JP2002371822A - Intake device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an intake device for an internal combustion engine capable of suppressing adhering of oil mist to an adsorbent filter with a simple structure and maintaining the adsorbing capability high. SOLUTION: At the inside of an air cleaner 11 provided in mid-way of an intake passage, an air filter element 15 and the adsorbent filter 16 provided to cover the intake passage at the downstream and adsorbing evaporation fuel generated in the internal combustion engine 20 are disposed. In mid-way of the intake passage, a new air introduction passage 51 for communicating an upstream side of the throttle valve 40 with a cylinder head cover 23 of the internal combustion engine 20 and a blowby gas recirculation passage 52 for communicating a downstream side of the throttle valve 40 with the cylinder cover 23 are connected. An oil mist collecting filter 17 which has ventilation and is made of unwoven fabric, for instance, is provided attachably/detachably to/from the intake passage between a connecting part 54 with the new air introduction passage 51 in the intake passage and the adsorbent filter 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake system for an internal combustion engine, and more particularly, to an air intake system having an adsorbent filter such as an activated carbon filter for preventing evaporated fuel from leaking from the intake passage to the outside. The present invention relates to an embodiment of an intake passage structure suitable for being applied to an intake device provided in a vehicle.

[0002]

2. Description of the Related Art Generally, in an internal combustion engine mounted on a vehicle such as an automobile, fuel injected from a fuel injection valve adheres to a wall surface of an intake passage, and evaporated fuel components pass through the intake passage when the engine is stopped. May flow back and be released to the atmosphere.
Further, the evaporated fuel component may slightly leak from the injection hole of the fuel injection valve when the engine is stopped, and the leaked fuel component may flow backward through the intake passage and be released into the atmosphere.

[0003] Therefore, conventionally, an air cleaner having an adsorbent filter such as an activated carbon filter provided downstream of an air filter element has been used in order to prevent such evaporative fuel from being released into the atmosphere via an intake passage. (See, for example, Japanese Utility Model Laid-Open No. 58-113861). According to such an air cleaner, even when the evaporated fuel flows backward through the intake passage when the internal combustion engine is stopped, the evaporated fuel is adsorbed by the adsorbent filter such as the activated carbon filter,
This will not be released to the atmosphere. Further, when a large amount of intake air is introduced into the intake passage via the air cleaner, for example, during high-speed operation of the engine, the fuel component adsorbed on the adsorbent filter such as the activated carbon filter by the intake air. It is released and its adsorption capacity is restored.

[0004]

In the internal combustion engine, lubricating oil for lubricating sliding parts of each component is usually stored in a crankcase in which a crankshaft as an output shaft is housed. ing. A part of the lubricating oil is also supplied to a sliding portion between a camshaft supported at an upper portion of the cylinder head and a bearing of the camshaft. However, the lubricating oil supplied to the sliding part between the camshaft and the bearing part floats in the space formed by the cylinder head and the cylinder head cover as a mist, so-called oil mist. In some cases, the oil mist is discharged to the intake passage together with the blow-by gas. Further, a part of the fuel may leak into the intake passage via a gap between the engine valve insertion hole of the cylinder head and the stem of the engine valve. A part of the lubricating oil is also supplied to a sliding portion between a bore of the cylinder block and a piston ring of a piston that moves up and down in the bore. And the lubricating oil supplied to the sliding portion between the cylinder bore and the piston ring is
Part of it becomes an oil mist and enters the combustion chamber,
A part of the oil mist that has entered the combustion chamber may be blown back to the intake passage when the intake valve is opened. When the oil mist leaks into the intake passage or is blown back in this way, most of the oil mist adheres to the wall surface of the intake passage, etc. There are also things. When the oil mist sometimes enters the air cleaner, the oil mist adheres to fill the pores of the adsorbent filter made of the activated carbon filter or the like. The function as a filter will be reduced.

[0005] Incidentally, since the oil mist has a strong tackiness, once it adheres to the adsorbent filter, a large amount of intake air is introduced through the air cleaner during the above-mentioned high-speed operation of the internal combustion engine or the like. Even when the adsorbent filter is not used. Therefore, the only way to recover the adsorption function is to replace the adsorbent filter itself. However, due to recent regulations based on ultra-low-pollution vehicle exhaust gas standards and evaporative emission control standards, such adsorbent filters have to be replaced. Is often of a structure that cannot be easily removed by a vehicle user or the like.

Further, in an internal combustion engine equipped with a blow-by gas reducing device for discharging and reducing an air-fuel mixture or a combustion gas, that is, blow-by gas, which has entered the crankcase from the combustion chamber, into the intake passage, together with the blow-by gas, the inside of the crankcase is reduced. This problem is particularly serious because oil mist floating in the air may be discharged to the intake passage.

The present invention has been made in view of such circumstances, and has as its object to suppress the adhesion of oil mist to an adsorbent filter with a simple structure, and to maintain an internal combustion engine capable of maintaining a high adsorption capacity. An engine intake device is provided.

[0008]

The means for achieving the above object and the effects thereof will be described below. According to the first aspect of the present invention, an adsorbent filter for adsorbing the evaporated fuel is provided downstream of the air filter element so as to prevent the evaporated fuel generated in the internal combustion engine from being discharged to the outside from the intake passage. In an intake device for an internal combustion engine, an essential point is to provide an oil mist collecting means for collecting oil mist downstream of the adsorbent filter.

According to the above configuration, for example, even when the oil mist flows backward in the intake passage when the internal combustion engine is stopped, for example,
The oil mist that has flowed back is collected by oil mist collecting means. For this reason, the oil mist that has flowed back is prevented from flowing back to the adsorbent filter and adhering thereto. As a result, the adsorption capacity of the adsorbent filter can be maintained at a high level, and the release of the vaporized fuel flowing back through the intake passage to the atmosphere can be suitably suppressed.

According to a second aspect of the present invention, in the intake device for an internal combustion engine according to the first aspect, the oil mist collecting means is detachably provided to the intake passage. I do.

[0011] According to the above configuration, by appropriately replacing the oil mist collecting means, it is possible to maintain the collecting ability of the oil mist collecting means. It can be maintained high for a long time. Further, by replacing only the oil mist collecting means, the replacement cost and the like can be reduced.

According to a third aspect of the present invention, in the intake system for an internal combustion engine according to the first or second aspect, the oil mist collecting means is a filter having air permeability.

According to the above configuration, the adhesion of the oil mist to the adsorbent filter can be suppressed with a simpler structure. Further, it is also possible to suppress a decrease in performance of the internal combustion engine due to a large increase in intake air flow resistance during operation of the engine.

According to a fourth aspect of the present invention, in the intake device for an internal combustion engine according to the third aspect, the filter constituting the oil mist collecting means is made of any one of non-woven fabric, woven fabric, and paper. Make a summary.

According to the above-mentioned structure, the use of any of non-woven fabric, woven fabric, and paper, which is inexpensive and has high workability, can suppress an increase in manufacturing cost. According to a fifth aspect of the present invention, in the intake device for an internal combustion engine according to any one of the first to fourth aspects, the intake passage adjusts an amount of intake air to an engine combustion chamber, and an engine output shaft. A fresh air introduction passage communicating between the crankcase and the upstream side of the throttle valve so as to supply a part of intake air into a crankcase in which a crankshaft is housed; A blow-by gas recirculation passage that recirculates downstream of the valve,
The gist is that the oil mist collecting means is provided between a connection portion of the intake passage with the fresh air introduction passage and the adsorbent filter.

According to the above configuration, even in an internal combustion engine provided with a blow-by gas reducing device for discharging and reducing an air-fuel mixture or a combustion gas, that is, a blow-by gas, which has entered a crankcase from a combustion chamber into an intake passage. Since the mist collecting means is provided upstream of the connection between the intake passage and the fresh air introduction passage and downstream of the adsorbent filter, the adsorbent filter can maintain a higher adsorption capacity.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of an intake device for an internal combustion engine according to the present invention will be described below with reference to FIG.

As shown in FIG. 1, the intake passage has an air cleaner 11 upstream thereof and an internal combustion engine 20 connected to a downstream end thereof. A throttle valve 40 for adjusting the amount of intake air into a combustion chamber 31 of the internal combustion engine 20 described later is provided in the middle of the intake passage. In the middle of the intake passage, the internal combustion engine 2
A blow-by gas reducing device 50 is connected to discharge and reduce blow-by gas such as air-fuel mixture or combustion gas leaked into the crankcase 29 of the No. 0 to the intake passage.

The internal combustion engine 20 includes a cylinder block 2
1, a cylinder head 22 provided to cover the upper surface of the cylinder block 21, and a cylinder head cover 23 provided to cover the upper surface of the cylinder head 22
And an oil pan 24 provided so as to cover the lower surface of the cylinder block 21.

The cylinder block 21 has the same number of cylinder bores 25 as the number of cylinders of the internal combustion engine 20, and each of the cylinder bores 25 accommodates a vertically movable piston 26. The piston 26 is drivingly connected to a crankshaft 28 which is an engine output shaft via a connecting rod 27. Also, the crankshaft 28 is
The oil pan 24 is supported by the lower part of the cylinder block 21 and is supported by the inner surface of the lower part of the cylinder block 21.
And is housed in the crankcase 29 formed by the inner surface of the crankcase 29. In the crankcase 29, lubricating oil 30 for lubricating each sliding portion of the components of the internal combustion engine 20 is stored. A combustion chamber 31 is formed in a space defined by the inner peripheral surface of the cylinder bore 25, the upper surface of the piston 26, and the lower surface of the cylinder head 22.

The cylinder head 22 has an intake port and an exhaust port (both not shown). The intake passage communicates with the combustion chamber 3 through the intake port.
1, and an exhaust passage 32 communicates with the combustion chamber 31 via the exhaust port.

The air cleaner 11 includes a case member that can be divided into three parts, that is, an engine side case member 12, a center case member 13, and an atmosphere side case member 14. Note that an opening 14 a communicating with the atmosphere is formed in the atmosphere-side case member 14. The central case member 13 and the atmosphere-side case member 14 are fastened via, for example, clamps (not shown) that engage with the flanges 13a and 14b. On the other hand, the center case member 13 and the engine-side case member 12 are fastened, for example, at their flanges 13b and 12a by bolts and nuts (both not shown) or the like, which are bolted using a dedicated tool.

The air cleaner 11 includes an air filter element 1 for purifying intake air supplied to the combustion chamber 31.
5 are accommodated so as to cover the intake passage. The air filter element 15 is provided such that its peripheral edge 15 a is sandwiched between the flange 13 a of the central case member 13 and the flange 14 b of the atmosphere-side case member 14. The air cleaner 11 has an adsorbent filter 1 having an adsorbent such as activated carbon provided on the entire surface downstream of the air filter element 15 for adsorbing evaporated fuel flowing backward through the intake passage.
6 are accommodated so as to cover the intake passage. The adsorbent filter 16 is fixed to the central case member 13 so as not to be detached. The adsorbent filter 16 adsorbs fuel vapor generated in the internal combustion engine 20 and flowing backward through the intake passage, and prevents the fuel vapor from being released to the outside.

The blow-by gas reducing device 50
Are a fresh air introduction passage 51 and a blow-by gas recirculation passage 52
And a PCV (Positive Crankcase Ventilation) valve 53 provided in the middle of the blow-by gas recirculation passage 52.
And One end of the fresh air introduction passage 51 is connected upstream of the throttle valve 40 in the intake passage,
The other end is connected to the cylinder head cover 23. On the other hand, one end of the blow-by gas recirculation passage 52 is connected downstream of the throttle valve 40 in the intake passage, and the other end is connected to the cylinder head cover 23. Here, the cylinder head cover 23, the cylinder head 22, and the cylinder block 21 have communication passages 51 for communicating the respective passages 51 and 52 with the crankcase 29.
a, 52a are formed. That is, the intake passage is
The upstream is connected to the crankcase 29 via a fresh air introduction passage 51 and a communication passage 51a, and the downstream thereof is connected to the crankcase 29 via a blow-by gas recirculation passage 52 and a communication passage 52a. The PCV valve 53 is an on-off valve that opens and closes according to the operating state of the internal combustion engine 20. The PCV valve 53 opens when the engine 20 operates at a low rotational speed, and closes when the engine 20 operates at a medium or high rotational speed. ing.

Thus, when the internal combustion engine 20 is operating at a low rotational speed, a part of the intake air flowing through the intake passage is introduced into the crankcase 29 via the fresh air introduction passage 51 and the communication passage 51a. At the same time, the blow-by gas in the crankcase 29 is discharged and reduced to the intake passage via the communication passage 52a, the PCV valve 53, and the blow-by gas recirculation passage 52.

On the other hand, when the internal combustion engine 20 is operated at a medium / high rotational speed, the blow-by gas is not discharged and reduced from the blow-by gas recirculation passage 52 because the PCV valve 53 is closed. Instead, since the amount of intake air flowing through the intake passage is large, blow-by gas in the crankcase 29 is
The exhaust gas is discharged and reduced to the intake passage via the communication passage 51a and the fresh air introduction passage 51 in a manner of being taken by the flow of the intake air flowing through the intake passage. The blow-by gas discharged and reduced to the intake passage is supplied to the combustion chamber 31 together with the intake air during the operation of the internal combustion engine 20, and then discharged outside through the exhaust passage 32 and the like together with the combustion gas.

In this embodiment, an oil mist that flows back through the intake passage when the internal combustion engine 20 is stopped, for example, between the connection portion 54 between the fresh air introduction passage 51 and the intake passage and the adsorbent filter 16. An oil mist collecting filter 17 for collecting oil is housed so as to cover the intake passage. Therefore, as described above, even if oil mist is blown back from the combustion chamber 31 to the intake passage, or if oil mist discharged and reduced from the crankcase 29 to the intake passage flows back through the intake passage. The oil mist flowing backward can be collected by the oil mist collection filter 17. As a result, it is possible to suppress the oil mist from adhering to the adsorbent filter 16, and it is possible to maintain a high adsorbing capacity of the adsorbent filter 16 for adsorbing the evaporated fuel. Further, the oil mist can be collected only by providing the oil mist collection filter 17, and the adhesion of the oil mist to the adsorbent filter 16 can be suppressed with a simple structure.

The oil mist collecting filter 17
Is made of a non-woven fabric having desired air permeability and is formed in a sheet shape. For this reason, it is possible to suppress a large increase in the intake airflow resistance during the operation of the internal combustion engine 20, and to suppress a decrease in the performance of the internal combustion engine 20. In addition, since the nonwoven fabric is inexpensive and has high workability, an increase in the manufacturing cost of the oil mist collection filter 17 can be suppressed.

The oil mist collecting filter 17 is
The peripheral portion 17a is the flange 13 of the central case member 13.
b and the flange 12 a of the engine-side case member 12. Then, the oil mist collection filter 17 releases the screwing of the bolt and the nut for fastening the engine side case member 12 and the central case member 13 using the special tool, and moves the central case member 13 to the atmosphere side. By separating the case members 14 from the engine-side case member 12, the case members 14 can be attached to and detached from the intake passage. For this reason, it becomes possible to replace the oil mist collection filter 17 at an appropriate time, and it is possible to suppress a decrease in the collection ability of the oil mist collection filter 17. As a result, the adsorption capacity of the adsorbent filter 16 can be maintained high for a long period of time. Also, since only the oil mist collection filter 17 can be replaced,
The replacement cost can be kept low.

As described in detail above, according to the intake system for an internal combustion engine according to this embodiment, the following excellent effects can be obtained. (1) It is possible to suppress the oil mist from adhering to the adsorbent filter 16, and it is possible to maintain the adsorbing capacity of the adsorbent filter 16 high.

(2) The oil mist trapping filter 17 can be replaced as needed, and a decrease in the trapping capacity of the oil mist trapping filter 17 can be suppressed.
Further, the adsorbing capacity of the adsorbent filter 16 can be maintained high for a long period of time. Further, only the oil mist collection filter 17 can be replaced, and the replacement cost can be reduced.

(3) The adhesion of oil mist to the adsorbent filter 16 can be suppressed with a simple structure. Further, it is possible to suppress a large increase in the intake air flow resistance during the operation of the internal combustion engine 20, and to suppress a decrease in performance of the internal combustion engine 20.

(4) By forming the oil mist collecting filter 17 from a non-woven fabric which is inexpensive and has high processability, it is possible to suppress an increase in the manufacturing cost. In addition, the said embodiment can also change the structure suitably as follows, for example.

In the above embodiment, the oil mist collecting filter 17 is provided so that the peripheral portion 17a is sandwiched between the flange 12a of the engine side case member 12 of the air cleaner 11 and the flange 13b of the central case member 13. And However, as shown in FIG. 2, for example, the engine side case member 12 and the central case member 13 of the air cleaner 11 are provided.
The receiving portions 19 may be provided near the inner surfaces of the flanges 12a and 13b, respectively, and the oil mist collecting filter 17 may be provided such that the peripheral portion 17a is sandwiched between the receiving portions 19.

The receiving portion 19 is formed on the downstream side of the intake passage, that is, only on the engine side case member 12, and the receiving portion 19 and the peripheral portion 1 of the oil mist collecting filter 17 are formed.
For example, the oil mist collecting filter 17 may be provided by affixing the filter 7a to the filter 7a.

In the above embodiment, the oil mist collecting filter 17 is provided in the air cleaner 11, but the oil mist collecting filter 17 is provided at the position where the connecting portion 54 and the adsorbent filter in the intake passage are provided. 16, any position other than the air cleaner 11 may be used. For example, oil mist collection filter 1
When the position 7 is provided at a position other than the air cleaner 11, for example, a configuration as shown in FIG. 3 can be adopted. That is, the cylinder constituting the intake passage can be divided into a downstream cylinder 60, an upstream cylinder 61, and a connection cylinder 62 that connects these cylinders 60, 61 by fitting. The configuration is such that the filter 17 is fixed in the connection cylinder 62.

In the above embodiment, the oil mist collecting filter 17 may be provided with a core material inside or at least a part of the surface. Instead of providing the core material in the oil mist collection filter 17, a movement restricting member provided in contact with at least the downstream surface of the oil mist collection filter 17, for example, formed in a lattice shape or a honeycomb shape, is used. It may be configured to be disposed in the intake passage.

In the above embodiment, the oil mist collecting filter 17 may be formed in, for example, a wave shape. In the above embodiment, the oil mist collection filter 17 is formed of a nonwoven fabric. However, the oil mist collection filter 17 is not limited to a nonwoven fabric. The oil mist collection filter 17 may be formed of a material having air permeability such as woven fabric, paper, sponge, or the like.

In the above embodiment, the oil mist collecting filter 17 is provided so as to be detachable from the intake passage. However, the oil mist collecting filter 17 may be provided so as not to be detachable from the intake passage. Good.

In the above embodiment, the adsorbent filter 16 may be provided at a position other than inside the air cleaner 11 in the intake passage. In the above embodiment, the blow-by gas returning device 50
May have a configuration in which one of the communication passages 51a and 52a is omitted.

In the above embodiment, the example of the intake device in which the fresh air introduction passage 51 and the blow-by gas recirculation passage 52 of the blow-by gas reduction device 50 are connected has been described. However, the present invention can be similarly applied to an intake device having no passages 51 and 52. In this case, the communication paths 51a and 52a of the internal combustion engine 20 are omitted. In addition, the position where the oil mist collection filter 17 is provided may be provided at any position as long as it is downstream of the adsorbent filter 16 irrespective of the upstream or downstream of the throttle valve 40.

Other technical ideas which can be understood from the above embodiment and the above description will be described below together with their effects. (A) In the intake device for an internal combustion engine according to any one of claims 3 to 5, the filter constituting the oil mist collecting means is formed in a sheet shape, and at least one of the inside and the surface of the filter is formed. An intake device for an internal combustion engine, comprising: a core member in a portion.

According to the above configuration, even if the pressing force due to the flow of the intake air in the intake passage acts on the filter constituting the oil mist collecting means, the vicinity of the center line of the intake passage in the filter is close to the intake line. Displacement in the form of being stretched in the flow direction is suppressed. Therefore, it is possible to prevent the filter from being broken or forming a large hole in the filter due to the pressing force. In addition, by forming the filter in a sheet shape as described above, it is possible to preferably suppress an increase in intake airflow resistance during operation of the internal combustion engine. In the case where a paper or a woven fabric having air permeability is used as the filter, such an effect is remarkable.

[Brief description of the drawings]

FIG. 1 is a partial sectional view showing a schematic configuration of an intake device and an internal combustion engine according to an embodiment of the present invention.

FIG. 2 is a partially enlarged cross-sectional view showing the vicinity of an oil mist collection filter according to another example in an enlarged manner.

FIG. 3 is a partially enlarged cross-sectional view showing the vicinity of an oil mist collection filter according to still another example in an enlarged manner.

[Explanation of symbols]

11 ... air cleaner, 12 ... engine side case member, 12
a, 13a, 13b, 14b: flange, 13: central case member, 14: atmosphere side case member, 14a: opening, 1
5 air filter element, 15a, 17a peripheral part, 16 adsorbent filter, 17 oil mist collection filter, 20 internal combustion engine, 21 cylinder block, 2
2 ... cylinder head, 23 ... cylinder head cover, 2
4 oil pan, 25 cylinder bore, 26 piston, 27 connecting rod, 28 crankshaft, 29 crankcase, 30 lubricating oil, 31 combustion chamber, 32 exhaust passage, 40 throttle valve, 50
... Blow-by gas reduction device, 51 ... New air introduction passage, 51
a, 52a: communication passage, 52: blow-by gas recirculation passage,
53 ... PCV valve, 54 ... Connection.

Claims (5)

[Claims] 1. An engine according to claim 1, wherein an adsorbent filter for adsorbing the evaporated fuel is provided downstream of the air filter element so as to prevent the fuel vapor generated in the internal combustion engine from being discharged from the intake passage to the outside. An intake device for an internal combustion engine, comprising: an oil mist collecting means for collecting oil mist downstream of the adsorbent filter. 2. An intake device for an internal combustion engine according to claim 1, wherein said oil mist collecting means is provided detachably with respect to said intake passage. 3. The intake device for an internal combustion engine according to claim 1, wherein the oil mist collecting means is a filter having air permeability. 4. The intake device for an internal combustion engine according to claim 3, wherein the filter constituting the oil mist collecting means is made of one of non-woven fabric, woven fabric and paper. 5. An intake device for an internal combustion engine according to claim 1, wherein said intake passage adjusts an amount of intake air to an engine combustion chamber, and a crankshaft as an engine output shaft. A fresh air introduction passage communicating between the upstream side of the throttle valve and the crankcase so as to supply a part of intake air into a crankcase in which the blow-by gas in the crankcase is supplied downstream of the throttle valve. A blow-by gas recirculation passage that recirculates the oil, and the oil mist collecting means is provided between the connection portion of the intake passage with the fresh air introduction passage and the adsorbent filter. An intake device for an internal combustion engine.