INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To cool recirculating exhaust gas to the desired temperature while simultaneously preventing discharge of soot and NOx even with a water-cooled cooler of a low capacity and to supply the recirculating exhaust gas of stable temperature into a combustion chamber. SOLUTION: Low-temperature combustion where the amount of EGR gas to be supplied into a combustion chamber 5 is more than the EGR gas amount with the peak generation of soot and thus generates almost no soot can be performed, and an air-cooled EGR cooler 1032 and a water-cooled EGR cooler 32 are arranged in an EGR passage 29 for connecting an engine exhaust passage to an engine intake passage. EGR gas flowing in the EGR passage 29 is cooled by the air-cooled EGR cooler 1032 and then cooled by the water-cooled EGR cooler 32 having the cooling water temperature more stable than the outside air temperature.