US1898324A - Charge forming device - Google Patents

Description

Feb. 21, 1933. Y W H TEETER I1,898,324

CHARGE FORMING DEVICE ai, Mm my@ Feb. 21, 1933. W H@ TEETER 1,898,324

CHARGE FORMING DEVICE Filed Oct. 2, 1929 2 Sheets-Sheet 2 Patented Feb. 2l, 1933 UNITED STATES PATENT OFFICE WILFORD H. TEETER, 0F DAYTON, OHIO, ASSIGNOR TO DE-LCO PRODUCTS CORPORATION,

0F DAYTON, OHIO, A CORPORATION OF D-ELAW'ARE CHARGE FORMING DEVICE Application filed October 2, 1929. Serial No. 396,703.

This invention relates to charge forming devices for internal combustion engines and more particularly to devices of this character which comprisera plurality of primary carburetors, which deliver a primary mixture of fuel and air to a pluralityof secondary miX- ing chambers located adjacent the engine intake ports and in which the primary mixture is mixed with additional air under'certain operating conditions.

OneA example of a device of this character is disclosed in the patent of `Wilford H. Teeter, 1,819,526, granted August 18, 1931.

1t is the principal object of the present invention to provide means for more accurately proportioning the mixture of fuel and air under various different operating conditions. More particularly, it is an object of this invention to provide means for securing a more nearly' correct fuel miX- ture and making the device less sensitive dur- Y ing the idling operation, for improving the engine operation during the acceleration period immediately following any opening movement of the throttle and at high speed with the throttle relatively Wide open.

According to the present invention, all of these results are obtained by the provision of a specific form of air valve, which is controlled by a spring of the desired strength in the manner fully set forth hereinafter inthe body of the specification. Y

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

In the drawings:

Fig. 1 is a vertical, longitudinal section through a charge forming device constructed according to the present invention and an engine intake port with which it is associated.

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

Fig. 3 is a detail view of a valve controlling admission of fuel-to the nozzles under certain operating conditions.

Fig. 4 is a detail view of a fuel pump for tioned application.

supplying additional fuelduring the acceleration period. j

Fig. 5 is a side elevation seen from a direction opposite to Fig. 1.4

Fig. 6 is a fragmentary side elevation `5 showing the throttle operating mechanism.

Referring to the drawings, 10 indicates a main air manifold, provided with three outlet branches, each of which communicates with an intake port of a conventional siX- cylinder engine, the middle outlet branch 12 and port 14 associated therewith being disclosed in Fig; 1. Each outlet branch is provided with an attaching flange for securing the manifold to the engine block in the usual manner and a'ange 18 is provided at the manifold'inlet, to which the carburetor unit may be attached.

The carburetor unit comprises an outlet conduit 20, .and distributor block 21 secured together in any desirable way and provided with an attaching flange 22, secured to the flange 18 by screws 24; and a vhousing 26 is secured to the outlet conduit 2() in a manner fully shown and described in the above men- 7 5 The housing 26 supports above it an air inlet coupling 28, secured in any desirable way to register with an opening in the upper end of the housing 26. Secured to the lower end of the housing, by means not shown herein, but fully shown in the above mentioned application, is a frame 30 to which a sheet metal fuel bowl 32 is secured by screws 34, as indicated in Fig. 1.

Fuel is supplied to the fuel bowl 32 from a main source of supply through a conduit, which is not shown, and the level of fuel in the fuel bowl is maintained constant in the conventional way by means of a float36. 90 Fuel is conveyed from the fuel bowl to calibrated plugs 38 communicating with primary miXing chambers 40, formed in the distributing block 21, hereinbefore referred to, by a pipe V42 screwed into a downwardly projecting portion 44 of a plate 46, secured in any desirable way to a block 48, supported in position on the bottom face of the distributor block 21 by any suitable means. Pipe 42 communicates with a chamber 50 within the pro- 100 CII jection 44, in which is received a two-stage fuel metering` valve 52, normally seated in the restricted inlet 54 of said chamber and fuel supplied through the pipe 42 can flow only through a small orifice 56 in said valve, but at higher speeds when the engine suction is greater, the valve is adapted to be lifted to permit a flow of fuel through the chamber 50 around said valve in the manner fully described in the above mentioned application. The chamber 50 communicates through a restricted orifice 58 with a horizontal fuel channel 60 formed in the block 48, which in turn Asupplies fuel to three vertical passages 62, each of which communicates with one of the calibrated plugs 88, hereinbefore referred to.

Fuel is supplied -t-o the pipe 42 at all times through a calibrated plug 64 having a fixed orifice therein and at speeds above a certain predetermined speed a passage 66 which communicates with the passage 42 immediately above the plug 64,v as indicated in Fig. The admission of fuel through the passage 66 is controlled by a valve 68, which normally closes fuel ports 70, but which is adapted to be lifted by means disclosed in the earlier application at a predetermined engine speed to supply additional fuel to the pipe 42. Fuel is lifted from the fuel bowl to the primary mixing chambers by the suction therein. On reduction of the mixing chamber suction following the opening movement of the throttle, the fuel column might drop sufficiently to starve the engine unless means were providedto prevent this action. Such a means comprises a check valve 72 received in an enlarged chamber 74, immediately above the chamber 50. On reduction in mixing chamber suction, this valve seats on the bottom of the chamber 74 and prevents downward flow of fuel.

Three primary mixing chambers 40 are formed in the distributor block 21 and are parallel and relatively close together therein, as shown in Fig. 2. The calibrated plugs 38 admit fuel to the chambers 40 immediately in advance of air inlet bushings 76, which are positioned at the anterior ends of said chambers 40 and communicate directly with an air chamber 78 formed in the housing 26 and to which air is admitted through the opening 80, which communicates with the atmosphere. The specific form of these air inlet bushings is not material to the present invention, but such bushings and their funetion are specifically described in the earlier copending application above referred to.

Three passages 82 supply air to the primary mixing chambers posterior to the fuel inlet plugs 88 so as to reduce the velocity of air flowing through the 'bushing 7 6 past said plugs. These passages communicate with a seeondary'air passage hereinafter described,

` and a baille 84, projectionr into said passage,

operates to force some of the air flowing through such passage to pass through the passages 82. A horizontal passage 86, immediately above the chambers 40, communicates with such passages and with the passages 82 through orifices 88 and 90 respectively, for the A urpose of equalizing pressure in all of the chambers 40.

A single throttle valve 92, which extends across all of the chambers 40, controls the flow therethrough and is provided with grooves 94, which register with said chambers. This throttle is operated in a manner hereinafter more fully described.

All of the air entering the carburetor except that which flows through the passage 80, is admitted through the coupling 28 and is controlled by a main air valve 96, which is normally held against a seat 98 in the position shown in dotted lines in Fig. 1, by a spring` 100, received between the valve and a flange 102, projecting from a` sleeve 104, slidable on a stationary sleeve 106 integral with the housing 26. When it is desired to choke the carburetor to facilitate starting, the sleeve 104 is adapted to be lifted into position to hold the air valve closed by a bifurcated lever 108 having pins 110 engaging the flange as indicated in Fig. 1. Sutilcient air to carry starting fuel to the cylinders is supplied through the orifices 80, previously described.

The air valve controls the admission of air to an air chamber 112, which is formed partly in the coupling 28 and partly in the housing 26, being separated from the chamber 78'by a partition 114, which is provided with a centrally arranged opening 116 to facilitate assembling. This opening is, however, normally closed by a plate 118, which is provided at its center with an opening in which an rip-standing sleeve 120 is secured to serve as a guide for the air valve stem 122.V The air admitted to the chamber 112 flows through a secondary air passage 124, which connects with the inlet of the manifold 10 and the flow of air through this passage is controlled by a manually operable air throttle 126, secured to a shaft 128, rotatably mounted in the housing 20 and operated through the medium of the primary throttle, as will be more specifically described hereinafter.

The specific mechanism for operating the two throttle valves is shown in 6 and is briefly described hereinafter. An arm 98 is secured to a spindle projecting from one end of the throttle valve 92 and is adapted to be connected to some suitable form of operating connection which extends to a point convenient to the operator of the vehicle. Pivotally connected to this arm is a link 9.7 having a slot 99 through which extends a pin 101 projecting from arm 103 secured to the shaft 128 to which the air throttle 126 is secured. This mechanism constitutes a suitable lost motion connection for operating the valve 126 from he primary throttle 92, the lost motion of pin 101 permitting independent opening of the throttle 92 to a position corresponding to a vehicular speed of approximately 15e20 miles per hour von a level.

On opening of one or both of the throttle valves or on increase in speed of the engine withfixed throttle, the suction in the air chamber 112 is increased and the valve 96 is opened to admit additional air and increase the quantity of mixture supplied to the engine. The opening of this valve is retarded to prevent flutteing ofthe valve and also to enrich the mixture during the acceleration period by means of a dashpot which comprises cylinder 130, closed at its lower end by a plug 132, and guided for vertical movement in a tubular guide 134, formed inteofrally with the frame 30. An opening 136 is provided in said guide to permit fuel to flow into the cylinder through an openingV 136 formed in the cylinder wall and registering with the opening 136, as described in the above mentioned earlier application. Cooperating` with the cylinder 130 is a piston 140 which is resiliently. mounted on the lower end `of the air valve stem 122. The ,specific means for mounting the pistonrll() comprises no part Vof this invention and it is sufficient to say herein that the piston is received on a sleeve 142, which is secured to the air valve stem and that said piston is adapted to move relative to the sleeve when the suction eifective to open the air valve is greatly increase-d so that the dash pot yields under such conditions, but under all other operating` conditions, thepiston is adapted to move as a unit with the valve stem.

ln order to increase Athe resistance of the dashpot above its normal resistance on any opening movement of the throttle valve, means are. provided to lift the cylinder 130 as the throttle is opened. rlhe operating connections from the throttle to the dashpot cylinder comprise a cam 105 secured to the shaft 128 which is operated bythe throttle as previously described. This cam is adapted to engage an arm 107 pivoted on the main housing at 109 and connectedby a link 111, having a turn-buckle 11S to adjust its length, with any one of the holes 115 in an arm 117 secured to the shaft 150, the rocking of which operates the cylinder 130 as described. Obviously opening movement of the valve 126 results inv depression of arm v167, link 111y and arm 117 roel ing the shaft 150'to left cylinder 130 by means of the yoke 152.

An additional means for enriching the mixture consists of a pump for supplying additional fuel on opening movements of the throttle. The above described dashpot forms the pump and a fuel delivery conduit communicates with the cylinder 130 near the bottom thereof. This delivery conduit comprises an orifice 160 in the wall of the cylinder 130 which communicates with an angular nipple 162, which has threaded on its end a valve cage 164 containing a check valve 166 normally held closed by spring 168. Connected with the valve cage at its upper end, is a tube 170, which is bent at its upper end and ext-ends into the air intake c0upling28. @n downward movement of the dashpot piston, the fuel below said piston is forced through the delivery conduit into the air intake, Vas fully described in the above mentioned, earlier application.

According to thepresent invention, the air valve 96 instead of being a plain poppet valve of the type shown in the Vearlier application,

is partly cylindrical in form, as indicated at 172, and in normal position of the valve, as shown in dotted lines in Fig. 1, vthis cylindrical portion extends within a restricted throat 17 4 in thev air intake coupling and is somewhat smaller than the interior diameter of this throat. Below the cylindricalpart ofthe valve, it is flared outwardly, as indicated at 176 and the flared portion normally engages the seat 98 when the valve is in closed position.

This valve effects a plurality of desirable results and overcomes certain functional difficulties which occur under certa-in operating conditions with a structure such as shown in the earlier application. Among the beneficial results obtained by this form of air valve are more accurate mixture proportioning and satisfactory engine operation at idling. These results are secured because an air valve of the type disclosed herein is much less sensitive and more positive in its operation at idling speeds than the ordinary poppet type valve such as employed heretofore. The latter opens the air intake opening to so great an extent on so slight a movement of the valve that it has been found very difficult to construct any one device so accurately as to function in exactly the manner desired at all times and more difficult to construct any two which function exactly alike. With a valve of the design disclosed herein, however, the valve has to make an appreciable movement before there is any substantial increase in the size of the air intake. Therefore, small variations lin the strength of the air valve spring or in the resistance of the dashpot, or other variations which may be encountered, have but little effect on the position assumed by the valve or the air intake controlled thereby. For this reason with a valve constructed in accordance with the present invention, the area of the air intake opening and the position of the valve is substantially the same for any given engine suction regardless of slight structural variations.

An additional advantage secured by this type of valve is improved engine operation during the acceleration period dueto the prolongation of the period during which the mixture is enriched following an opening of the throttle, particularly when the engine is operating at relatively lovv speed When the throttle is opened. ln this design of charge forming device, the mixture is enriched during the acceleration period by restricting` the admission of air, first during the actual closing of the air valve by the lift-ing of the movable cylinder i30 as the throttle is opened, and after this by the retarding effect of the dashpot as the valve slowly opens until it assumes a position determined by the position to which the throttle has been moved; also by pumping of additional fuel into the mixture during the movement of the valve. In this device, the closing movement of the valve, which is effected by the movable cylinder on opening of the throttle, is greater than in a device having the ordinary type of valve because for any given throttle position, the valve in this device must be moved further from the valve seat to admit the quantity of air demanded by the engine for that particular position of the throttle. @n further opening of the throttle, therefore, particularly from a relatively low speer position, the distance through which the valve can be moved toivard closed position by the lifting of the dashpot is greater and the subsequent opening movement to Whatever ultimate position the valve assumes is also greater. The movement of the valve being, therefore, greater in both directions, it is obvious that the time during which the admission of air past the valve is restricted because of the control of t-ie valve by the dashpot is also increased. Further, the period during which the pump is effective to supply fuel also increased because of the increase in downward movement of the valve, and it has been found that this prolongation of the period during which the mixture is enr'ched following opening of the throttle produces more satisfactory operation of the engine.

Another desirable result which is brought about by a valve of the type disclosed, is improved engine operation at high speed 'ith ivide open throttle. ln certain designs of devices of this character, it has been found that if sui'iicient ai is supplied at certain intermediate and low speeds to provide a mixture of proper proportions, there is too much air at wide open throttle and the mixture becomes too lean. ln other Words, if the device is so calibrated that suiiicient fuel is admitted at high speeds, the mixture is too rich at lower speeds and vice versa. By providing an a': valve of the type disclosed, the air inlet is not of as greatarea when the air valve is fully open as When the ordinary poppet type of valve is employed because the cylindrical portion 172 imposes some restriction, by comparison With the poppet type of valve, even at Wide open throttle. This construction malres it possible, therefore, to easily calibrate the device so as to form a proper mixture and also permits the use of a spring on the air valve having a less initial tension than has been possible heretofore. rlhis is also desirable because when a relatively stid spring is used, there is a tendency to restrict the admission of air too much at low speeds in order for the valve to be properly positioned at high speeds, resulting in too rich a mixture. It has been attempted to obviate this difficulty by the use of tivo springs to control the air valve, one of which is relatively short and is not engaged by the air valve "'l itis aartially open, so as to increase the nce opening m vement of the valve approaches open position. The present valve construction eliminates the use of such a spriW or any other means for increasing the resstance of tie valve to opening movement as it nears open position.

The primary mixing chambers communicate with conduits of the form shown in the earlier application which convey the primary mixture to secondary mixing chambers formed in each outlet branch of the manifold. Vlhe conduit associated with the middle outlet branch is indicated by the reference number 180 and the secondary mixing chamber is formed by the Venturi tube 182 as in the earlier 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.

Vfhat is claimed is as follows:

l. A charge forming device for internal combustion engines comprising a mixture passage, means for supplying fuel thereto, a throttle, an air inlet passage, and a valve controlling the flow through said air passaid valve having a substantially cylindrical portion adapted to extend into the air inlet passage When the valve i in closed position, and spaced from the Wall of said air inlet passage, to regulate the flow of air therethrough.

2. A lifirge forming device for internal bustion engines comprising a mixture p means for supplying fuel thereto, a throttle, an air inlet passage, and valve controlling the lioiv through said air passage,

l valve having a substantially cylindrical po JLon adapted to extend into the air inlet passage when the valve is in closed position and designed to constitute the greatest restriction in the air passage when the air valve in fully open position.

il charge formingl device for internal combustion engines comprising a mixture passage, means for supplying fuel thereto, a throttle, an air inlet passage, a restriction'in said air passage constituting a valveseat, and a valve for controlling the ow through said passage, said valve having a projecting portion adapted to extend Within the restriction when the valve is in closed position, and adapted tol regulate the flow of air through said air passage after the valve is moved from its seat. l

4. A charge forming device for internal combustion engines comprising a mixture passage, means for supplying fuel thereto, a t rottle, an air inlet passage, a restricted throat in said air passage and a valve forv controlling the flow through said air passage f having a projecting portion extending Within the throat whenV the valve is closed and adapted to restrict the flow of air When the valve is open, and a flange projecting therefrom and adapted to engage the throat.

5. A charge forming device for internal combustion engines comprising a mixture passage, means for supplying fuel thereto, a throttle, an air inlet passage, a restricted throatin said air passage constituting a valve seat and a valve cooperating therewith, said valve having a projecting portion extending Within the throat and spaced therefrom to permit the passage of air between said projecting portion and the throat While restricting the flow of air, and a ilange extending from said projecting portion and adapted to engage the throat to close the air passage.

6. A charge forming device for internal combustion engines comprising a mixture passage, a throttle, a fuel inlet therefor, an air inlet, and means controlling the propertions of air and fuel in the mixture whereby leaning of the mixture is prevented during operation at high speeds With the throttle relatively Wide open comprising an air valvel for regulating the flow through said air inlet, said valve having a projecting portion extending into and spaced from said airinlet when the valve is closed and adapted to cooperate with said inlet to restrict the incoming air when the valveis fullv open.

7. A charge forming device for internal combustion engines comprising a mixture passage, means for supplying fuel thereto, a throttle, an air inlet passage, a valve controlling the flow of air through said air passage comprising a projecting portion extending into said passage When the valve is in closed position and effective to limit the flow of air past the valve when the latter is open, and means for retarding the opening movements of said valve.

S. A charge forming device for internal combustion engines comprising a mixture passage, means for supplying fuel thereto, a throttle, an air inlet passage, means for enriching the mixture on opening movea throttle, an air inlet passage, means for enriching the mixture on opening movements of the throttle comprising a valve control-V ling the flow of air through the air passage and having a projecting portion extending into the air passage When the valve is in closed position and adapted to regulate the. flow of air through said air passage as the valve `isopened, a dashpot for -retarding the opening movements of said air valve and means for increasing the resista-nce of said dashpot on opening movements of the throttle.

l0. A charge forming device for internal combustion engines comprising a mixture passage, means for supplying fuel thereto, a throttle', an air inlet passage, means for enriching the mixture on opening movements comprising a valve controlling the flow of.

air throughthe air passage and having a projecting portion extending into the air passage When the valve is in closed position and adapted to regulate the How of air through said air passage as the valve is opened, a' dashpot for retarding the opening 'movementsv of said air valve, andy means for moving the cylinder of the dashpot in a direction opposite to the movement of its piston on opening movements ofthe throttle to increase the resistance of the dashpot.

1l.. A charge forming device lfor interna-lros combustion engines comprising a mixture passa-ge, means for supplying fuel thereto, a throttle, an air inlet passage, means for enriehingthe mixture on opening movements of the throttle comprising a valve controlling the flow of air through the air passage and having a projecting portion extending into the air passage When the valve is in closed position, and means for temporarily moving the air valve toward closed position: on any opening movement of the throttle;

l2. A charge forming device for internal f combustiony engines comprising a mixture passage, means for supplying fuel thereto, a throttle, an air inlet passage, means for enriching the mixture on opening movements of thethrottle comprising a valve controlling the ilovv `of air through the air passage' and having a projecting portion extending, into the air passage When the valve is in closed:

position and adapted to regulate the loW of air through said air passage as the valve is opened, and means for temporarily Inoving the air valve toward closed position on any opening movement of the throttle, said means comprising a dashpot including a piston connected with the valve and a cylinder adapted to be moved in a direction opposite to the direction of movement of the piston as the throttle is opened.

13. A charge forming device for internal combustion engines comprising a mixture passage, means for supplying fuel thereto, a throttle, an air inlet passage, means for enriching the mixture on opening movements of the throttle comprising a valve controlling the iioW of air through the air passage and having a projecting portion extending into the air passage when the valve is in closed position and adapted to regulate the flow of air through said air passage as the valve is opened, and means for temporarily moving said air valve toward closed position and for supplying additional fuel to the Vmixture passage on opening movements of the throttle.

1li. A charge forming device for internal combustion engines comprising a mixture passage, means for supplying fuel thereto, a throttle, an air inlet passage, means for enriching the mixture on opening movements of the throttle comprising a valve controlling the iiow of air through the air passage and having a projecting portion extending into the air passage when the valve is in closed position and effective to limit the flow of air past the valve when the latter is open, and a device for retarding the opening movement of said air valve and for simultaneously supplying additional fuel to the mixture passage on opening movements of the throttle.

15. A charge forming device for internal combustion engines comprising a mixture passage, means for supplying fuel thereto, a throttle, an air inlet passage, a valve controlling the flow of air through said air passage comprising a. project-ing portion extending into said passage when the valve is in closed position and eifective to limit the flow of air past the valve when the latter is open, and a dashpot for retarding the opening movements of said valve, said dashpot constituting a fuel pump for supplying additional fuel to the mixture passage 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 said passage delivers a primary mixture of air and fuel, a secondary air passage for supplying air to said mixing chamber, a restricted throat in said air passage and an air valve for controlling the flow through said air passage, said valve having a projecting portion adapted to extend into said restricted throat when the valve is closed, and to restrict the flow of air through said air passage when the valve is open.

17.- 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 said passage delivers a primary mixture of air and fuel, a secondary air passage adapted to supply air to the primary mixture passage and secondary mixing chamber, a restricted throat in said air passage, and an air valve for controlling the How through said air passage, said valve having a projecting portion adapted to extend into said restricted throat, said restricted `portion loeing spaced from the throat so as to admit a limited quantity of air when the valve is slightly open at low engine speeds, and to restrict the air iioiv at higher speeds.

18. A charge forming device for internal combustion engines comprising a mixture passage, means for supplying fuel thereto, a throttle, an air inlet passage having a valve seat formed thereon, a valve cooperating With said seat to open or close said air passage, said valve having a projecting portion extending into and spaced from the Wall of said air passage to restrict the flow of air when the valve is open.

19. A charge forming device for internal combustion engines comprising a mixture passage, means for supplying fuel thereto, a throttle, an air inlet passage of cylindrical form having a Valve seat formed thereen, a poppet valve cooperating With said seat to open or close said air passage, said air valve having a cylindrical projecting pcrti'on extending into and spaced from the Wall of said air passage to restrict t-he flow of air when the valve is open.

In testimony whereof I hereto affix my signature.

WILFORD H. TEETER.

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