Field of the Invention

The present invention relates to the enrichment of hydrocarbon fuels, particularly for use with internal combustion engines. The present invention provides methods and systems for the enrichment of hydrocarbon fuels. The present invention further provides an internal combustion engine having such a system, and a vehicle having such an internal combustion engine.

Background

Current internal combustion engine fuel systems utilise a petrol/air or a diesel/air mixture which is subsequently ignited in the combustion chamber. A large and varied number of fuel systems for use on internal combustion engines exist. A typical example is that of a petrol fuelled system that will utilise a carburettor in which the liquid fuel (petrol) is vaporised via a venturi through which atmospheric air is fed. The fuel vapour/air mixture is subsequently drawn into the intake manifold of the engine and finally into the cylinders where it is ignited by a spark. Engines running a diesel/air mixture use a fuel injection system whereby the fuel is injected into the combustion chamber under high pressure; this does not require the use of a spark for ignition.

Hydrogen generators, utilising electrolysis to break down water into hydrogen and oxygen, have been in existence for many years. The electrolysis works by passing an electric current though water (H ₂ 0) which causes the water to revert to its' original constituent gases. At the negatively charged cathode, a reduction reaction takes place, with electrons (e-) from the cathode being given to hydrogen cations (positively charged ions) to form hydrogen gas:

Cathode (reduction): 2 H+(aq) + 2e-→ H ₂ (g)

At the positively charged anode, an oxidation reaction occurs, generating oxygen gas and giving electrons to the cathode to complete the circuit:

Anode (oxidation): 2 H ₂ 0(l)→ 02(g) + 4 H+(aq) + 4e- Electrolytic hydrogen generators have been used for enhancing the fuel efficiency of internal com bustion engines. Such generators are sometimes termed HHO generators. Typically, hydrogen and oxygen produced in an electrolytic cell is fed into the air intake manifold of an internal combustion engine, which has been found to increase the fuel efficiency of the internal combustion engines.

The present invention aims to improve or provide an alternative to the devices of the prior art.

Summary of the Invention

The present invention provides, in a first aspect, a process for enrich ing a hydrocarbon fuel for use in an internal combustion engine, the process comprising:

(i) generating hydrogen gas and oxygen gas;

(ii) contacting a liquid hydrocarbon fuel with the hydrogen gas and oxygen gas under a pressure greater than atmospheric pressure such that at least some of the hydrogen gas and at least some of the oxygen gas is introduced into the hydrocarbon fuel to produce an enriched hydrocarbon fuel.

Introducing the at least some of the hydrogen gas and at least some of the oxygen gas may comprises dissolving at least some of the hydrogen gas and at least some of the oxygen gas into the hydrocarbon fuel.

Contacting the liquid hydrocarbon fuel with the first gas stream may comprise contacting the liquid hydrocarbon fuel with the first gas stream at a pressure of 1 .1 bar or above, or at a pressure of 2 bar or above.

The pressure of 1.1 bar or 2 bar referred to is an absolute pressure of 1 .1 bar or 2 bar, that is a pressure of 0.1 bar or 1 bar in excess of atmospheric pressure (also referred to as a pressure of "0.1 bar gauge" or "1 bar gauge").

The enriched hydrocarbon fuel may be delivered to an internal combustion engine.

The enriched hydrocarbon fuel may be heated to a temperature of at least 50 °C, and then passed to the internal combustion engine. The enriched hydrocarbon fuel may be subjected to a magnetic field at the same time as it is heated to a temperature of at least 50 °C.

Generating the hydrogen gas and oxygen gas may comprise generating a first gas stream containing hydrogen gas and oxygen gas. Generating a single gas stream that contains both hydrogen and oxygen can simplify the process, although in principle a gas stream containing hydrogen gas and a separate gas stream containing oxygen gas could be generated.

The process may comprise generating the first gas stream in an electrolytic process from water in a first electrolytic cell.

The process may further comprise:

generating a second gas stream containing oxygen and optionally hydrogen; and

delivering the second gas stream to the internal combustion engine, the second gas stream contacting the enriched hyd rocarbon fuel in the internal combustion engine.

This is a convenient way of generating hydrogen gas and oxygen gas as they are required. However the invention is not limited to this and the process may, as an alternative, involve obtaining the hydrogen gas for the first gas stream from a store of hydrogen and/or and involve obtaining the oxygen gas for the first gas stream from a store of oxygen.

The process may comprise generating the second gas stream in an electrolytic process from water in a second electrolytic cell. Alternatively, the second gas stream may be generated by separating a fuel/gas mixture.

The internal combustion engine may comprise an air inlet and a fuel inlet for introduction of the fuel into the engine for contacting the fuel with the air from the air inlet, and the enriched hydrocarbon fuel may be introduced into the engine through the fuel inlet. The second gas stream (if present) may be introduced into the engine through the air inlet of the engine. Contacting the first gas stream with the hydrocarbon fuel may produce the enriched hydrocarbon fuel and a gaseous mixture, and the process may further comprise separating the enriched hydrocarbon fuel and the gaseous mixture. As noted, the gaseous mixture obtained in this was may be used as the second gas stream.

The process may optionally comprises delivering the enriched hydrocarbon fuel to the internal combustion engine at a fuel inlet of the internal combustion engine; and/or delivering the gaseous mixture to the internal combustion engine at an air inlet of the internal combustion engine.

When the internal combustion engine is running, unused hydrocarbon fuel from the internal combustion engine may be circulated such that, after it has left the internal combustion engine, it is contacted with the first gas stream containing hydrogen such that at least some of the hydrogen gas is introduced into the hydrocarbon fuel to produce an enriched hydrocarbon fuel. For example, if the process of contacting the hydrocarbon fuel with the first gas stream is carried out in an enrichment chamber, un used fuel may be introd uced into the enrich ment chamber. The enriched hydrocarbon fuel may then be passed back to the internal combustion engine.

The enriched hydrocarbon fuel may be delivered to an internal combustion engine at a vol umetric rate of delivery V _e (i n L/mi n); the hyd rocarbon fuel is a liq u id hydrocarbon fuel and a gas stream containing hydrogen is contacted or passed through the hydrocarbon fuel to produce the enriched hydrocarbon fuel, such that the hydrogen in the gas stream contacts or passes through the hydrocarbon fuel at volumetric rate V _f (in L/min), and the ratio of V _e :V _f is in the range 1 :1 to 1 :15.

The ratio V _e :V _f may be in the range 1 :4 to 1 :12.

The present invention provides, in a second aspect, a system for carrying out a process for enriching a hydrocarbon fuel for use in an internal combustion engine, the device adapted to carrying out a process comprising:

(i) generating hydrogen gas and oxygen gas;

(ii) contacting a liquid hydrocarbon fuel with the hydrogen gas and oxygen gas under a pressure greater than atmospheric pressure such that at least some of the hydrogen gas and at least some of the oxygen gas is introduced into the hydrocarbon fuel to produce an enriched hydrocarbon fuel. The at least some of the hydrogen gas and at least some of the oxygen gas may be dissolved into the hydrocarbon fuel.

The system may comprise:

a production unit for producing a first gas stream containing hydrogen and oxygen,

an enriching unit for contacting the hydrocarbon fuel and the first gas stream such that at least some of the hydrogen gas and some of the oxygen gas is introduced into the hydrocarbon fuel to produce the enriched hydrocarbon fuel, the hydrogen production unit being in fluid connection with the enriching unit such that the first gas stream is passed to the enriching unit, the enriching unit having an inlet for the hydrocarbon fuel, and

an outlet for the enriched hydrocarbon fuel.

The production unit may comprise a generator for generating hydrogen gas and oxygen gas, and a receiver for storing the hydrogen gas and oxygen gas at a pressure above atmospheric pressure, the receiver being in fluid connection with the enriching unit.

The production unit may comprise a first electrolytic cell for generating hydrogen gas and oxygen gas in an electrolytic process from water.

The receiver for storing the hydrogen gas and oxygen gas may further store, in use, an electrolyte for the first electrolytic cell.

The system may comprise a heater in fluid connection with the outlet for the enriched hydrocarbon fuel in the enriching unit, the heater capable of heating the hydrocarbon fuel to a temperature of at least 50 °C.

The heater further may comprise a means for subjecting the enriched hydrocarbon fuel within the heater to a magnetic field.

The system may be adapted to generate a second gas stream containing oxygen gas and optionally hydrogen gas. The present invention provides, in a third aspect, an internal combustion engine having a system of the second aspect attached thereto, the system having a conduit for delivery of the enriched hydrocarbon fuel from the enriching unit to a fuel intake of the internal combustion engine.

Optionally, any excess hydrogen gas and oxygen gas (ie, hydrogen gas and oxygen gas that is not introduced into the fuel) may be delivered to an air intake of the engine.

If the system generates a second gas stream, a conduit for delivery of the second gas stream may be in fluid connection with an air intake of the internal combustion engine.

The engine may be adapted such that, in use, unused hydrocarbon fuel from the internal combustion engine is circulated such that, after it has left the internal combustion engine, it is contacted with the gas stream containing hydrogen such that at least some of the hydrogen gas is introduced into the hydrocarbon fuel to produce an enriched hydrocarbon fuel. For example, if the system comprises an enrichment un it, un used fuel may be introduced into the enrich ment un it. The enriched hydrocarbon fuel may then be passed back to the internal combustion engine.

The present invention provides, in a fourth aspect, a vehicle having an internal combustion engine of the third aspect.

In recent times one of the major concerns related to internal combustion engines has been their emissions, both NOx (oxides of nitrogen) and COx (carbon monoxide and carbon dioxide). The device of the present invention can be used with any hydrocarbon fuel-based combustion engine to reduce the NOx output and the COx "footprint". This is ach ieved by addition of the hyd rogen and oxygen to the combustion process to give far more efficient combustion characteristics due to the high speed/high temperature hydrogen combustion which improves the vehicle economy; the NOx output is reduced because some of the nitrogen containing air is displaced from the hydrocarbon fuel and also because of the contained combustion volume. This also reduces the overall engine temperature since heat transfer from the combustion process is minimised. In at least some circumstances, the addition of the hydrogen to the hydrocarbon fuel has been found to im prove the combustion of the fuel to such a degree that particulate output is dramatically reduced (in some circumstances, almost to zero on diesel engines). In addition the process has been found to clean carbon deposits from engines that have built up over time, thus reducing the overall friction of the engine (and hence further improving the efficiency). Finally, the fuel/oxidiser (e.g. air) mixture can be made much leaner due to the addition of the hydrogen which has a much higher equivalent octane rating than petrol, thus increasing the COx:fuel ratio (and hence reducing the carbon footprint).

Whilst hydrogen/oxygen gas generators that can be used with internal combustion engines have been available to buy for a few years the nature of use has been relatively simple i.e. mixing of the produced gas with the fuel and air in the turbo manifold. The process of the present invention greatly enhances the way the gas is used to give optimised performance, which, in one embodiment, is by introducing the gases into the fuel under compression in a pressurisation unit. This displaces unwanted dissolved gases in the fuel such as nitrogen and increases the octane rating of the fuel.

Brief Description of the Drawings

Preferred embodiments of the present invention will be described with reference to the accompanying drawings in which:

Figure 1 shows a diagrammatic block view of an embodiment of the device of the present invention attached to an internal combustion engine.

Figure 2 shows a diagram of an embodiment of the Fuel Enhancement Chamber (an embodiment of the device of the present invention) showing its principle parts.

Figure 3 shows a diagram of a purification unit comprising a gas scrubbing device.

Figure 4 shows a diagram of a purification unit comprising a molecular sieve drying unit. Figure 5 shows a diagram of a further embodiment of the Fuel Enhancement Chamber, which differs from that of Figure 2 in that the piston is driven by a screw mechanism, rather than a solenoid.

Figure 6 is a diagrammatic block view of another embodiment of the device of the present invention attached to an internal combustion engine.

Figure 7 shows a possible electrical control diagram for the embodiment of figure 6. Figure 8 is a block flow diagram of a method according to one embodiment of the invention.

These drawings are referred to in the detailed description which follows.

Detailed Description of the Invention

Figure 1 shows a block flow diagram illustrating an embodiment of the present invention. Figure 1 illustrates the invention in the context of an internal combustion engine of a vehicle, but the invention is not so limited and may be applied to any internal combustion unit.

A gas stream containing hydrogen and oxygen is generated, in this embodiment by electrolysis of water in a first electrolytic cell 1 which may be any suitable electrolytic cell for the generation of hydrogen gas and oxygen gas. The first electrolytic cell 1 may be any suitable electrolytic cell but advantageously is a sealed electrolytic cell (known generally as a "dry cell").

The gas stream produced by the first cell 1 preferably contains at least 10 % by volume of hydrogen gas, optionally at least 20 % by volume, optionally at least 30 % by volume, optionally at least 40 % by volume, optionally at least 50 % by volume, optionally at least 60 % by volume hydrogen. In a gas stream produced from the electrolysis of water, the gas stream may comprise about 66 % by volume hydrogen.

The gas stream produced by the first cell 1 further comprises oxygen. The gas stream containing hydrogen may contain at least 1 0 % by volume of oxygen , optionally at least 20 % by volume of oxygen, optionally at least 30 % by volume of oxygen. In a gas stream produced from the electrolysis of water, the gas stream may comprise about 33 % by volume oxygen. The contacting of the gas stream with the hydrocarbon fuel (described below), if it comprises a liquid hydrocarbon fuel, may involve dissolving at least some of the oxygen into the liquid hydrocarbon fuel.

The gas stream from the electrolytic cell 1 is passed to a fuel enrichment device (6A; otherwise termed a Fuel enhancement Chamber) which also receives a hydrocarbon fuel from the vehicle's fuel tank 1 3 via the vehicle's fuel line 14. In the fuel enhancement chamber 6a at least some of the hydrogen gas and at least some of the oxygen gas in the gas stream are introduced into the hydrocarbon fuel, as described in more detail below, to produce an enriched hydrocarbon fuel. The enriched hydrocarbon fuel is introduced into the engine 9 of the vehicle, for example via the fuel injector pump 8.

The hydrocarbon fuel may comprise, for example, petroleum or diesel . The hydrocarbon fuel is described in more detail below. In the present application, if hydrogen and optionally oxygen is/are contacted with and optionally dissolved into the hydrocarbon fuel, preferably there is no change in the chemical structure of the hydrocarbon species within the fuel. For example, preferably, the hydrocarbon species in the hydrocarbon fuel are not chemically reacted with the hydrogen or oxygen during the contacting of the hydrogen and oxygen with the hydrocarbon fuel.

The enriched hydrocarbon fuel optionally passes through a heat treatment 7, which may also involve application of a magnetic field, before being introduced into the engine 9. This heat treatment is described in more detail below.

The enriched hydrocarbon fuel may be delivered to the internal combustion engine at a suitable volumetric rate (typically measured in L/min), which will depend on the type of the engine and the mechanical equipment to which it may be attached, such as a vehicle in this embodiment. This may, for example on some vehicles, be in the region of 0.05 L/min to 1 L/min, optionally in the region of 0.1 L/min to 0.5 L/min.

Before reaching the fuel enhancement chamber 6a the gas stream optionally passes through two purification units in sequence. The first purification unit 3 comprises a plurality of chambers containing deionised water, the one or more chambers being adapted for passing the gas stream containing hydrogen through the water. The first purification unit 3, which may also be termed gas scrubbing devices, is shown in more detail in Figure 3. All of the walls of the first purification units are fabricated from 316 stainless steel. The gas stream containing hydrogen bubbles through the deionised water in each compartment sequentially, and the caustic species in the gas stream that may be present from the electrolysis process, are dissolved into the water, producing a purified gas stream. This purification step is desirable since a certain amount of caustic vapour is carried over from the electrolysis process. This vapour, if not treated, has been found to cause severe problems within aluminium cylinder heads, parts etc.

The final step in purification of the gas is to pass it through a second purification unit that functions as a desiccator to dry the gas before introduction of the gas into the air intake or the Fuel Enhancement Chamber. The desiccator may for example be a molecular sieve trap as shown in cross-section in Figure 4. The molecular sieve trap comprises a chamber in the form of a cylinder, having particles of a molecular sieve disposed between two gas permeable circular sintered metal disks. A void is present between the end walls of the cylinder and the two circular sintered metal disks. Each end wall of the cylinder comprises an aperture for allowing a gas stream to pass into or out of the cylinder as appropriate. The drying of the gas stream comprising hydrogen has been found to produce a smoother, less "explosive" combustion when the enriched hydrocarbon fuel is combusted in an internal combustion engine. The molecular sieve traps can be sized dependant on gas flow rates and expected water content and will typically be packed with molecular sieve type 4A or 5A.

The embodiment of figure 1 optionally comprises a second electrolytic cell 2 for generating a second gas stream that contains oxygen and optionally hydrogen. The second gas stream passes through two purification units 10, 1 1 in sequence. The second electrolytic cell 2 and its associated two purification units 10, 1 1 correspond to the first electrolytic cell 1 and its associated two purification units 3, 4 and their description will not be repeated. The second gas stream is delivered to the internal combustion engine 9, and contacts the enriched hydrocarbon fuel in the internal combustion engine. Where both the first and second electrolytic cells are provided, the invention therefore involves contacting the gas stream from the first electrolytic cell 1 with the hydrocarbon fuel (in the fuel enhancement chamber 6A) such that at least some of the hydrogen gas and at least some of the oxygen gas is introduced into the hydrocarbon fuel to produce an enriched hydrocarbon fuel and then delivering the enriched hydrocarbon fuel to an internal combustion engine, and delivering the gas stream from the second electrolytic cell 2 to the internal combustion engine, the second gas stream contacting the enriched hydrocarbon fuel in the internal combustion engine. The enriched hydrocarbon fuel may be delivered to a fuel inlet of the internal combustion engine, and the gas stream from the second electrolytic cell 2 may be delivered to an air inlet of the internal combustion engine.

The process of en rich ing the hydrocarbon fuel may involve contacting the hydrocarbon fuel with a gas stream containing the hydrogen gas and a gas stream containing the oxygen gas, such that at least some of the hydrogen gas and oxygen gas is introduced into the hydrocarbon fuel to produce the enriched hydrocarbon fuel. The gas stream containing the hydrogen gas and the gas stream containing the oxygen gas may be the same stream or different gas streams, preferably the same gas stream.

In an alternative embodiment, the process may involve providing gas containing hydrogen gas and optionally oxygen gas and passing the liquid hydrocarbon fuel through the gas stream containing hydrogen gas and optionally oxygen gas, such that at least some of the hydrogen and optionally oxygen is incorporated into the hydrocarbon fuel, which may involve for example, if the hydrocarbon fuel is a liquid hydrocarbon fuel, spraying the liquid hydrocarbon fuel into the gas containing the hydrogen gas and optionally oxygen gas.

Some feature of the embodiment of figure 1 will now be described in more detail.

According to the invention, the hydrogen gas and oxygen gas are contacted with the hydrocarbon fuel in the fuel enhancement chamber under a pressure greater than atmospheric pressure. For this application, the higher the working pressure in the fuel enhancement chamber the greater the amount of dissolved hydrogen and oxygen is present in the enriched fuel, leading to greater efficiency when the fuel is consumed in an internal combustion engine. However, it should be noted that higher pressures (typically pressures of greater than around 4 bar) could almost certainly not be achieved in an embodiment in which the pressure is derived from pressure generated in the production of the hydrogen and oxygen gas, but would need to be generated using some form of pressurising device (such as the pump of figure 2). Moreover, there are safety implications if high pressures are used. I n general, a pressure between about 1.1 bar and about 4 bar (ie, 0.1 bar to 3 bar in excess of atmospheric pressure) is preferred - any pressure above atmospheric will introduce more hydrogen and oxygen into the fuel, and a pressure of 4 bar is achievable without significant safety/cost implications. More preferably, a pressure in the range 2 - 4 bar absolute (that is 1 bar to 3 bar in excess of atmospheric pressure) may be used, as a pressure in this range provides good efficiency but without significant safety/cost implications.

The invention is not however restricted to a pressure within the range 1 .1 bar to 4 bar, or within the range 2 bar to 4 bar. In some applications, for example where the invention is for use with a large internal combustion engine (eg in a marine internal combustion engine) the costs involves in using a pressure greater than 4 bar may be outweighed by the increase in efficiency that would be obtained . As a further example, the hydrogen gas and oxygen gas may be contacted with the hydrocarbon fuel optionally at a pressure of about 1 .2 bar or more, optionally at a pressure of about 1.3 bar or more, optionally at a pressure of about 1 .4 bar or more, optionally at a pressure of about 1 .5 bar or more, optionally at a pressure of about 1 .7 bar or more, optionally at a pressure of about 2 bar or more, optionally at a pressure of about 3 bar or more, optionally at a pressure of about 4 bar or more, optionally at a pressure of about 5 bar or more, optionally at a pressure of about 6 bar or more, optionally at a pressure of about 8 bar or more, optionally at a pressure of about 10 bar or more, optionally at a pressure of about 15 bar or more, optionally at a pressure of about 20 bar or more, optionally at a pressure of about 25 bar or more, optionally at a pressure of about 30 bar or more. Optionally, the hydrogen gas and oxygen gas are contacted with the hydrocarbon fuel under a pressure of below about 10 bar, optionally below about 8 bar, optionally below about 7 bar, optionally below about 5 bar, and optionally in the range of 1 .5 bar to about 4 bar. As explained above, these pressures are absolute pressures, that is a pressure of 5 bar, for example, is a pressure of 5 bar absolute, which is 4 bar in excess of atmospheric pressure.

The contacting of the gas stream containing hydrogen and the hydrocarbon fuel may be carried out at ambient temperature, for example a temperature of at or above -10 °C, optionally from -10 °C to 30 °C. Optionally, the contacting of the gas stream and the hydrocarbon fuel may be carried out in the fuel enrichment unit at a temperature above the ambient temperature outside of the fuel enrichment unit. Optionally, the contacting of the gas stream and the hydrocarbon fuel may be carried out in the fuel enrichment unit at a temperature at or above 30 °C, optionally above 40 °C, optionally above 50 °C.

The gas stream containing hydrogen and oxygen may be contacted with the hydrocarbon fuel at a suitable rate such that such that at least some of the hydrogen gas and oxygen gas is introduced into the hydrocarbon fuel to produce an enriched hydrocarbon fuel. The gas stream containing hydrogen and oxygen may be passed through the hydrocarbon fuel, optionally diffused through the hydrocarbon fuel, to produce the enriched hydrocarbon fuel , wh ich is then passed to an internal combustion engine. I n a preferred embodiment, the ratio of 'volumetric rate of delivery of the enriched hydrocarbon fuel to the internal combustion engine (in L/min):volumetric rate of hydrogen in the gas stream containing hydrogen contacted or passed through the hydrocarbon fuel to produce the enriched hydrocarbon fuel (in L/min)' is 10:1 to 1 :50, preferably 1 :1 to 1 :15, more preferably 1 :4 to 1 :12.

In a preferred embodiment, the ratio of 'volumetric rate of delivery of the enriched hydrocarbon fuel to the internal combustion engine (in L/min):volumetric rate of total volume of gas stream containing hydrogen contacted or passed through the hydrocarbon fuel to produce the enriched hydrocarbon fuel (in L/min)' is 20:3 to 1 :75, preferably 3:2 to 1 :22.5, more preferably 1 :6 to 1 :18.

Typical cells suitable for use as the first electrolytic cell 1 and (if present) the second electrolytic cell 2 include a chamber comprising water, one or more electrodes C that can act as cathodes and one or more electrodes A that can act as anodes, the electrodes being in contact with the water. The cell may include a plurality of electrodes A and a plurality of electrodes C. The electrodes A and C may be in any suitable form, for example in elongated form, such as a cylinder, or in the form of a plate. The electrodes A and C may be arranged as a series of plates in an alternating manner, i.e. wherein, aside from the end plates in the series, each electrode A is disposed between two electrodes C, and each electrode C being disposed between two electrodes A, wherein adjacent electrodes have a non- conductive substrate, e.g. a non-conductive gasket, disposed between them. In a preferred embodiment, a conductive neutral substrate is disposed between an adjacent electrode A and an adjacent electrode C. A conductive neutral substrate is one which, when the cell is in operation, does not have an electric charge applied to it, unlike the electrodes A and C. The conductive neutral substrate preferably contacts the water in the cell . Optionally, if the cell comprises a plurality of electrodes A and a plurality of electrodes C arranged in series in an alternating manner, as described above, a conductive neutral substrate is disposed between each adjacent electrode A and electrode C, and a non-conductive substrate, e.g. a non-conductive gasket, is disposed between each electrode and adjacent conductive neutral substrate. The one or more electrodes A and the one or more electrodes C may be fully or partially submerged in water. Preferably, the electrodes are partially submerged in water. The electrodes A and C may comprise any suitable conducting material. The electrodes may comprise for example a metal. The metal may be selected from, for example, platinum, copper and stainless steel. The stainless steel may, for example, be a 316 or 304 stainless steel.

The electrolytic cell is operated by attaching the one or more electrodes A and one or more electrodes C to an electrical power source, such that the electrodes A act as anodes and the electrodes C act as cathodes. In operation, in a vehicle comprising an alternator 23, the electrolytic cell is preferably electrically connected to the alternator, such that it can draw power from the alternator (since this does not impinge on the power used to charge the vehicle's battery 22) and carry out the electrolytic generation of hydrogen and oxygen. The water in the cell partially covers the electrodes A and C and the neutral conducting substrates. Each cell is completed by positive and negative terminals. Inlet and outlet tubes from the cell give a feed and return system to a bubbler/reservoir (not shown on diagram) which ensures a constant level of electrolyte within the dry cell and an outlet for the generated gas, i.e. the gas stream containing hydrogen.

The water in the electrolytic cell may comprise an electrolyte to promote the conductance of the water. The electrolyte may be any suitable ionic species that can dissolve in the water, and allow the cell to produce hydrogen. Such electrolytes are known to the skilled person. The electrolyte may, for example, be an alkali metal hydroxide, optionally selected from sodium or potassium hydroxide.

If the hydrocarbon fuel is or comprises a liquid hydrocarbon fuel, and the liquid hydrocarbon fuel is being delivered to an internal combustion engine using a fuel pump operating at a pressure P, with the gas stream containing hydrogen and the liquid hydrocarbon fuel being contacted after the liquid hydrocarbon fuel has left the fuel pump and before it is delivered to the internal combustion engine as an enriched liquid hydrocarbon fuel, the gas stream containing hydrogen is preferably contacted with, e.g. passed through, the liquid hydrocarbon fuel at a pressure of more than P. If the hydrocarbon fuel is or comprises a liquid hydrocarbon fuel, and, following the contacting with the gas stream containing hydrogen gas, the liquid enriched hydrocarbon fuel is passed to an injector pump of an internal combustion engine for injection into a combustion chamber of the engine, the injector pump having a working pressure P', preferably the liquid hydrocarbon fuel is contacted with the gas stream containing hydrogen gas at a pressure less than P' . A system of the invention may be adapted such that the gas stream containing hydrogen is contacted with the hydrocarbon fuel at the pressures mentioned above.

The enriching unit 6A may comprise a device (otherwise termed herein an enrichment device) for diffusing gas into a liquid, comprising: a first gas chamber portion having a gas inlet for introducing gas into the first gas chamber portion; a liquid chamber portion having a liquid inlet for introducing liquid into the liquid chamber portion and a liquid outlet, wherein the first gas chamber portion and the liquid chamber portion are in fluid communication with each other; and means for pressurising the first gas chamber portion, wherein when the first gas chamber portion is pressurised, the gas in the first gas chamber portion is diffused into the liquid in the liquid chamber portion.

The means for pressurising the first gas chamber portion may be any means that can reduce the volume within which the gas in the first gas chamber portion is contained or increase the amount of gas within the first gas chamber or a combination thereof. The means for pressurising the first gas chamber portion may comprise a piston slidably displaceable within the first gas chamber portion.

Preferably, the piston is arranged to be driven by any suitable means, including, but not limited to, an electrical means for example a solenoid, pneumatic means for example compressed gas, or a screw pump. The piston can be driven a desired number of cycles per minute, typically about 10 to about 30, and preferably about 15 to about 25, most preferably at about 20 cycles per minute.

Preferably, the gas inlet in the first gas chamber portion is provided with a gas inlet valve which is arranged to control the supply of gas to the first gas chamber portion. Preferably, the gas inlet valve is a solenoid valve.

Optionally, the first gas chamber portion is provided with a pressure relief valve.

The enrichment device may further comprise a non-return valve disposed between the first gas chamber portion and the liquid chamber portion that allows fluid flow from the first gas chamber portion to the liquid chamber portion.

The enrichment device may further comprise a diffuser screen disposed within the liquid chamber portion, wherein, in use, the gas passes through the diffuser screen so as to promote uniform diffusion of the gas into the liquid. Optionally, the liquid chamber portion and the first gas chamber portion are separated from each other by a partition provided with a fluid passageway, wherein the diffuser screen is resiliently biased towards the partition such that when the gas in the first gas chamber portion is pressurised the diffuser screen moves away from the partition allowing the pressurised gas to flow to a region of the liquid chamber portion between the partition and the diffuser screen and through the diffuser screen into the liquid in the liquid chamber portion.

Optionally, the liquid inlet is provided with a non-return valve that allows fluid flow into the liquid chamber.

The enrichment device may further comprise a second gas chamber portion that is in fluid communication with the liquid chamber portion through a semi-permeable membrane, the second gas chamber portion having a gas outlet, wherein in use gas can flow from the liquid chamber portion through the semi-permeable membrane into the second gas chamber portion and exit the device through the gas outlet. The semi-perm ea ble m em bra n e , m ay be sel ective for eith er hyd rogen (ove r hydrocarbons) or hydrocarbons (over hydrogen), to produce, in use, a permeate enriched , respectively, in hydrogen or hydrocarbons, with the retentate being enriched , respectively, in hyd rocarbons or hydrogen . Such semi-permeable membranes are described below.

Optionally, the gas outlet is provided with a gas outlet valve, which is optionally a solenoid valve. The enrichment device may further comprise an intermediate chamber portion situated between the liquid chamber portion and the second gas chamber portion, the intermediate chamber portion being separated from the liquid chamber portion by a baffle plate and from the second gas chamber portion by the semi-permeable membrane.

The liquid inlet in the first gas chamber portion may be in fluid connection with a source of hydrocarbon fuel, optionally a source of liquid hydrocarbon fuel. The gas inlet of the first gas chamber portion may be in fluid connection with a hydrogen source and/or an oxygen source. The gas inlet of the first gas chamber portion may be in fluid connection with a hydrogen production unit and/or an oxygen production un it. Optionally, in a vehicle com prising the en richment device, an internal combustion engine having one or more fuel injector pumps, a fuel tank, the liquid inlet of the enrichment device is in fluid communication with the vehicle fuel tank, the gas inlet is in fluid communication with a hydrogen source or a hydrogen production unit, which may be as described herein, and the liquid outlet is in fluid communication with the one or more fuel injector pumps of the internal combustion engine.

Optionally, in using the enriching unit, the liquid is a liquid hydrocarbon fuel and the gas diffused into the liquid in the liquid chamber portion is a gas stream containing hydrogen and optionally oxygen, and the pressure in the liquid chamber portion is a pressure for contacting the hydrocarbon fuel with the gas stream containing hydrogen, as described herein.

Optionally, the enriched hydrocarbon fuel is heated to a temperature of about 50 °C or more in the pre-heat unit 7, and then passed to an internal combustion engine.

Optionally, the enriched hydrocarbon fuel is placed in a magnetic field, and then delivered to an internal combustion engine. Optionally, the enriched hydrocarbon fuel is heated to a temperature of about 50 °C or more and placed in a magnetic field, and then delivered to an internal combustion engine. The magnetic field may be generated by any suitable magnet or magnets. The magnet or magnets may be permanent or electromagnets. Preferably, the magnetic field produced by the magnet or magnets is an oscillating magnetic field. The maximum strength of the oscillating magnetic field may be at least 0.5 T, optionally, at least 1 T, optionally at least 2 T. The field may oscillate with a frequency of at least 1 Hz, optionally at least 10 Hz, optionally at least 100 Hz, optionally at least 1000 Hz, optionally at least 10 MHz, optionally at least 100 MHz, optionally at least 300 MHz, optionally at least 500 M Hz. Optionally, the magnetic field may be a produced by superheterodyne magnets. Such magnets are known to the skilled person.

Optionally, the contacting of the gas stream containing hydrogen gas and oxygen gas with the hydrocarbon fuel produces the enriched hydrocarbon fuel and a gaseous mixture, the process further comprising separating the enriched hydrocarbon fuel and the gaseous mixture. The enriched hydrocarbon fuel may be returned to the fuel tank, or delivered the to the internal combustion engine, optionally at a fuel inlet, and the gaseous mixture may be delivered to the internal combustion engine, optionally at an air inlet. The separating of the enriched hydrocarbon fuel and the gaseous mixture may be effected by any suitable means. Preferably, the enriched hyd rocarbon fuel and gaseous mixture are contacted with a semi-permeable membrane, which is selective for either hyd rogen (over hyd rocarbons) or hydrocarbons (over hydrogen), to produce a permeate enriched, respectively, in hydrogen or hydrocarbons, with the retentate being enriched , respectively, in hydrocarbons or hydrogen. Such semi-permeable membranes are known to the skilled person. The present inventors have found that it is preferable for the enriched hydrocarbon fuel and gaseous mixtu re are contacted with a sem i-permeable membrane, wh ich is selective for either hyd rogen (over hydrocarbons). The membrane may, for example, comprise a glassy membrane, such as polyetherimide, wh ich is gen eral ly selective for smal l molecu les , such as hyd rogen , over hydrocarbons. Such semi-permeable membranes are preferably selected from materials including polyimides, polysulfones, and polyethylene or polypropylene. The membrane may be a membrane as described in WO 2004/039874. The membrane may be a mixed matrix membrane. The membrane is preferably a porous membrane having pores with a size of at least 10 microns, optionally at least 100 microns. The membrane is preferably a porous sintered polyethylene or polypropylene membrane having pores having a pore size of 10 to 100 microns, optionally having a thickness of from 0.75 to 10 mm. Such membranes are available under the tradename i-Vyon and are produced by Porvair Filtration Group.

Optionally, in the process, the enriched hydrocarbon fuel is passed to an internal combustion engine, the internal combustion engine is running and unused hydrocarbon fuel from the internal combustion engine is circulated such that, after it has left the internal combustion engine, it is contacted with the gas stream containing hydrogen such that at least some of the hydrogen gas and oxygen gas is introduced into the hydrocarbon fuel to produce an enriched hydrocarbon fuel, and then passed back to the internal combustion engine.

Optionally, the process is controlled by an electronic fuel injection enhancement device (an EFI E device 20). Such devices are known to those skilled in the art. Such devices are typically adapted such that, when attached to the wiring connecting an oxygen sensor of a vehicle to the vehicle's computer, an offset to the voltage coming from the oxygen sensor is applied. This effectively informs the vehicle's computer that the oxygen content within the engine is at a normal level, and avoids the vehicle, for example, pumping more fuel into the engine when this would not be desirable. The EFIE devices can optionally control one or more other processes in or related to an internal combustion engine, including, but not limited to, launch control , boost, water injection , nitrous injection , fuel injection devices, drive manifold components such as manifold flaps, solenoids within the engine and associated devices e.g. cam solenoids.

Optionally, the process is controlled by a two-dimensional (sometimes termed a two- map) electronic fuel injection enhancement device, optionally a three-dimensional electronic (or three-map) fuel injection enhancement device, optionally a four- dimensional (or four-map) electronic fuel injection enhancement device, preferably a five dimensional (or five-map) electronic fuel injection enhancement device.

As can therefore be seen, the present invention may provide, a system for enriching hydrocarbon fuel, the device comprising: a hydrogen production unit for producing a gas stream containing hydrogen, an enriching unit for contacting a hydrocarbon fuel and a gas stream containing hydrogen such that at least some of the hydrogen gas is introduced into the hydrocarbon fuel to produce an enriched hydrocarbon fuel, the hydrogen production unit being in fluid connection with the enriching unit such that the gas stream containing hydrogen is passed to the enriching unit, the enriching unit having an inlet for the hydrocarbon fuel, and an outlet for the enriched hydrocarbon fuel. The system may be used for carrying out a process of the invention, the process further comprising producing hydrogen in the hydrogen production unit, and then, in step (i) contacting the hydrogen gas with the hydrocarbon fuel in the enriching unit.

The device may be used for carrying out the process of the first aspect, the process further comprising producing hydrogen in the hydrogen production unit and oxygen in the oxygen production unit, and then, in step (i) contacting the hydrogen gas and oxygen gas with the hydrocarbon fuel in the enriching unit.

In the embodiment of figure 1 the first electrolytic cell 1 acts as a source of hydrogen gas and a source of oxygen gas. The invention is not however limited to this and in general requires only the provision of a suitable source of hydrogen gas and a suitable source of oxygen gas; the source of hydrogen gas may or may not be separate from the sou rce of oxygen gas. The hydrogen source or hydrogen production unit may be any suitable unit for supplying hydrogen gas to the enriching unit. The hydrogen source or hydrogen production unit may be a unit that can store hydrogen and supply hydrogen gas as required to the enriching unit. A unit that can store hydrogen may store the hydrogen in gaseous, liquid or chemically bound form, and release it as required.

Units for storing hydrogen in its gaseous form are known to the skilled person and may comprise a chamber, typically a cylinder, containing hydrogen under pressure that can be released upon opening a valve. The unit for storing hydrogen may be a unit typically termed a hydrogen tank (otherwise known as a hydrogen cartridge or canister), which can store hydrogen under pressure, such as pressures from about 150 bar or more, optionally from about 300 bar or more, optionally from about 500 bar or more.

Units for storing hydrogen in its liquid state are known to the skilled person. Such units typically store the hydrogen under pressure and at very low temperatures, e.g. a temperature of about 20.28 K.

The unit for storing hydrogen may be a unit that stores hydrogen in a chemically bound form. Such units can include materials that bind to hydrogen, and release it when desired, typically by heating the materials. Such materials are known to the skilled person. The unit may include a material such as a metal hydride, where the metal may be selected from an alkali metal, alkali earth metal and a transition metal; a metal organic framework; carbon nanotubes; and imidazolium ionic liquids. Other materials known to the skilled person may be used. Such materials for hydrogen storage are described in the art.

The oxygen source or oxygen production unit may be any suitable unit for supplying oxygen gas to the enriching unit. The oxygen source or oxygen production unit may be a unit that can store oxygen and supply oxygen gas as required to the enriching unit. A unit that can store oxygen may store the oxygen in gaseous, liquid or chemically bound form, and release it as required.

Units for storing oxygen in its gaseous form are known to the skilled person and may comprise a chamber, typically a cylinder, containing oxygen under pressure that can be released upon opening a valve. The unit for storing oxygen may be a unit typically termed a oxygen tank (otherwise known as a oxygen cartridge or canister), which can store oxygen under pressure, such as pressures from about 150 bar or more, optionally from about 300 bar or more, optionally from about 500 bar or more. Typically, oxygen is stored at a pressure of 200 bar or less.

Units for storing oxygen in its liquid state are known to the skilled person. Such units typically store the oxygen under pressure, typically up to pressures of 200 bar, and at very low temperatures, e.g. a temperature of about 90.19 K or less.

Preferably the hydrogen source or production unit is a unit that can produce hydrogen from one or more chemical substances. The hydrogen may be produced, in a method selected from a steam reforming process from hydrocarbon fuels, for example methane, reforming of an alkanol, such as methanol, and an electrolysis from a suitable medium, for example water. The hydrogen source or hydrogen production unit is preferably one that can produce hydrogen from one or more chemical substances, since the hydrogen gas can be produced when required, which avoids the need to have to store large volumes of hydrogen gas or having to store it in its liquid form, which requires high pressure and low temperatures.

Preferably the oxygen source or production unit is a unit that can produce oxygen from one or more chemical substances. The oxygen may be produced, for example, in an electrolytic process from a suitable medium, such as water. In an embodiment, the oxygen may be produced in a chemical oxygen generator. A chemical oxygen generator is a generator of oxygen from a chemical reaction, typically without any requirement for electrolysis. For example, a chemical oxygen generator may produce oxygen by reaction of an oxygen-containing species with another species. The oxygen-containing species may, for example, be selected from a superoxide, a chlorate, a perchlorate and an ozonide. An example commercially available oxygen generator produces oxygen from the reaction of sodium chlorate (NaCI0 ₃ ), barium peroxide (Ba0 ₂ ) and potassium perchlorate (KCI0 ₄ ) with a lead styphnate and tetrazene mixture. A further example of a unit for producing oxygen is a chlorate candle, sometimes termed an oxygen candle, which generates oxygen from a mix of sodium chlorate and iron powder. Most preferably, the oxygen source or oxygen production u nit is a unit that comprises one or more cells for the electrolytic production of oxygen.

The hydrogen source and oxygen source may be the same or different sources. The hydrogen production unit and oxygen production unit may be the same or different units.

Most preferably, the hydrogen source or the hydrogen production unit is a unit that comprises one or more cells for the electrolytic production of hydrogen, preferably the electrolytic production of hydrogen and oxygen from a suitable liquid medium. Most preferably, the oxygen source or the oxygen production unit is a unit that comprises one or more cells for the electrolytic production of oxygen, preferably the electrolytic production of hydrogen and oxygen from a suitable liquid medium. The liquid medium may comprise water and optionally one or more electrolytes. The electrolytes may be selected from an organic acid, such as acetic acid; a metal carbonate, where the metal may, for example, be an alkali metal, e.g. potassium or sodium, e.g. in K ₂ C0 ₃ ; and a metal hydroxide, where the metal may, metal may, for example, be an alkali metal, e.g. potassium or sodium. The one or more cells for the electrolytic production of hydrogen and oxygen may comprise a means for refilling the cells with water as required.

As noted the process of the invention may further comprise passing the gas stream containing hydrogen and oxygen through a purification unit to remove one or more species other than hydrogen gas to produce a purified gas stream containing hydrogen gas and oxygen gas. The purified gas stream may then be contacted with the hydrocarbon fuel such that at least some of the hydrogen gas and at least some of the oxygen gas is introduced into the hydrocarbon fuel to produce the enriched hydrocarbon fuel. The contacting may be carried out in the enriching unit, as descri bed herei n . " Removi ng one or more species" i ncl udes red ucing the concentration (e.g. in mass of the one or more species per volume of the gas stream or volume of the one or more species per volume of the gas stream) in the gas stream containing hydrogen. It may reduce the concentration of the one or more species by 50 %, optionally by 80 %, optionally by 90 %, optionally by 95%, where the concentration of the species is mass of the one or more species per volume of the gas stream or volume of the one or more species per volume of the gas stream. Optionally, the one or more species may be removed completely from the gas stream.

The purification unit preferably removes one or more species other than hydrogen. The one or more species other than hydrogen may be removed entirely or in part from the gas stream. Preferably, oxygen is not removed from the gas stream, since this has been found to enhance the combustion process of the enriched hydrocarbon fuel within an internal combustion engine.

The purification unit preferably removes a species from the gas stream that is soluble in water. If the gas stream being purified has been produced in an electrolytic process that uses water containing an electrolyte, the purification unit is preferably adapted to remove the electrolyte species that may be present in the gas stream. The one or more species may be acid or alkaline when dissolved in water.

The purification unit preferably comprises one or more chambers containing a polar liquid medium, the one or more chambers being adapted for passing the gas stream containing hydrogen through the polar liquid medium in the one or more chambers. The polar liquid medium may comprise a polar protic solvent. The polar liquid medium preferably comprises water, most preferably deionised water.

The purification unit preferably comprises one or more desiccation units for removal of water from the gas stream. The desiccation unit may be any known means for the removal of water. The desiccation means may comprise any suitable material that is suitable for the removal of water from a gas. The desiccation unit may comprise a hygroscopic material. The hygroscopic material may include a hygroscopic inorganic salt, including, but not limited to, metal halides and metal hydroxides. The metal may be selected from alkali metals, alkali earth metals and transition metals. The hygroscopic material may be selected from zinc chloride, calcium chloride, potassium hydroxide and sodium hydroxide.

In a preferable embodiment, the one or more desiccation units comprise one or more molecular sieves for the removal of water. The one or more molecular sieves may comprise a zeolite. The zeolite is preferably capable of allowing hydrogen gas to pass through, but remove water from the gas stream passing through the zeolite. The zeolite is preferably selected from zeolite 3A, 4A, 5A and 13X. Most preferably, the zeolite is selected from zeolite 4A and 5A. The one or more molecular sieves may be in particulate form, for example as a powder or pellets. In an embodiment, the one or more desiccation units may comprise a chamber through which the gas stream containing hydrogen gas is passed, the chamber comprising one or more molecular sieves. The one or more molecular sieves may be in particulate form fill ing, completely or at least partial ly, the chamber in the desiccation u n it. Alternatively, the one or more molecular sieves may be in the form of continuous mass that fills, completely or at least partially, the chamber in the desiccation unit.

In an embodiment, the desiccation unit comprises a first chamber having a first wall, a second wall and one or more third walls, wherein the first and second walls are permeable to hydrogen and water, and the one or more third walls is impermeable to hydrogen and water, and one or more materials for the removal of water from a gas are disposed in the chamber. In use, the gas stream is passed through the first wall, contacts the one or more materials for the removal of water from a gas, and purified gas stream exits the chamber through the second wall. The first and second walls are preferably porous. The first and second walls may comprise a metal. The one or more materials for the removal of water from a gas may be selected from the hygroscopic materials and molecular sieves mentioned above. Preferably, the one or more materials for the removal of water from a gas comprise molecular sieves. The one or more materials for the removal of water from a gas may be in particulate form, and first and second walls may be porous and have pores that are smaller in diameter than the smallest diameter of most of the particles of the one or more materials for the removal of water from a gas. "Most of" includes, but is not limited to, at least 90 % by weight, optionally at least 95 % by weight, most preferably at least 99 % by weight of the particles. At least some of the particles, optionally at least 50 % by weight, optionally at least 75 % by weight, optionally at least 90 % by weight, of the one or more materials for the removal of water may have a minimum diameter of at least 200 μηη, optionally at least 500 μηη, optionally at least 0.1 mm, optionally at least 1 mm . I n an embodiment, one or both of the first and second walls may comprise a sintered metal. The sintered metal may comprise a metal selected from bronze, brass and stainless steel. The sintered metal may comprise pores having maximum diameters of 200 μηη or less, optionally, 150 μηη or less, optionally, 100 μηη or less, optionally 50 μηη or less.

The chamber may be of any suitable three dimensional shape, including, but not limited, to cylindrical, cubic and rectangular prism, with the first and second walls preferably being opposed to one another, and the remaining walls constituting the one or more third walls. Preferably, the chamber is the form of a cylinder, with the first and second walls forming the circular end walls and the third wall forming the cylindrical wall joining first and second walls.

The one or more third walls may be made of any suitable material impermeable to hydrogen and water. Such materials are known to the skilled person, and include, but are not limited to, metals such as steel. The one or more third walls are preferably non-porous.

In an embodiment, the desiccation unit comprises a first chamber as described above, and optionally

(i) a second chamber disposed on the opposite side of the first wall, the second chamber being substantially free of the one or more materials for the removal of water from a gas; and/or

(ii) a third chamber disposed on the opposite side of the second wall, the third chamber being substantially free of the one or more materials for the removal of water from a gas. The second chamber may comprise one or more inlets for allowing the gas stream containing hydrogen to enter the second chamber. The third chamber may comprise one or more outlets for allowing the gas stream containing hydrogen to exit the third chamber. The second chamber preferably defines a void that can be filled with the gas stream containing hydrogen, such that the gas stream contacts substantially all of the surface of the first wall, to allow its passage through to the first chamber. "Substantially all of the surface of the first wall" includes, but is not limited, at least 80 % of the area of the first wall, optionally at least 90 % of the area of the first wall, optionally at least 90% of the area of the first wall.

The present invention further provides an internal combustion engine having a system of the invention attached thereto, the system having a conduit for delivery of the enriched hydrocarbon fuel to a fuel air intake of the internal combustion engine.

The present invention further provides a vehicle comprising an internal combustion engine having a system of the invention attached thereto, as described herein.

The hydrocarbon fuel may comprise a fuel for use in an internal combustion engine. The hydrocarbon fuel may comprise petroleum , for example petroleum spirit, sometimes termed gasoline (in the US) or petrol (in the UK), diesel, liquefied petroleum gas, compressed natural gas , jet fuel, biodiesel and alcohols, such as ethanol.

Gasoline, or petroleum, typically comprises hydrocarbons containing between 4 and 12 carbon atoms per molecu le. Gasoline, or petroleum , typically comprises hydrocarbons that are produced in the distillation of crude oil, such hydrocarbons being distilled from the crude oil at a temperature of from about 30 °C to about 200 ° C at atmospheric pressure. The gasoline or petroleum used in the process or device of the present invention may have an octane rating, prior to contact with the gas stream containing hydrogen, of at least 50, optionally at least 60, optionally at least 70, optionally at least 80, optionally at least 90. The gasoline or petroleum used in the process or device of the present invention may have an octane rating, prior to contact with the gas stream containing hydrogen, of from 85 to 93.

Diesel typically comprises hydrocarbons containing between 8 and 21 carbon atoms per molecule. Gasoline typically comprises hydrocarbons that are produced in the distillation of crude oil, such hydrocarbons being distilled from the crude oil at a temperature of from about 200 °C and 350 °C at atmospheric pressure.

An internal combustion engine is a term known to the skilled person. It is typically a mechanical device in which a fuel can be combusted in a combustion chamber, such that the expansion of gases in the combustion chamber applies a force to a movable component of an engine, such as a piston.

The internal combustion engine may be selected from a two-stroke engine, a four- stroke engine, a six stroke engine and a Wankel rotary engine. A four stroke engine is an engine in which the movable component of the engine, such as a piston, goes through a cycle having four steps. Such steps are typically (i) the intake of fuel and an oxidising gas into the combustion chamber, (ii) compression of the fuel and oxidising gas, (iii) combustion of the fuel and oxidising gas such that the movable parts within the chamber are moved by the expansion of the gases, and (iv) exhaustion, in which the combustion products are exhausted to the atmosphere.

The internal combustion engine may be a petroleum engine or a diesel engine. A petroleum engine is an engine in which the fuel is ignited in a combustion chamber with an electrical spark. A diesel engine is an engine that is adapted such that the fuel is ignited by the compression of the fuel and heat of the engine, rather than an ignition with an electrical spark.

The internal combustion engine may comprise one or more air inlets (sometimes termed air inlet manifolds), one or more combustion chambers in fluid connection with the air inlets, one or more fuel inlets for introduction of hydrocarbon fuel into the engine. The one or more fuel inlets may comprise one or more fuel injection devices for injecting fuel into the engine. The one or more fuel inlets may introduce the fuel into the one or more combustion chambers or into the one or more air inlets.

In an embodiment, the enriched hydrocarbon fuel may be delivered into the engine through the fuel inlets. In a preferred embodiment, the enriched hydrocarbon fuel is delivered into the engine through one or more fuel injection devices, the fuel injection device optionally delivering the enriched hydrocarbon fuel to the air intake and/or the one or more combustion chambers.

In an embodiment, the enriched hydrocarbon fuel is delivered into the engine through a fuel inlet, optionally as described above, and a gas stream containing hydrogen and oxygen produced in an electrolytic process from water is delivered to the engine through the air inlet. As described above, optionally, the water may contain an electrolyte, which may be as described herein. Figure 2 shows one embodiment of the fuel enrichment device 6A. The fuel enrichment device 100 comprises a substantially cylindrical vessel 102 that is divided into a number of chamber portions by dividers or partitions. The vessel 1 02 is separated into a first gas chamber portion 104, a liquid chamber portion 106, an intermediate chamber portion 108 and a second gas chamber portion 1 10. Although in this embodiment the chamber portions are sub-divisions of a single vessel, in other embodiments, each chamber portion may be formed from a single vessel with the vessels fluidly interconnected.

The fuel enrichment device 100 can be connected to a vehicle having an internal combustion engine and used to enhance a liquid hydrocarbon fuel, such as petrol or diesel, with hydrogen. In the present embodiment, the device 100 comprises a gas inlet 122 which is connected to the pressure control valve (5, 138), a liquid inlet 136 which is connected to the fuel tank of the vehicle, which may contain petrol or diesel for example, a liquid outlet 140 which is connected to the fuel injector pumps of the engine, and a gas outlet 150 which is connected to the air intake manifold of the engine. The fuel enrichment device 100 is used to dissolve hydrogen gas into the liquid hydrocarbon fuel, thereby enhancing its properties.

The first gas chamber portion 104 is at the bottom of the vessel 102 and is delimited by the base 1 12 of the vessel, the side walls 1 14 of the vessel and a partition 1 16. The partition 1 16 is substantially parallel to the base 1 12 and extends across the whole of the cross-section of the vessel 102. The partition 1 16 is provided with a fluid passageway 1 18 that is located in the centre of the partition and a non-return valve 120 is disposed in the fluid passageway 1 18. The non-return valve 120 is set at approximately 1 -2 psi (6.89-13.79 kPa). The fluid passageway 1 18 allows fluid communication between the first gas chamber portion 104 and the liquid chamber portion 106 which is positioned above the partition. The non-return valve 120 allows fluid flow from the first gas chamber portion 104 to the liquid chamber portion 106 when the pressure in the first gas chamber portion 1 04 exceeds the threshold pressure of the non-return valve 120, but prevents fluid flow in the opposite direction. The first gas chamber portion 104 is also provided with the gas inlet 122 that allows gas from a gas source (e.g. the gas stream containing hydrogen deriving from the first cell) to be introduced into the first gas chamber portion 104. The gas inlet 122 is provided with a solenoid-driven gas inlet valve 124 that controls the supply of gas to the first gas chamber portion 104. The first gas chamber portion 104 also has a pressure relief valve 126 that is set at an appropriate preset value. When the pressure in the first gas chamber portion 104 exceeds the preset value, the pressure relief valve 126 opens and gas is discharged from the first gas chamber portion 104 causing the pressure in the first gas chamber portion 104 to be reduced . This prevents the pressu re in the first gas cham ber portion 1 04 from becomi ng excessively high.

The fuel enrichment device 100 comprises a means for pressurising the gas in the first gas chamber portion 1 04. I n th is particular embodiment the means for pressurising the gas in the first gas chamber portion 104 is a piston 128 that is slidably disposed in the first gas chamber portion 104. The piston 128 extends across substantially the whole of the cross section of the first gas chamber portion 104 and can slide in the general axial direction of the vessel 102. The piston 128 is sealed against the inner surface of the side walls 1 14 of the first gas chamber portion 104 using two O-rings 130 that circumferentially extend around the piston 128. The piston 128 is driven by a solenoid actuator 132 which can move the piston 128 up and down within the first gas chamber portion 104. In Figure 1 , the piston 128 and the solenoid actuator 132 form the solenoid valve 6C, which is driven from a signal in the pressure switch, 6B. The piston 128 can be driven a desired number of cycles per minute by the actuator 132, typically 10 to 30, and preferably about 20 cycles per minute.

When the piston begins its compression stroke the pressure control valve (5) shown in Figure 1 closes to prevent gas being back pressurised into the gas feed from the molecular sieve trap (4). The non-return valve opens and allows the compressed gas to enter the upper chamber. The sprung gauze is lifted slightly to allow the gas to spread beneath it and allow uniform diffusion through the fuel. The saturation level of the gases in the fuel will be determined by the ratio of volume A to volume B as detailed above.

The liquid chamber portion 106 is positioned above the first gas chamber portion 104 and is delimited by the partition 1 16, the side walls 1 14 of the vessel 102 and a baffle plate 134. The baffle plate 134 is substantially parallel to the partition 1 16 and extends across the entire cross-section of the vessel 102. The baffle plate 134 is provided with a plurality of apertures that provide fluid communication between the liquid chamber portion 106 and the intermediate chamber portion 108. The liquid chamber portion 106 is provided with the liquid inlet 136 that allows liquid fuel to be introduced into the liquid chamber portion 106. A non-return valve 138 is disposed in the liquid inlet 136 and allows flow into the liquid chamber portion 106 but prevents flow out of the liquid chamber portion 106 through the liquid inlet 136. The non-return valve 138 is set at approximately 1 -2 psi (6.89-13.79 kPa) below the fuel pump operating pressure of the fuel delivery system of the vehicle. The liquid chamber portion 104 is also provided with the liquid outlet 140. A diffuser screen 142, in the form of a bronze gauze, is disposed towards the bottom of the liquid chamber portion 106. The diffuser screen 142 is substantially parallel to the partition and extends across substantially the entire cross-section of the liquid chamber 106. The diffuser screen 142 is resiliency biased towards to the partition 1 16 by a plurality of springs 144 connected between the underside of the screen 142 and the upper surface of the partition 1 16. In a resting state the diffuser screen 142 rests against the upper surface of the partition 1 16. When the pressure in the first gas chamber portion 104 increases and exceeds the preset value of the non-return valve 120, the valve opens and gas enters the liquid chamber portion 106 through the fluid passageway 1 18 and this causes the diffuser screen 142 to axially move away (or lift) from the partition 1 16. This allows the pressurised gas to flow to a region of the liquid chamber portion 106 between the partition 1 16 and the diffuser screen 142 and through the diffuser screen 142 into the liquid chamber portion 106.

The relative volumes of the first gas chamber portion 104 and the liquid chamber portion 106 can be adjusted depending on the engine type and the level of saturation of the hydrogen into the fuel required. The volumetric ratio of the first gas chamber portion 104 to the liquid chamber portion 106 preferably fulfils the ratio X+0.5:1 where X is the operating pressure of the fuel pump of the vehicle's fuel delivery system in bars.

A semi-permeable membrane 146 is disposed above the baffle plate 1 34 and extends across the entire cross-section of the vessel 1 02. The semi-permeable membrane 146 defines a second gas chamber portion 1 10 between the top 148 of the vessel and the side walls 1 14 and defines an intermediate chamber portion 108 between the baffle plate 1 34 and the side walls 1 14. The second gas chamber portion 1 1 0 is provided with a gas outlet 1 50 that is provided with a solenoid- controlled valve 152. The valve 152 controls the flow of gas out of the second gas chamber portion 1 10 through the gas outlet 150.

In use, with the piston 128 positioned at the bottom of the first gas chamber portion 104, the first gas chamber portion 104 is filled with a hydrogen/oxygen gas mixture through the gas inlet 122. The flow of gas into the chamber 104 is controlled by the valve 124. Liquid hydrocarbon fuel, such as petrol, from the vehicle's fuel tank fills the liquid chamber potion 1 06. This is controlled by the vehicle's fuel delivery system. The piston 128 then moves upwards within the first gas chamber portion 104 to compress the hydrogen/oxygen gas. This increases the pressure of the gas which causes it to flow into the liquid chamber portion 106 through the non-return valve 120 in the fluid passageway 1 1 8. The pressurised hydrogen/oxygen gas causes the diffuser screen 142 to move away from the partition 1 16 which allows the pressurised gas to flow to a region between the screen 142 and the partition 1 16. The pressurised hydrogen/oxygen gas then flows through the diffuser screen 142 and into the liquid hydrocarbon fuel within the liquid chamber portion 106. The diffuser screen 142 helps to promote the uniform diffusion of the hydrogen/oxygen gas into the liquid fuel. The pressure of the hydrogen/oxygen gas causes the hydrogen to diffuse through the fuel and dissolve into it. The hydrogen displaces the nitrogen from the fuel and any excess gas and fuel vapour is forced through the baffle plate 134 into the intermediate chamber portion. The fuel in the liquid chamber 106 is enriched, or enhanced, with hydrogen and is delivered through the liquid outlet to the fuel injector pumps of the vehicle's engine. At least some of the fuel vapour is retained in the intermediate chamber portion by the semi-permeable membrane 146 and any excess gas, such as hydrogen/oxygen/nitrogen, passes through the semipermeable membrane 146 into the second gas chamber portion 1 10. This excess gas can then be fed to the air intake manifold of the vehicle's engine through the gas outlet 150. The excess gas may contain fuel vapour which can be fed to the air intake manifold of the engine.

Compressing hydrogen and oxygen into the liquid hydrocarbon fuel provides a number of benefits. Some hydrogen and oxygen is dissolved into the fuel which causes partial saturation of the fuel. This increases the octane rating, or RON, of the fuel. Dissolved impurities within the fuel, such as nitrogen, are forced out of solution by the hydrogen/oxygen and this prevents or reduces the formation of NOx during the combustion process. The partially saturated fuel fed to the fuel injector pumps from the liquid outlet 140 has a reduced viscosity which leads to a much finer misting on passing though the fuel injector system. This gives much better mixing with the enriched air from the air intake manifold and thus results in improved burning characteristics (combustion efficiency).

As the piston 128 moves back down to the bottom of the first gas chamber portion 104 the pressure within the vessel 102 reduces and the diffuser plate 106 returns to a resting position in which it sits on top of, or close to, the partition 1 16. The cycle then starts aga i n with the fi rst gas chamber portion 104 being filled with hydrogen/oxygen gas and the liquid chamber portion 106 filling with liquid fuel. The diffuser plate may comprise any suitable material, for example a metal or alloy. In a preferred embodiment, the diffuser plate comprises bronze.

Displaced and excess gases from the fuel are passed through the semi-permeable membrane as described above, which may be constructed of Vyon®R (commercially available from Porvair Filtration Group) which retains the majority of any fuel in the excess gas in the upper chamber whilst allowing the hydrogen and oxygen to pass through. This gas exits via a solenoid valve and is introduced into the engine air intake (9) to be burned as part of the combustion process.

The enhanced fuel, containing dissolved hydrogen and oxygen, is fed, via a further non return valve set at Y+2 psi (where Y is the desired operating pressure of the upper chamber in psi) into the magnetic pre-heat chamber 7 (if provided).

The partially saturated fuel then undergoes a two stage process in the magnetic preheat chamber 7 which warms the fuel (thus ensuring at least some of the hydrogen and oxygen gas remain in solution and do not "froth") and magnetic realignment of the fuel molecules using one or more magnets, e.g. as described herein, for example su perheterodyne magnets, again known to en hance combustion efficiency. Superheterodyne magnets are known to those skilled in the art and include magnets that produce an oscillating magnetic field. Such magnets have been found to improve the combustion of the hydrocarbon fuel. While not being limited by theory, the present inventors consider that this is due to the interaction of the hydrogen, oxygen and fuel molecules within the oscillating magnetic field, which is believed to produce a closer association of the hydrogen and oxygen with the fuel molecules. The magnetic pre-heat chamber consists of a chamber lined with superheterodyne magnets (to provide the magnetic alignment) and jacketed with warm water from the radiator system, taken off upstream of the radiator thermostat.

This enhanced fuel is fed, via the injector pump 8, into the engine 9 where it is mixed with the air/hydrogen/oxygen mixture from the second dry cell 2 (if provided) and the excess gas/fuel from the fuel enhancement chamber (6a). This mixture is considered to be optimised for combustion.

In the air intake of the engine 9, purified oxygen and hydrogen that originated from the second dry cell 2 replaces a portion of the air to give an enriched air mixture that enhances the combustion process by displacing nitrogen (for every litre of purified gas introduced into the air intake, 0.79 litres of nitrogen (approx) is displaced) and thus reducing the NOx output, and by increasing the overall energy potential of the fuel mixture. The speed of combustion is also dramatically increased and is proportional to the hydrogen: ratio. Hydrogen on its own burns at between 3- 6cm/min as compared with petrol which burns at a speed of 0.2 - 0.9 cm/min. The more hydrogen that is present in the combustion mixture, the quicker the mixture will burn to completion.

Any enhanced fuel that is unused in the process is reintroduced into the vehicle fuel tank 13 via the common fuel return 12. This returned fuel is effectively clean of unwanted dissolved gases and has a higher octane rating due to the presence of dissolved hydrogen. Since the fuel has been partially saturated it is expected that some gas will be released into the bulk fuel supply where it will be absorbed. Thus, the longer the vehicle is run (on the same tank of fuel) the more enriched the bulk fuel will become with dissolved hydrogen and oxygen and the better the efficiency will be. To prevent pressurisation of the fuel tank a pressure relief valve 15 is introduced which will allow any build up of gas/fuel pressure to effectively be relieved into the air intake where it can be safely introduced into the engine for combustion.

Figure 5 shows a diagram of a further embodiment of the Fuel Enhancement Chamber, which differs from that of Figure 2 in that the piston is driven by a screw mechanism, rather than a solenoid.

EFIE and ELECTRONICS The system described above and shown in Figure 1 may be controlled by an EFI E (Electronic Fuel Injection Enhancement) device (20). EFI E devices are known to those skilled in the art. An EFIE is sometimes referred to as an ECU (Engine Control Unit). The EFI E ensures that the engine receives the optimum ignition timing and air/fuel ratio at all RPM and load conditions. Optionally, the EFI E controls the amount of hydrogen and optionally oxygen gas contacted with the hydrocarbon fuel depending on the engine speed. For example, the EFIE can control the ratio 'volu metric rate of delivery of the enriched hyd rocarbon fuel to the internal combustion engine (in L/min):volumetric rate of hyd rogen i n the gas strea m containing hydrogen contacted or passed through the hydrocarbon fuel to produce the enriched hydrocarbon fuel (in L/min)', as described above. The engine is also smoother, delivers greater response and maximises fuel efficiency at all RPM and throttle positions. The EFI E can be programmed to recognise driving style and environment. The EFIE can constantly monitor and adjust the engine levels and the system described above to maximise fuel efficiency. A five map EFI E can be programmed to recognise Urban, Motorway, Off road, Load Carrying and Towing conditions, or, in fact, any particular scenario that may be envisaged for the vehicle in question. It can also be programmed to perform in different theatres such as deserts, maritime, high altitude etc. The EFIE may be supplied with a standard set of optimisation parameters but can be simply reprogrammed by down loading updated parameters via the internet and "Flashing" the EFIE memory by USB connection to a laptop.

This EFI E can be reprogrammed easily, which allows the present invention to be employed in a variety of situations, including, if desired, in military applications, as well as allowing the user of the system to remove the system from their vehicle, and attach it to a new vehicle with minimal cost, with the EFI E simply needing to be reprogrammed for the new vehicle. Suitable programmes may be available on-line.

The EFI E also incorporates a timer circuit (19) that allows the engine management system to go through its health check routine prior to switching on the dry cell gas generators; this prevents the vehicle ECU (21 ) from becoming confused at the difference in combustion characteristics that are present due to the hydrogen/oxygen gas enhancement. The circuit is completed by the addition of a relay 18, master switch 17 and circuit breaker 16.

Figure 6 shows a system according to a further embodiment of the invention in combination with an internal combustion unit 600. The system comprises an HHO generator 601 which generates a gas stream that includes both hydrogen and oxygen. In the embodiment shown in figure 6 the HHO generator 601 is an electrolytic cell, optionally a "dry cell" as described above, that generates hydrogen gas and oxygen gas by electrolysis. Electrolyte for the HHO generator is stored in an electrolyte tank 602, and can pass into the H HO generator 601 through a fluid connector 603. The gas stream containing hydrogen and oxygen that is generated in the H HO generator 601 passes into the electrolyte tank 602, and collects in the electrolyte tank, above the electrolyte. I n the embodiment of figure 6 the fluid connector 603 serves both to carry electrolyte from the electrolyte tank 602 to the HHO generator 601 and to carry the gas stream containing hydrogen and oxygen from the H HO generator 601 to the electrolyte tank 602, although in principle two separate fluid connectors could be used.

When the HHO generator 601 is in operation the pressure within the electrolyte tank 602 will increase above atmospheric pressure, as a result of the collection in the electrolyte tank of the gas stream containing hydrogen and oxygen. The electrolyte tank 602 thus also acts as a receiver for the gas generated by the HHO generator 601 . This pressurisation of the electrolyte tank 602 is used to cause a flow of gas containing hydrogen and oxygen from the electrolyte tank 602 into a fuel enrichment chamber 605 via a fluid connector 604 which is preferably fitted with a non-return valve 604a to prevent fuel passing into the electrolyte tank 602. A hydrocarbon fuel, such as diesel or petrol (gasoline) is also provided to the fuel enrichment chamber 605 from a fuel tank (not shown) via a filter 606 and a fuel pump 607.

There will inevitably be a pressure drop between the electrolyte tank 602 and the fuel enrichment chamber 605 (typically of around 1 bar), but the pressure in the fuel enrichment chamber 605 will still be above atmospheric pressure owing, ultimately, to the pressure created generation of the gas stream in the HHO generator 601. As a result, at least some of the hydrogen gas and at least some of the oxygen gas in the gas stream is introduced into the fuel 608 in the fuel enrichment chamber, at a pressure above atmospheric pressure (that is, at a pressure above 1 bar absolute) to generate an enriched hydrocarbon fuel in the manner described above. In principle the pressure within the fuel enrichment chamber 605 may be any pressure above atmospheric pressure (that is, any pressure above 1 bar absolute), and may for example be any of the pressures or pressure ranges listed above. For many applications, however, it is likely that a pressure in the fuel enrichment chamber 605 of 0.5 bar to 1 bar above atmospheric pressure (that is a pressure of 1.5 bar to 2 bar absolute) will be suitable.

The enriched hydrocarbon fuel may be fed to the fuel injection pump 609 of an internal combustion engine 600 (for example the engine of a vehicle), for example via a fuel filter 61 0 and a pressure reduction value 61 1 . If desired , a preheater, optionally a preheater that also applies a magnetic field, may be provided between the fuel filter 610 and the pressure reduction value 61 1 . If a preheater is provided it may be any of the preheaters described above with reference to the preheater 7 of figure 1 .

Any enriched hydrocarbon fuel that is not used by the fuel injection pump 609 is returned to the return fuel line 612, preferably via a non-return valve 612a, and may be returned either to the fuel tank (not shown) or to the fuel enhancement chamber 605 for example via a suitable pump 613. Returning the enriched hydrocarbon fuel to the fuel enhancement chamber 605 has the effect of allowing the fuel to become progressively enriched in hydrogen and oxygen.

The fuel enhancement chamber 605 is provided with a pressure relief valve 605b which opens when the pressure within the fuel enrichment chamber 605 reaches a pre-set threshold to allow a mixture of hydrocarbon fuel and gas containing hydrogen and oxygen to escape from the fuel enrichment chamber 605 to relive the pressure inside the fuel enrichment chamber 605. The hyd rocarbon fuel and the gas containing hydrogen and oxygen are separated from one another by a fuel/gas separator 614, which may be a known fuel/gas separator 614, and the fuel returned to the fuel tank via the return fuel line 612. The gas containing hydrogen and oxygen may be introduced into the air intake (not shown) of the engine (or, if necessary, may be vented to atmosphere). A non-return valve is preferably provided between the separator 614 and the return fuel line 612, to prevent fuel in the return fuel line 612 from passing into the separator 614. It should be understood that a practical implementation of the embodiment of figure 6 will include other components in addition to those described above. For example, various non-return valves 617 and flames arrestors 618 may optionally be provided as shown in figure 6.

As a further example, the electrolyte tank 602 may contain float switches 602b, 602c for maintaining the level of liquid in the electrolyte tank 602 between a desired lower level and a desired upper level. When the level of liquid drops to the level of the lower float switch 602b this causes de-ionised water to be transferred from a tank 616 into the electrolyte tank 602, for example switching on a pump 615. When the level of liquid in the electrolyte tank 602 reaches the upper float switch 602c the transfer of de-ionised water from the tan k 61 6 into the electrolyte tank 602 is stopped, for example by turning off the pump 615.

One or more float switches 605a (only one shown in figure 6) may also be provided in the fuel enrich ment chamber 605, to regulate the level of liqu id in the fuel enrichment chamber 605.

One or more float switches 616a (only one shown in figure 6) may also be provided in the tank 616, to regulate the level of de-ionised water in the tank 616.

The fuel enrichment chamber 605 may be provided with a pressure-operated switch (shown as 703 in figure 7) that shuts down the HHO generator if the pressure in the fuel enrichment chamber 605 reaches a preset level. Additionally or alternatively the electrolyte tank 602 may be provided with a pressure-operated switch (shown as 704 in figure 7) that shuts down the HHO generator if the pressure in the electrolyte tank 602 reaches a preset level (it should be noted that, since the pressure in the electrolyte tank 602 will be greater than the pressure in the fuel enrichment chamber 605, the preset level that the pressure in the fuel enrichment chamber 605 must reach in order for the H HO generator to be shut off may be lower than the preset level that the pressure in the electrolyte tank 602 must reach in order for the HHO generator to be shut off.

Fuel that is returned from the fuel injection pump 609 to the enrichment chamber 605 may have had its temperature increased as a result of passage through the fuel injection pump. To prevent the temperature in the fuel enrichment chamber 605 becoming too high, fuel that is returned to the enrichment chamber 605 by the pump 613 may be cooled either by making the return pipe to the fuel enrichment chamber 605 sufficiently long to allow the fuel to cool or by providing a cooler to cool the fuel before it is returned to the fuel enrichment chamber 605. Alternatively, a cooler may be provided to cool the fuel enrichment chamber 605.

The embodiment of figure 6 has a number of advantages over the embodiment of figure 1 .

One advantage is that the fuel enrichment chamber of figure 6 is much simpler in construction than the fuel enrichment chamber of figures 2 or 5, and in essence is a simple pressure vessel - the internal pressure generated in the HHO generator 601 is used to pressurise the interior of the fuel enrichment chamber 601 above atmospheric pressure. (It should be noted that the maximum pressure that can be easily obtained in the fuel enrichment chamber 605 of figure 6 may be less than can be obtained in the fuel enrichment chamber of figure 2 or 5, so that a fuel enrichment chamber as shown in figure 2 or 5 may be preferred in an application where a high pressure is desired in the fuel enrichment chamber.)

In the embodiment of figure 6 the gas stream generated by the HHO generator 601 passes through the liquid 602a in the electrolyte tank, and this has been found to clean the gas stream such that the scrubbing unit 3 and drying unit 4 of figure 1 are not required. The filter 610 provided in the delivery line that delivers the enriched fuel to the fuel injection pump 609 may be a conventional fuel filter.

The separator 614 may be a conventional fuel/gas separator, and the use of, for example, a semi-permeable membrane to separate gas and fuel is not required.

The embodiment of figure 1 uses a second electrolytic cell 2 to, optionally, generate a second gas stream that is introduced into the air inlet of the engine. This second electrolytic cell is not needed in the embodiment of figure 6, since residual/excess gas from the fuel enhancement process may be fed to the engine's air intake (after separation from the fuel/gas mixture by the separator 614).

In the embodiment of figure 1 , any enriched fuel that is provided to the fuel injector 8 but is not used in the engine 9 is returned to the fuel tank 13. In the embodiment of figure 6, however, any enriched fuel that is provided to the fuel injector 609 but is not used in the engine 600 is returned to the fuel enrichment chamber 605, thereby helping to achieve maximum saturation of the fuel. Moreover, if any fuel/gas mixture should be emitted from the fuel enrichment chamber 605 in order to relieve pressure in the fuel enrichment chamber 605, the gas component of this mixture is separated in the separator 614 and is passed to the air intake of the engine where it is burnt. (While the gas component of the mixture may in principle be vented to atmosphere, it is preferable for as much as possible of the gas to be burnt in the air intake of the engine.) Thus, no gas containing hydrogen and oxygen is introduced into the fuel tank.

It should be noted that modifications may be made to the embodiment of figure 6. For example, as with the embodiment of figure 1 , the invention is not limited to use of an electrolytic cell to generate the gas stream containing hydrogen and oxygen. The HHO generator 601 may therefore be any suitable source of a gas stream containing hydrogen and oxygen such as, for example, a source of stored hydrogen and a source of stored oxygen as described above. Moreover, although figure 6 shows a single generator to generate the gas stream containing hydrogen and oxygen in principle there could be separate generators/sources of hydrogen and oxygen, with the output from the hydrogen generator/source being combined with the output from the oxygen generator/source, or even with hydrogen gas and oxygen gas being fed separately into the enrichment chamber.

Figure 7 shows a possible control system for the fuel enrichment system of figure 6. This system comprises an ECU (electrical control system) 701 that is separate from, but communicates with, the main ECU 21 of the engine (which corresponds to the ECU 21 of figure 1 ); this makes the system of figure 6 easier to retro-fit to an existing engine since the main ECU 21 of the engine does not require significant modification. (Similarly, the system of figure 1 may be provided with a system ECU that is separate from, but communicates with, the main ECU 21 of the engine to make the system of figure 1 easier to retro-fit to an existing engine. Conversely the system of figure 6 could in principle be controlled by the main ECU 21 of the engine.)

The power for the fuel enrichment system may be derived from a battery 702 (for example a vehicle battery if the system is applied to a vehicle) or from any other suitable power source (for example the alternator (not shown) of a vehicle if the system is applied to a vehicle).

Power from the battery 702 or other power source is fed to the HHO generator 601 via a generator control 706. Figure 7 shows the generator control embodied as a relay for convenience of explanation. As is known, as relay is a device in which the main current path through the relay is either open or closed depending on the voltage or current applied between control inputs of the relay. In figure 7 the power line from the battery, or other power supply, to the H HO generator is shown as passing through the main current path of the relay. The control inputs of the relay are coupled between the main current path through a safety control 707 and earth - so that the generator control turns the HHO generator 601 On or Off depending on the output of the safety control 707.

Figure 7 shows the safety control 707 also embodied as a relay for convenience of explanation. In the preferred embodiment shown in figure 7 a control input of the relay forming the safety control is coupled to the pressure switches 703, 704 - so that, if the pressure in the fuel enrichment chamber 605 and/or the electrolyte tank 603 becomes too high the associated pressure switch will switch and cause the state of the main current path through the relay forming the safety control 707 to change, and thereby change the voltage applied to the control inputs of the relay forming the generator control 706 - and so tu rn O FF the H HO generator 601 . When the pressure in the fuel enrichment chamber 605 and/or the electrolyte tank 603 drops, the associated pressure switch will switch back and the HHO generator will restart.

The main current path through the safety control 707 is between the system ECU 701 and the control input of the generator control. The safety control is able to shut the HHO generator off if the pressure in the fuel enrichment chamber 605 and/or the electrolyte tank 603 becomes too high.

The system ECU may have a control facility that can be used to control (or limit) the rate of delivery of the hydrogen gas and oxygen gas by varying the current through a parallel resistor circuit (not shown).

The main current path between the system ECU and the control input of the generator control preferably also passes through a run control 708. Figure 7 shows the run control 708 also embodied as a relay for convenience of explanation. A control input of the relay forming the run control is coupled to a low oil pressure sensor/switch 709 provided on the engine 600. Thus, if the oil pressure in the engine 600 falls to a predetermined level (which may indicate a fault in the engine), the output from the low oil pressure sensor/switch 709 will make the main current path through the run control go open circuit, and the resultant change in the control input to the generator control will cause the HHO generator to shut off.

The ECU 702 of the fuel enrichment system may be controlled by the vehicle's ignition switch 71 1 , where the system is provided in a vehicle, to ensure that the fuel enrichment system is Off unless the vehicle's user has turned the ignition switch On. Moreover, the signal from the ignition switch may pass through a user control, such as switch 714, so that a user can select whether the fuel enrichment system is On or Off. An indicator, such as light 713, may be provided to indicate to the user that the fuel enrichment system is On - in the system of figure 7 the light 713 will only be illuminated if the vehicle ignition is On and the user has selected the fuel enrichment system via the user control 714.

The control system of figure 7 preferably has a fuse box 710, or other component that provides protection against excessive current or voltage.

The control system of figure 7 also preferably includes has a pump control 705. Figure 7 shows the pump control 705 embodied as a relay for convenience of explanation. In figure 7 the power line from the battery, or other power supply, to the fuel pump 607 is shown as passing through the main current path of the relay. A control input of the relay is coupled to the float switch 605a in the fuel enrichment chamber 605, so that the fuel pump 607 may be controlled to be ON or OFF depending on the level of fuel in fuel enrichment chamber 605.

The control system of figure 7 may optionally include one or more further indicators to provide an operator/user with information about the operating state of the fuel enrichment system. As one example, figure 7 shows a low water indicator 712, which be a light, which receives an input from the float switch 616a of the water tank 616 - so that the user is informed when the level of water in the tank falls to a low level. Figure 7 shows the pump control 705, the generator control 706, the safety control 707 and the run control 708 embodied as discrete relays. The control system is not limited to this, however, and may be implemented using any suitable control circuits such as, for example, integrated circuits, or may alternatively be implanted in software, for example under the control of a processor or micro-processor.

Figure 8 is a block flow diagram showing principal steps of a process according to one embodiment of the invention.

At step 801 hydrogen gas and oxygen gas are generated. Step 801 may comprise generating a gas stream that contains hydrogen gas and oxygen gas, or it may comprise generating a gas stream that contains hydrogen gas and a separate gas stream that contains oxygen gas. Step 801 may comprise generating a gas stream that contains hydrogen gas and oxygen gas in an electrolytic process from water in an electrolytic cell.

At step 802 a liquid hydrocarbon fuel is contacted with the hydrogen gas and oxygen gas under a pressure greater than atmospheric pressure such that at least some of the hydrogen gas and at least some of the oxygen gas is introduced into the hydrocarbon fuel to produce an enriched hydrocarbon fuel. Step 802 may for example comprise contacting the liquid hydrocarbon fuel with the first gas stream under a pressure of 1.1 bar or more, or under a pressure of 2 bar or more.

At step 803 the enriched hydrocarbon fuel is delivered to an internal combustion engine.

Optionally at step 804 the enriched hydrocarbon fuel may be heated to a temperature of at least 50 °C, before being passed to the internal combustion engine. The enriched hydrocarbon fuel may also be subjected to a magnetic field at the same time as it is heated to a temperature of at least 50 °C.

Examples

Example 1 - a 2.4 litre diesel car, standard manufacturer's configuration In the standard configuration, the above vehicle will return, on average, 42 mpg at an average speed of 60 mph. This equates to a fuel usage of 1 .43 gallons per hour, or 6.5 litres per hour. The average flow rate of the diesel into the engine is 0.1 1 litres/min.

A standard laboratory built dry cell will return 1 .5 litres/min of Hydrogen and Oxygen split in the ratio 2: 1 i.e. 1 litre of hydrogen per minute and 0.5 litres of Oxygen per minute at 15 Amps.

Two dry cells used in the configuration described above are configured to produce 3 litres/minute of gas. 1 .5 litres is passed through the fuel enhancement device per minute, compressed to 3.5 bars into the diesel fuel to displace nitrogen gas and saturate the fuel at approximately 3 bars. The fuel/vapour residual gas is taken into the air intake where it is mixed with the 1 .5 litres of purified gas from the second dry cell and finally into the combustion chamber where it is mixed with the enhanced diesel prior to ignition.

The engine in this configuration will give an increase in mpg of at least 43% (18mpg), with a corresponding decrease in carbon footprint. The NOx output is reduced to levels approaching zero. The particulates are reduced to levels approaching zero.

Example 2 - a 4.0 litre petrol Jeep, standard manufacturer's configuration

In the standard configuration, the above vehicle will return, on average, 15 mpg at an average speed of 60 mph. This equates to a fuel usage of 4.0 gallons per hour, or 18.2 litres per hour. The average flow rate of the diesel into the engine is 0.30 litres/min.

A standard laboratory built dry cell is configured to produce 2.0 litres/min of Hydrogen and Oxygen split in the ratio 2:1 , i.e. 1 .34 litres of hydrogen per minute and 0.66 litres of Oxygen per minute at 20 Amps.

Two dry cells are used in this instance to produce 4.0 litres/minute of gas. 2.0 litres are passed through the fuel enhancement chamber per minute, compressed to 3.5 bars into the petrol to displace nitrogen gas and saturate the fuel at approximately 3 bars. The fuel/vapour residual gas is taken into the air intake where it is mixed with the 2.0 litres of purified gas from the second dry cell and finally into the combustion chamber where it is mixed with the enhanced fuel prior to ignition.

The engine in this configuration will give an increase in mpg of at least 30% (4.5 mpg), with a corresponding decrease in carbon footprint. The NOx output is reduced to levels approaching zero.

Example 3 - a 10.5 litre diesel truck, standard manufacturer's configuration

In the standard configuration, the above vehicle will return, on average, 6.7 mpg at an average speed of 40 mph. This equates to a fuel usage of 5.97 gallons per hour, or 27.2 litres per hour. The average flow rate of the diesel into the engine is 0.45 litres/min.

In this case larger volumes of gas are required, necessitating the use of pairs of dry cells in parallel. For the above example, six dry cells, in two groups of three, would be run at 15 - 20 Amps, to give 9.0 - 10.0 litres/min of Hydrogen and Oxygen split in the ratio 2:1 i.e. 6.0 litres of hydrogen per minute and 3.0 litres of Oxygen per minute at -15 Amps.

4.5 litres are passed through the fuel enhancement chamber per minute, compressed to 3.5 bars into the petrol to displace n itrogen gas and saturate the fuel at approximately 3 bars. The fuel/vapour residual gas is taken into the air intake where it is mixed with the 4.5 litres of purified gas from the second dry cell and finally into the combustion chamber where it is mixed with the enhanced fuel prior to ignition.

The engine in this configuration will give an increase in mpg of at least 30% (2.0 mpg), with a corresponding decrease in carbon footprint. The NOx output is reduced to levels approaching zero. The particulates are reduced to levels approaching zero.

In the embodiment described above the effect of compressing the hydrogen and oxygen into the fuel is fourfold:

1/ Some Hydrogen and Oxygen is dissolved into the hydrocarbon fuel itself, causing partial saturation; 21 Dissolved impurities such as nitrogen are forced OUT of solution by the incoming gas thus preventing any reaction during the combustion process that leads to NOx formation;

3/ The undissolved gas carries heavy fuel vapour with it as it continues on its' journey to the engi ne i n let man ifold , some of wh ich is retai ned by the semi-permeable membrane; and

4/ The partially saturated fuel has a reduced viscosity which leads to much finer misting on passing through the fuel injection system; this gives much better mixing with the enriched air from the air intake and thus far better burning characteristics (combustion efficiency).

The present inventors have found embodiments of the present invention will provide a number of advantages, including:

1 . increasing fuel efficiency, typically measured in mpg, for example, up to 50%, in standard combustion engines running on hydrocarbon fuels;

2. a decreased Carbon Footprint to any vehicle/device using it since its fuel consumption is decreased;

3. reducing and minimising NOx production by displacement of nitrogen from the combustion area and a more efficient combustion cycle in a contained volume;

4. red uci ng the prod uction of particu lates prod uced i n d iesel com bustion engines by increasing the efficiency of the combustion such that the combustion byproducts are almost exclusively gaseous;

5. minimising engine wear by preventing the build up of carbon deposits known to occur using standard fuel/air mixtures.

6. cleaning existing engines of their carbon deposits during the first 1000-2000 km of operation after installation, thus optimising engine conditions;

7. increasing the Service Interval required for oil changes on vehicles since no carbon contamination of the oil can occur whilst the system is running correctly;

8. the ability of the device of the present invention to system to be transferred from one vehicle to another and optimised using programmable EFI E technology;

9. minimising intrusion to other existing vehicle systems, since the device can be compact and requires minimal mechanical interfacing;

10. increasing the performance of poor grade hydrocarbon fuels such that they can be used in vehicles that they would otherwise be unsuitable for;

1 1 . the versatility of the system allowing it to be applied to a wide range of internal combustion engines and vehicles, including marine and aviation vehicles.