Exhaust gas purification device of internal combustion engine

An exhaust gas purification device of an internal combustion engine, comprising:

• an exhaust passage for guiding an exhaust gas discharged from the engine to outside;
• a catalyst provided in said exhaust passage;
• an injection path connected to an upstream side of said catalyst in said exhaust passage;
• an additive injection valve installed in said injection path and supplying an additive to said catalyst through the injection path;
• an inflow path for allowing a part of the exhaust gas flowing in said exhaust passage to enter said injection path;
• and
• a scavenging-flow forming means for forming the exhaust gas entering said injection path through said inflow path into a scavenging flow for cleaning the inside of the injection path,
• wherein said exhaust passage has a bent portion directing the exhaust gas flow toward the inlet of the catalyst,
• said injection path has a proximal end portion joined to said bent portion so that the injection path extends outward from the bent portion, and
• said inflow path is composed of an introduction pipe member connected to the injection path at an end and the exhaust passage at the other end to extend across a crotch area between the proximal end portion of the injection path and a curving portion of the exhaust passage immediately upstream of said proximal portion.

An exhaust gas purification device of an internal combustion engine, comprising:

• an exhaust passage for guiding an exhaust gas discharged from the engine to outside;
• a catalyst provided in said exhaust passage;
• an injection path connected to an upstream side of said catalyst in said exhaust passage;
• an additive injection valve installed in said injection path and supplying an additive to said catalyst through the injection path,
• said injection path including a pipe member separate from said exhaust passage, arranged to project into said exhaust passage, and
• said pipe member having a projecting end cut in a manner adapted to receive a part of the exhaust gas flowing in said exhaust passage, wherein
• the part of the exhaust gas entering from the exhaust passage through said cut end is formed into a scavenging flow arriving deep into the pipe member and cleaning the inside of the pipe member, and
• said cut end has a slit extending in a wall of the pipe member, parallel to the axis of the pipe member, where a part of the exhaust gas flowing in said exhaust passage enters the pipe member through the slit.