JP2005337177A - Intake device for multi-cylinder internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve intake noise quality and improve performance by controlling flow of intake air according to an operation condition of an engine in an intake device for a multi-cylinder internal combustion engine. <P>SOLUTION: Intake air passages 41a-41d, 42a-42d of intake manifolds 22a, 22b are communicated to a surge tank 23 by first communication ports 43a-43d, 45a-45d having long distances to intake ports 18a, 18b and second communication ports 44a-44d, 46a-46d having short distances. A downstream side end part of an intake pipe 24 is positioned at a roughly center part in the surge tank 23. Deflection nozzle 50 is rotatably installed. Direction of the deflection nozzle 50 is changed according to engine operation condition to selectively guide intake air to the first communication ports 43a-43d, 45a-45d or the second communication port 44a-44d, 46a-46d. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an intake device for a multi-cylinder internal combustion engine for efficiently introducing air from an intake pipe to each combustion chamber of the internal combustion engine via a surge tank.

  In a general multi-cylinder internal combustion engine, a plurality of cylinder bores are formed in series in an engine body, pistons are fitted to the cylinder bores so as to be vertically movable, and intake ports and exhaust ports are provided in the combustion chambers. In addition, an injector for injecting fuel into the intake port or the combustion chamber is mounted, and an ignition plug is mounted in the combustion chamber. The intake pipe is provided with an air cleaner at the upstream end, and the downstream end is connected to an intake port via a surge tank and an intake manifold. On the other hand, the upstream end of the exhaust pipe is connected to the exhaust port, and a catalyst and a silencer are mounted on the downstream side.

  In such a multi-cylinder internal combustion engine, air is sucked into the intake pipe from the air cleaner, flows into the surge tank and is stored therein, flows from each intake passage of the intake manifold to each intake port, and burns when the intake valve is opened Introduced into the room. In this case, in the surge tank, since there are a plurality of intake passage inlets with respect to the outlet of one intake pipe, the distance from the outlet to the inlet of each intake passage is different. There is a problem in that the pressure distribution is biased and the performance of the internal combustion engine is degraded, or the intake sound quality is deteriorated due to vibration.

  As an intake device for an internal combustion engine that solves such a problem, for example, there is a technique described in Patent Document 1 below. The intake device for a V-type engine described in Patent Document 1 is extended by providing a collector communicating with an intake pipe in a surge tank, and by providing a plurality of air holes on the side of the collector. The high torque is obtained from the low rotation range to the high rotation range.

Japanese Patent Laid-Open No. 7-102978

  However, in the intake device disclosed in Patent Document 1, although the tip of the collector communicating with the intake pipe is located in the middle of the surge tank, the intake air that has flowed into the surge tank enters each passage of the intake manifold. It does not flow efficiently, and the distribution of intake flow velocity and pressure is biased among the cylinders. In the case where a plurality of air holes are provided on the side surface of the collector, the length of the intake system is the same regardless of the operating state of the engine, and the resonance supercharging effect cannot be sufficiently obtained.

  The present invention is intended to solve such problems, and is a multi-cylinder internal combustion engine that improves the performance by improving the intake sound quality and controlling the flow of intake air in accordance with the operating state of the engine. An object is to provide an air intake device.

  In order to solve the above-described problems and achieve the object, an intake device for a multi-cylinder internal combustion engine of the present invention has a downstream end portion of an intake pipe connected to a surge tank, and the surge tank is connected to a plurality of intake passages. In the intake device for an internal combustion engine connected to each intake port of the internal combustion engine, each intake passage communicates with the surge tank through a first communication port and a second communication port that have different distances to the respective intake ports. The intake pipe has a downstream end located substantially in the middle of the surge tank in the juxtaposition direction of the first communication port or the second communication port, and from the downstream end of the intake pipe. Guide means for selectively guiding intake air introduced into the surge tank to the first communication port or the second communication port is provided.

  In the intake device for a multi-cylinder internal combustion engine according to the present invention, the guide means guides intake air to the first communication port having a long distance to the intake port when the internal combustion engine rotates at a low speed, while the internal combustion engine operates at a high speed. Sometimes, the intake air is guided to the second communication port having a short distance to the intake port.

  In the intake system for a multi-cylinder internal combustion engine according to the present invention, the guide means is a deflection nozzle rotatably attached to a downstream end portion of the intake pipe, and the deflection nozzle is arranged in accordance with the operating state of the internal combustion engine. It is characterized by changing the direction of intake and changing the direction of intake.

  In the intake system for a multi-cylinder internal combustion engine of the present invention, the guide means is a deflection plate that is rotatably mounted facing the downstream end portion of the intake pipe, and depends on the operating state of the internal combustion engine. The guide direction of the intake air is changed by changing the direction of the deflecting plate.

  According to the intake system for a multi-cylinder internal combustion engine of the present invention, each intake passage communicates with the surge tank through the first communication port and the second communication port having different distances to the respective intake ports, while the downstream end of the intake pipe Is located substantially in the middle in the direction in which the first communication port or the second communication port is juxtaposed in the surge tank, and intake air introduced into the surge tank from the downstream end of the intake pipe is supplied to the first communication port or the second communication port. Since the guide means for selectively guiding the two communication ports is provided, the downstream end portion of the intake pipe is positioned at the intermediate portion of the surge tank, so that the respective downstream end portions of the intake pipe in the surge tank The distance to the inlet of the intake passage is almost the same, it is possible to improve the intake sound quality by suppressing the occurrence of abnormal intake noise, and the intake air that flows into the surge tank from the intake pipe is guided to each communication port by the guide means The It is possible to improve performance by controlling the flow of intake air in accordance with the emission of the operating conditions.

  Embodiments of an intake device for a multi-cylinder internal combustion engine according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

  1 is a partially cutaway front view showing an intake device of a multi-cylinder internal combustion engine according to Embodiment 1 of the present invention, and FIG. 2 is a partially cutaway plan view showing an intake device of the multi-cylinder internal combustion engine of Embodiment 1. 3 is a cross-sectional view taken along the line III-III in FIG. 2, FIG. 4-1 is a schematic front view showing the intake device during low rotation of the internal combustion engine, and FIG. 4-2 shows the intake device during low rotation of the internal combustion engine. FIG. 5A is a schematic front view showing the intake device when the internal combustion engine is rotating at high speed, FIG. 5B is a schematic side view showing the intake device when the internal combustion engine is rotating at high speed, and FIG. 1 is a schematic view of a V-type 8-cylinder engine to which an intake device for a multi-cylinder internal combustion engine of Example 1 is applied.

  In the first embodiment, a V-type 8-cylinder engine is applied as a multi-cylinder internal combustion engine, and the V-type 8-cylinder engine is equipped with the intake device of the present invention. First, in this V-type 8-cylinder engine, as shown in FIG. 6, the cylinder block 11 has two banks 12a and 12b inclined at a predetermined angle on the upper portion, and each of the banks 12a and 12b has four cylinder bores. 13a and 13b are formed, and pistons 14a and 14b are fitted to the cylinder bores 13a and 13b so as to be movable up and down. A crankshaft (not shown) is rotatably supported at the lower part of the cylinder block 11, and the pistons 14a and 14b are connected to the crankshaft via connecting rods 15a and 15b, respectively.

  On the other hand, cylinder heads 16a and 16b are fastened to the upper portions of the banks 12a and 12b of the cylinder block 11, and the combustion chambers 17a and 17b are constituted by the cylinder block 11, the pistons 14a and 14b, and the cylinder heads 16a and 16b. ing. The intake ports 18a and 18b and the exhaust ports 19a and 19b are formed to face the upper portions of the combustion chambers 17a and 17b, that is, the lower surfaces of the cylinder heads 16a and 16b, and the intake ports 18a and 18b and the exhaust ports 19a and 19b are formed. The lower ends of the intake valves 20a and 20b and the exhaust valves 21a and 21b are located with respect to 19b. Accordingly, when the intake valves 20a and 20b and the exhaust valves 21a and 21b move up and down at a predetermined timing, the intake ports 18a and 18b and the exhaust ports 19a and 19b are opened and closed, and the intake ports 18a and 18b and the combustion chamber 17a, 17b, the combustion chambers 17a, 17b and the exhaust ports 19a, 19b can be communicated with each other.

  A surge tank 23 is connected to the intake ports 18a and 18b via intake manifolds 22a and 22b. An intake pipe 24 is connected to the surge tank 23, and an air cleaner is connected to an air intake port of the intake pipe 24. 25 is attached. The intake pipe 24 is provided with an electronic throttle device 26 having a throttle valve located on the downstream side of the air cleaner 25. Further, injectors 27a, 27b for injecting fuel (gasoline) into the combustion chambers 17a, 17b are mounted on the cylinder heads 16a, 16b, and spark plugs 28a, 27b are positioned above the combustion chambers 17a, 17b. 28b is attached.

  On the other hand, an exhaust pipe 30 is connected to the exhaust ports 19a and 19b via exhaust manifolds 29a and 29b. A catalyst device 31 is attached to the exhaust pipe 30.

  Further, an electronic control unit (ECU) 32 is mounted on the vehicle, and the ECU 32 can control the fuel injection timing of the injectors 27a and 27b, the ignition timing of the spark plugs 28a and 28b, and the like. The fuel injection amount, the injection timing, the ignition timing, and the like are determined based on the engine operating state such as the intake air amount, the throttle opening (accelerator opening), and the engine speed. That is, an air flow sensor 33 is mounted on the upstream side of the intake pipe 24 and outputs the measured intake air amount to the ECU 32. Further, the electronic throttle device 26 outputs the current throttle opening degree to the ECU 32, and the engine speed sensor 34 outputs the detected engine speed to the ECU 32.

  Next, the intake device of the present embodiment will be described in detail. In this intake device, as shown in FIGS. 1 to 3, the downstream end portion of the intake pipe 24 is connected to a surge tank 23, and the surge tank 23 includes eight intake passages 41a to 41d in the intake manifolds 22a and 22b. , 42a to 42d are connected to the intake ports 18a and 18b. The surge tank 23 has a sealed elliptic cylindrical shape, and one end is connected to the intake pipe 24 and the outer peripheral surface is connected to the intake passages 41a to 41d and 42a to 42d. That is, the intake passages 41 a to 41 d connected to the one intake port 18 a are curvedly extended from the upper outer peripheral surface to the lower outer peripheral surface of the surge tank 23 on the upstream side, and are formed in the lower portion of the surge tank 23. The surge tank 23 communicates with the surge tank 23 via the first communication ports 43a to 43d, and communicates with the surge tank 23 via the second communication ports 44a to 44d formed in the upper portion. In this case, the communication ports 43a to 43d and 44a to 44d have different distances to the intake port 18a, the distances from the first communication ports 43a to 43d to the intake port 18a are long, and the second communication ports 44a to 44a. The distance from 44d to the intake port 18a is set short.

  In addition, the intake passages 42a to 42d connected to the other intake port 18b are curved and extended from the upper outer peripheral surface of the surge tank 23 to the lower outer peripheral surface on the opposite side of the intake passages 41a to 41d, It communicates with the surge tank 23 via first communication ports 45a to 45d formed in the lower part of the surge tank 23, and communicates with the surge tank 23 via second communication ports 46a to 46d formed at the upper part. Yes. In this case, the communication ports 45a to 45d and 46a to 46d have different distances to the intake port 18b, the distances from the first communication ports 45a to 45d to the intake port 18b are long, and the second communication ports 46a to 46a The distance from 46d to the intake port 18b is set short.

  On-off valves 47a to 47d and 48a to 48d are mounted on the second communication ports 44a to 44d and 46a to 46d in the intake passages 41a to 41d and 42a to 42d, respectively. The on-off valves 47a to 47d and 48a to 48d are opened and closed in synchronism with one drive device 49, and the drive device 49 can be driven and controlled by the ECU 32 in accordance with the engine operating state. That is, the ECU 32 controls the drive device 49 to close the second communication ports 44a to 44d and 46a to 46d by the on-off valves 47a to 47d and 48a to 48d when the engine is rotating at a low speed, while opening and closing the valves when the engine is at a high speed. The second communication ports 44a to 44d and 46a to 46d are opened by 47a to 47d and 48a to 48d.

  On the other hand, the downstream end of the intake pipe 24 is located at a substantially intermediate portion in the juxtaposed direction of the first communication ports 43a to 43d, 45a to 45d or the second communication ports 44a to 44d and 46a to 46d in the surge tank 23. doing. The intake air introduced into the surge tank 23 is selectively guided to the first communication ports 43a to 43d, 45a to 45d or the second communication ports 44a to 44d and 46a to 46d at the downstream end of the intake pipe 24. A deflection nozzle 50 is installed as a guiding means.

  The deflection nozzle 50 has a base end portion rotatably fitted to a downstream end portion of the intake pipe 24, and an opening 51 having a shape that is obliquely curved and cut at the tip end portion. A ring gear 52 is fixed to the base end portion of the deflection nozzle 50, and a drive motor 53 is attached to the intake pipe 24, and the drive gear 54 of the drive motor 53 meshes with the ring gear 52 of the deflection nozzle 50. . The drive motor 53 can be driven and controlled by the ECU 32 in accordance with the engine operating state.

  That is, the ECU 32 controls the drive motor 53 and rotates the deflection nozzle 50 when the engine is rotating at low speed to direct the opening 51 toward the first communication ports 43a to 43d and 45a to 45d. While guiding to the first communication ports 43a to 43d and 45a to 45d, the deflection nozzle 50 is rotated and the opening 51 is directed to the second communication ports 44a to 44d and 46a to 46d when the engine rotates at high speed. Are guided to the second communication ports 44a to 44d and 46a to 46d.

  Here, the operation of the intake device of the multi-cylinder internal combustion engine of the first embodiment will be described. As shown in FIG. 6, air flows into the intake pipe 24 from the air cleaner 25 and is taken into the intake ports 18a and 18b via the surge tank 23 and the intake manifolds 22a and 22b, and the combustion chamber is opened and closed when the intake valves 20a and 20b are opened and closed. The fuel amount corresponding to the air amount is injected into the combustion chambers 17a and 17b from the injectors 27a and 27b. The air / fuel mixture is ignited and burned after being compressed by the spark plugs 28a and 28b, and the combustion gas is discharged from the exhaust ports 19a and 19b to the exhaust manifolds 29a and 29b as exhaust gas when the exhaust valves 21a and 21b are opened and closed. It is discharged and discharged to the outside through the exhaust pipe 30.

  When taking in the air described above, the ECU 32 performs opening / closing control of the opening / closing valves 47a to 47d and 48a to 48d based on the engine speed detected by the engine speed sensor 34, and controls the direction of the deflection nozzle 50.

  That is, as shown in FIGS. 4A and 4B, when the engine is running at a low speed, the ECU 32 controls the driving device 49 to control the second communication ports 44 a to 44 d, by the on-off valves 47 a to 47 d and 48 a to 48 d. While 46a-46d is closed, the drive motor 53 is drive-controlled and the deflection | deviation nozzle 50 is rotated, and the opening part 51 is orient | assigned to the 1st communicating port 43a-43d, 45a-45d side. Therefore, the air introduced into the surge tank 23 from the intake pipe 24 enters the intake passages 41a to 41d and 42a to 42d from the first communication ports 43a to 43d and 45a to 45d, and passes through the intake ports 18a and 18b. Then, it is sucked into the combustion chambers 17a and 17b. Therefore, when the engine is running at a low speed, the intake path length from the surge tank 23 through the intake manifolds 22a and 22b to the intake ports 18a and 18b becomes long, and the intake air flow is high due to the resonance supercharging effect despite the small intake flow rate. Efficiency is ensured.

  On the other hand, as shown in FIGS. 5A and 5B, when the engine rotates at a high speed, the ECU 32 controls the driving device 49 to control the second communication ports 44a to 44d, 48a to 48d by the on-off valves 47a to 47d and 48a to 48d. While opening 46a-46d, the drive motor 53 is drive-controlled and the deflection | deviation nozzle 50 is rotated, and the opening part 51 is orient | assigned to the 2nd communicating port 44a-44d, 46a-46d side. Therefore, the air introduced into the surge tank 23 from the intake pipe 24 enters the intake passages 41a to 41d and 42a to 42d from the second communication ports 44a to 44d and 46a to 46d, and passes through the intake ports 18a and 18b. Then, it is sucked into the combustion chambers 17a and 17b. Therefore, when the engine is running at high speed, the intake path length from the surge tank 23 through the intake manifolds 22a and 22b to the intake ports 18a and 18b is shortened, and a large amount of intake air is introduced into the combustion chamber early due to the resonance supercharging effect. High intake efficiency is ensured.

  As described above, in the intake system for the multi-cylinder internal combustion engine of the first embodiment, the first intake passages 41a to 41d and 42a to 42d of the intake manifolds 22a and 22b have a long distance to the intake ports 22a and 22b. The communication ports 43a to 43d, 45a to 45d and the second communication ports 44a to 44d and 46a to 46d having a short distance communicate with the surge tank 23, while the downstream end of the intake pipe 24 is connected to the first in the surge tank 23. The communication port 43a-43d, 45a-45d or the second communication port 44a-44d, 46a-46d is located substantially in the middle in the parallel arrangement direction, and the deflection nozzle 50 is rotatably mounted at the tip, and the engine is operating. Accordingly, the direction of the deflecting nozzle 50 is changed, and the first communication ports 43a to 43d, 45a to 45d or the second communication ports 44a to 44d, So that selectively guide to 6a~46d.

  Therefore, since the downstream end of the intake pipe 24 is positioned at the intermediate portion of the surge tank 23, the intake manifolds 22a and 22b are connected to each intake passage from the downstream end of the intake pipe 24 in the surge tank 24. The distance to the entrance is substantially the same, and the half-order component (0.5th-order component) of the intake sound, which is undesirable in terms of timbre, is reduced, and it is possible to improve the intake sound quality by suppressing the occurrence of abnormal intake noise. Further, by changing the length of the intake path according to the operating state of the engine, intake air can be reliably introduced into the combustion chamber by the resonance supercharging effect, and high intake efficiency can be ensured. The intake air flowing into the surge tank 23 from the intake pipe 24 is selectively guided by the deflection nozzle 50 to the first communication ports 43a to 43d, 45a to 45d or the second communication ports 44a to 44d and 46a to 46d. Thus, the engine performance can be improved by controlling the flow of intake air in accordance with the operating state of the engine.

  In Example 1, the opening 51 of the deflection nozzle 50 has a shape that is obliquely curved and cut. However, the shape is not limited to this shape, and the tip portion is bent or a trumpet shape. An opening may be formed on the side surface. Further, the motor 53 for rotating the deflection nozzle 50 is provided in the surge tank. However, the connecting portion between the intake pipe 24 and the deflection nozzle 50 is disposed outside the surge tank 23, and the drive motor 53 is provided here. In this case, the drive motor 53 can ensure a smooth intake air flow without becoming an intake resistance, and the durability and maintainability of the drive motor 53 can be improved.

  FIG. 7 is a partially cutaway front view showing an intake device of a multi-cylinder internal combustion engine according to Embodiment 2 of the present invention. In addition, the same code | symbol is attached | subjected to the member which has the same function as what was demonstrated in the Example mentioned above, and the overlapping description is abbreviate | omitted.

  In the intake system of the multi-cylinder internal combustion engine of the second embodiment, as shown in FIG. 7, the downstream end portion of the intake pipe 24 is connected to a surge tank 23, and the surge tank 23 includes eight intake air in the intake manifolds 22a and 22b. The passages 41a to 41d and 42a to 42d are connected to the intake ports 18a and 18b. The intake pipe 24 has a downstream end located substantially in the middle of the first communication ports 43a to 43d, 45a to 45d or the second communication ports 44a to 44d and 46a to 46d in the surge tank 23. ing. Then, the intake air introduced into the surge tank 23 is sent to the first communication ports 43a to 43d, 45a to 45d or the second communication ports 44a to 44d, 46a to the surge tank 23 facing the downstream end of the intake pipe 24. A deflection plate 60 as a guide means for selectively guiding to 46d is mounted.

  The deflecting plate 60 has a base end portion rotatably supported by a horizontal rotating shaft 61 in the surge tank 23, and a tip end portion facing the downstream end portion side of the intake pipe 24. The deflection plate 60 has a surface so that the intake air flowing into the surge tank 23 from the intake pipe 24 flows to the first communication ports 43a to 43d, 45a to 45d or the second communication ports 44a to 44d and 46a to 46d. Is curved with respect to the axial direction of the rotation shaft 61 and is curved with respect to the front-rear direction orthogonal to the rotation shaft 61. The deflecting plate 60 can be rotated by a predetermined angle by a driving device (not shown) provided at the shaft end of the rotating shaft 61, and the ECU 32 can be driven and controlled in accordance with the engine operating state.

  That is, when the engine is running at a low speed, the ECU 32 rotates the deflector plate 60 upward as shown by a solid line in FIG. 7 so that the intake air from the intake pipe 24 is moved to the first communication ports 43a to 43d and 45a to 45d. In order to guide, this intake air is taken into the combustion chambers 17a and 17b through a long intake passage, and high intake efficiency is ensured by the resonance supercharging effect despite the small intake flow rate. On the other hand, when the engine rotates at a high speed, the ECU 32 rotates the deflector plate 60 downward as shown by a two-dot chain line in FIG. 7 to draw the intake air from the intake pipe 24 into the second communication ports 44a to 44d, 46a to 46d. Therefore, the intake air is taken into the combustion chambers 17a and 17b through a short intake path, and a large amount of intake air is introduced into the combustion chamber at an early stage due to the resonance supercharging effect, thereby ensuring high intake efficiency. The

  As described above, in the intake device of the multi-cylinder internal combustion engine of the second embodiment, the downstream end portion of the intake pipe 24 is connected to the first communication ports 43a to 43d, 45a to 45d or the second communication port 44a in the surge tank 23. To 44d, 46a to 46d, which are located approximately in the middle of the juxtaposed direction, and the intake air introduced into the surge tank 23 is supplied to the surge tank 23 facing the front end portion through the first communication ports 43a to 43d, 45a to 45d. Alternatively, a deflection plate 60 that selectively guides the second communication ports 44a to 44d and 46a to 46d is mounted.

  Therefore, the intake air flowing into the surge tank 23 from the intake pipe 24 is selectively guided to the first communication ports 43a to 43d, 45a to 45d or the second communication ports 44a to 44d and 46a to 46d by the deflector plate 60. Thus, the engine performance can be improved by controlling the flow of intake air in accordance with the operating state of the engine. Further, since the deflection plate 60 is provided in the surge tank, it is not necessary to change the configuration of the intake pipe 24, and the structure can be simplified.

  In each of the above-described embodiments, the multi-cylinder internal combustion engine of the present invention has been described as a V-type 8-cylinder engine. However, the number of cylinders is not limited to this, and is not limited to a V-type engine. It may be an engine.

  In addition, the first communication ports 43a to 43d and 45a to 45d and the second communication ports 44a to 44d and 46a to 46d in the intake passages 41a to 41d and 42a to 42d are provided so as to face each other vertically. If this intake path can be ensured, the positional relationship is not limited to this, and it may be upside down, provided on the left and right, or provided side by side. Further, the number of communication ports is not limited to two for low rotation and high rotation, but may be three or more including medium rotation.

  Furthermore, although the guide means of the present invention is the deflection nozzle 50 or the deflection plate 60, the present invention is not limited to these configurations, and other configurations may be used.

  As described above, the intake device of the multi-cylinder internal combustion engine according to the present invention is configured to smoothly flow the intake air flowing into the surge tank from the intake pipe into the intake passage according to the operating state of the internal combustion engine. It is also useful for an intake device of a multi-cylinder internal combustion engine of the form.

1 is a partially cutaway front view showing an intake device for a multi-cylinder internal combustion engine according to Embodiment 1 of the present invention. 1 is a partially cutaway plan view illustrating an intake device for a multi-cylinder internal combustion engine according to a first embodiment. FIG. 3 is a sectional view taken along line III-III in FIG. 2. It is a schematic front view showing the intake device at the time of low rotation of an internal combustion engine. It is a schematic side view showing the intake device at the time of low rotation of a fuel engine. It is a schematic front view showing the intake device at the time of high rotation of an internal combustion engine. It is a schematic side view showing the intake device at the time of high rotation of an internal combustion engine. 1 is a schematic view of a V-type 8-cylinder engine to which an intake device for a multi-cylinder internal combustion engine of Example 1 is applied. It is a partially cutaway front view showing the intake device of the multi-cylinder internal combustion engine according to the second embodiment of the present invention.

Explanation of symbols

11 Cylinder block 17a, 17b Combustion chamber 18a, 18b Intake port 30 Exhaust pipe 22a, 22b Intake manifold 23 Surge tank 24 Intake pipe 32 Electronic control unit (ECU)
41a-41d, 42a-42d Intake passages 43a-43d, 45a-45d First communication port 44a-44d, 46a-46d Second communication port 47a-47d, 48a-48d On-off valve 49 Drive device 50 Deflection nozzle (guide means)
51 opening 53 drive motor 60 deflection plate (guide means)
61 Rotating shaft

Claims (4)

  In the intake system for an internal combustion engine, the downstream end of the intake pipe is connected to a surge tank, and the surge tank is connected to each intake port of the internal combustion engine via a plurality of intake passages. While the first communication port and the second communication port having different distances to the intake port communicate with the surge tank, the downstream end of the intake pipe has the first communication port or the second communication port in the surge tank. A guide that is located substantially in the middle in the direction in which the ports are arranged side by side and selectively guides the intake air introduced into the surge tank from the downstream end of the intake pipe to the first communication port or the second communication port. An intake device for a multi-cylinder internal combustion engine, characterized in that means are provided.   2. The intake device for a multi-cylinder internal combustion engine according to claim 1, wherein the guide means guides intake air to the first communication port having a long distance to the intake port when the internal combustion engine rotates at a low speed. An intake system for a multi-cylinder internal combustion engine, wherein the intake air is guided to the second communication port having a short distance to the intake port during high rotation.   3. The intake system for a multi-cylinder internal combustion engine according to claim 1, wherein the guide means is a deflection nozzle that is rotatably mounted at a downstream end portion of the intake pipe, and depends on an operating state of the internal combustion engine. An intake system for a multi-cylinder internal combustion engine, wherein the direction of the deflection nozzle is changed to change the guide direction of intake air. 3. The intake system for a multi-cylinder internal combustion engine according to claim 1 or 2, wherein the guide means is a deflection plate that is rotatably mounted facing the downstream end of the intake pipe, and operates the internal combustion engine. An intake system for a multi-cylinder internal combustion engine, wherein the direction of the deflecting plate is changed according to the state to change the guide direction of intake air.

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