Method and system for exhaust particulate matter sensing
AssigneeFord Global Technologies, LLC
InventorXiaogang Zhang
Life of this patent
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Abstract
Methods and systems are provided for a particulate matter (PM) sensor assembly positioned downstream of a diesel particulate filter in an exhaust system. In one example, a method may include rotating the PM sensor assembly inside an exhaust passage to generate an output, the rotation based on exhaust flow conditions within the exhaust passage. By rotating the PM sensor assembly via a bearing, a rate of soot particulate accumulation on a sensor element of the assembly may be maintained at a desired level, and independent of a direction of exhaust flow inside the exhaust passage.
Claims20
A method, comprising:
- while exhaust is flowing through an exhaust passage, generating an output from a rotatable, particulate matter (PM) sensor assembly coupled to the exhaust passage, rotation of the rotatable PM sensor assembly changing as exhaust flow conditions change.
A particulate matter (PM) sensor, comprising:
- a protection tube having a sensor element;
- a pair of plates having perforations, the pair of plates coupled to one side of the protection tube and separated from each other by a gap;
- a flow entrance formed on the one side of the protection tube, the flow entrance contiguous with the gap and positioned in between the pair of plates, the sensor element facing the flow entrance;
- a sensor cap and a gasket holder coupling the protection tube to an exhaust pipe;
- and
- a bearing arranged between an inner surface of the sensor cap and an outer surface of the gasket holder rotatably mounting the PM sensor to the exhaust pipe.
A particulate matter (PM) assembly, comprising:
- a hollow, cylindrical tube rotatably mounted to an exhaust passage via ball bearings and rotatable about a central axis;
- a sensor element coaxial with the central axis and coupled to a tube top;
- a cut-out only one side of the tube;
- and
- a pair of parallel flow plates coupled to the one side of the tube and separated by a gap defined by a width of the cut-out.
Dependencies are inferred from the claim text.