US1884962A - Charge forming device - Google Patents

Description

Oct; 25, 1932. F. E. ASELTINE CHARGE FORMING DEvicE Filed Sept. '7. 1929 2 Sheets-Sheet JM (a Oct. 25, 1932.

F. E. ASELTINE CHARGE FORMING DEVICE Filed Sept. 7.- 1929 2 Sheets-Sheet k 2 Q----S s I Jmmtoa J i. W

as, f M, Mm. 554

Patented Oct. 25, 1932 UNITED STATES PATENT OFFICE FRED E. ASELTINE, OF DAYTON, OHIO, ASSIGNOR TO DELGO PRODUCTS CORPORATION, OF DAYTON, OHIO, A CORPORATION OF DELAWARE CHARGE FORMING DEVICE Application filed September 7, 1929. Serial No. 391,058.

This invention relates to charge forming devices for internal combustion engines of the type comprising a plurality of primary carburetors, which deliver a primary mixture of fuel and air to a plurality of secondary mixing chambers located adj acenttli'e eng ne It is the principal object of the present invention to provide a device of this character I which is eflective to supply a more homogeneous mixture than has been possible with earlier forms of such devices, and which is effective under all operating conditions to secure equal distribution of such mixture to the various engine intake ports, particularly during the acceleration period following any opening movement of the throttle.

It is a more specific object of this invention to provide an intake manifold which conveys the air' and fuel mixture to the engine intake ports with means for increasing the velocity of flow of the fuel mixture through the manifold without materially restricting the passage therethrough at open throttle position whereby better distribution of such mixture is secured with substantially no reduction in the volumetric eflicienc of the engine.

Further objects an 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.

In the drawings:

Fig. 1 is a plan vew of a charge forming device constructed in accordance with the present invention.

on the'line 3-3 of Fig. 2.

Fig. 2 is a vertical, longitudinal section through the charge forming device on the line 2-2 ofFig. 1.

Fig. 3 is a fragmentary, transverse section Fig. 4 is a fragmentary, front elevation of the manifold showing the inlet which is adapted to communicate with the carburetor unit.

Fig. 5 is a section through the manifold on 55 the line 5-5 of Fig. 1.

The device disclosed comprises a main air manifold 10, having three outlet branches 12, 14 and 16. Each of these branches communicate with one of the intake ports of a multicylinder engine and each is provided with an attaching flange 18 for securing the manifold to the engine block in the usual manner,

while flan e 20 to which the carburetor unit is lsgcured is formed at the inlet of the mani- The carburetor unit comprises a main housing 22, having an attaching flange 24, adapted to be secured to the flange 20 by screws 26. An air inlet coupling 28 is secured in position to register with an opening in the upper wall of thehousing 22 in any suitable way and may be connected with an air cleaner if desired. A casting 30, in which the passages supplying fuel to the nozzles are formed, is secured by screws to the lower wall of the housing 22, and a sheet metal fuel bowl 32 is held tight against an annular shoulder 34 on the housing by any suitable means. Fuel is conducted from a main source of supply to the fuel bowl through a conduit (not shown) and the flow of fuel to the bowl is controlled by a float 36 operated in the usual manner to maintain a substantially constant level of fuel therein..

Fuel flows from the bowl 32 to a plurality of primary fuel nozzles 38, one of which is located in each of the primary mixing chambers 40, the construction of which is briefly described hereinafter. The fuel conduit between the fuel bowl and the nozzles comprises a vertical fuel passage 42 commun1 eating at its upper end with a horizontal fuel canal 44, which connects with each of the nozzles 38 through an orifice 46. Fuel is admitted from the fuel bowl to the passage 42 at all engine speeds through a fixed metering orifice 48, and at high speeds, additional fuel is admitted through an orifice 50, controlled mby a valve 52 operated in the manner set the above described fuel passages and nozzles 38 to the primary mixing chambers by the suction therein. Opening movements of the throttle cause a reduction in the mixing chamber suction which might permit the fuel column to drop sufliciently to cause a temporary fuel starving of the engine unlessmeans are provided to prevent this action. For this purpose a check valve 54 is provided in an enlarged chamber 56 at the junction of the channels 42 and 44 and on reduction of the mixing chamber suction, seats on the bottom of said chamber and prevents downward flow of fuel.

Each nozzle is provided with amain fuel outlet 58 in the top of the nozzle, and a secondary fuel outlet comprising two orifices 60 wind 62 in the vertical wall of the nozzle near thebottom of the mixing chamber. At relatively high speeds, the mixing chamber suction is sufiicient to lift fuel from the main outlet as well as from the orifices and 62.

At idling, or low speed operation under load,

to the manifold, these passages communicate with conduits conveying the primary mixture to the secondary .I'nixing chambers, as

fully described hereinafter." Restrictions 66 separate the primary mixing chambers from the remainder of the mixture passages to reduce the velocity of flow past-the fuel nozzles for the purpose fully set forth in the above mentioned co-pending' application.

' is'operated in the manner hereinafter more memes fully described and serves not only to control the flow through the passages 64, but also to open and close air passages 71, which admit air to the primary mixture passage in advance of the restrictions 66 for the purpose fully described in said earlier application.

retor flows through the coupling 28 and is controlled by a main air valve 74, normally held against a seat 76, by a spring 78, received between the valve and flange 80, projecting from a sleeve 82, slidably mounted on a stationary guide sleeve 84, fixed in the main housing and serving also as a-guide for the stem 86, to which the air valve is secured. When it'is desired to choke the carburetor to aid in starting, the flange 80 is adapted to be lifted by means notshown herein but fully described in the above application, until the upper end of the sleeve 82 engages the air valve to hold it closed. Sufiicient air to carry the starting fuel from the nozzles to the cylinders is admitted through an el0n-' gated slot 87, formed in a plate 88, secured to the housing 22, as shown in Fig. 2.

The valve 74 admits air to the air chamber .90 from which air flows to the primary mixture passage through an orifice 92 in the bottom of the air chamber and to the secondary mixing chambers through a passage 94, which connects with the inlet of the manifold 10. The flow of air through this passage is controlled by a manually operable throttle 96, secured to a shaft 98, rotatably mounted in the housing 22, and by a suctionfoperated valve 100, fixed on a shaft 102, also rotatably mounted in the main housing.

two throttle valves form no part of the present invention and are not described herein, it being suflicient for the purposes of this disclosure to describe briefly the mode of operation of these valves. The primary throttle is connectedto the valve 96 by a lost fmotion connection which permits a certain predetermined movement of the primary throttle independent of said valve 96. The lost motion connection may be adjusted and in gen eral practice is so adjusted that the primary throttle may be moved without accompanying movement of the valve 96 until the former reaches a position corresponding to a vehicular speed of approximately 15 to 20 miles per hour on the level. On further opening of the primary throttle, the air throttle is moved simultaneously therewith.

On opening of one or both of the throttle valves, the suction in the air chamber 90 is increased and the valve'74 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 fluttering of the valve and to prevent temporary leaning of the mixture immediately followmg an opening movement of the throttles.

Nearly all of the air entering the carbu- Thespecific operating connections for the v I as struction of this dashpot is not material so.

'far as the present invention is concerned, and it may be of any conventional form which will properly retard the opening of the air.-

valve.

As hereinbefore stated, the valve 100 is opened by engine suction when the air throttle 96 is opened. In certain earlier devices of this type, a dashpot has been provided for the purpose of retarding the opening of this valve. The purpose of this dashpot and its construction are fully described in the prior application, but its function is' briefly set forth here in order to facilitate a clearer understanding of the present invention. If the valve 100 were permitted to open freely, the air admitted through the passage 94 would reach the secondary mixing chambers before the increased quantity of primary mixture, resulting from the opening of the throttle, and the mixture formed in the secondary mixing chambers would, therefore, be too lean temporarily to properly operate the engine immediately following any opening of the throttle. By retarding the opening I of the valve 100, the time required for the air supplied through the passage 94 to reach the secondary mixing chambers becomes substantially that required for the increased supply of primary mixture to reach said chambers.

In order to enrich the primary mixture on opening movements of the throttle, the above described dashpot is constructed to operate as a fuel-pump. To this end a fuel delivery conduit 110 connects with thebottom' of the dashpot cylinder and extends to a horizontal passage 112, formed in a distributor block 114, secured to the lower face of the main housing in any suitable manner. The channel 112 communicates with three vertical channels 116, one of which is shown in Fig. 2, which in turn communicate with passages 118 formed in the wall of the main housing and communicating with each of the mixture passagesj Passages 120 are formed within the block 11 1 and admit air from the space above the fuel in the reservoir 32 to the channel 112 to form an emulsion of fuel and air which is drawn into the primary mixture passages through the passages 116 and 118 in the manner fully described in the earlier application above referred to.

It has been found diflicult to'secure sufiicient velocity of flow through the primary 'at wide open throttle. present invention, means have been provided mixture passages to secure proper fuel distribution and enable satisfactory engine operation when operating at intermediate speeds with the valves96 and 100 partially open, particularly during the acceleration period immediately following any opening of the throttle, even by retarding the opening of the valve 100, as previously described. Where the air passing such valve is permitted to flow through the entire area of the manifold conduit, the velocity of flow therethrough must be relatively small at any but relatively high engine speeds with wide open throttle. There is, therefore, insuiiicient velocity of flow past the ends of the primary mixture conduits to create enough velocity in said conduits to supply sufficient fuel to form a mixture of proper proportions un-.

less some passage restricting means is employed within the manifold branches to increase the velocity of flow past the ends of the primary mixture conduits, suchfor instance, asthe Venturi tubes employed in the device disclosed in the above mentioned application. IPassage restricting means of this character are objectionable because they reduce the volumetric eificiency of the engine According to the to increase the velocity of flow through the primary mixture conduits whenever the valve .96 is opened without materially restricting the area of the main conduit through the manifold.

For this purpose the manifold is provided with a partition 130 formed therein when the manifold is cast and extending from a point substantially adjacent the inlet of said manifold through the lateral branches ofthe manifold numbered 132 and 134 and through all of the outlet branches 12, 14 and 16 of said manifold. .This partition; divides the manifold into two passages, 136 below the partition, and 138 above said'partition, both of these passages communicating with the passage 94 in the carburetor unit. The passage 136 is always open so that any air passing through the passage 94 may flow into the passage 136, and through such passage to the intake ports.

- The passage 138, on the other hand, is normally closed by a suction operated valve 140,

which is secured to a shaft 142 positioned 05 center with respect to the valve and rotatably mounted in the manifold wall. The upper edge of the valve is adapted to engage a fixed stop 14% and is normally held in closed position in engagement with said stop by a tension spring 1 16, one end of which is connected to a lug 1 18, projecting within the passage 138 and the other end to a pin 150 projecting from the shaft 142. The passage 136, as above stated, is in communication with the passage 94 at all times and air will pass through the passage 136 whenever the valves branches.

w and communicate with tubes 154.

96 and 100 are open. The spring 146 which holds the valve 140 closed, resists the opening of the valve 140 to a greater degree than opening of valve 100 is opposed so that the valve 140 does not open until the valve 100 is opened relatively wide and the engine is running at relatively high speed.

As previously stated, passages 64 communicate with conduits for conveying the primary mixture to the passage 136 in the variout outlet branches of the manifold. These conduits include passages formed in the manifold casting, there being a straight passage 152 in the middle which communicates directly with the passage 136 formed in the middle outlet branch of said manifold, and two outer passages 153 which are angular in form, as indicated in dotted lines in Fig. 1, Those are connected at their opposite ends to elbows 156, which in turn communicate with passages in end branches 12 and 16 of the manifold similar in form to the passage 152 previously described and communicating with the passages 136 in each of said all of the fuel flowing to the secondary mixing chambers flows through the passage 136, and of course, at a considerably greater velocity than would be the case if the manifold consisted of one enlarged passage only. At

still higher engine speeds the valve 140 begins to open and gradually opens wide as the throttle approaches wide open position. It will be clear, therefore, that at all times the velocity of air past the primary mixture conduits is greater than in earlier forms of this device and where no fixed restriction is provided, such as a Venturi tube, the volumetric efliciency of said engine is not reduced during operation at any speed.

lVhile 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, allcoming within the scope of the claims which follow. lVhat is claimed is as follows:

1. A charge forming device for internal combustion engines comprising an intake p1pe communicating with the engine intake port, a primary mixture passage delivering a mixture of fuel and air to said pipe, means for supplying fuel and air to said mixture passage, means for accelerating the flow at the point of delivery of the primary mixture passage comprising means for dividing the intake pipe into two passages and means for mixture passage, means for supplying fuel.

and air thereto, an intake pipe commumcat ing with the engine intake port, means dividing said intake pipeinto two passages into one of which the primary mixture passage delivers fuel mixture and means for normally preventing flow through the other of said passages.

4. A charge forming device for internal combustion engines comprising a primary mixture passage, means for supplying fuel and air thereto, an intake pipe communieating with the engine intake port, means dividing said intake pipe into two passages into one of which the primary mixture passage delivers fuel mixture and a suction oper-- ated valve in one of said passages for regulating the flow therethrough.

5QA charge forming device for internal combustion engines comprising a primary mixture passage, means for supplying fuel and air thereto, an intake pipe communicating with the engine intake port, means divid ing said intake pipe into two passages into one of which the primary mixture passage delivers fuel mixture and a normally closed suction operated valve in one of said pas sages adapted to be opened at relatively high engine speeds.

6. A charge forming device for internal combustion engines comprising a primary mixture passage, means for supplying fuel and air thereto, an intake pipe communicating with the engine intake pprt, means dividing said intake pipe into two passages into one of which the primary mixture passage delivers fuel mixture, means for normally preventing a flow through the other of said passages, and means for rendering said flow preventing means ineffective at relatively high engine speeds.

7. A charge forming device for internal combustion engines comprising a carburetor unit provided with means for forming a primary mixture of air and fuel and a manifold associated therewith having a plurality of outlet branches adapted to supply a combustible mixture to the engine intake ports, each of said branches having a plurality of air passages formed therein and'means for delivering the primary mixture to one of said passages.

I combustion engines comprising a carburetor unit provided with means for forming a primary mixture of air and fuel and a manifold associated therewith havinga plurality of outlet branches adapted to supply a combustible mixture to the engine intake ports, each of said branches having aplurality of air passages formed therein, means for delivering the primary mixture to one of said passages, and means for admitting air only to another of said passages.

9. A charge forming device for internal combustion engines comprising a carburetor unit provided with means for forming a primary mixture of air and fuel and a manifold associated therewith having a plurality of outlet branches adapted to supply a combustible mixture to the engine intake ports, each of said branches having a plurality of air passages formed therein, means for delivering the primary mixture to one of said passages, means for admitting air only to another of said passages and a valve therein for controlling the flow of air therethrough.

10. A charge forming device for internal combustion engines comprising a carburetor unit provided with means for forming a primary mixture of air and fuel and a manifold associated therewith which is adapted to supply a combustible mixture to the engine intake ports, said manifold having a plurality of passages formed therein, means for delivering the primary'mixture to one of said passages, normally closed means for admitting air only to another of said passages and means for rendering said last mentioned means effective after a predetermined engine speed is reached.

11. A charge forming device for internal combustion engines comprisin a carburetor unit provided with means for orming a pri mary mixture of air and fuel and a manifold associated therewith which is adapted to supply acombustible mixture to the engine intake ports, said manifold having a plurality of passages formed therein, means for delivering the primary mixture to one of said passages, means for admitting air to said passage during operation at intermediate and high speeds and for admitting air to another of said passages only during operation at high speeds. I

12. A charge forming device for internal combustion engines comprising a carburetor unit provided with means for forming a primary mixture of air and fuel and a manifold associated therewith which is adapted to supply a combustible mixture to the engine intake ports, an air inlet for supplying air to said manifold, and a plurality of passages formed in said manifold, one of said passages being in communication with said air inlet at all times, and means adapted to effect com munication between the air inlet and another of said passages only at speeds above a pretake ports, an air inlet for supplying air to said manifold, a plurality of passages formed in said manifold, one of said passages being constantly open, a valve in the other of said passages to regulate the flow therethrough, and means for delivering the primary mixture to the constantly open passage.

14. A charge forming device for internal combustion engines comprising a carburetor unit provided with means for forming a primary mixture of air and fuel and a manifold associated therewith which is adapted to supply a combustible mixture to the engine intake ports, an air inlet for supplying air to said manifold, a plurality of air passages of dilferent size in said manifold, and means. for delivering the primary mixture to the smaller of said passages.

15. A charge forming device for internal combustion engines comprising a carburetor unit provided with meansfor forming, a primary mixture of air and fuel and a manifold associated therewith which is adapted to supp11 .a combustible mixture to the engine in ta e ports, an air inlet for supplying air to said manifold, a plurality of passages of different size in said manifold, means for delivering the primary mixture to the smaller of said passages, and means for closing the larger of said passages at all speeds below a certain predetermined speed.

16. An intake manifold for an internal combustion engine comprising a plurality of outlet branches adapted to communicate with the engine intake ports, an air inlet admitting air to said manifold, and a plurality of passages formed in said manifold, each of which communicates with said air inlet and with all of the engine ports.

17. An intake manifold for an internal combustion engine comprising a plurality of outlet branches adapted to communicate with the engine intake ports, an airiinlet'admitting air to said manifold, a plurality of passages formed in said manifold, one of said passages being constantly open and means for closing another of said passages until the engine is operating at a certain predetermined speed.

18. An intake manifold for an internal combustion engine comprising a plurality of outlet branches adapted to communicate with the engine intake ports, an air inlet admitting air to said manifold, a plurality of passages formed in said manifold, one of said passages being constantly open and a normally closed suction operated valve in another of said passages adapted to be opened when the engine is operating at a certain predetermined speed. 19. An mtake manifold for an internal combustion engine comprising a plurality of outlet branches adapted to communicate with the engine intake ports, an air inlet admitting air to said manifold and a partition in said manifold dividing it into two passages, each of which communicates with said air inlet and with all of said intake ports.

In testimony whereof I hereto aflix my signature.

FRED E. ASELTINEG

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