US1839129A - Charge forming device - Google Patents

Description

Dec. 29, 1931. w. H. TE ETER CHARGE" FORMING DEVICFE Filed Oct. 2, 1929 2 Sheets-Sheet ,1 i. a a

w. H. TEET ER CHARGE FORMING DEVICE Filed 001:. 2, .1929

Dec. 29, 1931.

2 Sheets-Sheet 2 Patented Dec. 29, 1931 UNITED STATES WILFORD H.

TEETER, OF DAYTON, OHIO, ASSIGNOR TO DELCO PRODUCTS CORPORATION,

OF DAYTON, OHIO, A CORPORATION OF DELAWARE CHARGE FORMING DEVICE Application filed October 2, 1929. Serial No. 396,702.

This invention relates to charge forming devices for internal combustion engines, and more particularlyto devices of this (name. ter which comprise a plurality of primary carburetors which deliver a primary mixture of fuel and air to a plurality of secondary mixing chambers located adjacent the engine intake ports, and in which the primary mixture is mixed with additional air under certain operating conditions.

Devices of this character are disclosed in the copending applications of Fred E. Aseltine, Wilford H. Teeter, and Carl H. Kindl, Serial No. 288,683, filed June 10, 1928, and Carl H. Kindl and Frederick D., Funston, Serial No. 396,709, filed October 2, 1929,'the present invention being in the nature of an improvement on the device disclosed in the later of these applications.

It is the object of the present invention to provide means for enriching the mixture during the acceleration period, which is effective to enrich said mixture substantially simultaneously with the opening of the throttle and to vary the degree of enrichment of the mixture during the throttle movement. More particularly, it is the object of this invention to provide means which is effective to enrich the mixture to a relatively great extent during the first part of the acceleration period and to a lesser degree during the remainder of said accelerating period.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawingswherein a preferred embodiment of one form of the present.

' invention is clearly shown.

device constructed in In the drawings: Fig. 1 is a plan view of a charge forming ccordance with the present invention.

Fig. 2 is a vertical, longitudinal section through'the carburetor unit forming part of the charge forming device and one outlet branch of the manifold associated therewith, on line 2-2 of Fig. 1.

Fig. 3 is a side elevation of the carburetor unit being partly broken away to show certain parts in section.

Fig. 4 is a section on theline 44 of Fig. 2.

'Fig. 5 is a detail view of the means for operating the fuel valve.

The device disclosed comprises a main air manifold 10 having three outlet branches 12, 14 andl6, each of which is provided with a flange 18 for securing the manifold to the en gine block in the usual manner. The manifold is also provided with a flange 19, to

. which the carburetor unit hereinafter described is-secured. 7

I 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 upper 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 the nozzles are formed, is secured by screws to the lower wall of housing 20, and a sheet metal fuel bowl 32 is held tight against an annular shoulder 34 on the housing 20 by any suitable means, such as a machine screw 35 passing through the fuel bowl and screwed into the bottom wall of the main housing. 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, operating 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 whichis 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 the vertical fuel passage 42 communicating at its upper end with thehorizontal fuel canal 44, which connects with each of the nozzles 38. 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 5O controlled by a valve 52, operated in the 38 to the prlmary mixing chambers by the suction therein and the flow is regulated by' a two stage metering valve 53 received in chamber 54 and having a passage 55 therethrough to regulate the flow when the valve is seated, but which is adapted to be unseated as the suction increases to permit a flow of fuel around the valve also. Moreover, on any reduction in mixing chamber suction which might permit the fuel column to drop sufficiently to cause a temporary fuel starving of the engineJthe said valve partially checks the return flow of fuel to largely prevent such an action as such valve immediately seats and the return flow will be limited by the small orifice in the valve.-

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 chamher. At relatively high speeds, the mixing chamber suction is sufiicient 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 flowing 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 anterior ends of the primary mixture passages 64, which are parallel to each other and close together, as indicated in Fig. 2. When the carburetor is attached to the manifold, these passages register with conduits which convey the pri-' mary mixture to the secondary mixing chambers. These conduits comprise angular passages 66 indicated in dotted lines in Fig. 1, which communicate with pipes 68 leading to elbows 70, secured to the manifold and communicating in turn with tubes 72, located in the outlet branches 12 and 16 of said manifold. The middle passage 64 communicates directly with a tube 74 similar to the tube 7 2 and fully illustrated in Fig. 2. Restrictions 76 separate the primary mixing chambers from the remainder of the mixture passages so as to reduce the velocity of flow past the fuel nozzles for a purpose fully set forth in the above mentioned copending applications.

A single throttle valve 78, which extends across all of the primary mixture passages,

controls the flow therethrough and is proper hour on the level.

92, fixed in the main housing20, and serving also as a guide for the vertically reciprocatmg stem 94, to which the air valve is secured in any desirable manner. When it is desirable to choke the carburetor to facilitate "starting of the engine, the flange 88 is adapted to be lifted by means not shown herein but fully illustrated and described in the above applications, until the'upper end of the sleeve 90 flows to the primary mixture passages through an opening 100 in the bottom wall of the air chamber and to the secondary mixing chambers through a passage 102, which connects with the inlet of the manifold 10. The flow of air through this passage. is controlled by a manually operable throttle 104,

secured to a shaft 106, rotatably mounted I in the main housing and adapted to be operated by the primary throttle, as hereinafter described.

The operating mechanism for the two throttle valves comprises an arm 108, secured to a spindle 109, projecting from one end of the primary throttle outside the main housing and provided with an orifice 110, for

connection with some suitable operating con- I nection extending to a point convenient to the operator of the vehicle. The arm 108 is provided with an extension 112 having a projectingpin 114 supporting a roller 116, which is received within a cam slot 118, formed in an arm 120, secured to the end of the shaft 106 by a split clamp 122, or in any other desirable manner. As the arm 108 is rocked to open the primary throttle, the roller 116 engaging in the cam slot is operative to rock the shaft 106 to open the valve 104. The slot 118 may be of any desired contour to give the desired amount of movement to the valve 104 and is generally so designed that a part of such slot is concentric with the spindle 109, so that a portion of the-movement of the arm 112 is ineffective to move the valve 104. This concentric part of the slot 118 may be of any desired length but is usually so formed that the valve 104.- begins to open when the primary throttle has reached a position corresponding to a vehicular speed of approximately=20 miles After the valve 104 egins to open, such valve moves simultaneously with the primary throttle until both are fully open. While the operating' mechanism disclosed herein is specifically.

different from that disclosed in the earlier above copending application, the function of such Inechanismis substantially the same as that. described therein and the valves are operated in substantially the same manner to produce the same result. a On opening of one or both throttle valves, the suction in the air chamber 98 is increased and the air valve is opened to admit additional air and increase the quantity of mixture supplied to the engine. The opening of the air valve is retarded to prevent fluttering thereof and to restrict the admission of air to prevent leaning of the mixture whenever the valve is opened. For this purpose a dashpot is provided comprising a cylinder 130 formed in 'the'casting 30 and receiving fuel from the reservoir 32. Cooperating with this cylinder is a piston 132, secured to the lower end of the valve stem by a nut 134, as indicated in Fig. 2. The specific construction of this dashpot is immaterial so far as the present invention is concerned and may be of any conventional design which will properly retard the opening of the air valve.

In order to provide a mixture of the proper proportions to most properly operate the engine during the acceleration period, a pump is also provided to supply additional fuel whenever the primary throttle is opened. This pump comprises a cylinder 136 formed in the casting 30 and a piston 138 cooperating therewith, which is normally held in its uppermost position by a spring 140, received between the piston and-the bottom of the cylinder, as. indicated in Fig. 3. The pump piston is operated by the primary throttle through a resilient operating connection comprising an arm 142', secured -to spindle 109, and is pivotally connected at its free 'end to a piston rod 144, which is adapted to operate the pump piston. The lower end of this rod projects into a tube 146, which is closed at the bottom, as indicated in Fig. 3, and has a flange 148 projecting therefrom which fits slidably in a small cylinder 150, formed within'the pump piston and closed at the bottom by a cap 152, a spring 154 being provided between the bottom of the tube 146 and thecap 152. On opening movement of the throttle, the rod 144 is depressed and the spring 154 is compressed until the force of such spring is suflicient to overcome the resistance of the-spring 140, which normally holds the pump piston in its upper position, after which the pump piston is moved downwardly with the rod 144, forcing fuel from the cylinder 136 into afuel delivery conduit which includes a chamber 156, which connects with said cylinder 136 by a passage 157 at the bottom of the cylinder.

Screwed into the chamber 156 is a sleeve 158, which is closed at its lower end except for a restricted passage 160, normally closed by a check valve 162, slidable within the sleeve and adapted to be lifted on downward movement of the pump piston to permit the passage of fuel from the chamber 156 into a vertical passage 164, bored in the casting 30 and connecting at its upper end with a horizontal passage 166, bored in the main housing, which, when the device is assembled, communicates with an angular passage 168, formed in the wall of the manifold. The passage 168 is adapted to connect with a vertical passage 170, bored in a block 172, which is secured to the lower side of the manifold by screws, as indicated in Fig. 1, or in any other desirable manner. A passage 174, transverse with respect to the cylinder block, is bored in block 172 and communicates with another horizontal passage 176, which supplies fuel to three short vertical passages 178, each of which leads to an enlarged chamber 180, formed in the block 172, and each of which receives a check valve 181, functioning in a manner hereinafter described.

Nipples 182 of identical construction communicate with the chambers 180 and are connected by coupling members 184 of identical form with tubes 186, 188 and 190, which are designed to supply fuel to auxiliary reservoirs 192, 194 and 196, formed in the manifold casting on top of the outlet branches 12, 14

and 16 of the manifold respectively. The

above mentioned tubes are connected to the reservoirs by any suitable form of pipe coupling, for example, by nipples 198 and coupling members 200, which are identical in construction for all of said reservoirs.

As shown in Fig. 2, these reservoirs are closed at the top by removable cover plates" 202, secured" in position by screws 204. An orifice 206 is provided in the center of each cover plate to admit air for the purpose of maintaining substantially atmospheric pressure therein. Associated with each auxiliary reservoir is a fubl delivery tube 208, adapted to convey fuel therefrom to the primary mixture tubes 72 and 74, which extend through the outlet branches of the manifold. These fuel delivery tubes are identical in form and one of such tubes is disclosed in detail in Fig.

2. Each tube is screwed into the wall of the manifold and at its upper end projects into i the auxiliary fuel reservoir with which it is associated to a point relatively near to the top thereof. Each tube is provided with an unrestricted passage 210 therethrough which is open at the top, as indicated in- Fig. 2,

and also communicates with the associated fuel reservoir by means of a short passage or orifice 212 of considerably smaller size than the passage 210. Each fuel delivery mechanism will now be briefly described. r

On any opening movement of the throttle, the fuel pump is effective to force fuel into all of the auxiliary fuel reservoirs simultaneously. This fuel is delivered through the fuel delivery tubes 208 into the primary mixture tubes 72 and 74 and as long as the level of fuel within the auxiliary fuel chambers is above the upper end of theifi'ieldelivery tubes 208, the flow of fuel from the: reservoirs Will be relatively rapid and will be limited only by the size of the passage 210. As soon, however, as the level of fuel within the chambers falls below the upper end of the tubes 208, fuel flows from the chambers only through the restricted passages 212, which are of much smaller size than the passages 210. This will, therefore, bring about a reduced rate of flow from said auxiliary fuel chambers and will prolong the time during which the additional fuel is supplied to the primary mixture. Since it has'been found that a relatively rich mixture is needed at the beginning of the acceleration period and a less rich mixture during the remainder of such period, and, also that it is desirable to provide the latter over an appreciable period of time, this device has been found to produce very desirable results.

In Fig. 5 there is disclosed the means for operating the fuel valve 52 hereinbefore referred to. Secured to theleft end of the primary throttle,'as seen in Fig. 1, is a cam 220, which is adapted to engage an operating arm 222, pivoted at 224 on the main housing and connected at the opposite end to the upper end of the valve 52. After a predetermined opening movement of the .primary throttle, the cam depresses the arm 222 and moves the fuel valve downwardly to permit a flow of fuel through the inlet 50.

- 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 mixture passage adapted to communicate with the intake ports of the engine, a main .fuel reservoir, means for supplying'fuel and air to said mixture passage, a throttle, and means operative on any opening movement of the throttle for supplying additional fuel to said mixture passage durlng the acceleration period, said means being constructed to supply a relatively -lar e amount of fuel when first effective and susequently a lesser amount of fuel. i i i 2. A charge forming device for internal combustion engines comprising, a mixture passage adapted to communicate with the intakeports of the engine, a main fuel reservoir, means for supplying fuel and air to said mixture passage, a throttle, and means for supplying additional fuel adjacent the ofit let end of said mixture passage on any opening movement of the throttle, said means being constructed to supply a relatively large amount of fuel when first efiective, and subsequently a lesser amount of fuel.

3. A charge forming device for internal combustion engines comprising, a mixture passage adapted to communicate with the intake ports of the engine, a main fuel reser voir, means for supplying fuel and air to said mixture passage, a throttle, and means operative on any opening movement of the throttle for supplying additional fuel to said mixture passage during the acceleration period, said means comprising an auxiliary fuel reservoir having a plurality of outlets of different size, Which are adapted to be rendered ineffective successively.

4. A charge forming device for internal combustion engines comprising, a mixture passage. adapted to communicate with the intake ports of the engine, a main fuel reser voir, means for supplying fuel and air to said mixture passage, a throttle, and means operative on any opening movement of the throttle for supplying additional fuel to said mixture passage during the acceleration period,

,said means comprlsmg an auxiliary fuel resture passage during the acceleration period,

said means comprislng an auxiliary fuel reservoir, a fuel delivery passage, and orifices of different size connecting the fuel delivery passage with the reservoir, said orifices being so arranged that the larger orifice is rendered ineffective while fuel continues to flow into said delivery passage through the smaller orifice. p

6. A charge forming device for internal combustion engines comprising a mixture passage adapted to communicate with the intake ports of the engine, a main fuel reseIfvoir, means for supplying fuel and air to said mixture passage, a throttle, and means operative on any opening movement of the throttle for supplying additional fuel to said mixture passage during the acceleration period, said means comprising an auxiliary fuel reservoir, a fuel delivery tube projecting upwardly into the reservoir and open at the top to communicate'directly with the reservoir, and another orifice connecting the fuel delivery tube with the reservoir near the bot- Y said mixture passage, a throttle, and means operative on any opening movement of the throttle for supplying additional fuel to said mixture passage during the acceleration period, said means comprising an auxiliary fuel reservoir, a fuel delivery tube projecting up wardly into the reservoir and having an unrestricted opening at the top communicating with the reservoir, and another smaller orifice connecting the fuel delivery tube with the reservoir near the bottom, whereby the rate of flow from the reservoir is less after the fuel therein falls to apredetermined level.

8. A charge forming device for internal combustion engines comprising, a mixture passage adapted to communicate with the intake ports of the engine, a main fuel reservoir, means for supplying fuel and air to said mixture passage, a throttle, an auxiliary fuel reservoir for supplying additional fuel to the mixture passage during the acceleration period following opening of the throttle, a fuel delivery passage and orifices of different size connecting the fuel delivery passage with the reservoir, said orifices being so arranged that they are rendered ineffective successively as the level of fuel within the reservoir falls, and means operated by the throttle on its opening movement for supplying fuel to the reservoir.

9. A charge forming device for internal combustion engines comprising a primary mixture passage, means for supplying fuel and air thereto, a secondarymixing chamber into which said primary mixture passage delivers, a throttle, a mainfuelreservolr, an auxiliary fuel reservoir .on the secondary mixing chamber adapted to supply additional I fuel to the primary mixture passage during the acceleration period, and a delivery conduit extending from said reservoir to the primary mixture passagev adjacent its delivery end, said conduit being-constructed so as to supply a relatively large quantity of fuel during the first part-of the acceleration period, and subsequently a lesser amount of fuel.

10. A charge forming device for internal combustion engines comprising a primary mixture passage, means for supplying fuel and air thereto, a secondary mixing chamber into which said primary mixture passage delivers, a throttle, a main fuel reservoir, an auxiliary fuel reservoir formed in the wall of the secondary mixing chamber and adapted to. supply additional fuel to the primary mixture passageanda fuel delivery tube for delivering fuel from said reservoir to the priber, communicating with the primary mixture passage and projecting into the auxiliary fuel reservoir so as to communicate with said reservoir near the top, and an orifice in said tube communicating with said reservoir near the bottom.

12. A charge forming device for internal combustion engines comprising a plurality of primary mixture passages, means for supplying fuel and air thereto, a plurality of secondary mixing chambers into which said passages deliver, a main fuel reservoir, a

throttle, an intake manifold having outlet branches communicating with the engine intake ports and in which said secondary mixing chambers are located and through which the primary mixture passages extend, a plurality of auxiliary fuel reservoirs formed in the walls of the outlet branches of said manifold, and deliverv conduits adapted to con- 'vey fuel from said reservoirs to the primary mixture passages within said outlet branches on any opening movement of the throttle.

13. A charge forming device for internal combustion engines comprising a plurality of primary mixture passages, means for supplying fuel and air thereto, a plurality of secondary mixing chambers into which said passages deliver, a main fuelreservoir, a

throttle, an intake manifold having outlet branches communicating .with the engine intake ports and in which said secondary mixing chambers are located and through which the-primary mixture passages extend, a plurality of auxiliary fuel reservoirs formed in the walls of the outlet branches of said manifold, delivery conduits adapted to convey fuel from said reservoirs to the primary mixture passages within said outlet branches,

and meansoperated by the throttle on any opening movement thereof for supplying fuel to all of said auxiliary reservoirs simultaneously.

14. A charge forming device for internal combustion engines comprising a mixture passage adapted to communicate with the intake ports of the engine, a main fuel reservoir, means for supplying fuel and air to said mixture passage at a point relatively remote fromthe engine intake ports, a throttle, and means for supplying additionalfuel adjacent the outlet end of the mixture passage during the acceleration period, said Vmeans being constructed to supply varying amounts of fuel per unit oftime during said acceleration period.

1 5. A charge forming device for internal combustion engines comprising a mixture passage adapted to communicate with the intake ports of the engine, a main fuel reservoir, means for supplying fuel and air to said mixture passage at a point relatively remote from the engine intake ports, a throttle, and means operated by the throttle for supplying additional fuel adjacent the outlet end of said mixture passage on any opening m'ovement of said throttle, said means being constructed to supply varying amounts of fuel per unit of time throughout the opening movement of said throttle.

16. A charge forming device for internal combustion engines comprising a mixture passage adapted to communicate with the mtake ports of the engine, a main fuel reservoir, means for supplying fuel and air to said mixture passage at a point relatively remote from the engine intake ports, a throttle, and means operated by the throttle for supplying additional fuel adjacent the outlet end of said mixture passage on any opening movement of said throttle, said means being so constructed that the rate of fuel flow becomes progressively less as said additional fuel is supplied to the mixture passage.

In testimony whereof I hereto afl'ix my signature.

WILFORD H. TEETER.

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