Power tuned wave interference silencer

Claim 2

A silencer assembly for muffling noise and scavenging exhaust from an exhaust port of an engine comprising: an outer casing having an inlet end and an outlet end; a first open ended tube having one end located outside said casing and the other end thereof interiorly of said outer casing at the inlet end thereof to define a first outer flow path between said outer casing and said first tube, a second open ended tube having one end located outside said casing and the other end thereof directed interiorly of said outer casing at the outlet end thereof to define a second outer flow path between said outer casing and said second tube, said first and second tubes being located coaxially of one another and having open ends thereon located opposite one another in spaced relationship with respect to one another, said outer casing defining an open volume between said oppositely located open ends of said first and second tubes, a first wave interference helical baffle vane located within said first outer flow path having an inlet end and an outlet end in communication with said open volume, a second wave interference helical baffle vane located within said second outer flow path having an inlet end in communication with said open volume and an outlet end, means forming openings in said first tube communicating the interior of said tube with said first outer flow path at the inlet end of the first turn of said first helical baffle vane for producing a reflected wave from the open volume to the exhaust port of the engine, said first tube having a tuned length for producing a negative pressure at the exhaust port to reduce back pressure and to improve volumetric efficiency of the engine, said first interference helical baffle vane and said openings further serving to produce an interference wave for attenuating a first range of sound waves in said engine exhaust, said second tube having openings therein within said outer case in communication with the second outer flow path at the outlet end of said helical baffle vane to produce an interference wave to attenuate a second range of sound frequencies within said exhaust.

Claim 3

A silencer assembly comprising: an outer casing defining an interior volume, first wave interference means for directing exhaust into the interior volume of said outer casing, second wave interference means for directing exhaust from said interior volume of said outer casing, said first wave interference means including a first open ended inner tube with one end of said tube outside said casing and the other open end inside said casing and having a length to reflect an exhaust gas pressure pulse from the other open end of the first inner tube within the interior volume of the outer casing to the exhaust port of an engine to produce a negative pulse at the engine exhaust port for producing a scavenging effect, said second wave interference means including an open ended inner tube located coaxially of said first tube in spaced relationship therewith and defining an exhaust path from said outer casing, said first and second wave interference means each including a helical baffle defining a flow path located radially outwardly of each of said first and second tubes, said tubes and said outer flow paths being spaced apart from one another by an open volume within said interior volume of said outer casing, and holes within said first tube communicating with the inlet end of the outer path of said first wave interference silencer means to join with the open volume thereby to broaden the negative pulse at the exhaust port of an engine.

Claim 4

A silencer assembly comprising: an outer casing defining an interior volume, first wave interference means for directing exhaust into the interior volume of said outer casing, second wave interference means for directing exhaust from said interior volume of said outer casing, said first wave interference means including a first open ended inner tube with one end of said tube outside said casing and the other open end inside said casing and having a length to reflect an exhaust gas pressure pulse from the other open end of the first inner tube within the interior volume of the outer casing to the exhaust port of an engine to produce a negative pulse at the engine exhaust port for producing a scavenging effect, said second wave interference means including an open ended inner tube located coaxially of said first tube in spaced relationship therewith and defining an exhaust path from said outer casing, said first and second wave interference means each including a helical baffle defining a flow path located radially outwardly of each of said first and second tubes, said tubes and said outer flow paths being spaced apart from one another by an open volume within said interior volume of said outer casing, and holes within said first tube communicating with the inlet end of the outer path of said first wave interference silencer means to join with the open volume thereby to broaden the negative pulse at the exhaust port of an engine.

Claim 5

A power tuned silencer assembly comprising: an outer tubular casing having end closures to define a sealed interior volume, first wave interference means within one end of said volume including a first open ended tube with an inlet exterior of said casing and an outlet end located adjacent the midpoint of the interior volume of said outer casing, second wave interference means within said sealed volume including a second open ended tube located coaxially of said first tube and including an inlet end thereof located coaxially of the outlet end of said first tube in spaced relationship therewith within said outer casing and an outlet end exterior of said outer casing, said first tube having a length to produce a reflected wave from the interior volume to an engine exhaust port for producing a negative pulse at the engine exhaust port for scavenging an engine cylinder, said first wave interference means including means for attenuating a first range of sound frequencies in an engine exhaust, said second wave interference means including means for attenuating a second range of sound frequencies in the engine exhaust, said first interference means including a helical baffle on the exterior of said first tube to define an outer acoustical path open to said interior volume, said first tube having a plurality of openings at the inlet end thereof to intercommunicate said outer acoustical path and said sealed interior volume of said outer casing to broaden the negative pulse at the engine exhaust to improve scavenging of exhaust flow therefrom.

Claim 6

A power tuned silencer assembly comprising: an outer tubular casing having end closures to define a sealed interior volume, first wave interference means within one end of said volume including a first open ended tube with an inlet exterior of said casing and an outlet end located adjacent the midpoint of the interior volume of said outer casing, second wave interference means within said sealed volume including a second open ended tube located coaxially of said first tube and including an inlet end thereof located coaxially of the outlet end of said first tube in spaced relationship therewith within said outer casing and an outlet end exterior of said outer casing, said first tube having a length to produce a reflected wave from the interior volume to an engine exhaust port for producing a negative pulse at the engine exhaust port for scavenging an engine cylinder, said first wave interference means including means for attenuating a first range of sound frequencies in an engine exhaust, said second wave interference means including means for attenuating a second range of sound frequencies in the engine exhaust, said first interference means including a helical baffle on the exterior of said first tube to define an outer acoustical path open to said interior volume, said first tube having a plurality of openings at the inlet end thereof to intercommunicate said outer acoustical path and said sealed interior volume of said outer casing to broaden the negative pulse at the engine exhaust to improve scavenging of exhaust flow therefrom.

Claim 7

A power tuned silencer assembly comprising: an outer casing having closures on opposite ends thereof, a first open ended tube supported on one end of said outer casing centrally thereof, said first tube including an inlet end exterior of said casing adapted to be connected to the exhaust pipe of an engine and an outlet end located within the interior of said outer casing, a second tube supported on the opposite end of said outer casing including an inlet end located in spaced relationship to the outlet end of said first tube and including an outlet end adapted to be connected to a tailpipe, said outlet end of said first tube and the inlet end of said second tube having an open space volume therebetween within said outer casing, means forming a plurality of openings in said first tube immediately downstream of said inlet end thereof at a point within said outer casing, said openings having a cross-sectional flow area approximately equal to the cross-sectional flow area of said first tube, means defining a second plurality of openings in said second tube adjacent the opposite end wall of said outer casing having a cross-sectional flow area approximately equal to the cross-sectional flow area of said second tube, a first helical baffle connected between the outer surface of said first tube and the inner surface of said outer casing including an inlet end in communication with said first plurality of openings and an outlet end in communication with said open space volume, a second helical baffle wound on the outer surface of said second tube and connected between said second tube and the inner surface of said outer casing includiNg an inlet end in communication with said open space volume and an outlet end in communication with said second plurality of openings, said first tube having a length tuned to produce a reflected wave with a negative pulse at the exhaust port of an engine connected to the inlet end of said first tube for scavenging exhaust gases therefrom, said first plurality of holes communicating said outer path defined by said first baffle to join the in-between open space volume with said first tube interior at said openings to broaden the negative pulse of the reflected wave, said first tube and said first helical baffle in communication with said first plurality of openings further serving to attenuate a first range of sound frequencies in the engine exhaust, said second tube and said second wave interference baffle and said second plurality of openings serving to attenuate a second range of sound frequencies in the exhaust from the engine.

Claim 8

A power tuned silencer assembly comprising: an outer casing having closures on opposite ends thereof, a first open ended tube supported on one end of said outer casing centrally thereof, said first tube including an inlet end exterior of said casing adapted to be connected to the exhaust pipe of an engine and an outlet end located within the interior of said outer casing, a second tube supported on the opposite end of said outer casing including an inlet end located in spaced relationship to the outlet end of said first tube and including an outlet end adapted to be connected to a tailpipe, said outlet end of said first tube and the inlet end of said second tube having an open space volume therebetween within said outer casing, means forming a plurality of openings in said first tube immediately downstream of said inlet end thereof at a point within said outer casing, said openings having a cross-sectional flow area approximately equal to the cross-sectional flow area of said first tube, means defining a second plurality of openings in said second tube adjacent the opposite end wall of said outer casing having a cross-sectional flow area approximately equal to the cross-sectional flow area of said second tube, a first helical baffle connected between the outer surface of said first tube and the inner surface of said outer casing including an inlet end in communication with said first plurality of openings and an outlet end in communication with said open space volume, a second helical baffle wound on the outer surface of said second tube and connected between said second tube and the inner surface of said outer casing includiNg an inlet end in communication with said open space volume and an outlet end in communication with said second plurality of openings, said first tube having a length tuned to produce a reflected wave with a negative pulse at the exhaust port of an engine connected to the inlet end of said first tube for scavenging exhaust gases therefrom, said first plurality of holes communicating said outer path defined by said first baffle to join the in-between open space volume with said first tube interior at said openings to broaden the negative pulse of the reflected wave, said first tube and said first helical baffle in communication with said first plurality of openings further serving to attenuate a first range of sound frequencies in the engine exhaust, said second tube and said second wave interference baffle and said second plurality of openings serving to attenuate a second range of sound frequencies in the exhaust from the engine.