Exhaust geometry for particle grouping

An exhaust pipe for a combustion engine, the exhaust pipe comprising:

• a hollow body, the hollow body including:
• an internal surface;
• an external surface;
• a first open end;
• a second open end;
• and
• a longitudinal axis,
• the hollow body forming an exhaust flow conduit between the first open end and the second open end;
• the first open end having a first cross-sectional area perpendicular to the direction of a received exhaust flow therethrough;
• the conduit having a variable cross-sectional area extending from the first cross-sectional area along at least a portion of the longitudinal length of the conduit;
• wherein the variable cross-sectional area throughout the at least a portion of the longitudinal length is equal to or greater than the first cross-sectional area;
• wherein the internal surface is shaped to form a standing cyclic wave geometry having at least two cycles when the combustion engine is at a selected engine speed;
• wherein gas containing inhalable particles enters the exhaust pipe through the first open end and flows out of the exhaust pipe through the second open end;
• and
• wherein the hollow body is configured such that the gas flow causes the inhalable particles to group into filterable particles within the exhaust pipe.

An exhaust component for enhancing generation of filterable particles from engine exhaust, the exhaust component comprising:

• an exhaust component inlet coupleable to an exhaust outlet of a combustion engine, the combustion engine in operation producing an engine exhaust having at least one exhaust flow characteristic, the exhaust component inlet having an outer wall and an opening therethrough, the opening having a first cross-sectional area perpendicular to the direction of a received exhaust flow therethrough;
• a flow cycling section communicably coupled to the exhaust component inlet, the flow cycling section including:
• a plurality of sub-sections, each of the plurality of subsections having an outer sub-section wall forming an exhaust flow conduit between a subsection inlet and a subsection outlet, the conduit varying in cross-sectional area along at least a portion of conduit, wherein the cross-sectional area is equal to or greater than the first cross-sectional area at the subsection inlet and greater than the cross-sectional area at the subsection outlet, and wherein the cross-sectional area of the conduit increases along the conduit length from the subsection inlet to maximum cross-sectional area, and decreases from the maximum cross-sectional area to the subsection outlet;
• wherein the plurality of sub-sections in the flow cycling section each have a length and variation in the cross-sectional area configured for the at least one exhaust flow characteristic of the combustion engine, such that cyclic flow occurs within the plurality of subsections, the cyclic flow inducing particle grouping and coagulation.

An exhaust pipe for use with an internal combustion engine, the exhaust pipe comprising:

• a flow cycling section having a plurality of sub-sections, each of the plurality of subsections including:
• a subsection inlet having an outer wall and an opening therethrough;
• an outer sub-section wall forming a conduit coextensive with the subsection inlet, the conduit having a length and varying in cross-sectional area along at least a portion of the conduit length, wherein the varying cross-sectional area along the conduit length increases between the subsection inlet to a maximum, and decreases from the maximum;
• and
• a subsection outlet coextensive with conduit at a point along the length of the conduit beyond the maximum;
• wherein the plurality of sub-sections in the flow cycling section each have a length and variation in the cross-sectional area along the length that is configured for at least one flow characteristic of an exhaust flow from an attached combustion engine, such that cyclic flow occurs within the plurality of subsections, the cyclic flow inducing filterable size particle grouping and coagulation in the exhaust flow.