JPH07197823A - Intake air control device of v-type multi-cylinder engine - Google Patents

Abstract

PURPOSE:To simplify the structure of the whole intake system by forming each intake passage in the shape of being extended diagonally upward first, and then curved downward, forming a short passage in the shape being extended downward from the opening at the lower end of the intake passage, and forming a long passage in the shape of being branched and extended in the direction of the corresponding cylinder in the middle of the short passage. CONSTITUTION:Each merging passage 21a is formed in an approximately U-shape which is first extended diagonally upward and then curved downward, and a short passage 26 is formed in a shape which is extended downward from the opening of the lower end of downward curved and extended part 21b of the merged passage 21a by the distance of about the diameter, and a long passage 25 is formed in the shape which is branched and extended in the direction of the corresponding cylinder in the middle of the short passage 26. The short passage 26 is of the shape where the opening of the lower end of the merged passage 21a is slightly extended downward without change, and the air flow passing through the passage 21a made of synthetic resin from the short passage becomes smooth. In addition, the surge space can be increased while a surge tank 22 is made compact by constituting the surge space with the upper side communicating space B located on the upper side of the long passage and the lower side communicating space C located on the lower side of the long passage 25.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake control device for a V-type multi-cylinder engine, and more particularly, when the intake passage length is variably controlled according to the operating condition of the engine, or the occurrence of tumble is variably controlled. The present invention relates to the improvement of the intake passage structure and the passage length switching valve arrangement structure or the tumble switching valve arrangement structure.

[0002]

2. Description of the Related Art In order to increase the amount of intake air and increase the output and torque over a wide engine speed range, the intake passage length is set to a value that provides an inertia supercharging effect according to the engine speed. It is known that variable control is effective. When such variable intake passage length control is adopted in a V-type engine, it is common to arrange an intake system including a long passage, a short passage, and a switching valve therefor in a V-bank internal space (Japanese Patent Laid-Open No. 2004-242242). JP-A-61-255215, JP-A-62-851
(See Japanese Patent Publication No. 18). Further, it is known that it is effective to generate a vertical vortex (tumble) in the intake air flow introduced into the cylinder in order to improve the combustibility particularly in the low engine speed range.

[0003]

When the intake passage length variable control and tumble generation variable control described above are adopted in a V-type multi-cylinder engine having a large number of cylinders, depending on the arrangement structure of the intake system. For example, the structures of the merging passage, the long passage, the short passage, and the surge tank are complicated, and if the surge tank is made compact, there is a concern that the flow resistance of the air flowing in the tank increases.

The present invention has been made in view of the above circumstances, and provides a V-type multi-cylinder engine in which a large number of cylinders are arranged in a V shape with variable intake passage length control and tumble generation variable control. It is an object of the present invention to provide an intake control device which, when adopted, can prevent the structure of the intake system from becoming complicated and can reduce the flow resistance of air while making the surge tank compact.

[0005]

According to a first aspect of the present invention, a plurality of cylinders are arranged so as to form a V bank, and an intake valve opening of each cylinder is led to an inner wall of the V bank of a cylinder head through an intake port. In an intake control device for a V-type multi-cylinder engine in which an intake system connected to the intake port is arranged in a V bank, the intake system is obliquely upward in the V bank from an external connection port of each intake port. Each cylinder intake passage extending from the upper end portion thereof and curving downward, a short passage extending further downward from a lower end opening of each intake passage, and a branch from the corresponding cylinder side of the short passage extending in the corresponding cylinder direction. A long passage that is longer than the short passage, a surge tank that encloses the long passage and the short passage from below and forms a space of a predetermined volume with the intake passage, and a passage length switch that opens and closes each short passage. With valve It is characterized in that.

According to a second aspect of the present invention, in the first aspect, the respective intake passages for the respective cylinders are arranged in parallel so that the axes of the obliquely upward inclined portions of the respective passages intersect a straight line parallel to the crankshaft. And a tumble state in which one valve shaft that penetrates each of the intake passages in the crankshaft direction and a valve plate that is fixed to the valve shaft for each of the intake passages are used to actively generate the tumble. It is characterized in that a tumble switching valve for switching between a non-tumble state that is generated non-positively is disposed near a connecting portion between the intake passage and the intake port. It should be noted that non-aggressive generation does not mean that tumble is not generated at all. For example, although the intake flow is not controlled by rotating the tumble switching valve,
This means that tumble is generated to the extent that it occurs depending on the shape of the intake port.

According to a third aspect of the present invention, in the first or second aspect, the surge tank and the intake passages are formed.
An upper space surrounded by the lower curved portions of the left and right intake passages and a long passage, and a lower space surrounded by the long passage and the surge tank, which communicate with each other in the crankshaft direction. The upper space and the lower space are communicated with each other by a bypass space formed in the surge tank.

According to a fourth aspect of the present invention, in any one of the first to third aspects, the opening of the short passage is directed toward the crankshaft, and the opening of the long passage is directed in a direction opposite to the crankshaft and is short. It is characterized in that it is located farther from the crankshaft than the opening of the passage.

[0009]

According to the intake control device for a V-type multi-cylinder engine according to the present invention, each intake passage extends obliquely upward and is curved downward, and the short passage extends from the lower end opening of the intake passage. Since it has a shape extending downward and a long passage branched and extended from the middle of the short passage in the corresponding cylinder direction, the intake system as a whole has an extremely simple shape, and the structure of the entire intake system is simple. Is.

Further, since the short passage is formed by extending the lower end opening of the intake passage slightly downward as it is, the flow when passing through the intake passage from the short passage is smooth,
The flow resistance of air is reduced, and in particular, a large amount of air required when the engine rotates at high speed can be introduced without any trouble. Since the long passage has many bends, the flow resistance is larger than that of the short passage, but the long passage is originally used in an operating range where the engine has a relatively small amount of air at low speed rotation. Therefore, there is almost no problem.

According to the second aspect of the present invention, the intake passage for each cylinder is arranged such that the axis of the intake passage for the cylinder intersects a straight line parallel to the crankshaft. Therefore, each intake passage is on a straight line parallel to the crankshaft. Are arranged in parallel. Therefore, the tumble switching valve can be constituted by one valve shaft penetrating each of the intake passages and the valve plate of each intake passage, and the structure of the intake passage and the structure of the tumble switching valve are simple. is there.

According to the third aspect of the present invention, the downward curved portions of the intake passages for the left and right cylinders and the long passage are provided as a crankshaft-direction communication space constituted by the surge tank and the intake passages. Since the tunnel-shaped upper space surrounded by is also used, the surge tank can be made compact while the communication space in the crankshaft direction can be enlarged, and the flow resistance of the air flowing in the crankshaft direction in the space can be reduced.

Further, according to the invention of claim 4, the opening of the short passage is directed to the crankshaft side, and the opening of the long passage is directed in the opposite direction to the crankshaft.
The opening of the short passage opens to the lower space, and the opening of the long passage opens to the upper space. Therefore,
Regardless of which state the passage length switching valve is switched to, the air flow becomes smooth and the flow resistance from this point can be reduced.

[0014]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 9 are views for explaining an intake control device for a V-type multi-cylinder engine according to an embodiment of the present invention, FIG. 1 is a schematic front view of the engine of the present embodiment, and FIG. 2 is a view of the device of the present embodiment. Sectional front view, FIG. 3 is a plan view of the engine of this embodiment, FIG. 4 is a sectional view taken along line IV-IV of FIG. 3, and FIG. 5 is VV of FIG.
6 is a front view of the tumble switching valve, and FIGS.
[Fig. 3] is a schematic diagram for explaining the operation of the apparatus of this embodiment.

In the figure, 1 is a water-cooled 4-cycle V-type 8
The engine 1 is a cylinder engine, and the engine 1 has an oil pan 3 that forms a lower portion of the crank chamber connected to a lower mating surface of a skirt portion 2a that forms an upper portion of the crank chamber of the cylinder block 2.
The left and right cylinder heads 4 and 5 are connected to the mating surfaces of the left and right cylinder portions 2b and 2c forming the V bank of the cylinder block 2 by head bolts, and the left and right cylinder heads 4 and 5 are connected.
It has a structure in which the left and right head covers 6 and 7 are attached to the upper mating surface of 5. The engine of this embodiment includes the left and right cylinder parts 2b and 2c, the left and right cylinder heads 4, 5, and 5.
Since the left and right head covers 6 and 7 and the valve operating mechanism arranged inside are left-right symmetric, the following description and illustration will be made only for either left or right.

Four cylinder bores (cylinders) 2d are formed in parallel in each of the cylinder portions 2b and 2c, and a piston 8 slidably inserted in each cylinder bore 2d is connected through a connecting rod 9. It is connected to the crankshaft 10.

On the block-side mating surfaces 4a, 5a of the left and right cylinder heads 4, 5, there are provided four combustion recesses 11 each forming a combustion chamber.
1, three intake valve openings 11a to 11c and two exhaust valve openings 11d and 11e are formed. The exhaust valve openings 11d and 11e are opened and closed by an exhaust valve 12, and the exhaust valves 12 are opened and closed by an exhaust cam shaft 13. The intake valve openings 11a, 11b, 11c are opened and closed by intake valves 14a, 14b, 14a, respectively.
The intake cam shaft 15 opens and closes a and 14b.

The exhaust valve openings 11d and 11e are led out to the outer wall of the bank of each cylinder head 4 and 5 by one exhaust port 16, and the exhaust manifold 17 is provided in the external connection opening 16a of each exhaust port 16. It is connected.

The intake valve openings 11a to 11c are led out to the inner wall of each bank of the cylinder heads 4 and 5 through the intake port 18. An intake unit 19 is connected to the external connection opening 18a of the intake port 18. The intake unit 19 includes the left and right cylinder portions 2b, 2c,
The shape is set so as to fill the V bank space A formed by the left and right cylinder heads 4 and 5 and the left and right head covers 6 and 7. The intake unit 19 includes the left and right valve bodies 20 connected to the external connection opening 18a.
a, 20b, and a confluence passage block 21 arranged in an arch shape between the valve bodies 20a, 20b.
And a branch passage block 32 suspended below the merging passage block 21 and a surge tank 22.

The connection mating surfaces of the external connection openings 18a of the left and right cylinder heads 4 and 5 are formed so as to be flush with each other and parallel to the crankshaft.
Reference numeral b is a cast product made of an aluminum alloy, which has a flat plate shape.
In the left and right valve bodies 20a and 20b, a tumble switching valve 23 in which a valve plate 23b is fixed for each cylinder on a single valve shaft 23a extending parallel to the crankshaft 10.
Is provided. The valve plate 23b is formed with a notch 23c located outside the V bank when the valve plate 23b is rotated to the fully closed position. Therefore, when the intake port 18 is closed by the valve plate 23b, the intake air flows unevenly toward the top wall 18b side of the intake port 18, is introduced while being directed in the axial direction from the cylinder center side, and tumble is likely to occur. There is.

Further, one fuel injection valve 24 is attached to each of the valve bodies 20a and 20b so as to be substantially vertical, one for each cylinder. Each of the fuel injection valves 24 is located substantially on the center line of the intake port 18 when viewed from above,
The fuel injection port is directed to each of the intake valve openings 11a to 11c.

The merging passage block 21 is an aluminum alloy casting product in which the merging passages (intake passages) 21a for the left and right cylinders are arranged in parallel so as to overlap in the crankshaft direction. Each of the merging passages 21a includes the valve body 2
After extending from 0a or 20b to the inside of the V bank space A obliquely inward and upward, it is curved and extends downward from a position closer to the opposing cylinder side. Further, an upper communication space B extending in the crank axis direction in a tunnel shape is formed by the lower curved extension parts 21b, 21b for the left and right cylinders of the merging passage block 21 and a long passage 25 described later. . In addition, the downward curved extensions 21b, 21b
The lower end surface of the is formed flush with the valve body connection surface, thereby improving machinability.

Incidentally, the valve bodies 20a, 20b.
Can also be formed integrally with the merge passage block 21, and the merge passage in the claims is:
This is a concept including the passage in the valve body. In this embodiment, the valve body and the confluent passage block 21 are formed separately so as to simplify the mold structure.

The branch passage block 32 is provided in the case 32a having a rectangular shape in a plan view, and the left and right downward curved extension portions 21 are provided.
It is an aluminum alloy casting product in which a short passage 26 formed by extending b downward as it is and a long passage 25 branched and extended from the middle of the short passage 26 to the cylinder side are integrally formed.

The short passage 26 is set to have the same length as the diameter of the long passage 25 and a larger diameter than this. Therefore, the opening 26a of the short passage 26 is located on the side edge of the branch passage block 32 on the opposite cylinder side and near the bottom surface of the long passage 25, and toward the crankshaft 10 side, that is, the lower side described later. It opens to the communication space C side. Further, the long passage 25 is located substantially in the center of the branch passage block 32, and is slightly curved upward, and its opening 25a faces the side opposite to the crankshaft 10, that is, the upper communication space B side. It is open. Further, the tip end of the long passage 25 is located at a position slightly apart from the side wall of the case 32a on the corresponding cylinder side, and the space created thereby communicates the upper communication space B with the lower communication space C described later. It is a bypass space D.

Here, the length measured along the passage axis from the opening 26a of the short passage 26 to each of the intake valve openings 11a to 11c is such that an inertia supercharging effect can be obtained in a high speed rotation range of, for example, 4600 rpm or more. Is set to.
Further, the length measured along the passage axis from the opening 25a of the long passage 25 to each of the intake valve openings 11a to 11c is such that an inertia supercharging effect can be obtained in a medium to low speed rotation range of less than 4600 rpm. It is set.

In each of the short passages 26 for the left and right cylinders, passage length switching valves 27 for opening and closing the passages are provided. The passage length switching valve 27 penetrates the left and right short passages 26 and is inserted parallel to the crankshaft.
7a and a valve plate 27 for each short passage fixed to the valve shaft 27a. The valve shafts 27a are parallel to the valve shafts 23a of the left and right tumble switching valves 23 described above. As shown by the solid line in FIG. 2, when the short passage is closed, the valve plate 27b is positioned obliquely so as to be continuous with the bottom surface of the long passage 25, thereby reducing the flow resistance of intake air. There is.

The surge tank 22 is an aluminum alloy cast product having a bowl-shaped cross section which bulges downward, and a connecting flange 22b having an upper end opening is connected to a lower end opening of the branch passage block 32. An air inlet 22c is formed at one end of the surge tank 22 in the crankshaft direction. The throttle body 30b is provided in the air inlet 22c.
A throttle valve 30 in which a pair of valve plates 30a is rotatably arranged therein is connected.

By installing the surge tank 22, the surge tank 22, the branch passage block 32, and the merging passage block 21 form a space having a sufficient volume to function as a surge tank (hereinafter referred to as a surge space). ing. The surge space means a space having a sufficient volume to open the pressure wave generated by opening and closing the intake valve opening by the intake valve to the atmosphere.

The surge space includes the upper communication space B, the long passage 25, and the surge tank 2.
Lower communication space C surrounded by 2 and extending in the crankshaft direction
And the spaces B and C communicate with each other through the bypass space D. Therefore, the air introduced into the surge space from the air introduction port 22c of the surge tank 22 flows in the crankshaft direction through both the lower communication space C and the upper communication space B (FIG. 4). See the arrow).

A diaphragm valve 28 as an actuator is arranged at the outward protruding end of the valve shaft 27a of the intake passage length switching valve 27, and the output shaft 28a of the diaphragm valve 28 is fixed to the valve shaft 27a. Is connected to the arm. The diaphragm valve 28 is supported by the boss portion 21g of the confluence passage block 21, which is the same member in which the intake passage length switching valve 27 is arranged, and the valve shaft 23a of the tumble switching valve 23. The diaphragm valve 29 connected to is supported by the valve bodies 20a and 20b which are the same members as the tumble switching valve 23 is arranged in. Therefore, it is possible to avoid an assembly error between each switching valve and the diaphragm valve, and it is possible to smoothly perform the opening / closing operation.

The left and right intake passage length switching valves 27 are also provided.
The diaphragm valves 28, 28 are arranged at a high place by inclining toward the outside of the V bank space A and extending the output shaft 28a, and the diaphragm valves 29 for the left and right tumble switching valves 23 are arranged. , 29 are arranged outside the diaphragm valves 28, 28. As a result, a relatively large space is formed between the left diaphragm valve 29, 28 and the right diaphragm valve 29, 28, and a relatively large throttle valve 30 can be arranged in the space without any trouble. Further, since the throttle valve 30 is located at the center of the V bank, it is not necessary to bend the introduction passage, and therefore the introduction resistance of air can be reduced.

Next, the function and effect of the apparatus of this embodiment will be described. In FIG. 7, reference numeral 40 denotes an ECU that controls the opening and closing of the tumble switching 23, the intake passage length switching valve 27, the throttle valve 30a, etc., which indicates the engine operating state such as the throttle valve opening a and the engine speed b. A signal is input and the tumble switching signal A and the passage length switching signal B are output according to the operating state of the engine.

First, as shown in FIG. 6, the tumble switching valve 23 is put in the tumble state in the diaphragm valve 29 in the low speed low load operation region where the engine speed is, for example, 2600 rpm or less and the throttle opening is, for example, about 10%. The tumble switching signal A is supplied to the tumble switching valve 23, whereby the tumble switching valve 23 is rotated to the tumble position, that is, the closed position where only the top wall side of the intake passage 18 is open (the position shown in FIG. 2). As a result, the intake air flows unevenly toward the top wall of the intake passage 18, is introduced axially from the vicinity of the cylinder axis, and tumble is generated.

At this time, the diaphragm valve 28 is supplied with the switching signal B for making the passage length changeover valve 27 make the passage length longer, whereby the passage length changeover valve 27 is shortened as shown in FIG. The passage 26 is closed, and the intake air is introduced into the cylinder through the long passage 25. As a result, the intake passage length becomes a length that provides the effect of inertia supercharging in the low speed rotation range.
It is possible to secure a sufficient intake amount while generating the tumble.

Further, as shown in FIG. 8, the tumble switching valve 23 is fully opened, that is, in the non-tumble position, in an engine speed of 2600 to 4600 rpm and a throttle opening of, for example, about 40% in a medium speed rotation and medium load range. On the other hand, the passage length switching valve 27 keeps the passage length long.
As a result, the throttle for generating tumble is released, and a larger intake amount is secured.

Further, as shown in FIG. 9, in the high-speed high-load operating region where the engine speed is, for example, 4600 rpm or more and the throttle opening is substantially fully opened, the passage length switching valve 27 opens the short passage 25, so Most of the air is introduced into the cylinder through a short passage having a length capable of obtaining an inertia supercharging effect in the high speed rotation range, and a large amount of intake air is secured in the high speed rotation range.

In this embodiment, each of the merging passages 21a has a substantially U-shape that extends obliquely upward and then curves downward.
The short passage 26 is provided with the downward curved extension 2 of the confluence passage 21a.
Since the long passage 25 has a shape extending downward from the lower end opening of 1b by about the diameter thereof and the long passage 25 is branched and extended in the cylinder direction, the entire intake passage including the merging passage block 21 and the branch passage block 32 is formed. Has an extremely simple shape, and the structure of the entire intake passage is simple.

Further, since the intake passage is divided into the confluence passage block 21 and the branch passage block 22, the mold structure in the case of manufacturing by casting is simple, and as a result, the manufacturing cost can be reduced. Incidentally, when both the blocks 21 and 22 are integrally formed, it is extremely difficult to perform a normal die casting, but in the present embodiment, the normal die casting can be performed by dividing the above into two.

Since the short passage 26 is formed by extending the lower end opening of the merging passage 21a slightly downward as it is, the flow from the short passage 26 through the merging passage 21a is smooth, and the air flow is small. Flow resistance is reduced, and a large amount of air required especially at high engine speed can be introduced without any trouble. It should be noted that since the curved portion of the long passage 26 is increased by one place, the flow resistance becomes larger than that of the short passage 26, but the long passage 25 has a relatively small amount of air when the engine rotates at a low speed. Since it is used in some cases, there is almost no problem.

In this embodiment, the merging passage 21 for each cylinder is also provided.
Since a is arranged so that its axis intersects with a straight line parallel to the crankshaft, the respective merge passages 21a are arranged in parallel on a straight line parallel to the crankshaft. Therefore, the left and right tumble switching valves 23 are passed through the merging passages 1
It can be constituted by a book valve shaft 23a and a valve plate 23b for each merging passage, and the structure of the tumble switching valve 23 is also simple.

Further, since the surge space is constituted by the upper communication space B located above the long passage 25 and the lower communication space C located below, the surge tank 22 is compact and the surge is maintained. The space can be enlarged, and the flow resistance of the air flowing in the space in the crankshaft direction can be reduced. When the passage length switching valve 27 is closed, the short passage 2
The space from the valve plate 27b of No. 6 to the opening 26a is a dead space that obstructs the flow of air in the crankshaft direction. However, in this embodiment, the dead space is small, and the flow resistance can be reduced also from this point.

Furthermore, the opening 26 of the short passage 26 is provided.
Since a is directed to the crankshaft 10 side and the opening 25a of the long passage 25 is directed in the opposite direction to the crankshaft 10, the opening 26a of the short passage 26 is connected to the lower communication space C.
The opening 25a of the long passage 25 is open to the upper communication space B. Therefore, no matter which state the passage length switching valve 27 is switched to, the air flow becomes smooth, and the flow resistance can be reduced also from this point.

Furthermore, in the present embodiment, when the tumble switching valve 23 is rotated to the tumble position in the low speed rotation range to generate tumble, the passage length switching valve 27 is switched to the long side so that the inertial force becomes excessive. Since the intake effect is obtained, it is possible to compensate for the decrease in the intake air amount due to the inflow resistance generated to generate the tumble with the inertia supercharging, and to generate the tumble to improve the combustion state and to obtain a sufficient intake air amount. It is possible to secure the output and avoid a decrease in output.

[0045]

As described above, according to the intake control device for a V-type multi-cylinder engine according to the first aspect of the present invention, each intake passage is formed to extend obliquely upward and then curved downward, and the short passage is formed as described above. A shape that extends downward from the lower end opening of the intake passage,
Since the long passage is branched and extended in the cylinder direction from the middle of the short passage, there is an effect that the structure of the entire intake system can be simplified.

Further, since the short passage is formed by extending the lower end opening of the intake passage slightly downward as it is, the flow from the short passage through the intake passage is smooth,
The flow resistance of air is reduced, and in particular, a large amount of air required when the engine rotates at high speed can be introduced without any trouble.

According to the second aspect of the present invention, the intake passage for each cylinder is arranged so that its axis intersects with a straight line parallel to the crankshaft. Therefore, each intake passage is on a straight line parallel to the crankshaft. Are arranged in parallel. Therefore, the tumble switching valve for the left and right cylinders can be configured by one valve shaft that penetrates each intake passage and the valve plate for each intake passage. The structure of this intake passage and the tumble switching valve This has the effect of simplifying the structure.

According to the invention of claim 3, the tunnel-shaped upper communication space surrounded by the downward curved portions of the intake passages and the long passage is also used as the surge space, so that the surge tank is made compact. However, the surge space can be enlarged, and the flow resistance of the air flowing in the crankshaft direction in the space can be reduced.

Further, according to the invention of claim 4, since the opening of the short passage is directed to the crankshaft side and the opening of the long passage is directed in the direction opposite to the crankshaft,
The opening of the short passage opens to the lower communication space, and the opening of the long passage opens to the upper communication space.
Therefore, no matter which state the passage length switching valve is switched to, the air flow becomes smooth, and from this point also the flow resistance can be reduced.

[Brief description of drawings]

FIG. 1 is a front view of an engine including an intake control device according to an embodiment of the present invention.

FIG. 2 is a sectional front view of the engine of the embodiment (II-I in FIG. 3).
It is a sectional view taken along line I).

FIG. 3 is a plan view of the engine of the embodiment.

FIG. 4 is a sectional side view of the engine of the above embodiment (IV-I in FIG. 3).
It is a sectional view taken along line V).

FIG. 5 is a plan view (a view taken along the line VV in FIG. 2) of the engine of the above-described embodiment with a confluent passage block removed.

FIG. 6 is a front view of a tumble switching valve of the engine of the first embodiment.

FIG. 7 is a schematic diagram for explaining the operation of the engine of the embodiment.

FIG. 8 is a schematic diagram for explaining the operation of the engine of the embodiment.

FIG. 9 is a schematic diagram for explaining the operation of the engine of the embodiment.

[Explanation of symbols]

 1 V type multi-cylinder engine 2d Cylinder bore (cylinder) 4,5 Cylinder head 10 Crankshaft 11a-11c Intake valve opening 18 Intake port 21a Confluence passage (intake passage) 21b Lower curved part 22 Surge tank 23 Tumble switching valve 23a Valve shaft 23b Valve plate 25 Long passage 25a Long passage opening 26 Short passage 26a Short passage opening 27 Passage length switching valve A V Bank space B Upper communication space C Lower communication space D Bypass space

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location F02M 35/104

Claims (4)

[Claims] 1. A plurality of cylinders are arranged to form a V bank, an intake valve opening of each cylinder is led out to an inner wall of a V bank of a cylinder head through an intake port, and an intake system connected to the intake port is a V bank. In the intake control device for a V-type multi-cylinder engine, each of the intake systems extends obliquely upward in the V bank from the external connection port of each intake port and extends downward from the upper end of the intake system. Cylinder intake passage,
A short passage extending further downward from the lower end opening of each intake passage, a long passage branched from the corresponding cylinder side of the short passage and extending in the corresponding cylinder direction, a long passage longer than the short passage, the long passage and the short passage. Intake control of a V-type multi-cylinder engine, comprising: a surge tank that encloses the passage from below and forms a space of a predetermined capacity with the intake passage; and a passage length switching valve that opens and closes each of the short passages. apparatus. 2. The intake passage for each cylinder according to claim 1, wherein the intake passages for each cylinder are arranged in parallel so that an axis of an obliquely upwardly inclined portion of each passage intersects a straight line parallel to a crankshaft,
A vertical vortex (a vertical vortex that flows into the cylinder in the cylinder axis direction) is composed of one valve shaft penetrating each intake passage in the crankshaft direction and a valve plate fixed to the valve shaft for each intake passage. Hereinafter, a tumble switching valve for switching between a tumble state in which a tumble) is positively generated and a non-tumble state in which a tumble is not positively generated is disposed in the vicinity of a connection portion between the intake passage and the intake port. An intake control device for a V-type multi-cylinder engine. 3. The space defined by the surge tank and each of the intake passages, which communicates with each other in the crankshaft direction, according to claim 1 or 2, wherein the downward curved portions of the intake passages for the left and right cylinders are provided with a long passage. And a lower space surrounded by the long passage and the surge tank, and the upper space and the lower space are communicated by a bypass space formed in the surge tank. An intake control device for a V-type multi-cylinder engine. 4. The crank passage according to claim 1, wherein the opening of the short passage is directed toward the crankshaft, the opening of the long passage is directed in a direction opposite to the crankshaft, and the crank is opened from the opening of the short passage. An intake control device for a V-type multi-cylinder engine, which is located at a position far from the axis.