JP6131794B2 - Engine intake system - Google Patents

Description

  The present invention relates to an intake device for an engine mounted on a vehicle such as an automobile, and more particularly to a technique for sucking out water or oil from a lower portion of a chamber provided in an intake passage.

  FIG. 1 schematically shows an example of this type of intake device. In the figure, 100 is an engine, 101 is a chamber, and 102 is an intercooler.

  The chamber 101 and the intercooler 102 are arranged in the middle of an intake passage 103 that introduces intake air into each cylinder 100 a of the engine 100. The intake air is cooled by the intercooler 102, homogenized and equalized in the chamber 101, and then introduced into each cylinder 100a.

  Along with such an intake device, a blow-by gas recirculation device or an exhaust gas recirculation device (EGR device) may be attached to the engine 100. The blow-by gas recirculation device recirculates the blow-by gas to the intake air, and the EGR device recirculates a part of the exhaust gas to the intake air.

  Since blow-by gas and exhaust gas contain moisture, oil, carbon, and the like, when a blow-by gas recirculation device or EGR device is attached, the moisture, oil, carbon, and the like are also brought into the intake air. Therefore, when the temperature of the intake air decreases due to cooling in the intercooler 102 or expansion in the chamber 101, moisture in the intake air is condensed and water is generated in the intake passage 103. As a result, water tends to collect and collect in the lower part of the lower chamber 101.

  In addition, the oil component brought into the intake air is pushed away by the intake air and flows into the chamber 101 along the inner wall surface of the intake passage 103. As a result, oil tends to collect and collect in the lower part of the lower chamber 101. The carbon brought into the intake air adheres to the inner surface of the intake passage 103 or mixes with water or oil, causing dirt.

  If a large amount of water or oil accumulates in the lower portion of the chamber 101, there is a possibility that a malfunction may occur in the intake passage 103 due to freezing or carbon accumulation, or it may flow into the cylinder 100a at a stroke during operation and cause a malfunction in the engine 100.

  Therefore, it has been proposed to suck out water or oil (also referred to as residual liquid) that accumulates in the lower part of the chamber 101 so that the residual liquid does not accumulate in the lower part of the chamber 101 (for example, Patent Documents 1 and 2).

  Patent Document 1 discloses an intake manifold provided with an intake branch that leads to the cylinder of an engine connected to the downstream side of a surge tank (chamber) and an elongated communication pipe that communicates with a lower portion of the surge tank. . In this intake manifold, due to the differential pressure between the lower part of the surge tank and the intake branch, the residual liquid in the lower part of the surge tank is sucked into the intake branch through the communication pipe.

  In Patent Document 2, the lower side of the surge tank is bypassed, the communication pipe communicates with the upstream side of the throttle valve and the intake branch, and extends downward from the surge tank and communicates with the lower part of the surge tank and the communication pipe. There is disclosed an intake device that includes a discharge pipe, an open / close valve that is disposed upstream of the communication pipe and that opens and closes the communication pipe, and a control device that opens and controls the open / close valve during deceleration.

  In this intake system, a differential pressure is generated between the upstream side (high pressure) of the throttle valve (high pressure) and the intake branch (low pressure) by opening the open / close valve during deceleration. Therefore, the differential pressure is used to communicate with the exhaust pipe. The residual liquid accumulated in the pipe is pumped to the intake branch so that the residual liquid can be sucked out from the lower part of the chamber.

JP 2011-185147 A JP 2012-87773 A

  In the case of the intake manifold of Patent Document 1, since the differential pressure obtained is small in structure and directly affected by the operating state of the engine, the differential pressure between the surge tank and the intake branch is not stable. is there. Therefore, there is a possibility that the suction of the residual liquid becomes insufficient.

  In that regard, in the case of the intake device of Patent Document 2, the residual liquid is pumped using the differential pressure generated between the upstream and downstream, so that the residual liquid can be sucked out more stably than the intake manifold of Patent Document 1. Can do.

  However, the intake device of Patent Document 2 has many problems such as a complicated structure and a possibility that residual liquid may be ejected to the surge tank unless the backflow to the surge tank side is prevented. In Patent Document 2, a check valve and a second opening / closing valve are installed in the exhaust pipe to prevent backflow, but the structure is further complicated.

  In particular, in a diesel engine, the throttle valve is often fully opened during the operation period, and it is difficult to obtain a large pressure difference between the upstream side of the throttle valve and the intake branch. Therefore, in the case of the intake device of Patent Document 2, there is a problem that the effect is not sufficiently obtained in a diesel engine.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an engine intake device that can stably suck out water and oil accumulated in a lower portion of a chamber with a simple configuration.

  The intake device of the present disclosure is an air supply device that introduces intake air into a cylinder of an engine. The intake device has an inlet through which intake air flows, a chamber having a cross-sectional area larger than the inlet, an upstream intake passage connected to the inlet and leading intake air to the inlet. A downstream intake passage that is connected to the outlet of the chamber and guides intake air to the cylinder; a throttle valve that is disposed in the upstream intake passage and changes the opening of the flow path; and a residue that accumulates in a lower portion of the chamber And a thin tubular suction passage for sucking out the liquid.

  The suction passage bypasses the chamber and communicates with an upstream connection portion located upstream of the throttle valve in the upstream intake passage and a downstream connection portion located in the downstream intake passage. A main passage, a lower portion of the chamber, and a sub-passage communicating with the main passage. The main passage has an intake introduction portion that protrudes from an inner wall surface of the upstream intake passage at the upstream connection portion and has an opening for introducing intake air, the opening toward the upstream side and the inner passage. It is located away from the wall surface toward the center of the upstream intake passage.

When the downstream end of the opening located on the downstream side and the upstream end located on the upstream side are viewed with respect to the direction in which the intake air flows, the downstream end is the upstream end. Rather than the inner wall surface to the center side of the upstream intake passage.

  That is, in this air supply device, the main passage of the suction passage for sucking out the remaining liquid accumulated in the lower portion of the chamber has an upstream connection portion upstream of the throttle valve that changes the internal pressure and a downstream connection portion downstream of the chamber. To the lower part of the chamber through a secondary passage. An intake air introduction portion for introducing intake air into the main passage projects from the inner wall surface of the upstream intake passage, and the opening for introducing the intake air faces the upstream side and is spaced from the inner wall surface to the center side of the upstream intake passage. doing.

  Therefore, not only when the flow path is throttled by the throttle valve and a sufficient differential pressure is obtained between the upstream connection site on the upstream side and the downstream connection site on the downstream side of the chamber, Even when the flow path is opened and a sufficient differential pressure cannot be obtained with the downstream connection portion on the downstream side of the chamber, the intake air can be introduced into the opening by the dynamic pressure, so that the suction passage can be stably Inhalation can be introduced.

  As a result, it is possible to stably suck out the remaining liquid accumulated in the lower portion of the chamber, though it has a simple configuration.

In the above air supply device, the downstream end of the opening for introducing the intake air is located closer to the center of the upstream intake passage than the upstream end.

If comprised in this way , a big opening can be made to oppose the flow of intake, without disturbing the flow of intake greatly, and dynamic pressure can be used effectively.

  Moreover, it is preferable to provide a weir portion that blocks the inflow of oil into the opening in the intake air introduction portion.

  If it does so, even if oil flows along the inner wall face of an intake passage, it can control that oil flows into an opening along an intake introduction part by a dam part.

  In particular, an advantageous effect can be obtained when the first gas introduction port for introducing the high-pressure EGR gas is provided in a portion upstream of the downstream connection portion in the downstream intake passage.

  That is, since the high-pressure EGR gas contains carbon, there is a possibility that the carbon adheres to and accumulates on the inner wall surface of the downstream side intake passage downstream of the high pressure EGR gas. Therefore, there is a possibility that carbon may adhere to the first gas introduction port and clogging may occur. However, since intake air and residual liquid are constantly ejected from the first gas introduction port, The adhesion of carbon to one gas inlet is suppressed, and the residual liquid can be sucked out stably.

  Further, a supercharger is disposed at a position upstream of the throttle valve in the upstream intake passage, and a second gas introduction port for introducing low-pressure EGR gas is provided by the supercharger in the upstream intake passage. Also, an advantageous effect can be obtained when it is provided at the upstream portion.

  That is, the low-pressure EGR gas introduced into the intake air from the upstream side of the supercharger has a low pressure, and therefore has more moisture than the high-pressure EGR gas. Therefore, when the low-pressure EGR gas is mixed with intake air upstream of the chamber, residual liquid tends to accumulate inside the chamber. However, in this air supply device, the residual liquid is always stably extracted, It is possible to effectively suppress a large amount of residual liquid from accumulating in the lower portion of the chamber.

  Furthermore, it is effective when the third gas introduction port for introducing the blow-by gas is provided in a portion upstream of the upstream connection portion in the upstream intake passage.

  That is, since oil is contained in the blow-by gas, it is easy for oil to flow into the opening. However, since the form and arrangement of the intake air inlet are devised, it is possible to effectively prevent the oil from flowing into the opening.

  Further, an intercooler for cooling the intake air may be accommodated in the chamber.

  In this case, residual liquid is likely to be generated on the downstream side of the intercooler. However, by accommodating the intercooler in the chamber, the residual liquid can be collected in the lower portion of the chamber and efficiently removed from the intake passage.

  For example, the sub-passage communicates with the main passage at a communication portion located higher than the lower portion of the chamber, and forms a reduced pressure state at the communication portion using intake air flowing through the main passage. An aspirator structure is preferably provided.

  Then, since the negative pressure generated in the communication part can be used for suction, the residual liquid can be efficiently sucked out even if the amount of intake air flowing through the suction passage is small, and the communication part is connected to the lower part of the chamber. However, the backflow of the residual liquid can be effectively suppressed while having a simple structure.

  Particularly in this case, it is preferable that the area of the projected view of the opening as seen from the direction in which the intake air flows has a size equal to or larger than the flow path cross-sectional area of the main passage from the communication site to the opening. .

  If it does so, since it can prevent that the pressure reduction effect in a communicating part is prevented by opening, a residual liquid can be sucked out as designed.

  According to the intake device of the present invention, water and oil accumulated in the lower portion of the chamber can be stably sucked out with a simple configuration.

It is the schematic which shows an example of this kind of conventional intake device. It is the schematic which shows each structure of the intake device and exhaust device which were attached to the engine in this embodiment. It is a schematic perspective view which shows the external appearance of an intake device main body. It is the schematic which shows the external appearance of the intake device main body seen from the upper side. It is the schematic which shows the external appearance of the intake device main body seen from the rear side. It is a schematic sectional drawing seen from the direction shown by the II line in FIG. It is a schematic sectional drawing seen from the direction shown by the II-II line in FIG. It is a schematic sectional drawing which shows the internal structure of the suction passage of the range shown by the virtual line in FIG. It is the schematic seen from the direction shown by the arrow III of the left side in FIG. FIG. 10 is a schematic cross-sectional view as seen from the direction indicated by the line IV-IV in FIG. 9. It is the schematic which shows the front-end | tip part of an air pipe. (A) is the front view seen from the upstream of the flow of intake air, (b) is the side view. It is a figure equivalent to FIG. 11 which shows a modification. It is a figure equivalent to FIG. 11 which shows a reference example . It is the schematic which shows another modification.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the following description is merely illustrative in nature and does not limit the present invention, its application, or its use.

  FIG. 2 shows each configuration of the engine 1 and the intake device 2 and exhaust device 4 attached thereto. The engine 1 is an in-line four-cylinder diesel engine mounted on an automobile, and four cylinders 1a for taking out power by burning a mixture of fuel and intake air are arranged in a row. The fuel supply system is not shown.

  The engine 1 is provided with two intake ports 1b and two exhaust ports 1c for each cylinder 1a. Each intake port 1b is connected to an intake device 2, and intake air is introduced into each cylinder 1a through the intake device 2 and each intake port 1b. Each exhaust port 1c is connected to an exhaust device 4, and exhaust generated in each cylinder 1a is led out through the exhaust device 4 and each exhaust port 1c, and after being subjected to processing such as cleaning, it is discharged into the atmosphere. The

(Outline of intake system)
An air cleaner 10 is disposed at the most upstream portion in the intake passage of the intake device 2 through which intake air flows. The air cleaner 10 removes dust and dirt from the outside air and introduces purified air (intake air) into the intake passage. The downstream side of the air cleaner 10 is connected to the supercharger 11 via the first intake pipe 2a, and the intake air is supercharged by a compressor 11a provided in the supercharger 11.

  The downstream side of the supercharger 11 is connected to the intake device main body 5 via the second intake pipe 2b. Although details will be described later, the intake device body 5 is provided with a chamber 20, an intercooler 40, a valve unit 60 and the like in a compact manner.

  The intercooler 40 is accommodated in the chamber 20 and cools the intake air flowing into the chamber 20. This intercooler 40 is water-cooled, and cooling water is circulated and supplied from the water pump 41 to the intercooler 40 via the cooling pipe 42.

  An intake passage (configured by a vertically long passage 25 and a horizontally long passage 26 described later) on the downstream side of the chamber 20 is directly connected to each intake port 1 b of the engine 1. Accordingly, the intake air cooled by the intercooler 40 and homogenized and equalized in the chamber 20 is immediately introduced into each cylinder 1a.

  An intake passage (a first intake pipe 2a, a second intake pipe 2b, and a connection passage 61 described later) located upstream of the chamber 20 with respect to the flow of intake air constitutes an upstream intake passage, and is downstream of the chamber 20 The intake passage constitutes a downstream intake passage.

(Outline of exhaust system)
The exhaust device 4 is provided with a first exhaust pipe 4a connected to each exhaust port 1c, and the exhaust generated in each cylinder 1a is introduced into the first exhaust pipe 4a. The downstream side of the first exhaust pipe 4 a is connected to the supercharger 11. The turbocharger 11 is provided with a turbine 11b that operates using exhaust gas, and the compressor 11a is driven by the turbine 11b.

  An oxidation catalyst 12 that removes CO and HC in the exhaust gas and a DPF (Diesel Practical Filter) 13 that removes particulate matter in the exhaust gas are arranged in the second exhaust pipe 4b that is connected to the downstream side of the supercharger 11. Has been. The third exhaust pipe 4 c connected to the downstream side of the DPF 13 is connected to the silencer 14. The outlet of the silencer 14 is open to the atmosphere, and the exhaust gas introduced into the exhaust device 4 is discharged from the outlet to the outside.

  The intake device 2 and the exhaust device 4 of the engine 1 are provided with a high pressure EGR device 15, a low pressure EGR device 16, and a blow-by gas recirculation device 17.

  The high-pressure EGR device 15 is a device that introduces high-pressure EGR gas into the intake air. Before the exhaust gas passes through the supercharger 11, the oxidation catalyst 12, and the DPF 13 and is depressurized and cleaned, the high pressure EGR device 15 is connected to the downstream side of the intake passage 2 from the upstream side of the supercharger 11 and the like. The exhaust is recirculated to the high pressure part of

  Specifically, the high pressure EGR device 15 includes a high pressure EGR pipe 15a, a high pressure EGR cooler 15b, a high pressure EGR valve 15c, and the like.

  One end of the high-pressure EGR pipe 15a is connected to the first exhaust pipe 4a, and takes in a part of the exhaust immediately after being led out from each cylinder 1a (high-pressure EGR gas: including carbon). The other end on the downstream side of the high-pressure EGR pipe 15 a is connected to a gas inlet (first gas inlet 27) provided in the intake passage on the downstream side of the intake device body 5.

  The high pressure EGR cooler 15b cools the high pressure EGR gas flowing through the high pressure EGR pipe 15a. The high pressure EGR valve 15c adjusts the flow rate of the high pressure EGR gas flowing through the high pressure EGR pipe 15a. The high pressure EGR gas that has undergone cooling and flow rate adjustment joins the intake air through the first gas inlet 27.

  The low pressure EGR device 16 is a device that introduces low pressure EGR gas into the intake air. After the exhaust gas passes through the supercharger 11, the oxidation catalyst 12, and the DPF 13, and is depressurized and cleaned, the low pressure EGR device 16 starts from the downstream side of the supercharger 11 and the like to the low pressure upstream of the intake passage. Reflux the exhaust to the site.

  Specifically, the low pressure EGR device 16 includes a low pressure EGR pipe 16a, a low pressure EGR cooler 16b, a low pressure EGR valve 16c, and the like.

  One end of the low-pressure EGR pipe 16a is connected to the third exhaust pipe 4c, and a part of the exhaust before being decompressed and cleaned and discharged to the outside (low-pressure EGR gas: compared with high-pressure EGR gas) Less but more water). The other end on the downstream side of the low pressure EGR pipe 16 a is connected to a gas inlet (second gas inlet 18) provided in the first intake pipe 2 a located upstream of the supercharger 11.

  The low pressure EGR cooler 16b cools the low pressure EGR gas flowing through the low pressure EGR pipe 16a. The low pressure EGR valve 16c adjusts the flow rate of the low pressure EGR gas flowing through the low pressure EGR pipe 16a. The low pressure EGR gas that has undergone cooling and flow rate adjustment joins the intake air through the second gas inlet 18.

  The blow-by gas recirculation device 17 is a device that introduces blow-by gas into the intake air. The blow-by gas recirculation device 17 includes a blow-by gas inlet 17a, a blow-by gas inlet 17b (third gas inlet), a blow-by gas pipe 17c, and the like.

  The blow-by gas intake port 17a is installed in, for example, a cylinder head of the engine 1 and is an unburned air-fuel mixture (blow-by gas: containing moisture, oil, and carbon) that flows out from the cylinder 1a when the engine 1 is operated. take in. The blow-by gas introduction port 17b is installed in a low-pressure portion located on the upstream side of the intake passage, specifically, the first intake pipe 2a. The blow-by gas piping 17c is connected to the blow-by gas intake port 17a and the blow-by gas introduction port 17b. The blow-by gas taken in from the blow-by gas intake port 17a merges with the intake air through the blow-by gas pipe 17c and the blow-by gas introduction port 17b.

(Specific configuration of the intake device body)
3 to 7 show the intake device body 5. The intake device body 5 includes a chamber 20, a valve unit 60, an intercooler 40, and the like.

  For convenience, directions such as up, down, left, and right used in the description follow the illustrated arrows unless otherwise specified. Regarding the front-rear direction, the side facing the engine 1 is the rear.

  The chamber 20 is a resin molded product, and as shown in FIGS. 6 and 7, a large-capacity space (internal space 21) for expanding the intake air flow path is formed therein. An inlet 22 connected to the intake passage is formed at the rear of the chamber 20, and the intake air flows into the chamber 20 through the inlet 22. The internal space 21 of the chamber 20 has a channel cross-sectional area (area of a cross section in a direction perpendicular to the flow of intake air) that is larger than that of the inflow port 22, and the intake air flowing into the chamber 20 is in the internal space 21. Diffusion, homogenization and pressure equalization are promoted.

  As shown in FIG. 7, the valve unit 60 is installed near the inflow port 22 and connected to the second intake pipe 2b. The valve unit 60 is rotatably supported in a cylindrical connection passage 61 (which constitutes an upstream intake passage) interposed between the inlet 22 and the second intake pipe 2b, or in the connection passage 61. A disc-shaped valve body 62 (throttle valve), a valve control unit 63 that rotationally drives the valve body 62 and controls its movement are provided. The valve unit 60 adjusts the flow rate of the intake air by changing the opening of the intake passage by controlling the movement of the valve body 62.

  The intercooler 40 is a rectangular parallelepiped structure having a flow path for exchanging heat with intake air, and is accommodated in the internal space 21. The internal space 21 is partitioned by an intercooler 40 into an upstream space 21a through which intake air before cooling flows and a downstream space 21b through which intake air after cooling flows.

  The intercooler 40 is accommodated in the chamber 20 in an inclined state. That is, as shown in FIG. 6, the intercooler 40 is placed inside the chamber 20 in a state where the lower end portion on the upstream space 21 a side of the intercooler 40 is inclined so as to be positioned below the lower end portion on the downstream space 21 b side. is set up.

  Accordingly, the lower end portion of the upstream space 21a is also positioned below the lower end portion of the downstream space 21b, and the lower end portion of the upstream space 21a is the lowest in the internal space 21 of the chamber 20 (chamber 20 Bottom). A flat bottom surface 23 extending in a substantially horizontal direction is formed at the lower portion of the chamber 20.

  There is a tendency that water or oil (collectively referred to as residual liquid) brought in by intake air is accumulated in the lower portion of the lower chamber 20. In particular, if low-pressure EGR gas or blow-by gas is mixed in the intake air, it becomes easier to accumulate.

  An outlet 24 that opens to the upstream space 21 a is formed in the upper part on the front side of the chamber 20, and intake air flows out of the chamber 20 through the inlet 22. The outlet 24 is connected to a longitudinal passage 25 that extends upward while being curved along the upper portion of the chamber 20.

  As shown also in FIG. 4, a horizontally long passage 26 extends separately from the upper end of the vertically long passage 25 in the left and right lateral directions. As shown in FIG. 5, a plurality of port openings 26 a corresponding to the intake ports 1 b of the respective cylinders 1 a are opened in the horizontally long passage 26. By attaching the intake device body 5 to the engine 1, the horizontally long passage 26 is The cylinders 1a communicate with each other through the port openings 26a. The vertically long passage 25 and the horizontally long passage 26 constitute a substantially T-shaped downstream intake passage.

  As shown in FIG. 6, the first gas inlet 27 is formed in the vertically long passage 25, and the high-pressure EGR gas is mixed with the intake air inside the vertically long passage 25.

(Suction passage)
As shown in FIG. 5 and FIG. 6, in order to suck out the residual liquid accumulated in the lower portion of the chamber 20, a thin tube suction passage 7 is provided in the intake device main body 5. The suction passage 7 has a main passage 70 and a sub-passage 80. The main passage 70 bypasses the chamber 20 and communicates with the intake passages on the upstream side and the downstream side of the chamber 20, and the sub passage 80 communicates with the lower portion of the chamber 20 and the main passage 70.

  The sub-passage 80 is formed by welding a tubular member made of resin to the outer surface on the rear side of the chamber 20, and extends in the vertical direction along the outer surface of the chamber 20 as shown in FIG. 6. The lower end of the sub passage 80 communicates with the lower part of the internal space 21. Specifically, the sub-passage 80 has a suction port 81 that opens to the lower end portion of the upstream space 21a and has the lower end positioned at a height equal to or lower than that of the bottom surface 23. The upper end of the sub passage 80 is connected to the main passage 70 at a communication portion 90 located at the same height as the upper portion of the internal space 21.

  The main passage 70 includes an air pipe 71 (intake air introduction portion) of a resin molded product, a rubber hose 72, an aspirator 73 having a substantially T shape, an internal passage 74, and the like. An intermediate portion of the main passage 70 is disposed along the outer surface on the rear side of the chamber 20 so as to extend in the left-right lateral direction at the same height as the upper portion of the internal space 21 (straight line portion). An aspirator 73 is disposed in the straight line portion, and the aspirator 73 constitutes a communication part 90.

  The aspirator 73 is configured using a resin tubular member, and is formed integrally with the chamber 20 by welding to the outer surface of the rear side of the chamber 20. As shown in FIG. 8, the aspirator 73 has a main flow portion 73 a that forms a linear flow channel extending in a straight line, and a tubular shape that branches from an intermediate portion of the main flow portion 73 a and extends in a direction perpendicular to the main flow portion 73 a. And a suction part 73b that forms a flow path. The sub passage 80 communicates with the main passage 70 through the suction portion 73b.

  The left end portion of the main flow portion 73a is formed in a tube shape having an open front end, and is inserted into the hose 72 and fastened and fixed. At the right end of the main flow portion 73a, a sealing portion 73c that seals the opening at the right end of the tubular flow path with a stopper and a curved end portion 73d that branches from the sealing portion 73c and curves upward are formed. Has been.

  As shown in FIG. 6, the internal passage 74 is formed so as to extend a portion between the upper portion of the chamber 20 and the longitudinal passage 25 in the intake device main body 5. One end on the upstream side of the internal passage 74 is connected to the curved end 73 d on the outer surface of the chamber 20. The internal passage 74 communicates with the longitudinal passage 25 at one end on the downstream side.

  Specifically, as shown in FIG. 4, on the downstream side of the vertically long passage 25 (in the vicinity of the portion connected to the horizontally long passage 26), the two inner walls (downstream connecting portions) on the chamber 20 side are opposed to each other in the left-right direction. A small liquid inlet 75 is formed. The downstream side of the internal passage 74 communicates with the longitudinal passage 25 through these liquid inlets 75.

  In the present embodiment, the first gas inlet 27 for introducing the high-pressure EGR gas is formed at a site upstream of the longitudinal passage 25. That is, it is configured to be located upstream from the downstream connection site.

  An aspirator structure AS in which the flow path is narrowed (the cross-sectional area of the flow path is reduced) is formed in a T-shaped joining portion where the main passage 70 and the sub-passage 80 communicate with each other so that a reduced pressure state is formed by the venturi effect. Is provided.

  Therefore, when the intake air flows through the main flow portion 73 a, the internal pressure of the merged portion is reduced, and a suction force is generated that is sucked through the sub-passage 80 from the suction port 81 located in the lower portion of the inner space 21 of the chamber 20. As a result, even if the residual liquid accumulates in the lower part of the chamber 20, the residual liquid can be effectively sucked up to the upper part of the chamber 20.

(Air pipe: intake air inlet)
As shown in FIGS. 9 and 10, the air pipe 71 is attached to the valve unit 60, and an aspirator 73 is connected to a cylindrical base end portion 71 a of the air pipe 71 protruding to the outside of the valve unit 60. The other end of the hose 72 is fastened and fixed.

  The valve unit 60 is formed with an insertion hole 64 communicating with the connection passage 61, and an air pipe 71 is inserted into the insertion hole 64 and fixed in an airtight state. A portion where the air pipe 71 is fixed (upstream connection portion) is located upstream of the valve body 62.

  The front end portion of the air pipe 71 protrudes from the inner wall surface 61a of the connection passage 61 toward the center of the connection passage 61, and an opening 71b for introducing the intake air to the hose 72 through the tubular passage 71e is formed at the front end. And this opening 71b is arrange | positioned so that it may be located away from the inner wall face 61a to the center side of the connection channel | path 61 while heading upstream.

  By doing so, intake air can be efficiently taken into the opening 71b by the dynamic pressure, and even if oil flows along the inner wall surface 61a of the connection passage 61, the oil is effectively suppressed from flowing into the opening 71b. can do.

  As shown also in FIG. 11, in this embodiment, the front-end | tip part of the air pipe 71 is formed in the cylindrical shape, and the front-end | tip surface is inclined so that it cut | disconnected diagonally. Thereby, an elliptical opening 71 b is formed on the tip end side of the air pipe 71.

  The opening 71b is disposed toward the upstream side of the intake air flow. The opening 71b preferably faces the intake air flow, but does not necessarily face it. That the opening 71b faces the upstream side means that at least a part of the opening 71b only needs to face the direction in which the intake air flows. In short, the intake air may be taken into the opening 71b by dynamic pressure.

  In particular, in the present embodiment, the opening 71b is inclined so as to gradually move away from the inner wall surface 61a from the upstream side toward the downstream side. Specifically, as shown in FIG. 11, with respect to the direction of intake air flow, the end of the opening 71b located on the downstream side is defined as the downstream end 71bd, and the end of the opening 71b located on the upstream side is defined as the upstream. In the case of the side end portion 71bu, the downstream end portion 71bd is located farther from the inner wall surface 61a than the upstream end portion 71bu and positioned on the center side of the connecting passage 61. By doing so, even if the opening 71b is opposed to the flow of intake air, the flow of intake air can be prevented from being greatly disturbed.

  The opening 71b is disposed so as to be separated from the inner wall surface 61a toward the center of the connecting passage 61. Specifically, as shown in FIG. 11, the end of the opening 71b positioned closest to the inner wall surface 61a (in the present embodiment, the upstream end 71bu) is located at a distance h from the inner wall surface 61a. Yes.

  Therefore, since the opening 71b is located on the center side of the connecting passage 61 where the flow of intake air is relatively strong, intake air can be taken in more efficiently.

  With such a configuration, even if the pressure difference between the upstream side of the valve body 62 and the downstream side of the intake passage is small, intake air can be efficiently guided to the suction passage 7 by the dynamic pressure. Therefore, even in the diesel engine 1 in which the valve body 62 is often fully opened during the operation period, the intake air can be always stably guided to the suction passage 7 and the residual liquid is accumulated in the lower portion of the chamber 20. Can be prevented.

  Moreover, since the aspirator structure AS is provided in the middle of the suction passage 7 and the negative pressure generated there is used to suck from the lower portion of the chamber 20, even if the amount of intake air flowing through the suction passage 7 is small, You can inhale efficiently.

  By arranging the joining portion of the main passage 70 and the sub-passage 80 in the upper part of the chamber 20, it is possible to effectively suppress the back flow of the residual liquid while having a simple structure.

  In particular, the opening 71b is designed so that the suction by the aspirator 73 can be performed efficiently.

  That is, the reduced pressure state formed by the aspirator 73 is affected by the size of the tubular flow path through which the intake air flows. In particular, the flow path cross section (the minimum flow path cross section if not constant) of the portion (introduction site) from the opening 71b to the communication site 90 in the main passage 70 is important.

  On the other hand, if the effective area of the opening 71b is smaller than that of the flow path cross section, the required pressure reducing effect cannot be obtained, and therefore the effective area of the opening 71b is formed to be larger than the flow path cross section of the introduction site. Specifically, as shown in FIG. 11A, the area of the projected view of the opening 71b viewed from the direction in which the intake air flows (effective area: the area of the portion indicated by the dot) is the flow path cross-sectional area of the introduction site. It is formed in the above size.

  However, the larger the effective area of the opening 71b, the more obstructed the flow of intake air. Therefore, it is preferable that the effective area of the opening 71b is substantially the same as the cross-sectional area of the flow path.

  In addition, by arranging the opening 71b away from the inner wall surface 61a, oil flowing along the inner wall surface 61a of the connecting passage 61 can be effectively suppressed from flowing into the opening 71b.

  When blow-by gas is introduced into the intake air, oil is mixed into the intake air. Most of the oil mixed in the intake air is pushed downstream along the inner wall surface 61a of the intake passage. For this reason, if the opening 71b is arranged on the inner wall surface 61a, oil may flow into the opening 71b and cause problems in the suction passage 7. However, if the opening 71b is arranged away from the inner wall surface 61a, the opening 71b is moved to the opening 71b. Inflow of oil can be effectively prevented.

  Further, the air pipe 71 is provided with a weir portion 71c that blocks oil from flowing into the opening 71b. Specifically, as shown in FIG. 11, an annular ring groove 71c1 is formed around the opening 71b so as to be gradually separated from the inner wall surface 61a from the upstream side toward the downstream side. The ring groove 71c1 makes it easy for oil flowing toward the opening 71b along the air pipe 71 to flow downstream along the ring groove 71c1, and to prevent inflow into the opening 71b.

  Further, an arcuate or annular protrusion 71c2 is formed between the opening 71b and the ring groove 71c so as to surround at least the edge of the upstream end 71bu. Since the protrusion 71c2 can effectively prevent the inflow of oil from the portion where the oil is most likely to flow, the inflow to the opening 71b can be further prevented.

  Thus, the arrangement of the opening 71b and the form of the air pipe 71 have been devised, so that the inflow of oil into the opening 71b can be prevented more effectively.

  In the present embodiment, most of the narrow tubular suction passage 7 is provided on the outer surface of the chamber 20, and thus tends to freeze. However, since heat can be efficiently absorbed from the chamber 20, It can be easily melted even during the start-up.

  Since the low-pressure EGR gas has a lower temperature and a lower pressure than the high-pressure EGR gas, it usually contains a lot of moisture. When this low-pressure EGR gas is mixed with intake air upstream of the chamber 20, residual liquid tends to accumulate inside the chamber 20.

  On the other hand, in this intake device, since the residual liquid can be sucked out stably at all times, even if the low pressure EGR gas is introduced into the intake air, it is effective that a large amount of the residual liquid is accumulated in the lower portion of the chamber 20. Can be suppressed.

  Cooling the intake air with the intercooler 40 facilitates the generation of residual liquid on the downstream side. However, by accommodating the intercooler 40 in the chamber 20, the residual liquid is collected in the lower part of the chamber 20 and efficiently from the intake passage. Can be eliminated. This is also advantageous for making the device compact.

  Since the high-pressure EGR gas contains carbon, there is a possibility that carbon adheres to and accumulates on the inner wall of the intake passage on the downstream side. In particular, the small liquid introduction port 75 may cause clogging due to adhesion of carbon. However, since the intake air and the residual liquid are constantly ejected stably from the liquid introduction port 75, the carbon adheres to the liquid introduction port 75. Etc. can be effectively suppressed, and the residual liquid can be sucked out stably.

(Modifications, etc.)
The intake device according to the present invention is not limited to the above-described embodiment, and includes various other configurations.

  The form of the intake air inlet is an example, and can be changed as appropriate according to the specifications.

  For example, as shown in FIG. 12, the tip of the air pipe 71 is formed in a cylindrical shape having a circular opening 71b at the tip, and the air pipe 71 is connected to the valve unit 60 so that the tip side is inclined toward the upstream side. You may arrange. In this modification, the weir portion 71c is configured by an annular groove 71c1 'formed along the outer peripheral surface of the air pipe 71.

Similarly, as shown in FIG. 13 (reference example) , the distal end portion of the air pipe 71 is bent into an L shape, and a bent base portion that projects radially from the inner wall surface 61a of the connection passage 61 to the distal end portion of the air pipe 71; A bent tip portion that extends perpendicularly to the bent base portion may be formed, and the opening 71b at the tip of the bent tip portion may be disposed in the state facing the upstream side. In this case, the connecting portion between the bent base and the bent tip can function as a weir.

  Further, as shown in FIG. 14, the dam portion 71c may be formed in a flange shape that projects from the periphery of the opening 71b.

  The intercooler is not necessarily accommodated in the chamber, and may be installed separately from the chamber. The intercooler, the high pressure EGR device, the low pressure EGR device, and the blow-by gas recirculation device are not essential and may not be provided in the intake device.

1 Engine 1a Cylinder 2 Intake device 2a First intake pipe (upstream intake passage)
2b Second intake pipe (upstream intake passage)
5 Intake device body 7 Suction passage 11 Supercharger 15 High-pressure EGR device 16 Low-pressure EGR device 17 Blow-by gas recirculation device 17b Blow-by gas inlet (third gas inlet)
18 Second gas introduction port 20 Chamber 22 Inlet 24 Outlet 25 Vertical passage (downstream intake passage)
26 Horizontal passage (downstream intake passage)
27 First gas introduction port 40 Intercooler 60 Valve unit 61 Connecting passage (upstream intake passage)
61a Inner wall surface 62 Valve element (throttle valve)
70 Main passage 71 Air pipe (intake air inlet)
71b Opening 71bd Downstream end portion 71bu Upstream end portion 71c Weir portion 71c1 Ring groove 71c2 Protrusion 80 Sub-passage 90 Communication site

Claims (8)

An intake device that introduces intake air into a cylinder of an engine,
A chamber having an inflow port through which intake air flows, and having a cross-sectional area larger than that of the inflow port;
An upstream intake passage that is connected to the inlet and guides intake air to the inlet;
A downstream side intake passage connected to the outlet of the chamber and guiding intake air to the cylinder;
A throttle valve arranged in the upstream intake passage and changing the opening of the flow path;
A tubular suction passage for sucking out residual liquid accumulated in the lower portion of the chamber;
With
The suction passage is
A main passage that bypasses the chamber and communicates with an upstream connection portion located upstream of the throttle valve in the upstream intake passage and a downstream connection portion located in the downstream intake passage;
A sub-passage communicating with the lower portion of the chamber and the main passage;
Have
The main passage has an intake introduction portion that protrudes from an inner wall surface of the upstream intake passage at the upstream connection portion and has an opening for introducing intake air.
The opening is located on the upstream side and away from the inner wall surface to the center side of the upstream intake passage ,
When the downstream end of the opening located on the downstream side and the upstream end located on the upstream side are viewed with respect to the direction in which the intake air flows, the downstream end is more than the upstream end. An air intake device located on the center side of the upstream intake passage from the inner wall surface. The intake device according to claim 1 ,
The air intake apparatus in which the weir part which interrupts | blocks the inflow of the oil to the said opening is provided in the said air intake introduction part. In the inhalation device according to claim 1 or 2 ,
An air intake apparatus in which a first gas introduction port for introducing high-pressure EGR gas is provided in a portion upstream of the downstream connection portion in the downstream intake passage. In the inhalation device according to any one of claims 1 to 3 ,
A supercharger is disposed at a location upstream of the throttle valve in the upstream intake passage,
An intake system in which a second gas introduction port for introducing low-pressure EGR gas is provided in a portion upstream of the supercharger in the upstream intake passage. In the intake device according to any one of claims 1 to 4 ,
An air intake apparatus in which a third gas introduction port for introducing blow-by gas is provided in a portion upstream of the upstream connection portion in the upstream intake passage. In the intake device according to any one of claims 1 to 5 ,
An air intake device in which an intercooler for cooling intake air is accommodated in the chamber. In the inhalation device according to any one of claims 1 to 6 ,
The auxiliary passage communicates with the main passage at a communication portion positioned higher than the lower portion of the chamber,
An air intake device in which an aspirator structure that forms a decompressed state in the communication part by using intake air flowing through the main passage is provided in the communication part. The intake device according to claim 7 ,
An air intake apparatus in which an area of a projected view of the opening viewed from a direction in which the intake air flows has a size greater than or equal to a flow path cross-sectional area of a portion from the communication portion to the opening in the main passage.

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