JP2521461Y2 - Internal combustion engine intake port - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake port of an internal combustion engine.

[0002]

Recently, in the internal combustion engine such as a diesel engine for use in an automobile, with the strengthening of exhaust gas regulations, delaying the ignition timing lowers the combustion temperature, although it is attempted to reduce the N0 _x, In this case, afterburning occurs and black smoke increases. Therefore, various measures have been taken to the intake port in order to improve the mixing of fuel and intake air as a countermeasure against this.

As an intake port designed to improve the mixing of this type of fuel and intake air, for example, the actual open port Sho 53-8730.
There is one such as that described in Japanese Patent Publication No. 9, which is a helical port 1 for making intake air into a swirl flow in the combustion chamber 3 as shown in FIGS. An intake port is constituted by a directional port 2 which is tangentially introduced so as to collide with and merge with the swirling flow.

[0004]

In the intake port of the internal combustion engine as described above, the swirl flow flowing from the helical port 1 into the combustion chamber 3 collides the intake air from the directional port 2 with each other. Sufficient strength was not obtained in terms of turbulence, and mixing of fuel and intake was insufficient, especially in the low and middle speed regions where the intake air flow rate was small, and the amount of black smoke was particularly high in the low and middle speed regions.

In view of the above situation, the present invention increases the turbulence intensity of intake air even in the low and medium speed regions where the intake air flow rate is small,
It is an object of the present invention to provide an intake port of an internal combustion engine capable of sufficiently mixing fuel and intake air and reducing NO _{x and} black smoke in exhaust gas.

[0006]

SUMMARY OF THE INVENTION The present invention comprises an inlet passage connected to an intake manifold, and a spiral passage extending continuously from the inlet passage and wound around the intake valve stem axis and leading to a combustion chamber. A stepped portion formed on an upper wall surface at a boundary portion between the inlet flow passage and the spiral flow passage so as to descend one step toward the combustion chamber, and leading a part of intake air to the combustion chamber as a separated flow; A helical port having a tongue portion projecting at the downstream end portion and introducing the intake air other than the separated flow into the combustion chamber as a swirl flow, and the intake air introduced from the intake manifold as a linear flow in a substantially tangential direction of the combustion chamber. And a directional port having a linear flow path having a protruding shroud portion for colliding with a swirl flow introduced into the combustion chamber along the tongue portion. is there

[0007]

Therefore, when the intake air sucked into the helical port flows into the spiral flow passage from the inlet flow passage, a part of the intake air is separated from the upper wall surface by the step portion and flows into the combustion chamber as a separated flow. Other than that, the intake air that has passed through the spiral flow passage from the inlet flow passage and flows into the combustion chamber along the tongue portion as a swirl flow, while the intake air sucked into the directional port is from the straight flow passage to the shroud portion. Flow into the combustion chamber as a linear flow, collide with the swirl flow, and merge into a combined flow with some turbulence. The combined flow becomes a large swirl flow along the peripheral surface of the combustion chamber. The separated flow collides with the separated flow and merges, resulting in stronger turbulence.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 4 show an embodiment of the present invention, which is an inlet passage 1a connected to an intake manifold (not shown).
And a spiral flow passage 1b which continuously extends from the inlet flow passage 1a and is wound around the axis of the intake valve stem 4 and communicates with the combustion chamber 3.
And a stepped portion 1d which is formed on the upper wall surface at the boundary between the inlet flow passage 1a and the spiral flow passage 1b so as to descend one step toward the combustion chamber 3 and guides a part of the intake air to the combustion chamber 3 as a separated flow 6. And a tongue portion 1c protruding from the downstream end of the spiral flow passage 1b to guide the intake air other than the separated flow 6 into the combustion chamber 3 as a spiral flow 7, and the intake air A shroud portion 2b for projecting intake air introduced from the manifold as a linear flow 8 in a substantially tangential direction of the combustion chamber 3 and colliding with a swirl flow 7 guided to the combustion chamber 3 along the tongue portion 1c is provided in a protruding manner. The directional port 2 having the linear flow path 2a is formed, and the helical port 1 and the directional port 2 constitute an intake port.

In the figure, reference numeral 5 is an intake valve stem provided in the directional port 2.

With the above-described structure, when the intake air sucked into the helical port 1 flows into the spiral flow passage 1b from the inlet flow passage 1a, a part thereof is separated from the upper wall surface by the step portion 1d. In addition to flowing into the combustion chamber 3 as the separated flow 6, the other flow passes through the spiral flow passage 1b from the inlet flow passage 1a and flows into the combustion chamber 3 along the tongue portion 1c as the spiral flow 7.

On the other hand, the intake air sucked into the directional port 2 flows into the combustion chamber 3 from the linear flow passage 2a along the shroud portion 2b as a linear flow 8, and the height position from the upper end of the combustion chamber 3 is changed. In a region within 0.5D (D is the inner diameter of the combustion chamber), the combined flow 9 collides with the swirl flow 7 and merges into a combined flow 9 with some turbulence.

The combined flow 9 is generated in the combustion chamber 3 in the region where the height position from the upper end of the combustion chamber 3 is 0.5D to 1.0D.
The separated flow 6, which is a large swirling flow along the inner peripheral surface, collides with and merges with each other to generate further turbulence.

In this way, since the collision of the intake air is carried out twice in the combustion chamber 3, the fuel and the intake air are sufficiently mixed even in the low and medium speed regions where the intake air flow rate is small, and the exhaust gas is exhausted. It is possible to reduce black smoke in addition to reducing NO _{x in the} inside.

Incidentally, the intake port of the internal combustion engine of the present invention is not limited to the above-mentioned embodiment, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

[0016]

As described above, according to the intake port of the internal combustion engine of the present invention, it is possible to cause the intake air to collide twice in the combustion chamber, and the low intake air flow rate in the low and medium speed range. Also in this case, the turbulence intensity of the intake air can be increased, the fuel and the intake air can be sufficiently mixed, and NO _{x and} black smoke in the exhaust gas can be reduced, which is an excellent effect.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of the present invention.

FIG. 2 is a side sectional view of a helical port according to an embodiment of the present invention.

FIG. 3 is a plan view showing an outline of intake air flow in an embodiment of the present invention.

FIG. 4 is a side view showing an outline of an intake air flow in one embodiment of the present invention (a view corresponding to an arrow IV-IV in FIG. 3).

FIG. 5 is a perspective view of a conventional example.

FIG. 6 is a side sectional view of the conventional example shown in FIG.

[Explanation of symbols]

 1 Helical type port 1a Inlet flow channel 1b Spiral flow channel 1c Tongue section 1d Step section 2 Directional port 2a Linear flow channel 2b Shroud section 3 Combustion chamber 4 Intake valve stem 6 Separation flow 7 Swirling flow 8 Linear flow 9 Synthesis Flow

Claims (1)

(57) [Scope of utility model registration request] 1. An inlet passage connected to an intake manifold, a spiral passage extending continuously from the inlet passage and wound around an intake valve stem axis to reach a combustion chamber, and the inlet passage and the spiral passage. A stepped portion that is formed on the upper wall surface at the boundary with the flow channel so as to descend one step toward the combustion chamber and guides a part of the intake air as a separated flow to the combustion chamber; A helical port having a tongue portion for guiding intake air other than the separated flow into the combustion chamber as a swirl flow, and intake air introduced from the intake manifold is introduced as a linear flow in a substantially tangential direction of the combustion chamber and along the tongue portion. An intake port of an internal combustion engine, comprising: a directivity type port having a linear flow path in which a shroud portion is provided so as to collide with a spiral flow guided to a combustion chamber.