JP6225885B2 - Blowby gas recirculation system - Google Patents

Description

  The present invention relates to a blow-by gas recirculation device in an engine with a supercharger.

  Conventionally, blow-by gas discharged from the engine body has been returned to the intake passage upstream of the turbocharger (upstream in the direction of intake air flow) through the blow-by gas piping, and joined to fresh air for combustion. Has been done. In this case, dew condensation water may be generated in the blow-by gas piping. If this condensed water drops into the intake passage and accumulates at the bottom of the passage, in cold districts, the condensed water is cooled by low-temperature intake and becomes ice lump, which is sucked into the supercharger and damages the compressor. Can be considered.

  Patent Document 1 discloses a blow-by gas recirculation device for solving the above problems. This device includes a metal sealing gasket interposed between a supercharger (compressor) and an intake passage, and a metal receiving plate that is fixed to the gasket and receives condensed water dripping into the intake passage. And. According to this configuration, since heat is transmitted from the supercharger whose temperature has been increased to the receiving plate via the sealing gasket, the formation of ice clumps of condensed water dripping on the receiving plate is suppressed.

JP 2010-255545 A

  However, in addition to freezing of the condensed water dripped in the intake passage, in cold regions, the condensed water freezes in the blow-by gas introduction port portion (hereinafter simply referred to as the gas introduction portion) formed in the intake passage. If the gas inlet port is blocked, the reflux of blow-by gas may be hindered. Moreover, there is a possibility that ice blocks adhering to the gas introduction port drop off and are sucked into the supercharger to damage the compressor. The blow-by gas recirculation apparatus disclosed in Patent Document 1 cannot solve such a problem.

Meanwhile, vehicles such as automobiles are required to be equipped with various OBDs (On Board Diagnostics System / self-fault diagnosis device). The same applies to the blow-by gas recirculation device. For example, as described in detail later in “DETAILED DESCRIPTION OF THE INVENTION”, each of an air flow sensor installed in an intake passage and an O ₂ sensor installed in an exhaust passage. Based on changes in detection information, it is considered to minimize blow-by gas discharge by detecting blow-by gas piping abnormalities, specifically, forgetting to install or removing blow-by gas piping during maintenance. Yes. That is, if the gas inlet port is opened due to forgetting to attach the blow-by gas pipe, intake air leaks through the gas inlet port, and the relationship between the detection information changes. Can be detected. In this case, in order to ensure the detection accuracy, it is necessary to set the diameter of the gas inlet port as large as possible so that the detection information changes significantly when intake air leaks. In this case, however, the diameter of the blow-by gas pipe increases with the expansion of the diameter of the gas introduction port, making it difficult to operate, which may affect the layout of the engine as a whole. In addition, as the diameter of the gas inlet is increased, there is a problem that the freezing area increases and the risk of the ice block falling off increases. Therefore, it is necessary to solve these points in the blow-by gas recirculation apparatus.

  The present invention has been made in view of the circumstances as described above, and effectively solves the problem when the OBD is mounted, that is, the diameter of the blow-by gas pipe is increased, and it is effective that the blow-by gas inlet is frozen. It is an object of the present invention to provide a blow-by gas recirculation device that can be suppressed.

In order to solve the above-mentioned problems, the present invention is a blow-by gas recirculation device for an engine with a supercharger, and includes a compressor housing including a housing body and an intake air inlet pipe portion provided integrally therewith. And a blow-by gas pipe connected to the intake air introduction pipe part and merging blow-by gas discharged from the engine main body with the intake air in the intake air introduction pipe part, and the intake air introduction pipe part is provided on the circumferential surface The blow-by gas pipe has a peripheral wall part in which an opening for introducing a blow-by gas is formed, and the blow-by gas pipe is provided at the end of the pipe main body and is detachably fixed to the intake air inlet pipe part. The connecting portion is fixed to the peripheral wall portion in a state in which the opening portion is closed, and is more eccentric than the opening portion at a position eccentric from the center of the opening portion toward the housing body side. In which it is provided with a communication passage for communicating the have again inner diameter and the pipe body and the intake air introduction pipe portion.

  In this apparatus, the blow-by gas merges with the intake air in the intake air introduction pipe section at the position of the opening through the communication body of the connection section from the pipe body of the blow-by gas pipe. According to this apparatus, when the turbocharger operates to raise the temperature, heat is transferred from the housing main body of the compressor housing to the connecting portion via the intake air inlet pipe portion, and the ambient temperature of the communication path increases. Therefore, the dew condensation water generated in the blow-by gas pipe is prevented from icing in the blow-by gas inlet port, that is, the communication path, to the intake air inlet pipe. Further, according to this apparatus, since the blow-by gas is introduced into the intake introduction pipe portion through the communication passage, the diameter of the opening formed in the peripheral wall portion of the intake introduction pipe portion is relatively large, but the communication is performed. The diameter of the passage itself can be kept small. That is, while applying a pipe body having a small diameter, when the blow-by gas pipe is not connected, the intake inlet pipe part can be largely opened through the opening. In addition, since the communication path is provided at a position that is eccentric from the center of the opening toward the housing body, the condensed water in the blow-by gas freezes in the communication path regardless of the size of the opening. Can be effectively suppressed. Therefore, it is possible to effectively prevent the blow-by gas introduction port portion from icing while solving the problem of the OBD mounting, that is, increasing the diameter of the blow-by gas piping.

  In this blow-by gas recirculation device, the compressor housing may be integrated so that heat can be transferred by combining a separately formed housing body and an intake air inlet pipe portion. It is preferable that the housing main body and the intake air introduction pipe portion are integrally formed of the same metal material.

  According to this configuration, the heat generated by the operation of the supercharger is more smoothly transmitted from the housing body to the intake air inlet pipe portion. Therefore, icing in the communication path is more effectively suppressed.

  Further, in the blow-by gas recirculation device, the connecting portion has a fitting portion that is detachably fitted to the opening and fills a portion of the space inside the opening other than the communication path. It is suitable.

  According to this configuration, the opening prevents the concave portion from being formed on the inner peripheral surface of the intake pipe portion. Therefore, it is suppressed that the flow of intake air is disturbed by the concave portion and the supercharging performance is reduced or abnormal noise is generated. Moreover, it is prevented that the dew condensation water in the blow-by gas introduced into the intake air introduction pipe part through the communication path freezes on the inner peripheral surface of the opening.

  In this case, in the case where the intake introduction pipe portion has an inner peripheral surface having a circular cross section, a surface of the fitting portion that faces the inside of the intake introduction pipe portion is along the inner peripheral surface of the intake introduction pipe portion. It is preferable to have a curved surface that is flush with the inner peripheral surface. “Circular” means including both a perfect circle and an ellipse.

  According to this configuration, the deterioration of the supercharging performance and the generation of abnormal noise due to the turbulence of the intake air as described above, and the freezing of condensed water to the opening are further suppressed to a high degree.

  Further, in the blow-by gas recirculation device, a groove portion that is recessed toward the opposite housing body side and extends in a direction parallel to the center line of the opening is formed on the side surface of the fitting portion on the housing body side. It is preferable that at least a part of the communication path is formed by a space surrounded by an inner surface of the groove and an inner peripheral surface of the opening.

  According to this configuration, the blow-by gas flowing through the communication passage can directly contact the intake pipe portion, so heat input to the blow-by gas is promoted, and the condensed water in the blow-by gas is frozen. Is more highly suppressed.

  In the above blow-by gas recirculation device, it is preferable that the connecting portion is formed of a material having a lower thermal conductivity than the intake air introduction pipe portion.

According to this configuration, it is advantageous in suppressing heat transfer from the connecting portion to the intake air inlet pipe portion, particularly heat transfer to the portion upstream of the opening that is cooled by the intake air. Thereby, it becomes possible to keep the temperature of a connection part, especially the temperature of the communicating path vicinity higher, and it is suppressed more highly that the dew condensation water in blow-by gas freezes.
Note that a blow-by gas recirculation device for a supercharged engine according to another aspect of the present invention includes a housing body and a compressor that includes an intake air inlet pipe portion that is provided integrally therewith and has an inner peripheral surface with a circular cross section. A turbocharger having a housing; and a blow-by gas pipe connected to the intake air introduction pipe part to merge blow-by gas discharged from the engine body with the intake air in the intake air introduction pipe part, and the intake air introduction pipe part Has a peripheral wall part in which an opening for introducing a blow-by gas is formed, and the blow-by gas pipe is provided at the end of the pipe main body and the pipe main body and is detachably fixed to the intake air inlet pipe part. A connecting portion, and the connecting portion is fixed to the peripheral wall portion in a state in which the opening portion is closed, and the opening portion is at a position eccentric to the housing body side from the center of the opening portion. A communication passage that has a smaller inner diameter and communicates between the pipe body and the intake air introduction pipe portion, and is detachably fitted to the opening portion, and the communication passage in the space inside the opening portion. A fitting portion that fills the other portion of the fitting portion, and a surface of the fitting portion that faces the inside of the intake introduction pipe portion is a curved surface along an inner peripheral surface of the intake introduction pipe portion. It has a shape that is flush with the inner peripheral surface.
Further, a blow-by gas recirculation device for a supercharged engine according to still another aspect of the present invention is a supercharger having a compressor housing including a housing body and an intake air introduction pipe portion provided integrally therewith, A blow-by gas pipe connected to the intake air introduction pipe part for merging blow-by gas discharged from the engine main body with the intake air in the intake air introduction pipe part, wherein the intake air introduction pipe part is an opening for introducing the blow-by gas The blow-by gas pipe includes a pipe main body and a connecting part that is provided at an end of the pipe main body and is detachably fixed to the intake introduction pipe part. The portion is fixed to the peripheral wall portion in a state in which the opening is closed, and has an inner diameter smaller than the opening at a position eccentric from the center of the opening toward the housing body. And a communication passage that allows the piping main body and the intake air introduction pipe portion to communicate with each other, and is fitted so as to be removably fitted into the opening portion so as to fill a portion inside the opening portion other than the communication passage. A groove portion that is recessed toward the anti-housing main body side and that extends in a direction parallel to the center line of the opening is formed on the side surface of the fitting portion on the housing main body side. At least a part is formed by a space surrounded by the inner surface of the groove and the inner peripheral surface of the opening.

  As described above, according to the blow-by gas recirculation device of the present invention, it is possible to effectively prevent the blow-by gas inlet port from icing while solving the problem of the OBD mounting, that is, increasing the diameter of the blow-by gas pipe. Can be suppressed.

1 is a diagram illustrating an overall configuration of an engine with a turbocharger to which the present invention is applied. It is a perspective view which shows a turbocharger. It is sectional drawing of the said turbocharger. It is a perspective view which shows the said turbocharger in the state which removed the blowby gas piping. It is a perspective view which shows the said turbocharger. It is a perspective view (state seen from the front side) of the connection member of blowby gas piping. It is a perspective view (state seen from the back side) of the said connection member.

  Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

(Entire engine configuration)
FIG. 1 shows a supercharged engine according to an embodiment of the present invention. The engine shown in the figure is a 4-cycle spark ignition type multi-cylinder engine mounted on a vehicle as a power source for traveling. Specifically, this engine is generated by an in-line four-cylinder engine body 1 having four cylinders 2 arranged in a row, an intake passage 10 for introducing air into the engine body 1, and the engine body 1. An exhaust passage 30 for discharging exhaust gas and a supercharger 20 are provided. In this embodiment, the supercharger 20 is the turbocharger 20 that is driven by the energy of the exhaust gas. However, a supercharger other than the turbocharger may be applied.

  The engine body 1 includes a cylinder block having a cylinder 2, a cylinder head disposed on the cylinder block, an oil pan disposed on the lower side of the cylinder block, a cylinder head cover that covers an upper portion of the cylinder head, and the like.

  A piston is inserted into each cylinder 2 of the engine body 1 so as to be slidable in a reciprocating manner. A combustion mixture of fuel and air burns in a combustion chamber defined above each piston. The piston reciprocates due to the expansion energy generated by, and the reciprocating motion of the piston is converted into the rotational motion of the crankshaft and output.

The intake passage 10 includes four independent intake passages 11 communicating with the intake port of each cylinder 2, and a surge tank 12 provided in common on the upstream side (upstream side in the intake air flow direction) of each independent intake passage 11 A single tubular downstream intake pipe 13 provided on the upstream side of the surge tank 12 and a single tubular upstream intake pipe 16 provided on the upstream side of the downstream intake pipe 13 are included.

The downstream intake pipe 13 is provided with a throttle valve 14 for adjusting the intake air amount and an intercooler 15 for cooling the air compressed by the turbocharger 20. The upstream side intake pipe 16 is provided with an air cleaner 17 and an air flow sensor SN1 for detecting the intake air amount in that order from the upstream side.

  The exhaust passage 30 includes four independent exhaust passages 31 communicating with the exhaust ports of the cylinders 2 and an exhaust collecting portion 32 in which the downstream end portions (end portions on the downstream side in the exhaust gas flow direction) of the independent exhaust passages 31 are gathered. And a single tubular exhaust pipe 33 provided on the downstream side of the exhaust collecting portion 32.

The exhaust pipe 33 is provided with a catalytic converter 35 including a catalyst such as a three-way catalyst, a silencer (not shown), and the like, and an O ₂ sensor SN2 for detecting oxygen (O ₂ ) in the exhaust gas. Is provided.

The turbocharger 20 includes a turbine housing 21 provided immediately downstream of the exhaust collecting portion 32 of the exhaust passage 30 (between the exhaust collecting portion 32 and the exhaust pipe 33), and a turbine disposed in the turbine housing 21. 22, a compressor housing 23 disposed immediately upstream of the downstream side intake pipe 13 of the intake passage 10 (between the downstream side intake pipe 13 and the upstream side intake pipe 16), and the compressor housing 23. The compressor 24 and a connecting shaft 25 that connects the turbine 22 and the compressor 24 to each other are provided. When the exhaust gas is discharged from each cylinder 2 of the engine body 1 during the operation of the engine, the exhaust gas flows into the turbine housing 21 of the turbocharger 20 through the independent exhaust passage 31 and the like, so that the turbine 22 exhausts. Receiving gas energy and rotating at high speed. Further, when the compressor 24 connected to the turbine 22 via the connecting shaft 25 is driven at the same rotational speed as the turbine 22, the intake air passing through the intake pipes 13 and 16 is pressurized, and the engine body 1 Pumped to each cylinder 2.

  The compressor housing 23 and the engine body 1 of the turbocharger 20 are connected to each other via a blow-by gas pipe 40. The blow-by gas pipe 40 is a passage for deriving blow-by gas generated in the engine body 1 and recirculating (joining) it to fresh air. One end of the blow-by gas pipe 40 is connected to the cylinder head cover of the engine body 1, and the other end is connected to a later-described intake air inlet pipe portion 23 b of the compressor housing 23 as will be described in detail later.

  The exhaust passage 30 and the intake passage 10 are connected to each other via the EGR passage 50. The EGR passage 50 is a passage for performing so-called exhaust gas recirculation, in which a part of the exhaust gas discharged from the engine body 1 is returned to the intake system. One end of the EGR passage 50 is connected to the exhaust passage 30 upstream of the turbine 22, more specifically, the exhaust collecting portion 32, and the other end of the EGR passage 50 is connected to the intake passage 10 downstream of the compressor 24, More specifically, it is connected to the surge tank 12.

  The EGR passage 50 is provided with an EGR cooler 52 for cooling EGR gas (exhaust gas returned to the intake system) and an EGR valve 53 for controlling the flow rate of the EGR gas passing through the EGR passage 50. .

Reference numeral 70 in FIG. 1 denotes an ECU (Electronic Control Unit) that comprehensively controls the engine. The ECU 70 includes a microprocessor including a CPU, a ROM, a RAM, and the like, and information from various sensors including the air flow sensor SN1 and the O ₂ sensor SN2 is sequentially input to the ECU 70.

The ECU 70 is connected with a warning device 71 such as a warning lamp provided on an instrument panel (not shown). The warning device 71 warns the driver when a specific abnormality occurs in the engine or a vehicle equipped with the engine. In this example, the ECU 70 determines the connection state of the blow-by gas piping 40 with respect to the compressor housing 23 (intake air inlet pipe portion 23b) based on each input information (intake air amount, oxygen amount) from the air flow sensor SN1 and the O ₂ sensor SN2. When it is determined that the blow-by gas pipe 40 is disconnected from the compressor housing 23, a control signal is output to activate the warning device 71. That is, in this embodiment, the ECU 70, the sensors SN1, SN2 and the warning device 71 are OBD (On Board Diagnostics System / self-fault diagnosis device) for minimizing the discharge of harmful substances (blow-by gas) from the engine. Function as.

(Detailed structure of blow-by gas recirculation device)
In this embodiment, the blow-by gas recirculation device of the present invention is mainly configured by the turbocharger 20 (compressor housing 23) and the blow-by gas pipe 40.

  2 and 3 show a part of the turbocharger 20, FIG. 2 is a perspective view, and FIG. 3 shows the turbocharger 20 in a sectional view.

  As shown in both drawings, the end of the blow-by gas pipe 40 is connected to the turbocharger 20. More specifically, the compressor housing 23 of the turbocharger 20 includes a housing main body 23a containing the compressor 24, and a cylindrical intake introduction pipe portion 23b connected to the housing main body 23a. The compressor housing 23 has a structure in which the housing main body 23a and the intake air introduction pipe portion 23b are integrally formed of the same metal material, for example, an aluminum alloy. A connection port 60 having a circular opening 61 is formed in the peripheral wall portion of the intake introduction pipe portion 23b, and the end of the blow-by gas pipe 40 is connected to the connection port 60.

  The blow-by gas pipe 40 includes a pipe body 41 made of a flexible resin hose and the like, and a connecting member 42 (corresponding to the connecting portion of the present invention) attached to the end thereof. The connecting member 42 is for detachably fixing the blow-by gas pipe 40 to the intake introduction pipe portion 23b.

  As shown in FIGS. 3 and 5 to 7, the connecting member 42 includes a cylindrical joint portion 43 that is inserted into the pipe body 41 and a fitting portion 45 that is fitted into the opening 61 of the connection port 60. And a flange portion 44 provided therebetween. The connecting member 42 has a structure in which the joint portion 43, the flange portion 44, and the fitting portion 45 are integrally molded from the same resin material.

  The connecting member 42 is formed by press-fitting the joint portion 43 into the pipe body 41 and then fastening the pipe body 41 and the joint portion 43 together by a caulking type hose fixing band or the like. 41 is fixed to the end. Then, as shown in FIGS. 2 and 3, the fitting portion 45 is inserted into the opening 61 of the connection port 60, and the flange portion 44 is fastened to the end surface of the connection port 60 by the bolt B1. The connecting member 42 is fixed to the housing body 23a. Specifically, the coupling member 42 is fastened to the connection port 60 by screwing and inserting the bolt B <b> 1 into the screw hole 62 on the end surface of the connection port 60 through the through hole 44 a of the flange portion 44. As a result, the end of the blow-by gas pipe 40 is detachably fixed to the intake air inlet pipe 23 b of the compressor housing 23.

  The connecting member 42 has a communication passage 46 that allows the pipe main body 41 and the intake air introduction pipe portion 23 b to communicate with each other through the joint portion 43 and the fitting portion 45. The communication passage 46 extends in the radial direction of the intake introduction pipe portion 23b (a direction orthogonal to the center line of the intake introduction pipe portion 23b). The fitting portion 45 has an outer diameter that can be fitted inside the opening 61 of the connection port 60, and the communication passage 46 has a center C2 fitted as shown in FIG. It is provided at a position eccentric from the center of the portion 45, that is, the center C1 of the opening 61 to the housing body 23a side (left side in FIG. 3). The diameter of the communication path 46 is set to be sufficiently smaller than the diameter of the opening 61.

  As shown in FIGS. 3, 4, 6, and 7, among the fitting portions 45 of the connecting member 42, the side surface on the housing body 23 a side is recessed toward the side opposite to the housing body 23 a and the opening 61. A groove 45a extending in a direction parallel to the center line is formed. Thus, a portion of the communication path 46 corresponding to the fitting portion 45 is formed by a space surrounded by the inner surface of the fitting portion 45 a and the inner peripheral surface of the opening 61.

  Note that the surface of the fitting portion 45 that faces the inside of the intake introduction pipe portion 23b is a curved surface along the inner peripheral surface of the intake introduction pipe portion 23b and is formed to be flush with the inner peripheral surface. Has been.

(Operational effect of the blow-by gas recirculation device)
According to the configuration of the above embodiment, the blow-by gas generated in the engine body 1 merges with the intake air of the turbocharger 20 through the blow-by gas pipe 40. Specifically, the air flows from the pipe main body 41 of the blow-by gas pipe 40 to the intake air in the intake air inlet pipe portion 23 b of the compressor housing 23 through the communication passage 46 of the connecting member 42 and the opening 61.

  According to this configuration, when the turbocharger 20 is actuated to raise the temperature of the housing body 23a of the compressor housing 23, the thermal energy is transmitted to the connecting member 42 via the intake air introduction pipe portion 23b, and the communication passage 46 Ambient temperature rises. Therefore, the dew condensation water generated in the blow-by gas pipe 40 is suppressed from icing to the inlet part of the blow-by gas to the intake inlet pipe part 23 b, that is, the outlet part of the communication path 46. In particular, a portion of the communication path 46 corresponding to the fitting portion 45 is surrounded by the inner surface of the groove 45a formed in the fitting portion 45 and the inner peripheral surface of the opening 61 of the intake air introduction pipe portion 23b. The blow-by gas flowing through the communication passage 46 is in direct contact with the intake air inlet pipe portion 23b. Therefore, heat input to the blow-by gas is promoted, and it is effectively suppressed that condensed water in the blow-by gas freezes on the outlet portion of the communication passage 46.

  Further, according to the configuration of the above-described embodiment, the blow-by gas is introduced into the intake introduction pipe portion 23b through the communication passage 46 formed in the connecting member 42, and thus the above-mentioned formed on the peripheral wall portion of the intake introduction pipe portion 23b. While the diameter of the opening 61 is set to be relatively large, the diameter of the communication path 46 can be kept small. That is, while the pipe body 41 having a small diameter is applied, the intake introduction pipe portion 23b can be largely opened through the opening 61 when the blow-by gas pipe 40 is not connected. Therefore, as described above, there is an advantage that the increase in the diameter of the blow-by gas pipe 40, particularly the increase in the diameter of the pipe body 41, can be suppressed while providing the OBD function related to the blow-by gas recirculation device.

Here, the advantages will be described in detail. In this embodiment, as described above, whether ECU70, each input information (amount of intake air, oxygen) from the air flow sensor SN1 and the O ₂ sensor SN2 or blow-by gas piping 40 based on is connected to the intake air introduction pipe portion 23b Is determined. For example, the ECU 70 periodically obtains the ratio of the oxygen amount to the intake air amount. If the value exceeds a predetermined value, the ECU 70 determines that the blow-by gas pipe 40 is disconnected from the intake air inlet pipe portion 23b, and the warning device 71. Is activated. This notifies the driver of an abnormality in the blowby gas piping 40. That is, when the blow-by gas pipe 40 is detached from the intake air inlet pipe portion 23b and the opening 61 is opened, most of the intake air is taken in through the opening 61 having a low resistance. Therefore, while the detection value (intake amount) of the air flow sensor SN1 greatly decreases, the phenomenon that the amount of oxygen in the exhaust gas (detection value of the air flow sensor SN1) hardly changes occurs, and the ratio of the oxygen amount to the intake amount is large. Exceeds the predetermined value. The ECU 70 detects this and activates the warning device 71. In this case, it is desirable that the opening 61 is large in order to perform the detection quickly and reliably. This is because the detected value of the air flow sensor SN1 is significantly reduced by increasing the amount of intake air taken in through the opening 61, and as a result, the abnormality detection of the blow-by gas pipe 40 can be performed more quickly and reliably. is there. However, when the opening 61 of the intake pipe 23b is made larger, the diameter of the blow-by gas pipe is also increased, and as a result, it becomes difficult to route the engine, so that the layout of the entire engine may be affected. However, according to the configuration of the above embodiment, the blow-by gas is introduced into the intake introduction pipe portion 23b through the communication passage 46 of the connecting member 42, so that the diameter of the opening 61 of the intake introduction pipe portion 23b is relatively small. The communication path 46 itself can be kept small in diameter while being set large. That is, it is possible to apply the pipe body 41 having a small diameter while opening the intake introduction pipe portion 23b through the opening 61.

  In addition, when the said opening part 61 becomes large, the area of the internal peripheral surface of the said opening part 61 will become large, and the dew condensation water in blowby gas will adhere easily to the said internal peripheral surface etc., and this may become an ice lump. Concerned. However, according to the configuration of the above embodiment, the space inside the opening 61 other than the communication passage 46 is filled with the fitting portion 45 of the connecting member 42. As described above, the communication passage 46 is An opening 61 is provided at a position eccentric from the center C1 of the opening 61 toward the housing body 23a so that the inner peripheral surface of the opening 61 and the blow-by gas are in contact with each other. Therefore, regardless of the size of the opening 61, it is possible to effectively prevent the condensed water in the blow-by gas from icing on the inner peripheral surface or the vicinity of the communication path 46. Therefore, according to the configuration of the above-described embodiment, it is possible to effectively prevent the communication passage 46 serving as the blow-by gas inlet port from icing while solving the problem at the time of mounting the OBD, that is, increasing the diameter of the blow-by gas pipe 40. Can be suppressed.

  Further, according to the configuration of the above-described embodiment, since the space inside the opening 61 is filled with the fitting portion 45, a recess is formed by the opening 61 on the inner peripheral surface of the intake air inlet pipe portion 23b. Is prevented. Therefore, there is an advantage that it is possible to prevent the intake air flow from being disturbed by the concave portion, thereby reducing the supercharging performance of the turbocharger 20 and generating abnormal noise. In particular, according to the configuration of the above embodiment, the surface of the fitting portion 45 that faces the inside of the intake introduction pipe portion 23b is a curved surface along the inner peripheral surface of the intake introduction pipe portion 23b. Since it is formed to be flush with the surface, it is possible to prevent the intake flow from being disturbed to a higher degree.

  Although not mentioned in the description of the above embodiment, the connecting member 42 of the blow-by gas pipe 40 is formed of a material having a lower thermal conductivity than the compressor housing 23 (intake air inlet pipe portion 23b). Is preferred. This is to suppress the temperature drop of the blow-by gas introduced into the intake introduction pipe portion 23b through the communication passage 46 to a higher degree, particularly in a cold district. That is, the temperature of the intake pipe portion 23b made of aluminum alloy having a relatively high thermal conductivity is kept relatively high by the heat conduction from the housing main body 23a on the downstream side, but the intake (outside air) on the upstream side. There is a tendency to be affected and lowered. Therefore, when the connecting member 42 is formed of a material having a thermal conductivity equal to or higher than that of the aluminum alloy, the amount of heat transferred from the connecting member 42 to the intake air (outside air) increases, and the temperature rise effect of the blow-by gas May impair the effectiveness of. On the other hand, when the connecting member 42 is formed of a material having a lower thermal conductivity than the compressor housing 23 (intake air inlet pipe portion 23b), the connecting member 42 to the intake air (outside air) as described above. Since heat transfer is suppressed, this makes it possible to more reliably enjoy the temperature rise effect of blow-by gas.

  The engine to which the present invention has been applied has been described above. However, the engine is a preferable example of an engine to which the blow-by gas recirculation device according to the present invention is applied, and the specific configuration of the engine and the blow-by gas recirculation device is as follows. Modifications can be made as appropriate without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Engine main body 10 Intake passage 20 Turbocharger 23 Compressor housing 23a Housing main body 23b Intake introduction pipe part 30 Exhaust passage 40 Blow-by gas piping 41 Pipe main body 42 Connecting member 43 Joint part 44 Flange part 45 Fitting part 46 Communication path

Claims (8)

A blow-by gas recirculation device for a turbocharged engine,
A turbocharger having a compressor housing including a housing body and an intake air inlet pipe portion provided integrally therewith;
A blow-by gas pipe connected to the intake air introduction pipe part and merging the blow-by gas discharged from the engine body with the intake air in the intake air introduction pipe part, and
The intake air introduction pipe portion has a peripheral wall having an opening formed for blow-by gas introduced into the peripheral surface,
The blow-by gas pipe includes a pipe main body, and a connecting portion that is provided at an end of the pipe main body and is detachably fixed to the intake air inlet pipe portion.
The connecting portion is fixed to the peripheral wall portion in a state where the opening portion is closed, and has a smaller inner diameter than the opening portion at a position eccentric from the center of the opening portion toward the housing body side, and a piping main body. A blow-by gas recirculation device comprising a communication passage that communicates with an intake pipe. The blow-by gas recirculation device according to claim 1,
The compressor housing is a blow-by gas recirculation device in which a housing main body and an intake introduction pipe portion are integrally formed of the same metal material. In the blowby gas recirculation device according to claim 1 or 2,
The connecting portion includes a fitting portion that is detachably fitted into the opening and fills a portion other than the communication path in a space inside the opening. Gas reflux device. The blow-by gas recirculation device according to claim 3,
The intake pipe portion has an inner peripheral surface with a circular cross section,
Of the fitting portion, a surface facing the inside of the intake introduction pipe portion is a curved surface along the inner peripheral surface of the intake introduction pipe portion and has a shape that is flush with the inner peripheral surface. The blow-by gas recirculation apparatus characterized by the above-mentioned. In the blowby gas recirculation device according to claim 3 or 4,
A groove portion that is recessed toward the side opposite to the housing main body and extends in a direction parallel to the center line of the opening is formed on a side surface of the fitting portion on the housing main body side,
At least a part of the communication passage is formed by a space surrounded by an inner surface of the groove and an inner peripheral surface of the opening. In the blowby gas recirculation device according to any one of claims 1 to 5,
The blow-by gas recirculation device, wherein the connecting portion is formed of a material having a lower thermal conductivity than the intake air introduction pipe portion. A blow-by gas recirculation device for a turbocharged engine,
A turbocharger having a compressor housing including a housing body and an intake air inlet pipe portion having an inner circumferential surface having a circular cross section, which is provided integrally therewith;
A blow-by gas pipe connected to the intake air introduction pipe part and merging the blow-by gas discharged from the engine body with the intake air in the intake air introduction pipe part, and
The intake pipe portion has a peripheral wall portion in which an opening for introducing a blow-by gas is formed,
The blow-by gas pipe includes a pipe main body, and a connecting portion that is provided at an end of the pipe main body and is detachably fixed to the intake air inlet pipe portion.
The connecting portion is fixed to the peripheral wall portion in a state where the opening portion is closed, and has a smaller inner diameter than the opening portion at a position eccentric from the center of the opening portion toward the housing body side, and a piping main body. A communication passage that communicates with the intake air inlet pipe portion, and a fitting portion that is detachably fitted to the opening and fills a portion of the space inside the opening other than the communication passage. And
Of the fitting portion, a surface facing the inside of the intake introduction pipe portion is a curved surface along the inner peripheral surface of the intake introduction pipe portion and has a shape that is flush with the inner peripheral surface. The blow-by gas recirculation apparatus characterized by the above-mentioned. A blow-by gas recirculation device for a turbocharged engine,
A turbocharger having a compressor housing including a housing body and an intake air inlet pipe portion provided integrally therewith;
A blow-by gas pipe connected to the intake air introduction pipe part and merging the blow-by gas discharged from the engine body with the intake air in the intake air introduction pipe part, and
The intake pipe portion has a peripheral wall portion in which an opening for introducing a blow-by gas is formed,
The blow-by gas pipe includes a pipe main body, and a connecting portion that is provided at an end of the pipe main body and is detachably fixed to the intake air inlet pipe portion.
The connecting portion is fixed to the peripheral wall portion in a state where the opening portion is closed, and has a smaller inner diameter than the opening portion at a position eccentric from the center of the opening portion toward the housing body side, and a piping main body. A communication passage that communicates with the intake air inlet pipe portion, and a fitting portion that is detachably fitted to the opening and fills a portion of the space inside the opening other than the communication passage. And
A groove portion that is recessed toward the side opposite to the housing main body and extends in a direction parallel to the center line of the opening is formed on a side surface of the fitting portion on the housing main body side,
At least a part of the communication passage is formed by a space surrounded by an inner surface of the groove and an inner peripheral surface of the opening.

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