PROBLEM TO BE SOLVED: To reduce the dispersion of an EGR rate between cylinders by accelerating mixing with fresh air in the case of leading EGR gas from an EGR gas blowoff port into a collector.
SOLUTION: An EGR blowoff port 7 is formed of a cylindrical member 8 (8a, 8b), and a fresh air reservoir 12 communicated with the interior of a collector 4 is formed between the outer periphery of the cylindrical member 8 (8a, 8b) and base material (hole 9) of an intake manifold 2. The peripheral wall of the cylindrical member 8 is provided with a fresh air lead-in hole 13 opened to lead fresh air to the inside from the fresh air reservoir 12. EGR gas is therefore diffused rapidly in the collector 4 and equally distributed to each branch pipe so as to improve the dispersion of an EGR rate between cylinders. As a result, combustion stability is improved, exhaust emission is reduced, and fuel consumption is improved.
【課題】 コレクタ４内へのＥＧＲガス吹出し口７か ら、ＥＧＲガスを導入する場合に、新気との混合を促進 して、ＥＧＲ率の気筒間バラツキを低減する。
【解決手段】 ＥＧＲガス吹出し口７を筒状部材８によ り構成し、該筒状部材８の外周と吸気マニホールド２の 母材（穴９）との間にコレクタ４内と連なる新気溜まり １２を形成する。また、筒状部材８の周壁に新気溜まり １２から内部に新気を導入する新気導入孔１３を開設す る。