JPH0429068Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention is provided in an engine having a plurality of cylinder sections each including at least one cylinder, and two cylinder sections each communicating with a separate cylinder section. The present invention relates to an intake system for a multi-cylinder engine that guides intake air to each cylinder section through two divided intake passage sections.

(Prior Art) In order to improve the efficiency of intake air supply to the cylinders of an engine, it is known to utilize the dynamic effect of intake air that flows through the intake passage and is guided to the cylinders.
The present applicant previously disclosed in Japanese Patent Application No. 59-40682,
As an engine intake system that aims to improve the intake air supply efficiency to each cylinder of a multi-cylinder engine by utilizing the dynamic effect of intake air, we have developed an engine intake system that uses a plurality of cylinders that are not in consecutive order for a multi-cylinder engine. An intake passage is provided in which two separate intake passage sections are formed to individually guide intake air into each of two cylinder sections including a cylinder section, and a surge tank is interposed in each of the two section intake passage sections of the intake passage. We are proposing a configuration that looks like this.

In this way, in an intake system for a multi-cylinder engine that has an intake passage configuration in which intake air is guided to each of two cylinder sections via two independent divided intake passage sections, the amount of intake air introduced into the two cylinder sections is In order to equalize the intake air flow, a throttle valve is provided in each of the two divided intake passage sections, and these throttle valves are opened and closed at the same time.

(Problem to be solved by the invention) As mentioned above, the two cylinders each communicate with a separate cylinder section.
In an intake system for a multi-cylinder engine in which a throttle valve is arranged in each of the two divided intake passages to open and close them simultaneously, the passage cross-sectional area of each divided intake passage is compared in order to obtain a predetermined intake flow rate. Under the condition that the throttle valve is widened, efficient intake air is supplied to each cylinder according to the opening degree of each throttle valve. However, in such a case, since efficient intake air is supplied to each cylinder,
When the accelerator pedal is slightly depressed and the throttle valve is slightly rotated from the fully closed state in response, the amount of intake air guided from each section passage section to the cylinder section with which it communicates rapidly increases. As a result, there is a possibility that a sudden change in engine torque may occur.

In view of this, the present invention provides at least one
For a multi-cylinder engine having a plurality of cylinder sections each having two cylinders, the engine has two sectioned intake passage sections each communicating with a separate cylinder section and guiding intake air to each cylinder section; A throttle valve is arranged for each of the intake passage sections, and these valves are opened and closed simultaneously to adjust the amount of intake air flowing through each section of the intake passage section, depending on the opening degree of each throttle valve for each cylinder section. In addition, when the accelerator pedal is slightly depressed, engine torque due to a sudden increase in the amount of intake air guided to each cylinder can be achieved. An object of the present invention is to provide an intake system for a multi-cylinder engine that is capable of suppressing the occurrence of sudden fluctuations in air pressure.

(Means for Solving the Problems) In order to achieve the above-mentioned object, an intake system for a multi-cylinder engine according to the present invention includes first and second cylinder sections each communicating with separate cylinder sections each including at least one cylinder. a first throttle valve passage for guiding intake air into the first intake passage section through a first throttle valve; and a first throttle valve passage section for guiding intake air into the first intake passage section through a second throttle valve; A second throttle passage leading to the intake passage is arranged in parallel with the first and second throttle passages, and the intake air is distributed to the first and second divided intake passages via a third throttle valve. A third throttle passage section is provided, and a first and second throttle passage section in the first and second throttle passage sections is provided.
The three throttle valves are opened and closed at the same time, and the third throttle valve in the third throttle passage is opened earlier than the opening timing of the first and second throttle valves. and configured.

(Function) In the multi-cylinder engine intake system according to the present invention as described above, when the accelerator pedal is depressed by a predetermined amount, in addition to the third throttle valve, the first and second throttle valves are The throttle valve is opened with an opening degree corresponding to the amount of depression of the accelerator pedal, and intake air is
and a second throttle passage section, the first
and the second divided intake passage, and are supplied individually and equally to each of the cylinder parts with which the first and second divided intake passages communicate.

Further, when the accelerator pedal is slightly depressed, only the third throttle valve is opened while the first and second throttle valves are fully closed, and the intake air is transferred to the third throttle valve. A relatively small amount of intake air is evenly distributed to the first and second segmented intake passages via the passage, and this distributed intake air is distributed to the cylinder section with which the first and second segmented intake passages communicate. be guided individually by each of them. Therefore, even if the accelerator pedal is only slightly depressed, the amount of intake air guided to each cylinder section will not be rapidly increased, and therefore, no sudden fluctuations in engine torque will occur. Thereafter, when the accelerator pedal is further depressed, the first and second throttle valves are opened in addition to the third throttle valve. That is,
The first and second throttle valves are opened at a timing later than that of the third throttle valve.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view showing a schematic configuration of a main part of an example of an intake system for a multi-cylinder engine according to the present invention, and FIG. 2 is a cross-sectional view taken along the line - in FIG. 1.

The engine to which the example shown in FIGS. 1 and 2 is applied has six cylinders: first, second, third, fourth, fifth, and sixth cylinders. Third
It is provided with two cylinder parts: a first cylinder part including cylinders and a second cylinder part including fourth, fifth, and sixth cylinders. The ignition order of these first to sixth cylinders is set, for example, as follows: first cylinder→fifth cylinder→third cylinder→sixth cylinder→second cylinder→fourth cylinder.

An example of an intake system for a multi-cylinder engine according to the present invention that guides intake air to each of the first to sixth cylinders described above includes a branch passage section 11, a branch passage section 11, as the most downstream section of the intake passage.
12, 13, 14, 15 and 16,
The branch passage sections 11, 12, and 13 communicate the first, second, and third cylinders included in the first cylinder section with the first surge tank 18, and also connect the first surge tank 18 with the first surge tank 18.
4, 15 and 16 are the fourth, fifth and sixth cylinders included in the second cylinder section and the second surge tank 19
It is designed to communicate with 1st and 2nd
On the upstream side of the surge tanks 18 and 19,
The first and second surge tanks 18 and 19 and the divided intake passages 20 and 21 have a partition plate 22 as a common side wall, and are connected to each other at a predetermined level. It forms a divided space with capacity.

A throttle body 24 having a concrete configuration as shown in FIG. 3, for example, is connected to the upstream side of each of the divided intake passages 20 and 21. This throttle body 24 has a first throttle passage part 26 and a second throttle passage part 26 having the same passage cross-sectional area.
A throttle passage section 27 is provided between the first throttle passage section 26 and the second throttle passage section 27, and the passage cross-sectional area is a first throttle passage section 27.
a third throttle passage section 28 smaller than the throttle passage section 26 and the second throttle passage section 27;
are arranged side by side. These first, second and third throttle passages 26, 27 and 28 have first, second and third throttle passages as shown in detail in FIGS. 3 and 4, A and B. Throttle valve 3
1, 32 and 33 are arranged, respectively.

The first and second throttle valves 31 and 32 are
The tubular rotating shafts 36 and 37 are respectively composed of valve body portions 31a and 32a supported by these, and the tubular rotating shafts 36 are connected to the throttle body 24.
A semi-cylindrical fixing part 3 to which the cylindrical shaft part 36a rotatably supported and the valve body part 31a are fixed.
6b, and the tubular rotating shaft 37 is formed of a cylindrical shaft portion 37a rotatably supported by the throttle body 24 and a semicylindrical fixing portion 37b to which the valve body portion 32a is fixed. has been done. On the other hand, the third throttle valve 33 is composed of a rotating shaft 38 and a valve body portion 33a supported by the rotating shaft 38, and the rotating shaft 38 is a cylindrical shaft portion of the first and second throttle valves 31 and 32. A cylindrical shaft portion 38a that penetrates through 36a and 37a and slides on the inner surface thereof, and a semi-cylindrical fixing portion 36 of the first and second throttle valves 31 and 32, to which the valve body portion 33a is fixed.
b and 37b and slidably contact the inner surfaces thereof, and is formed at a predetermined angle θ ₁ with respect to the semi-cylindrical fixing parts 36b and 37b.
It is formed by a fan-shaped fixing part 38b whose axial cross section is rotatable by a sector. And the third
One end of the rotating shaft 38 of the throttle valve 33 is extended outside the throttle body 24 and connected to an accelerator pedal (not shown) by a throttle wire 41, and the rotating shaft 38 rotates in response to depression of the accelerator pedal. I am forced to do it.

Further, on the upstream side of the throttle body 24, the first section of the throttle body 24,
A common intake passage section 30 leading to the second and third throttle passage sections 26, 27 and 28 is connected. Intake from this common intake passage section 30 passes through the third throttle passage section 28 to the divided intake passage section 2.
When guided to the 0 and 21 sides, the partition plate 22 separates the intake air that has passed through the third throttle passage section 28 into the divided intake passage sections 20 and 2.
1 will be equally distributed to both.

In this example configured as described above, when the accelerator pedal is depressed, first, the rotation shaft 38 of the third throttle valve 33 is moved so that the throttle wire 41 is in the direction indicated by the white arrow T in FIG. The third
The throttle valve 33 is changed from a fully closed state as shown in FIG. 4A to an open state as shown in FIG. 4B.
8b rotates inside the semi-cylindrical fixing part 37b while sliding on its inner surface, the first and second throttle valves 31 and 32 are fully rotated until the rotation angle of the rotating shaft 38 reaches the angle θ ₁ . kept closed.

Therefore, when the accelerator pedal is slightly depressed, the rotation angle of the rotation shaft 38 of the third throttle valve 33 does not reach the angle θ ₁ , and the rotation angle of the rotation shaft 38 of the third throttle valve 33 does not reach the angle θ 1
The throttle valves 31 and 32 are fully closed,
Only the third throttle valve 33 is left slightly open. Therefore, the intake air from the common intake passage section 30 is transferred to the third throttle passage section 2, which has a small diameter.
8, the third throttle valve 33 is slightly opened to open the divided intake passage sections 20 and 2 by a small amount through the effective intake passage with a small cross section.
1 side, and is evenly distributed to each of the segmented intake passages 20 and 21 without increasing the amount of intake air flowing therethrough. Then, the intake air distributed to each of the divided intake passages 20 and 21 is
The first cylinder section including the first, second and third cylinders is supplied via the surge tank 18 and the branch passages 11 to 13, and the second cylinder part is supplied via the second surge tank 19 and the branch passages 14 to 16. The second cylinder section includes the fourth, fifth, and sixth cylinders, respectively.

Therefore, as shown in a characteristic diagram in which the horizontal axis represents the throttle opening θ and the vertical axis represents the effective intake passage cross-sectional area S, for example, the third
If the throttle passage section 28 is not provided and the accelerator pedal is slightly depressed, the first throttle valve 3 for the segmented intake passage section 20
1 and the second throttle valve 32 for the segmented intake passage section ₂₁ are opened, the first throttle valve 31 and By the time the opening degree of the second throttle valve 32 reaches the angle θ ₁ , the effective intake passage cross-sectional area S rapidly increases from 0 to S ₂ as shown by the curve Y, and the segmented intake passage However, the amount of intake air that flows through 20 and 21 and is guided to the first and second cylinder sections, respectively, increases rapidly.
In this example, from the time when the third throttle valve 33 is fully closed until its opening reaches the angle θ ₁ , the effective intake passage cross-sectional area S is as shown by the curve U. The amount of intake air that flows through the divided intake passages 20 and 21 and is guided to the first _and second cylinder sections is gradually increased. As a result, sudden fluctuations in engine torque do not occur.

On the other hand, when the amount of depression of the accelerator pedal is increased in order to increase the engine output and the rotation angle of the rotating shaft 38 of the third throttle valve 33 is set to an angle θ ₁ or more, as shown in FIG. 4B, Then, the fan-shaped fixing portion 38b of the rotating shaft 38 comes into contact with the valve bodies 31a and 32a of the first and second throttle valves 31 and 32, and rotates them integrally in the direction shown by the white arrow R, As a result, the third throttle valve 3
3, the first and second throttle valves 31 and 32 are opened. Therefore, the intake air from the common intake passage section 30 is transferred to the third throttle passage section 2.
In addition to 8, an effective intake passage with a large cross section is formed by opening the first and second throttle valves 31 and 32 in the first and second throttle passages 26 and 27, which have large diameters. The air is guided to the divided intake passages 20 and 21 through the air, and is equally distributed to the divided intake passages 20 and 21, respectively.
Then, the intake air distributed to the divided intake passages 20 and 21 passes through the first surge tank 18 and the branch passages 11 to 13 to the first, second, and third intake passages.
Introduced into a first cylinder section including the cylinder, and into a second cylinder section including the fourth, fifth, and sixth cylinders via the second surge tank 19 and branch passage sections 14 to 16. become.

That is, in this case, the effective intake passage cross-sectional area S
However, the effective intake passage cross-sectional area in the third throttle passage section 28 changes as shown by curve U in FIG. 5, and the effective intake passage cross-sectional area of the first and second throttle passages changes as shown by curve V in FIG. It is the sum of the effective intake passage cross-sectional areas at portions 26 and 27, and increases sharply from _S1 as shown by curve X. Along with this, the divided intake passage sections 20 and 2
This means that the amount of intake air introduced into the first and second cylinder sections by increasing the amount of air flowing through the engine is rapidly increased, making it possible to respond to a request for an increase in engine output with good responsiveness.

In this example, the intake passage includes independent divided intake passage sections 20 and 21 having a predetermined capacity and first and second surge tanks 18 and 19.
are interposed, and from the first and second surge tanks 18 and 19, the ignition order is not consecutive.
Each branch passage section 11 to
Since the intake air is supplied through the cylinders 13 and 14 to 16, the dynamic effect of the intake air is utilized to efficiently supply intake air to each cylinder.

In the above example, the first, second, and third throttle valves 31, 32, and 33 are opened and closed by rotating coaxially with the rotation shaft 38 of the third throttle valve 33. However, the intake system for a multi-cylinder engine according to the present invention does not necessarily have to be configured in this way; for example, the first and second throttle valves 31 and 32 and the third throttle valve 33 may be configured separately. It may be opened and closed by rotating.

Furthermore, the third throttle passage section 28 does not necessarily need to be disposed between the first and second throttle passage sections 26 and 27 as in the above example; and 27 in parallel to distribute the intake air to the pair of segmented intake passages.

(Effects of the invention) As is clear from the above description, the intake system for a multi-cylinder engine according to the present invention provides a multi-cylinder engine with a plurality of cylinder sections each having at least one cylinder. Two segmented intake passages that communicate with separate cylinder sections and guide intake air to each cylinder section have first and second throttle valves that are simultaneously opened and closed to adjust the amount of intake air that flows through each segmented intake passage section. Accordingly, it is possible to efficiently supply intake air with a uniform intake amount according to the opening degree of each throttle valve to each cylinder, and also to provide the first and second throttle valves. In addition to this, a third throttle valve is provided which can guide intake air to each segmented intake passage without passing through these, and when the accelerator pedal is depressed,
First, the third throttle valve opens, and then the first and second throttle valves open simultaneously with a delayed valve opening timing, so that when the accelerator pedal is slightly depressed, The amount of intake air supplied to each cylinder from each segmented intake passage does not increase rapidly, and as a result, it is possible to suppress the occurrence of sudden fluctuations in engine torque caused by a sudden increase in the amount of intake air guided to each cylinder. Become.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a schematic configuration of the main parts of an example of an intake system for a multi-cylinder engine according to the present invention;
The figure is a cross-sectional view taken along the - line in FIG. 1, FIG. 3 is a cutaway perspective view showing a specific configuration example of a part of the example shown in FIG. 1, and FIGS. 4 A and B are the example shown in FIG. 1. FIG. 5 is a schematic cross-sectional view used to explain the operation of the first
FIG. 4 is a characteristic diagram used to explain the operation of the example shown in the figure. In the figure, 18 and 19 are first and second surge tanks, 20 and 21 are divided intake passages, 26, 2
7 and 28 are first, second and third throttle passage parts; 30 is a common intake passage part; 31, 32 and 3;
3 is a first, second, and third throttle valve; 36 and 37 are tubular rotating shafts; and 38 is a rotating shaft.

Claims (1)

[Scope of utility model registration request] first and second segmented intake passages each communicating with a separate cylinder section each containing at least one cylinder;
a first throttle passage that guides the intake air to the divided intake passage; and a second throttle that guides intake air to the second divided intake passage through a second throttle valve that is opened and closed at the same time as the first throttle valve. via a third throttle valve that is arranged in parallel with the passage section and the first and second throttle passage sections and is operated to open earlier than the opening timing of the first and second throttle valves, Intake air from the above first and second
an intake system for a multi-cylinder engine, comprising: a third throttle passage section which is distributed to divided intake passage sections;