Structure of a main combustion chamber of a diesel engine of a direct injection type
This patent describes a structure of a main combustion chamber of a diesel engine of a direct injection type in which a main combustion chamber having a peripheral wall and a bottom wall is formed by a hollow at a top of a piston, above peripheral wall includes collision walls and guide walls which are disposed alternately to each other in a circumferential direction of the piston. A fuel injection nozzle having nozzle holes is disposed in or at the rear of the combustion chamber, the injection nozzle is designed to radiately spray the fuel only against the collision walls, and the sprayed collided fuel is adapted to flow along the guide walls in one direction while forming a swirl; characterized in that; each guide wall includes an upstream portion and a downstream portion with a boundary therebetween with respect to the direction of the swirl, a radial distance from the center of the chamber to the boundary is shorter than a radial distance from the center of the chamber to other portions and each upstream portion has a longer radius of curvature and a circumferential length than each downstream portion so that the inner periphery of the chamber has a pin-wheel-like shape. The upstream portions form smooth walls along which the fuel after collision flows while forming a film of the fuel. The downstream portions form walls along which the fuel flows from the boundaries, and the circumferential angle of each collision wall is so determined that the fuel sprayed from the nozzle holes collides only with the collision walls; each collision wall does not, in combination with the lower portion of a corresponding guiding wall, constitute a radial pocket operative to retain a mass of fuel, but comprises a lower portion wall forming a support surface contributing to the swirl in fuel flow.
- Assignee:
- Yanmar Diesel Engine Co., Ltd., Osaka
- Patent Number(s):
- US 4635597
- OSTI ID:
- 6816686
- Resource Relation:
- Patent File Date: Filed date 16 Jan 1985
- Country of Publication:
- United States
- Language:
- English
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