US2533602A

US2533602A - Carbureting device

Info

Publication number: US2533602A
Application number: US650517A
Authority: US
Inventors: Mennesson Marcel Louis
Original assignee: Solex SA
Current assignee: Solex SA
Priority date: 1945-02-08
Filing date: 1946-02-27
Publication date: 1950-12-12
Anticipated expiration: 1967-12-12

Description

Dec. 12, 1950 M. L. MENNESSON CARBURETING DEVICE Filed Feb. 27, 1946 A VII/14,1!!! Ill 7 INVENTOR MA RCEL Louis MENNESSON TOR NEY Patented Dec. 12, 1950 CARBURETING DEVICE Marcel Louis Mennesson,

Neuilly-sur-Seine,

France, assignor to Societe Solex, a society of the Republic of France Application February 2'7, 1946, Serial No. 650,517 In France February 8, 1945 Section 1, Public Law 690, August 8, 1946 Patent expires February 8, 1965 2 Claims.

The present invention relates to carburetting devices including an auxiliary carburetter for facilitating the starting from cold of internal:

combustion. engines, said auxiliary carburetter being of the kind of those described in French Patents No. 700,188 and 751.064, filed by Socit Anonyme Solex. Such auxiliary carburetters essentially include a well communicating through a calibrated orifice with the constant level chamber below the fuel level, and fed with air at its upper part, the fuel mixture thus obtained being mixed with air, and the whole being fed, through a passage controlled by a cock, to the engine intake pipe on the downstream side of its throttle valve.

The chief object of my invention is to provide a device of this kind which is better adapted to meet the requirements of practice than those made up to this time, in particular concerning the feed of air to the air intakes of the auxiliary carburetter and the fluidtightness of the cock that serves to bring the auxiliary carburetter into or out of action and to adjust the section of the passage through which the fuel mixture is fed to the engine intake.

According to a feature of the present invention, the air intakes in question and in particular the upper end of the well are connected, not with the atmosphere but with the. space of the constant level chamber above the fuel, said space being itself connected, through an orifice of large section, with the main air inlet-generally fitted with a purifier or filter-of the main carburetter, so that the air intakes of the auxiliary carburetter are fed through the air intake of the main carburetter and any slight depression as may be produced in the well of the auxiliary carburetter, when the latter is brought into play, remains practically without influence on the pressure existing in the constant level chamber.

According to another feature of the present invention, there is provided, between the parts of the channel for the feed of the fuel mixture from the auxiliary carburetter that are respectively located on the upstream side and the downstream side of the above mentioned cock, a chamber in communication either with the atmosphere, or with the air intake of the main carburetter or again with the constant level chamber above the normal fuel level therein, in order to prevent the depression, existing in the downstream part, from being transmitted to the upstream part due to a lack of fluidtightness of said cock.

Fig. 1 shows, in diagrammatic axial section, a

carburetting device made according to the invention; Fig. 2 shows, in a similar way, a portion of the same device, but with parts thereof occupying another position;

Fig. 3 is a view, similar to Fig. 2, showing a modification.

The main carburetter is constituted in any suitable manner, in particular as usual. Fig. 1

' shows, by way of example, only some essential elements of an inverted type carburetter, i. e. a body I, an air intake 2 (generally provided with a purifier or filter), a venturi 3, a jet device 4 (shown in external view), a throttle valve or butterfly valve 5, and a constant level chamber 6 with its float I.

Concerning the auxiliary carburetter it is essentially constituted, as indicated in French Patents No. 700,188 and 738,525 filed by Socit Anonyme Solex. In the example illustrated by the drawings, it includes a well 9 fed with fuel, at its lower part, through a calibrated orifice l0 opening into the constant level chamber 6 below the fuel level therein. A conduit ll starting from a point of well 9 located at a given distance below the fuel level leads,,through a channel I2, to a distributing device including a chamber l3 and a plate or disc M, of generally circular shape, adapted to be rotated by means of a spindle l5 and an eternal control member i6. Said plate is applied on its seat, constituted for instance by a plane portion of the body I of the carburetter, by a spring l1 so as to form a fluidtight partition between channel l2 and chamber l3 when the cock is closed (Fig. 2).

When the cock is open (Fig. 1) for bringing the auxiliary carburetter into action, an orifice l8 provided in plate I4, is in registry with the opening of channel [2 and permits the contents thereof to pass into chamber 13. At the same time another orifice IQ of plate I4 comes opposite a passage 20 opening into the intake pipe of the engine, on the downstream side of throttle valve 5, and therefore in direct communication with the engine. Chamber I3 is permanently connected, through calibrated orifice 22, with a conduit 2| which communicates at 23 with the air intake 2 of the main carburetter. Under these conditions the depression from the engine is transmitted to chamber I 3 through passage 20 and sucks in, on the one hand the air supplied through conduit 2|, and calibrated orifice 22 and, on the other hand, the fuel mixture delivered through channel l2 and conduit II from well 9.

In the above mentioned prior patents, the upper part of-well 9 was connected directly with the atmosphere or with the air intake of the main carburetter.

According to the present invention, the upper part of the well communicates, at 24, with the constant level chamber 6above the normal level of the fuel contained in this chamber-and, consequently, with the air intake of the main carburetter through orifice 8.

As the transverse section of well 9 is large in comparison with that of conduit ll, calibrated orifice I is subjected but to a small portion of the depression that exists in said conduit I I, and its output is substantially constant. It follows that the fuel mixture becomes leaner and leaner as the speed of the engine increases. However, in order to have an operation that is quite correct, the free surfaces of the liquid, in well 9 and in the constant level chamber must be exactly at th same pressure, otherwise a slight difference of pressure would cause the fuel to rise or to drop in well 9 thus producing pcrturbances that are often very serious.

The only way to obtain this result is to cause the upper part of well 9 to open into the constant level chamber itself, this chamber being in communication with the main air intake 2 through an orifice 8 of sufficiently large size. As a matter of fact, if orifice 8 is too small, conduit II creates a. slight depression in constant level chamber 6, which has for its efiect to cause a drop of level in the main jet system 4 and to make it difficult for gasoline to spout out from this system when butterfly valve 5 is gradually opened for increasing the power of the engine. It is therefore important that the depression existing in conduit II when starting should produce no depression in constant level chamber 6.

It is therefore necessary to give orifice 8 a sumciently large section. On the other hand conduit II has a portion thereof located at a sufiiciently high level for avoiding a constant flow of fuel toward plate I.

When the auxiliary carburetter is started into operation, there might take place a siphoning of the fuel through conduit II, channel I2 and orifice i8 when the latter is open or even through an eventual leak between plate It and its seat if orifice I8 is not opposite the channel I2. In order to avoid such a siphoning, a hole 25 is provided at the top point of conduit II. On the other hand, when the auxiliary carburetter is out of action, orifice I9 is no longer opposite passage 28 and orifice I8 is no longer opposite the opening of channel 20.

It was proposed, in the prior patents above mentioned, to providewhen the auxiliary carburetter is out of action-a second orifice, analogous to that designated by I3. for causing atmospheric pressure to act in conduit I I. In the case of the device that constitutes the object of the present invention, such a hole would connect channel I2 with chamber I3 and, consequently, with the main air intake of the car- Now,

channel I2 and chamber I3. But it may happen, due to a lack of fluid tightness, that the depression from the engine intake pipe is transmitted through passage 20 to channel I2 by passing between plate Id and its seat, which would have for its effect to suck out fuel from well 9, this fuel then passing direcly into the suction pipe of the engine.

This is remedied by surrounding the outlet of channel I2 by a groove 26' communicating, for instance, with the outside. With such an arrangement, a slight depression tending to reach channel l2 through the interval that may exist between plate M and its seat would first meet with this groove 26 and the only inconvenience that might result therefrom would be that the engine would suck in a small amount of air through the leak thus formed.

However, there may also exist a slight lack of fluidtightness between groove 26 and channel I2 due to a defective contact between plate It and its seat and, in these conditions, as constant level chamber 6 may be at a pressure lower than atmospheric pressure, air from the outside would enter conduit II through channel I2 and groove 26 and bubble in well 8, thus causing perturba-.

tions therein. It is therefore of interest to place groove 26 in communication through a conduit 27 with the part of constant level chamber 6 above the normal fuel level therein. In this way no diiTerence of pressure can occur, when the auxiliary carburettor is out of action (Fig. 2), between channel I2 and groove 25, the latter remaining quite as efficient for compensating the eliects of a certain suction transmitted from passage 20.

Another solution, shown by Fig. 3, consists in placing groove 26 in communication, through passage 28, with chamber I3. When the auxiliary carburetter is out of action (Fig. 3) passage 28 communicates directly with the carburetter air intake through chamber l3, calibrated orifice 5 difference of pressure may exist between conduits II and I2 on the one hand, which are at the pressure of constant level chamber 6, and groove 26 on the other hand which is at the pressure existing in the carburettor air intake, at the inlet 23 of conduit 2 I.

This slight difierence of pressure might produce a circulation of fuel through conduits 2|, I2 and II, but this can be remedied, as in the preceding case, by having recourse to a hole 25 (Fig. 1) which permits an inflow of air into conduits II and I2 preventing fuel from being sucked up to the top point of conduit II from which it could pass into channel I2. However the size of hole 25 is chosen such that it does not interfere with the suction of the fuel when plate I4 occupies a position for which the auxiliary carburetter is in action (Fig. 2), that is to say when the maximum depression exists in conduit II.

Of course, the air that feeds calibrated orifice 22 might also be taken from constant level chamber 6 but as this orifice is, on the one hand and in general, of rather important dimension and, on the other hand, subjected to a strong suction, this arrangement would lead to an orifice 8 of considerable section. It is therefore preferable to have conduit 2i opening, at 23, into the main air intake of the carburetter and not into the constant level chamber.

In this carburation device, including a starting auxiliary carburettor, all the possible air intakes finally lead to the main air intake of the carburetter and are, consequently, fed with air filtered by the main filter of the carburetter, if such a filter exists, without having to fear that the feeds of these difierent air intakes, including that of the constant level chamber, give rise, during the working of the engine, to local pressure differences which might be the cause of disturbances in the working of the auxiliary carburetter or even in that of the constant level chamber.

In a general manner, while I have, in the above description, disclosed what I deem to be practical and efliclent embodiments of the present invention, it should be well understood that I do not wish to be limited thereto as there might be changes made in the arrangement, disposition and form of the parts-without departing from the principle of the present invention as a main carburetter including an air intake, a

constant level chamber communicating with said air intake through a large section passage, an induction pipe to be connected with said engine, and a throttle valve in said pipe, and an auxiliary carburetter for starting the engine from cold including a well provided with a calibrated orifice opening into said constant level chamber below the fuel level therein and with only one air inlet in direct communication exclusively with the space of said constant level chamber above the fuel level therein, a chamber located below said first mentioned chamber, a conduit starting from said well at a point thereof located below the fuel level in said constant level chamber, passing above said level and opening into one wall of said second mentioned chamber, a conduit starting from said induction pipe on the downstream side of said throttle valve and opening into said wall of the last mentioned chamber, a valve member slidable along said wall adapted either to connect both of said conduits with said last mentioned chamber or to cut off both of them therefrom, a conduit provided with a calibrated orifice for connecting said last mentioned chamber with said air intake, said wall of said last mentioned chamber being provided with an annular groove surrounding the opening of the first mentioned conduit into said wall, and means for connecting said groove with said second mentioned chamber.

2. A carburation device for an internal com bustion engine which comprises, in combination,

a main carburetter including an air intake, a

constant level chamber communicating with said air intake through a large section passage, an induction pipe to be connected with said engine, and a throttle valve in said pipe, and an auxiliary carburetter for starting the engine from cold including a well provided with a calibrated orifice opening into said constant level chamber below the fuel level therein and with only one air inlet in direct communication exclusively with the space of said constant level chamber above the fuel level therein, a chamber located below said first mentioned chamber, a conduit starting from said well at a point thereof located below the fuel level in said constant level chamber, passing above said level and opening into one wall of said second mentioned chamber, the upper portion of said conduit being provided with an orifice of small section connecting it with the space of said constant level chamber located above the fuel level therein, a conduit starting from said induction pipe on the downstream side of said throttle valve and opening into said wall of the last mentioned chamber, a valve member slidable along said wall adapted either to connect both of said conduits with said last mentioned chamber or to cut off both of them therefrom, a conduit provided with a calibrated orifice for connecting said last mentioned chamber with said air intake, said well of said last mentioned chamber being provided with an annular groove surrounding the opening of the first mentioned conduit into said wall, and means for connecting said groove with said second mentioned chamber.

MARCEL LOUIS MENNESSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS France June 12, 1933