JPS6319544Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of the combustion chamber of a diesel engine equipped with a swirl chamber (vortex type combustion chamber).

A diesel engine with a vortex chamber has a main chamber (main combustion chamber) formed at the top of the piston and a vortex chamber located in the cylinder head, and the two are connected at the throat of the vortex chamber. There is. The air sucked into the cylinder during the intake stroke is forced into the vortex chamber from the main chamber through the throat portion during the compression stroke, and fuel is injected into the vortex chamber at the end of the compression stroke. As a result, the air-fuel mixture formed in the vortex chamber ignites and combustion begins, and the combustion gas in the vortex chamber is ejected into the main chamber through the throat section, where it mixes with the air in the main chamber and is further combusted. It is completed.

As shown in FIGS. 1 and 2, the combustion chamber structure based on this combustion principle is such that the main chamber 1 is a clover-shaped recess that extends from near the edge of the piston 2 toward the center of the piston. Those formed are widely used.

As is clear from the figure, this main chamber 1 has two circular parts 11a and 11b corresponding to clover leaves.
The air is ejected through the throat part 51 of the vortex chamber 5, which has a diffusion part 11 consisting of a crowbar and a trench part 12 corresponding to a clover pod, and which generates an air vortex inside the cylinder head 4 side. The combustion gas flows into the diffusion section 11 from the trench section 12, changes its course by the circular deflection wall 13 of the diffusion section 11, and diffuses to the outside while forming a swirling flow.
It is configured to be mixed with the air in the cylinder and combusted.

In FIG. 1, 6 indicates a cylinder body, 7 indicates a fuel injection nozzle, and 8 indicates a glow plug. However, in such a combustion chamber structure, when the width of the throat portion 51 is increased, the output at high loads increases and the generation rate of Nox (N) in the vortex chamber 5 decreases as shown in FIG. 3. On the other hand, there is a problem that the generation rate of smoke (S) increases, and the width of the throat portion 51 must be made smaller than the ideal value for increasing output and reducing Nox under high loads. There were flaws.

This project was devised to overcome the above-mentioned drawbacks, and its purpose is to maintain the width of the throat portion of the vortex chamber at an ideal value in order to increase output and reduce NOx under high loads. It is an object of the present invention to provide a combustion chamber for a diesel engine with a vortex chamber that reduces smoke while reducing smoke, and an embodiment thereof will be described below with reference to the drawings.

As described above, the diffusion section 1 has two substantially circular circular sections 11a and 11b that expand and branch from the trench section 12 that communicates with the throat section 51 of the vortex chamber 5.
1 is formed on the top portion 3 of the piston 2 from near the edge toward its center, the width t of the trench portion 12 is greater than the width to of the throat portion 51 of the vortex chamber. It is made small.

In the combustion chamber configured as described above, the width of the throat portion 51 is made relatively large, so that output can be increased and Nox reduced during high loads, and the combustion gas B from the vortex chamber 5 can flow through the throat. The combustion gas in the main chamber 1 is ejected to the main chamber 1 side through the section 51, but because the width t of the trench section 12 is small, it is narrowed here and the flow velocity is increased and flows into the diffusion section 11. Since mixed combustion of the fuel and unburned air is promoted, the smoke generated during combustion in the vortex chamber 5 is almost eliminated during combustion in the main chamber 1.

Therefore, the overall engine output can be increased during high loads, and the harmful components of exhaust gas can be reduced.
It has the advantage of providing ideal combustion conditions with less Nox and smoke.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view showing the vicinity of the combustion chamber in this embodiment, Fig. 2 is a schematic plan view showing the relationship between the vortex chamber and the main chamber in the same embodiment, and Fig. 3 is a view of the throat section of the vortex chamber. FIG. 3 is a characteristic diagram showing exhaust characteristics. 1; Main chamber, 2; Piston, 5; Vortex chamber, 11; Diffusion part, 12; Trench part, 51; Throat part,
B; Combustion gas.

Claims (1)

[Scope of utility model registration request] A trench part communicating with the throat part of the vortex chamber and a diffusion part having two substantially circular parts expanding and branching from the trench part are formed at the top part from near the edge of the piston toward the center thereof. 1. A combustion chamber for a diesel engine with a swirl chamber, characterized in that the width t of the trench portion is smaller than the width to of the throat portion of the swirl chamber.