JPS6124672Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an intake system for an internal combustion engine, particularly a diesel engine.

In a direct fuel injection type diesel engine, it is necessary to form a swirl of appropriate strength in order to appropriately diffuse the fuel sprayed from the injection valve within the combustion chamber and uniformly mix it with intake air. However, in engines without a swirl strength control adjustment device, the swirl strength is normally adjusted to be appropriate at medium speed rotations, so good combustion is not achieved at medium speed rotations. However, at high speeds, the swirl is too strong and the atomized fuel overlaps each other. Furthermore, at low speed rotation, the swirl is too weak and the atomized fuel is not sufficiently diffused, making it impossible to achieve optimal combustion in either case.

To this end, several means have been developed to date to control the strength of the swirl according to each speed range. Typical examples include installing a swing valve in the intake port, as disclosed in Japanese Patent Publication No. 51-7243, Japanese Patent Publication No. 51-38370, Japanese Utility Model Publication No. 51-7365, etc. It is known that the swing valve is pivoted to change the inflow cross-sectional area of the intake air, thereby changing the inflow speed of the intake air and controlling the strength of the swirl. However, these swirl control means require a swing valve element to be pivotally supported within the intake port to control the swing, and a drive mechanism must be provided in the cylinder head, which makes them mechanically complex. Furthermore, since the control movement of the swing valve element is a linear reciprocating movement within the diameter of the intake port, the control is rough and fine adjustment is difficult.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an intake system for an internal combustion engine that allows effective combustion to be obtained at all times regardless of whether the engine rotates at low or high speeds.

To this end, in the present invention, a swirl control rod is inserted into the intake port from the intake manifold, the tip of the rod is located near the throat of the intake port, and a reverse swirl control piece is formed at the tip of the rod. The overall swirl is controlled by moving the control piece in and out using a control drive means to adjust the reverse swirl.

Generally, the intake air flow of an internal combustion engine is complex, but in order to improve the efficiency of the combustion engine, a circulating flow called a swirl has been applied. In order to adjust this swirl, instead of controlling the swirl itself, if we control the reverse swirl, which is a flow that flows in the opposite direction to the swirl, the swirl can be adjusted by the flow in the opposite direction. I understand. Therefore, in the present invention, since the swirl is formed by the flow on the side of the intake port where the throat is not present, the reverse swirl can be controlled by controlling the flow flowing in from the throat side.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. Engine cylinder head 1
An intake port 2 of an appropriate shape is formed in the intake manifold 3, and the intake passage 4 of the intake manifold 3 is connected to the intake valve 10.
It communicates with At the open end of this intake port 2, there is a manifold opening 11 of the intake manifold 3.
are provided facing each other, and this multi-purpose opening 11
The swirl control means 5 is inserted into the intake port 2 by passing through the air. The swirl control means 5 includes a control rod 6, a hollow guide tube 7 for guiding the sliding movement of the control rod 6, a hydraulic cylinder 8, and a reverse swirl control piece 12 formed at the tip of the control rod 6. It consists of The hollow guide tube 7 is fitted into a through hole formed in the intake manifold 3, supports the control rod 6 inserted therein so as not to vibrate due to the intake air flow, and is connected to the outside of the intake manifold 3. leading up to. The end of the control rod 6 is fixed to a piston 9 in a hydraulic cylinder 8 as a control drive means. This piston 9 is pushed and excited to the right by a spring 14 in the hydraulic cylinder 8 in the direction shown in the figure. This hydraulic cylinder 8 is attached to the outside of the intake manifold 3, and is provided with a hydraulic pressure inlet 15 on the side opposite to the side where the spring 14 is provided, through which hydraulic pressure according to the engine speed is supplied.

The reverse swirl control piece 12 formed at the tip of the control rod 6 is located near the throat 13 of the intake port 2, but its shape can be changed in various ways. In order to control the swirl in the opposite direction that occurs near the throat 13, it is sufficient that the reverse swirl of the inhalation flow near the throat can be changed by moving the control rod 6 in and out. For example, the rod shown in FIG. 1 is a flat plate-shaped rod parallel to the longitudinal direction of the control rod 6, but as shown in FIGS. A curved plate-shaped one provided perpendicular to the direction is considered. Further, it is needless to explain that shapes other than these can be considered as examples of design changes.

Intake air flowing through the intake passage 4 of the intake manifold 3 is taken into the cylinder from the intake port 2, but at this time, it flows along the helical intake port and is taken in from the intake valve, creating a swirl as shown by the arrow. will be formed. At this time, some intake air goes around the throat of the intake port and forms a swirl in the opposite direction. The present invention attempts to control the strength of the overall swirl by controlling the reverse swirl of the throat that occurs in this way. Control of this reverse swirl is then achieved by moving the appropriate control piece in and out near the throat.

That is, when the control piece is located near the tip of the throat, the progress of the intake air flow that goes around the throat of the intake port and forms a reverse swirl is obstructed, and as a result, the swirl becomes stronger. Furthermore, when the control piece deviates from the vicinity of the tip of the throat (for example, moves to the right in the figure) and is at the position indicated by the broken line, the control piece weakens the swirl because the intake airflow that forms the reverse swirl is not obstructed by the control piece.

Therefore, by appropriately associating the position of the control part with the appropriate engine speed, it becomes possible to obtain the optimum swirl at each engine speed. Therefore, combustion is optimized, suppressing smoke emissions and insufficient output and torque that would occur due to too weak swirl, and preventing an increase in NOx that would occur due to too strong swirl. In addition, the control means does not have a conventional rocking structure, but instead controls the reverse swirl by moving the reverse swirl control piece in and out, making it possible to control the strength of the overall swirl without reducing the total flow rate of intake air. Not only is it possible, but
Fine control adjustments are possible. Furthermore, since the control device is attached to the intake manifold, the structure of the device is simple, and there is no design change to the cylinder head such as the intake port part, only the intake manifold has to be changed, so it can be installed by modifying the existing engine. It is also possible.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an engine intake system equipped with the swirl control means of the present invention, and FIGS. 2 to 4 are partial views showing a reverse swirl control section of another embodiment. 2... Intake port, 3... Intake manifold, 5... Swirl control means, 6... Swirl control rod, 12... Reverse swirl control piece, 8...
...control drive means (hydraulic cylinder).

Claims (1)

[Scope of utility model registration request] A swirl control rod is inserted into the intake port from the intake manifold, the tip of the rod is located near the throat of the intake port, a reverse swirl control piece is formed at the tip of the rod, and the control drive means controls the swirl control rod. An intake system for an internal combustion engine, characterized in that the overall swirl is controlled by adjusting the reverse swirl by moving the control piece in and out.