DIRECT INJECTION TYPE INTERNAL COMBUSTION ENGINE

摘要

PURPOSE:To decrease generation amount of NOx by devising the internal combustion engine so that a part of fuel spray is caught on a central projection part while injection pressure and injection rate are restrained low at an injection initial stage and to that a combustion field is kept at a very low temperature. CONSTITUTION:A central projection part 10 projected upward from a bottom wall 5a part is formed in the central part of a combustion chamber 5 of an upper end open type formed on the upper wall of a piston 1. Additionally, a high pressure injection rate control injection system is set to start injecting fuel slightly before a top dead center and to restrain injection rate and injection pressure low during an injection initial stage near the top dead center together. Furthermore, an intercooler 27 connected to a compressor unit 26 of a supercharger 24 is connected to a supply air manifold 21, and supercharged air is cooled down by an aftercooler 35 after it is recompressed by a compressor unit 31, and it is lowered down to 0 - 5 deg.C simultaneously while supply air pressure is lower by expanding it at an air turbine unit 32.