JP2020037875A - Intake structure of internal combustion engine - Google Patents

Abstract

To solve such the problem that in an air cleaner, sometimes foreign matters in the cleaner are not discharged over a long period of time.SOLUTION: An air cleaner 30 for removing foreign matters in intake air is arranged at an upstream side of a compressor 24 of a turbocharger 20 in an intake passage 12. An air bypass passage 14 extends from a downstream side of the compressor 24 in the intake passage 12, and is connected to the air cleaner 30. An air bypass valve 28 which opens when a pressure at a downstream side of the compressor 24 of the intake passage 12 becomes higher than a pressure at an upstream side of the compressor 24 by a specified pressure, is attached to the middle of the air bypass passage 14. A discharge valve 40 for switching communication states between an upstream-side space S1 and the outside of the air cleaner 30 is arranged at an upstream side of a filter 32 in the air cleaner 30. The discharge valve 40 opens according as the pressure of the upstream-side space S1 becomes higher than the pressure of the outside of the air cleaner 30.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an intake structure for an internal combustion engine.

  The internal combustion engine of Patent Literature 1 includes an intake passage for introducing intake air into a cylinder. An air cleaner for removing foreign substances in the intake air is provided in the middle of the intake passage. A filter is mounted inside the air cleaner, and the filter separates the internal space of the air cleaner into an upstream side and a downstream side. A discharge door for discharging foreign matters accumulated in the air cleaner to the outside of the air cleaner is attached to the air cleaner upstream of the filter.

  In the internal combustion engine of Patent Literature 1, when a large amount of foreign matter accumulates on the upstream side of the filter in the internal space of the air cleaner, it becomes difficult for the intake air to pass through the filter, and the pressure on the downstream side of the filter decreases. In the internal combustion engine of Patent Literature 1, the discharge door is configured to open when the pressure downstream of the filter in the internal space of the air cleaner becomes appropriately low.

JP 2008-014286 A

  In the internal combustion engine of Patent Literature 1, a large amount of foreign matter accumulates on the upstream side of the filter in the internal space of the air cleaner, and the discharge door is not opened unless the pressure on the downstream side of the filter becomes low. That is, in the internal combustion engine of Patent Literature 1, when there is not much foreign matter stored in the internal space of the air cleaner, the foreign matter is not discharged for a long time. Therefore, there is a need for a structure capable of periodically discharging foreign matter from the air cleaner even if the amount of foreign matter stored in the internal space of the air cleaner is small.

  In order to solve the above-mentioned problems, the present invention relates to an intake structure applied to an internal combustion engine with a turbocharger, wherein the intake structure is provided upstream of a compressor of the turbocharger in an intake passage of the internal combustion engine, and foreign matters in intake air are provided. An air cleaner that removes air from the compressor, an air bypass passage extending from the downstream side of the compressor in the intake passage and connected to the air cleaner, and provided in the middle of the air bypass passage and downstream of the compressor in the intake passage. An air bypass valve that opens when the pressure of the compressor becomes higher than the pressure upstream of the compressor by a specified pressure or more, and a filter that collects foreign substances is disposed inside the air cleaner. The filter makes the internal space of the air cleaner an upstream space and a downstream space. The air cleaner is provided with a discharge valve for switching a communication state between the upstream space and the outside of the air cleaner, and the air bypass passage is provided upstream of the filter in the air cleaner. And the exhaust valve is opened when the pressure in the upstream space becomes higher than the pressure outside the air cleaner.

  According to the above configuration, when the air bypass valve is opened, relatively high-pressure intake air flows into the upstream space of the air cleaner. Then, the pressure in the upstream space increases, and the discharge valve opens. As a result, it is possible to discharge the foreign matter stored in the space on the upstream side of the air cleaner via the discharge valve. The situation in which the air bypass valve can be opened is a situation in which the amount of intake air supplied to the cylinder decreases, and occurs relatively frequently. Therefore, it is unlikely that a foreign substance in the air cleaner cannot be discharged for a long time, and the foreign substance in the air cleaner can be discharged periodically.

The schematic diagram of an intake structure. Sectional drawing of an air cleaner and its peripheral structure. FIG. 3 is a plan view near the discharge port of the air cleaner.

  Hereinafter, an embodiment of the intake structure will be described with reference to the drawings. In the following description, the terms “upstream” and “downstream” refer to the upstream and downstream in the intake and exhaust directions. In addition, the vertical direction indicates the vertical direction of the vehicle when the internal combustion engine is mounted on the vehicle.

First, a schematic configuration of the internal combustion engine 10 will be described.
As shown in FIG. 1, an intake passage 12 for supplying intake air to the cylinder 11 of the internal combustion engine 10 is connected to the cylinder 11. Further, an exhaust passage 13 for discharging exhaust gas from the cylinder 11 is connected to the cylinder 11. A turbocharger 20 is attached to the intake passage 12 and the exhaust passage 13. Specifically, the housing 21 of the turbocharger 20 is attached so as to straddle the intake passage 12 and the exhaust passage 13. A turbine 22 that rotates by utilizing the flow of exhaust gas in the exhaust passage 13 is disposed on the exhaust passage 13 side inside the housing 21. A compressor 24 is connected to the turbine 22 via a shaft 23. The compressor 24 is located inside the housing 21 on the side of the intake passage 12. The compressor 24 rotates integrally with the turbine 22. Therefore, when the turbine 22 is rotated by the flow of the exhaust gas in the exhaust passage 13, the compressor 24 is also integrally rotated, and the intake air compressed by the compressor 24 is pumped to the downstream side.

  An air cleaner 30 for removing foreign matter in the intake air is attached to the intake passage 12 upstream of the compressor 24. Downstream of the compressor 24 in the intake passage 12, an intercooler 26 for cooling the intake air that has been heated by being compressed by the compressor 24 is attached. Further, a throttle valve 27 for adjusting the amount of intake air supplied into the cylinder 11 is attached downstream of the intercooler 26 in the intake passage 12.

  An air bypass passage 14 extends from the intake passage 12 downstream of the compressor 24 and upstream of the intercooler 26. The downstream end of the air bypass passage 14 is connected to the air cleaner 30. In this embodiment, the air bypass passage 14 is constituted by a tubular hose. An air bypass valve 28 is attached in the middle of the air bypass passage 14. In the air bypass valve 28, the pressure in the air bypass passage 14 on the upstream side (compressor 24 side) of the air bypass valve 28 is higher than the pressure on the downstream side (air cleaner 30) of the air bypass valve 28 by a specified pressure or more. The valve is opened when This specified pressure is lower than the pressure at which the intake air flows backward from the downstream side of the compressor 24 in the intake passage 12 to the upstream side of the compressor 24 in the intake passage 12 via the housing 21 of the turbocharger 20. Set to pressure.

  Since the upstream end of the air bypass passage 14 is connected to the downstream side of the compressor 24 in the intake passage 12, the pressure of the air bypass passage 14 upstream of the air bypass valve 28 is reduced by the compressor in the intake passage 12. This corresponds to a pressure downstream of 24. Further, since the downstream end of the air bypass passage 14 is connected to the upstream side of the compressor 24 in the intake passage 12, the pressure of the air bypass passage 14 downstream of the air bypass valve 28 is reduced by the compressor in the intake passage 12. This corresponds to a pressure upstream of 24.

Next, the air cleaner 30 and its peripheral structure will be described more specifically.
As shown in FIG. 2, the air cleaner 30 includes a main body case 31 having a rectangular box shape as a whole. Inside the main body case 31, a filter 32 (sometimes called an element) for collecting foreign matter in the intake air is arranged. The filter 32 is configured by, for example, stacking or folding a plurality of nonwoven fabrics. The filter 32 is disposed substantially at the center in the vertical direction of the main body case 31, and the inside of the main body case 31 is located on the upstream side of the intake passage 12 and below the filter 32, and an upstream space S 1. It is partitioned into a downstream space S2 located downstream of the intake passage 12 and above the filter 32.

  The lower wall portion of the main body case 31 is provided with a recessed portion 31A that is recessed downward. Specifically, a part of the lower wall of the main body case 31 is curved so as to expand toward the lower side. The curved portion is a concave portion 31A that is recessed below the non-curved portion. In this embodiment, approximately half of the lower wall of the main body case 31 on the side opposite to the side where the intake path 12 on the upstream side is connected (the right side in FIG. 2) is a recess 31A.

  A tubular mounting port 33 protrudes from a wall of the side wall of the main body case 31 opposite to the side where the upstream intake passage 12 is connected. The mounting port 33 is located below the filter 32. Therefore, the attachment port 33 communicates the upstream space S1 of the internal space of the main body case 31 with the outside of the main body case 31. The mounting opening 33 extends substantially linearly. The mounting opening 33 extends obliquely with respect to the horizontal plane such that the mounting opening 33 is located closer to the protruding tip side and lower below the inner space (upstream space S1) of the main body case 31. As described above, since the mounting port 33 is inclined with respect to the horizontal plane, the center axis J of the mounting port 33 intersects with the recess 31 </ b> A of the wall of the main body case 31. In the present embodiment, the mounting opening 33 is formed integrally with the main body case 31.

  The air bypass passage 14 is connected to the mounting port 33 so as to surround a part of the protruding tip side of the mounting port 33 from the outside in the radial direction. In addition, a band clip 34 is attached to a connection portion between the attachment port 33 and the air bypass passage 14 so as to surround them from the radial outside. The band clip 34 is fixed so that the air bypass passage 14 does not come off from the mounting opening 33.

  In the recess 31 </ b> A of the main body case 31, a discharge port 35 communicating the upstream space S <b> 1 of the main body case 31 and the outside of the main body case 31 penetrates. The discharge port 35 has a substantially circular shape in plan view. The center of the opening of the discharge port 35 is located on the central axis J of the mounting port 33.

  As shown in FIG. 3, a projecting piece 36 extends from the opening edge of the discharge port 35 toward the center of the opening of the discharge port 35. The protruding tip of the protruding piece 36 is located at the center of the opening of the discharge port 35. A circular through-hole 36 </ b> A in a plan view penetrates the protruding tip of the protruding piece 36.

  As shown in FIG. 2, a discharge valve 40 for closing the discharge port 35 is attached to the protruding piece 36. The discharge valve 40 includes a disc-shaped valve element 41 and a shaft 42 extending from the valve element 41. The outer diameter of the valve body 41 is larger than the inner diameter of the discharge port 35. In FIG. 3, the outer edge of the valve element 41 is virtually illustrated by a two-dot chain line. A substantially cylindrical shaft portion 42 protrudes from the center of the valve body 41. The outer diameter of the shaft portion 42 on the base end side (the valve body 41 side) is substantially the same as the inner diameter of the through hole 36 </ b> A of the protruding piece 36. Further, the outer diameter of the shaft portion 42 on the protruding tip side is larger than the inner diameter of the through hole 36 </ b> A of the protruding piece 36. The material of the discharge valve 40 is a material having a relatively high elastic modulus, such as natural rubber, synthetic rubber, and elastomer.

  The discharge valve 40 is fixed to the main body case 31 by inserting the shaft portion 42 into the through hole 36A of the protruding piece 36 so that the valve element 41 is positioned outside the main body case 31 (the recess 31A). I have. When the shaft portion 42 is inserted into the through hole 36A of the protruding piece 36, the shaft portion 42 is inserted while the projecting distal end side is elastically deformed. Then, when the protruding tip side of the shaft portion 42 passes through the through hole 36A, the protruding tip side of the shaft portion 42 is elastically restored, and the outer diameter increases. As a result, the valve body 41 does not easily fall off from the protruding piece 36.

The operation and effect of the present embodiment will be described.
When the internal combustion engine 10 is driven and the intake air is supplied into the cylinder 11, the intake air flows through the intake passage 12. When foreign matter such as dust is contained in the intake air taken into the intake passage 12 from outside air, the foreign matter is collected by the filter 32 of the air cleaner 30. Part of the foreign matter collected by the filter 32 falls on the lower wall of the main body case 31 of the air cleaner 30 according to gravity. In addition, foreign matter that has once fallen on the lower wall of the main body case 31 may be wound up by the flow of the intake air and adhere to the filter 32. As described above, when the foreign matter re-adheres to the filter 32, the filter 32 may be clogged.

  Here, in the present embodiment, the hollow portion 31A is provided in the main body case 31. The recess 31A is recessed below other portions, and it is difficult for the flow of the intake air flowing through the inside of the main body case 31 to reach the inside of the recess 31A. That is, the flow of the intake air stays inside the recessed portion 31A, and it is difficult for foreign matters to be wound up by the intake air. Therefore, most of the foreign matter that has fallen accumulates on the bottom surface of the recess 31A.

  Further, when the internal combustion engine 10 is driven and the intake air is being supplied to the cylinder 11, the pressure in the intake passage 12 on the upstream side of the compressor 24 is slightly negative with respect to the atmospheric pressure. Therefore, the valve element 41 of the discharge valve 40 is pressed against the opening edge of the discharge port 35 by the atmospheric pressure. Therefore, in the normal driving state of the internal combustion engine 10, the discharge port 35 of the main body case 31 of the air cleaner 30 is closed by the discharge valve 40, and foreign matter enters the inside of the air cleaner 30 via the discharge port 35. There is no.

  Incidentally, there is a case where control is performed such that the amount of intake air supplied to the cylinder 11 during the operation of the internal combustion engine 10 sharply decreases. Specifically, for example, if the accelerator pedal of the vehicle is depressed to some extent, the opening of the throttle valve 27 is correspondingly large, and a large amount of intake air is supplied to the cylinder 11. At this time, the turbine 22 of the turbocharger 20 is rotated by the flow of the exhaust gas in order to secure the amount of intake air supplied to the cylinder 11. Further, the compressor 24 also rotates integrally with the turbine 22.

  In such a situation, when the accelerator pedal of the vehicle is released from the depressed state, the amount of intake air supplied to the cylinder 11 is reduced, so that the opening of the throttle valve 27 becomes smaller than before. On the other hand, the compressor 24 of the turbocharger 20 cannot be stopped immediately, but keeps rotating for a while due to inertia. Then, on the downstream side of the compressor 24 in the intake passage 12, although only a small amount of intake air is supplied to the cylinder 11, the intake air is pressure-fed from the compressor 24. Therefore, the pressure downstream of the compressor 24 in the intake passage 12 becomes considerably high.

  The pressure downstream of the compressor 24 in the intake passage 12 becomes higher, and the pressure upstream of the air bypass valve 28 in the air bypass passage 14 is higher than the pressure downstream of the air bypass valve 28 by a specified pressure or more. Then, the air bypass valve 28 opens. Then, the intake air flows through the air bypass passage 14, and the high-pressure intake air flows into the upstream space S <b> 1 in the air cleaner 30.

  When the high-pressure intake air flows into the upstream space S1, the pressure in the upstream space S1 becomes higher than the atmospheric pressure. Then, the valve element 41 of the discharge valve 40 is pushed by the pressure of the upstream space S <b> 1, and the valve element 41 and the projecting piece 36 are elastically deformed so as to bend toward the outside of the main body case 31. As a result, the discharge valve 40 is opened, and the intake air flows out through the discharge port 35 to the outside. At this time, along with the flow of the intake air flowing to the outside, the foreign matters accumulated in the recess 31A are also discharged to the outside together.

  As described above, in the present embodiment, as described above, when the amount of intake air supplied to the cylinder 11 is reduced, such as when the accelerator pedal of the vehicle is depressed from a depressed state, the internal air cleaner 30 is closed. Foreign matter can be ejected. The situation in which the amount of intake air supplied to the cylinder 11 decreases occurs relatively frequently, for example, when the vehicle decelerates. Therefore, it is unlikely that a foreign substance in the air cleaner 30 cannot be discharged for a long time, and the foreign substance in the air cleaner 30 can be discharged periodically.

  Moreover, in the present embodiment, the discharge valve 40 is located on the central axis J of the attachment port 33 to which the air bypass passage 14 is connected. Therefore, the intake air flowing into the upstream space S1 of the main body case 31 from the attachment port 33 reaches the discharge valve 40 without being blocked by the wall of the main body case 31. Therefore, the exhaust valve 40 is easily opened by the wind pressure of the intake air flowing into the upstream space S1. Further, after the discharge valve 40 is opened, the intake air flows from the mounting port 33 to the outside of the main body case 31 via the discharge port 35 vigorously, so that it is easy to discharge more foreign substances to the outside of the main body case 31. Become.

This embodiment can be implemented with the following modifications. The present embodiment and the following modifications can be implemented in combination with each other within a technically consistent range.
The shape of the main body case 31 in the air cleaner 30 can be appropriately changed as long as the filter 32 can be disposed inside. For example, the shape of the main body case 31 may be cylindrical.

  The arrangement of the filter 32 in the air cleaner 30 is not limited as long as the internal space of the air cleaner 30 can be partitioned into the upstream space S1 and the downstream space S2. Further, the upstream space S1 and the downstream space S2 do not have to be arranged in the vertical direction. That is, the filter 32 may be arranged so that the upstream space S1 and the downstream space S2 are arranged in the horizontal direction.

  The depression 31A may be omitted from the main body case 31 of the air cleaner 30. In this case, the foreign matter in the main body case 31 easily accumulates in a portion of the lower wall portion of the main body case 31 where the flow of the intake air tends to stagnate, for example, a corner at a boundary between the lower wall portion and the side wall portion.

-The material of the filter 32 is not limited to a non-woven fabric, but may be air-permeable paper (filter paper), foamed plastic, or a combination thereof.
The attachment port 33 does not necessarily have to extend linearly, and may be bent or curved in the middle. In addition, even when the attachment port 33 is bent or curved, as long as the discharge valve 40 is located on the central axis of the opening of the attachment port 33 on the body case 31 side, the same as in the above embodiment. In addition, the intake air flowing into the main body case 31 from the air bypass passage 14 can easily reach the discharge valve 40 directly.

  The center of the opening of the discharge port 35 does not have to be located on the central axis J of the mounting port 33. If any portion within the opening range of the discharge port 35 is located on the central axis J of the mounting port 33, the intake air flowing into the main body case 31 from the air bypass passage 14 easily reaches the discharge valve 40.

  Further, the position of the discharge port 35 can be set independently of the center axis J of the mounting port 33. For example, the discharge port 35 may be provided in a side wall portion of the side wall portion of the main body case 31 on which the attachment port 33 is provided. Even if the discharge port 35 is not located on the center axis J of the mounting port 33, if the intake air flows into the main body case 31 from the air bypass passage 14, the pressure of the upstream space S1 in the main body case 31 becomes the atmospheric pressure. Be larger. Therefore, the discharge valve 40 opens.

  -The shape of the discharge port 35 and the shape of the valve element 41 in the discharge valve 40 are not limited to the example of the above embodiment. For example, the shape of the outlet 35 in a plan view may be an elliptical shape or a polygonal shape. Further, the shape of the valve body 41 of the discharge valve 40 in plan view is not limited as long as it can cover the entire opening of the discharge port 35.

  In the discharge valve 40, an urging member for pressing the valve body 41 toward the main body case 31 may be added. When an urging member is added, the urging force of the urging member can be used to open the discharge valve 40 when high-pressure intake air flows into the upstream space S1 of the main body case 31 via the air bypass passage 14. It may be adjusted to such an urging force. If the valve element 41 is pressed toward the main body case 31 as in this modified example, even if a slight vibration or the like acts on the air cleaner 30, the discharge valve 40 slightly opens due to the vibration. Can be prevented.

  DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 11 ... Cylinder, 12 ... Intake passage, 13 ... Exhaust passage, 14 ... Air bypass passage, 20 ... Turbocharger, 21 ... Housing, 22 ... Turbine, 23 ... Shaft, 24 ... Compressor, 26 ... Intercooler , 27 ... throttle valve, 28 ... air bypass valve, 30 ... air cleaner, 31 ... body case, 31A ... recessed part, 32 ... filter, 33 ... mounting port, 34 ... band clip, 35 ... discharge port, 36 ... projecting piece, 36A: Through-hole, 40: Discharge valve, 41: Valve body, 42: Shaft, S1: Upstream space, S2: Downstream space, J: Center axis.

Claims (1)

An intake structure applied to an internal combustion engine with a turbocharger,
An air cleaner that is provided upstream of a compressor of the turbocharger in an intake passage of an internal combustion engine and removes foreign matter in intake air;
An air bypass passage extending from the downstream side of the compressor in the intake passage and connected to the air cleaner;
An air bypass valve that is provided in the middle of the air bypass passage and that opens when a pressure downstream of the compressor in the intake passage becomes higher than a pressure upstream of the compressor by a specified pressure or more. ,
Inside the air cleaner, a filter that collects foreign matters is arranged, and the internal space of the air cleaner is partitioned into an upstream space and a downstream space by the filter,
The air cleaner is provided with a discharge valve that switches a communication state between the upstream space and the outside of the air cleaner,
The air bypass passage is connected to an upstream side of the filter in the air cleaner,
The intake structure according to claim 1, wherein the discharge valve opens in response to a pressure in the upstream space being higher than a pressure outside the air cleaner.