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 sensing particulate matter by a particulate matter (PM) sensor positioned upstream, or downstream, of a diesel particulate filter in an exhaust system. The PM sensor may include a curved sensor surface having interdigitated electrodes of differing voltages disposed thereon. An inlet may be disposed to capture a sample flow of exhaust from an exhaust flow from a diesel engine. A conduit may be formed to direct the sample flow toward the curved sensor surface in a direction that may form an acute angle with a line normal to the curved sensor surface.
Claims18
A soot sensor comprising:
- a curved sensor surface having interdigitated electrodes of differing voltages disposed thereon;
- an inlet disposed to capture a sample flow of exhaust from an exhaust flow;
- and
- a conduit formed to direct the sample flow toward the curved sensor surface in a direction that forms an acute angle with a line normal to the curved sensor surface, and wherein the conduit includes a first conduit and a second conduit, wherein:
- the first conduit is positioned transverse to an exhaust flow having two or more openings at an upstream side thereof to admit exhaust into the first conduit at separate and differing radial locations in the exhaust flow, the second conduit is toroid shaped and fluidically coupled with the first conduit, and wherein the curved sensor surface is disposed inside the second conduit.
A method of determining a soot concentration level in a flow of exhaust, comprising:
- collecting two or more exhaust flow samples from respective two or more locations within an exhaust flow downstream from a diesel particulate filter;
- and
- directing the flow samples toward a curvilinear sensor surface via a conduit such that the flow samples impact the sensor surface at an acute angle with a line tangent with a curve of the curvilinear sensor surface, wherein
- the conduit includes two conduit sections, and wherein a first conduit section is oriented substantially orthogonal to a direction of the exhaust flow, and a second conduit section is toroidal shaped, and the second conduit section is disposed outside an exhaust passage and is disposed substantially coaxial with a central axis of an exhaust passage which directs an exhaust stream from a diesel engine.
An exhaust gas sensor arrangement, comprising:
- a conduit to convey two or more exhaust gas samples collected from an exhaust stream, the conduit including two or more conduit sections, and wherein one conduit section is toroidal shaped, and the toroidal shaped conduit section is disposed outside an exhaust passage and is disposed substantially coaxial with a central axis of an exhaust passage which directs the exhaust stream from a diesel engine;
- and
- a curved surface having electrically chargeable conductors positioned thereon, and shaped and disposed within the conduit such that a central line of flow of the two or more exhaust gas samples impacts the curved surface at an acute angle.
Dependencies are inferred from the claim text.