DIRECT COMBUSTION CHAMBER STRUCTURE FOR DIRECT INJECTION TYPE DIESEL ENGINE

摘要

PURPOSE:To accelerate a combustion speed and prevent any afterburning from occurring by forming a direct combustion chamber in a piston so as to be expanded in the radial direction toward the inmost recess from the central opening of a piston top face, while interconnecting the peripheral recess of the direct combustion chamber to a peripheral opening of the piston top face. CONSTITUTION:When a piston 16 goes up, volumetric capacity in a space at the more upper side than a piston top face 17 is decreased, and air at this upper side flows into a direct combustion chamber 22 by way of a center opening 24, a peripheral opening 28 and an interconnecting hole 30. At this time, this direct combustion chamber 22 is formed so as to have a large depth to the radial outside from the center opening 24, so that a large squish flow A is formed in the inner part. In addition, in and around a top dead center the piston 16, fuel is sprayed to a peripheral recess 26 of the direct combustion chamber 22 from a nozzle 20 as a spray. When the piston 16 further goes down, the volume in the more upper space than the piston top face 17 is increased, thus a flame in the direct combustion chamber 22 is jetted to the upper part of piston top face 17.