JPS62101824A - Intake passage for engine - Google Patents

Abstract

PURPOSE:To obtain a favorable inertial effect of intake air over wide operating areas by forming the middle part of each of independent intake passages leading from each of cylinders to a common intake passage, into a cylinder arc shaped curved part, rotatably inserting a cylindrical body through each of said curved parts which are on one axis, and making the length of a pressure wave transmitting passage variable. CONSTITUTION:An intake manifold 2 installed on the side wall 1S of the cylinder head 1 of an engine E, consists of independent intake passages 5 which are connected to the intake ports 4 of cylinders 3 and a common intake passage 6 which is connected to the upper courses of these passages 5... to distribute intake air. The upper course side of each of the independent intake passages 5... is formed into a circular arc shaped curved part 7 having a relatively large curvature radius, and a rotary body 8 having a relatively small diameter is rotatably provided in the center part of the carved part 7 of each of the passages 5..., so as to pass through the whole curved parts 7.... This rotary body 8 has openings 10 which are connected to each of the passages 5... and is rotated driven by a motor 13 controlled by a control circuit 15, according to the output of a rotation number sensor 16.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to an engine intake passageway structure, in particular an engine intake passageway that can change the pressure wave propagation length of an independent intake passageway leading to each cylinder. It's about structure.

In general, the negative pressure wave that occurs during intake is reversed into a positive pressure wave in the volume part, and this positive pressure wave is used to improve the filling efficiency. This takes advantage of the so-called intake inertia effect, which aims to improve engine output. Such an engine intake passage structure is well known.

By the way, the length of the pressure wave propagation passage necessary to obtain this type of intake inertia effect varies depending on the engine speed, so in order to obtain the intake inertia effect over a wide operating range, the length of the pressure wave propagation passage must be increased. It is necessary to change it according to the engine speed.

For this reason, for example, Japanese Patent Laid-Open No. 59-188027 proposes an engine intake passage structure including a rotating drum that changes the communication position between the surge tank and the intake passage of each cylinder.

This rotating drum needs to have the necessary volume as a surge tank, so it needs to have a large capacity.
There was also a problem in that the intake air flow was sharply bent at the communication portion, resulting in increased intake resistance.

[Object of the Invention] An object of the present invention is to provide an engine intake passage which has a structure in which the length of the pressure wave propagation passage can be made variable, is extremely compact in terms of volume, and does not cause an increase in intake resistance. The goal is to provide the following.

[Structure of the Invention] For this reason, the present invention forms an arc-shaped curved portion in the middle of an independent intake passage leading to the intake passage gathering portion of each cylinder or a group of cylinders in which the firing order is not consecutive, and each curved portion on the same axis A cylindrical body is rotatably inserted through the cylinder, and the cylinder has a
A communication opening located on a line parallel to the axis is provided for each curved portion to communicate each independent intake passage through the cylinder, and the pressure wave propagation path length of the independent intake passage can be changed by rotating the cylinder. It is characterized by being made to change.

[Effects of the Invention] According to the present invention, since the intake passage itself is formed along the curved part, the intake resistance does not increase, and since the cylindrical body communicates all the intake passages, the cylindrical body There is no need to increase the volume of the body itself, and it can be compactly incorporated into the center of the curved part so as to pass through it, making it possible to realize a compact intake passage structure with variable pressure wave propagation passage length. can.

[Embodiments] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIGS. 1 and 2, the intake manifold 2 attached to the side wall Is of the cylinder head 1 of the engine E has independent intake passages 5 communicating with the intake boats 4 of each cylinder 3, and these independent intake passages 5°. 5, . . . and a common intake passage 6 for distributing intake air.

As clearly shown in FIG. 1, the upstream side of each independent intake passage 5 has an arcuate curved portion 7 having a relatively large radius of curvature so that the intake air can flow down without encountering large intake resistance.
The upstream end of this curved portion 7 is smoothly connected to the communication port 6a provided in the common intake passage 6, and the downstream end is formed as follows.
The intake air flow is made as smooth as possible by smoothly connecting with the straight part of the independent intake passage 5 in the tangential direction.

At the center of the curved portion 7 of each independent intake passage 5, all the curved portions 7, 7. A relatively small-diameter cylindrical body 8 is rotatably supported by a bearing body 9 so as to penetrate through the cylindrical body 8. Communication openings IO are opened in the same phase at positions corresponding to each curved portion 7 of this cylindrical body 8.

Even if this cylindrical body 8 has a small volume,
All independent intake passages 5.5. . . . Each communication opening lO
Because they are in communication through the , their combined volume is sufficiently large and constitutes a volume that can invert pressure waves.

In addition, since the intake air itself flows from the common intake passage 6 to the independent intake passage 5, the communication opening 1O does not participate in the actual intake and exit of intake air, but absorbs only the pressure fluctuations and serves as a reflection point for pressure waves. .

One end of the cylindrical body 8 is formed to extend outward as a shaft, and a driven gear 12 is attached to the shaft. A driving gear 14 attached to the output shaft of a motor 13 is meshed with the driven gear 12 to rotate the cylindrical body 8 around the axis. The drive of the motor 13 is controlled by a control circuit 15, and the control circuit 15 sends a drive pulse to the motor 13 according to the engine rotation speed input from the rotation speed centimeter 16, and receives this drive pulse. The motor 13 sets the rotational phase of the cylindrical body 8, more specifically, the rotational position of the communication opening 10.

Rotating the communication opening 10 means changing the length of the pressure wave propagation path since the cylindrical body 8 has a volume that reverses pressure waves as described above.

Note that in FIG. 2, reference numeral 17 is a throttle valve provided in the common intake passage 6.

FIG. 3 shows an equivalent model of the intake passage structure shown in FIGS. 1 and 2. FIG.

As shown in this equivalent model, the communication opening 10 of the cylindrical body 8
Changing the position of indicates that the volume portion 20 corresponding to the cylindrical body 8 is moved in parallel in the longitudinal direction (passage direction) with respect to each independent intake passage 5.5°. , it is possible to change the passage length from the intake boat 4 to the volume section 20, that is, the pressure wave propagation length.

As is well known, the pressure wave propagation length required to obtain the intake inertia effect depends on the engine speed, which determines the pressure wave generation period. Qualitatively, it is longer at low speeds and longer at high speeds. Becomes shorter.

Therefore, assuming that the position of the volume portion 20 shown by the solid line (A) in FIG. 3 corresponds to the effective pressure wave propagation path length on the low speed side, when the engine speed is increased from low speed to high speed, , the volume portion 20 may be moved in the direction of the position indicated by the dotted line (B), that is, the cylindrical body 8 may be actually rotated counterclockwise as indicated by the arrow A in FIG.

Note that this rotation control does not necessarily have to be performed as a continuous function of the engine speed;
It may be divided into stages and the rotational position of the cylindrical body 8 may be changed for each stage.

FIG. 4 shows an embodiment for a six-cylinder engine.

As shown in the figure, the left and right intake manifolds ML lead to the cylinders of the left and right banks where the ignition order is not continuous.

MR has each collection part ML1. Each intake passage 21, 22 extending upstream from Mrtl and a common intake passage 23 located further upstream are connected by arc-shaped curved portions 24 and 25.

A cylindrical body 26 is rotatably inserted into the axial center of this curved portion 24.25, and by rotating this cylindrical body 26 around the axis, the position of the communication opening 27 provided in the cylindrical body 26 is changed. The length of communication between both intake passages 24 and 25 is made variable.

Therefore, in this case as well, by changing the communication length according to the engine speed, an effective intake inertia effect can be obtained over a wide operating range, and high engine output can be guaranteed.

[Brief explanation of drawings]

Fig. 1 is a vertical sectional view of an engine showing an embodiment of the present invention, Fig. 2 is a horizontal sectional view thereof, and Fig. 3 is a perspective explanatory view modeling the basic configuration of an embodiment of the present invention. , FIG. 4 is an overall schematic explanatory diagram when the present invention is applied to a six-cylinder engine. 5.5. ...Independent intake passage, 6...Common intake passage, 7...Curved portion, 8...Cylindrical body, 10
...Communication opening. Patent applicant Mazda Motor Corporation agent
Patent attorneys Aohaku Ao and 2 others Figure 1

Claims (1)

[Claims] (1) An arc-shaped curved part is formed in the middle of the independent intake passage leading to the intake passage gathering part of each cylinder or a group of cylinders in which the firing order is not consecutive, and the cylindrical body is rotated across each curved part on the same axis. The cylindrical body is provided with a communication opening located on a line parallel to the axis for each curved part so that each independent intake passage can be communicated through the cylindrical body, and can also be opened independently by rotation of the cylindrical body. An intake passage for an engine, characterized in that the length of a pressure wave propagation passage in the intake passage is varied.