CA1040032A - Carburetor for an internal combustion engine - Google Patents

Abstract

INVENTION: CARBURETOR FOR AN INTERNAL COMBUSTION ENGINE

ABSTRACT OF THE DISCLOSURE

A carburetor for an internal combustion engine comprising a fuel chamber arranged in the mixing compartment of a suction tube and rotatable about the lower end of a fuel-infeed conduit secured in the mixing compartment by means of an impeller wheel rotatable in the sucked-up air current. The fuel chamber possesses at least one lateral nozzle for the delivery of fuel into the mixing compartment. A ring-shaped gap is provided in the fuel chamber between its inner wall and the stationary fuel-infeed conduit. By means of this gap a lower fuel compartment, into which opens the fuel-infeed conduit, communicates with an upper fuel compartment. The upper fuel compartment has a ring-shaped air inlet opening which is coaxially arranged with respect to the fuel-infeed conduit.

Description

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The present invention relates to a carburetor for an internal com-bustion engine which is of the type comprising a fuel chamber arranged in the mixing chamber of a suction tube and rotatable, by means of an impeller wheel rotating in the induced air current, about the outlet end of a fuel-infeed conduit disposed in the mixing chamber, and wherein the fuel chamber possess-es at least one lateral fuel ejection opening for delivering fuel to the mixing chamber.
Such type of carburetor as described for instance in Canadian patent specification No. 1,001,020 provides such a well prepared and properly proportioned fuel-air mixture for all operating conditions of the combustion engine that the quantity of noxious substances, such as C0 and CH, contained in the exhaust gases is considerably below the permissible threshold value.
However, measurements undertaken on different ~ehicles of the proportion of C0 and CH, the engine efficiency and the fuel consumption and extensive check-ing of the manner of driving a vehicle equipped with such carburetor have shown that 1aws can still exis~. Typical of these are unsatisfactory idling performance, undesirable amounts of C0 at low or intermediate rotational speeds, and insufficient C0 in the full load range where usually it is con-sidered advantageous to have a C0-content even if of relatively small magni-tude, and so forth.
The present invention consists in a carburetor for an internal com-bustion engine, comprising a mixing chamber through which intake air flows, a fuel-infeed conduit possessing an inlet part fixedly disposed within the mixing chamber and provided with a fuel inlet opening connectable to a fuel delivery line leading to a fuel supply outside of the mixing chamber and possessing a straight outlet part extending coaxially with the mixing chamber in the direction of the intake air flow and provided at its downstream end with a fuel outlet opening, a rotor cooperating with the straight outlet part of the conduit, and an impeller for rotating the rotor about the downstream end of the straight outlet part of the conduit and about an axis defined by - 1 - ~

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the outlet part; the rotor including: a fuel compartment having a bottom disposed downstream of the fuel outlet opening and extending between the bottom and the fuel outlet opening of the conduit; at least one lateral fuel ejection opening disposed from the outlet opening at a distance greater than an outer diameter of the straight outlet part of the conduit; and fuel flow channel means or manifold connecting each fuel ejection opening with the fuel compartment, wherein the fuel flow manifold has between the fuel compartment and each fuel ejection opening a section extending parallel to the axis of rotation and wherein an annular gap between the straight outlet part of the fuel-infeed conduit and an adjacent surface of the rotor is situated and dimensioned to prevent fuel in the fuel compartment and in the fuel flow manifold from passing the gap when the rotor is rotating about the axis of rotation.
In a preferred construction of carburetor the rotor incorporates a housing having a housing wall, and within the housing there is provided between the housing wall and the straight outlet part of the fuel-infeed conduit the annular gap. The length of the annular gap is greater than the outer diameter of the straight part of the fuel-infeed conduit and the dia-meter of the uel compartment which is coaxial with the outlet part of the 2Q fuel-infeed conduit is smaller than the external diameter of the outlet part.
At least one tubular fuel flow channel leads laterally away from the fuel compartment to a fuel ejection opening, the fuel ejection opening being a metering noz~le for delivering a quantity of fuel which is approximately proportional to the square root of the fuel pressure in the fuel channel.
In such a construction the diameter of the fuel compartment is preferably substantially equal to the diameter of the fuel outlet opening of the fuel-infeed conduit. The tubular fuel flow channel may possess an inter-mediate section which is parallel to the axis of rotation of the fuel chamber housing and the diameter of which intermediate section is not greater than the diameter of the fuel compartment and is greater than the diameter of the ~O~OQ3Z
fuel ejection opening. The tubular fuel flow channel may also include a starting section which extends from the fuel compartment to the intermediate section of the fuel flow channel and a terminal or end section which extends from the intermediate section to the fuel ejection opening. The starting section and terminal section may each be located in a plane substantially prependicular to the rotational axis of the fuel chamber housing and prefer-ably be radially directed. In this respect it is particularly advantageous if the starting section, the intermediate section and the terminal section of the fuel flow channel have substantially the same diameter and such dia-meter is equal to or at most is 10 percent smaller than the diameter of thefuel compartment. In order to atomize fuel ejected from a fuel ejection opening it is possible to arrange in fr~nt of the fuel ejection opening an atomizer device, comprising, for example, a spray edge. The provision of an atomizer device is especially advantageous in those cases where the dia-meter of the fuel ejection opening needed for the delivery of the required quantity of fuel is too large to achleve a proper atomization of the fuel.
Generally by providing a single fuel ejection opening there can be realized optimum preparation of the fuel-air mixture. If, for instance, there are re~uired for this purpose two fuel ejection openings then the latter are advantageously arranged at different positions along the fuel chamber housing and angularly spaced from each other either by 180 or by any other angle.
In order that the invention may be more readily understood, refer-ence will now be made to the accompanying drawings, in which:-Figure 1 is a schematic illustration in longitudinal section ofone embodiment of carburetor according to the invention comprising a fuel chamber rotatable about a fuel-infeed conduit and having fuel ejection open-ings arranged in communication with the fuel distribution compartment, and wherein the impeller wheel has been omitted to simplify the illustration;
Figure 2 is a longitudinal sectional view of a second embodiment of carburetor having a fuel chamber with impeller wheel and having fuel ejec-I ~' J!`

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tion openings arranged in communication with the annular fuel flow channel, Figure 3 is a longitudinal sectional view along the line III-III
of Figure 3a of a third embodiment of carburetor having a fuel chamber where-in the annular fuel flow channel between the fuel distribution and fuel com-partments serves for fuel metering;
Figure 3a is a top plan view of the fuel chamber of Figure 3;
Figure 4 is a longitudinal sectional view of a fourth embodiment of carburetor having a fuel chamber similar to that of Figure 3, however, having additional tubular fuel flow channels for idling;
Figure 4a is a plan view of the fuel chamber of Figure 4;
Figure 5 is an enlarged fragmentary sectional view of the region of a fuel chamber encompassing a fuel ejection opening and constituting a modification of figure l;
Figure 6 is a longitudinal sectional view of a fifth embodiment of a fuel chamber;
Figure 7 is a schematic illustration of a carburetor according to the invention including the mixing chamber;
Figure 8 is a longitudinal sectional view through a sixth embodi-ment of carburetor having a fuel chamber housing with one fuel ejection opening;
Figure 9 is a longitudinal sectional view through a seventh embodi-ment of carburetor having a fuel chamber housing with two fuel ejection openings on opposite sides of the housing axis; and Figure 10 is a cross-sectional view of a modification of the embodi-ment of Figure 9 along the line X-X in Figure 9 wherein the fuel chamber housing has two fuel ejection openings, the angular spacing of which is less than 180.
Describing now the drawings, firstly it is to be understood that a fuel-infeed conduit with a coaxial fuel chamber rotating thereabout and an 3Q impeller wheel are arranged in a mixing chamber of the engine between an air ~ , .
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~04Q(~32 filter and a control valve or flap.
In the embodiment illustrated in Figure 1 the fuel chamber 2' is contained in a substantially cylindrical rotor or housing 2 which has a floor or bottom 2a and which is rotatably mounted adjacent its upper open end by means of a ball bearing 3 on a straight fuel outlet part 1 of the fuel-infeed conduit. The straight fuel outlet part, which hereinafter will be referred to as the fuel-infeed conduit 1, is widened at its outlet opening la into an enlarged portion 4 which extends close to the inner wall of the rotor 2 in order to form a substantially annular fuel flow channel 5 between the fuel-infeed conduit 1 and the rotor 2. The end surface 4b of the enlarg-ed portion 4 is spaced from the rotor floor 2a, to provide therebetween a compartment which hereinafter will be referred to as the fuel compartment 6.
The rotor or housing 2 contains an insert member 9 having a trans-verse wall 9a between the ball bearing 3 and the enlarged portion 4 which surrounds the fuel-infeed conduit 1 and forms therewith an annular gap 8.
Between the transverse wall 9a and the enlarged portion 4 there is thus provided in the fuel chamber 2' a further compartment which will be referred to hereinafter as the manifold or fuel distribution compartment 7. This fuel distribution compartment 7 thus is in communication via the annular fuel flow channel S with the fuel compartment 6 and with the mixing chamber via the annular gap 8 and an opening 11 of the ball bearing 3. The transverse wall 9a i5 adequately spaced from the ball bearing 3 and between both of these components there is present an aeration compartment 12. No seal is provided between the fuel-infeed conduit l and the fuel chamber housing 2, so that for resisting the rotation of the fuel chamber there is only the friction of the ball bearing. Immediately below the transverse wall 9a there are provided in the fuel chamber housing 2 a number of fuel ejection openings lO which in the embodiment of Figure 1 are constituted by radial nozzles having an opening diameter in the order of tenths of a millimeter. What is important for the proper operation is that the inner diameter of the annular fuel flow channel ~1 `

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5 is greater than the outer diameter of the annular gap 8.
It is assumed that the fuel level N lies in the fuel distribution compartment 7 of the fuel chamber housing 2 when this housing is not rotating.
When the fuel chamber housing 2 begins to rotate then the fuel ascends along the chamber wall and the fuel surface assumes the configuration of a parabol-oid of revolution, generally indicated by reference character 13. At high rotational speeds there is formed in the fuel disLribution compartment 7 a fuel layer 14 bearing against the inner wall of the compartment~ the thickness of which is determined by the width of the annular fuel flow channel 5 and the fuel compartment 6 continually remains filled with fuel. The fuel level N must be at least such that the lower end of the fuel-infeed conduit 1 is immersed in the fuel. The supply of fuel into the mixing chamber through the nozzles 10 is metered as a function of the rotational speed of the fuel chamber housing 2. It should be readily apparent that with this embodiment the insert member 9 also can be omitted if the diameter of the piston-shaped enlarged portion 4 can be made larger than the diameter of the ball bearing opening ll, in which case the ball bearing opening 11 constitutes the annular gap.
In the embodimellt illustrated in Figure 2 the fuel ejection openings 2a la are arranged at a distance above the fuel compartment 6 of the fuel chamber housing 2 which carries an impeller wheel 16. The fuel chamber housing 2 com-prises at its lower end a cylindrical container 2b, the inner diameter of which need not be appreciably larger than the outer diameter of the fuel-infeed conduit 1 which protrudes into the container 2b. Mounted on the con-tainer 2b are laterally extending small tubes or pipes 15 containing at their outer ends the fuel ejection openings or nozzles lO. The piston-shaped en-larged portion 4a of the fuel-infeed conduit 1 is located above the small tubes or pipes 15. An annular fuel flow channel 5 extends from the fuel com-partment 6 to the tubes 15 and between the enlarged portion 4a and the inner 3Q wall of the fuel chamber housing to an insert 9 located between the enlarged .~ , ~04~)Q32 portion 4a and ball bearing 3. The insert 9 serves for forming the annular gap 8 which can have a very small width.
The aeration compartment 12 is in communication with the mixing chamber via the annular gap 8 an additional aeration compartment 12' between insert 9 and ball bearing 3 and the opening 11 in the ball bearing 3. This embodiment is especially suitable for compact or small carburetor construc-tions. In this case the fuel level N is located in the fuel compartment 6 between the nozzles 10 and an outlet opening la of the fuel-infeed conduit 1 when the fuel chamber housing is not rotating. With the fuel chamber housing

2 rapidly rotating there is formed in the aeration compartment 12 a layer of fuel bearing against the wall, and the thickness of this layer is governed by the width of the section 5' at the annular fuel flow channel 5. The delivery of fuel into the mixing chamber through the nozzles 10 is again metered as a function of the rotational speed of the fuel chamber housing 2.
In the embodiment shown in section in Figure 3 and in plan view in Figure 3a the fuel chamber housing 2 comprises a metallic body or body member 2c having a relatively long central bore 2d. The fuel-infeed conduit 1 ex-tends almost to the bore base or floor 2e, so that between these two compon-ents there is a small fuel compartment 6. At a relatively large spacing from the bore base 2e the metallic body 2c possesses, for instance, four con-tinuous bores lOb, the outer openings of which constitute the fuel ejection openings lOa of the fuel chamber housing 2. At the inner end the bores lOb are for instance conically widened, the conical widened portions forming the fuel distribution compartment 7 of the fuel chamber. The fuel-infeed conduit 1 from the region of its outlet opening la up to approximately the center of the radial bores lab possesses a diameter which is only slightly less than the inner chamber diameter. Hence, the annular fuel flow channel 5a between the fuel compartment 6 and the fuel distribution compartment 7 has a length several times its diameter, and the width of the annular fuel flow channel 5a is smaller than the diameter of the outlet opening la of the fuel-infeed con-~O~ 3Z
duit 1. The diameter of the bores lOb is greater than the width of the fuelflow channel 5a. Above the section lb of the fuel-infeed conduit extending up to the radial bores lOb the fuel-infeed conduit 1 has a somewhat smaller diameter, so that the annular opening 8' between such tubular portion and the chamber wall is wider than the annular fuel flow channel 5a. There is inserted into the opening 8' a socket or sleeve 18 in order to obtain an annular gap 8, the diameter of which, as previously described, is smaller than that of the annular fuel flow channel 5a.
The fuel level N should be located slightly above the opening la of the fuel-infeed conduit 1 when the fuel chamber is not rotating. When the fuel chamber rotates the fuel ascends out of the lower fuel compartment 6 through the annular fuel flow channel 5a into the fuel distribution com-partment 7 and at this location is withdrawn outwardly by the centrifugal force to the fuel ejection openings lOa through the bores lOb and atomized at the ejection openings lOa. Moreover, air is sucked through the annular opening 8' and through the annular gap 8 so that there is already delivered by the ejection openings lOa a fuel-air-mixture into the mixing chamber and it has been ound that this is very advantageous for the preparation of the fuel-air mixture. Decisive for the fuel metering are the length and width of the annular fuel flow channel 5a.
If this carburetor of Figure 3 is dimensioned for particularly low values of the content of CO- and CH-noxious substances it can happen that the obtained fuel-air-mixture is too lean for engine idling. Figures 4 and 4a respectively shown in section and plan view an embodiment which overcomes this defect. The fuel-infeed conduit 1 and the fuel chamber housing 2 with the bores lOb ~Figure 4a) radially leading away from the fuel distribution compartment and the lang and narrow annular fuel flow channel 5a are in this case constructed as in the embodiment of Figure 3. The fuel compartment 6 ~Figure 4) is downwardly extended by a, for instance, frusto-conical recess 3Q or depression 6a. Leading from this recess or depression 6a are for instance ~4(JQ;~Z
two diametrically opposed tubular fuel flow channels 17 through the metallic body 2c of the fuel chamber housing to additional fuel ejection openings 17b, 17d, which, in the illustrated fuel chamber, are located at the same height as the bores lOb. With low rotational speed fuel also reaches the recess or depression 6a of the lower fuel compartment 6 and from that location flows through the tubular fuel flow channels 17 to the additional fuel ejection openings 17b, 17d where it is atomized. In order to meter the additional fuel delivery the tubular charmel orifice located in the coaxial recess 6a and connected with channels 17 by a radial channel section 17d or the fuel ejection opening can be constructed as a nozzle with narrower cross-section, as illustrated at 17a and 17d. The additional fuel ejection openings 17b, 17d can also be arranged lower than the fuel ejection openings lOa.
As mentioned with the chamber construction of Figure 3 the air infeed to the fuel which occurs prior to atomization is particularly advan-tageous. This can also be provided with other constructions of fuel chambers.
Thus, in Figure 5 there is shown on an enlarged scale a fragmentary section o t~e fuel chamber of Figure l containing the fuel ejection opening or nozzle 10 and where certain modifications will be apparent. Between the ball bearing

3 and the insert member 9 ~here is located the aeration compartment 12 and below the insert member 9 the fuel distribution compartment 7. The nozzle lO
leads to an enlarged bore 19 in the chamber wall and this bore 19 is connected by means of an air channel 20 with the aeration compartment 12. With the fuel compartment rotating the fuel is dispensed out of the nozzle lO and air out of the air channel 20 into the enlarged bore 19 and at the opening lO'a of the last-mentioned bore, there occurs a further atomization of the fuel by the nozzle 10.
With the embodiment shown in longitudinal sectional view in Figure 6 the fuel chamber housing 2 consists of an inner fuel chamber housing 21 and an outer fuel chamber housing 22. The inner fuel charnber housing 21 is essential-0 ly constructed as previously described and contains the fuel compartment 6_ 9 _ 104~3~
into which opens the fuel-infeed conduit 1, the annular gap 8, and the aeration compartment 12. With the illustrated embodiment the fuel-infeed conduit 1 is smooth and does not possess any enlarged portion. The aeration compartment 12 is in the form of a cylindrical hollow compartment or space.
The outer fuel chamber housing 22 surrounding the inner fuel chamber housing 21 forms together therewith the annular fuel flow channel 23 which communi-cates via lateral bores 25 in the inner ~uel chamber 21 with the fuel com-partment 6. The outer diameter of this annular fuel flow channel 23 is greater than the diameter of the fuel compartment 6 in the inner fuel chamber housing 21. The head portion 22a of the outer fuel chamber housing 22 con-tains, for instance, four radial bores 24 by means of which the annular fuel flow channel 23 is connected with the nozzles lO. When the fuel chamber is not rotating, the fuel level N is located between the outlet opening la of the fuel-infeed conduit 1 and the nozzles 10. Above the fuel level N it is possible for radial bores 26 to lead from the aeration compartment 12 of the inner fuel chamber housing 21 to the annular fuel flow channel 23.
When the fuel chamber housing 2 begins to rotate then the fuel in the annular fuel flow channel 23, due to its greater diameter, climbs quicker than in the fuel compartment 6 and by means of the lateral bores 25 in the inner fuel chamber housing 21 there is realized a pump effect so that fuel is withdrawn out of the fuel compartment 6 into the fuel flow channel 23.
Equally, fuel can flow through the bores 26 provided as an aid into the fuel flow channel 23. It has been found that such a construction of the fuel chamber --which is advantageous in terms of manufacture-- is insensitive to fluctuations of the fuel level and that also no fuel penetrates through the annular gap 8.
In Figure 7 there is schematically illustrated a preferred embodi-ment of the entire carburetor arrangement. A tubular stud or connection 27, forming a part of the suction conduit of the engine, carries a housing block 28 with the fuel supply for the carburetor. In order to maintain the level q of the fuel there can be provided a float mechanism which, if necessary can be constructed such that the fuel level in the fuel chamber only slightly varies throughout the entire inclination range of the vehicle which arises in practice. A bushing or sleeve 29 which fits into the tubular stud or connection 27 carries on, for instance, three radial struts 30 the fuel in-feed conduit 1 which is coaxial to the bushing and downwardly directed. The fuel-infeed conduit 1 is equipped with the fuel chamber housing 2 and the impeller wheel 16. In the simplest case a strut or web 30a is a tubular element, the inner end of which is connected with the fuel-infeed conduit 1 and at its outer end there is connected by means of a screw connection 31 a fuel line 32 leading to the fuel supply in the housing block 28. Such con-struction of the carburetor arrangement allows for a simple accommodation to different engine models, it only being necessary to dimension differently the bushing or sleeve 29.
The followng described embodiments are particularly insensitive to fluctuations o fuel level.
With the ~mbodiment of Pigure 8 a cyclindrical fuel chamber-housing block 2c, for instance Formecl of aluminum~ contains an axial blindhole bore 2f extending from the top towards the bottom and stepped once in diameter.
The lower portion of such bore which possesses the smaller diameter forms the uel compartment 6 and the upper portion serves for receiving the fuel-infeed conduit 1 and has a diameter which is not much greater than the outer diameter of the fuel-infeed conduit 1. Hence, between the fuel-infeed conduit 1 and the bore wall 2g there is present an annular gap 8 which has, for instance, a width of approximately 0.1 millimeter. Pushed onto the fuel chamber-housing block 2c is a plactics impeller wheel 16 and the entire assembly is supported in ball bearings 3 for rotation about the fuel-infeed conduit 1 and mounted by means of radial struts or webs 30 in a tubular stud or connection 27 or equivalent structure which is inserted in the mixing chamber in the suction 3Q conduit of the combustion engine. The upper part of the bore 2f intended to : `~ 3 Q~P32 receive the lower end of the fuel-infeed conduit 1 has a depth which is several times the outer diameter of the fuel-infeed conduit 1. The lower part or portion of the bore 2f forming the fuel compartment 6 has a diameter which is equal to the diameter of the fuel outlet opening la. Internally of the housing block 2c a tubular fuel flow channel 17 leads from the fuel com-partment 6 to a fuel ejection opening or nozzle 10 located in the housing block above vanes 16a of the impeller wheel 16. The tubular fuel flow channel 17 has three sections or portions, namely: a starting section 17e leading radially away from the fuel compartment 6l an intermediate section 17f which is parallel to the axis of rotation 33 of the housing block 2c, and an end or terminal section 17g which is radially terminated by the nozzle 10. The individual channel sections 17e, 17f, 17~ are constituted by bores in the housing block 2c. The nozzle 10 is a metering nozzle which preferably has the shape of a standard nozzle and the diameter of which governs the delivered quantity of fuel.
The end section 17~ of the fuel channel 17 is dimensioned such that the quantity of fuel delivered by the nozzle lO is approximately proportional to the square root of the fuel pressure at the nozzle inflow. The intermedi-ate section 17f of the fuel chamlel 17 has a diameter which is not greater than the diameter of the lower fuel compartment 6 and is greater than the diameter of the fuel ejection opening of nozzle 10. The diameter of the radial starting section 17e of the fuel channel 17 is not smaller than the diameter of the intermediate section 17f of the fuel channel. The starting section 17e, the intermediate section 17f and the end or terminal section 17g of the fuel channel 17 can have the same diameter as the lower fuel compart-ment 6 or their diameter is, for instance, up to 10 percent smaller than the diameter of the fuel compartment. According to one carburetor model the different diameters had, by way of example and not limitation, the following values: Inner diameter of the fuel-infeed conduit l = diameter of the fuel compartment 6 = diameter of the starting section 17e of the fuel channel / -~L04~3Z
17 = diameter of the intermediate section 17f thereof = diameter of the end section 17~ of the fuel channel = 1.6 millimeters; diameter of the fuel ejection opening 10 = 0.5 millimeters.
For an additional atomization of the fuel-spray jet emanating from the nozzle 10 the housing block 2c carries an atomizer device 34, preferably in the form of a spray edge. With the embodiment of Figure 8 the atomizer device 34 consists of a ring 35, for example, formed integrally with the impeller wheel 16 and which surrounds at a certain spacing the housing block 2c. The ring spacing and the ring height over the nozzle axis govern the degree of atomization. The fuel level N is adjusted between the outlet opening la of the fuel-infeed conduit 1 and the nozzle 10 when the housing block 2c is not rotating.
When the housing block 2c is placed into rotation by the impeller wheel 16 then fuel ascends in the tubular fuel channel 17 to the nozzle 10 and is metered by the latter and atomized as fine droplets by the atomization device 34 and delivered into the mixing chamber. In this connection the following relationships are present: (a) the rotational speed of the fuel compartment 6, the tubular fuel channel 17 and the nozzle 10 are approximate-ly~proport~onal to the quantity of air sucked per unit of time; (b) the fuel pressure in front of the nozzle 10 owing to the centrifugal force is approxi-mately proportional to the square of the rotational speed, and (c) the quantity of fuel delivered by the nozzle 10 per unit of time is approximately proportional to the square root of said fuel pressure, so that the fuel quantity delivered per unit of time is always proportional to the quantity of air sucked-in per unit of time.
Notwithstanding the very simple construction and the relatively small size --Figure 8 is an enlarged view-- the results which can be obtained wit~ such a carburetor are surprisingly good. It has been found that the increase of the C0-content desired with :Eull load is present with increasingly greater rotational speeds, the greater the spacing a of the axially parallel 1~4¢)~
intermediate section 17E of the fuel channel 17 from the rotational axis 33, so that such CO-increase can be realized without difficulty at a predeter-mined desired rotational speed.
Figure 9 illustrates a variant of the carburetor arrangement where-in the fuel chamber-housing block 2c is equipped with two fuel ejection openings or nozzles 10, 10' arranged on opposite sides of the housing axis.
Leading from the fuel compartment 6 to each nozzle 10 and 10' is a respec-tive tubular fuel flow channel 17 and 17', which can be constructed like the fuel flow channel of the embodiment of Figure 8, i.e. both of the fuel channels 17 and 17' each consist of a radial starting section 17e and 17'e respectively, an axially parallel intermediate section 17f and 17'f respec-tively, and a radial end section 17~ and 17'g. One nozzle 10' is closer to the impeller wheel 16 than the other nozzle 10. In this case the atomizer or atomization device 34 provided for the atomization of the fuel jet deliv-ered by the nozzles 10, 10' consists of a cap member 36 placed upon the housing block 2c and which extends to a point below the nozzle 10' and at the region of the nozzles 10, 10' possesses a respective section for forming a spray or spraying edge 37.
Figure 10 illustrates a section through a modification of the car-buretor of Figure 9 along the line X-X, wherein however the two nozzles 10, 10' are at an angular spacing of less than 180, for instance 90. In Figure 10 reference character 10 designates the upper nozzle and reference character 10' the lower nozzle. The cylindrical housing block 2c contains the fuel compartment 6 from which the tubular fuel flow channels 17, 17' lead to the nozzles 10, 10'. The housing block 2c carries the impeller wheel 16 with the vanes 16a and the ring-shaped attachment or extension 35 serving for the atomization of the delivered fuel jet.
It should be readily apparent that the previously described car-buretors, with essentially the same basic construction, can be readily accom-modated in different engine models by providing an appropriate number of _ 14 --~al40(~3;2 nozzles, construction of the fuel channels and dimensions. In particular the atomization with an atomizer device can also be omitted if with higher rotational speeds and smaller nozzle diameter there is realized a satisfac-tory atomization of the fuel. In order to obtain a small constructional height or length of the carburetor, it is advantageous to arrange the impel-ler wheel 16 at the housing block 2c below the nozzle~s). However the impel-ler wheel can, alternatively, be arranged above the nozzles.
It has been found that also with the lowest content of noxious sub-stances in the exhaust gases there can be obtained an increased efficiency of the engine This means that optimization is possible for the content of noxious substances and engine effîciency, so that subsequent modifications, which on known carburetors are often carried out to obtain-at the cost of low content of noxious substances-a better efficiency of the engine are no longer of interest and can be dispensed with. The carburetor also does not contain any adjustable adjustment means, so that there i5 also dispensed with a need for frequent readjustment of the carburetor. A notable advantage~af the previously described carburetor constructions further resides in the fact that there is not required an~ accelerator or booster pump.

Claims (22)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A carburetor for an internal combustion engine, comprising a mixing chamber through which intake air flows, a fuel-infeed conduit possessing an inlet part fixedly disposed within the mixing chamber and provided with a fuel inlet opening connectable to a fuel delivery line leading to a fuel supply outside of the mixing chamber and possessing a straight outlet part extending coaxially with the mixing chamber in the direction of the intake air flow and provided at its downstream end with a fuel outlet opening, a rotor cooperating with the straight outlet part of the conduit, and an impeller for rotating the rotor about the downstream end of the straight outlet part of the conduit and about an axis defined by the outlet part;
the rotor including: a fuel compartment having a bottom disposed downstream of the fuel outlet opening and extending between the bottom and the fuel outlet opening of the conduit, at least one lateral fuel ejection opening disposed from the outlet opening at a distance greater than an outer diameter of the straight outlet part of the conduit; and fuel flow channel means or manifold connecting each fuel ejection opening with the fuel compartment, wherein the fuel flow manifold has between the fuel compartment and each fuel ejection opening a section extending parallel to the axis of rotation and wherein an annular gap between the straight outlet part of the fuel-infeed conduit and an adjacent surface of the rotor is situated and dimen-sioned to prevent fuel in the fuel compartment and in the fuel flow manifold from passing the gap when the rotor is rotating about the axis of rotation.

2. A carburetor as claimed in claim 1, wherein the fuel flow channel means or manifold includes an annular fuel flow channel connecting the fuel compartment with a fuel distribution compartment with which each said fuel ejection opening is in communication and wherein the annular gap has an outer diameter smaller than an inner diameter of the annular fuel flow channel.

3. The carburetor as claimed in claim 2, wherein the annular fuel flow channel connecting the fuel compartment with the fuel distribution compart-ment possesses a length several times its diameter and a width which is smaller than the diameter of the outlet opening of the fuel-infeed conduit, and wherein from the fuel distribution compartment there leads a respective radial bore to the or each said lateral fuel ejection opening, and the diameter of the bore is greater than the width of the annular fuel flow channel.

4. A carburetor as claimed in claim 3, wherein the fuel compartment possesses a recess which is substantially coaxially arranged with respect to the straight outlet part of the fuel-infeed conduit, and at least one tubular fuel flow channel leads from the recess to means defining an additional fuel ejection opening.

5. A carburetor as claimed in claim 4, wherein the tubular fuel flow channel has an orifice located in the coaxial recess of the fuel compartment which orifice is different in size from that of said fuel ejection opening of the tubular fuel flow channel.

6. A carburetor as claimed in claim 5, wherein said orifice is smaller than the fuel ejection opening of the tubular fuel flow channel.

7. A carburetor as claimed in claim 5, wherein said orifice is larger than the fuel ejection opening of the tubular fuel flow channel.

8. A carburetor as claimed in claim 1, wherein the rotor incorporates a housing having a housing wall, and within the fuel chamber-housing there is provided between the housing wall and the straight outlet part of the fuel-infeed conduit the annular gap, the length of the annular gap being greater than the outer diameter of the straight outlet part of the fuel-infeed conduit, and the diameter of the fuel compartment which is coaxial with the outlet part of the fuel-infeed conduit is smaller than the external diameter of the outlet part, and at least one tubular fuel flow channel leading laterally away from the fuel compartment, to a fuel ejection opening, the fuel ejection opening being a metering nozzle for delivering a quantity of fuel which is approximately proportional to the square root of the fuel pressure prevailing in the fuel flow channel.

9. A carburetor as claimed in claim 8, wherein the fuel compartment has a diameter which is substantially equal to the diameter of the fuel out-let opening of the fuel-infeed conduit.

10. A carburetor as claimed in claim 8, wherein the tubular fuel flow channel possesses an intermediate section parallel to the axis of rotation of the rotor, the diameter of the intermediate section not exceeding the diameter of the fuel compartment and being greater than the diameter of the fuel ejection opening.

11. A carburetor as claimed in claim 10, wherein the tubular fuel flow channel further includes a starting section extending from the fuel compart-ment to the intermediate section of the fuel flow channel, said starting section being located in a plane which is substantially perpendicular to the axis of rotation of the fuel chamber-housing and having a diameter which is not smaller than the diameter of the intermediate section of the fuel flow channel.

12. A carburetor as claimed in claim 10, wherein the tubular fuel flow channel further includes a terminal section which extends from the intermediate section of the fuel flow channel to the fuel ejection opening, said terminal section being located in a plane which is substantially perpendicular to the axis of rotation of the rotor and having a diameter which is greater than the diameter of the fuel ejection opening.

13. A carburetor as claimed in claim 11, wherein the tubular fuel flow channel further includes a terminal section which extends from the inter-mediate section of the fuel flow channel to the fuel ejection opening, said terminal section being located in a plane which is essentially perpendicular to the axis of rotation of the rotor and having a diameter which is greater than the diameter of the fuel ejection opening, and wherein selectively at least the starting section, the terminal section, or both such sections of the fuel flow channel, extend in radial direction.

14. A carburetor as claimed in claim 8, wherein the tubular fuel flow channel includes a starting section, an intermediate section and a terminal section which each have substantially the same diameter and which diameter is equal to the diameter of the fuel compartment.

15. A carburetor as claimed in claim 8, wherein the tubular fuel flow channel includes a starting section, an intermediate section and a terminal section each of which have a diameter which at most is 10% smaller than the diameter of the fuel compartment.

16. A carburetor as claimed in claim 8, wherein there is provided a single fuel ejection opening.

17. A carburetor as claimed in claim 8, wherein there is provided two of said fuel ejection openings, and a respective tubular fuel flow channel leading from the fuel compartment to each said fuel ejection opening.

18. A carburetor as claimed in claim 17, wherein the fuel ejection openings are spaced at a different position along the fuel chamber housing.

19. A carburetor as claimed in claim 8, further including an atomizer device arranged in from of each fuel ejection opening in order to atomize the fuel which is delivered by at least one of the fuel ejection openings.

20. A carburetor as claimed in claim 19, wherein the atomizer device comprises spray edge means rotating in use with the rotor.

21. A carburetor as claimed in claim 19, wherein the rotor comprises a substantially cylindrical block possessing an axial blindhole bore for the reception of the straight outlet part of the fuel-infeed conduit and for forming the fuel compartment and bores for the tubular fuel flow channel leading from the fuel compartment to the fuel ejection opening.

22. A carburetor as claimed in any of claims 19, 20 and 21, wherein the rotor comprises a substantially cylindrical block, the atomizer device comprises ring means which at the region of each fuel ejection opening surrounds at a certain spacing the cylindrical rotor block.