US1922407A - Charge forming device - Google Patents

Description

Aug. 15, 1933. w. H. TEETER CHARGE FORMING DEVICE Filed Sept. 7, 1929 (7&6

Jay. 4-

ll/z'lford Ii Jeeier Patented Aug. 15, 1933 CHARGE FORMING DEVICE Wilford Teeter, Dayton, Ohio, assignor to 'Delco Products Corporation, Dayton, Ohio, a Corporation of Delaware Application September 7, 1929. Serial No. 391,057

22 Claims.

This invention relates to charge forming devices for internal combustion engines, and most particularly to that type of charge forming device which comprises a plurality of carburetors, one for each intake port of the engine, which are adapted to deliver a primary mixture of fuel and. air to a plurality of secondary carburetors located adjacent the engine intake ports, where additional air is mixed with the primary mixture before the latter enters the engine cylinders.

A device of this character is disclosed in the copending application of Wilford H. Teeter, Serial No. 288,685, filed June 27, 1928, and the present invention is disclosed herein as embodied in a charge forming device having the structure of that disclosed in said application.

It is theobject of the present invention to provide improved means-for enriching the mixture during the acceleration period, and more particu- 20 larly to provide means which is effective to enrich the mixture during opening movements of the throttle under certain operating conditions when enrichment of the mixtureis desirable, and which is ineffective to enrich the mixture on opening of the throttle under certain other operating conditions when enrichment of the mixture is not desirable.

According to this invention, this object is carried out by providing a fuel pump which is oper- 30' ative to supply additional fuel only on opening movements of the throttle, which take place after the auxiliary air supply passage is effective to supply additional air to the primary mixture.

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

In the drawing:

Fig. 1 is a vertical section through the carburetor unit ofa charge forming device embodying this invention.

Fig. 2 is a fragmentary, vertical section on the passage.

Referring to the drawing and more particularly to Fig. 1, the reference numeral 10 indicates the 'main housing of a carburetor unit adapted o be attached to an air manifold, of the type shown in the above-mentioned copending application, by a flange 12, which is secured to a cooperating flange on the manifold in the well-known manner.

The main housing 10, above referred to, has secured to its bottom wall, a frame in the form of a casting 14, in any desirable manner. The main housing contains the main air valve, auxiliary air valve, primary carburetors, throttles and other mechanism later more particularly described, while the frame 14 has formed therein the fuel passages conveying fuel from the float chamher to the primary carburetors, various dashpots for controlling the admission of air and other devices more fully described hereinafter. In addition, the frame 14 provides the top for a constant level sheet metal fuel bowl 16, the upper edge of which flts against a shoulder 18, formed on a projecting flange 20 of the frame 14, the bowl being held tight against the shoulder by a screw 22, screwed into a part of the frame 14, as indicated in Fig. 1. Suitable gaskets may be provided to prevent leakage.

Fuel is supplied to the bowl from a fuel supply line (not shown) and a constant level within the bowl is maintained by a float 24 in the conventional manner. An angular fuel passage 26 is provided to convey fuel from the bowl to the primary carburetorswhich will be more fully described later. The. lower horizontal portion of this passage communicates with a vertical passage 28, formed in a projecting part of the frame 14, as shown in Fig. 3, and a calibrated fuel metering plug 30 admits fuel to the passage 28 at all engine speeds, as indicated in said Fig. 3. All of the fuel supplied to the primary carburetors at all engine speeds up to that corresponding to a vehicular speed of approximately 55 miles per hour on a level, flows through the plug 30 so that said plug regulates the flow of fuel per unit of time at all speeds under that referred to, while additional fuel is admitted to the passage 26 at higher speeds through a fuel inlet 32 controlled by a valve 34, which is normally in a position to close said port, but is adapted to be lifted by means not shown herein, at approximately the speed above referred to, permitting aflow of fuel through the port 32 to augment the fuel supplied through the plug 30. The specific mechanism above described, forms no part of this invention, and reference may be had to the above-mentioned application for a more complete disclosure of this mechanism. v

The fuel passage 26 at its upper end communicates with a horizontal fuel channel 36, formed in the upper face of the frame 14 and shown in Figs. 1 and 2. This channel communicates with three calibrated plugs 38, screwed into the lower face of the main housing and each of which supplies fuel to one of the three vertical passages 40, bored in the wall of the main housing, as shownin Figs. 1 and 2. Each of the pasages 40 supplies fuel to one of three parallel primary mixture passages, indicated in their entirety by the reference numeral 42. After the valve 34 is opened as previously described, to render the port 32 effective, the calibrated plugs 38 meter or regulate the total quantity of fuel supplied per unit of time to the primary carburetors.

Each of the primary carburetors comprises an angular mixture passage having a horizontal outlet portion 44 and a vertical inlet portion 46. These passages are in substantially parallel planes and are bored in the bottom wall of the main housing. The vertical portions 46 of the mixture passages communicate with a main air chamber 48, formed in the main housing 10 and will be more fully described later. All of the air flowing through the mixture passages at all engine speeds is supplied from said main air cham- 30 ber, in which the suction at any engine speed is a static suction determined by the spring-held main air valve which controls the admission of air to. the chamber 48, as described in detail hereinafter.

Associated with each primary mixture passage to supply fuel thereto, is a fuel passage 40, previously referred to, which isformed in the wall of the main housing closely adjacent and substantially parallel to the vertical part 46 of the primary mixture passage with which it is associated. Each passage 40 is provided at its lower end with a small fuel feeding orifice 50, which supplies fuel to the primary mixture passage for idling and other low speed operations. At its upper end, each passage 40 communicates with a horizontal passage 52, bored in the wall of the main housing a short distance above the orifice 50 and having its outer end closed by a plug 54. The diameter of the passage 52, where it communicates with the passage 40, is appreciably greater than that of the latter and is provided with a restricted outlet 56, which communicates with the vertical portion 7 46 of the primary mixture passage and constitutes a main fuel feeding orifice therefor. The

' orifice 56 is inefiective to supply fuel at low speeds,

but comes into operation at intermediate speeds to augment the flow of fuel from the orifice 50 and remains effective during operations at all speeds higher than that at which it first begins to supply fuel. Bored in the wall of the main housing are three passages 58 connecting with the passages 52 and with the main air chamber 46 to communicate the suction of said air chamber to the passage 52.

- The passages 58 are considerably larger than the fuel feeding orifice 56and in view of this fact,

This throttle is journalled in a suitable recess of the same diameter as the throttle bored in the bottom wall of the main housing 10 and is operated by a mechanism fully described in the above-mentioned application, but which is not material so far as the present invention is concerned. The

primary mixture passages connect at their posterior ends with conduits formed in the manifold wall, which convey the primary mixture to secondary mixing chambers formed in the manifold where it is mixed with additional or secondary air during the operation of the engine at intermediate or high engine speeds. These conduits are fully disclosed in the above entitled application.

All of the air admitted to either primary or secondary mixing chambers, except the very small quantity of air which is admitted when the choke lever is operated to facilitate starting in the manner disclosed in the above application, enters the carburetors through an air inlet coupling 64, secured in a suitable opening in the housing by screws 66. The coupling is provided with a restricted throat 68 at the apex of two conical sur-' a sleeve80, slidable on a fixed sleeve 82, which is means disclosed in the above application, so as to lift the sleeve 80 into engagement with the valve '74 to hold the latter closed .during the starting of the engine, as fully described in the above-mentioned application. v

To prevent fluttering of the air valve and to retard its movement toward open position for the purpose of improving the operation during the acceleration period, a dashpot is provided which includes a cylinder 90 positioned within the fuel bowl and formed in the frame 14. Received within the cylinder is a piston 92, which is mounted on the lower end of the air valve stem in any desirable way. This cylinder may be mounted on the valve stem in the manner disclosed in the above application or it may be secured thereto in any conventional mannerso far as the present invention is concerned. The bottom of the cylinder 96 is closed by a cap 94, soldered or otherwise secured to the frame 14 and in the center of this cap is a valve cage 96 in which a check valve 98 is received. This check valve is arranged to permit fiow into the cylinder 90 on closing movement of the air valve, but prevents escape of fuel from the cylinder on opening movement of the valve so that the dashpot operates to retard such opening movement.

During operation at all engine speeds below that corresponding to a vehicular speed of 20 to 25 miles per hour on the level, all of the air entering the intake ports passes through the primary mixture passages, the mixture formed therein being of proper combustible proportions and of the desired quantity to properly operate the engine. At speeds in excess of the above, however, additional air is admitted to the'manifold to provide a sufficient quantity of mixture and to supply this air, a secondary air passage 100, connecting the air chamber 48 and the manifold, is provided. The flow of air through the passage 100 is controlled by two valves, a manually operable throttle 102, secured to an operating shaft 104 and a suction operated valve 106, secured to a shaft 108, the shafts 104 and 108 being rotatably mounted in the main housing. The operating connections for these two valves constitute no part of the present invention and will not be described in detail herein, it being sufficient for the purpose of this disclosure to describe very briefly the mode of operation of these valves. The primary throttle is connected to the valve 102 by a lost motion connection which is shown in Fig. 6'and which permits a predetermined movement of the primary throttle independent of the valve 102. This lost motion connection is shown only in ageneralmanner in Fig. 6; reference to Aseltine Patent 1,853,011 is made for a more complete disclosure of such a lost motion connection, as Well as of the manifold into which the primary mixing passages and the auxiliary air passage discharge. Such connection is capable of adjustment and is generally adjusted so that the primary throttle may be moved without accompanying movement of the valve 102 until the former reaches a position corresponding to a vehicular speed of approximately 20 to 25 miles per hour on a level. On further opening of the primary throttle, the valve 102 is moved simultaneously therewith, and the suction operated valve 106, which is pivoted ofi center, is adapted to be opened by the engine suction as soon as the valve 102 begins to open.

Opening movement of the suction operated valve 106 is retarded to aid in enriching the mixture by restricting the flow of air through the secondary air passage immediately after the opening of the'throttle, as fully set forth in the above application. To retard the opening movement of the valve 106, it has secured thereto by brazing or in any other suitable way, an arm 110, which projects from its anterior face. A short link 112 is pivotally connected to the arm 110 by a pin 114 and to a coupling member 118, which is screwed on the upper end of piston rod 120, as shown in Fig. 1 and fully described in the above application. The rod is loosely received within a bore 122 in the bottom wall of the main housing and pinned to the lower end of the rod is a sleeve 124, while slidably mounted on the sleeve is a dashpot piston 126, which fits within a cylinder 128, formed in the frame 14, closed at its lower end by a cap 130 securedto the cylinder in any way to effect a fluid-tight joint. As described herein, the sleeve 124 is not rigidly secured to the piston rod but is yieldingly mounted thereon so that under certain operating conditions, the piston may move relative to its operating rod in order to permit the passage of fuel from the space below said piston to relieve the resistance ofthe dashpot and allow the valve 106 to open freely. For this purpose the piston is slidably mounted'on the sleeve 124 and is held in position against a flange 132, projecting from the rod 120, by a spring 134, which is received between the piston and a nut 136 on the upper end of the sleeve 120. The piston is provided with small orifices 138, which permit the fuel to flow from the space below the piston when the latter is lifted above the flange 132.

As an example of the operating conditions under which the resistance of the dashpot is relieved in the mannerabove described, I may assume the vehicle on which the carburetor is used, to be coasting down hill at relatively high speed with the throttle closed and the clutch engaged. The engine is turning relatively rapidly under these conditions so that the manifold vacuum is very high. If the throttle be opened as the vehicle leaves the bottom of the hill, the very high manifold vacuum is communicated to the valve 106 and moves the. piston downward so that the pressure below the piston is suflicient to overcome the pressure of the spring 124 until the latter collapses and the piston is moved from engagement with the flange 132. This operation is dethe circumstances described, the engine is. already running at relatively high speed and no mixture enrichment is needed under such circumstances.

In addition to the means for restricting the opening of the auxiliary air valve in the manner described, means have been provided in devices of this character to pump additional fuel into the mixture passages when the throttle is opened to form a mixture of the proper proportions to most satisfactorily operate the engine during the acceleration period. In devices of this character heretofore designed, the pump has been effective to supply fuel on all opening movements of the throttle. It has been found, however, that when the secondary air passage is closed, the velocity of flow through the primary mixture passages is enough to create sufficient suction at the fuel jets to supply enough fuel to form a mixture of the proper proportions and to carry such mixture through the primary mixture conduits with sufiicient velocity to operate the engine properly without additional fuel beirfg supplied thereto. Accordingly, the present invention comprises means for supplying additional fuel to the primary mixture passages only after the secondary air passage becomes effective to supply additional air. pot associated with the secondary air valve is constructed to operate as a fuel pump during opening movements of said air valve and to this end a fuel delivery conduit comprising a horizontal passage 140 and a vertical passage 142 is formed within the casting 14. The passage 142 connects at its upper end with a horizontal fuel canal 144, which in turn connects with three vertical fuel delivery passages 146, each provided with a restricted outlet 148 and connecting with one of the mixture passages 42, as shown in Fig. 1. The delivery passages 146 are of the same construction as fully described in the above copending application. The passage .140 is restricted at 150 so that the provision of the passage will not appreciably reduce the retarding effect of the dashpot.

It will be obvious that on any downward movement of the piston 126, when the air valve 106 is open, the fuel will be forced through the above described passages into each of the primary mixture passages 42, to augment the normal fuel sup-.

ply delivered thereto and enrich the mixture to the desired extent to efficiently operate the en- In order to accomplish this result, the dash- 102 begins to open, there will be no operation of the fuel pump.

It is not necessary that the air valve dashpot be of the specific construction above described. In fact, any conventional form of dashpot would operate as a fuel pump to supply additional fuel to the mixture passages after the secondary air valve begins to open, but the form of dashpot disclosed is of particular advantage when associated with the pump. When the throttle is opened as above described, to maintain the speed after completion of a coast, it is desirable that the pump be ineffective as well as that the secondary air passage be unrestricted at such times. wise, the mixture would be too rich at a time when no enrichment is needed. It will be clear that with the device disclosed, the lifting of the piston 126 against the pressure of the spring 124. not only relieves the resistance of the dashpot,

but practically renders the dashpot ineffective as throttle is moved from any partly closed position.

to a more nearly open position. Under some accelerating conditions, as for example, when the 0 throttle is moved from a substantially closed to a relatively wide ,open position, or from a partly open position where the engine is running on a mixture supplied by the primary passages alone to a position where the main air throttle is 5 opened, it is desirable to have. the additional fuel supplied by the pump during a relatively long period of time in order to secure the most satisfactory operation of the engine. This result is accomplished by the provision of means for operating the pump by the auxiliary air valve which is retarded in its opening movement by a dash- ,pot. It will be clear that by the provision of such a device the time during which the additional fuel is supplied by the pump is proportional to the time required for the auxiliary air valve to open. As the opening of the latter is COYISld', erably delayed by the dashpot it will be obvious that the additional fuel is supplied by the pump during a relatively long period of time.

It is believed that the mechanism constituting this invention and parts associated therewith are described in sufiicient detail to enable a clear understanding of the invention and for a more complete disclosure of the device as a whole, ref erence may be had to the above copending application.

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 fuel and air thereto, a throttle regulating the flow therethrough, suction operated means operative on opening movements of the throttle for enriching the mixture for acceleration, said means being operative only after the throttle has reached a predetermined position.

2. A charge forming device for internal combustion engines comprising a mixture passage, means for supplying fuel and air thereto, a throttle regulating the flow therethrough, suction op- Othererated means for supplying additional fuel to the mixture passage on opening movements of the throttle, said means being operative only after the throttle has reached a predetermined postion.

3. A charge forming device for internal combustion engines comprising a mixture passage, means for supplying fuel and air thereto, a throttle regulating the flow therethrough, a pump for injecting additional fuel into the mixture passage and suction operated means for operating said pump on opening movements of the throttle, said 1 means being effective only after the throttle has reached a predetermined position.

4. A charge forming device for internal combustion engines comprising a'mixture passage, means for supplying fuel and air thereto, a throttle regulatingthe flow therethrough, a normally closed secondary air passage adapted to be opened when the throttle reaches a predetermined position, and suction operated means for enriching the mixture on opening movements of the throttle, said means being effective only after the auxiliary air passage is opened.

5. A charge forming device for internal com bustion engines comprising a mixture passage, means for supplying fuel and air thereto, a throttle regulating the flow therethrough, a secondary air passage, a suction operated valve controlling said air passage and adapted to be opened after the throttle has been opened a predetermined amount, means for enriching the mixture on opening of the throttle and connected to the suction operated air valve for operation therewith.

6. A charge forming device for internal combustion engines comprising a mixture passage, means for supplying fuel and air thereto, a throttle regulating the flow therethrough, a pump for supplying additional fuel to the mixture passage, a secondary air passage for supplying auxiliary air to the mixture passage, a suction operated valve in said air passage adapted to be opened only after the throttle has made a predetermined movement and means connecting the pump to said valve for operation therewith.

7. A charge forming device for internal combustion engines comprising a mixture passage, means for supplying fuel and air thereto, a throttle regulating the flow therethrough, a secondary air passage for supplying auxiliary air to the mixture passage, a valve in said air passage adapted.

8. A charge forming device for internal combustion engines comprising a mixture passage, means for supplying fuel and air thereto, a throttle regulating the flow therethrough, a secondary air passage for supplying auxiliary air to the mixture passage, a valve in said air passage adapted to be opened only after the throttle has made a predetermined movement, a dashpot for retarding the opening movement of said valve, afuel delivery conduit extending from said dashpot to the mixture passage and a restriction in said delivery passage.

9. A charge forming device for internal combustion engines comprising a mixture passage, means for supplying fuel and air thereto, a throttle regulating the flow therethrough, means operative on opening movements of the throttle for enriching the mixture for acceleration, said means being operative only after the throttle has reached a predetermined position, and means for rendering said enriching means ineffective on opening movements of the throttle under certain operating conditions.

10. A charge forming device for internal combustion engines comprising a primary mixture passage, means for supplying fuel and air thereto, a secondary mixing chamber into which the primary mixture passage delivers a primary mixture of fuel and air, a throttle, a secondary air passage admitting air to said secondary mixing chamber, means controlling the flow of air through said air passage and adapted to render primary mixture passage delivers a primary mixture of fuel and air, a throttle, a secondary air passage admitting air to said secondary mixing chamber, a suction operated valve controlling the flow of air through said air passage, and adapted to be opened after' the throttle has reached a predetermined position, and means operated by said valve for enriching the mixture on opening movements of the throttle.

12. A charge forming device for internal combustion engines comprising a primary mixture passage, means for supplying fuel and air thereto, a secondary mixing chamber into which the primary mixture passage delivers a primary mixture of fuel and air, a throttle, a secondary air passage admitting air to said secondary mixing chamber, suction and manually operated va'lves controlling the flow of air through said air passage, and means operated by one of said valves for enriching the mixture on opening movements of the throttle.

13. A charge forming device for internal com-. bustion engines comprising a primary mixture passage, means for supplying fuel and air thereto, a secondary mixing chamber into which the primary mixture passage delivers a primary mixture of fuel and air, a throttle, a secondary air passage admitting air to said secondary mixing chamber, a manually operated valve in said air passage adapted to be opened after the throttle has made a predetermined movement, a suction operated valve in said air passage, and means operated by the suction operated valve for enriching the mixture on opening movements of the throttle.

14. A charge forming device for internal combustion engines comprising a plurality of secondary mixing chambers, a plurality of primary mixture passages supplying a primarymixture of fuel and air thereto, means admitting fuel and air to the primary mixture passages, a secondary air passage supplying air to all of said secondary mixing chambers, means controlling the flow through said secondary air passage, a throttle and means operated by said flow controlling means for enriching .the mixture on opening movements of the throttle.

15. A charge forming device for internal combustion engines comprising a plurality of secondary mixing chambers, a plurality of primary mixture passages supplying a primary mixture of fuel and air thereto, means admitting fuel and air to the primary mixture passages, a secondary air passage supplying air to all of said secondary mixing chambers, means controlling the flow through said secondary air passage, a. throttle, and means operated by said flow controlling means for supplying additional fuel to said primary mixture passages on opening movements of the throttle.

16. A charge forming device for internal combustion engines comprising a primary mixture passage, means for supplying fuel and air thereto, a secondary mixing chamber into which the primary mixture passage delivers a primary mixture of fuel and air, a throttle, a secondary air passage admitting air to said secondary mixing chamber, a suction operated valve controlling the flow of air through said air passage and adapted to open on opening movements of the throttle, a fuel pump and means for operating the fuel pump on any opening movement of the throttle soas to supply fuel to the mixture passage for a length of time proportional to the time required for said suction operated valve to open.

1'7. A charge forming device for internal combustion engines comprising, a mixture passage, means for supplying fuel and air thereto, a throttle regulating the flow therethrough, a pump operative on opening movements of the throttle for supplying additional fuel for acceleration, means for rendering said pump effective only after the throttle has reached a predetermined position, and means for rendering said pump ineifective'on opening movements of the throttle after the latter has reached said predetermined position, under certain operating conditions.

18. A charge forming device for internal combustion engines comprising, a mixture passage, means for supplying fuel and air thereto, a throttle regulating the flow therethrough, a pump operative on opening movements of the throttle for supplying additional fuel for acceleration, means for rendering said pump effective only after the throttle has reached a predetermined position, said pump comprising an operating rod and a piston movable relatively to said operating rod under certain operating conditions, whereby the pump is ineffective on opening movements of the throttle taking place under said certain operating conditions.

19. A charge forming device for internal combustion engines, comprising, a mixture passage, means for supplying fuel and air thereto, a throttle regulating the flow therethrough, an auxiliary air valve for admitting additional air to the mix-.

ture passage, a pump operated by the auxiliary air valve for supplyingadditional fuel to the mixing chamber during the acceleration period,

' and means permitting movement of the auxiliary air valve independently of the pump under certain operating conditions.

20. A charge forming device for internal combustion engines, comprising, a mixture passage, means for supplying fuel and air thereto, a throttle regulating the flow therethrough, an auxiliary air valve for admitting additional air to the mix ture passage, a pump operated by the auxiliary air valve for supplying additional fuel to the mix- I ing chamber during the acceleration period, said pump comprising an operating rod, connected to the auxiliary air valve and piston movable relative to the rod under certain operating conditions, whereby movements of the auxiliary air valve independent of the pump are permitted.

21. A charge forming device for internal combustion engines, comprising, a mixture passage, means for supplying fuel and air thereto, a throttie regulating the flow therethrough, an auxiliary air valve for admitting additional air to the mixture passage, a pump operated by the auxiliary air valve for supplying additional fuel to the mixing chamber during the acceleration period, said pump comprising an operating rod connected to the auxiliary air valve, a piston operated by said rod, means causing the piston to move with said rod on all relatively slow opening movements of the auxiliary air valve and enabling rapid movements of the valve independently of the piston under certain operating conditions.

22. A charge forming device for internal combustion engines, comprising, a mixture passage, means for supplying fuel and air thereto, a throttle, anauxiliary air valve for supplying additional air to the mixture passage and operative only after the throttle has made a predetermined opening movement, means operable by the auxiliary air valve on opening movements thereof, for enriching the mixture during the acceleration period, and means for rendering said mixture enriching means ineffective duringopening movements of the auxiliary air valve under certain operating conditions.

WILFORD Hx 'IEETER.

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