EP1391610A1 - Valve needle and metering device comprising the same - Google Patents
Valve needle and metering device comprising the same Download PDFInfo
- Publication number
- EP1391610A1 EP1391610A1 EP02018664A EP02018664A EP1391610A1 EP 1391610 A1 EP1391610 A1 EP 1391610A1 EP 02018664 A EP02018664 A EP 02018664A EP 02018664 A EP02018664 A EP 02018664A EP 1391610 A1 EP1391610 A1 EP 1391610A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- valve
- needle
- guide element
- valve needle
- fuel
- 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- Withdrawn
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Classifications
-
- 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
-
- 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
Definitions
- the present invention relates to a valve needle for a high-pressure fuel injector, in which axial movement of the valve needle in a valve seat controls opening and closing of a metering opening of the injector, comprising a needle body with a cylindrical upper portion, the needle body having an end part provided with a plunger for closing the metering opening.
- the present invention further relates to a metering device for dosing pressurized fluids, particularly an injection valve for a fuel injection system in an internal combustion engine, comprising such a valve needle.
- the fit between the valve needle and its seat presents onerous geometrical and manufacturing requirements. These requirements relate, for example, to the clearances of the sliding motion of the needle in the seat, the coaxial arrangement of the guide elements formed on the injector needle and their seats, and to the cylindrical shape and roughness that must be achieved for the components to function properly.
- the valve needle is provided with a lower guide element and an upper guide element. Both of these elements have the function to precisely guide the sliding movement of the valve needle in its seat.
- the upper guide element has further the function to dampen the pressure peaks arising from the opening and closing action of the valve needle, heading upstream to the dynamic sealing area. If not damped, these pressure peaks may damage or even break the bellows separating the fuel space from an actuator chamber at lower pressure. In view of the compact dimensions and the high precision requirements, the manufacturing of such an injector needle is complicated and expensive.
- valve needle of the above mentioned type which is easier and more economic to manufacture. Especially, this object should be attained while the needle is still precisely guided in its seat and no excessive pressure peaks propagate upstream to the bellows area.
- valve needle with the features of appended claim 1.
- Advantageous embodiments of the invention are disclosed in the dependent claims 2 to 5.
- the invention also contains a metering device for dosing pressurized fluids comprising such a valve needle according to independent claim 6.
- the valve needle with the features of the preamble of claim 1 has a single guide element surrounding the needle body, the guide element providing a close sliding fit of the valve needle in the valve seat.
- the invention is thus based on the idea to replace the two guide elements of current designs by a single guide element.
- This makes it possible to arrange the guide element in a higher position thereby increasing the volume of the fuel accumulation chamber located immediately upstream of the plunger of the valve.
- upstream of the guide element at the upper end of the needle body there is more space available on the seat of the needle, to accommodate the fuel admission holes.
- This characteristic not only facilitates stabilization of the flow in the region of the valve body but also simplifies the associated machining, such as the burr removal.
- the guide element has a polygonal cross section to ensure a precise sliding fit of the valve needle relative to the outer seat and to transfer the fuel under pressure directly into the combustion chamber.
- a peripheral recess is preferably formed between the single guide element and the plunger to provide a fuel accumulation chamber between the valve needle and the valve seat, wherein the axial extension of the peripheral recess is in the range of 1.6 to 2.5 times the diameter d of the cylindrical portion of the needle body.
- a large fuel accumulation chamber may thus be formed.
- the guide element has an axial extension in the range of 4.0 to 5.0 times the diameter d of the cylindrical portion of the needle body to form an elongated single guide element.
- a metering device for dosing pressurized fluids particularly an injection valve for a fuel injection system in an internal combustion engine, comprises a housing having an end part provided with fuel admission holes leading to an outlet passage terminating with a metering opening, the lower part of the housing forming a valve seat surrounding the outlet passage.
- Figure 1 illustrates a valve needle 10 for a high-pressure fuel injector according to a specific embodiment of the invention.
- the needle body 12 of the needle 10 comprises a top portion 18 for making contact with a piezoelectric actuator assembly (not shown), a cylindrical upper portion 14, a portion containing the single guide element 16, a recessed portion 18 and a plunger 20.
- the needle 10 slides in the outlet passage 30 of the injector which terminates in a metering opening 36.
- the outlet passage 30 is surrounded by the seat 40 of the valve needle. Pressurized fuel to be injected in an engine cylinder enters the outlet passage 30 via the fuel admission holes 42.
- the guide element 16 may have a polygonal cross section with four flat surfaces 161 separated by rounded portions 163 that provide the close sliding fit of the valve needle 10.
- the single guide element 16 is arranged in a higher position compared to conventional designs with two guide elements. Thereby, the volume of the fuel accumulation chamber 34 located immediately upstream of the plunger 20 of the valve can be increased.
- Figure 3 shows an alternative shape of the cross section of the guide element 16, with three flat surfaces 161 separated by rounded portions 163. Again, the rounded portion 163 provide a close sliding fit of the valve needle 10.
Abstract
The invention relates to a valve needle for a high-pressure
injector for a fuel injection system, in which axial movement
of the valve needle in a valve seat controls opening and
closing a metering opening of the injector, comprising an
needle body (12) with a cylindrical upper portion (14), the
needle body (12) having an end part provided with a plunger
(20) for closing the metering opening (36). According to the
invention a single guide element (16) is provided, surrounding
the needle body, the guide element (16) providing a close
sliding fit of the valve needle (10) in the valve seat (40).
Description
The present invention relates to a valve needle for a high-pressure
fuel injector, in which axial movement of the valve
needle in a valve seat controls opening and closing of a metering
opening of the injector, comprising a needle body with
a cylindrical upper portion, the needle body having an end
part provided with a plunger for closing the metering opening.
The present invention further relates to a metering device
for dosing pressurized fluids, particularly an injection
valve for a fuel injection system in an internal combustion
engine, comprising such a valve needle.
In the production of injection valves for high-pressure direct-injection
gasoline engines controlled by a piezoelectric
actuator, the fit between the valve needle and its seat presents
onerous geometrical and manufacturing requirements.
These requirements relate, for example, to the clearances of
the sliding motion of the needle in the seat, the coaxial arrangement
of the guide elements formed on the injector needle
and their seats, and to the cylindrical shape and roughness
that must be achieved for the components to function properly.
In current designs, the valve needle is provided with a lower
guide element and an upper guide element. Both of these elements
have the function to precisely guide the sliding movement
of the valve needle in its seat. The upper guide element
has further the function to dampen the pressure peaks arising
from the opening and closing action of the valve needle,
heading upstream to the dynamic sealing area. If not damped,
these pressure peaks may damage or even break the bellows
separating the fuel space from an actuator chamber at lower
pressure. In view of the compact dimensions and the high precision
requirements, the manufacturing of such an injector
needle is complicated and expensive.
In view of the foregoing, it is an object of the present invention
to provide a valve needle of the above mentioned type
which is easier and more economic to manufacture. Especially,
this object should be attained while the needle is still precisely
guided in its seat and no excessive pressure peaks
propagate upstream to the bellows area.
The above object is achieved by the valve needle with the
features of appended claim 1. Advantageous embodiments of the
invention are disclosed in the dependent claims 2 to 5. The
invention also contains a metering device for dosing pressurized
fluids comprising such a valve needle according to independent
claim 6.
According to the invention, the valve needle with the features
of the preamble of claim 1 has a single guide element
surrounding the needle body, the guide element providing a
close sliding fit of the valve needle in the valve seat.
The invention is thus based on the idea to replace the two
guide elements of current designs by a single guide element.
This makes it possible to arrange the guide element in a
higher position thereby increasing the volume of the fuel accumulation
chamber located immediately upstream of the
plunger of the valve. Also, upstream of the guide element at
the upper end of the needle body, there is more space available
on the seat of the needle, to accommodate the fuel admission
holes. This characteristic not only facilitates stabilization
of the flow in the region of the valve body but
also simplifies the associated machining, such as the burr
removal.
In a preferred embodiment of the invention, the guide element
has a polygonal cross section to ensure a precise sliding fit
of the valve needle relative to the outer seat and to transfer
the fuel under pressure directly into the combustion
chamber.
It is further preferred that the guide element of the valve
needle according to the invention has four flat surfaces
separated by rounded portions that provide the close sliding
fit of the valve needle.
A peripheral recess is preferably formed between the single
guide element and the plunger to provide a fuel accumulation
chamber between the valve needle and the valve seat, wherein
the axial extension of the peripheral recess is in the range
of 1.6 to 2.5 times the diameter d of the cylindrical portion
of the needle body. A large fuel accumulation chamber may
thus be formed.
In a further preferred embodiment of the invention, the guide
element has an axial extension in the range of 4.0 to 5.0
times the diameter d of the cylindrical portion of the needle
body to form an elongated single guide element.
According to the invention, a metering device for dosing
pressurized fluids, particularly an injection valve for a
fuel injection system in an internal combustion engine, comprises
a housing having an end part provided with fuel admission
holes leading to an outlet passage terminating with a
metering opening, the lower part of the housing forming a
valve seat surrounding the outlet passage. It further comprises
an axially moveable valve needle of the type described
above, sliding in the valve seat and controlling opening and
closing of the metering opening by its axial movement, and a
piezoelectric actuator assembly in axial alignment with the
valve needle and cooperating with the valve needle to control
its axial movement, wherein a fuel accumulation chamber is
formed between the plunger, guide element and the valve seat,
and a upstream chamber for damping fuel pressure peaks is
formed between the guide element, the fuel admission holes
and the valve seat.
In addition to the advantages mentioned above, the technical
features of the invention
- facilitate the needle grinding process, because of the reduced total length to be ground (no upper guide),
- facilitate the upper side valve seat manufacturing process, because there is no necessity to grind the upper body and also there is no necessity to have an internal recess between an upper and lower guide,
- improve the damping of pressure peaks with the increased upstream chamber height,
- improve the robustness of the design to spray asymmetry issues, and
- provide the possibility to keep a tighter clearance of the guide element.
The invention, both its construction an its method of operation
together with additional objects and advantages thereof,
will best be understood from the following description of a
specific embodiment when read in connection with the accompanying
drawings, wherein
- Figure 1
- is a schematic axial cross section of a valve needle according to an embodiment of the invention in its seat;
- Figure 2
- is a cross section of the guide element of the needle, taken along the line II-II of Fig. 1; and
- Figure 3
- is an alternative cross section of the guide element of the needle, taken along the line II-II of Fig. 1.
Figure 1 illustrates a valve needle 10 for a high-pressure
fuel injector according to a specific embodiment of the invention.
From top to bottom in the view of Fig. 1, the needle
body 12 of the needle 10 comprises a top portion 18 for making
contact with a piezoelectric actuator assembly (not
shown), a cylindrical upper portion 14, a portion containing
the single guide element 16, a recessed portion 18 and a
plunger 20.
The needle 10 slides in the outlet passage 30 of the injector
which terminates in a metering opening 36. The outlet passage
30 is surrounded by the seat 40 of the valve needle. Pressurized
fuel to be injected in an engine cylinder enters the
outlet passage 30 via the fuel admission holes 42.
As best seen in Fig. 2, the guide element 16 may have a polygonal
cross section with four flat surfaces 161 separated
by rounded portions 163 that provide the close sliding fit of
the valve needle 10.
The single guide element 16 is arranged in a higher position
compared to conventional designs with two guide elements.
Thereby, the volume of the fuel accumulation chamber 34 located
immediately upstream of the plunger 20 of the valve can
be increased.
In the upper portion of the needle 10, on the other hand, as
compared with the conventional solution with two guide elements,
more space is available on the seat 40 of the needle
to accommodate the two radial fuel admission holes 42. This
facilitates the stabilization of the flow in the region of
the valve body 12 and simplifies the associated machining.
Figure 3 shows an alternative shape of the cross section of
the guide element 16, with three flat surfaces 161 separated
by rounded portions 163. Again, the rounded portion 163 provide
a close sliding fit of the valve needle 10.
The features disclosed in the foregoing description, in the
drawings, and in the claims may alone as well as in any possible
combination be important for the realization of the invention.
Claims (6)
- A Valve needle for a high-pressure fuel injector, in which axial movement of the valve needle in a valve seat controls opening and closing of a metering opening of the injector, comprising a needle body (12) with a cylindrical upper portion (14), the needle body (12) having an end part provided with a plunger (20) for closing the metering opening (36),
characterized by
a single guide element (16) surrounding the needle body, the guide element (16) providing a close sliding fit of the valve needle (10) in the valve seat (40). - The Valve needle according to claim 1,
characterized in that
the guide element (16) has a polygonal cross section. - The Valve needle according to claim 1 or 2,
characterized in that
the guide element (16) has two, three, or four flat surfaces (161) separated by rounded portions (163) that provide the close sliding fit of the valve needle (10). - The Valve needle according to any of the preceding claims, characterized in thata peripheral recess (18) is formed between the single guide element (16) and the plunger (20) to provide a fuel accumulation chamber (34) between the valve needle (10) and the valve seat (40),wherein the axial extension of the peripheral recess (14) is in the range of 1.6 to 2.5 times the diameter d of the cylindrical portion (14) of the needle body (12).
- The Valve needle according to any of the preceding claims,
characterized in that
the guide element (16) has an axial extension in the range of 4.0 to 5.0 times the diameter d of the cylindrical portion (14) of the needle body (12). - A Metering device for dosing pressurized fluids, particularly an injection valve for a fuel injection system in an internal combustion engine, comprisinga housing having an end part provided with fuel admission holes (42) leading to an outlet passage (30) terminating with a metering opening (36), the lower part of the housing forming a valve seat (40) surrounding the outlet passage (30),an axially moveable valve needle (10) according to any of the preceding claims, sliding in the valve seat (40) and controlling opening and closing of the metering opening (36) by its axial movement, anda piezoelectric actuator assembly in axial alignment with the valve needle (10) and cooperating with the valve needle (10) to control its axial movement,wherein a fuel accumulation chamber (34) is formed between the plunger (20), guide element (16) and the valve seat (40), and a upstream chamber (32) for damping fuel pressure peaks is formed between the guide element (16), the fuel admission holes (42) and the valve seat (40).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP02018664A EP1391610A1 (en) | 2002-08-20 | 2002-08-20 | Valve needle and metering device comprising the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP02018664A EP1391610A1 (en) | 2002-08-20 | 2002-08-20 | Valve needle and metering device comprising the same |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| EP1391610A1 true EP1391610A1 (en) | 2004-02-25 |
Family
ID=30775824
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP02018664A Withdrawn EP1391610A1 (en) | 2002-08-20 | 2002-08-20 | Valve needle and metering device comprising the same |
Country Status (1)
| Country | Link |
|---|---|
| EP (1) | EP1391610A1 (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5161743A (en) * | 1986-10-24 | 1992-11-10 | Nippondenso Co., Ltd. | Electromagnetic fuel injection valve for internal combustion engine |
| EP0867611A1 (en) * | 1997-03-26 | 1998-09-30 | Bayerische Motoren Werke Aktiengesellschaft, Patentabteilung AJ-3 | Fuel injection nozzle for an internal combustion engine |
| US6363913B1 (en) * | 2000-06-09 | 2002-04-02 | Caterpillar Inc. | Solid state lift for micrometering in a fuel injector |
| WO2002038948A1 (en) * | 2000-11-13 | 2002-05-16 | Siemens Vdo Automotive Corporation | Magneto-hydraulic compensator for a fuel injector |
-
2002
- 2002-08-20 EP EP02018664A patent/EP1391610A1/en not_active Withdrawn
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5161743A (en) * | 1986-10-24 | 1992-11-10 | Nippondenso Co., Ltd. | Electromagnetic fuel injection valve for internal combustion engine |
| EP0867611A1 (en) * | 1997-03-26 | 1998-09-30 | Bayerische Motoren Werke Aktiengesellschaft, Patentabteilung AJ-3 | Fuel injection nozzle for an internal combustion engine |
| US6363913B1 (en) * | 2000-06-09 | 2002-04-02 | Caterpillar Inc. | Solid state lift for micrometering in a fuel injector |
| WO2002038948A1 (en) * | 2000-11-13 | 2002-05-16 | Siemens Vdo Automotive Corporation | Magneto-hydraulic compensator for a fuel injector |
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Effective date: 20040827 |