WO2000040856A1

WO2000040856A1 - Fluid mixing apparatus and a method of vaporizing injected fuel

Info

Publication number: WO2000040856A1
Application number: PCT/AU2000/000001
Authority: WO
Inventors: Alan Patrick Casey
Original assignee: Split Cycle Technology Limited
Priority date: 1999-01-05
Filing date: 2000-01-04
Publication date: 2000-07-13
Also published as: TW425457B; AUPP802299A0

Abstract

A method of increasing the vaporization of liquid fuel droplets by the addition of a heated air stream (20, 15) to the flow of droplets upstream of the combining of the fuel/air mixture (13, 14) and an additional air stream (16, 17). An additional gas (19), such as hydrogen can also be added to the heated air stream (15) (fig.2). There is also defined a mixing apparatus (60) comprising a nozzle (64) in fluid communication with a source of liquid, and a gas passage (63) immediately adjacent and extending past the nozzle (64) which directs a pressurised gas past the nozzle (64). The nozzle (64) directs the liquid into the passage. There are gas valve opening and closing means (62) and nozzle opening and closing means (61), which are independently operable via non-coaxial valve movements (fig. 4).

Description

FLUID MIXING APPARATUS AND A METHOD OF VAPORIZING INJECTED FUEL

Technical Field

The present invention relates to methods and means for providing combustible mixtures which may be appropriate for internal and external combustion engines or for ignition in other environments requiring the provision of heat.

Background Art

A requirement of the present invention is the use of a device for supplying a combustible fluid which has provision for the inspiration of oxygen or a fluid mixture containing oxygen.

A fuel injector of the kind disclosed in US 5735468 and a nozzle arrangement of WO96/41685 are particularly, but not exclusively, suited for use in the present invention and the contents of those two specifications are incorporated herein by reference.

Disclosure of Invention

Throughout this specification, unless the context requires otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

In a first aspect of the present invention, a mixing of inspirated air and/or other gasses into a combustible fluid mixture as it passes through a nozzle markedly facilitates mixing with the primary expanding fluids. Openings in the region of the nozzle facilitate control of the inspirated air while a heating of that air in accord with the present invention can provide energy to be transferred to atomized droplets of combustible liquid so as to improve vaporization of those droplets. As heat is added through the heated inspirated air, its effect upon vaporization is concentrated in the region of a rich mixture without the necessity of significantly increasing the temperature of the inlet air in, say, an inlet manifold of an internal combustion engine. Typically, the inspirated air may be about 5% of the total quantity of air required for completely combusting the charge of combustible fluid. It will be appreciated that the temperature of the inlet air is critical to the mass that can be induced into, say, an internal combustion engine, so that heating of the whole inlet air supply has a negative effect on engine performance. Despite improved vaporization by raising of the inlet air temperature there will be a power output reduction in an internal combustion engine. By adding heat in accord with the present invention in the venturi region of an inspiration device associated with an injector it will be noted that the latent heat of vaporization of liquid fuel droplets ensures that the temperature of the inlet air does not rise significantly so as to detrimentally affect the efficiency of the engine.

In a preferred form, the present invention provides for inspiration of hydrogen and/or other gasses in conjunction with the heating of inspirated air. The intimate mixing of, say, hydrogen and the fuel can significantly increase the burn rate and so reduce the burn time such the there may be reductions in nitrous oxides, carbon monoxide, and particulate and hydrocarbon emissions.

In a second aspect of the present invention there is provided a variation on the injector embodiment disclosed in US 5735468. In this aspect, such an injector includes separate controls, for example, independent solenoid controls, for opening and closing respective fuel and air supply valves to supply those fluids to the injector body. In this way it is possible to vary the timed interaction between the air and fuel within the injector in order to vary its performance settings as may be required in differing applications.

Brief Description of Drawings

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

Fig 1 is a prior art injector and nozzle arrangement of Fig 7 of WO 96/41685;

Fig 2 is a schematic cross-sectional view of an arrangement demonstrating one method of operation in accord with the present invention;

Fig 3 is a cross-sectional view of a direct injection system in accord with another embodiment of the present invention;

Fig 4 is a cross-sectional view of a first embodiment of an alternate from of injector in accord with the second aspect of the present invention; and Fig 5 is a cross-sectional view of a second embodiment of an injector in accord with the second aspect of the invention.

Best Modes

The prior art arrangement of Fig 1 will not be described in detail as its operation is clearly set out in the disclosure of WO 96/41685.

The embodiment of Fig 2 shows an injector 10 supplied with compressed air line 11 and pressurized fuel line 12. Surrounding injector nozzle outlet 13 is a plenum 14 receiving secondary air and/or gases via line 15. All of the aspects so far described in relation to the Fig 2 embodiment are equivalent to what is shown in Fig 1.

The inspiration zone within plenum 14 is followed by a turbulence and mixing generator 16 having slots 17 and fitted within manifold 18. Manifold airflow feeds in and through slots 17 to combine with the air/fuel/gas mix exiting the inspiration stage.

Inspirated air and/or other gasses, such as hydrogen, are fed through line 15. Additional gas line 19 and inspiration air line 20 are coupled to line 15 with respective limiting orifice valves 21 and 22 further controlling the flow in each of those lines.

Heater 23 in air bleed line 20 raises the temperature of the inspiration air entering plenum 14 to provide improved vaporization effects to the combustible liquid droplets, as previously described. Zero regulator 24, which is adjacent to open at a predetermined detected pressure, controls the supply of gasses into line 19. Manifold pressure feedback line 25 (dotted) inputs to zero regulator 24 to provide a feedback signal for controlling regulator 24 in its supply of other gasses to line 19.

In operation of the embodiment of Fig 2, a reduced pressure zone is created in the inspiration zone of the nozzle within plenum 14 as the expanding pressurized fluid leaving injector nozzle 13 passes through a venturi type reduced area before entering mixing generator 16 within manifold 18. The zone around and prior to the venturi type restriction is formed with openings 25 to allow a flow of air and/or other gasses into the low pressure area of the nozzle to be mixed with the primary expanding gasses. That secondary air and/or gasses enter plenum 14 via line 15 and then through the openings combines with the primary and vaporized fuel gasses exiting the injector nozzle 13. By heating the secondary gas stream entering plenum 14 via line 15 and its subsequent mixing with the primary expanding gasses and droplets. Those droplets will be further vaporized by the heat addition without substantially changing the temperature of the mixed primary and secondary streams as the latent heat of vaporization of the droplets reduces the temperature of the combined primary and secondary streams as they mix before entering manifold 18.

The embodiment depicted in Fig 3 is of a direct injection arrangement. This embodiment is provided with a heater within air bleed passageway 30 supplying secondary air to plenum 14. A standard type injector 50 is shown in Fig 3 merely to provide a visual comparison between an arrangement in accord with a currently conventional direct injection arrangement as compared with an embodiment of the present invention. It will be appreciated that an additional gas line for, say, supplying hydrogen could be fitted to the embodiment of Fig 3 which, as it is now shown, is probably more typical of an immediately commercially practicable layout in accord with the present invention.

A first embodiment of a modified form of injector 60 of the second aspect of the present invention as shown in Fig 4 is formed with solenoid control 61 for opening and closing nozzle 64 metering fuel supply to the outlet nozzle 65 of injector 60 and an independently controlled solenoid 62 for metering pressurized air supply to injector 60 through air valve 63. By varying the timed interactions between fuel supply valve or nozzle 64 opening via solenoid 61 and supply of the air via operation of solenoid 62, an infinitely variable arrangement of timed interactions between the supply of fuel and air is possible. One mode of operation could be to provide the air valve 63 as constantly open during an injector operation and provide pulsing of the fuel supply through nozzle 64 via actuation of solenoid 61.

The second injector embodiment 70 of Fig 5 has solenoid 71 and biasing spring 72 controlling the operation of fuel valve or nozzle 73. Solenoid 74 in conjunction with biasing spring 75 controls the operation of air valve 76 which opens to feed pressurized air into plenum 77 and then past nozzle 73 and into and through stepped outlet nozzle 78.

It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Claims

CLAIMS:

1 A method of vaporizing liquid fuel droplets exiting from a fuel injector comprising mixing the liquid fuel droplets with a heated air stream prior to combining the resultant mixture with a further airstream to form a further mixture to be combusted.

2 A method as claimed in claim 1 wherein at least one additional gas is added to the heated air stream.

3 A method as claimed in claim 2 wherein the at least one additional gas is hydrogen.

4 A method as claimed in any one of the preceding claims wherein the further mixture is formed in a manifold of an internal combustion engine.

5 A method as claimed in any one of claims 1 to 3 wherein the further mixture is formed in a direct injection intake of an internal combustion engine.

6 A method as claimed in any one of the preceding claims wherein the heated air stream is formed as an inspirated air stream mixing with the liquid fuel droplets.

7 A method as claimed in claim 6 wherein heating means are located in the flow path of the inspirated air stream upstream of a plenum which facilitates mixing of the inspirated air and the liquid droplets.

8 A mixing apparatus comprising a nozzle in fluid communication with a source of liquid, and a gas passage immediately adjacent and extending past the nozzle as to, in use. direct a pressurized gas towards and past the nozzle, the nozzle being adapted to direct the liquid into the passage gas valve opening and closing means opens and closes the gas valve and nozzle opening and closing means opens and closes the nozzle, wherein the gas valve opening and closing means and the nozzle opening and closing means are independently operable via non-coaxial valve movements. A mixing apparatus as claimed in claim 8 wherein the valve movements are along mutually orthogonal axes.

A mixing apparatus as claimed in claim 8 or 9 wherein the gas valve and nozzle are each opened and closed via respective electronically controlled solenoids.