| 摘要 |
PURPOSE:To enlarge the swirling range of a swirl as well as to uniformize the distribution of an air-fuel mixture by setting up a stepped part in an inner wall of a combustion chamber, and forming a collecting space for ignition fuel in the inner part of the combustion chamber, while recessing a protuberant wall of the stepped part to the wall side of the combustion chamber. CONSTITUTION:A square combustion chamber 2 is formed in a piston head 1. On the other hand, in a cylinder head 3, a fuel injection nozzle 5 is set up in a mounting hole 4 as adjoining the combustion chamber 2. And, this fuel injection nozzle 5 sprays sub-fuel spray F1 out of a sub-nozzle 9 at a low load area, while it sprays main fuel spray F2 out of a main nozzle 7 at a medium- high load area. In this constitution, a stepped part 14 is set up there in having it projected from a wall surface 2b of the combustion chamber 2, and thereby a collecting space D for collecting the sub-fuel spray F1 is formed there. And, a protuberant wall 14a being overhung toward the inward of the combustion chamber 2 at the stepped part 14 is bently formed as being recessed to the side of the wall surface 2b so as to expand an inner diameter of the combustion chamber 2 along a swirling path of the swirl S.
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