JPH06159072A - Variable intake system for internal combustion engine - Google Patents

Abstract

PURPOSE:To enhance volume efficiency by means of initial supercharging effect in a wide range of operations in a limited volume of an air cleaner. CONSTITUTION:When air passes through a second upstream side intake pipe 24, comes out of a volume section 46, and goes into a downstream side intake pipe 28, if the downstream side control valves 62 and 66 of other volume sections 44 and 48 are closed, air goes in the downstream side intake pipe 28 as it goes, but if the downstream side control valves 62 and 66 of the other volume sections 44 and 48 are opened, it goes into the other volume sections 44 and 48 which are opened to the different direction from the flow direction of air. Therefore, the volume of intake air in the midway of an intake passage from an internal combustion engine 32 over to a releasing end to atmosphere can be made variable only by the volume of air which has come in the other volume sections 44 and 48 or by the volume which has not come in the aforesaid other volume sections depending on the open/close conditions of the downstream side control valves 62 and 66 of the other volume sections 44 and 48. And the downstream side control valves 62, 64 and 66 together with the upstream side control valves 68, 70 and 72 are controlled to be opened/closed depending on the revolution of the internal combustion engine.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable intake system for an internal combustion engine equipped with an air cleaner connected to the internal combustion engine.

[0002]

2. Description of the Related Art A variable intake system for an internal combustion engine is intended to obtain high volumetric efficiency over the entire operating condition such as the rotational speed of the internal combustion engine.

In the conventional variable intake system, as shown in FIG. 8, an air cleaner 104 containing a filter medium 105 is interposed in the middle of an intake pipe 102 connected to the internal combustion engine 100, and the air cleaner 104 and the internal combustion engine 100 are connected to each other. Between the bypass pipe 1 and the upstream side of the throttle valve 106.
08 is connected to the air cleaner 104 from the intake pipe 102, and a control valve 110 for opening and closing the intake pipe 102 is provided at the connection port.

The control valve 110 is controlled in conjunction with the rotation speed of the internal combustion engine 100, and the length of the intake passage from the air cleaner 104 to the internal combustion engine 100 is variable.

[0005]

By the way, in the above-mentioned conventional variable intake system, the distance L11 (distance from the internal combustion engine 100 to the surge tank 120) + distance L12 (distance from the surge tank 120 to the atmosphere open end of the intake pipe). ),
With respect to the natural frequency generated corresponding to the intake passage length of the distance L12, when the internal space of the air cleaner is large, the intake inertia supercharging effect is exhibited well when the natural frequency is low. Limited, it is not possible to expect improvement in volume efficiency due to intake inertia supercharging effect in a wide operating range.

Therefore, it is an object of the present invention to provide a variable intake system for an internal combustion engine which improves the volumetric efficiency due to the effect of inertial supercharging in a wide operating range within a limited volume.

[0007]

In order to solve the above-mentioned problems, the invention according to claim 1 is to provide a plurality of volume parts partitioned and formed, a filter medium housed in each volume part, and each volume part. An air cleaner having a control valve which is provided at least on the downstream side of the upstream side and the downstream side of the filter medium in at least one volume part of the filter medium and which is controlled to open and close in accordance with the rotational speed of the internal combustion engine; and a downstream side of the air cleaner. Is provided in
An upstream end is connected to each of the volumes in common, a downstream end is connected to a downstream intake pipe that is connected to an internal combustion engine via a throttle valve, and a downstream end is connected to the upstream side of the air cleaner. A variable intake system for an internal combustion engine, comprising: one or a plurality of upstream intake pipes that communicate with the volume portion and have an upstream end open to the atmosphere.

[0008]

In the present invention, in each of the respective volume parts, in addition to the control valve on the downstream side of the filter medium (that is, the downstream side control valve), a control valve (that is, the upstream side control valve) is also provided on the upstream side of the filter medium. According to this configuration, the air flows from the atmosphere into the volume portion where the upstream control valve is opened via the upstream intake pipe.

If the downstream control valve of the volume containing the air is also opened, the air passes through the volume loaded with the filter medium, is cleaned by the filter medium, and is directed toward the downstream intake pipe. Pour in. When the air passes through the downstream intake pipe, it is supplied to the combustion chamber of the internal combustion engine through the throttle valve and the surge tank.

When this air passes through the volume where both the upstream and downstream control valves are opened and goes to the downstream intake pipe, the downstream control valve for the other volume where air does not pass is If it is closed, the air will flow into the downstream intake pipe as it is. However, if the downstream control valve of the other volume where air does not pass is opened and at the same time the corresponding upstream control valve is closed, the air flow branches in a direction different from the air flow direction. Then, the air also enters the other volume through the opened downstream control valve.

Therefore, depending on the open / close state of the upstream side and downstream side control valves of the other volume section through which air does not pass, the air enters or does not enter the other volume section and the intake air from the internal combustion engine to the atmosphere open end is reached. The passage volume (stroke volume) is variable.

That is, if the upstream and downstream control valves are controlled to be opened / closed so that the intake passage volume (stroke volume) from the internal combustion engine to the atmosphere open end becomes appropriate according to the rotational speed of the internal combustion engine, a wider rotation is achieved. It is possible to improve the volumetric efficiency due to the effect of inertial supercharging over the range.

Here, an upstream intake pipe having different pipe lengths and diameters and a volume portion having various volumes capable of obtaining proper intake passage length and intake passage cross-sectional area from the internal combustion engine to the atmosphere open end. By appropriately communicating with and, it is possible to improve the volumetric efficiency due to the inertial supercharging effect in a wider operating range in combination with the inertial supercharging effect due to the volume change of the volume section.

Further, in the present invention, in each of the respective volume parts, although there is a downstream side control valve but no upstream side control valve, air originates from the atmosphere and passes through the upstream side intake pipe. Flow into all volumes. here,
In the volume portion in which the downstream control valve is opened, the air passes through the volume portion, at which time the air is cleaned by the filter medium and flows toward the downstream intake pipe. Then, it is supplied to the combustion chamber of the internal combustion engine through the throttle valve and the surge tank. In the volume portion in which the downstream control valve is closed, the air is blocked by the downstream control valve, and there is no air flow. Here, the intake passage volume (stroke volume) and the intake passage cross-sectional area change depending on which downstream control valve is opened and how many downstream control valves are opened. Since it is possible to change the rotational speed range of the internal combustion engine, by controlling the opening / closing of the downstream side control valve, it is possible to improve the volumetric efficiency due to the inertia supercharging effect over a wide rotational range.

Further, according to the present invention, in the structure provided with the volume part without the downstream side control valve, the air can always pass through the volume part, but the downstream side control valve and the upstream side are provided to other volume parts. When both control valves are provided, the intake passage volume (stroke volume) can be changed by opening / closing the downstream control valve and the upstream control valve of the other volume portion, or If there is only the downstream side control valve, the intake passage volume (stroke volume) and the intake passage cross-sectional area can be changed by controlling the opening and closing of the downstream side control valves of the other volume parts, and similarly, a wide rotation Throughout the range, the volumetric efficiency is improved due to the inertia supercharging effect.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a variable intake system for an internal combustion engine according to the present invention will be described in detail with reference to FIGS.

As shown in FIG. 1, the housing 12 of the air cleaner 10 is provided with an outlet 14 projecting at the center of one end (left end in FIG. 1) and at the other end (see FIG. 1).
At the right end), three inlet joints 16, 18, 20
Are formed side by side in a protruding manner. A downstream side intake pipe 28 is fitted and connected to the outer peripheral surface of the outlet 14, and three upstream side intake pipes 22, 24 and 26 are fitted and connected to the outer peripheral surface of each inlet 16, 18, 20. There is.

The upstream intake pipes 22, 24, 26 are formed so that their pipe lengths and diameters (pipe cross-sectional areas) are different from each other, and the first, second, and third upstream sides are arranged in order from the top in FIG. The intake pipes 22, 24 and 26 are used. That is, the first upstream intake pipe 22 has a length of a distance L1 from this reference position, with one end on the downstream side of the continuous rear chamber 58, which will be described later, as a reference position, and the second upstream intake pipe 24 has a reference length. The third upstream side intake pipe 26 has a length L2 from the position, the third upstream side intake pipe 26 has a length L3 from the reference position, and the first upstream side intake pipe 22 has a diameter of three upstream sides. It is the largest of the intake pipes, and the diameter of the second upstream intake pipe 24 is the smallest of the three upstream intake pipes.

The downstream side intake pipe 28 is single, and the end of the downstream side intake pipe 28 opposite to the air cleaner 10 is connected to the surge tank 30, and the surge tank 30 is connected to each cylinder of the internal combustion engine 32. It is connected to the internal combustion engine 32 via an intake manifold 34 that is formed in a branched manner corresponding to each cylinder.

A throttle valve 36 is housed inside the downstream intake pipe 28 at a connection position with the surge tank 30 (a position separated from the reference position by a distance L4).

A filter body 38 is provided in the housing 12 of the air cleaner 10. The filter body 38 includes the outer frame 40 and the two rib plates 42, and the three chamber volume parts 44,
46, 48 (from the top in FIG. 1, the first volume 44, the second
These are defined as a volume 46 and a third volume 48). Each rib plate 42 is arranged parallel to the air flow direction (arrow A in FIG. 1), and a filter medium 50 is housed in the center of each volume 44, 46, 48 in the air flow direction. In addition, when viewed from the air flow direction, the housing 12
Has a rectangular cross section and each volume 44, 46, 48
Each of the cross sections has a rectangular shape, and its area is the volume 4
4, the volume section 46, and the volume section 48 are increased in this order (FIG. 2).

A filter medium 50 is provided in each of the volumes 44, 46 and 48.
Front chambers 52 are formed on the upstream side of the inlet joint 1 through the front chambers 52.
6, 18 and 20 communicate with each other.

Further, in the volumes 44, 46, 48, rear chambers 54 are formed on the downstream sides thereof, respectively, and further, downstream of the respective rear chambers 54, on the downstream side thereof, on the extension line of the rib plate 42, the housing is formed. Subsequent rear chambers 58 are respectively formed by the partition walls 56 formed in 12.

Further, a common rear chamber 60 is formed on the downstream side of the continuous rear chamber 58 so as to be able to communicate with the respective volume portions 44, 46, 48, and the common rear chamber 60 is communicated with the inside of the outlet joint 14.

Then, in each of the volumes 44, 46, 48,
In the rear chamber 58, downstream control valves 62, 64, 66 for opening and closing the intake passage (first downstream control corresponding to the first volume section 44, the second volume section 46, and the third volume section 48, respectively). Valve 62, second downstream side control valve 64, and third downstream side control valve 66), respectively, and also opens and closes the intake passage between each front chamber 52 and the inlet joint 16, 18, 20. Upstream control valve 6 for
8, 70, 72 (first upstream control valve 68, second upstream control valve 70, third upstream control valve corresponding to the first volume 44, the second volume 46, and the third volume 48, respectively) 72) are provided respectively.

These downstream control valves 62, 64, 6
6. The upstream control valves 68, 70, 72 are controlled to be opened / closed via the control unit 76 while gradually changing the opening degree according to the rotation speed of the internal combustion engine 32. For example, the rotation speed of the internal combustion engine 32 is detected by detecting the rotation of the single rotor 78 attached to a camshaft (not shown) by the pickup 82, and the opening / closing control is performed based on the detected rotation speed.

Incidentally, reference numeral 74 in FIG. 1 denotes a housing recess for housing the filter body 38. Next, the operation of this embodiment will be described.

The air is supplied from outside air to the upstream control valves 68, 70, 72 and the downstream control valves 62, 64, 66 of the upstream intake pipes 22, 24, 26 having different pipe lengths and diameters. Volume 4 where both are opened
4, 46, 48 and the upstream side intake pipes 22, 24, 2
One or two of the upstream intake pipes 6 or all upstream intake pipes 6 enter into the front chamber 52 of the volume communicating with the upstream intake pipe. Then, the air passes through the filter medium 50 to be cleaned, passes through the rear chamber 54, and then the rear chamber 58, and passes through the volume 4
The common rear chamber 60 exits from any one of the volumes 4, 46, and 48, or the combined volume thereof. Further, the air passes through the downstream intake pipe 28, the throttle valve 36, and
It enters the surge tank 30 and is further supplied to each cylinder of the internal combustion engine 32 via the intake manifold 34.
In FIG. 1, only the second upstream side control valve 70 and the second downstream side control valve 64 are opened.

The air passes through only the volume portions of the volume portions 44, 46, 48 where both the upstream side control valves 68, 70, 72 and the downstream side control valves 62, 64, 66 are opened, and the downstream side intake pipe 28, the upstream control valves 68, 70, 72 or the downstream control valves 62, 6
When at least one of the control valves 4 and 66 is closed and the downstream side control valves of the other volumes where air does not pass are all closed, the air flows to the upstream side control valve 68. , 70, 72 and the downstream control valve 6
After 2, 64 and 66 have passed through the opened volume, they enter the downstream intake pipe 28 as they are.

However, at least one of the downstream side control valves of the other volume portions where air does not pass (either one of the first downstream side control valve 62 and the third downstream side control valve 66 in FIG. 1). Control valve or both control valves are opened, and any one of the upstream control valve 68 (the first upstream control valve 68 and the third upstream valve 72 in FIG. 1) corresponding to the control valve is opened. When the control valve or both control valves are closed, the air enters the other volume that opens in the direction orthogonal to the air flow direction, and the volume of this volume (volume) itself. Acts as a part of the volume (stroke volume) in the middle of the intake passage.

Therefore, depending on the open / closed state of the downstream side control valve corresponding to the volume section through which air does not pass, the volume sections 44, 4 are
It is determined which of the volume sections 6, 48 the air enters or does not enter, that is, which of the volume sections 44, 46, 48 acts as a volume in the middle of the intake passage due to the air not passing or does not work. Therefore, the volume (stroke volume) in the middle of the intake passage from the internal combustion engine 32 to the atmosphere open end can be made variable by opening / closing the control valve.

Here, according to the rotation speed of the internal combustion engine 32,
The downstream side control valves 62, 6 are provided so as to secure a predetermined volume in the middle of the intake passage from the internal combustion engine 32 to the atmosphere open end.
If the opening and closing control of the internal combustion engines 32 and 66 is performed, for example, as the rotational speed (or rotational speed) of the internal combustion engine increases, the opening and closing control is performed so as to decrease the volume of the internal combustion engine 32. The volume efficiency can be improved by the supercharging effect.

As a result, the volumetric efficiency can be improved by the effect of inertia supercharging in a wide operating range within the limited space of the air cleaner.

On the other hand, the upstream intake pipes 22, 24 and 26 are
Since the pipe length is different and the bore is different, the internal combustion engine 3
2, the upstream intake pipes 22, 24, 26 having an appropriate intake passage length and passage cross-sectional area between the internal combustion engine 32 and the atmosphere open end are selected, and the selected upstream side is selected. Volumes 44, 4 communicating with the intake pipes 22, 24, 26
If the downstream control valves 62, 64, 66 and the upstream control valves 68, 70, 72 of 6, 48 are opened,
For example, as the rotational speed (or rotational speed) of the internal combustion engine increases, by selecting the upstream intake pipe having a short intake pipe length and the volume portion having a small volume, the operating condition of the internal combustion engine 32 is reduced over the entire operating condition. The volumetric efficiency can be improved by the effect of inertia supercharging over a wide operating region in the internal space of the air cleaner.

In other words, by varying the volume of the intake passage from the internal combustion engine 32 to the open end of the atmosphere, the upstream intake pipe 2 having a predetermined intake passage length and passage cross-sectional area.
By combining the selection of 2, 24, and 26, respectively, it is possible to perform more appropriate and fine control for the improvement of the volumetric efficiency due to the inertia supercharging effect.

As in the modification shown in FIG. 9, one of the volumes 80, 46, 48 (first volume in FIG. 9).
The volume 80) has neither a downstream control valve nor an upstream control valve, and air can always pass through the first volume 80.

According to this structure, in the first volume section 80, the passage of air cannot be blocked, and the range in which the volume of the intake passage can be varied is limited to this extent, but the other volume sections 46 and 48 are limited. Downstream control valves 64, 6 in
The intake passage volume can be varied by controlling the opening and closing of the upstream control valves 70 and 72, and the downstream control valve 62 and the upstream control valve 68 in the first volume portion of the first embodiment both open and open. The state is equivalent to the state in which the state is maintained, and as long as the state is maintained, the same operational effect as that of the first embodiment can be obtained.

In view of the above, among the plurality of volume parts, both the downstream side control valve and the upstream side control valve are not provided, and the air is always passed through so that the internal combustion engine 32 side and the atmosphere side are communicated with each other. There may be a part, and this is the same for each of the embodiments described below.

Next, a second embodiment will be described with reference to FIG. In this embodiment, the housing 1 of the air cleaner 151
50 has a common rear chamber 60 on the downstream side.
In addition to 0, further downstream, three branched connection ends having different diameters (here, 132 is the first connection end, 134 is the second connection end, and 136 is the third connection end) are formed. There is.

On the downstream side of these connecting ends, the three branch parts 156, 158, 160 on the upstream side (the first connecting end 132,
156 corresponds to the first branch portion, 158 corresponds to the second branch portion, and 160 corresponds to the second connection end 134 and the third connection end 136, respectively.
Is a third branch portion), and the branch portions 156, 158, 160 are connected to the corresponding connecting ends 132, 13 via the three connecting pipes 152, respectively.
4, 136. On the downstream side of the branch pipe 154, the three branch portions 156, 158, 160 are gathered at the common portion 166, and the common portion 166 communicates with the outlet joint 14.

Then, the respective branch parts 156, 158, 160.
The downstream end of the control valve 168, 170, 172 for opening and closing the intake passage (the first branch portion 156, the second branch portion 158, and the third branch portion 160 respectively corresponding to the first downstream portion). Downstream control valve 168, second most downstream control valve 170, and third most downstream control valve 172) are respectively provided.

Further, the first branch portion 156 and the second branch portion 15
8, the third branch part 160 has a different cross-sectional area, and the intake passage length when the air passes through the first branch part 156, the intake passage length when the air passes through the second branch part 158, Since the intake passage lengths when passing through the third branch portion 160 are different from each other, depending on the open / close state of the most downstream control valves 168, 170, 172, the volume portions 44, 46, 48 to the throttle valve 36. It is possible to change the intake passage length and the intake passage cross-sectional area between.

Therefore, the downstream control valves 62, 64, 6
6 synergistically with the variable effect according to the engine speed of a part of the system upstream of 6 and the variable effect according to the engine speed brought by the branch pipe 154 and the most downstream control valves 168, 170, 172. Therefore, the intake inertia effect is exerted over a wider range of rotational speeds, and the improvement in volume efficiency can be favorably maintained.

Next, a third embodiment will be described with reference to FIG. In this embodiment, there is one upstream intake pipe 180. Further, in the housing 204 of the air cleaner 202, the volumes 182, 184, 186 are provided upstream of the front chambers 52 on the extension line of the front chambers 52 by the partition wall 188 formed in the housing 204. Are formed. A common front chamber 1 that is in common communication with the respective volume parts 182, 184, 186 is further upstream of the front front chamber 190.
92 is formed so that the common front chamber 192 communicates with the inside of the inlet joint 194. The upstream control valves 196, 198, 200 are provided in the front chamber 190.

According to this, the air is generated by using the outside air as a source.
Downstream control valves 62, 6 via the upstream intake pipe 180
4, 66 and the upstream side control valves 196, 198, 200 are all opened (182, 184, 1).
Any or all of 86). Then, the air passes through the downstream intake pipe 28 and is supplied to each cylinder of the internal combustion engine 32. Note that, in FIG. 4, the second upstream control valve 198 and the second downstream control valve 64 are opened.

Further, the air is transferred to the volumes 182, 184, 1
Of each volume 182, 184, 186
Corresponding to the upstream side control valves 196, 198, 200 and the downstream side control valves 62, 64, 66 are both opened, the volume sections 182, 184, 186 (in FIG. 4, the volume section 184 is shown).
(Corresponding to) and toward the downstream intake pipe 28,
If at least one of the control valves is closed and all the downstream side control valves corresponding to other volume portions through which air does not pass are closed, the air flows into the downstream side intake pipe 28 as it is.

However, the downstream side control valve (the first downstream side control valve 6 in FIG. 4) of the other volume portion (corresponding to the volume portions 182 and 186 in FIG. 4) through which air has not passed.
2, which corresponds to the third downstream control valve 66, and any one of the first downstream control valve 62 and the third downstream control valve 66, or both control valves) is opened. At least one of the other volume portions that does not pass is opened in the direction orthogonal to the air flow direction, and the volume of the other volume portions acts as a volume (stroke volume) in the middle of the intake passage.

That is, similar to the first embodiment, the other volume portions are set as the volume (stroke volume) in the middle of the intake passage according to the open / close state of the downstream side control valve corresponding to the other volume portions through which air does not pass. The degree of action changes (including the case where it does not act as the stroke volume). In other words, the stroke volume from the internal combustion engine to the atmosphere open end can be made variable by controlling the opening / closing of the control valve.

According to this, the same operational effect as that of the first embodiment can be obtained except that the upstream intake pipe cannot be selected.

The other structure is the same as that of the first embodiment. Next, a fourth embodiment will be described with reference to FIG.

The air cleaner 258 of this embodiment has no upstream side control valve in the housing 260.
It is similar to the first embodiment except that only the downstream control valves 62, 64, 66 are provided.

According to this structure, the air uses the outside air as a source, and the volume parts 250, 252, 254 (corresponding to the volume part 252 in FIG. 5) in which the downstream side control valves 62, 64, 66 are opened. Only its volume 250, 25
2, 254 and the corresponding upstream intake pipes 22, 24, 26
(In FIG. 5, it is inhaled through the upstream intake pipe 24). The air sucked into the volumes 250, 252, 254 is cleaned by passing through the filter medium 50 provided in the volumes 250, 252, 254, and exits the volumes 250, 252, 254. After that, the air passes through the downstream intake pipe 28 and the surge tank 30, and passes through the internal combustion engine 3
2 is supplied.

Therefore, by controlling the opening / closing of the downstream side control valves 62, 64, 66 in accordance with the operating conditions (rotational speed) of the internal combustion engine 32, the volume 25 as an intake passage is formed.
0, 252, 254 is selected, and a plurality of downstream side control valves 62, 64,
By opening 66, an intake passage can be formed by arbitrarily combining the intake passages.

That is, since the intake passage length, the intake passage cross-sectional area, and the stroke volume (stroke volume) can be changed by opening and closing the downstream control valve, the inertia over a wide range of engine speeds of the internal combustion engine 32. The volume efficiency can be improved by the supercharging effect. Further, similarly to the first embodiment, if pipes having different lengths and diameters are used as the upstream intake pipes 22, 24, 26, the volume parts 250, 25 will be obtained.
In combination with the effect of the volume change of 2,254, a wider range of inertia supercharging effect is achieved.

Next, a fifth embodiment will be described with reference to FIG. In this embodiment, the casing 2 of the air cleaner 280
82 is divided into a downstream side and an upstream side along the air length direction, and the outer frame 40 of the filter body 38 is sandwiched and attached between the respective divided members. A part of the outer frame 40 of the filter body 38 is exposed.

Next, a sixth embodiment will be described with reference to FIG. In this embodiment, the upstream side control valves 300, 301 of the three upstream side control valves are cantilever type instead of butterfly type, and the volume sections 292, 293, 29.
4 has the same configuration as that of the first embodiment except that communication holes 295 and 296 for communicating adjacent volume portions are formed on the upstream side of the partition wall 42.

Cantilever type upstream control valves 300, 30
1 can control the upstream intake pipes 22 and 26 respectively corresponding to the communication state or the closed state by the opening / closing operation, and at the same time, the communication holes 295 and 296 can also be opened / closed.

In this embodiment as well, the opening and closing of the control valve is controlled according to the number of revolutions of the internal combustion engine as in the above embodiments, and the intake passage length, the intake passage cross-sectional area, and the stroke volume are adjusted depending on the degree of opening and closing. Can be changed to obtain the inertia supercharging effect over a wide operating range.

Although the present invention has been described with reference to the respective embodiments and modifications, the present invention is not limited to the above embodiments and modifications, and various modifications can be made.

For example, the number of upstream intake pipes, capacity parts, control valves, filter media, etc. is not limited to the above-mentioned embodiments and modifications.

[0061]

As described above, in the variable intake system for an internal combustion engine according to the present invention, the volumetric efficiency can be improved by the inertia supercharging effect over a wide operating range even in the limited volume in the air cleaner.

[Brief description of drawings]

FIG. 1 is a sectional view of a variable intake system according to a first embodiment of the present invention, taken along the air flow direction.

FIG. 2 is a cross-sectional view of the variable intake system according to the first embodiment as seen from the air flow direction.

FIG. 3 is a cross-sectional view of the variable intake system according to the second embodiment of the present invention taken along the air flow direction.

FIG. 4 is a cross-sectional view of the variable intake system according to the third embodiment of the present invention taken along the air flow direction.

FIG. 5 is a sectional view of a variable intake system according to a fourth embodiment of the present invention, taken along the air flow direction.

FIG. 6 is a sectional view of a variable intake system according to a fifth embodiment of the present invention, taken along the air flow direction.

FIG. 7 is a sectional view of a variable intake system according to a sixth embodiment of the present invention, taken along the air flow direction.

FIG. 8 is a schematic diagram of a conventional variable intake system.

FIG. 9 is a cross-sectional view of a modification of the variable intake system according to the first embodiment, taken along the air flow direction.

[Explanation of symbols]

 10 Air Cleaner 22, 24, 26 Upstream Intake Pipe 28 Downstream Intake Pipe 32 Internal Combustion Engine 36 Throttle Valve 44, 46, 48 Volume 50 Filter Media 62, 64, 66 Downstream Control Valve 68, 70, 72 Upstream Control Valve

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Keinobu Nagasaka 1-1, Toyota-cho, Kariya City, Aichi Prefecture Toyota Boshoku Co., Ltd.

Claims (1)

[Claims] 1. A plurality of volume parts partitioned and formed, a filter medium contained in each volume part, and at least one of the upstream side and the downstream side of the filter medium in at least one of the volume parts. An air cleaner having a control valve provided on the downstream side and controlled to open and close in accordance with the number of revolutions of the internal combustion engine, and provided on the downstream side of the air cleaner, and an upstream end is commonly communicated with each of the volume parts, and a downstream side. A downstream intake pipe whose side end communicates with the internal combustion engine via a throttle valve, a downstream end connected to the upstream side of the air cleaner and communicated with the volume, and an upstream end open to the atmosphere. A variable intake system for an internal combustion engine, comprising: one or a plurality of upstream intake pipes;