| 摘要 |
PURPOSE:To improve an air utilization factor by providing a pair of side cavity parts dented in a recessed shape toward the top surface of a piston and communicated on both sides of a diffusion bed with respective large cavity parts, and a bottom by which the side cavity parts are partitioned and which is gradually deepened from each trench part toward a region right below an injection nozzle. CONSTITUTION:Since a bottom 24 is inclined so that a side cavity part 14 is most deepened right below an injection nozzle 6, when a piston 3 is located in the vicinity of a top dead center of compression and the volume of a main combustion chamber 9 is reduced, a flow passage sectional area is ensured between the piston and the opening part on the main combustion chamber 9 side of the injection nozzle 6 and gas containing large quantity of fuel rapidly flows out from a vortex chamber 5 to the main combustion chamber 9. Further, in a jet injected in the main combustion chamber 9 through the injection nozzle 6, a force of a flow through a trench part 15 toward an opposite wall part 17A as it bypasses a diffusion bed 13 is increased. This constitution sufficiently improves an air utilization factor in the main combustion chamber, improves fuel consumption and an output, and reduces smoke density during high load operation.
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