GB2338031A - An fuel injection valve, for an I.C. engine, with a piezoelectric actuator and injection orifices of different opening cross section - Google Patents
An fuel injection valve, for an I.C. engine, with a piezoelectric actuator and injection orifices of different opening cross section Download PDFInfo
- Publication number
- GB2338031A GB2338031A GB9912927A GB9912927A GB2338031A GB 2338031 A GB2338031 A GB 2338031A GB 9912927 A GB9912927 A GB 9912927A GB 9912927 A GB9912927 A GB 9912927A GB 2338031 A GB2338031 A GB 2338031A
- Authority
- GB
- United Kingdom
- Prior art keywords
- valve
- piezoelectric devices
- closing means
- injection
- orifices
- 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.)
- Granted
Links
- 238000002347 injection Methods 0.000 title claims abstract description 39
- 239000007924 injection Substances 0.000 title claims abstract description 39
- 239000000446 fuel Substances 0.000 title claims abstract description 10
- 239000000463 material Substances 0.000 claims abstract description 14
- 239000010955 niobium Substances 0.000 claims abstract description 5
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 claims abstract description 4
- 229910052746 lanthanum Inorganic materials 0.000 claims abstract description 4
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 claims abstract description 4
- 229910052758 niobium Inorganic materials 0.000 claims abstract description 4
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 claims abstract description 4
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims abstract description 3
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 claims abstract description 3
- 229910052719 titanium Inorganic materials 0.000 claims abstract description 3
- 239000010936 titanium Substances 0.000 claims abstract description 3
- 229910052726 zirconium Inorganic materials 0.000 claims abstract description 3
- 229910052718 tin Inorganic materials 0.000 claims description 2
- 238000002485 combustion reaction Methods 0.000 abstract description 3
- 239000000919 ceramic Substances 0.000 description 4
- 238000006073 displacement reaction Methods 0.000 description 4
- 230000003321 amplification Effects 0.000 description 3
- 238000003199 nucleic acid amplification method Methods 0.000 description 3
- 238000011161 development Methods 0.000 description 2
- 230000018109 developmental process Effects 0.000 description 2
- 230000005684 electric field Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- 230000003213 activating effect Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
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
- 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
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
- F16K31/00—Actuating devices; Operating means; Releasing devices
- F16K31/004—Actuating devices; Operating means; Releasing devices actuated by piezoelectric means
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N30/00—Piezoelectric or electrostrictive devices
- H10N30/80—Constructional details
- H10N30/85—Piezoelectric or electrostrictive active materials
- H10N30/853—Ceramic compositions
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Mechanical Engineering (AREA)
- Ceramic Engineering (AREA)
- Combustion & Propulsion (AREA)
- Fuel-Injection Apparatus (AREA)
- Magnetically Actuated Valves (AREA)
Abstract
An injector valve, for a fuel injection system of an internal combustion engine, comprises a plurality of piezoelectric devices 2 for actuating the valve, wherein the material provided for the piezoelectric devices 2 is formed from oxides of lead, zirconium and titanium (PZT) and modified by tin and either niobium or lanthanum. The valve also has a valve closing means 4 with a tappet 5 which is displaced relative to housing 6. Modified piezoelectric devices may be provided for the valve closing means 4. The closing means 4 may also have orifices 7 of different opening cross section and where the orifices 7 are provided in at least two rows located axially one behind the other. The piezoelectric material, known as a phase switching material, does not experience expansion until a threshold value is reached whereafter a jump function occurs, with a sharp rise in expansion.
Description
2338031 1 Injection valve The invention relates to an injection valve for
fuel injection systems, with an injector housing, in which a plurality of piezoelectric devices located one behind the other in the axial direction are arranged, and with a valve housing which is connected to the injector housing and in which a valve-closing means is arranged displaceably, a tappet of the valve-closing means being displaced relative to the valve housing, for the release of fuel injection orifices, when a control voltage is applied to the piezoelectric devices.
DE 195 00 706 A1 discloses an injection valve for internal combustion engines, hydraulic travel amplification being provided for converting the actuating travel of a piezoelectric actuator in order to obtain an increased stroke of a tappet needle or valve needle of the closing means. Hydraulic travel amplification is necessary in order to amplify the low expansion when a threshold voltage is applied to the piezoelectric devices, to an extent such that a sufficient displacement of the tappet for the release of the injection orifices is achieved. This means, however, that the injection valve has to have a correspondingly complicated design.
DE 196 16 695 Cl describes a method for producing a piezoelectric actuator of monolithic multi-layer design, there being proposed a monolithic piezoelectric actuator which consists of a stoichiometric PZT ceramic with low Aposition doping and which exhibits improved mechanical strength along with good piezoelectric properties. Here, irrespective of a B-position doping, the production method is intended to lead to optimum grain sizes and optimum piezoelectric properties in the ceramic.
The application on which the present invention is based is, therefore, to provide an injection valve of the type mentioned in the introduction, in which a sufficient adjusting travel for the release of injection orifices is produced, without the need for hydraulic or mechanical step-up aids, whilst at the same time, as required, the injection quantity is also to be variable in relation to the opening travel of the injection holes.
According to the present invention there is provided an injection valve for fuel injection systems, with an injector housing, in which a plurality of piezoelectric 2 devices located one behind the other in the axial direction are arranged, and with a valve housing which is connected to the injector housing and in which a valve-closing means is arranged displaceably, a tappet of the valve-closing means being displaced relative to the valve housing, for the release of fuel injection orifices, when a control voltage is applied to the piezoelectric devices, wherein elementary oxides of lead, zirconium, tin and titanium, which are modified with niobium or lanthanum, are provided as materials for the piezoelectric devices.
It became clear, surprisingly, that phase switcher materials are highly suitable for injection valves. Thus, phase switcher materials experience, for example, approximately four-fold expansion in the relevant load range, which means that a greater displacement of the tappet and/or a smaller overall height of the injection valve can be achieved. In particular, it is no longer necessary, as required, to use mechanical or hydraulic stepup aids for amplifying the adjusting travel.
It is advantageous, furthermore, that phase switcher materials can transmit higher forces, so that it is moreover possible for smaller dimensions to be used for the piezoelectric devices. In general, the piezoelectric devices are designed as discs, with the result that correspondingly smaller disc diameters can be achieved.
In a highly advantageous development of the invention, the phase switcher piezoelectric devices can be used for closing means in which different opening cross sections of the injection holes and/or so-called register nozzles are employed, in particular in which at least two rows of injection orifices located axially one behind the other are provided.
The inventors found, specifically, that, when a threshold voltage is applied, phase switcher materials experience virtually a jump in expansion, in contrast to normal piezoceramics with their linear behaviour. In other words, up to a specific threshold voltage the phase switcher materials do not react, and only after a specific voltage is exceeded does an expansion in volume take place in the form of a jump function at the transition from the anti-ferroelectric phase to the ferroelectric phase, this expansion then increasing only slightly in the event of a further rise in the voltage. When a plurality of plates or discs of phase switcher piezoelectric devices, located axially one behind the other, are used, then, this property is employed in such a way that an expansion behaviour can be achieved in a desired predetermined direction, as 3 a function of the voltage, by a variation in the thickness of the individual piezoelectric layers or discs.
In use in a register nozzle, this means, in concrete terms, that individual register orifices can be activated in a controlled way by means of a specific voltage. If piezoelectric discs of different thickness are used, these then always switch, in each case according to the field strength of the electric field, at the same field strength, that is to say when voltage is applied differently, so that the discs of different thickness can be expanded in succession. In other words: in a specific voltage range, for example, only the first injection-hole row is opened by the register nozzle, whilst, in a second voltage range, a second hole row is opened, and, for example, in a third voltage range a third hole row is opened. Different opening cross sections of the injection holes can likewise be activated correspondingly by means of the phase switcher materials in order to vary the injection quantity.
Advantageous developments and refinements of the invention may be gathered from the embodiment described, in principle, below with reference to the drawing in which:
Figure 1 shows an injection valve with a closing means (partly in section); and Figure 2 shows a graph to illustrate the expansion of piezoelectric devices.
The injection valve of the embodiment is fundamentally of a known design (see, for example, DE 195 00 706 A1), and therefore only the front and rear regions of the injection valve, together with the piezoelectric devices and the closing means, are illustrated in section below for the sake of clarity.
A plurality of piezoelectric devices 2 consisting of phase switcher materials are located one behind the other in the axial direction in an injector housing 1. The phase switcher materials are connected to a tappet 3 of a valve-closing means 4 in a way not illustrated in any more detail. lle piezoelectric devices 2 are designed in the form of discs which may have different thicknesses, so that different activating voltages are generated.
The tappet 3 is provided, at its front end, with a valve member 5 which 4 forms a valve seat in conjunction with a valve housing 6 surrounding the tappet 3. At least two rows of injection orifices 7 are located one behind the other in the axial direction in the valve seat.
When threshold voltages are applied to the piezoelectric discs 2, which may be designed as stack actuators or multi-layer actuators, expansions in volume occur, and consequently a displacement of the tappet 3, such that the injection orifices 7 are freed, so that fuel, which is located under high pressure in a gap space 8 between the valve housing 6 and the tappet 3, can be injected into a combustion space which is not illustrated. In this case, the expansion of the phase switcher piezoelectric devices takes place as a result of a change-over from an anti-ferroelectric state to a ferroelectric state.
As in conventional piezoelectric actuators, plumbo-zirconatetitanate (M) forms the chemical basis of phase-switching ceramic. By modifying this material with the elements tin (Sn) and niobium (Nb) or lanthanum (La), anti-ferroelectric phases can be stabilized within technically relevant temperature ranges. An antiferroelectric phase can be changed to a ferroelectric phase by means of an electric field. This phase transition is associated with an expansion in volume and, in the present case, forms the basis for use in injection valves. The phase-switching ceramics are termed PLM or PNM, depending on the substitution elements involved.
Figure 2 illustrates a simplified graph of the expansion behaviour of normal piezoelectric devices and of phase switcher piezoelectric devices. The ordinate relates to the expansion and the abscissa to the electrical voltage. The stroke behaviour of a standard piezoelectric device is illustrated by the broken line 9 and the stroke behaviour of a phase switcher piezoelectric device by the unbroken line 10. As is evident, in the case of a normal standard piezoelectric device, expansion according to a linear profile commences virtually as soon as a threshold voltage is applied, leads to a maximum expansion point 11 at 4000 V/mm and then returns to 0 again in a hysteresis curve.
By contrast, the stroke behaviour of a phase switcher piezoelectric device experiences no expansion up to a threshold voltage of approximately 3400 Volt. In the voltage range of 3400 V/mm, a jump function occurs, with a sharp rise to an expansion point 12 at a threshold voltage of 4000 V/mm. When the threshold voltage is removed, the expansion returns to 0 again in a hysteresis curve. The curve illustrated in Figure 2 relates to normal pressure. Under pressure load, better expansion occurs by the factor 4.
It is, of course, also possible, however, as required, also to provide mechanical or hydraulic amplification for the tappet displacement, in spite of the markedly improved expansion achieved by phase switcher piezoelectric devices.
The invention may, of course, also be used for inward-opening nozzle needles or tappets. In this case, it is merely necessary to provide a means for reversing the direction of the expansion generated by the phase switcher piezoelectric devices.
6
Claims (5)
1. An injection valve for fuel injection systems, with an injector housing, in which a plurality of piezoelectric devices located one behind the other in the axial direction are arranged, and with a valve housing which is connected to the injector housing and in which a valve-closing means is arranged displaceably, a tappet of the valve-closing means being displaced relative to the valve housing, for the release of fuel injection orifices, when a control voltage is applied to the piezoelectric devices, wherein elementary oxides of lead, zirconium, tin and titanium, which are modified with niobium or lanthanum, are provided as materials for the piezoelectric devices.
2. An injection valve according to Claim 1, wherein the modified piezoelectric devices are provided for a valve-closing means, the injection orifices of which have different opening cross sections.
3. An injection valve according to Claim 1 or 2, wherein the modified piezoelectric devices are provided in conjunction with a closing means which has at least two rows of injection orifices located axially one behind the other.
4. An injection valve according to Claim 2 or 3, wherein the modified piezoelectric devices comprise discs of different thickness.
5. An injection valve for fuel injection systems, substantially as described herein with reference to and as illustrated in the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19824916A DE19824916C1 (en) | 1998-06-04 | 1998-06-04 | Fuel injection valve for i.c. engine fuel injection system e.g. for automobile |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9912927D0 GB9912927D0 (en) | 1999-08-04 |
| GB2338031A true GB2338031A (en) | 1999-12-08 |
| GB2338031B GB2338031B (en) | 2000-04-26 |
Family
ID=7869851
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9912927A Expired - Fee Related GB2338031B (en) | 1998-06-04 | 1999-06-03 | Injection valve |
Country Status (4)
| Country | Link |
|---|---|
| DE (1) | DE19824916C1 (en) |
| FR (1) | FR2779484A1 (en) |
| GB (1) | GB2338031B (en) |
| IT (1) | IT1306568B1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010058029A1 (en) * | 2008-11-24 | 2010-05-27 | Peter Hess | Drive mechanism for moving an object along an axis of motion and microvalve |
| EP2316647A1 (en) * | 2009-11-02 | 2011-05-04 | Seiko Epson Corporation | Liquid ejecting apparatus |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2816010B1 (en) | 2000-10-27 | 2003-04-18 | Renault | FLUID INJECTION DEVICE AND ITS MANUFACTURING METHOD |
| FR2832189B1 (en) | 2001-11-09 | 2004-12-03 | Renault | FIXING DEVICE FOR A FUEL INJECTION SYSTEM FOR AN INTERNAL COMBUSTION ENGINE |
| DE102004031307A1 (en) * | 2004-06-29 | 2006-01-19 | Robert Bosch Gmbh | Process for the production of PZT-based high-performance piezoceramics |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4862029A (en) * | 1987-02-11 | 1989-08-29 | Tosoh Corporation | Actuator |
| EP0713004A1 (en) * | 1994-11-15 | 1996-05-22 | Zexel Corporation | Variable injection hole type fuel injection nozzle |
| GB2296940A (en) * | 1995-01-12 | 1996-07-17 | Bosch Gmbh Robert | Metering valve actuation |
| JPH09124366A (en) * | 1995-10-30 | 1997-05-13 | Hokkai Can Co Ltd | Piezoelectric ceramic |
| GB2318388A (en) * | 1996-10-15 | 1998-04-22 | Bosch Gmbh Robert | Method of operating an electrically-actuated fuel-injection valve for i.c. engines |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4442764A1 (en) * | 1994-12-01 | 1996-06-05 | Bosch Gmbh Robert | Fuel injection valve for internal combustion engines |
| DE19615695C1 (en) * | 1996-04-19 | 1997-07-03 | Siemens Ag | Monolithic multilayer piezo-actuator production |
-
1998
- 1998-06-04 DE DE19824916A patent/DE19824916C1/en not_active Expired - Fee Related
-
1999
- 1999-06-02 FR FR9906942A patent/FR2779484A1/en active Pending
- 1999-06-02 IT IT1999RM000348A patent/IT1306568B1/en active
- 1999-06-03 GB GB9912927A patent/GB2338031B/en not_active Expired - Fee Related
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4862029A (en) * | 1987-02-11 | 1989-08-29 | Tosoh Corporation | Actuator |
| EP0713004A1 (en) * | 1994-11-15 | 1996-05-22 | Zexel Corporation | Variable injection hole type fuel injection nozzle |
| GB2296940A (en) * | 1995-01-12 | 1996-07-17 | Bosch Gmbh Robert | Metering valve actuation |
| JPH09124366A (en) * | 1995-10-30 | 1997-05-13 | Hokkai Can Co Ltd | Piezoelectric ceramic |
| GB2318388A (en) * | 1996-10-15 | 1998-04-22 | Bosch Gmbh Robert | Method of operating an electrically-actuated fuel-injection valve for i.c. engines |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010058029A1 (en) * | 2008-11-24 | 2010-05-27 | Peter Hess | Drive mechanism for moving an object along an axis of motion and microvalve |
| US8777179B2 (en) | 2008-11-24 | 2014-07-15 | Hess Innovation Gmbh | Drive mechanism for the movement of an object along an axis of motion and micro-valve |
| EP2316647A1 (en) * | 2009-11-02 | 2011-05-04 | Seiko Epson Corporation | Liquid ejecting apparatus |
| US8998386B2 (en) | 2009-11-02 | 2015-04-07 | Seiko Epson Corporation | Liquid ejecting apparatus |
| US9144976B2 (en) | 2009-11-02 | 2015-09-29 | Seiko Epson Corporation | Liquid ejecting apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| DE19824916C1 (en) | 1999-09-30 |
| ITRM990348A1 (en) | 2000-12-02 |
| GB2338031B (en) | 2000-04-26 |
| ITRM990348A0 (en) | 1999-06-02 |
| GB9912927D0 (en) | 1999-08-04 |
| IT1306568B1 (en) | 2001-06-18 |
| FR2779484A1 (en) | 1999-12-10 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20050603 |