# US 10,770,212 B2 · Determining armature stroke by measuring magnetic hysteresis curves > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,770,212 B2 - Document ID: US10770212B2 - Status: Granted - Kind: B2 - Application number: 16/065,001 - Filed: 2016-11-28 - Published: 2019-01-03 - Granted: 2020-09-08 - Earliest claimed: 2015-12-21 - Assignees: Robert Bosch GmbH - Applicants: Robert Bosch GmbH - Inventors: Gerald Aydt; Klemens Steinberg; Marco Beier; Markus Rueckle; Oezguer Tuerker - Web page: https://patentgrep.com/patent/US10770212B2 ## CPC - H01F 7/1844: {Monitoring or fail-safe circuits (for relays H01H47/002)} - F02D 41/20: Output circuits, e.g. for controlling currents in command coils - F02D 41/2432: {Methods of calibration} - F02D 41/2467: {for injectors} - H01F 7/18: Circuit arrangements for obtaining desired operating characteristics, e.g. for slow operation, for sequential energisation of windings, for high-speed energisation of windings - F02M 65/00: Testing fuel-injection apparatus, e.g. testing injection timing {(testing of ignition F02P17/00; measuring fuel consumption G01F9/00); Cleaning of fuel-injection apparatus} - H01F 2007/1855: {using a stored table to deduce one variable from another} - H01F 2007/1861: {using derivative of measured variable} - H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES - F02D: CONTROLLING COMBUSTION ENGINES (vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed B60K31/00; conjoint control of vehicle sub-units of different type or different function, road vehicle drive control systems for purposes other than the control of a single sub-unit B60W) - F02M: SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF ## Abstract The invention relates to a method for producing a valve (1) that can be electromagnetically actuated which method comprises an electromagnet (2, 2a, 2b), an armature (3) that can be moved by the electromagnet (2, 2a, 2b), and a valve body (5), having means (4, 4a, 4b, 4c) for converting a movement of the armature (3) into an opening or closing of the valve (1), wherein the electromagnet (2, 2a, 2b) and the armature (3) are inserted into the valve body (5), wherein, before the electromagnet (2, 2a, 2b) is inserted into the valve body (5), a magnetic hysteresis curve (10) of a combination (6) of the electromagnet (2, 2a, 2b) having a test armature (3a) lying against said electromagnet (2, 2a, 2b) is recorded, the slope m1 of a first, substantially linear curve segment (11) of the hysteresis curve (10) is determined in the unsaturated state, and, from the slope m1, the slope m1* of a curve segment (31) of a hysteresis curve (30) of the finally assembled valve (1) having the armature (3) lying continuously against the electromagnet (2, 2a, 2b) is determined, said curve segment corresponding to the first curve segment (11). The invention further relates to a method for determining the armature stroke AH, wherein the magnetic energy ΔE in the air gap (9) formed between the armature (3) and the electromagnet (2, 2a, 2b) is evaluated from the difference between the first slope m0 and the second slope m1*. ## Claims ### Claim 1 A method for ascertaining a hysteresis curve of an electromagnetically actuatable valve (1) made of an electromagnet (2, 2a, 2b), an armature (3) that is movable by way of the electromagnet (2, 2a, 2b), and a valve body (5) with means (4, 4a, 4b, 4c) for converting a movement of the armature (3) into opening or closing of the valve (1), wherein the electromagnet (2, 2a, 2b) and the armature (3) are inserted into the valve body (5), the method comprising recording a magnetic hysteresis curve (10) of a combination (6) of the electromagnet (2, 2a, 2b) with a test armature (3a) contacting said electromagnet (2, 2a, 2b) prior to inserting the electromagnet (2, 2a, 2b) into the valve body (5), ascertaining the slope m1 of a first, substantially linear curve portion (11) of the hysteresis curve (10) in an unsaturated state, and ascertaining, from the slope m1, the slope m1* of a curve portion (31), corresponding to the first curve portion (11), of a hysteresis curve (30) of the fully assembled valve (1) with an armature (3) permanently in contact with the electromagnet (2, 2a, 2b). ### Claim 2 (depends on 1) The method as claimed in claim 1, characterized in that the slope m1* is ascertained by way of a specified first functional relationship from the slope m1. ### Claim 3 (depends on 2) The method as claimed in claim 2, characterized in that the armature (3) is fastened to the electromagnet (2, 2a, 2b) on at least one fully assembled valve (1) and the hysteresis curve (30) is recorded in this state for the purposes of ascertaining the first functional relationship. ### Claim 4 (depends on 1) The method as claimed in claim 1, characterized in that the slope m2 of a second, substantially linear curve portion (12) of the hysteresis curve (10) of the combination (6) is additionally ascertained in the saturated state prior to inserting the electromagnet (2, 2a, 2b) into the valve body (5). ### Claim 5 (depends on 4) The method as claimed in claim 4, characterized in that the current I0 at which a linear continuation (13) of the second curve portion (12) toward the current axis I intersects the current axis I is additionally ascertained. ### Claim 6 (depends on 4) The method as claimed in claim 4, characterized in that a further magnetic hysteresis curve (20) of the valve (1) is recorded after assembling the valve (1), wherein the slope m3 of a second, substantially linear curve portion (22) of the further magnetic hysteresis curve (20), corresponding to the second curve portion (12) of the magnetic hysteresis curve (10), in the saturated state is ascertained. ### Claim 7 (depends on 6) The method as claimed in claim 6, characterized in that the current I1 at which a linear continuation (23) of the second curve portion (22) toward the current axis I intersects the current axis I is additionally ascertained. ### Claim 8 (depends on 7) The method as claimed in claim 7, characterized in that the difference in terms of magnitude ΔI between the current I1 and the current I0 is ascertained and the valve (1) is classified as faulty if the difference in terms of magnitude ΔI exceeds a specified threshold value. ### Claim 9 (depends on 2) The method as claimed in claim 2, characterized in that a correlation and/or a second functional relationship (8) between the slopes m1 and m2 is ascertained from the slopes m1 and m2. ### Claim 10 (depends on 9) The method as claimed in claim 9, characterized in that the second functional relationship (8) establishes a linear relationship between the ratio m2/m1 and the current value I0. ### Claim 11 (depends on 1) The method as claimed in claim 1, characterized in that the slope m1, the slope m2, the slope m1*, and/or the first functional relationship, and/or the second functional relationship (8), and/or the correlation between the slopes m1 and m2 is noted on the electromagnet (2, 2a, 2b), and/or on a machine-readable information carrier (7) connected to the electromagnet (2, 2a, 2b) and/or unambiguously linked to the electromagnet (2, 2a, 2b) in a database. ### Claim 12 (depends on 1) The method as claimed in claim 1, characterized in that a multiplicity of electromagnets (2, 2a, 2b) are classified according to the value of the slopes m1 and/or m2, and/or according to the second functional relationship (8) and/or the correlation between the slopes m1 and m2. ### Claim 13 A method for determining an armature stroke (AH) on an electromagnetically actuatable valve (1) comprising an electromagnet (2, 2a, 2b) and an armature (3) that is movable by the electromagnet (2, 2a, 2b), the method comprising recording a magnetic hysteresis curve (20) of the valve (1), determining a first slope m0 of a first, substantially linear curve portion (21) of the hysteresis curve (20) of the valve (1) in the unsaturated state, and evaluating the magnetic energy ΔE in the air gap (9) formed between the armature (3) and the electromagnet (2, 2a, 2b) from the difference between the first slope m0 and a second slope m1* of the first, substantially linear curve portion (11), corresponding to the first curve portion (21) of the hysteresis curve (20), of a further magnetic hysteresis curve (10), which the valve (1) would have in the case of an armature (3) secured on the electromagnet (2, 2a, 2b). ### Claim 14 (depends on 13) The method as claimed in claim 13, wherein the valve (1) comprises a valve body (5) and wherein the electromagnet (2, 2a, 2b), the armature (3), and means (4, 4a, 4b, 4c) for converting a movement of the armature (3) into an opening or closing of the valve (1) are arranged within the valve body (5), characterized in that, for the purposes of ascertaining the second slope m1*, at least one reference value m1 that was ascertained prior to inserting the electromagnet (2, 2a, 2b) into the valve body (5) is used for said slope m1*. ### Claim 15 (depends on 13) The method as claimed in claim 13, characterized in that the second slope m1* is ascertained from the slope m3 of a second linear curve portion (22) of the magnetic hysteresis curve (20) of the valve (1) in the saturated state in conjunction with a second functional relationship (8) and/or a correlation between the slopes m1, m2 of curve portions (11, 12) of the further hysteresis curve (10).