US1857776A - Charge forming device - Google Patents

Description

May 10, 1932- F. E. ASELTINE 1,357,775

CHARGE FORMlNG DEVICE Filed June 27, 1929 3mm QW seline e@ yam wad erating conditions.

Patented May 1'0, 1932 UNITED STATES PATENT oFFlc i FRED E. .ASELTINE OF DAYTON, OHIO, ASSIGNOR TO DELCO'PRO'DUCTS CORPORATION, OF

' DAYTON, OHIO. A CORPORATION 0F DELAWARE u CHARGE FORMING DEVICE Application led .Tune 27, 1929. vSerial No. 374,118."

take ports and in which the primary mixture Y 1s mixed with additional air under certain op- Devices of this character are disclosed in the copending application of Fred E. Aseltine and Wilford H. Teeter, VSerial No. 221,371, filed September 22, 1927.

It is the principal object of the present invention to provide a device of this character in which a minimum amount'of fuel is consumed without reducing the engine efficiency. More particularly, it; is the object of this invention to provide means for proportioning the mixture which is effective to supply a 1 relatively lean mixture during operation v throughout the normal driving range and aV somewhat richer mixture when operating l with the throttle nearly closed oit substantially wide open.

' This invention is .in the nature of an improvenient on the later application above referred to and comprises an auxiliary air inlet adapted to admit additional air to the air passage which supplies air to the secondary mixing chambers. This passage is normally closed by means of a valve which is operatedl by the primaryV throttle and is adapted to be opened when said throttle occupies an intermediate position, but is adapted to be closed when the throttle isl substantially in cloled position, or in substantially fully open position. A suction operated valve is also provided in said auxiliary air passage to regu-1 late the air flowing therethroughin accordance with the manifold vacuum, so as to vai' ri ably control the proportions' of the mixture/ as the engine suction varies. p Further objects and advantages of the presi ent invention will be apparent from the fol-y lowing 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 vertical, longitudinal section through a charge forming device constructed in accordance with the present invention and the intake port with which it is associated.

Fig. 2 is ra fragmentary, transverse, vertical' section on the line 2--2 of Fig. 1. l Fig. 3 is a fragmentary section on the line 3---3 of Fi 1.

The device disclosed comprises a main yair manifold 10, having' three outlet branches, the middle branch 12 being shown herein.

Each of these branches communicates with yone of the intake ports 14" of a multicylinder engine. The outlet branches are each provided with an attaching flange 16 for securing the manifold to the engine block inthe usual manner, anda angc 18 to 4.which the carburetor unit is secured.

The carburetor unit comprises a main housing 20, having an attaching flange 22, adapted to be secured to the fiange 18 by screws 24. An air inlet coupling 28 is secured -in position to-register with an opening in the upper wall of thehousing 20, in any suitable way and may be connected withan'air cleaner if desired. A casting 30, in vwhich the passages supplying fuel to the nozzles are formed, is secured by screws to the lower wall of hous- ,ing 20, and a sheet metal fuelbowl 32 is held tight againstan annular shoulder 34 on the housing by any suitable means. Fuel is conducted from amain source of supply to the' fuel bowl through a conduit (not shown) andl the fiow of fuel to the bowl is controlled by a float 36, operating in the usual'manner to maintain a substantially constant level of fuel therein. l u i 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 cha-mbers 40, the construction of which is briefly described hereinafter. Thefuel conduit between the fuel bowl and the nozzles comprises the vertical fuel passage 42 communicating at its upper end with the 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 to drop sufficiently to cause a temporary fuel starving of the engine unless means are provided to prevent this action. For this purpose a check valve 54 is provided iiran enlarged chamber 56 at the junction of the channels 42 and 44, and on reduction of mixing chamber suction, seats on the bottom of the chamber, preventing downward flow of fuel.

Each primary fuel nozzle is provided with a main fuel outlet 58 in the top of the nozzle and a secondary fuel outlet comprising two orifices 60 and 62 in the vertical Wall of the nozzle near the bottom of the mixing chamber. At relatively high speeds. the mixing chamber suction is sufficient to lift fuel from the main outlet as Well as from orifices 60 and 62. At idling, or low speed operation under load, however, the suction is enough lthrottle valves constitute no part of the present invention and are not disclosed herein` it to lift fuel onlv to some point between the top of the nozzle and the orifices 60 and 62,

fuel flowing from these orifices by the action of gravity under such operating conditions.` Each nozzle is provided with a restricted fuel metering orifice 63. iThe primary mixing chambers comprise the enlarged anterior ends of the 'primary mixture passages 64,

which are parallel to each other andv close together, as indicated in Fig. 2. Nhen the carburetor is attached to the manifold. these passages register with conduits which con vey the primary mixture to the secondary mixing chambers, as fully disclosed in the application above referred to. Restrictions 66 separate the primarvv mixing chambers from thepremainder of the mixture passages to reduce the velocity. ofv iiow past the fuel' nozzles' for a purposefully set ,forth in the above mentioned copending application.

A single throttle valve 68, which extends across all theprimary mixture passages, controls the flow therethrough andl is provided with grooves 70, which register with said mixture passages. This throttle is operated bv means hereinafter more fully described. The middle primary mixture passage communicates with a tube 72 fixed in the manifold branch 12. This tube constitutes one of the primarymixture conduits above referred to and conveys the primary mixture to the secondary mixing chamber located in the middle branch of the manifold.

Nearly all of the air entering the carbureation of these valves` The primary throttle ing of this valve must be retarded to prevent `is controlled by themain air valve 74, normally held against a seat 76 by a spring 78, received between the valve and a flange 80, projecting from a sleeve 82, slidably mounted on a stationary guide sleeve 84, fixed in the housing 20, and serving also as a guide for the stem 86 to which the air valve is secured. lVhen it is desired to choke the carburetor to facilitate starting of the engine, the flange 80 is adapted to be lifted by means not shown herein, but fully described in the above application, until the upper end of the sleeve 82 engages the air Valve to hold it closed. Suiiicient air to carry the starting fuel from the 80' nozzles to the intake ports is admitted through an elongated slot 90, formed ina plate 92. secured to the housing 20, as shown in Fig. l.

The valve 74 admits air to the air chamber 94 from which air flows to the primary mixture passage, through an orifice 96 in the bottom of the air chamber and to the secondary mixing chambers through a passage 98, which connects With the inlet of the manifold 9 10. A manually operable throttle 100 secured to a shaft 102, rotatably mounted in the housing and operated by means hereinafter fully described, controls the fioW of air through the passage 98.

The operating connections for .the two being sufficient for the purpose of this disclosure to describe brieflv the mode of oper- 68` is connected to the main air throttle 100 by a lost motion connection which permits a predetermined movement of the primary throttle independent of the throttle and justed so that the primary throttle is moved without accompanying movement of the air. throttle until the former reaches a position corresponding to a vehicular speed of ap-' level. On further opening of the primary throttle the air throttle is moved simultaneously therewith. i v

,On opening of one or both of the throttle .115 waves the suction in the air chamber 94 is increased and the valve 74 is opened to ad-y mit additional air and increase the quantity L of mixture. supplied to the engine. The openfluttering of the valve and to prevent admis sion of enough air to dilute the mixture. For 3: n

this purpose a dashpot is provided compris-A` j; ing a cylinder 104 formed in the casting 30 l and a piston 106 secured to the lower end of the valve stem- 86 by any` suitable means. This da'shpot is of conventional form and its specific construction is not material to the present invention.

In order to accomplish the object of this o5' n is capable of adiustment. It is generally ad- 11o proximately 15-20 miles per hour on-the-.

b i 116 so that the valve closes this bore when invention the main liousing20 is cast with an external' fiat surface 108 as shown in 'F ig. 3. Secured tothis flat surface by screws 110 is a small casting 112 havinga passage 114 formed therein for supplying additional air to the secondary air passage. Abore '116 in the casting 112 communicates with a larger orifice 118 in the Wall of the main housing immediately in front ofthe air throttle 100 to permitthe flow of air from the passage 114 into the secondary air passage as described. The passage 114 is normally closedby a plate 120 pivoted on a pin 122 secured in any suitable manner in the casting 112. Y The plate is provided with a slot 124 which ismoved into registry with the passage 114 when the prinary throttle is moved to intermediate positions, but is moved out of registry with said passage 114 before the throttle reachesV its fully opened position.

In order to move the plate 120 in the manner described 'an operating arm 126 is secured to a hub 128 pinned to the spindle 130 projecting from the primary throttle, sons to rotate therewith. The arm 126 has a' slot 132 in its free end which engages a pin 134 projecting laterally from the lower 4end of the plate 120 so as to rock the plate on its pivot when the arm is moved e `with the throttle. On counterclockwise or opening movement of the throttle the plate .120 will las . closes the passage 114 but the flow of air be rotated in a clockwise direction from the V position shown .in Fig. `1 to move the slot into engagement with passage 114 and` continued opening movementof the throttle will move said slotv beyond the passagef114 to again close said passage as the primary throttle reaches its fully opened position.L- A spring 136 surrounds the pin 122 between the plate 120 and a collar 138 onthe pin 122 so as to .press the plate 120 into engagement with the casting 112,. preventing material leakage of air into the passage 114 when the plate 120 is in position tovclose said passage.

As described above the plate 120 opens and through said passagevwhen the latter'is open is controlled by a suction operatedvalve 140 which 'is positioned Within, the orifice 118 and is'of'somewhat larger size than the bore in its closed position as shown in Fig. 3. The

valve is secured to the end ofa valve stem 142 slidable in a bore in the casting 112 and normally heldin closed position by a spring 144 surrounding the valve stem and received bei tween' the casting 112'and 'an enlarged head ses 146 on the valve. Obviously, theY position of this valve Will vary in accordance with variations in the suction between the air throttle and thefintake port and will va'riably control the" richness of the mixture in accordance With such'suction The secondary mixing chambers comprise venturi tubes 15.0 which are positioned in the outletfbranchesofthe lmanifold adjacent the outlet ends ofthe primary mixture conduits.

.',lheseu venturitubes `are identical and keach isprovided with an` externalA rib 152 adapted tobe clamped between shoulders154 and v156 on the manifold and the engine blockrespec-- tively *ivhen the device is assembled'. These tubes accelerate the flovv` of air past'tlie deincreasing the velocit-y of flow rtherethrough as fully s et forth inthe earlier oftlie above mentioned applications. While the form of embodiment of thepresent invention as: hereiirdis'closed, constitutes a preferred form, itis to be understood that Vother forms might be adopted,all coming Within the scope of the claims which follow. WVliat is .claimed isfas follows:

,livery ends of the primary' 'mixture conduits, .y

1.y A charge-ffori'ning device for` internal Y combustion engines 'comprising a `secondary mixing chamber, a primary mixture 'passage delivering a primary mixture lof fuel and air thereto, means for supplying fuel and air to lsii said mixture iiassage, a primary throttle rege ulating the loivtherethrough,l a secondary air vpassage supplying air to said secondary mixing` chamber, meansV for regulating the mixture proportions comprising an auxiliary air passage communicating directly with the atmosphere and supplying.;l air to thesecondary air passage and means operated the primary throttle for controlling Vthe flow of air through said passage.

2. A charge forming device for internal io'o combustion engines comprising aA secondary mixing chamber, a primary mixturepas'sage delivering aprimary mixture' of fuel and air thereto, means for supplying fuel and air to said mixture passage, apriinary throttle regulating the flowl therethrough, y aV secondary air passage supplying air to the sf-condai-y mixing chamber means for regulating the mixture proportions comprising an auxiliary air passage communicating directly Withthc ondary air passage andfnieans operated by they-primary throttle for regulating the flow of air through said Vpassageivhich,is effective p to permit a'flow therethrough only when the throttle is partially opened. p

3. kA Acharge' forming device for internal combustion engines comprising a secondary' 'mixing chamber, a primary mixture passage delivering a primary mixture of fuel and v air thereto, means for supplying fuel and air to said mixture passage, a primary throttle regulating the flow therethrough. a secondary air passage for supplying air to the secondary niixinglchamber, means for regulating the 125' atmosphere and supplying air to the sec- 1107 ing its opening movement to open said valve and effective after a predetermined movement passage, means for supplying fuel and air a primary mixture o thereto, a throttle regulating the flow through said passage, a secondary air passage supplying additional air to the mixture passage means for regulating the proportions of fuel and air inthe mixture comprising an auxils iary passage communicating with the atmosphere and supplying air to the secondary air passage, and a plurality of means for controlling the flow through said auxiliary pas sage. l

5'. A charge forming ,device for internal combustion engines comprsing a mixture passage, means for supplying fuel and air thereto, a throttle regulating the flow through said passage, a secondary air passage supplying additional air to the mixture passage means for regulating the proportions of fuel and air in the mixture comprising an auxiliary passage'communicating with the atmosphere and supplying air to the secondary air passage,`means operated by the throttle for rendering said auxiliary passage effective and means operated by the suction of the en.- gine'for controll-ing the flow through said passage.

'6. A. charge forming device for internal .vf-.combustion engines comprising a plurality of secondary mixing chambers, a plurality of primary mixture assages Vfor supplying E) fuel and air thereto, a primary throttle valve controlling the flow through all of the primary mixture passages, means for regulating the proportions of ucl and air in the ,mixture comprising an auxiliary air passage adapted' to supply air to the mixture formed Y in all of said primary mixture passages and means operated by theV primary throttle for controlling the flow through said passage. Y 7. A charge forming device for internal Vcombustion engines comprising a plurality of secondary mixing chambers, a plurality of primary mixture passages'for supplying a primary mixturev of fuelr 'and air thereto, a primary throttle'valve controlling the loiv Athrough all ofthe primary mixture passages,

means for regulating the proportions of fuel and air in the mixture comprising an auxiliary air passage adapted to supply air to the mixture formed in all of; said primary mixture passages, and a plurality of means for controlling the iiow through said assage, one.

of said means being operated by t e manifold vacuum and the other by the primary throttle.

8. A charge forming device for internal combustion engines comprising a plurality of secondary mixingchambers, a plurality of primary mixture passages for supplying av a secondar air passage supplying air to al primary throttle valve controllingthe How throughlall ofthe primaryfmixture passages, a secondary air passage supplying air to all of said secondary mixing chambers, and means for regulating the mixture proportions comprising an auxiliary air passage communicating with the atmosphereand adapted to admit air to the secondary air passage under certain operating conditions. 9. A charge forming device for internal combustion engines comprising a. plurality of secondary mixing chambers a plurality 'of primary mixture passages or supplying a primary mixture of fuel and air thereto, a primary throttle valve controlling the How through all of the primary mixture passages,

a secondary air passage supplying air to all c of said secondary mixlng chambers, an air throttle in said passage, means for regulating the mixture proportions comprising an auxiliary air Ypassage admitting air to said secondary air passage posterior to the throttle therein. i

' 10. A charge forming device for internal combustion engines comprising a plurality of secondary mixing chambers, a plurality of primary mixture passages for supplying a primary mixture of fuel and air thereto, a primary throttle valve controlling the iiow through all of the primary mixture passages,

said secon ary mixing chambers, an air throttle in said passage, means for'regulating the mixture proportions comprising anv auxiliary air passage admitting air to said secondary f air passage posterior to the throttle therein, and means operated bythe primary throttle for controlling the flow through said passage. v

11. A charge forming devicefor internal combustion engines comprising a secondary mixing chamber, a. primary mixture passage delivering a primary mixture 'of fuel and air thereto, means for supplying-fuel and,v air to said mixture passage, a primary throttle regulating the flow therethrough, a secondary air passage supplying air to the' secondary mixing chamber, means for regulating the mixture proportions comprising an auxiliary air passage admitting air to the secondary air passage, and means for regulating `the flowV through said passage in accordance Witlvvari- I ations in engine suction. In' testlmony whereof nature.

- E. ASELTINE.:`

I heretoairix my sig;

primary mixture of fuel and air thereto, a,

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