JP2015025395A - Intake device of engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an intake device of an engine capable of surely sucking water content and oil content accumulated in a lower portion of a chamber and introducing the same to a cylinder of an engine.SOLUTION: An intake device (18) has a chamber (58) provided with an inflow port (60) for allowing intake air to flow in, a throttle valve (62) disposed at an upstream side of the inflow port, a throttle intake passage (64) formed while decreasing its flow channel cross-section from the chamber, an enlarged intake passage (70) communicating the throttle intake passage with a cylinder (2), and a suction passage (74) communicating a lower portion of the chamber with the throttle intake passage. The suction passage includes a throttle communication passage (76) for communicating an upstream side of the throttle valve with the throttle intake passage, and a chamber communication passage (78) for communicating the lower portion of the chamber with an intermediate portion of the throttle communication passage. The throttle communication passage includes a throttle portion (106) having a flow channel cross-section reduced toward a connecting portion with the chamber communication passage.

Description

  The present invention relates to an intake device for an engine, and more particularly to an intake device that introduces intake air into a plurality of cylinders of an engine.

2. Description of the Related Art Conventionally, an intake device is known in which a chamber for equalizing the supply amount and supply pressure of intake air to a plurality of cylinders is provided in the middle of an intake passage for introducing intake air into a cylinder of an engine.
Since the blow-in gas and EGR (Exhaust Gas Recirculation) gas are recirculated in the intake air flowing into the chamber, moisture and oil contained in these gases are condensed in the chamber and are formed in the lower part of the chamber. May accumulate. If the moisture or oil accumulated in the lower part of the chamber is left as described above, problems such as freezing and blockage of the intake flow path occur. Therefore, it is necessary to suck out the moisture and oil from the chamber and introduce them into the engine cylinder together with the intake air.

In view of this, an intake device is used in which water and oil accumulated in the lower part of the chamber are sucked into the cylinder of the engine.
For example, Patent Document 1 discloses an intake manifold that allows an engine to suck water and oil below a surge tank (chamber). The intake manifold of Patent Document 1 includes a surge tank, a plurality of intake branches that are connected to the surge tank and guide intake air to each of a plurality of cylinders of an engine, and a plurality of communication pipes that connect the surge tank and each intake branch. And have. Water and oil in the lower part of the surge tank are sucked up into each intake branch through this communication pipe by the pressure difference between the surge tank and each intake branch, and sucked into the engine.

  Further, in Patent Document 2, in an intake manifold similar to Patent Document 1, a communication pipe that communicates an intake flow upstream side of a throttle valve and an intake branch, a discharge pipe that communicates a lower part of a surge tank and a communication pipe, An intake manifold is disclosed. In the intake manifold of Patent Document 2, water and oil below the surge tank are pushed into the communication pipe via the discharge pipe, and are generated between the intake flow upstream side and the intake flow downstream side of the throttle valve. Due to the differential pressure, water and oil inside the communication pipe are pumped to the intake branch.

JP 2011-185147 A JP 2012-87773 A

  However, in the intake manifold of Patent Document 1 described above, there is a problem that moisture and oil cannot be reliably sucked up from the surge tank because the differential pressure between the surge tank and each intake branch is not sufficient. Further, since a communication pipe for sucking up moisture and oil from the surge tank is provided for each intake branch, the structure of the intake manifold is complicated.

  Further, in the intake manifold described in Patent Document 2 described above, since the differential pressure generated between the intake flow upstream side and the intake flow downstream side of the throttle valve is not sufficient, water and oil inside the communication pipe can be reliably supplied to the intake branch. The problem arises in that it cannot be pumped.

  The present invention has been made to solve the above-described problems of the prior art, and with a simple configuration, moisture and oil accumulated in the lower part of the chamber can be reliably sucked out and introduced into the cylinder of the engine. An object of the present invention is to provide an intake device for an engine.

In order to achieve the above object, an intake device for an engine according to the present invention is an intake device that introduces intake air into a plurality of cylinders of an engine, and an inflow port through which intake air flows is formed. A chamber formed so as to increase the cross-sectional area of the flow path, a throttle valve provided on the upstream side of the inlet of the chamber, and provided so as to extend upward from the chamber, the cross-sectional area of the flow path decreases from the chamber. A throttle intake passage formed in such a manner, an outlet of the throttle intake passage and a plurality of cylinders of the engine communicate with each other, and an enlarged intake passage formed so that a cross-sectional area of the flow passage extends from the throttle intake passage; A suction passage that communicates the lower portion with the downstream portion of the throttle intake passage, and the suction passage communicates the upstream side of the throttle valve with the downstream portion of the throttle intake passage. A communication passage, and a chamber communication passage that communicates a lower portion of the chamber and an intermediate portion of the throttle communication passage. The throttle communication passage is connected on the throttle valve side of the connection portion between the throttle communication passage and the chamber communication passage. The flow path cross-sectional area decreases toward the part, and a throttle part is provided.
In the present invention configured as described above, when the intake air flows into the throttle intake passage from the chamber during the operation of the engine, the flow velocity of the intake air increases and the pressure decreases according to the decrease in the cross-sectional area of the flow passage. A differential pressure is generated between the lower portion and the downstream portion of the throttle intake passage. The suction passage communicates the lower portion of the chamber where the differential pressure is generated with the downstream portion of the throttle intake passage. Moisture and oil accumulated in the lower portion of the chamber can be reliably sucked up from the chamber through the suction passage due to the differential pressure generated between the downstream portion of the intake passage.
Further, since the throttle communication passage communicates the upstream side of the throttle valve where differential pressure is generated during engine operation and the downstream portion of the throttle intake passage, a part of the intake air flowing into the throttle valve is part of the throttle communication passage. And the pressure decreases by passing through the throttle portion of the throttle communication passage. As a result, a differential pressure is generated between the lower portion of the chamber and the intermediate portion of the throttle communication passage. The chamber communication passage communicates the lower portion of the chamber where the differential pressure is generated with the intermediate portion of the throttle communication passage. In addition to the differential pressure between the lower part of the chamber and the downstream part of the throttle intake passage, the water or oil accumulated in the lower part of the chamber is caused by the differential pressure generated between the intermediate part of the throttle communication path and the lower part of the chamber. Can be reliably sucked up from the chamber through the chamber communication passage and the throttle communication passage.

In the present invention, preferably, a part of the throttle communication passage and the chamber communication passage are tubular members in close contact with the outer surface of the chamber.
In the present invention configured as described above, a part of the throttle communication passage and the chamber communication passage are in close contact with the outer surface of the chamber, so that heat can be efficiently absorbed from the intake air flowing into the chamber. Accordingly, even when the water inside the throttle communication passage or the chamber communication passage is frozen at the time of cold start, the ice can be easily melted. Further, a part of the throttle communication passage and the chamber communication passage can be formed by a simple configuration in which the tubular member is brought into close contact with the outer surface of the chamber.

In the present invention, it is preferable that the throttle communication path includes a hose that connects a tubular member in close contact with the outer surface of the chamber and an upstream side of the throttle valve.
In the present invention configured as described above, the upstream side of the throttle valve and the part of the throttle communication passage that is in close contact with the outer surface of the chamber are connected by a hose, so that the upstream side of the throttle valve and the chamber are separated from each other. Even in this case, the upstream side of the throttle valve can be easily connected to a part of the throttle communication passage.

In the present invention, it is preferable that the intake device introduces the intake air supercharged by the supercharger into a plurality of cylinders of the engine including a supercharger that supercharges intake air including the recirculated exhaust gas. The chamber is provided downstream of the supercharger.
In the present invention configured as described above, the intake air compressed by the supercharger flows into the chamber after the exhaust gas containing a large amount of moisture is introduced. The moisture contained in the intake air is condensed in the chamber. In this case, the condensed water can be reliably sucked up from the chamber through the suction passage and introduced into each cylinder of the engine.

In the present invention, it is preferable that the intake device introduces the intake air cooled by the intercooler into a plurality of cylinders of an engine provided with an intercooler that cools the intake air. To accommodate.
In the present invention configured as described above, the chamber accommodates an intercooler that cools the intake air. Therefore, the intake air flowing into the chamber is cooled by the intercooler, and moisture contained in the intake air is condensed in the chamber. However, the condensed water can be reliably sucked up from the chamber through the suction passage and introduced into each cylinder of the engine.

  According to the present invention, with a simple configuration, moisture and oil accumulated in the lower portion of the chamber can be reliably sucked out and introduced into the cylinder of the engine.

It is a schematic block diagram which shows the structure of the intake-exhaust system of the engine to which the intake device by embodiment of this invention was applied. It is the perspective view which looked at the intake device by embodiment of this invention from the diagonally upper side opposite to an intake port. It is the front view which looked at the intake device by embodiment of this invention from the intake port side. FIG. 4 is an IV-IV arrow view of the intake device shown in FIG. 3. FIG. 5 is a VV arrow view of the intake device shown in FIG. 3. It is sectional drawing of the aspirator of the suction path by embodiment of this invention. It is sectional drawing of the introductory pipe | tube of the suction passage by embodiment of this invention.

Hereinafter, an engine intake device according to an embodiment of the present invention will be described with reference to the accompanying drawings.
First, the configuration of an intake / exhaust system of an engine to which an intake device according to an embodiment of the present invention is applied will be described with reference to FIG. FIG. 1 is a schematic configuration diagram showing a configuration of an intake / exhaust system of an engine to which an intake device according to an embodiment of the present invention is applied. In this embodiment, the case where the intake device according to the present invention is applied to a four-cylinder diesel engine will be described.

  As shown in FIG. 1, reference numeral 1 denotes an engine, and the engine 1 introduces an engine body 4 having a cylinder 2 that takes out power by burning a mixture of fuel and intake air, and introduces intake air into the cylinder 2. It has an intake passage 6 and an exhaust passage 8 through which exhaust generated in the cylinder 2 is discharged into the atmosphere.

  First, the intake passage 6 includes an air cleaner 10 that introduces outside air and removes dust and dirt. A compressor 14 a of a supercharger 14 that supercharges intake air is connected to the downstream side of the air cleaner 10 via an intake pipe 12. Further, an intake device 18 is connected to the downstream side of the compressor 14 a of the supercharger 14 via an intake pipe 16. Inside the intake device 18, an intercooler 20 that cools the intake air flowing into the intake device 18 is accommodated. A water pump 24 is connected to the intercooler 20 via a cooling pipe 22, and cooling water is supplied from the water pump 24 to the intercooler 20. The cooling water supplied from the water pump circulates inside the intercooler 20, and the intake air is cooled by the temperature difference between the cooling water and the intake air. A downstream side of the intake device 18 is connected to an intake port 26 provided in the engine body 4, and intake air is introduced into the cylinder 2 through the intake port 26.

  Next, the exhaust path 8 includes an exhaust pipe 30 connected to an exhaust port 28 provided in the engine body 4, and exhaust gas is introduced from the cylinder 2 into the exhaust pipe 30 via the exhaust port 28. A turbine 14b that drives the compressor 14a of the supercharger 14 using the internal energy of the exhaust is connected to the downstream side of the exhaust pipe 30. Further, on the downstream side of the turbine 14 b of the supercharger 14, an oxidation catalyst 34 that removes CO and HC in the exhaust and a DPF 36 (Diesel Particulate Filter) that removes particulate matter in the exhaust are disposed via the exhaust pipe 32. Are connected. A silencer 40 is connected to the downstream side of the DPF 36 through an exhaust pipe 38, and the outlet of the silencer 40 is opened toward the atmosphere.

  Further, the engine 1 recirculates the high-pressure exhaust gas immediately after being discharged from the cylinder 2 to the intake passage 6 and the low-pressure exhaust gas after passing through the oxidation catalyst 34 and the DPF 36 to the intake passage 6. And a low-pressure EGR device 44.

  The high-pressure EGR device 42 includes a high-pressure EGR pipe 46 that connects an intermediate portion of the exhaust pipe 30 that connects the exhaust port 28 and the turbine 14 b of the supercharger 14 and a downstream portion of the intake device 18. A high-pressure EGR cooler 48 that cools the high-pressure EGR gas that flows through the high-pressure EGR pipe 46 is provided at an intermediate portion of the high-pressure EGR pipe 46. A high pressure EGR valve 50 for adjusting the flow rate of the high pressure EGR gas is provided downstream of the high pressure EGR pipe 46.

  The low pressure EGR device 44 includes a low pressure EGR pipe 52 that connects an intermediate portion of the exhaust pipe 38 that connects the DPF 36 and the silencer 40 and an intermediate portion of the intake pipe 12 that connects the air cleaner 10 and the compressor 14 a of the supercharger 14. It has. A low pressure EGR cooler 54 for cooling the low pressure EGR gas flowing through the low pressure EGR pipe 52 is provided at an intermediate portion of the low pressure EGR pipe 52. A low pressure EGR valve 56 for adjusting the flow rate of the low pressure EGR gas is provided downstream of the low pressure EGR pipe 52.

  Next, the configuration of the intake device 18 according to the embodiment of the present invention will be described with reference to FIGS. 1 to 3. FIG. 2 is a perspective view of the intake device 18 according to the embodiment of the present invention as viewed from the diagonally upper side opposite to the intake port 26, and FIG. 3 is a view of the intake device 18 according to the embodiment of the present invention from the intake port 26 side. FIG. These vertical directions in FIGS. 2 and 3 correspond to the vertical direction of the intake device 18 in use.

First, as shown in FIGS. 1 and 2, the intake device 18 includes a box-shaped resin chamber 58 connected to the intake pipe 16 on the downstream side of the supercharger 14. An inlet 60 to which the intake pipe 16 is connected is formed on the side wall surface of the chamber 58, and the chamber 58 is formed so that the flow path cross-sectional area is enlarged from the inlet 60. Intake air flows from the intake pipe 16 into the chamber 58 through the inflow port 60.
The intake pipe 16 connected to the inlet 60 of the chamber 58 is provided with a throttle valve 62 for adjusting the flow rate of the intake air.

  The intake device 18 includes a throttle intake passage 64 provided so as to extend upward from the chamber 58. The throttle intake passage 64 is connected to an outlet 66 formed on the upper wall surface of the chamber 58, and is formed so that the cross-sectional area of the flow path decreases from the chamber 58. The intake air flows from the chamber 58 into the throttle intake passage 64 through the outlet 66. An exhaust inlet 68 to which the high pressure EGR pipe 46 is connected is formed at an intermediate portion of the throttle intake passage 64, and high pressure EGR gas is introduced into the throttle intake passage 64 through the exhaust inlet 68. The

  Further, an enlarged intake passage 70 that communicates the outlet of the throttle intake passage 64 and the intake ports 26 of the plurality of cylinders 2 is provided on the downstream side of the throttle intake passage 64. The enlarged intake passage 70 is connected to the upper end (downstream end) of the throttle intake passage 64 and is formed so that the cross-sectional area of the flow passage extends from the throttle intake passage 64. In the present embodiment, the enlarged intake passage 70 is formed so that the cross-sectional area of the flow passage expands in the horizontal direction from the upper end (downstream end) of the throttle intake passage 64. The engine 1 to which the intake device 18 according to this embodiment is applied has four cylinders 2, and two intake ports 26 are provided in each cylinder 2. Therefore, as shown in FIG. 3, the enlarged intake passage 70 is formed with eight connection ports 72 connected to the intake ports 26.

  As shown in FIGS. 1 and 3, the intake device 18 communicates the lower portion of the chamber 58 with the downstream portion of the throttle intake passage 64, and has a suction passage 74 that sucks up moisture and oil accumulated in the lower portion of the chamber 58. I have. The suction passage 74 has a throttle communication passage 76 that communicates the upstream side of the throttle valve 62 and the downstream portion of the throttle intake passage 64, and a chamber communication passage 78 that communicates the lower portion of the chamber 58 and the intermediate portion of the throttle communication passage 76. And.

  Next, the suction passage 74 of the intake device 18 according to the embodiment of the present invention will be described with reference to FIGS. 4 is an IV-IV arrow view of the intake device 18 shown in FIG. 3, FIG. 5 is a VV arrow view of the intake device 18 shown in FIG. 3, and FIG. 7 is a cross-sectional view of the aspirator of the suction passage 74 according to the embodiment, and FIG. 7 is a cross-sectional view of the introduction pipe of the suction passage 74 according to the embodiment of the present invention as viewed from above.

  First, as shown in FIGS. 3 and 4, the chamber communication passage 78 is provided along the outer surface of the chamber 58 on the intake port 26 side so as to extend upward from the lower portion of the chamber 58. The chamber communication passage 78 is formed by welding a resin tubular member 80 to the outer surface of the chamber 58. The lower end of the tubular member 80 is sealed, and the upper end is connected to the throttle communication passage 76. A through hole 82 is formed in the wall surface of the chamber 58 at the lower end portion of the chamber communication passage 78, whereby the inside of the chamber communication passage 78 and the inside of the chamber 58 communicate with each other.

  The throttle communication passage 76 is provided so as to extend in a substantially horizontal direction from the upstream side of the throttle valve 62 to the lower surface of the downstream portion of the throttle intake passage 64. The throttle communication passage 76 includes an introduction pipe 84 for introducing intake air from the intake pipe 16 on the upstream side of the throttle valve 62, an acid resistant rubber hose 86 connected to the introduction pipe 84, the hose 86, and the chamber communication passage. A T-shaped aspirator 88 to which 78 is connected, and an in-wall passage 90 formed in the wall of the chamber 58 so that the aspirator 88 and the downstream portion of the throttle intake passage 64 communicate with each other.

As shown in FIGS. 4 and 5, the connecting portion 92 between the in-wall passage 90 and the downstream portion of the throttle intake passage 64 protrudes into the throttle intake passage 64 from the bottom surface of the downstream end of the throttle intake passage 64. In the side surface of the raised connection portion 92, two openings 94 are formed in the direction in which the enlarged intake passage 70 expands toward the plurality of intake ports 26 (the left-right direction in FIG. 5). The intra-wall passage 90 and the throttle intake passage 64 communicate with each other through the opening 94.
As shown in FIG. 4, the exhaust inlet 68 through which the high-pressure EGR gas recirculates is connected to the throttle intake passage 64 upstream of the connection portion 92 between the throttle intake passage 64 and the in-wall passage 90 of the suction passage 74. The high-pressure EGR gas is formed and flows from the exhaust inlet 68 toward the upstream position of the connecting portion 92 between the throttle intake passage 64 and the in-wall passage 90.

  Next, as shown in FIG. 6, the T-shaped aspirator 88 includes a hose connection portion 96 to which the hose 86 is connected, a chamber communication passage connection portion 98 to which the upper end of the chamber communication passage 78 is connected, and an in-wall passage. 90, and a T-branch portion 102 to which the hose connection portion 96, the chamber communication passage connection portion 98, and the in-wall passage connection portion 100 are connected. The aspirator 88 is integrally formed of resin.

The hose connection portion 96 is a tube having an outer diameter that is substantially the same as the inner diameter of the hose 86. Similarly to the chamber communication passage 78, the chamber communication passage connection portion 98 and the in-wall passage connection portion 100 are formed by welding a resin tubular member 104 to the outer surface of the chamber 58.
Further, between the hose connection portion 96 and the T-shaped branch portion 102, a throttle portion 106 is formed in which the flow path cross-sectional area decreases from the hose connection portion 96 toward the branch portion.

  Next, as shown in FIG. 7, the introduction pipe 84 is provided on the upstream side of the throttle valve 62, and one end protrudes inside the intake pipe 16 and the other end is outside the intake pipe 16. It is formed so as to protrude. The leading end surface of the introduction pipe 84 protruding inside the intake pipe 16 is formed so as to incline toward the upstream side of the intake pipe 16, and a part of the intake air flowing inside the intake pipe 16 is the leading end face. It is introduced into the introduction pipe 84 through the opening 94. Further, the end portion of the introduction pipe 84 that protrudes outside the intake pipe 16 has an outer diameter that is substantially the same as the inner diameter of the hose 86, so that the hose 86 is connected thereto.

Next, further modifications of the embodiment of the present invention will be described.
In the above-described embodiment, the case where the intake device 18 according to the present invention is applied to a four-cylinder diesel engine has been described. However, the intake device 18 according to the present invention is also applied to a diesel engine or a gasoline engine having a different number of cylinders. Can be applied.

  Further, in the above-described embodiment, in the side surface of the connecting portion 92 between the in-wall passage 90 and the downstream portion of the throttle intake passage 64, the enlarged intake passage 70 expands toward the plurality of intake ports 26. Although it has been described that two openings 94 are formed, three or more openings 94 may be formed.

  Next, the effect of the intake device 18 of the engine 1 according to the above-described embodiment of the present invention and the modification of the embodiment of the present invention will be described.

First, when the intake air flows into the throttle intake passage 64 from the chamber 58 during the operation of the engine 1, the flow velocity of the intake air increases and the pressure decreases according to the decrease in the cross-sectional area of the flow path. In this embodiment, the suction passage 74 of the intake device 18 communicates the lower portion of the chamber 58 where the differential pressure is generated with the downstream portion of the throttle intake passage 64. Therefore, moisture and oil accumulated in the lower portion of the chamber 58 are reliably discharged from the chamber 58 via the suction passage 74 due to the differential pressure generated between the lower portion of the chamber 58 and the downstream portion of the throttle intake passage 64. Can suck up.
Further, since the throttle communication passage 76 communicates the upstream side of the throttle valve 62 where a differential pressure is generated during operation of the engine 1 and the downstream portion of the throttle intake passage 64, a part of the intake air flowing into the throttle valve 62 is communicated. Flows into the throttle communication passage 76 and passes through the throttle portion 106 of the throttle communication passage 76, whereby the pressure is reduced. As a result, a differential pressure is generated between the lower portion of the chamber 58 and the intermediate portion of the throttle communication passage 76, and the chamber communication passage 78 connects the lower portion of the chamber 58 where the differential pressure is generated and the intermediate portion of the throttle communication passage 76. Because of the communication, in addition to the differential pressure between the lower portion of the chamber 58 and the downstream portion of the throttle intake passage 64, the differential pressure generated between the intermediate portion of the throttle communication passage 76 and the lower portion of the chamber 58 Moisture and oil accumulated in the lower part of the chamber 58 can be reliably sucked up from the chamber 58 via the chamber communication passage 78 and the throttle communication passage 76.

  In this embodiment, part of the throttle communication passage 76 and the chamber communication passage 78 are in close contact with the outer surface of the chamber 58, so that heat can be efficiently absorbed from the intake air flowing into the chamber 58. As a result, even when the water inside the throttle communication passage 76 and the chamber communication passage 78 is frozen at the time of cold start, the ice can be easily melted. Further, a part of the throttle communication passage 76 and the chamber communication passage 78 can be formed with a simple configuration in which the tubular members 80 and 104 are brought into close contact with the outer surface of the chamber 58.

  In the present embodiment, the upstream side of the throttle valve 62 and a part of the throttle communication passage 76 that is in close contact with the outer surface of the chamber 58 are connected by the hose 86, so Even when the distance between them is far, the upstream side of the throttle valve 62 and a part of the throttle communication passage 76 can be easily connected.

  In the present embodiment, low-pressure EGR gas containing a large amount of moisture is first introduced from the low-pressure EGR pipe 52 into the intake air introduced into the intake passage 6 via the air cleaner 10. The intake air into which the low-pressure EGR gas has been introduced is compressed by the compressor 14 a of the supercharger 14 and then flows into the chamber 58. That is, the intake air containing a large amount of moisture flows into the chamber 58 and the moisture contained in the intake air condenses in the chamber 58. The condensed water is reliably discharged from the chamber 58 via the suction passage 74 of the present embodiment. It can be sucked up and introduced into each cylinder 2 of the engine 1.

  In the present embodiment, the chamber 58 houses the intercooler 20 that cools the intake air. Therefore, the intake air that has flowed into the chamber 58 is cooled by the intercooler 20, and moisture contained in the intake air is contained in the chamber 58. Although condensed, the condensed water can be reliably sucked up from the chamber 58 via the suction passage 74 of the present embodiment and introduced into each cylinder 2 of the engine 1.

DESCRIPTION OF SYMBOLS 1 Engine 2 Cylinder 4 Engine main body 6 Intake passage 8 Exhaust passage 14 Supercharger 18 Intake device 20 Intercooler 42 High pressure EGR device 44 Low pressure EGR device 58 Chamber 60 Inlet 62 Throttle valve 64 Throttle intake passage 68 Exhaust inflow inlet 70 Expanded intake air Passage 72 Connection port 74 Suction passage 76 Throttle communication passage 78 Chamber communication passage 80, 104 Tubular member 86 Hose 88 Aspirator 90 In-wall passage 92 Connection portion 94 Opening 106 Restriction portion

Claims (5)

An intake device that introduces intake air into a plurality of cylinders of an engine,
A chamber formed so that an inflow port into which intake air flows is formed, and a cross-sectional area of the flow channel is enlarged from the inflow port;
A throttle valve provided on the upstream side of the inlet of the chamber;
A throttle intake passage provided so as to extend upward from the chamber, and formed so that a cross-sectional area of the flow path is reduced from the chamber;
An enlarged intake passage formed such that an outlet of the throttle intake passage and a plurality of cylinders of the engine communicate with each other, and a cross-sectional area of the flow passage is enlarged from the throttle intake passage;
A suction passage communicating the lower portion of the chamber and the downstream portion of the throttle intake passage,
The suction passage includes a throttle communication passage that communicates the upstream side of the throttle valve and the downstream portion of the throttle intake passage, and a chamber communication passage that communicates a lower portion of the chamber and an intermediate portion of the throttle communication passage. ,
The throttle communication passage includes a throttle portion whose flow passage cross-sectional area decreases toward the connection portion on the throttle valve side of the connection portion between the throttle communication passage and the chamber communication passage. The engine intake system.   2. The engine intake device according to claim 1, wherein a part of the throttle communication passage and the chamber communication passage are tubular members in close contact with an outer surface of the chamber.   3. The engine intake device according to claim 2, wherein the throttle communication passage includes a hose connecting a tubular member that is in close contact with an outer surface of the chamber and an upstream side of the throttle valve. The intake device introduces intake air supercharged by the supercharger into a plurality of cylinders of an engine provided with a supercharger that supercharges intake air including recirculated exhaust gas,
The engine intake device according to any one of claims 1 to 3, wherein the chamber is provided downstream of the supercharger. The intake device introduces intake air cooled by the intercooler into a plurality of cylinders of an engine provided with an intercooler for cooling intake air,
The engine intake device according to any one of claims 1 to 4, wherein the chamber accommodates the intercooler.

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