US1842816A - Charge forming device - Google Patents

Description

J n, 1 5; 19 2- F. E. ASELTINE 1 CHARGE FORMING D EVI CE F iled Jan. 2, 1950 3mm Jred 6 dseltim? Patented Jan. 26, 1932 STATES PATENT OFFECE.

FRED E. ASELTINE, OF DAYTON, OHIO, ASSIGNOR T DELCO PRODUCTS CORPORATION, OF DAYTON, OHIO, A CORPORATION OF DELAWARE CHARGE FORMING DEVICE Application filed January 2, 1930.

This invention relates to charge forming devices for internal combustion engines, and more particularly to devices of this char acter 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 mixing chambers located adja cent the engine intake ports, and in which the primary mixture is mixed with additional air under certain operating conditions.

Devices of this character are shown in the copending applications of Fred Ascltine, Carl H. Kindl and William G. Pontis, Serial No. 360.404, filed May 4, 1929 and of Fred E.

Aseltine, Serial No. 404,324, filed November 2, 1929, the present invention being an improvement on the later filed of these applications. I

It is the object of the present invention to control the proportioning of the fuel mixture by regulation of the velocity of flow past the fuel inlets, whereby a static suction may be maintained under certain operating conditions and a velocity head created at the fuel inlets, and more particularly, to provide means for controlling the velocity past the fuel inlets which is operated in accordance with the suction maintained within the mixture passage. I i

According to the present invention, this object is secured by the provision of restrictions'between the primary mixing chambers and the primary mixture passages extending therefrom. to the secondary mixing chambers,

with a valve for controlling the area of these lGStIlCQiOllS, said valve being operated by the main air intake valve, which is moved in ac-- cordance with the suction maintained within the carburetor. I

Furt ier objects and advantages of the prescnt invention will be apparent from the following description, referencebeing 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 longitudinal, vertical section through a charge forming device construct-ed according to the present invention. 7

Serial No. 418,033.

Figs. 2 and 3 are sections on the lines 2-2 and 33 of Fig. 1 respectively.

The device disclosed comprises a main air manifold having three outlet branches, the middle branch-l2 beingshown herein. Each outlet branch communicates with one of the ports of a multicylinder engine, and each is provided with an attaching flange for securing the manifold to the engine block in the usual. manner, while the flange 14 is provider at the manifold inlet for securing the carburetor unit to the manifold. The carburetor unit comprises a main housing 16, having an attaching flange 18 adapted to be secured to the flange 14 by screws 20, and an air inlet coupling 22 is secured in an opening in the upper wall of the housing in any suitable way and may be connected with an air cleaner if desired. A casting 24, in which the passages supplying fuel to the nozzles are formed, is secured by screws to the lower wall of the housing 16 and a sheet metal fuel bowl 26 is held tight against the bottom of the housing by any suitable means. Fuel is conducted from the main source of supply to the fuel bowl through a conduit (not shown) and the flow of fuel to the bowl is controlled by a float 28 operating in. the usual manner to maintain a substantially constant level of liquid in the bowl.

Fuel flows from the bowl to high and low speed fuel nozzles 30 and 32 respectively, in each of the primary mixing chambers 33. Separate fuel passages supply the nozzles 30 and 32 with fuel, the nozzles 30 being supplied by a vertical passage 34 having a calibrated plug 36 at its lower end and communicating at its upper end with a horizontal fuel canal 38, which communicates directly with all of the nozzles 30. The fuel nozzles 32 are provided with fuel through a passage which is illustrated and fully described in the copending applications referred to above, but since this specific construction forms no part of the present invention, it is omitted herein for the sake of brevity. Each fuel nozzle 30 is provided with a main fuel outlet 40 in the top of the nozzle and a secondary fuel outlet comprising two orifices 42 and 44 in the vertical wall of the nozzle near the bottom of the to shafts 92 and 94, journalled in the housing.

mixing chamber. At intermediate and high speeds, the suction is enough to lift fuel from the main fuel outlet, but at idling or low speed operation under load, the suction is enough to lift fuel only to some point between the top of the nozzle and the orifices 42 and 44, fuel flowing from these orifices by the action of gravity under such operating conditions. The nozzles 30 and 32 are provided with restricted metering orifices 46 and 48 respectively. The primary mixing chambers are formed in the anterior ends of the primary mixture passages 50, the point of connection between the mixing chambers and mixture passages be ing restricted as indicated at 52 and provided with a valve 54 for controlling the area of said restrictions in a manner fully described hereinafter. Air passages 56' admit air to the mixture passage immediately in advance of the above mentioned restrictions.

The mixture passages are parallel and close together as indicated in Figs. 2 and 3, and when the carburetor is attached to the manifold, these passages register with conduits which convey the primarymixture to the secondary mixing chambers, as fully disclosed in the above mentioned applications, the tube 58, which is fixed in the middle branch of the manifold, constituting one of said mixture conduits and conveying the primary mixture to the secondary mixing chamber located in that particular manifold branch.

A single throttle valve 60, which extends across all of the primary mixture passages, controls the flow therethrough and is provided with grooves 62, which register with the mixture passages. The specific mechanism for operating the throttle is not illustrated herein, but its manner of operation will be briefly described later. Air is admitted to the carburetor through thecoupling 22 and is controlled by the main air valve 64, normally held against a seat 66 by a spring 68 received-between the valve and the flange 70, projecting from a sleeve 72, slidably mounted on a stationary sleeve 74, which is fixed in the main housing and guides the stem 7 6 to which the air valve is secured. A choke lever 78 isadapted to hold the air valve closed when desired, as fully setforth in the above mentioned applications. Suflicient air to carry the starting fuel is admitted when the device is choked, through slots 80 formed in the upper surface of the air valve. The valve 64 admits air to a main air chamber 82 from which it flows tothe primary mixing chambers through an opening 84 in the bottom of said air chamber and to the secondary mixing chamber through a passage 86, which connects with the inlet of the manifold 10. The flow of air through this passage is controlled by a manually operable valve 88 and a suction operated valve 90 secured, respectively,

The operating connections for the throttle and the valve 88 form no part of the present invention and will not be shown herein, it being sufiicient for the purposes of this disclosure to state that the primary throttle operates the valve 88 through a lost motion connection which permits a movement of the primary throttle independent of said valve 88. The lost motion connection is generally adjusted so as to permit the primary throttle to move to a position corresponding to a vehicu lar speed of approximately 20 25 miles per hour on a level without accompanying movement of the valve 88, while on further opening of the primary throttle, the said. valve is moved simultaneously therewith. On any increase of suction in the main air chamber, the valve 88 is opened and it is found necessary to retard the movement of this valve to prevent fluttering thereof andto restrict the admission of air to some extent in order to prevent a temporary leaning of the mixture. For this purpose, a dashpot is provided comprising a cylinder 96 and piston 98 secured to the valve stem 76. The dashpot is designed to be filled with fuel by leakage past the piston and its specific construction is entirely immaterial to the present invention, any conventional dashpot being suitable. The suction operated valve 90 is adapted to be retarded inits movements by a dashpot which is not disclosed herein, for the purpose of aiding the operation of a pump, which is operative to supply fuel to the primary mixture passages on opening movements of the throttle in order to enrich the mixture to some extent during the acceleration period. Neither this dashpot nor the pump are disclosed herein because these elements form no u part of thepresent invention and their illustration is really unnecessary. Both are fully shown and described in the above mentioned applications and the pump is adapted to supply fuel to a well 100, from which the fuel flows to vertical fuel delivery passages 102 and in which it is mixed with air, which is admitted through horizontal passages 104 to form an emulsion of fuel and air which is carried into the primary mixture passages in the manner fully disclosed in the earlier applications.

It has been found that if the restrictions between the primary mixing chambers and the associated primary mixture passages are of fixed size, it is diflicult to secure proper proportioning of the fuel and air in the mixture during all operating conditions. For instance, if the restrictions are made so small that the static suction of the air chamber is maintained t the fuel nozzles under all conditions, a tendency for the mixture to become too lean subsequent to the opening of the valves 88 and 90 has been observed, while if the restrictions are made larger, there will be a tendency for the mixture to become too rich before the opening of these valves and the velocity compensating devices have heretofore been provided to control the proportioning of the mixture under various conditions. It is the purpose of this invention to eliminate these difficulties and this is accompiished by the provision of means to variably regulate the area of the above mentioned restrictions in accordance with variations in the suction within the carburetor and particularly within the main air chamber 82. To this end the valve 54, previously referred to, has been provided to control the area of these restrictions. This valve is a cylindrical plug valve journalled in the main housing and provided with grooves 110, which register with the restrictions 52. To operate this valve, an operating arm 112- is secured in any desirable manner to a spindle 114i, projecting from one end of the valve, as illustrated in Fig. 2. The arm is provided with a slot 116 at its free en d in which is received the bent end 118 of an. operating link 120, extending upwardly and is provided at its upper end with a bentover end 122, which is adapted to project through an orifice formed in an ear 124 depending from thelower edge of the main air valve 64. V

The operation of this mechanism should be obvious. On any opening movement of the air valve 6 1, the valve 5A is moved through the medium of the operating linl; 120 and the arm 112. Normally, the valve occupies the position shown in Fig. 1 and in such position the flow from the mixing chambers into the mixture passages is so restricted by said valve that substantially static suction is maintained at the fuel nozzles. As the throttle opens with corresponding opening movement of the valve 64, the valve 54 is also opened to increase the area of the passage through which the mixture must flow from the primary mix'ng chambers into the mixture passages and eventually, these openings become large enough for some velocity head to be created at the fuel nozzles and cause a proportionate increase in suction at said nozzles which will compensate for the tendency of the suction to decrease following opening of the valves 88 and 90. By proportioning the parts in various ways substantially any desired suction conditions can be maintained at the fuel nozzles so as to proportion the mixtur in any way desired throughout the operating range of the engine.

While the form of embodiment of the pres ent 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.

What is claimed is as follows:

1. A charge forming device for internal combustion engines comprising, a mixture passage, a. mixing chamber having an outlet communicating therewith, a fuel inlet for said mixing chamberyan air chamber supplying air to said mixing chamber, a throttle in the mixture passage, and automatic means for maintaining a substantially static suction at the fuel inlet during operation under certain operating conditions and for creating a. velocity head at said inlet under other operating conditions, said automatic means comprising a mechanism for controlling the outlet of said mixing chamber in accordance with variations in the suction in said air chamber.

2. A charge forming device for internal combustion engines comprising, a mixture passage, a mixing chamber having an outlet communicating therewith, a fuel inlet for said mixing chambeiuan air chamber supplying air to said mixing chamber, a throttle in the mixture passage, and automatic means for maintaining a substantially static suction at the fuel inlet during operation under certain operating conditions and for creating a velocity head at said inlet under ther operating conditions, said automatic means comprising a valve in said outlet and means for operating said valve in accordance with the suction in the air chamber.

3. A charge forming device for internal combustion engines comprising, a mixture passage, a mixing chamber having an outlet communicating therewith, a fuel inlet for said mixing chamber, an air chamber supplying air to said mixing chamber, a throttle in the mixture passage, an air valve for controlling the admission of air to said air supply chamber and means for maintaining a substantially static suction at the fuel inlet during operation under certain operating conditions and for creating a velocity head at said air inlet under certain other operating conditions, said means comprising a mechanism for controlling the outlet of said mixing chamber and means connecting said mechanism to the air valve, for operation thereby.

4. A charge forming device for internal combustion engines comprising, a mixture passage, a mixing chamber delivering fuel mixture into said mixture passage, fuel and air inlets therefor, a valve controlling the air inlet, a throttle in the mixture passage, a restricted connection between the mixing chamber and the mixture passage, a valve in said restricted connection to regulate the flow therethrough and means for operating said valve in accordance with movements of the air valve.

5. A charge forming device for internal combustion engines comprising, a. mixture passage, a mixing chamber delivering fuel mixture into said mixture passage, fuel and air inlets therefor, a valve controlling tie air inlet, throttle in the mixture passage,

a restricted connection between the mixing chamber and the mixture passage, a valve 'in said restricted connection to regulate the flow therethrough and operating means for connecting said valve to the air valve whereby it is operated by said air valve.

6. A charge forming device for internal combustion engines comprising, a primary mixture passage, a secondary mixing chamber into which said passage is adapted to deliver a primary mixture of fuel and air, a primary throttle controlling the flow through said mixture passage, a primary mixing chamber adapted to deliver a mixture of fuel and air to said primary mixture passage, a fuel inlet therefon'an air chamber for supplying air to both of said mixin chambers, a valve controlling admission of air to said air chamb r, a valve controlling communication between the primary mixing chamber and the primary mixture passage, and means for operating said valve in accordance with the movement of the air valve.

7. A charge forming device for internal combustion engines comprising, a primary mixture passage, a secondary mixing chamber into which said passage is adapted to deliver a primary mixture of fuel and air, a primary throttle controlling the flow through said mixture passage, a primary mixing chamber adapted to deliver a mixture of fuel and air to said primary mixture passage, a fuel inlet therefor, an air chamber for supplying air to both of said mixing chambers, a valve controlling admission of to said air chamber, a valve controlling communica tion between the primary mixing chamber and the primary mixture passage, and means for operating said last mentioned valve in accordance with variations in thesuction in the said air chamber.

8. A charge forming device for internal combustion engines comprising, a primary mixture passage, a secondary mixing chamber into which said passage is adapted to deliver a primary mixture of fuel and air, a primary throttle controlling the flow through said mixture passage, a primary mixing chamber adapted to deliver a mixture of fuel and air to said primary mixture passage, a fuel inlet therefor, an air chamber for supplying air to both of said mixing chambers, a valve controlling admission of air to said air chamber, a valve controlling communication between the primary mixing chamber and the primary mixture passage, and means connecting said valves whereby said last mentioned valve is operated by said air valve.

9. A charge forming device for internal combustion engines comprising, a plurality of primary mixture passages, a plurality of secondary mixing chambers into which said primary mixture passages deliver a primary mixture of air and fuel, a throttle controlling the flow through all of said primary mixture passages, a plurality of primary mixing chambers adapted to deliver a primary mixture of fuel and air to said primary mixture passages, fuel inlets for said primary mixing chambers, an air chamber for supplying air to all of said primary and secondary mixing chambers, a single valve controlling communication between all of said primary mixing chambers and said primary mixture passages to control the velocity of flow past the fuel inlets, and means for operating said valve in accordance with the variations in suction in said air chamber.

10. A charge forming device for internal combustion engines comprising, a plurality of primary mixture passages, a plurality of secondary mixing chambers into which said primary mixture passages deliver a primary mixture of air and fuel, a throttle controlling the flow through all of said primary mixture passages, a plurality of primary mixing chambers adapted to deliver a primary mixture of fuel and airto said primary mixture passages, fuel inlets for said primary mixing chambers, an air chamber for supplying air to all of said primary and secondary mixing chambers, a single valve controlling communication between all of said primary mixing chambers and said primary mixture passages to control the velocity of flow past the fuel inlets, a single suction operated air valve controlling the admission of air to said air chambers and means connecting said valves whereby-the air valve is adapted to operate the valve controlling communication between the primary mixing chambers and mixture passages.

In testimony whereof I hereto affix my signature.

FRED E. ASELTINE.

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