JP2019132260A - Intake system of internal combustion engine - Google Patents

Abstract

To provide an intake system of an internal combustion engine which can inhibit foreign objects flowing from an air cleaner to the downstream side from entering into an airflow sensor.SOLUTION: An intake system 100 of an internal combustion engine 1 includes: an intake pipe 10 extending from an air cleaner 2 to the downstream side; an inner cylinder 20 arranged coaxially with the intake pipe 10; an airflow sensor 30 having an intake air introduction port 30in in the inner cylinder 20; and a swirling part 40 which is provided at the intake pipe 10 located between an outlet 2out of the air cleaner 2 and an inlet 20in of the inner cylinder 20 and generates swirl flow around an axis C of the intake pipe 10.SELECTED DRAWING: Figure 2

Description

  The present disclosure relates to an intake device for an internal combustion engine mainly including an intake pipe and an air flow sensor.

  Generally, an intake device for an internal combustion engine includes an intake pipe that extends downstream from an air cleaner, and an airflow sensor that is provided in the intake pipe and has an intake inlet in the intake pipe.

Japanese Patent Application Laid-Open No. 2015-072003

  In the above intake device, fine foreign matter (for example, dust or moisture) that has flowed downstream from the air cleaner may enter the air flow sensor from the intake inlet. In this case, there is a possibility that the invading foreign matter adheres to the sensing unit and the output of the air flow sensor changes.

  Accordingly, the present disclosure has been made in view of such circumstances, and an object of the present disclosure is to provide an intake device for an internal combustion engine that can prevent foreign matters flowing downstream from an air cleaner from entering the air flow sensor.

  An intake device for an internal combustion engine according to the present disclosure includes an intake pipe that extends downstream from an air cleaner, an inner cylinder that is coaxially disposed in the intake pipe, an intake pipe that is provided in the intake pipe, and an intake inlet that is provided in the inner cylinder. And an air flow sensor provided in the intake pipe positioned between the outlet of the air cleaner and the inlet of the inner cylinder, and a swirling portion that generates a swirling flow around the axis of the intake pipe.

  Moreover, it is preferable that a rectification part is provided in the inner cylinder on the upstream side of the intake inlet.

  The intake pipe is preferably provided with a collecting portion for collecting the foreign matter urged radially outward by the swirling flow.

  Moreover, it is preferable that the said collection part is provided with the one valve which opens when the internal pressure of the said intake pipe is higher than atmospheric pressure, and discharges | emits the collected said foreign material to the outer side of the said intake pipe.

  Further, it is preferable that a recirculation passage for recirculating the blow-by gas is connected to the intake pipe, and the collecting unit stores oil contained in the blow-by gas recirculated to the intake pipe.

  According to the intake device for an internal combustion engine according to the present disclosure, it is possible to prevent foreign matters that have flowed downstream from the air cleaner from entering the air flow sensor.

1 is a schematic configuration diagram of an entire internal combustion engine including an intake device according to a first embodiment. It is a schematic block diagram of the intake device and air cleaner shown in FIG. FIG. 3 is an enlarged cross-sectional view of the intake device shown in FIG. 2. It is IV-IV sectional drawing of FIG. It is VV sectional drawing of FIG. It is a schematic block diagram of the intake device and air cleaner which concern on 2nd Embodiment. It is an expanded sectional view of the air intake device shown in FIG. It is VIII-VIII sectional drawing of FIG. It is a schematic block diagram of the intake device and air cleaner which concern on 3rd Embodiment. FIG. 10 is an enlarged cross-sectional view of the intake device shown in FIG. 9. It is XI-XI sectional drawing of FIG. It is a schematic block diagram of the intake device and air cleaner which concern on a 1st modification. It is XIII-XIII sectional drawing of FIG. It is a schematic block diagram of the intake device which concerns on a 2nd modification. It is a schematic block diagram of the intake device and air cleaner which concern on a 2nd modification. It is XVI-XVI sectional drawing of FIG. It is a figure which shows the other modification of FIG.

  Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings.

(First embodiment)
FIG. 1 is a schematic configuration diagram of an entire internal combustion engine 1 including an intake device 100 according to the first embodiment. 2 is a schematic configuration diagram of the intake device 100 and the air cleaner 2 shown in FIG. 1, and FIG. 3 is an enlarged cross-sectional view of the intake device 100 shown in FIG. 4 is a cross-sectional view taken along the line IV-IV in FIG. 3, and FIG. 5 is a cross-sectional view taken along the line V-V in FIG. In the figure, an open arrow A indicates the flow of intake air. Reference sign B indicates a foreign matter (for example, fine dust or mist-like moisture), and reference sign C indicates a tube axis of the intake pipe 10.

  As shown in FIGS. 1 and 2, the intake device 100 of the internal combustion engine 1 includes an intake pipe 10 that extends downstream from the air cleaner 2 and an inner cylinder 20 that is coaxially disposed in the intake pipe 10. The intake device 100 includes an air flow sensor 30 provided in the intake pipe 10 and having an intake inlet 30in in the inner cylinder 20. The intake device 100 includes a fin 40 that is provided in the intake pipe 10 positioned between the outlet 2out of the air cleaner 2 and the inlet 20in of the inner cylinder 20 and generates a swirling flow around the axis C of the intake pipe 10. . In the present embodiment, the fin 40 corresponds to the swivel unit of the present disclosure.

  As shown in FIG. 1, the internal combustion engine 1 is a multi-cylinder compression ignition internal combustion engine mounted on a vehicle (not shown), that is, a diesel engine. However, the use and type of the internal combustion engine 1 may be arbitrary.

  The internal combustion engine 1 includes a cylinder block 3, a cylinder head 4 connected to the upper part of the cylinder block 3, and a crankcase 5 formed at the lower part of the cylinder block 3.

  An intake pipe 10 is connected to the cylinder head 4 via an intake manifold 6 and a turbocharger compressor 7. However, the turbocharger may not be provided.

  A gas hose 8 that recirculates blow-by gas is connected to the intake pipe 10. The gas hose 8 constitutes a part of a return passage for returning the blow-by gas in the crankcase 5 to the intake pipe 10. The gas hose 8 is connected to an intake pipe 10 on the upstream side of the compressor 7.

  As shown in FIG. 2, an outlet 2 out of the air cleaner 2 is connected to the inlet 10 in of the intake pipe 10. The intake pipe 10 is formed to extend in the horizontal direction from the inlet 10 in to at least the position of the downstream end of the inner cylinder 20. However, the intake pipe 10 of the present embodiment may have any shape and angle, and may extend from the inlet 10in of the intake pipe 10 in the vertical direction, for example.

  The air cleaner 2 includes a cylindrical filter element 2a. However, the filter element 2a may be of any type.

  An outlet 9out of an intake duct 9 having an intake port (not shown) is connected to the inlet 2in of the air cleaner 2.

  As shown in FIG. 3, the air cleaner 2 is configured to filter and collect the foreign matter B in the intake air with the filter element 2a, but a small amount of fine foreign matter B passes through the filter element 2a and is downstream. To leak. However, the air cleaner 2 is set to a collection efficiency that does not affect the durability of the internal combustion engine 1 even if the foreign matter B is sucked into each cylinder (not shown).

  The intake pipe 10 disposed on the radially outer side of the inner cylinder 20 has an insertion hole 11 for attaching the airflow sensor 30 to the outer peripheral portion (illustrated, upper surface portion).

  A cylindrical tube member is applied to the inner cylinder 20, and an inlet 20in and an outlet 20out are formed. The inner cylinder 20 is disposed coaxially with the pipe axis C of the intake pipe 10. Here, “coaxial” means a state that is coaxial or slightly non-coaxial to the extent that the flow of intake air is not hindered, for example, a state that is inclined and offset with respect to the tube axis C. The inner cylinder 20 of the present embodiment is disposed coaxially with the tube axis C. The cross-sectional shape of the inner cylinder 20 may be arbitrary. For example, the inner cylinder 20 may not have a constant cross-sectional shape from the inlet 20in to the outlet 20out, and may have a shape in which the whole or a part (the vicinity of the inlet 20in, etc.) is enlarged or reduced in a tapered shape. .

  Further, the inner cylinder 20 has an insertion hole 21 for attaching the airflow sensor 30 to an outer peripheral portion (illustrated, upper surface portion) located between the inlet 20in and the outlet 20out. The insertion hole 21 is provided coaxially with the insertion hole 11 formed in the upper surface portion of the intake pipe 10. A cylindrical member T1 extending in the radial direction of the intake pipe 10 (the vertical direction in the drawing) is provided in contact with the inner peripheral surfaces of the insertion holes 11 and 21. The cylinder member T <b> 1 is arranged from the insertion hole 11 of the intake pipe 10 to the position of the insertion hole 21 of the inner cylinder 20.

  A rectifying plate 22 as a rectifying unit is provided at the inlet 20 in of the inner cylinder 20. The current plate 22 is formed in a lattice shape or a honeycomb shape, and is fixed to the inner wall portion 23 of the inlet 20 in of the inner cylinder 20. However, the rectifying plate 22 may be provided at a position downstream of the inlet 20in as long as it is in the inner cylinder 20 upstream of the intake inlet 30in of the airflow sensor 30. Further, the type and shape of the rectifying unit may be arbitrary.

  The inner cylinder 20 of the present embodiment is supported by a plurality of rod-like support members 50 extending radially inward from the inner wall portion 12 of the intake pipe 10 (see FIG. 5). It is provided so that intake air flows through the gap. The shape, position, number, etc. of the support member 50 may be arbitrary.

  A hot-wire airflow sensor is applied to the airflow sensor 30. Specifically, the airflow sensor 30 has a case 31 that is inserted into the insertion holes 11 and 21 via the cylindrical member T <b> 1 and is disposed in the inner cylinder 20. The airflow sensor 30 has a hot wire 32 as a sensing unit housed in the case 31.

  Although not shown, the air flow sensor 30 is configured to output the intake air temperature sensed by the hot wire 32 to an electronic control unit or controller, and to detect the intake air flow rate based on a change in the intake air temperature.

  The case 31 has an intake inlet 30in on the upstream end face, and an intake exhaust outlet 30out on the downstream end face. The intake inlet 30in and the intake outlet 30out are coaxially opened in the inner cylinder 20.

  In the case 31, the hot wire 32 is provided in the middle of the flow path from the intake inlet 30in to the intake outlet 30out. In the present embodiment, the hot wire 32 formed of platinum or the like is used as the sensing unit. However, any thermal element formed of silicon or the like may be used as the sensing unit.

  As shown in FIGS. 3 and 4, the fin 40 has a plurality (four in the illustrated example) of blade members or plate members and extends radially from the position of the tube axis C to the inner wall portion 12 of the intake pipe 10. Fixed.

  More specifically, the fin 40 is configured to be inclined in the circumferential direction by being inclined with respect to the axial direction in the intake pipe 10 from the upstream side toward the downstream side. Further, the fin 40 is configured to urge the foreign matter B that has flowed downstream from the air cleaner 2 to the radially outer side than the inner cylinder 20 by the swirled intake air. However, the type and shape of the fin 40 may be arbitrary.

  Further, the fin 40 is arranged at a position immediately before the inner cylinder 20. In the illustrated example, the fin 40 is disposed at a position immediately after the air cleaner 2, but the position of the fin 40 may be an arbitrary position in the intake pipe 10.

  Next, the effect of the intake device 100 according to the first embodiment will be described.

  As shown in FIGS. 1 to 3, in the air cleaner 2, most foreign matter B (for example, dust) in the intake air is filtered out by the air filter 2 a, but a small amount of fine foreign matter B passes through the air filter 2 a. It slips and flows downstream. Further, for example, when water adheres to the air filter 2a during traveling in the rain, mist-like moisture may flow out downstream as the foreign matter B.

  Here, although not shown in the drawings, in the intake device of the comparative example that does not include the inner cylinder 20 and the fins 40 of the present embodiment, foreign matter that flows out downstream from the air cleaner may enter the inside from the intake inlet of the air flow sensor. is there. In this case, there is a possibility that the invading foreign matter adheres to the hot wire and changes the output of the air flow sensor.

  In particular, when the dust attached to the hot wire increases due to long-term use, the air flow sensor may be deteriorated such that output change increases and detection accuracy decreases.

  On the other hand, in the intake device 100 of the present embodiment, as shown by the white arrow A, the swirl flow is generated by the fins 40 so that the foreign matter B that has flowed downstream from the air cleaner 2 is transferred from the inner cylinder 20. Is also urged radially outward. Then, the foreign matter B urged radially outward passes through the gap between the intake pipe 10 and the inner cylinder 20 and flows downstream. Thereby, it can suppress that the foreign material B penetrate | invades in the inner cylinder 20, and also can penetrate | invade into the airflow sensor 30 from the intake inlet 30in. As a result, the foreign matter B can be prevented from adhering to the hot wire 32, and the output change of the air flow sensor 30 can be suppressed. And even when the airflow sensor 30 is used for a long period of time, deterioration of detection accuracy can be suppressed and deterioration can be suppressed.

  In the present embodiment, the rectifying plate 22 is provided in the inner cylinder 20 on the upstream side from the intake inlet 30in. Thereby, the swirling flow generated in the fin 40 can be eliminated or attenuated. As a result, the intake air having no swirl component can be introduced into the airflow sensor 30 to improve the detection accuracy of the airflow sensor 30.

(Second Embodiment)
FIG. 6 is a schematic configuration diagram of the intake device 200 and the air cleaner 2 according to the second embodiment, and FIG. 7 is an enlarged cross-sectional view of the intake device 200 shown in FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. Note that the intake device 200 according to the second embodiment is obtained by adding a collection unit 60 to the intake device 100 according to the first embodiment, and the other components are the same as those of the first embodiment, and thus the same components The same reference numerals are used for, and detailed descriptions thereof are omitted.

  As shown in FIG. 6, the intake pipe 10 of the second embodiment is provided with a collection unit 60 for collecting the foreign matter B urged radially outward by the swirling flow.

  Specifically, as shown in FIGS. 7 and 8, the collection unit 60 of the present embodiment opens when the internal pressure of the intake pipe 10 is higher than the atmospheric pressure, and sucks the collected foreign matter B. A one-way valve 61 that discharges into the atmosphere outside the tube 10 is provided.

  The collection unit 60 has a tubular opening 13 provided at the lower end of the intake pipe 10. The opening 13 is located on the radially outer side of the upstream end of the inner cylinder 20. However, the position and shape of the opening 13 may be arbitrary. For example, the opening 13 may be positioned on the radially outer side of the downstream end of the inner cylinder 20.

  On the other hand, the valve 61 is formed in a cap shape by rubber or a resin material, and has a slit 61a at the tip. On the other hand, the valve 61 is fitted and attached to the opening 13 from below, and constitutes a concave collection part 60 together with the opening 13. However, the structure of the one-way valve 61 may be arbitrary. Further, the one-way valve 61 may be formed integrally with the opening 13.

  On the other hand, a reverse flow suppressing member 62 (for example, a net member) is provided in the opening 13 to allow the foreign matter B to pass from the intake pipe 10 to the slit 61a side and to prevent reverse flow in the opposite direction. However, the backflow suppressing member 62 may not be provided.

  Next, the effect of the intake device 200 according to the second embodiment will be described.

  According to the second embodiment, the foreign matter B urged radially outward from the inner cylinder 20 by the swirling flow can be collected by the collection unit 60.

  In addition, since the opening 13 of the collecting part 60 is positioned on the radially outer side of the upstream end of the inner cylinder 20, the foreign matter B can be efficiently collected by the strong swirling flow that flows near the fins 40.

  The collected foreign matter B can be discharged into the atmosphere by opening the one-way valve 61 when the internal pressure of the intake pipe 10 is higher than atmospheric pressure.

  Further, the collected foreign matter B can be prevented from flowing back into the intake pipe 10 by the backflow suppressing member 62 even when the internal pressure of the intake pipe 10 is lower than the atmospheric pressure.

(Third embodiment)
FIG. 9 is a schematic configuration diagram of the intake device 300 and the air cleaner 2 according to the third embodiment, and FIG. 10 is an enlarged cross-sectional view of the intake device 300 shown in FIG. 11 is a cross-sectional view taken along the line XI-XI in FIG. In addition, in 3rd Embodiment, although the structure of a collection part differs from 2nd Embodiment, since the other part is the same as 2nd Embodiment, it uses the same code | symbol for the same component, and those detailed description Is omitted.

  As shown in FIGS. 9-11, the collection part 70 of 3rd Embodiment is comprised so that the oil contained in not only the foreign material B but the blowby gas recirculated | refluxed to the intake pipe 10 may be collected.

  The collection unit 70 is formed by a recess in which the inner wall 12 (illustrated, lower end) of the intake pipe 10 is recessed downward. However, the collection unit 70 may be formed separately from the intake pipe 10.

  More specifically, as shown in FIG. 1, in the intake pipe 10, when the connection portion with the gas hose 8 is located at a higher position than the inner cylinder 20, the gas hose 8 is attached around the connection portion. The oil O tends to flow and move upstream of the intake pipe 10 when the internal combustion engine 1 is stopped. As shown in FIGS. 10 and 11, the collection unit 70 is configured to store the oil O that has flowed upstream.

  The collection unit 70 is formed in a gently curved concave shape, and is configured so that the stored oil O is sent to the downstream side by intake air when the internal combustion engine 1 is restarted.

  Further, the collection unit 70 is formed in the intake pipe 10 that is located on the radially outer side of the upstream end portion of the inner cylinder 20. However, the position of the collection part 70 may be arbitrary.

  According to the third embodiment, the foreign substance B (particularly dust) urged radially outward can be adsorbed and collected by the oil O stored in the collecting unit 70. Moreover, since the collection part 70 is located in the radial direction outer side of the upstream edge part of the inner cylinder 20, it can collect the foreign material B efficiently by the strong swirl flow which flows near the fin 40.

  In the third embodiment, when the internal combustion engine 1 is restarted after being stopped, the foreign matter B adsorbed by the oil O in the collection unit 70 is sucked by the intake air passing through the gap between the intake pipe 10 and the inner cylinder 20. Since the oil O is sent downstream together with the oil O, it is possible to suppress the dust from rolling up. As a result, the foreign matter B can be effectively prevented from entering the intake inlet 30in.

  Note that the present disclosure is not limited to the above-described embodiment, and can be implemented with appropriate modifications within a scope not departing from the gist of the present disclosure.

  For example, the air flow sensor 20 may be of any type (hot film type, Karman vortex type, etc.) instead of the hot wire type using the hot wire 32.

  Moreover, each above-mentioned embodiment can be deform | transformed as follows. In the following description, the same reference numerals are used for the same components as those in the above embodiments, and detailed descriptions thereof are omitted.

(First modification)
FIG. 12 is a schematic configuration diagram of the intake device 300 and the air cleaner 2 according to the first modification, and FIG. 13 is a cross-sectional view taken along the line XIII-XIII of FIG.

  In each of the embodiments described above, the fin 40 provided in the intake pipe 10 is used as the swivel unit. On the other hand, as shown in FIGS. 12 and 13, the swivel portion of this modification is formed by a scroll-shaped tube member 80 provided integrally or separately at the upstream end of the intake pipe 10. Has been.

  According to the pipe member 80, a swirling flow is generated in the intake pipe 10, and the same effect as the fin 40 in each of the above-described embodiments can be obtained.

(Second modification)
FIG. 14 is a schematic configuration diagram of an intake device 500 according to the second modification. FIG. 15 is a schematic configuration diagram of the intake device 500 and the air cleaner 2 according to the second modification, and FIG. 16 is a cross-sectional view taken along the line XVI-XVI of FIG.

  As shown in FIG. 14, the support member 90 of the second modification may be formed in a blade shape or a plate shape. More specifically, the support member 90 of the second modified example is inclined with respect to the axial direction as it goes from the upstream side to the downstream side, so that the swirl flow generated in the fins 40 flows smoothly downstream without being obstructed. It may be configured. Although not shown, the fin 40 and the inclined support member 90 may have a continuous and integral shape.

  As shown in FIGS. 14 to 16, the tubular member T <b> 2 of this modification has a streamlined cross-sectional shape parallel to the direction of the swirl flow so as not to disturb the swirl flow as much as possible. Also good. However, the cylindrical member T2 may have an arbitrary shape. For example, a streamlined cross-sectional shape parallel to the tube axis C of the intake pipe 10 may be used as in a cylindrical member T3 shown in FIG.

  Further, the inner cylinder 20 of the present modification may be provided with a communication hole 24 that communicates the inner side and the outer side of the inner cylinder 20 at a position downstream of the rectifying plate 22 and upstream of the intake inlet 30in. good. In the illustrated example, a plurality of communication holes 24 are formed in the circumferential direction of the inner cylinder 20, but the number of holes may be single. Further, the position of the communication hole 24 may be upstream of the rectifying plate 22.

  In this modification, it is possible to suppress the intake air flowing while being inclined with respect to the tube axis C from being inhibited by the support member 90 and the cylindrical member T2, and to smoothly flow the intake air downstream.

  Even when the pressure difference between the outside and the inside of the inner cylinder 20 is large and the flow of intake air inside the inner cylinder 20 is not stable, the pressure difference can be reduced by providing the communication hole 24 in the inner cylinder 20.

(Third Modification)
Although not shown, the collection part may be provided in the intake pipe. For example, the collection part may be a sponge-like adsorption member laid on the inner wall part of the intake pipe. If it is such a collection part, the foreign material urged | biased by the swirl flow to the radial direction outer side from the inner cylinder can be adsorbed and collected.

  In particular, by providing the suction member of this modification instead of the trapping portion 70 of the third embodiment shown in FIGS. 9 to 11, the foreign matter B is adsorbed and collected by the suction member containing the oil O. The Further, since the foreign matter B is sent downstream together with the oil O by intake air, it is possible to suppress the dust from being rolled up.

1 Internal combustion engine 2 Air cleaner 8 Gas hose (recirculation passage)
DESCRIPTION OF SYMBOLS 10 Intake pipe 12 Inner wall part 20 Inner cylinder 22 Rectifier plate (rectifier part)
30 Airflow sensor 30 in Inlet inlet 30 out Inlet outlet 31 Case 32 Hot wire 40 Fin (swivel part)
50 support member 60 collection part 61 one-way valve 70 collection part 80 support member 90 pipe member (swivel part)
100 Air intake device B Foreign matter

Claims (5)

An intake pipe extending downstream from the air cleaner;
An inner cylinder arranged coaxially in the intake pipe;
An air flow sensor provided in the intake pipe and having an intake inlet in the inner cylinder;
An internal combustion engine comprising: a swirling portion provided in the intake pipe positioned between an outlet of the air cleaner and an inlet of the inner cylinder, and generating a swirling flow around an axis of the intake pipe. Intake device. The intake device for an internal combustion engine according to claim 1, wherein a rectification unit is provided in the inner cylinder upstream of the intake inlet. The intake device for an internal combustion engine according to claim 1 or 2, wherein the intake pipe is provided with a collection portion for collecting the foreign matter urged radially outward by the swirling flow. The internal combustion engine according to claim 3, wherein the collection unit includes a one-way valve that opens when an internal pressure of the intake pipe is higher than an atmospheric pressure and discharges the collected foreign matter to the outside of the intake pipe. Intake device. A recirculation passage for recirculating blowby gas is connected to the intake pipe,
The intake device for an internal combustion engine according to claim 3, wherein the collection unit accumulates oil contained in the blow-by gas returned to the intake pipe.

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