Egr apparatus for internal combustion engine

An EGR apparatus for an internal combustion engine with a supercharger comprising:

• a mixing device provided in an intake passage for the internal combustion engine at an upstream side of a compressor of the supercharger for mixing EGR gas, which is a part of exhaust gas emitted from the internal combustion engine, with fresh intake air flowing through the intake passage and supplied into the mixing device,
• wherein the mixing device comprises;
• a first cylindrical member having an inlet portion for introducing the EGR gas into an inside of the first cylindrical member;
• a swirl flow generating portion for generating a swirl flow of the EGR gas introduced from the inlet portion into the inside of the first cylindrical member, so that the EGR gas spirally flows along an inner cylindrical wall of the first cylindrical member and flows in a downstream direction in the inside of the first cylindrical member;
• a second cylindrical member, a part of which is provided within the first cylindrical member so that the second cylindrical member is coaxially arranged with the first cylindrical member;
• a flow-in portion provided as a part of one of the first and the second cylindrical members and connected to the intake passage for introducing the fresh intake air into the second cylindrical member;
• a flow-out portion provided as a part of the second cylindrical member and partly provided in the inside of the first cylindrical member at a downstream side of the flow-in portion, so that the fresh intake air and the EGR gas for which the swirl flow is generated by the swirl flow generating portion flow into the flow-out portion;
• and
• an outlet portion formed in the first cylindrical member at a position away from the flow-out portion in an outward and radial direction and for discharging foreign material removed from the EGR gas through centrifugal separation out of the mixing device.

An EGR apparatus for an internal combustion engine with a supercharger comprising:

• a mixing device provided in an intake passage for the internal combustion engine at an upstream side of a compressor of the supercharger for mixing EGR gas, which is a part of exhaust gas emitted from the internal combustion engine, with fresh intake air flowing through the intake passage and supplied into the mixing device,
• wherein the mixing device comprises;
• a first cylindrical member having an inlet portion for introducing the EGR gas into an inside of the first cylindrical member;
• a second cylindrical member, a part of which is provided within the first cylindrical member so that the second cylindrical member is coaxially arranged with the first cylindrical member to form a double pipe structure;
• a flow-in portion provided as a part of the second cylindrical member and connected to the intake passage for introducing the fresh intake air into the second cylindrical member;
• a small-diameter portion provided as a part of the second cylindrical member, an inner diameter of the small-diameter portion being gradually decreased toward a downstream end thereof;
• and
• a flow-out portion provided as a part of the second cylindrical member and partly provided in the inside of the first cylindrical member, an inner diameter of an upstream end of the flow-out portion being equal to that of the downstream end of the small-diameter portion,
• the flow-out portion having an interflow portion so that the fresh intake air and the EGR gas flow into the flow-out portion,
• wherein the inlet portion is provided in the first cylindrical member at such a position, at which the inlet portion is offset from the interflow portion in an axial direction of the first cylindrical member, so that direct hitting of the EGR gas to the interflow portion is avoided.