US1854172A - Charge forming device - Google Patents

Description

19, 1932. ANSQN CHARGE FORMING DEVICE 4 Sheets-Sheet Filed Oct. 3, 1928 April 19, 1932- J. 1. ANSON CHARGE FORMING DEVICE Filed Oct. 3, 1928 4'Sheets-Sheet 2 fnuEnTar 4HMM 1 M April 19, 1932. J. l. ANSON 1,354,172

CHARGE FORMING DEVICE Filed Oct. :5 1928 4 Sheets-Sheet s p 1 511, 111111!!! Iy IIIIIIIIIIIIJ April 19, 1932. J, ANSQN 1,854,172

CHARGE FORMING DEVICE Filed Oct. 3, 1928 4 Sheets-Sheet 4 atente Apr. 1, l3

JEROME I. ANSON, 0F DAYTON, OHIO, ASSIGNOR, BY MESNE ASSIGNMENTS, TO DELCO PRODUCTS CORPORATION, OF DAYTON, OHIO, A CORPORATION OF DELAWARE FORMING DEVICE Application filed October 3, 1928. Serial No. 310,044.

- This invention relates to charge forming devices for internal combustion engines and more particularly to the type of charge forming device which comprises a plurality of primary fuel mixing chambers, one for each intake port of the engine and cooperating respectively with a plurality of secondary fuel mixing chambers located adjacent the engine intake ports, and receiving fuel air mixture from pipes connectedwith the primary carburetors, and receiving air, when required, through branches of an air manifold having a single air inlet for supplying air to all the secondary mixing chambers, the quantity of mixture-flowing through the secondary carburetors being controlled primarily by a single main air throttle. A common fuel reservoir supplies liquid fuel to all of said primary carburetors.

Examples of charge forming devices of this character are disclosed in the copending applications of Wilford H. Teeter, Serial No. 221,372, filed September 22, 1927, and Fred E. Aseltine and Wilford H. Teeter,

' Serial N 0. 221,371, filed September 22, 1927,

which matured to Patent 1,819,495 granted Aug. 18, 1931. In earlier designs of charge forming devices of this character, such as those shown in the above applications, the velocity of the air passing the jets increases so rapidly as the engine speed increases that a velocity head is built up at the jets which is efi'ective to cause suflicient flow of fuel therefrom to form too rich afuel mixture unless some compensating means is provided. It has been the practice to provide a secondary air passage controlled by a manually operable throttle valve which is adapted to be opened at a predetermined engine speed to compensate for the action of the velocity head above referred to. It has been found diificult, however,to provide a valve for this purpose which may be opened sufliciently to admit the requisite amount of air to secure the desired volumetric efficiency of the engine without admitting air too rapidly to compensate for the effect of velocity head on the fuel flow resulting in the formation of too lean a mixture after the air valve is opened. -In fact, since the velocity head is a variable thing which depends on several different factors, it has been found diificult to control the admission of air in the proper proportions by means of the air throttle to form a mixture of desired proportions for all speeds, even if the valve is effective to produce a mixture of proper proportions at some particular speed.

It is, therefore, the principal object of the present invention to provide improved means for controlling the proportions of fuel and air in the mixture, which is efl'ective to provide a mixture of the desired proportions at all engine speeds and under all operating conditions.

It is a more specific object of the present invention to provide means for admitting additional fuel to the mixture passage at speeds above a predetermined speed and to variably control the admission of such fuel.

Another specific object of the invention is to provide an additional fuel jet for admitting fuel to the mixture passage at speeds above a predetermined speed and to control the flow of fuel from said jet by variably admitting air thereto.

The above objects are accomplished according to this invention by the provision of a plurality of high speed fuel jets, each of which is adapted to deliver additional fuel to one of the secondary mixing chambers when the main air throttle is opened. The action of these jets is controlled by the primary throttle which operates an air valve regulatingthe admission of air to said jets, the construction being such that when the main air throttle is closed,'the air valve referred to is open, admitting sufiicient air to prevent the maintenance of sufficient suction at the jets to draw fuel therethrough. The air valve is operated by means of a cam which can be made of any desired contour to regulate the position of said air valve in' any desired manner to variably restrict the flow of air through said jets and in that way regulate the flow of liquid therefrom to proportion the mixture in such manner as to most satisfactorily operate the engine under all operating conditions. 7

Further objects and advantages of the resent invention will be apparent from the ollowing description, reference being had to theaccompanying 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 the present invention attached to the engine cylinder head,

' a part of which is shown in section.

Fig. 2 is a side elevation looking toward the engine block.

Fig. 3 is a section on the line 33 of Fig. 1. Fig. 4 is a section on the line 44 of Fig. 3. Fig. 5 is a fragmentary detail view on the line 55 of Fig. 3.v

Fig. 6 is a side elevation of the main carburetor unit viewed from the right in Fig. 2.

Fig. 7 is a side elevation of the main carburetor unit viewed from the left of Fig. 2. Fig. 8 is a detail section on' the line 88 of Fig. 3. I Fig. 9 is a section through the secondary mixing chamber on the line 9-9 of Fig. 2.

Figs. 10 and 11 are detail sections at right angles to each other of the float valve mechanism and the fuel inlet controlled thereby.

Fig. 12 is a detail view of the fuel pump. The device disclosed herein comprises a main air manifold indicated in its entirety by the reference character 10 and having three outlet branches 11, 12, and 13, each of which is adapted to communicate with one of the ports 14 of a multicylinder engine. Each port serves two adjacent cylinders through valve ports 14a and 14?), as clearly indicated in Fig. 1. The cylinder head is shown in three separate fragments 15, but it will be understood that it may be an integral structure. The branches 11, 12, and 13 are each provided with a stationary flange 16 for attaching the manifold to the engine block in the usual manner and adjacent the inlet of the manifold is provided a flange 17 to which may be secured the main carburetor unit, as illustrated in Figs. 1 and 3.

The main carburetor unit comprises a main housing 18, pro *ided with a flan e 19, adapted to be secured by screws 20, to the flange 17. An air inlet horn 21 is secured in position to register with an opening in the upper wall of the housing 18 in any suitable way. A casting 22 in which the main fuel passage is formed, is secured by screws to the lower wall of the housing 18 and a sheet metal fuel bowl 23 is held tight against an annular shoulder 24, formed on the skirt 25, depending from the main housing 18, by means of a screw 26 screwed into a post 27, projecting downwardly from the casting 22. Fuel is conducted from the main source of supply to the fuel bowl through a conduit, not illustrated herein, which connects with a nipple 28. The nipple communicates with an angular fuel passage 29 formed in the main housing, which in turn connects with a passage 30 in the casting 22. A. plug 31 is screwed into the lower end of the passage 30 and is provided with a restriction 32, forming a valve seat with which a valve 33 cooperates, and when open, permits a flow of fuel through the lateral fuel ports 34. The valve 33 is controlled by a float 35 pivoted at 36, as shown in Fig. 10 and operating in the usual manner to maintain a constant fuel level in the fuel bowl.

Fuel is conducted from the fuel bowl to a plurality of primary fuel nozzles 37 located in the primary mixing chambers 38, formed in the central part of the main housing 18, and more fully described hereinafter. To convey fuel from the fuel bowl to the above mentioned fuel nozzle, a vertical fuel conduit 39 is provided in the casting 22 and connects at its upper end with a horizontal fuel canal 40, which communicates with the fuel nozzles 37 through orifices 41. Fuel is lifted from the bowl through the nozzles 37 to the primary mixing chambers by the suction maintained therein, and when the throttle is moved toward closed position to reduce the engine speed, there is a sudden reduction in the suction effective on the column of fuel between the fuel bowl and the nozzle outlets, which might permit this column of fuel to drop sufficiently to cause a temporary fuel starving of the engine unless means were provided to prevent such action. Such means comprises a check valve 42, received in the enlar ed chamber 43 located at the junction of uel passages 39 and 40, and which is normally lifted by suction, but on reduction of suction in the primary mixing chambers, rests on an annular rib 44 proJecting upwardly from the bottom of said enlarged chamber, thus preventing downward flow of fuel through the fuel passage 39.

Each primary fuel nozzle is provided with amain fuel outlet in the top of the nozzle and a separate secondary fuel outlet comprising two holes 46 and.47 formed in the vertical wall of the nozzle near the bottom of the primary mixing chamber and diametrically opposite each other, as shown in Fig. 3. At higher engine speeds there is sufficient suction in the primary mixing chambers to lift fuel from the main outlets in the top of the nozzles as well as from the orifices 46 and 47. During idling or low speed operation under load, however, there is insufficient suction to cause such a flow of fuel, the fuel under such operating conditions standing in the nozzles at a point between the top of the nozzle and the orifices 46 and 47, and flowing from such orifices by the action of gravity. Each of the fuel nozzles is provided with a restricted metering The primary mixing chambers hereinbefore referred to, form part of three primary mixture passages indicated in their entirety by the reference number 50. These passages are parallel to each other and are close together, the mixing chambers being in axial alignment with the balance of the passages as illustrated in Figs. 3, 4, and 5. All of these passages are adapted to communicate with primary mixture conduits which convey the primary mixture to the secondary mixing chambers formed in the outlet branches 11, 12, and 13 of the manifold, and

which will now be described. Pipes 51 connect the two outer primary mixture passages with the branches 11 and 13 of the manifold, as indicated in Fig. 1, and as fully described in copending application Serial No. 288,683, filed June 27, 1928. The two pipes 51 are connected with elbows 52, which communicate with tubes 53 and 54, which are received in the outlet branches 11 and 13 respectively of the manifold, and terminate within the secondary mixing chambers, hereinafter more fully described. The middle one of the primary mixture passages 50, however, communicates directly with a tube 55 similar in construction to the tubes 53 and 54, and received in the middle branch 12 of the manifold, as illustrated in Fig. 3. The inlet ends of the primary mixture passages which form primary mixing chambers 38 are of larger diameter than the outlet ends of such passages and between the inlet and outlet ends of such passages the cross sectional area is restricted as indicated at 56 in Fig. 3, this restriction acting to reduce the velocity of the air current passing the nozzle to some extent.

The flow of primary mixture through the mixture passage 50 is controlled by a single primary throttle Valve 60, which extends across all of said'passages and is provided with grooves 61, which register therewith. This throttle valve has spindles 62 and 63 projecting from opposite ends thereof outside of the casing which serve as supports for certain operating connections and said throttle valve is rotatably mounted in the housing 18. A screw 64 is adapted to engage a groove in the throttle to prevent longitudinal movement thereof. The primary mixture flows through the above mentioned passages and mixture delivery conduits to the secondary mixing chambers in such volume as determined by the primary throttle and is adapted under certain operating conditions to be mixed with additional air in said secondary mixing chambers, as hereinafter more fully described.

Substantially all the air entering the carburetor flows through the air horn 21, the flow therethrough being controlled by a main air valve 65 normally held against the seat 66 by a spring 67, received between the valve and a flange 68, projecting from a sleeve 69,

which is slidably' mounted on .a stationary 1 guide sleeve 70, fixed in the housing 18, and

seat by means of arm 7 5, secured to a rock shaft 76, rotatably mounted in the wall of the housing 18. The arm, at its inner end, is provided with two pins 77 and 78 between which the projecting flange 68 on the slidable sleeve 69 is received. The shaft 76 projects through the wall of the housing and at its outlet endis bent to form an operating arm 79 having a hole 80 therein in which some form of operating connection, extending to a point convenient to the operator of the ve hicle, may be attached. An adjustable stop screw 81 is threaded in a lug 82' de'tachably secured to the air horn as indicated in Fig. 2. Adjustment of the screw 81 determines the normal position of the sleeve 69 and the tension of the spring 67. Ordinarily the screw 81 is so adjusted that the main air valve will open slightly during idling. To provide sufiicient air to carry the starting fuel from the fuel nozzle 37 to the engine when the carburetor is choked, an air inlet 83 in the form of an elongated slot in a plate 84 secured to the housing 18, is provided.

Flow of air from the air chamber 7 2 to the secondary mixing chambers is controlled by a manually operable throttle 90, secured to a shaft 91, rotatably mounted in the housing 18. This throttle is adapted to be operated concurrently with the primary throttle 60 by means of a lost motion linkage, which will now be described. Fixed on the spindle 62, projecting from the primary throttle, is an operating arm 92 adapted to be connected 4 to some form of operating connection extending to a point adjacent the operator of the vehicle. The arm 92 is connected to an arm 93, clamped on the end of shaft 91, by an operating line 94, which is pivotally connected to the arm 92 and is provided with a slot 95 through which a pin 96, projecting from the end of arm 93, extends. A regulating screw 97 is threaded in lugs 98 formed on the link 94 and may be adjusted to regulate the length of the slot 95. A tension spring 99 is connected at one end to the upper end of the link 94 and at its other end to 'the pin 96, said spring tending to hold the pin against the upper end of the slot 95. With both the throttles closed, the parts are in the position shown in Fig. 6, with the pin 96 in engagement with the end of the screw 97.

As the arm 92 is rotated in a counter-clockwise direction to open the primary throttle valve, the link 9 1 is moved downward to a position where the upper end of the slot 95 engages the pin 96 before the operating arm 93 of the air throttle 90 is moved. In this manner, the primary throttle is partly opened before the air throttle begins its opening movement. The screw 97 forms a stop to limit the closing movement of the primary throttle and adjustment of said screw regulates the throttle opening at idling.

On opening of either or both of the throttle valves above referred to, the suction in the air chamber 72 is increased sufficiently to open the air valve against the tension of its spring to admit additional air. The opening of this valve must be retarded to some extent, however, to prevent admission of sufficient air to lean the mixture. A. dash pot is provided to accomplish this result and also to prevent fluttering of the valve, said dash pot comprising a cylinder 100 formed in the casting 22 and a piston 101 secured to the lower end of the air valve stem 71 by means of a nut 102', or in any desirable manner. The specific. construction of this dash pot constitutes no part of the present invention and the dash pot may be of any conventional form.

The above described dash pot may also constitute a fuel pump for supplying additional fuel to the primary mixture passages on opening movements of the throttle valve to provide the enriched mixture necessary to secure proper engine operation during the period of acceleration. To this end an outlet pipe 103 communicates with the dash pot cylinder 100 near the bottom thereof and connects with a valve seat member 104 closed by a check valve 105, held in-closed position by a spring 106, which is received within a fitting 107, at-

tached to the valve seat member. A. fuel delivery pipe 108 is attached to the fitting 107 and extends upwardly to a point above the air valve 65 where the end of the said pipe is bent to extend through an orifice in the wall of the air horn. On opening of the air valve fuel is pumped from the dash pot cylinder through the above described delivery conduit and is deposited on the surface of the air valve. This is substantially the same form of fuel pump as is shown in application Serial No. 221.372, and its specific construction is no part of the present invention; in fact, any conventional form of fuel pump maybe employed in a charge forming device in which the structure comprising the present invention is embodied without affecting the function of or result produced by such structure.

A secondary mixing chamber is associated with each outlet branch of the manifold. There are three of these mixing chambers of identical construction and each comprises a v Venturi tube 110 clamped between the maniesa-ave fold and the engine block and positioned so that the outlet of the primary mixture delivery conduit terminates at the point of greatest suction in the Venturi tube. Each venturi is provided with an externally projecting rib 111 whichis clamped, when the device is assembled with the manifold attached to the block, between shoulders 112 and 113 formed on the manifold and the engine block respectively. These Venturi tubes causethe air passing the ends of the primary mixture delivery conduits to move at high velocity creating in said conduits a relatively high suction under all operating conditions.

The above described structure is all substantially the same as that disclosed in the earlier applications above referred to. As indicated hereinbefore, considerable diificulty has been met in regulating the mixture proportions under various different operating conditions. For instance, with the structure above described, if the jets are calibrated to admit a proper amount of fuel to form a mixture of the desired proportions during operation with the main air throttle 90 closed, such mixture will become too lean after the throttle 90 is opened, and if the jets are designed to supply the proper amount of fuel after the opening of the throttle 90, the mixture will be too rich before such throttle is opened. In order to provide a mixture of proper proportions throughout the entire operating range, the present invention contemplates the provision of a plurality of additional fuel jets, one of which is adapted to supply fuel to each of the secondary mixing chambers, and means for controlling the supply of fuel admitted through the said additional jets in any desired manner to provide a mixture of the desired proportions to most satisfactorily operate the engine under all operating conditions during the entire operating range of the engine.

The means for supplying additional fuel in the secondary mixing chambers comprises a fuel supply tube 115 screwed into the bottom wall of the main housing 18, as indicated in Fig. 8. This tube extends to a point below the fuel level and at its upper end connects with a horizontal fuel channel 116 which in turn communicates with a three-way nipple 117 screwedinto the channel 116 at the outer end of said channel. This nipple is connected with three fuel delivery pipes 118, 119, and 120 supplying fuel to the secondary mixing chambers formed in the manifold branches 11, 12, and 13 respectively. Each of the pipes 118, 119, and 120 projects through the wall of one of the manifold branches and terminates flush with the inner wall of one of the Venturi tubes 110 at substantially the point of greatest suction therein, as shown fully in Fig. 8. To regulate the flow of fuel through the pipes above referred to, air is admitted to the fuel channel 116 by means of a passage 121 bored in the main housing 18 and communicating at one end with the atmosphere and at the other end with a chamber 122, formed in the wall of the housing. This chamber is closed at its upper end by means of a plug 123 and received in the chamber is a valve 124, which is adapted to regulate the admission of air to the passage 116. The valve is provided with a projecting flange 125 and received between said flange and the bottom of chamber 122 is a spring 126,-Which tends at all times to lift the valve and permit a flow of air from said chamber through a passage 127 controlled by the valve, into fuel channel 116. The valve is adapted to be moved downwardly under certain operating conditions by means of a cam 128 adjustably secured to the spindle 62, projecting from one end of the primary throttle.

i The operation of the above described means for supplying additional fuel is substantially as follows. During all operating conditions, when the air throttle is closed, the cam 128 is inefiective to lower the valve 124 and a maximum flow of air is permitted through the passages 121 and127. This flow of air will be sufficient to reduce the suction in the fuel channel 116 to a point below that necessary to lift fuel from the fuel bowl to said channel so that no fuel is admitted to the secondary mixing chambers while the secondary throttle 90 is closed. As the throttle 90 begins to open, the primary throttle has reached a position Where the cam lowers the valve 124 to partially close the passage 127, and as the throttles are moved to fully open position,the valve 124 is moved to fully closed position, so that the flow of air into the channel 116 is first restricted and then entirely prevented. In this manner the suction in said channel 116 is gradually increased until it is suflicient to draw fuel from the fuel bowl into said channel, where the fuel is mixed with air when the valve 124 is partially open and supplied to the secondary mixing chambers in the form of an emulsion of fuel and air. After the valve 124 is entirely closed, a solid column of fuel is drawn through the pipes 118, 119, and into said secondary mixing chambers. By means of this device, the supply of fuel through the secondary jets is increased as the valve 90 is opened to supply additional ainto the mixture so that the mixture maybe maintained substantially uniform throughout the entire operating range. This is the operation of a preferred form of this device, but the cam 128 operated by the primary throttle may be designed in any desired manner so as to regulate the flowof fuel through the secondary fuel jets in whatever quantity is desired to meet any particular operating condition and the invention is in no way lirrited to any particular form of 0am to regulate the supply of fuel in any particular manner.

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, means for supplying air thereto, a plurality of fuel inlets supplying fuel to said mixture passage, means for effecting a relatively rapid increase in fuel fi'ow from one of said inlets on increase of engine speed which is effective throughout engine operation at such increased speed, and means for retarding the normal liquid fuel flow from another of said inlets whereby a relatively slow increase in liquid fuel flow is effected on increase in engine speed.

2. A charge forming device for internal combustion engines comprising a mixture passage, means for supplying air thereto, a main fuel inlet supplying liquid fuel thereto during all engine operating conditions, a secondary fuel inlet supplying fuel thereto only after a predetermined engine speed is reached, and means for effecting a slower increase in liquid fuel flow from the secondary jet on increase in engine speed than from the main jet.

3. A charge forming device for internal combustion engines comprising a mixture passage, means for supplying air thereto, a main fuel inlet supplying liquid fuel thereto during all engine operating conditions, asecondary fuel inlet supplying fuel thereto,

means admitting air to said secondary inlet to prevent flow of liquid fuel from said jet until a predetermined engine speed is reached, and means for decreasing the quantity of air admitted as the engine speed increases.

4. A charge forming device for internal combustion engines comprising a mixture passage, means for supplying air thereto, a main fuel inlet supplying liquid fuel thereto during all engine operating conditions, a secondary fuel inlet supplying fuel thereto, a throttle, and means operated by the throttle for preventing a flow of liquid fuel from said secondary inlet until a predetermined engine speed is reached.

5. A charge forming device for internal combustion engines comprising a mixture passage, means for supplying air thereto, a main fuel inlet supplying liquid fuel thereto during'all engine operating conditions, a secondaryfuel inlet for supplying fuel thereto, a throttle, means operated by said throttle for preventing any flow of liquid fuel from said secondary fuel inlet until a predetermined engine speed is reached and for re ulating the flow of liguid fuel from said inlet after it becomes e fective.

6. A charge forming device for internal combustion engines comprising a mixture passage, means for supplying air thereto, a main fuel inlet supplying liquid fuel thereto during all engine operating conditions, a secondary fuel inlet supplying fuel thereto, a throttle, means for admitting air to said secondary fuel inlet to control the flow of liquid fuel therefrom and means operated by the throttle for regulating the quantity of air admitted as the throttle is opened to increase the engine speed.

7. A charge forming device for internal combustion engines comprising a primary mixture passage, air and fuel inlets therefor, a secondary mixing chamber into which said mixture passage delivers, a secondary fuel inlet, from which fuel is adapted to be drawn into the secondary mixing chamber by the suction therein, and means for variably increasing the rate of fuel flow from the secondary fuel inlet on increase in engine speed.

8. A charge forming device for internal combustion engines comprising a primary mixture passage, an air inlet therefor, a main fuel inlet adapted to deliver liquid fuel to said primary mixture passage, a secondary mixing chamber into which said mixture passage delivers, a secondary fuel inlet adapted to deliver an emulsion of fuel and air to said secondary mixing chamber, and means for variably increasing the rate of fuel flow from the secondary fuel inlet on increase in engine speed.

9. A charge forming device for internal combustion engines comprising a primary mixture passage, air and fuel inlets therefor, a secondary mixing chamber into which said mixture passage delivers, a secondary fuel inlet adapted to deliver fuel to said secondary mixing chamber, primary and secondary throttles and means operated by said primary throttle for controlling the action of said secondary fuel inlet.

10. A charge forming device for internal combustion engines comprising a primary mixture passage, air and fuel inlets therefor, a secondary mixing chamber into which said mixture passage delivers, a primary throttle controlling the flow through said mixture passa e, an air throttle adapted to be opened w en a predetermined engine speed is reached to admit air to said secondary mixing chamber, a secondary fuel inlet adapted to deliver fuel to thesecondary mixing chamber after a predetermined engine speed is reached, means for admitting air to said secondary fuel inlet to regulate the flow therefrom, and means for decreasing the uantity of air admitted to said fuel inlet as t e air throttle is opened to increase the flow of fuel from the secondary fuel inlet as the flow of secondary air is increased.

11. A charge forming device for internal reserve of primary mixture passages, means for supplying fuel and air thereto, a plurality of secondary'mi-xing chambers into which said .primary mixture passages deliver, a single throttle adapted to control the flow through all of said mixture passages, a plurality of secondary fuel inlets adapted to supply fuel to said secondary mixing chambers, a single means for admitting air to all of said second ary fuel inlets to control the flow therefrom, and means operated by the throttle for controlling said air admitting means.

12. A charge forming device for internal combustion engines comprising a mixture passage, means for supplying air thereto, a main fuel inlet effective to supply liquid fuel thereto during all operating conditions, a secondary fuel inlet therefor operable only under certain operating conditions, and meansfor admitting a decreasing quantity of air to said secondary fuel inlet as the engine speed increases.

In testimony whereof 1 hereto afix my signature.

JEROME If. ANSUN.

combustion engines comprising, a plurality

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