GB2085520A - Gas and/or liquid fuel air valve carburettor - Google Patents

Abstract

A member 13 movable in response to a flow of air through the housing 1 is connected to at least one valve 11, 19 which opens an aperture 8, 20 in a chamber 6, 15 to which fuel is supplied so that fuel is discharged into the stream of air flowing towards an engine inlet manifold. The apertures 8, 20 may respectively supply gas and liquid fuel or different gas or liquid fuels. The air flow responsive member may be an angularly movable vane (41), Figs. 4 and 5 (not shown), which determines the lift of ball fuel valve (37). <IMAGE>

Description

SPECIFICATION Improvements in or relating to a carburettor This invention relates to a carburettor and more particularly relates to a carburettor for introducing a liquid or gaseous fuel to a stream of air to produce a fuel-air mixture for combustion in an internal combustion engine.

It is to be clearly understood that the fuel may be a liquid fuel such as petrol, diesel oil, paraffin, or the like or may be a gaseous fuel such as hydrogen, methane, propane, petroleum gas, or any other fuel which may be combined with a stream of air to form a fuel-air mixture capable of being ignited in an internal combustion engine.

Carburettors have been proposed before for use in connection with internal combustion engines, but such prior proposed carburettors have primarily been intended for use in connection with a liquid fuel, such as petrol. In such prior carburettors liquid fuel is supplied to a nozzle which is located in a venturi in an air flow passage leading to the inlet manifold of the engine. As air flows through the inlet passage a partial vacuum is created adjacent the nozzle thus withdrawing liquid fuel from the nozzle and mixing the fuel with the air flowing through the venturi.

For various reasons such prior proposed carburettors have been manufactured in relatively complex embodiments, and also such prior proposed carburettors have not been found to be satisfactory for use in connection with gaseous fuels, such as hydrogen or gaseous hydrocarbon fuels for example.

The present invention seeks to provide a carburettor that is suitable for use in connection with gaseous fuels. However it is to be appreciated that embodiments of the invention may also be found to be beneficial if used in connection with liquid fuels, and also it is to be noted that one embodiment of the invention comprises a carburettor that can be used with a liquid fuel and/or with a gaseous fuel.

According to this invention there is provided a carburettor for introducing a liquid or gaseous fuel to a stream of air to produce a fuel-air mixture for combustion in an internal combustion engine, said carburettor comprising a member adapted to move in response to a flow of air into said internal combustion engine, and a valve actuated in response to movement of the said member to control the discharge of said fuel to said stream of air.

Preferably said carburettor may include a housing, means to connect said housing directly or indirectly into an inlet manifold of an internal combustion engine by means of a butterfly valve or the like, said housing including an inlet aperture and said member, which is movable in response to a flow of air through said inlet aperture to the means connecting the housing to said inlet manifold.

Said member may comprise a member adapted to close the inlet aperture to the housing, and such a member may be directly connected to a valve member.

The carburettor may comprise a chamber to which said fuel is supplied, and said valve member may be located within said chamber, sealing an aperture in the chamber, so that movement of said member in response to a flow of air to said internal combustion engine causes said valve member to move into the chamber to open said aperture therein.

In a carburettor in accordance with the invention said member may alternatively, or additionally, be connected to a needle, said needle being inserted into a conduit or chamber to which fuel is supplied initially to seal said conduit or chamber, the arrangement being such that mvoement of said member causes said needle to be withdrawn from the orifice of said chamber or conduit.

Means may be provided, independently, of said valve, to discharge fuel into said stream of air, and such further means may comprise a manually adjustable valve connected to a fuel supply conduit. Such manually adjustable valve may be operated to supply fuel to the stream of air to maintain the engine operating in a suitable "tick over" mode.

In one preferred embodiment of the invention said member comprises a rotatable paddle member located within the housing, said inlet aperture being located generally on one side of said paddle member, the housing also including an aperture communicating with said inlet manifold generally on the other side of said paddle member, the arrangement being such that in operation of the carburettor said paddle member rotates to permit air entering the housing through the inlet aperture to leave the housing through the aperture communicating with the inlet manifold, the paddle member being connected to said valve.

Preferably the valve comprises a cap member threadably mounted on a threaded end of a fuel supply conduit, said cap member including a chamber communicating with the exterior of the cap and communicating with the interior of the fuel supply conduit, the arrangement being such that the cap member may be moved from the position in which the conduit is sealed to a position in which the conduit is opened in response to movement of the paddle member in response to said flow of air.

Preferably a valve member in the form of a ball is provided within said chamber within the cap to seal said conduit.

It is to be appreciated that a carburettor in accordance with the present invention may be mounted on the air inlet of a conventional carburettor or may be utilised instead of a conventional carburettor.

In order that the invention may be more readily understood, and so that further features thereof may be appreciated, embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which: FIGURE 1 is a schematic part cross sectional view of one embodiment of a carburettor in accordance with the invention; FIGURE 2 is a view corresponding to Figure 1 showing the various parts of the carburettor in the positions that they occupy when the carburettor is in use; FIGURE 3 is a corresponding cross sectional view of a second embodiment of a carburettor in accordance with the present invention; FIGURE 4 is a top plan view of a further carburettor in accordance with the invention with the cover thereof removed, but the position of an aperture in the cover shown phantom; and FIGURE 5 is a schematic sectional view taken on the line V-V of Figure 4.

Turning initially to Figures 1 and 2 of the accompanying drawings a carburettor, that is to say a device for mixing air and a gaseous or volatile fuel, in accordance with the invention is illustrated. The carburettor comprises a generally tubular casing 1. The lower end 2 of this tubular casing is open, and the casing is adapted to be connected, by means of a butterfly valve, to the inlet manifold of an internal combustion engine.

The casing 1 may be directly connected to the manifold, by means of the butterfly valve or air filters or the like may be interposed between the casing 1 and the inlet manifold.

At its upper end the casing 1 is provided with a readially inwardly directed flange 3 which defines a central circular aperture 4 in the top of the casing. A first fuel supply conduit 5 extends from the exterior of the casing to a chamber 6 defined by an appropriate housing 7 located within the casing 1. The housing 7 defines an aperture 8 in the upper surface thereof. The aperture 8 is sealed by means of a valve member 9 which has an elongate shank 10 passing through the aperture 8 and an enlarged valve head 11 connected to the shank 10 and located within the chamber 6. An "0" ring of appropriate resilient material is mounted between the valve head 11 and the portion of the housing 7 defining the aperture 8.

The upper end of the shank 10 is connected to a horizontal disc 13 which abuts the undersurface of the radially inwardly directed flange 3 thus sealing the aperture 4.

It is to be appreciated that the fuel supply conduit 5 is intended to supply a gaseous fuel, such as hydrogen, liquid petroleum gas, natural gas, or other corresponding fuel to the chamber 6.

A second fuel supply conduit 14 also extends from the exterior of the casing 1 to a chamber 15 defined within a housing 1 6 which is also located within the casing 1. Mounted on the housing 1 6 is a guide bush 1 7 and a rod 1 8 which is connected, at its upper end, to the disc 13, passes slidably through the bush and supports, at its lower end, an upwardly directed needle 19. The needle is inserted into the lower open end 20 of the chamber 15, thus sealing the chamber 15. It is to be appreciated that the second fuel supply conduit 14 is intended to supply a liquid to the chamber 1 5, such as petroleum, diesel oil, paraffin or the like.

It is to be appreciated that Figure 1 illustrates the carburettor in the position occupied when the engine to which the carburettor is connected is not operating. Thus both the chamber 6 and the chamber 1 5 are sealed, thus preventing any fuel from escaping from those chambers.

When the engine to which the carburettor is started, initially the starter motor is operated causing the motor to turn over. This will create a partial vacuum within the inlet manifold and thus the pressure within the interior of the casing 1 will fall. Consequently, the air pressure acting on the exposed upper surface of the disc 13 will press that disc downwardly, thus also driving the valve head 11 downwardly and the needle 19 downwardly. Thus the various illustrated components of the carburettor enter the position schematically illustrated in Figure 2. It will be appreciated that if fuel is being supplied to either or both of the chambers 6 and 15, then when the components of the carburettor have the positions illustrated in Figure 2, then fuel escapes from either or both of the chambers 6 and 1 5 into the interior of the casing 1.There is, of course, within the casing 1, a down draft of air flowing in through the aperture 4 formed in the upper part of the casing, and this down draft of air will entrain the fuel escaping from the chambers 6 or 1 5 and thus lead that fuel through the inlet manifold into the cylinders of the engine. As the fuel is entrained in this way the fuel is intimately mixed with the air so a suitable fuel-air mixture is introduced to the cylinders of the internal combustion engine.

It is to be appreciated that the quantity of fuel discharged from the chambers 6 or 1 5 will depend upon the degree of depression of the disc 1 3, and this in turn, will depend upon the rate of flow of air into the inlet manifold. This may be controlled, in a conventional manner, by means of a throttle connected to the butterfly valve.

It is to be appreciated that the described carburettor may be used solely with a gaseous fuel supplied to the chamber 6, or solely with a liquid fuel supplied to the chamber 1 5. Alternatively fuels of both type may be supplied to both chambers, and in such a case appropriate control means may be made available to the driver of the motor vehicle fitted with the carburettor to enable the driver to select either liquid fuel or gaseous fuel.

It is to be appreciated that whilst the embodiment illustrated and described in Figures 1 and 2 is provided with means for dispensing two types of fuel into the down draft of air, one embodiment of the invention may comprise two chambers identicai with the chamber 6, each having an associated valve, corresponding with the valve 9, and such a carburettor may be used to dispense two different types of gaseous fuel.

Similarly it is to be appreciated that in another embodiment of the invention the carburettor may include two chambers corresponding to the chamber 15, each such chamber being associated with a respective needle 1 9. Thus such an embodiment is utilised to dispense two different types of liquid fuel.

Figure 3 illustrates a second embodiment of the invention. However it will be readily appreciated that certain components of the embodiment shown in Figure 3 correspond with components of the carburettor shown in Figure 1 and like reference numerals have been used for like parts wherever applicable. Such parts need not be redescribed here.

It will be noted that the embodiment of the invention shown in Figure 3 includes a conduit 21 which communicates with the conduit 5 that supplies the gaseous fuel to the chamber 6. The conduit 21 defines a valve seat 22. A valve pin 23 is mounted on the end of a threaded shaft 24 which threadedly engages the threaded interior of an extension 25 of the conduit 21. The threaded shaft 24 is provided, at its other end, with a knurled knob 26. The valve pin 23 is located within a chamber that communicates, by means of a port 27 with the interior of the casing 1.

The carburettor shown in Figure 3 operates in a very similar manner to the corresponding portion of the carburettor shown in Figures 1 and 2.

However the position of the valve pin 23 relative to the seat 22 may be adjusted by means of the knob 26, and when the pin 23 is spaced from the seat 22 a certain amount of fuel from the fuel supply conduit 5 will be directed into the interior of the casing 1. Thus a certain regulatable quantity of fuel may be supplied to the engine during "tick over" or "idling" of the engine.

It is to be appreciated that when the carburettor shown in Figure 3 is utilised in a motor vehicle a separate on-off valve will have to be provided in the fuel supply conduit 5, since otherwise if the vehicle is left unattended with the valve pin 23 spaced from the valve seat 22 gaseous fuel will escape through the port 27.

Referring now to Figures 4 and 5 of the accompanying drawings in a further embodiment of a carburettor in accordance with the present invention a housing 28 is provided, the housing being circular in plan. The upper part 29, of the housing is closed, apart for an arcuate aperture 30 which is shown in phantom in Figure 4. The lower part of the housing has a hollow spigot 31 which can be connected to an inlet manifold by means of a butterfly valve as described above. The hollow spigot 31 communicates with the interior of the housing 28 by means of an arcuate aperture 33 formed in the wall 34 that defines the bottom of the housing 28.

A fuel supply conduit 35 extends through the wall of the hollow spigot 31 and then extends upwardly centrally through the wall 34 into the interior of the housing 28. The portion of the fuel supply conduit 35 that extends into the housing 28 is externally threaded 36. At the open end of the conduit 35 a ball 37 is provided which is dimensioned to be accommodated within the open end of the central bore of the conduit 35 in order to seal the conduit. A cylindrical cap 38 is screw threadedly mounted on the screw threaded portion 36 of the conduit 35. The cap 38 defines an inverted seat or recess 39 that can cooperate with the ball 37 to press the ball into sealing engagement with the open end of the conduit 35.

The ball is accommodated within a chamber defined within the cap 38. The cap is provided with a radially extending bore 40 that connects the chamber within the cap that accommodates the ball 37 with the exterior of the cap.

Mounted on the cap is a radially extending paddle 41 which extends from the cap substantially to the walls of the housing 28. As can be seen in Figure 4 the paddle lies over the arcuate aperture 33 and the bore 40 within the cap 38 opens on the side of the paddle 41 that is adjacent to the aperture 30 formed in the upper part 29 of the housing 28. A spring or other means, not shown, is provided to bias the paddle in the direction of the arrow 42 shown in Figure 4.

It is to be noted that an upstanding wall 43 is provided which extends radially from the cap 38 to the periphery of the housing, this wall serving to seal the housing so that, in use of the carburettor air cannot flow through the aperture 30 and thence anti-clockwise around the cap 38 to the arcuate aperture 33.

When the illustrated carburettor is utilised the hollow spigot 31 is connected, by means of a butterfly valve, to the inlet manifold of an internal combustion engine. When the internal combustion engine is started a vacuum is created in the inlet manifold and thus the pressure within the housing falls. Air enters the housing through the arcuate aperture 30 formed in the top of the housing and is constrained to flow towards the arcuate aperture 33. Thus the air impinges upon the paddle 41 thus rotating the paddle, and the cap 38, in an anticlockwise direction against the biassing force that biasses the paddle in the direction of the arrow 42. The degree of movement of the paddle is dictated by the rate of airflow since a higher air flow rate will cause the paddle to move further than a lower flow rate.As the paddle moves from its initial position in which the paddle is located between the aperture 30 and the aperture 33, and in which the ball 37 is pressed into sealing engagement with the end of the conduit 35, the cap rises by virtue of its screw threaded mounting on the threading 36 of the conduit 35. Thus the ball 37 is released from sealing engagement permitting fuel to flow through the bore 40. Thus the fuel is discharged into the stream of air flowing from the aperture 30 to the aperture 33, and the fuel is thus mixed with the air before the mixture passes into the inlet conduit.

Whilst the invention has been described with reference to preferred embodiments it is to be appreciated that many alterations or modifications may be made. However, it is to be noted, that in each embodiment a member is provided which moves in response to a flow of air into the inlet manifold of an internal combustion engine, and movement of such a member results in the opening of a valve which admits a flow of fuel to the air that is being drawn into the inlet manifold.

Whilst in the specifically described embodiments the movable member is directly connected to a part of the valve it is to be appreciated that the member moving in response to the flow of air may cause the actuation of a linear motor or some other electronic motor, or even a hydraulic device which actuates the valve. Thus it is envisaged that whilst the presently described embodiments are all of a simple nature, more complex embodiments could readily be designed.

It is to be appreciated that in the preferred embodiments of the invention there is a preferred relationship between the rate of flow of air to the inlet manifold and the rate at which fuel is discharged into that flow of air so that an appropriate mixture is fed to the inlet manifold at all times. Thus it will be appreciated that as the member is moved further from its initial position in response to an increasing flow of air, so the valve is opened further permitting more fuel to be discharged.

Claims (15)

1. A carburettor for introducing a liquid or gaseous fuel to a stream of air to produce a fuelair mixture for combustion in an internal combustion engine, said carburettor comprising a member adapted to move in response to a flow of air into said internal combustion engine, and a valve actuated in response to movement of the said member to control the discharge of said fuel to said stream of air.

2. A carburettor according to claim 1 wherein said carburettor includes a housing, means to connect said housing directly or indirectly to an inlet manifold of an internal combustion engine by means of a butterfly valve or the like, said housing including an inlet aperture and said member which is movable in response to a flow of air through said inlet aperture to the means connecting the housing to said inlet manifold.

3. A carburettor according to claim 1 wherein said member comprises a member adapted to close the inlet aperture to the housing.

4. A carburettor according to claim 3 wherein the said member is directly connected to a valve member.

5. A carburettor according to any one of the preceding claims comprising a chamber to which said fuel is supplied wherein said valve member is located within said chamber seal an aperture in the chamber, so that movement of said member in response to a flow of air to said internal combustion engine causes said valve member to move into the chamber to open said aperture therein.

6. A carburettor according to any one of claims 1 to 4 wherein said member is connected to a needle, said needle being inserted into a conduit or chamber to which fuel is supplied initially to seal said conduit or chamber the arrangement being such that movement of said member causes said needle to be withdrawn from the orifice of said chamber or conduit.

7. A carburettor according to any one of claims 1 to 6 wherein means are provided, independently of said valve, to discharge fuel into said stream of air.

8. A carburettor according to claim 7 wherein said further means comprise a valve connected to a fuel supply conduit.

9. A carburettor according to claim 8 wherein said valve is a manually adjustable valve.

10. A carburettor according to claim 2 wherein said member comprises a rotatable paddle member located within the housing, said inlet aperture being located generally on one side of said paddle member the housing also including an aperture communicating with said inlet manifold generally on the other side of said paddle member, the arrangement being such that in operation of the carburettor said paddle member rotates to permit air entering the housing through the inlet aperture to leave the housing through the aperture communicating with the inlet manifold, the paddle member being connected to said valve.

11. A carburettor according to claim 10 wherein said valve comprises a cap member threadably mounted on a threaded end of a fuel supply conduit, said cap member including a chamber communicating with the exterior of the cap and communicating with the interior of the fuel supply conduit, the arrangement being such that the cap member may be moved from a position in which the conduit is sealed to a position in which the conduit is opened in response to movement of the paddle member in response to said flow of air.

1 2. A carburettor according to claim 11 wherein a valve member in the form of a ball is provided within the said chamber within the cap to seal said conduit.

13. A carburettor substantially as herein described with reference to and as shown in Figures 1 and 2 of the accompanying drawings.

14. A carburettor substantially as herein described with reference to and as shown in Figure 3 of the accompanying drawings.

15. A carburettor substantially as herein described with reference to and as shown in Figures 4 and 5 of the accompanying drawings.

1 6. Any novel feature or combination of features as herein disclosed.