JPH0444818Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] This invention provides an intake port in the cylinder head of an engine and also provides a bypass passage, which can be opened and closed via an actuator such as an air cylinder. This invention relates to an improvement of a piston-type variable swirl mechanism.

[Conventional technology]

Swirl is a swirling motion of the air-fuel mixture generated around the cylinder axis of the engine, and by changing the swirl ratio, it is possible to improve fuel efficiency, low-temperature startability, etc.

For this purpose, as shown in FIG. 1, an intake port P communicating with an intake manifold M is provided in the cylinder head H of the engine, and a spiral portion S is formed in the intake port P at the upper part of the intake valve. In swirl generation using a so-called helical port, in which the intake air-fuel mixture is swirled in advance and then sucked into the cylinder, a bypass passage B is provided that communicates with the intake manifold M and opens at the terminal end of the intake port P. The inlet can be opened and closed by an actuator 1 such as an air cylinder, and the actuator 1 is configured to blow air from the bypass passage B to the terminal end of the intake port P to reduce swirl when the engine is running at high speed. A system has been developed in which the bypass passage B is opened and closed by turning on and off an electromagnetic valve V interposed between the engine and the tank T using a rotation sensor that detects the rotational speed of the engine. That is, low swirl is generated at startup and in the high speed rotation range, and high swirl is generated in the medium and low speed rotation range.

[Problem that the invention attempts to solve]

However, as shown in FIG. 2, the conventional actuator 1 used at this time has a configuration in which an abutment plate 3 with a flat front surface is connected to the tip of the piston rod 2, so that the cylinder head H is bypassed. The contact with the entrance of the passage B is a plane-to-plane rigid contact, which not only causes problems in sealing performance, but also has drawbacks such as uneven contact and stepped wear.

Further, there is a problem in that it is difficult to improve accuracy in order to eliminate such drawbacks due to cost and manufacturing limitations.

[Means for solving problems]

In view of the above, the present invention does not require that much precision, can therefore be manufactured at low cost, and not only does the sealing function not be impaired by vibrations or vibrations, etc. It was devised to provide a device that does not cause uneven contact, uneven wear, etc., and its gist is that a bypass passage that communicates with the intake manifold and opens at the terminal end of the intake port is provided with a through hole around it. The piston-type variable swirl mechanism is configured to open and close by sliding a cylindrical tube into the bypass passage, and the cylindrical tube is connected to a piston rod of an actuator that operates the cylindrical tube.

〔Example〕

Hereinafter, the present invention will be explained in detail based on the embodiment shown in FIG. 3. Reference numeral 1 denotes an actuator such as an air cylinder, and a cylindrical tube 4 having a plurality of through holes 4a is connected to the tip of the piston rod 2. has been done.

The tip of this cylindrical tube 4 is slidably inserted into a guide tube 5 inserted into a bypass passage B provided in the cylinder head H, and the actuator 1 is actuated to move the cylindrical tube 4 forward. When this occurs, the through hole 4a is located within the guide tube 5 and is closed. That is, when the actuator 1 is not operating, the air-fuel mixture passes through the vent 4a and flows into the cylindrical pipe 4.
When the actuator 1 is activated, the air-fuel mixture flows through the bypass passage B by closing the through hole 4a, thereby blocking the flow of the air-fuel mixture within the bypass passage B.

The guide tube 5 is provided to prevent the cylinder head H from being worn out and to allow the cylindrical tube 4 to slide more easily and reliably.

Since the cylindrical tube 4 slides within the guide tube 5 to open and close the bypass passage B, it is not necessary to increase the accuracy so much, and furthermore, the sealing function is prevented from being impaired.

[Effect of idea]

The piston-type variable swirl mechanism according to the present invention is
As described above, the bypass passage communicating with the intake manifold and opening at the terminal end of the intake port is configured to be opened and closed by sliding a cylindrical pipe with a through hole around the circumference into the bypass passage, and the cylindrical pipe Because it is connected to the piston rod of the actuator that operates it, there is no uneven contact or stepped wear unlike in conventional mechanisms, and the sealing function is not impaired by vibration or vibration. Therefore, the swirl ratio of the intake port can be stably supplied from the beginning without any change over time, and there is no need for the accuracy to be that high. There are various effects.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an outline of a piston type variable swirl mechanism, FIG. 2 is a longitudinal sectional view showing a conventional example, and FIG. 3 is a longitudinal sectional view showing an embodiment of the present invention. 1...actuator (air cylinder), 2
... Piston rod, 4 ... Cylindrical tube, 4a ... Through hole, 5 ... Guide tube, H ... Cylinder head, B
...Bypass passage, P...Intake port, M...Intake manifold.

Claims (1)

[Scope of utility model registration request] A bypass passage communicating with the intake manifold and opening at the terminal end of the intake port is configured to be opened and closed by sliding a cylindrical pipe provided with a through hole around the bypass passage into the bypass passage, and the cylindrical pipe is operated. A piston-type variable swirl mechanism characterized by being connected to a piston rod of an actuator.