AU2004201642A1 - Carburettor for Automotive Use - Google Patents

Description

Title: Carburettor for Automotive Use.

DESCRIPTION

What is described is an improved method of fuel and air mixing and fuel to air ratio control, primarily intended for use as a carburetor for the internal combustion engine.

Also described is an improved method of construction for a carburettor.

Throughout this document the singular may mean the plural and an orifice may be referred to as a jet. A venturi may be a bored hole shaped to promote airflow or not shaped to promote airflow. An airflow orifice may be referred to as a venturi. The act of machining to remove or replace material has an equivalent outcome by casting material or injection molding material. The mains system may refer to the liquid distribution tube or the supply tubes. A carburettor may be a device to meter fuel in response to airflow that causes a pressure difference between the atmospheric pressure of the fuel bowl and the venturi effect of the air flow orifice or it may by a device to meter fuel in response to airflow that causes a pressure difference between a mechanically pressure regulated fuel supply system and the venturi effect of the air flow orifice.

BACKGROUND

The principal of maintaining a desired fuel to air ratio by introducing air into an emulsion chamber to correct for otherwise enrichment of the mixture that would occur due to single point sensing has been the main method of choice for carburetor manufacturers.

This is commonly called the auto-correcting carburetor principle. The early designs of fixed venturi carburetors sensed the air velocity at the center of a venturi by a tube inserted into the centerline of the venturi. The opposing end of this tube was submersed into the fuel chamber. An increasing air volume discharging through the venturi caused sufficient pressure differential between the end of the tube inserted onto the fuel chamber and the end of the tube in the venturi to cause fuel to flow into the center of the venturi. This method meant that the fuel ratio could be determined by the use of an orifice placed for convenience at the base of the tube. It was soon realized that additional control was needed because of the pressure gradient of the air due to friction upon the venturi walls. This effect resulted in increasing richness of the fuel to air ratio as the volume of airflow increased. A satisfactory solution was found in the invention of the auto-correcting principle.

Part of the auto-correcting principle involves the use of an emulsion tube.

Emulsion tubes allow air to be introduced and thereby acting as a compensating medium into the fuel delivery tubes by reducing the volume of fuel delivered. A further part of the auto-correcting principle involves the use of a main venturi with a smaller venturi (commonly and hereafter referred to as a 'booster venturi') located so as to have some communication of effect between the two venturi. The smaller venturi also has the fuel emulsion system connected to it. The volume of fuel exiting into the small venturi gradually restricts the volume of air passable by the small venturi thus causing a mixture ratio change. Various techniques of jetting of fuel passages and or air passage3 and pressure take off points combine to control the fuel to air ratio the engine receives. The head of pressure of fuel within the emulsion tube also affects the volume of air introduced. The emulsion tubes generally have to be arranged in a vertical configuration so that as the fuel level changes within the emulsion tube, more or less air introduction holes are exposed.

In the past carburettors have required a considerable time to disassemble and change components for the purpose of effecting a change of tune to the engine. There have been many designs of carburettor that utilized modular construction but these modules have still taken considerable time to change. Simple functions such as altering the main jet mixture usually require draining of fuel and removal of the fuel bowls. A common 4-venturi carburettor in use predominantly on V8 engines requires working on the carburettor over the top of the engine in order to tune the carburettor. Presented is a carburettor that enables a downdraft configuration of any number of venturi and tuning time is reduced to a few second or a few minutes. There is no need to drain fuel so safety is improved. There is no need to work for a period of time over a hot engine because the entire metering system can be removed and replaced in a nominal time of 20 seconds.

Another advantage of the carburettor presented is the ability to change the interchangeable plates that also incorporate the venturi section. The carburettor presented can have any of the factors of air flow restriction, main jet ratio, transfer jet ratio, idle jet ratio, accelerator pump shot effect, idle butterfly angle compensation, idle cylinder distribution, transfer fuel cylinder distribution, or vacuum ignition timing port changed in a nominal period of 20 seconds.

THE INNOVATION

PRESENTED.

The following is a general description of the construction and operation of the carburettor.

The carburettor is constructed with a chassis to enable modular construction and assembly. The chassis section of the carburettor may hereafter be referred to as the main body or the middle section or the chassis. The fuel mixture control systems and venturi are formed by the assemblage of plates attached to the air entrance face of the chassis.

The fuel supply systems may be attached to the side of the chassis. A throttling plate may be attached to the base of the chassis to control the regulation of airflow rate through the carburettor. The throttling plate may contain inserted plates to assist in control of fuel mixture.

The construction of the carburettor involves various levels and functions sandwiched on top of each other, with each level/functional unit easily and quickly removable and replaceable. This provides far greater flexibility in quickly modifying or tuning the carburetion of an engine.

The carburettor may utilize a well known physics phenomena of gas flow and pressure that occurs in holes of less than 1mm in diameter and less than 1mm in length of hole. This physics phenomena enables a simple metering system to be produced that in turn enables the elimination of the conventional air and fuel emulsification systems in common carburettor use. This physics phenomena may be used for the design of the main fuel mixture and atomization system. The elimination of the air bleed/emulsion main jet principal in common use by existing carburettor designs reduces the number of components and simplifies the tuning of the main fuel mixture and atomization jetting system.

The main jet fuel mixture control and atomization device can be inserted within a plate and held in place by the sandwiching of the layers of plates or plate to chassis sandwiching. A single or low number of bolts may supply the force necessary to seal the plates thus decreasing the time spent to effect a plate or component change.

The device for main fuel mixing and atomization ideally causes the fuel to exit into the air stream at approximately 90 degrees to the air flow direction, therefore creating the maximum shearing of the fuel into droplets. We seek to prove that the design of this main fuel mixing and atomization device is inventive over previous designs that have purposely introduced air into the fuel stream before the fuel interaction with the atmosphere in the venturi.

One of the factors affecting the pressure gradient of air flowing through a venturi is the friction of the air in contact with the walls of the venturi. This pressure gradient may be measured in any direction. The pressure gradient measured as a cross section through the venturi will be different at any place along the venturi. This is due to changes in friction and conversion of energy associated with length and diameter of the venturi.

When a fuel carrying tube is placed across a venturi or a straight bored hole and the tube is formed with a multitude of holes displaced across the chord formed, the fuel exits each of the holes in response to the pressure gradient at the fuel exit point. When sufficient numbers of holes are placed across the chord the fuel to air ratio is more consistent than a single point sensing tube. The need for auto-correcting principles is reduced. Another advantage of this innovation is that the fuel droplets, by exiting into multiple areas of the venturi, are in contact with a greater amount of unmixed air. Unmixed air may be considered to be dry and hot relative to air that has been in contact with fuel and thus cooled and moisturized by the percentage of vaporized and liquid fuel present. Because this innovation increases the amount of air in contact with the fuel droplets at the early stage of mixing in the carburetor the energy potential for vaporization is increased. The rate of vaporization of a droplet of fuel is due to the energy transfer rate between the fuel droplet and the surrounding atmosphere. Therefore small multiple droplets of fuel totaling a given mass will expose a greater surface area of liquid to the atmosphere compared to a single large droplet of fuel of the same mass. This increases the vaporized percentage of fuel in the intake system.

The innovation of the distribution tube allows the fuel droplet size and the number, shape and placement of the exit holes to influence the exit speed of the fuel from the fuel tube into the atmosphere. The droplet size may be influenced by the fuel outlet orifice shape and area. The number of orifices will influence the exit speed of the fuel from the orifice. A single orifice has the highest fuel exit speed from the orifice, where as multiple orifices reduce the fuel speed due to a lesser area to circumference ratio therefore having a greater friction component. When the fuel speed within the orifice is reduced the amount of fuel acceleration required in the atmosphere to meet the air speed is increased. This increased acceleration rate occurring in the atmosphere requires a greater energy input to the fuel from the atmosphere of the venturi and therefore greater vaporization occurs. These factors above influence the equality of fuel to air ratios delivered to the cylinders of a multiple cylinder engine. Equality of mixture distribution is improved by achieving higher levels of vaporization. The effect of higher vaporization of the fuel is to promote a more consistent fuel to air ratio because vaporized fuel behaves in a similar way to the air flow patterns whereas fuel that is present as a liquid is subjected to greater inertia influences.

The simplicity of this fuel metering system enables the entire main fuel supply metering equipment to be contained in a small depth of venturi, typically but not limited to the range of 15mm to 25mm in depth. This enables the venturi and fuel metering system to be formed entirely in a removable plate. The distribution tube may be vertically or horizontally or obliquely mounted whereas emulsion tubes of conventional carburettors generally have to be arranged in a vertical configuration so that as the fuel level changes within the emulsion tube, more or less air introduction holes are exposed.

The limitations of conventional emulsion tubes adds vertical height to the metering system whereas the distribution tube described may be held horizontally by the plates reducing the vertical height of the carburettor and allowing simple removal of the plates and or the distribution tube.

Multiple plates may be pre set with different combinations of features and quickly changed for testing or improvement of the engines performance. The plates may also be installed on top of one another to affect fuel ratio control. This feature may also be used in conjunction with combustion enhancing substances such as nitrous oxide gas or nitro methane fuels.

The surfaces of the plates may form fuel and or air conveyance passages. These passages may be formed by simple milling operations such as milling a channel upon the contact surfaces of the plates. The passages may also be formed during a casting or injection molding process. A gasket may form a chamber in conjunction with the passages and be able to hold fuels and air from leakage to undesired areas and may also seal the contact surfaces of the multiple plates. The clamping force achieved by bolting the multiple plates to the body of the carburettor may be sufficient to form an effective seal.

The removable plates may contain other components of the operation of the carburettor. These components may form all or part of the engine idle system or all or part of the engine slow running above idle speed system. These systems are generally used to supply fuel at correct ratios to the engine at air velocities that may be too slow for the main supply system to operate efficiently. The idle system normally consists of an air bleeding jet and a fuel jet. The fuel jet is normally adjustable so as to obtain engine run quality. The slow running above idle speed system (commonly and hereafter referred to as the transfer system) usually consists of an air bleeding jet and a fuel jet. Because the plates may contain different components that interact to fully control or partially control the delivery rate and condition of fuel, the alignment of components relative to one another may become a useful feature of the plate mounting system. For instance the alignment and positioning of the transfer jet outlet in relation to the transfer system air bleed jet may be so that the air flow stream and the fuel flow stream collide or interact in such a way that promotes various desired features of atomization. Some examples are to promote circular flow patterns into drilled passages or circular flow patterns into square or rectangular passages or other polygon shape passages. The passages for the containment of fuel and or air may be fitted with a variety of components to promote mixing of fuel and air. These components may be inserted into the passages and contained by the sandwiching effect of the assembly of the plates and or gaskets. The plates may contain other parts of or entire systems that are designed to alter the mixture during special circumstances such as acceleration or deceleration. Typically these are called accelerator pumps, power valves and fuel shut off solenoids.

Internal combustion engines generally open the inlet valve before the exhaust cycle is completed; this intentionally causes exhaust gas pressure to exit into the inlet tract of the engine. This reversal of flow may be detrimental to the carburettors fuel metering. The carburetor may also incorporate into the design an additional chamber above the throttling butterfly valves but below the removable plate. A common carburetor in use is four venturi arranged in a downdraft configuration. These carburetors have the venturi shape extending through to the throttling butterfly valves with each venturi in communication only with the throttling valve directly beneath it. In the design presented the carburetor may have a chamber formed in the section of the body between the plate containing the venturi and the section containing the throttling valves. The chamber may be large enough to cover the area between all venturi and all throttling valves or the chamber may be divided. This chamber may be shaped to reduce the effect of the intensity of any reversal in airflow direction pulses and the subsequent effect upon the main fuel supply system. The chamber also promotes fuel mixing by reducing the velocity of the airflow in the chamber region. The reduction of air velocity creates turbulence that promotes mixing of the fuel droplets.

The carburetor may contain a jet in a removable plate or in the body that controls an amount of air flow bypassing the throttling valve from the upper side of the throttling valve to the lower, engine vacuum side. This jet may be called the butterfly angle compensation jet. Adjustment of this jet is used to alter the angle of the blade of the throttling valves and still achieve a correct idle speed for the engine. The principle of allowing airflow to occur through a drilled hole in the throttling valve in order to perform the adjustment described is in common use however this procedure is limited and time consuming to alter or tune. This control is used independently from the idle speed adjustment screw common to all carburetors.

Another configuration of use of the carburettor is to remove the chassis and fuel level control bowls and substitute an adaptor allowing connection of the mixture control plates to conventional fuel injection system and equipment. The adaptor may be used to attach the mixture plates to within a close proximity to the throttling plate. These injection systems are of various designs. The principles of operation include but not limited to computer controlled and mechanical controlled fuel injection equipment.

Alternatively the fuel injection equipment may be connected directly to the mixture control plates and the mixture control plates may be attached directly to the throttling plate.

There are fuel injection systems known as full flow systems. These systems are in common use though out speedway racing. These systems supply fuel regulated by mechanical means of controlling pumping rates and valves and regulators. Various hosing designs and various injector nozzle designs convey the fuel to the engine inlet manifold. These systems are ideally suited for fuel supply to the mixture control systems of the carburettor described. These full flow systems usually require controlled amounts of vacuum to operate at low airflows and by connection of the hoses to the mixture plates the systems receive controlled vacuum and partial carburetion. This configuration of facilitating fuel flow into the mixture control plates allows the fuel to be injected at a similar point as a carburettor would supply fuel to the air stream if so desired.

Another configuration of use of the carburettor is to install injection nozzles either into one of the existing plates or by installing an additional plate in either or an above and or below the throttling valve position. The purpose of this addition of injection nozzles is to enable the effective interaction of the principles and benefits of carburetion and the principles and benefits of fuel injection. An example of use is to supply 80% of the engines fuel requirement by the carburettor and the remaining 20% of the fuel requirement by the injection system. Using the injection and carburetion in this combined manner allows the injection system to fine-tune the engine emissions and or power output. An advantage achieved is that an engine of high fuel demand requires high cost high flow injectors in order to totally fuel the engine by the injection system. Carburettors are able to supply large quantities of fuel for a low cost item. By combining the 2 systems the cost of fueling a high demand engine is reduced. The benefits of fuel injection for emission control and fine-tuning are still retained. Another advantage of fuel injection combined with carburetion is that injecting fuel at or near to the inlet valve reduces fuel wastage upon the walls of the inlet manifold. A predominant problem with carburettors is the addition of fuel necessary for quickly responding acceleration of the engine under load. This condition requires the addition of extra fuel. This addition is commonly referred to as an accelerator pump shot. The location of this accelerator pump shot is usually above the main venturi. By injecting fuel at or near to the inlet valve the response time of the mixture change in the cylinder is reduced. By injecting the extra fuel at or near to the throttling valve the response time of the fuel mixture within the inlet manifold is reduced.

The carburettor may be assembled in one form by installing the plate of drawing five on top of the plate of drawing four with the liquid distribution tube of drawing seven inserted within the plate of drawing four and held in place and sealed by the clamping force of the plate in drawing five. All the plates of the carburettor may be held in place by a single generally central bolt.

Description of operation Referring to drawing number one.

Part one is a drawing of the liquid distribution tube showing the liquid distributor orifices.

Part two is a member made of suitable material to form an orifice within.

Part three is an orifice through which a gas is drawn through by a variation in pressure created on opposing sides of the division formed by part two.

Part four is an orifice to supply liquid to the liquid distributor tube.

Part two may be referred to as a plate of the carburetor.

Part three is commonly referred to as the venturi.

A carburetor contains elements to control fuel supply quantity and level and a restriction to atmosphere flow to take advantage of the venturi principle.

When an engine creates a partial vacuum below the carburetor the difference in atmospheric pressure causes the atmosphere to flow through the aperture formed in part two. Part one causes a further restriction to the aperture in part two. The maximum restriction to the atmosphere's flow is on a plane near the measurement line The fuel outlet orifices are located near this point of maximum atmospheric restriction. This causes a sufficiently high-pressure differential to promote fuel flow from a supply bowl.

The amount of fuel flow is dependent upon the pressure differential and the frictional resistance to flow in the fuel system and the laws of physics that apply. It is understood that fluid flow through a tube and or an orifice eventually reaches a critical velocity where no increase in flow occurs even though the energy creating the flow may be increased. It is understood as advanced physics or as a phenomena of physics that the resultant flow due to a pressure differential across an orifice of less than approximately 1mm and shorter than approximately 1 mm is linearly related to the pressure differential only and that this is not the case with orifices of larger diameter and or length. Orifices of larger diameter and or length are subjected to the influences of frictional flow. Increasing the frictional resistance to flow results in a lower weight of fuel to weight of air causing a leaner mixture to be delivered to the engine.

The diameter of the fuel distribution tube may be altered to control the effect of one of the friction resistance areas. A smaller diameter tube has a greater friction component for any given flow. The effect of the friction is to cause a reduction of fuel to air ratio. The smaller the diameter of the tube the greater is the fuel to air ratio reduction at higher fluid flow rates.

The wall thickness of the fuel distribution tube at the point where the fuel discharge orifice is formed may be altered to control the effect of one of the friction resistance points. A thicker wall may due to the length of the orifice have a greater friction component for any given flow.

The cross section area of the chamber to deliver fuel to the jetting orifices may be altered to control the fuel flow relative to increase of airflow.

The point upon the circumference of the fuel distribution tube where the fuel orifices are formed may be altered to control the pressure differential and or the speed of airflow past the orifice.

The point upon the length of the fuel distribution tube where the fuel orifices are formed may be altered to control the amount of pressure differential upon each individual orifice. An orifice that is placed near the wall of the venturi will deliver fuel in response to a lesser pressure differential due to the reduced velocity of the air stream at the wall of the venturi.

It is by combining some or all of these principles of physics of fluid flow that the distribution tube is able to effectively carburet without the necessity to use common systems in use by other carburettors.

Referring to drawing two.

The angle of the fuel distribution tube relative to the surface of the fuel may be altered to control the amount of pressure differential necessary to promote fuel flow from the fuel discharge orifice. This causes the fuel to air ratio to gradually increase in response to increasing airflow.

The cross sectional area of the venturi is greater the further away from the liquid distribution tube as measured in the region marked This causes the air pressure to gradient according to the area gradient. The liquid exiting the fuel distribution holes at or near the position marked occurs at a higher total flow rate of air through the venturi.

Thus creating a 'ramping up' affect of fuel flow that may be desired at the initial onset of flow from the distribution tube.

This element of control may be used in a combination or a singular manner resulting in a fuel mixture control device capable of producing a variable ratio of fuel to air with increasing or decreasing air flow quantities or a consistent air fuel ratio with increasing or decreasing air flow quantities.

Referring to drawing three.

Shown is a plan view of a four-venturi removable top plate. Parts of the plate are formed in symmetry so the labels are only on one quarter of the view.

The transferjet is in communication with the fuel supply in the reservoir via a passage in the main body of the carburetor. The communication point may be wholly or partially connected to the main system fuel pick up point or it may be separated so as to be independent of the mains fuel flow dynamics.

The transfer air bleed may be located above the tube delivering the mixture to the base area of the carburetor.

The idle jet is in communication with the fuel supply in the reservoir via a passage in the main body of the carburetor. The communication point may be wholly or partially connected to the mains system fuel pick up point or it may be separated so as to be independent of the mains fuel flow dynamics. The communication point may be wholly or partially connected to the transfer system fuel pick up point or it may be separated so as to be independent of the transfer fuel flow dynamics.

The idle air bleed may be located above the tube delivering the mixture to the base area of the carburetor. The idle system fuel may exhaust into the engine manifold area directly after the butterfly valves or it may exhaust into the air stream flowing past the butterfly valves.

The butterfly angle jet is at the top of a hole formed through the middle section of the carburetor and through the base section. It allows air leakage control to alter the blade angle of the throttling valve relative to the transfer system outlet point. The idle system fuel may exhaust into the passage of the air flowing via the butterfly angle jet.

The accelerator pump delivery point may have a variety of fuel directional control devices installed to it so as to fine tune the accelerator pump time of shot duration or direction of flow. It may have a liquid distribution tube utilizing the principles of the liquid distributor tube as per the subject of this innovation and discharge into the main venturi or above or below it.

The use of a central clamping bolt has been found to be of sufficient force to seal the fuel passages when sealed with a suitable gasket and tightened with a suitable bolt.

The use of a minimum number of fixing points promotes fast removal times for quick change tuning because the features of venturi size and mixture control circuits may be all contained within the quickly removable top plate.

REFERRING TO DRAWING

FOUR.

Shown is plan and side and end views of a four-venturi removable plate. The plate is machined so as to receive a main jet fuel mixture control and atomization device. An example of a form of this device is shown at The plate is machined so as to receive jets to control fuel supply The plate is machined so as form passages or holes for fuel flow. The plate is machined so as to form passages for airflow. The orifice may be a circular orifice or it may be a free-formed orifice eg. Including but not limited to Square or Rectangular or elliptical or oval or other geometrical shape. The external shape of the plate may be as illustrated or any other geometrical shape suitable for an intended purpose.

REFERRING TO DRAWING FIVE.

Shown is plan and side and end views of a four-venturi removable plate. The plate is machined so as to receive jets to control airflow The plate is machined so as form passages for fuel and or airflow The plate is machined so as to form passages for airflow The orifice may be a circular orifice or it may be a free-formed orifice eg.

Including but not limited to Square or Rectangular or elliptical or oval or other geometrical shape. The external shape of the plate may be as illustrated or any other geometrical shape suitable for an intended purpose.

REFERRING TO DRAWING SIX.

Shown is an isometric view of a two-venturi removable plate. The plate is machined so as to receive jets to control airflow The plate is machined so as form passages for fuel and or airflow The plate is machined so as to form passages for airflow The orifice may be a circular orifice or it may be a free-formed orifice eg. Including but not limited to Square or Rectangular or elliptical or oval or other geometrical shape. The shape of the entrance of airflow to the orifice may be formed so as to promote airflow.

There are many common designs for this purpose. The external shape of the plate may be as illustrated or any other geometrical shape suitable for an intended purpose.

REFERRING TO DRAWING SEVEN.

Shown is plan and side and end views of a liquid distribution tube. Shown at is the fuel inlet to the distribution tube. A row of holes for fuel distribution and mixture control across the venturi is labelled The points marked represent the approximate points where the walls of the venturi come into close proximity of the liquid distribution tube.

The passages marked are alternative methods of additional jetting control as detailed in claim 21. The internal bore of the tube is restrictive to high flow rates that are achieved at high engine fuel demand periods. The restriction may be set so that the fuel to air ratio delivered to the engine is leaner as the flow increases beyond a predetermined value. The fuel mixture strength will therefore be determined by the number and area and position of the multiple holes at lower flow levels than when the bore restriction becomes significant.

Claims (16)

1. A carburettor comprising a chassis upon to which is attached a removable plate containing a main air flow aperture and where the main percentage of mass of fuel supply required by the engine at high load is regulated by means of a liquid distribution tube containing a multiplicity of holes of less than 1mm diameter and a hole depth of less than 1mm placed within the main airflow aperture controlling the amount of fuel flow at the point of interaction with the atmosphere of the venturi and without the use of the fuel being emulsified with air prior to entry to the liquid distribution tube or use of booster venturi or use of a flow control needle or use of a main jet located below the normal fuel level height of the carburettor.

2. A carburettor comprising a chassis upon to which is attached a ren ovable plate containing multiple main air flow apertures and where the main percentage of mass of fuel supply required by the engine at high load is regulated by means of a liquid distribution tube containing a multiplicity of holes of larger than 1mm diameter and a hole depth of larger than 1mm placed within each main airflow aperture controlling the amount of fuel flow at the point of interaction with the atmosphere of the venturi and without the use of the fuel being emulsified with air prior to entry to the liquid distribution tube or use of booster venturi or use of a flow control needle or use of a main jet located below the normal fuel level height of the carburettor.

3. A carburettor of claim 1 or claim 2 where a main jet is located within the liquid distribution tube

4. A carburettor of claim 1 or claim 2 where the internal bore diameter of the liquid distribution tube is sized so that the fuel flow is further restricted beyond the restriction effect of the design of the said multiplicity of holes of claim 1 or claim 2. A carburettor of claim 1 or claim 2 where the entire mass of fuel supply required by the engine is regulated by the liquid distribution tube.

6. A carburettor of claim 1 or claim 2 where there is a multiplicity of plates to control fuel regulation and or air control combined with the removable plate of claim 1.

7. A carburettor where the said removable plate contains other jets and or devices and or passages for liquid control functions that supply the lower mass of fuel necessary for engine operation at low loads and slow speed that may have orifice diameters and or depths of less or greater than 1mm.

8. A carburettor where the fuel is supplied to the metering systems by direct connection to a mechanically pressure regulated system.

9. A carburettor of any of the claims from 1 to 20 where the fuel is supplied to the metering systems by direct connection to a mechanically pressure regulated system. A carburettor of any of the claims from 1 to 20 where the fuel is supplied to the metering systems from a computer regulated mass flow rate system.

11. A carburettor of any of the claims from 1 to 20 using any type of mixture controlling device that is held and or sealed by sandwiching between 2 surfaces.

12. A carburettor of any of the claims from 1 to 20 where the liquid distribution tube is removable from the plate.

13. A carburettor of any of the claims from 1 to 20 where the liquid distribution tube is held and or sealed by sandwiching between 2 surfaces.

14. A carburettor of any of the claims from 1 to 20 where the said liquid distribution tube of claims 16 to claim 18 is contained within a conventional booster venturi located within the main airflow orifice. A carburettor comprising a chassis upon to which is attached a removable plate or multiple plates containing a main airflow aperture and the main percentage of mass of fuel regulating device.

16. A carburettor comprising a chassis upon to which is attached a removable plate that is above the normal fuel level height containing a main air flow aperture and where the main percentage of mass of fuel supply required by the engine at high load is regulated by means of a liquid distribution tube containing a multiplicity of holes of less than 1mm diameter and a hole depth of less than 1mm placed within the main airflow aperture controlling the amount of fuel flow at the point of interaction with the atmosphere of the venturi and without the use of the fuel being emulsified with air prior to entry to the liquid distribution tube or use of booster venturi or use of a flow control needle or use of a main jet located below the normal fuel level height of the carburettor substantially as herein described with reference to the accompanying drawing #8.

17. A liquid distribution tube which solely controls the ratio of liquid flow due to a pressure differential by a multiplicity of holes between the range of.001" and .040" diameter that are arranged across the diameter of an air flowing orifice and where the liquid flow hole depth is less than .040" thereby controlling the amount of liquid flow at the point of interaction with the atmosphere of the venturi so formed and without the use of the liquid being emulsified with air or use of a flow control needle.

18. A liquid distribution tube which solely controls the ratio of liquid flow into an air flow orifice in response to a pressure differential by a multiplicity of holes arranged equidistant across the diameter of an air flowing orifice between the range of.001" and .040" diameter and where the liquid flow hole depth is less than 1mm and the internal bore of the said liquid distribution tube is sufficiently restrictive to reduce the ratio of fuel supplied to the engine as the air flow velocity increases thereby controlling the amount of liquid flow at the point of interaction with the atmosphere of the venturi and the internal bore of the said liquid distribution tube.

19. A liquid distribution tube which solely controls the ratio of liquid flow into an air flow orifice by response to a pressure differential in a singular and or multiplicity of slots arranged substantially across the diameter of an air flowing orifice and where the liquid flow slot depth is less than 1mm thereby controlling the amount of liquid flow at the point of interaction with the atmosphere of the venturi and the internal bore of the said liquid distribution tube. A carburettor substantially as herein described with reference to the accompanying drawing #8.