US3348824A - Automatic arrangement for a carburetor - Google Patents

Description

Filed June 3, 1966 O t/24. 1 JEAN-PIERRE SOUBIS 3,348,324

AUTOMATIC ARRANGEMENT FOR A CARBURETOR 3 Sheets-Sheet 1 INVENTOR Fig.5

ATTORNEYS" JEAN-PIERRE SOUBIS 3,348,824 AUTOMATIC ARRANGEMENT FOR A CARBURETOR 3 Sheets-Sheet 2 Filed June 3, 1966 N YS.

,1967 JEAN-PIERRE SOUBIS 3, 8,8

AUTOMATIC ARRANGEMENT FOR A CARBURETOR Filed June 3, 1966 3 Sheets-Sheet 3 Z INVENTOR' Jam Frre 504(5/3 Mafia {M 3 6 10% ATTORNEYS United States Patent Ofi 3,348,824 Patented Oct. 24, 1967 Free AUTOMATIC A 2 3 Claims. (Cl. 261-41) 10 ABSTRACT OF THE DISCLOSURE An automatic arrangement for the carburetor of an internal combustion motor wherein the main inlet pipe is provided with a main venturi. A rotating control element controls the volume of gas admitted into such pipe. The carburetor is provided with a jet having a cooperating needle. A rod support is rotated about its axis as a function of the rotation of the above control elements. A cam track has an internal bore through which the rod support passes and is adapted to allow the cam track to slide freely along the rod support. Means are provided for driving said cam track in rotation by the rod support and means are provided controlling the sliding of the cam track as a function of the depression prevailing in the main inlet pipe downstream from the rotating control element. A feeler cooperating with the needle is applied against the cam track by elastic means. An auxiliary feed pipe is provided for admitting air and a channel extends into such auxiliary feed pipe for feeding motor fuel to the air admitted in the auxiliary pipe. Means are provided for controlling the motor fuel feeding the auxiliary pipe operating in response to the depression prevailing in the main inlet pipe at the level of the neck of the main venturi.

This invention relates to an automatic arrangement for a carburetor assuring an exact automatic regulation of the richness of the motor fuel for feeding the motor in accordance with the operating conditions thereof.

Generally, combustion motors with exterior carburetion comprise an admission pipe for the motor fluid into one or more cylinders. With this admission pipe there is associated a choke or venturi diminishing locally the crosssection of the pipe and a valve or butterfly valve controlling the flow of working fluid admitted into one or more cylinders, that is to say the rate of feed to the latter.

The operating fluid entering into a combustion chamber through the inlet pipe is a carbureted mixture obtained by feeding the pipe with air and securing a pulverization or emulsion of the liquid fuel, either in such pipe itself, at the level of the choke neck, by means of an appropriate carburetor arrangement, or in a separate auxiliary pipe, called a secondary or carburetion pipe, which opens into the inlet pipe downstream of the butterfly valve associated therewith. 0

There are also feed processes that can be qualified as heterogeneous, in opposition to the usual feed process, indicated above, according to which the motor is fed with a homogeneous carbureted fluid. In these heterogeneous feed processes the combustion chamber is fed by two 5 distinct flows of different richness.

For example, in accordance with such a heterogeneous feed described in Patent 3,087,480 granted Apr. 30, 1963, to J. Baudry, the inlet pipe feeds the combustion chamber with non-carbonated air and a rich carbureted mixture is introduced simultaneously into such chamber through a secondary separate pipe which, this time, does not discharge into the preceding, but directly into the combustion chamber through an orifice distinct from that of the inlet pipe for air. These two orifices are uncovered by the same inlet valve during the suction phase of the motor and the end of the secondary pipe is oriented towards the electrodes of the sparkplug.

Whatever may be the feed process chosen it is necessary to adapt the richness of the admitted mixture to the various conditions for the operation of the motor.

The arrangement according to the invention has for an object to secure in an exact way such adaption by automatic regulation of the richness of the motor fuel of a carbureted mixture feeding the motor (whether a homogeneous carburetion or a heterogeneous carburetion in the sense indicated above) as a function of the depression Ap prevailing in the combustion chamber and of the opening angle at of the butterfly valve controlling the volume of gas admitted (rate of inlet).

A given value couple (Ap, or) defines, in fact, an operating point of the motor, since the running speed N of the motor is then also fixed, Ap, or and N remaining connected by the same relation when the operating conditions may vary.

The arrangement according to the invention regulates automatically the fuel content of the feed of an internal combustion motor which comprises in the usual way a main inlet pipe and a rotating element such as a butterfly valve for controlling the rate of admission.

This arrangement is adapted to a carburetor provided with a jet and a needle which penetrates into the jet for limiting the cross-section of the passage for the motor fuel across the same, with elastic means such as a spring associated with said needle.

According to the invention one uses a rod fixed in rotation with the element controlling the rate of admission, a cam track or cam with three dimensions having an internal bore for said rod with a cross-section allowing the sliding of the cam track along said rod, which is moreover adapted to entrain in rotation the cam track when it is itself driven in rotation by the element controlling the rate of admission.

The cam track is associated with an arrangement controlling its displacement along said rod as a function of the depression prevailing in the main pipe of the motor, downstream of the rotating element controlling the rate of admission. The arrangement comprises also a feeler cooperating with said needle and applied against the cam track by elastic means associated with the needle.

The invention will be described below in greater detail referring to some examples of construction not in any limiting sense, illustrated in the drawings in which:

FIGURE 1 shows a top view with parts in cross-section of a carburetion arrangement according to the invention.

FIGURE l-a shows a cross section line aa of FIGURE 1 and a cylinder in the case of a hetereogeneous feed of the motor.

FIGURE 2 is a cross-sectional View on a larger scale of the cam track along section line aa of FIGURE 1.

FIGURE 3 is a perspective view of one way of constructing the rod upon which the cam track slides.

FIGURE 4 is an elevational view with parts in section showing one example of a construction for controlling the longitudinal displacements of the cam track.

FIGURE 5 is a schematic view showing a construction wherein the feeler is applied upon the profile of the cam track through the intermediary of a lever.

FIGURE 6 is a cross-sectional view similar to FIGURE 1a illustrating a modification.

FIGURE 7 is a perspective view of a device for consectional view taken along trolling the simultaneous rotation of the butterfly valve and of the cam track.

In the embodiment shown by way of example in FIG- URE 1a, the invention is used for the heterogeneous feed of a motor according to the process described in the above cited patent, without having any limiting character. A combustion chamber 1 is shown only partially having a piston 2, a cylinder 3 and a spark plug 4.

The inlet valve 5 is of the type described in application Ser. No. 435,427 filed Feb. 26, 1965, now Patent No. 3,331,361.

According to the process described in the above cited patent there is secured a heterogeneous feed of the combustion chamber 1 by admitting into said chamber through two separated conduits 32 and 38, two different fluids across two distinct orifices respectively, 12 and 34 uncovered by the same valve head 35 in the open position of the inlet valve 5.

One ofthe fluids admitted through the inlet conduit 32 is preferably noncarbureted air while that in the other conduit isa rich carbureted mixture.

The end portion 36 of the conduit 38 has such an orientation that it is directed towards the electrodes 37 of the spark plug in the open position of the inlet valve 5.

In this way one can maintain up to the moment of firing a suflicient local richness in the neighborhood of the electrodes in order to permit the combustion of the aggregate poor heterogeneous mixture admitted into the chamber 1 during the suction phase. The inlet conduit 32 is fed by air through the main pipe 6 in which such air arrives at the end 7 after having traversed a filter not shown.

The pipe 6 comprises a choke 8 reducing the cross section of the pipe locally and a main butterfly valve 9 which regulates the flow of air admitted into the chamber 1, this main butterfly valve. rotating about its axis 10.

Downstream fromthe main butterfly valve 9 controlling the rate of supplying the cylinder, the air admitted traverses the chamber 11 before flowing through the conduit 32 and the orifice 12 into the chamber 1 when the admission valve 5 is in open position.

The rich carbureted mixture which, upon its admission into the chamber 1 is, according to the process described in the above cited patent produced in the secondary pipe 13 and directed towards the electrodes 37 of the spark plug.

This pipe 13 is associated with a carburetor arrangement having an air admission conduit 14 comprising a secondary choke 15 in the neck of which is secured in the usual way a pulverization or emulsion of the liquid motor fuel. This latter is contained in the container 20 coming through the conduit 21 whose orifice 24 is controlled by the needle 23 fixed to the float 22, thereby maintaining the level of motor fuel in the container 20 constant.

The container 20 feeds a liquid motor fuel across the calibrated jet orifice 25 to the chamber 26 adjacent the container 20, the tube 27 having one end discharging at 28 into the neck of the secondary choke where it produces the pulverization or emulsion of the motor fuel into the air admitted through 14.

The flow of carbureted mixture (air+motor fuel) thus produced is controlled by the secondary butterfly valve 16 upon the axis 17, the control of this butterfly valve being synchronized with that of the main butterfly valve 9 by the usual system of rods and links connecting the axes of these two butterfly valves.

The pipe 13 into which the carbureted mixture flows is prolonged by a pipe 33 discharging through the orifice 41 into the bore of the guide 39 of the valve rod.

This rod has an axial conduit 38 communicating with an end conduit 36 located upon the internal face of the valve head 35 and making an elbow with the preceding. The axial conduit discharges into the bore of the valve guide 39 through an orifice 40.

The respective locations of the orifices 40 and 41 are chosen so that these orifices face one another in the opening position of the valve 5 (suction phase), thus then discharge ed when theinlet valve is in closed position as in FIGURE la when the orifices 40 and 41 are no longer face to face.

The element 42 fixed upon the guide 39 of the valve and being in contact with the flat 43 provided upon the rod of such valve is designed to prevent any rotation thereof which would have the effect of modifying the orientation of the conduit 36.

The conduit 29 establishing a communication between the upper portion of the chamber 26 and the choke neck 8 across the calibrated orifice 30 is designed, by creating in the chamber 26 downstream from the jet 25 a depression varying as that prevailing in the choke neck, to make the flow of fluid pulverized or emulsionated at 28 vary as the flow of air admitted into the motor by the main pipe 6.

Another calibrated orifice 31, establishing a communication between the chamber 26 and the pipe 14 makes the flow of fuel to vary only very slightly at 28 when the main butterfly valve 9 is closed progressively, without the orientation of the butterfly valve 16 being modified in spite of the increase of flow in the channel 13 which is produced then as a consequence of the higher depression in the combustion chamber. This system being adapted to start to progressively close the butterfly valve 16 in synchronism with the main valve 9, exclusively toward the end of the closing of this main valve, while the butterfly valve 16 is not driven in rotation with said main valve 9 for more open positions of the latter.

The axis 10 of the main butterfly valve 9 controlling the rate of feed to the cylinder is fixed upon the rod 44, as

seen in FIGURE 1, whereby rod 44 is rotated by butterfly valve 9 when the orientation of the latter is modified.

This rod 44 traverses a cam track or 3-dimensional cam 45 through a bore 46 provided in the cam track, as shown in FIGURE 2.

A pin 44a fixed to the rod 44 is guided by a slot 46a located in the the bore 46 parallel to the axis of the rod and assures the rotation of the cam track about the axis of such rod when the butterfly valve 9 rotates and allows the cam track to be displaced freely parallel to its axis. This rotation may also be obtained by giving to the rod 44 and the bore 46 appropriate complementary cross sections, the rod 44 having for example, the form shown in FIGURE 3, if the cross-section of the bore 46 is that of FIGURE 2.

In such example, meansformed by a depression capsule 47, whose compartment 48 communicates by the pipe 49 with the space 11, controls as a function of the depression prevaling in such space the displacements of the cam track parallel to the axis of the rod 44.

The cam track is fixed to the flexible membrane 5t) of the capsule 47 upon which the depression prevailing in the chamber 11 acts and which is subjected moreover to the action of one or more antagonistic springs 51.

The depression to which the capsule 47 is subjected is that prevailing downstream of the main butterfly valve 9 in the flow of fluid traversing through the main channel 6.

In place of a depression capsule it would be possible to use any other arrangement fulfilling the same function, for example the arrangement shown in partial cross-section in FIGURE 4 where the piston 18 is fixed to the cam track 45 and slides in the cylinder 19 whose bottom is connected to the main inlet pipe 6 of the motor downstream ofthe main butterfly valve 9 as the depression capsule of FIGURE 1.

A needle 56 sliding in an orifice 52 provided at the the chamber 1 along the base of the container 20 of the carburetor has a first end comprising a feeler 53 which is maintained in contact with the lateral surface of the cam track 45 by an elastic system formed by a spring 54 compressed between an abutment upon the rod 56 and the wall of the tank 20. The other end 55 of the needle 56 is tapered and cooperates with the carbureted jet orifice 25 of the carburetor controlling the cross section of such passage.

It is seen that if the cam track does not have a cylindrical form of revolution about its rod support 44 the cross section of the passage of the jet 25 and consequently the flow of pulverized or emulsated motor fluid at 28, will vary with the displacements of the needle 56 when the main butterfly valve 9 may turn, thus modifying the rate of feed to the cylinder and, when the cam track 45 should be displaced along the rod 44, as a function of the variations of the depression in the chamber 11.

In order to obtain according to the invention the exact automatic regulation of the richness of the carbureted mixture feeding the motor as a function of its load and its operation, it would sufiice therefore to give to the cam track the form corresponding to the optimal fiow of motor fuel for each value of the orientation angle a of the main butterfly valve 9 and each value of the depres sion Ap, each of said couples of values define, as has already been indicated, a point of operation of the motor since these values and the running speed N of the motor are interrelated.

This may be obtained by determining experimentally the position of the needle 56 giving the optimal richness for each couple oz, Ap defining an operational point of the motor and by noting the distance from the axis of the rod 44 of the feeler 53 for such position.

The form of the cam track 45 will be deduced from the measurements thus made.

In practice, in order to obtain the maximum of exactitude it would be suitable that the total travel of the needle 56 corresponds to a variation of cross section as slight as possible of the calibrated orifice 25 (this total travel being limited by the slope which should not be exceeded upon the cam track and the bulkiness of the device which should not be excessive). It is therefore advantageous to obtain a preregulation of the flow of motor fuel at 28, which in the particular case of a heterogeneous feed would correspond to an average richness of the heterogeneous mixture admitted into the chamber 1 close to the basic richness of a single homogeneous feed.

This rough preliminary operation can be obtained through the system formed by the chamber 26 communicating at its top through the conduit 29 with the neck of the choke 8, which as has been seen, by imposing downstream of the jet 25 a depression as a function of the air flow into the pipe 6, brings the flow of motor fuel under the control of the flow of air.

As shown in FIGURE 5 it would be possible to inter pose between the needle 56 and the feeler 53- a demultiplying lever 57 pivoted about a fixed point 58.

It is understood that the arrangement according to the invention of which a form of construction has been described in its application to a heterogeneous feed process for motors with exterior carburetion should not be limited to such a single application.

It can also be used in the case of a homogeneous feed with a single carbureted mixture, the arrangement being then controlled simultaneously by the rotation of a butterfiy valve controlling the rate of feed to one or more cylinders and the variations of the depression in these latter.

In order to obtain a homogeneous feed with the arrangement according to FIGURE let it is sutficient to replace the inlet valve 5 by a valve 5' of the usual type as shown in FIGURE 6-, eliminate pipe 33 and establish a communication 59 between pipes 6 and 13, for example, an orifice at the base of pipe 13 in order to permit the two flows to mix before entering into the combustion chamber 1. Such an arrangement according to the inven- 6 tion adapted to a homogeneous feed is shown in FIG- URE 6.

In the case of a homogeneous feed it should evidently be possible to eliminate completely the passage 13 and to retain only the main pipe 6 by causing the tube 27 of the carburetor to discharge into the neck of the main choke 8.

Nevertheless, in general, it may be preferred for a homogeneous feed to retain the assembly of the two pipes 6 and 13 from the arrangement of FIGURE 1a by adapting them to a homogeneous feed as illustrated in FIG- URE 6 By retaining a main pipe 6 for a homogeneous carburetion which is only a vehicle for the air it is possible to separate the functions for carburetion and for supply, the carburetion being efiected in the pipe 13 distinct from the main pipe 6 assuring the supply function. Consequently, there is for the main pipe 6 neither a limitation of the cross-section at the level of the choke 8, since there is no pulverization of the motor fuel in such pipe, nor any limitation of length or of volume between such choke and the inlet orifice into the combustion chamber since said pipe is not a medium for the motor fuel capable of condensing in such portion.

Under these conditions one can give to the main pipe 6 dimensions better adapted to secure an optimum feed of the combustion chamber in the range of operation provided for the motor, using the dynamic oversupply effect called the Kadenacy effect, observed in pulsating flows. The flow of air in the main inlet pipe is in fact in a vibratory state because of the alternating periods of opening and closing the inlet valve.

Consequently, by giving appropriate dimensions to the main pipe 6 and the chamber 11, it is possible to obtain that for a given speed of rotation of the motor, chosen in the scale of use, the opening of the inlet valve coincides with the existence of an overpressure at the level of the inlet orifice for the fluid in a vibratory state in the main pipe 6. There is thus obtained an excellent feed for the combustion chamber in the neighborhood of the considered speed and the feed is optimum for such operation (Kadenacy effect).

In the arrangement according to the invention adapted to a homogeneous feed which is represented in FIGURE 6 the conduit 29 connecting the top of the chamber 26 of the carburetor with the neck of the choke 8 will permit, as with the arrangement of FIGURE 1a, controlling the flow of motor fuel at 28' as a function of the air in the main pipe 6.

The calibrated orifice 31 provided in the construction of FIGURE 6 would have the effect already indicated above with respect to the arrangement shown in FIGURE 10:.

The butterfly valve 9 controlling the admission may be either directly fixed on the rod 44 supporting the cam track (FIGS. 1 and 1a) or coupled thereto through a lever and connecting rod system, as shown in FIGURE 7.

I claim:

1. In an automatic arrangement for the carburetor of an internal combustion motor, comprising a main inlet pipe provided with a main venturi, a rotating control element for controlling the volume of gas admitted into said pipe, said carburetor being provided with a jet, a needle cooperating with said jet, elastic means associated with said needle, a rod support, means for rotating said rod support about its axis as a function of the rotation of said control element, a cam track of nonuniform cross section in the axial direction having an internal bore through which said rod support passes, and adapted to allow said cam track to slide freely along said rod support, means for driving in rotation said cam track by said rod support, means controlling the sliding of said cam track as a function of the depression prevailing in said main inlet pipe, downstream from said rotating control element and a feeler cooperating with said needle applied against said cam track by said elastic means, the

provision of an auxiliary feed pipe, means for admitting air into said pipe, a channel extending into said auxiliary feed pipe for feeding motor fuel to the air admitted in said auxiliary pipe and control means for the flow of motor fuel feeding said auxiliary pipe, operating in response to the depression prevailing in said main inlet pipe at the level of the neck of said main venturi.

2. An arrangement according to claim 1, wherein said control means for the flow of motor fuel feeding said auxiliary pipe comprises an auxiliary chamber above said channel feeding motor fuel to said auxiliary pipe and a conduit connecting the upper portion ofsaid chamber with said main inlet pipe at the level of the neck of said main venturi.

3. An arrangement according to claim 2, wherein said auxiliary feed pipe includes an auxiliary butterfly valve for regulating the flow therethrough, an auxiliary venturi located upstream from said auxiliary butterfly valve and a calibrated orifice communicating with said auxiliary feed pipe, at the level of the neck of said auxiliary venturi and with the upper portion of said auxiliary chamber.

References Cited UNITED STATES PATENTS HARRY B. THORNTON, Primary Examiner. TIM R. MILES, Examiner.

Claims (1)

1. IN AN AUTOMATIC ARRANGEMENT FOR THE CARBURETOR OF AN INTERNAL COMBUSTION MOTOR, COMPRISING A MAIN INLET PIPE PROVIDED WITH A MAIN VENTURI, A ROTATING CONTROL ELEMENT FOR CONTROLLING THE VOLUME OF GAS ADMITTED INTO SAID PIPE, SAID CARBURETOR BEING PROVIDED WITH A JET, A NEEDLE COOPERATING WITH SAID JET, ELASTIC MEANS ASSOCIATED WITH SAID NEEDLE, A ROD SUPPORT, MEANS FOR ROTATING SAID ROD SUPPORT ABOUT ITS AXIS AS A FUNCTION OF THE ROTATION OF SAID CONTROL ELEMENT, A CAM TRACK OF NONUNIFORM CROSS SECTION IN THE AXIAL DIRECTION HAVING AN INTERNAL BORE THROUGH WHICH SAID ROD SUPPORT PASSES, AND ADAPTED TO ALLOW SAID CAM TRACK TO SLIDE FREELY ALONG SAID ROD SUPPORT, MEANS FOR DRIVING IN ROTATION SAID CAM TRACK BY SAID ROD SUPPORT, MEANS CONTROLLING THE SLIDING OF SAID CAM TRACK AS A FUNCTION OF THE DEPRESSION PREVAILING IN SAID MAIN INLET PIPE, DOWNSTREAM FROM SAID ROTATING CONTROL ELEMENT AND A FEELER COOPERATING WITH SAID NEEDLE APPLIED AGAINST SAID CAM TRACK BY SAID ELASTIC MEANS, THE

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