US1931599A - Charge forming device - Google Patents

Description

Oct. 24, 1933; F. E. ASELTINE CHARGE FORMING DEVICE Filed May 23, 1930 3 Sheets-Sheet l Oct. 24, 1933. F. E. ASELTINE 1,931,599

CHARGE FORMING DEVICE Filed May 25', 1950 3 Sheets-Sheet 2 Oct. 24, 1933.

F. E. ASELTINE CHARGE FORMING DEVIC E Filed May 23, 1930 3 Sheets-Sheet 5 p. Mn W WE 2/2 /76 x72 /90 2/! J INVENTOR BY 5 M WM) ATTORNEYS Patented Oct. 24, 1933 UNITED STATES 1 1,931,599 cannon roams nnvrcn Fred E. Aseltine, Dayton, Ohio, assignor to Delco 7 Products Corporation, Dayton, 0hio,'a corporation of Delaware Application May 23, 1930. Serial No. 454,914 12 Claims. (01. 261-47) This invention relates to charge forming devices for internal combustion engines and more particularly to devices of this character which comprise a plurality of primary carburetors, each of which delivers a. primary mixture of fuel and air to one of a plurality'of secondary mixing chambers located adjacent to the engine intake ports and in which the primary mixture is mixed with additional air under certain operating conditions. Devices of this character are shown in the copending application of Fred E. Aseltine et a1, Serial Nos. 360,404 and 370,179, filed May 4, 1929 and June 12, 1929 respectively. This invention is shown herein as embodied in both of these devices, since its action-is somewhat different in the different constructions.

It is the general object of the present invention to provide means for controlling thev admission of secondary air so as to restrict the amount of air supplied through the secondary air passage under all operating conditions inaccordance with the engine suction.

More specifically it is an object of the invention to provide devices for controlling the movement of the secondary air valve which are effective to permit the movement of the valve toward open position by suction of the engine, are effective under certain operating conditions to move the valve toward closed position to a degree determined by the suction of the engine and under other operating conditions are effective to close the valve as the throt-le is closed.

These objects are accomplished accordingto the present invention by the provision of means operated by the throttle for closing the valve mechanically as the throttle is closed, the provision of a valve which isoperable entirely by engine suction on its openingmovements and the provision of a weight for moving the valve toward closedposition on reduction of enginesuction, while the throttle remains inflxed position, to a position where the .engine suction balances the effect of the weight.

Further objects and advantages of the present invention will be apparent from the following description, reference being hadto the accompanying drawings wherein a preferred embodiment of oneform of the present invention is clearly shown.

In the drawings:

Fig. 1 is a vertical section through the carburetor unit and one outlet branch of the manifold.

Fig. 2 is a left side elevation of the carburetor as shown in Fig. 1.

of the housing by any suitable means'and my unit partly broken away to show certain parts in section.

Fig. 3 is a fragmentary elevation of the carburetor unit viewedfromthe left in Fig. 2.

Figs. 4, 5 and 6 are views similar to Figs. 1, 2 and 3 respectively showing the invention embodied in a modified form of carburetor.

Fig. 7 is a detail view of a valve operating connection embodied in the form of device shown in Fi s. 1 to 3.

Fig. 8 is a detail view of partof the device shown in Figs. 4 to 6.

Fig. ,9 is a diagrammatic view of the device shown in Figs. 4 to 8 inclusive. v

The device disclosed in Figs. 1 to 3 and 7 comprises a main air manifold 10,'havin'g threeoutlet branches, the middle branch 12, being shown herein, each of these branches communicates .with one of the intake ports of a multi-cylinder engine and-each is provided with an attaching l6 flange 16 for securing the manifold to the engine block in the usual way,- while adjacent its inlet v the manifold is provided with a flange .18 to which the main carburetor unit is' adapted tube secured The carburetor unit comprises a main housing 20, having a flange '22, adapted to be' 'secured to the flange 18 by screws 24. An air inlet coupling 28 is securedin an openin in the top be connected to an air cleaner if desired.- A casting 28, in which the passages supplying fuel to the nozzles are formed, issecured inany dcsirable manner to thebottom of the main housing and a fuel bowl 30 is'held tight against the bottom of'said housing by any suitable means. Fuel is supplied to the bowl by means not shown, and a float '32 maintains a substantially constant level of fuel therein in the usual way,

Twofuel nozzles 34 and 36 are provided in each primary mixing chamber 38, the structure of which is more fully described later. The nozzle 34 supplies all of the fuel at idling andrelatively lowspeed operation, and a part of the fuel at all other times while the'nozzle 36 is ineffective until the throttle has been opened a-considerable-distance and the engine is running at relatively high speed;- The nozzles are. supplied with fuel through separate fuel passages; that supplying the nozzles 36 being closed at relative 106 low speed operation. The fuel nozzles, the passages supplying fuel thereto'and means for controlling'the flow therefrom are fully shown and described in the earlier of the above applications, such structure forming no part of this invention. no

Both nozzles 34 and 36 are provided with restrictions 40 to regulate the flow therethrough.

Each low speed fuel nozzle isprovided with a main fuel outlet 42 in the top 01. the nozzle and a secondary fuel outlet comprising two orifices I 44 and 46 in the wall of the nozzle near the bottom of the mixing chamber, said nozzles functioning in the manner set forth in application 360,404.

The primary mixing chambers form the enlarged inlet ends of primary mixture passages 48 which are parallel and close together. When the carburetor is secured to the manifold these passages register with primary mixture conduits which convey the primary mixture to the second-,- ary mixing chambers. Restrictions 50 separate the mixing chambers from the remainder of the primary mixture passages, and passages 52 admit air immediately posterior to the .restrictions to reduce the velocity of flow past the nozzles, all of this structure being fully described in application 360,404.

A single primary throttle valve 54 operated in a manner briefiy describedhereinaiter extends top of the air valve.

across all of the primary mixture passages to control the flow therethrough, and is provided with grooves 56 which register with such passages.

Air entering the carburetor is supplied through the coupling 26 and is controlled by a main air valve 58 normally held against a seat 60, by a spring 62 received between the valve and a flange 64 projecting from a sleeve 66, slidably mounted on a stationary sleeve 68, fixed in the main housing and guiding the air valve stem 70. In order to choke the carburetor to facilitate starting, the valve may be lifted by means, (not shown) until the sleeve 66 engages the air valve to hold it closed. Air to carry the starting fuel to the intake ports is admitted through slots 72 in the The valve 58 admits air to an air chamber 74 from which it flows to the primary mixing chambers through an opening '76 in the bottom of the inlet, and controlled by manually operated valves and 82, secured to shafts 84 and 86 respectively mounted in the main housing, the valve 80 being hereinafter termed a. secondary throttle", for convenience.

'[ The operating means for the primary and secondary throttles forms no part of this invention and is not illustrated herein, but the mode of operation of the throttles will now be briefly set forth in order to enable a better understanding of the operation of the whole device. The secondary throttle is operated by the primary throttle through the medium of operating mechanism which permits certain independent movement of the'primary throttle and is generally designed to permit the primary throttle to move independently of the secondary until it reaches a position corresponding to a vehicular speed of approximately 15-20 miles per hour on a level.

cylinder. The cylinder is filled with fuel by leakage around the piston and the resistance of the dash pot is controlled by an auxiliary piston 92 in the manner fully described in application 360,404. However, the structural details of the dash pot are not material to the present invention and any conventional dash pot may be employed.

As previously stated the primary mixture passages communicate, when the device is assembled, with conduits fcrmed in the manifold. The middle one of these conduits is shown herein and comprises a straight passage 94 in the manifold casting in which is received a tube 96 which extends through the branch 12 of the manifold. The conduits supplying primary mixture to the two end branches of the manifold are of the form shown in the earlier application.

The valve 82 is opened, on opening of the valve 80, as in the earlier application, entirely by engine suction and the opening movement of the valve is temporarily retarded for the same purpose, this being to retard the flow of pure air through the secondary air passage while increasing the velocity of flow through the primary mixture passages in order to facilitate enrichment of the mixture during the-acceleration.

erally from a bell crank lever' 102, rotatably' mounted on a boss 104 projecting from the main housing and in which'the shaft 86 is journalled. The bell crank lever has an arm 106 which is pivotally connected to a short link 108 pivotally connected to a lever 110 pivoted on a pin 112 screwed intothe main housing and connected at-its opposite "end to a rod 114. This rod extends to a piston (not shown) which is slidable in a dash pot cylinder'116, the top of which is shown in Fig. 2. The dash pot is of exactly the same construction as that of the application 360,404, and in order to simplify this disclosure as much as possible has not' been shown herein.

Normally, when the valve 80 is closed the valve 82 is held closed by a spring 117, connected" at one end to an arm 119, secured to the opposite end of shaft 84 and at its other end to a link 121 having slots 123 and 125 therein through which project pins'127 and 129, extending from'the arm 119 and an arm 131 secured to the end of shaft 86, respectively. This construction is shown in Fig. 7 and the parts are held in the position shown therein, when the throttle is closed. In this position the spring 117 is tensioned and through the medium of the link 121, pulls the arm 131 to the left to move the valve 82 in a clockwise direction to closed position. On opening movement of the throttle the arm 119 is moved counter-clockwise relieving the tension of spring 117 and permitting the valve 82to open under influence of engine-suction, while on closing movement of the throttle, the clockwise movement of arm 119 again tensions the spring to efiect closing of the'valve 82, all

nections extending to the dash pot piston, the latter is lifted until thevalve assumes the position determined by the' suction. If the throttle be opened wide; and theengine be operating at high speed, the valve 82 will occupy a sub-- stantially horizontal position. If, however. the

load is increased, as'when'the vehicle on which the device is employed ascends a hill,'the engine speed is decreased with a corresponding decrease in suction. Under such conditions the auxiliary air valve 82 willtend to move toward closed position. In the device disclosed in ap-- plication 360,404, when the valve 82 is positively connected to the dash pot piston-there is nothing position.

According tothis invention the valve is not directly connected to the dash pot piston so its closing movement on decrease ofsuction, is not affected by the piston, and means are provided to move the valve relatively rapidly to the position determined by the engine suction. *This means comprises a weight 120 which. is secured "to the shaft 86 and extends substantially horizontally therefrom, when the valve is in closed position, as in Fig. 2, so that the greatest effect of the weight is had when the valve nears its closed position and the suction eifective on the valve is relatively low. This weight causes the valve to float in the air stream and when the throttle is in fixed position, causes the valve totake different positions in accordance with thesuction effective on the valve, and to move to such positionsrelatively rapidly as the suction changes. On suchmovements of the valve 82, the dash pot piston and connected parts move slowly until the arm 98 engages this arm 100. On closing movements of the throttle 80, the valve is closed by the closing spring as in the earlier device, while the dash pot piston and associated parts are moved to normal position as previously described.

It was found that in the device shown inapplication 360,404, insufficient restriction to the admission of secondary air might occur temporarily. on operation at heavy load with widev I the medium of the arm 1 54 and pin 156. If, how- 125 ever, the throttle and the valve,are wide open and an increase of load occurs, a decrease in sucopen throttle, resulting at times in too low suction at the fuel jets in the primary'mixture passages. and a. temporarily insuiiicient supply of fuel. This invention is effective to produce at all times the proper degree of restriction on the flow of secondary air, to form a mixture of correct proportions under all operating conditions.

The construction of the secondary mixing chambers and other elements'of this device, which have not been shown and described herein are substantially the-same as in the earlier'application and no further illustration is thought necessary.

In the deviceshown in the later application 370,179, the piston of the dash pot which controls motion of the auxiliary air valve is'moved downwardly when the valve is opened. Consequently, on decrease of suction in the secondary air passage under such operating conditions as previously referred to, the auxiliary air valve will not close at all being held open by the weight of the dash pot piston and connected parts. The above described weight for closing the auxiliary valve is therefore even more useful in the later form of charge forming device than the earlier: and its application thereto is shown in Figs. 4, 5, 6 and 8.

'present invention."

and138 respectively jou'rnalled in the main hous- The opening movement-df -the-valve 134 is retarded by a dash pot comprising a' cylinder 140 and a piston 142 slidable therein, a check :valve '--144 operating to prev'ente'scape of fuel from the cylinder on opening of the valve but permitting a For the purpose of simplifying the disclosure as much as possible} the specific construction'of this later device will not be incorporated herein except those parts immediately'associated with the In the device shown in Figsg' 4, 5, 6 and 8 the secondary air passage isindicated at 130 and is controlled by a secondary-throttle1-32 and "a suction operated valve 134 secured to shafts 136 free return movement ofthe dashpot piston. The piston 142 is pivotally connected to a'link 146 which at its upper end is pivotally connected to an arm 148,-which, in the device shown in application 370,179 was secured to the shaft 138 on which the auxiliary valve is mounted. Ac-" cording to this invention the arm 148 is pivotally mounted on the shaft 138 and isadapted to be engaged by a toe 150 projecting laterally from an arm 152 secured to the shaft 138 adjacentthe arm 148. On opening movements of the auxiliary valve the toe 150 'engages the arm 148 to move the dash pot piston downwardly, the opening of the valve thus being retarded by the 'dash shown in FigI-S, when'thethrottle'is closed. In

this position a pivoted arm-154 is' 'hel'd in en: gagement vn'th' a pin 156 projecting-fromthe link 146 by'a spring '158, -'one end of which is connected to-anear 160- projecting from the arm 154 andthe other't'o a' pin 162 projecting from the main housing. On opening of the throttle a pin 164 is moved into engagement withthe arm 154' and then moves said arm out of en-. gagement with the pin 156 to permit the valve 134 to be opened by engine suction inthemanner fully described in application 370,179. On-clos- 1 ing movement of the throttle thepin 1641s restored to normal'position' and'the spring1-58 operates to close the auxiliary air valve through tion is produced and the auxiliary air valve should close'to an extent-determined by the reduction in suction. -With the structure disclosed inap- 13 plication 370,179 this was impossible because nothing was'provided to close the'valve and the weight of the dash pot piston and connected. parts would operate to hold the valve wide open, resulting in unsatisfactoryengine operation under such circumstances. According to this invention a weight 166 is provided-to close the valve 134 to a position where the weight is balmoved. The auxiliary'air valve is thus moved to a position under all operating conditions which is dependentupon the engine and at all times termined by that suction.

Fig.9 is a diagrammatic viewof the device shown in Figs. 4to Sinclusive, and is provided primarily to show the arrangement of the fuel passages which supply fuel to the mixing chambers, for normal operation and during acceleration, the throttle, air valves and the operating 7 connections therefor andthe dash pots which J control such air valves. The structure disclosed is verybriefly described hereinafter, merely to facilitate an understandingof the general construction and operation of :the device.

A plurality of fuel inlets 160 and 162 are provided and supplyfuel to each one of three air is formed, the emulsion passing through orifices 166 into angular primary mixture passages 168, there being three of these passages as shown in Fig. 6 and all of such passages are controlled by a primary throttle 170. A fuel passage 172 having a constantly open low speed fuel inlet 174 and two-high speed fuel inlets 1'16 and 1'78,

the effectiveness of which is controlled by valves 180 and 182 respectively, the valve 180 being manually operated and the valve 182 being operated by an arm 184 projecting from a rod 186 connected to the primary throttle for operation therewith and adapted to operate a pump piston 188 for supplying fuel during the acceleration period and more fully, described hereinafter.

- The pump piston 188 as it moves downwardly expels fuel from a cylinder 190 in which the piston slides through a passage 192 connecting with a vertical passage 194 controlled by a check valve 196 and delivering fuel to an auxiliary fuel reservoir 198, open to the air in the space above the fuel in the float chamber 201. Fuel is supplied from'this auxiliary reservoir to the primary mixture passages through orifices 200 in the vfloor of such passages, one of such outlets being shown in Fig. 9. Fuel is supplied-to the float chamber byya conduit 202 and its flow is controlled by a float 204 in the usual way.

An air valve 206 corresponding to the valve 58 of Fig. 1' has a dash ,pot piston 207 secured to the lower end of the stem on which the valve is mounted, such piston sliding in a cylinder 208 to which fuel is admitted through orifice 210. Opening of the secondary or auxiliary air valve 134 causes downward movement of the piston 142, as previously described. Movement of this piston is resisted by the piston 212 slidable in the cylinder 214 and normally retained in the bottom of such cylinder by the spring 216, an orifice 218 permitting a fiow of fuel from the cylinder 140 into the cylinder 214. After movement of the piston 142 ceases, the piston 212' is moved by thespring 216 to the position shown in the drawings so that any subsequent opening of the valve 134 is resisted-inthe same mannerand to the same degree.

While the form of embodiment of the present invention as herein disclosed, constitutes a preengines, comprising a mixture passage, means for supplying fuel and air thereto, a throttle, an auxiliary air valve for controlling admission of air to said mixture passage, said valve being operated by engine suction on opening move- ;.ments of said throttle, means controlled by restricts the admission of air; to a degree cle-,

the throttle for closing the valve as the throttle is closed and other means for moving the valve toward closed position while the throttle .remains stationary, said additional closing means being so constructed that the closing force exerted thereby on the valve is entirely independent of the position of the throttle.

2. A charge forming device for multicylinder engines,,comprising a mixture passage, means for supplying fuel and air thereto, a throttle, an

auxiliaryair valve for controlling admission of air to said mixture passage, said valve being operated by engine suction on opening movements of said throttle, means controlled by the throttle for closing the valve and other means operated automatically to move said valve toward closed position-undercertain operating conditions, said automatically operated means being constructed to exert a closing force on the valve which is independent of the position of the throttle controlled means whereby the closing effect of said automatically operated means may be constant while the position of the throttle controlled means varies or may be variable while the throttle controlled means remains in fixed position.

3. A charge forming device for multicylinder engines, comprising a mixture passage, means for supplying fuel and air thereto, a throttle, an

auxiliary air valve for controlling admission of air to said mixture passage, said valve being operated by engine. suction on opening movements of said throttle, manually operable means for closing the valve, and gravity actuated means operable under certain operating conditions for -moving the valve'toward closed position, said through, a spring for normally closing said valve,

manually operable means for preventing the closing of said valve bythe spring, and other means independent of the spring and said manually operable means for closing said valve under certain operating conditions.

5. A charge forming device for internal combustion engines comprising a secondary mixing chamber, a primary carbureting. means adapted to deliver a primary mixture of fuel and air to said secondary mixing chamber, a secondary air passage supplying air to said secondary mixing chamber, a main air valve controlling the admission of air to both said primary carbureting means and secondary mixing chamber, a suction operated valve in said secondary air passage for controlling the fiow therethrough, and gravity operated means operable to move said last mentioned valve toward closed position to a degree determined by the engine-suction. 6. A charge forming device for intemal' combustion engines comprising a mixture passage,

means for supplying fuel and air thereto, a throttle, an auxiliary air valve controlling admission opened on opening movements of the throttle, a dash pot for retarding opening movements of said auxiliary air valve but constructed to exert no closing efl'ect on said valve and a weight operable to move said air valve toward closed position independently of the dash pot.

7. A charge forming device for internal combustion engines comprising a mixture passage,

' means for supplying fuel and air thereto, a throttle, an auxiliary air valve controlling admission of air to said mixture passage and adapted to be opened on opening movements of the throttle, a dash pot for retarding opening movements of said auxiliary air valve but constructed to exert no closing effect on said valve, an arm secured to the shaft of said valve and having a one way connection with the dash pot piston whereby the valve is permitted to move toward closed position independently of the dash pot, and a weight secured to the valve shaft and adapted to move the valve toward closed position.

8. A charge forming device for internal combustion engines comprising a secondary mixing chamber, a primary carbureting means adapted to deliver a primary mixture of fuel and air to said secondary mixing chamber, a secondary air passage supplying air to said secondary mixing chamber, a main air valve controlling the admission of air to both said primary carbureting means and secondary mixing chamber, manually and suction operated valves in said secondary air passage for controlling the flow-of air therethrough and gravity operated means for moving the, suction operated valve toward closed position under certain operating conditions inde pendently of the positionof the manually operable valve.

9.,A charge forming device for multicylinder engines, comprising a mixture passage, means for supplying fuel and air thereto, a throttle, an aux=- iliary air valve for controlling admission of air to said mixture passage, said valve being operated by engine suction on opening movements of said throttle, means controlled by the throttle for closing the valve as the throttle is closed, means operable on reduction of engine suction to move the valve toward closed position while the throttle remains stationary and constructed so as to exert the same closing force in any one position of the valve, irrespective of the position of the throttle.

10. A charge forming device for multicylinder engines, comprising a mixture passage, means for supplying fuel and air thereto, a throttle, an auxiliary air valve for controlling admission of air to said mixture passage, said valve being operated by engine suction on opening movements of 'said throttle, means controlled by the throttle for closing the valve as the throttle is closed, means operable on reduction of engine suction to move the valve toward closed position while the throttle-remains stationary and constructed to exert a progressively increasing closing force as the valve moves toward closed position.

11. A charge forming dezice for multicylinder engines, comprising a mixture passage, means for supplying fuel and air thereto, a throttle, an auxiliary air valve for controlling admission of air to said mixture passage, said valve being operated by engine suction on opening movements of said throttle, means controlled by the throttle for closing the valve as the throttle is closed, means operable on reduction of engine suction to move the valve toward closed position while the throttle remains stationary, said means comprising a weighted arm movable with the valve and adapted to be moved from a position in which it extends in a substantially horizontal plane when the valve is closed toward a position in a vertical plane as the valve opens, whereby the closing force exerted by the weight decreases as the valve moves toward open position.

12. A charge forming device for internal combustion engines comprising a mixture passage, means for supplying fuel and air thereto, a suction operated auxiliary air valve for admitting air to the mixture passage, a spring for normally holding said valve closed, a throttle for controlling the flow through the mixture passage, means operable by the throttle as it is opened to prevent the spring from holding the valve closed when the throttle is not in closed position, and other means operable independently of the spring and the throttle for moving the valve toward closed position under certain operating conditions.

FRED E. ASELTINE.

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