US1909035A - Charge forming device - Google Patents

Description

Jerome 1. Jason 8., wnmw ajf Patented May 16, 1933;

' NITED STATES PATENT orrica 3130!! I. A8808, 0! DAYTOILOHIO, ASBIGN'OB TO DELCQ PRODUCTS CORPORATION,

or nan-on, care, a coaroaa'non or nmwaaa cannon romrmo DEVICE 7 Application fled June 19, 1989. Serial Il'o. 370,191.

This invention relates to charge forming devices for internal combustion engines and most particularly to the type of charge forming device which comprises a plurality of primar carburetors, one for. each intake port 0 the engine, which cooperate respectively with a plurality of secondary mixing chambers located adjacent'the engine intake ports, and which receive primary mixture rom pipesconnected with the primary mix- ;ing chamber, while receivingadditional air under certain operating conditions through branches of an air manifold having a single 7 air inlet passage controlled. by a singlefmain 1B. i

air throttle.

Examples of charge forming devices of this character areshown in the copending application ofv Fred E. Aseltine and WiI- ford H. Teeter, Serial No. 221,371, filed September 22,192? which matured to Patent 1,819,495 granted Aug. 18, 1931 and Wilford a H. Teeter, Serial No. 312,509, filed October '8, 1928, which matured to Patent 1,849,499

granted Feb. 23,1932 and the present invention constitutes an improvement on the device disclosed'in the later filed application.

The device disclosed in the aboveapplication of Wilford H. Teeter involves a departure from the construction of earlier devices of this character. This chan structioncomprises theprovision 0 separate in conair inlets forthe primary carburetors and secondary mixing chambers, controlled by separate spring closed valves, the purpose of this change in construction being to improve the mixture proportioningunder certain operating conditions, particularly during acceleration and on operation at-low engine speeds. In the Teeter constructionthe admission of air to the primary carburetor isentirely automatically controlled being regulated solely by the suction of the engine and the air valve spring itself.

The primary purpose of the present invention is to provide means to control the admission of air to the. primary mixing.

chambers, in such a manner that the devicev is effective to supply a mixture of more nearly ideal proportions,particularly during the ing the pressurev of said spring onthe valve as the throttle opens, after said throttle has made a predetermined amount of movement,

said means being constructed so as to have no effect on the spring during the first part ofthe opening movement of said throttle.

Further objects and advantages of .the

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

In the drawing:

Fig. 1 is avertical lon 'tudinal section through a charge forming evice embodying the present invention and one of the associated engine intake-ports.

Fig. 2 is a fragmentary transverse section onthe line 2-2 of Fig. 1.

Fig. 3 is a fragmentary side elevation showing the throttle operating connections.

Fig. 4 is a fra mentary front elevation viewed from the le in Fig. 1.

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. These outlet branchesare each provided with an attaching flange 16 for securing the manifold to the enginebloc'k in the usual manner. Adjacent the inlet of the manifold is rovided a flan e 18 to which the main car uretor unit is a apted to be attached, as shown in ing'20 having an attaching flange 22, adapted to be secured to the flange 18'by screws 24.

.An air inlet horn 28 is securedinposition to register with an opening in the upper wall of the housing 20 in any suitable way. ..A casting 30, having certain dash ot chambers and fuel passages formed therein, is secured by screws to the lower wall of the housing 20 and a sheet metal fuel bowl 32 is held tight against a shoulder 34 on said housing by any suitable means. Fuel is conducted from a main source of su ply to the fuel bowl through a conduit, not shown herein, and the flow 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. 7

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 cham-.

bers 40, the construction of which is briefly described hereinafter. The fuel conduit between the fuel bowl and the nozzles comprises a vertical fuel passa e 42 communicating at its upper end with a orizont-al fuel canal 44, which connects with each of the nozzles 38 through orifices 46. Fuel is admitted from the fuel bowl to passage 42 at all speeds through a fixed metering orifice 48 and at high speeds additional fuel is admitted through an orifice 50 controlled by a valve 52 in the manner set forth in the above mentioned applications.

Fuel is lifted from the fuel bowl throu h the above described fuel passages and nozzfias 38 to the mixing chambers 40 b the suction therein. Closing movements 0 the throttle cause a reduction in mixing chamber suction, which might permit the fuel column to drop sufliciently to cause a temporary fuel starving of the engine unless means were provided to prevent such action. For this purpose a check valve 54 is provided in an enlarged chamber 56 at the junction of channels 42 and 44, and on reduction of mixing chamber suction seats on the bottom of this chamber, preventing downward flow of fuel. 1

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 hi h speeds the mixing chamber suction is su cient to lift fuel from the main fuel outlet as well as from the holes 60 and 62. At idling and low speed operation under load, however, the suction is enough to lift fuel only to some point between the top of the nozzle and orifices 60 and 62, fuel then flowing from these orifices only by action of gravity. Each nozzle is provided with a restricted fuel metering orifice 63. The primary mixing chambers 40 comprise the enlarged anterior ends of primary mixture passages 64, which are parallel to each other and close together, as indicated in Fig. 2, and when the carburetor is attached to the manifold, these passages register with conduits which convey the primary mixture to the secondary mixing chambers, as full disclosed in the copending application re erred to. Each primary mixture passage is provided with a restriction 65 immediately posterior to the enlargements 64, for the purpose of reducing the velocity of flow past the uel nozzles.

A single throttle valve 66, which extends across all the primary mixture passages, con trols the flow therethrough and is provided with grooves 68 which register with said mixture passages. This throttle is operated by means shown in Fig. 4, and is briefly described hereinafter. The middle primary mixturepassage connects with a tube 70 fixed in the manifold branch 12, which conveys the primary mixture to the secondary mixing chamber in that manifold branch.

According to the present invention air is admitted to the primary mixing chambers by a primary air passage 72, which supplies air directly to a primary air chamber 74 and is controlled by a valve 76 which will be more fully. described hereinafter. The air chamber 74 is formed within the main housing 20 and is large enough to communicate with all the primary mixing chambers. The valve 76 is adjustably secured in any desirable manner, as by means of nuts 78 to the inner end of a valve stem 80, slidably mourted in a short sleeve 82 connected by a spider 84 to a fitting 86 screwed into the housing 20 as in dicated in Fig. 1. The valve is normally held in closed position by a spring 88, surrounding the valve stem and receive between a knurled head 90 on the outer end of said stem and a collar 92 slidable on the stem and adapted to be moved by means later described to compress the spring-88 and increase the re- Sistance said spring offers to opening movement of the valve. As the throttle 66 is opened the valve 7 6 is opened against the pressure of spring 88 to supply air to all the primary mixture (passages.

Air is supplie to the secondary mixing chambers through the inlet horn 28 and is controlled by a valve 94, hereinafter designated the main or secondary air valve, which is normally held against a seat 96 by a sprin 98 which is stron er than the spring 88. Thls spring is receive between thevalve and a flange 100 projecting from a sleeve 102 slidably mounted on a stationary guide sleeve 104, fixed in the housing 20, and serving as a guide for the stem 105 to the upper end of which the valve 94 is secured.

When it is-desired to choke the carburetor to start the engine the flange 100 is adapted to be lifted by means not shown herein but fully described in the copending applications referred to, to bring the upper end of the sleeve 102 into enga ement with the valve 94 to hold it closed. uflicient air to carry the starting fuel from the nozzles to the intake ports is admitted by the primary air valve 76.

The main air valve admits air directly to a main air chamber 106 formed inthe main housing above the primary air chamber 74 and separated therefrom 108. ir flows from this manifold 10. A manually operable air throt-.

tle 112 secured to a shaft 114 rotatably mount-- ed in the housing 20, controls the flow of air through the passage 110, said valve bein operatedfrom the primary throttle throng the medium of connections which will now.

be very briefly described. These operating.

connections are fully described inthe earlier copending cases above referred to but it is suflicient for the urposes of the present dis closure to statet at the. primary throttle is operated by means of warm 116'secured in any desirable manner to a spindle 118 projecting from one endof the throttle, and ada ted 1 to be connected at its free end to some orm of connection extending to a point convenient to the operator of the vehicle. The operating armis connected by means of-a lost motion connection, indicated'inits entirety by the reference number 120, to an arm 122 secured v to one end of the shaft 114. Thisconstruction permits a limited movement of the primary throttle independent of the air throttle 112,.enablingthe primary throttle to be partially opened while the air throttle remains completely closed. -The lost motion connection is capable of adjustment and is enerally adjusted so that only the primary t rottle is opened, whilethe vehicle on which the car buretor is used is running at speeds below a speed of approximately 15-20 miles per hour on a level. Atthis speed the-throttle 1 12 begins to open and at all higher speeds the two throttles move simultaneously.

Toprevent openingof the valve 94 sufliciently to lean the mixture, and also to prevent fluttering of said valve a dash pot isv provided, comprising a piston 124 secured to the lower end 'ofthe valve stem 105, slidably received in a cylinder 130 formed in thecasting 30 and adapted to. be filled with fuel from the fuel bowl 32, a checkvalve (not shown) being providedin the bottom of the dashpot; This dash pot is'of conventional form and the details of construction hereof constitute no part of the present invention.

As previously stated the spring 88 which I holds the valve 76-closed is relatively weak by comparison with the spring of the main a1r valve. This construction is provided to I accomplish two results, as fully ,ex lained in application Serial No. 312,509. 1rst it oposes relatively little resistance to the .openmg of valve 7, 6 so that even at low speeds the valve opens ,-to a considerable extent admitting suflic ient air to maintaina relatively low suction at the jets so as to form a relatively lean mixture, thus .correctin a tend-. ency noticeable in earlier devices of t is charby a partition wall am er to the secondar mixing chambers throu h a passage 1 110 w ich connects with the in et of .the air suction'is determined by 94. Accordingly the'dlfierence between the acter anddue to the relativelyhigh suction at the fuel jets as determined by the stronger main air valve spring, to form a mixture which is too rich in the low speed range. Second, by providing a weakspring on'the valve 76, the pressure .in the primary air chamber 7 4 .is maintained higher than would be possible if the chamber were supplied with air from the mainchamber .106 in which the the-main air valve pressure in chamber74 and thatat the osterior ends of the primary mixture con uits isreater and'the velocity of flow through suc conduits is greater than would be possible if the suction in chamber 7 4 were determined by the stronger main air valve spring. This construction produces improved acceleration because the time interval necessary for the rich primary mixture to reach the secondary mixing chambers on any opening movement ofthe throttle .isreduced, andmore nearly approaches the time required-for air to flow from the chamber 106 to said secondary mixing chambers, whereby theincreased supply of rich primary mixture and increased uantity of air resulting from theopening of t 1e. throttle reach the secondarymixing chambers substantially simultaneously.

The use of the relatively, weak spring on the primary air valve to secure the advantages above referred to, results intoo low a suction at the fuel jets at hi her engine speeds, or during operation un er heavy load at low speed wit open throttle. This results in the formation of. too lean a mixture for satisfactory o eration under the conditions referred to. o avoid this difficulty means are provided to increase the pressure of the spring tending to hold the valve closed as the throttle I is opened. This means comprises an angular operating arm 140 pivoted on ascrew 142 screwed into a lug 144 projecting from the housing 20 and integral therewith. The free end of the arm 140 is bifurcated to formtwo short arms 146 as shown in Fig. 4. The valve stem is received between the arms 146,

which liebetween the collar 82 andthe spider I 84. Pivotally connected to the arm 1'40 bya pin 148, positioned at a point intermediate the length of the arm, is a link 150, connected the means for increasing the resistance of the spring 88 to opening of the valve not only overcomes the tendency to form a too lean mixture at high speeds but aids the operation during the acceleration period as we l. The delay in opening of the valve 76 relative to the throttle results in a further temporary increase in suction at the jets during the acceleration period which will result in a temporary enrichment of the mixture during this period which is necessary to give the desired power for smooth acceleration.

Each secondary mixing chamber comprises a Venturi tube 160, positioned in the outlet of each branch of the manifold and surrounding the outlet end of the primary mixture conduit therein. The venturi is provided with an external rib 162, which is clamped between shoulders 164 and 166, on

the manifold and the engine block respectively, when the device is assembled. These Venturi tubes increase the velocity of flow past the ends and increase the velocity of flow therethrough for a purpose fully set forth in the earlier application above referred to.

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

What is claimed is as follows:

1. A charge forming device for internal combustion engines comprising a. primary mixing chamber, means for suppl ing fuel and air thereto, a throttle, a secon ary mixing chamberinto which the primary mixing chamber delivers and relatively remote from the primary mining chamber, separate suction operated means for COIItIOllIII the ad rs, said I mission of air to said mixing cham means being responsive to different degrees of suction, and means for variably andauto-v matically regulating the degree of suction necessary to operate the air admission means for the primary mixing chamber, during operation of the engine under varying operating conditions.

2. A charge forming device for internal combustion engines comprising a primary mixing chamber, means for suppl ing fuel and air thereto, a throttle, a secon ary mixing chamber into which the primary mixing chamber delivers and relatively remote from the primary mixing chamber, a valve controlling the admission of air to the primary mixing chamber and adapted to admit air thereto at all times when the engine is running, a valve controlling the admission of air to the secondary mixing chamber during only a part of the engine operation, and means for automatically and variably controlling the opening movement of said first mentioned valve during operation of the engine under varying operating conditions. i

3. A charge forming device for internal combustion engines comprising a primary mixing chamber, means for supplying fuel and air thereto, a throttle, a secondary mixing chamber into which the primary mixing chamber delivers and relatively remote from the primary mixing chamber, a valve controlling theadmission of air to the primary mixing chamber and adapted to admit air thereto at all times when the engine is running, a valve controlling the admission of air to the secondary mixing chamber durin only a part of the engine operation, an means operated by the throttle for automatically and variably controlling the opening movement of one of said valves, during operation'of the engine under varying operating conditions. 7

4. A chargev forming device for internal combustion engines comprising a primary mixing chamber, means for supplying fuel and airwthereto, a secondary mixing chamber into which the primary mixing chamber delivers, spring held primary and secondary valves controlling the admission of air to said mixing chambers respectively, the spring of said primary valve being weaker than that of the secondary valve wherebya low suction is maintained in the primary mixing chamber under certain operating conditions, and means for automatically increasing the pressure of said spring under other operating conditions.

5. A charge forming device for internal combustion engines comprising a primary mixing chamber, means for supplying fuel and air thereto, a secondary mixing chamber into which the primary mixing chamber delivers, a primary throttle controlling the flow from said primary mixing chamber, a secondary throttle regulating the secondary mixing chamber, primary and secondary air valves controlling the admission of air to said mixing chambers, means for resisting the opening of said primary air valve, common operating mechanism for operating both said throttle valves and controlling the effectiveness of said resisting means.

6. Acharge forming device for internal combustion engines comprising a rimary mixing chamber, means for supplying fuel and air thereto, a secondary mixing chamber into which the primary mixing chamber delivers, a primary throttle controlling the flow from said primary mixing chamber, a secondary throttle regulating he secondary mixing chamber, means for opening the secondary throttle after the primary throttle be ins to open, primary and secondary air va ves controlling the admission of air to said mixing chambers and means connected to the secondary throttle for controlling the opening of the primary air valve during the opening of said secondary throttle.

7. A charge forming device for internal combustion engines comprising a primary mixing chamber means for su plying fuel and air thereto, a: second mixing chamber into whichthe primary m xing chamber dethrottle, 7

primary throttle with said arm, spring closedprimary and secondary air valves controlling livers, a primary throttle controlling the flow from said primary mixingchamber, a secondarythrottle regu valves controllin -the admission of air to 's'aidmixingch'am rs, means operable to resist the'opening of the primary air valve, and

means operable after a predetermined opening movement of the primary throttle to increase the resistance to opening movement of I said primary air valve.

- 8. A charge formingdevice for internal combustion engines comprising a primary the admission of air to said mixing chambers, an arm engaging the spring of said primary air valve to increase the pressure of said spring on the valve, and a link connecting said arm and the operating arm of the sec ondary throttle.

' 9. A charge forming devicefor multicylinder engines comprising a: plurality of sec ondary mixing chambers, a plurality of primary mixing, chambers associated t erewith and supplying rimary mixture thereto, means supplying uel to said primary mixing chambers,

controlling" the fiowfrom said primary and secondary throttles, a; sin le' primary air valve for admitting air to al? mixing chambers, a single secon valve foradmittingair to all of said sec-i th ondary air chambers and means operated by of said rimary the secondary throttle for controlling the operations of said primary air valve.

- flow from said primary mixing chamber, a: isecondary throttleregulating the secondary mixing chamber, primary and secondary air 10.- A charge forming device for internal combustion engines comprising a rimary mixing chamber, P

intc which the primary mixing chamber delivers, a primary throttle controlling the valves controllingthe admission of air to said the opening of the' primary air valve, and

I means operable by the secondary throttle after a predetermined movement thereof to increase the resistance of said resisting means.

11. A charge-forming device for internal combustion engines comprising a primary -m'ixing chamber, means forsupplying fuel lating the secondary mixing chamber, p'nmaryand secondar air air thereto, I chamber,a primary mixture conduit'adaptfrom the prithrottles con-.

primary and secondary throttles" ary air chamber, means for supplying fuel and air thereto,'a secondary mixing chamber" and air thereto, a secondary mlxmg' chamber into which the primary mixing chamber delivers, spring hel primary and secondary valves controlhng the admission of air to said mixing chambers, the. springof "said primary valve beingweaker than" that of the secondary valve whereby alow suction is under certain operating conditions, and

.means effective to increase the pressure of the spring. on the lprimary air valve on opening-0f the thrott e.

12. A charge forming device-for internal combustion engines comprising a" rimary mixing chamber, meanssupplying Kiel and a throttle, a secondary ed to convey primaryv mixture mary'chamber to said-secondary chamber, a spring held valve controlling air to the primary mixing chamber and adapted-to open under relatively low suction, a spring held valve controlling admission of air to the secondary-mixing chamber and openingonly under relatively high suction, and .means for automatically varying the spring pressure on the'primary air valve. 13. A charge forming device for internal combustionenginescomprisingaprimarymixing chamber, means supplying fuel and air thereto, a throttle, a secondary mixing chamber, a primary mixture conduit adapted to convey primary mixture fromthe primary chamber to said secondary'chamber, a spring held valve'controlling admission of air to theprimary mixing chamber and adapted to open under relatively low" suction, a spring held valve controlling admission the secondary mixing chamber and opening only under relatively high suction, and means operable throttle for var'yingthe spring pressure on e'primary air valve. 14. A charge forming device for internal combustion engines comprising a primary mixing chamber, means supplying fuel and air thereto, a throttle, a secondary mixing a primary mixture conduit adapted to convey primary mixture from the primary chamber to said secondary chamber, a spring held valve controlling admission of air to the primary mixing chamber and adaptedto openunder'relative'ly low suction, a spring held valve controlling admission of air to the secondarymixing chamber and opening only under relatively high suction, m xing chambers, means operable to resist combustion engines comprising a primary;

mixing chamber, means for supplying fuel and air thereto, a throttle controlling the flow therefrom,a secondary mixing chamber towhich the primary mixing chamber supadmission of of air toduring opening movements of the maintained in the primary mixing chamber 7 plies a primary mixture of fuel and air, a primary air valve admittlng air to the primary mixing chamber at all times when the engine is running, a secondary air valve admitting air to the secondary mixing chamber during only a part of the engine operation, and means operated by the throttle for variably controlling the opening movement of the primary air valve during all opening movement of the secondary air valve.

16. A charge forming device for internal combustion engines comprising a primary mixing chamber, means for supplying fuel and air thereto, a throttle controlling the flow therefrom, a secondary mixing chamber to which the primary mixing chamber supplies a primary mixture of fuel and air, a

primary air valve admitting air to the primary mixing chamber at all times when the engine is running, a secondary air valve admitting air to the secondary mixing chamber during only a part of the engine operation, means operated by the throttle for operating the secondary air valve, and means connected to the secondary aircvalve for variably controlling the opening movement of the primary air valve after the secondary air valve begins to open.

17. A charge forming device for internal combustion engines comprising a primary mixing chamber, means for supplying fuel and air thereto, a throttle controlling the flow therefrom, a secondary mixing chamber to which the primary mixing chamber supplies a primary mixture of fuel and air, a spring closed suction operated primary air valve, a suction operated air valve admitting air to the secondary mixing chamber; and means operated by the throttle for increasing the spring pressure on the primary air valve as the throttle is opened.

18. A charge forming device for internal combustion engines comprising a primary mixing chamber, means for supplying fuel and air thereto, a throttle controlling the flow therefrom, a secondary mixingchamber to which the primary mixing chamber "supplies a primary mixture of fuel and air, a spring closed suction operated rimary air valve, a secondary air valve admitting air to the secondary mixing chamber only, and

J means operated by the throttle for increasing the spring pressure on the primary air va ve only during the opening movement of the secondary air valve. 1

In testimony whereof I hereto aflix my signature.

JEROME I. ANSON.

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