Variable reluctance position sensor

• US 20070068499A1
• Filed: 09/26/2005
• Published: 03/29/2007
• Est. Priority Date: 09/26/2005
• Status: Active Grant

• Current Assignee: Cummins Incorporated
• Original Assignee: Cummins Incorporated
• Inventors: Schuppe, Alfred, Schneider, Matthew
• Granted Patent: US 7,302,940 B2
• Time in Patent Office: Days
• US Class Current: 123/568.160
• CPC Class Codes: F02M 26/48 EGR valve position sensors details of the sensor installation in the valve housing F02M26/72
• CPC Class Codes: F02M 26/54 Rotary actuators, e.g. step motors
• CPC Class Codes: F02M 26/72 Housings
• CPC Class Codes: G01D 2205/775 Tapered profiles
• CPC Class Codes: G01D 5/2013 by a movable ferromagnetic element, e.g. a core G01D5/2033 takes precedence

Abstract

A position sensor is disclosed having a transducer formed by a Hall-effect device and permanent magnet secured within a housing on either side of a low permeability gap. A target secured to an active member, such as an EGR valve plunger moves within the gap. The target has a flux modulating property that varies with position along a direction of travel. In one embodiment, the reluctance of the target varies with position. Variable reluctance is achieved in some embodiments by varying the cross section of the target with position. In some embodiments, a second target having substantially constant reluctance secures to the active member and moves within a gap defined by a second transducer. The output of the second transducer is used to normalize the output of the first transducer and compensate for anomalies such as drift and movement other than in the direction of travel of the active member.

Claims