JP4581314B2 - Multi-cylinder engine intake system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an intake device for a multi-cylinder engine.
[0002]
[Prior art]
Conventionally, the intake passage is composed of a low-speed passage and a high-speed passage, and a switching valve is provided at the joint portion of both passages, and the switching passage is used to switch the length of the intake passage according to the engine speed, and during the intake stroke. The intake volume efficiency is improved by the so-called intake inertia effect obtained by synchronizing the frequency of the pressure change (engine speed) caused by the lowering of the piston with the natural frequency of the intake system determined by the intake passage length and cylinder volume. It is known to increase output. (For example, see Japanese Patent Publication No. 5-78651)
In an engine using such an intake inertia effect, in order to expand the output improvement region by using this intake inertia effect, the high-speed passage length is made shorter so that it synchronizes with this natural frequency even in a higher rotation range. There is a demand to do. In order to satisfy such a requirement, it is desirable that the junction where the low-speed passage and the high-speed passage join are located as close to the engine as possible on the downstream side of the intake passage. This is because the high-speed passage length from the merging portion to the engine can be shortened and the overall length of the high-speed passage can be shortened by positioning the merge portion as downstream as possible from the intake passage.
It is also known to improve acceleration response by a so-called multiple throttle valve in which a throttle valve is arranged for each cylinder so that the throttle valve is close to the engine. In such a multiple throttle valve, there is a demand to position the throttle valve on the downstream side of the intake passage as close to the engine as possible in order to further improve the acceleration response. This is because the intake passage volume downstream of the throttle valve can be reduced and acceleration response can be improved.
[0003]
[Problems to be solved by the invention]
However, when the latter multiple throttle valve is applied to the engine using the intake inertia effect of the former, as described above, both the switching valve for switching the passage length and the throttle valve are as downstream as possible. Although there is a demand to position the valves on the side, the valves are arranged in series even if trying to place both valves as downstream as possible in the intake passage, so one of the valves is located upstream of the intake passage (in the direction away from the engine). It must be located. Therefore, for the valve located on the upstream side, the passage length of the high-speed passage is increased or the volume downstream of the intake passage is increased, the intake inertia effect or acceleration response is impaired, and both requirements cannot be satisfied. There is a problem. Moreover, there is a problem that the number of valves increases and the number of parts to be assembled increases.
[0004]
The present invention has been made in consideration of the above-described problems, and an object of the present invention is to provide an intake device for a multi-cylinder engine that can achieve both an intake inertia effect and an acceleration response without increasing the number of engine assembly parts. Is to provide.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides the following solution as a solution. That is, in the first configuration of the present invention,
An independent intake passage having a low speed passage with a long passage length and a high speed passage with a short passage length is provided for each cylinder, and each upstream end of the low speed passage and the high speed passage of each independent intake passage is an intake air collecting portion. And the downstream ends of the low-speed passages and the high-speed passages of the independent intake passages are joined to each other through a common intake passage that serves as both the low-speed passage and the high-speed passage after being joined at the junction. Intake of a multi-cylinder engine connected to the intake port of the multi-cylinder engine provided with a switching valve that switches the communication state of the low-speed passage and the high-speed passage to the common intake passage according to the operating state. In the apparatus, the switching valve is formed in a substantially L-shape, and a plate that operates independently of the switching valve within a substantially L-shaped range of the switching valve coaxially with the valve shaft of the switching valve. Equipped with a throttle valve That,
It is like that.
According to the first configuration of the present invention, since the switching valve and the throttle valve are arranged coaxially, both valves can be arranged on the downstream side of the intake passage, and the intake inertia effect and the acceleration response can be reduced. Both can be achieved. Further, the valve shaft can be shared, and an increase in the number of engine assembly parts can be suppressed. Further, since the switching valve is L-shaped and the throttle valve is operated within the L-shaped range, both valves can be operated without causing interference between the switching valve operation and the throttle valve operation.
[0006]
Further, in the second configuration of the present invention, the merging portions are sequentially arranged in the cylinder arrangement direction so that the merging portions overlap each other when viewed from one end side in the cylinder arrangement direction, and are formed on the passage walls in the merging portions. The valve shaft of the switching valve extends in the cylinder arrangement direction.
It is like that.
According to the second configuration of the present invention, by disposing the valve shaft on the passage wall, the valve shaft is not positioned in the intake passage, and the intake resistance can be reduced.
[0007]
In the third configuration of the present invention, the low speed passage extends from the lower side of the engine toward the upper side and then joins the merging portion, and the high speed passage extends from the upper side of the engine toward the lower side. After that, the common intake passage is bent from the merge portion to the engine lower side and connected to each intake port to generate a vertical vortex in the air flowing into the combustion chamber. ,
The throttle valve is located substantially along the upper passage wall extension line of the low-speed passage when the throttle valve is substantially fully opened in a state where the high-speed passage is closed and the low-speed passage is opened. The tip is bent downward,
It is like that.
According to the third configuration of the present invention, when the low-speed passage is in communication, the throttle valve is located along the upper passage wall extension line of the low-speed passage when the throttle valve is fully opened. As a result, the air flow from the low-speed passage can be smoothly guided sequentially to the merging portion, the common intake passage, and the intake port. Further, since the tip of the throttle valve is bent downstream, the air flow can be smoothly guided downward in the engine, and longitudinal vortex generation can be promoted.
[0008]
In the fourth configuration of the present invention, the throttle valve may include a fully closed position and a fully opened position of the throttle valve in accordance with switching of the communication state of the low speed passage and the high speed passage with respect to the common intake passage of the switching valve. Throttle valve control means for switching the relationship with the position and switching the operating direction of the throttle valve is provided.
It is like that.
According to the fourth configuration of the present invention, the fully closed position, the fully opened position, and the operating direction of the throttle valve can be appropriately set regardless of whether the passage communicated with the common intake passage is the low speed passage or the high speed passage. Intake amount adjustment by the throttle valve is appropriately performed.
[0009]
Further, in the fifth configuration of the present invention, an independent intake passage having a low speed passage having a long passage length and a high speed passage having a short passage length is provided for each cylinder, and the low speed passage of each of the independent intake passages and Each upstream end of the high speed passage is connected to an intake air collecting portion, and each of the low speed passages of the independent intake passages and each downstream end of the high speed passage is joined at the junction, and then the low speed passage and the high speed passage Are connected to the intake port of each cylinder via a common intake passage that also serves as the engine, and the connecting portion switches the communication state of the low-speed passage and the high-speed passage to the common intake passage according to the operating state. In an intake device of a multi-cylinder engine provided with a switching valve,
The switching valve is composed of a cylindrical rotary valve, and a throttle valve composed of a cylindrical rotary valve that operates independently of the switching valve is provided coaxially with the valve shaft of the switching valve. ,
It is like that.
According to the fifth configuration of the present invention, there is no need to switch the fully closed position, the fully opened position and the operation direction when switching the intake passage as in the case of the plate-like throttle valve, and the throttle valve operating direction is changed when the intake passage is switched It is possible to suppress the air amount fluctuation accompanying the. Further, since the switching valve and the throttle valve are integrated into a double rotary valve, the quality control of both valves becomes easy.
[0010]
In the sixth configuration of the present invention, the low speed passage extends from the lower side of the engine toward the upper side and then joins the merging portion, and the high speed passage extends from the upper side of the engine toward the lower side. And then joined to the joining portion, the common intake passage is curved downward on the engine and connected to each intake port to generate a vertical vortex in the air flowing into the combustion chamber,
The opening direction of the throttle valve is set so as to gradually open from the upper side to the lower side in the junction.
It is like that.
According to the sixth configuration of the present invention, even when the throttle valve opening is small, the flow of air above the merging portion is allowed. Therefore, the low-speed passage, the merging portion, and the common intake passage that become the main flow of the air flow In addition, the upward flow in each passage of the intake port is always allowed, and longitudinal vortex generation can be promoted regardless of the throttle opening.
[0011]
Further, in the seventh configuration of the present invention, an independent intake passage having a low speed passage having a long passage length and a high speed passage having a short passage length is provided for each cylinder, and the low speed passage of each of the independent intake passages and Each upstream end of the high speed passage is connected to an intake air collecting portion, and each of the low speed passages of the independent intake passages and each downstream end of the high speed passage is joined at the junction, and then the low speed passage and the high speed passage Are connected to the intake ports of the cylinders via a common intake passage that also serves as an engine, and the joining portion communicates with the low-speed passage and the high-speed passage with respect to the common intake passage according to operating conditions. In an intake device of a multi-cylinder engine provided with a switching valve for switching,
A throttle valve that operates independently of the switching valve is provided on the same axis as the valve shaft of the switching valve.
It is like that.
According to the seventh configuration of the present invention, since the switching valve and the throttle valve are arranged coaxially, both valves can be arranged on the downstream side of the intake passage, and the intake inertia effect and the acceleration response can be reduced. Both can be achieved. Further, the valve shaft can be shared, and an increase in the number of engine assembly parts can be suppressed.
[0012]
Further, in the eighth configuration of the present invention, the low speed passage is bundled at the intake air collecting portion so that the low speed passage lengths from the intake air collecting portion to the merging portion are substantially the same.
It is like that.
First, if the intake passage lengths of the cylinders are not uniform, it will lead to the generation of intake noise and the deterioration of the intake distribution between the cylinders, so there is a demand for equalizing the intake passage lengths of the cylinders.
By the way, in order to drive the switching valve and the throttle valve of each cylinder with one shaft, it is necessary to extend the valve shaft in the cylinder arrangement direction, and for this purpose, a collecting portion where the switching valve and the throttle valve are arranged. When viewed from one end side in the cylinder arrangement direction, a parallel arrangement is required in which the merging portions overlap.
However, the distance from the merging section to the intake manifold becomes shorter as the merging sections move away from the engine (the space becomes narrower). Since restrictions on the passage arrangement such as the degree of curvature of the passages are increased, it is difficult to make the intake passage lengths of the cylinders uniform.
According to the eighth configuration of the present invention, since the switching valve and the throttle valve are arranged coaxially, both valves can be arranged as downstream as possible in the intake passage (being close to the engine). Can do). Therefore, the parallel arrangement in which the merging portions overlap with each other may be only in the vicinity of the downstream end of the intake passage. Accordingly, since the distance from the merging portion to the intake air collecting portion can be increased (because the space can be widened), the passage length can be bundled so as to be substantially uniform between the merging portion and the intake air collecting portion. It is possible to suppress the generation of intake noise due to the non-uniformity and to improve the intake distribution between the cylinders.
[0013]
【The invention's effect】
According to the present invention, it is possible to achieve both the intake inertia effect and the acceleration response without increasing the number of engine assembly parts.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
[0015]
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0016]
(First embodiment)
FIGS. 1-6 has shown the intake device regarding 1st Embodiment, and has shown the example applied to the intake manifold M of a 4-cylinder engine.
[0017]
In FIG. 1, which is a front view of the intake manifold M, the intake manifold M includes independent intake passages 1 to 4 provided for each cylinder, an intake manifold portion 5 on the upstream side, and an upstream side of the intake manifold portion 5. The surge tank 6 is provided.
As shown in FIG. 2 which is a perspective view of the intake air collecting portion 5 and the surge tank 6, the intake air collecting portion 5 has a width shorter than the width of the surge tank 6 in the lateral direction, and is formed substantially horizontally. From the upper side part 5a, the first oblique side part 5b gradually widening downward on both sides of the upper side part 5a, and the second oblique side part 5c gradually narrowing downward from the first oblique side part 5b It is formed.
[0018]
Each of the independent intake passages 1 to 4 is a plan view of the intake manifold M viewed from the upper side of FIGS. 1 and 1 and FIG. 4 is a sectional view taken along the line IV-IV of FIG. As shown in FIG. 2, the tank is composed of a low speed passage and a high speed passage. That is, the first low-speed passage 1a and the first high-speed passage 1b are connected to the first cylinder, and the second low-speed passage 2a and the second high-speed passage 2b are connected to the second cylinder. Are connected to the third cylinder, the third low-speed passage 3a and the third high-speed passage 3b, and the fourth cylinder is connected to the fourth low-speed passage 4a and the fourth high-speed passage. 4b is connected.
[0019]
As shown in FIG. 2, the upstream side of each passage is connected to the intake air collecting portion 5, and the first to fourth low speed passages 1 a to 4 a are connected to the side surface 5 d of the intake air collecting portion 5. The first high-speed passage 1b is connected to the connecting portion 1d formed in one first oblique side portion 5b, and the second and third high-speed passages 2b and 3b are formed in the upper side portion 5a. The fourth high-speed passage 4a is connected to the connection portion 4d formed in the other first oblique side portion 5b.
Further, the downstream side of each passage is a side view of the intake manifold M as viewed from one side of FIG. 1 (the left side in FIG. 1), and a cross-sectional view of the intake manifold M connected to the engine body. As shown in FIG. 6, after the low speed passages 1 a to 4 a and the high speed passages 1 b to 4 b are joined at the downstream junction 7, the common passage 8 formed separately from the intake manifold M is used. Is connected to the intake port 9 of each cylinder.
As shown in FIG. 4, the low-speed passages 1 a to 4 a have different curved shapes and degrees of curvature for the respective low-speed passages, and the passage length between the intake air collecting portion 5 and the merging portion 8 is different for each passage. Is set to be equal.
[0020]
1, 3, and 5, 10 is a motor for driving a throttle valve 12 described later, and 11 is a motor for driving a switching valve 13 described later.
[0021]
5 and 6, the low speed passages 1 a to 4 a are joined to the rear joining portion 7 extending from the lower side of the engine toward the upper side, and the high speed passages 1 b to 4 b are directed from the upper side of the engine to the lower side. After joining, it joins the joining part 7. From the merging portion 7, the common intake passage 8 is slightly curved upward, then again curved downward, and smoothly connected to the intake port 9 which is curved downward.
With such a passage configuration, when the low speed passages 1a to 4a are used, air flows in the order of the low speed passages 1a to 4a, the merging portion 7, the common intake passage 8 and the intake port 9, and flows into the combustion chamber 14. A vertical vortex is generated.
[0022]
A throttle valve 12 and a switching valve 13 are arranged at the junction 7.
Since the merging portion 7 is disposed in the common intake passage 8 disposed closer to the intake port 9 than the intake manifold M, the merging portion 7 and the valves 12 and 13 are as close as possible to the intake port 9 (engine). Be placed.
The throttle valve 12 is formed on a plate, and its tip is bent to the engine lower side, and the switching valve 13 is formed in a substantially L shape.
The drive shaft 12a of the throttle valve 12 is disposed in the merging portion wall 7a of the merging portion 7 and extends through the merging portion walls 7a of the merging portions 7 in the cylinder arrangement direction.
The drive shaft 13a of the switching valve 13 is disposed concentrically on the outer periphery of the drive shaft 12a of the throttle valve 12, and is disposed in the junction wall 7a of the junction 7 like the drive shaft 12a of the throttle valve 12. Each merging portion 7 extends in the cylinder arrangement direction through each merging portion wall 7a.
The throttle valve 12 and the switching valve 13 are operated independently by the motors 10 and 11, respectively.
[0023]
The throttle valve 12 is operated from fully closed to fully opened within the L-shape of the switching valve 13. For example, FIG. 6 shows a case where the throttle valve 12 is in the fully opened position with the low speed passages 1a to 4a being opened by the switching valve 13 and the high speed passages 4a to 4b being closed. 12 is opened according to various input signals such as the accelerator opening from the fully closed position indicated by the wavy line to the fully open position indicated by the solid line.
When the position of the switching valve 13 is switched from the above state, the low speed passages 1a to 4a are closed by the switching valve 13, and the high speed passages 1b to 4b are opened, the throttle valve 12 is in contrast to the above state. The fully closed position and the fully open position are reversed. That is, when the low speed passages 1a to 4a are opened, the position of the wavy line that is the fully closed position is the fully open position, and the position of the solid line that is the fully open position is the fully closed position. The operating direction is opposite to the above state.
Further, the throttle valve 12 is fully opened when the low speed passages 1a to 4a are used, as shown by a solid line in FIG. 6, so as to substantially follow the extension lines of the upper passage walls 1e to 4e of the low speed passages 1a to 4a. Is done.
[0024]
The switching valve 13 opens the low-speed passages 1a to 4a when the engine speed is low and closes the high-speed passages 1b to 4b. When the engine speed is high, the switching valve 13 closes the low-speed passages 1a to 4a and The position is controlled so as to open the passages 1b to 4b.
[0025]
Hereinafter, control of the throttle valve 12 and the switching 13 valve will be described with reference to FIGS.
[0026]
In FIG. 7, reference numeral 100 denotes an engine control unit (ECU) to which various sensor signals necessary for controlling the engine speed sensor 101, the throttle valve 12 such as the accelerator opening sensor 102, and the switching valve 13 are input. The
The motor 10 for driving the throttle valve 12 and the motor 11 for driving the switching valve 13 are controlled by an engine control unit (ECU) 100 as follows.
[0027]
(Throttle valve control)
In FIG. 8, in step S1, signals from various sensors such as the engine speed sensor 101 and the accelerator opening sensor 102 are read. In subsequent step S2, it is determined whether or not the switching valve 13 is in a low speed region that opens the low speed passages 1a to 4a and closes the high speed passages 1b to 4b. In step S2, when the engine speed is equal to or lower than a set speed (eg, 3000 rpm), the low speed region is determined. When YES is determined in the step S2, the process proceeds to a step S3 so as to set the throttle valve 12 to the low speed fully closed position. This low speed fully closed position is a position indicated by a wavy line in FIG. When it is determined NO in step S2, the process proceeds to step S4, and the throttle valve 12 is set to the high speed fully closed position. This high speed fully closed position is a position indicated by a solid line in FIG.
[0028]
In step S5, the target throttle valve opening is set according to the accelerator opening and the like, and in step S6, the motor 10 is driven according to the target throttle opening set in step 5. In step 5, the driving direction of the motor 10 is switched according to the fully closed position set in steps S3 and S4.
[0029]
(Switching valve control)
In FIG. 9, in step S10, signals from various sensors such as the engine speed sensor 101 and the accelerator opening sensor 102 are read. In step S20, it is determined whether or not the switching valve 13 is in a low speed region that opens the low speed passages 1a to 4a and closes the high speed passages 1b to 4b. In step S20, it is determined as a low speed region when the engine speed is equal to or lower than a set speed (eg, 3000 rpm).
[0030]
When YES is determined in step S20, the process proceeds to step S30, and the position of the switching valve 13 is controlled so as to open the low speed passages 1a to 4a and close the high speed passages 1b to 4b. When it is determined NO in step S20, the process proceeds to step S40 to control the position of the switching valve 13 so as to close the low speed passages 1a to 4a and open the high speed passages 1b to 4b.
[0031]
According to the first embodiment, the following effects can be obtained.
[0032]
By arranging the drive shaft 12a of the throttle valve 12 and the drive shaft 13a of the switching valve 13 on the same axis, both the valves 12 and 13 can be arranged on the downstream side of the intake passage, and the intake inertia effect and acceleration can be achieved. Compatibility with responsiveness can be achieved.
Further, the valve shafts 12a and 13a of both the valves 12 and 13 can be made common, and an increase in the number of engine assembly parts can be suppressed.
[0033]
Since the drive shaft 12a of the throttle valve 12 and the drive shaft 13a of the switching valve 13 are disposed in the merge portion wall 7a of the merge portion 7, the valve shafts 12a and 13a are not positioned in the intake passage. The intake resistance can be reduced.
[0034]
When the low-speed passages 1a to 4a are used, the throttle valve 12 is positioned along the extension line of the upper passage walls 1e to 4e of the low-speed passages 1a to 4a when the throttle valve 12 is fully opened. As a result, the air flow from the low-speed passages 1a to 4a can be smoothly and smoothly guided to the joining portion 7, the common intake passage 8 and the intake port 9.
Further, since the tip of the throttle valve 12 is bent toward the engine lower side, the air flow can be smoothly guided in the engine lower direction, and the generation of the vertical vortex can be promoted.
[0035]
Since the throttle valve 12 is switched between the fully closed position and the fully open position when the low speed passages 1a to 4a are used and when the high speed passages 1b to 4b are used, the state of the use passage is changed. Regardless, the amount of air can be adjusted appropriately by the throttle valve 12.
[0036]
(Second Embodiment)
The basic configuration of the second embodiment is the same as that of the first embodiment, and both the throttle valve 12 and the switching valve 13 are formed of a cylindrical rotary valve. Different from form.
Hereinafter, this different point will be described with reference to FIG.
FIG. 10 is a cross-sectional view corresponding to FIG.
[0037]
In the merging portion 7, a throttle valve 12 composed of a cylindrical rotary valve and a switching valve 13 composed of a cylindrical rotary valve are arranged.
The switching valve 13 is disposed concentrically on the outer periphery of the throttle valve 12 and is operated independently of the valves 12 and 13.
[0038]
The throttle valve 12 has an air inlet 12a, a low-speed air amount adjusting unit 12b, and a high-speed air amount adjusting unit 12c, and adjusts the air amount by rotating clockwise on the paper surface of FIG. It is like that. For example, when the low-speed passages 1a to 4a are used, the opening area of the air inlet 12a is gradually expanded from the upper side to the lower side of the junction 7 by rotating the low-speed air amount adjusting unit 12b clockwise. The amount of air is increased. In addition, when the high-speed passages 1b to 4b are used, the opening area of the air inlet 12a gradually increases from the upper side to the lower side of the junction 7 by rotating the high-speed air amount adjusting unit 12c clockwise. The amount of air is increased.
[0039]
The switching valve 13 has an air inlet 13a, a low-speed passage blocking portion 13b, and a high-speed passage blocking portion 13c. By rotating counterclockwise on the paper surface of FIG. The communication state between the low speed passages 1a to 4a and the high speed passages 1b to 4b with respect to the passage 8 is switched.
FIG. 10 shows a state where the high speed passages 1b to 4b are closed by the switching valve 13 and the low speed passages 1a to 4a are opened, and the low speed air amount adjusting portion 12b of the throttle valve 12 is substantially fully opened. ing. (The fully closed position of the low-speed air amount adjusting unit 12b is substantially the same position as the air inlet 12a shown by the solid line in FIG. 10 so as to close all the low-speed passages 1a to 4a in the junction 7)
[0040]
According to the second embodiment, the following effects can be obtained.
[0041]
Since both the throttle valve 12 and the switching valve 13 are constituted by cylindrical rotary valves, there is no need to switch between the fully open position and the fully closed position of the throttle valve 12 as in the first embodiment. The air quantity fluctuation | variation accompanying accompanying can be suppressed.
Further, since the throttle valve 12 and the switching 13 valve are integrated into a double rotary valve, the quality control of both valves 12 and 13 is facilitated.
[0042]
Since the throttle valve 12 is gradually opened from the upper side to the lower side of the junction 7, the low-speed passage 1a is used even when the throttle valve 12 is small when the low-speed passages 1a to 4a are used. The upper flow of ~ 4a is always allowed. Therefore, the upper flow in each of the low speed passages 1a to 4a, the merging portion 7, the common intake passage 8 and the intake port, which is the main flow of the air flow, is always allowed, and the vertical vortex is maintained regardless of the throttle valve opening. Generation can be facilitated.
[0043]
In the embodiment of the present invention, an example of a four-cylinder engine has been described. Further, although the example in which the common intake passage 8 is formed separately from the intake manifold M is shown, it may be formed integrally.
[Brief description of the drawings]
FIG. 1 is a front view of an intake manifold M as viewed from the front.
FIG. 2 is a perspective view of an intake air collecting portion and a surge tank.
3 is a plan view of the intake manifold M as viewed from the upper side of FIG. 1. FIG.
4 is a cross-sectional view taken along line IV-IV in FIG.
5 is a side view of the intake manifold M as viewed from one side of FIG.
FIG. 6 is a cross-sectional view of an intake manifold M according to the first embodiment.
FIG. 7 is a control block diagram.
FIG. 8 is a control flowchart of a throttle valve.
FIG. 9 is a control flowchart of the switching valve.
10 is a cross-sectional view of an intake manifold M according to a second embodiment, corresponding to FIG.
[Explanation of symbols]
1a to 4a: Low-speed passages 1b to 4b: High-speed passage 5: Intake collecting portion 7: Merging portion 8: Common intake passage 9: Intake port 12: Throttle valve 13: Switching valve

Claims (8)

An independent intake passage having a low speed passage with a long passage length and a high speed passage with a short passage length is provided for each cylinder, and each upstream end of the low speed passage and the high speed passage of each independent intake passage is an intake air collecting portion. And the downstream ends of the low-speed passages and the high-speed passages of the independent intake passages are joined to each other through a common intake passage that serves as both the low-speed passage and the high-speed passage after being joined at the junction. Intake of a multi-cylinder engine connected to the intake port of the multi-cylinder engine provided with a switching valve that switches the communication state of the low-speed passage and the high-speed passage to the common intake passage according to the operating state. In the apparatus, the switching valve is formed in a substantially L-shape, and a plate that operates independently of the switching valve within a substantially L-shaped range of the switching valve coaxially with the valve shaft of the switching valve. Equipped with a throttle valve It was,
An intake device for a multi-cylinder engine. The merging portions are sequentially arranged in the cylinder arrangement direction so that the merging portions overlap each other when viewed from one end side in the cylinder arrangement direction, and the valve shaft of the switching valve extends in the cylinder arrangement direction on the passage wall in each merging portion. Established,
The intake device for a multi-cylinder engine according to claim 1. The low speed passage extends from the engine lower side to the upper side and then merges with the merging portion, and the high speed passage extends from the engine upper side to the lower side and then merges with the merging portion. The intake passage is curved from the merging portion to the engine lower side and connected to the intake port of each cylinder to generate a vertical vortex in the air flowing into the combustion chamber,
The throttle valve is positioned so as to substantially extend along an upper passage wall extension line of the low speed passage when the throttle valve is substantially fully opened in a state where the high speed passage is closed and the low speed passage is opened. The tip is bent downward,
The intake device for a multi-cylinder engine according to claim 1. In the throttle valve, the relationship between the fully closed position and the fully opened position of the throttle valve is switched in accordance with switching of the communication state of the low speed passage and the high speed passage with respect to the common intake passage of the switching valve, and the throttle valve is operated. Throttle valve control means for switching the direction was provided,
The intake device for a multi-cylinder engine according to claim 1. An independent intake passage having a low speed passage with a long passage length and a high speed passage with a short passage length is provided for each cylinder, and each upstream end of the low speed passage and the high speed passage of each independent intake passage is an intake air collecting portion. And the downstream ends of the low-speed passages and the high-speed passages of the independent intake passages are joined to each other through a common intake passage that serves as both the low-speed passage and the high-speed passage after being joined at the junction. Intake of a multi-cylinder engine connected to the intake port of the multi-cylinder engine provided with a switching valve that switches the communication state of the low-speed passage and the high-speed passage to the common intake passage according to the operating state. In the apparatus, the switching valve is composed of a cylindrical rotary valve, and a slot composed of a cylindrical rotary valve that operates independently of the switching valve on the same axis as the valve shaft of the switching valve. Torr valve is provided,
An intake device for a multi-cylinder engine. The low speed passage extends from the engine lower side to the upper side and then merges with the merging portion, and the high speed passage extends from the engine upper side to the lower side and then merges with the merging portion. The intake passage is curved from the merging portion to the engine lower side and connected to the intake port of each cylinder to generate a vertical vortex in the air flowing into the combustion chamber,
The opening direction of the throttle valve is set to gradually open from the upper side of the common intake passage toward the lower side,
The multi-cylinder engine intake device according to claim 5. An independent intake passage having a low speed passage with a long passage length and a high speed passage with a short passage length is provided for each cylinder, and each upstream end of the low speed passage and the high speed passage of each independent intake passage is an intake air collecting portion. And the downstream ends of the low-speed passages and the high-speed passages of the independent intake passages are joined to each other through a common intake passage that serves as both the low-speed passage and the high-speed passage after being joined at the junction. Intake of a multi-cylinder engine connected to the intake port of the multi-cylinder engine provided with a switching valve that switches the communication state of the low-speed passage and the high-speed passage to the common intake passage according to the operating state. In the apparatus, a throttle valve that operates independently of the switching valve is provided on the same axis as the valve shaft of the switching valve.
An intake device for a multi-cylinder engine. The low speed passage is bundled at the intake collecting portion so that the low speed passage lengths from the intake collecting portion to the merging portion are substantially the same.
An intake device for a multi-cylinder engine according to any one of claims 1 to 7.

Images