US1913139A - Charge forming device - Google Patents

Description

June 6, 1933. F, E ASELTlNE 1,913,139

CHARGE FORM'I NG DEVICE Filed June 17, 1929 :f :.-w/ \\\\\\\\\\\\V /4 i ig/sllum z| 'i /lml m 'Patented Junel 6, 1933 UNITED STATES FRED E. ASELTINE, OF DAYTON, OHIO, ASSIGNOR TO DELCO PRODUCTS CORPORATION, OF- DAYTON, OHIO, A CORPORATION OF DELAWARE CHARGE FORMING DEVICE Application led June 17, 1929. Serial No. 373,462.

This invention relates to charge forming devices for internal combustion engines and more particularly to the type of charge forming device which comprises a plurality of primary mixing chambers, one for each engine intake port, which cooperate respectively with a plurality of secondary mixing chambers located adjacent said ports and receiving a primary mixture of fuel and air from pipes connected with the primary mixing chambers, while receiving air when required, through an air manifold having a single air inlet for supplying air to all of the said secondary mixing chambers.

An example of a charge forming device of this character is disclosed in the copending application of Fred E. Aseltinev and Wilford H. Teeter, Serial No. 221,371, filed September 22, 1927. y

It is the principal object of this invention` tol Aprovide improved means for controlling 4the proportions of fuel and air in the mixture and more particularly to provide means for supplying a mixture on all opening movements of the throttle which is rich enough in fuel content to supply the necessary power for smooth and rapid acceleration.

According to the present invention, .this object is accomplished by providing a common operating mechanism Vfor the air throttle which controls the admission of air tothe main air manifold through the secondary air' passage, and the primary throttle, but which is constructedto delay the openingof the air throttle relative to the rimary throttleon any openinrrmovement o the latter, so that whenever the primary throttle is opened abrief interval of time elapses before the air throttle makes a corresponding opening movement. To this end a resilient operating connection is provided between the operating arm for the primary throttle and the air throttle, and a suction operated, collapsible bellows is connected to the air throttle which tends to hold the air throttle closed at all times and does not permit said throttle to open until the manifold vacuum falls subsequent to any opening movement of the primary throttle. l f` Further objects and advantages of the pres.-

ent invention will be apparent from the foll,

lowing description, reference being had to the accompanying drawing wherein a preferred embodiment of one form of the present invention is clearly shown.

1n the drawing:

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 a fragmentary, transverse, vertical section on thc line 2-2 of Fig. 1.

Fig. is a fragmentary side elevation of the main carburetor unit.

Fig. 4 is a fragmentary side elevation of the main carburetor unit viewed from a direction opposite to Fig. 3.

The device disclosed comprises a main air manifold 10, having three outlet branches, the middle branch 12 being shown herein. Each of these branches communicates with one of the intake ports 14 of'a multicylinder engine. The outlet branches are each provided with an attaching iange 16 for se? curing themanifold to the engine block in the usual manner, and a fiange 18^ to 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 flange 18 by screws 24. An air inlet coupling 28 is secured in position to register with an opening in the upp'er wall of the housing 20, in any suitable way and may be connected with an air cleaner if desired. A casting 30, in which the passages supplying fuel to thenozzles are formed, is secured by screws to thelower wall of housing 120,- 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 herein) and the fiow of fuel to the bowl is controlled by a lioat36, operating in the usual manner to maintain'a substantial level of fuel therein.

Fuel flows from the bowl 32 to a plurality joffprimary fuel nozzles 38, one of which is located in each of the primary mixing cham- :bers 40, the constructlon of which is briefly described hereinafter. 'llhe fuel 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 `orrifice 48 and at high speeds additional fuel is admitted through an orifice 50 controlled by a valve 52, operated in the manner set forth in the above mentioned application. rl`his operating means forms no part of the present invention and need not be described further herein.

Fuel is lifted from the fuel bowl through 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 mixing chamber suction which might permit the fuel column 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 in an 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 0f 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 to lift fuel only to some point between the top of the nozzle and the orifices 60 and 62, fuel fiowing from these orifices by the action of gravity under such operating conditions. Each nozzle is provided with a restricted fuel metering orifice 63. The primary mixing chambers comprise the enlarged anterioi` ends of the primary mixture passa es 64, which are parallel to each other an close together, as indicated in Fig. 2. When the carburetor is attached to the manifold, these passages register with conduits which convey the primary mixture to the secondary mixing chambers, as fully disclosed in the application above referred to. 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 a purpose fully set forth in the above mentioned copending application.

A single throttle valve 68, which extends across all the primary mixture passages, controls the flow therethrough and is provided which register with said with grooves 70,

This throttle is operated mixture passages.

Lerares by means hereinafter more fully described. rlhe middle primary mixture passage communicates with a tube 72 fixed in the manifold branch 12. This tube constitutes one of the primary mixture 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 carburetor flows through the inlet coupling 28 and is controlled by the main air valve 74,

normally held against a seat 76 by a spring 78, received between the valve and a fiange 80, projecting from a sleeve 82, slidably mounted on a stationery guide sleeve 84, fixed in the housing 20, and servingI also as a guide for the stem 86 to which the air valve is secured. When 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. Sufficient air to carry the starting fuel from the nozzles to the intake ports is admitted through an elongated slot 90, formed in a plate 92, secured to the housing 20, as shown in Fig. 1. The valve 74 admits airto the air chamber 94 fromy which air Hows to the primary vmixture passage,

lthrough an orifice 96 in the bottom of the air chamber and to the secondary mixingl chambers through a passage 98, which connects with the inlet of the manifold 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 flow of air through the passage 98.

On opening of either or both of the throttles 68 and 100, the suction in the air chamber is increased and the air valve is opened against the tension of its spring to admit additional air` and increase the quantity of mixture supplied to the engine. The opening of the valve must be retarded to some extent, however, to prevent admission of sufficient air to lean the mixture. To accomlplish this result and to prevent fluttering of the valve, a dashpot is provided comprising a cylinder 104 formed in the casting 30 and a piston 106 secured to the valve stem 86 by means of a nut 108, or in any other desirable manner. The dashpot is adapted to he filled with liquid fuel through the medium of a check valve (not shown) in the bottom of thedashpot' or in any other suitable way. This, dashpot is of conventional form and its specific construction constitutes no part of the present invention.

According to ths invention, the primary throttle Ais operated by means of an arm 110 adjustably secured by means of a set screw or in any other suitable way to a spindle 112 projecting from the throttle. This arm teniamo is adapted to be connected to some suitable operating connection extending to a point convenient to the operator of the vehicle. Projecting from arm and integral therewith, is another arm 114,`to which a rod 116 is pivotally Connected at its free end. A lined collar 118 is secured to the rod at a point intermediate-its length and a collar 120 is slidable on said rod between the collar 118 and the enlarged head 122 on the end ot' the rod, a coil spring 124 being received between the collar 120 and the head 122 and operating to hold the collar 120 against the collar 118 when the parts are statonary, A djustably secured to one end of the shaft 102, outside of the housing 20, is an arm 126, which is forked at its tree end and pivotally engages pins 128 projecting from the collar 120. 1t will be clear that a counterclockwise movement of' the operating arm 110 will move the rod 116 downwardly and compressing the spring 124, will move the arm 126 downwardly to compress the spring 124 and open the a`r throttle 100 when the pressure of said spring on the collar 120 is sufficient to overcome the resistance to movement ofthe said throttle valve.

' lln order to oppose any opening movement of said air throttle and to insure an initial opening movement of the primary throttle before the air throttle begns to open whenever the primary throttle is opened, a bellows 130 is provided. Integral with the plate forming the bottom of the bellows is the nipple 132, which is screwed into the wall of the passage 98 and has a suction passage 134 therein, which communicates the mamfold vacuum to the interior of the bellows.

r1`he plate 136, forming the top of the bel-` lows, has a lug 138 projecting therefrom and secured to said lug is a bent rod 140, which extends horizontally and downwardly, as indicated in Fig. 4. rthis rod is provided with fixed and movable collars 142 and 144 respectively, and the coil spring 146 is received around the rod between the movable collar 144 and the enlarged head 148, on the end of the rod. djustably secured to the end of the shaft 102 opiposite to that on which the arm 126 is secured, is an arm 15@ forked at the end and adapted to pivotally engage pins 152, projecting from the movable collar 144. A spring 154 is received within the bellows and when the engine .is not in operation, the spring is adapted to expand the bellows so that the parts are it the position shown in Fig. 4.

'llhe above described mechanism operates in the following manner: When thel engine is idling or operating under load at very low speed, with the throttles in substantially closed position, the manifold vacuum at points posterior to the throttle 100 is very high, and the bellows is contracted against mary throttle to increase the engine speed will pull the rod 116 downwardly co1npressing the spring 124 and increasingits pressure on the arm 126 tending to open the throt tle 100, but the latter is held closed by the bellows, as above described. However, the

opening of the primary throttle reduces the vacuum at all points posterior tothe throttle 100 and the bellows is permitted to en pand, the rate of expansion being determined by the size ot the passageway 134 which allows air to enter the bellows from the passage 98 when the manit'old suction falls.. 131s the bellows expands, the spring 124 is ed'ective to move the arm 126 in a counterclocltwise direction and open the throttle 100 until the pressure of the spring is balanced by the etect of the bellows. 1t will be obvious from the above that before any opening movement of the throttle 100 can take place following an opening movement of. the primary throttle, the bellows must expand to a degree determined by the opening ot the primary throttle and since air is admitted to the bellows through the passage 134 relatively slowly, there must be an appreciable delay in the opening of said throttle 100 relative to the primary throttle on all opening movements of the latter. 1t will be obvious that the spring 124 may be of any desired strength so as to permit whatever opening ot the primary throttle may be desired before any opening of the air throttle can take place. Preferably the spring is of such strength that the primary throttle can be opened sufficiently to operate the vehicle at a speed of substantially 20-25 miles per hour on a level before the spring pressure is sucient to overcome the resistance of the bellows to ellect any opening of the air throttle.

r1`he mechanism above described, is not ettective to delay closing movements of the throttle 100, however, as the fixed collar 118 engages the collar 120, when the primary throttle is moved towards closed position so as to close the throttle 100 positively and simultaneously with the movement ot the primary throttle.

A secondary mixing chamber is associated with each outlet branch of the manifold, only one of such chambers being shown herein. Each secondary mixing chamber comprises a Venturi tube 156 having an external rib 158 which is clamped between the shoulders 160 and 162 on the manifold and the engine block respectively, when the device is assembled. r1`he Venturi tube is so positioned that the outlet ot the primary mixture conduit associated therewith terminates at the point of greatest suction therein and serves to increase the suction edective at the end ot its l :l throttle relative to the primary throttle.

associated primary mixture conduits. rlhese Venturi tubes constitute no part of the presn ent invention but function4 in a manner fully set forth in the above mentioned copending application. 4

While the form of embodiment of the present. invention as herein disclosed, constitutes l a preferred form, it is to be understood that other forms might Ibe adopted, all coming within the scope ofthe claims which follow.

'What is claimed is as follows: 1. A charge forming device for interna-l combustion engines comprising a mixing combustion engines comprising a. mixing chamber, means for supplying fuel and air thereto, Aa primary throttle, a secondary air passagehaving an air throttle therein, operating means for the primary throttle, a resilient operating connection between the primary throttle and the air throttle, and means controlled by the suction of the engine for delaying the opening movements of the air 3. A charge forming device for internal combustion engines comprising a mixing chamber, means for supplying fuel and air thereto, a primary throttle, a secondary air passage having an air throttle therein, operating means for the primary throttle, means 'for operating the secondary throttle by said primary throttle,'means controled by the s uction of the engine for delaying the opening movements of the air throttle relative to the ,primary throttle.

44. A charge forming device. for internal combustion. engines comprising a mixing chamber, means for supplying fuel and air thereto, a primary throttle, a secondary air passage having an airthrottle therein,- operating means for the primary throttle, means for operating the secondary throttle by said primary throttle, means controlled by the suction of the engine for delaying the opening movementsof the air throttle rela-tive to the primary throttle on all opening move ments of the latter.

5. A charge forming device for internal combustion engines comprising a mixing chamber, means for supplying fuel and air thereto, a secondary air passage having an air throttle therein, operating means for the iimary throttle, means connecting the air throttle to the primary throttle for operation maaien therewith and constructed to permit an independent initial opening movement of the primary throttle, and means controlled by the engine suction for preventing opening of said air throttle during .said initial movement of the primary throttle.

6. A. charge forming device for internal combustion engines comprising a mixing chamber, means for supplying fuel and air thereto, a secondary air passage having an air throttle therein, operating means for the primary throttle, means for operating the two throttles simultaneously and constructed to permit independent initial opening movement of the primary throttle, and means controlled by the suction of the engine for preventing opening of the air throttle during the initial opening movement of the primary throttle and for delaying the opening of the air throttle on any other opening movement of the primary throttle.

A charge forming device for internal `combustion engines comprising a mixing chamber, means for supplying fuel and air thereto, a secondary air passage having an air throttle therein, operating means for the primary throttle, resilient means connecting the two throttles for simultaneous operation and constructed to permit independent openinginovement of the primary throttle, and means controlled by the suction of the engine for preventing opening of the air throttle during the initial opening movement of the primary throttle and delaying opening of the air throttle during any other opening movement of the primary throttle until the force exerted by the resilient operating connection overcomes the effect of said last mentioned means.

8.n A charge forming device for internal combustion engines comprising a mixing chamber, means for supplyingfuel and air thereto,'a primary throttle, a secondary air passage having an air throttle therein, means for operating said primary throttle and said air throttle, and a suction responsive member for resisting the opening movements of said air throttle.

9. A charge forming device for internal combustion engines comprising a mixing chamber, means `for supplying fuel and air thereto, a primary throttle, a secondary air passage having an air throttle therein, means for operating said primary throttle and said air throttle, a suction responsive member for resisting the opening movements of said air throttle, and a passage connecting the suction i responsive member with the secondary air passage. l

l0. A charge forming device for internal combustion engines comprising a mixing chamber, means for supplying fuel and air thereto, a primary throttle, a secondary air passage having an air throttle therein, means for operating said primary throttle and said air throttle, a suction responsive member for resisting the opening movements of said air throttle,` and a passage communicating the manifold vacuum to the suction responsive member.

11. A charge forming device for internal combustion engines comprising a mixing chamber, means for supplying fuel and air thereto, a primary throttle, a secondary air passage having an air throttle therein, means for operating said primary throttle and said air throttle, a suction responsive member for resisting the opening movements of said air throttle and a suction passage connecting the suction responsive member with the secondary airpassage posterior to said air throttle.

12. A charge forming device for internal combustion engines comprising a plurality of secondary mixing chambers, a plurality of primary carburetors adapted to deliver a primary mixture of fuel and air to said secondary mixing chambers, mixture passages for conveying the primary mixture to said secondary mixing chambers, a single primary throttle for controlling the flow through all of said primary mixture passages, a secondary air passage for admitting air to all of said secondary mixing chambers, an air throttle in said passage, means for operating said throttles constructed to permit a limited opening movement of the primary throttle independently of the air throttle and a suction responsive member for holding said air throttle closed during said initial opening movement of the primary throttle and for throttle therein, operating means `for said primary throttle, a resilient operating connection between the primary throttle and the air throttle and means controlled by the suction within the secondary air passage for delaying the opening movements of the air throttle relative to the primary throttle.

15. A charge forming device for interna-l combustion engines having in combination, a secondary mixing chamber, a primary mixture passage adapted to deliver a primary mixture of fuel and air thereto, means for supplying fuel and air to said primary mixture passage, a primary throttle controlling the How of mixture therethrough, a secondary air passage supplying air to said secondary mixing chamber and having an air throttle therein, operating means for said primary throttle, a resilient operating connection between the primary throttle and the air throttle, and means controlled by the suction within the secondary air passage on the engine side ofthe throttle therein for delaying the opening movements of the air throttle relative to the primary throttle.

lin testimony whereof ll hereto a'x my signature.

' FRED E. ASELTINE.

delaying all other opening movements of the primary throttle, a resilient operating connection betweenv the primary throttle and the air throttle and means controlled by the suction of the engine for delaying the opening movements of the air throttle relative to the primary throttle.

v14. A charge forming device for internal combustion engines having in combination,

a secondary mixing chamber', a primary mixture passage adapted to deliver a primary mixture of fuel and air thereto, means for supplying fuel and air to said primary mixture passage, a primary throttle controlling the flow of mixture therethrough, a secondary air passage supplying air to said secondary mixing chamber and having an air

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