FUEL INJECTION SYSTEMS

Field of the Invention

The present invention relates to fuel injection systems for admitting fuel to an engine.

In one embodiment, the present invention relates to fuel injection systems for use with engines including components for the fuel injection system and to methods of operating fuel injection systems to control operation of engines to which the fuel injection system is attached, particularly engines operated under conditions of hydrogen assisted combustion using hydrogen or other components as the fuel or as one of the components of the fuel for the engine. Examples of the other components of the fuel for hydrogen assisted combustion includes water, methanol or similar, including aqueous mixtures or solutions of substances or materials, water vapour or the like.

In another embodiment of the present invention, the fuel injection system controls admission of hydrogen and/or one or more of any other components of the fuel, such as for example water, to the engine either individually, separately or in combination, at amounts that allow more efficient combustion of the fuel admitted to the engine so as to provide increased power, particularly to provide increased power without significantly increasing the amount of pollutants formed by the combustion process, including the hydrogen assisted combustion process.

In a still further embodiment of the present invention, the fuel injection system controls the admission of hydrogen and/or other component or components of the fuel either individually or in one or more different combinations in amounts that allow the ratios of the individual components of the fuel to be adjusted to achieve more efficient combustion of the engine so as to

provide increased power.

Although, the present invention will now be described with reference to various forms of the fuel injection systems, to components of the fuel injection system, and to methods of using such systems particularly involving the use of venturi or precision orifices to control the amount of hydrogen being admitted to the engine as part of the fuel mixture and to the use of various components and operating systems of the various components, it is to be noted that the present invention is not limited to the described embodiment or embodiments but rather the scope of the present invention is more extensive so as to include other fuel injection systems for engines, other methods and arrangements of operating the fuel injection systems, the use of different arrangements or components in different configurations and the use of methods and systems and arrangements in other applications, including the introduction of other substances or materials either alone or in combination whether used as fuel or fuel component or not .

Engine designers are constantly striving to increase the efficiency of their engines. The introduction of fuel to the engine is one of the parameters that can be investigated to improve the efficiency of the engine. The present invention arises out of the results obtained from the investigations into the fuel system of engines. It was thought that if better utilisation of fuel can be achieved during the combustion process of the engine, it may be possible to operate an engine more efficiently so as to produce increased power, and hopefully increase power without an increase in the emission of pollutants as products formed during combustion.

Thus, it is an aim of the present invention to provide a fuel injection system which allows fuel or one or more components of fuel to be introduced into an engine in such

a manner so as to permit more efficient operation of the engine so as to produce more power, optionally with a reduction in the emission of pollutants.

According to one aspect of the present invention, there is provided a fuel injection system capable of introducing a fuel or a fuel component into an engine, said fuel injection system comprising a first inlet for introducing a first component of a fuel and a second inlet for introducing a second component of a fuel wherein flow of the second fuel component through the second inlet is dependent upon flow of the first fuel component through the first inlet so that a predetermined amount of the second component of the fuel can be introduced in accordance with the introduction of a preselected amount of the first fuel component so as to establish and/or maintain the ratio of the first fuel component to the second fuel component in the fuel being admitted to the engine by the fuel injection system within a preselected range of ratios of the fuel components to one another.

According to a second aspect of the present invention, there is provided a method of introducing a fuel into an engine using a fuel injection system having a first inlet and a second inlet comprising the steps of introducing a first component of the fuel through the first inlet and introducing the second component of the fuel through a second inlet wherein the flow of the second fuel component through the second inlet is dependent upon or in accordance with the flow of the first fuel component through the first inlet so that a predetermined amount of the second component is introduced into the engine along with a preselected amount of the first fuel component so as to establish and/or maintain a ratio of the first component to the second component in the fuel being admitted to the engine by the fuel injection system within a preselected range of ratios of the fuel components to one another.

In one embodiment of the invention, the fuel injection system includes an arrangement so that admission of one component of the fuel or the fuel itself such as for example, hydrogen, or hydrogen containing material, such as syngas or similar, is used to admit or to control admission of another component of the fuel, such as for example, water or methanol, particularly accompanied by simultaneously atomising of the water or methanol as these components are being admitted to the engine by the fuel injection system of the present invention.

A particularly preferred form of the present invention is directed to the simultaneous admission of water and hydrogen to an engine using the first and second inlets forming a venturi arrangement in which one passage which is the passage for admitting hydrogen is in fluid communication with another passage for admitting water whereby the flow of hydrogen through the hydrogen admission passage influences the amount of flow of water through the water admission passage so that predetermined amounts of hydrogen and water are admitted to the engine for combustion within the engine.

In another preferred aspect of the invention, there is provided an apparatus and method for altering the ratio of hydrogen to water to provide more complete combustion or more efficient combustion of the engine. It is to be noted that the hydrogen can be present as hydrogen gas or as one of the components of a hydrogen containing gas, such as syngas, producer gas, town gas or the like.

Typically, the first inlet is a separate inlet to the second inlet. More typically, the two inlets are located in a spatial relationship to one another. More typically, in a spaced apart relationship. Even more typically, the first inlet and the second inlet are the one inlet or are part of the one inlet or are located spaced apart from

each other within the one inlet passage or similar.

Typically, the first component of the fuel being admitted to the engine is admitted in a first state of matter which is in the form of a liquid or a gas. More typically, the second component of the fuel being admitted to the engine is admitted in a first state of matter which is either in the form of a liquid or a gas. Even more typically, mixing or contact of the first and second fuel components causes a change of state of either the first or second or both fuel components, including a change of state from a liquid to a gas, such as for example, atomisation, vaporisation or the like.

Typically, the first and/or second components of the fuel include hydrogen, water, diesel, petrol, gasoline, alcohol, gasohol, air, oxygen, syngas, carbon dioxide, carbon monoxide, methane or the like including natural materials and synthetic materials and including combinations of two or more thereof. More typically, the two components are hydrogen and water, including water vapour. Even more typically, the two components are hydrogen in a gaseous state and water, either in a liquid state or gaseous state or both. Even more typically, the hydrogen gas atomizes the water as the water flows through the fuel injection system particularly through one of the inlets of the fuel injection system, so that water vapour and hydrogen substantially in the gaseous states are introduced into the engine.

Typically, one component of the fuel is a hydrocarbon fuel containing water, particularly amounts of water in a prearranged or preselected range, whereas the other component is hydrogen. More typically, the first component is a mixture of diesel and water. Even more typically, the first component is a mixture of diesel and atomised water, preferably a mixture of diesel emulsified with water. Even more typically, the flow of diesel

through the fuel injection system draws water into the diesel from a suitable inlet or injector of the fuel injection system to emulsify the diesel with water.

Typically, the emulsion of water and diesel is admitted to the engine through a fuel injector, such as a diesel injector, water injector, combination injector or the like. More typically, there is a fuel or diesel injector associated with each cylinder of the engine.

Typically, the hydrogen is admitted through a hydrogen injector. More typically, the hydrogen is mixed with air prior to being injected into the engine. Even more typically, there is a hydrogen injector located at or near to each inlet port of the engine.

Typically, the injector for admitting one component of the fuel is a different or separate injector to the injector for admitting the other component of the fuel . In one embodiment there is an injector for each individual component of the fuel. In another embodiment, the one injector introduces more than one component of the fuel. More typically, the injector is a compound or complex injector. Even more typically, the injector is a co- injector, or double injector or a triple injector or the like for injecting measured amounts of two or more individual components into the engine, particularly measured or metered amounts of fuel, hydrogen, water and methanol either separately or in combinations .

Typically, the co-injector is a coaxial injector, a concentric injector, an annular injector, a venturi injector, a double venturi injector, a side by side injector or the like, More typically, there is a first orifice, nozzle, opening, jet, spray or the like centrally located and a second orifice, nozzle, spray, opening, jet or the like located near to, adjacent, contiguous, around, surrounding or the like the first orifice such as for

example, being co-axial or concentric, or located to one side of the first orifice or to one or more sides of the first orifice. More typically, there can be more than one first orifice located in spaced apart locations and/or there can be more than one second orifices located in spaced apart locations from the central orifice or orifices or from each of the second orifices. Typically, the two orifices are within the one body.

Typically, the first orifice or orifices are in fluid communication with the second orifice or orifices so that movement of fluid through the first orifice or orifices causes flow of fluid through the second orifice or orifices. More typically, the injector has two, three, four or more passages or passageways. Even more typically, the passages or passageways are interconnected to each other, preferably inclinedly interconnected together to form a venturi or other precision orifice. Even more typically, at least one and preferably at least two of the passageways have inclined wall portions for assisting in flow of material through the passageway.

Typically, the injector has a common opening, orifice, venturi, aperture, chamber, cavity, or the like. More typically, the individual passages or passageways are joined to the common opening so that flow of fluid along one passageway to the common opening causes, flow in one or more of the other passageways, preferably corresponding, related or controlled flow.

Typically, the hydrogen flow and the water flow are individually metered. More typically, the fuel system includes a common rail diesel fuel system. More typically, there are two common rails for the diesel engine, one for hydrogen, the other for water. Even more typically, the common rail for hydrogen and the common rail for water are connected to the same injector which is used to deliver measured amounts of both hydrogen and

water individually controlled, and optionally to atomise the water as it passes through and/or out of the injector.

Typically, the co-injector is a threaded injector having a threaded nozzle design or is a slot nozzle design. The co-injector can take any suitable shape, size, configuration, orientation or the like. The first orifice or orifices can be of any size, shape or form as can be the second orifice or orifices.

It is to be noted that the word ^λ fuel' as used herein refers to the fuel itself or to any one or more components of the fuel, including the hydrocarbon or major constituent of the fuel alone, or to the fully formulated fuel containing all additives, water and hydrogen, or to any combination of one or more components of the fuel . Further, reference to diesel is for ease of understanding and clarity of expression and it not meant to be limiting in any way by being restricted to diesel fuel only but includes all types of fuel, including hydrocarbon and non- hydrocarbon fuels, such as for example, natural, blended or synthetic fuels, petrol, gasoline, diesel, bio-diesel, syngas, alcohol based fuels, gasohol or the like..

The present invention will now be described by way of example with reference to the accompanying drawings in which:

Figure 1 is a schematic flow diagram of one form of the fuel injection system of the present invention showing the hydrogen injectors located at the inlet ports of the engine;

Figure 2 (a) is a schematic cross sectional view of one version of one component of another form of the fuel injection system of the present invention in the form of a co-injector for injecting hydrogen and water;

Figure 2 (b) is a schematic cross sectional view of another version of the co-injector of the fuel injection system of the present invention;

Figure 3 is a schematic block diagram of another embodiment of the fuel injection system of the present invention showing a flow control sensor; and

Figure 4 is a schematic view of another embodiment of the fuel injection system of the present invention for emulsifying diesel with water.

In Figure 1, there is shown schematically one embodiment of the fuel injection system of the present invention. In this embodiment, generally denoted as 2 there is an intake manifold 4 having three branches 6 for admitting air into an engine 10 through inlet ports 7. Typically the engine is an engine using hydrogen assisted combustion requiring the admission of hydrogen to the engine as part of the fuel either as a separate component or in combination with one or more other components. A water injection assembly 8, including a water injector, is provided in the induction system located either within or in fluid communication with the intake manifold 4 such as upstream of intake manifold 4. The purpose of the water injection assembly 8 is to inject water, methanol or other similar additive, including mixtures of two or more additives, including water, into the intake manifold 4 for use as part of the fuel for the engine. It is to be noted that the water injection assembly 8 can be any suitable type of water injector and can be located in any suitable location in the manifold or induction system. Further, it is to be noted that the water can be supplied from a mixer (not shown) located at a suitable location, such as before the location of the injector for injecting the water into the engine. Also, the water can be mixed with air, fuel, waste fuel, or other material in the mixer before being passed to and through the water injector depending upon

the specific arrangement of the fuel injection system.

A hydrogen injector 12, is located in each branch 6 of the intake manifold 4 for injecting hydrogen into intake manifold 4 after having been received from a suitable hydrogen supply or reservoir (not shown) . The hydrogen can be produced in situ or on board the vehicle using a suitable hydrogen generator, fuel cell or reformate gas generator or the like or the hydrogen can be stored in a fuel tank specially adapted to contain hydrogen that was obtained from a hydrogen filling station, such as for example in a manner similar to the supply of conventional hydrocarbon fuels such as petrol, gas, diesel or the like from a conventional filling station or service station. Additionally, the hydrogen can be mixed with air, waste fuels, inert gasses or other material or materials prior to passing through the injector into the manifold and/or the engine .

In this embodiment, the water injection assembly is operated to inject a predetermined amount of water or optionally a water containing mixture into intake manifold 4. In this embodiment, the water is mixed with waste hydrocarbons derived from the fuel being used in vaporised or liquid form. Additionally or alternatively, inert gasses can be mixed with the water or water containing mixture .

A metered amount of hydrogen is introduced into each branch of intake manifold 6 using hydrogen injector 12. The hydrogen is injected in the form of vapour and the hydrogen injectors are preferably located near the intake ports of the engine. However, the hydrogen injectors can be located anywhere in the intake manifold and/or are capable of receiving a hydrogen containing mixture from a mixer .

It is to be noted that in other embodiments, the water

injection assembly 8, typically in the form of separate water injectors, are located close to the intake ports 7 near to the location of the hydrogen injectors 12.

In operation of the various forms of the fuel injection system of the present invention, the fuel mixture can be injected into the engine in a number of different ways including the following:

One way of injecting fuel into the engine which is known as continuous flow injection, involves supplying the fuel under pressure and varying the pressure applied to the fuel behind the hydrogen injectors so as to achieve the desired fuel flow to the engine in accordance with the operating conditions of the engine. In this arrangement, the injectors are constantly open and the variation in pressure applied to the fuel alters the rate of flow of fuel to the engine and hence the amount of fuel injected into the engine since the injectors remain open substantially at all time during operation of the engine.

Another way of operating a fuel system includes pulsed injection with concurrent fuelling. In this embodiment, the fuel, including additives such as hydrogen, water and the like, is provided at a constant pressure. The injector or injectors are operated so as to periodically open and close as required thereby producing pulses of fuel corresponding to opening of the injector (s). The pulsing of the injectors is synchronous to the engine phase to maintain a balanced flow to each cylinder. In this embodiment the engine speed dictates the timing of the pulse which in turn controls the flow through the injectors and thus have the amount of fuel being injected into the engine. In this arrangement, all injectors fire simultaneously using a common signal. Such an arrangement is often referred to as port injection or bank fire injection.

A further method of operating is referred to as sequential pulsed injection. In this arrangement, the pressure applied to the fuel behind the injectors is constant and the fuel is metered through the injector by pulsing the operation of the injector to an open combination, which pulsing is synchronous to the engine speed but is applied to each injector sequentially in turn as required. The opening of the injectors is determined by the firing order of the cylinders of the engine so that each injector is opened at the required time depending upon the cycle or stroke of the engine. In this arrangement, each injector meters a fuel quantity specific to the particular port into which the injector is introducing fuel. In this arrangement, firing of the injector is linked to the intake event of the port so that the opening of the injector is temporally correlated to the intake valve event of the cylinder.

In this method of operating the injection timing occurs such that fuel is efficiently inducted into the cylinder. It is typical for a control system to time the injection such that the injector completes its pulse just as the intake valve opens or starts its pulse at a pre-defined crank angle point less than one cycle before the intake valve opening event to allow compression of the fuel prior to firing of the fuel.

An alternative term for this arrangement is sequential fuel injection (SFI) .

If an engine is to be operated using sequential fuel injection and the water injectors are located next to each individual intake port 7 along with the fuel injectors, this arrangement would require that the water injectors are fired synchronously with the engine speed and each water injector would be required to open to admit water specific to the port in accordance with opening of the corresponding intake valve. This arrangement is a

variation on the SFI technique.

It is to be noted that the difference between typical fuel injection timing and the water timing is that the fuel injectors finish their pulses as the intake valve opens. However, the introduction of water should overlap with the opening of the intake port sufficiently to allow atomized water to enter the cylinder.)

Each of the above described ways of injecting fuel is applicable to the fuel injection system of the present invention since the fuel injection system of the present invention can be adjusted or modified to operate in any of these ways depending upon circumstances, the engine or the like. Furthermore, other ways of operating are possible.

In another embodiment of the fuel injection system of the present invention, the injectors for admitting hydrogen and water separately could be combined together into a single injector for simultaneously admitting hydrogen and water, and optionally diesel fuel to the engine. One arrangement of such a dual admission injector is to arrange the ejector openings coaxially or concentrically or side by side but linked to each other so that more than one single material can be co-injected simultaneously with one or more components, such as for example, either fuel and hydrogen, water and hydrogen or water, fuel and hydrogen together. In this arrangement, the water injector could be located at the centre of the co- injection nozzle and the injector for introducing fuel or hydrogen could surround the centrally located water injector.

Further details of one form of the co-injector will now be described with reference to Figure 2 which illustrates two different forms of the co-injector, the first being a threaded nozzle design as shown in Figure 2a and the second being an injector slot nozzle design as shown in

Figure 2b. Other forms and arrangement of the co-injector are possible.

As the injectors of Figures 2a and 2b are similar, they will be described together with reference to the parts of the injector common to both, and separately where they are different. Figures 2a and 2b are schematic cross sectional views of two different forms of a compound or co-injector nozzle used for co-injecting water and hydrogen into the combustion chamber of an engine. In these forms, there is provided an injector generally denoted as 20 having an injector tip 22, terminating in a nozzle portion 24 of the injector. A first bore or passage 26 is located within injector tip 22. Passage 26 is a hydrogen feed tube for feeding metered amounts of hydrogen to the nozzle end 24 of the injector tip 22 for discharging hydrogen into the engine. Bore 26 is provided with end wall 28 leading to an opening 30 at the end of the nozzle 24. In one embodiment, end wall 28 is optionally inclined to assist in injecting hydrogen into the intake manifold and/or engine. Opening 30 is referred to as a nozzle venturi and takes the form of an aperture, cavity, bore, opening, chamber, orifice or similar.

A second bore 40 is provided adjacent first passage 26 and is a water feed tube for supplying water to the end of nozzle 24 located at the tip of injector tip 22. The end of bore 40 is provided with a connecting passage 42 which connects nozzle venturi 30 with water feed tube 40. In one form, connecting passage 42 is angularly inclined to the longitudinal axis of water feed tube 40. A water feed venturi 44 is formed at the end of the inclined connecting passage 42 to allow water exiting through venturi 44 to mix with the hydrogen exiting from hydrogen feed tube 26 through nozzle venturi 30.

Operation of this form of the nozzle will now be described. This nozzle arrangement is one way of

atomising water and hence introducing measured or predetermined amounts of water into the fuel and/or engine using the flow of hydrogen since the water feeds into the high velocity section of the hydrogen venturi 30 by the action of the flow of water.

Hydrogen is metered through the hydrogen feed tube 26 using a standard solenoid type hydrogen injector for controlling the amount of hydrogen passing through the tube. The solenoid is operated in accordance with signals received from the engine management system or similar, typically in accordance with the speed of the engine. Hydrogen injectors are very similar to liquid injectors used as fuel injectors, particularly petrol fuel injectors commonly used on most motor vehicles. The main difference between hydrogen injectors and fuel injectors is that hydrogen injectors are designed to flow a gaseous fuel instead of a liquid fuel since hydrogen is injected as a gas .

Water is metered through tube 40 using a suitable injector such as a standard methanol injector. Methanol injectors are similar to petrol injectors.

Both the water injector and hydrogen injector are fired at the same time or nearly at the same time so that the metered amounts of hydrogen and water are flowed through the nozzle simultaneously.

As the hydrogen flows through nozzle venturi 30, it draws water through the water feed tube 40 into connecting passage 42 to exit through water feed venturi 44 and hence through nozzle venturi 30 and then into the engine or manifold. The velocity of the hydrogen passing through water feed venturi 44 creates a vacuum in the venturi which atomises the water from water feed 42 as it is being dispensed through the nozzle of injector tip 22 into the engine or manifold.

The size of the nozzle venturi 30 and the water feed venturi 44 are selected according to the desired flow rates required and the particular control system being employed to provide the required hydrogen to water ratio in the fuel as well as the desired atomization of the water.

Also, the water pressure for supplying the water to water feed tube 40 may require modulation to accommodate varying ratios of water to hydrogen as required by the particular injection system being used and the characteristics for combustion required by the particular engine.

It is to be noted that the combined water and hydrogen injector can take any form or have any geometry, shape, configuration or the like that allows the flow of one component to control the flow of the other component so that the amount of other component is dependent upon the flow of the one component.

One modification of this form of the invention is that one variant of the technique would apply different pulse times for hydrogen and water to account for varying ratios between the hydrogen flow rate and the water flow rate. Also, different pressures can be applied to hydrogen and to water to adjust the amounts of each of these materials to achieve the required hydrogen to water ratio in the fuel .

By selecting a tip of the injector with a nozzle having predetermined sizes of openings, it is possible to use the flow of hydrogen through one of the openings, i.e. the nozzle venturi 30, to draw the required amount of water through the other of the openings, the water feed venturi, so that a single injector for both hydrogen and water can be used rather than requiring two separate injectors.

It is to be noted that in one embodiment the nozzle of the present invention can be a coaxial or σo-centric nozzle in which hydrogen and water are combined together prior to discharge. In another embodiment, the supply of hydrogen and the supply of water may be separate from each other but interlinked together so that the same result is achieved. In this embodiment, the supply pipe of the hydrogen is separate from the supply pipe of the water so that two common rails for a diesel engine are provided, one for the hydrogen and the other for water. In this embodiment, rather than the water and hydrogen being injected as a single stream, the water and hydrogen are injected as two separate streams. However, there is a connection between the two streams so that flow of hydrogen in one stream influences or causes the amount of water to flow in the other stream. Other variations of this include the water and hydrogen being combined before entry to the inlet port of the engine, combined at the inlet port, or introduced through the inlet port separately for mixing within the combustion chamber of the engine .

The technique of using two openings interlinked to each other as a co-venturi arrangement involving the use of a single orifice is applicable to common rail diesel injection systems or mechanical fuel injection systems.

Another embodiment of the fuel injection system of the present invention is schematically shown in Figure 3.

This embodiment of the present invention is an improvement of the fuel control system used to provide hydrogen to the engine. This embodiment requires that the fuel control system be a pressure control system rather than flow control system. The system of this embodiment employs a common method for measuring the flow of hydrogen. However, the method of the present invention for determining the flow of hydrogen utilises the measurement

of pressure and temperature of the fuel upstream of a critical flow venturi (or precision orifice) where the pressure drop across the venturi (or orifice) is greater than the subsonic turbulent flow number for the fuel . The subsonic turbulent flow number is characterised by the

Reynolds number of the fuel. As an example, the fuel flow calculation is performed for fuel at the supply tank 80 and at the flow nozzle in the mixer 82. The two measured flow values must correlate with each other. If there is a greater flow at the tank than at the nozzle, then a leak is present in the system between the tank and the nozzle or similar.

Another embodiment of the present invention is shown in Figure 4.

This embodiment involves the use of water emulsification to mix water and fuel, such as diesel. The hydrogen is provided by a suitable source, such as for example, from a hydrogen supply tank via a hydrogen mixer 70 to supply hydrogen to the intake manifold of an engine. Any form of hydrogen injector or any location of the injector can be used including the use of the injectors as described previously in this specification. As an example, the hydrogen could be supplied to the engine at the intake ports using hydrogen injectors. The hydrogen is supplied separately to the other fuel components. However, other hydrocarbon fuels in the vapour form may be added to the hydrogen stream or supply or admitted through the air induction system.

Water is supplied from a water tank 60 to a water metering system 62 which controls the amount of water that is added to the diesel fuel by simple injection or being emulsified into the diesel fuel. Water from the water metering system 62 is mixed with diesel from diesel fuel tank 64 pumped by diesel lift pump 66. The water can be introduced into the diesel in any manner. One particular

manner is introducing the water into the diesel before the high pressure pump 68. Mixing of the water and diesel prior to the high pressure pump allows the diesel injector 72 to atomise the water thereby avoiding the need to use a separate injector for the water. The use of water emulsification in diesel to introduce water and diesel in combination into an engine for mixing with hydrogen to allow hydrogen assisted combustion to take place is applicable to a wide range of fuel injection systems, such as fuel injection systems using common rail diesel injection, double common rail diesel injection, injection systems using the co-injection nozzles or combined venturi injectors or the like. When using mechanical injection, diesel high pressure pump 68 delivers fuel and water to each point directly.

It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country.

It will be understood to persons skilled in the art of the invention that many modifications may be made without departing from the spirit and scope of the invention.