US1943909A - Charge forming device - Google Patents

Description

Jan. 16, 1934. F. E. ASELTINE CHARGE FORMING DEVIC E Filed Feb.

2 Sheets-Sheet l 3mm E12 1? 5 14759117175 Jan. 16, 1934. F. E. ASELTINE CHARGE FORMING DEVICE Filed Feb. 1, 1930 2 Sheets-Sheet 2 Patented Jan. 16, 1934 1 943 Hui fl fr- ,7; tliti ihii 1,943,909

CHARGE F-SRMRNG DEVICE Fred Aseltine, Dayton, Ohio, assignor to Del'co:

Products Corporation, Dayton, Ohio, at corporation of Delaware Application February 1, 1930. Serial No. 425,221

21 Claims. (Cl. Zil34) This invention relates to charge forming devices ports of a multicylinder engine. The outlet for internal combustion engines, and more parbranches are each provided with an attaching ticularly to devices of this character which comflange is for securing the manifold to the engine prise a plurality of primary carburetors, which block in the usual manner, and a flange 18' to deliver a primary mixture of fuel and air to a which the carburetor unit is secured. 30

plurality of secondary mixing chambers located The carburetor unit comprises a main housing adjacent the engine intake ports and in which 20, having an attaching flange 22, adapted to be the primary mixture is mixed with additional secured to the flange 18 by screws 24. An air air under certain operating conditions. inlet coupling 28 is secured in position to register A device of this character is described in the with an opening in the upper wall of the hous- 5 copending application of Fred E. Aseltine, Wilinc 0, 111 a y Suitable y- A Casting in ford H. Teeter, and Carl Kindl, Serial No. which the passages supplying fuel to the nozzles 288,683, filed June 2'7, 1928. are formed, is secured to the lower wall of hous- It is the principal object of the present invenin and a S e t eta uel bOWl 32 is held tion to provide improved means for enriching tight against an annular shoulder 34 on the 70 the mixture during the acceleration period. "With hous y any Suitable ea s- Fuel is conthis object in View, one feature of the invention ducted from a main source of supp y to the uel resides in the provision of means to supply addibowl throu a conduit (not shown) and the tional fuel to the mixture passage during the ac- W Of fuel to e bOWl is controlled y a float 20 celeration period following an opening movement Operating n the usual manner maintain a Z5 of t th tt t gfleci iygngsg f hi h i i substantially constant level of fuel therein. creased after the throttle has made a prede- F1161 flows from the bowl 32 to a plurality 0 t mined opening mo ement, primary fuel nozzles 38, one of which is located A further feature of the invention consists in in a of he primary mixing Chambers the 25 the provision of an open well, which is adapted o st uct on o w c is briefly described hereinto be filled with fuel on any opening movement after. The fuel conduit between the fuel bowl of the throttle and from which fuel is adapted to nd he nozzle comprises the v I f p a e be drawn by engine suction and delivered to the 42 communicating at its pper end with the horsecondary air passage. izontal fuel canal 44, which connects with each 30 Another feature of the invention is the proviof the nozzles 38 through an orifice 46. Fuel is sion of an enriching device which is effective to admitted from the fuel bowl to the passage 42 at enrich the mixture to a greater extent and over all engine speeds, through a fixed metering oria longer period of time following an opening of fice 48 and at high speeds additional fuel is adthe throttle when it is opened relatively slowly I initted through an orifice 5O controlled by a valve 35 than on rapid opening movements thereof. 52, operated in the manner set forth in the above Further objects and advantages of the present mentioned application and forming no part of invention will be apparent from the following dethe present invention. scription, r :erence being had to the accompany- Fuel is caused to flow from the fuel nozzles 38 ing drawings wherein a preferred embodiment of to the primary mixing chambers by the suction 40 one form of the present invention is clearly therein. A check valve 5a is provided in an enshown. I larged chamber 56 at the junction of the channels In the drawings: 42 and a4, and on reduction of mixing chamber 1 is avertical, longitudinal section through suction following a. closing movement of the a charge forming device constructed in accordthrottle seats on the bottom of the chamber, pre- 45 ance with the present invention and the intake venting downward flow of fuel.

port with which it is associated. Each primary fuel nozzle is provided with a Figs. 2 and 3 are fragm ntary, detail sections main fuel outlet 58 in the top of the nozzle and a on the lines and 3-3 of Fig. 1. secondary fuel outlet comprising two orifices 60 I Fig. 4 is an elevation partly in section. and 62 in the vertical wall of the nozzle near the 0' Fig. 5 is a side elevation of the device showing bottom of the mixing chamber. At relatively the operating mechanism for the throttle valves. speeds, the mixing chamber suction is suf- The device disclosed comprises a main air manificient to lift fuel from the main outlet as well as fold 10, having three outlet branches, the middle from orifices 60 and 62. At idling, or low speed branch 12 being shown herein. Each of these operation under load, however, the suction is 55' branches communicates with one of the intake enough to lift fuel only to some point between the top of the nozzle and the orifices and 62, fuel flowing from these orifices by the action of gravity under such operating conditions. Each nozzle is provided with a restricted fuel metering orifice 63.

The primary mixing chambers comprise the enlarged anterior ends of the primary mixture passages 64', which are parallel to each other and close together, as indicated in Fig. 2. When the carburetor is attached to the manifold, these passages register with conduits which convey the primary mixture to the secondary mixing chambers, as fully disclosed in the application above referred to, a tube 65 fixed in the middle outlet branch of the manifold constituting the conduit supplying the secondary mixing chamber associated with that particular branch. Restrictions 66 separate the primary mixing chambers from the remainder of the mixture passages to reduce the velocity of fiow past the fuel nozzles for the purpose fully set forth in the above mentioned copending application.

A single throttle valve 68, which extends across all the primary mixture passages, controls the flow therethrough and is provided with grooves 70, which register with said mixture passages. This throttle is operated in a manner hereinafter more fully described. The throttle also controls a plurality of passages '71 which extend from the Y air chamber to the primary mixture passages.

These passages admit additional air in advance of the fuel nozzles, and the amount of air thus admitted is gradually reduced as the throttle is opened, the function of these passages being fully explained in the earlier application above referred to.

Air is admitted to the carburetor through the inlet coupling 28 and is controlled by the main air valve 74, normally held against a seat 76 by a spring Z8, received between the valve and a fiange 80, projecting from a sleeve 82, slidably mounted on a sleeve 84, fixed in the housing 20, and guiding the stem 86 to which the air valve is secured. When the carburetor is choked to facilitate starting, the flange 80 is lifted by means not shown herein, but fully described in the above application, until the upper end of the sleeve 82 engages the air valve to hold it closed. Sufficient air to carry the starting fuel from the nozzles to the intake ports is admitted through an elongated slot 87, formed in a plate 88, secured to the housing 20, as shown in Fig. 1.

The valve 74 admits air to the air chamber 90, from which air flows to the primary passage through an orifice 92 in the bottom of the air chamber and to the secondary mixing chambers through a passage 94, which connects with the inlet of the manifold 10, the how through this passage being controlled by a manually operable valve 96, and by a suction operated valve 100,

secured to shafts 98 and 102 respectively which are journalled in the main housing.

The operating connections for the throttle 68 and the valve 96 include an operating arm 101, which is secured in any suitable manner to a spindle 103 projecting from the end of the throttle valve 68 and extending outside the main housing 20. The operating arm 101 is provided at its free end with an orifice 105 in which any suitable form of operating connection which is adapted to extend to a point convenient to the operator of the vehicle, may be secured. Secured to one end of the shaft 93 on which the valve 96 is mounted, is an operating arm 10'? secured to the shaft by a set screw 109. This operating arm is adapted to be operated from the arm 101 as the primary throttle is opened through the medium of a lost motion connection comprising an operating link 111 pivotally secured by the screw 113 to the arm 101 and provided with a slot 115 therein through which extends a screw 11'? screwed into the arm 107. The screw is connected by a spring 11 to a lug 121 formed by bending over the upper end of the link 111 and is adapted to hold the screw 11'? in the upper end of the slot 115 under certain conditions. Threaded in lugs 123, projecting from the link 111 is an ad- 'dsting screw 125 which may be adjusted to limit the upward movement of the link 111 relative to the arm 107, acting as a stop to prevent further movemen of the link when the screw 125 engages the screw 11'. and the valve 96 is in closed position. In normal position of the parts when the engine is not running and the primary throttie is closed, the screw 11'? is in the lower part of the slot 115 and engaging the screw 125 so that when the arm 101 is moved in a counter clockwise direction to open the primary throttle some movement of the link 111 is permitted without corresponding movement of the arm 107 until the link has moved to such position relative to the arm that the screw 117 engages the upper end of the slot 115. As has been pointed out before, the amount of this movement may be adjusted by adjustment of the screw 125 and the adjustment is generally such that the primary throttle can be opened to a position corresponding to a vehicular speed of substantially 15 to 20 miles per hour before any movement of the arm 10'? and the valve 96 can take place.

On any increase of suction in the main air chamber, the air valve 74 is opened to admit additional air and its opening must be retarded to prevent fluttering thereof and to restrict the admission of air sufiiciently to enrich the mixture to some extent. This is accomplished by a dashpot comprising a cylinder 104, which receives fuel from the main fuel reservoir and a piston 106, secured to the lower end of the valve stem 86 by any suitable means, but the dashpot may be of any I conventional form since its specific construction is not material to the present invention.

As above stated, it has been found necessary to provide a dashpot to retard the opening of the valve 109 whenever the valve 96 is opened, the purpose of this dashpot and its construction being fully described in the above application. The construction of this dashpot is in no way material to the present invention and it is not illustrated herein for the purpose of simplifying the disclosure.

In addition to retarding the opening of the main air valve for the purpose of enriching the mixture during the acceleration period, a pump is provided, which, according to the present invention, is so constructed as to deliver fuel to the secondary air passage 94 immediately anterior to the valve 96 and, therefore, is less eifective before said valve 96 starts to open than after its opening movement begins. This form of pump is provided according to this invention for the reason that prior to the opening of the valve 96 it has been found that the suction at the fuel nozzles increases more rapidly on opening of the throttle than it does after the valve 96 is partly open and is, therefore, effective to supply a mixture of more nearly the desired proportions under these conditions, while the velocity through the primary tubes under such conditions is sufiicient to supply the enriched mixture to the engine cylinders rapidly enough to effect relatively smooth and rapid acceleration of the engine. In most earlier devices of this character, the pump has been designed. to supply fuel to the primary mixture passages and is substantially as effective on opening movements of the primary throttle prior to the opening of the valve 96 as it is subsequent to the opening of such valve. It has been found unnecessary to supply as much additional fuel during a given time interval following an opening movement of the throttle prior to the opening of the valve 96, but because the acceleration is slower than when the opening of the throttle occurs after the opening of valve 96. Because of the slower speed, the period of acceleration is longer, however, and it is desirable to supply the additionalfuelforalongertime. This is accomplished by the arrangement of pump above referred to which delivers to the secondary air passage. According to this invention a pump has been provided which comprises a cylinder 110 formed in the casting 30 and a piston 112 slidable therein. The latter is pivotally secured to an operating rod 116 which extends upwardly through the top of the fuel reservoir and at its upper end is pivotally connected by a pin and slot connection to an operating arm 118 pivotally mounted on a pin 120 screwed into the main housing. A roller 122 is pivotally mounted on the other end of the arm 118 and is engaged by a earn 124 fixed on a spindle 126 projecting from the end of the primary throttle. The pump piston is moved downwardly by the cam on every opening movement of the primary throttle to force fuel through a fuel delivery passage 128 connected with the cylinder 110 near its bottom and having an enlargement 130 at its upper end at which a check valve 132 is received to prevent return of the fuel to the pump cylinder on closing movement of the air valve. The passage 128 communicates above the check valve with a horizontal passage 134 leading to a well 136, formed in the casting 30 and communicating with the atmosphere through an orifice 138, so that atmospheric pressure is maintained within the well. A delivery tube 140 is received in a bore in the main housing and extends into the well 136, terminating adjacent the bottom thereof, while the upper end of this delivery tube is provided with a restriction 142 to limit the rate of flow of fuel from said well and to effect atomization of the fuel delivered. On every operation of the pump piston, surplus fuel above the capacity of the well is discharged through the orifice 138 into the main fuel reservoir, the suction of the manifold is communicated to the upper end of the delivery tube 140 and the fuel retained in the well is drawn out of such well into the secondary air passage 94 until the level of fuel in the well falls below the lower end of the tube.

It will be clear that a greater amount of fuel is drawn into the air passage 94 when the throttle is opened relatively slowly and that such fuel is supplied to said air passage through a greater period of time than when the throttle is opened relatively rapidly. On relatively slow opening movements of the throttle, the fuel is supplied to the well relatively slowly and such fuel is mostly drawn into the air passage 94 with but little overflowing from the well and returning to the main fuel reservoir through the orifice 138. Also when the throttle is opened relatively slow- 1y fuel will be supplied to the well by the pump and drawn therefrom through the tube 140 for a greater length of time than when the throttle is opened rapidly, for when this occurs, the fuel is supplied to the well by the pump very rapidly and a larger proportion of it is returned to the main fuel reservoir through the orifice 138; while the relatively small amount of fuel that does not so overflow is drawn into the air passage 94 much more rapidly than when the throttle is opened slowly.

The secondary mixing chambers may be of any desired construction which will accelerate the flow of air past the ends of the primary mixture conduits and as illustrated, each secondary mixing chamber comprises a Venturi tube 122, positioned adjacent the outlet end of the primary mixture conduit. Each Venturi is provided with an exterior rib 144, adapted to be clamped between shoulders on the manifold and engine blocks respectively, when the device is assembled.

The Venturi tubes serve to accelerate the flow through the primary mixture conduits in the manner fully disclosed in the earlier application. The advantageous results produced by the fuel pump disclosed above, will be obvious from the description of the operation of said pump and need not be repeated.

In the event of an excess accumulation of fuel in the secondary air passage before the valve 96 opened, as might occur in the event that the throttle were opened and closed several times to a moderate extent but not enough to cause opening of the valve 96, some of the accumulated fuel might pass through the holes 71 into the primary mixing chambers.

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.

What is claimed is as follows:

1. A charge forming device for internal combustion engines comprising, a mixture passage having a mixing chamber therein, means for supplying fuel and air to the mixture passage, a secondary air passage adapted to supply additional air to said mixing chamber at a point remote from the mixing chamber under certain operating conditions, a throttle, and means operated by the throttle on opening movements thereof under any operating conditions for supplying fuel to the secondary air passage.

2. A charge forming device for internal combustion engines comprising, a mixture passage having a mixing chamber therein, means for supplying fuel and air to the mixing chamber, a secondary air passage adapted to supply additional air to said mixture passage at a point remote from the mixing chamber, a throttle, and a fuel pump operated by the throttle on opening movements thereof for supplying fuel to the secondary air passage.

3. A charge forming device for internal combustion engines comprising, a mixture passage, means for supplying fuel and air to the mixture passage, a secondary air passage adapted to supply additional air to said mixture passage, a

throttle, a valve in the secondary air passage operated by said throttle for controlling the flow therethrough and means also operated by the throttle on opening movements thereof for supplying fuel to said secondary air passage.

4. A charge forming device for internal combustion engines comprising, a mixture passage, means for supplying fuel and air to the mixture passage, a secondary air passage adapted to supply additional air to said mixture passage, a throttle, a valve in the secondary air passage operated by said throttle for controlling the flow therethrough and means also operated by the throttle on opening movements thereof for supplying fuel to said secondary air passage adjacent the valve therein.

5. A charge forming device for internal combustion engines comprising, a mixture passage, means for supplying fuel and air to the mixture passage, a secondary air passage adapted to supply additional air to said mixture passage, a throttle, a valve in the secondary air passage operated by said throttle for controlling the flow therethrough and means also operated by the throttle on opening movements thereof for supplying fuel to said secondary air passage anterior to the valve therein.

6. A charge forming device for internal combustion engines comprising, a mixture passage having a mixing chamber therein, means for supplying fuel and air to the mixing chamber, a secondary air passage adapted to supply additional air to said mixture passage, a throttle, a valve in said secondary air passage adapted to be opened after the throttle has made a predetermined opening movement, and means operated by the throttle on opening movements thereof for supplying fuel to said secondary air passage at a point remote from the mixing chamber both before and after the opening of said valve.

7. A charge forming device for internal combustion engines comprising, a mixture passage, means for supplying fuel and air to the mixture passage, a secondary air passage adapted to supply additional air to said mixture passage, a throttle, a valve in said secondary air passage, means operated by the throttle for opening said valve after the throttle has made a predetermined opening movement, and means operated by the throttle on opening movements thereof for supplying fuel to said secondary air passage both before and after opening of said valve.

8. A charge forming device for internal combustion engines comprising, a mixture passage, means for supplying fuel and air to the mixture passage, a secondary air passage adapted to supply additional air to said mixture passage, a throttle. a valve in said secondary air passage adapted to be opened after a predetermined opening movement of the throttle, means operated by the throttle on opening movements thereof for supplying fuel to said secondary air passage both before and after the opening of said valve, and a passage connecting the secondary air passage with the mixture passage, whereby some of the fuel supplied to the secondary air passage may iiow into the primary mixture passage before the opening of said valve.

9. A charge forming device for internal combustion engines comprising a mixture passage having a mixing chamber formed therein, means for supplying fuel and air to said mixing chamber, a throttle, a secondary air passage adapted to admit additional air to the mixture passage at a point remote from the mixing chamber, and means operated by the throttle for supplying fuel to said secondary air passage at a point relatively close to the intake end of the secondary air passage, during the acceleration period.

10. A charge forming device for internal combustion engines comprising a mixture passage having a mixing chamber formed therein, means for supplying fuel and air to said mixing chamb r, a throttle, a secondary air passage adapted to admit additional air to the mixture passage at a point remote from the mixing chamber, a valve in said secondary air passage, and means operated by the throttle for supplying fuel to said secondary air passage at a point anterior to said valve.

11. A charge forming device for internal combustion engines comprising a mixture passage having a mixing chamber formed therein, means for supplying fuel and air to said mixing chamber, a throttle, a secondary air passage adapted to admit additional air to the mixture passage, a valve in said secondary air passage adapted to be opened during certain opening movements of the throttle only, and means operated by the throttle on all opening movements thereof for supplying fuel to said secondary air passage anterior to said valve, whereby on opening movements of the throttle when the valve remains closed, fuel is accumulated in the secondary air passage to enrich the mixture whenever said valve begins to open.

12. A charge forming device for internal combustion engines comprising a mixture passage having a mixing chamber formed therein, means for supplying fuel and air to said mixing chamber, a throttle, a secondary air passage adapted to admit additional air to the mixture passage, a val in said secondary air passage adapted to be or led only after the throttle has made a predetermined movement, a fuel pump operated by the throttle, and a fuel delivery conduit extending from said pump to the secondary air passage at a point anterior to said valve, whereby when the valve is closed fuel is supplied to said air passage by the action of the pump alone, but when the valve is open said fuel delivery conduit is subject to the action of engine suction.

13. A charge forming device for internal combustion engines comprising a mixture passage having a mixing chamber formed therein, means for supplying fuel and air to said mixing chamher, a throttle, a secondary air passage adapted to admit additional air to the mixture passage, a valve in said secondary air passage adapted to be opened only after the throttle has made a predetermined movement, a fuel pump operated by the throttle, a reservoir supplied with fuel by said pump, a delivery tube extending from the reservoir into said secondary air passage at a point anterior to the valve, whereby engine suction communicated to said delivery tube is increased when the valve is opened.

l l. A charge forming device for internal combustion engines comprising a secondary mixing chamber, a primary mixture passage adapted to deliver a primary mixture of fuel and air to said secondary mixing chamber, means for supplying fuel and air to said primary mixture passage, a primary throttle in said passage controlling the flow therethrough, a secondary air passage adapted to supply air to the secondary mixing chamber and means operated by the primary throttle for supplying fuel to the secondary air passage during the acceleration period.

15. A charge forming device for internal combustion engines comprising a secondary mixing chamber, a primary mixture passage adapted to deliver a primary mixture of fuel and air to said secondary mixing chamber, means for supplying fuel and air to said primary mixture passage, a primary throttle in said passage controlling the how therethrough, a secondary air passage adapted to supply air to the secondary mixing chamber and means operated by the primary throttle on all opening movements thereof for supplying fuel to the secondary air passage during the acceleration period.

16. A charge forming device for internal combustion engines comprising a secondary mixing chamber, a primary mixture passage adapted to deliver a primary mixture of fuel and air to said secondary mixing chamber, means for supplying fuel and air to said primary mixture passage, a primary throttle in said passage controlling the flow therethrough, a secondary air passage adapted to supply air to the secondary mixing chamber, a valve in said secondary air passage and means operated by the primary throttle for supplying fuel to said secondary air passage at a point anterior to the valve therein.

17. A charge forming device for internal combustion engines comprising a secondary mixing chamber, a primary mixture passage adapted to deliver a primary mixture of fuel and air to said secondary mixing chamber, means for supplying fuel and air to said primary mixture passage, a primary throttle in said passage controlling the flow therethrough, a secondary air passage adapted to supply air to the secondary mixing chamber, a valve in said secondary air passage adapted to be opened during a part of the opening movement of the primary throttle and means operated by the primary throttle for supplying fuel to the secondary air passage during the entire opening movement thereof.

18. A charge forming device for internal combustion engines comprising a secondary mixing chamber, a primary mixture passage adapted to deliver a primary mixture of fuel and air to said secondary mixing chamber, means for supplying fuel and air to said primary mixture passage, a primary throttle in said passage controlling the flow therethrough, a secondary air passage adapted to supply air to the secondary mixing chamber, a valve in said secondary air passage adapted to be opened during a part of the opening movement of the primary throttle and means operated by the primary throttle during its entire opening movement for supplying fuel to the secondary air passage anterior to the valve therein, whereby fuel is accumulated in said air passage prior to the opening of said valve.

19. A charge forming device for internal combustion engines comprising a secondary mixing chamber, a primary mixture passage adapted to deliver a primary mixture of fuel and air to said secondary mixing chamber, means for supplying fuel and air to said primary mixture passage, a primary throttle in said passage controlling the flow therethrough, a secondary air passage adapted to supply air to the secondary mixing chamber, means subject to the engine suction and normally ineffective for supplying fuel to the secondary air passage during the acceleration period and means operated by the primary throttle for rendering said last named means eifective.

20. A charge forming device for internal combustion engines comprising a secondary mixing chamber, a primary mixture passage adapted to deliver a primary mixture of fuel and air to said secondary mixing chamber, means for supplying fuel and air to said primary mixture passage, a primary throttle in said passage controlling the flow therethrough, a secondary air 100 passage adapted to supply air to the secondary mixing chamber and means controlled jointly by the engine suction and the primary throttle for supplying fuel to the secondary air passage during the acceleration period.

21. A charge forming device for internal combustion engines comprising a plurality of primary mixture passages adapted to supply a primary mixture of fuel and air to a plurality of secondary mixing chambers, means for supplying 110 fuel and air to said primary mixture passages,

a primary throttle for controlling the flow of mixture through said primary mixture passages,

a single secondary air passage for supplying air to all of said secondary mixing chambers and 115 means operated by the primary throttle for supplying fuel to said secondary air passage during the acceleration period.

FRED E. ASELTINE.

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