Exhaust geometry for particle grouping

Abstract

An exhaust pipe for a fuel burning engine including a hollow body, the body having an internal surface, an external surface, a first open end, a second open end and a longitudinal axis, wherein the internal surface is shaped to form standing cyclic wave geometry having at least 2 cycles (c). When 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, a substantial amount of inhalable particles are grouped to form filterable particles.

1 - 9 . (canceled) 
     
     
         10 . 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.   
     
     
         11 . The exhaust pipe of  claim 10 , wherein the longitudinal axis is disposed horizontally. 
     
     
         12 . The exhaust pipe of  claim 10 , wherein the longitudinal axis is disposed vertically, and wherein the second open end is elevated with respect to said first open end. 
     
     
         13 . The exhaust pipe of  claim 10 , wherein the longitudinal axis is disposed diagonally, and wherein the second open end is elevated with respect to said first open end. 
     
     
         14 . The exhaust pipe of  claim 10 , wherein the standing cyclic wave includes a narrow radial dimension D N  and a wide radial dimension D W , wherein said narrow radial dimension D N  is less than said wide radial dimension D W . 
     
     
         15 . The exhaust pipe of  claim 14 , wherein a ratio D W /D N  is larger than 1 and increase in the magnitude of the ratio corresponds to increase in the grouping and coagulation of filterable particles. 
     
     
         16 . The exhaust pipe of  claim 10 , wherein the shape of at least a portion of the cross sectional area of the exhaust pipe has a form selected from a group consisting of radial, polygonal, and elliptical. 
     
     
         17 . The exhaust pipe of  claim 10 , wherein a velocity of the gas flow designated by a function U is:
     U=U   a   −U   b  cos( kx )(sin(ω t )+ C ),
   where U a  is an average velocity, C is constant, U b  is a velocity amplitude, ω is an angular velocity of the wave: ω=2π/T wherein T is a time to complete one wave cycle, or ω=2πf where f is the oscillating frequency of the inlet oscillations, k is a wave number: k=2π/L wherein L is said wave length; and   wherein the constant C is selected to achieve a maximal velocity at D N  and a minimal velocity at D W .   
     
     
         18 . The exhaust pipe of  claim 17 , wherein a non-dimensional velocity field U* is, wherein an asterisk ‘*’ designates a non-dimensional value:
     U*=U*   a   −U*   b  cos( x *)(sin( t *)+ C ), 
 wherein U a  and U b  are normalized with a characteristic velocity: U c , wherein U c =ω/k; x is normalized with k and t with ω; and 
 wherein grouping of filterable particles occurs when: (U* a −1)/U* b <1. 
 
     
     
         19 . The exhaust pipe of  claim 18 , wherein, for the dimensional form of the ratio (U a −fL)/U b <1, the term fL indicates that the grouping of filterable particles is a function of both the inlet frequency and the length of the pipe sections or modules. 
     
     
         20 . The exhaust pipe of  claim 10 , wherein the hollow body is free of exhaust flow inhibiting interior structures. 
     
     
         21 . The exhaust pipe of  claim 10 , wherein the filterable particles group in the absence of another fluid being added to the exhaust flow. 
     
     
         22 . 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.   
     
     
         23 . The exhaust component of  claim 22 , further comprising:
 an exhaust component outlet coupled to the flow cycling section, the exhaust component outlet having an outer wall and an opening therethrough;   
     
     
         24 . The exhaust component of  claim 22 , wherein the induced particle grouping and coagulation produces particles of a filterable size. 
     
     
         25 . The exhaust component of  claim 22 , wherein the flow cycling section is free of restrictions producing resistance pressure on the received exhaust flow greater than pressure on the received exhaust flow for a conventional exhaust pipe. 
     
     
         26 . The exhaust component of  claim 22 , wherein the at least one exhaust flow characteristic of the engine exhaust includes a cyclic exhaust flow. 
     
     
         27 . The exhaust component of  claim 22 , wherein the plurality of sub-sections in the flow cycling section each have a length and variation in the cross-sectional area that is configured to produce a standing wave in the exhaust flow. 
     
     
         28 . The exhaust component of  claim 22 , wherein the plurality of exhaust flow conduits are free of exhaust flow inhibiting interior structures. 
     
     
         29 . The exhaust component of  claim 22 , wherein the filterable particles group in the absence of the addition of another fluid. 
     
     
         30 . 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.   
     
     
         31 . The exhaust pipe of  claim 30 , wherein the conduit is free of exhaust flow inhibiting interior structures. 
     
     
         32 . The exhaust pipe of  claim 30 , wherein the filterable size particles group in the absence of another added fluid.