US 1729382 A
Description (OCR text may contain errors)
Patented Sept. 24, 1929 UNITED STATES PATENT ()FFICE CARBURETOR Application filed January 21, 1928, Serial No. 248,546, and. in Germany December 3, 1926.
If a carburetor be considered in its simplest form, that is to say, with a single nozzle in communication with the constant level float chamber and opening out in the Venturi tube of the carburetor an excessively poor mixture is produced on the slow movement of the motor and on acceleration of the motor an excessively rich mixture is produced which is so disproportionate as to require the control of carburation according to the speed of the motor. Such is the object of the invention.
According to the invention the nozzle for the Volatile liquid is combined with an envelope, in such manner that between the nozzle and the said envelope there is formed an air chamber which is in communication with the atmosphere, and is provided with two orifices disposed in opposite positions in the nozzle to effect communication between the air chamber and the nozzle above the level of volatile liquid in the nozzle, the said orifices being provided diametrically opposite one another in such manner that their diametric central axes coincide and the streams of air entering the nozzle tube through the said orifices impinge upon each other in a direction normal to the central axis of the said nozzle tube close to the nozzle outlet and immediately above the level of the volatile liquid so as to produce, during the suction stroke, air currents which form a screen or obturator offering a resistance to the evaporation of the volatile liquid, which resistance at slow speeds of the motor is negligible and increases with an increase in the speed of the motor, whereby the richness of the mixture supplied to the motor is automatically regulate-d.
According to the invention, moreover, means are provided for varying the conditions of air supply at different altitudes.
The accompanying drawings represent by way of example a construction of carburetor according to the invention.
Figure 1 is a vertical section of a nozzle provided with means for producing obturation of the supply of volatile liquid by means of an air screen.
Figure 2 is a diagram in horizontal section illustrating the manner in which the obturation by means of an air screen is effected.
Figure 3 illustrates in vertical section a construction similar to Figure 1 with means for the admission of a regulable air supply.
Figures 4 and 5 relate to modifications hereinafter specifically described.
The drawings represent all the parts necessary to the comprehension of the invention, leaving out those parts that are unnecessary for the purpose, such as the constant level float chamber, where these details are similar to those of known carburetors.
In the drawings 1 is the Venturi tube, 2 is the conduit for the volatile liquid from the constant level float chamber. The conduit 2 opens into a chamber 3 within an enlarged part which is provided with the screw thread at for the reception of the nozzle 5, the washer 6 being interposed between a flange at the lower end of the nozzle and the under face of the enlarged part referred to. A hollow and calibrated screw-threaded plug 7 for the volatile liquid is mounted within a cylindrical cavity 10 in the lower part of the nozzle, the
plug being provided with a calibrated orifice 8 and the chamber 3 being closed at its lower end by means of the screw threaded plug 9. The nozzle 5 carries concentrically a tube 11 having a flange 12 which is screw-threaded at 13 in the opening of the nozzle. At 14 is disposed a radial slot for the application of the concentric tube 11 in position.
The concentric tube 11 is provided with holes at 15, 16 oppositely disposed one to the other with their axes in coincidence, and at its lower part is provided with a conical face 17 which is applied upon a corresponding conical seat 18 in the lower part of the nozzle. At 19, 20 are providedtwo oppositely disposed orifices of relatively large diameter as a means of communication between the atmosphere and the annular chamber 21 forming an air acket around the concentric tube 11 of the nozzle.
The arrangement described comprises the essential features of the construction the operation of which is as follows The volatile liquid passing through the conduit 2 fills the chamber 3, and passes through the orifice 8 in the calibrated hollow plug 7 to form a level of liquid for example at mn below the orifices 15, 16 in the concentric tube 11. On the fall of pressure produced in the Venturi tube 1 by reason of the engine suction, simultaneously with the evaporation of the volatile liquid that is induced at the level mn, air is admitted through the orifices 15, 16 in two opposing currents which impinge upon one another and cause a whirling such as indicated at 22 (Figure 2) that is hereinafter referred to as pneumatic obturation.
If the motor operates at low speed this pneumatic obturation has negative or almost negative effects inasmuch as the currents of air admitted through 15, 16 are less energetic. Thus the suction acts almost exclusively upon the volatile liquid at the level m-n whose vapour has no obstacle in emerging through the opening of the nozzle, or in other words through the upper opening of the concentric tube 11, so that thus the carburation will be relatively rich.
If the motor operates at high speed, the greater the speed the greater will be the evaporation of the volatile liquid at the level m-n until it attains excessive proportions; but at the same time as the intensity of the currents of air penetrating through 15, 16 and the energy of the whirling 22 increases, this whirling produces an obstacle or screen which reduces the effects of suction upon the level of the volatile liquid m-n and at the same time produces a provision of air which attenuates the richness of the carburation. When the motor acquires a high speed the whirling 22 offers a considerable resistance and a provision of air proportioned to the volatile liquid induced by the suction, so that the richness of the mixture is maintained at normal proportions.
In order to obtain the effects explained it is of course necessary to effect the convenient regulation of the orifices 15, 16, because if they are too large the air would not be an obstacle suflicient to assure the operation of the motor at low speed and the mixture would be excessively poor for operation at higher speed. It will thus be understood that between the two extreme limits there exist conditions that are satisfactory for effective carburation at all speeds, and these conditions have accordingly to be determined and to be accepted according to the practical requirements of the motor.
In Figure 3 is illustrated acorrector device for the carburetor hereinbeforedescribed for the purpose of controlling the carburation at different altitudes. In this case the orifices 19 and 20 of the nozzle open into a chamber 23 to which a tubing 24 is connected which at one end is connected to the casing of a valve cock which have passages of a different calibre denoted by an indicator 25.
lVith this corrector the admission of air into the chamber may be graduated, and thus the admission of air through the orifices 19 and 20 and consequently the intensity of formation. of the whirling 22.
In Figure 1 there is illustrated a construe tion according to the invention in which is provided a nozzle for slow running of the motor. The air jacket provided at 26 communicates with theatmospl'iere at 27. The other elements are denoted by numerals identical with those of the figures hereinbefore described. At 28 is applied a valve or piston, at 29 is provided the suction conduit, and at 30-3O the body of the carburetor.
Figure 5 shows a construction to adapt the calibrated hole 8 to speeds slower than ordinary. This arrangement comprises a tube 31 within the central bore 32. It will be understood that the suction acts not only upon the part 8, but also exercises an effect upon the lower opening of the tube 31, which if the suction is very intense takes of the air which enters at 83 and passes through the orifices 3 1-, 35. This arrangement has, moreover, the advantage of proportionally reducing the consumption of volatile liquid at full speed of the motor inasmuch as by rea son of communication with the atmosphere the proportionality of the consumption is limited, notwithstanding that the calibre may be larger.
It will be understood that the carburetor of the invention may be constructed in a wide variety of forms.
I claim v 1. In carburetors for internal combustion motors, a nozzle tube, an envelope concentric with the said nozzle tube and forming an air chamber surrounding said tube in communication with the atmosphere, said nozzle having two orifices disposed diametrically opposite to each other therein close to the outlet thereof and immediately above the level of the volatile liquid therein, the said orifices having their diametric central axes coinciding in order that streams of air entering the nozzle tube thereby may impinge upon each other in a direction normal to the central axis of the said nozzle tube.
2. In carburetors for internal combustion motors, a nozzle tube, a concentric sleeve disposed around said nozzle tube and forming an air chamber which is closed at the upper end of the nozzle tube, said sleeve having orifices therein to permit the said air chamber to communicatewith the atmosphere and having two diametrically disposed orifices therein immediately above the level of volatile liquid therein and adjacent the outlet thereof, the said orifices having their diametric central axes in coincidence so that the streams of air entering the nozzle tube therethrough impinge upon each other in a direction normal to the central axis of the said tube.
8. In carburetors for internal combustion motors as specified in claim 2, the provision of a nozzle tube having at the upper end an outwardly extending flange to fit the sleeve and at the lower end a coned face to engage a coned seating in the lower closed end of the sleeve and formed with an axial boring in the closed end of the sleeve effecting communication with the nozzle tube, and a plug in the said boring provided with a calibrated orifice for the passage of volatile liquid to the nozzle tube.
4. In carburetors for internal combustion motors, a nozzle tube, a sleeve concentric with the said nozzle tube and forming therewith an intermediate air chamber, means for permitting the admission of air under regulation into the said air chamber, the said nozzle tube being provided near the outlet with two diametrically disposed orifices immediately above the level of the volatile liquid therein, the said orifices having their geometric central axes in coincidence so that the streams of air entering the nozzle tube impinge upon each other in a direction normal to the central axis of the said nozzle tube.
5. In carburetors for internal combustion motors as set forth in claim 4, a casing surrounding the lower end of the sleeve, said sleeve having orifices therein communicating with the said casing, a valve device connected with the said casing by a conduit and means on the said valve device for regulating the entry of air by way of the said conduit.
6. In carburetors for internal combustion motors, a nozzle tube provided near the outlet and immediately above the normal level of volatile liquid therein with two diametrically disposed orifices having their geometric central axes in coincidence, means having therein a chamber within which the said nozzle tube is disposed and forming an air jacket surrounding the said nozzle tube, means of communication between the said air jacket and the atmosphere, the said nozzle tube being provided with a central bore of enlarged diameter, a downwardly depending tube ex tending within the said bore of large diameter to form concentric chambers in communication at the lower end and means at the upper end of the outer concentric chamber e1.- fecting communication between the air jacket and the said chamber.