Exhaust gas aspirator
View Patent ↗According to one representative embodiment, an aspirator for cooling exhaust gas from an internal combustion engine includes a nozzle section, an expansion section, and an air entrainment section. The nozzle section is communicable in exhaust receiving communication with the internal combustion engine. The nozzle section includes a plurality of nozzles through which an exhaust gas stream is flowable. The expansion section is communicable in exhaust receiving communication with the plurality of nozzles. The air entrainment section is communicable in air supplying communication with the expansion section. The air is mixable with the exhaust gas within the expansion section.
1. An aspirator for cooling exhaust gas from an internal combustion engine, comprising:
a nozzle section communicable in exhaust receiving communication with the internal combustion engine, the nozzle section comprising a plurality of nozzles through which an exhaust gas stream is flowable, wherein the plurality of nozzles are positioned laterally adjacent each other, each nozzle comprising an exhaust inlet end and exhaust outlet end, and wherein the nozzle section further comprises a nozzle manifold defining an outer periphery, the plurality of nozzles being coupled to and extending from the nozzle manifold, and wherein the plurality of nozzles define a collective outer periphery encompassing the plurality of nozzles, the collective outer periphery of the plurality of nozzles at the exhaust outlet end being smaller than the outer periphery of the nozzle manifold;
an expansion section communicable in exhaust receiving communication with the plurality of nozzles, the expansion section comprising an expansion tube having an exhaust inlet end and an exhaust outlet end;
a housing tube within which the nozzle section and expansion section are positioned; and
an air entrainment section communicable in air supplying communication with the expansion section, the air being mixable with the exhaust gas within the expansion section, wherein the air entrainment section comprises a plurality of apertures formed in the housing tube;
wherein the exhaust inlet end of the expansion tube is positioned downstream of the exhaust outlet ends of the plurality of nozzles such that an axial space is defined between the exhaust inlet end of the expansion tube and the exhaust outlet ends of the plurality of nozzles.
2. The aspirator of claim 1 , wherein each of the plurality of nozzles comprises a converging portion in a direction of exhaust gas flow.
3. The aspirator of claim 1 , wherein the plurality of nozzles comprises at least four nozzles.
4. The aspirator of claim 1 , wherein the nozzles are similarly shaped.
5. The aspirator of claim 1 , wherein at least one of the plurality of nozzles defines a cross-sectional area having a first shape and at least one of the plurality of nozzles defines a cross-sectional area having a second shape, the first shape being different than the second shape.
6. The aspirator of claim 1 , wherein each of the plurality of nozzles defines a cross-sectional area having a substantially circular shape.
7. The aspirator of claim 1 , wherein each of the plurality of nozzles defines a cross-sectional area having a substantially conical frustum shape.
8. The aspirator of claim 1 , wherein each of the plurality of nozzles defines a cross-sectional area having a substantially bean shape.
9. The aspirator of claim 1 , wherein each of the plurality of nozzles defines a cross-sectional area having a substantially triangular shape.
10. The aspirator of claim 1 , wherein the air entrainment section comprises a plurality of apertures exposed to ambient air, the air entrainment section at least partially surrounding the plurality of nozzles and expansion section.
11. An engine exhaust system, comprising:
an exhaust pipe in exhaust receiving communication with an internal combustion engine;
an exhaust treatment device in exhaust receiving communication with the exhaust pipe;
an aspirator in exhaust receiving communication with the exhaust treatment device, the aspirator comprising:
a housing comprising an elongate tube;
a nozzle section communicable in exhaust receiving communication with the internal combustion engine, the nozzle section comprising a plurality of nozzles in parallel within the housing, the plurality of nozzles being positioned within the housing laterally adjacent each other, each nozzle comprising an inlet end and an outlet end, each nozzle being positioned about a central hub that is coaxial with the elongate tube, wherein exhaust gas is not flowable through the central hub, and wherein the nozzle section further comprises a nozzle manifold defining an outer periphery, the plurality of nozzles being coupled to and extending from the nozzle manifold, and wherein the plurality of nozzles define a collective outer periphery encompassing the plurality of nozzles, the collective outer periphery of the plurality of nozzles at the exhaust outlet end being smaller than the outer periphery of the nozzle manifold;
an expansion tube positioned coaxially within the elongate tube, the expansion tube comprising an inlet end and an outlet end, wherein the expansion tube is positioned relative to the plurality of nozzles such that the inlet end of the expansion tube is positioned downstream of the outlet ends of the plurality of nozzles and a space having an axial length is defined between the inlet end of the expansion tube and the outlet ends of the plurality of nozzles; and
an air entrainment system formed in the housing and configured to introduce air into exhaust flowing through the aspirator; and
a tailpipe in exhaust receiving communication with an outlet of the aspirator.
12. The engine exhaust system of claim 11 , wherein:
the exhaust treatment device comprises a particulate matter filter capable of experiencing an active regeneration; and
during active regeneration, a maximum exhaust temperature to average exhaust temperature ratio at the aspirator outlet is between about 1.0 and about 1.25.
13. The engine exhaust system of claim 11 , wherein:
the exhaust treatment device comprises a particulate matter filter capable of experiencing a stationary regeneration; and
during stationary regeneration, a maximum exhaust temperature to average exhaust temperature ratio at the aspirator outlet is between about 1.0 and about 1.25.
14. The engine exhaust system of claim 11 , wherein the plurality of nozzles are configured to increase a temperature uniformity of exhaust entering the tailpipe by increasing an exhaust/air mixing efficiency of the aspirator.
15. An aspirator for cooling exhaust gas from an internal combustion engine, comprising:
a nozzle section communicable in exhaust receiving communication with the internal combustion engine, the nozzle section comprising a plurality of nozzles through which an exhaust gas stream is flowable, wherein the plurality of nozzles are positioned laterally adjacent each other, each nozzle comprising an exhaust inlet end and exhaust outlet end, wherein each of the plurality of nozzles comprises a cross-sectional shape entirely bounded by two radii of a circle and an arc of the circle between the radii, and wherein the nozzle section further comprises a nozzle manifold defining an outer periphery, the plurality of nozzles being coupled to and extending from the nozzle manifold, and wherein the plurality of nozzles define a collective outer periphery encompassing the plurality of nozzles, the collective outer periphery of the plurality of nozzles at the exhaust outlet end being smaller than the outer periphery of the nozzle manifold;
an expansion section communicable in exhaust receiving communication with the plurality of nozzles, the expansion section comprising an expansion tube having an exhaust inlet end and an exhaust outlet end;
a housing tube within which the nozzle section and expansion section are positioned; and
an air entrainment section communicable in air supplying communication with the expansion section, the air being mixable with the exhaust gas within the expansion section, wherein the air entrainment section comprises a plurality of apertures formed in the housing tube;
wherein the exhaust inlet end of the expansion tube is positioned downstream of the exhaust outlet ends of the plurality of nozzles such that an axial space is defined between the exhaust inlet end of the expansion tube and the exhaust outlet ends of the plurality of nozzles.
16. The aspirator of claim 15 , wherein a curved surface defined by the arc of the circle between the radii of each of the plurality of nozzles converges toward a central axis of the nozzle section in an exhaust flow direction.
17. The aspirator of claim 16 , wherein the flat surfaces defined by the two radii of the circle of each of the plurality of nozzles remain at a constant distance away from the central axis of the nozzle section in the exhaust flow direction.