US1985712A - Carburetor - Google Patents

Description

Dec. 25, 1934. 0 A ET AL 1,985,712-

cpgmunmon Filed Nov. 29, 1929 2 Sheets-Sheet 1 I I8 0 o o 0 17 a I3 3 I9 a ll 2: 2o

INVENTOR5 FREDERICK 0.5ALL AND BYTHOMAS M. BALL...

ATTORNEY Dec. 25, 1934.

r. 0, BALL ET AL CARBURETOR Filed Nov. '29, 1929 2 Sheets-Sheet 2 "Ill/6 AND v fl' j ATTORNEY INVENTOR-S FREDERICK 0. BALL BALL BY THOMA$ M.

Patented Dec. 25, 1934 UNITED STATES:

CARBURETOR Frederick 0. Ball and Thomas Detroit,

M. Ball, Mich.

Application November 29, 1929, Serial No. 410,581

3 Claims. (01. 261-51) This invention relates to an improved internal combustion engine carburetor.

The main objects of this invention are to provide an improved carburetor for internal combustion engines; to provide a method for controlling the proportion of fuel and air in the fuel mixture supplied to the combustion chamber of an engine so as to maintain a substantially uniform fuel richness, primarily by the carburetor suction while such suction is sufllcient to supply quantities of fuel. substantially in direct proportion to its intensity and to thereafter build up the richness of the mixture by injection under constant and uniform pressure from an external source; to provide an improved method for controlling the richness of a fuel mixture after the normal carburetor suction has been reduced by air supplied to the mixing chamber; and to ing throttle.

injecting fuel buretor suction to operate as the dominant factor in extracting fuel from the nozzle when the normal carburetor of air fed to the mixing chamber and to permit the injector to operate asthe dominant factor when the normal carburetor suction'becomes insumcient to-keep-up the richness of the fuel mixture; to provide apparatus for metering the flow of fuel to thenoz'zle in correspondence with the position of the throttle during the stage in which injection by external force is the predominant factor in controlling the richness of the mixture so as to maintain the richness within predetermined limits; to provide a nozzle of this kind which is adapted to thoroughly'atomize the fuel; and to provide improved means in a carburetor for obviating the by-pass and associated apparatus, heretofore required to deliver fuel above the butterfly valve of a carburetor at low carburetor suction.

An illustrative embodiment of our invention is shown in the accompanying drawings, in 6- 20 Fig. 6 is a fragmentary section showing a metering valve in a wide open position.

Fig. l is a fragmentary section showing a metering valve in an intermediate position.

Fig. 8 is a fragmentary section showing a me- 25 tering valve in a slightly open position.

In the form shown, our improved carburetor comprises a mixing chamber, fuel reservoir and throttle, all of standard construction, and apparatus for metering the flow of fuel from the 3 reservoir in a predetermined relation to the throttle adjustments. A nozzle in sure 'for feeding fuel from the nozzle independently of the normal carburetor suction.

In the illustration shown, the fuel reservoir 1 has an inlet 2 through which fuel is supplied under the control of the inlet valve 3 which is actu-' ated by a float 4. The float 4 and valve 3 retain the fuel at a predetermined level in the reservoir.

Communicating with the bottom of the reservoir 1 is'a passage 5 which extends through the walls of the carburetor into the interior thereof.

A tubular nozzle Ghaving a fixed end orifice '7 and a plurality of fixed side orifices 8 is located in the mixing chamber 9 of the carburetor in 7 communication with the passage 5. The mixing chamber 9 is provided with a Venturi throat 10 which has a constricted portion substantially at the elevation of the side apertures 8 of the nozsupplied per minute with awide zle, thereby causing the region of maximum suction to exist substantially at the apertures 8.

Extending axially of the nozzle 6 is a power jet or injector 11 which is connected by tube 12 with an external source of air or other suitable gas under a uniform pressure. The upper end of the injector has a constricted orifice 13 through which the air is discharged at a high velocity, thereby feeding fuel from the interior of the nozzle, 6 to the mixing chamber 9 of the carburetor independently of the normal suction in themixing chamber. a

The throttle 14 has a shaft 15 which is rotatably mounted in apertured bossesformed on the walls of the mixing chamber. The left end of the shaft 15, as viewed in Fig. 1, is provided with a crank lever 16 which is operatively connected by a link 34 with an accelerator, or other manual control mechanism, not shown in the drawings. Rigidiy mounted on the right end of the pin 15 is a crank lever 350m which a valve stem 17 is pivoted at 18. The valve stem 1'7 is slidably mounted in an aperture 19 at the top of the fuel reservoir and extends into a metering orifice 20 which communicates with the passage 5. The lower end of the valve' 17 has a pin 21 of uniform, reduced diameter and the section 22 of the stem which is adjacent the pin 21 is tapered so as to form a gradually opening orifice 20. Rotation of the throttle 14 causes the valve stem 17 to reciprocate.

In operation, when the throttle of a carburetor embodying our invention is wide open the pin 21 is fully retracted from the metering orifice 20 as shown in Fig. 6. This stage of the operation is represented at the point 23 on the curve A shown in Fig. 4 where the number of cubic feet of air flowing through the carburetor per minute is comparatively large and the suction created is strong enough to feed the fuel from the side orifices 8 of the nozzle which are above the fuel level therein.

Curves B and C of Fig. 4 represent the mixtures which would be produced by the carburetor suction alone and by the injector alone respectively. The mixture ratio represented at 23 on curve A is the sum of the percentages of fuel represented at 24 on curve B and 25 on curve C.

As the speed of the engine is reduced by an increasing load, the mixture ratio produced by the carburetor suction alone decreases from 24 to 26 on curve B. At 26 the suction finally becomes too low to raise the gasoline in the nozzle to the side orifices 8. h

The mixture ratio due to injection alone is very small at 25 but it increases at a definite rate as the engine rate is reduced. This rate of increase offsets the decrease in the mixture ratio which is produced by the carburetor suction and maintains a uniform fuel mixture until very low engine speeds are reached. The mixture ratio which is produced by the injector alone increases rapidly at very low speed operation of the engine and forms a rich mixture which is'required at very low engine speed.

It willbe noted that the suction curve 24 and the injector curve 25 cross at 2'7 where they contribute equally in producing the final mixture ratio. Suction is the dominant factor influencing the mixture ratio at speeds greater than that represented at 27 and injection is the dominant factor at lower speeds.

Another condition exists when the throttle is partly closed and the engine is called upon to deliver only a part of its full power, as for example,

when an automobile is driven at intermediate speeds on good roads. Under these conditions it is found that the percentage of fuel in the mixture must be reduced to obtain the best economy.

In our improved carburetor, the above condition is met by providing the pin 21 on the end of the valve 1'1 which is extended into the orifice 20 when operating with a partly open throttle and under light loads. The curve 28 in Fig. 5 represents a desirable economy mixture which is obtained by restricting the orifice 20 by the pin 21.

If no change occured in this restriction at very low speeds the mixture ratio would increase very rapidly, as shown by the dotted line extension 29 of the curve 28. This condition is corrected by the conical shaped part 22 of the stem 1''! which is so adjusted at the entrance of the orifice 20 as to give the desired mixture ratio 30 when the throttle is set for idling. The conical part is shaped so as to open the orifice gradually as the throttle is opened, thereby giving correct gradations of the mixture between the'idling mixture shown at 30 and the mixture represented at 28. A power mixture represented by the curve 23A on Fig. 5, which is substantially the same as the curve 23 of Fig. 4, is produced when the pin 21 is completely withdrawn from the orifice 20. The apparatus may be constructed to withdraw the pin 21 at any desired speed.

Although but one specific embodiment of this invention has herein been shown and described, it will be understood that various changes including the size, shape and arrangement of parts, may be made without departing from the spirit of our invention and it is not our intention to limit its scope other than by the terms of the appended claims.

We claim:

1. A carburetor comprising a mixing chamber, a throttle and a fuel reservoir, a nozzle in said mixing chamber having a fixed end orifice and a plurality of fixed side orifices and communicating with said reservoir through a passage in said carburetor having a metering orifice therein, said side orifices being adapted to feed fuel to said mixing chamber by the normal suction therein, an injector having an external source of force in said nozzle for feeding fuel through the end orifice of said nozzle independently of the suction in said mixing chamber, a valve in said metering orifice, and mechanism connecting said valve with said throttle for automatically regulating the fiow of fuel to said nozzle and adapted to gradually decrease'such flow only when the normal suction in said mixing chamber is reduced by the action of said throttle below that intensity required to feed fuel in proportion to the air fiow in said mixing chamber so as to control the richness of said- .let of said nozzle independently of said suction and adapted to maintain the fuel ratio of the mixture in said mixing chamber at a predetermined value when said suction is incapable of feeding suflicient fuel from said side apertures to maintain said fuel ratio.

mamta 3 3. A carburetor including a fuel reservoir and orifice adjacent the end outlet thereof adapted a mixing chamber, a Venturi throat in said mix-' to feed fuel through said end outlet for maintaining chamber, a nozzle in said mixing chamber ing the fuel ratio of the mixture in said mixing having a substantially unrestricted end outlet and chamber at a predetermined value when said suc- 5 having aseries of side apertures located substantion is incapable of feeding sufllcient fuel from tially at the maximum restriction of said Vensaid side apertures to maintain said fuel ratio. turi throat for feeding fuel into said mixing 4 chamber under the influence of the suction there- FREDERICK 0. BALL. in, and an injector jet in said nozzle havingan THOMAS M. BALL.

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