlet branches of said manifold, suction operated Venturi tubes in said manifold sur rounding said conduits and adapted to be loo moved as the engine speed varies to vary the size of the passage'betWeen each fuel delivery conduit and its associated Venturi tube.

10. An intake manifold for a multicylinder internal combustion engine having a plurality of intake ports, comprising a plurality of outlet branches communicating With such ports, fuel delivery conduits projecting into the outlet branches of said manifold, suction operated Venturi tubes in said manifold surrounding said conduits, and means for retarding the movement of said Venturi tubes. y

11. In combination with the intake pipe of an internal combustion engine having yan intake port, a conduit for supplying a primary mixture of fuel and air to `said intake pipe and means in said pipe for increasing the velocity at Which the mixture is delivered from said intake pipe to the intake port, said means comprising a movable passage restricting member and means for retarding the movement thereof. f

12. In combination with the intake pipe of an internal combustion engine having an intake port, a conduit'for supplying a primary mixture of fuel and air to said intake pipe and means in said pipe for increasing the velocity at which the mixture is delivered from said intake pipe to the intake port, said means comprising a movable Venturi tube, adapted to variably restrict the pipe as it moves to different positions.

13. In combination with the intakepipe of an internal combustion engine having` an intake port, a conduit for supplying a prin mary mixture of fuel and air to said intake pipe and means in said pipe for increasing the velocity at which the mixture is delivered' from said intake pipe to the intake port, said means comprising a suction operated Venturi tube adapted to be moved to different positions as the engine speed varies.

14. In combination with the intake pipe of an internal combustion engine having an intake port, a conduit for supplying a primary mixture of fuel and air to said intake pipe and means in said pipe for increasing the velocity at Which the mixture is delivered from said intake pipe said means comprising a movable Venturi tube adapted to variably restrict the pipe and means for retarding the movement of said Venturi tube.

15. In combination With the intake pipe of an internal combustion engine having an intake port, a conduit for supplying a primary mixture of fuel and air to .said intake pipe and means in said pipe for increasing the velocity at Which the mixture is delivered from said intake pipe to the intake port, said means comprising a movable Venturi tube adapted to variably restrict the pipe,

other end of the sleeve to the intake port,

means for retarding the movement of said Venturi tube and means for returning the said tube to its normal position.

16. In combination with the intake pipe of an internal combustion engine 'having an intake port, a conduit for supplying a primary mixture of fuel and air to said intake pipe and means in said pipe for increasing the velocity at which the mixture is deliv.-

ered from said intake pipe to the intakev port, said means comprising a movable Venturi tube adapted to variably restrict the pipe, an outer sleeve in which said tube is slidable, an inner sleeve parallel to said outer sleeve throughout part of its length and spaced therefrom, a projecting' portion of the Venturi tube extending into the space thus formed, means closing the other end of said space and means permitting only a limited passage of air to and from space whereby it acts as a dashpot to retard the movements of the Venturi tube.

17. In combination with the intake pipe of an internal combustion engine, of a removable unit adapted to be inserted in said pipe adjacent its outlet end to control the velocity of flow through said pipe into the intake ports, said unit comprising a sleeve fitting Within the intake pipe, a Venturi tube slidable Within the sleeve, means positioned at one end of the sleeve to retard the movement of said Venturi tube, a stop at the for determining the normal position of the venturi and means for retaining the sleeve in position in said intake pipe. Y

In testimony whereof I hereto aflix my signature.

CRAIG V. MORTON.

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