# US 7,407,119 B2 · Magnetic circuit using negative magnetic susceptibility > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,407,119 B2 - Document ID: US7407119B2 - Status: Granted - Kind: B2 - Application number: 10/848,000 - Filed: 2004-05-19 - Published: 2005-11-24 - Granted: 2008-08-05 - Earliest claimed: 2004-05-19 - Assignees: Continental Automotive Systems US, Inc. - Inventors: Perry R. Czimmek - Web page: https://patentgrep.com/patent/US7407119B2 ## CPC - F02M 51/0671: {the armature having an elongated valve body attached thereto} - F02M 51/0614: {characterised by arrangement of electromagnets or fixed armature} - B05B 1/3053: {the actuating means being a solenoid} - F02M 61/165: {Filtering elements specially adapted in fuel inlets to injector} - F02M 2200/90: Selection of particular materials - Y10S 239/19: Nozzle materials - Y10S 239/90: Electromagnetically actuated fuel injector having ball and seat type valve - F02M: SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF - B05B: SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES (spray-mixers with nozzles B01F25/72; processes for applying liquids or other fluent materials to surfaces by spraying B05D) - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS ## Abstract A fuel injector for an internal combustion engine including a body, a stator member, an armature, an electromagnetic coil, and a diamagnetic member. The body includes a passage extending along a longitudinal axis between inlet and outlet ends. The armature member is movable with respect to the stator member between a first configuration and a second configuration, and includes a closure member proximate the outlet end and contiguous to a seat in the first configuration, and spaced from the seat in the second configuration. The electromagnetic coil surrounds the passage, is disposed in a housing, and is energizable to provide magnetic flux that moves the armature between the first and second configuration to permit fuel flow through the passage. The diamagnetic member is proximate the electromagnetic coil so that when the electromagnetic coil is energized the magnetic flux flows around the diamagnetic member. ## Claims ### Claim 1 A fuel injector for an internal combustion engine, comprising: a body having a passage extending along a longitudinal axis between inlet and outlet ends; a stator member; an armature member being movable with respect to the stator member between a first. configuration and a second configuration, the armature member including a closure member proximate the outlet end and contiguous to a seat in the first configuration, and spaced from the seat in the second configuration; an electromagnetic coil surrounding the passage, the coil disposed in a housing and being energizable to provide magnetic flux that moves the armature between the first and second configuration to permit fuel flow through the passage between the inlet and outlet ends; and a diamagnetic member proximate the electromagnetic coil so that when the electromagnetic coil is energized the diamagnetic member focuses the magnetic flux to reduce magnetic flux leakage between the stator and the electromagnetic coil; wherein the electromagnetic coil includes a hollow core, the diamagnetic member includes a wall defining a hollow cylinder, the wall having an inner surface and an outer surface, the diamagnetic member being disposed at least partially in the hollow core; and wherein the coil housing surrounds the coil, the inner surface of the wall confronts a portion of the stator, and the outer surface of the wall confronts a portion of the coil. ### Claim 2 (depends on 1) The electromagnetic fuel injector of claim 1, wherein the diamagnetic member is selected from a group of materials consisting essentially of bismuth, pyrolytic graphites, perovskite copper-oxides, alkali-metal tungstenates, vandanates, molybdates, titanate niobates, NaWO3, YBa2Cu3O7, TiBa2Ca2Cu3O3, AIxGa1−xAs, and Cr, Fe selenides, and combinations thereof. ### Claim 3 (depends on 1) The electromagnetic fuel injector of claim 1, wherein a magnetic susceptibility of the diamagnetic member is less than −0.25. ### Claim 4 (depends on 1) The electromagnetic fuel injector of claim 1, wherein a magnetic susceptibility of the diamagnetic member is less than −0.5. ### Claim 5 (depends on 1) The electromagnetic fuel injector of claim 1, wherein a magnetic susceptibility of the diamagnetic member is less than −0.75. ### Claim 6 (depends on 1) The electromagnetic fuel injector of claim 1, wherein the wall of the diamagnetic member has first and second ends, and the diamagnetic member includes a first flange formed at the first end of the wall, and a second flange formed at the second end of the wall, the first and second flanges extending radially outward from the outer surface of the wall to define a bobbin. ### Claim 7 (depends on 6) The electromagnetic fuel injector of claim 6, wherein the electromagnetic coil is disposed proximate the outer surface of the cylindrical wall, and the stator is at least partially disposed proximate the inner surface of the cylindrical wall. ### Claim 8 (depends on 1) The electromagnetic fuel injector of claim 1, wherein the diamagnetic member includes a polymer having a diamagnetic material suspended therein. ### Claim 9 (depends on 6) The electromagnetic fuel injector of claim 6, wherein the diamagnetic member includes a polymer having a diamagnetic material suspended therein. ### Claim 10 (depends on 1) The electromagnetic fuel injector of claim 1, wherein a lower surface of the stator member generally orthogonal to the longitudinal axis, and an upper surface of the armature member generally orthogonal to the longitudinal axis define a working gap, the diamagnetic member directing the magnetic flux through the working gap. ### Claim 11 An actuator including a stator member, an armature member being moveable with respect to the stator member between a first configuration and a second configuration, an electromagnetic coil being energizable to provide magnetic flux that moves the armature between the first and second configuration, and a diamagnetic member proximate the coil, the diamagnetic member having a magnetic susceptibility of less than −0.15 so that when the electromagnetic coil is energized, the diamagnetic member forms a barrier to magnetic flux and assists in moving the armature member between the first and second configuration; wherein the diamagnetic member includes a wall defining a hollow cylinder, the wall having an inner surface and an outer surface, and first and second ends; and wherein the diamagnetic member includes a first flange formed at the first end of the wall, and a second flange formed at the second end of the wall, the first and second flanges extending radially outward from the outer surface of the wall to define a bobbin. ### Claim 12 (depends on 11) The actuator of claim 11, wherein a thickness of the wall is approximately 20 microns or greater. ### Claim 13 (depends on 11) The actuator of claim 11, wherein the diamagnetic member includes a polymer having a diamagnetic material suspended therein.