| 摘要 |
PROBLEM TO BE SOLVED: To enhance the distribution performance of EGR gas to cylinders in a engine having an intake system for distributing intake and supplying to the engine cylinders by means of branch passages branching from a collector. SOLUTION: An EGR gas introduction port 32 (32A, 32B) leading from an external recirculation passage is provided in an intake passage 23 upstream of a collector 24 so as to face in the tangential direction of the intake passage cross section. The plurality of EGR gas introduction ports 32 (32A, 32B) include a first introduction port 32A having a throttle passage part where the passage cross-sectional area decreases and a second introduction port 32B having no throttle passage part. EGR gas is injected at high speed into the intake passage by means of the throttle passage part of the first introduction port 32A to generate a strong spiral flow, this high-speed flow promoting the injection of the EGR gas from the second introduction port 32B. Thereby active airflow is generated in the intake passage whereby mixing of the EGR gas with fresh air can be promoted.
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