US3003755A

US3003755A - Adjustable devices for metering and emulsifying gaseous and liquid substances

Info

Publication number: US3003755A
Application number: US853202A
Authority: US
Inventors: Peras Lucien
Original assignee: Renault SAS
Current assignee: Renault SAS; Regie Nationale des Usines Renault
Priority date: 1958-11-28
Filing date: 1959-11-16
Publication date: 1961-10-10
Anticipated expiration: 1978-10-10
Also published as: GB907576A; DE1145857B; FR1216528A; OA01316A

Description

Oct. 10, 1961 L. PERAS ADJUSTABLE DEVICES FOR METERING AND EMULSIFYING GASEOUS AND LIQUID SUBSTANCES Filed Nov. 16, 1959 Fig. 1

United States Patent M 3,003,755 ADJUSTABLE DEVICES FOR METERING AND EMULSIFYING GASEOUS AND LIQUID SUB- STANCES Lucien Pras, Billancourt, France, assignor to Regie Nationale des Usines Renault, Billancourt, France Filed Nov. 16, 1959, Ser. No. 853,202 Claims priority, application France Nov. 28, 1958 7 Claims. (Cl. 261-71) This invention relates to a device for metering and emulsifying gaseous and liquid substances, and it is the specific object of the present invention to provide a device of this character which is intended more particularly for feeding internal combustion engines.

Low-pressure feed devices for internal combustion engines are known wherein the pressure is produced by a feed pump of the blade, gear or centrifugal type, the output being adjusted by throttling of the fuel stream under pressure. A known system proposed by the applicant and utilized for fuel pressurizing purposes comprises on the one hand a conventional-type feed pump, for example of the self-regulating type using a calibrated spring andiresponsiveto a lever actuated by a cam solid with the camshaft of the engine, and on the other hand a centrifugal pump mounted in series therewith. This centrifugal pump may be adapted to its specific functions by resorting to certain arrangements. Thus, to prevent the leakages occurring at the bearings of the centrifugal pump from becoming permanent irrespective of the pump speed, the fuel inlet is disposed not centrally of, but at some distance from the centre of, the rotor. Moreover, the fuel leaking through the pump bearings when the pump is driven at low speed is led into a pump chamber connected through a pipe line to the fuel reservoir.

In the arrangement set forth in the preceding paragraph .the liquid stream throttling member (consisting of a needle) emerges directly into the inlet passage so as to utilize the whole of the available energy for the mechanical atomization. Unfortunately, this available energy, although sufiicient at high speeds, is not sufiicient at low speeds and under reduced loads for eflecting directly the desired mechanical atomization.

It is the object of this invention to utilize this energy at hand for creating a forced emulsion with the assistance of a secondary or auxiliary air supply, prior to introducing the atomized mixture into the main air circuit or stream.

On the other .hand, these emulsion-forming systems are well known, both in low-pressure injection systems and in conventional-type carburettors, which comprise in all cases three orifices, that is, a secondary air inlet, a fuel inlet and an outlet for the completed mixture. In carburettors, vnotably, the idling circuit is established under these conditions and it is the vacuum or negative pressure existing in the induction pipe that constitutes the motive power. If this vacuum is strong, the emulsion is complete; unfortunately, the idling circuit of a carburettor cannot have a metering effect or the same etliciency throughout the speed range and load range. In various known fuel injection systems the emulsion obtained in the same manner has no metering effect.

It is the essential feature of this invention to provide an emulsifier based on the same principles as those set forth hereinabove but capable of exerting a metering function, the emulsion chamber consisting of a slide the displacements of which relative to its slide-face is utilized for varying at will the cross-sectional area of the fuel inlet orifice. Although the device is concerned more particularly with an air/fuel mixture, it is applicable 3,003,755 Patented Oct. 10, 1961 2 to any liquid/ gas mixture problems involving an adjustment of the proportions of the component elements.

Many advantages are derived from the possibility of adjusting the proportions of the mixture components at the emulsifier proper. Firstly, a maximum use is made of the energy available Within the liquid under pressure, without reducing this energy by means of upstream throttlings. Secondly, the adjustment modifications resulting from changes in the position of the slide are attended by an immediate variation in the emulsion output. Finally, the liquid output can be cut off completely by leaving thesupply line full, so that in case of sudden re-opening any desired output will be readily available.

It is another specific feature of this invention to provide a mounting of the slide on its slide-face which is particularly simple, elficient and reliable. To this end, the slide is urged against its slide-face by a component constantly proportional to the effort necessitated by its displacement, this feature resulting from the use of blades formed with knife-edges and forming a substantially constant angle in relation to the slide-face. The blade angle may be so selected as to provide the minimum and necessary application force by reducing to the minimum possible value the friction between the slide and its slideface, so that this friction represents but a very reduced percentage of the operating effort.

In order to afford a clearer understanding of this invention and of the manner in which the same may be carried out in practice, reference will now be made to the accompanying drawings forming part of this specification and illustrating diagrammatically by way of example a few typical forms of embodiment of the inven tion. In the drawings:

FIGURE 1 is a diagrammatic axial section showing the slide-valve device of this invention mounted on the induction pipe of an internal combustion engine;

FIGURE 2 is a cross-section taken along the linea-a of FIG. 1;

FIGURE 3 is a longitudinal section of a modified form of embodiment of the slide-valve wherein the emulsiou chamber has a non-conical form of revolution;

FIGURE 4 is a longitudinal section showing a modified embodiment of the slide-valve wherein the emulsion chamber is of oblique frustoconical shape;

FIGURE 5 is a similar section showing another modification wherein the emulsion chamber comprises a first, relatively large convergent cone followed by another, relatively small divergent cone;

FIGURE 6 is a section taken upon the line a a wherein the fuel orifice formed in the slide-face is of triangular configuration, and

FIGURE 7 is a section taken along the line a--a wherein the fuel orifice formed in the slide-face is of rectangular configuration.

The arrangements shown in FIGS. 3 to 5 maybe combined with one another.

Referring firstly to FIG. 1, the reference numeral 1 designates a metal block formed with a fuel feed passage 2 and an air feed passage 3. The fuel feed passage 2, connected to a fuel feed line, leads to an orifice or jet 4 formed in the slide-face 5, the same applying'to the air passage 3. Mounted on this slide-face 5 is a slide-valve 6 comprising an emulsion chamber 7 consisting, in the example illustrated in FIG. 1, of a straight circular frustnm of a cone; however, as shown in FIGS. 3 and 4, this chamber may also have the form of an oblique frustum of a cone or a non-conical form of revolution.

The edge of the circle 8 constituting in the diagrammatic FIGURES 2, 6 and 7 the large base of the frustoconical or like chamber exerts a shutter-like action on the cross-sectional dimension of the fuel jet or orifice 4.

The movements of the slide-valve occurin the direction 3 of the avis bb (FIG. 2) with a useful amplitude at the most equal to the diameter of the jet 4.

The slide travel takes place along the line b-b (FIG. 2) with a useful amplitude at the most equal to the diameter of the fuel jet 4. Under these conditions, the crosssectional area of the air inlet 9 varies but slightly so that the incoming air stream is not retarded irrespective of the position of the slide 6.

The circle 10 designating the small end of the frustum of a cone constitutes the outlet for the emulsion formed in chamber 7. The area of the three orifices, that is, the fuel feed orifice 4, air feed orifice 9 and mixture output orifice 10 are obviously not independent of one another, for the orifice 10 should constantly have a greater passage area than that of the fuel orifice 4, even if the latter is left wide open by the slide, and on the other hand the passage area of orifice 9 should constantly be several times greater than that of the orifice 10 so that the pressure prevailing in the emulsion chamber 7 will differ but slight- 'ly from the pressure obtaining in the air passage 3, whereby a change in the emulsion pressure in chamber 7 will not alter the output of the fuel jet 4 and this output will vary only as a function of the slide position.

The slide 6 has a

groove

11, 12 formed in its upper and lower edges, and a pair of

blades

13, 14 formed with knife-edges engage these grooves respectively so as to form an angle or with the slide-face.

The lower blade 13 is constantly urged by a spring 15 consisting of an elastic blade bearing on the one hand against a pin 16 and on the other hand on an adjustment screw 17. A transverse notch 18 may be formed either in the spring material or in the pin 16, to prevent the spring 15 from moving laterally. The adjustment screw 17 may be locked in the desired position of adjustment by means of a lock nut 19.

The upper blade 14 is urged against the slide 6 by a lever 20 which is not necessarily resilient but is pivotally mounted on a pin 21 and has its uppermost position defined by an adjustment screw 22 also provided with a lock nut 23. 1

The complete assembly described hereinabove, in the specific case of its application to thefeed system of an internal combustion engine, is mounted within a case 24 through which the air sucked by the engine flows under a pressure lower than or equal to the atmospheric pressure according to the degree of aperture of the butterfly air throttle 25 disposed upstream of this assembly.

The fuel jet 4 has been described heretofore as having a circular orifice. A non-circular orifice may be substituted therefor, for example in the form of a triangular or more or less elongated rectangular orifice. as shown in FIGS. 6 and 7.

The fuel feed system emulsifier device described here inabove operates as follows:

By screwing in the adjustment screw 22 the slide 6 is moved downwardly through the medium of the lever 20 and blade 14, and receives simultaneously a reaction from the spring 15 acting through the blade 13. The tension of spring 15 is adjusted beforehand by properly positioning the screw 17 which is subsequently left and locked in this position. The eifort transmitted through the blades =13, 14 is subordinate to the flexion of spring 15.

If F denotes this effort, the component applying the slide 6 against the slide-face will be 2F sin or, and the friction component counteracting the movement of the slide will be 2F sin ocfgga. The materials constituting the slide 6 and its slide-face 5 will be selected to provide the lowest possible coefficient of friction tggo, and the angle a is selected as already explained to have the minimum value. Under these conditions the disturbing effort is practically negligible and the effort necessary for moving the screw 7 22 is substantially equal to the force F of spring 15.

In the case of the application of this device to the fuel feed system of internal combustion engines comprising an induction pipe 24, if p is the absolute pressure prevailing in the pipe, H the atmospheric pressure and P the fuel pressure, the following difierent cases may arise during the operation of the device:

(1) If p=H, that is, if the throttle butterfly 25 is fully open, no air suction caused by the vacuum will occur through the secondary air intake 3 and the whole of the emulsifying energy must be derived from the fuel energy.

rovided that the pressure P be maintained at a sufiiciently high value, the stream of liquid shown at 26 will have a relatively high speed and will impinge against the inner wall 7 of the frustoconical chamber at a relatively small angle 3 to enable it to be reflected almost without any loss of kinetic energy toward and through the orifice 10.

Under these conditions, it is the fuel stream 26 itself that creates an air suction in the passage 3 and, on the outlet side of orifice 10, a first emulsion sufiicient to enable the main air stream 27 leading to the engine to complete a satisfactory atomization.

(2) If p is lower than H, that is, if the butterfly air throttle 25 is partly closed, an air suctionwill take place through the orifice 10 and this energy will combine itself with that of the fuel jet 26 to effect the desired atomization directly on the outlet side of the orifice 10.

It will be noted that the displacement of the slide 6 will alter but very moderately the emulsion conditions, these depending more particularly on the values of P, p and H.

Given a constant value of P, the output will be subordinate to the displacement of the slide 6; this will be a linear function in case the orifice is rectangular as shown at 4 (FIG. 7); this function will be a square one in case the orifice is triangular as shown at 4" (FIG. 6); finally, in the case of a circular orifice 4 (FIG. 2) the output'will vary in accordance with an intermediate law showing an inflexion point when clearing the diameter.

'Of course, the materials selected for the manufacture of the slide 6 and block 1 should have a good resistance to oxidation, whether from the humidity contained in the induced air or from the products likely to be present in the fuels.

I claim:

l. A device for metering and emulsifying gas and liquid substances and delivering the same into a chamber, said device comprising a distributor block having a slide face, a gas passage through said distributor block opening through said slide face, a-liquid passage through said distributor block and opening through said slide face adjacent to said gas passage, means connected to said distributor block for delivering liquid to said liquid passages under pressure, a slide engaging said slide face, said slide having a chamber of generally frustoconical configuration with the large end of said chamber opposing said slide face, said chamber functioning as an emulsifying chamber and the small end thereof forming an emulsion outlet orifice, and support means connected to said slide holding said'slide in engagement with said slide face and positioning said slide relative to said distributor block for controlling the quantity of liquid delivered to said chamber, gas being projected into said chamber at least in part by the kinetic energy of the liquid passing into said chamher.

2. The device of claim 1 wherein said support means are adjustable for varying the overlap of said chamber and said liquid passage to vary the quantity of the delivered liquid. f i

3. The device of claim 1 wherein said support means includes grooves formed in upper and lower edges of said slide parallel to said slide face, blades engaged in said grooves and converging towards said slide face at a slight angle to said slide face, said blades having force components urging said slide against said slide face, a spring member engaging and exerting a predetermined pressure on one of said blades, and an adjustable control lever engaging the other of said blades.

4. The device of claim 1 wherein said liquid passage 76 t? l 13 in 9-1. Dfifice of circular cross section.

5. The device of claim 1 wherein said liquid passage terminates in an orifice of triangular cross section.

6. The device of claim 1 wherein said liquid passage terminates in an orifice of upstanding rectangular cross section.

7. In an internal combustion engine fuel system, a case having a main air passage therethrough including an inlet end and an outlet end, an air flow control valve in said main air passage for controlling the flow of air into said main air passage through said inlet end, a distributor block carried by said case, said distributor block having a slide face, a secondary air passage through said distributor block and having one end opening to the atmosphere and the other end opening through said slide face, a fuel passage through said distributor block and opening through said slide face, means supplying fuel to said fuel passage under pressure, a slide engaging said slide face, said slide having a mixing chamber of generally frusto conical configuration with the large end of said chamber opening to said slide face and the small end of said chamher opening into said main air passage and being subjected to variations in pressures in said main air passage, said chamber overlapping said secondary air passage and said fuel passage for receiving air and fuel therefrom, and means connected to said slide holding said slide in engagement with said slide face and positioning said slide relative to said distributor block for controlling the quantity of fuel delivered to said chamber, the fuel projected into said chamber at least in part drawing secondary air into said chamber and variations in pressures in said main air passage below atmospheric pressure assisting in drawing secondary air into said chamber.

References Cited in the file of this patent UNITED STATES PATENTS 134,372 Frank Dec. 31, 1872 1,275,032 Huene Aug. 2, 1918 FOREIGN PATENTS 21,028 Norway Jan. 16, 1911