JPS6024905Y2 - Intake vortex control device for direct injection diesel engine - Google Patents

Description

[Detailed description of the invention] The present invention relates to an intake vortex control device for a direct injection diesel engine, and more specifically, it changes the flow velocity of intake air by changing the flow path area of the intake port in accordance with the rotational speed of the engine. The present invention relates to an intake vortex control device for a direct injection diesel engine which is improved so as to stably change the swirl and eliminate variations in the swirl.

As an intake vortex control device for a direct injection type diesel engine, a device has been proposed in Japanese Patent Publication No. 7243/1983, which strengthens the swirl at low speed rotation and weakens the swirl as the speed increases.

This allows swirl to be generated more effectively over the entire rotational speed of the engine than in a normal engine, which is effective in preventing the generation of smoke and improving output.

However, the above control device changes the swirl by disposing a swirl control plate whose tip is a free end in the intake port and operating the control plate so that the port flow path area changes according to the rotation speed. Therefore, there is a problem particularly with the stability of the tip of the control plate, and it is not possible to obtain a swirl with high accuracy compared to the theoretical value, and there is a gap between the swirl control plate and the inner wall surface of the intake port. Therefore, there were problems such as not being able to obtain a specified swirl during low speed rotation, which is the most important time.

SUMMARY OF THE INVENTION Therefore, the present invention provides an intake vortex control device for a direct injection diesel engine that is improved by stabilizing the swirl control plate so that a swirl with high accuracy relative to the theoretical value can be obtained even at low speed rotation. With the goal.

In order to achieve the above object, the present invention provides a swirl control plate in the intake port that increases or decreases the flow path area of the intake flow according to the engine speed, and the control plate is arranged so that the end on the intake valve side is a free end. The main feature is that a stopper for the control plate is provided on the inner wall of the intake port.

Next, embodiments of the present invention will be described with reference to the drawings.

In FIGS. 1 to 4, an intake valve 2 in an intake port 1
A swirl forming section 3 is provided around the .

The swirl forming portion 3 has an inner wall formed in a spiral shape when viewed from above, and communicates with the rear portion of the intake port 1.

Further, at the rear of the swirl forming portion 3 in the intake port 1, a swirl control plate 5 whose one end is supported by a shaft 4 is arranged such that the tip thereof on the intake valve 2 side is a free end so as to be able to rotate in the vertical direction. It is arranged so that

This swirl control plate 5 detects the rotational speed of the engine by means such as vacuum force or centrifugal force, and is operated by rotating the shaft 4 based on this detected value, and the rotational speed of the engine is controlled by rotating the shaft 4 based on the detected value. When the rotational speed of the engine becomes small, the tip of the control plate 5 lowers to increase the intake flow path area in the intake port 1, and when the engine speed decreases, the tip of the control plate 5 rises to increase the intake air flow area in the intake port 1. It operates to reduce the flow path area.

As shown in FIG. 1, the swirl control plate 5 that operates in this manner is brought into contact with the lower inner wall of the intake port 1 when the intake flow path area in the intake port 1 is fully open, and the swirl control plate 5 is brought into contact with the lower inner wall of the intake port 1. The flow path area is not reduced.

Now, to explain the main part of the present invention, the left and right side walls of the intake port 1 are equipped with a A stopper or step 6 is provided to determine the position of the swirl control plate 5 when the intake flow path area becomes small.

Further, an elastic body 7 made of heat-resistant rubber or the like is attached to the upper surface of the swirl control plate 5 facing the step 6, and when the control plate 5 comes into contact with the step 6, these contact portions are In addition to sealing, elastic bodies 7 are provided on both left and right sides of the control plate 5.
By extending the elastic body 7, the elastic body 7 is always brought into contact with the left and right side walls of the intake port 1 as shown in FIG. ing.

Now, when the engine rotates at high speed, the swirl control plate 5
In the state shown in the figure, the intake flow path area is increased, but
At this time, since the intake air flow velocity is high, the swirl 8 is effectively formed in the swirl forming portion 3.

Also, when the engine is rotating at low speed, the swirl control plate 5
As shown in FIG. 2, this contacts the stepped portion 6 to reduce the area of the intake flow path.

At this time, the air suction force decreases, but the intake flow path area becomes smaller at the rear of the swirl forming portion 3, so if the intake air amount per unit time is kept constant, the intake flow rate becomes faster.

Therefore, a desired swirl 8 can be obtained in the swirl forming section 3.

At this time, the swirl control plate 5 is in contact with the stepped portion 6, so even if vibrations caused by the intake air flow or vibrations of the engine act on the control plate 5, the control plate 5 will not move up and down significantly like in the conventional device. It becomes stable without any problems.

Therefore, the formed swirl 8 is stable, so that the effect of improving output, exhaust smoke concentration, etc. can be increased.

Furthermore, by sealing the swirl control plate 5 and the left and right inner walls of the intake port 1 with the elastic body 7, even when the control plate 5 is located between the stepped portion 6 and the lower wall surface of the intake port 1, the elastic body 7 The self-excited vibration of the control plate 5 can be attenuated by contact with the left and right inner walls, and in this case as well, the control plate 5 can stably obtain the desired swirl 8.

Furthermore, since the contact portion between the swirl control plate 5 and the left and right inner walls of the intake port 1 is sealed, intake air does not leak from this contact portion.

Therefore, even when the swirl 8 changes as the control plate 5 moves up and down, a stable swirl is produced.

This is extremely effective especially at low speed rotations since the air suction force is weak.

As described above, according to the present invention, since the swirl control plate is stabilized, a highly accurate swirl can be obtained, and therefore, the effects of improving output, exhaust smoke concentration, etc. can be further enhanced.

In addition, since an elastic body is attached to the swirl control plate and the elastic body is brought into contact with the inner wall of the intake port, the control plate can be stabilized even when the swirl control plate is in the middle of movement. Since there is no leakage from the contact portion with the inner wall of the port, it is possible to obtain the effect of significantly strengthening the swirl, especially during low-speed rotation when the suction force is weak.

Note that the present invention has a swirl control plate 5a as shown in FIG.
is made of an elastic material, and when the base 4a is fixed, the control plate 5a is lowered by the resistance when the intake flow rate increases, and when the intake flow rate becomes slow, the step part 6 is lowered by the elastic force of the control plate 5a. This can also be applied to a device that rises until it touches the surface.

Furthermore, in this embodiment, the shape of the intake port 1 around the intake valve 2 is spirally shaped, which is a so-called helical port, but the present invention can also be applied to a so-called tangential port that gives directionality to the intake air and produces a swanil. Needless to say, the swirl control valve 5 can be applied to a valve that operates in the vertical direction of the intake port 1, but it can also be applied to one that operates in the horizontal direction to control the swirl.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a sectional view thereof, FIG. 2 is a sectional view showing the moving state of the swirl control plate, and FIG. 3 is a sectional view of FIG. 4 is a sectional view taken along line IV--IV in FIG. 1, and FIG. 5 is a sectional view showing another embodiment. 1...Intake port, 2...Intake valve, 5
, 5a... Swirl control plate, 6... Step portion (stopper), 7... Elastic body.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. A swirl control plate is provided in the intake port to increase or decrease the flow path area of the intake flow according to the engine speed, and the control plate is arranged so that the end on the intake valve side is the free end. An intake vortex control device for a direct injection diesel engine, characterized in that the control plate has a stopper provided on an inner wall of the intake port. 2. The direct injection diesel according to claim 1, wherein an elastic body for sealing is provided at the contact portion of the swirl control plate that contacts the stopper formed on the inner wall of the intake port. Engine intake vortex control device.