DIRECT INJECTION TYPE INTERNAL COMBUSTION ENGINE

摘要

PURPOSE:To decrease generation amount of NOx by devising the internal combustion engine in the title so that fuel spray collides against a tapered inner peripheral surface in a combustion chamber while injection pressure and injection rate are restrained low at an injection initial period and so that a combustion field is kept at a very high temperature. CONSTITUTION:A circular inner peripheral surface 7 of a combustion chamber 5 of upper edge open type formed on the upper wall of a piston 1 is formed in a tapered shape so that an upper edge part side is narrowed, and simultaneously, a central projection part 10 of a mushroom shape is formed in the central part of the combustion chamber 5. Additionally, the direction of a virtual central line A of fuel spray P injected from a plural number of injection ports of a top edge nozzle part of a fuel injection valve 3 fixed on a cylinder head 2 is set to be almost in parallel with the upper edge surface of the projection 10 and it is devised so that low pressure fuel spray P collides against the inner peripheral surface 7 at an injection initial stage. Additionally, a high pressure injection rate control injection system is set to restrain both injection rate and injection pressure low during the injection initial stage near a top dead center. A supercharger thereby cools fuel spray down to 1 - 5 deg.C by an intercooler 27 and a supply air cooling system 30 of a turbine type and thereafter supplies it to a supply air manifold.