Two-cycle engine resonance exhaust system

Claim 2

In a chain saw engine exhaust system, said engine having an exhaust port, the improvement comprising a resonant chamber exhaust for said chain saw engine leading from the exhaust port on the engine including a tubular member having an inlet and an outlet and a first diverging section generally expanding in cross sectional area to a cross sectional area greater than the area of said exhaust port, a positive exhaust gas pressure wave reflecting surface in said tubular member between said first diverging section and the outlet of said tubular member, means positioning said positive exhaust gas pressure wave reflecting surface so as to reflect the principal exhaust gas pressure wave back to said exhaust port for arrival at said exhaust port shortly prior to closing of said exhaust port when the engine revolution per minute is in a desired range, said tubular member being bent into a shape so the outer peripheral dimensions thereof are not substantially greater than the outer peripheral dimensions of the main body of said chain saw, and an engine exhaust silencing means substantially within the confines of the periphery of the bent tubular member and open to the outlet of the tubular member.

Claim 3

The combination as specified in claim 1 wherein said tubular member is formed at least partially with substantially coextensive top and bottom walls, and divider walls forming the diverging section and the wave reflecting surface between said top and bottom walls, one of said top and bottom walls being substantially contiguous with the chain saw.

Claim 4

The combination as specified in claim 1 wherein said tubular member is formed at least partially into the engine portion of said chain saw.

Claim 5

The combination as specified in claim 1 wherein said positive wave reflecting surface is formed by a generally converging surface between an outer end of said diverging section and the outlet from said tubular member.

Claim 6

The combination as specified in claim 1 wherein said tubular member is formed at least partially with generally coextensive spaced apart first and second walls, and divider walls forming the diverging section and the wave reflecting surface extending between said first and second walls, one of said first and second walls being substantially contiguous with the chain saw.

Claim 7

The combination as specified in claim 1 wherein said tubular member is bent generally into a U shape forming a pair of legs, said engine exhaust silencing means being positioned between the legs of the U shaped tubular member.

Claim 8

The combination as specified in claim 1 wherein there is provided a die cast exhaust housing which includes said tubular member and silencing sections and which has substantially parallel spaced apart main walls, divider walls extending between said main walls, and means removably fastening one of the main walls to the remainder of said housing.

Claim 9

The combination as specified in claim 7 wherein said divider walls are positioned relative to each other so that the tubular member has a curved portion and two end portions formed in the general shape of a U, said curved portion being part of the first diverging section of said tubular member.

Claim 10

In a two-cycle internal combustion engine having a power cylinder and exhaust port, the improvement comprising an exhaust system including a tubular member comprising walls forming a chamber having an inlet and an outlet, and including a first section generally expanding in cross sectional area in direction away from said exhaust port, a second section open to the first section and the outlet, said outlet being of reduced area as compared with the maximum cross sectional area of said first section, said second section forming a positive exhaust gas pressure wave reflecting surface, means positioning said second section so as to reflect the principal positive exhaust gas pressure wave back to the engine exhaust port for arrival at said exhaust port shortly prior to closing of said exhaust port when the engine revolutions per minute are in a desired range, said tubular member having at least one bend along its length to form a shape for said tubular member other than linear, said tubular member walls thereby having peripheral surface portions which at least partially define a space other than said chamber, and means defining an exhaust silencing section separate from said chamber confined substantially within the space defined by the peripheral surface portions of said tubular member, the outlet of said chamber opening to said silencing section, and said silencing section having exhaust gas discharge means.

Claim 11

In a two-cycle internal combustion engine having a power cylinder and exhaust port, the improvement comprising an exhaust system including a tubular member comprising walls forming a chamber having an inlet and an outlet, and including a first section generally expanding in cross sectional area in direction away from said exhaust port, a second section open to the first section and the outlet, said outlet being of reduced area as compared with the maximum cross sectional area of said first section, said second section forming a positive exhaust gas pressure wave reflecting surface, means positioning said second section so as to reflect the principal positive exhaust gas pressure wave back to the engine exhaust port for arrival at said exhaust port shortly prior to closing of said exhaust port when the engine revolutions per minute are in a desired range, said tubular member having at least one bend along its length to form a shape for said tubular member other than linear, said tubular member walls thereby having peripheral surface portions which at least partially define a space other than said chamber, and means defining an exhaust silencing section separate from said chamber confined substantially within the space defined by the peripheral surface portions of said tubular member, the outlet of said chamber opening to said silencing section, and said silencing section having exhaust gas discharge means.

Claim 12

The combination as specified in claim 9 wherein said generally expanding cross section of said expansion chamber expands to a cross sectional area greater than the cross sectional area of the exhaust port of said internal combustion engine.

Claim 13

The combination as specified in claim 9 wherein said tubular member has first and second walls which have general planes that extend parallel for at least portions thereof, ad divider walls extending between said first and second walls forming the first, second and silencing sections, and removable means fastening the first wall for said tubular member to a main portion thereof.

Claim 14

The combination as specified in claim 9 wherein the central axis of said tubular member changes direction at an included angle of at least 90* so that portions of the walls of the tubular member face generally toward each other, at least a portion of said silencing section being positioned between the portions of the walls of said tubular member that face generally toward each other.

Claim 15

The combination as specified in claim 12 wherein said silencing section is generally cylindrical, said tubular member being of length to wrap at least partially around said silencing section.

Claim 16

The combination as specified in claim 12 wherein said internal combustion engine has a plurality of power cylinders each with an exhaust port, a separate tubular member leading from the exhaust port for each cylinder, said silencing section being a generally cylindrical member, said separate tubular members being wrapped at least partially around said generally cylindrical member and each opening to said generally cylindrical silencing section.

Claim 17

In a two-cycle internal combustion engine having a power cylinder and an exhaust port, the improvement comprising an exhaust system including a tubular member having walls forming an exhaust chamber having an inlet and an outlet, and including a first section generally expanding in cross sectional area in direction away from said exhaust port, a second section open to the first section and the outlet, said second section including means forming a positive exhaust gas wave reflecting surface so positioned as to reflect the principal positive exhaust gas pressure wave back to the engine exhaust port and arriving at said exhaust port shortly prior to closing of said exhaust port when the engine revolutions per minute are in a desired range, the central axis of said tubular member changing direction at least once to form a shape for said tubular member other than linear, and an exhaust silencing section confined substantially within the extremities of the peripheral dimensions of said tubular member, the outlet of said exhaust chamber opening to said silencing section, said silencing section comprising a closed silencing chamber, a first passageway means leading from said second section and being open to said silencing chamber, said first passageway means being blocked at the end thereof in said silencing chamber and having perforations therethrough positioned in said silencing chamber, and an exhaust gas outlet pipe open to said silencing chamber and the exterior of said exhaust system, said outlet pipe having the end thereof blocked on the interior of said silencing chamber and being provided with perforations through a side wall thereof.

Claim 18

In a two-cycle internal combustion engine having a power cylinder and an exhaust port, the improvement comprising an exhaust system including a tubular member having walls forming an exhaust chamber having an inlet and an outlet, and including a first section generally expanding in cross sectional area in direction away from said exhaust port, a second section open to the first section and the outlet, said second section including means forming a positive exhaust gas wave reflecting surface so positioned as to reflect the principal positive exhaust gas pressure wave back to the engine exhaust port and arriving at said exhaust port shortly prior to closing of said exhaust port when the engine revolutions per minute are in a desired range, the central axis of said tubular member changing direction at least once to form a shape for said tubular member other than linear, and an exhaust silencing section confined substantially within the extremities of the peripheral dimensions of said tubular member, the outlet of said exhaust chamber opening to said silencing section, said silencing section comprising a closed silencing chamber, a first passageway means leading from said second section and being open to said silencing chamber, said first passageway means being blocked at the end thereof in said silencing chamber and having perforations therethrough positioned in said silencing chamber, and an exhaust gas outlet pipe open to said silencing chamber and the exterior of said exhaust system, said outlet pipe having the end thereof blocked on the interior of said silencing chamber and being provided with perforations through a side wall thereof.

Claim 19

In a two-cycle internal combustion engine having a power cylinder and an exhaust port, the imprOvement comprising an exhaust system including a tubular member having walls forming a chamber having an inlet and an outlet, and including a first section generally expanding in cross sectional area in direction away from said exhaust port, a second section open to the first section and the outlet, said second section including means forming a positive exhaust gas wave reflecting surface so positioned as to reflect the principal positive exhaust gas pressure wave back to the engine exhaust port and arriving at said exhaust port shortly prior to closing of said exhaust port when the engine revolutions per minute are in a desired range, the central axis of said tubular member being bent substantially into a U shape with the bend portion of said tubular member in a generally expanding portion of said chamber, and an exhaust silencing section confined substantially within the extremities of the peripheral dimensions of said bent tubular member, the outlet of said chamber opening to said silencing section, and exhaust gas discharge means from said silencing section.

Claim 20

In a two-cycle internal combustion engine having a power cylinder and an exhaust port, the imprOvement comprising an exhaust system including a tubular member having walls forming a chamber having an inlet and an outlet, and including a first section generally expanding in cross sectional area in direction away from said exhaust port, a second section open to the first section and the outlet, said second section including means forming a positive exhaust gas wave reflecting surface so positioned as to reflect the principal positive exhaust gas pressure wave back to the engine exhaust port and arriving at said exhaust port shortly prior to closing of said exhaust port when the engine revolutions per minute are in a desired range, the central axis of said tubular member being bent substantially into a U shape with the bend portion of said tubular member in a generally expanding portion of said chamber, and an exhaust silencing section confined substantially within the extremities of the peripheral dimensions of said bent tubular member, the outlet of said chamber opening to said silencing section, and exhaust gas discharge means from said silencing section.

Claim 21

In a two-cycle internal combustion engine having a power cylinder and an exhaust port, the improvement comprising an exhaust system including a tubular member having walls forming a chamber having an inlet and an outlet, and including a first section generally expanding in cross sectional area in direction away from said exhaust port, a second section open to the first section and the outlet, said second section including means forming a positive exhaust gas wave reflecting surface so positioned as to reflect the principal positive exhaust gas pressure wave back to the engine exhaust port and arriving at said exhaust port shortly prior to closing of said exhaust port when the engine revolutions per minute are in a desired range, said tubular member being formed into a generally U shaped member, and an exhaust silencing section positioned between the facing walls of said tubular member forming the U, the outlet of said chamber opening to said silencing section, and exhaust gas discharge means from said silencing section.

Claim 22

In a two-cycle internal combustion engine having a power cylinder and an exhaust port, the improvement comprising an exhaust system including a tubular member having walls forming a chamber having an inlet and an outlet, and including a first section generally expanding in cross sectional area in direction away from said exhaust port, a second section open to the first section and the outlet, said second section including means forming a positive exhaust gas wave reflecting surface so positioned as to reflect the principal positive exhaust gas pressure wave back to the engine exhaust port and arriving at said exhaust port shortly prior to closing of said exhaust port when the engine revolutions per minute are in a desired range, said tubular member being formed into a generally U shaped member, and an exhaust silencing section positioned between the facing walls of said tubular member forming the U, the outlet of said chamber opening to said silencing section, and exhaust gas discharge means from said silencing section.

Claim 23

The combination as specified in claim 17 wherein said tubular member and said silencing section are spaced, and wall means defining fluid passageways between portions of said tubular member and said silencing section.

Claim 24

The combination of claim 17 further characterized in that the tubular member is made from sections of formed sheet metal, said silencing section being spaced from the walls forming the tubular member and substantially planar wall means joining the walls of said tubular member and said silencing section.

Claim 25

In a two-cycle internal combustion engine having a power cylinder and an exhaust port, the improvement comprising an exhaust system including a tubular member having walls forming a chamber having an inlet and an outlet, and including a first section generally expanding in cross sectional area in direction away from said exhaust port, a second section open to the first section and the outlet, said second section including generally converging surface means located between an outer end of said first section and the outlet from said chamber and forming a positive exhaust gas wave reflecting surface so positioned as to reflect the principal positive exhaust gas pressure wave to arrive back at the engine exhaust shortly prior to closing of said exhaust port when the engine revolutions per minute are in a desired range, the central axis of said tubular member changing direction at least once to form a shape for said tubular member other than linear, and an exhaust silencing section confined substantially within the extremities of the peripheral dimensions of said tubular member, the outlet of said chamber opening to said silencing section, and exhaust gas discharge means from said silencing section.

Claim 26

In a two-cycle internal combustion engine having a power cylinder and an exhaust port, the improvement comprising an exhaust system including a tubular member having walls forming a chamber having an inlet and an outlet, and including a first section generally expanding in cross sectional area in direction away from said exhaust port, a second section open to the first section and the outlet, said second section including generally converging surface means located between an outer end of said first section and the outlet from said chamber and forming a positive exhaust gas wave reflecting surface so positioned as to reflect the principal positive exhaust gas pressure wave to arrive back at the engine exhaust shortly prior to closing of said exhaust port when the engine revolutions per minute are in a desired range, the central axis of said tubular member changing direction at least once to form a shape for said tubular member other than linear, and an exhaust silencing section confined substantially within the extremities of the peripheral dimensions of said tubular member, the outlet of said chamber opening to said silencing section, and exhaust gas discharge means from said silencing section.

Claim 27

In a two-cycle internal combustion engine having a power cylinder and an exhaust port, the improvement comprising an exhaust system including A tubular member having walls forming a chamber having an inlet and an outlet, and including a first section generally expanding in cross sectional area in direction away from said exhaust port, a second section open to the first section and the outlet, said second section including means forming a positive exhaust gas wave reflecting surface so positioned as to reflect the principal positive exhaust gas pressure wave back to the engine exhaust port and arriving at said exhaust port shortly prior to closing of said exhaust port when the engine revolutions per minute are in a desired range, said tubular member including first and second wall means that overlie each other and are generally coextensive, and divider wall means extending between said first and second wall means, said wall means forming the first section and the wave reflecting surface, the central axis of said tubular member changing direction at least once to form a shape for said tubular member other than linear, and an exhaust silencing section confined substantially within the extremities of the peripheral dimensions of said tubular member, the outlet of said chamber opening to said silencing section, and said silencing section having exhaust gas discharge means.

Claim 28

In a two-cycle internal combustion engine having a power cylinder and an exhaust port, the improvement comprising an exhaust system including A tubular member having walls forming a chamber having an inlet and an outlet, and including a first section generally expanding in cross sectional area in direction away from said exhaust port, a second section open to the first section and the outlet, said second section including means forming a positive exhaust gas wave reflecting surface so positioned as to reflect the principal positive exhaust gas pressure wave back to the engine exhaust port and arriving at said exhaust port shortly prior to closing of said exhaust port when the engine revolutions per minute are in a desired range, said tubular member including first and second wall means that overlie each other and are generally coextensive, and divider wall means extending between said first and second wall means, said wall means forming the first section and the wave reflecting surface, the central axis of said tubular member changing direction at least once to form a shape for said tubular member other than linear, and an exhaust silencing section confined substantially within the extremities of the peripheral dimensions of said tubular member, the outlet of said chamber opening to said silencing section, and said silencing section having exhaust gas discharge means.

Claim 29

The device of claim 21 further characterized in that said tubular member is formed into two parts, said first wall means and said divider wall means being integrally formed together, and said second wall means being removably fastened with respect to said divider wall means.

Claim 30

Said device of claim 21 wherein said divider wall means are positioned relative to each other so that the tubular member is formed into the general shape of a U, and said exhaust silencing section is positioned between the divider wall means forming the facing sides of the legs of the U shaped tubular member.

Claim 31

The device of claim 21 wherein said divider wall means are of substantially smaller height than the width and length of said first and second wall means.