US2208317A - Carburetor for internal combustion engines - Google Patents

Description

July 16, 1940. BECK CARBURETOR FOR INTERNAL COMBUSTION ENGINES Filed Feb. 16, 1937 4 5 2/ u u r 1 a... m Vi l /2 M JW w a 24 m. n F NUH b -M L Patented July 16, 1940 UNITED. STATES CARBURETOR FOR INTERNAL COMBUSTION ENGINES- Ludwig Beck, Berlin, Germany, assignor of one:

third to Ludwig Bertele, Berlin-Steglitz, Germany, and one-third to Alwin Dusterloh,

Sprockhovel, Germany Application February 16, 1937, Serial No. 126,039 In Germany February 18, 1936 3 Claims.

This invention relates to an improved carburetor for internal combustion engines, especially for such internal combustion engines as are employed for driving vehicles. This improved car- -,1 buretor is distinguished by its particularly low consumption of fuel without impairing in any way the flexibility with which the speed of the motor or engine follows the changes in the position of the throttle valve.

The invention is illustrated diagrammatically and by way of example in the accompanying drawing, in which- Fig. 1 shows a longitudinal section through a simple carburetor constructed according to the invention;

Fig. 2 is a similar representation showing a modified constructional form of the carburetor and drawn on an enlarged scale relative to Fig. 1;

Fig. 3 is an exterior view of the members connecting the throttle valve and the air valve of the carburetor shown in Fig. 2; and

Fig. 4 is partly an exterior view of, and partly a section through, a more complete carburetor vcorresponding generally to the one shown in Fig. 1.

Referring first to the diagrammatic representation in Fig. l, in this figure all parts which do not pertain to the invention have been omitted, as

.the drawing is merely intended to disclose the fundamental principle of the invention. In this figure of the drawing, the numeral l denotes the carburetor channel which is provided with the known constriction 2 into which extends the nozzle 3 which communicates with the'fioat carsing (not shown) by means of a passage 4. The

sectional area of the passage through which the nozzle is supplied with fuel is so small that the nozzle 3 receives only such an amount of fuel as suffices for the lower range of speed of the motor. There is, however, provided another nozzle 5, which extends as a separate member into the carburetor channel I and communicates with two passages 6 and l, of which 6 connects the nozzle 5 with the fuel supply passage 4, whereas I connects said nozzle with an aperture 8 opening to the atmosphere and which serves for the admission of air and lies above, and considerably remote from, the fuel-level a-'o.

The aperture 8 is so ground as to present a flat face and stands behind the valve plate 9 which is secured to the shaft ll] of the throttle valve ll. When this valve is open, the aperture 8 is fully uncovered, but when the throttle valve is being closed, it closes the aperture 8 to a corresponding extent, whereby also the air entering into this aperture is correspondingly throttled.

The invention makes use of the principle that a nozzle connected with a fuel supply passage, as well as with an air-supply passage, sucks in and delivers a mixture of these fluids, and thatthe contents of the fuel in the mixture will be the larger, the more the entrance of air is impeded. According to the present invention, said principle is utilized in such a manner that the nozzle 5 supplies fuel only in the range of the higher speeds, which in the case of vehicles, for instance, may be a speed of from 40 to km. per hour. In the lower speed ranges, the motor receives fuel through first mentioned nozzle 3 which is inserted into the suction channel as a separate member, the sectional area of which is so small (say about one-half of the sectional area of a normal carburetor nozzle) that it can supply the motor with fuel in a sufficient amount only up to that range of speed in which the supplemental nozzle commences to become active. One succeeds in this way (it being presupposed that the valve plate 9 is shaped suitable to the purpose intended) in adjusting the supply of fuel from the carburetor to the motor in the higher range of speed (in which normal carburetors operate uneconomically) accurately to the actual necessary consumption of fuel by the motor. It is, therefore, possible to attain in normal driving conditions savings of from 15% to 25% in com-- parison to the usual carburetors without impalring in the least the braking capacity and the acceleration capacity, in that these capacities depend chiefiy upon the design of the nozzle 3 which, in the lower range of speed or in the case of a sudden closure of the throttling valve (brakingby compression), acts as a normal carburetor nozzle, the action of which in this manner is not affected by the supplemental nozzle 5 because this nozzle can supply fuel solely in the higher ranges of speed. In the lower speed ranges the active vacuum at the nozzle 5 is so slight that it is insufficient to suck the fuel upwards from the deeply located fuel level a--b to and into the chamber It, by the intermediary of which the nozzle 5 and the passage 6 communicate with one another. If the vacuum active'at the nozzle 5 is increased by opening the throttle-valve H, the delivery of the fuel by and through said nozzle will be restricted because of the fact that air enters into the chamber I2 through the passagel, whereby the amount of fuel sucked in is prop erly regulated.

In orderv to adjust the carburetor correctly, the

chamber I2 is equipped with an air bleed passage,

adapted to be closed by a threaded valve, the head l3 of which is connected with a lever M by means of a clip l5. The free end of said lever is connected with a wire cable (not shown) terminating at the instrument panel of the car. The valve 13 can be closed by pulling at the above-mentioned wire cable, whereby a temporary excess of fuel is supplied in case the driver should desire a rapid acceleration of his car. Readjustment for winter condition, driving uphill, and the like, is effected by a corresponding readjustment of the lever clip 15 relatively to the head of the valve [3.

The supplemental nozzle 5 need not be arranged ahead of the throttling valve Ii, but may be located behind it with respect to the direction of flow of the air. sucked into the carburetor channel. A modification designed in this manner is shown in Fig. 2, in which if) denotes the carburetor channel which is contracted at the two portions I! and I8, of which one lies ahead of the throttling valve I9 and theother lies behind it. Two nozzles are provided, of

which one extends into one contracted portion I? of the carburetor passage and the other extends into the other contracted portion I8 thereof. The lower nozzle 23 is the one which lies ahead of the throttle valve I 9 with respect to the direction of flow of the air sucked in. Said lower nozzle is similar in design to commercial carburetor nozzles and consists of the tube 20 and the hood 2| which is screwed onto said tube 20. The tubular, portions of these members 20 and 2| form twoconcentric annular spaces, of which the outer one communicates with the passage 22 through which air is supplied into said outer space. The sectional area of the nozzle 7 formed by the said members 20 and 2! is so reto run in the lower speed range, and is the only at the nozzle 24 in Fig. 2).

stricted that the amount of fuel which can pass through it is only sufficient to enable the motor feature by which the nozzle 23 is distinguished from the commercial constructional forms.

Into the other contracted portion of the carburetor passage l6 extends the nozzle 24, which communicates with two passages, of which the passage 25 extends downwardly to below the fuel level a-b and is at its lower end connected with the fuel supply passage 26. The other upper passage 21 leads to a threaded valve 28 and to an aperture 29 which,co-acts with a valve plate 30 that is rotatable on a pivot 3| and is connected with the shaft of the throttle valve H by means of a link 33 and an arm 34. These members (30, 33, 34) are particularly well shown in Fig. 3, from which it appears that the valve plate 30 is wedge-shaped and is provided with an oblong tapered slot 36, by which the opening 29 is gradually closed as the throttle valve is opened.

The valve plate 30 acts, therefore, reversely to the valve plate 9 of Fig. 1. This is necessary because, when the throttle valve is closed, the vacuum present ahead of the same (that is to say, at the nozzle Sin Fig. 1) is reduced; but is increased behind the throttle valve (that is to say, When the throttle valve is closed, the highest vacuum becomes effective at the nozzle 24 and, therefore, enough air must enter through the passage 21 so that no fuel is sucked in.

The same is true of the lower speed range of the engine (slightly opened throttle valve). For this reason the sides of the slot 36 extend at first parallel to one another so that the valve plate 30 leaves the aperture 29 open for an angle of turning of about 20% of full throttle opening. Only when the throttle valve has been further opened, the valve plate 30 commences to cover the slot 36 gradually more and more, whereby a correctly regulated determination of the amount of fuel sucked in through the nozzle 24 is rendered possible. .In the low speed range, the motor is supplied with fuel exclusively by means of the nozzle 20-23.

Fig. 4 shows a thoroughly perfected carburetor of a type, the principle of which has been disclosed in Fig. l, the device being seen in the direction indicated by the arrow P in Fig. l. The float receptacle 3], which is designed as usual, communicates with the nozzle 38, which is constructed in about the same manner as the nozzle Elle-23 of Fig. 2, the connection being established by the passage 39 which supplies fuel also to the supplemental nozzle 40. The nozzles 38 and 40 extend into the carburetor channel All which tapers from one end to the other and both nozzles are located ahead of the throttle valve 42. Thenozzle 40 communicates also with the air passage 43 which has a branch 44, at the outer end of which is arranged the valve plate 45 which is firmly attached to the shaft 46 of the throttle valve. The more the throttle valve is opened, the more the branch M will be opened by the slide 45. The upper end of the air passage 43 is likewise closed by a valve plate 41, which is designed similar to the slide 30 (Fig. 3) and serves for regulating the carburetor to the proper operative condition. .The valve plate 41 is rigidly connected with an arm 48 having at its free end an eye 49 for connection with a wire cable, the other end of which leads to the instrument panel of the car, whereby it is rendered possible to close the passage 43 partially or completely, in order to produce temporarily an increased acceleration of the motor.

The carburetors described on the preceding pages can be equipped, of course, with the usual accessories as, for instance, an auxiliary carburetor. The carburetor shown in Fig. 4 has the adjusting screw 50 to be used for adjusting the idling mixture when the motor is running without load.

I claim:

1. Ina carburetor, a casing including a mixing chamber, a throttle valve in said chamber, normal speed and high speed fuel nozzles projecting into said chamber, means for supplying fuel at a predetermined level to said nozzles including a passageway leading to said high speed nozzle, a valve for admitting air to said passageway above the level of fuel therein, said valve being closed at normal speed, a second valve for admitting air to said passageway above the level of fuel therein, means for adjusting said second valve so that the amount of air admittedthereby is sufficient to prevent fuel from being supplied to said high speed nozzle at normal speed, and means interconnecting the first said air admitting valve and said throttle valve whereby the first said air admitting valve is opened only after said throttle valve has been opened a predetermined extent and progressively further opened as the throttle approaches wide open position.

2. In a carburetor, a casing including a mixing chamber, a main fuel nozzle projecting into said chamber, a throttle valve, a high speed fuel I nozzle projecting into said chamber, means for supplying fuel to said nozzles, air venting means for controlling the supply of fuel. through said high speed nozzle rendering the same inoperative to deliver fuel to the mixing chamber while idling and unresponsive to successively greater throttle openings until a predetermined throttle opening is reached, and additional valve means for regulating a supply of air to said high speed nozzle operated thereafter in accordance with the throttle opening to progressively decrease the rate at which the delivery of fuel from said high speed nozzle increases with increased throttle openings.

3. In a carburetor, a casing including amix ing chamber, a main fuel nozzle projecting into said chamber, a throttle valve, a high speed fuel nozzle projecting into said chamber, means for supplying fuel to said nozzles, means including a manually adjustable air valve for controlling the admission of air to said high speed nozzle and thereby the delivery of fuel from said high speed nozzle so that at any throttle opening between the idling position and a predetermined partially open position no fuel is delivered from said high speed nozzle, and means including a second air valve mechanically coupled with the throttle valve and effective after the said predetermined throttle opening is passed for progressively admitting air to said high speed nozzle and thereby decreasing the efiect of successively greater throttle openings on the sup- LUDWIG BECK.

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