US1846381A - Charge forming device - Google Patents

Description

Feb. 23, 1932. F. E. ASELTINE CHARGE FORMING DEVICE Filed April 2, 1930 2 Sheets-Sheet 51 d'selii F. E. ASELTINE CHARGE FORMING DEVICE Filed April 2, 1930 2 Sheets-Sheet ax hi Q Q u ww w, 4% JM'WM Sfifi ltd lid

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Patented Feb. 23, 1932 UNITED STATES PATENTFOFFICE FRED E. A8ELTINE, OI DAYTON, OHIO, ASSIGNOR 'IO DELOO PLODUUI'B CORPORATION,

01 DAYTON, OHIO, A CORPORATION OF DELAWARE CHARGE FORMING DEVICE Application filed April 8, 1880. Serial No. 1,004.

This invention relates to charge formin devices for internal combustion engines, an more particularly to devices of the character which comprise a plurality of primary carburetors, each of which delivers a primary mixture of air and fuel to one of a plurality of secondary mixin chambers located adjacent the engine inta e ports and in which the primary mixture is mixed with additional air under certain operating conditions.

A device of this character is shown in the copcnding application of Fred E. Aseltine, llarl H. Kindl and Wilford H. Teeter, Serial No. 288,683, filed June 27, 1928.

When devices of the character above described, are employed with engines in which each intake port supplies fuel mixture to two adjacent cylinders, difficulties have arisen in securing equal distribution of the fuel to the cylinders of each pair because of the irregularity of the firing order of the engine. For instance, a Buick six-cylinder engine has a firing order of l, 4, 2, 6, 3, 5, the numbers referring to the engine cylinders, It will be clear, therefore, that between the firing of cylinders l and 2, only one cylinder fires, whi e between the firing of the cylinders 2 and 1, three cylinders fire. In devices of this character, whenever any cylinder fires the suction communicated to the manifold by the engine piston is transmitted to some extent to all the manifold branches a lesser degree of suction being communicated to those branches which do not communicate with the cylinder in which that particular piston is located. Thus, in the case of the Buick engine, when cylinder 4 fires subsequent to cylinder 1, there is some degree of suction created in the manifold branch supplying fuel mixture to cylinder 1 and this results in some fuel being drawn from the primary mixture passage in that manifold branch which is deposited on the walls thereof. Also after cylinder 2 fires, suction will be communicated to the manifold branch supplying cylinders l and 2 during the firing of cylinders 6. 3 and 5, resulting in some fuel being drawn from the primary mixture tube into the outlet branch of the manifold supplying cylinders 1. and 2. It will be obvious,

therefore, that some fuel accumulates in each manifold branch during the firing of every cylinder exce t those with which that particular manifold ranch is directly associated and in the case of cylinders 1 and 2, substantially three times as much fuel will accumulate in this manner prior to the firing of cylinder 2 as before the firin of cylinder 1. As a result of this function, 1; e mixture supplied to cyl-, inder 2 willbe rich by comparison to that supplied to cylinder 1, such unequal mixture distribution will cause somewhat uneven operation of the engine and possibly missing of some of the cylinders.

It is an object of this invention to eliminate the difiiculty above described and to provide means which will effect ual distribution of the fuel to the cylinderso each pair supplied by any intake port.

According to the present invention, this object is accomplished by the provision of a valve in each of the primary mixture tubes which delivers mixture to the outlet branches of the manifold, such valves being constructed so that each valve will be automatically closed during the suction stroke of all the engine pistons except the istons of those cylinders which are supplie with fuel on that particular primary tube in which the valve is located, while each valve is o sued to permit a flowof primary fuel mixture through its associated tube on the suction stroke of the pistons in the cylinders supplied with fuel by that particular tube.

Further objects and advantages of the pres ent invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred embodiment of one form of the present invention is clearly shown.

In the drawings:

Fig. 1 is a plan view of a charge forming device in which the present invention is involved and showing certain parts in section.

Fig. 2 is a section on the line 2-2 of Fig. 1. 95

Fig. 3 is a fragmentary section on the line 3-3 of Fig. 2.

Fig. 4 is a fragmentary section .on the line H of Fig. 1.

Fig. 5 is a corresponding section showing a modified form of the device.

Fi s. 6 and 7 are fragmentary sections on the lines 66 of Fig. 4" and 7 -7 of Fig. 5.

The device disclosed comprises a main air manifold 10, having three outlet branches 12, 14 and 16, each of which is provided with a flange 18 for securing the manifold to the engine block in the usual manner while a flange 20 is provided at the manifold inlet for securing the carburetor unit thereto.

The specific construction of the carburetor unit is entirely immaterial so far as the present invention is concerned, but for convenience, a carburetor unit is shown in the drawings which is substantially similar to that disclosed in the earlier application above referred to. This carburetor unit comprises a housing 22 having an attaching flange 24 adapted to be secured to the flange 20 by screws 26 and an air inlet coupling 28, which admits air to an opening in the upper wall of the housing. A casting 30, in which the fuel supply passages are formed, is secured to the lower wall of the housing 18 and a sheet metal fuel bowl 32 is held tight against the bottom of the housing by a screw 34 screwed into the casting 30. A float 36 controls the I flow of fuel into the fuel bowl and is adapted to maintain a substantially constant level herein in the usual way.

A plurality of fuel nozzles 38 located in the primary mixing chambers 40, more fully disclosed hereinafter, are supplied with fuel by a vertical fuel passage 42 in the casting 30, fuel being admitted thereto at all engine speeds through a fixed orifice 44 and at relatively high speeds by an orifice 46 controlled by a valve 48 operated as described in the above mentioned application. The passage 42 connects with the horizontal canal 50 supplying fuel to all of the fuel nozzles 38, while at the junction of the passage 42 and canal 50 there is formed an enlarged chamber 52, in which is received a check valve 54 adapted to seat on the bottomof the chamber to prevent downward flow of fuel through the pas sage 42 on any reduction of suction in the mixing chamber. Each fuel nozzle is provided with a main fuel outlet 56 from which fuel is drawn at relatively high speeds and a secondary fuel outlet, comprising two orifices 58 and 60 in the vertical wall of the nozzle near the bottom of the mixing chamber, which is effective at all times to supply fuel in the manner described in the above mentioned application. Each nozzle is provided with a restricted fuel metering orifice 62.

The primary mixing chambers constitute the'enlarged anterior ends of the primary mixture passages 64, which are parallel and close together as indicatedin Fig. 3. lVhen the carburetor is attached to the manifold, these passages register with conduits which convey the primary mixture to the secondary mixing chambers. These conduits, at their delivery ends, com rise tubes 66, 68 and 70 fixed in the outlet branches of the manifold 12, 14 and 16 respectively. The middle tube 68 communicates directly with the associated primary mixture passage 64, while the tubes 66 and 70 connect with pipes 72 and 74 respectively, which communicate respectively with passages 76 and 78 indicated in dotted lines in Fig. 1. These passages register, when the device is assembled, with the two outer primary mixture passages 64. This structure is full described in the above mentioned application and forms no part of the present invention. Restrictions 80 are provided in each of the primary mixture passages immediately posterior to the fuel nozzles so as to reduce the velocity of flow past said nozzles for the purpose set forth in the above application.

A single throttle valve 82 extends across all of the primary mixture passages and controls the flow therethrough, being provided with grooves 84 which register with said passages. The operating mechanism for the throttle is not disclosed in detail herein since it forms no part of this invention, but the manner of its operation will be referred to later to facilitate a complete understanding of the whole device.

Air is admitted through the coupling 28 and is controlled by a valve 86, normally held against a seat 88 by,a spring 90, received between the valve and a flange 92, projecting from a sleeve 94, slidable on a sleeve 96, fixed in the housing 22 and guiding the stem 98 to which the air valve is secured. In order to aid in starting, the air valve is held closed by a lever 100 which projects beneath the flange 94 in a manner fully described in the above application. Air to carry the starting fuel to the engine cylinder is admitted through a slot 102 in a plate 104. secured to the housing 22. The valve 86 admits air to a main air chamber 106, from which air flows to the primary mixing chambers through an opening108 in the bottom of said chamber and to the secondary mixing chambers hereinafter described, through a passage 110 controlled by manually and suction operated valves 112 and 114 respectively, secured to shafts 116 and 118 respectively, which are j ournalled in the housing 18.

It is sufficient for the purposes of this disclosure to state that the primary throttle opcrates the valve 112 through the medium of a lost motion connection, which is adjustable to permitany predetermined movement of the throttle independent of the valve 112 and is generally adjusted so as to allow the 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 112. On

further opening of the throttle, the valve is moved simultaneously therewith.

On any increase of suction in the main air chamber, the valve 86 is opened to admit additional air and the opening of this valve must be retarded to prevent fluttering and to restrict the admission of air sufiiciently to enrich the mixture to some extent during the acceleration period following an opening of the throttle. For this purpose there is provided a dashpot comprising a cylinder 120, formed in the casting and a piston 122 secured in any desirable manner to the lower end of the valve stem 98, and slidable within the cylinder. The specific construction of the dashpot is, however, not material'and any conventional form of dashpot may be employed so far as the present invention is concerned.

its previously stated, the valve 114 is suction operated and a dashpot is provided to retard the opening of this valve to restrict the admission of air to the secondary mixing chambers so as to aid in enriching the mixture during the acceleration period. This dashpot is not disciosed herein, but is fully illustrated and described in the above application and its function is also fully described therein. In addition to retarding the opening of the valve 114, as above described, it has been found necessary to supply additional fuel to the primary mixture passages during the acceleration period. For this purpose the dasbpot controlling the main air valve is designed to act as a pump, a fuel delivery conduit 124 being provided which communicates with the cylinder 120 near the bottom and delivers fuel to fuel passage 126 in a distributing block adapted to distribute fuel to three vertical passages 128, which communicate with the primary mixture passages and supply fuel thereto, as described in the earlier application. This pump constitutes no part of the invention and is described herein merely to facilitate understanding of the operation of the device as a whole.

The tubes 66, 68 and 70 comprising the delivery ends of the primary mixture conduits, deliver fuel to the secondary mixing chambers formed in the outlet branches of the manifold and comprising Venturi tubes so positioned that the most restricted part of each tube is positioned adjacent the delivery ehd of the primary mixture delivery conduit with which it is directly associated. These Vcnturi tubes 'are identical in form and tube 130 which is associated with the tube 68, is disclosed in Fig. 2. Each Venturi tube is provided with a rib 132 which. when the device is assembled, is adapted to be clamped between shoulders 134 and 136 on the manifold and the engine block respectively. to hold "the tube in position. These tubes are of the same construction as shown in the above application and are more fully described there- 1n.

As indicated herein before, it has been found that where each outlet branch of the manifold supplies two adjacent cylinders with combustible mixture through a single intake port, one of said cylinders has a tendency to be supplied with too rich a, mixture, while the other of said pair of cylinders is provided with too lean a mixture, this being due to the fact that when every cylinder other than those directly supplied by any particular manifold branch under consideration is firing, there is some suction communicated to the primary mixture tube which delivers to that particular outlet branch and some delivery of fuel therefrom to its associated manifold branch. Since the number of cylinders which fire between the firing of the two cylinders of a pair, is different; the amount of fuel which is drawn into the outlet branch of the manifold during the firing of said other cylinders is also diiferent and the fuel accumulated in the manifold branch prior to the firing of the two cylinders of the pair is not the same, resulting in the undesirable function above re ferred to. For instance, if cylinders 1 and 2 be considered specifically, it will be found that where the engine has a firing order of 1, 4, 2, 6, 3, 5, only cylinder 4 fires between cylinders 1 and 2, while cylinders 6, 3 and 5 fire between 2 and 1. Due to the fact that the suction is communicated to the outlet tube 66 to some extent during the firing of the cylinders 4, 6, 3 and 5, it will be obvious that there will be some accumulation of fuel in the outlet branch 12 of the manifold dur ing the firing of the above mentioned fourcylinders. It is obvious, however, that be tween the firing of the cylinders 1 and 2, there will be only about one-third the accumulation of fuel as between the firing of cylinders 2 and 1, hence, a greater amountof fuel will be supplied to cylinder 1 than to cylinder 2. This results in various difliculties such as irregularity of operation, reduction in engine power and other disadvantages, because of unequal fuel distribution. These difficulties are eliminated by means of the present invention which comprises a plurality of valves 140, there being three of these valves of identical construction, one of which is positioned in each of the tubes 66, 68 and 70. Each valve 140 is secured by screws 142 to a spindle 144, rotatably mounted in the walls of the tube. Secured to the spindle outside of the primary mixture tube is an inverted U-shaped member 146, having one leg longer than the other in one form of the device as shown in Fig. 5, and ex-- tending to a position considerably below the spindle, as indicated at 148. This depending leg 148 is provided with a pin 150 to which is connected one end of a spring 152,.the other end of which is connected to a pin 15 k on the primary mixture tube and is effective to hold the valve in closed position, as shown in Fig. 5, and to move said valve to closed 5 position. The member 146 is formed integral with a bafiie 156.which is bent so as to extendupwardly in the outlet branch of the manifold and is adapted to open the valve 140 when the secondary air passage is opened branches at relatively high velocity. This air will strike the battle and will open the valve 140 against the tension of the spring 152. It will be understood that the valves are opened only when the piston in one of the cylinders of the pair supplied with mixture by any articular manifoldoutlet branch is making its suction stroke.' At all other times, there is no flow of air through any manifold outlet branch toward its associated engine cylinder. It will be clear, therefore, that as soon as the suction stroke of the piston in either of the cylinders supplied with fuel mixture by any particular manifold branch tenninates, the spring 152 willbe effective to close the valve 140 in the primary mixture tube associated with that particular branch, and although a suction is created as previously disclosed, in all branches of the manifold whenever any piston is making its suction stroke, the valves 140 in those tubes which do not communicate directly with that cylinder in which the piston is making a suction stroke, will be closed. No fuel can, therefore, be drawn from any primary mixture tube except during the suction stroke of a cylinder supplied with mixture directly by such primary tube and the accumulation of fuel in the manifold outlet branches as previously 40 disclosed, is avoided and substantially uniform distribution of the fuel is secured. This will result in smoother engine operation, greater power and other advantages.

In the other form of the device which is shown in Figs. 1 to 4 and 6, the U-shaped member 146 is not provided with the extension 148 and the spring 152 is not provided to close the valve, the latter being closed by the action of gravity, the weight of the vane 156 being sufficient to swing the valve-to closed. position when the blast of air through the secondary mixture passage ceases on the closing of the engine intakevalve in the .port supplied by anv particular secondary mixturepassages.

The form having the spring152 is prob-ably the preferable form, since the-spring will effect a more rapid and more positive closing of the valve. 1 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.

\Vhat is claimed is as follows:

1. A charge forming device for multi-cyland air moving through the manifold outlet inder internal combustion engines, oompris-' mg a manifold having a plurality of outlet branches adapted to communicate with the engine intake ports, said branches being in communication with each other and with the manifold inlet, means for delivering fuel to each outlet branch of said manifold, and means for preventing the delivery of fuel to any of said manifold branches at all times except while an intake valve associated with that particular manifold branch is open.

2. A charge forming device for multi-cylinder internal combustion engines, comprising a manifold having a plurality of outlet branches adapted to communicate with the engine intake ports, said branches being in communication with each other and with the manifold inlet, normally ineffective means for delivering fuel to said outlet branches, and means for rendering said fuel delivery means in any particular branch effective only when the intake valve associated with that particular branch is open.

4 3. A charge forming device for multi-cylinder internal combustion engines comprising a plurality of mixing chambers, each of which delivers mixture to one of the intake ports and is adjacent its associated port, said mixing chambers being in communication with each other, means for delivering fuel directly to said mixing chambers, and means for preventing the delivery of fuel to any one of said mixing chambers at all times other than when the intake valve controlling its associated intake port is open.

4. A charge forming device for multi-cylinder internal combustion engines comprising a plurality of secondary mixing chambers each of which delivers mixture to one of the engine intake ports and is adjacent its associated port. said mixing chambers being in communication with each other, means for de livering a primary mixture of fuel and air to each of said secondary mixing chambers, means admitting air to said secondary mixing chambers, and means for preventingt-lre de livery of primary mixture to any one of-said secondary mixing chambers at all times other than when the intake valve controlling its associated intake port is open.

5. A charge forming device for multi-cylinder internal combustion engines comprising, a plurality of secondary mixing chambers each of which delivers mixture to one of the engine intake ports and is adjacent its associated port, a plurality of primary m xing chambers, each of which is adapted todeliver a primary mixture of fuel and air to one of said secondary mixing chambers, means admitting air to said secondary mixing chambers, and means for preventing the delivery of primary mixture to any one of said secondary mixing chambers at all times other than when the intake valve controlling its associated intake port is open.

6. A charge forming device for multi-cylinder internal combustion engines comprising, a plurality of secondary mixing chambars in communication with each other, each of which delivers mixture to one of the engine intake ports and is adjacent its associated port, conduits for delivering fuel to said secondary mixing chambers and valves in conduits for controlling the delivery of fuel therefrom.

7. A charge forming device for multi-cyh inder internal combustion engines comprising, a plurality of secondary mixing chambers in communication with. each other, each of which delivers mixture to one of the engine intake ports and is adjacent its associated port, conduits for delivering fuel to said secondary mixing chambers and suction operated valves in said conduits for controlling the delivery of fuel thcrethrough.

8. A charge forming device for multi-cylinder internal combustion engines comprising, a plurality of secondary mixing chambers in communication With each other, each of which delivers mixture to one of the engine intake ports and is adjacent its associated port, conduits for deliveringfuel to said secondary mixing chambers, normally closed valves in said conduits and means for opening the valve in any one of said conduits only "when the engine intake valve which controls the port supplied with fuel by that particular conduit is open.

9. A charge forming device for multi-cylindcr internal combustion engines comprising, a plurality of secondary mixing chamers in communication with each other, each of which delivers'mixture to one of the engine intake ports and is adjacent its associated port, conduits for delivering fuel to said secondary mixing chambers and independently operable valves in said conduits for controlling the flow of fuel therethrough.

10. An intake manifold for a multi-cylinder internal combustion engine having a plurality of intake ports, comprising a plurality of outlet branches associated with said ports and delivering a combustible mixture thereto, said branches being in communication with each other, an air inlet admitting air to the manifold, conduits adapted to deliver a primary mixture of fuel and air to said manifold branches, and means for preventing the delivery of fuel mixture from any one of said conduits at all times other than when the intake valve controlling the port to which that particular conduit supplies mixture is open.

ll. An intake manifold for a multi-cylinider internal combustion engine having a plurality of intake ports, comprising a plurality of outlet branches associated with said ports and delivering a combustible mixture there to, said branches being in communication With each other, an air inlet admitting air to the manifold, normally closed conduits adapted to deliver a primary mixture of an and fuel to said manifold branches, and means for renderin said conduits effective only when the inta e valve controlling the port to which that particular conduit supplies mixtureiso n. v

12. An intake manifold for a multi-cylinder internal combustion engine having a plurality of intake ports, comprising a plurality of outlet branches associated with said ports and delivering a combustible mixture there to, said branches being in communication with each other, an air inlet admitting air to the manifold, conduits adapted to deliver a primary mixture of fuel and air to said manifold branches, and valves in said conduits for controlling the delivery of primary mixture to the manifold branches.

18. An intake manifold for a multi-cylin der internal combustion engine having a plurality of'intake ports, comprising a plurality of outlet branches associatedvvith said ports and delivering a combustible mixture thereto, said branches being in communication with each other, an air inlet admitting air to the manifold, conduits adapted to deliver a primary mixture of fuel and air to said manifold branches, and suction operated valvesin said conduits for controlling the delivery of primary mixture to the manifold branches.

14. An intake manifold for a multiwylinder internal combustion engine having a plurality of intake ports, comprising a plurality of outlet branches associated withsaid ports and delivering a combustible mixture thereto, said branches being in communication With each other, an air inlet admitting air to the manifold, conduits adapted to deliver a primary mixture of fuel and air to said manifold branches, and normally closed, suction operated valves in said conduits for controlling the delivery of primary mixture to the manifold branches.

15. An intake manifold for a multi-cy1inder internal combustion engine having a plu rality of intake ports, comprising a plurality of outlet branches associated with said ports and delivering a combustible mixture thereto, an air inlet admitting air to the manifold, conduits adapted to deliver a primary mixture of fuel and air to said manifold I branches, a valve in each of said conduits for controlling the flow therethrough, means secured to each of said valves and operated'b the air flowing through the associated manifold branch for operating said valves.

16. Anintake manifold for a multi-cylin- -dcr internal combustion engine having a plurality of intake ports, comprising a plurality of outlet branches associated with said ports and delivering a combustible mixture thereto, 'an air inlet admitting air to the manifold, conduits adapted to deliver a primary mixto each of said valves and cham ers, conduits for con ture of fuel and air to said manifold branches, a valve in each of said conduits for controlling the flow therethrough, a vane secured projecting into its associated manifold branc said vane being operated b the air flowing through the manifold branc to operate said valve.

17. A charge forming device for multicylinder internal combustion engines comprising an air manifold having a plurality of outlet branches adapted to communicate with the engine intake ports and an inlet admitting air thereto, secondary mixing chambers formed in said outlet branches, a carburetor unit associated with said manifold and having a plurality of primary mixing chambers formed therein, means for supplyin fuel and air to said rimary mixing ucting the primary mixture to said secondary mixing chambers, and valves in said conduits adjacent the outlet ends thereof for controlling the flow of mixture therethrough.

18; A charge forming device for multicylinder internal combustion engines comprising an air manifold having a plurality of outlet branches adapted to communicate with the engine intake ports and an inlet admitting air thereto, secondary mixing chambers formed in said outlet branches, a carburetor unit associated with said manifold and havin a-plurality of primary mixing chambers ormed therein, means for supplying fuel and air to said primary mixin 0 ambers, a plurality of conduits each 0 which connects primary mixing chamber with one of the secondary mixin chambers, and indeendently operable va ves in said conduits or controlling the supply of primary mix ture to the secondary mixing chambers.

19. A charge forming device for multicylinder internal combustion engines comprisin an air manifold having a plurality of outlet ranches adapted to communicate with the engine intake ports and an inlet admitting air thereto, secondary mixing chambers formed in said outlet branches, a carburetor unit associated with said manifold and having a pluralityA of primary mixing chambers formed t erein, means for supplying fuel and air to said primary mixing chambers, conduits for conducting the primary mixture to said secondary mixing chambers valves in the outlet ends of said conduits, an means controlled by the suction in the secondary mixing chambers for operating said valves.

In testimony whereof I hereto aflix my signature.

FRED E. ASELTINE.

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