CA2406883C - Directly actuated gaseous fuel injection valve with a movable nozzle - Google Patents
Directly actuated gaseous fuel injection valve with a movable nozzle Download PDFInfo
- Publication number
- CA2406883C CA2406883C CA002406883A CA2406883A CA2406883C CA 2406883 C CA2406883 C CA 2406883C CA 002406883 A CA002406883 A CA 002406883A CA 2406883 A CA2406883 A CA 2406883A CA 2406883 C CA2406883 C CA 2406883C
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- Prior art keywords
- nozzle
- fuel
- injection valve
- sealing surface
- fuel injection
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Links
- 239000000446 fuel Substances 0.000 title claims abstract description 201
- 238000002347 injection Methods 0.000 title claims abstract description 135
- 239000007924 injection Substances 0.000 title claims abstract description 135
- 238000007789 sealing Methods 0.000 claims abstract description 47
- 238000002485 combustion reaction Methods 0.000 claims abstract description 45
- 238000000034 method Methods 0.000 claims abstract description 30
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 22
- 239000012530 fluid Substances 0.000 claims description 14
- 239000000463 material Substances 0.000 claims description 11
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 claims description 10
- 239000001257 hydrogen Substances 0.000 claims description 7
- 229910052739 hydrogen Inorganic materials 0.000 claims description 7
- 239000007788 liquid Substances 0.000 claims description 7
- 239000007787 solid Substances 0.000 claims description 7
- 239000003345 natural gas Substances 0.000 claims description 6
- 238000007493 shaping process Methods 0.000 claims description 6
- OTMSDBZUPAUEDD-UHFFFAOYSA-N Ethane Chemical compound CC OTMSDBZUPAUEDD-UHFFFAOYSA-N 0.000 claims description 5
- 239000001294 propane Substances 0.000 claims description 5
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 4
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 4
- 229910052692 Dysprosium Inorganic materials 0.000 claims description 2
- 229910052771 Terbium Inorganic materials 0.000 claims description 2
- KBQHZAAAGSGFKK-UHFFFAOYSA-N dysprosium atom Chemical compound [Dy] KBQHZAAAGSGFKK-UHFFFAOYSA-N 0.000 claims description 2
- 229910052742 iron Inorganic materials 0.000 claims description 2
- 229910001092 metal group alloy Inorganic materials 0.000 claims description 2
- GZCRRIHWUXGPOV-UHFFFAOYSA-N terbium atom Chemical compound [Tb] GZCRRIHWUXGPOV-UHFFFAOYSA-N 0.000 claims description 2
- 238000007906 compression Methods 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 6
- 230000006835 compression Effects 0.000 description 5
- 239000002283 diesel fuel Substances 0.000 description 4
- 230000004907 flux Effects 0.000 description 4
- 150000002431 hydrogen Chemical class 0.000 description 3
- 241001517546 Etrema Species 0.000 description 2
- 229910001329 Terfenol-D Inorganic materials 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 238000006073 displacement reaction Methods 0.000 description 2
- 239000013618 particulate matter Substances 0.000 description 2
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- 230000003213 activating effect Effects 0.000 description 1
- 230000003321 amplification Effects 0.000 description 1
- 238000000889 atomisation Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
- 230000036316 preload Effects 0.000 description 1
- GABUSZPTCJGKGB-UHFFFAOYSA-M sodium;4-(4-chloro-2-methylphenoxy)butanoate Chemical compound [Na+].CC1=CC(Cl)=CC=C1OCCCC([O-])=O GABUSZPTCJGKGB-UHFFFAOYSA-M 0.000 description 1
- 238000013517 stratification Methods 0.000 description 1
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M21/00—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form
- F02M21/02—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form for gaseous fuels
- F02M21/0218—Details on the gaseous fuel supply system, e.g. tanks, valves, pipes, pumps, rails, injectors or mixers
- F02M21/0248—Injectors
- F02M21/0257—Details of the valve closing elements, e.g. valve seats, stems or arrangement of flow passages
- F02M21/026—Lift valves, i.e. stem operated valves
- F02M21/0263—Inwardly opening single or multi nozzle valves, e.g. needle valves
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M21/00—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form
- F02M21/02—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form for gaseous fuels
- F02M21/0218—Details on the gaseous fuel supply system, e.g. tanks, valves, pipes, pumps, rails, injectors or mixers
- F02M21/0248—Injectors
- F02M21/0251—Details of actuators therefor
- F02M21/0254—Electric actuators, e.g. solenoid or piezoelectric
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M51/00—Fuel-injection apparatus characterised by being operated electrically
- F02M51/06—Injectors peculiar thereto with means directly operating the valve needle
- F02M51/0603—Injectors peculiar thereto with means directly operating the valve needle using piezoelectric or magnetostrictive operating means
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M61/00—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00
- F02M61/04—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00 having valves, e.g. having a plurality of valves in series
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M61/00—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00
- F02M61/04—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00 having valves, e.g. having a plurality of valves in series
- F02M61/08—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00 having valves, e.g. having a plurality of valves in series the valves opening in direction of fuel flow
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/30—Use of alternative fuels, e.g. biofuels
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Analytical Chemistry (AREA)
- Fuel-Injection Apparatus (AREA)
Abstract
A directly actuated fuel injection valve is provided for injecting a gaseous fuel into a combustion chamber. The fuel injection valve comprises a valve body with a fuel cavity supplied with fuel from a fuel inlet passage. A nozzle associated with one end of the valve body comprises at least one nozzle orifice through which the gaseous fuel is injectable into the combustion chamber. In relation to the valve body, the nozzle is movable between a closed position, wherein the nozzle is seated against a sealing surface to provide a boundary between the fuel cavity and the one nozzle orifice(s), and an open position, wherein the nozzle is spaced apart from the sealing surface. A spring biases the nozzle in the closed position, and an actuator is operable to move the nozzle to the open position against the bias of the spring. A method is also provided for operating the disclosed injection valve to inject gaseous fuel into a combustion chamber by moving a nozzle relative to the valve body.
Description
..
DIRECTLY ACTUATED GASEOUS FUEL INJECTION
VALVE WITIi A MOVABLE NOZZLE
Technical Field The present invention relates generally to high pressure fuel 5 injection valves or injectors for internal combustion engines, and, more specifically, to a fuel injection valve with a stationary needle and a movable nozzle that is directly controllable by a position activating material (such as, for example, a piezoelectric or magnetostrictive material). The invention also relates to a method of 10 operating a directly actuated fuel injection vaPve with a movable nozzle. 'fhe apparatus and method are particularly suitable for injecting gaseous fuels directly into the combustion chamber of an internal combustion engine.
15 Background Direct injection of a gaseous fuel into the combustion chamber of an internal combustion engine is desirable for several reasons. For example, direct injection allows charge stratification, eliminating throttling losses associated with homogeneous charge engines.
DIRECTLY ACTUATED GASEOUS FUEL INJECTION
VALVE WITIi A MOVABLE NOZZLE
Technical Field The present invention relates generally to high pressure fuel 5 injection valves or injectors for internal combustion engines, and, more specifically, to a fuel injection valve with a stationary needle and a movable nozzle that is directly controllable by a position activating material (such as, for example, a piezoelectric or magnetostrictive material). The invention also relates to a method of 10 operating a directly actuated fuel injection vaPve with a movable nozzle. 'fhe apparatus and method are particularly suitable for injecting gaseous fuels directly into the combustion chamber of an internal combustion engine.
15 Background Direct injection of a gaseous fuel into the combustion chamber of an internal combustion engine is desirable for several reasons. For example, direct injection allows charge stratification, eliminating throttling losses associated with homogeneous charge engines.
2 0 Additionally, with direct injection late in the compression stroke, a high-compression ratio can be maintained far higher efficiency.
Further, when the directly injected fuel comprises methane, natural gas, propane, ethane, other gaseous combustible hydrocarbon derivatives, or hydrogen, compared to liquid fuels such as diesel fuel, 2 5 the emissions of NOX a.nd particulate matter (PM) are significantly reduced. The directly injected gaseous fuel can be ignited with a glow plug, with a spark plug or with a small amount of pilot diesel fuel. The gaseous fuel needs to be injected at high pressure to overcome the combustion chamber pressure, which is high at the end 3 0 of the compression stroke (near top dead center). Preferably, the injection pressure is high enough to promote good mixing between the injected fuel and the combustion chamber air. For example, the gaseous fuel injection pressure is preferably at least about 3000 psi (21 MPa); however, this is much less than the pressures typical of 5 diesel-fueled engines, which typically inject liquid diesel fuel into the combustion chamber at pressures of at least about 22,000 psi (150 MPa). Higher pressures are preferred by conventional diesel engines for atomization of the liquid fuel.
Conventional fuel injection valves typically employ a movable 10 needle disposed within an injection valve body. Injection valves normally have a nozzle or injector tip that is held in a fixed position with respect to the injection valve body. Co-owned U.S. Patent No.
6,298,829 (the '829 Patent) discloses an injection valve with such an arrangement. The injection valve described in the '829 Patent is 15 suitable for injecting gaseous fuels directly into the combustion chamber of an internal combustion engine. T"he '829 Patent discloses a valve needle that is lifted away from a seat surface provided in the nozzle of the injection valve. With this arrangement, the fuel is introduced into the injection valve at an end that is opposite to the 2 0 nozzle, and the fuel flows through the valve body, which also houses a piezoelectric or magnetostrictive actuator. While this arrangement may be suitable for fuels such as natural gas, with other gaseous fuels such as hydrogen, it may not be desirable to have the fuel flowing through the whole injection valve body, because such fuels may be 2 5 incompatible with some of the materials of the inner valve components, including the actuator.
Accordingly, it would be an advantage for a fuel injection valve to isolate the fuel from certain valve components, including the actuator assembly.
U.S. Patent No. 5,031,841 (the '841 patent) describes a metering valve using an actuating member, which according to the patent could be a piezoelectric stack or a magnetostrictive actuator.
One feature disclosed by the '841 patent is the addition of a 5 diaphragm which has the dual purpose of acting as a spring, biasing the valve in its closed position, and, of providing a seal between the metered fluid and the actuator. The ' 841 patent discloses an adjusting screw for mechanically setting the position o1' the actuator within the housing. According to the ' 841 patent, the movable valve needle is 1 o rigidly connected to the actuator by a pressure pin. A problem of this design includes the size and shape of the injection valve body necessary to accommodate the diaphragm, as well as the durability requirements of the diaphragm to resist failure.
15 Summary A directly actuated fuel injection valve is provided for injecting a gaseous fuel into a combustion chamber. The injection valve comprises:
(a) a valve body comprising:
2 o a fuel inlet passage; and a fuel cavity fluidly connected to the fuel inlet passage;
(b) a nozzle comprising at least one nozzle orifice through which the gaseous fuel is injectable into the combustion chamber, wherein the nozzle is associated with an end of the valve body and 2 5 movable in relation thereto between:
a closed position, wherein the nozzle is seated against a sealing surface to provide a boundary between the fuel cavity and the at least one nozzle orifice;
an open position, wherein the nozzle is spaced apart 3 o from the sealing surface;
(c) a spring for biasing the nozzle in the closed position;
and (d) an actuator for moving the nozzle to the open position against the bias of the spring.
5 The fuel injection valve preferably further comprises a needle member fixedly associated with the valve body and extending into an interior space within the nozzle. In a preferred arrangement, the sealing surface is associated with the needle member.
The fuel cavity is preferably associated with the nozzle so that l0 it is close to the nozzle orifices. A fuel supply passage for supplying fuel from the fuel inlet passage to the fuel cavity may comprise a fluid passage provided within the needle member.
In preferred embodiments, the combustion chamber is one of a plurality of combustion chambers in a multi-cylinder engine, and 15 the fuel injection valve is preferably one of a plurality of fuel injection valves, each associated with a respective combustion chamber.
The actuator preferably comprises a magnetostrictive or piezoelectric member that expands in a direction that is parallel 'to the 2 0 direction of movement of the nozzle. When a magnetostrictive member is employed, it expands in length when it is subjected to a magnetic field. When a piezoelectric member is employed, it expands in length when it is energized by the application of a voltage to the piezoelectric elements. In a preferred embodiment, the valve 2 5 nozzle, actuated by a magnetostrictive or piezoelectric actuator assembly is controllable to move between the closed and open positions in less than about 250 microseconds.
The magnetostrictive or piezoelectric member is preferably in the shape of a solid cylinder, which may be pre-loaded with a 3 0 compressive force. By pre-loading magnetostrictive members and _.
piezoelectric stacks, net displacement can be increased per respective unit of applied magnetic field or applied voltage. Accordingly, a compression spring member may be employed for applying a compressive force to pre-load the magnetostrictive member or 5 piezoelectric stack. In a preferred embodiment, the compression spring member comprises at least one disc spring (also known as a Belleville spring or Belleville washer).
A magnetostrictive material that is suitable for use in the present injection valve comprises a material known as ETREMA
1 o Terfenol-D~ magnetostrictive alloy that is available from Etrema Products Inc. ETkEMA Terfenol-D~ magnetostrictive alloy is a metal alloy composed of the elements terbium, dysprosium, and iron.
The actuator is preferably housed within a chamber within the valve body that is fluidly isolated from the gaseous fuel.
15 A passive hydraulic link assembly is preferably disposed between the actuator and the nozzle, whereby actuating forces for lifting the nozzle away from the sealing surface are transmitted through the passive hydraulic link assembly. The passive hydraulic link assembly preferably comprises a piston disposed within a fluidly 2 o sealed cylinder that is filled with a liquid.
An advantage of the present injection valve is that it provides an injection valve that eliminates the need for an active hydraulic operator and the associated high-pressure hydraulic system for generating the actuation force to actuate the injection valve.
2 5 Conventional active hydraulic operators are different from the passive hydraulic link of the present invention, which is described as a "passive" hydraulic link because the hydraulic; fluid sealed within the passive hydraulic link assembly merely transmits the actuating forces but is not employed to generate an actuating force for actuating the 3 o valve. During an injection event, there is substantially no flow or displacement of the hydraulic fluid, unlike active hydraulic actuators or systems that use hydraulic amplification chambers that displace hydraulic fluid to amplify an actuation stroke. Rather, the purpose of the passive hydraulic link is to provide a load path for the opposing 5 actuating forces that originate from at least one spring member and the actuator assembly, which preferably comprises a magnetostrictive or piezoelectric element.
In some embodiments, actuating forces are transmitted between the passive hydraulic link assembly and the movable nozzle 1 o through at least one rigid anember may be disposed therebetween.
Such a rigid member may extend through an open space provided within the valve body and/or the needle member. A plurality of rigid members may be employed to distribute the actuating forces over a larger cross-sectional area. In some embodiments, a rigid plate may 15 be disposed between the plurality of rigid members and the nozzle member to help distribute the actuation forcew transmitted through the rigid member(s).
In a preferred embodiment, the nozzle comprises a hollow cylindrical body with an annular shoulder provided in the hollow 2 o interior axially between the nozzle orifice and the fuel cavity for cooperating with a sealing surface associated with the needle member.
The nozzle preferably further comprises a flanged end disposed within the valve body. In this embodiment, the spring for 2 5 biasing the nozzle in the closed position is disposed between a lateral surface of the flanged end and the valve body, whereby the flanged end cooperates with the spring for biasing the nozzle in the closed position.
7 _.
In a specific preferred embodiment of a fuel injection valve for injecting a fuel into a combustion chamber of an internal combustion engine, the injection valve comprises:
(a) a valve body comprising:
5 a fuel inlet passage; and a fuel cavity fluidly connected to the fuel inlet passage;
(b) a needle member fixedly associated with the valve body;
(c) a nozzle comprising at least one nozzle orifice through 1 o which the fuel is injectable into the combustion chamber, the nozzle disposed around the needle member and movable in relation to the needle member between:
a closed position, wherein the nozzle is seated against a sealing surface of the needle member, to provide a boundary 15 between the fuel cavity and the at least one nozzle orifice;
an open position, wherein the nozzle is spaced apart from the sealing surface of the needle member;
(d) a spring for biasing the nozzle in the closed position;
(e) an actuator for moving the nozzle to the open position 2 o against the bias of the spring, the actuator comprising an actuating member that is expandable in a direction parallel to the direction of movement of the nozzle; and (f) a passive hydraulic link assembly disposed between the actuator and the nozzle, whereby actuating forces for lifting the 2 5 nozzle away from the valve needle are transmitted from the actuator through the passive hydraulic link assembly.
Like in the other embodiments, the actuating member preferably comprises a magnetostrictive or piezoelectric material. An advantage of using such materials is that the actuator is controllable 3 o during an injection event to cantrol the speed at which the nozzle _ g ..
moves from the closed position to the open position, in addition to the distance the nozzle is lifted from the sealing surface.
In preferred embodiments, the actuator is housed within a chamber of the valve body that is fluidly isolated from the fuel. In 5 this embodiment, the fuel may be a gaseous or liquid fuel that is a cleaner burning fuel, compared to diesel fuel. Examples of such fuels include natural gas, methane, propane, ethane, and hydrogen.
Isolating the actuator from the fuel is particularly advantageous, with fuels such as hydrogen, which may be reactive with some of the:
10 actuator components.
For ease of manufacture and maintenance servicing, in some embodiments the valve body may comprise a plurality of parts, which are joined with each other to provide a fluidly sealed body. For' example, the valve housing may comprise a hollow upper housing, a 15 hollow lower housing, and a removable needle member. When the removable needle member is installed, it is fixedly associated with the valve body, but if it gets worn down, it can be replaced by separating the upper and lower housings and removing the needle member.
A method is provided of injecting a gaseous fuel into a 2 o combustion chamber of an internal combustion engine. The method comprises introducing a gaseous fuel into a fuel cavity within an injection valve body;
containing the gaseous fuel within the fuel cavity by 2 5 seating a movable nozzle against a sealing surface associated with the injection valve body;
commencing an injection event by lifting the movable nozzle away from the sealing surface; and terminating an injection event by re-seating the 3 o movable nozzle against the sealing surface.
_ g _ In a preferred method the gaseous fuel is delivered to the fuel cavity from a common rail fuel supply system. The fuel pressure within the fuel cavity is preferably at least about 1000 psi (about 6.9 MPa), and more preferably greater than about 2000 psi (greater than 5 about 13.8 MPa) when the engine is operating.
The preferred method further comprises lifting the movable nozzle away from the sealing surface for the duration of an injection event, and controlling the speed of nozzle movement between the open and closed positions as well as the distance the nozzle is lifted 1 o from the sealing surface. By controlling nozzle movement in these ways, and the overall duration of the injection event, the mass of the gaseous fuel that is injected into the combustion chamber during an injection event can be controlled, and the timing for injecting the fuel can be controlled in accordance with predetermined "rate shapes" . In 15 a preferred method the rate shape and mass flow rates can be determined based upon a measured engine operating parameter.
These and other advantages are provided by a directly actuated fuel injection valve with a movable nozzle as described below.
Brief Description Of The Drawings Figure 1 is a cross-sectional view of a preferred embodiment of a directly actuated fuel injection valve with a movable nozzle; and Figure 2 is an enlarged cross-sectional view of the nozzle end 2 5 of the fuel injection valve of Figure l .
Detailed Description Of Preferred Embodiment(S) A preferred embodiment of gaseous fuel injection valve 100 with movable nozzle 110 will be described with reference to Figures 3 0 1 and 2. Figures 1 and 2 are both cross-sectional views with Figure 2 being an enlarged detailed view of the nozzle end of fuel injection valve 100.
Fuel injection valve 100 comprises a valve body 102, which comprises fuel inlet passage 104 and fuel cavity 106, which is fluidly 5 connected to fuel inlet passage 104. Fuel cavity 106 comprises an annular space between needle 120 and nozzle 110. Fuel inlet passage 104 may comprise passages provided within valve body 102 and needle 120, and in spaces defined therebetween. For example, in the illustrated embodiment, fuel inlet passage 104 comprises bore 1;Z2 1 o and branches 124 and 126 provided within an upper portion of needle 120, through which gaseous fuel may flow on its way to fuel cavity 106. Preferably the fuel passages are constructed so that gaseous fuel may flow through fuel inlet passage 104 to fuel cavity 106 without contacting actuator assembly 130 or passive hydraulic link assembly 15 140. Seals such as o-ring seals 108 fluidly isolate the pressurized fuel passages from passive hydraulic link assembly 140. Seal 109 prevents gaseous fuel from escaping from fuel cavity 106, through the gap between nuzzle 110 and needle 120. Different types of seals known to those skilled in the art may be employed instead of the; o-2 o ring seals that are shown in Figures 1 and 2 for illustrative purposes.
As shown in the illustrated embodiment, needle 120 is fixedly associated with valve body 102. Preferably needle 120 is a removable component so that it can be replaced if the sealing surface becomes worn. Manufacturing needle 120 as a separate component 2 5 also facilitates the manufacturing of the (uel passages for supplying the gaseous fuel to fuel cavity 106. Unlike conventional gaseous fuel injection valves, once assembled, installed, and operational, needle 120 is stationary with respect to valve body 102.
Nozzle 110 comprises at least one nozzle orifice 112 through 3 o which gaseous fuel is injectable into a combustion chamber.
- ~_ 1 ._ Preferably, the tip of nozzle 11U that extends out of the valve body is the only part of fuel injection valve 100 that is directly exposed to the engine combustion chamber, with most of valve body 102 disposed within the engine cylinder head or above the cylinder head.
5 Nozzle L 10 is movable with respect tc> valve body 102 and needle 120. Fuel injection valve 100 is closed when nozzle 110 is seated against a sealing surface of needle 120, and is opened when nozzle 110 is lifted away from the sealing surface in the direction of the combustion chamber, defined herein as the outward direction. In 1 o the illustrated embodiment, the sealing surface is that portion of needle 120, which contacts nozzle 110 when nozzle 110 is urged towards needle 120. When nozzle 110 moves from an open position to a closed position, this direction of movement is defined herein as inward movement. When nozzle 110 is seated against needle 120 a 15 fluid tight boundary is formed between fuel cavity 106 and nozzle orifices) 112.
Controlling the distance nozzle 110 is lifted away from the sealing surface of needle 120, during an injection event, can influence the rate of injecting gaseous fuel into the combustion chamber.
2 o Generally, the greater the distance that nozzle 110 is lifted away from the sealing surface, the greater the mass flow rate of gaseous fuel into the combustion chamber. An upper limit on mass flow rate is eventually reached when the open area of the nozzle orifices limits the flow.
2 5 The timing far injecting gaseous fuel during an injection event can also be controlled by changing the lift distance and fuel mass flow rate during an injection event. 'This technique is defined herein as "rate shaping" because nozzle lift is controllable to influence the mass flow rate of gaseous fuel injection into tike combustion chamber.
3 o Rate shaping is made possible by employing an actuator assembly 130 comprising magnetostrictive or piezoelectric .elements to directly actuate nuzzle 110. Conventional hydraulically actuated injection valves du not have the same capability for rate shaping as directly actuated injection valves.
5 Spring 114 is disposed between an annular shoulder provided by valve body 102 and flange 116 of nozzle 110. With the illustrated arrangement, spring 114 biases nozzle 110 in the closed position.
Spring 114 is illustrated as a disc spring, which is also known as a Belleville washer or Belleville spring. As thaw skilled in the art 1 o would understand, other types of springs may be substituted to achieve substantially the same result.
The illustrated embodiment of actuator assembly 130 comprises solid magnetostrictive member 132. The cross-sectional area of magnetostrictive member 132 is dictated by the force 15 necessary to overcome all of the opposing forces that hold nozzle 110 in the closed position. A greater crass-sectional area results in larger opening forces. Because the crass-sectic~c~al area of magnetostrictive member 132 is solid, its diameter can be smaller than the diameter of the tubular magnetostrictive member disclosed in the '829 Patent 2 o referred to above. Employing known manufacturing techniques, a solid rod is also much easier to manufacture compared to a tubular member.
Spool 134 holds electric coil 136. Flux tube 138 surrounds electric coil 136 and spool 134. Flux tube 138 can have a lengthwise 25 slit to break eddy currents. To activate the actuator, an electric current is supplied to energize electric Gail 136, causing a magnetic flux to develop that flows through magnetostrictive member 132.
When a magnetic flux flows through magnetastrictive member 132 an actuating farce is generated by magnetastrict~ve member 132 3 0 expanding in length, towards nozzle 110.
_.
Those skilled in the art will understand that a stack of piezoelectric elements may be substituted for illustrated actuator assembly 130. "The actuating force generated by actuator assembly 130 is ultimately transmitted to nozzle 110 through passive hydraulic 5 link assembly 140 and rigid force transmitting members that may be employed between actuator assembly 130 and passive hydraulic link assembly 140, and between passive hydraulic link assembly 140 and nozzle 110.
The '829 Patent discloses a directly actuated injection valve 1 o that employs a piezoelectric or magnetostrictive actuator combined with a passive hydraulic link. The passive hydraulic link employed in preferred embodiments of the present injection valve operates on the same principle as the passive hydraulic link disclosed in the '829 Patent. Passive hydraulic link assembly 140 employs piston 142 15 disposed within a cylinder with closed end 146. Piston stem 142a (indicated in Figure 2) protrudes from an open end of the cylinder.
The cylinder is filled with hydraulic fluid to provide a means fox automatically reseteing the position of nozzle 110 to account for wear and differential thermal expansion of the valve components. Seal 144 2 o prevents the hydraulic fluid from leaking from the cylinder.
During an injection event, when actuator assembly 130 is activated, the hydraulic fluid between closed end 146 and piston 142 does not have time to flow from one side of the piston to the other, so piston 142 maintains its position within the cylinder and the actuation 2 5 forces are transmitted through the hydraulic t~uid layer between closed end 146 and piston 142. Because no significant amount of the hydraulic fluid is displaced during an injection event, the hydraulic fluid acts as a solid in the sense that its thickness between piston 142 and closed end 146, through which the actuation forces are 3 o transmitted, is substantially constant during the injection event. That ..
is, the volume occupied by the hydraulic fluid between piston 142 and closed end 146 remains substantially constant, as does the dimensional shape of that volume.
Compared to the time duration of injection events when fuel 5 injection valve 10U is open, the relatively longer time durations between injection events when fuel injection valve 100 is closed, allows some flow of hydraulic fluid from one side of piston 142 to the other side, which enables the passive hydc-aulic link to self adjust itself when fuel injection valve 100 is closed to account for 1 o dimensional changes caused by wear or differential thermal expansion. While the passive hydraulic Link c.an compensate for such changes in the dimensional relationships between valve components, the functional demands placed upon the passive hydraulic link may be reduced by the selection oi~ materials for the valve components that 15 have similar thermal expansion coefficients.
The actuating force is transmitted from passive hydraulic link assembly 140 through piston stem 142a to rigid member 152, which transmits actuating forces to nozzle 110 through a plurality of rigid members, which extend through open spaces provided within needle 2 0 120. In a preferred embodiment, rigid members 152 are solid cylindrical rods with longitudinal axes parallel to that of nozzle 110 Spring 148 is compressed when fuel injection valve 100 is assembled, and spring 148 ensures that closed end 146 of passive hydraulic link assembly 140 is always in contact with actuator 2 5 assembly 130. Spring 148 may also be employed to provide a compression force to the actuator assembly to increase the potential travel of the magnetostrictive or piezoelectric member. Spring L50 is provided within the cylinder between piston 142 and closed end 146 to ensure that piston stem 142a is always in contact with rigid ,.
members 152, and that rigid members 152 are always in contact with flange 116.
Valve body 102 is shown in the illustrated embodiment as a single piece. In this embodiment, each C>f the internal components is 5 inserted into the valve body through the upper end. Installing an end cap completes assembly oi' the internal comps>nents of fuel injection valve 100. However, to facilitate manufacturing, those skilled in the art would understand that the valve body may be made from a plurality of parts. For example, instead of a single-piece valve body, 1 o there could be two major components, namely an upper valve body, which houses actuator assembly 130 and passive hydraulic link assembly 140, and a lower valve body which houses most of needle 120 and the flanged end of nozzle 110. Those skilled in the art will understand that in such embodiments the exact location of the joint 15 between the upper valve body and lower valve body can be arbitrary without affecting the functionality or operation of fuel injection valve 100. In another variation, a nozzle sleeve can be attached to the needle, which is in turn attached to an upper valve body.
In a specific preferred method of injecting a fuel directly into 2 0 a combustion chamber of an internal combustion engine, the method comprises introducing the fuel into a fuel cavity within an injection valve body, containing the fuel within the fuel cavity by seating a movable nozzle against a sealing surface associate with the injection valve body, commencing an injection event by lifting the movable 2 5 nozzle away from the sealing surface, spacing the nozzle a distance away from the sealing surface for the duration of an injection event, and terminating the injection event by re-seating the movable nozzle against the sealing surface. According to this method, the fuel may be a liquid or gaseous fuel that is cleaner burning compared to diesel 3 0 fuel. Examples of such cleaner burning fuels include, natural gas, ..
methane, propane, ethane, and hydrogen. This preferred method may further comprise shaping the fuel injection rate and/or fuel mass injected during an injection evens by controlling the distance the nozzle is lifted away from the sealing surface and/or the overall 5 duration of the injection event.
While particular elements, embodiments and application,5 of the present invention have been shown and described, it will be understood, of course, that the invention is not limited thereto since modifications may be made by those skilled in the art without 1 o departing from the spirit and scope of the present disclosure, particularly in light of the foregoing teachings.
Further, when the directly injected fuel comprises methane, natural gas, propane, ethane, other gaseous combustible hydrocarbon derivatives, or hydrogen, compared to liquid fuels such as diesel fuel, 2 5 the emissions of NOX a.nd particulate matter (PM) are significantly reduced. The directly injected gaseous fuel can be ignited with a glow plug, with a spark plug or with a small amount of pilot diesel fuel. The gaseous fuel needs to be injected at high pressure to overcome the combustion chamber pressure, which is high at the end 3 0 of the compression stroke (near top dead center). Preferably, the injection pressure is high enough to promote good mixing between the injected fuel and the combustion chamber air. For example, the gaseous fuel injection pressure is preferably at least about 3000 psi (21 MPa); however, this is much less than the pressures typical of 5 diesel-fueled engines, which typically inject liquid diesel fuel into the combustion chamber at pressures of at least about 22,000 psi (150 MPa). Higher pressures are preferred by conventional diesel engines for atomization of the liquid fuel.
Conventional fuel injection valves typically employ a movable 10 needle disposed within an injection valve body. Injection valves normally have a nozzle or injector tip that is held in a fixed position with respect to the injection valve body. Co-owned U.S. Patent No.
6,298,829 (the '829 Patent) discloses an injection valve with such an arrangement. The injection valve described in the '829 Patent is 15 suitable for injecting gaseous fuels directly into the combustion chamber of an internal combustion engine. T"he '829 Patent discloses a valve needle that is lifted away from a seat surface provided in the nozzle of the injection valve. With this arrangement, the fuel is introduced into the injection valve at an end that is opposite to the 2 0 nozzle, and the fuel flows through the valve body, which also houses a piezoelectric or magnetostrictive actuator. While this arrangement may be suitable for fuels such as natural gas, with other gaseous fuels such as hydrogen, it may not be desirable to have the fuel flowing through the whole injection valve body, because such fuels may be 2 5 incompatible with some of the materials of the inner valve components, including the actuator.
Accordingly, it would be an advantage for a fuel injection valve to isolate the fuel from certain valve components, including the actuator assembly.
U.S. Patent No. 5,031,841 (the '841 patent) describes a metering valve using an actuating member, which according to the patent could be a piezoelectric stack or a magnetostrictive actuator.
One feature disclosed by the '841 patent is the addition of a 5 diaphragm which has the dual purpose of acting as a spring, biasing the valve in its closed position, and, of providing a seal between the metered fluid and the actuator. The ' 841 patent discloses an adjusting screw for mechanically setting the position o1' the actuator within the housing. According to the ' 841 patent, the movable valve needle is 1 o rigidly connected to the actuator by a pressure pin. A problem of this design includes the size and shape of the injection valve body necessary to accommodate the diaphragm, as well as the durability requirements of the diaphragm to resist failure.
15 Summary A directly actuated fuel injection valve is provided for injecting a gaseous fuel into a combustion chamber. The injection valve comprises:
(a) a valve body comprising:
2 o a fuel inlet passage; and a fuel cavity fluidly connected to the fuel inlet passage;
(b) a nozzle comprising at least one nozzle orifice through which the gaseous fuel is injectable into the combustion chamber, wherein the nozzle is associated with an end of the valve body and 2 5 movable in relation thereto between:
a closed position, wherein the nozzle is seated against a sealing surface to provide a boundary between the fuel cavity and the at least one nozzle orifice;
an open position, wherein the nozzle is spaced apart 3 o from the sealing surface;
(c) a spring for biasing the nozzle in the closed position;
and (d) an actuator for moving the nozzle to the open position against the bias of the spring.
5 The fuel injection valve preferably further comprises a needle member fixedly associated with the valve body and extending into an interior space within the nozzle. In a preferred arrangement, the sealing surface is associated with the needle member.
The fuel cavity is preferably associated with the nozzle so that l0 it is close to the nozzle orifices. A fuel supply passage for supplying fuel from the fuel inlet passage to the fuel cavity may comprise a fluid passage provided within the needle member.
In preferred embodiments, the combustion chamber is one of a plurality of combustion chambers in a multi-cylinder engine, and 15 the fuel injection valve is preferably one of a plurality of fuel injection valves, each associated with a respective combustion chamber.
The actuator preferably comprises a magnetostrictive or piezoelectric member that expands in a direction that is parallel 'to the 2 0 direction of movement of the nozzle. When a magnetostrictive member is employed, it expands in length when it is subjected to a magnetic field. When a piezoelectric member is employed, it expands in length when it is energized by the application of a voltage to the piezoelectric elements. In a preferred embodiment, the valve 2 5 nozzle, actuated by a magnetostrictive or piezoelectric actuator assembly is controllable to move between the closed and open positions in less than about 250 microseconds.
The magnetostrictive or piezoelectric member is preferably in the shape of a solid cylinder, which may be pre-loaded with a 3 0 compressive force. By pre-loading magnetostrictive members and _.
piezoelectric stacks, net displacement can be increased per respective unit of applied magnetic field or applied voltage. Accordingly, a compression spring member may be employed for applying a compressive force to pre-load the magnetostrictive member or 5 piezoelectric stack. In a preferred embodiment, the compression spring member comprises at least one disc spring (also known as a Belleville spring or Belleville washer).
A magnetostrictive material that is suitable for use in the present injection valve comprises a material known as ETREMA
1 o Terfenol-D~ magnetostrictive alloy that is available from Etrema Products Inc. ETkEMA Terfenol-D~ magnetostrictive alloy is a metal alloy composed of the elements terbium, dysprosium, and iron.
The actuator is preferably housed within a chamber within the valve body that is fluidly isolated from the gaseous fuel.
15 A passive hydraulic link assembly is preferably disposed between the actuator and the nozzle, whereby actuating forces for lifting the nozzle away from the sealing surface are transmitted through the passive hydraulic link assembly. The passive hydraulic link assembly preferably comprises a piston disposed within a fluidly 2 o sealed cylinder that is filled with a liquid.
An advantage of the present injection valve is that it provides an injection valve that eliminates the need for an active hydraulic operator and the associated high-pressure hydraulic system for generating the actuation force to actuate the injection valve.
2 5 Conventional active hydraulic operators are different from the passive hydraulic link of the present invention, which is described as a "passive" hydraulic link because the hydraulic; fluid sealed within the passive hydraulic link assembly merely transmits the actuating forces but is not employed to generate an actuating force for actuating the 3 o valve. During an injection event, there is substantially no flow or displacement of the hydraulic fluid, unlike active hydraulic actuators or systems that use hydraulic amplification chambers that displace hydraulic fluid to amplify an actuation stroke. Rather, the purpose of the passive hydraulic link is to provide a load path for the opposing 5 actuating forces that originate from at least one spring member and the actuator assembly, which preferably comprises a magnetostrictive or piezoelectric element.
In some embodiments, actuating forces are transmitted between the passive hydraulic link assembly and the movable nozzle 1 o through at least one rigid anember may be disposed therebetween.
Such a rigid member may extend through an open space provided within the valve body and/or the needle member. A plurality of rigid members may be employed to distribute the actuating forces over a larger cross-sectional area. In some embodiments, a rigid plate may 15 be disposed between the plurality of rigid members and the nozzle member to help distribute the actuation forcew transmitted through the rigid member(s).
In a preferred embodiment, the nozzle comprises a hollow cylindrical body with an annular shoulder provided in the hollow 2 o interior axially between the nozzle orifice and the fuel cavity for cooperating with a sealing surface associated with the needle member.
The nozzle preferably further comprises a flanged end disposed within the valve body. In this embodiment, the spring for 2 5 biasing the nozzle in the closed position is disposed between a lateral surface of the flanged end and the valve body, whereby the flanged end cooperates with the spring for biasing the nozzle in the closed position.
7 _.
In a specific preferred embodiment of a fuel injection valve for injecting a fuel into a combustion chamber of an internal combustion engine, the injection valve comprises:
(a) a valve body comprising:
5 a fuel inlet passage; and a fuel cavity fluidly connected to the fuel inlet passage;
(b) a needle member fixedly associated with the valve body;
(c) a nozzle comprising at least one nozzle orifice through 1 o which the fuel is injectable into the combustion chamber, the nozzle disposed around the needle member and movable in relation to the needle member between:
a closed position, wherein the nozzle is seated against a sealing surface of the needle member, to provide a boundary 15 between the fuel cavity and the at least one nozzle orifice;
an open position, wherein the nozzle is spaced apart from the sealing surface of the needle member;
(d) a spring for biasing the nozzle in the closed position;
(e) an actuator for moving the nozzle to the open position 2 o against the bias of the spring, the actuator comprising an actuating member that is expandable in a direction parallel to the direction of movement of the nozzle; and (f) a passive hydraulic link assembly disposed between the actuator and the nozzle, whereby actuating forces for lifting the 2 5 nozzle away from the valve needle are transmitted from the actuator through the passive hydraulic link assembly.
Like in the other embodiments, the actuating member preferably comprises a magnetostrictive or piezoelectric material. An advantage of using such materials is that the actuator is controllable 3 o during an injection event to cantrol the speed at which the nozzle _ g ..
moves from the closed position to the open position, in addition to the distance the nozzle is lifted from the sealing surface.
In preferred embodiments, the actuator is housed within a chamber of the valve body that is fluidly isolated from the fuel. In 5 this embodiment, the fuel may be a gaseous or liquid fuel that is a cleaner burning fuel, compared to diesel fuel. Examples of such fuels include natural gas, methane, propane, ethane, and hydrogen.
Isolating the actuator from the fuel is particularly advantageous, with fuels such as hydrogen, which may be reactive with some of the:
10 actuator components.
For ease of manufacture and maintenance servicing, in some embodiments the valve body may comprise a plurality of parts, which are joined with each other to provide a fluidly sealed body. For' example, the valve housing may comprise a hollow upper housing, a 15 hollow lower housing, and a removable needle member. When the removable needle member is installed, it is fixedly associated with the valve body, but if it gets worn down, it can be replaced by separating the upper and lower housings and removing the needle member.
A method is provided of injecting a gaseous fuel into a 2 o combustion chamber of an internal combustion engine. The method comprises introducing a gaseous fuel into a fuel cavity within an injection valve body;
containing the gaseous fuel within the fuel cavity by 2 5 seating a movable nozzle against a sealing surface associated with the injection valve body;
commencing an injection event by lifting the movable nozzle away from the sealing surface; and terminating an injection event by re-seating the 3 o movable nozzle against the sealing surface.
_ g _ In a preferred method the gaseous fuel is delivered to the fuel cavity from a common rail fuel supply system. The fuel pressure within the fuel cavity is preferably at least about 1000 psi (about 6.9 MPa), and more preferably greater than about 2000 psi (greater than 5 about 13.8 MPa) when the engine is operating.
The preferred method further comprises lifting the movable nozzle away from the sealing surface for the duration of an injection event, and controlling the speed of nozzle movement between the open and closed positions as well as the distance the nozzle is lifted 1 o from the sealing surface. By controlling nozzle movement in these ways, and the overall duration of the injection event, the mass of the gaseous fuel that is injected into the combustion chamber during an injection event can be controlled, and the timing for injecting the fuel can be controlled in accordance with predetermined "rate shapes" . In 15 a preferred method the rate shape and mass flow rates can be determined based upon a measured engine operating parameter.
These and other advantages are provided by a directly actuated fuel injection valve with a movable nozzle as described below.
Brief Description Of The Drawings Figure 1 is a cross-sectional view of a preferred embodiment of a directly actuated fuel injection valve with a movable nozzle; and Figure 2 is an enlarged cross-sectional view of the nozzle end 2 5 of the fuel injection valve of Figure l .
Detailed Description Of Preferred Embodiment(S) A preferred embodiment of gaseous fuel injection valve 100 with movable nozzle 110 will be described with reference to Figures 3 0 1 and 2. Figures 1 and 2 are both cross-sectional views with Figure 2 being an enlarged detailed view of the nozzle end of fuel injection valve 100.
Fuel injection valve 100 comprises a valve body 102, which comprises fuel inlet passage 104 and fuel cavity 106, which is fluidly 5 connected to fuel inlet passage 104. Fuel cavity 106 comprises an annular space between needle 120 and nozzle 110. Fuel inlet passage 104 may comprise passages provided within valve body 102 and needle 120, and in spaces defined therebetween. For example, in the illustrated embodiment, fuel inlet passage 104 comprises bore 1;Z2 1 o and branches 124 and 126 provided within an upper portion of needle 120, through which gaseous fuel may flow on its way to fuel cavity 106. Preferably the fuel passages are constructed so that gaseous fuel may flow through fuel inlet passage 104 to fuel cavity 106 without contacting actuator assembly 130 or passive hydraulic link assembly 15 140. Seals such as o-ring seals 108 fluidly isolate the pressurized fuel passages from passive hydraulic link assembly 140. Seal 109 prevents gaseous fuel from escaping from fuel cavity 106, through the gap between nuzzle 110 and needle 120. Different types of seals known to those skilled in the art may be employed instead of the; o-2 o ring seals that are shown in Figures 1 and 2 for illustrative purposes.
As shown in the illustrated embodiment, needle 120 is fixedly associated with valve body 102. Preferably needle 120 is a removable component so that it can be replaced if the sealing surface becomes worn. Manufacturing needle 120 as a separate component 2 5 also facilitates the manufacturing of the (uel passages for supplying the gaseous fuel to fuel cavity 106. Unlike conventional gaseous fuel injection valves, once assembled, installed, and operational, needle 120 is stationary with respect to valve body 102.
Nozzle 110 comprises at least one nozzle orifice 112 through 3 o which gaseous fuel is injectable into a combustion chamber.
- ~_ 1 ._ Preferably, the tip of nozzle 11U that extends out of the valve body is the only part of fuel injection valve 100 that is directly exposed to the engine combustion chamber, with most of valve body 102 disposed within the engine cylinder head or above the cylinder head.
5 Nozzle L 10 is movable with respect tc> valve body 102 and needle 120. Fuel injection valve 100 is closed when nozzle 110 is seated against a sealing surface of needle 120, and is opened when nozzle 110 is lifted away from the sealing surface in the direction of the combustion chamber, defined herein as the outward direction. In 1 o the illustrated embodiment, the sealing surface is that portion of needle 120, which contacts nozzle 110 when nozzle 110 is urged towards needle 120. When nozzle 110 moves from an open position to a closed position, this direction of movement is defined herein as inward movement. When nozzle 110 is seated against needle 120 a 15 fluid tight boundary is formed between fuel cavity 106 and nozzle orifices) 112.
Controlling the distance nozzle 110 is lifted away from the sealing surface of needle 120, during an injection event, can influence the rate of injecting gaseous fuel into the combustion chamber.
2 o Generally, the greater the distance that nozzle 110 is lifted away from the sealing surface, the greater the mass flow rate of gaseous fuel into the combustion chamber. An upper limit on mass flow rate is eventually reached when the open area of the nozzle orifices limits the flow.
2 5 The timing far injecting gaseous fuel during an injection event can also be controlled by changing the lift distance and fuel mass flow rate during an injection event. 'This technique is defined herein as "rate shaping" because nozzle lift is controllable to influence the mass flow rate of gaseous fuel injection into tike combustion chamber.
3 o Rate shaping is made possible by employing an actuator assembly 130 comprising magnetostrictive or piezoelectric .elements to directly actuate nuzzle 110. Conventional hydraulically actuated injection valves du not have the same capability for rate shaping as directly actuated injection valves.
5 Spring 114 is disposed between an annular shoulder provided by valve body 102 and flange 116 of nozzle 110. With the illustrated arrangement, spring 114 biases nozzle 110 in the closed position.
Spring 114 is illustrated as a disc spring, which is also known as a Belleville washer or Belleville spring. As thaw skilled in the art 1 o would understand, other types of springs may be substituted to achieve substantially the same result.
The illustrated embodiment of actuator assembly 130 comprises solid magnetostrictive member 132. The cross-sectional area of magnetostrictive member 132 is dictated by the force 15 necessary to overcome all of the opposing forces that hold nozzle 110 in the closed position. A greater crass-sectional area results in larger opening forces. Because the crass-sectic~c~al area of magnetostrictive member 132 is solid, its diameter can be smaller than the diameter of the tubular magnetostrictive member disclosed in the '829 Patent 2 o referred to above. Employing known manufacturing techniques, a solid rod is also much easier to manufacture compared to a tubular member.
Spool 134 holds electric coil 136. Flux tube 138 surrounds electric coil 136 and spool 134. Flux tube 138 can have a lengthwise 25 slit to break eddy currents. To activate the actuator, an electric current is supplied to energize electric Gail 136, causing a magnetic flux to develop that flows through magnetostrictive member 132.
When a magnetic flux flows through magnetastrictive member 132 an actuating farce is generated by magnetastrict~ve member 132 3 0 expanding in length, towards nozzle 110.
_.
Those skilled in the art will understand that a stack of piezoelectric elements may be substituted for illustrated actuator assembly 130. "The actuating force generated by actuator assembly 130 is ultimately transmitted to nozzle 110 through passive hydraulic 5 link assembly 140 and rigid force transmitting members that may be employed between actuator assembly 130 and passive hydraulic link assembly 140, and between passive hydraulic link assembly 140 and nozzle 110.
The '829 Patent discloses a directly actuated injection valve 1 o that employs a piezoelectric or magnetostrictive actuator combined with a passive hydraulic link. The passive hydraulic link employed in preferred embodiments of the present injection valve operates on the same principle as the passive hydraulic link disclosed in the '829 Patent. Passive hydraulic link assembly 140 employs piston 142 15 disposed within a cylinder with closed end 146. Piston stem 142a (indicated in Figure 2) protrudes from an open end of the cylinder.
The cylinder is filled with hydraulic fluid to provide a means fox automatically reseteing the position of nozzle 110 to account for wear and differential thermal expansion of the valve components. Seal 144 2 o prevents the hydraulic fluid from leaking from the cylinder.
During an injection event, when actuator assembly 130 is activated, the hydraulic fluid between closed end 146 and piston 142 does not have time to flow from one side of the piston to the other, so piston 142 maintains its position within the cylinder and the actuation 2 5 forces are transmitted through the hydraulic t~uid layer between closed end 146 and piston 142. Because no significant amount of the hydraulic fluid is displaced during an injection event, the hydraulic fluid acts as a solid in the sense that its thickness between piston 142 and closed end 146, through which the actuation forces are 3 o transmitted, is substantially constant during the injection event. That ..
is, the volume occupied by the hydraulic fluid between piston 142 and closed end 146 remains substantially constant, as does the dimensional shape of that volume.
Compared to the time duration of injection events when fuel 5 injection valve 10U is open, the relatively longer time durations between injection events when fuel injection valve 100 is closed, allows some flow of hydraulic fluid from one side of piston 142 to the other side, which enables the passive hydc-aulic link to self adjust itself when fuel injection valve 100 is closed to account for 1 o dimensional changes caused by wear or differential thermal expansion. While the passive hydraulic Link c.an compensate for such changes in the dimensional relationships between valve components, the functional demands placed upon the passive hydraulic link may be reduced by the selection oi~ materials for the valve components that 15 have similar thermal expansion coefficients.
The actuating force is transmitted from passive hydraulic link assembly 140 through piston stem 142a to rigid member 152, which transmits actuating forces to nozzle 110 through a plurality of rigid members, which extend through open spaces provided within needle 2 0 120. In a preferred embodiment, rigid members 152 are solid cylindrical rods with longitudinal axes parallel to that of nozzle 110 Spring 148 is compressed when fuel injection valve 100 is assembled, and spring 148 ensures that closed end 146 of passive hydraulic link assembly 140 is always in contact with actuator 2 5 assembly 130. Spring 148 may also be employed to provide a compression force to the actuator assembly to increase the potential travel of the magnetostrictive or piezoelectric member. Spring L50 is provided within the cylinder between piston 142 and closed end 146 to ensure that piston stem 142a is always in contact with rigid ,.
members 152, and that rigid members 152 are always in contact with flange 116.
Valve body 102 is shown in the illustrated embodiment as a single piece. In this embodiment, each C>f the internal components is 5 inserted into the valve body through the upper end. Installing an end cap completes assembly oi' the internal comps>nents of fuel injection valve 100. However, to facilitate manufacturing, those skilled in the art would understand that the valve body may be made from a plurality of parts. For example, instead of a single-piece valve body, 1 o there could be two major components, namely an upper valve body, which houses actuator assembly 130 and passive hydraulic link assembly 140, and a lower valve body which houses most of needle 120 and the flanged end of nozzle 110. Those skilled in the art will understand that in such embodiments the exact location of the joint 15 between the upper valve body and lower valve body can be arbitrary without affecting the functionality or operation of fuel injection valve 100. In another variation, a nozzle sleeve can be attached to the needle, which is in turn attached to an upper valve body.
In a specific preferred method of injecting a fuel directly into 2 0 a combustion chamber of an internal combustion engine, the method comprises introducing the fuel into a fuel cavity within an injection valve body, containing the fuel within the fuel cavity by seating a movable nozzle against a sealing surface associate with the injection valve body, commencing an injection event by lifting the movable 2 5 nozzle away from the sealing surface, spacing the nozzle a distance away from the sealing surface for the duration of an injection event, and terminating the injection event by re-seating the movable nozzle against the sealing surface. According to this method, the fuel may be a liquid or gaseous fuel that is cleaner burning compared to diesel 3 0 fuel. Examples of such cleaner burning fuels include, natural gas, ..
methane, propane, ethane, and hydrogen. This preferred method may further comprise shaping the fuel injection rate and/or fuel mass injected during an injection evens by controlling the distance the nozzle is lifted away from the sealing surface and/or the overall 5 duration of the injection event.
While particular elements, embodiments and application,5 of the present invention have been shown and described, it will be understood, of course, that the invention is not limited thereto since modifications may be made by those skilled in the art without 1 o departing from the spirit and scope of the present disclosure, particularly in light of the foregoing teachings.
Claims (45)
1. A fuel injection valve for injecting a gaseous fuel into a combustion chamber, said injection valve comprising:
(a) a valve body that comprises:
a fuel inlet passage; and a fuel cavity fluidly connected to said fuel inlet passage;
(b) a nozzle comprising at least one nozzle orifice through which said gaseous fuel is injectable into said combustion chamber, wherein said nozzle is associated with an end of said valve body and movable in relation thereto between:
a closed position, wherein said nozzle is seated against a sealing surface to provide a boundary between said fuel cavity and said at least one nozzle orifice;
an open position, wherein said nozzle is spaced apart from said sealing surface;
(c) a spring for biasing said nozzle in said closed position;
and (d) an actuator for moving said nozzle to said open position against the bias of said spring.
(a) a valve body that comprises:
a fuel inlet passage; and a fuel cavity fluidly connected to said fuel inlet passage;
(b) a nozzle comprising at least one nozzle orifice through which said gaseous fuel is injectable into said combustion chamber, wherein said nozzle is associated with an end of said valve body and movable in relation thereto between:
a closed position, wherein said nozzle is seated against a sealing surface to provide a boundary between said fuel cavity and said at least one nozzle orifice;
an open position, wherein said nozzle is spaced apart from said sealing surface;
(c) a spring for biasing said nozzle in said closed position;
and (d) an actuator for moving said nozzle to said open position against the bias of said spring.
2. The fuel injection valve of claim 1 further comprising a needle member fixedly associated with said valve body and extending into an interior space within said nozzle.
3. The fuel injection valve of claim 2 wherein said sealing surface is associated with said needle member.
4. The fuel injection valve of claim 2 wherein a fuel supply passage for supplying fuel from said fuel inlet passage to said fuel cavity comprises a fluid passage provided within said needle member.
5. The fuel injection valve of claim 1 wherein said combustion chamber is one of a plurality of combustion chambers in an internal combustion engine.
6. The fuel injection valve of claim 1 wherein said actuator comprises a magnetostrictive member that expands in a direction that is parallel to the direction of movement of said nozzle when said magnetostrictive member is subjected to a magnetic field.
7. The fuel injection valve of claim 6 wherein said magnetostrictive member is in the shape of a solid cylinder.
8. The fuel injection valve of claim 6 wherein said magnetostrictive member is pre-loaded with a compressive force.
9. The fuel injection valve of claim 1 wherein said actuator comprises an elongated stack of piezoelectric elements, wherein said stack expands in length when said piezoelectric elements are energized.
10. The fuel injection valve of claim 9 wherein said piezoelectric stack is pre-loaded with a compressive force.
11. The fuel injection valve of claim 1 wherein said actuator is housed within said valve body within a chamber that is fluidly isolated from said gaseous fuel.
12. The fuel injection valve of claim 1 further comprising a passive hydraulic link assembly disposed between said actuator and said nozzle, whereby actuating forces for lifting said nozzle away from said sealing surface are transmitted through said passive hydraulic link assembly.
13. The fuel injection valve of claim 12 wherein said passive hydraulic link assembly comprises a piston disposed within a fluidly sealed cylinder filled with a liquid.
14. The fuel injection valve of claim 13 further comprising at least one rigid member disposed between said passive hydraulic link assembly and said nozzle, for transmitting actuating forces therebetween.
15. The fuel injection valve of claim 14 wherein said at least one rigid member extends through an open space provided within said valve body.
16. The fuel injection valve of claim 14 wherein said at least one rigid member extends through an open space provided within a needle member that extends into an interior space within said nozzle, and is fixedly associated with said valve body.
17. The fuel injection valve of claim 13 further comprising a plurality of rigid members disposed between said passive hydraulic link assembly and said nozzle for transmitting actuating forces therebetween, said plurality of rigid members each extending through an open space provided within at least one of said valve body and a needle member that extends into an interior space within said nozzle, and is fixedly associated with said valve body.
18. The fuel injection valve of claim 17 further comprising a rigid plate disposed between said plurality of rigid members and said nozzle.
19. The fuel injection valve of claim 1 wherein said nozzle comprises a hollow cylindrical body with an annular shoulder provided in the hollow interior axially between said at least one nozzle orifice and said fuel cavity for cooperating with said sealing surface.
20. The fuel injection valve of claim 19 wherein said nozzle further comprises a flanged end disposed within said valve body, said flanged end cooperating with said spring for biasing said nozzle in said closed position.
21. A fuel injection valve for injecting a fuel into a combustion chamber, said injection valve comprising:
(a) a valve body that comprises:
a fuel inlet passage; and a fuel cavity fluidly connected to said fuel inlet passage;
(b) a needle member fixedly associated with said valve body;
(c) a nozzle comprising at least one nozzle orifice through which said fuel is injectable into said combustion chamber, said nozzle disposed around said needle member and movable in relation to said needle member between:
a closed position, wherein said nozzle is seated against a sealing surface of said needle member, to provide a boundary between said fuel cavity and said at least one nozzle orifice;
an open position, wherein said nozzle is spaced apart from said sealing surface of said needle member;
(d) a spring for biasing said nozzle in said closed position;
(e) an actuator for moving said nozzle to said open position against the bias of said spring, said actuator comprising an actuating member that is expandable in a direction parallel to the direction of movement of said nozzle; and (f) a passive hydraulic link assembly disposed between said actuator and said nozzle, whereby actuating forces for lifting said nozzle away from said valve needle are transmitted from said actuator through said passive hydraulic link assembly.
(a) a valve body that comprises:
a fuel inlet passage; and a fuel cavity fluidly connected to said fuel inlet passage;
(b) a needle member fixedly associated with said valve body;
(c) a nozzle comprising at least one nozzle orifice through which said fuel is injectable into said combustion chamber, said nozzle disposed around said needle member and movable in relation to said needle member between:
a closed position, wherein said nozzle is seated against a sealing surface of said needle member, to provide a boundary between said fuel cavity and said at least one nozzle orifice;
an open position, wherein said nozzle is spaced apart from said sealing surface of said needle member;
(d) a spring for biasing said nozzle in said closed position;
(e) an actuator for moving said nozzle to said open position against the bias of said spring, said actuator comprising an actuating member that is expandable in a direction parallel to the direction of movement of said nozzle; and (f) a passive hydraulic link assembly disposed between said actuator and said nozzle, whereby actuating forces for lifting said nozzle away from said valve needle are transmitted from said actuator through said passive hydraulic link assembly.
22. The fuel injection valve of claim 21 wherein said actuating member comprises a magnetostrictive material.
23. The fuel injection valve of claim 22 wherein said magnetostrictive material is a metal alloy comprising the elements terbium, dysprosium, and iron.
24. The fuel injection valve of claim 21 wherein said actuating member comprises a stack of piezoelectric elements.
25. The fuel injection valve of claim 21 wherein said actuator is housed within a chamber of said valve body that is fluidly isolated from said fuel.
26. The fuel injection valve of claim 21 wherein said fuel is selected from the group consisting of natural gas, methane, propane, ethane, and hydrogen.
27. The fuel injection valve of claim 21 wherein said actuator is controllable during an injection event to control the speed at which said nozzle moves from said closed position to said open position.
28. The fuel injection valve of claim 21 wherein said actuator is controllable during an injection event to control the distance said nozzle is lifted from said sealing surface up to a maximum distance.
29. The fuel injection valve of claim 21 wherein said valve body comprises a plurality of parts which are joined with each other to provide a fluidly sealed body.
30. The fuel injection valve of claim 21 wherein said fuel cavity is disposed within an end of said valve body that is associated with said nozzle.
31. The fuel injection valve of claim 30 wherein said fuel cavity comprises an annular space between said needle member and said nozzle.
32. A method of injecting a gaseous fuel into a combustion chamber of an internal combustion engine, said method comprising:
introducing said gaseous fuel into a fuel cavity within an injection valve body;
containing said gaseous fuel within said fuel cavity by seating a movable nozzle against a sealing surface associated with said injection valve body;
commencing an injection event by lifting said movable nozzle away from said sealing surface; and terminating said injection event by re-seating said movable nozzle against said sealing surface.
introducing said gaseous fuel into a fuel cavity within an injection valve body;
containing said gaseous fuel within said fuel cavity by seating a movable nozzle against a sealing surface associated with said injection valve body;
commencing an injection event by lifting said movable nozzle away from said sealing surface; and terminating said injection event by re-seating said movable nozzle against said sealing surface.
33. The method of claim 32 further comprising delivering said gaseous fuel to said fuel cavity from a common rail fuel supply system.
34. The method of claim 33 further comprising maintaining a fuel pressure within said fuel cavity of at least about 2000 psi about 13.8 MPa) when said engine is operating.
35. The method of claim 32 further comprising actuating said movable nozzle with an actuator comprising an elongated material that is expandable in length to provide the actuating force to lift said movable nozzle from said sealing surface.
36. The method of claim 35 further comprising fluidly isolating said gaseous fuel from said actuator.
37. The method of claim 35 further comprising transmitting actuating forces from said actuator to said nozzle through a passive hydraulic link assembly.
38. The method of claim 32 further comprising lifting said nozzle away from said sealing surface for the duration of an injection event.
39. The method of claim 38 further comprising shaping the fuel injection rate during an injection event by controlling the distance said nozzle is lifted away from said sealing surface.
40. The method of claim 38 further comprising controlling the mass of said gaseous fuel that is injected into said combustion chamber during an injection event by controlling the distance said nozzle is lifted away from said sealing surface during said injection event and the overall duration of said injection event.
41. A method of injecting a fuel directly into a combustion chamber of an internal combustion engine, said method comprising:
introducing said fuel into a fuel cavity within an injection valve body;
containing said fuel within said fuel cavity by seating a movable nozzle against a sealing surface associated with said injection valve body;
commencing an injection event by lifting said movable nozzle away from said sealing surface;
spacing said nozzle a distance away from said sealing surface for the duration of said injection event; and terminating said injection event by re-seating said movable nozzle against said sealing surface.
introducing said fuel into a fuel cavity within an injection valve body;
containing said fuel within said fuel cavity by seating a movable nozzle against a sealing surface associated with said injection valve body;
commencing an injection event by lifting said movable nozzle away from said sealing surface;
spacing said nozzle a distance away from said sealing surface for the duration of said injection event; and terminating said injection event by re-seating said movable nozzle against said sealing surface.
42. The method of claim 41 wherein said fuel is gaseous.
43. The method of claim 41 wherein said fuel is selected from the group consisting of natural gas, methane, propane, ethane, and hydrogen.
44. The method of claim 41 further comprising shaping the fuel injection rate during an injection event by controlling the distance said nozzle is lifted away from said sealing surface.
45. The method of claim 41 further comprising controlling the mass of said gaseous fuel that is injected into said combustion chamber during an injection event by controlling the distance said nozzle is lifted away from said sealing surface during said injection event and the overall duration of said injection event.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002406883A CA2406883C (en) | 2002-10-09 | 2002-10-09 | Directly actuated gaseous fuel injection valve with a movable nozzle |
| PCT/CA2003/001552 WO2004033892A1 (en) | 2002-10-09 | 2003-10-08 | Directly actuated gaseous fuel injection valve with a movable nozzle |
| AU2003273698A AU2003273698A1 (en) | 2002-10-09 | 2003-10-08 | Directly actuated gaseous fuel injection valve with a movable nozzle |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002406883A CA2406883C (en) | 2002-10-09 | 2002-10-09 | Directly actuated gaseous fuel injection valve with a movable nozzle |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2406883A1 CA2406883A1 (en) | 2003-01-22 |
| CA2406883C true CA2406883C (en) | 2004-02-24 |
Family
ID=4171230
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002406883A Expired - Fee Related CA2406883C (en) | 2002-10-09 | 2002-10-09 | Directly actuated gaseous fuel injection valve with a movable nozzle |
Country Status (3)
| Country | Link |
|---|---|
| AU (1) | AU2003273698A1 (en) |
| CA (1) | CA2406883C (en) |
| WO (1) | WO2004033892A1 (en) |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4306072C2 (en) * | 1993-02-26 | 1994-12-08 | Siemens Ag | Device for opening and closing a passage opening in a housing |
| DE19838862A1 (en) * | 1998-08-26 | 2000-03-09 | Siemens Ag | Rapid mixing injection valve for internal combustion engine |
| DE10042570A1 (en) * | 2000-08-25 | 2002-03-14 | Univ Dresden Tech | Fuel injector for internal combustion engine has injector opening stroke controlled by piezo actuator |
-
2002
- 2002-10-09 CA CA002406883A patent/CA2406883C/en not_active Expired - Fee Related
-
2003
- 2003-10-08 AU AU2003273698A patent/AU2003273698A1/en not_active Abandoned
- 2003-10-08 WO PCT/CA2003/001552 patent/WO2004033892A1/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| AU2003273698A1 (en) | 2004-05-04 |
| CA2406883A1 (en) | 2003-01-22 |
| WO2004033892A1 (en) | 2004-04-22 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |