An EGR device includes an inlet portion into which EGR gas is introduced, a first outlet portion, a second outlet portion, and a passage portion. The first outlet portion and the second outlet portion each conduct, to the corresponding branch passage portion, the EGR gas that has been introduced through the inlet portion. The passage portion allows gas to flow between the inlet portion and the first outlet portion and between the inlet portion and the second outlet portion. The passage portion includes: a main passage that connects the inlet portion to the first outlet portion and to the second outlet portion; and an expansion chamber that is expanded outward from the main passage. The main passage includes a connecting portion. The connecting portion is connected to the second outlet portion and extends in a first direction. The expansion chamber is expanded outward from the connecting portion.

An exhaust gas recirculation (EGR) passage is connected with an intake passage (a bypass passage bypassing a supercharger) of an engine. The EGR passage includes, in a position close to a connection port to the intake passage, an expanding portion in which a passage cross-sectional area expands and which lowers a flow speed of EGR gas so as to reduce an uneven flow, in the connection port, of the EGR gas flowing into the intake passage.

An exhaust gas recirculation (EGR) passage is connected with an intake passage (a bypass passage bypassing a supercharger) of an engine. The EGR passage includes, in a position close to a connection port to the intake passage, an expanding portion in which a passage cross-sectional area expands and which lowers a flow speed of EGR gas so as to reduce an uneven flow, in the connection port, of the EGR gas flowing into the intake passage.

An EGR device includes an inlet portion into which EGR gas is introduced, a first outlet portion, a second outlet portion, and a passage portion. The first outlet portion and the second outlet portion each conduct, to the corresponding branch passage portion, the EGR gas that has been introduced through the inlet portion. The passage portion allows gas to flow between the inlet portion and the first outlet portion and between the inlet portion and the second outlet portion. The passage portion includes: a main passage that connects the inlet portion to the first outlet portion and to the second outlet portion; and an expansion chamber that is expanded outward from the main passage. The main passage includes a connecting portion. The connecting portion is connected to the second outlet portion and extends in a first direction. The expansion chamber is expanded outward from the connecting portion.

An EGR device includes an inlet portion into which EGR gas is introduced, a first outlet portion, a second outlet portion, and a passage portion. The first outlet portion and the second outlet portion each conduct, to the corresponding branch passage portion, the EGR gas that has been introduced through the inlet portion. The passage portion allows gas to flow between the inlet portion and the first outlet portion and between the inlet portion and the second outlet portion. The passage portion includes: a main passage that connects the inlet portion to the first outlet portion and to the second outlet portion; and an expansion chamber that is expanded outward from the main passage. The main passage includes a connecting portion. The connecting portion is connected to the second outlet portion and extends in a first direction. The expansion chamber is expanded outward from the connecting portion.

An EGR gas distributor for distributing EGR gas to branch pipes of an intake manifold includes a plurality of gas distribution passages arranged side by side for the branch pipes, a gas inflow passage and a gas chamber to deliver the EGR gas to each of the gas distribution passages. The gas inflow passage includes two, first and second, gas passage parts branched in a single stage. When the EGR gas distributor is mounted on the intake manifold, a passage cross-section of each gas passage part perpendicular to a central axis has an uppermost vertex and a lowermost vertex. The passage cross-sections of the gas passage parts are sized such that their lengths in a vertical direction are gradually longer from an upstream side of the first gas passage part to a downstream side of the second gas passage part.

An EGR gas distributor for distributing EGR gas to branch pipes of an intake manifold includes a plurality of gas distribution passages arranged side by side for the branch pipes, a gas inflow passage and a gas chamber to deliver the EGR gas to each of the gas distribution passages. The gas inflow passage includes two, first and second, gas passage parts branched in a single stage. When the EGR gas distributor is mounted on the intake manifold, a passage cross-section of each gas passage part perpendicular to a central axis has an uppermost vertex and a lowermost vertex. The passage cross-sections of the gas passage parts are sized such that their lengths in a vertical direction are gradually longer from an upstream side of the first gas passage part to a downstream side of the second gas passage part.

Provided is an intake manifold structure for an internal combustion engine including an intake manifold defining a plurality of branch passages (13) communicating with corresponding intake ports (6) of the internal combustion engine (1) arranged in a cylinder row direction thereof, and provided with additional gas introduction ports (29) communicating with the respective branch passages, and an additional gas introduction passage forming member (16) attached to the intake manifold, and defining an additional gas inlet (35) and additional gas introduction passages (14) communicating the additional gas inlet with the corresponding additional gas introduction ports, wherein the additional gas introduction passage forming member extends across the branch passages, and is provided with a guide wall (33) for defining the additional gas introduction passages in cooperation with an outer surface of the intake manifold and an inner surface of the additional gas introduction passage forming member.

Provided is an intake manifold structure for an internal combustion engine including an intake manifold defining a plurality of branch passages (13) communicating with corresponding intake ports (6) of the internal combustion engine (1) arranged in a cylinder row direction thereof, and provided with additional gas introduction ports (29) communicating with the respective branch passages, and an additional gas introduction passage forming member (16) attached to the intake manifold, and defining an additional gas inlet (35) and additional gas introduction passages (14) communicating the additional gas inlet with the corresponding additional gas introduction ports, wherein the additional gas introduction passage forming member extends across the branch passages, and is provided with a guide wall (33) for defining the additional gas introduction passages in cooperation with an outer surface of the intake manifold and an inner surface of the additional gas introduction passage forming member.

An exhaust gas recirculation (EGR) passage is connected with an intake passage (a bypass passage bypassing a supercharger) of an engine. The EGR passage includes, in a position close to a connection port to the intake passage, an expanding portion in which a passage cross-sectional area expands and which lowers a flow speed of EGR gas so as to reduce an uneven flow, in the connection port, of the EGR gas flowing into the intake passage.