US2160067A - Carburetor - Google Patents

Description

May E@ B933 up. XA. Gnsrucca ET AL u INVENToRs mv; www@ aueusrs @mum Y .ummm ucm-immun May ma @ma P. x. A. Gignac@ ET Aa., I PW CARBURETOR Filed June 24, 1936 2 Sheets-Sheet 2 i INVENTORS. PavL KAMER AUGUSTE Glsuccl Y JOHANN MCHTENSTHN RNEY.

Patented May 30,1939 2,160,067

cARURE'roR Paul Xavier Auguste Gistucci, Paris, and Johann Lichtenstein, Levallois-Perret, France, assignors to Societe Generale Des Carburateurs Zenith, Levallois-Perret (Seine), France, a corporation of Switzerland Application June 24, 1936, Serial No. 87,094

f In Belgium August 24, 1935 s claims. (ci. 261-69) The present invention relates to 'carburetors Figures 2, 3, and 4 are similar views showing for internal .combustion motors in which fuel is modifications of the same; and supplied to the fuel discharge nozzles by means Figures 5, 6 and 7 represent the valve of Figure of a reservoir in the wall of which is a diaphragm 4 in various positions.

5 controlling a valve which regulates the supply of The carburetor shown in Figure 1 comprises an 5 fuel to said reservoir'. The reservoir is supplied induction passage I supplied with air through air with fuel under pressure and the diaphragm intake 2 and controlled by throttle valve 3. Inregulates the opening of the valve in such a manduction passage I is supplied with fuel through ner as to maintain in the fuel reservoira definite fuel nozzle 4 opening posterior to throttle valve pressure. Such carburetors are already known 3 and controlled by a needle 5 actuated rnechani- 10 particularly as shown in applicants Belgian patcally by throttle valve 3 through lever 6, link 1 ents, No. 369,960 `of May 1, 1930; No, 369,961 of and lever 6pivoting at 9. May 1, 1930; No. 404,966 of August 30, 1934; and The f uel nozzle 4 is supplied by fuel reservoir No. 406,646 of December 5, 1934. I0 which in turn is supplied with fuel under pres- According to the present invention a depressure through a passage Il. The fuel reservoir I0 sion chamber is connected to the carburetor incomprises a diaphragm I2 connected to a valve duction passage by a depression passage. This I3y regulating the supply of fuel to the reservoir.

depression chamber comprises a movable parti- Diaphragm i2 iS alSO Connected by a rOd i4 t0 tion, which may be either a diaphragm or a pisone,of the arms I5 of lever I5, I6 pivcted at I1. ton and this movablepartition is connected to A depression chamber 20 communicates with 20 the fuel reservoir diaphragm by a mechanical the induction passage I through a passage 2| connection arranged in sucha way that the force which Opens therein at 22, preferably in the exerted by the depression on said movable parvicinity of fuel nozzle 4 in such manner that the tition and transmitted to said diaphragm through depression transmitted to chamber 20 is approxiopening of the valve. The force thus transmitted Passage 2l is controlled by a valve 33 which may to the fuel reservoir diaphragm increases the be manually actuated by means of a lever 34. A value of the pressure maintained in the fuel resdiaphragm 23 is placed in the Wall 0f the depreservoir by said diaphragm. sion chamber 20 and is connected by a rod 24 to The design forming the subject matter of the the second arm I6 of lever I5, I6. The force 30 present invention is for the purpose of increasing exerted by the depression `0h diaphragm 23 iS Athe supply pressure 0f they fuel discharge and transmitted by the rod 24, lever l5, i6, and rod I4 consequently to increase the drop in pressure at to diaphragm l2 and t0 Valve I3 ahdthiS OI'Ce the orifices discharging the fuel into the mixing tends -to open valve I3.

chamber of the carburetor. Diaphragms I2 and 23 separate respectively fuel 35 As is well known, at higher altitudes the relareservoir I0 and depression chamber 20 from a tive depression in the induction passage. decompartment 25 which communicates with the creases, so that the pressure drop at the fuel noz- CarburetOr intake 2 thIOllgh a PaSSage 26. C0111- zle becomes too small to permit accurate meter- Dartment 25 might, however, be omitted and di- 4-0 -ing or efcient atomization of the fuel. This is aphragms I2 and 23 then be exposed directly t0 40 remedied in the present invention by increasing, the atmosphere'. with increasing altitude, the pressure* under which An altitude correctoris provided in the form of the fuel is supplied to the nozzle. This is aca passage 26 which leads from compartment 25 to complished by bleeding air from atmosphere, or the air intake 2, and is provided with a calibrated' 4.5 from the air entrance of the carburetor, into the orifice 2l; also a` rasage 28 which leads from 45 depression chamber, and controlling, either compartment 25 to the induction passage at 22 manually or automatically, the amount of such and is controlled by a valve 29 which is manually bleeding so as to make it proportional to the operated by mea-ns 0f an arm 30, t0 Vary the relabarometric pressure. tive effective cross-sections of passages 26 and Other objects and advantages of the invention 28 and thus control the depression transmitted to 50 will be apparent from the following description, compartment 25- Chamber 20 also communitaken in connection with the appended drawings, cates with air intake 2 through passage 3I having in which: a calibrated orifice 32'. I

Figure l is a diagrammatic representation of a The operation of the mechanism is as follows: v

carburetor embodying the invention; The upper face of diaphragm I2 is subjected to 55 this mechanical connection tends to increase the mately' the, Samey aS that acting on fuel nozzle 4. 25-

the pressure existing in compartment 25 and the lower face is subjected to the fuel pressure in balanced value such that the difference between that pressure and the pressure, acting upon diaphragm I2, balances the force exerted bythe depression acting on diaphragm 23. If the pressure in reservoir I falls below this balanced value, the forces applied to the upper face of diaphragm I2 become preponderant and diaphragm I2 is lowered and further opens valve I3. The fuel pressure in reservoir I0 rises again and balanced pressure is re-established. Conversely, if the pressure in reservoir I0 rises above the balanced value, diaphragm I2 will be raised and will tend to close valve I3 which will cause a decrease of pressure in reservoir I0 and bring about a balanced condition.

The pressure drop under which the fuel discharges from nozzle 4 is equal to the difference between the pressure in fuel reservoir I0 and the pressure in intake passage I. The depression transmitted to the depression chamber 20 causes an increase of pressure in fuel reservoir I0 and consequently increases the pressure drop under which the fuel discharges from nozzle 4. For example, if diaphragms I2 and 23 have equal working surfaces and the arms of lever I5, I6 are equal, the difference between the pressure in fuel reservoir I0 and the pressure in compartment 25 should be equal to the difference between the pressures existing in compartment 25 and in the depression chamber 20, that is it should be equal to the depression which it should balance. The drop in pressure under which the fuel discharges from nozzle 4 is then equal to twice the depression, that is it is twice as great as it would be in a diaphragm type pressure regulator of the known type in which depression chamber 20 and diaphragm 23 are not present.

At an altitude where the density ofthe air is half of the density of the air on the ground, the fuel in a carburetor of the type shown in Figure l discharges under a drop of pressure which is the same as in a carburetor of the usual type operating on the ground and which is not provided with the mechanism of the present invention.

In order that the pressure in fuel reservoir I0 may effectively be regulated by the mechanism constituting the present invention, it is evidently necessary that the fuel be supplied to reservoir I0 through passage II under a higher pressure than the regulating pressure in reservoir I0. During idling operation on the ground, the depression in the intake passage is around 500 grams per square centimeter. The regulating pressure in reservoir I0 for this value of depression is then also 500 grams per square centimeter. In order that the mechanism mayeffectively regulate the pressure in the fuel reservoir itself for this maximum value of depression, it will be necessary that passage II supply the fuel to reservoir I0 under a pressure higher than 500 grams per square centimeter.

The values in the above example have been chosen merely lfor simplicity of explanation; in general, the pressure in the fuel reservoir would not be increased in such proportions. Preferably the surface area of diaphragm 23 would not be decreased relative to the surface area of alsace? diaphragm I2 in order that diaphragm 23 may have the degree of movement required for the operation of the device. Preferably diaphragm 23 should have the same working surface area as diaphragm I2, but the lever arm I6 should be shorter than lever arm I in order to diminish the eort transmitted from diaphragm 23 to diaphragm I2. As a practical example, the lever arm I5 may be twice as long as lever arm IB. The pressure increase in the fuelreservoir will then be equal to half of the depression, and the pressure drop under which the fuel discharges from nozzle 4 will thus be increased 50%, which as a rule will be suflicient to supply an accurate fuel proportion and give atomization of the sameA at all altitudes practically attainable. For the maximum depression', which is approximately 500 grams per square centimeter, the corresponding pressure in reservoir I0 would be 250 grams per square centimeter, which will be sufficient if passage II supplies fuel under a pressure higher than 250 grams per square centimeter in order that the pressure regulator may function effectively under all operating conditions.

It is evident that the section of fuel discharge nozzle 4 is smaller in the arrangement shown in Figure 1 than in a carburetor not comprising the mechanism of the present invention.

The depression transmitted to compartment 25 causes the diminution of regulating pressure in fuel reservoir i0 and consequently decreases the discharge of fuel. This diminution becomes greater as the depression transmitted to compartment 25 increases. The operation of lever 30 thus permits the proportion of the mixture delivered by the carburetor to be varied as the altitude varies. Obviously, lever 30 may be operated automatically, or instance by means of an aneroid capsule.

By regulating the depression transmitted to depression chamber 20 it is possible to regulate the force transmitted to diaphragm 23 and diaphragm I2 and consequently to modify the quantity of fuel supplied by a fuel nozzle 4, that is it is possible to modify the richness of the mix-v ture supplied by the carburetor.

Lever 34 allows the modification of the section of .depression passage 2I relative to the section of calibrated orifice 32 and permits consequently the modification of the depression transmitted to depression chamber 20. Valve 33 may obviously be replaced by a valve located in passage 3| or else by regulating means modifying simultaneously the sections of passages 2| and 3|.

When valves 29 and 33 are closed, the pressure on the two faces of diaphragm 23 is the same and the mechanism functions as if diphragm 23 and chamber 20 were omitted. 'I'hen if membranes I2 and 23 are of equal' area and lever arms I5 and I6 of equal length, as shown, valve 33 may be opened to such extent as to transmit to the depression diaphragm 20 a depression equal to 20% of the depression existing in intake passage I at the end 22 of depression passage 2I, whereupon the quantity of fuel supplied by fuel' nozzle 4 will be increased approximately 10% and the mixture is enriched accordingly. In order to obtain the same enrichment in a device wherein arm I5 is twice as long as arm I6, it would be necessary to transmit to depression chamber 20 a depression equal to 40% of the depression existing at 22 in the intake passage I. In an important application of the present invention a carburetor would be regulated in such 2,1eo,oo7 I vbility of the motor. In order to decrease the a manner as to supply a lean mixture for economical operation when valve 33 is closed and a rich mixture permitting the motor to develop its maximum power when valve 33 is open. A suitable calibration may be provided in valve 33 or in passage 2l in order that a full opening of valve 33 may correspond to the correct rich mixture a1- lowing the motor to develop its full power.

In the arrangement shown in Figure 1, the enrichment obtained for a given'l position of valve 33 is not constant, since it depends'on the depression transmitted to compartment 25, that is it depends on the position of valve 29. 'I'his shortcoming is overcome in the carburetor shown in Figure 2. l'n this carburetor the air conduit 3l of the carburetor shown in Figure l is replaced by a passage 35 connecting the depression chamber 28 to compartment 25. A calibrated orifice 35' is placed in passage 35. Preferably the section of orifice 35 should be small relative to the section of orice 2li in order that escape of air which is taking place through orifice 36 when valve 33 is open does not modify proportionately the depression which is transmitted to compartment 85 and which is regulated by means of valve 2S.

The carburetor shown in Figure 3 represents a variation of the carburetor shown in Figure 2 in which the depression transmitted to compartment 25 is regulated automatically as a function of the depression existing in the intake passage l as was described in applicants Belgian Patent No. 406,646.

In Figure 3 a chamber 3l communicates freely through passage il with depression port 22 which opens into the induction passage l. The pressure existing in chamber 3l is then the same as the pressure existing at 22. Depressionpassage 2l controlled by valve 33 opens into chamber 3? the same as passage 28 of Figures l and 2 which transmits the depression to compartment 25.

Valve 28 in Figure 2 which controls the section of passage 28 is replaced in Figure 3 by a profiled rod 48 controlling a calibrated orifice 39 and attached to an expansible capsule 38 located in chamber l. Capsule 38 expands or contracts as a function of the pressure existing in induction passage I in such a manner `that the section of the` orifice passage 39 and the relation between this passage section and orifice 2l is regulated by rod 48 as a function of the pressure in induction passage i. By suitably profiling rod 40, a full automatic carburetor is obtained both .in its operation on the ground and at altitude, that is the proportion of the mixture supplied by the carburetor remains correct irrespective of throttle opening, motor speed, or altitude. Under these conditions the carburetor may be regulated (by suitably proling needle 5) in such a manner as to supply a lean mixture for economical operation when valve 33 is closed and to supply a richer mixture for normal operation or to allow the motor to develop its vfull power when valve 33 fuel consumption, it is possible to lower the mixture richness below the so-called normal mixture richness, which already is a relatively lean mixture, but this mixture cannot b e used at large throttle openings without danger to the valves and it is equally preferable not to use it at slight openings of the throttle valve.

Figure 4 shows a variation of the carburetor shown in Figure 3 in which a leaning arrangement controlled by the pilot permits switching A second from normal mixture to lean mixture. arrangement controlled by the throttle valve renders the leaning arrangement inoperative at large openings of the throttle valve, that is even if the pilot leaves the leaning arrangement in the lean position, when the throttle valve is brought into wide open position or into the idling position this second arrangement intervenes to re-establish normal mixture. This second arrangement furthermore may enrich the mixture at wide open throttle positions and in idling positions of the throttle valve. I

, In the arrangement shown in Figure 4 depression passage 2! comprises a valve 42 Which can be operated by the pilot by means of lever 43. The leaned position of the leaning arrangement corresponds to the closed position of 'valve 42, while the open position of this valve as shown yin the drawings corresponds to the normal position of the leaning arrangement. Section 45 of passage 2| between the valve d2 and depression ,chamber 20 is provided with a calibrated orifice 44. Passage '45 communicates through passage d6 withbody 4l of valve 48. yValve 48 is operated by lever 4S connected by link 53 to lever 5i xed to the axis of throttle valve 3. The valve body 4l communicates also with chamber 37 through passage 52 and with depression chamber 28 through passage 53 which is provided with a calibrated orifice 54.y Valve 48 has four parts 55, 56, 5l and 5B. y

In Figure 5 valve 48 is shown in a position corresponding to Wide open position oik throttle valve 3.

In Figure 6 it is shown in a position corresponding to an intermediate position of the throttle valve, while in Figure 7 it is shown in`a position corresponding to the closed position of the throttle valve.

If both of valves 42 and 48 are closed, depression chamber 20 then communicates only with compartment 25 through orice 36 with the result that the pressure on both sides of diaphragm 23 is the same and diaphragm 23 does not transmit any force to diaphragm I2. The mixture supplied by the carburetor under these conditions is a so-called lean mixture.

If passage 45 communicates with chamber 31, passage 53 still being shut off by valve 48, the depression chamber 28 communicates then with the intake passage I through calibrated orifice 44. A certain depression is then transmitted to chamber 28 and diaphragm 23. 'Ihe mixture is then richer than in the preceding case and constitutes so-called normal mixture. f

If both passages 45 and 53 communicate with the chamber 31, depression chamber 20 communicates with intake passage l through both calibrated orices 44 and 54. The depression transmitted to the depression chamber 20 isstill greater and the mixture is still richer. The mixture supplied by the carburetor under these con'- ditions is a so-called rich mixture.

When lever 43 is placed in normal position,

valve 42 is opened and depression chamber 20 communicatesV with chamber 31 through passage 45 no matter what the opening of the throttle valve.

At medium openings of the throttle valve (F'gure 6) the passage 53 is closed by valve 48 and the mixture delivered is normal.

At wide open position of the throttle valve (Figure 5) passage 53 communicates with passage 52 and chamber 31 through channels 58 and 56 of valve 48. The mixture supplied is rich.

When the throttle valve is in the vicinity of its closed position (Figure 7) passage 53 still communicates with passage 52 and chamber 31 through channels 51 and 55 of valve 48. The mixture supplied is still rich. y

When' lever 43 occupies the lean position, valve 42 is closed and the operation of the arrangement is as follows.

At medium openings of the throttle valve (Figure 6) `the three passages 52, 46 and 53 are shut oil by valve 48. As valve 42 is also closed, depression chamber 20 has no communication with the induction passage I and the mixture supplied is lean. At full opening of the throttle valve (Figure 5) passage 45 communicates with passage 52 and chamber 31 through passage 46 and channels 55 and 56, While passage 53 communicates with passage 52 andk chamber 31 through channels 58 and 56. The mixture supplied is rich even though lever 43 is in lean position.

When the throttle valve is in the vicinity of its closed position (Figure 7) passage 45 communicates with passage 52 and chamber 31 through passage 46 and channels 58 and 55 while passage 53 communicates with passage 52 and chamber 31 through channels 51 and 55. The supplied mixture is rich even though lever 43 is in lean position.

It can be seen from the drawing that the different channels in valve 48 are larger than the outlets of the ydifferent passages opening into Valve body 41. Because of that, passages 48 and 53 begin to communicate with passage 52 when the throttle valve is not yet completely closed. A rich mixture is thereby obtained at slight openings of the throttle valve before the same is completely closed, the angle of the opening below which the rich mixture is attained being governed by the size and location of these channels.

The location of the channels is such that when the throttle valve is closed from wide open position (Figure 5), passage 53 is shut off immediately while passages 46 and 52 remain in communication until the throttle valve is closed to a certain angle. lThe calibrated orifice 54 is then shut off from communication with chamber 31 while orince 44 continues to communicate with that chamber through passages 45, 46 and 52. The mixture is then normal even though lever 43 occupies the lean position. The location and size of the channels of valve 48 permit the determination of the opening angle above which the leaning arrangement is rendered inoperative.

It is evident that if one wishes to accomplish by means of valve 48 only part of the functions which it serves in the arrangement shown in Figure 4, those valve channels or passages opening into its Valve body may be omitted which correspond to the functions that it is not desired to accomplish.

If it is desired not to produce by means of valve 48 an enrichment at closed or slightly opened positions of the throttle valve, channel 51 of valve 48 may be omitted. The enrichment at slight openings may then be obtained by a suitable profiling of needle 5 which regulates the fuel discharge at nozzle 4; likewise the enrichment at wide throttle openings obtained by the operation of valve 48 may be eliminated by omitting passage 53, and this enrichment can be obtained by a suitableprofiling of needle 5.

If finally it is desired not to render inoperative the leaning arrangement at slight openings of the throttle valve, it will sufiice to re-locate channel 58 of valve 48 and corresponding channel 51 in the outlet of channel 53 in the valve body 41 in such a manner that channel 58 does not register with passage 46 at slight openings of the throttle valve.

We claim:

l. Inra charge forming device for an internal combustion engine, an induction passage, a throttle controlling the same, a fuel nozzle discharging in said induction passage posterior to the throttle valve, a fuel chamber connected to said nozzle and having a movable wall, a valve controlling the inflow of fuel to said chamber and connected to said movable Wall, a depression chamber having a movable wall connected to the rst mentioned movable wall, a depression conduit connecting the depression chamber to the induction passage posterior to the throttle, a second conduit connecting the depression chamber to the induction passage anterior to the throttle, and means operated in accordance with throttle position for varying the cross section of one of said conduits.

2. The combination dened in claim 1, comprising in addition a compartment interposed between the fuel chamber and the depression chamber and having in common therewith the movable walls thereof, said compartment communicating with the induction passage anterior to the throttle.

3. 'Ihe combination defined in .claim 1, comprising in addition a compartment interposed between the fuel chamber and the depression chamber and having in common therewith the movable walls thereof, and a restricted connection between the depression chamber and the compartment.

. in said induction passage, a fuel chamber connected to said nozzle and having a movable wall, a valve controlling the inow o'f fuel to said chamber and connected to said m'ovable wall, a depression chamber connected by a depression passage to said induction passage posterior to the throttle and having a movable wall also connected to said valve, a conduitconnecting the depression chamber to the induction passage anterior to the throttle, means including saidv movable walls forming a chamber communicating with said conduit, and pressure responsive means for varying the relative effective cross sections of the depression passagevand the conduit.

5. The invention dened in'claim 4, wherein the pressure responsive means comprises a valve the operation of which is controlled as a function of the pressure obtaining in the induction passage posterior to the throttle.

6. The invention defined in claim 4, comprising in addition a manually, operated valve controllingthe depression passage.

7. Ina charge forming device for an internal combustion engine, an induction passage, a throttle controlling the same, a fuel nozzle discharging in said induction passage, a" fuel chamber connected to said nozzle and having a movable wall, a valve controlling the inflow of ful to said chamber and connected. to said movable wall, a depression chamber connected by a depression passage to said induction passage posterior to the throttle and having a movable wall also connected to said valve, a conduit connecting the depression chamber to the induction passage anterior to the throttle,.pressure responsive means for varying the relative effective cross sections of the depression passage and the conduit, and means actuated by throttle movements for controlling the conduit.,

8. In a charge forming device for an internal combustion engine, an induction passage, a throttle controlling the same, a fuel passage discharging in said induction passage, a fuel chamber.

connected to said fuel passage and having' a movable wall responsive to pressures in the chamber, a valve controlling the inflow of fuel to the chamber and connected to said movable wall, a depressionv chamber connected by a depression conduit to said induction passage and having a movable wall also connected to said valve, a conduit connecting the depression chamber to the' induction passage anterior to the throttie, means jointly responsive to throttle position and barometric pressure for varying the relative eifective cross sections of said conduits, and means controlled in accordance with throttle position for varying the effective cross section of said fuel passage.

c 9. In a charge forming device for an internal combustion engine. an induction passage, a throttle controlling the same, a fuel nozzle discharging in said induction passage, a fuel chamber connected to said nozzle and having a movable wall responsive to pressures in the chamber, a valve controlling the ini-low of fuel to the chamber and connected to said movable wall, a depressionchamber connected by a depression passage to said induction passage and having a movable wall also connected to said valve, a conduit connecting the depression chamber to the induction passage anterior to the throttle, pressure responsive means for varying the relative effective cross sections of said conduits, a compartment comprising said movable walls, a calibrated orifice between said compartment and said depression chamber, and a connection between the compartment and the induction passage.

PAUL xavma AUGUSTE Grs'rUccI. JOHANN ucn'rmrs'xm.

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