US2197555A - Carburetor - Google Patents

Description

Am w. ww E. M. J. LEPICARD 2,197,555

/ Arr/s Patented Apr. 16, 1940 UNITED STATES CARBURETOR Etienne Marie Jules Lepicard, lNeuilly-sun?Seine, France Application January 6, 1937, Serial No. 119,352-

In France January 9, 1936` 1 claim. (cl. :rs1-t9) This invention relates to a method and a device for the formation of a carbureted mixture.

A rst object of the invention is to provide improvements in and relating to carburetors for e thermal engines, so as to obtain a carbureted mixture Without appreciable charge losses in the suction branch pipe and, therefore, a great power at high speeds while insuring the supply of fuel even at very small speeds.

lo Another object of the invention is to provide carburetors which are easy to disassemble and to regulate.

Still another object of the invention is to provide a carburetor in which no re can be pro- 15 :duced even through a violent back firing.

Still another object of the invention is to ob-v tain the full power of the engine at a predetermined moment through an enrichment of the carbureted mixture in combination with an in- 20 crease of the useful section for the suction of the said carbureted mixture.

'I'he invention relates rst to a method for the formation of a carbureted mixture for thermal engines, which consists in providing for the for- 25 mation of vortex trains in the air current which is sucked and in feeding the fuel into the high vacuum axial zone of the air eddies which are thus formed, while thus insuring the energetic suction of the fuel with a minimum of charge losses, whatever the speed of the engine may be.

The method according to the invention can be carried into practice in a very large number of different manners without departing from the scope of the invention. 35 On the other hand, carburetors according to the invention possess the features which will be apparent from the following description and from the appended claim.

Carburetors according to the invention are shown by Way of examples in the accompanying drawings, in which:

Figure 1 is a top plan view of a carburetor unit according to the invention, the cover being removed.

Figure 2 is an axial sectional view through the line 2 2 in Figure 1.

Figure 3 is a sectional view on the line 3 3 of Figure 1.

Figure 4 is a cross sectional view according to the line 4-4 of Figure 3.

Figure 5 is a partial perspective view showing y the sloping vancs which produce the formation or the air eddes. M Figures 6 and. 7 are partial sectional views.

through the lines 6--6 and 1-1 respectively in Figure 1.V Y y Figure 8 is a partial perspective view showing the control lever Ifor the needle valve.

Figure 9 is a similar sectional view as Figure 2, 5 but showing another position of the butterfly valve.

Figures lO'and 11 are anaxial sectional view and a perspective view respectively of another carburetor unit according to the invention. 10

The carburetor shown inFigures 1 to 8 is a so-` called down draftcarburetor, that is to say a carburetor inwhich the carbureted mixture ows downwardly.

This carburetor comprises a chamber (Figures 1 to 4) which through the medium of bosses 81 krests on the flange 2 which forms the suction -pipe and comprises a control buttery valve IIJ,

According to the invention ribs forming a centripetal guiding device for the air are provided in the space Il between the chamber 1 and the pipe 2. The said ribs, which are advantageously formed of the bosses 81 integral with the chamber 'i (Figures 4 and 5) are inclined with re- 25 spect to the radii of the circumference l2 which forms the apparent outline of the chamber l. One of the faces |31 of said ribs 81 is nearly tangent to the circle I4 which forms the straight part of the pipe 2. The axis of this set of ribs coincides with the axisof the chamber l.

The bottom l5 of the chamber 'I' still comprises a boss I6 (Figures 4 and 5) which forms a deflector and is limited by a revolution surface the axis of which coincides with the axis of the chamber l. Through this boss extends the jet spray nozzle l (Figures 2 and 3) through which the chamber 'l communicates with the pipe 8'.

The chamber l' still receives a pipe Il for the supply of petrol Aand a drain pipe `I8 (Figures 1 0 and 3).

The space ll in which the ribs 81 lie is connected with an annular space I9 (Figures 2, 3 and 4) between the chamber l and an outer casing 20 communicating with the atmosphere; thus, these various elements form air suction means through their combination.

The chamber 'l` is provided with a cover 2|, While the outer casing 20 is provided with a sec- 50 ond cover 22; both these covers are in a staggered relation with another so as to provide between them a space 23; moreover, the cover 22 covers the whole unit.

Theinner part of the chamber 'I receives the 55 main nozzle I mentioned above, the starting nozzle 24 or starter and the idling nozzle 25.

'Ihe main nozzle or power nozzle comprises a power emulsioniser on the top of the boss I6; on this emulsioniser, which comprises an extension formed by the pipe I, is a space 26 comprising an upper channel 211, 212 through which the pipe I communicates with the space 23 between both covers 2| and 22. This channel 211, 212 opens opposite the pipe I through a nozzle' 28 the section of which is narrowed 'and slightly smalle v than the section of the tube I.

The space 26 extends in its upper part through the covers 2| and 22; it is threaded as shown by the reference number 29 so as to receive a bushing 3D which, on the other hand, is threaded' onto the tube I itself in itslower part.

Through openings 3I-32 in the branch pip 21 and in the bushing 38 respectively the power nozzle I-26 communicates with the inner part of the chamberA 1.

Lastly a nut 33 threaded onto the pipe 21 serves at secure the cover 2| which covers the whole unit; thus, the said cover is easily removable, since it is sufficient to unscrew the nut 33 for removing the cover.

The starting nozzle or starter comprises -an emulsier 24 threaded into the bottom of the chamber 1; this emulsier 24 extends through .gjthis bottom aswell as through one of the bosses 81. and is then connected with a channel 34 in the wall of thesuction pipe' 2, said channel communicating with the pipe below fthe throttle valve I0 when this latter is closed.

The emulsioner 24 is covered by the nozzle proper 35 which communicates in its lower part with the chamber 1 and in its upper part withA the space 23 between both covers 2I-22, as shown at 351.

The nozzle 35, which comprises the calibrated opening forgthe passage of the fuel, extends through both covers 2I-,22 and thus allows for the free passage of the control rod 36 for the flap valve 31which normally closes the emulsi- The idling nozzle, the section of which is smaller than the section of the two other nozzles, also comprises an emulsier 25 which extends through one of the bosses 85 of the chamber 1 and is connected with a channel 38 opening at 39 into the pipe 2 on the lower side of the throttle Valve I0`.

This emulsier 25`is also covered by a bushing 40 which forms the idling nozzle proper and comprises an upper opening 401 through which the said nozzle communicates, on the onehand, with the .inner part of the chamber 1 and, on the other hand, with the space 23 between both covers 2I-22. '1

Thus, the chamber 1 and the three nozzles 8,

`25, 24 appertaining to the same form a unit which is removably mounted on the branch pipe. The chamber 1 also comprises a constant level device which controls the fuel supply and is A :formed of a oat 4I actuating a needle valve 42.

AAccording'to an interesting feature of the invention the main nozzle I, the idling nozzle 25 and the starting nozzle or starter have thus been grouped together in one and the same fuel chamber 1.

,-5 lThis arrangement makes the unit easier ...to

manufacture and permits, on the other hand, to adjust the said unit on pipes sloping in a different manner. In the case of the above described embodiment of the invention, the pipe I is vertically arranged, but other carburetor types will be described hereinafter. l On the other hand, the nut 33 through which the cover 22 is secured is provided with a flange 331 acting as a screw-driver. This makes the disassembly of all the nozzles and drain plugs possible; therefore, the whole carburetor unit can be disassembled Without any tool.

According to another interesting feature of the invention the casing 20 is formed of a sieve or perforated sheet'so as to form an air filter which completely encloses the chamber 1.

Thus, the carburetor is completely enclosed by the filter 28 so that not only the main air inlet formed of the space II, but also the emulsion air inlet 21a, the air inlet 401 for the idling nozzle and'theair inlet 351 for the starter 24 are thus protected.

The needle valve 42, which is actuated by the oat 4I, is inserted between the fuel supply pipe I1 and the chamber 1. For this purpose the said needle valve controls an opening 43 which communicates with radial ports 44 opening into a compartment 45 of the chamber 1.- A partition 46 separates the chamber. 1 from the compariment 45 which, on the other hand, is covered by a sieve 41.

The unit formed of the compartment 45 and the sieve 41 forms a decantation lter.

The decantation filter being included in the chamber 1, this arrangement also contributes to reduce the space required by the unit, the fuel flowing through this iilter before entering the chamber. I

The float 4I controls the needle valve 42 by means of a lever 48 comprising a fork 481 (Figures 1, 3 and 6 to 8) swingingabout an axis 49 carried by two screws 50, 5I to this end said axis comprises two loops 52, 53 resting on the screws 50,'5I respectively; springs 54, 55 which are held by screws 56, 51 press against the loops 52, 53

- entails a change in the level of the fuel in the chamber 1, since for one and the same position of the needle valve 42 the height of the ltloat 4I and consequently the fuel level are modied.

Since the cover 22 of the chamber 1 is removably mounted and since the nozzles I, 24, 25 are xedly secured to the bottom of the chamber 1 separately from another, it is thus possible, after having removedy the said cover, to have access to the nozzles I, 24,- 25 in order to verify their operation as well as to inspect the operation of the device 4I, 42 with the constant level and lastly to verify the fuel level'. All these operations can be effected while the engine is running.

On the other hand, owing to the possibility of adjusting the axis 49 of the oat 42 in combination with the fact that thecover 22 of the chamber is removably mounted, it is also possible to control the fuel level while the engine is running.

The unit comprising the oat 4 I itsaxis 49 and thefneedle-valvef42.controlled by the said float can thus be removed by hand -without disturbing the fuel level.

The operation of the carburetor is as follows: When normally running the engine sucksy in the direction f3, which produces a vacuum determining the entrance of air in the direction f4 on the whole periphery of the outer air filter.

26; the said air enters the space I9 which acts as collecting chamber, then it flows into the space II where it meets with the vanes 81, E2 The said vanes 81, ii2 are thus acted upon in the direction f3 on their periphery, so that said vanes impart a rotating movement to the air vein entering the suction pipe 2.

According to the method which forms the object of the invention the fuel is supplied just at the point 6 where the whirling movement of the air begins; this fuel supply is'made from the chamber I by means of the nozzle I which opens at 6 just at the point where the whirling motion begins. l

Thus the fuel enters the nozzle 2 in a zone 6 where the eddy current 5 has its maximum speed. On the other hand this inlet point 6 lies in the axis Z Z of the eddy current, that 'is vto say in the zone where the vacuum caused by the whirling movement of the air reaches its maximum, since the air rotating in a whole has, under the iniluence of the centrifugal force, a tendency to be rareed in the centre, while being compressed about the periphery.

Moreover, the air which flows through the filter 20 and into the space 23 between the covers 2 I-22 enters in the direction f6 into the chamber 26 of the main nozzle and causes the emulsication of the fuel entering in the direction f".

The emulsion which has been thus formed is carried away in the direction f8 into the tube I under the action of the vacuum produced in the emulsier 6 by the whirling movement of the air.

The quantity of carbureted mixture admitted into the engine is controlled by means of the throttle valve I6.

Brieiiy stated, the vacuum which is produced at the point 6 where the air is admitted keeps always a value which is compatible with a good suction of the fuel, as well when the engine runs at a small speed as when it runs with its full power.

Since the method according to the invention avoids the adjunction of any device such as a diffuser by which the flow of air is throttled, the efciency of the engine has always a high value at all speeds.

The nozzle 25 is used only when the engine runs idle, that is to say when the throttle valve I6 is closed (Figure 2).

As to the starting nozzle or starter 24, it is actuated, for starting purposes, by means of the rod 36.

The rotating valve IIJ advantageously comprises a helicoidal surface the axis T T' of which is perpendicularto the axis of rotation |01 of the throttle valve IIJ (Figures 2 and 9); thus this valve acts as a guiding device for keeping the eddies in motion.

When the throttle valve Ill is open, the axis T T coincides withthe axis of the pipe 2.

On the other hand, the pitch of the helicoidal surface I6 has the same direction as the whirling movement of the current of air which has been carbureted, so that when the throttle valve I0 is open, the helicoidal surface which forms the same keeps and maintains the whirling movement.

' Thus it is provided a device which can be used in a very general manner. for various applications and which permits to cause the formation of a whirling movement in any vein of Huid.

In this device the throttle valve itself serves as a guide for the fluid veins and through this arrangement it is possible to reduce to a minimum the number of parts inserted in the fluid vein and, consequently, also to reduce to a minimum the charge losses in this fluid vein.

.The helicoidal surface which forms the throttle Valve Ill is limited, on its periphery, so that the outlinefof the throttle Valve I0, when in the closed position, exactly adapts itself to the form of the inner walls of the pipe 2 and thus insures a fluid tight engagement.

Inv the carburetor shown in Figures 10 and ll the starter 24 is normally closed by the ap valve 3l which is urged by the spring 50.

The starter is actuated by means of the accelerator pedall when said vpedal is totally depressed.

To this end, the flap valve 31 of the starter 24 is connected, through vits rod 36, with a lever 52 pivotally mounted on an axis 53 carried by the chamber I or by the cover of this chamber; said lever 52 ispivotally connected to the end of a rod 54 the other end of which freely extends through a barrel 55 swinging at the end of the lever 56 of the throttle valve I 0.

The rod 54 carries at its end a stop 5l engaging the barrel 55 of the leverv 55 when the throttle valve Ill is brought to a poistion near the full opening, that is to say when the accelerator pedal 5I is totally depressed (position C of the lever 56). For all the other positions of the pedal 5I the boss 55 of the lever 56 freely slides on the rod 54, so that the flap valve 37,01 the starter 24 remains in its closed position. Thus a one-way connection between the pedal and the starter 24 is obtained. l

Therefore, the starter 24 can be actuated by means of the accelerator pedal 5I only when the latter is about to reach its end position when totally depressed.

Then an appreciable enrichment of the whole carbureted mixture admitted to the engine as well as an increase of the useful intake section for this while carbureted mixture are obtained. In fact, the section of the rich carbureted mixture Vein admitted through the starter 24 and entering beyond any hindrance `or throttling of the carburetor pipe is added to the smaller section of the main carbureted mixture vein, that is to say, in the example shown, the free section between the walls of the pipe 2 and the throttle valve I0.

It is therefore possible, through this arrangement, automatically to obtain the full power of the engine without the adjunction of any other complementary part and this with an opening 32 of the main nozzle which is smaller than in the case in which said opening were to insure alone the full power, which permits to maintain an economical regulation for all the intermediary speeds; in fact, this main nozzle the opening of which is smaller than in the case in which it were to insure alone the full power gives a mixture which is poorer and consequently more economical when running at mean speeds, the throttle valve being not fully opened.

The starter 24 is actuated in the ordinary manner, for instance by means of a pull rod 53 located on the dash-board of the car, as in the known arrangements; the pull rod 58 acts on a flexible transmission cable 59 having a sheath 60. "The end fthe cable 59 receives' a stop 6I engaging a boss 62 of the chamber 1, the cable 59 extending through said bossage 62. The sheath 60 of the cable 59 is rigidly connected with a small plate 63 secured to the rod 54 of the starter 24.

l Any pull exerted by the rod 58 on the cable'59 determines a reaction through which the small plate 63 is brought nearer to the stop 6I, the latter being maintained in a xed position by the boss 62; this results in a lowering of the rod 54 and, consequently, an opening of the flap valve 31 of the starter 24, which operation, however, has no iniluence on the opening 24 of the throttle valve Ill.

Thus, both actuating means for the starter 24 act only in Oneway and independently of another without counteracting 4each other.

In this carburetor' it is desirable according to modification of the device as illustrated in Fig. 10 to provide a single gasoline intake opening 32 for the main nozzle I and the idling nozzle 25;

To this purpose, both nozzles I-25 are connected with another by a duct 64 in the bottom of the chamber, this duct insuring the communication between both nozzles I and 25. Both nozzles I and 25 are then supplied with gasoline only through the opening 32 which supplies the main nozzle I.

When the engine is idling, the throttle valve I is closed and the vacuum acts at 39 on the idling nozzle `25 which is supplied with gasoline by means of the bottom of the main nozzle I.

When the engine normally runs, the vacuum is greater at 6 than at 39 because of the whirling movement which is imparted to the drawn in air; the opening 32 then discharges only into the main nozzle I. Thus every useless output of the nozzles I, 25 independently of each other is avoided.

I claim:

In a down-draft carburetor, an annular fuel chamber, a mixture outlet pipe extending downwardly from a point beneath said chamber, a primary mixture conduit arranged coaxially through the chamber and having an air inlet above said chamber, a fuel passage from the chamber to the conduit, said conduit having an orice discharging into said outlet pipe beneath said chamber, means conducting secondary air radially and inwardly to the annular space surrounding the primary mixture orice, deecting vanes in said means for causing whirling of said secondary air in one direction, a throttle valve including a shaft carrying a blade of helical form mounted transversely in the suction pipe, th-e edges of the blade bearing accurately against the inner Wall of the outletipipe in the closed position of said valve, the pitch of the helical blade being such that it reinforces and prolongs the whirl of the air in said `one direction.

ETIENNE MARIE JULES LEPICARD.

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