JP3904425B2 - Blow-by gas processing device for internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a blow-by gas processing apparatus for an internal combustion engine configured to return blow-by gas to a suction passage from a crankcase and / or a cylinder head side via a breather chamber and a breather tube.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, blow-by gas processing apparatuses in which an oil pan, a cylinder head, and the like communicate with an intake passage through a breather chamber and a breather tube to return blow-by gas to the intake passage are well known.
[0003]
Since the breather tube is exposed to the outside, if the outside air temperature is low, the blow-by gas temperature is unnecessarily lowered, the moisture contained in the blow-by gas freezes, and the cross-sectional area of the passage is reduced. Therefore, various ideas have been made.
[0004]
For example, in JP-A-8-246837, a connection portion of a PCV hose (breather tube) for introducing blow-by gas with an intake pipe is made of nylon resin , fluororesin , acrylic resin, etc., which has low thermal conductivity and easily peels off ice. There is disclosed a structure formed of a material, and the PCV hose itself is formed of elastic rubber, plastic or the like having low thermal conductivity.
[0005]
Further, for example, in Japanese Patent No. 3106826, a cooling water sub-passage different from the engine cooling water main passage is arranged in parallel to a breather passage pipe (breather tube), and the pipe is added with warm water flowing through the inside. A warming structure is disclosed.
[0006]
Further, for example, Japanese Utility Model Laid-Open No. 5-30410 discloses a blow-by gas circulation hose (breather tube) having a double pipe structure of an outer pipe and an inner pipe, and a passage between the inner pipe and between the inner pipe and the outer pipe. Discloses a structure in which blow-by gas is allowed to flow.
[0007]
[Problems to be solved by the invention]
The structure in which the above-mentioned heat conductivity is low and the ice is easily peeled off and the PCV hose itself is made of an elastic material having low heat conductivity (Japanese Patent Laid-Open No. 8-246837) can be constructed at low cost. Although it is highly effective in preventing icing at the intake pipe connection, the PCV hose is not directly capable of preventing icing in the gas pipeline because it is directly exposed to low-temperature outside air, and is insufficient as an icing prevention structure. It is.
[0008]
Further, the structure (Japanese Patent No. 3106826) in which the pipe cooling water sub-passage of the breather passage is arranged in parallel requires a lot of space in the layout, and the structure is complicated, and the number of parts and the number of assembling steps increase. For this reason, the cost is remarkably increased as compared with the conventional structure.
[0009]
Furthermore, the blow-by gas circulation hose has a double-pipe structure, and the blow-by gas flows through the passage inside the inner pipe and between the inner pipe and the outer pipe (Japanese Utility Model Laid-Open No. 5-30410) is in direct contact with the low temperature outside air. Although the inner pipe does not freeze, the outer pipe is directly exposed to low-temperature outside air, so it is impossible to prevent icing in the passage between the inner pipe and the outer pipe, resulting in a narrow cross-sectional area of the flow path. This is also insufficient as an anti-icing structure. Further, when the passage between the inner pipe and the outer pipe is frozen, the inside of the inner pipe may be cooled.
[0010]
In addition, it is conceivable to shorten the length of the breather tube, but in that case, both ends of the breather tube, for example, the cylinder head cover and the air cleaner or air flow tube must be arranged close to each other, and the surrounding structure and arrangement are also reduced. It is not realistic because it affects the design and the design freedom is significantly reduced.
[0011]
The present invention has been devised to solve the above-mentioned problems of the prior art, and is a blow-by of an internal combustion engine that can easily prevent the moisture of the blow-by gas from freezing due to a temperature drop with a simple structure. An object is to provide a gas processing apparatus.
[0012]
[Means for Solving the Problems]
According to the first aspect of the present invention, the blow-by gas is returned from the crankcase and / or the cylinder head 1 side to the intake passage (in the vicinity of the intake outlet of the air cleaner 7) via the breather tube 8. and a blow-by gas treatment device for an internal combustion engine is, the breather tube 8, the inner tube 11 and and the the inner pipe 11 has a heat-insulating layer 13 made of an air layer between the outer tube 12 is blow-by gas One end of the breather tube 8 is inserted into the breather tube 8 and the other end is inserted into a cylindrical connecting portion 14 provided on the intake passage side (air cleaner 7). The joint member is connected to the passage, and the joint member forms an annular spacer that also serves as a seal on the front end side of the cylindrical connection portion 14. A hook-shaped part 17 formed integrally with the joint member 15 and an O-ring 19 provided at a position spaced apart from the hook-shaped part 17 in the axial direction, and between the hook-shaped part 17 and the O-ring 19 of the joint member It is achieved by providing a blow-by gas processing apparatus for an internal combustion engine, characterized in that a heat insulating layer 20 made of an air layer is defined between an outer peripheral surface therebetween and an inner peripheral surface of the cylindrical connecting portion 14. The
[0013]
According to the first aspect of the present invention, since the inner tube 11 is not directly exposed to the low-temperature outside air by the heat insulating layer 13 between the outer tube 11 and the inner tube 12 even at a very low temperature, The temperature does not drop so much that its moisture reaches freezing. Further, a heat insulating layer 20 made of an air layer is defined between the outer peripheral surface of the joint member 15 inserted into the breather tube 8 and the cylindrical connecting portion 14 provided on the intake passage side and the inner peripheral surface of the cylindrical connecting portion 14. As a result, the connection portion between the intake passage and the joint member is also insulated, so that the breather tube 8 and its connection portion, that is, the entire blow-by gas passage, are thermally insulated from the outside, and icing of moisture can be reliably prevented. And since the heat-transfer from the air cleaner 7 side is received by the bowl-shaped part 17, the heat receiving area with respect to the air cleaner 7 side is minimized, and it can suppress that the joint member 15 is cooled.
[0014]
The invention of claim 2 is characterized in that the breather tube 8 and the cylindrical joint member 15 are made of a material having low thermal conductivity. Thereby, even if some freezing occurs in the inner tube 11, the generated ice is easily peeled off.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[0016]
FIG. 1 is a front perspective view of an in-line four-cylinder engine as an internal combustion engine to which the present invention is applied. At the front of the engine, there are an intake manifold 2 connected to an intake port provided in the cylinder head 1, and a surge tank 3 connected to the intake upstream end of the intake manifold 2 and disposed at the lower part of the intake manifold 2. And the throttle body 4 connected to the intake inlet opening on the upper surface of the right end portion of the surge tank 3 in the figure, and the air flow having one end connected to the upper end of the throttle body 4 and the other end connected to the air cleaner 7. A tube 6 is provided. Further, one end of a breather tube 8 constituting a blow-by gas processing device is connected to the vicinity of the intake outlet of the air cleaner 7 so as to return the blow-by gas to the intake passage. The other end of the breather tube 8 is connected to a breather chamber (not shown) in the cylinder head cover 9.
[0017]
The air cleaner 7 is connected to an outside air inlet (not shown) through an air duct 10.
[0018]
2 is an enlarged cross-sectional view showing a connection portion of the breather tube to the air cleaner in the engine of FIG. 1, and FIG. 3 shows a connection portion of the breather tube to the air cleaner as viewed in the direction of the line III-III in FIG. It is an expanded sectional view. The breather tube 8 has a double tube structure of an inner tube 11 and an outer tube 12, and blow-by gas passes through the inner tube 11. A heat insulating layer 13 made of an air layer is defined between the inner tube 11 and the outer tube 12. The heat insulating layer 13 is defined by providing a protruding spacer at an appropriate position between the inner tube 11 and the outer tube 12 or by providing a protrusion extending in the axial direction. The inner tube 11 is made of a material having low thermal conductivity such as nylon resin, rubber, fluororesin , acrylic resin, and the outer tube 12 is made of a material having high heat insulation properties such as foam rubber.
[0019]
The breather tube 8 is connected by a cylindrical joint member 15 that is bent to a cylindrical connection portion 14 provided in the vicinity of the intake outlet of the air cleaner 7. The joint member 15 is made of a material having low thermal conductivity such as nylon resin, and one end is inserted in the breather tube 8 in advance, and the other end side cylindrical protruding portion 15a is inserted in the cylindrical connecting portion 14, and FIG. As shown, the breather tube 8 is placed in the vicinity of the intake outlet of the air cleaner 7 by elastically engaging the engaging protrusion 15b provided on a part of the peripheral surface with the engaging hole 14a formed in the cylindrical connecting portion 14. To connect to. Here, since the cylindrical connecting portion 14 is opened at an angle θ on the downstream side of the intake flow, the blow-by gas is smoothly mixed with the intake air without disturbing the intake flow.
[0020]
As the annular spacer also serving as a seal, a flange-like portion 17 that gradually becomes thinner toward the tip (outer peripheral side) is formed in the rush portion 15 a of the joint member 15. In addition, an O-ring 19 sandwiched between a pair of annular convex portions 18a and 18b is provided as a circular spacer that also serves as a seal at a position that is spaced apart from the flange portion 17 toward the base of entry. The flange-shaped portion 17 and the O-ring 19 define a heat insulating layer 20 made of an air layer between the outer peripheral surface of the entry portion 15 a and the inner peripheral surface of the cylindrical connecting portion 14. Here, the heat transfer from the air cleaner 7 side is received not by the O-ring but by the bowl-shaped part 17, and the bowl-shaped part 17 is gradually thinned toward the tip (outer peripheral side) to form a lip shape. Since it is in line contact with the cylindrical connecting portion 14, the heat receiving area from the air cleaner side is minimized, and it is possible to suppress the cooling of the blow-by gas discharge port portion of the joint member 15 in particular.
[0021]
As shown in FIG. 3, the joint member 15 is bent from the middle thereof. This is because the breather tube 8 is curved, and the heat insulating layer 13 and the inner tube 11 between the inner tube 11 and the outer tube 12. This is a device for extending the breather tube 8 as linearly as possible in order to prevent the cross-sectional area of the inner blowby gas passage from being reduced.
[0022]
FIG. 5 is a cross-sectional view showing a connecting portion of the breather tube 8 on the cylinder head cover 9 side. A rubber tubular connection member 21 is provided at the connection end of the breather tube 8. The connection member 21 is fixed by bonding or the like in a state where one end of the connection member 21 is sandwiched between the inner tube 11 and the outer tube 12 of the breather tube 8 in advance. The other end of the connecting member 21 is fitted into the cylindrical connecting portion 23 on the cylinder head cover 9 side, and the band 24 is fastened and fixed.
[0023]
【The invention's effect】
As is apparent from the above description, according to the blow-by gas processing apparatus for an internal combustion engine according to the configuration of claim 1 of the present invention , the inner tube is kept at an extremely low temperature by the heat insulating layer between the outer tube and the inner tube. Since it is not directly exposed to low-temperature outside air, the temperature of the blow-by gas does not decrease so that the moisture reaches freezing. In addition, by defining a heat insulating layer composed of an air layer between the outer peripheral surface of the joint member inserted into the breather tube and the cylindrical connecting portion provided on the intake passage side and the inner peripheral surface of the cylindrical connecting portion, Since the connection portion between the passage and the joint member is also insulated, the breather tube and its connection portion, that is, the entire blow-by gas passage, are thermally insulated from the outside, and moisture icing can be reliably prevented. In addition, since the heat transfer from the air cleaner side is received by the bowl-shaped portion, the heat receiving area with respect to the air cleaner side is minimized, and cooling of the joint member can be suppressed. According to the second aspect of the present invention, since the breather tube and the cylindrical joint member are made of a material having a low thermal conductivity, the generated ice is easily separated even if a little freezing occurs in the inner tube. Therefore, the prevention of freezing can be further ensured by a synergistic effect with the heat insulating effect of the heat insulating layer.
[Brief description of the drawings]
FIG. 1 is a front perspective view of an in-line four-cylinder engine as an internal combustion engine to which the present invention is applied.
2 is an enlarged sectional view showing a connection portion of a breather tube to an air cleaner in the engine of FIG. 1;
3 is an enlarged cross-sectional view showing a connection portion of the breather tube to the air cleaner as seen in the direction of the line III-III in FIG. 2;
4 is a partially enlarged view of FIG. 3;
FIG. 5 is an enlarged cross-sectional view showing a connection portion of the breather tube to the cylinder head cover side.
[Explanation of symbols]
6 Air Flow Tube 7 Air Cleaner 8 Breather Tube 9 Cylinder Head Cover 11 Inner Tube 12 Outer Tube 13 Heat Insulating Layer 14 Containing Air Layer Cylindrical Connection 15 Joint Member 15a Cylindrical Intrusion 17 Gutter 18a, 18b Annular Convex 19 O Ring 20 Thermal insulation layer

Claims (2)

A blow-by gas processing apparatus for an internal combustion engine configured to return blow-by gas from a crankcase and / or a cylinder head side to a suction passage through a breather tube,
The breather tube, a and the inner tube has a heat insulating layer consisting of air layer while being to pass the blow-by gas, the inserted and the other end to one end to the breather tube between the inner and outer tubes Is connected to the intake passage by a cylindrical joint member inserted into a cylindrical connection portion provided on the intake passage side,
The joint member is provided at a position where the joint member is formed integrally with the joint member so as to form an annular spacer which also serves as a seal on the leading end side of the cylindrical connection portion, and at a position spaced apart from the collar portion in the axial direction. Provided with an O-ring
An internal combustion engine comprising an air layer defined between an outer peripheral surface of the joint member between the flange-shaped portion and the O-ring and an inner peripheral surface of the cylindrical connecting portion . Blow-by gas processing equipment. 2. The blow-by gas processing apparatus for an internal combustion engine according to claim 1, wherein the breather tube and the cylindrical joint member are made of a material having low thermal conductivity .

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