US2198100A - Carburetor device - Google Patents

Description

April 23, 1940. v. c. WORDEN 1 2,198,100 'c'ARBUREToR DEVICE Filed Feb. 19, 1957 j i ,l I Z7, Z n i /4 Z ,d Z /5 ,z5 /3 i 22223 /z Z 4 /o za Z/ Z 3a A 5 y 374 38,4

43 46 5 ==F%. 3? 38 l 4 v x 4Zv Tw 45 /q i 4 I a; 254 .3/ z l 4/ y 24/ 'v g F// 50 l a 4l l I f6 f5 V//A/ C. Wazaa/v INVENTOF l BY M L F/. 5

ATTORNEY.

Patented Apr. 23, 1940 UNITED l STATES CARBURETOR DEVICE Van C. Worden, Detroit, Mich., assignor to Carter Carburetor Corporation, St. Louis, Mo., a corporation of Delaware Application February 19, 1937, Serial No. 126,650

6 Claims.

This invention relates to carburetors for internal combustion engines and consists particularly in novel combination anti-percolation and so-called step-up or economizer means therefor.

It is well known that the fuel and air mixture which must be supplied to the cylinders of an internal combustion engine in order to produce the greatest power of which the engine is capable,

10 is substantially richer in fuel than the mixture which results in the greatest economy of operation. It is, therefore, desirable in carburetors of the above type to provide for an additional supply of fuel to.the main induction or mixture conduit l5 when the associated engine is subjected to increased power demands, or, in other words, is operating in the power range. 'Ihis additional supply should be restricted or cut off during socalled part throttle or economy range operation of the carburetor during which time the associated engine is developing substantially' less power than it is capable of producing. Means for enriching the mixture only as long as load conditions exist are known as step-up devices or economizers. When increased power is required of an automobile engine, the driver instinctively opens the throttle so as to attain the desired engine speed. Accordingly, the extra fuel may be supplied manually by movement of the throttle to a predetermined degree of opening, or by suction posterior to the throttle. Since the intake suction and degree of throttle opening are` closely related, varying, in general, in the inverse ratio, both types of step-up devices are considered broadly equivalent so far as the present invention is concerned.

Another problem in modern carburetor construction arises from the fact that such carburetors are ordinarily located immediately above the engine manifolds and-thus directly exposed to the heat thereof. This heat frequently causes fuel in the carburetor and, particularly, in the discharge passages thereof, to boil or percolate, the resulting gaseous bubbles passing out through the discharge nozzle and causing substantial quantities of unvaporized fuel to be spilled into the intake manifold. This condition occurs more readily immediately after a hot engine is stopped and results in loading which hinders re-start- 5@ ing of the engine, causes excessivecarbon deposits, and has other injurious effects until the excessive charge is dissipated.

Separate means have heretofore been suggested for solving both of the above described g5 carburetion problems. The step-up and economizer arrangements though, frequently, involving an opening between the mainA fuel supply system and the fuel reservoir in addition to the main metering orifice, have been ineffective as anti-percolating devices due to the relatively 5 small sized auxiliary fuel orifices used for this purpose and to the fact nthat the orifices were cut o or substantially restricted when the carburetor was inoperative. When an additional opening has been provided at the base-of th main` 10 fuel nozzle for releasing percolation bubbles, this opening was carried above the fuel level and, moreover, was usually completely cut off, so as not to affect the fuel mixture, except when the carburetor was inoperative and percolation most l5 likely to result.

An object of the present invention is to combine effective step-up and anti-percolating means in a simplified, unitary structure. v

A more detailed object is to provide a step-up 20 device of the above type, either suction or throttle operated and so constructed and arranged a's to function also as an anti-percolation instrumentality.

These objects and other more detailed objects 25 hereafter appearing are attained in the accompanying drawing in which:

Figure 1 is a vertical sectional view of a carburetor illustrating one form of the invention.

Figure 2 is a detailed section taken at 90 de- 30 grecs to Figure 1 and substantially on line 2-2 thereof.

Figure 3 is an enlarged sectional view taken on substantially the same plane as Figure 2-but illustrating a modification. 35

The carburetor illustrated in Figure 1 is in general of a more or less conventional type having a downdraft mixture conduit or barrel including air inlet horn i, venturi 2, mixing chamber 3, and outlet portion t, flanged as at 5- for attachment to riser portion 6a of intake manifold 6. A choke valve 'i is pivotally mounted in the air horn and a butterfly throttle valve t controls the outlet portion. VExtending acrosslthe venturi between the air horn and mixing chamber is a jet bar 9. A 45 crank is provided for manually opening the throttle by means of the usual throttle pedal and a return spring 56 closes the throttle when'the throttle pedal is released by the operator, as is the case when the carburetor is not in operation. 5g

Adjacent the barrel portion of the carburetor is a bowl l0 within which fuel is maintained-at a substantially constant level by needle valve mechanism H, controlled by float I2. Valve Il controls tting I3 for connecting the Acar- 5g.

buretor with a remote fuel tank, not shown.

Extending upwardlyl at an angle from bowl through jet bar 9 is a fuel discharge passage I4 communicating in its upper portion with the downdraft mixture conduit by means of laterally lmeans of this type are well known in the art, being illustrated in many patents, such as Chandler Patent No. 1,957,631 and Ball et al. Patent No. 2,108,281, and having been widely used for a number` of years on the B. B carburetors manufactured by applicants assignee. Extending downwardly through passage I4 is an idling tube lI6 communicating at its upper end with vertical passage I 'I leading downwardly to idle port I8 adjacent the throttle valve. 'Ihe usual idle 'adjustment needle is provided at I9.

A plug 20, threadedly secured near the lower end of passage |4 has a central aperture suiilciently large to care for the maximum liquid fuel requirements of the carburetor. beneath or anteriorto plug 20 at the base of passage I4 and connecting the passage with the fuel bowl is a second plug 2| having a substantially smaller bore than plug '20 and calibrated to supply only sufficient fuel for the economy range operation of the carburetor. The small chamber 22 between plugs 2li and 2| also communicates with the fuel in bowl I through upwardly facing opening 23 in boss 24,'this open- `ing terminating substantially beneath the normal fuel level :v -:c in vbowl I0. operatively associated with opening 23 is-a valve 25 which has a seat on the upper end of boss 24. Valve stem 26 is slidable within guide plug 21 secured in an apertured boss 28 projecting into bowl I0 from the carburetor barrel. The `v'alve is constantly urged downwardly by a coiled spring 29 seated at its upper end against guide plug 21.

Auiant boss 24 in bowl lo is a vertical, houow cylinder 30 having an internal bore which at its enlarged upper endslid'ably receives a closely' fitting, double piston 3| constantly urged upwardly by coiled spring 32 seating against the closed bottom of the cylinder. Secured to the upper portion of the stem 33 projecting from piston 3|v is a lateral arm 34 which at its opposite end loosely receives valve stem 26. Stem 26 has a'collar or key 35 at its upper extremity and above arm 34 whereby raising of this arm tends to raise the valve stem and valve 25.

The interior of cylinder 30 communicates with the carburetor mixture conduit posterior to throttle 8 through the suction connection 36. Piston 3| and valve 25 are accordingly controlled by spring 32 and the pressure difference on the upper and lower portions of piston 3|, the top of the piston being exposed to atmosphere in the fuel bowl. In other words, piston 3| and valve 25 are said to be responsive to suction posterior to the throttle.

In practice, spring 32 is made strong enough to hold valve 25 in its upper or non-restricting position whenever the carburetor or the associated engine is inoperative or the engine is subjected to power demands requiring more gasoline than can be supplied through, plug 2|. This condition of the valve may be maintained throughout any desired vacuum range, depending upon the characteristics of the particular carburetor and engine. In a well known installation, the vacuum step-up device is opened or rendered operative when the `suction prevailing in the intake manifold corresponds with not more than Secured arcaico to passage I4 through perforated plug 2| and also through the large, upwardly facing opening 23, the only restriction being at plug 20. At all other times when the intake suction may extend to a value corresponding with as high as 24 of mercury,-auxllia1y valve 25 will be closed for economy operation.

Chamber 22 between plugs- 20 and 2| is directly exposed to heat from the engine and manifold 6 through the metal of the carburetor body. 'I'his heat may cause fuel in chamber 22 to boil, forming bubbles which, according to well known principles of physics, tend to seek the easiest and most direct upward passage. Opening 23 is made substantially larger than the aperture ln plug and faces more sharply upwardly than passage I4, in this case being vertical, so as to readily release the percolation bubbles in chamber 22, provided valve is lifted. Obviously, the antipercolatlng device will be effective when the associated engine is inoperative, at which time percolation constitutes the greatest problem, due to the upward pressure applied to piston 3| and the valve by spring 32.

In Figure 3 valve 25, controlling the auxiliary fuel supply orifice 23, has a valve stem 26a extending upwardly through the fuel bowl cover and guided by an apertured boss 36 depending therefrom. At the upper end of stem 26a is a yoke 3l having arms 38 and 39 bent over at their upper ends to form lips 38a and 39a. Rigidly secured to throttle shaft 8a is an arm 40 connected by means of a link 4| to one endv of lever 42 pivoted at 43 to' post 44 on the bowl cover. The accelerating pump piston rod 45 is secured to the other end of lever 42 by means of a short link 46. The accelerating pump piston 4'I reciprocates in a cylinder 48 within the bowl provided with the usual'inlet check 49 and outlet check 50 controlling communication between the pump cylinder and the bowl and the cylinder and the mixture conduit, respectively.

Lever 42 extends immediately adjacent yoke 31 and beneath lips 33a and 39a thereof and is disposed to engage lip 38a to open valve 25 when the throttle is fully closed, as shown. When the throttle is fully opened, lever 42 engages lip 39a so as to lift yoke 31 and valve 25. Ordinarily, when the associated engine is inoperative, thottle valve 6 will be closed and valve 25, accordingly, i opened so as to release percolation bubbles. Similarly when the associated engine is subjected to a heavy load and the carburetor isvoperating in its power range, the throttle valve will ordinarily be substantially fully opened so as to withdraw valve 25 from step up opening 23 to supply additional fuel to the discharge passage I4. During part throttle operation valve 25 will be held against its seat by coiled spring 29.

In each case, valve 25 preferably functions so as to gradually vary the auxiliary fuel supply, but the orifice for releasing percolation bubbles should be fully open when the engine is inoperative. Both the manual and suction controlled step-up devices are conventionally arranged to be closed when the carburetor is operating with the throttle partially open, tha\t isin the economy range, when relatively high suctions prevail posterior to the throttle, regardless of speed, and to be opened during substantially full throttle operation, that is, in the power range, when relatively low suctions exist in the carburetor. The return spring normally insures the closed position of the throttle whenever the carburetor is not in operation.

The invention is not limited to the structure as shown, but may be modified in various respects as will occur to those skilled inthe art, and the exclusive use of all such modifications as come within the scope of the appended claims is contemplated.

I claim: 4

l. In a carburetor having a downdraft mixture conduit, a throttle in said conduit, a fuel chamber, an upwardly extending fuel passage connecting said chamber and said conduit, said passage communicating with said chamber through an upwardly facing orifice, a valve in said orifice having a projecting actuator, a lever pivoted adjacent said actuator and operated by said throttle, said actuator havingl a branch on each side of the pivotal support of said lever and disposed to be moved by said lever so as to open said valve when said throttle is closed or opened beyond a predetermined degree, and means for closing said valve in intermediate positions of said throttle, said orifice and said valves being `constructed and arranged so that when said valve is open, the free space in said orifice is suicient to permit release of gas bubbles formed a therebeneath in said passage. g

2. In a carburetor for an internal combustion engine, a mixture conduit, a fuel reservoir,an

upwardly inclined fuel discharge passage communicating with said reservoir by means of an orifice and extending into said conduit, said passage also communicating with said reservoir by means of a second upwardly facing orifice directly above the base of said passage, a valve for said second orifice, means for moving said valve to its most restricting position when said carburetor is being operated in its economy range, and means for urging said valve open when the carburetor is being operated in the power range and. also when the carburetor is not in operation, said second orifice 'and said valve being constructed and arranged so that when said valve is open, the free space in said orifice is suflicient to permit release of gas bubbles formed therebeneath in said passage.

3. In a carburetor for an internal combustion engine, a mixture conduit, athrottle valve therein, a constant level fuel reservoir, manual means for opening said throttle and a return spring for closing the same,'a fuel passage extending upwardly at an angle from said reservoir and discharging into said conduit anterior to said throttle, said passage communicating with said reservoir through a metered orifice, there being a second, upwardly facing orifice in -the wall of said passage directly above the base thereof, the carburetor above said second lorifice being constructed to provide substantially a direct passage to space above the fuel level for the release of gas bubbles formed in said passage beneath said second orice, a metered restriction in said passage posterior to said second orice, a valve `for said second orifice, said valveand said orifice being constructed and arranged so that when said valve is open, the free space in said orice .is sufficient to permit release'of gas bubbles formed therebeneath in said passage, means for moving saidvalve to its most restricting position when the carburetor is operating under conditions with said throttle open less than a predetermined degree, and means for urging said valve fully open under conditions when the carburetor is not in operation.

4. In a carburetor for an internal combustion engine having a throttle and a fuel reservoir, a

member operable by said throttle, a main fuel passage having communication with said reservoir through a calibrated orifice and a second, upwardly facing orifice, both below the normal fuel level in said reservoir, a valve for said second orifice, and a. valve operating device between said throttle operated member and said valve constructed and arranged to open said valve when said throttle is fullyl closed and to close said valve when said throttleA is opened less than a predetermined degree, the free space in said orifice being of suicient size, when said valve is open,to permit the escape of gas bubbles formed therebeneath in said passage.

5.-In a carburetor for an internal combustion engine, a mixture conduit, a throttle therein, a fuel chamber, an upwardly inclined fuel passage discharging into said conduitand communicating with said chamber through an upwardly facing, submerged orifice directly above the base of said passage, a metering restriction in said passage posterior to said orifice, a valve for said orifice, and means operated by said throttle for closing said valve when said throttle is opened less than a predetermined degree and for opening said valve when said throttle is fully closed or opened beyond said degree, said orifice `and said valve being constructed to provide sufficient free space in saidorifice, when said valve is open, Ifor the release of gas bubbles in said passage.

6. In a carburetor for an internal combustion engine, a mixture conduit, a throttle valve therein, a constant level fuel reservoir, manual means for opening said throttle and a return spring for closing the same, a. fuel passage extending upwardly at an angle from said rservoir and discharging into said conduit anterior to said throttle, said passage communicating with said reservoir through a metered orifice, there being a second, upwardly facing orifice in the wall of said passage substantially at the base thereof, the carburetor above said second orifice being constructed to provide substantially a direct passage-to a space above the fuel level for the release-of gas bubbles formed in said passage beneath said second orifice, a metered restriction in said passage posterior to said second orifice, a valve for said second orifice, said valve and said orifice being constructed andy arranged so that when said valve is open, the free space in said orifice is suflicient to permit release of gas bubbles formed therebeneath in said passage, means responsive to suctionposterior'to said throttle for moving said valve to its most restricting position at relatively high suction, and means. for fully openingv said valve when there is no suction posterior to said throttle.

' vAN c. WORDEN.

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