Exhaust apparatus of internal combustion engine

An exhaust gas apparatus of an internal combustion engine, provided with an exhaust gas pipe at the downstream side of an internal combustion engine in the exhaust gas direction of an exhaust gas flow, the exhaust gas pipe having an upstream opening end at one end portion thereof and connected with a sound deadening device at the upstream side in the exhaust gas direction of the exhaust gas flow, and a downstream opening end at the other end portion thereof for exhausting the exhaust gas flow to the atmosphere, the exhaust gas apparatus comprises;

• a valve body having a swing shaft connected with the exhaust gas pipe to perpendicularly extend with respect to the center axis of the exhaust gas pipe and to be positioned outwardly of the center axis of the exhaust gas pipe and spaced apart from the center axis of the exhaust gas pipe, the valve body being adapted to receive only the exhaust gas flow flowing in the exhaust gas pipe and to be swingable around the center axis of the swing shaft to allow the passage cross-sectional area of the exhaust gas pipe to be varied, and
• a throttle unit for throttling the passage cross-sectional area of the exhaust gas pipe to a predetermined passage cross-sectional area when the valve body receives the flow amount of the exhaust gas flow flowing in the exhaust gas pipe in response to the operation state of the internal combustion engine to be swung around the center axis of the swing shaft in the case of an air column resonance being generated in the exhaust gas pipe, in which
• the throttle unit is constituted by a projection portion projecting toward the center axis of the exhaust gas pipe from the inner peripheral lower portion of the exhaust gas pipe, the initial position of the valve body being set to be inclined toward the upstream side of the exhaust gas direction of the exhaust gas flow,
• the projection portion being brought into face-to-face relationship with the lower end portion of the valve body to throttle the passage cross-sectional area of the exhaust gas pipe to the predetermined passage cross-sectional area when the valve body is swung from the initial position toward the downstream side of the exhaust gas direction of the exhaust gas flow.

An exhaust gas apparatus of an internal combustion engine, provided with an exhaust gas pipe at the downstream side of an internal combustion engine in the exhaust gas direction of an exhaust gas flow, the exhaust gas pipe having an upstream opening end at one end portion thereof and connected with a sound deadening device at the upstream side in the exhaust gas direction of the exhaust gas flow, and a downstream opening end at the other end portion thereof for exhausting the exhaust gas flow to the atmosphere, the exhaust gas apparatus comprises;

• a valve body having a swing shaft connected with the exhaust gas pipe to perpendicularly extend with respect to the center axis of the exhaust gas pipe and to be positioned outwardly of the center axis of the exhaust gas pipe and spaced apart from the center axis of the exhaust gas pipe, the valve body being adapted to receive only the exhaust gas flow flowing in the exhaust gas pipe and to be swingable around the center axis of the swing shaft to allow the passage cross-sectional area of the exhaust gas pipe to be varied, and
• a throttle unit for throttling the passage cross-sectional area of the exhaust gas pipe to a predetermined passage cross-sectional area when the valve body receives the flow amount of the exhaust gas flow flowing in the exhaust gas pipe in response to the operation state of the internal combustion engine to be swung around the center axis of the swing shaft in the case of an air column resonance being generated in the exhaust gas pipe, in which
• the throttle unit is partly constituted by a curved portion formed on the inner peripheral lower portion of the exhaust gas pipe to be curved along the swing locus of the lower portion of the valve body when the valve body is swung, the passage cross-sectional area of the exhaust gas pipe being throttled to the predetermined passage cross-sectional area by the curved portion when the valve body is in the predetermined swing range.