WO2025039076A1

WO2025039076A1 - Apparatus and method for an injection chamber in a fuel injector

Info

Publication number: WO2025039076A1
Application number: PCT/CA2024/051079
Authority: WO
Inventors: Kyle PHILIBERT-PALMER; Kory ZELLER; Alexander Kay
Original assignee: Hpdi Technology LP
Current assignee: Hpdi Technology LP
Priority date: 2023-08-18
Filing date: 2024-08-16
Publication date: 2025-02-27
Anticipated expiration: 2026-02-18
Also published as: WO2025039076A9; CN121443840A

Abstract

A fuel injector includes an injection chamber downstream from an injection valve, the injection chamber defined by an outer surface of a valve member and an inner surface of a nozzle body. A tapered portion of the outer surface of the first valve member within the injection chamber tapers radially outwardly in an axial direction relative to a longitudinal axis of the fuel injector from the injection valve to the injection passageway whereby a cross-sectional flow area in the injection chamber is greater by the injection valve compared to by the injection passageway.

Description

APPARATUS AND METHOD FOR AN INJECTION CHAMBER IN A FUEL INJECTOR

Technical Field

[0001] The present application relates to an injection chamber in a fuel injector, and particular injection chambers downstream from a fuel injection valve.

[0002] The following discussion of the background to the invention is intended to facilitate an understanding of the present invention only. It should be appreciated that the discussion is not an acknowledgement or admission that any of the material referred to was published, known or part of the common general knowledge of the person skilled in the art in any jurisdiction as at the priority date of the invention.

[0003] Ever since the first internal combustion engine was introduced, continuous development of technology has significantly improved internal combustion engine performance in terms of fuel economy and emissions. Most of the readily recognizable solutions to these performance metrics have been identified and implemented. Any further developments that improve performance are more difficult to ascertain, yet many may still provide significant improvements. Other viable technologies that can be employed as powerplants used in locomotion, such as in fuel cell or electric vehicles, have motivated a new generation of technical improvements with regard to performance keeping the internal combustion engine as the preferred powerplant in many applications.

[0004] The introduction of fuel into the combustion chambers of internal combustion engines plays a crucial role in the fuel economy and emissions associated with the ignition and combustion of that fuel. Evolving emission standards and fuel economy expectations are placing ever increasing requirements for improved combustion characteristics.

[0005] The state of the art is lacking in techniques for injection chambers in fuel injectors introducing a fuel into a combustion chamber of an internal combustion engine.

[0006] An improved fuel injector includes a nozzle body having an inner surface, the inner surface comprising a valve seat. There is a first valve member configured to reciprocate along a longitudinal axis of the fuel injector within the nozzle body. The first valve member has an outer surface, and the outer surface includes a sealing surface engageable with the valve seat of the nozzle body. The sealing surface of the first valve member and the valve seat of the nozzle body form a first injection valve. The first valve member is movable between a closed position where the sealing surface abuts the valve seat whereby the first injection valve is closed and an open position where the sealing surface is spaced apart from the valve seat whereby the first injection valve is open. An injection chamber is downstream from the first injection valve and is defined by the outer surface of the first valve member and the inner surface of the nozzle body. The nozzle body further includes an injection passageway extending from the injection chamber through the nozzle body to an outer surface of the nozzle body. A tapered portion of the outer surface of the first valve member within the injection chamber tapers radially outwardly in an axial direction relative to the longitudinal axis from the first injection valve to the injection passageway whereby a cross-sectional flow area in the injection chamber is greater by the first injection valve compared to by the injection passageway.

[0007] In some embodiments, the tapered portion of the outer surface in the injection chamber tapers linearly. In some embodiments the tapered portion of the outer surface in the injection chamber is a concave surface. In some embodiments the cross-sectional flow area in the injection chamber decreases linearly from the first injection valve towards the injection passageway.

[0008] A side portion of the inner surface of the nozzle body in the injection chamber can extend longitudinally from the first injection valve to the injection passageway. The side portion of the inner surface of the nozzle body within the injection chamber can taper radially inwardly in the longitudinal direction from the first injection valve to the injection passageway.

[0009] The injection chamber further includes a ceiling portion of the outer surface of the first valve member extending between the tapered portion of the outer surface of the first valve member and the sealing surface of the first valve member. An angle between the ceiling portion and the sealing surface of the first valve member can be between a range of 5 degrees and 20 degrees. [0010] In some embodiments, a valve seat angle is in a range of 60 degrees and 100 degrees. In some embodiments, a tapered portion angle is in a range of 10 degrees and 30 degrees. In some embodiments, an injection passageway angle is in a range of 10 degrees and 30 degrees. In some embodiments, the valve seat angle is in a range of 85 degrees and 95 degrees, the tapered portion angle between a range of 17 degrees and 23 degrees; and the injection passageway angle is in a range of 18 degrees and 24 degrees.

[0011] The valve seat in the nozzle body and the sealing surface on the first valve member can be annular. Similarly, the injection chamber can be an annular chamber.

[0012] In some embodiments, the fuel injector is a dual-fuel injector that injects a first fuel through the first injection valve and the first valve member is hollow including an inner surface having a valve seat. The dual-fuel injector can further include a second valve member disposed within the first valve member and configured to reciprocate longitudinally therein. The second valve member has a sealing surface. The sealing surface of the second valve member and the valve seat of the first valve member can form a second injection valve. The second valve member can be movable between a closed position where the sealing surface of the second valve member abuts the valve seat of the first valve member whereby the second injection valve is closed and an open position where the sealing surface of the second valve member is spaced apart from the valve seat of the first valve member whereby the second injection valve is open. A second injection chamber can be downstream from the second injection valve. The second injection chamber can be defined by the outer surface of the second valve member and the inner surface of the first valve member. The first valve member can further include an injection passageway extending from the second injection chamber through the first valve member to the outer surface of the first valve member.

[0013] In some embodiments, the fuel injector injects a gaseous fuel. The gaseous fuel can be selected from the list containing ammonia, biogas, butane, ethane, hydrogen, liquefied petroleum gas, methane, natural gas, propane, and mixture of two or more of these gaseous fuels.

[0014] An internal combustion engine includes a combustion chamber and a fuel injector like the improved fuel injector described above configured to directly inject a fuel into the combustion chamber. In an exemplary embodiment, the fuel injector can be actuated to inject the fuel after 120 crank angle degrees during the compression stroke. In some embodiments, the fuel injector can be actuated to inject the fuel before 120 crank angle degrees during the compression stroke. The fuel can be a gaseous fuel. The fuel injector can be the dual-fuel injector described above. The dual-fuel injector can inject a first fuel into the combustion chamber through the first injection valve and the injection passageway in the nozzle body, and the dual-fuel injector can inject a second fuel into the combustion chamber through the second injection valve and the injection passageway in the first valve member. In some embodiments, the first fuel is a gaseous fuel, and the second fuel is a liquid fuel. The first fuel can be selected from the list containing ammonia, biogas, butane, ethane, hydrogen, liquefied petroleum gas, methane, natural gas, propane, and mixture of two or more of these gaseous fuels; and the second fuel can be selected from the list containing diesel fuel, dimethyl ether (DME), kerosene, and mixtures of two or more of these fuels.

[0015] An improved method for injecting fuel with a fuel injector includes providing a nozzle body comprising an inner surface, the inner surface comprising a valve seat; providing a first valve member configured to reciprocate along a longitudinal axis of the fuel injector within the nozzle body, the first valve member comprising an outer surface, the outer surface comprising a sealing surface engageable with the valve seat of the nozzle body; forming a first injection valve with the sealing surface of the first valve member and the valve seat of the nozzle body, the first valve member movable between a closed position where the sealing surface abuts the valve seat whereby the first injection valve is closed and an open position where the sealing surface is spaced apart from the valve seat whereby the first injection valve is open; providing an injection chamber downstream from the first injection valve, the injection chamber defined by the outer surface of the first valve member and the inner surface of the nozzle body; providing in the nozzle body an injection passageway extending from the injection chamber through the nozzle body to an outer surface of the nozzle body; and tapering a tapered portion of the outer surface of the first valve member within the injection chamber radially outwardly in an axial direction relative to the longitudinal axis from the first injection valve to the injection passageway whereby a cross-sectional flow area in the injection chamber is greater by the first injection valve compared to by the injection passageway.

[0016] In some embodiments, the fuel injector is a dual-fuel injector that injects a first fuel through the first injection valve, and the first valve member is hollow and includes an inner surface having a valve seat. The method further includes providing a second valve member disposed within the first valve member and configured to reciprocate longitudinally therein, the second valve member comprising a sealing surface; forming a second injection valve with the sealing surface of the second valve member and the valve seat of the first valve member, the second valve member movable between a closed position where the sealing surface of the second valve member abuts the valve seat of the first valve member whereby the second injection valve is closed and an open position where the sealing surface of the second valve member is spaced apart from the valve seat of the first valve member whereby the second injection valve is open; providing a second injection chamber downstream from the second injection valve, the second injection chamber defined by the outer surface of the second valve member and the inner surface of the first valve member; providing in the first valve member further an injection passageway extending from the second injection chamber through the first valve member to the outer surface of the first valve member.

[0017] An improved fuel injector includes a nozzle body having an injection passageway that extends from an inner surface to an outer surface of the nozzle body and a valve seat on the inner surface thereof. A valve member is movable along a longitudinal axis of the fuel injector. There is an injection valve including the valve seat and the valve member. The injection valve is closed when the valve member abuts the valve seat, and the injection valve is open when the valve member is spaced apart from the valve seat. In some exemplary embodiments, the valve member includes a channel recessed in an outer surface of the valve member. An injection chamber downstream from the injection valve is formed between the outer surface of the valve member in the channel and the nozzle body. The channel moves upwardly relative to the injection passageway when the injection valve is opened whereby the channel guides the fuel from the injection valve when open towards the injection passageway.

[0018] The injection passageway includes an inlet orifice. In some embodiments, the channel extends longitudinally and aligns angularly with the inlet orifice with respect to the longitudinal axis of the fuel injector. The fluted channel can be tapered in a downstream direction. The channel can include a first sidewall and a second sidewall that extend on opposite sides of the channel and a backwall between the first and second sidewalls. The first and second sidewalls can slope towards each other in a downstream direction. The backwall can slope radially outwardly in a downstream direction. The fluted channel can include a closed end downstream from the injection valve moveable when the injection valve opens. A contour of the closed end can match a contour of the injection passageway. A portion of the closed end adjacent the nozzle body can be below a bottom of the inlet orifice of the injection passageway when the injection valve is closed. The closed end can move longitudinally upwards relative to the inlet orifice when the injection valve opens. The portion of the closed end adjacent the nozzle body can be near to or align with the bottom of the inlet orifice when the injection valve is open. In some embodiments, the injection passageway is tapered outwardly in a downstream direction. The injection passageway further includes an outlet orifice. In some embodiments, a cross-sectional flow area of the injection passageway converges from the inlet orifice towards a point between the inlet and outlet orifices, and then diverges towards the outlet orifice. A channel inlet of the channel can be below the valve seat when the injection valve is open. The fuel injector can include an annular space around the valve member downstream from the injection valve and upstream of the channel. In some embodiments, a mass flow of fuel from the injection valve when open enters the channel inlet flowing within 30 degrees of a parallel to the longitudinal axis of the fuel injector. The valve seat can be disposed more radially outwardly than the fluted channel with respect to the longitudinal axis of the fuel injector. In some embodiments, fuel enters the fluted channel substantially from above. The fuel injector can further include a match fit between the valve member and the nozzle body around the channel and downstream from the injection valve.

[0019] There is an improved injection chamber for a fuel injector including a nozzle body having an injection passageway that extends from an inner surface to an outer surface of the nozzle body and a valve seat on the inner surface thereof. A valve member is movable along a longitudinal axis of the fuel injector. An injection valve includes the valve seat and the valve member. The injection valve is closed when the valve member abuts the valve seat, and the injection valve is open when the valve member is spaced apart from the valve seat. The injection chamber includes a channel recessed in an outer surface of the valve member. The injection chamber can be formed between the channel and the nozzle body, such that the channel moves upwardly relative to the injection hole when the injection valve is opened whereby the channel guides the fuel from the injection valve in the open position towards the injection passageway.

[0020] The accompanying drawings, which are incorporated into and constitute a part of the specification, illustrate specific embodiments of the apparatus, systems, and methods and, together with the general description above, and the detailed description of the specific embodiments, serve to explain the principles of the apparatus, systems, and methods. [0021] FIG. 1 is a cross-sectional, partial schematic view of a nozzle portion of a fuel injector with a first injection valve and a second injection valve shown in the closed position according to an embodiment.

[0022] FIG. 2 is a cross-sectional, partial schematic view of the nozzle portion of the fuel injector of FIG. 1 with the first injection valve shown in an open position and the second injection valve shown in the closed position.

[0023] FIG. 3 is a cross-sectional, partial schematic view of the nozzle portion of the fuel injector of FIG.1 illustrating a valve seat angle, a tapered surface angle, and an injection passageway angle.

[0024] FIG. 4 is a cross-sectional, partial schematic view of the nozzle portion of the fuel injector of FIG.1 illustrating detail sections.

[0025] FIG. 5 is a cross-sectional, partial schematic view of detailed section A of FIG. 4 showing an injection chamber with a fuel inlet orifice to an injection passageway.

[0026] FIG. 6 is a cross-sectional, partial schematic view of detailed section B of FIG. 4 showing an injection chamber and an injection passageway.

[0027] FIG. 7 is a cross-sectional, partial schematic view of the nozzle portion of the fuel injector of FIG.2 illustrating detail sections.

[0028] FIG. 8 is a cross-sectional, partial schematic view of detailed section C of FIG. 7 showing an injection chamber with a fuel inlet orifice to an injection passageway.

[0029] FIG. 9 is a cross-sectional, partial schematic view of detailed section D of FIG. 7 showing an injection chamber and an injection passageway.

[0030] FIG. 10 is a cross-sectional, partial schematic view of a combustion chamber of an internal combustion engine employing the fuel injector of FIG. 1.

[0031] FIG. 11 is a partial perspective view of a nozzle portion of a fuel injector according to another embodiment showing a nozzle body in split cross-section along with a first valve member having fluted channels. The first valve member is shown in an open, lifted position relative to the nozzle body on a left hand side and the first valve member is shown in a closed, seated position relative to the nozzle body on a right hand side.

[0032] FIG. 1 lb is a partial perspective view of a nozzle portion of a dual fuel injector according to an embodiment showing a second, inner valve member slidably received within a first, outer valve member.

[0033] FIG. 12 is a cross-sectional view of the nozzle portion of FIG. 11 showing a first injection valve in a closed position.

[0034] FIG. 13 is a cross-sectional view of the nozzle portion of FIG. 11 showing a first injection valve in an open position.

[0035] FIG. 14 is a detailed, cross-sectional view of an injection chamber of the nozzle portion of FIG. 11.

[0036] FIGS. 15a-d are cross-sectional views of various injection passageway geometries employed with the fuel injector nozzles disclosed herein depending on for example fuel injector configuration, type of fuel, and engine system arrangement. FIG. 15a shows a straight passageway with a substantially constant cross-sectional area along its longitudinal length. FIG. 15b shows an outwardly tapering injection passageway. FIG. 15c shows a laval shaped injection passageway and FIG. 15d shows an inwardly tapering injection passageway.

[0037] FIG. 16a is a partial perspective view of the nozzle portion of the fuel injector of FIG.1 showing one of the disclosed injection passageway geometries (outwardly tapering injection passageway).

[0038] FIG. 16b is a computational fluid dynamics negative partial perspective view for visualizing volume of injection chamber of FIG. 16a along with a negative perspective view of an outwardly tapering injection passageway.

[0039] FIG. 17a is a computational fluid dynamic rendering of a negative partial perspective view for visualizing volume (dark grey) of injection chamber of FIG. 11 along with a negative perspective view of a straight injection passageway. [0040] FIG. 17b is a computational fluid dynamic rendering of a negative partial perspective view for visualizing volume of injection chamber of FIG. 11 along with a negative perspective view of an outwardly tapering injection passageway.

[0041] FIG. 18 is a graph showing relative injection chamber volumes for four different injection chamber designs.

[0042] FIG. 19 is a graph showing the percent change of mass flow, velocity, and injection chamber (sac) volume compared to a baseline injector having injection chamber 200 design with straight injection passageways.

Detailed Description

[0043] Various features may be grouped together in exemplary embodiments for the purpose of streamlining the disclosure, but this method of disclosure should not be interpreted as reflecting an intention that any claimed embodiment requires more features than are expressly recited in a corresponding claim. Rather, inventive subject matter may lie in less than all features of a single disclosed exemplary embodiment or may combine features from different figures or different embodiments. Thus, the appended claims are hereby incorporated into the detailed description, with each claim standing on its own as a separate disclosed embodiment. However, the present disclosure shall also be construed as implicitly disclosing any embodiment having any suitable set of one or more disclosed or claimed features (i.e., a set of features that are neither incompatible nor mutually exclusive) that appear in the present disclosure or the appended claims, including those sets that may not be explicitly disclosed herein or disclosed in a single figure or embodiment. Conversely, the scope of the appended claims does not necessarily encompass the whole of the subject matter disclosed herein.

[0044] Throughout the specification and claims, the following terms take the meanings explicitly associated herein, unless the context clearly dictates otherwise. The phrases “in some embodiments” and “in an exemplary embodiment,” as used herein do not necessarily refer to the same embodiment(s), though it may. Furthermore, the phrase “in other embodiments,” as used herein does not necessarily refer to a different embodiment, although it may. Thus, as described below, various embodiments of the invention may be readily combined, without departing from the scope of the invention.

[0045] Referring to the figures and first to FIG. 1, there is shown fuel injector 10, and more particularly a nozzle portion 20 of a dual-fuel injector that protrudes into a combustion chamber of an internal combustion engine. Fuel injector 10 includes nozzle body 30, first valve member 40, and second valve member 50, which are concentrically disposed around longitudinal axis 60 of the fuel injector. Nozzle body 30 and first valve member 40 are hollow, and in some embodiments, second valve member 50 may also be hollow although this is not a requirement. Nozzle body 30 includes inner surface 70 and outer surface 80, first valve member 40 includes inner surface 90 and outer surface 100, and second valve member 50 includes outer surface 110 in the illustrated embodiment. First and second valve members 40 and 50, respectively can be actuated for movement independently and separately from each other. First valve member 40 is configured to selectively reciprocate along longitudinal axis 60 of fuel injector 10. Similarly, second valve member 50 is also configured to selectively reciprocate along longitudinal axis 60 of fuel injector 10. When the first valve member 40 is actuated to reciprocate, it automatically causes second valve member 50 to move with the first valve member along longitudinal axis 60. When second valve member 50 is actuated to reciprocate (and not by movement of first valve member 40), it does not cause first valve member 40 to move along with. Suitable actuation technologies can be employed to actuate first and second valve members 40 and 50, respectively depending upon the application. In some embodiments, the first and second valve members are actuated by hydraulic forces. In some embodiments, the first and second valve members are actuated by mechanical forces, such as by a piezoelectric actuator. In some embodiments, the first and second valve members are actuated by electromagnetic forces.

[0046] First injection valve 120 is formed between nozzle body 30 and first valve member 40 and is shown in a closed position in FIG. 1 and an open position in FIG. 2. More particularly, with reference to FIG. 2, first injection valve 120 includes valve seat 130 on inner surface 70 of nozzle body 30 and sealing surface 140 on outer surface 100 of first valve member 40. In the closed position, sealing surface 140 abuts valve seat 130, and in the open position sealing surface 140 is spaced apart from valve seat 130 in the axial direction along longitudinal axis 60. In some embodiments such as the illustrated embodiment, valve seat 130 and sealing surface 140 are annular thereby making first injection valve 120 an annular valve. [0047] Second injection valve 150 is formed between first valve member 40 and second valve member 50 and is shown in a closed position in both FIGS. 1 and 2. More particularly, with reference to FIG. 2, second injection valve 150 includes valve seat 160 on inner surface 90 of first valve member 40 and sealing surface 170 on outer surface 110 of second valve member 50. In the closed position, sealing surface 170 abuts valve seat 160, and in the open position (not shown) sealing surface 170 is spaced apart from valve seat 160 in the axial direction along longitudinal axis 60. In some embodiments such as the illustrated embodiment, valve seat 160 and sealing surface 170 are annular thereby making second injection valve 150 an annular valve.

[0048] Returning to FIG. 1, fuel injector 10 includes fueling chamber 180, formed between nozzle body 30 and first valve member 40 upstream of first injection valve 120, and fueling chamber 190, formed between first valve member 40 and second valve member 50 upstream of second injection valve 150. Fueling chambers 180 and 190 can also be referred to as plenums. In some embodiments, fueling chamber 180 is in fluid communication with a first fuel inlet (not shown) of fuel injector 10 to receive a first fuel and fueling chamber 190 is in fluid communication with a second fuel inlet (not shown) of the fuel injector to receive a second fuel. In some embodiments, fueling chambers 180 and 190 can receive the same fuel through the first and second fuel inlets, which can be either the first fuel or the second fuel. In some embodiments, fueling chambers 180 and 190 are in fluid communication with a common fuel inlet to receive the same fuel, which again can be either the first fuel or the second fuel. The first fuel can be a gaseous fuel or a liquid fuel, and the second fuel can be a gaseous fuel or a liquid fuel. As used herein, a gaseous fuel is any fuel that is in the gaseous state (phase) at standard temperature and pressure, which is defined herein as a temperature of zero (0) degrees Celsius (°C) and an absolute pressure of one hundred (100) kilopascals (kPa), respectively; and a liquid fuel is any fuel that is in the liquid state (phase) at standard temperature and pressure. Examples of gaseous fuels include ammonia, biogas, butane, dimethyl ether (DME), ethane, hydrogen, liquefied petroleum gas, methane, natural gas, propane, and mixtures of two or more of these fuels. Examples of liquid fuels include butanol, diesel fuel ethanol, kerosene, methanol, and propanol. In some embodiments the first fuel inlet fluidly receives a low(er) cetane number fuel and the second fuel fluidly receives a pilot fuel, a relatively high(er) cetane number fuel, employed to ignite the low(er) cetane number fuel. Exemplary low(er) cetane number fuels includes biogas, butane, ethane, hydrogen, liquefied petroleum gas, methane, natural gas, propane, and mixtures of two or more of these fuels, and examples of pilot fuels include diesel fuel, dimethyl ether (DME), and kerosene. In an exemplary embodiment the first fuel is a gaseous fuel with a low cetane number and the second fuel is a pilot fuel with a high cetane number. The fuel(s) supplied to fuel injector 10 can be at a range of pressures depending upon application and engine operating conditions requirements. In some embodiments, the fuel supplied can be as low as 100 bar and as high as 700 bar, although in other embodiments lower and higher pressures are contemplated.

[0049] Fuel injector 10 also includes injection chamber 200, formed between nozzle body 30 and first valve member 40 downstream of first injection valve 120, and injection chamber 210, formed between first valve member 40 and second valve member 50 downstream of second injection valve 150. Injection chamber 200 can be referred to as a sac, as well as injection chamber 210. When first injection valve 120 is closed, injection chamber 200 is fluidly isolated from fueling chamber 180, and when first injection valve 120 is open, injection chamber 200 is in fluid communication with fueling chamber 180. Similarly, when second injection valve 150 is closed, injection chamber 210 is fluidly isolated from fueling chamber 190, and when second injection valve 150 is open, injection chamber 210 is in fluid communication with fueling chamber 190. In some embodiments such as the illustrated embodiment, when first injection valve 120 is an annular valve, injection chamber 200 is an annular chamber. In the illustrated embodiment, injection chamber 210 includes an annular portion and a distal portion below second valve member 50. Nozzle body 30 includes injection passageway 220 extending from injection chamber 200 to and through outer surface 80 of the nozzle body. In some embodiments there is one injection passageway 220, and in other embodiments there is a plurality of injection passageways 220. In the illustrated embodiment, inlet orifice 230 of injection passageway 220 is located closer to a distal, downstream end of injection chamber 200 than to a proximal, upstream end by first injection valve 120. First valve member 40 includes injection passageway 240 extending from injection chamber 210 to and through outer surface 100 of the first valve member. In some embodiments there is one injection passageway 240, and in other embodiments there is a plurality of injection passageways 240. In the illustrated embodiment, inlet orifice 250 of injection passageway 240 is located closer to a distal, downstream end of injection chamber 210 than a proximal, upstream end by second injection valve 150.

[0050] With reference to FIG. 3, valve seat angle <|) of valve seat 150 is the included angle between two axes (in the same plane) extending along the surface of the valve seat and through respective locations on the valve seat that are 180 degrees apart along a circumference of the valve seat. In some embodiments the valve seat angle (|) is between a range of 60 degrees and 100 degrees. In some embodiments the valve seat angle (|) is between a range of 85 degrees and 95 degrees. Injection passageway angle a is the included angle between longitudinal axis 222 of injection passageway 220 and a horizontal plane perpendicular to the longitudinal axis 60. In some embodiments the injection passageway angle a is between a range of 10 degrees and 30 degrees. In some embodiments the inj ection passageway angle a is between a range of 18 degrees and 24 degrees.

[0051] Referring now to FIGS. 1- 9, and first to FIG. 5, injection chamber 200 is now discussed in more detail. Outer surface 100 of first valve member 40 includes tapered portion 260 and ceiling portion 270 within injection chamber 200. Inner surface 70 of nozzle body 30 includes side portion 280 and floor portion 290 within injection chamber 200. Tapered portion 260 of first valve member 40 tapers radially outwardly in the axial direction, relative to the longitudinal axis 60, from first injection valve 120 to and beyond inlet orifice 230 of injection passageway 220, particularly when first injection valve 120 is in the open position, whereby a cross-sectional flow area in injection chamber 200 is greater by the first injection valve compared to by the injection passageway. In some embodiments such as the illustrated embodiment, tapered portion 260 tapers linearly, whereby the cross-sectional flow area in injection chamber 200 decreases linearly along the tapered portion from first injection valve 120 to inlet orifice 230. In some embodiments, tapered portion 260 is a concave surface, whereby the cross-sectional flow area in injection chamber 200 decreases non-linearly along the tapered portion from first injection valve 120 to inlet orifice 230. Side portion 280 extends in the axial direction relative to longitudinal axis 60 from first injection valve 120 to the injection passageway 220. In some embodiments such as the illustrated embodiment, side portion 280 extends vertically. In some embodiments, side portion 280 tapers radially inwardly in the axial direction, relative to the longitudinal axis 60, from first injection valve 120 to inlet orifice 230 of injection passageway 220. In some embodiments, side portion 280 is a convex surface. Ceiling portion 270 extends between tapered portion 260 and sealing surface 140. Floor portion 290 extends between tapered portion 260 and side portion 280.

[0052] Returning to FIG. 3, a tapered portion angle f> of tapered portion 260 is defined as the included angle between two axes (in the same plane) extending along the surface of the tapered portion and through respective locations on the tapered portion that are 180 degrees apart along a circumference of the tapered portion. In some embodiments the tapered portion angle f> is between a range of 10 degrees and 30 degrees. In some embodiments the tapered portion angle f> is between a range of 17 degrees and 23 degrees. With reference to FIGS. 6 and 9, a ceiling portion angle 0 is the angle between valve seat 130 and ceiling portion 270. In some embodiment the ceiling portion angle 0 is greater than zero. In some embodiments the ceiling portion angle 0 is between 5 degrees and 20 degrees. Typically, the ceiling portion angle 0 is made greater than zero to not interfere with the manufacturing of valve seat 130, which requires precision grinding techniques. In the illustrated embodiment, floor portion 290 forms an obtuse angle with side portion 280, although this is not a requirement and in other embodiments, floor portion 290 can form a right angle or an acute angle with side portion 280.

[0053] In other embodiments, fuel injector 10 can be a monofuel injector with only first valve member 40. That is, second valve member 50 along with other features associated with second inj ection valve 150 (such as inj ection passageway 240 and the actuator for the second inj ection valve) can be removed. In this circumstance, first valve member 40 is not required to be hollow but can remain so to reduce the mass of the first valve member.

[0054] Referring to FIG. 10, there is shown combustion chamber 310 of internal combustion engine 300 in which nozzle portion 20 of fuel injector 10 is disposed in an in-cylinder configuration. Combustion chamber 310 is formed by cylinder wall 330 of cylinder 340 in engine block 350, cylinder head 360, and piston 370 that reciprocates within the cylinder. Cylinder wall 330 forms a bore that can have a diameter suitable for internal combustion engines. In the illustrated exemplary embodiment, piston 370 includes an omega-shaped piston bowl 380, although in other embodiments other piston bowl shapes are contemplated. An air handling system includes intake port 390 and intake valve 400, and exhaust port 410 and exhaust valve 420. In some embodiments at a top dead center (TDC) position of piston 370, there is a small gap between the top of piston 370 and fire deck 480. At the TDC position of piston 370, intake valve 400 and exhaust valve 420 can be aligned with recessed portions (not shown) in piston 370 such that the valves can be in an open position without interference with the piston. Intake valve 400 is actuated by valve actuator 430 and exhaust valve 420 is actuated by valve actuator 440. In some embodiments, valve actuators 430 and 440 are part of a cam system. In some embodiments, valve actuators 430 and 440 can be part of a variable valve actuation (VVA) system 450 that can be operatively connected with and commanded by controller 470 to adjust intake valve timing (IVT) and/or intake valve lift (IVL) of intake valve 400 and exhaust valve timing (EVT) and/or exhaust valve lift (EVL) of exhaust valve 420. The term “and/or” is used herein to mean “one or the other or both.”

[0055] With reference to FIGS. 8 and 10, when controller 470 actuates fuel injector 10 to open first injection valve 120, the fuel in fueling chamber 180 is communicated through the open first injection valve 120 to injection chamber 200 towards tapered portion 260 where it is deflected downwards, towards, and into inlet orifice 230 due to a differential pressure between fueling chamber 180 and combustion chamber 310. The outwardly tapering profile of tapered portion 260 in the direction of fluid communication improves the fuel mass flow from fueling chamber 180 to combustion chamber 310 by reducing the pressure drop between first injection valve 120 and inlet orifice 230 of injection passageway 220 (seen in FIG. 9) and increasing fuel velocity through injection chamber 200 and injection passageway 220. The reduced pressure drop and increased velocity of the fuel improves the penetration and mixing of the fuel within combustion chamber 310, which improves the ignition of the fuel and combustion thereof, resulting in more complete combustion thereby reducing emissions and improving fuel economy. Additionally, the outwardly tapering profile of tapered portion 260 reduces the volume of injection chamber 200, which contributes to the reduced pressure drop across and increased fuel velocity through the injection chamber, and in addition the reduced volume of the injection chamber also reduces unbumed fuel emissions. For example, after the fuel within combustion chamber 310 has burned during an engine cycle, there is typically fuel remaining within injection chamber 200. That is, the pressure and temperature environment created within combustion chamber 310, or the flame of combustion, does not cause the fuel within injection chamber 200 to ignite, at least for the likely reason the fuel in the injection chamber is too rich to bum. The fuel within injection chamber 200 begins to trickle (fluidly communicate) into combustion chamber 310 as the pressure in the combustion chamber decreases during the exhaust stroke and this fuel is communicated along with other exhaust gases through exhaust port 410 leading to unbumed fuel emissions. Since the volume of injection chamber 200 is reduced due to the tapered profile of tapered portion 260, the unbum fuel emissions are reduced, improving fuel economy. When the fuel is a hydrocarbon fuel, such as methane or natural gas, the unbumed fuel emissions are referred to as unbumed hydrocarbon emissions (UHC). [0056] Referring now to FIGS. 11, 11b, 12, and 13 there is shown fuel injector 11 according to another embodiment where like parts in this and all other embodiments have like reference numerals and differences are discussed. First valve member 41 includes a channel 500 downstream from first injection valve 120 for each injection passageway 220. Channel 500 is also referred to as a fluted channel herein. In an exemplary embodiment, each fluted channel 500 aligns angularly with inlet orifice 230 of the respective injection passageway 220 with respect to the longitudinal axis 60 of the fuel injector. In some embodiments, like the illustrated embodiment, fluted channel 500 is formed as a recess in first valve member 41. In some embodiments, fluted channel 500 is formed between two protrusions emanating from first valve member 41. Fluted channel 500 helps guide the fuel from first injection valve 120, when open (as seen on left hand side in FIG. 11 and in FIG. 13), towards the respective injection passageway 220. In the illustrated embodiment, valve seat 130 (as seen in FIGS. 13 and 14) is disposed more radially outwardly than fluted channel 500 with respect to longitudinal axis 60 of the fuel injector. Injection chamber 201, downstream from first injection valve 120, is formed between outer surface 101 of first valve member 41 in fluted channel 500 and inner surface 70 of nozzle body 30. With reference to FIGS. 11 to 14, fluted channel 500 is defined by sidewalls 510 and 520 extending on opposite sides of the fluted channel and back wall 540 between the sidewalls 510 and 520. In some embodiments like the illustrated embodiment, sidewalls 510 and 520 stope towards each other in the downstream direction around a circumference of first valve member 41 such that fluted channel 500 is tapered in the downstream direction. In some embodiments, sidewalls 510 and 520 can be substantially vertical. In the illustrated embodiment, adjacent sidewalls 510, 520 from adjacent fluted channels 500 meet at peak 530. In some embodiments, with fewer injection passageways 220 for example, adjacent fluted channels 500 can be spaced further angularly apart from each other with respect to the longitudinal axis 60 of the fuel injector, such that adjacent sidewalls 510, 520 form adjacent fluted channels 500 each ending at respective peaks 530, and a ledge (not shown) extends between the respective peaks 530. With reference to FIG. 14, back wall 540 includes lower section 550 and upper section 560. Lower section 550 is substantially vertical, although in other embodiments it can slope either radially outwardly or radially inwardly. Upper section 560 stopes radially inwardly in the downstream direction with respect to longitudinal axis 60 of fuel injector 11. In some embodiments, tower section 550 and upper section 560 can be like tapered portion 260 and ceiling portion 270, respectively as seen in FIGS. 5 and 6. The relative vertical extent of lower section 550 and upper section 560 can vary depending on application requirements. With reference to FIGS. 11 and 13, a match fit 600 is formed between first valve member 41 and nozzle body 30 around channel 500 and downstream from first injection valve 120 to reduce mass flow of fuel out the end of nozzle portion 20 when the injection valve is open.

[0057] Referring again to FIG. 11, in the illustrated embodiment, fluted channel 500 ends at closed end 570 where sidewalls 510 and 520 converge. In some embodiments, closed end 570 is sloped radially outwardly in the downstream direction. With reference to FIG. 12, when first injection valve 120 is in the closed position, at least a portion of closed end 570 adjacent nozzle body 30 is below inlet orifice 230 of injection passageway 220. In operation, when first injection valve 120 is opened from a closed position, first valve member 41 moves upwardly with respect to nozzle body 30, such that closed end 570 of fluted channel 500 moves upwardly relative to injection passageway 220, as seen in FIG. 13. In the illustrated embodiment, the portion of closed end 570 adjacent nozzle body 30 is near to and slightly below a bottom 235 of the inlet orifice when first injection valve 120 is open. In some embodiments, the portion of closed end 570 adjacent nozzle body 30 is aligned with the bottom 235 of inlet orifice 230 when first injection valve 120 is open. In some embodiments, the portion of closed end 570 adjacent nozzle body 30 is near to and slightly above the bottom 235 of inlet orifice 230 when first injection valve 120 is open. Preferably, a contour 580 of closed end 570 (seen in FIG. 11) matches a contour of the bottom 235 of injection passageway inlet orifice 230 as shown in FIG. 14 and negative partial perspective views shown in FIGS. 17a and 17b. With reference to FIGS. 11 and 14, a mass flow of fuel flows through first injection valve 120 between valve seat 130 and sealing surface 140 around their respective circumferences when the injection valve is open. The entire valve seat flow area is available for flow so as not to reduce the volumetric efficiency of first injection valve 120. Annular space 205 extends around first valve member 41 (best seen in FIG. 13) and is downstream from first injection valve 120 and upstream from channel 500 and is part of the transition from first injection valve 120 to channel 500. A size of annular space 205 can be tuned for optimal flow transition from first injection valve 120 to channel 500, and in some embodiments, annular space 205 is made preferably as small as mechanically possible with respect to the design of the fuel injector to reduce residual fuel downstream from first injection valve 120 after it closes. After the mass flow is past first injection valve 120 it enters annular space 205 and continues towards injection passageways 220 until it reaches channel inlet 590 of respective fluted channels 500 (best seen in FIGS. 11 and 11b) where the mass flow is divided into separate mass flows for each injection passageway 220 as the fuel enters respective fluted channels 500. In some embodiments, the fuel enters the fluted channel 500 through channel inlet 590 substantially flowing in a vertical direction (for example flowing within 30 degrees of the parallel to the longitudinal axis 60). Channel 500 then guides the fuel towards inlet orifice 230 of injection passageway 220. In the illustrated embodiment, a cross-sectional flow area of fluted channel 500 decreases from channel inlet 590 to closed end 570. The cross-sectional flow area of fluted channel 500 can decrease linearly or non-linearly. A negative partial perspective rendering of injection chamber 201 shown in FIGS. 17a and 17b show a linear decreasing cross-sectional flow area of fluted channel 500 from channel inlet 590 to closed end 570. The cross-sectional flow area of fluted channel 500 upstream of inlet orifice 230 is equal to or greater than a cross-sectional flow area of inlet orifice 230. In some embodiments, the cross-sectional flow area of fluted channel 500 is constant from channel inlet 590 to closed end 570.

[0058] Referring now to FIG. 15a, injection passageways 220a are cylindrical in shape with a constant cross-sectional flow area from inlet orifice 230 to outlet orifice 231. Inlet orifice 230 and outlet orifice 231 can have rounded edges to improve fluid flow. With reference to FIG. 15b, in some embodiments, injection passageway 220 is outwardly tapering injection passageway 220b such that a cross-sectional flow area decreases, either linearly or non-linearly, from inlet orifice 230 to outlet orifice 231. The tapered profile can improve efficiency of flow through the injection passageway 220, by increasing exit velocity for a given input condition and mass flow compared to the straight (non-tapered) injection passageway. The fluid accelerates as it flows down the tapered injection passageway reaching maximum velocity near outlet orifice 231. With reference to FIG. 15c, in some embodiments, injection passageway 220 can have a de laval nozzle shape passageway 220c, which is a type of hourglass shape, where a cross-sectional flow area of the injection passageway converges from inlet orifice 230 to a point between the inlet and outlet orifices, and then diverges towards outlet orifice 231 on the combustion chamber side such that the cross-sectional flow area is at its least at the point between the inlet and outlet orifices. A higher fuel stream velocity can be generated on the convergent region of the injection passageway while the divergent region can, for example, mitigate additional narrowing of the injection passageway that can occur due to carbon deposit formation from carbon containing fuels. With reference to FIG. 15d, in some embodiments, injection passageway 220 can have an inwardly tapering passageway 220d which can for example, mitigate narrowing of the injection passageway that can occur due to carbon deposit formation from carbon containing fuels. [0059] Returning to FIGS. 11 and 13, a pressure drop from first injection valve 120 to the combustion chamber is reduced when employing fluted channels 500, which increases mass flow rate for a given pressure drop compared to when a single injection chamber is employed for all injection passageways 220. An exit velocity of the fuel as it leaves injection passageway 220 into the combustion chamber is increased, which improves mixing of the fuel and air within the combustion chamber. A total volume within the fuel injector downstream from the first injection valve 120 is reduced by replacing a single annular common injection chamber (also referred to as a full sac herein) for all injection passageways (FIGS. 1-4 and FIGS. 16a and 16b) with that of individual injection chambers formed from fluted channels 500 (also referred to as fluted sac herein) for each injection passageway (FIGS. 8, 14, 17a and 17b) ). This reduces unbumed fuel emissions since there is less residual fuel within the fuel injector downstream from the injection valve after combustion. Low velocity recirculation zones are reduced when employing fluted channels 500 to guide the flow of the fuel from the injection valve to the inlet orifice of the injection passageways. With reference to FIG. 13, a length of match fit 600 is increased with fluted channels 500 compared to when a single, common, annular injection chamber is employed for injection passageway 220. The increased length of match fit 600 reduces the amount of fuel (particularly when employing gaseous fuel) leaking out the end of nozzle portion 20.

[0060] Referring to FIG. 18, an injection chamber volume bar chart is shown for four fuel injectors having varied exemplary injection chamber geometries. The larger volume of single, common, annular injection chamber 200 of fuel injector 10 (FIG. 1) is shown by the first and second bars (sac design Cl and C2) on the left of the chart. The first bar (sac design Cl) represents the volume of the injection chamber 200 of fuel injector 10 having straight injection passageway(s) 220a (FIG. 15a). The second bar (sac design C2) represents the volume of the injection chamber of fuel injector 10 having outwardly tapering passageway (s) 220b (FIG. 15b). The third bar (sac design C3) represents the volume of the injection chamber (sac with fluted channels 500) of fuel injector 11 having straight injection passageway(s) 220a (FIG. 15a). The fourth bar (sac design C4) represents the volume of the injection chamber (sac with fluted channels 500) of fuel injector 11 with outwardly tapering injection passageway (s) 220b (FIG. 15b). As shown in FIG. 18, the two fuel injectors having injection chambers which include fluted channel geometries (sac designs C3 and C4) have reduced volumes as compared to those of the two fuel injectors having a single common, annular injection chamber (sac design Cl and C2). The fuel injector injection chamber (sac) volume shown in the fourth bar (sac design C4) in FIG. 18 includes outwardly tapering passageways (holes) which increases the volume somewhat as compared to fuel injector injection chamber (sac) volume shown by third bar (sac design C3) in FIG. 18 which has straight injection passageways (220a).

[0061] The graph shown in FIG. 19 summarizes the results by comparing a percent change of mass flow, velocity, and injection chamber (sac) volume of injection chamber design from left to right of C3, C2, C4 compared to a baseline injection chamber design (Cl) having single, common, annular injection chamber 200 with straight injection passageway(s) 220a. The fuel injector with the combination of injection chamber having fluted channels and outwardly tapering injection passageways (Tapered Holes+ Fluted Sac in FIG. 19) showed the greatest increase in both mass flow and velocity at the outlet of injection passageway.

[0062] Similar to fuel injector 10, fuel injector 11 can be a dual fuel injector having first and second valve members (41, 51) or fuel injector 11 can be a monofuel injector with only first valve member 41. That is, the second valve member along with other features associated with a second injection valve, such as an additional fuel injection passageway and the actuator for the second injection valve, can be employed for a second fuel injection or absent in, for example, monofuel arrangements. First valve member 41 can be hollow but is not required for monofuel injector arrangements.

[0063] Examples of Various Embodiments are Described in the Following Paragraphs:

Example Al. A fuel injector comprising a nozzle body comprising an injection passageway extending from an inner surface to an outer surface of the nozzle body and a valve seat on the inner surface thereof; a valve member movable along a longitudinal axis of the fuel injector; an injection valve 120 comprising the valve seat 130 and the valve member, the injection valve is closed when the valve member abuts the valve seat, the injection valve is open when the valve member is spaced apart from the valve seat; the valve member comprising a channel recessed in an outer surface of the valve member; wherein an injection chamber downstream from the injection valve is formed between the outer surface of the valve member in the channel and the inner surface of the nozzle body, the channel moves upwardly relative to the injection passageway when the injection valve is opened whereby the channel guides fuel from the injection valve when open towards the injection passageway. Example A2. In the fuel injector of example Al, wherein the injection passageway comprises an inlet orifice, the channel extends longitudinally and aligns angularly with the inlet orifice with respect to the longitudinal axis of the fuel injector.

Example A3. The fuel injector of example Al or A2, wherein the channel has a fluted shape tapering in a downstream direction.

Example A2. The fuel injector of example Al, A2 or A3, wherein the channel comprises a first sidewall and a second sidewall extending on opposite sides of the channel and a backwall between the first and second sidewalls.

Example A5. The fuel injector of example Al, A2, A3 or A4, wherein the first sidewall and second sidewall slope towards each other in a downstream direction.

Example A6. The fuel injector of example A4 or A5, wherein the backwall slopes radially outwardly relative to a longitudinal axis 60 of the fuel injector in a downstream direction.

Example A7. The fuel injector of example A3, A4, A5 or A6, wherein the channel comprises a closed end 570 downstream from the injection valve moveable when the injection valve opens.

Example A8. The fuel injector of example A7, wherein a contour of the closed end 570 of the channel matches a bottom contour of an inlet orifice of the injection passageway.

Example A9. The fuel injector of example A4, wherein a portion of the closed end 570 of the channel adjacent the nozzle body 30 is positionally disposed below a bottom 235 of an inlet orifice 230 of the injection passageway 220 when the injection valve is closed.

Example A10. The fuel injector of example A9, wherein the closed end 570 of the channel moves longitudinally upwards relative to the injection passageway inlet orifice 230 when the injection valve opens.

Example All. The fuel injector of example A10, wherein a portion of the closed end 570 of the channel adjacent the nozzle body 30 is near to or aligns with the bottom of the injection passageway inlet orifice 230 when the injection valve is open. Example Al 2. The fuel injector of any one of examples Al -All, wherein a channel inlet 590 of the channel 500 is positionally disposed below the valve seat 130 when the injection valve is open.

Example A13. The fuel injector of example A12, further comprising an annular space 205 around the valve member 41 downstream from the injection valve 120 and upstream of the channel 500.

Example A14. The fuel injector of example A12 or A13, wherein a mass flow of fuel from the injection valve when open enters the channel inlet 590 flowing within 30 degrees of a parallel to the longitudinal axis of the fuel injector.

Example A15. The fuel injector of any one of examples Al 1-A14, wherein the valve seat is disposed more radially outwardly than the channel with respect to the longitudinal axis of the fuel injector.

Example Al 6. The fuel injector of any one of examples Al -Al 5, wherein fuel enters the channel substantially from above.

Example Al 7. The fuel injector of any one of examples Al -Al 6, further comprising a match fit between the valve member and the nozzle body around the channel and downstream from the injection valve.

Example A18. The fuel injector of any one of examples A1-A17, wherein the injection passageway 220 is tapered outwardly relative to a longitudinal axis 60 of the fuel injector in a downstream direction.

Example Al 9. The fuel injector of any one of examples Al -Al 7, wherein the injection passageway 220 comprises an inlet orifice 230 and an outlet orifice 231, wherein a cross-sectional flow area of the inj ection passageway 220 converges from the inlet orifice towards a point between the inlet orifice and outlet orifice, and then diverges thereafter towards the outlet orifice.

Example 20. An injection chamber for a fuel injector, the fuel injector comprising a nozzle body including an injection passageway extending from an inner surface to an outer surface of the nozzle body and a valve seat on the inner surface thereof, a valve member movable along a longitudinal axis of the fuel injector, an injection valve including the valve seat and the valve member, the injection valve is closed when the valve member abuts the valve seat, the injection valve is open when the valve member is spaced apart from the valve seat, the injection chamber comprising: a channel recessed in an outer surface of the valve member; wherein the injection chamber is formed between the channel and the nozzle body, the channel operative to move upwardly relative to an inlet orifice 230 of the injection passageway when the injection valve is opened whereby the channel guides fuel from the injection valve in an open position towards the injection passageway inlet orifice.

[0064] It should be noted that the terms "first" and "second" and the like herein are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. The terms so used may be interchanged under appropriate circumstances such that embodiments described herein may be used. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover anon-exclusive inclusion.

[0065] In this application, the terms "upper", "lower", "top", "bottom", "inner", "outer", "horizontal", "longitudinal", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings and in some, but not all, operational applications as would be understood by those skilled in the art. These terms are not intended to otherwise limit the indicated devices, elements, or components to a particular orientation.

[0066] While particular elements, embodiments and applications of the present invention have been shown and described, it will be understood, that the invention is not limited thereto since modifications can be made by those skilled in the art without departing from the scope of the present disclosure, particularly in light of the foregoing teachings.

Claims

We claim:

1. A fuel injector comprising: a nozzle body comprising an inner surface, the inner surface comprising a valve seat; a first valve member configured to reciprocate along a longitudinal axis of the fuel injector within the nozzle body, the first valve member comprising an outer surface, the outer surface comprising a sealing surface engageable with the valve seat of the nozzle body, the sealing surface of the first valve member and the valve seat of the nozzle body forming a first injection valve, the first valve member movable between a closed position where the sealing surface abuts the valve seat whereby the first injection valve is closed and an open position where the sealing surface is spaced apart from the valve seat whereby the first injection valve is open; an injection chamber downstream from the first injection valve, the injection chamber defined by the outer surface of the first valve member and the inner surface of the nozzle body; the nozzle body further comprising an injection passageway extending from the injection chamber through the nozzle body to an outer surface of the nozzle body; wherein a tapered portion of the outer surface of the first valve member within the injection chamber tapers radially outwardly in an axial direction relative to the longitudinal axis from the first injection valve to the injection passageway whereby a cross-sectional flow area in the injection chamber is greater by the first injection valve compared to by the injection passageway.

2. The fuel injector as claimed in claim 1, wherein the tapered portion of the outer surface in the injection chamber tapers linearly.

3. The fuel injector as claimed in claim 1, wherein the tapered portion of the outer surface in the injection chamber is a concave surface.

4. The fuel injector as claimed in claim 1, wherein the cross-sectional flow area in the injection chamber decreases from the first injection valve towards the injection passageway.

5. The fuel injector as claimed in claim 1, wherein a side portion of the inner surface of the nozzle body in the injection chamber extends vertically from the first injection valve to the injection passageway.

6. The fuel injector as claimed in claim 1, wherein a side portion of the inner surface of the nozzle body within the injection chamber tapers radially inwardly in a longitudinal direction from the first injection valve to the injection passageway.

7. The fuel injector as claimed in claim 1, further comprising a ceiling portion of the outer surface of the first valve member extending between the tapered portion of the outer surface of the first valve member and the sealing surface of the first valve member.

8. The fuel injector as claimed in claim 7, wherein an angle between the ceiling portion and the sealing surface of the first valve member is between a range of 5 degrees and 20 degrees.

9. The fuel injector as claimed in claim 1, wherein a valve seat angle is in a range of 60 degrees and 100 degrees.

10. The fuel injector as claimed in claim 1, wherein a tapered portion angle is in a range of 10 degrees and 30 degrees.

11. The fuel injector as claimed in claim 1, wherein an injection passageway angle is in a range of 10 degrees and 30 degrees.

12. The fuel injector as claimed in claim 1, wherein a valve seat angle is in a range of 85 degrees and 95 degrees; a tapered portion angle is in a range of 17 degrees and 23 degrees; and an injection passageway angle is in a range of 18 degrees and 24 degrees.

13. The fuel injector as claimed in claim 1, wherein the valve seat in the nozzle body and the sealing surface on the first valve member are annular.

14. The fuel injector as claimed in claim 1, wherein the injection chamber is annular.

15. The fuel injector as claimed in claim 1, wherein the fuel injector is a dual-fuel injector that injects a first fuel through the first injection valve and the first valve member is hollow including an inner surface having a valve seat, the dual -fuel injector further comprising a second valve member disposed within the first valve member and configured to reciprocate longitudinally therein, the second valve member comprising a sealing surface; the sealing surface of the second valve member and the valve seat of the first valve member forming a second injection valve, the second valve member movable between a closed position where the sealing surface of the second valve member abuts the valve seat of the first valve member whereby the second injection valve is closed and an open position where the sealing surface of the second valve member is spaced apart from the valve seat of the first valve member whereby the second injection valve is open; a second injection chamber downstream from the second injection valve, the second injection chamber defined by the outer surface of the second valve member and the inner surface of the first valve member; the first valve member further comprising an inj ection passageway extending from the second injection chamber through the first valve member to the outer surface of the first valve member.

16. The fuel injector as claimed in claim 1, wherein the fuel injector injects a gaseous fuel.

17. The fuel injector as claimed in claim 16, wherein the gaseous fuel is selected from the list containing ammonia, biogas, butane, ethane, hydrogen, liquefied petroleum gas, methane, natural gas, propane, and mixture of two or more of these gaseous fuels.

18. The fuel injector of any one of claims 1-17, wherein the injection passageway is tapered outwardly relative to a longitudinal axis 60 of the fuel injector in a downstream direction.

19. The fuel injector of any one of claims 1-17, wherein the injection passageway comprises an inlet orifice and an outlet orifice, wherein a cross-sectional flow area of the injection passageway converges from the inlet orifice towards a point between the inlet orifice and outlet orifice, and then diverges thereafter towards the outlet orifice.

20. The fuel injector of any one of claims 1-17, wherein the injection passageway is tapered inwardly relative to a longitudinal axis 60 of the fuel injector in a downstream direction.

21. An internal combustion engine comprising a combustion chamber; and a fuel injector as claimed in claim 1 configured to directly inject a fuel into the combustion chamber.

22. The internal combustion engine as claimed in claim 21, wherein the fuel injector is actuated to inject the fuel after 120 crank angle degrees during a compression stroke.

23. The internal combustion engine as claimed in claim 21, wherein the fuel is a gaseous fuel.

24. The internal combustion engine as claimed in claim 21, wherein the fuel injector is a dual-fuel injector as claimed in claim 15, the dual-fuel injector injects a first fuel into the combustion chamber through the first injection valve and the injection passageway in the nozzle body, and the dual-fuel injector injects a second fuel into the combustion chamber through a second injection valve and the injection passageway in the first valve member.

25. The internal combustion engine as claimed in claim 24, wherein the first fuel is a gaseous fuel and the second fuel is a liquid fuel.

26. The internal combustion engine as claimed in claim 24, wherein the first fuel is selected from the list containing ammonia, biogas, butane, ethane, hydrogen, liquefied petroleum gas, methane, natural gas, propane, and mixture of two or more of these gaseous fuels; and the second fuel is selected from the list containing diesel fuel, dimethyl ether (DME), kerosene, and mixtures of two or more of these fuels.

27. The internal combustion engine as claimed in claim 24, wherein the first fuel comprises methanol, ethanol, propanol, butanol, or dimethyl ether (DME).

28. A method for injecting fuel with a fuel injector comprising: providing a nozzle body comprising an inner surface, the inner surface comprising a valve seat; providing a first valve member configured to reciprocate along a longitudinal axis of the fuel injector within the nozzle body, the first valve member comprising an outer surface, the outer surface comprising a sealing surface engageable with the valve seat of the nozzle body; forming a first injection valve with the sealing surface of the first valve member and the valve seat of the nozzle body, the first valve member movable between a closed position where the sealing surface abuts the valve seat whereby the first injection valve is closed and an open position where the sealing surface is spaced apart from the valve seat whereby the first injection valve is open; providing an injection chamber downstream from the first injection valve, the injection chamber defined by the outer surface of the first valve member and the inner surface of the nozzle body; providing in the nozzle body an injection passageway extending from the injection chamber through the nozzle body to an outer surface of the nozzle body; and tapering a tapered portion of the outer surface of the first valve member within the injection chamber radially outwardly in an axial direction relative to the longitudinal axis from the first injection valve to the injection passageway whereby a cross-sectional flow area in the injection chamber is greater by the first injection valve compared to by the injection passageway.

29. The method as claimed in claim 28, wherein the fuel injector is a dual-fuel injector that injects a first fuel through the first injection valve and the first valve member is hollow including an inner surface having a valve seat, the method further comprising providing a second valve member disposed within the first valve member and configured to reciprocate longitudinally therein, the second valve member comprising a sealing surface; forming a second injection valve with the sealing surface of the second valve member and the valve seat of the first valve member, the second valve member movable between a closed position where the sealing surface of the second valve member abuts the valve seat of the first valve member whereby the second injection valve is closed and an open position where the sealing surface of the second valve member is spaced apart from the valve seat of the first valve member whereby the second injection valve is open; providing a second injection chamber downstream from the second injection valve, the second injection chamber defined by the outer surface of the second valve member and the inner surface of the first valve member; providing in the first valve member further an injection passageway extending from the second injection chamber through the first valve member to the outer surface of the first valve member.