Exhaust system for a two-cycle engine

Claim 2

An exhaust system for a two-cycle engine having at least one working chamber with an exhaust port fashioned into said working chamber comprising: a tubular member connected at one end in fluid communication with said exhaust port, and said tubular member including, an expansion section fashioned with an increasing crosssectional area from said one end of said tubular member for reducing pressure at said exhaust port of said at least one working chamber during an initial scavenging phase to aid in scavenging combusted fluid from said at least one working chamber, a generally U-shaped section fashioned with a constant crosssectional area and connected at one end to the other end of said expansion section to bend the flow of exhaust gas within said tubular member, and a contraction section fashioned with a decreasing crosssectional area connected at the large end thereof to the other end of said U-shaped section for reflecting pressure waves back through said tubular member to said exhaust port in said at least one working chamber to retard the flow of fluid from said at least one working chamber just prior to the closing of said at least one exhaust port whereby the retention of combustible fluid within the working chamber of said two-cycle engine may be optimized during a final scavenging phase to increase power output of said two-cycle engine; closure means sealing the other end of said contraction section to assist said contraction section in reflecting pressure waves back to said at least one exhaust port in said at least one working chamber; chamber means, encompassing said tubular member and dimensioned such that the interior of said chamber means is spaced from the exterior of said tubular member; means for supportingly connecting said tubular member within the interior of said chamber means; port means fashIoned through a wall of said tubular member for providing fluid communication between the interior of said tubular member and the interior of said chamber means; and an exhaust conduit connected into said chamber means for permitting exhaust gas to escape from said chamber means.

Claim 3

An exhaust system for a two-cycle engine as defined in claim 1 wherein said port means for providing fluid communication between the interior of said tubular member and the interior of said chamber means comprises: a tubular conduit tapped into the inner bight portion of said generally U-shaped section for providing fluid communication between the interior of said tubular member and said chamber means at a location within the tubular member of minimum pressure.

Claim 4

An exhaust system for a two-cycle engine as defined in claim 1 wherein: said chamber means is generally cylindrical and circular in cross-section.

Claim 5

An exhaust system for a two-cycle engine as defined in claim 1 wherein: said tubular member positioned within the interior of said chamber means has a resonant frequency variant from the resonant frequency of said chamber means whereby air pulsations within the interior of said chamber means may be attenuated.

Claim 6

An exhaust system for a two-cycle engine as defined in claim 1 wherein said chamber means comprises: a laminated wall structure including an outer layer of metallic material an intermediate layer of insulation material, and an inner layer of metallic material, said layers being juxtaposed to minimize heat transfer and attenuate fluid pulsations between the inner and outer layers of the walls.

Claim 7

An exhaust system for a two-cycle engine as defined in claim 1 wherein: said expansion section within the interior of said chamber means is provided with at least one 90* bend for providing a compact construction and fluid baffling structure to the interior of the chamber means.

Claim 8

An exhaust system for a two-cycle engine as defined in claim 6 wherein: said exhaust conduit is connected into said chamber means in a position whereby at least said expansion section is intermediate said exhaust conduit and said port means fashioned into said tubular member within said chamber means whereby air pulsations with exhaust gases which exit from said port means are attenuated by passing at least around the exterior of said expansion section prior to entering the exhaust conduit.

Claim 9

An exhaust system for a two-cycle engine having at least one working chamber with an exhaust port fashioned into said working chamber comprising: a tubular member connected at one end in fluid communication with said exhaust port and said tubular member including, an expansion section fashioned with an increasing cross-sectional area from said one end of said tubular member for reducing pressure at said exhaust port of said at least one working chamber during an initial scavenging phase to aid in scavenging combusted fluid from said at least one working chamber, a generally U-shaped section fashioned with a constant cross-sectional area downstream of said expansion section to bend in a generally opposite direction the flow of exhaust gas within said tubular member, and a contraction section fashioned with a decreasing cross-sectional area downstream of said generally U-shaped section for reflecting pressure waves back to said exhaust port in said at least one working chamber to retard the flow of fluid from said at least one working chamber just prior to the closing of said exhaust port whereby the retention of combustible fluid within the working chamber of said two-cycle engine may be optimized during a final scavenging phase; a closure sealing the other end of said tubular member to assist said contraction section in reflecting pressure waves back to said exhaust port in said at least one working chamber; a chamber positioned about and spaced from the exterior surface of said expansion section, said generallY U-shaped section and said contraction section; a tap-off conduit connected into the inner bight portion of said U-shaped section for providing fluid communication between the interior of said tubular member and the interior of said chamber for permitting exhaust gas to escape from said tubular member into the expanded volume of said chamber at a position of said tubular member of minimum pressure for minimizing pressure pulsations of the exhaust gases within said chamber; an exhaust conduit connected into said chamber at a position remote from said tap-off conduit; and means for supporting said tubular member within the interior of said chamber whereby fluid pulsations within exhaust gases entering said chamber from said tap-off conduit may be attenuated by being baffled around said expansion section, said U-shaped section, and said contraction sections prior to being exhausted from said chamber.

Claim 10

An exhaust system for a two-cycle engine having at least one working chamber with an exhaust port fashioned into said working chamber comprising: a tubular member connected at one end in fluid communication with said exhaust port and said tubular member including, an expansion section fashioned with an increasing cross-sectional area from said one end of said tubular member for reducing pressure at said exhaust port of said at least one working chamber during an initial scavenging phase to aid in scavenging combusted fluid from said at least one working chamber, a generally U-shaped section fashioned with a constant cross-sectional area downstream of said expansion section to bend in a generally opposite direction the flow of exhaust gas within said tubular member, and a contraction section fashioned with a decreasing cross-sectional area downstream of said generally U-shaped section for reflecting pressure waves back to said exhaust port in said at least one working chamber to retard the flow of fluid from said at least one working chamber just prior to the closing of said exhaust port whereby the retention of combustible fluid within the working chamber of said two-cycle engine may be optimized during a final scavenging phase; a closure sealing the other end of said tubular member to assist said contraction section in reflecting pressure waves back to said exhaust port in said at least one working chamber; a chamber positioned about and spaced from the exterior surface of said expansion section, said generallY U-shaped section and said contraction section; a tap-off conduit connected into the inner bight portion of said U-shaped section for providing fluid communication between the interior of said tubular member and the interior of said chamber for permitting exhaust gas to escape from said tubular member into the expanded volume of said chamber at a position of said tubular member of minimum pressure for minimizing pressure pulsations of the exhaust gases within said chamber; an exhaust conduit connected into said chamber at a position remote from said tap-off conduit; and means for supporting said tubular member within the interior of said chamber whereby fluid pulsations within exhaust gases entering said chamber from said tap-off conduit may be attenuated by being baffled around said expansion section, said U-shaped section, and said contraction sections prior to being exhausted from said chamber.

Claim 11

An exhaust system for a two-cycle engine as defined in claim 8 wherein: said expansion section is fashioned with at least one 90* bend and is positioned at least partially in front of the tap-off conduit of said tubular member.

Claim 12

An exhaust system for a two-cycle engine as defined in claim 8 wherein: said chamber is generally cylindrical and circular in cross section.

Claim 15

A method for facilitating the handling of exhaust gases from a two-cycle engine as defined in claim 11 wherein said tubular member is provided with at least one 90* bend in one portion thereof and at least one 180* bend in another portion thereof within the chamber, said step of baffling comprising: conducting exhaust gases, over and around the exterior surfaces of the tubular member within the chamber to break up and attenuate fluid pulsations within the exhaust gases.