US3179388A

US3179388A - Carburettors comprising an auxiliary device for cold starting

Info

Publication number: US3179388A
Application number: US245479A
Authority: US
Inventors: Mennesson Andre Louis
Original assignee: Societe Industrielle de Brevets et dEtudes SIBE
Current assignee: Societe Industrielle de Brevets et dEtudes SIBE
Priority date: 1962-01-17
Filing date: 1962-12-18
Publication date: 1965-04-20
Anticipated expiration: 1982-04-20
Also published as: FR1319388A; DE1291938B; GB963126A

Description

April 1965 A. L. MENNESSON CARBURETTORS COMPRISING AN AUXILIARY DEVICE FOR COLD STARTING Filed Dec. 18, 1962 III/II ban 'llllllw/Ille 'IIIIIId;

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INVENTOR- AA/D/FE '4 00/6 mam/w sY g' United States Patent Ofifice 3,179,388 Patented Apr. 20, 1965 835,109 2 Claims. (Cl. 261-39) The present invention relates to carburettors for internal combustion engines and in particular for motor car engines, comprising, for the starting of said engines and the cold running thereof, an auxiliary device capable of increasing the fuel feed rate when the engine is cold, said device being operated by a bimetallic member subjected to the temperature of an element which is heated simultaneously with the engine.

As it is known, such an auxiliary device may consist of an eccentrically pivoted valve member disposed in the inlet conduit of the carburettor, upstream of the orifices through which fuel is supplied to this conduit, said valve member being urged in the opening direction by the suction of the engine, against the action of said bimetallic member. This last mentioned member generally consists of a spiral wound strip one end of which is fixed whereas the other end is free and acts upon the auxiliary valve member, the element to the temperature of which said strip is responsive being for instance heated by the exhaust gases of the engine, by the cooling water or by the lubricating oil of said engine, or being an electrical resistor energized at the same time as the ignition circuit of the engine.

A drawback of such an auxiliary device is that when the vehicle runs over small distances and is stopped for a substantial time between the running periods, the engine being then itself stopped, the bimetallic member does not reach a sufliciently high temperature at the end of these running periods for placing the auxiliary starting device out of action for a sumciently long time. Therefore, some minutes after stopping, the bimetallic member starts acting upon the starting device to restore it into operative position. It follows that, if the engine is started at this time, it makes use of the auxiliary starting device, at least partly, Whereas it is still warm enough not to require the operation thereof.

The object of the present invention is to obviate this drawback.

For this purpose, according to the present invention, the device comprises means capable of opposing to the displacement of the free end of the bimetallic member, in the vicinity of the position occupied by said end when said member is hot, a resistance greater in the direction corresponding to a cooling of this member than in the opposed direction.

A preferred embodiment of the invention will be hereinafter described with reference to the appended drawings, given merely by way of example, and in which:

FIG. 1 is an elevational view, partly in section, of a carburettor provided with a device according to the present invention for controlling the fuel rate in. the fuel and air mixture fed to an internal combustion engine, the carburettor being shown in the cold running position;

FIG. 2 is a half section on the line II-II of FIG. 1;

FIGS. 3, 4 and 5 are views, similar to a portion of FIG. 1, and showing the elements thereof in the respective posi tions they occupy according to three different conditions of operation;

FIG. 6 shows a curve illustrating the operation of a device according to FIGS. 1-5, the temperature being plotted in abscissas and the angular positions of the free end of a bimetallic strip in ordinates.

The general construction of the carburettor proper may be of any suitable kind. For instance, as shown, it comprises an air intake 1, an intake conduit 2 provided with a venturi 3 and with a throttle valve 4, a fuel feed conduit 5 provided with orifices 6 opening at the level of the venturi throat, the throttle valve 4 being-intended to be operated by the driver.

Concerning the starting device, it comprises an eccentrically pivoted valve 7 placed in the air intake 1 upstream of venturi 3 and rigid with a spindle 8 journalled in the wall of the air intake conduit. At one of the ends of this spindle 8 there is fixed a lever 9 carrying a finger 10 engaged in the hook shaped free end 11a of a spiral wound bimetallic strip 11 the inner end 11b of which is fixed on a finger 12. Strip 11 is located in a casing 13, carrying finger 12 and where the temperature is fixed by a fluid (air or water) circulating in the vicinity of strip 11. An electric resistor may also be placed in casing 13 close to strip 11. Anyway the fluid or the resistor is at a temperature varying in the same manner as that of the internal combustion engine.

When spiral wound strip 11 is cold (FIG. 1) its end 11a is located on line X (corresponding to the angle A of FIG. 6) and valve member 7 is in the closed position. When spiral strip 11 is sufficiently heated (FIG. 3), its end 11a is located in the vicinity of line X (corresponding to the angle A of FIG. 6) and valve 7 is fully open, the starting device being then wholly out of action. When the end 11a of strip 11 moves beyond line X for instance as far as line X (FIG. 3) corresponding to angle A (FIG. 6), auxiliary valve 7 is stopped by an abutment (not shown).

According to the present invention the device comprises means capable of opposing, to the movement of the free end 11a of spiral wound strip 11, in the vicinity of the position occupied by said free end 11a when strip 11 is hot, a resistance greater in the direction corresponding to the cooling of this strip (anti-clockwise direction) than in the opposed, i.e. the clockwise, direction. Advantageously, as shown, said means consist of a lever 14 pivoting about an axis 15 parallel to spindle 8, this lever being urged by a spring 16 and carrying a wedged-shaped, or nose, portion 17, the two opposed faces of which are adapted to cooperate alternately with the end 11a of strip 11.

l In the embodiment of the invention illustrated by the drawings, when spiral strip 11 is heated, the end 11a of said strip comes to slide along the left hand face of nose 17 until it escapes therefrom and passes on the other side thereof, and, when this strip 11 is cooling down, said strip end 11a, after coming into contact with the right hand face of said nose portion 17 of lever 14, causes said lever to pivot about its axis 15, this action being resiliently opposed by that of spring 16.

Lever 14 cooperates with a fixed abutment 18, on one side, and, on the other side, with a push piece 19 slidable against the action of spring 16, adjustable by means of a screw 20.

This system works as follows:

When the engine is started the elements of the device occupy the position of FIG. 1. In this position spiral wound strip 11 keeps, as far as possible, valve 7 closed against the action of the suction created by the engine. But, as bimetallic strip 11 is getting warm, it tends to wind up audits end 11a is displaced in the clockwise direction. After a given time said end 11a comes into contact'with the left hand face of the portion17 of lever 14 which cannot move since it is applied against its abutment 18 and said strip end slides along this face until it is located along line X corresponding to the vertical position of valve member 7. But spiral wound strip 11 is free to wind up further inresponse to the rise of temperature,

its end lla moving past the end of nose 17 and coming into the position shown by line X in FIG. 3.

If at this time the engine is stopped, spiral strip 11, which is no longer being heated, should not come back too quickly into the position of FIG. 1 or at least into a position ranging between X, and X which would corre spond to a partial closing of valve member 7 and would permit the starting device to be again operated as soon as the engine is once more started.

'Lever 14 then acts in the following manner (FIG. 4). When spiral strip 111 is cooling down, it unwinds, that is to say its free end 11a moves in the anti-clockwise direction. Thisend 11a then comes, at a given time, to bear upon the right hand face of the nose 17 of lever 14 (FIG. 4), which face is perpendicular to the direction of movement of the strip end 11a. Therefore,'in said position of FIG. 4, lever 14 does not exert any reaction tending to cause the end 11a of strip 11 to pass from the right hand side to the left hand side of nose 17. It is therefore necessary for strip 11 to pivot lever 14, against the action of spring 16, to bring said lever 14 into a position (such as that of FIG. 5) where the end 11a of strip 11 can slide along the right hand face of nose 17, to move beyond the end of said nose and to come upon the left hand side thereof. This is possible only if strip 11 exerts a sufficient effort, that is to say if the temperature has reached, when decreased, ,a value lower than that for which, during the preceding temperature rise, the end lla of strip 11 has moved beyond the position indicated by line X To sum up, it will be seen that when, due to a rise of the temperature, spiral strip 11 is wound up, i.e. when its end Illa moves in the clockwise direction,ait reaches position X for a given temperature. But if it has moved beyond this position and the temperature decreases,thus tending to move said strip end 11a in the'anti-clockwise direction, it can move beyond position X only for a temperature much lower than that for which it exceeded this position when rotating in the clockwise direction. s

The curve of FIG. 6 illustrates the operation of this device. In said figure the temperature T in centigrade degrees is plotted in abscissas and the angular position of the end 11a of bimetallic strip 1 1 is plotted in ordinates. ,The curve in solid lines corresponds to increasing values of temperature T.

If it is supposed that the position X (angle equal to zero as designated by A corresponds to a temperature of C. and the position X (angle A to a temperature of +45 C., a small horizontal curve portion is noted after'this temperature, corresponding to the necessity forthe end 11a of strip 11 to reduce its radius so as to be able to move beyond the apex of nose 17. Then the angle increases asa function of the temperature for instance up to a value A If then the temperature begins to decrease, the curve is no longer the solid lines curve, but the curve in dotted lines. It Will be seen that for angle A (line X in FIG. 3), the end 11a of strip 11 comes back into contact with lever 14. At this time'a reduction of the temperature does not immediately reduce angle A. It is only when spring 16 is sufficiently compressed, that suddenly the end 11a of strip 11 moves beyond nose 17 (FIG. 5), which corresponds to the vertical portion of the curve in dotted lines of FIG. 6.

In the example illustrated by FIG. 6, during the heating up period valve member 7 is in the vertical position, the starting device being then out of action for a temperature of strip 11 of 45 C. On the contrary, during the cooling down period strip 11 can act'upon valve '7 to move it into the closed position only for a temperature of C.

When the strength of spring 16 isadjusted by means of screw 20, the cooling curve portion is modified for instance from'the shape shown in dotted lines to that s 11a of strip 11 has released lever 14, this lever comes back into its initial position under the action of spring 16 and it is ready to act once more if the spiral wound strip 11 is once more heated. t 7

Of course the bimetallic strip instead of being spiral wound might have the shape of a helix or any other curve. a

In a generalmanner, while the above description discloses what is deemed to be a practical and efficient embodiment'of the invention, said invention is not limited thereto as there might be changes made in the arrangement, disposition and form of the parts without departing from the principle of the invention as comprehended within the scope of the appended claims.

What I claim is:

1. In a carburettor for an internal combustion engine, an auxiliary devices of the type described which comprises, in combination, a frame, a choke valve movably carried by said frame for varying the fuel rate of the fuel and air mixture supplied by said car burettor, said choke valve having a closed position where the fuel rate is maximum and an open positionswhere the fuel rate is lower, a bimetallic spiral strip responsive to variations of said internal combustion engine temperature, said bimetallic spiral strip being fixed at its inner end to said frame about an axis, the outer end of said bimetallic strip being movable with respect to said frame between a cold state position and a hot state position along a given path of travel,

said bimetallic strip outer end being, operatively connected with said choke valve for gradually opening said choke valve from its closed position when said temperature corresponds to the engine being cold to its open position when said temperature has raised to a given value, a lever pivotedto said frame about an axis parallel to said first mentioned axis, said lever having a wedgeshaped portion adapted to cooperate with said strip outer end and located between the cold state position and the hot state position of said bimetallic strip outer end, said wedge-shaped lever portion having a first'face turned toward said bimetallic strip cold state position, and a second face turned toward said bimetallicstrip hot state position, said strip being so arranged that its outer end is out of contact with-said lever when the engine is cold and is applied against said first face of said lever wedgeshaped portion when the engine temperature has raised to said given value so that said strip outer end can slide along said first face and beyond it to said second face of said wedge-shaped portion when the engine temperature rises above said given value, said second face of said lever wedge-shaped portion being at least substantially perpendicular to the path of travel of said strip outer end for said given position of said lever, and spring means carried by said frame adapted resiliently to urge said lever in the direction opposed to that in which it is pushed by said strip outer end moving from its hot state position toward its cold state position, so as yieldingly to oppose the rotation of said lever produced by the push of said strip outer end on said second face of said lever wedge-shaped portion during a lowering of the engine temperature.

2. In a carburettor for an internal combustion engine, an auxiliary device of the type described which comprises, in combination, a frame, a choke valve movably carried by said frame for varying the fuel rate of the fuel and air mixture supplied by said carburettor, said choke valve :having a closed position where the fuel rate is maximum and an open position where the fuel rate is lower, a bimetallic spiral strip responsive to variations of said internal combustion engine temperature, said bi metallic spiral strip being fixed at its inner end to said frame about an axis, the outer end of said bimetallic strip being movable with respect to said frame between a cold state position and a hot state position along a given path oftravel, said bimetallic strip outer end being operatively connected with said choke valve for gradually opening said choke valve from its closed position when said temperature corresponds tothe engine being cold to its open position when said temperature has raised to a given value, a lever pivoted to said frame about an axis parallel to said first mentioned axis, said lever having a wedge-shaped portion adapted to cooperate with said strip outer end and located between the cold state position and the hot state position of said bimetallic strip outer end, said wedge-shaped lever portion having a first face turned toward said bimetallic strip cold state position, and a second face turned toward said bimetallic strip hot state position, spring means carried by said frame adapted resiliently to urge said lever in the direction opposed to that in which it is pushed by said strip outer end moving fromits hot state position toward its cold state position, and an abutment fixed with respect to said frame and adapted to cooperate with said lever to limit its displacement by said spring means to a position such that said strip outer end is out of contact with said lever when the engine is cold and is applied against said first face of said lever wedge-shaped portion when the engine temperature has reached said given value, said first face being oblique to the path of travel of said strip outer end so that said strip outer end can slide along said first face and beyond it to said second face of said wedgeshaped portion when the engine temperature rises above said given value, said second face of said lever wedgeshaped portion being at least substantially perpendicular to the path of travel of said strip outer end for said given position of said lever, and said spring means being arranged yieldingly to oppose the rotation of said lever produced by the push of said strip outer end on said second face of said lever wedge-shaped portion during a lowering of the engine temperature.

References Cited by the Examiner UNITED STATES PATENTS 627,390 6/99 Cash. 1,715,327 5/29 Ivanhoif 236-48 X 2,011,546 8/35 Waltenberg 23648 2,834,586 5/58 Szwargulski 26139 2,946,577 7/60 Dennison et al 261-39 HARRY B. THORNTON, Primary Examiner.

HERBERT L. MARTIN, Examiner.

Claims

1. IN A CARBURETTOR FOR AN INTERNAL COMBUSTION ENGINE, AN AUXILIARY DEVICES OF THE TYPE DESCRIBED WHICH COMPRISES, IN COMBINATION, A FRAME, A CHOKE VALVE MOVABLY CARRIED BY SAID FRAME FOR VARYING THE FUEL RATE OF THE FUEL AND AIR MIXTURE SUPPLIED BY SAID CARBURETTOR, SAID CHOKE VALVE HAVING A CLOSED POSITION WHERE THE FUEL RATE IS LOWER, MUM AND AN OPEN POSITION WHERE THE FUEL RATE IS LOWER, A BIMETALLIC SPIRAL STRIP RESPONSIVE TO VARIATIONS OF SAID INTERNAL COMBUSTION ENGINE TEMPERATURE, SAID BIMETALLIC SPIRAL STRIP BEING FIXED AT ITS INNER END TO SAID FRAME ABOUT AN AXIS, THE OUTER END OF SAID BIMETALLIC STRIP BEING MOVABLE WITH RESPECT TO SAID FRAME BETWEEN A COLD STATE POSITION AND A HOT STATE POSITION ALONG A GIVEN PATH OF TRAVEL, SAID BIMETALLIC STRIP OUTER END BEING OPERATIVELY CONNECTED WITH SAID CHOKE VALVE FOR GRADUALLY OPENING SAID CHOKE VALVE FROM ITS CLOSED POSITION WHEN SAID TEMPERATURE CORRESPONDS TO THE ENGINE BEING COLD TO ITS OPEN POSITION WHEN SAID TEMPERATURE HAS RAISED TO A GIVEN VALUE, A LEVER PIVOTED TO SAID FRAME ABOUT AN AXIS PARALLEL TO SAID FIRST MENTIONED AXIS, SAID LEVER HAVING A WEDGESHAPED PORTION ADAPTED TO COOPERATE WITH SAID STRIP OUTER END AND LOCATED BETWEEN THE COLD STAGE POSITION AND THE HOT STATE POSITION OF SAID BIMETALLIC STRIP OUTER END, SAID WEDGE-SHAPED LEVER PORTION HAVING A FIRST FACE TURNED TOWARD SAID BIMETALLIC STRIP COLD STATE POSITION, AND A SECOND FACE TURNED TOWARD SAID BIMETALLIC STRIP HOT STATE POSITION, SAID STRIP BEING SO ARRANGED THAT ITS OUTER END IS OUT OF CONTACT WITH SAID LEVER WHEN THE ENGINE IS COLD AND IS APPLIED AGAINST SAID FIRST FACE OF SAID LEVER WEDGESHAPED PORTION WHEN THE ENGINE TEMPERATURE HAS RAISED TO SAID GIVEN VALUE SO THAT SAID STRIP OUTER END CAN SLIDE ALONG SAID FIRST FACE AND BEYOND IT TO SAID SECOND FACE OF SAID WEDGE-SHAPED PORTION WHEN THE ENGINE TEMPERATURE RISES ABOVE SAID GIVEN VALUE, SAID SECOND FACE OF SAID LEVER WEDGE-SHAPED PORTION BEING AT LEAST SUBSTANTIALLY PERPENDICULAR TO THE PATH OF TRAVEL OF SAID STRIP OUTER END FOR SAID GIVEN POSITION OF SAID LEVER, AND SPRING MEANS CARRIED BY SAID FRAME ADAPTED RESILIENTLY TO URGE SAID LEVER IN THE DIRECTION OPPOSED TO THAT IN WHICH IT IS PUSHED BY SAID STRIP OUTER END MOVING FROM ITS HOT STATE POSITION TOWARD ITS COLD STATE POSITION, SO AS YIELDINGLY TO OPPOSE THE ROTATION OF SAID LEVER PRODUCED BY THE PUSH OF SAID STRIP OUTER END ON SAID SECOND FACE OF SAID LEVER WEDGE-SHAPED PORTION DURING A LOWERING OF THE ENGINE TEMPERATURE.