JP2006063884A - Engine blow-by gas recirculation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent clogging of a blow-by gas passage by suppressing freeze of condensed water in blow-by gas. <P>SOLUTION: An engine blow-by gas recirculation device re-circulating blow-by gas of the engine 1 to an intake air passage 26 via a blow-by gas passage 56 is provided with an intake pipe 20 and a blow-by gas recirculation pipe 5 including a blow-by gas recirculation hose 50 and an intake pipe side connection part 52 connecting the hose 50 to the intake pipe 20. The intake pipe side connection part 52 has a double pipe structure which consists of an inner pipe 53 connecting to the blow-by gas recirculation hose 50 and an outer pipe 54 arranged to surround an outer circumference of the inner pipe 53 and connected to an outer circumference wall of the inner pipe 53 at an upstream end and connected to the intake pipe 20 at a downstream end. The inner pipe 53 is arranged in such a manner that a downstream part of an axial line X is oriented downward and a downstream end surface of the inner pipe 53 is constructed in an oblique cut surface 53d opening toward a downstream side of the intake air passage 26. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an engine blow-by gas recirculation device, and more particularly to a connection structure between a blow-by gas recirculation pipe and an intake pipe.

  Conventionally, so-called blow-by gas that leaks into the crankcase from the gap between the piston ring and the cylinder in an engine has contained a large amount of hydrocarbons, so this blow-by gas is forced by using a negative intake pressure using a PCV valve. Blow-by gas recirculation devices that recirculate to the intake passage are known. The blow-by gas recirculation device, for example, guides the blow-by gas in the crankcase to the cylinder head cover and recirculates it into the intake passage through a blow-by gas recirculation pipe that communicates the cylinder head cover and the intake pipe.

  And when the engine equipped with this blow-by gas recirculation device is operated at a low temperature, the blow-by gas recirculation pipe is cooled to a low-temperature atmosphere in the engine room, and water vapor in the blow-by gas condenses, and this blow-by gas recirculation pipe and There is a problem that the condensed water freezes at the connection portion with the intake pipe and the blow-by gas passage in the blow-by gas recirculation pipe is clogged.

  As an improvement measure, there is a blow-by gas recirculation device disclosed in Patent Document 1. In this blow-by gas recirculation device, a union comprising a double-layer heat insulation pipe is provided in an intake pipe, and a blow-by gas recirculation hose is connected to the union. By doing so, the influence of the blow-by gas from the low-temperature atmosphere is reduced at the connecting portion between the blow-by gas recirculation pipe and the intake pipe, and clogging of the blow-by gas passage is suppressed.

In addition, a device that prevents the freezing by providing a heater at the connection between the blow-by gas recirculation pipe and the intake pipe, and special treatment such as fluororesin processing is applied to the inside of the blow-by gas recirculation pipe to make the frozen ice easily peel off There is a device to do.
JP 2002-155720 A

  However, under extremely low temperatures such as in cold regions, the measures against freezing of the blow-by gas recirculation device disclosed in Patent Document 1 may not be sufficient. In other words, when the engine is operated under adverse conditions such as extremely low temperatures, even the blow-by gas recirculation device disclosed in Patent Document 1 may cause the condensed water to freeze and clog the blow-by gas passage. is there. For example, in cold districts and the like, even if the heat insulation structure is adopted as described above, when the ambient temperature around the union in the engine room becomes extremely low, condensed water is generated at the connection portion between the blow-by gas return pipe and the intake pipe. There is a risk of freezing. Further, since the intake air in the intake pipe is also at a very low temperature, the blow-by gas is cooled not only by the low temperature atmosphere but also by the intake air. In consideration of operating the engine in such an environment, a blow-by gas recirculation device that takes measures to further suppress clogging of the blow-by gas passage is required.

  On the other hand, if an attempt is made to prevent clogging of the blow-by gas passage by a device or the like that provides a heater at the connection portion between the blow-by gas recirculation pipe and the intake pipe, the cost increases.

  The present invention has been made in view of such a point, and its object is to effectively suppress freezing of condensed water in blow-by gas without incurring an increase in cost, and It is to reliably prevent clogging of the blow-by gas passage.

  In the present invention, the blow-by gas is hardly affected by the atmosphere in the engine room at the connection portion between the blow-by gas recirculation pipe and the intake pipe, and condensed water condensed from the water vapor contained in the blow-by gas is sucked from the blow-by gas passage. By adopting a structure that easily drops into the passage, clogging due to freezing of the blow-by gas passage is suppressed.

  The first invention is directed to an engine blow-by gas recirculation device that recirculates engine blow-by gas to an intake passage through a blow-by gas passage.

  And a blow-by gas recirculation pipe having an intake pipe that defines the intake passage, a pipe main body portion, and an intake pipe-side connection portion that connects the pipe main body portion to the intake pipe, and that defines the blow-by gas passage. And.

  The intake pipe side connection portion is disposed so as to surround an inner pipe continuous with the pipe body portion and an outer periphery of the inner pipe, and an upstream end thereof is connected to an outer peripheral wall of the inner pipe. On the other hand, the inner end of the inner pipe is arranged with the downstream end of the inner pipe facing downward, and the downstream end face of the inner pipe is the intake pipe. It is comprised by the diagonal cut surface opened toward the downstream of a channel | path.

  In the case of the above configuration, since the axis of the downstream portion of the inner pipe is arranged downward, the condensed water out of the water vapor contained in the blow-by gas flowing through the blow-by gas passage is formed on the inner wall of the inner pipe. Then, it is guided to the downstream end of the inner pipe. In addition, the axis line of the downstream part of the inner pipe does not need to be vertically downward, and may be inclined as long as it faces downward from the horizontal direction.

  The downstream end surface of the inner pipe forms an oblique cut surface that opens toward the downstream side of the intake passage. That is, the downstream end of the inner pipe has a bamboo basket shape. For this reason, the condensed water transmitted through the inner wall of the inner pipe is collected at the most downstream end of the oblique cut surface, that is, at the front end of the bamboo basket shape. In this way, by condensing condensed water that travels along the inner wall of the inner pipe at one location at the open end, the condensed water is promoted to grow into water droplets of a size that naturally falls by its own weight, and the condensed water is frozen. It can be quickly dropped into the intake passage before Even if the condensed water freezes at the open end of the inner pipe, the frozen ice that adheres to the open end of the inner pipe is concentrated at the most downstream end of the oblique cut surface, so that the frozen ice is in one place. As a result of the concentration, it becomes difficult to completely block the blow-by gas passage, and the falling of frozen ice can be promoted. Further, since the oblique cut surface opens toward the downstream side of the intake passage, blow-by gas and condensed water at the downstream end of the oblique cut surface flow into the intake passage along the flow of intake air in the intake passage. And it becomes easy to fall.

  Further, by adopting a double tube structure in which the outer tube is provided outside the inner tube, the inner tube does not directly touch the atmosphere in the engine room. For this reason, even if the engine is operated at an extremely low temperature and the ambient temperature in the engine room is an extremely low temperature, the condensed water collected at the downstream end of the oblique cut surface is difficult to freeze. Further, by adopting a double pipe structure, the position of the downstream end portion of the inner pipe can be arbitrarily set in a space surrounded by the intake pipe and the outer pipe.

  According to a second aspect, in the first aspect, the downstream end of the inner pipe is disposed deeper on the upstream side of the blow-by gas passage than the boundary surface between the blow-by gas passage and the intake passage. .

  In the case of the above configuration, the place where the inner pipe is recessed deeper in the upstream of the blow-by gas passage than the boundary surface between the intake passage and the blow-by gas passage, that is, the place where the intake air does not directly hit the downstream end of the inner pipe An inner tube can be arranged. As a result, it is difficult for the intake air to directly hit the condensed water collected at the downstream end of the inner pipe, so that the freezing of the condensed water at the downstream end of the inner pipe can be further suppressed.

  According to a third invention, in the first or second invention, the outer pipe is integrally formed with the inner pipe and a resin, the intake pipe is made of resin, and a downstream end of the outer pipe is connected to the outer pipe. The downstream end of the outer tube and the opening are joined by thermal welding, and the downstream end of the inner tube is more than the welding surface of the outer tube and the opening. It is assumed that it is disposed behind the blowby gas passage.

  In the case of the above configuration, the sealing performance is improved by adopting a heat welding structure by resin molding, as compared with a structure in which the outer tube and the opening are fixed by bolts or metal rings.

  Further, when the outer pipe and the opening are welded by hot plate welding, the downstream end of the inner pipe is disposed deeper on the upstream side of the blow-by gas passage than the welding surface of the outer pipe and the opening. It is not necessary to provide a hole for avoiding interference with the inner pipe in the welding plate. As a result, the welding plate can be easily installed and removed.

  In a fourth aspect based on the first to third aspects, the intake pipe side connecting portion is connected to the intake pipe from substantially above.

  In the case of the above configuration, the condensed water collected at the downstream end of the inner pipe easily falls into the intake passage.

  According to a fifth aspect of the present invention, in the first to fourth aspects, the engine is mounted horizontally with the exhaust port facing the rear of the vehicle body and the intake port facing the front of the vehicle body at the front of the vehicle body. A turbocharger is disposed on the rear side, and one end of the blow-by gas recirculation pipe is connected to the cylinder head cover, and the other end is connected to the turbocharger at the inflow side intake pipe. Shall be connected in the vicinity of

  In the case of the above configuration, the ambient temperature on the rear side of the vehicle body of the horizontally placed engine of the rear exhaust is relatively high in the engine room. In addition, a turbocharger is provided on the rear side of the vehicle body of the engine, and the turbocharger has a high temperature, so that the ambient temperature on the rear side of the engine body becomes higher. That is, by connecting the other end of the blow-by gas recirculation pipe to the inflow side intake pipe of the turbocharger on the rear side of the vehicle body, the atmosphere around the inner pipe and the outer pipe is changed to the front of the engine vehicle in the engine room. Compared to the atmosphere or the like, the temperature becomes relatively high, and even when the engine is operated at an extremely low temperature, the condensed water gathering at the downstream end of the oblique cut surface of the inner pipe is more difficult to freeze.

  According to the present invention, the downstream end portion of the inner pipe is not in direct contact with the atmosphere in the engine room by the double pipe structure, and the condensed water in the blow-by gas transmitted through the inner wall of the inner pipe is slanted cut surface. It is possible to prevent the condensed water from freezing at the downstream end portion of the blow-by gas reflux pipe by facilitating the dropping of the condensed water by collecting at the downstream end. Furthermore, even if the condensed water freezes at the downstream end of the blow-by gas recirculation pipe, by forming an oblique cut surface at the downstream end of the inner pipe, the accumulation of frozen ice is concentrated in one place. Thus, the blow-by gas passage can be prevented from being completely blocked, and the frozen ice can be easily removed. As a result, it is possible to prevent clogging of the blow-by gas recirculation pipe while suppressing costs.

  According to the second aspect of the invention, since the downstream end of the inner pipe is difficult to directly hit the intake air, it is possible to more effectively suppress the freezing of condensed water, and even if frozen ice accumulates on the inner pipe, the accumulation amount is reduced. Can be made.

  According to the third aspect of the invention, since the connecting portion between the outer tube and the opening is performed by resin thermal welding, the sealing performance of the connecting portion can be improved. Furthermore, the workability | operativity at the time of welding can be improved by making the downstream end of an inner pipe back in the upstream of a blow-by gas path rather than a welding surface.

  According to the fourth aspect, the fall of condensed water can be promoted by connecting the outer pipe to the intake pipe from substantially above.

  According to the fifth aspect, the freezing of condensed water that collects at the downstream end of the inner pipe is further suppressed by disposing the intake pipe side connecting portion in a place where the ambient temperature in the engine room is relatively high. Can do.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic diagram of a blow-by gas recirculation device for an engine according to the present embodiment. Reference numeral 1 is an in-line four-cylinder diesel engine mounted in the engine room R, reference numeral 2 is an intake system thereof, reference numeral 3 is an exhaust system thereof, and reference numeral 6 is disposed in front of the engine 1 in the engine room R. Is a radiator.

  The engine 1 is mounted horizontally in the engine room R so that an intake port opens on the front side surface of the vehicle and an exhaust port opens on the rear side surface of the vehicle. The upper part of the engine 1 is covered with a cylinder head cover 11. The so-called blow-by gas that leaks into the crankcase from the gap between the cylinder 12 and the piston ring (not shown) is guided into the cylinder head cover 11 through a passage provided in the cylinder block and the cylinder head. The blow-by gas guided to the cylinder head cover 11 is returned to the intake system 2 by a blow-by gas return pipe 5 described later.

  The intake system 2 includes an intake pipe 20. In the intake pipe 20, an air cleaner 21, a blower 41 of the turbocharger 4, an intercooler 22, and an intake throttle valve 23 are provided in order from the upstream side along the flow of intake air (in the direction of the arrow in the drawing). The intake pipe 20 is attached to the vehicle front side surface of the engine 1 via an intake manifold 24 continuous with the intake port. An intake passage 26 is defined in the intake pipe 20. Further, in the intake pipe 20, an opening as an opening for connecting an outer pipe 54 of an intake pipe side connection portion 52 described later is provided in the vicinity of the blower 41 of the inflow side intake pipe 20 a located between the air cleaner 21 and the blower 41. A cylindrical portion 25 is formed. The opening cylinder portion 25 is connected from substantially vertically above so as to be orthogonal to the tube axis of the intake pipe 20, and is open substantially vertically upward. Moreover, the opening cylinder part 25 has the upstream end surface 25a perpendicular | vertical with respect to a cylinder axis (refer FIG. 2 and 3). The intake pipe 20 and the opening cylinder part 25 are integrally formed of resin.

  The exhaust system 3 includes an exhaust pipe 30. The exhaust pipe 30 is attached to the vehicle rear side surface of the engine 1 via an exhaust manifold 31 continuous with the exhaust port. The exhaust pipe 30 is upstream along the flow of exhaust (arrow in the figure). In order from the side, a turbine 42 of the turbocharger 4 and a diesel particulate filter 32 that collects particulates in the exhaust gas are interposed.

  The blow-by gas recirculation pipe 5 includes a blow-by gas recirculation hose 50 as a blow-by gas recirculation pipe main body, a head cover side connection portion 51 that connects the blow-by gas recirculation hose 50 and the cylinder head cover 11, and the blow-by gas recirculation hose 50 and the intake pipe 20. And an intake pipe side connecting portion 52 for connecting the two.

  A blow-by gas passage 56 is formed by the head cover side connection portion 51, the passage in the blow-by gas recirculation hose 50 and the intake pipe side connection portion 52, and the passage in the opening cylinder portion 25.

  The head cover side connecting portion 51 is provided on the vehicle rear side of the cylinder head cover 11 at a substantially central position in the cylinder row direction.

  As shown in FIG. 1, the intake pipe side connecting portion 52 is provided in the vicinity of the blower 41 of the inflow side intake pipe 20 a located between the air cleaner 21 and the blower 41 in the intake pipe 20. Further, the turbocharger 4 is disposed on the vehicle rear side of the engine 1, and the intake pipe side connecting portion 52 is located in the engine room R at the vehicle rear side than the engine 1. As shown in FIG. 2, the intake pipe side connection portion 52 is disposed so as to surround the inner pipe 53 to which the blow-by gas recirculation hose 50 is connected, the outer periphery of the inner pipe 53, and the blow-by gas passage 56 and the intake pipe. And an outer tube 54 communicating with the passage 26.

  The inner pipe 53 is made of resin, and as shown in FIG. 2, the upstream portion 53a is located on the upstream side and the axis X is inclined, and the axis X is located in the vertical direction on the downstream side. And a bent portion 53b that connects the upstream portion 53a and the downstream portion 53c, and has a generally square shape. The blow-by gas recirculation hose 50 is fitted into the upstream portion 53a. Further, the inner pipe 53 has a so-called bamboo basket shape in which an oblique cut surface 53d that opens toward the downstream side of the intake passage 26 is formed at the downstream end thereof.

  The outer tube 54 is integrally formed with the inner tube 53 with resin. As shown in FIG. 2, the outer tube 54 has an upstream end connected to the outer peripheral wall of the downstream portion 53 c of the inner tube 53, and the upstream portion 54 a has a diameter larger than that of the inner tube 53. Further, the outer tube 54 has a downstream portion 54b continuous with the upstream portion 54a extending downward without changing the inner diameter and the outer diameter with the axis X of the downstream portion 53c of the inner tube 53 as an axis, and the downstream end thereof is It is connected to the opening cylinder part 25 of the intake pipe 20. The downstream end surface 54 c of the outer tube 54 is a surface perpendicular to the axial center of the outer tube 54 (which coincides with the axis X of the downstream portion 53 c of the inner tube 53), and is blowby gas more than the downstream end of the inner tube 53. Located downstream of the passage 56. The outer cylindrical portion 25 has the same outer diameter and inner diameter as the outer diameter and inner diameter of the downstream portion 54 b of the outer tube 54. The outer pipe 54 is connected to the intake pipe 20 by the opening cylinder portion 25.

  Further, the downstream end face 54c of the outer tube 54 is thermally welded to the upstream end face 25a of the opening cylindrical portion 25 by hot plate welding. Specifically, the welding plate is sandwiched between the downstream end surface 54c of the outer tube 54 and the upstream end surface 25a of the opening cylinder portion 25, and after both members are sufficiently heated, the welding plate is pulled out to weld both members.

  As described above, the intake pipe side connection portion 52 has a double pipe structure including the inner pipe 53 and the outer pipe 54. As described above, the downstream end of the inner tube 53 is blow-by gas more than the weld surface Z between the outer tube 54 and the open tube portion 25, which is composed of the downstream end surface 54 c of the outer tube 54 and the upstream end surface 25 a of the open tube portion 25. It is disposed behind the passage 56 in the upstream. Therefore, the downstream end of the inner pipe 53 is disposed deeper on the upstream side of the blow-by gas passage 56 than the boundary surface Y (two-dot chain line in FIG. 2) between the blow-by gas passage 56 and the intake passage 26. Moreover, since the opening cylinder part 25 is located substantially directly on the cross-sectional view of the intake pipe 20 and opens vertically upward, the outer pipe 54 is connected to the pipe axis of the intake pipe 20 as shown in FIG. They are connected from substantially vertically above so as to be orthogonal to each other.

  The blowby gas recirculation hose 50 connected to the head cover side connecting portion 51 and the intake pipe side connecting portion 52 is located on the vehicle rear side of the engine 1.

  Next, the flow of blow-by gas will be described.

  The blow-by gas that leaks into the crankcase from the gap between the cylinder 12 and the piston ring is guided into the cylinder head cover 11 through a passage (not shown) provided in the cylinder block and the cylinder head. The blowby gas guided into the cylinder head cover 11 is guided to the intake pipe 20 via the blowby gas recirculation hose 50. The blow-by gas sucked into the intake pipe 20 in the upstream portion of the blower 41 is mixed with the intake air and sent into the combustion chamber.

  Here, a case where the engine 1 is operated at an extremely low temperature such as a cold region will be considered. Under such conditions, the temperature of the intake air is close to the outside air temperature and extremely low (for example, below the freezing point). Further, the ambient temperature in the engine room R is also affected by the outside air temperature, and is lower than that in the case where the engine room R is used under a warm condition. On the other hand, the blow-by gas in the cylinder head cover 11 is heated by the combustion of the engine 1 and has a high temperature. Therefore, the blow-by gas is cooled while flowing from the cylinder head cover 11 through the blow-by gas recirculation hose 50 to the intake pipe 20. For example, at a very low temperature, the temperature of the blow-by gas decreases by several tens of degrees Celsius while flowing from the cylinder head cover 11 to the intake pipe 20. As a result, the water vapor contained in the blow-by gas condenses into water, and flows through the blow-by gas passage 56 to the intake pipe 20.

  The condensed water finally flows along the inner wall of the inner pipe 53 and flows into the intake passage 26. Here, since the axis X of the downstream portion 53c of the inner pipe 53 is disposed vertically downward, the condensed water is promoted to flow into the intake passage 26. In addition, since the downstream end of the inner pipe 53 is an oblique cut surface 53 d that opens toward the downstream side of the intake passage 26, the condensed water that travels along the inner wall of the inner pipe 53 is absorbed by the bamboo pipe-shaped inner pipe 53. It gathers at the tip and grows into large water droplets, and drops into the intake passage 26 at an early stage. Further, since the oblique cut surface 53d faces the downstream side of the intake passage 26, the blow-by gas easily flows toward the downstream side of the intake passage 26, and the condensed water collected at the tip of the bamboo basket shape is also in the intake passage 26. It is easy to drop off. For this reason, the condensed water is unlikely to stay at the downstream end of the inner pipe 53, so that the blow-by gas passage 56 is less likely to be clogged due to freezing.

  Since the downstream end portion of the inner pipe 53 is covered with the outer pipe 54, the downstream end portion of the inner pipe 53 does not directly touch the low-temperature atmosphere temperature in the engine room R, and the downstream end portion of the inner pipe 53 does not touch the downstream end of the inner pipe 53. The condensed water that collects is not easily affected by the extremely low temperature in the engine room R.

  Even if the condensed water freezes at the downstream end of the inner pipe 53, the frozen ice collects at the tip of the bamboo basket shape, so that the blow-by gas passage 56 is hardly completely clogged. Moreover, since the frozen ice is concentrated in one place, the falling of the frozen ice into the intake passage 26 is promoted.

  Therefore, in the above embodiment, by forming the oblique cut surface 53d at the downstream end of the inner pipe 53, the condensed water in the blow-by gas transmitted through the inner wall of the inner pipe 53 is quickly dropped into the intake passage 26. At the same time, the intake pipe side connecting portion 52 has a double pipe structure composed of the inner pipe 53 and the outer pipe 54, thereby preventing the downstream end portion of the inner pipe 53 from coming into direct contact with the ambient temperature in the engine room R. Therefore, clogging due to freezing of the blow-by gas passage 56 can be suppressed.

  Further, the intake pipe side connecting portion 52 has a double pipe structure composed of the inner pipe 53 and the outer pipe 54, so that the downstream end of the inner pipe 53 is located more than the boundary surface Y between the blowby gas passage 56 and the intake passage 26. Since it can be disposed behind the blow-by gas passage 56, intake air can be prevented from directly hitting the condensed water collected at the downstream end of the inner pipe 53, and freezing of the condensed water can be further suppressed. .

  Further, the portion near the blower 41 of the inflow side intake pipe 20 a where the intake pipe side connection portion 52 is provided is located behind the vehicle of the engine 1. In the engine room R in which an air flow from the front of the vehicle to the rear of the vehicle is generated by the radiator 6, the rear side of the engine 1 is a place where heat is likely to stay, and the turbocharger 4 is at a high temperature. Even if the atmospheric temperature in R is extremely low as a whole, the ambient temperature around the intake pipe side connecting portion 52 is relatively high. For this reason, it is possible to prevent the condensed water gathering at the downstream end of the inner pipe 53 from freezing. The blow-by gas recirculation hose 50 extends from the rear side of the cylinder head cover 11 to the rear side of the vehicle and is connected to the intake pipe side connection portion 52. The blow-by gas recirculation hose 50 itself also has a relatively high ambient temperature. Therefore, the temperature drop of the blow-by gas flowing from the cylinder head cover 11 to the intake pipe 20 via the blow-by gas recirculation pipe 5 can be suppressed as much as possible.

  Further, as described above, the downstream end of the inner pipe 53 is deeper on the upstream side of the blow-by gas passage 56 than the welding surface Z. Therefore, in the hot plate welding between the outer pipe 54 and the opening cylinder portion 25, During installation and removal, the inner pipe 53 does not interfere with the welding plate, and workability during welding is improved. Further, compared to a structure in which the outer pipe 54 is welded directly to the pipe wall of the intake pipe 20, the outer pipe 54 is welded to the opening cylinder portion 25 protruding from the intake pipe 20. The upstream end face 25a) of the cylindrical portion 25 can be formed flat, and the welding operation can be facilitated.

<< Other Embodiments >>
The present invention may be configured as follows with respect to the above embodiment.

  That is, in the above-described embodiment, the blow-by gas recirculation hose 50 and the intake pipe side connection portion 52 are configured separately, but the present invention is not limited to this and may be integrally formed.

  In the above embodiment, the blow-by gas is guided into the cylinder head cover. However, the present invention is not limited to this. After the blow-by gas is guided to the oil separator chamber provided in the cylinder block, the blow-by gas is returned to the intake system. For example, the blow-by gas leaked into the crank chamber may be finally returned to the intake system 2. In such a case, the connection part on the engine side of the blow-by gas recirculation pipe is provided not on the cylinder head cover 11 but on the cylinder block or the like.

  Further, the downstream portion 53c of the inner pipe 53 is disposed so that its axis X is vertically downward, but is not limited thereto. Even if the axis X is inclined, it only needs to face downward. With such a configuration, the condensed water in the blow-by gas transmitted through the inner wall of the inner pipe 53 is guided to the intake passage 26 without stagnation in the middle of the inner pipe 53.

  Similarly, the opening cylinder portion 25 is not limited to a configuration that is connected substantially vertically from above so as to be orthogonal to the tube axis of the intake pipe 20. Any position where condensed water that drops from the downstream end of the inner pipe 53 falls into the intake passage 26 may be used.

  In the above embodiment, the opening tube portion 25 is provided in the intake pipe 20 and the opening tube portion 25 and the outer tube 54 are welded. However, the outer tube 54 may be welded directly to the intake tube 20. In such a case, an opening for connecting the outer pipe 54 to the intake pipe 20 is formed in the intake pipe 20, and the blow-by gas passage 56 includes the head cover side connection part 51, the blow-by gas recirculation hose 50, and the intake pipe side connection part. Formed by a passage in 52. Further, the connection between the outer pipe 54 and the intake pipe 20 or the opening cylinder portion 25 is not limited to welding. For example, bolt fastening or fastening with a metal ring may be used.

It is a mimetic diagram showing a blowby gas recirculation device concerning an embodiment of the present invention. It is sectional drawing which shows the intake pipe side connection part of a blowby gas recirculation pipe. It is a perspective view which shows the external appearance of a blowby gas recirculation pipe.

Explanation of symbols

1 Engine 11 Cylinder head cover 20 Intake pipe 20a Inlet side intake pipe 26 Intake passage 4 Turbocharger 5 Blow-by gas recirculation pipe 50 Blow-by gas recirculation hose (pipe main body)
52 Intake pipe side connection part 53 Inner pipe 53a Inclined cut surface 53c Downstream part 54 Outer pipe 56 Blow-by gas passage X Inner tube axis Y Boundary surface Z between the blow-by gas passage and the intake passage

Claims (5)

An engine blow-by gas recirculation device that recirculates engine blow-by gas to an intake passage through a blow-by gas passage,
An intake pipe defining the intake passage;
A blow body gas recirculation pipe having a pipe body portion and an intake pipe side connection portion for connecting the pipe body portion to the intake pipe and defining the blow-by gas passage;
The intake pipe side connecting portion is arranged so as to surround the inner pipe continuous with the pipe main body portion and the outer periphery of the inner pipe, and its upstream end is connected to the outer peripheral wall of the inner pipe, A double pipe structure consisting of an outer pipe whose downstream end is connected to the intake pipe,
The inner pipe is arranged with the downstream axial line facing downward, and the downstream end surface of the inner pipe is configured as an oblique cut surface opening toward the downstream side of the intake passage. Reflux apparatus. The blowby gas recirculation device for an engine according to claim 1,
The blow-by gas recirculation device characterized in that the downstream end of the inner pipe is disposed deeper on the upstream side of the blow-by gas passage than the boundary surface between the blow-by gas passage and the intake passage. The blow-by gas recirculation device for an engine according to claim 1 or 2,
The outer tube is integrally formed with the inner tube and resin,
The intake pipe is made of resin and has an opening to which a downstream end of the outer pipe is connected;
The downstream end of the outer tube and the opening are joined by heat welding,
The blow-by gas recirculation device according to claim 1, wherein the downstream end of the inner pipe is disposed deeper on the upstream side of the blow-by gas passage than the welding surface between the outer pipe and the opening. The blowby gas recirculation device for an engine according to any one of claims 1 to 3,
The blow-by gas recirculation device, wherein the intake pipe side connecting portion is connected to the intake pipe from substantially above. The blow-by gas recirculation device for an engine according to any one of claims 1 to 4,
The engine is mounted horizontally with the exhaust port facing the rear of the vehicle and the intake port facing the front of the vehicle at the front of the vehicle,
A turbocharger is disposed on the rear side of the engine body,
One end of the blow-by gas recirculation pipe is connected to the cylinder head cover, and the other end is connected to the vicinity of the turbocharger in the intake pipe of the turbocharger. apparatus.

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