Source: http://www.google.com/patents/US5740969?dq=5,884,272
Timestamp: 2014-03-07 17:49:48
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Patent US5740969 - Piezo-control valve for fuel injection systems of internal combustion engines - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsIn a piezo-control valve for fuel injection systems of internal combustion engines wherein a piezo-ceramic actuating rod is mounted with one end firmly to one end of a valve housing having a nozzle body with a valve seat disposed at the other end and a nozzle control needle is disposed in the nozzle...http://www.google.com/patents/US5740969?utm_source=gb-gplus-sharePatent US5740969 - Piezo-control valve for fuel injection systems of internal combustion enginesAdvanced Patent SearchPublication numberUS5740969 APublication typeGrantApplication numberUS 08/728,342Publication dateApr 21, 1998Filing dateOct 9, 1996Priority dateOct 18, 1995Fee statusPaidAlso published asDE19538791A1, DE19538791C2Publication number08728342, 728342, US 5740969 A, US 5740969A, US-A-5740969, US5740969 A, US5740969AInventorsKarl-Heinz Hoffmann, Gerd Huber, Paul SchwerdtOriginal AssigneeMercedes-Benz AgExport CitationBiBTeX, EndNote, RefManPatent Citations (7), Non-Patent Citations (2), Referenced by (27), Classifications (18), Legal Events (8) External Links: USPTO, USPTO Assignment, EspacenetPiezo-control valve for fuel injection systems of internal combustion enginesUS 5740969 AAbstract In a piezo-control valve for fuel injection systems of internal combustion engines wherein a piezo-ceramic actuating rod is mounted with one end firmly to one end of a valve housing having a nozzle body with a valve seat disposed at the other end and a nozzle control needle is disposed in the nozzle body and pressed by the piezo-ceramic actuating rod onto the valve seat in the nozzle body when the piezo-ceramic actuating rod is not activated, the valve housing includes a sleeve-like portion disposed around the piezo-ceramic actuating rod which consists of a material compensating for temperature-caused changes in the length of the piezo-ceramic actuating rod.
What is claimed is: 1. A piezo control valve for fuel injection systems of internal combustion engines comprising:a valve housing including a piezo-ceramic actuating rod having one end firmly mounted to one end of said valve housing, a nozzle body with a valve seat disposed at the other end of said valve housing, and a nozzle control needle which is disposed at the opposite end of said piezo-ceramic actuating rod and is normally seated on said valve seat and which, upon activation of said piezo-ceramic actuating rod, is lifted, by contraction of said piezo-ceramic actuating rod, from said valve seat to open said control valve, said valve housing surrounding said piezo-ceramic actuating rod including a sleeve-like portion consisting of a material compensating for any temperature-caused changes in length of the piezo-ceramic actuating rod. 2. A piezo control valve according to claim 1, wherein said sleeve-like valve housing portion comprises two sleeve parts axially attached to one another and consisting of different materials with different temperature expansion coefficients.
3. A piezo control valve according to claim 1, wherein, between said nozzle control needle and said piezo-ceramic actuating rod, an intermediate member is disposed and is attached to said piezo-ceramic actuating rod, said intermediate member having a front face which is flush with an adjacent end face of said sleeve-like valve housing portion.
4. A piezo control valve according to claim 3, wherein said valve seat is arranged in a nozzle body at the other end of said valve housing and a pressure space extends around said control needle in said nozzle body, said nozzle body including a fuel supply passage leading to said pressure space, and the rear end of said control needle opposite said valve seat being flush with said nozzle body when said control needle is seated on said valve seat.
5. A piezo control valve according to claim 4, wherein an intermediate disc of a given thickness is disposed between said rear end of said control needle and said intermediate member mounted to the end of said piezo-ceramic actuating rod and a washer of a given thickness is disposed between the sleeve portion and said nozzle body concentrically around said intermediate disc, wherein the thickness of said intermediate disc is slightly greater than the thickness of said washer so as to provide for resilient compression of said actuating rod when said nozzle body is mounted onto said sleeve-like housing portion.
6. A piezo control valve according to claim 1, wherein said valve housing includes two sleeve parts extending around said actuating rod, one of said sleeve parts adjacent said nozzle body consisting of steel and the other of Invar, the lengths of said two sleeve parts being so selected that their combined thermal expansion rate is essentially the same as that of said actuating rod so that the travel distance of said control needle is independent of temperature variations.
BACKGROUND OF THE INVENTION The invention relates to a piezo-control valve having an end nozzle for fuel injection systems of internal combustion engines and a piezo-ceramic structure which is supported in a valve housing and has a needle-like closing portion seated on a valve seat and cooperating with a piezo actuation rod firmly mounted in the valve housing end remote from the end nozzle such that the needle-like closing portion is lifted off the valve seat when the piezo actuation rod is activated.
A magnetostrictive or piezo-ceramic fuel injection valve with a closing member disposed on a valve seat is known for example from DE 29 31 874 C2. The valve includes a magnetostrictive rod which has a valve closing end and which, at the opposite end, is connected to a support structure capable of moving axially and dampening axial movements so that the rod is somehow floatingly supported whereby different heat expansion of the valve housing and the arrangement controlling the valve lift can be accommodated.
However, with this arrangement, the valve lift may vary somewhat depending on the temperature so that a particular control signal does not always generate the same valve lift.
It is the object of the present invention to provide a simple and space-saving piezo-control valve of the type referred to above wherein the valve lift which corresponds to the engine requirements is always the same independently of temperature changes.
SUMMARY OF THE INVENTION In a piezo-control valve for fuel injection systems of internal combustion engines wherein a piezo-ceramic actuating rod is mounted with one end firmly to one end of a valve housing having a nozzle body with a valve seat disposed at the other end and a nozzle control needle is disposed in the nozzle body and pressed by the piezo-ceramic actuating rod onto the valve seat in the nozzle body when the piezo-ceramic actuating rod is not activated, the valve housing includes a sleeve-like portion disposed around the piezo-ceramic actuating rod which consists of a material compensating for temperature-caused changes in the length of the piezo-ceramic actuating rod.
With the arrangement according to the invention the valve housing is expanding essentially at the same rate as the rod-like piezo-ceramic actuating rod whereby, in addition to achieving the high control speed required for today's internal combustion engines, the injection pattern can be controlled in an accurate manner particularly with extremely high pressure systems such as common rail fuel injection systems.
An embodiment of the invention will be described below on the basis of the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING The sole FIGURE is a cross-sectional view of a fuel injection valve according to the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT A piezo-control valve 1 for a fuel injection system such as a Diesel engine injection system comprises essentially an elongated valve housing 5, a piezo ceramic device 2 disposed in the valve housing 5 and a nozzle body 3 with a nozzle control needle 4 axially movably disposed in the nozzle body 3. The valve housing 5 is a sleeve-like member preferably consisting of two coaxial sleeve parts 5a, 5b which consist of materials with different heat expansion coefficients.
The piezo-ceramic device 2 includes a rod-like piezo actuator 6 whose one end is disposed adjacent the nozzle control needle 4 and whose opposite end is firmly mounted on a disc-like end piece 7 which is supported at the adjacent end of the sleeve part 5a and fixed by a pin 8 so as to be non-rotatable with respect to the sleeve part 5a. The disc-like end piece 7 is firmly mounted onto the free end of the sleeve part 5a by means of a cup nut 9.
At its end adjacent the control needle 4, the piezo-actuator 6 which contracts when activated is firmly connected to an intermediate member 10. The front face 10a of this intermediate member 10 and the end face 5c of the housing sleeve part 5b are ground so as to be flush with respect to each other. The end face 4a of the nozzle control needle 4 and the front end 3a of the nozzle body 3 adjacent the intermediate member front face 10a are also ground flush.
In order to prevent fuel leakage along the valve seat 13 when the piezo actuator 6 is seated on the nozzle control needle 4 via the intermediate member 10 the nozzle control needle 4 must be engaged with the valve seat 13 with a force which is higher than the lifting force generated by the fuel pressure. This is achieved by threading the component assembly 5, 7, 9, 6, 10 onto the nozzle body 3 such that the front face 10a of the intermediate member 10 firmly presses the control needle 4 onto the valve seat 13 by way of an intermediate disc 11. The sleeve part 5b and the nozzle body 3 are in engagement with one another by way of an intermediate washer 12 which is thinner than the intermediate disc 11 by a system-specific accurate amount which in the present case is 0.035 mm. This amount causes an elastic compression of the piezo actuator which generates the required seating force for the control needle 4.
The reference numeral 14 designates a fuel supply passage which leads to a pressure space 15 formed between the nozzle control needle 4 and the nozzle body 3. The two part valve housing sleeve 5 consists of different materials. Specifically, the lower sleeve part 5b consists of normal steel whereas the upper sleeve part 5a consists of Invar.
In order to achieve essentially the same temperature expansion for the piezoactuator 6 at one hand and the two-part valve housing sleeve on the other, the axial lengths of the sleeve part 5b of steel and the sleeve part 5a of Invar are so selected that the sum of the heat expansion of the sleeve parts 5a and 5b corresponds to the heat expansion of the piezo actuator 6, that is, the heat expansion of the sleeve parts 5a and 5b compensates for the heat expansion of the rod-like piezo actuator 6.
Instead of the two part valve housing sleeve, a single part valve housing sleeve can be utilized which consists of a material having a heat expansion coefficient corresponding to that of the piezo actuator rod 6.
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS4284263 *May 7, 1979Aug 18, 1981U.S. Philips CorporationTemperature-compensated control valveUS4720077 *Dec 22, 1986Jan 19, 1988Aisan Kogyo Kabushiki KaishaFuel injection valveUS4725002 *Sep 11, 1986Feb 16, 1988Robert Bosch GmbhMeasuring valve for dosing liquids or gasesUS5094430 *Mar 4, 1991Mar 10, 1992Stec, Inc.Control valveUS5224510 *Oct 31, 1990Jul 6, 1993Ciba-Geigy CorporationValveDE2931874A1 *Aug 6, 1979Feb 12, 1981Audi Nsu Auto Union AgElektrisch betaetigbares ventilWO1985002445A1 *Nov 20, 1984Jun 6, 1985Kockums AbControl means for precision control of valves* Cited by examinerNon-Patent CitationsReference1Martin Romphorst, "Ein Neues Elektronisches Hochdruck-Einspritzsystem fur Dieselmotoren", MTZ Motortechnische Zeitschrift, 1995, pp. 142-148.2 *Martin Romphorst, Ein Neues Elektronisches Hochdruck Einspritzsystem f u r Dieselmotoren , MTZ Motortechnische Zeitschrift, 1995, pp. 142 148.* Cited by examinerReferenced byCiting PatentFiling datePublication dateApplicantTitleUS6170526 *May 18, 1999Jan 9, 2001Caterpillar Inc.Piezoelectric actuated poppet valve to modulate pilot pressures and control main valve activationUS6173913Aug 25, 1999Jan 16, 2001Caterpillar Inc.Ceramic check for a fuel injectorUS6206341 *Mar 30, 2000Mar 27, 2001Caterpillar Inc.Piezoelectric actuated poppet valve to modulate pilot pressures and control main valve activationUS6313568Dec 1, 1999Nov 6, 2001Cummins Inc.Piezoelectric actuator and valve assembly with thermal expansion compensationUS6345771Jun 30, 2000Feb 12, 2002Siemens Automotive CorporationMultiple stack piezoelectric actuator for a fuel injectorUS6400066Jun 30, 2000Jun 4, 2002Siemens Automotive CorporationElectronic compensator for a piezoelectric actuatorUS6499471Jun 1, 2001Dec 31, 2002Siemens Automotive CorporationHydraulic compensator for a piezoelectrical fuel injectorUS6526864Apr 17, 2001Mar 4, 2003Csa Engineering, Inc.Piezoelectrically actuated single-stage servovalveUS6650032Jun 3, 2002Nov 18, 2003Siemens Automotive CorporationElectronic compensator for a piezoelectric actuatorUS6705587May 4, 2000Mar 16, 2004Siemens AktiengesellschaftMethod for positioning the actuating drive in a fuel injector device for implementing said methodUS6766965Aug 31, 2001Jul 27, 2004Siemens Automotive CorporationTwin tube hydraulic compensator for a fuel injectorUS6772963 *May 7, 2002Aug 10, 2004Magneti Marelli Powertrain S.P.A.Fuel injector with a piezoelectric actuator housed in an insulated chamberUS6776390 *Aug 1, 2000Aug 17, 2004Robert Bosch GmbhValve for controlling fluidsUS6971172 *Aug 8, 2003Dec 6, 2005Cummins Inc.Piezoelectric control valve adjustment methodUS7310986Jan 16, 2004Dec 25, 2007Siemens AktiengesellschaftMethod for producing a compensation collar for an injection valveUS7504762Oct 12, 2004Mar 17, 2009Siemens AktiengesellschaftReceiving sleeve for a piezoelectric actuatorUS7514847 *Jan 11, 2005Apr 7, 2009Siemens AktiengesellschaftPiezo actuator comprising means for compensating thermal length modifications and fuel injection valve comprising a piezo actuatorUS7665445Apr 18, 2008Feb 23, 2010Caterpillar Inc.Motion coupler for a piezoelectric actuatorUS7913929 *Nov 18, 2008Mar 29, 2011Continental Automotive Systems Us, Inc.Modular outward opening piezo direct fuel injectorUS7992395 *Jan 17, 2006Aug 9, 2011Hussmann CorporationExpansion valve with piezo materialUS8368288 *Jul 15, 2008Feb 5, 2013Continental Automotive GmbhActuator unit for an injection system of an internal combustion engineUS20100194244 *Jul 15, 2008Aug 5, 2010Dick JuergenActuator unit for an injection system of an internal combustion engineCN100416084CJan 11, 2005Sep 3, 2008西门子公司Piezo actuator comprising means for compensating thermal length modifications and fuel-injection valve comprising a piezo actuatorEP1505295A1 *May 4, 2000Feb 9, 2005Siemens AktiengesellschaftMethod of positioning an actuator of a fuel injector and apparatus to carry out the methodWO2000068563A2 *May 4, 2000Nov 16, 2000Wilhelm FrankMethod for positioning the actuating drive in a fuel injector and device for implementing said methodWO2001014731A1 *Aug 1, 2000Mar 1, 2001Friedrich BoeckingValve for controlling the flow of liquidsWO2001055578A2 *Jan 25, 2001Aug 2, 2001Friedrich BoeckingInjection nozzle* Cited by examinerClassifications U.S. Classification239/533.2, 251/129.6, 239/584International ClassificationF02M61/16, F02M51/06, F02M63/00, F16K31/00, H02N2/02, H02N2/04, F02M59/46Cooperative ClassificationF02M63/0026, F16K31/007, F02M61/166, F02M61/167European ClassificationF02M63/00E2B4, F16K31/00E3, F02M61/16G, F02M61/16FLegal EventsDateCodeEventDescriptionOct 14, 2009FPAYFee paymentYear of fee payment: 12Apr 24, 2009ASAssignmentOwner name: DAIMLER AG, GERMANYFree format text: CHANGE OF NAME;ASSIGNOR:DAIMLERCHRYSLER AG;REEL/FRAME:022846/0912Effective date: 20071019Free format text: CHANGE OF NAME;ASSIGNOR:DAIMLERCHRYSLER 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PAUL;REEL/FRAME:008258/0892Effective date: 19961001RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services©2012 Google