INTERNAL COMBUSTION ENGINE

PROBLEM TO BE SOLVED: To provide an internal combustion engine for securing an EGR gas function while improving the fuel efficiency by scavenging high-temperature exhaust gas residing in cylinders.SOLUTION: In an internal combustion engine, an intake port 10 is provided for each of cylinders 4, 5, 6. The intake ports 10 of the cylinders 4, 5, 6 and branch pipes 17-19 of an exhaust manifold 16 are connected to each other via EGR gas recirculation paths 22, 23, 24 in such a crisscrossed manner that they are shifted from each other in the array direction of the cylinders 4, 5, 6. High-pressure exhaust gas is reserved in the EGR gas recirculation paths 22, 23, 24 when one of the cylinders 4, 5, 6 is in an exhaust stroke, and then first injection of scavenging EGR gas to the cylinder adjacent thereto during an overlap period is followed by second injection of original EGR gas thereto after the overlap period. The high-temperature exhaust gas which is just burnt is scavenged to reduce the temperature of the exhaust gas in each of the cylinders. This enhances filling efficiency to improve fuel efficiency. 【課題】気筒に残留した高温の排気ガスを掃気して燃費の改善等を図りつつ、ＥＧＲガス機能も確保する。【解決手段】各気筒４，５，６毎に吸気ポート１０を設けた内燃機関において、気筒４，５，６の吸気ポート１０と排気マニホールド１６の枝管１７〜１９とが、ＥＧＲガス還流路２２，２３，２４により、気筒４，５，６の並び方向にずらしたタスキ掛け状態で接続されている。１つの気筒４，５，６が排気行程のときに高圧の排気ガスをＥＧＲガス還流路２２，２３，２４に溜めておいて、オーバーラップ期間中の隣の気筒に掃気用のＥＧＲガスを第１噴射し、次いで、オーバーラップ期間が経過してから本来のＥＧＲガスを第２噴射する。燃焼したての高温の排気ガスは掃気して、気筒内の排気ガスを温度が低下したもので構成できる。これにより、充填効率を高めて燃費を改善できる。【選択図】図１