EP3219974A1 - Fuel injector - Google Patents
Fuel injector Download PDFInfo
- Publication number
- EP3219974A1 EP3219974A1 EP17161355.7A EP17161355A EP3219974A1 EP 3219974 A1 EP3219974 A1 EP 3219974A1 EP 17161355 A EP17161355 A EP 17161355A EP 3219974 A1 EP3219974 A1 EP 3219974A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- fuel
- valve needle
- valve
- bore
- restriction
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
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- 239000000446 fuel Substances 0.000 title claims abstract description 163
- 238000002485 combustion reaction Methods 0.000 claims abstract description 17
- 235000014676 Phragmites communis Nutrition 0.000 claims description 19
- 230000000717 retained effect Effects 0.000 claims description 3
- 238000011144 upstream manufacturing Methods 0.000 description 17
- 230000002441 reversible effect Effects 0.000 description 4
- 238000013016 damping Methods 0.000 description 3
- 238000002347 injection Methods 0.000 description 3
- 239000007924 injection Substances 0.000 description 3
- 230000002829 reductive effect Effects 0.000 description 3
- 239000000853 adhesive Substances 0.000 description 2
- 230000001070 adhesive effect Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000000670 limiting effect Effects 0.000 description 2
- 238000013459 approach Methods 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000036316 preload Effects 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
Images
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
- F02M47/00—Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure
- F02M47/02—Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure of accumulator-injector type, i.e. having fuel pressure of accumulator tending to open, and fuel pressure in other chamber tending to close, injection valves and having means for periodically releasing that closing pressure
- F02M47/027—Electrically actuated valves draining the chamber to release the closing pressure
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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
- 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
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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
- F02M51/00—Fuel-injection apparatus characterised by being operated electrically
- F02M51/06—Injectors peculiar thereto with means directly operating the valve needle
-
- 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
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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
- 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
- F02M61/10—Other injectors with elongated valve bodies, i.e. of needle-valve type
- F02M61/12—Other injectors with elongated valve bodies, i.e. of needle-valve type characterised by the provision of guiding or centring means for valve bodies
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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
- F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
- F02M2200/28—Details of throttles in fuel-injection apparatus
-
- 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
- F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
- F02M2200/30—Fuel-injection apparatus having mechanical parts, the movement of which is damped
- F02M2200/304—Fuel-injection apparatus having mechanical parts, the movement of which is damped using hydraulic means
Definitions
- the present invention relates to a fuel injector for use in delivering high pressure fuel to an internal combustion engine.
- the invention relates to a fuel injector for use in a compression ignition internal combustion engine.
- a direct acting injector an actuator is coupled directly to the valve needle to control needle movement.
- Both piezoelectric and electromagnetic direct acting injectors are known.
- a solenoid-operated actuator controls movement of a plunger by applying a current through a solenoid.
- the plunger acts on a chamber of fuel arranged at the upper end of a valve needle so that, through a hydraulic amplifier, the force of the plunger is transmitted to the valve needle.
- By varying the force applied to the valve needle movement of the valve needle towards and away from a valve needle seat is controlled.
- valve needle movement is controlled differently, through an intermediate servo-valve which is operated by the actuator.
- the seat for the valve needle is typically defined by a frustoconical surface at the end of a bore provided in a nozzle body.
- An aspect of the invention provides a fuel injector for use in an internal combustion engine, the fuel injector comprising a nozzle body having a bore for receiving fuel from a supply line for pressurised fuel, an outlet from the bore for delivering fuel to the combustion cylinder, in use, a valve needle slidable within the bore between a closed position in which fuel flow through the outlet into the combustion chamber is prevented, and an open position in which fuel flow through the outlet into the combustion chamber is enabled, wherein the valve needle carries a restrictive element providing at least one restriction for restricting the flow of fuel through the bore such that, during opening movement of the valve needle, fuel pressure downstream of the restrictive element is less than a pressure of fuel supplied to the bore from the supply line; and at least one valve device which is operable in response to a pressure difference across the restrictive element so as to allow a flow of fuel through the at least one restriction during opening movement of the valve needle but to further restrict the flow of fuel through the at least one restriction during a final phase of closing movement of the valve needle, thereby to damp said final phase of closing
- the restrictive element acts to impart a net downward force to the valve needle during opening movement of the valve needle to thereby control the speed at which the valve needle moves towards its point of maximum lift.
- the at least one valve device enables a higher pressure to be maintained in the portion of the bore downstream of the restrictive element than would be possible without the at least one valve device, thereby enabling the restrictive element to impart a greater net upward force to the valve needle than would be possible without the at least one valve device in order to provide a greater damping effect, thereby reducing the impact force of the valve needle against the nozzle seat and minimising wear of the valve needle tip and the nozzle seat.
- the final phase of closing movement (when fuel would otherwise flow in reverse through the at least one restriction from the portion of the bore downstream of the restrictive element to the portion of the bore upstream of the restrictive element), is typically the very end of closing movement of the valve needle, just before the valve needle is seated.
- the at least one valve device may be arranged to further restrict the flow of fuel through the at least one restriction during the final phase of closing movement of the valve needle which may be over approximately the final 30%, or over approximately the final 20%, or over approximately the final 10% of the valve needle's travel towards the closed position, in normal use of the fuel injector.
- This final phase of closing movement may be considered to be the very end of closing movement, just before the valve needle is seated, and during which phase, without the presence of the valve device(s), fuel would otherwise flow in reverse through the at least one restriction from the portion of the bore downstream of the restrictive element to the portion of the bore upstream of the restrictive element. This is, typically, for example, over approximately the final 20% or so (e.g. between about the final 17% and about the final 23%) of closing movement of the valve needle (i.e. until it seats).
- the at least one valve device may not act to further restrict the flow of fuel through the at least one restriction (or may only further restrict the flow of fuel to a lesser extent) prior to approximately the final 30% (or approximately the final 20%, or approximately the final 10%) of the valve needle's travel towards the closed position, in normal use of the fuel injector. In this case the at least one valve device may not act to significantly reduce the closing speed of the valve needle until approximately the final 30% (or approximately the final 20%, or approximately the final 10%) of the valve needle's travel towards the closed position.
- the fuel injector may be a diesel injector or a gasoline injector.
- the at least one valve device may be located downstream of the restrictions provided by the restrictive element.
- the at least one valve device may comprise at least one valve element that is arranged to cover at least one of the restrictions when in a closed position to further restrict the flow of fuel through the at least one restriction.
- the at least one valve element may comprise at least one aperture for allowing a further restricted fuel flow through the at least one restriction when in the closed position.
- the dimensions of the aperture(s) may be selected in order to tune the degree of further restriction for a desired operating characteristic of the fuel injector.
- the at least one valve element may be arranged to further restrict the flow of fuel through the at least one restriction by completely preventing fuel flow through the at least one restriction when in its closed position. In this case no aperture as described above is present in the valve element.
- the at least one valve element may comprise at least one reed valve element.
- the at least one valve element may extend either radially inwardly or radially outwardly from an annular ring.
- the annular ring may be attached to the restrictive element and/or to the valve needle, for example by an adhesive or spot weld(s).
- valve element(s) may be attached to the restrictive element and/or to the valve needle individually, for example by an adhesive or spot weld(s).
- the at least one valve element may comprise an annular disc that is biased towards the restrictive element.
- the annular disc may be biased towards the restrictive device by a spring.
- the spring may be retained by a shoulder provided on the valve needle.
- the restrictive element is preferably fixed with respect to the valve needle.
- the restrictive element may comprise an annular collar attached to or integrally formed with the valve needle.
- a degree of relative movement between the valve needle and the restrictive element may be possible e.g. so that the restrictive element is 'floating'.
- the at least one restriction may take the form of at least one orifice extending through the thickness of the restrictive element and/or at least one groove provided in an outer surface of the restrictive element.
- the area of the orifice in the restrictive element may be around 7 times greater than the area of the fuel injector outlet(s), and may be around 30 times smaller than the area of the bore.
- the combined cross-sectional area of the aperture(s) may be significantly less than 50% of the combined cross sectional area of the restriction(s) and/or significantly less than 25% of the combined cross-sectional area of the outlet(s). Other values are also possible. It will be appreciated that the relative dimensions of the bore, the restrictive element, the restriction(s), the aperture(s) and the outlet(s) may be varied in order to select the desired damping performance.
- references to upper, lower, upward, downward, above and below, for example, are not intended to be limiting and relate only to the orientation of the injector as shown in the illustration.
- the present invention relates to a fuel injector 100 of the type generally shown in Figure 1 .
- the fuel injector 100 is suitable for use in a fuel injection system of an internal combustion engine, and particularly a diesel engine in which fuel is typically injected into the engine at high pressure levels in excess of 2000 bar, and commonly as high as 3000 bar.
- the fuel injector 100 comprises a valve needle 1 that is slidable within a bore 2 of a nozzle body 3.
- a proximal end of the nozzle body 3 is coupled to a piston guide 4.
- the proximal end of the bore receives high pressure fuel, in use, from a supply line 5 provided in the piston guide.
- the bore includes a section of comparatively small diameter 2a towards its distal end and a section of comparatively large diameter 2b towards its proximal end.
- the bore 2 at its distal end, defines a nozzle seat 6 of generally frusto-conical form with which a tip 7 of the valve needle 1 is engageable. Downstream of the nozzle seat 6, the nozzle body is provided with a plurality of outlets 8 for delivering fuel to a combustion cylinder, in use.
- the tip 7 of the valve needle When the valve needle 1 is in its closed position, the tip 7 of the valve needle is engaged with the nozzle seat 6 to prevent fuel from being delivered from the bore 2 through the outlets 8. However, when the valve needle 1 is lifted away from the nozzle seat 6, as described below, the tip 7 of the valve needle 1 moves out of engagement with the nozzle seat 6 to allow fuel to be delivered from the bore 2 through the outlets 8.
- a spring 9 is provided towards a proximal end of the valve needle 1, which acts to urge the valve needle 1 towards its closed position.
- the valve needle 1 comprises a valve needle guide 10 towards its distal end.
- the valve needle guide 10 slidingly engages the bore 2 in the section of comparatively small diameter 2a to prevent lateral movement of the valve needle 1 within the bore.
- the valve needle guide 10 includes a plurality of grooves to permit the passage of fuel past the valve needle guide.
- the valve needle 1 also comprises a proximal guide portion 11 at is proximal end that slidingly engages the piston guide 4 to prevent lateral movement of the valve needle 1 within the bore 2.
- the valve needle 1 is provided with a plurality of thrust surfaces 12 of generally frustoconical form that are exposed to fuel pressure within the bore 2 in order to provide an upward force to urge the valve needle 1 away from its closed position.
- the valve needle 1 is further provided with a restrictive element 20 (shown more clearly in Fig. 2 ) in the form of an annular collar extending around the valve needle and located within the bore 2 in the section of comparatively large diameter 2b.
- the restrictive element 20 is fixed with respect to the valve needle, and may be integrally formed with the valve needle 1, or alternatively may be a separate component that is attached to the valve needle (for example by press fitting).
- the restrictive element is arranged to move together with the valve needle as the valve needle slides within the bore 2.
- the restrictive element 20 has a diameter that is slightly smaller than that of the bore 2 at the section of comparatively large diameter 2b and so extends almost up the side-wall of the bore.
- the restrictive element 20 divides the bore 2 into a portion located upstream of the restrictive element (the upstream portion) and a portion located downstream of the restrictive element (the downstream portion).
- the restrictive element 20 comprises an upper surface 20a facing towards the proximal end of the bore, and a lower surface 20b facing towards the distal end of the bore.
- the restrictive element 20 acts to restrict the flow of fuel through the bore 2 such that the fuel pressure downstream of the restriction is generally less than a pressure of fuel supplied to the bore 2 from the supply line 5 during opening movement of the valve needle, as described below.
- the restrictive element 20 is provided with a plurality of passages or orifices 21 extending through its thickness to allow the restricted flow of fuel through the restrictive element 20 and through the bore 2.
- the orifices 21 act as a plurality of restrictions because the combined cross-sectional area of the orifices is significantly smaller than the cross-sectional area of the bore 2.
- the orifices 21 are spaced around the restrictive element 20 in a circle.
- the number and spatial arrangement of the orifices 21 is not critical, and that in other embodiments there may only be one orifice.
- the restrictive element 20 is provided with a valve device 30 (not shown in Figure 1 but illustrated in Figures 4 to 6 ).
- the valve device 30 comprises an annular ring 31 that surrounds the valve needle 1 and is spot welded to the valve needle and/or to the lower surface of the restrictive element and/or held between the restrictive element 20 and a shoulder provided on the valve needle.
- the valve device 30 further comprises a plurality of reed valve elements 32 extending outwardly from the annular ring 31, each of which is arranged to cover a respective one of the orifices 21.
- Each reed valve element 32 is biased towards a closed position in which it covers its respective orifice 21, but is arranged to move away from its respective orifice when the difference between the fuel pressure in the upstream portion of the bore (above the restrictive element 20 in the orientation shown) and the fuel pressure in the downstream portion of the bore (below the restrictive element 20 in the orientation shown) is sufficient to overcome the pre-load of the reed valve elements 32, thereby opening the orifices 21 to allow fuel to flow, in use, through the orifices.
- the reed valve elements 32 When the reed valve elements 32 have moved away from the orifices 21 they do not provide a significant further restriction to the flow of fuel through the orifices. However, when the reed valve elements 32 are in their closed positions, they act to further restrict the flow of fuel through the orifices 21.
- each reed valve element 32 is provided with an aperture 33 at a position corresponding to its respective orifice 21.
- the apertures 33 of the reed valve elements 32 have significantly smaller cross-sectional areas than those of the orifices 21 in the restrictive element 20 in order to ensure that the flow of fuel is further restricted when the reed valve elements 32 are in their closed positions.
- the dimensions of the apertures 33 may be selected in order to tune the degree of further restriction for a desired operating characteristic of the fuel injector 100.
- Movement of the valve needle 1 is controlled by varying the fuel pressure in a control chamber 13 located at a proximal end of the valve needle.
- fuel pressure within the control chamber 13 is controlled by means of an actuation system (not shown) including a three-way valve which is controlled by, for example, a solenoid actuator or a piezoelectric actuator.
- the three-way valve is operable to supply high pressure fuel from the supply line without any connection to a low pressure drain in order to generate a high pressure within the control chamber 13, and to connect the control chamber 13 to the low pressure drain without any connection to the supply line in order to reduce the pressure within the control chamber.
- the tip 7 of the valve needle 1 is held in engagement with the nozzle seat 6 under the action of the spring 9 and high fuel pressure within the control chamber 13, as shown in Fig 3a . At this point no fuel is flowing through the bore 2 or out of the outlets 8, and the fuel pressure in the upstream portion of the bore is equal to the fuel pressure in the downstream portion of the bore.
- the three-way valve is operated to reduce the fuel pressure in the control chamber 13.
- the downward force applied to the top of the valve needle 1 is reduced.
- the valve needle moves away from the nozzle seat 6, as shown in Figure 3b .
- fuel is permitted to flow out of the downstream portion of the bore via the outlets 8.
- the restrictive element 20 moves upwardly together with the valve needle 1
- the fuel pressure in the downstream portion of the bore falls below the fuel pressure in the upstream portion of the bore (which is maintained at supply pressure through the supply line 5).
- This causes the reed valve elements 32 to move away from their respective orifices, thereby permitting fuel to flow through the orifices 21 from the upstream portion of the bore to the downstream portion of the bore.
- the restrictive element 20 due to the restriction provided by the restrictive element 20, the fuel pressure in the downstream portion of the bore remains lower than the fuel pressure in the upstream portion of the bore.
- the restrictive element 20 Since the pressure exerted on the upper surface 20a of the restrictive element 20 is higher than the pressure exerted on the lower surface 20b of the restrictive element 20, the restrictive element 20 imparts a net downward force to the valve needle 1 and so generally acts to decrease the speed at which the valve needle moves away from the nozzle seat 6, thereby reducing the velocity of the valve needle as it reaches its point of maximum lift.
- the three-way valve is operated to increase the fuel pressure in the control chamber 13.
- the downward force applied to the top of the valve needle 1 is increased.
- the valve needle 1 starts to move downwardly back towards the nozzle seat 6, as shown in Fig. 3c .
- fuel continues to flow out of the downstream portion of the bore via the outlets 8, and to be supplied into the upstream portion of the bore from the supply line.
- the fuel pressure in the upstream portion of the bore remains higher than the fuel pressure in the downstream portion of the bore, and the reed valve elements 32 remain open allowing fuel to flow through the orifices 21, as shown in Figure 3c . Since the pressure exerted on the upper surface 20a of the restrictive element 20 is higher than the pressure exerted on the lower surface 20b of the restrictive element 20, the restrictive element 20 imparts a net downward force on the valve needle 1 and so generally acts to increase the speed at which the valve needle moves towards the nozzle seat 6, thereby increasing the rate at which the fuel injector 100 may be closed.
- valve needle 1 As the valve needle 1 continues to move towards its closed position, the difference in fuel pressure between the upstream and downstream portions of the bore 2 is reduced due to the piston-like action of the restrictive element 20 on the fuel in the downstream portion of the bore 2 and a reduction in the rate at which fuel is dispensed from the downstream portion of the bore as the tip 7 of the valve needle 1 approaches the nozzle seat 6.
- the reed valve elements 32 Once the difference in fuel pressure has decreased to a sufficiently low level, the reed valve elements 32 move into their closed positions, as shown in Figure 3d , thereby further restricting the flow of fuel through the orifices 21.
- the fuel pressure in the downstream portion of the bore 2 becomes greater than the fuel pressure in the upstream portion of the bore 2.
- the pressure exerted on the lower surface 20b of the restrictive element 20 becomes greater than the pressure exerted on the upper surface 20a of the restrictive element 20, and so at this stage the restrictive element 20 imparts a net upward force on the valve needle 1 to damp the closing movement of the valve needle, thereby reducing the impact force of the valve needle 1 against the nozzle seat and minimising wear of the valve needle tip 7 and the nozzle seat 6.
- valve device 30 acts to generate a higher pressure difference between the fuel in the downstream portion of the bore and the fuel in the upstream portion of the bore, thereby increasing the damping effect during the final phase of closing movement.
- valve device 30 comprises multiple reed valve elements 32 projecting outwardly from an annular ring 31, each reed valve element being arranged to cover an individual orifice 21 in the restrictive element 20 in order to further restrict the flow of fuel through the orifice 21 when in its closed position.
- Figure 7 illustrates a valve device 130 for use in another embodiment of the present invention comprising a plurality of reed valve elements 132 projecting inwardly from an annular ring 131 which may be spot welded to a restrictive element 21 on the valve needle 1.
- valve device 30 may not comprise separate valve elements for each of the orifices, but may instead comprise one or more valve elements each arranged to cover multiple orifices.
- valve device 130 may not comprise reed valve elements 32, but may instead include one or more valves of a different type.
- FIGs 8 to 10 illustrate an alternative valve device 230 comprising an annular valve element 232 arranged to cover each of the orifices 21 in order to further restrict the flow of fuel through the orifices when in its closed position, the annular valve element being 232 biased towards its closed position by a disc spring 234 retained against a shoulder provided on the valve needle.
- Other valve devices are also possible.
- each of the orifices 21 extending through the restrictive element 20 is arranged to be covered by a valve element 32 when the valve elements are in their closed positions.
- the restrictive element 20 may additionally include one or more further orifices that are not covered by any valve element.
- each valve element 32 that covers an orifice 21 comprises an aperture 33 for allowing some fuel flow through the orifices 21 when the valve elements are in their closed positions (albeit at a further restricted rate).
- one or more valve elements covering one or more orifices may not comprise any aperture, in which case the valve elements may further restrict the flow of fuel through the orifices by completely preventing fuel flow through the orifices when in their closed positions. (In this case a small flow of fuel may still be permitted between the outer edge of the restrictive element 20 and the bore 2.)
- the restrictions provided by the restrictive element 20 take the form of orifices extending through the thickness of the restrictive element.
- one or more restrictions may instead be provided by one or more grooves provided in the outer surface of the restrictive element 20, the restrictions being provided between the grooves and the bore of the nozzle body.
- Such restrictions may be covered by any of the valve devices described above if modified to extend up to the outer edge of the restrictive element.
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Fuel-Injection Apparatus (AREA)
Abstract
Description
- The present invention relates to a fuel injector for use in delivering high pressure fuel to an internal combustion engine. In particular, but not exclusively, the invention relates to a fuel injector for use in a compression ignition internal combustion engine.
- In a direct acting injector, an actuator is coupled directly to the valve needle to control needle movement. Both piezoelectric and electromagnetic direct acting injectors are known. In an electromagnetic direct acting injector, a solenoid-operated actuator controls movement of a plunger by applying a current through a solenoid. The plunger acts on a chamber of fuel arranged at the upper end of a valve needle so that, through a hydraulic amplifier, the force of the plunger is transmitted to the valve needle. By varying the force applied to the valve needle, movement of the valve needle towards and away from a valve needle seat is controlled. In an indirect injector, valve needle movement is controlled differently, through an intermediate servo-valve which is operated by the actuator.
- In both types of injector the seat for the valve needle is typically defined by a frustoconical surface at the end of a bore provided in a nozzle body. When the valve needle is lifted away from the seat fuel is delivered through injector outlets into the combustion chamber, and when the valve needle is closed against the seat fuel injection is terminated.
- One problem in fuel injectors of this type is that the seat for the valve needle is prone to wear due to the repeated closing of the valve needle at the end of injection. In modern fuel injectors, there is an increasing trend towards smaller seat diameters so that wear issues are becoming even more prevalent and significant. Known solutions to improve on this problem include improving the material properties used at the seat, and using special heat treatments and coatings. However, these processes can be costly and still do not solve the problem fully.
- It is an object of the invention to provide a fuel injector which addresses the shortcomings of the prior art.
- An aspect of the invention provides a fuel injector for use in an internal combustion engine, the fuel injector comprising a nozzle body having a bore for receiving fuel from a supply line for pressurised fuel, an outlet from the bore for delivering fuel to the combustion cylinder, in use, a valve needle slidable within the bore between a closed position in which fuel flow through the outlet into the combustion chamber is prevented, and an open position in which fuel flow through the outlet into the combustion chamber is enabled, wherein the valve needle carries a restrictive element providing at least one restriction for restricting the flow of fuel through the bore such that, during opening movement of the valve needle, fuel pressure downstream of the restrictive element is less than a pressure of fuel supplied to the bore from the supply line; and at least one valve device which is operable in response to a pressure difference across the restrictive element so as to allow a flow of fuel through the at least one restriction during opening movement of the valve needle but to further restrict the flow of fuel through the at least one restriction during a final phase of closing movement of the valve needle, thereby to damp said final phase of closing movement as the valve needle is seated.
- By restricting the flow of fuel through the bore such that, during opening movement of the valve needle, fuel pressure downstream of the restrictive element is less than a pressure of fuel supplied to the bore from the supply line, the restrictive element acts to impart a net downward force to the valve needle during opening movement of the valve needle to thereby control the speed at which the valve needle moves towards its point of maximum lift. However, by further restricting the flow of fuel through the at least one restriction during a final phase of closing movement (when fuel would otherwise flow in reverse through the at least one restriction from the portion of the bore downstream of the restrictive element to the portion of the bore upstream of the restrictive element), the at least one valve device enables a higher pressure to be maintained in the portion of the bore downstream of the restrictive element than would be possible without the at least one valve device, thereby enabling the restrictive element to impart a greater net upward force to the valve needle than would be possible without the at least one valve device in order to provide a greater damping effect, thereby reducing the impact force of the valve needle against the nozzle seat and minimising wear of the valve needle tip and the nozzle seat.
- The final phase of closing movement (when fuel would otherwise flow in reverse through the at least one restriction from the portion of the bore downstream of the restrictive element to the portion of the bore upstream of the restrictive element), is typically the very end of closing movement of the valve needle, just before the valve needle is seated. For example, the at least one valve device may be arranged to further restrict the flow of fuel through the at least one restriction during the final phase of closing movement of the valve needle which may be over approximately the final 30%, or over approximately the final 20%, or over approximately the final 10% of the valve needle's travel towards the closed position, in normal use of the fuel injector. This final phase of closing movement may be considered to be the very end of closing movement, just before the valve needle is seated, and during which phase, without the presence of the valve device(s), fuel would otherwise flow in reverse through the at least one restriction from the portion of the bore downstream of the restrictive element to the portion of the bore upstream of the restrictive element. This is, typically, for example, over approximately the final 20% or so (e.g. between about the final 17% and about the final 23%) of closing movement of the valve needle (i.e. until it seats).
- The at least one valve device may not act to further restrict the flow of fuel through the at least one restriction (or may only further restrict the flow of fuel to a lesser extent) prior to approximately the final 30% (or approximately the final 20%, or approximately the final 10%) of the valve needle's travel towards the closed position, in normal use of the fuel injector. In this case the at least one valve device may not act to significantly reduce the closing speed of the valve needle until approximately the final 30% (or approximately the final 20%, or approximately the final 10%) of the valve needle's travel towards the closed position.
- The fuel injector may be a diesel injector or a gasoline injector.
- The at least one valve device may be located downstream of the restrictions provided by the restrictive element.
- The at least one valve device may comprise at least one valve element that is arranged to cover at least one of the restrictions when in a closed position to further restrict the flow of fuel through the at least one restriction.
- The at least one valve element may comprise at least one aperture for allowing a further restricted fuel flow through the at least one restriction when in the closed position. The dimensions of the aperture(s) may be selected in order to tune the degree of further restriction for a desired operating characteristic of the fuel injector.
- The at least one valve element may be arranged to further restrict the flow of fuel through the at least one restriction by completely preventing fuel flow through the at least one restriction when in its closed position. In this case no aperture as described above is present in the valve element.
- The at least one valve element may comprise at least one reed valve element.
- The at least one valve element may extend either radially inwardly or radially outwardly from an annular ring.
- The annular ring may be attached to the restrictive element and/or to the valve needle, for example by an adhesive or spot weld(s).
- Alternatively the valve element(s) may be attached to the restrictive element and/or to the valve needle individually, for example by an adhesive or spot weld(s).
- The at least one valve element may comprise an annular disc that is biased towards the restrictive element.
- The annular disc may be biased towards the restrictive device by a spring.
- The spring may be retained by a shoulder provided on the valve needle.
- The restrictive element is preferably fixed with respect to the valve needle. For example, the restrictive element may comprise an annular collar attached to or integrally formed with the valve needle. In other embodiments, a degree of relative movement between the valve needle and the restrictive element may be possible e.g. so that the restrictive element is 'floating'.
- The at least one restriction may take the form of at least one orifice extending through the thickness of the restrictive element and/or at least one groove provided in an outer surface of the restrictive element.
- Typically, the area of the orifice in the restrictive element may be around 7 times greater than the area of the fuel injector outlet(s), and may be around 30 times smaller than the area of the bore. These values are not intended to be limiting, but are given just to illustrate one possible example.
- The combined cross-sectional area of the aperture(s) may be significantly less than 50% of the combined cross sectional area of the restriction(s) and/or significantly less than 25% of the combined cross-sectional area of the outlet(s). Other values are also possible. It will be appreciated that the relative dimensions of the bore, the restrictive element, the restriction(s), the aperture(s) and the outlet(s) may be varied in order to select the desired damping performance.
- Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any aspect or embodiment can be combined in any way and/or combination with those in other aspects and/or embodiments, unless such features are incompatible.
- In order that the present invention may be more readily understood, an example of the invention will now be described in detail with reference to the accompanying figures, in which:
-
Figure 1 illustrates a fuel injector according to one possible embodiment of the present invention; -
Figure 2 illustrates a restrictive element of a valve needle of the fuel injector ofFigure 1 ; -
Figures 3a to 3d schematically illustrate various stages during the operation of the fuel injector ofFigure 1 ; -
Figures 4 to 6 illustrate a valve device associated with the restrictive element of the valve needle of the fuel injector ofFigure 1 ; -
Figure 7 illustrates an alternative valve device; and -
Figures 8 to 10 illustrate a further alternative valve device. - For the purpose of the following description it will be appreciated that references to upper, lower, upward, downward, above and below, for example, are not intended to be limiting and relate only to the orientation of the injector as shown in the illustration.
- The present invention relates to a
fuel injector 100 of the type generally shown inFigure 1 . Thefuel injector 100 is suitable for use in a fuel injection system of an internal combustion engine, and particularly a diesel engine in which fuel is typically injected into the engine at high pressure levels in excess of 2000 bar, and commonly as high as 3000 bar. - The
fuel injector 100 comprises avalve needle 1 that is slidable within abore 2 of anozzle body 3. A proximal end of thenozzle body 3 is coupled to apiston guide 4. The proximal end of the bore receives high pressure fuel, in use, from asupply line 5 provided in the piston guide. The bore includes a section of comparativelysmall diameter 2a towards its distal end and a section of comparativelylarge diameter 2b towards its proximal end. - The
bore 2, at its distal end, defines anozzle seat 6 of generally frusto-conical form with which atip 7 of thevalve needle 1 is engageable. Downstream of thenozzle seat 6, the nozzle body is provided with a plurality ofoutlets 8 for delivering fuel to a combustion cylinder, in use. When thevalve needle 1 is in its closed position, thetip 7 of the valve needle is engaged with thenozzle seat 6 to prevent fuel from being delivered from thebore 2 through theoutlets 8. However, when thevalve needle 1 is lifted away from thenozzle seat 6, as described below, thetip 7 of thevalve needle 1 moves out of engagement with thenozzle seat 6 to allow fuel to be delivered from thebore 2 through theoutlets 8. Aspring 9 is provided towards a proximal end of thevalve needle 1, which acts to urge thevalve needle 1 towards its closed position. - The
valve needle 1 comprises avalve needle guide 10 towards its distal end. Thevalve needle guide 10 slidingly engages thebore 2 in the section of comparativelysmall diameter 2a to prevent lateral movement of thevalve needle 1 within the bore. Thevalve needle guide 10 includes a plurality of grooves to permit the passage of fuel past the valve needle guide. Thevalve needle 1 also comprises aproximal guide portion 11 at is proximal end that slidingly engages thepiston guide 4 to prevent lateral movement of thevalve needle 1 within thebore 2. - The
valve needle 1 is provided with a plurality of thrust surfaces 12 of generally frustoconical form that are exposed to fuel pressure within thebore 2 in order to provide an upward force to urge thevalve needle 1 away from its closed position. - The
valve needle 1 is further provided with a restrictive element 20 (shown more clearly inFig. 2 ) in the form of an annular collar extending around the valve needle and located within thebore 2 in the section of comparativelylarge diameter 2b. Therestrictive element 20 is fixed with respect to the valve needle, and may be integrally formed with thevalve needle 1, or alternatively may be a separate component that is attached to the valve needle (for example by press fitting). The restrictive element is arranged to move together with the valve needle as the valve needle slides within thebore 2. Therestrictive element 20 has a diameter that is slightly smaller than that of thebore 2 at the section of comparativelylarge diameter 2b and so extends almost up the side-wall of the bore. Therestrictive element 20 divides thebore 2 into a portion located upstream of the restrictive element (the upstream portion) and a portion located downstream of the restrictive element (the downstream portion). Therestrictive element 20 comprises anupper surface 20a facing towards the proximal end of the bore, and alower surface 20b facing towards the distal end of the bore. Therestrictive element 20 acts to restrict the flow of fuel through thebore 2 such that the fuel pressure downstream of the restriction is generally less than a pressure of fuel supplied to thebore 2 from thesupply line 5 during opening movement of the valve needle, as described below. - The
restrictive element 20 is provided with a plurality of passages ororifices 21 extending through its thickness to allow the restricted flow of fuel through therestrictive element 20 and through thebore 2. Theorifices 21 act as a plurality of restrictions because the combined cross-sectional area of the orifices is significantly smaller than the cross-sectional area of thebore 2. Theorifices 21 are spaced around therestrictive element 20 in a circle. However, it will be appreciated that the number and spatial arrangement of theorifices 21 is not critical, and that in other embodiments there may only be one orifice. - The
restrictive element 20 is provided with a valve device 30 (not shown inFigure 1 but illustrated inFigures 4 to 6 ). Thevalve device 30 comprises anannular ring 31 that surrounds thevalve needle 1 and is spot welded to the valve needle and/or to the lower surface of the restrictive element and/or held between therestrictive element 20 and a shoulder provided on the valve needle. Thevalve device 30 further comprises a plurality ofreed valve elements 32 extending outwardly from theannular ring 31, each of which is arranged to cover a respective one of theorifices 21. - Each
reed valve element 32 is biased towards a closed position in which it covers itsrespective orifice 21, but is arranged to move away from its respective orifice when the difference between the fuel pressure in the upstream portion of the bore (above therestrictive element 20 in the orientation shown) and the fuel pressure in the downstream portion of the bore (below therestrictive element 20 in the orientation shown) is sufficient to overcome the pre-load of thereed valve elements 32, thereby opening theorifices 21 to allow fuel to flow, in use, through the orifices. When thereed valve elements 32 have moved away from theorifices 21 they do not provide a significant further restriction to the flow of fuel through the orifices. However, when thereed valve elements 32 are in their closed positions, they act to further restrict the flow of fuel through theorifices 21. - In order to allow some fuel flow through the
orifices 21 when thereed valve elements 32 are in their closed positions (albeit at a further restricted rate), eachreed valve element 32 is provided with anaperture 33 at a position corresponding to itsrespective orifice 21. Theapertures 33 of thereed valve elements 32 have significantly smaller cross-sectional areas than those of theorifices 21 in therestrictive element 20 in order to ensure that the flow of fuel is further restricted when thereed valve elements 32 are in their closed positions. The dimensions of theapertures 33 may be selected in order to tune the degree of further restriction for a desired operating characteristic of thefuel injector 100. Movement of thevalve needle 1 is controlled by varying the fuel pressure in acontrol chamber 13 located at a proximal end of the valve needle. In an indirect injector, fuel pressure within thecontrol chamber 13 is controlled by means of an actuation system (not shown) including a three-way valve which is controlled by, for example, a solenoid actuator or a piezoelectric actuator. The three-way valve is operable to supply high pressure fuel from the supply line without any connection to a low pressure drain in order to generate a high pressure within thecontrol chamber 13, and to connect thecontrol chamber 13 to the low pressure drain without any connection to the supply line in order to reduce the pressure within the control chamber. - Operation of the
fuel injector 100 will now be described with reference toFigures 3a to 3d , which provide a highly schematic representation of the fuel injector during various stages of operation. - Before the
fuel injector 100 is opened to commence delivery of fuel, thetip 7 of thevalve needle 1 is held in engagement with thenozzle seat 6 under the action of thespring 9 and high fuel pressure within thecontrol chamber 13, as shown inFig 3a . At this point no fuel is flowing through thebore 2 or out of theoutlets 8, and the fuel pressure in the upstream portion of the bore is equal to the fuel pressure in the downstream portion of the bore. - When it is desired to open the
fuel injector 100 to commence the delivery of fuel from theoutlets 8, the three-way valve is operated to reduce the fuel pressure in thecontrol chamber 13. As the fuel pressure in thecontrol chamber 13 is reduced, the downward force applied to the top of thevalve needle 1 is reduced. Once the upward force exerted on thevalve needle 1 by the thrust surfaces 12 is sufficient to overcome the downward force exerted by thespring 9 and other downward forces exerted by the fuel on other parts of the valve needle, the valve needle moves away from thenozzle seat 6, as shown inFigure 3b . When thevalve needle 1 moves away from thenozzle seat 6, fuel is permitted to flow out of the downstream portion of the bore via theoutlets 8. As fuel flows out from the downstream portion of the bore and therestrictive element 20 moves upwardly together with thevalve needle 1, the fuel pressure in the downstream portion of the bore falls below the fuel pressure in the upstream portion of the bore (which is maintained at supply pressure through the supply line 5). This causes thereed valve elements 32 to move away from their respective orifices, thereby permitting fuel to flow through theorifices 21 from the upstream portion of the bore to the downstream portion of the bore. However, due to the restriction provided by therestrictive element 20, the fuel pressure in the downstream portion of the bore remains lower than the fuel pressure in the upstream portion of the bore. Since the pressure exerted on theupper surface 20a of therestrictive element 20 is higher than the pressure exerted on thelower surface 20b of therestrictive element 20, therestrictive element 20 imparts a net downward force to thevalve needle 1 and so generally acts to decrease the speed at which the valve needle moves away from thenozzle seat 6, thereby reducing the velocity of the valve needle as it reaches its point of maximum lift. - When it is desired to close the
fuel injector 100, the three-way valve is operated to increase the fuel pressure in thecontrol chamber 13. As the fuel pressure in the control chamber increases, the downward force applied to the top of thevalve needle 1 is increased. Once the downward force exerted on thevalve needle 1 by the fuel in thecontrol chamber 13 in combination with other downward forces exerted by thespring 9 and by fuel in the bore (for example on theupper surface 20a of the restrictive element 20) is sufficient to overcome the upward forces exerted on thevalve needle 1 at the thrust surfaces andlower surface 20b of the restrictive element, thevalve needle 1 starts to move downwardly back towards thenozzle seat 6, as shown inFig. 3c . As this happens, fuel continues to flow out of the downstream portion of the bore via theoutlets 8, and to be supplied into the upstream portion of the bore from the supply line. - During the first part of the closing movement of the
valve needle 1, the fuel pressure in the upstream portion of the bore remains higher than the fuel pressure in the downstream portion of the bore, and thereed valve elements 32 remain open allowing fuel to flow through theorifices 21, as shown inFigure 3c . Since the pressure exerted on theupper surface 20a of therestrictive element 20 is higher than the pressure exerted on thelower surface 20b of therestrictive element 20, therestrictive element 20 imparts a net downward force on thevalve needle 1 and so generally acts to increase the speed at which the valve needle moves towards thenozzle seat 6, thereby increasing the rate at which thefuel injector 100 may be closed. - As the
valve needle 1 continues to move towards its closed position, the difference in fuel pressure between the upstream and downstream portions of thebore 2 is reduced due to the piston-like action of therestrictive element 20 on the fuel in the downstream portion of thebore 2 and a reduction in the rate at which fuel is dispensed from the downstream portion of the bore as thetip 7 of thevalve needle 1 approaches thenozzle seat 6. Once the difference in fuel pressure has decreased to a sufficiently low level, thereed valve elements 32 move into their closed positions, as shown inFigure 3d , thereby further restricting the flow of fuel through theorifices 21. During a final phase of closing movement of the valve needle, and at the very end of the closing movement of thevalve needle 1, the fuel pressure in the downstream portion of thebore 2 becomes greater than the fuel pressure in the upstream portion of thebore 2. Once the fuel pressure in the downstream portion of the bore exceeds the fuel pressure in the upstream portion of thebore 2, the pressure exerted on thelower surface 20b of therestrictive element 20 becomes greater than the pressure exerted on theupper surface 20a of therestrictive element 20, and so at this stage therestrictive element 20 imparts a net upward force on thevalve needle 1 to damp the closing movement of the valve needle, thereby reducing the impact force of thevalve needle 1 against the nozzle seat and minimising wear of thevalve needle tip 7 and thenozzle seat 6. At this point, the further restriction provided by thereed valve elements 32 reduces the rate at which fuel can flow in reverse through theorifices 21 from the downstream portion of the bore back into the upstream portion of the bore. In this way thevalve device 30 acts to generate a higher pressure difference between the fuel in the downstream portion of the bore and the fuel in the upstream portion of the bore, thereby increasing the damping effect during the final phase of closing movement. - In the above-described embodiment, the
valve device 30 comprises multiplereed valve elements 32 projecting outwardly from anannular ring 31, each reed valve element being arranged to cover anindividual orifice 21 in therestrictive element 20 in order to further restrict the flow of fuel through theorifice 21 when in its closed position. However, many other valve devices are possible within the scope of the present invention. For example,Figure 7 illustrates avalve device 130 for use in another embodiment of the present invention comprising a plurality ofreed valve elements 132 projecting inwardly from anannular ring 131 which may be spot welded to arestrictive element 21 on thevalve needle 1. In other embodiments, thevalve device 30 may not comprise separate valve elements for each of the orifices, but may instead comprise one or more valve elements each arranged to cover multiple orifices. In other embodiments, thevalve device 130 may not comprisereed valve elements 32, but may instead include one or more valves of a different type. - By way of example,
Figures 8 to 10 illustrate an alternative valve device 230 comprising anannular valve element 232 arranged to cover each of theorifices 21 in order to further restrict the flow of fuel through the orifices when in its closed position, the annular valve element being 232 biased towards its closed position by adisc spring 234 retained against a shoulder provided on the valve needle. Other valve devices are also possible. - In the above-described embodiment, each of the
orifices 21 extending through therestrictive element 20 is arranged to be covered by avalve element 32 when the valve elements are in their closed positions. However, in other embodiments therestrictive element 20 may additionally include one or more further orifices that are not covered by any valve element. - In the above-described embodiment, each
valve element 32 that covers anorifice 21 comprises anaperture 33 for allowing some fuel flow through theorifices 21 when the valve elements are in their closed positions (albeit at a further restricted rate). However, in other embodiments, one or more valve elements covering one or more orifices may not comprise any aperture, in which case the valve elements may further restrict the flow of fuel through the orifices by completely preventing fuel flow through the orifices when in their closed positions. (In this case a small flow of fuel may still be permitted between the outer edge of therestrictive element 20 and thebore 2.) - In the above-described embodiment, the restrictions provided by the
restrictive element 20 take the form of orifices extending through the thickness of the restrictive element. However, in other embodiments one or more restrictions may instead be provided by one or more grooves provided in the outer surface of therestrictive element 20, the restrictions being provided between the grooves and the bore of the nozzle body. Such restrictions may be covered by any of the valve devices described above if modified to extend up to the outer edge of the restrictive element.
Claims (15)
- A fuel injector (100) for use in an internal combustion engine, the fuel injector comprising:a nozzle body (3) having a bore (2) for receiving fuel from a supply line (5) for pressurised fuel,an outlet (8) from the bore (2) for delivering fuel to the combustion cylinder, in use,a valve needle (1) slidable within the bore (2) between a closed position in which fuel flow through the outlet (8) into the combustion chamber is prevented, and an open position in which fuel flow through the outlet (8) into the combustion chamber is enabled, wherein the valve needle (100) carries a restrictive element (20) providing at least one restriction (21) for restricting the flow of fuel through the bore (2) such that, during opening movement of the valve needle (1), fuel pressure downstream of the restrictive element (20) is less than a pressure of fuel supplied to the bore (2) from the supply line (5); andat least one valve device (30) which is operable in response to a pressure difference across the restrictive element (20) so as to allow a flow of fuel through the at least one restriction (21) during opening movement of the valve needle (1) but to further restrict the flow of fuel through the at least one restriction (21) during a final phase of closing movement of the valve needle (1), thereby to damp said final phase of closing movement as the valve needle is seated.
- A fuel injector (100) according to claim 1, wherein the at least one valve device (30) is arranged to further restrict the flow of fuel through the at least one restriction (21) during the final phase of closing movement which is approximately the final 30%, or approximately the final 20%, or approximately the final 10%, of the valve needle travel towards the closed position in normal use of the fuel injector.
- A fuel injector (100) according to claim 1 or claim 2, wherein the at least one valve device (30) is located downstream of the at least one restriction (21) provided by the restrictive element (20).
- A fuel injector (100) according to any of claims 1 to 3, wherein the at least one valve device (30) comprises at least one valve element (32) that is arranged to cover at least one of the restrictions (21) when in a closed position to further restrict the flow of fuel through the at least one restriction (21).
- A fuel injector (100) according to claim 4, wherein the at least one valve element (32) comprises at least one aperture (33) for allowing a further restricted fuel flow through the at least one restriction (21) when in the closed position.
- A fuel injector (100) according to claim 4, wherein the at least one valve element (32) is arranged to further restrict the flow of fuel through the at least one restriction (21) by completely preventing fuel flow through the at least one restriction (21) when in its closed position.
- A fuel injector (100) according to any of claims 4 to 6, wherein the at least one valve element (32) comprises at least one reed valve element.
- A fuel injector (100) according to any of claims 4 to 7, wherein the at least one valve element (32) extends either radially inwardly or radially outwardly from an annular ring (31).
- A fuel injector (100) according to any claim 8, wherein the annular ring (31) is attached to the restrictive element (20) and/or to the valve needle (1).
- A fuel injector (100) according to any of claims 4 to 6, wherein the at least one valve element comprises an annular disc (232) that is biased towards the restrictive element.
- A fuel injector (100) according to claim 10, wherein the annular disc (232) is biased towards the restrictive device by a spring (234).
- A fuel injector (100) according to claim 11, wherein the spring (234) is retained by a shoulder provided on the valve needle.
- A fuel injector (100) according to any preceding claim, wherein the restrictive element (20) comprises an annular collar attached to or integrally formed with the valve needle (1).
- A fuel injector (100) according to any preceding claim, wherein the at least one restriction (21) takes the form of at least one orifice extending through the thickness of the restrictive element (20).
- A fuel injector (100) according to any preceding claim, wherein the at least one restriction (21) takes the form of at least one groove provided in an outer surface of the restrictive element (20) to define the restriction (21) together with the bore.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP18173371.8A EP3399177B1 (en) | 2016-03-16 | 2017-03-16 | Fuel injector |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB1604455.4A GB2548375A (en) | 2016-03-16 | 2016-03-16 | Fuel injector |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
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EP18173371.8A Division EP3399177B1 (en) | 2016-03-16 | 2017-03-16 | Fuel injector |
Publications (1)
Publication Number | Publication Date |
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EP3219974A1 true EP3219974A1 (en) | 2017-09-20 |
Family
ID=55952386
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
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EP18173371.8A Active EP3399177B1 (en) | 2016-03-16 | 2017-03-16 | Fuel injector |
EP17161355.7A Withdrawn EP3219974A1 (en) | 2016-03-16 | 2017-03-16 | Fuel injector |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
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EP18173371.8A Active EP3399177B1 (en) | 2016-03-16 | 2017-03-16 | Fuel injector |
Country Status (2)
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EP (2) | EP3399177B1 (en) |
GB (1) | GB2548375A (en) |
Families Citing this family (1)
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DK181318B1 (en) * | 2022-02-18 | 2023-08-10 | Man Energy Solutions Filial Af Man Energy Solutions Se Tyskland | A fuel valve for a large turbocharged two-stroke uniflow crosshead internal combustion engine |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6318646B1 (en) * | 1999-03-26 | 2001-11-20 | MAGNETI MARELLI S.p.A. | Fuel injector |
US6499467B1 (en) * | 2000-03-31 | 2002-12-31 | Cummins Inc. | Closed nozzle fuel injector with improved controllabilty |
EP1369579A1 (en) * | 2002-06-07 | 2003-12-10 | Magneti Marelli Powertrain S.p.A. | Fuel injector for an internal combustion engine with multihole atomizer |
EP1990532A1 (en) * | 2007-05-07 | 2008-11-12 | Robert Bosch GmbH | Fuel injector for a combustion engine with common rail injection system |
WO2013034543A1 (en) * | 2011-09-08 | 2013-03-14 | Delphi Technologies Holding S.À.R.L. | Injection nozzle |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE19960339A1 (en) * | 1999-12-15 | 2001-06-21 | Bosch Gmbh Robert | Fuel injector |
US7690588B2 (en) * | 2007-07-31 | 2010-04-06 | Caterpillar Inc. | Fuel injector nozzle with flow restricting device |
GB201322485D0 (en) * | 2013-12-19 | 2014-02-05 | Delphi Tech Holding Sarl | Fuel injection nozzle |
US9822748B2 (en) * | 2014-05-31 | 2017-11-21 | Cummins Inc. | Restrictive flow passage in common rail injectors |
-
2016
- 2016-03-16 GB GB1604455.4A patent/GB2548375A/en not_active Withdrawn
-
2017
- 2017-03-16 EP EP18173371.8A patent/EP3399177B1/en active Active
- 2017-03-16 EP EP17161355.7A patent/EP3219974A1/en not_active Withdrawn
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6318646B1 (en) * | 1999-03-26 | 2001-11-20 | MAGNETI MARELLI S.p.A. | Fuel injector |
US6499467B1 (en) * | 2000-03-31 | 2002-12-31 | Cummins Inc. | Closed nozzle fuel injector with improved controllabilty |
EP1369579A1 (en) * | 2002-06-07 | 2003-12-10 | Magneti Marelli Powertrain S.p.A. | Fuel injector for an internal combustion engine with multihole atomizer |
EP1990532A1 (en) * | 2007-05-07 | 2008-11-12 | Robert Bosch GmbH | Fuel injector for a combustion engine with common rail injection system |
WO2013034543A1 (en) * | 2011-09-08 | 2013-03-14 | Delphi Technologies Holding S.À.R.L. | Injection nozzle |
Also Published As
Publication number | Publication date |
---|---|
GB201604455D0 (en) | 2016-04-27 |
EP3399177A1 (en) | 2018-11-07 |
GB2548375A (en) | 2017-09-20 |
EP3399177B1 (en) | 2020-01-08 |
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