EP0165679A1

EP0165679A1 - A system for automatically adjusting the diffuser and gasoline passage sections of carburetors

Info

Publication number: EP0165679A1
Application number: EP85303033A
Authority: EP
Inventors: Angel Gomez Romero
Original assignee: Individual
Current assignee: Individual
Priority date: 1984-04-30
Filing date: 1985-04-29
Publication date: 1985-12-27
Also published as: BR8502132A

Abstract

A system for automatically adjusting the diffuser and gasoline passage sections of carburetors. During acceleration, the passage section of the diffuser (5) is increased gradually simultaneously with the opening of the throttle valve, and a needle valve (3) for the inlet of gasoline to the nozzle is opened. A gasoline overfeed valve (43) is activated to initiate acceleration, which activation is interrupted at successive positions of the accelerator. Said overfeed valve is also activated when starting a cold engine by pulling the starter, closing its throttle valve and partially opening the acceleration valve, with the consequent increase in the diffuser and gasoline passage sections.

Description

The present invention refers to a system for automatically adjusting the diffuser and gasoline passage sections of carburetors.
According to the present invention there is provided a system for automatically adjusting diffuser and gasoline passage sections of carburetors, characterised in that during acceleration, simultaneously with the opening of the throttle valve, a diffuser section is increased gradually and a needle valve for the inlet of gasoline to the nozzle is opened; a gasoline overfeed valve is activated to initiate acceleration, which activation is interrupted at successive positions of the accelerator, said overfeed valve also being activated when starting a cold engine by pulling the starter, closing its throttle valve and partially opening the acceleration valve, with the consequent increase in the diffuser and gasoline passage sections.
A system of the invention has a lesser fuel consumption, a higher power and an optimum performance, achieving an air-gasoline mixture for optimum combustion thereof at all times.
The carburetor of the invention can be installed in any type of vehicle, achieving, due to the perfect combustion of the mixture, a very low atmospheric contaminating index.
Preferably, upon acceleration the gasoline overfeed valve is activated, its activation being interrupted at successive positions of the accelerator whilst the diffuser and gasoline passage sections are simultaneously increased.
When pulling the starter at the time of starting a cold engine, its corresponding throttle valve is closed and, by means of a plurality of levers joined to the axis of rotation thereof, the partial opening of the acceleration valve controlling the gasoline overfeed valve is produced, whilst the diffuser and gasoline passage sections, ideal for the starting, are obtained.
To vary the diffuser section, the carburetor is comprised of a body including a separate portion positioned in a hollow thereof and retained by an upper cover fixed to the body by screws. This separate portion occupying the area of the diffuser is divided into two complementary parts, one of which is maintained fixed whilst the other can move in a horizontal plane, this movement being achieved with the turn of the shaft of the acceleration valve.
The shaft of the acceleration valve is provided with an upgrade cam, placed in a transversal plane to said shaft, which, when turning, presses the projection of a rod fixed to the movable part of the diffuser. Upon acceleration, the rod is pulled, increasing the diffuser section which is reduced when decelerating, due to an antagonistic spring axially coupled therein.
To vary the gasoline passage section, the needle valve is displaceable to close, to a greater or lesser degree, the corresponding opening. This displacement of the needle valve takes place through a normal rocker arm secured to the free end of the throttle valve shaft which pulls the end of the lever pivoted in the carburetor body and which contacts the end of the needle.
The rocker arm secured to the throttle valve shaft acts, in turn, on the gasoline overfeed valve through a rod, whereby fuel is injected in the diffuser, when acceleration is initiated. This overfeed pumping is also produced when the starter is pulled, since the shaft of its throttle valve is joined to an assembly of levers acting on the upgrade cam, causing a partial acceleration of the engine.
In an embodiment of the invention, the diffuser section is automatically adjusted through an articulated series of rods from the shaft of the acceleration valve until the free end of the last lever, pivoted in a support fixed to the carbureter body, presses the front end of a shaft secured to the movable part of the diffuser, likewise aided by a recovery spring.
The simultaneous variation of the gasoline passage section in the needle valve is also preferably achieved by an eccentric anchorage to the inner end of the shaft of the acceleration valve, of a bent lever, the free end of which incorporates the screw for adjusting the initial gasoline passage, this adjusting screw butting with the needle provided with the recovery spring and with a cylindrical guide extension in an axial hole of the needle, acting as a support for said bent lever.
For the gasoline overfeed to simultaneously take place during acceleration of the engine, said overfeed valve is, in an embodiment, a diaphragm valve, the diaphragm pusher being pressed by the end of a lever pivoting at its central zone in a point of the carburetor body, this lever being joined to a prolongation of one of the articulated levers controlling the displacement of the movable part of the diffuser.
This gasoline overfeed diaphragm valve can also be activated by the starter, by a cam profile of the anchorage lever of the starter cable which leads directly to the profile of another cam secured to the shaft of the acceleration valve.
Embodiments of the invention are hereinafter described, by way of example, with reference to the accompanying drawings, in which:-

Figure 1 is a plan view of a carbutetor provided with a system of the invention for automatically adjusting the diffuser and gasoline passage sections,
Figure 2 is a longitudinal elevational view of the carburetor of Fioure 1,
Figure 3 is a plan view of the carburetor body corresponding to the area occupied by the diffuser,
Figure 4 is a section on line D-D of Figure 1,
Figure 5 is an elevational view from the left hand side of Figure I,
Figure 6 is a section on line C-C of Figure 1,
Figure 7 is an elevational view, from the right hand side of Figure 1, corresponding to the position of the idle accelerator,
Figure 8 is an elevational view, similar to that of Figure 7, corresponding to an initial acceleration position, when the starter is pulled, from which some auxiliary details have been removed for a better understanding,
Figure 9 is a section on line B-B of Figure 1,
Figure 10 is a section on line A-A of Figure 1,
Figure 11 is a side elevational view of a further embodiment of a carburetor of the invention,
Figure 12 is a side elevational view of the embodiment of Figure 11,
Figure 13 is a partly sectional elevational view, along a vertical plane passing through the shaft of the diffuser, corresponding to Figures 11 and 12,
Figures 14 and 15 are plan views of the carburetor of Figures 11 to 13, without the upper cover and with it, respectively, and
Figure 16 is an elevational view of the face opposite to that of Figure 11.

Referring to the drawings, it can be seen that the carburetor of the invention has a left part, generally referenced 1, including the fuel nozzle maintained at a constant level by the float 2 joined to the needle valve 3, so that it can reach the tank 4, the outlets of which are disposed in the diffuser 5 placed at the right part 6 of the carburetor, as illustrated in Figures 1 and 2.
The diffuser section of the invention is varied since the carburetor body corresponding to the right part 6 is determined by a base 7 and an upper cover 8. The base 7 of the body is provided with a prismatic hollow 9, as illustrated in Figures 3 and 4, in which a separate portion forming the diffuser 5 itself is placed.
The separate portion forming the diffuser 5 is comprised of two parts 10 and 11 complementary of the outlet. In accordance with the embodiment of Figure 3, the part 11 of the diffuser 5 fits in and is fixed in the hollow 9 of the carburetor body 7, whilst the complementary part 10 can adopt a relative sliding position with respect to the former, between twolimits defined by the contact of its left side face 12 with the corresponding face 13 of the hollow 9, which corresponds to the smallest section of the diffuser 5, and another to the largest section thereof, when the right face 14 of the movable part 10 of the diffuser contacts the face 15 of the hollow 9; which sliding takes place on close fitting support and guide surfaces defined by the base of the hollow 9, the side 16 thereof, the-bottom surface of the cover 8 of the carburetor, and the contacting planes 17 and 18 between both parts 10 and 11.
The movable part 11 of the diffuser 5 slides in its plane since it is joined to a rod 19 guided in a hole 20 made in the-base 7 of the carburetor body, and which is maintained in the position of minimum passage section of the diffuser, by an axial spring 21 retained by a threaded cap 22. The rod 19 is provided with a groove 23 at its lower zone in which is comprised the end zone of a cam 24 secured to the shaft 25 of the acceleration valve 26. This valve 26 is illustrated with dotted lines in Figure 2.
The cam 24 has a circular section and presents an upgraded front 27, acting as the cam itself displacing, when turning, the rod 19. Upon acceleration, the turn of the cam 24 causes the displacement of the rod 19, overcoming the action of the spring 21, so that the passage section of the diffuser 5 is increased; upon deceleration, the ramp 27 concentric to the axis of rotation 25 permits the rod 19 to be displaced in favour of the spring 21, until the minimum passage section of the diffuser 5 is achieved.
The two independent parts 10 and 11 forming the diffuser 5 are interchangeable, depending on the engine displacement, since the outer geometry thereof, corresponding to the hollow 9 of the base 7 of the carburetor body, is conserved.
To vary the gasoline passage section. in the needle valve 3, in accordance with the engine acceleration, a proportioned rocker arm 28 is secured to the free end of the shaft 25 of the acceleration valve which, since it is provided with a lower groove 29, as illustrated in Figure 10, pulls when turning a lug 30-protruding from the end of a lever 31 which pushes the needle 32 of the needle valve 3, whereby this closes the access to the corresponding opening 33, to a greater or lesser extent.
Said lever 31 is pivoted on a pin 34 fixed to the projection 35 of the part 1 of the carburetor body. This hinge pin 34 passes through the arm 36 of this lever 31, so that the free end of the needle 32 contacts the said lever 31.
When the accelerator is depressed, its cable, not represented in the drawings, fixed to the radial lever 37 of the shaft 25 of the acceleration valve, causes the rocker arm 28 to turn, so that the needle 32 is separated from the opening 33, due to the spring 38 which simultaneously liberates its tension and which is wound on its free end.
The initial section for the passage of gasoline through the opening 33, depending on the position of the needle 32 corresponding to the idle position, is fixed by the adjusting screw 39 and nut 40, threaded to the hinged lever 31 and in an axial direction to the needle 32. The opening 33 is firstly selected in accordance with the engine displacement.
The rocker arm 28 secured to the shaft 25 of the engine acceleration valve 26 has, at its end opposite to that of the groove 29 for activating the needle valve 3, a curvature 41 which occupies a part of its periphery, acting as a cam to cause displacement of a rod 42 joined to the gasoline overfeed valve 43, as illustrated in Figures 6 and 9. The rod 42 can slide along a vertical groove 44 made on the face of the left part 1 of the carburetor which contacts the right part 6 thereof. In the idle position, the cam 41 of the rocker arm 28 maintains the rod 42 for activating the overfeed valve 43 in the raised position to allow fuel to enter the chamber 45 below its piston 46, against the action of the spring 47 of said valve 43, as illustrated in Figure 6. When the engine is accelerated, the rod 42 decends, as a result of the turn of the cam 41 of the rocker arm 28, injecting the fuel through the manifold 48 disposed above the diffuser 5, wherefore fuel will no longer be admitted in the valve 43 until a new initial idling position is reached, at which the rod 42 is again raised by the cam 41.
This overfeed pumping is also produced when the starter is pulled to start a cold engine, as subsequently explained with reference mainly to Figures 2 and 7.
The starter cable, not represented in the Figures, is fixed by the screw 49 to the pivot 50 protruding from an eccentric point of a lever 51 positioned without being able to turn at the end of the shaft 52 of the starter valve 54. Cn this same shaft 53 freely oscillates the end of a crank 54 hinged at its free end to the connecting rod 55 guided at its other end in a vertical rod 56 fixed in the base body 7 of the carburetor, through a hole made at its lower bent end, through which the rod 56 passes. This bent end has a prolongation 57 which is normally at its lowermost position due to the pressure exerted by a spring 58 which encloses the rod 56 and placed between its upper end and the bending of the connecting rod 55. The prolongation 57 of the connecting rod 55 is positioned in a lower plane at which it does not contact the cam 24 placed in the shaft 25 of the acceleration valve, when this reaches the idle position.
When the starter is pulled, referring to Figure 2, the lever 51 turns in an anti-clockwise direction, closing the valve 53 of the starter, until the crank 54 is pulled in the same direction by a lug 59 placed as a prolongation of the pivot 50 and protruding through the inner face of the lever 51, causing the extension of the connecting rod 55, the prolongation 57 thereof resting on the edge of the cam 24 which, as a result of the pressure exerted, turns in a determined degree to accelerate.
The turn of the cam 24 produces the same turn in the rocker arm 28, which cam 41 contacts the rod 42 for activating the overfeed valve 43, as a result of which fuel is pumped since the rod 42 can descend.
Both when pulling the starter and when initiating the acceleration process producing the overfeed pumping, when the shaft 25 of the acceleration valve 26 turns, an increase is produced in the diffuser section 5 and gasoline passage through the needle valve 3.
Figuresll to 16 show an embodiment of the mechanical connections made to obtain the automatic adjustment of the diffuser and gasoline passage sections simultaneously with the opening of the acceleration valve, as well as of the complementary elements of the diffuser whose movable part is displaced transversally to the shaft of the acceleration valve, to facilitate activation thereof. Like elements bear the same numerical references as in Figure 1 to 1C, adding a (') to facilitate understanding.
These Figures 11 to 16 show how the diffuser section 5' is automatically adjusted, since the movable body 10' of the diffuser is secured to a rod 60 displaced transversally to the shaft 25' of the acceleration valve. The free end of the rod 60 is pressed, overcoming the action of an anagonistic spring, by the free end of a lever 61, doubly bent, which pivots in a pin 62 fixed to the support 63 secured to the carburetor body. The lever 61 pivots at its free end in that of another lever 64, parallel to the rod 60 and provided with a projection 65 which is pulled in the turn of the acceleration lever 66, when housed in a slot 67 thereof.
According to these Figures 11 to 16, the simultaneous variation of the gasoline passage section in the needle valve 3', upon acceleration of the engine, is achieved through the bent lever 68, one of whose ends 69 is eccentrically anchored to the shaft 25' of the acceleration valve, whilst its other end 70, incorporating the screw 39 for adjusting the initial position of the needle 32' presses on this latter contrary to the recovery spring. The end 70 of the bent lever 68 is supported at the end itself of the needle 32' since it has an axial hole 71 in which the inner recessed end 72-of the screw 39' is housed. Thus, the projection 35 of the carburetor body is not required to fix a hinge pin 34, as in the case of the first embodiment (see Figures 5 and 6). Upon acceleration, the eccentric anchorage of the end 69 of this lever 68 controls the separation of the needle 32', in favour of its recovery spring, thereby increasing the passage section through the corresponding opening.
The gasoline overfeed valve 43, whose section can clearly be seen in Figure 6, instead of being activated by the rod 42 (see Figures 2 and 5) driven by the rocker arm 28 secured to the shaft 25 of the engine acceleration valve 26, is, in this preferred embodiment of the invention, determined by a diaphragm valve 73 whose section is clearly seen in Figure 14. The diaphragm valve 73 is activated, during the accelerating process, when its pusher 74 is pressed by the free end of a lever 75 pivoting in a pin 76 fixed to the valve support 77, which free end pivots, by means of a pin 78, in the end of a prolongation 79 of the lever 64 controlled by the displacement of the acceleration lever 66, since its projection 65 is incorporated therein.
Figure 2 shows that upon activation of the starter with its cable secured to the screw 49 of the lever 51 and turning the valve 53 for closure, the crank 54 is proportioned with an angular displacement and the prolongation 57 of the connecting rod 55 with an upward displacement, the upgrade cam 24 turning, thereby causing the partial acceleration of the engine upon turning of the shaft of the acceleration valve. Instead of this driving by levers, as shown in Figures 11 to 16, the invention proportions a simpler and more direct embodiment, si.nce the lever 80 for fixing the starter cable is provided with a cam profile 81 (see Figure 12) which impinges on another cam 82 secured to the shaft 25' of the acceleration valve, displacing it to a certain extent in an angular direction from the idle position, partially opening it, with the consequent increase in the diffuser section and gasoline passage in the needle valve.
The practical embodiment of the carburetor including the object of the invention: automatic adjustment of the diffuser and gasoline passage sections, corresponding to Figures 11 to 16, was described in Spanish Utility Model application No. 286,252 filed by the applicant on April 23, 1985.
In the embodiment of Figures 11 to 16, and referring mainly to Figure 13, the manifold communicating the needle valve 3' to the diffuser 5' takes place, instead of through a nozzle 4 (see Figure 4) positioned at the central zone of the diffuser 5, through a hole 83 facing that existing in the annular body 84 placed on the diffuser 5', below the cover 85, the fuel entering a tubular manifold 86 disposed axially to the diffuser. The annular,body 84 is placed in its correct position by a positioning screw 87.

Claims

1. A system for automatically adjusting diffuser and gasoline passage sections of carburetors, characterised in that during acceleration, simultaneously with the opening of the throttle valve, a diffuser section is increased gradually and a needle valve for the inlet of gasoline to the nozzle is opened; a gasoline overfeed valve is activated to initiate acceleration, which activation is interrupted at successive positions of the accelerator, said overfeed valve also being activated when starting a cold engine by pulling the starter, closing its throttle valve and partially opening the acceleration valve, with the consequent increase in the diffuser and gasoline passage sections.

2. A system as claimed in Claim 1, in which the diffuser section is varied since the carburetor body is comprised, in the zone occupied by the diffuser, of a separate portion positioned in a hollow made in the base of the carburetor body and retained by an upper cover thereof, said separate portion being divided into two parts, one of which is fixed in its location whilst the other, complementary of the former, can slide along its plane on close fitting support and guide surfaces, the movable part forming the diffuser being activated by an upgrade cam secured to the shaft of the acceleration valve, which presses the projection of a rod joined to the movable part of the diffuser to increase the section of the diffuser when accelerating, which is reduced when decelerating by means of a spring axial to the rod which maintains the diffuser at the position of minimum section; the part forming the diffuser being interchangeable, depending on the engine displacement, since its outer geometry is not altered.

3. A system as claimed in Claim 1 or 2, in which the section of the gasoline passage in the needle valve is varied by a normal rocker arm secured to the free end of the shaft of the throttle valve, provided with a groove including a 1u^g protruding from the end of the lever hinged in the carburetor body, whose free end contacts that of the needle aided by an antagonistic axial spring maintaining it in a maximum opening position, the passage section can be maintained in the original inoperative position by an adjusting nut and screw, since the end of the needle closes, in a lesser or greater degree, the corresponding opening, which passage has been previously selected depending on the engine displacement.

4. A system as claimed in Claim 3, wherein the rocker arm secured to the shaft of the valve has, at its free end, a curvature acting as a cam to cause displacement of the rod joined to the gasoline overfeed valve, only activated at the initiation of acceleration, the rod of the valve being raised to permit fuel to enter, against the action of an axial spring, when the idle position is reached, which is injected in the diffuser when the rod descends as a result of the turn of the cam upon acceleration, this overfeed pumping also being produced when the starter is pulled, the throttle valve of which has, at one of the ends of its shaft, a lever originating the upward displacement of a lever guided in a vertical rod fixed to the carburetor and provided with a projection pushing the cam to produce a partial acceleration of the engine.

5. A system as claimed in any preceding claim, wherein the diffuser section is automatically adjusted by an articulated series of rods from the shaft of the acceleration valve until the free end of the last lever, pivoted in a support fixed to the carburetor body, presses the front end of the shaft secured to the movable part of the diffuser.

6. A system as claimed in any preceding claim, wherein the simultaneous variation of the gasoline passage section in the needle valve is achieved through the eccentric anchorage of a bent lever at the inner end of the shaft of the acceleration valve, the free end of which incorporates the screw for adjusting the initial gasoline passage, which butts against the needle provided with an axial hole in which a cylindrical guide extension of the mentioned adjusting screw, is housed.

7. A system as claimed in any preceding claim, wherein the gasoline overfeed valve is simultaneously operated, during acceleration, since one of the articulated levers controlling the displacement of the movable part of the diffuser is provided with a prolongation in the end of which pivots a lever oscillating at its central zone at a fixed point of the carburetor body and the free end of which presses the pusher of the disphragm valve fixed to the carburetor body.

8. A system as claimed in any preceding claim, wherein when the starter is pulled, the gasoline overfeed pumping is also produced by a cam profile of the anchorage lever of the starter cable, which leads to another cam secured to the shaft of the acceleration valve, angularly displacing it to open the valve, with the consequent increase in the diffuser and gasoline passage sections.