JPH0392534A - Intake device for multi-cylinder engine - Google Patents

Abstract

PURPOSE:To improve intake filling efficiency together with resonance effect and inertia effect by dividing a collecting chamber collecting branch passages for cylinders and an upstream passage connected at its upstream end with a bulkhead along their axes, and providing a communicating hole opened or closed by a switching valve on the bulkhead. CONSTITUTION:The first through fourth passages 121-124 connected to combustion chambers of individual cylinders are collected into a collecting chamber 13 at the upstream end section, and the upstream end of the collecting chamber 13 is connected to an air cleaner 16 via an upstream passage 14. A bulkhead 17 extended along their axes is provided in the portion at the middle section between the collecting chamber 13 and the upstream passage 14, and four cylinders are divided into two groups each consisting of two cylinders having a uniform interval between intake strokes. A communicating hole 17a communicating the first and second collecting chambers 131 and 132 is formed near the downstream side end face 13a of the collecting chamber 13 on the bulkhead 17, and a switching valve 18 is provided here. This switching valve 18 is closed in a low-rotation area and opened in a high-rotation area.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to an intake system for a high-pressure engine, a plurality of branch passages connected to each cylinder, a gathering chamber where these branch passages gather, and This article relates to an intake system for a multi-cylinder engine that is composed of an upstream passage connected to the upstream side. In recent years, in order to improve the output performance of automobile engines, efforts have been made to utilize dynamic effects of intake air within the intake system, such as inertia effects and resonance effects, to increase intake air filling efficiency. There are cases where In this case, the intake system is provided with a collection part such as a surge tank to which the upstream passage led from the air cleaner is connected, and the same number of branch passages as the number of cylinders branched from the collection part are connected to each air intake system. It is configured to connect.

According to such an ellipse, by making the gathering part act as an atmosphere release part that reverses the negative pressure wave generated in the downstream part of the branch passage when the intake valve opens into a positive pressure wave, the intake air filling amount due to the inertial effect can be reduced. Furthermore, by making the space formed by the gathering portion and the upstream passageway act as a resonance space for pressure vibrations within the intake system, an effect of increasing the intake air filling amount due to the resonance effect can be obtained.

By the way, conventionally, as the above-mentioned gathering part, a long and narrow surge tank-like structure is often used, in which an upstream passage is connected to the wall surface of one end or the center of the peripheral wall surface, and each branch passage is arranged in parallel on the peripheral wall surface. However, in the case of such a gathering part, the distance from the connection part of the upstream passage to the connection part of each branch passage and the length of each branch passage are different, so the distribution of intake air to each cylinder may be affected. Alternatively, the effect of inertia on each cylinder becomes uneven, and the flow path of intake air from the opening of the upstream passage to the opening of each branch passage becomes sharply curved, which increases the intake resistance of intake air. will increase.

In response to this, for example, Japanese Utility Model Application Publication No. 60-88062 discloses a gathering part having a shape as shown in FIG. 7.
In other words, this collecting part A has a substantially truncated conical shape, and the shape of the collecting part itself and the large diameter The openings of each of the branch passages C...C opening at the side end faces are arranged approximately line symmetrically.

According to this, the opening B of the upstream passage in the gathering part A
The distance from the opening of each branch passage C...C and the length of each branch passage C...C are approximately equal, which improves the distribution of intake air to each cylinder and the effect of inertia on each cylinder. In addition, the intake air flow path is no longer sharply curved, reducing intake resistance, and as a result, intake air filling efficiency and engine output performance are improved. In addition, since the upstream ends of the branch passages C...C open close to the downstream end face of the collecting portion A, each branch passage C...
・C acts as an air release space for other branch passages C, and therefore the volume of the gathering part A can be reduced. (Problem to be Solved by the Invention) By the way, the above-mentioned inertial effect is caused by the negative pressure wave generated in the downstream part of the branch passage when the intake valve is opened propagating upstream in the passage, and the air release part (collecting part) The greatest supercharging effect is obtained when this positive pressure wave is reversed into a positive pressure wave and changed direction downstream, and then reaches the downstream end of the branch passage just before the intake valve closes. The effect is greatest at a specific engine speed where the time for the pressure wave to travel back and forth through the branch passage twice is approximately equal to the time from opening to closing of the intake valve. In addition, the resonance effect occurs when the negative pressure waves that occur sequentially when the intake valves in each cylinder open act as an excitation force for intake vibration, and the vibration frequency changes to the natural frequency of the resonant space consisting of the collecting section and its upstream passage. When they match, a large supercharging effect can be obtained, so the effect is maximized at a specific engine speed. In other words, dynamic effects such as the inertial effect and resonance effect of the intake air can only be obtained at a specific tuned rotational speed and a rotational speed in its vicinity for a given shape of the intake system, and are limited to a wide range of engine rotational speeds. Generally, when using inertia effect, the tuning speed is set to a relatively high speed, and when using resonance effect, the tuning speed is set to a relatively low speed. It is customary to set the rotation speed.

SUMMARY OF THE INVENTION Therefore, the present invention aims to provide an intake system that achieves uniform distribution of intake air, reduces intake resistance, etc., so that the supercharging effect due to the dynamic effect of intake air can be obtained over a wide range of engine rotations. The task is to (Means for Solving the Problems) In order to solve the above problems, the present invention is characterized by being configured as follows.

That is, the intake system for a multi-cylinder engine according to the present invention has the following features:
A cylinder that has four or more cylinders that can be grouped into multiple cylinders whose intake strokes are equally spaced, and that has the same number of branch passages as the number of cylinders connected to each cylinder, and a collection of these branch passages. a chamber, and an upstream passage connected to the upstream side of the gathering chamber, and the gathering chamber has an axis in substantially the same direction as the axis at the opening at the upstream end of each of the branch passages, and has an upstream passageway connected to the upstream side of the gathering chamber. In a configuration in which the cross-sectional area smoothly changes from the upstream end face to which the passages are connected to the downstream end face having a larger cross-sectional area than the upstream end face to which each branch passage is connected, the gathering chamber and the upstream passage is divided into a plurality of gathering chambers and upstream passages for each cylinder group by partition walls extending along these axes. A communication hole is provided in the vicinity of the downstream end face of the collecting chamber in the partition wall for communicating the divided collecting chambers with each other, and an on-off valve is provided in the communicating hole, which closes in a low engine speed range and opens in a high engine speed range. It is characterized by having the following.

(Function) According to the above configuration, in the low rotation range of the engine, rM
Since the closing of the valve closes the communication hole provided in the partition wall that divides the gathering chamber and the upstream passage, the gathering chamber and the upstream passage are completely divided into a plurality of cylinder groups. In that case, the gathering chamber and upstream passage are divided into groups of cylinders whose intake strokes are equally spaced, so in each group, the intake air of each cylinder is divided into the divided gathering chamber and upstream passage. Pressure vibrations with a frequency proportional to the engine speed are generated using the negative pressure waves generated during stroke as an excitation force. Then, the natural frequency of the space is set so that this pressure vibration resonates within the resonance space formed by the divided gathering chamber and the upstream passage at a predetermined rotation speed in a low engine rotation region. As a result, large pressure oscillations occur due to the resonance phenomenon, which causes a supercharging effect of intake air to the combustion chamber.

Furthermore, in the high rotational range of the engine, the on-off valve opens the communication hole provided in the partition wall, so that the entire inside of the collective chamber becomes a relatively large space with a required volume. Therefore, when the negative pressure wave generated in the downstream part of the branch passage when the intake valve of each cylinder is opened propagates upstream through the branch passage and reaches the collecting chamber, the collecting chamber acts as an atmosphere release part. Negative pressure waves will definitely be reversed into positive pressure waves. Therefore, by appropriately setting the length of each branch passage, etc., the above positive pressure wave can reach the downstream end of the branch passage just before the intake valve closes at a predetermined rotation speed in the high engine rotation range. As a result, a supercharging effect of intake air into the combustion chamber can be obtained due to the inertial effect.

In particular, the gathering chamber has an axis in substantially the same direction as the axis at the opening at the upstream end of each of the branch passages, and from the upstream end face where the upstream passage opens to the upstream end face where each branch passage opens. The cross-sectional area changes smoothly toward the downstream end face, which has a large cross-sectional area, so it is compact, reduces intake resistance, and evens out the distribution of intake air to each cylinder. In combination with the resonance effect and inertia effect described above, the intake air filling efficiency or engine output is effectively improved.

(Example) Examples of the present invention will be described below.

FIG. 1 shows an embodiment in which the present invention is applied to an in-line four-cylinder engine, and an intake manifold 10 according to this embodiment includes a flange portion 11 attached to the cylinder head (not shown) of the engine, and a flange portion 11 attached to the cylinder head (not shown) of the engine. first to fourth branch passages 12+ to 124 having one end connected to the section 11 and communicating with the combustion chambers of the first to fourth cylinders via the intake boat in the cylinder head, and these branch passages 121;
A gathering chamber 13 where the upstream ends of the upstream sections 1 to 124 gather, and an upper flow 1 extending from the gathering chamber 13 to the upstream side. il4, and an air cleaner 16 is attached to the upstream end of the upstream passage 14 via an air flow meter 15.

The above-mentioned branch passages 121 to 124 are bent so that the lengths are approximately equal, and the upstream parts are integrally bundled, and the upstream opening ends 12a...12a are close to each other and the above-mentioned collective chamber 1 It is opened at the end face 13a on the downstream side. In addition, this gathering room 13 includes each of the branch passages 121 to
124, and has an axis in substantially the same direction as the axial direction of the opening ends 12a...12a of the upstream passage 14, and has a cross-sectional ram that is smooth from the upstream end surface 13b to which the downstream end of the upstream passage 14 is connected to the downstream end surface 13a. It is said that the shape changes.

Furthermore, inside the collection chamber 13 and the upstream passage 14, there is a partition wall 1 extending along the axis thereof.
7 is provided, and the partition wall 17 separates the gathering room 13 from the first,
The downstream portion of the upstream passage 17 is divided into second gathering chambers 13+, 132, and into first and second upstream passages 14+, 142. In that case, the partition wall 17 separates the branch passages 122, 123 of the second and third cylinders from the first gathering chamber 13+ to the first
The branch passages 12+ and 124 of the first and fourth cylinders are communicated with the second collecting chamber 132 and the second upstream passage 142, that is, the intake order of each cylinder is #1. -#3→#4-#2, the cylinders are grouped into two cylinders whose intake strokes are equally spaced,
They are provided so as to communicate with the first and second gathering chambers 1.31 and 132 and the first and second upstream passages 141 and 142, respectively. As shown in an enlarged view in FIG.
Communication hole 1 that communicates the first and second gathering chambers 131 and 132
7a, and an on-off valve 18 for opening and closing the communication hole 17a.

This opening/closing valve 18 is provided with a rotating shaft 18a that penetrates inside the partition wall 17 and projects to the outside, and by rotating the shaft 18a, the communicating hole 17a is opened and closed. A negative pressure diaphragm type actuator 21 is provided which rotates this rotation shaft 18a via a rod 20 and a negative pressure diaphragm actuator 21. Further, the actuator 21 is provided with a vacuum tank 23 that supplies operating negative pressure via a three-way solenoid valve 22, and a controller 24 that controls opening and closing of the three-way solenoid valve 22. The controller 24 detects the engine rotation speed. A signal S1 from an engine rotation sensor 25 is input. Then, the controller 24 controls the actuator 21 in a low rotation range where the engine rotation speed indicated by the signal S1 is below a predetermined value.
so that the on-off valve 18 closes the communication hole 17a through the on-off valve 1? A control signal S2 is output to the three-way solenoid valve 22 so as to open the communication hole 17a.

Next, the operation of this embodiment will be explained.

First, in the low engine speed range where the engine speed is below a predetermined value,
Due to the operation of the controller 24 and the actuator 21, the on-off valve 18 closes the communication hole 17a provided in the partition wall 17 that divides the downstream part of the gathering chamber 13 and the upstream passage 14, so that the gathering chamber 13 and the upstream passage 14 are closed. The first and second gathering chambers 131, 132 and the second upstream passages 14+ and 14
It will be completely divided into two. In that case, the first gathering chamber 13+ or the first upstream passage 141 communicates with the branch passage 122123 of the second and third cylinders whose intake strokes are equally spaced, and the second gathering chamber 132 or the second upstream passage Road 142
By communicating with the branch passages 1i'812+, 124 of the first and fourth cylinders whose intake strokes are equally spaced, the divided collecting chambers 131, 132 and the upper passages are connected in each of these two groups. Road 141. In each of the resonance spaces 1 and 14, pressure oscillations occur at a frequency proportional to the engine rotational speed using the negative pressure waves generated during the intake stroke of each cylinder as an excitation force. Then, at a predetermined speed in the low engine speed range, this pressure oscillation causes the above-mentioned resonance space ■
By matching the natural frequencies of , ■, large pressure vibrations occur in the above spaces ■ and ■ around the engine rotational speed due to a resonance phenomenon, and this pressure vibration has the effect of supercharging the intake air into the combustion chamber. By doing so, the intake air filling amount increases. As a result, as shown by the broken line in FIG. 3, an engine output characteristic having a high peak at a predetermined low engine speed N1 is obtained.

On the other hand, in the high rotation range of the engine, the on-off valve 18 opens the communication hole 17a provided in the partition wall 17, so that the gathering chamber 1
3 is a relatively large space having a required volume, and acts as an atmosphere release section for each of the branch passages 12+ to 124. Therefore, when the negative pressure waves generated at the downstream ends of the branch passages 121 to 124 when the intake valves of each cylinder are opened propagate upstream through the branch passages 12, to 12, and reach the gathering chamber l3, Downstream end surface 13 of gathering room 13
It will definitely be reversed into a positive pressure wave at point a. Therefore, each branch passage 12. By appropriately setting the length of 124 to 124, the positive pressure wave described above is caused to flow into the branch passage 12. ~12
, and a supercharging effect of the intake air into the combustion chamber is obtained, and due to this inertial effect, the engine has a high peak at a predetermined high engine speed N2, as shown by the chain line in FIG. Therefore, the above predetermined engine speed N I + N 2
By opening or closing the on-off valve 18 at an intermediate rotational speed N3, as shown by the solid line in Fig. 3, both the resonance effect and the inertia effect are utilized, and the output is improved over a wide engine rotation range. This means that the characteristics can be obtained. In particular, the gathering room 13 is connected to each of the branch passages 121
An upstream end surface 1 having an axis in substantially the same direction as the axis at the opening at the upstream end of ~124, and in which the upstream passage 14 opens.
The cross-sectional area changes smoothly from 3b to the downstream end face 13a, which has a larger cross-sectional area than the upstream end face 13b, where each of the branch passages 121 to 124 opens.
The curvature of the intake air flow path is reduced, reducing intake resistance, and the distribution of intake air to each cylinder is made more uniform, which, together with the resonance effect and inertia effect mentioned above, effectively improves engine output. I will do it. In addition, each branch passage 121~
Since the upstream ends 12a...12a of 124 are close to each other and open to the downstream end surface 13a of the gathering chamber 13, each branch passage 121 to 124 is an atmosphere open space with respect to the other branch passages due to the inertial effect. Therefore, the volume of the collection chamber 13 itself can be relatively small.

Next, a second embodiment of the present invention shown in FIG. 4 will be described.

In this embodiment, the present invention is applied to an in-line six-cylinder engine, and similarly to the first embodiment, the intake manifold 30 has one end connected to the flange portion 31 and has approximately equal lengths. So that it becomes? Six curved branch passages 3
2. ~ 326, a collection chamber 33 where the upstream parts of these branch passages 321 to 326 gather in an integrally bundled state, and an upstream passage 34 extending upstream from the collection chamber 33. ．． In addition, the gathering room 33 includes each branch passage 3.
The upstream passage 34 has an axis in substantially the same direction as the axis at the upstream opening ends 32a...32a of 21 to 326.
From the upstream end surface 33b connected to each branch passage 321~
326 is connected to the downstream end surface 33a, which has a larger cross-sectional area than the upstream end surface 33b.

The gathering chamber 33 and the upstream passage 34 are connected to the branch passages 321 to 323 of the first to third cylinders whose intake strokes are equally spaced through a partition wall 37 extending along these axes. 331 and the first upstream passage 34s, and the branch passage 3 of the fourth to sixth cylinders whose intake strokes are equally spaced.
The partition wall 37 is divided into a second collecting chamber 33 and a second upstream passage 342 communicating with the collecting chambers 24 to 326, and a first
, a communication hole 37 that communicates the second gathering chambers 33+ and 33x.
an opening/closing valve 3 that is provided with a opening and closing valve 3 that opens and closes the communication hole 37a;
8 is provided.

Similar to the first embodiment, this opening/closing valve 38 closes the communication hole 37a in a low engine rotation range below a predetermined rotation speed and closes the communication hole 37a in a high engine rotation range above a predetermined rotation speed by the operation of a controller and an actuator (not shown). The communication hole 37
It is designed to open a.

Therefore, in this embodiment as well, similar to the first embodiment, a resonance effect is obtained in the low engine speed region and an inertial effect is obtained in the high engine speed region, the intake resistance is reduced, and the air flow to each cylinder is reduced. The distribution of intake air and the effects of the resonance effect and inertia effect on each cylinder are made uniform, increasing the amount of intake air filling and, in turn, improving the engine output over a wide rotational range. In addition, each branch passage 32. ~326
The upstream end portions 32a...32a of the upstream end portions 32a are close to each other and open to the downstream end surface 33a of the gathering chamber 33? Therefore, each of the branch passages 321 to 326 acts as an air release space for the other branch passages, and the gathering room 33 is formed into a compact ellipse. Furthermore, the third embodiment shown in FIGS. 5 and 6 is an example in which the present invention is applied to a V-type engine in which two banks each having three cylinders arranged in series are arranged in a V-shape. The intake manifold 40 according to this embodiment has first and second
2 connected to the cylinder heads of banks A and B, respectively.
Two flange portions 411. 41■, three branch passages each having one end connected to these flange parts 41+412, a total of six branch passages 421-426, and these branch passages 421-426.
The upstream portions of the tubes 426 are horizontally constituted by a gathering chamber 43 where they gather in an integrally bundled state, and an upstream passage 44 extending upstream from the gathering chamber 43.

Further, the gathering chamber 43 has an axis in substantially the same direction as the axis at the upstream opening end of each of the branch passages 42r to 426, and the branch passages 421 to 426 are connected to each other from the upstream end surface 43b to which the upstream passage 44 is connected. ? The upstream end surface 4
The cross-sectional area smoothly changes toward the downstream end face 43a, which has a larger cross-sectional area than that of the downstream end face 3b.

Also in this embodiment, the gathering chamber 43 and the upstream passage 44 are separated into branch passages 421 to 423 of the first to third cylinders whose intake strokes are equally spaced by a partition wall 47 extending along these axes. The first gathering room 43+ and the first
The upstream passage 44■ and the fourth passage whose intake strokes are equally spaced
~ It is divided into a second gathering chamber 432 and a second upstream passage 44 which communicate with the branch passages 424 to 426 of the sixth cylinder, and the downstream end surface 4 of the gathering chamber 43 at the partition wall 47.
A communication hole 47a that communicates the first and second gathering chambers 4343 is provided in the vicinity of 3a, and an on-off valve 48 that opens and closes the communication hole 47a is provided. Similarly to the first and second embodiments, this on-off valve 48 also closes the communication hole 47a in a low engine rotation range below a predetermined rotation speed, and closes the communication hole 47a in a high engine rotation range above a predetermined rotation speed. It is designed to open.

Therefore, in this embodiment as well, a resonance effect can be obtained in the low rotation range of the engine, and an inertia effect can be obtained in the high rotation range of the engine, the intake resistance is reduced, and the distribution of intake air to each cylinder is improved. -Il: The effects of the noise effect and the inertial effect are made uniform, and the intake air filling efficiency or engine output performance is improved, and the gathering chamber 43 is arranged in a compact manner.

In addition, in this embodiment, each branch passage 421 to 42
6 are bent so that their lengths are approximately equal and guided toward the second bank B, and are gathered above the second bank B. As shown in Fig. 6, when the engine is mounted in the engine room X of a vehicle with the axis of the crankshaft oriented laterally, the second bank B located at the rear and the upper part of the engine room This is to store the engine by effectively utilizing the space created between the bonnet Y and the covering bonnet Y.

(Effects of the Invention) As described above, according to the present invention, there are branch passages of the same number as the number of cylinders connected to each cylinder, a gathering chamber where the upstream ends of these branch passages gather, and a passageway upstream from the gathering chamber. In an intake system for a multi-cylinder engine having an upstream passage extending to the side, intake resistance is reduced and the distribution of intake air to each cylinder is improved. In each region, the inertial effect of intake air is obtained. As a result, the intake air filling amount is increased over a wide rotational range of the engine, and the engine output performance is effectively improved. Further, the gathering room and, by extension, the intake device can be configured compactly.

[Brief explanation of drawings]

1 to 6 show embodiments of the present invention, in which FIG. 1 is a perspective view of an intake manifold according to the first embodiment, FIG. 2 is an enlarged sectional view of the main part thereof, and FIG. 3 is the embodiment. FIG. 4 is a perspective view of the intake manifold according to the second embodiment, FIG. 5 is a plan view of the intake manifold and its surroundings according to the third embodiment, and FIG. 6 is a diagram of FIG. It is a sectional view taken along the Vl line. Furthermore, FIG. 7 is a plan view of an intake manifold showing the prior art of the present invention. 10,30.40...Intake manifold, 121-12
4.321~32a, 42+~426...branch passage,
13, 33.43... Meeting room, 14, 34.44...
・Upstream passage, 17, 37.47... Bulkhead, 17a, 3
7a, 47a...Communication hole, 18,38.48...Opening/closing valve. Jirei 31 7 Zubue 5 Zubue 6

Claims (1)

[Claims] (1) It has four or more cylinders that can be grouped into multiple cylinders whose intake strokes are equally spaced, and the same number of branch passages as the number of cylinders connected to each cylinder, and the number of branch passages connected to these branch passages. It has a gathering chamber in which the upstream ends gather together, and an upstream passage connected to the upstream side of the gathering chamber, and the gathering chamber is arranged in substantially the same direction as the axis of the opening at the upstream end of each of the branch passages. A multi-cylinder engine having an axis and having a shape in which the cross-sectional area smoothly changes from an upstream end face where an upstream passage opens to a downstream end face having a larger cross-sectional area than the upstream end face where each branch passage opens. An intake device,
The gathering chamber and upstream passage are divided into a plurality of gathering chambers and upstream passages for each cylinder group by a partition wall extending along the axis thereof, and divided into positions near the downstream end face of the gathering chamber on the partition wall. An intake system for a multi-cylinder engine, characterized in that a communication hole is provided for communicating the collecting chambers with each other, and the communication hole is provided with an on-off valve that closes in a low rotation range of the engine and opens in a high rotation range of the engine.