ENGINE MODIFIER

Abstract: Conditioning of petrol - based fuel prior to consumption is effected by storing a bulk quantity in a pressure vessel (13) and continuously extracting and returning a portion of that bulk quantity via a treatment conduit (18) which is heated along part of its length (19). The pressure vessel (13) is essentially unheated. Conditioned fuel is expelled from the pressure vessel (13) for consumption via a control valve (16), the pressure arising from the circulation and the condensation of heated vapours occurring within the vessel (13) from the fuel returning from the treatment conduit (18).

Description: ENGINE MODIFIER This invention relates to the conditioning of petrol- based fuel prior to consumption by a fuel-consumption unit. Conditioning of petrol-based fuels prior to consumption by a fuel-consumption unit is already known but the systems involved are usually very specialised and deal with minute quantities of fuel usually in metered quantities. One example of such a system is to be found in U.K. Patent Specification No. 1507975. Petrol-based fuels are light hydrocarbon liquids characterised by being highly inflammable and readily vaporisable eg at temperatures above 70°C but not explosive when heated and their handling characteristics are substantially different from other fuels, for example paraffin and diesel oil. It is an object of the present invention to provide a new and improved form of system and method for conditioning petrol-based fuels prior to consumption by a fuel- consumption unit. According to a first aspect the present invention provides a system for conditioning petrol-based fuel prior to consumption by a fuel-consumption unit, which system comprises : an unheated pressure vessel having a closable inlet for enabling liquid fuel in bulk to be delivered to the vessel, and an outlet with a control valve for delivering controlled quantities of conditioned fuel to the fuel- consumption unit; a treatment conduit which is close-coupled to the vessel, extends externally of the vessel, and is connected at both ends to the interior of the vessel; and means for heating a zone of the conduit; the arrangement being such that prior to the heating means being effective the volume of liquid fuel stored within the vessel is within a pre-determined range such that the vessel is only part filled with fuel in liquid form to a level which is below said outlet, part of said conduit is filled with fuel in liquid form, said conduit part including said conduit zone and the remainder of the conduit is vapour or gas filled, and the interface between the liquid and vapour phases within the vessel is of large surface area; whereby when the heating means is rendered effective the liquid fuel in said conduit part expands and establishes a continuous circulation of expanded liquid and vapour phases through the vessel and the conduit with substantially instantaneous condensation of heated vapours occurring at said interface surface area where the stored volume of liquid is relatively cold, the conditioned fuel being delivered through said outlet when the control valve is opened and being a portion of said circulation expelled due to pressure in the vessel arising from said circulation and said condensation. According to a second aspect the present invention provides a method of conditioning petrol-based fuel prior to consumption by a fuel-consumption unit, comprising the steps of : delivering an initial bulk volume of liquid fuel to the interior of a pressure vessel such that the vessel is only initially part filled with fuel in liquid form; extracting a proportion of the liquid from the vessel,* heating the extracted proportion to achieve at least partial expansion and vaporisation thereof; circulating at least some of the heated and vaporised extracted proportion back into the pressure vessel whilst maintaining the pressure vessel essentially unheated; substantially instantaneously condensing at least some of the extracted portion in the pressure vessel and continuously continuing the aforesaid heating and circulatory steps to establish a pressure within the vessel with the co-existence therein of expanded liquid and vapour phases of the fuel; and delivering a controlled quantity of conditioned fuel from the vessel to the fuel consumption unit, the conditioned fuel being essentially a portion of the vapour phase of the fuel in the circulation and the delivery being provided by the pressure within the vessel . It is believed that the system conditions the fuel by expanding the liquid and vapour phases to an extent dependent upon the heat supplied by the heating means and the substantially instantaneous condensation which occurs at the interface surface area, as a result of which the conditioned fuel delivered to the fuel-consumption unit is of enhanced combustion efficiency and is capable of being combusted essentially in its entirety with minimal production of toxic by-products. By way of example, when applied to a static IC engine driving a fixed load carbon monoxide emissions were reduced dramatically utilising the invention, in comparison with the same engine and load being operated by the same (unconditioned) fuel delivered through a conventional carburettor. It is to be understood that the present invention conditions bulk quantities of petrol-based liquors, of the order of litres, as distinct from minute or droplet quantities. The pressure vessel may take any convenient shape which relative to the bore of the treatment conduit provides the required magnitude of interface surface area to achieve the required substantially instantaneous condensation. The interface surface area is, of course, essentially a horizontal surface area. For example the vessel may be elongate with either a circular or elliptical cross-section; it may be rectilinear, spherical or ovoid. Typically it requires to contain relative pressures in the range 2-20 psi or even up to 3000 psi, to withstand fuel from the conduit arriving at temperatures of from ambient up to about 250°C or even to superheated temperatures, for most consumption units and yet to remain essentially unheated. The outlet is essentially a port or pipe located in an upper part of the pressure vessel above the initial level of liquid therein. The control valve may take any convenient form which permits a pressure tight seal to be established during initial heating of the system and the attendant pressure build-up in the vessel. Thereafter, when the valve is opened, it requires to regulate the quantity of conditioned fuel expelled from the vessel. The treatment conduit may take any one of a wide variety of forms provided it is suitably connected at each end to the vessel. For example, one end may connect below the initial level of liquid in the vessel and the other end is connected at or above the initial level of liquid so that only part of the conduit is itself completely filled with the liquid, this part being heated. In this case the conduit requires to be of a bore size larger than a minimum size at which circulation blockage occurs within the conduit. The cross-sectional shape of the conduit may be any convenient shape which is substantially continuous and free of significant discontinuities. The conduit requires to withstand the same pressure range as the vessel and essentially the same temperature range but that zone of the conduit to which heat is applied is subjected to an elevated temperature. Alternatively both ends of the conduit connect at the initial liquid level of liquid in the vessel and the conduit lies in the horizontal plane such that the entire length of the conduit is part filled with liquid. In this case the bore size of the conduit requires to be larger than the aforesaid minimum size and the initial liquid level requires to be maintained throughout consumption of fuel by the controlled addition of fresh unconditioned fuel. It will be appreciated from the foregoing chau the treatment conduit may lie in the horizontal plane or in the vertical plane or in any intermediate plane. It may also have parts which lie in any combination of these planes. The heating means may take any form and may provide heat to the zone of the conduit either directly or indirectly. For example, the heating means may be an electrical heater or a burner having a flame directly incident on the conduit. The burner may be powered with fuel such as a small portion of the conditioned fuel expelled from the pressure vessel. Alternatively the heating means may be a heat exchanger carrying a heated fluid in contact with the conduit. The heated fluid of the heat exchanger may be a liquid such as water or a gas such as the exhaust gas from the fuel-consumption unit. Any combination of the aforesaid or other heating arrangements may be utilised either simultaneously or consecutively to provide any desired amount of heat to the conduit. The heating means is effective upon the specified zone of the conduit which is a portion of the conduit containing fuel in liquid form in the first instance. Depending upon the nature of the conduit as previously discussed the zone may therefore be of any length, from only a small proportion of the total length of the conduit to a very large proportion of the total length of the conduit. The zone of the conduit may be entirely filled with liquid or may only be partly filled with liquid. The total length of the conduit however requires to be limited in relation to the size of the vessel so that the two are ' close- coupled' by which is meant that the condensing function undertaken in the vessel is confined to the vessel by virtue of the conduit not being of excess length which would lead to cooling and condensing of the vapours in the conduit . The petrol-based fuel may also take any form which has a liquid phase at ambient temperatures. The term "liquid" is intended to encompass a very wide range of viscosities provided that when the fuel is initially delivered in bulk to the pressure vessel it is capable of flowing within a suitably short time to establish the required initial liquid levels. Clearly this is achieved when the fuel is in the form of petrol. The fuel-consumption unit may take a wide variety of forms. For example, it may be an internal combustion engine in which case the conditioned fuel from the system is fed essentially directly to the engine as is a supply of combustion air. The latter need not be regulated in volume and engine speed is controlled by the control valve of the system. If the air intake to the engine is regulated in volume the regulator is preferably ganged to the system control valve, for example by a mechanical linkage. Alternatively the fuel-consumption unit may be a furnace. The furnace may for example be a central- heating furnace. An embodiment of the present invention will now be described by way of example with reference to the accompanying drawing, in which: Fig. 1 schematically illustrates a first view of the system; Fig. 2 schematically illustrates a second view of the system; and Fig. 3 illustrates a modification to the Fig 1 system. The drawing shows a system 10 for conditioning petrol- based fuel (which may be petrol) prior to consumption by a fuel-consumption unit 11 (which may be in the form of an internal combustion engine) . Fuel to be treated is delivered to the system 10 from a source 12 (which may be a bulk tank) and prior to operation of the system is held, in bulk, in an unheated pressure vessel 13 which has a closable inlet 14, and an outlet 15 provided with a control valve 16 for delivering controlled quantities of conditioned fuel to the unit 11. A treatment conduit 18 extends externally of the vessel 13 but is close-coupled thereto and is connected at each end to the interior of the vessel 13. Conduit 18 is of substantially uniform bore and includes along its length a zone 19 which is associated with a heat source 20. When unit 11 is an IC engine, source 20 is conveniently a heat exchanger fed with the exhaust gases of the engine, for example delivered at various ports 20A and exiting from port 20B. In the embodiment inlet 14 provides a level control for the fuel initially delivered to the vessel 13 and achieves a liquid level 22 such that the vessel 13 is only part filled with fuel in liquid form, this being below the level of the outlet 15 and, in this case, half flooding the conduit 18 throughout its length. Conduit zone 19 is therefore part filled with liquid fuel. Conduit 18 is essentially horizontal as shown in Fig. 2. In the absence of applied heat from source 20 there is no emission of fuel from the vessel 13. However when heat is applied the fuels in the zone 19 expand and very rapidly establish a continuous circulation of liquid and vapour phases travelling in a circuit through the conduit 18 and the vessel 13. The incoming heated circulation to the vessel 13 is essentially in vapour form and at elevated temperature whereas in the vessel 13 the body of liquid fuel is comparatively cold and its interface surface area with the co-existing vapour phase in the vessel 13 is comparatively large. Thus substantially instantaneous condensation of at least some of the incoming circulation occurs at the interface. However, the circulation is continuous and entrains the liquid fuel within the vessel 13 below the interface surface and at a location remote from the incoming heated circulation to the vessel so that essentially all of the fuel is expanded and in co-existing liquid and vapour phases travelling in the circulation. The net effect of the continuous circulation and the condensation occurring within the vessel 13 is to establish a positive pressure within vessel 13 and when valve 16 is opened, in a regulatory manner, a portion of the circulation is expelled due to the pressure in the vessel 13 and is delivered to the unit 11 to be consumed in the pressure of air which may be delivered thereto in any convenient manner and without requiring regulation. The resulting combustion within the unit 11 is essentially achieved completely and with minimal production of toxic by-products . When the initial charge within vessel 13 has been more or less completely delivered to the consumption unit 11 a further charge of fuel may be delivered to the vessel 13 from the fuel source 12 which for this purpose requires to deliver at a pressure greater than that prevailing in the vessel 13. It will also be understood that if the heat source 20 is a heat exchanger utilising heat from the exhaust gases of the consumption unit 11, there would need to be a start-up facility for unit 11, for example using a conventional fuel supply system in order to generate initial heat for initiating the conditioning of the fuel in the vessel 13. This start-up facility could be shut down on a manual or on an automatic basis after a period of time to permit control valve 16 to be operated thereafter for delivery of the conditioned fuel directly to the consumption unit 11. Alternatively, of course, an alternative heat source 20 could be used. By way of example only, the vessel 13 may be about 9 inches in length and having a diameter of about 3 inches as a result of which the interface surface area of the liquid phase in the vessel is about 27 square inches. The conduit 18 may have a diameter of about 1 inch throughout its length. The length of conduit 18 is about 15 inches. In the Fig 1 embodiment the two ends of the conduit 18 connect with the vessel 13 at the same level (but not directly opposite) whereas in the Fig 3 embodiment one end of the conduit 18 connects to the top of vessel 13 and the other end connects to the bottom of the vessel 13. The Fig 3 embodiment provides improved controllability of the fuel consumption unit 11.

Claims: Claims 1 A system for conditioning petrol-based fuel prior to consumption by a fuel-consumption unit, which system comprises : an unheated pressure vessel having a closable inlet for enabling liquid fuel in bulk to be delivered to the vessel, and an outlet with a control valve for delivering controlled quantities of conditioned fuel to the fuel- consumption unit; a treatment conduit which is close-coupled to the vessel, extends externally of the vessel, and is connected at both ends to the interior of the vessel; and means for heating a zone of the conduit; the arrangement being such that prior to the heating means being effective the volume of liquid fuel stored within the vessel is within a pre-determined range such that the vessel is only part filled with fuel in liquid form to a level which is below said outlet, part of said conduit is filled with fuel in liquid form, said conduit part including said conduit zone and the remainder of the conduit is vapour or gas filled, and the interface between the liquid and vapour phases within the vessel is of large surface area,* whereby when the heating means is rendered effective the liquid fuel in said conduit part expands and establishes a continuous circulation of expanded liquid and vapour phases through the vessel and the conduit with substantially instantaneous condensation of heated vapours occurring at said interface surface area where the stored volume of liquid is relatively cold, the conditioned fuel being delivered through said outlet when the control valve is opened and being a portion of εaid circulation expelled due to pressure in the vessel arising from said circulation and said condensation. 2 A system as claimed in Claim 1, wherein the two ends of the treatment conduit connect to the pressure vessel at different levels with respect to the interface. 3 A system as claimed in either preceding claim, wherein the treatment conduit is substantially free of internal discontinuity along its length. 4 A method of conditioning petrol-based fuel prior to consumption by a fuel-consumption unit, comprising the steps of : delivering an initial bulk volume of liquid fuel to the interior of a pressure vessel such that the vessel is only initially part filled with fuel in liquid form; extracting a proportion of the liquid from the vessel; heating the extracted proportion to achieve at least partial expansion and vaporisation thereof; circulating at least some of the heated and vaporised extracted proportion back into the pressure vessel whilst maintaining the pressure vessel essentially unheated; substantially instantaneously condensing at least some of the extracted portion in the pressure vessel and continuously continuing the aforesaid heating and circulatory steps to establish a pressure within the vessel with the co-existence therein of expanded liquid and vapour phases of the fuel; and delivering a controlled quantity of conditioned fuel from the vessel to the fuel consumption unit, the conditioned fuel being essentially a portion of the vapour phase of the fuel in the circulation and the delivery being provided by the pressure within the vessel. 5 A method as claimed in Claim 4, wherein the total length of the path along which the extracted portion travels to be heated is limited in relation to the size of the vessel so that the condensing function is confined to the vessel . 6 A method as claimed in Claim 4 or Claim 5, wherein the petrol-based fuel is petrol.

Inventors: LONGMORE EDMUND, TEMPLETON ANDREW, LONGMORE, EDMUND, TEMPLETON, ANDREW
Applicants: LONGMORE EDMUND, MULTIPLIERS LTD, TEMPLETON ANDREW, LONGMORE, EDMUND, MULTIPLIERS LIMITED, TEMPLETON, ANDREW
Application year: 1996
Main classification: F02M31
IPC codes: F02M31