JP2016044601A - EGR system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an EGR system capable of treating condensed water separated from exhaust gas while simplifying a device.SOLUTION: An EGR system 1 includes an EGR pipe 2 for recirculating part of exhaust gas exhausted from a combustion chamber of an engine 10 to the intake side of the engine 10, a discharge electrode 26 for causing electric discharge in the EGR pipe 2 to generate ions, a dust collection electrode 27 for trapping misty water component charged in the EGR pipe 2, a condensed water guide-out part 22 utilizing a capillary phenomenon for drawing the condensed water as the water component trapped by the dust collection electrode 27 to the outer surface side of the EGR pipe 2, and a vaporizing part 23 for vaporizing the condensed water drawn by the condensed water guide-out part 22.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an EGR system.

  Conventionally, an EGR [Exhaust Gas Recirculation] system that recirculates exhaust gas to the intake side is known as an effective means for reducing NOx of exhaust gas in an engine, for example (see, for example, Patent Document 1). In the EGR system of Patent Document 1, moisture (condensed water) contained in the EGR gas recirculated to the intake side is separated, and the separated moisture is stored in a water storage section.

JP 2013-147988 A

  In the technique described in Patent Document 1, a control valve is provided in a flow path for discharging condensed water from the water storage unit to control the flow of condensed water discharged from the water storage unit. Further, it is conceivable to provide a water level sensor for detecting the water level of the condensed water in the water storage unit and control the flow of the condensed water based on the water level of the condensed water. If the water level sensor, the control valve, and the like are provided, the manufacturing cost and the maintenance cost increase. In addition, if the water level sensor and the control valve are corroded by the condensed water, the maintenance cost is further increased.

    An object of the present invention is to provide an EGR system capable of treating the condensed water separated from the exhaust gas by simplifying the apparatus.

  The EGR system of the present invention includes an EGR pipe that recirculates a part of the exhaust gas exhausted from the combustion chamber of the engine to the intake side of the engine, a discharge electrode that discharges the EGR pipe to generate ions, and an EGR pipe. A dust collecting electrode that collects the mist-like water charged in the step, and a condensed water deriving unit that draws condensed water, which is water collected by the dust collecting electrode, to the outer surface side of the EGR pipe by using a capillary phenomenon; And a vaporization unit that vaporizes the condensed water drawn by the condensed water deriving unit.

  In this EGR system, a positive ion and a negative ion can be generated in the EGR pipe by generating a discharge between the discharge electrode and the dust collecting electrode. Thereby, the mist-like condensed water charged in the EGR pipe is attracted to the dust collecting electrode and collected. The condensed water collected by the dust collecting electrode is attracted to the outer surface side of the EGR pipe using the capillary phenomenon and vaporized. Therefore, it is not necessary to provide a control valve or a water level sensor for controlling the flow of the condensed water, the apparatus can be simplified, and the condensed water separated from the exhaust gas can be processed.

  The EGR system includes an EGR cooler that is provided in the EGR pipe and cools the exhaust gas. The discharge electrode is disposed in the EGR pipe downstream of the EGR cooler. The dust collecting electrode is disposed in the EGR pipe downstream of the discharge electrode. The EGR pipe is provided with a through hole through which the condensed water collected by the dust collecting electrode is passed to the outer surface side of the EGR pipe, and the condensed water outlet part is a member for utilizing capillary action It is also possible to have a structure in which a fiber member for derivation is included and the fiber member for derivation is disposed in the through hole. In the EGR system having such a configuration, positive ions and negative ions are generated by the discharge electrode arranged downstream of the EGR cooler, and the mist-like condensed water is positively charged. The positively charged condensed water is discharged to the discharge electrode. It is attracted to and collected by a dust collecting electrode arranged downstream of the slab. Since the EGR pipe is provided with a through-hole, and the lead-out fiber member is arranged in the through-hole, the condensed water attracted to the dust collecting electrode is capillarity due to the lead-out fiber member arranged in the through hole. Using this, it is led out to the outer surface side of the EGR pipe and vaporized.

  The vaporization section is provided on the outer surface side of the EGR pipe, and is provided with an air flow path through which compressed air is supplied and the compressed air flows, and condensed water that is disposed in the air flow path and is led out by the fiber member for lead-out. And a vaporizing fiber member that draws and vaporizes using a capillary phenomenon. According to the EGR system having this configuration, the condensed water led out by the lead-out fiber member is drawn into the air flow path by the vaporizing fiber member. Since compressed air is supplied to the air flow path, the condensed water drawn into the air flow path by the vaporizing fiber member is exposed to the flow of the compressed air and vaporized. Note that “arranged in the air flow path” includes, for example, a state where the air flow path is disposed adjacent to the air flow path so as to be in contact with the compressed air flowing in the air flow path.

  In addition, the EGR system draws condensed water that is arranged in the connecting pipe that connects the outer surface side of the EGR pipe and the vaporizing section, and that is arranged in the connecting pipe, and that is led out by the fiber member for derivation, using capillary action. The structure provided with the fiber member for transfer to transfer may be sufficient. In the EGR system having this configuration, since the transfer fiber member is accommodated in the connection pipe, the transfer fiber member can be suitably held and guided. Further, since the transfer fiber member soaked with the condensed water is prevented from coming into contact with other parts, the other parts are prevented from getting wet or corroded.

  According to the present invention, since condensed water can be sucked using the capillary phenomenon, the apparatus can be simplified and the condensed water separated from the exhaust gas can be treated.

It is the schematic which shows the engine provided with the EGR system of 1st Embodiment of this invention. It is a schematic sectional drawing which shows the collection part of the EGR system of 1st Embodiment of this invention. It is a schematic sectional drawing which shows the collection part and vaporization part of the EGR system of 1st Embodiment of this invention. It is the schematic which shows the EGR system of 2nd Embodiment of this invention. It is a schematic sectional drawing which shows the collection part of the EGR system of 2nd Embodiment of this invention. 6A is a view showing the vaporization portion from the front, FIG. 6B is a cross-sectional view of the vaporization portion taken along the direction in which the tail pipe extends, and FIG. 6C is a view showing the vaporization portion. FIG. 6 (d) is a view from the rear, and is a view taken along line AA in FIG. 6 (b).

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the same part or an equivalent part, and the overlapping description is abbreviate | omitted.

  As shown in FIG. 1, the EGR system 1 is mounted on an engine 10 such as a diesel engine, for example, and at least a part of exhaust gas discharged from a combustion chamber of an engine body 10 a of the engine 10 is sent to the intake side of the engine 10. Reflux.

  The engine 10 is a turbocharged engine including a turbocharger 11, and an engine body 10a of the engine 10 has one or a plurality of cylinders (6 cylinders in the illustrated example). The engine 10 is not limited to a diesel engine, and may be a gasoline engine. The applied vehicle is not limited, and may be, for example, a large vehicle such as a truck, a bus, or a heavy machine, a medium-sized vehicle, a normal passenger car, a small vehicle, or a light vehicle. The engine 10 may be applied to, for example, a ship.

  The turbocharger 11 is provided with an exhaust turbine 11a that is supplied with exhaust gas from the engine 10 and is driven to rotate. The inlet side of the exhaust turbine 11 a is connected to the exhaust manifold 12 of the engine 10, and the outlet side of the exhaust turbine 11 a is connected to the exhaust pipe 14.

  The turbocharger 11 has a compressor 11b that is coaxially connected to the exhaust turbine 11a and transmits rotational energy. The inlet side of the compressor 11 b is connected to a suction duct 16 that sucks outside air, and the outlet side of the compressor 11 b is connected to an intake pipe 13 of the engine 10. The outside air sucked through the suction duct 16 is compressed by the compressor 11 b after being removed by impurities such as dust by an air cleaner (not shown) and supplied to the intake pipe 13. The intake pipe 13 connects the outlet of the compressor 11 b and the intake manifold 17 of the engine 10.

  The intake pipe 13 is provided with an intercooler 15 that cools the compressed air that has been pressurized by the compressor 11b. The air (fresh air) discharged from the intercooler 15 is merged with the exhaust gas (EGR gas) recirculated by the EGR system 1 and is sucked into the engine body 10 a via the intake manifold 17.

  The EGR system 1 is an HPL (High Pressure Loop) system that recirculates high-pressure exhaust gas before passing through the exhaust turbine 11a of the turbocharger 11 to the intake side, and includes an EGR pipe 2, an EGR cooler 3, and an EGR valve 4. It has. The EGR system may be an LPL (Low Pressure Loop) system that recirculates low-pressure exhaust gas that has passed through the exhaust turbine 11a to the intake side (from the exhaust pipe 14 to the intake duct 16).

  One end side of the EGR pipe 2 is connected to the exhaust manifold 12, and the other end side is connected to the EGR junction 13 a downstream of the intercooler 15 in the intake pipe 13. The EGR pipe 2 recirculates at least a part of the exhaust gas to the EGR merging portion 13a.

  The EGR cooler 3 cools the exhaust gas and is provided in the EGR pipe 2. The EGR cooler 3 is not particularly limited, and various EGR coolers can be used. The EGR cooler 3 may be, for example, an air-cooled type or a water-cooled type. The EGR valve 4 is disposed between the EGR cooler 3 and the EGR merging portion 13a in the EGR pipe 2. As this EGR valve 4, for example, an electromagnetic valve is employed, and the recirculation of exhaust gas to the intake side is permitted or stopped by opening and closing the valve.

  Here, the EGR system 1 collects condensed water, which is moisture separated from the exhaust gas flowing through the EGR pipe 2, and a condensed water discharge device 20 that discharges the collected condensed water to the outside of the EGR pipe 2. I have. As shown in FIG. 2, the condensed water discharge device 20 includes a collection unit 21, a condensed water derivation unit 22, a vaporization unit 23, a blower unit 24, and a discharge unit 25. The condensed water discharger 20 includes a fiber member 30 as a member for attracting condensed water using a capillary phenomenon, and the fiber member 30 includes a fiber member 30a for derivation and a fiber member 30b for vaporization.

  The collection unit 21 is provided downstream of the EGR cooler 3 and upstream of the EGR valve 4 in the EGR pipe 2. The collection unit 21 includes a discharge electrode 26, a dust collection electrode 27, and a power supply unit 28. The discharge electrode 26 and the dust collecting electrode 27 are supplied with electric power from the electric power supply unit 28 and generate corona discharge in the EGR pipe 2. By generating corona discharge in the EGR pipe 2, positive ions and negative ions are generated.

  The discharge electrode 26 is disposed downstream of the EGR cooler 3, and the dust collection electrode 27 is disposed downstream of the discharge electrode 26. The discharge electrode 26 is a rod-shaped electrode, for example, and extends in the radial direction of the EGR pipe 2. Both ends of the discharge electrode 26 are fixed to the tube wall of the EGR pipe 2 and arranged so as to be in contact with the exhaust gas flowing in the EGR pipe 2. A plurality of discharge electrodes 26 may be provided in a cross section orthogonal to the extending direction of the EGR pipe 2. The plurality of discharge electrodes 26 may be arranged in a lattice shape or may be arranged in parallel.

  As shown in FIGS. 2 and 3, the dust collection electrode 27 is, for example, a cylindrical electrode, and is disposed along the inner peripheral surface (inner wall surface) of the EGR pipe 2. The center line direction of the dust collection electrode 27 is arranged along the extending direction of the EGR pipe 2, and the exhaust gas flows on the inner surface side of the cylindrical dust collection electrode 27. The dust collecting electrode 27 attracts and collects condensed water, which is mist-like moisture charged positively.

  A through hole 29 is formed in the EGR pipe 2 and the dust collecting electrode 27 so as to penetrate from the inner surface side of the dust collecting electrode 27 to the outer surface side of the EGR pipe 2. The through hole 29 is formed as a passage through which condensed water drawn to the dust collection electrode 27 passes to the outer surface side of the EGR pipe 2. The condensed water deriving unit 22 draws condensed water collected by the dust collecting electrode 27 to the outer surface side of the EGR pipe 2 using a capillary phenomenon. The condensed water deriving unit 22 includes a fiber member 30a for deriving as a member for utilizing the capillary phenomenon. The leading fiber member 30 a is accommodated in the through hole 29. The leading fiber member 30a may be a woven fabric or a knitted fabric, for example. The fiber member 30 may be in the form of a band, or may be in the form of a thread or string.

  The lead-out fiber member 30 a is held by a cylindrical through-hole portion 33 arranged in the through-hole 29. The through-hole portion 33 is inserted into the through-hole 29 and holds the lead-out fiber member 30 a continuous from the inner surface side of the dust collecting electrode 27 to the outer surface side of the EGR pipe 2. The through-hole portion 33 is provided at a plurality of locations (four locations in the present embodiment) in a cross section orthogonal to the extending direction of the EGR pipe 2. The through hole portion 33 communicates the inside of the EGR pipe 2 and the vaporizing portion 23.

  The vaporizing unit 23 includes a cylindrical outer tube 23a disposed outside the EGR pipe 2, and the vaporizing fiber member 30b and the fiber member holding unit 31 are disposed in the outer tube 23a as shown in FIG. The air flow path 32 is provided.

  The vaporizing fiber member 30b is connected to the lead-out fiber member 30a and draws the condensed water led out by the lead-out fiber member 30a by using a capillary phenomenon to vaporize. The fiber member 30b for vaporization may be a woven fabric or a knitted fabric, for example. The fiber member 30 may be in the form of a band, or may be in the form of a thread or string. The vaporizing fiber member 30 b is disposed on the outer surface side of the EGR pipe 2. The vaporizing fiber member 30 b is arranged so as to cover the EGR pipe 2 in the entire circumference of the EGR pipe 2.

  In addition, the vaporizing fiber member 30 b is arranged in two layers in the radial direction of the EGR pipe 2. The fiber member 30b for vaporization has the 1st layer 30c arrange | positioned at the EGR piping 2 side, and the 2nd layer 30d arrange | positioned outside the 1st layer 30c. The first layer 30c and the second layer 30d are spaced apart in the radial direction of the EGR pipe 2. In addition, the first layer 30 c and the second layer 30 d are partially connected in the circumferential direction of the EGR pipe 2. In the vaporizing fiber member 30b, for example, the first layer 30c and the second layer 30d are connected at four locations. The vaporizing fiber member 30b has a predetermined length in the direction in which the EGR pipe 2 extends.

  The fiber member holding unit 31 holds the fiber member 30b for vaporization and forms a passage through which condensed water passes. The fiber member holding part 31 has a first layer part 34, a connecting part 35, and a second layer part 36. The first layer portion 34 is disposed along the circumferential direction of the EGR pipe 2 in the cross section of the EGR pipe 2. A plurality (four in this embodiment) of first layer portions 34 are provided corresponding to the through-hole portions 33. The first layer portion 34 is a portion that holds the first layer 30 c of the fiber member 30 b for vaporization, and holds the first layer 30 c from both radial sides of the EGR pipe 2. In the circumferential direction of the EGR pipe 2, one end side of the first layer portion 34 is connected to the through-hole portion 33, and the other end side is communicated with the second layer portion 36 via the connecting portion 35. The other end side of the first layer portion 34 is disposed so as to approach the through hole portion 33 adjacent in the circumferential direction.

  The connecting portion 35 extends in the radial direction in the cross section orthogonal to the extending direction of the EGR pipe 2 and holds the portion of the fiber member 30b for vaporization that connects the first layer 30c and the second layer 30d. The connecting part 35 holds the fiber member 30b for vaporization from both sides of the EGR pipe 2 in the circumferential direction.

  The second layer portion 36 holds the second layer 30d of the fiber member 30b for vaporization. The second layer portion 36 is provided on the entire circumference in the circumferential direction of the EGR pipe 2, and holds the second layer 30d of the fiber member 30b for vaporization from both sides in the radial direction.

  The air flow path 32 is a flow path through which air flows, and is provided adjacent to the fiber member 30b for vaporization. The air flow path 32 includes a first flow path 37 and a second flow path 38. The first flow path 37 is formed between the first layer 30 c and the second layer 30 d in the radial direction of the EGR pipe 2. The second flow path 38 is formed outside the second layer 30 d in the radial direction of the EGR pipe 2. The first flow path 37 and the second flow path 38 have a predetermined length in the extending direction of the EGR pipe 2, and are formed longer than the dust collection electrode 27, for example. The first flow path 37 and the second flow path 38 are communicated with each other at both ends in the extending direction of the EGR pipe 2. Further, the fiber member holding portion 31 is provided with a plurality of vent holes (not shown), a space inside the fiber member holding portion 31, a first flow path 37 that is a space outside the fiber member holding portion 31, and The second flow path 38 is in communication. As a result, the air flowing through the first flow path 37 and the second flow path 38 can be brought into contact with the vaporizing fiber member 30 b held by the fiber member holding portion 31. The condensed water sucked by the vaporizing fiber member 30 b comes into contact with the compressed air flowing through the first flow path 37 and the second flow path 38 and vaporizes. The vaporizing fiber member 30 b may be disposed so as to protrude into the air flow path 32 through the ventilation hole of the fiber member holding portion 31.

  The blower unit 24 includes a compressed air supply unit 40 and an air supply pipe 41. The compressed air supply unit 40 is, for example, an air compressor, and pressurizes air. The compressed air supply unit 40 is provided in a vehicle on which the engine 10 is mounted. For example, the compressed air supply unit 40 supplies compressed air for driving a brake and compressed air used for an air suspension. For example, the air compressor is driven by the power of the engine 10 to compress air. As the compressed air supply unit 40, a pressure accumulator that stores compressed air can be used.

  The air supply pipe 41 is a pipe that connects the compressed air supply unit 40 and the air flow path 32 of the vaporization unit 23. The compressed air discharged from the compressed air supply unit 40 flows through the air supply pipe 41 and is supplied into the air flow path 32.

  The discharge part 25 has a discharge pipe 42 that connects the air flow path 32 of the vaporization part 23 and the exhaust pipe 14. The air that has passed through the air flow path 32 flows through the discharge pipe 42 and is introduced into the exhaust pipe 14.

  Next, the operation of the EGR system 1 will be described.

  In the EGR system 1, a part of the exhaust gas discharged from the engine body 10 a is supplied to the EGR pipe 2. After the exhaust gas supplied to the EGR pipe 2 is cooled by the EGR cooler 3, the flow rate is adjusted by the EGR valve 4, introduced into the intake pipe 13 by the EGR junction 13a, and mixed with fresh air. Then, the air is sucked into the engine body 10a. Thereby, a part of the exhaust gas is recirculated and supplied to the engine body 10a, so that the exhaust gas in the engine 10 can be reduced in NOx.

  Further, the exhaust gas flowing through the EGR pipe 2 is cooled by the EGR cooler 3, and the moisture in the gas is condensed. Downstream of the EGR cooler 3, the discharge electrode 26 and the dust collecting electrode 27 are energized, and corona discharge is generated in the EGR pipe 2. When corona discharge occurs, electrons are radiated into the EGR pipe 2, and exhaust gas collides with the discharge electrode 26, thereby generating positive ions and negative ions. When the polarity of the discharge electrode 26 is positive, the negative ions are neutralized, and the positive ions are attracted to the dust collection electrode 27 having a negative polarity by an electric attractive force. At this time, the mist-like water floating in the EGR pipe 2 is positively charged by adhering positive ions, and this positively-charged mist-like water is attracted to the dust collecting electrode 27 and collected. .

  Condensed water, which is water collected by the dust collecting electrode 27, soaks into the lead-out fiber member 30a in the through-hole 29 and is sucked by the capillary phenomenon of the lead-out fiber member 30a. Derived from inside to outside. The condensed water that has soaked into the leading fiber member 30a is sucked into the vaporizing fiber member 30b by capillary action and soaks into the first layer 30c and the second layer 30d.

  Further, the compressed air supplied from the compressed air supply unit 40 is introduced into the air flow path 32 of the vaporization unit 23. The compressed air supplied to the air flow path 32 flows through the first flow path 37 and the second flow path 38, and the fiber member 30 comes into contact with the compressed air flowing through the first flow path 37 and the second flow path 38. Therefore, the condensed water infiltrated into the fiber member 30b for vaporization is vaporized and flows along with the compressed air.

  The compressed air containing the vaporized condensed water is discharged from the vaporizing section 23, introduced into the exhaust pipe 14 through the discharge pipe 42, and discharged together with the exhaust gas.

  As described above, according to the EGR system 1 of the present embodiment, the condensed water W collected by the dust collection electrode 27 is drawn to the outside of the EGR pipe 2 using the capillary phenomenon and is vaporized by the vaporization unit 23. . Thereby, since it is not necessary to provide a control valve or a water level sensor for controlling the flow of the condensed water, the apparatus can be simplified and the condensed water separated from the exhaust gas can be processed.

  Further, in the EGR system 1, the condensed water can be collected from the exhaust gas in the EGR pipe 2, and the condensed water can be discharged to the outside of the EGR pipe 2 to be vaporized. Therefore, the condensed water in a liquefied state is It is prevented from being introduced into the engine body 10a. Thereby, generation | occurrence | production of the water hammer by condensed water can be prevented, and generation | occurrence | production of the combustion defect in the engine main body 10a can be suppressed. Moreover, since the entrance of liquefied condensed water into the engine body 10a is prevented, corrosion of the engine body 10a can be prevented.

  In the EGR system 1, the condensed water drawn to the dust collection electrode 27 is drawn by the fiber member 30 from the inside of the dust collection electrode 27 through the through hole 29 to the outside of the EGR pipe 2 using a capillary phenomenon. Since the air flow path 32 is formed outside the EGR pipe 2 and the compressed air flows, the condensed water sucked by the fiber member 30 is efficiently vaporized by the compressed air. Thereby, the efficiency of vaporization can be raised and the discharge amount of condensed water can be increased. Therefore, even if the cooling in the EGR cooler 3 is enhanced to increase the amount of condensed water generated, the condensed water can be efficiently vaporized. Therefore, the exhaust gas temperature can be lowered to further reduce NOx. Can do.

  Next, the EGR system 50 according to the second embodiment will be described. A description similar to that of the EGR system 1 of the first embodiment is omitted. As shown in FIGS. 4 and 5, the EGR system 50 collects condensed water, which is water separated from the exhaust gas flowing through the EGR pipe 2, and discharges the collected condensed water to the outside of the EGR pipe 2. The condensed water discharge device 51 is provided. As shown in FIG. 5, the condensed water discharge device 51 includes a collection unit 21, a condensed water deriving unit 52, a discharge unit 53, and a vaporization unit 54 (see FIG. 6). The condensed water discharge device 51 includes a fiber member 55 as a member for attracting condensed water using a capillary phenomenon, and the fiber member 55 includes a water absorbing portion 55a that is a fiber member for collection, and a fiber for discharge. It has the string-like part 55b which is a member, the string-like part 55c which is a fiber member for transfer, and the terminal part 55d which is a fiber member for vaporization.

  The collection part 21 has a water absorption part 55 a arranged so as to cover the inner surface of the dust collection electrode 27. The inner surface of the dust collection electrode 27 is a surface of the surface of the dust collection electrode 27 that faces the center of the EGR pipe 2. The water absorption part 55a is a fiber member formed in a cloth shape, for example.

  The condensed water deriving section 52 draws the condensed water collected by the dust collecting electrode 27 and soaked in the water absorbing section 55a to the outer surface side of the EGR pipe 2 using a capillary phenomenon. The condensed water lead-out part 52 has a string-like part 55 b that is a fiber member for lead-out as a member for utilizing the capillary phenomenon, and the string-like part 55 b passes through the through hole 29 from the inner surface of the dust collection electrode 27. The EGR pipe 2 is disposed up to the outer surface side. The string-like portion 55 b is connected to the water absorbing portion 55 a and is disposed so as to pass through the through hole 29. The string-like portions 55b and 55c and the end portion 55d are formed by twisting a plurality of thread-like fibers.

  The discharge part 53 has a string-like part 55 c that is a fiber member for transfer and a discharge pipe (connection pipe) 56. The discharge pipe 56 is a pipe that connects the through hole 29 (the outer surface side of the EGR pipe) and the vaporizing section 54. The string-like part 55 c is formed continuously with the string-like part 55 b that is a fiber member for derivation, and is arranged inside the discharge pipe 56. The string-like portion 55 c extends over the entire length of the discharge pipe 56. The discharge pipe 56 is disposed along a vehicle body frame 57 that extends in the front-rear direction of the vehicle, and extends to the rear portion of the vehicle. Specifically, the discharge pipe 56 is connected to the outer surface side of the tail pipe 14a which is the rear end portion of the exhaust pipe 14. The tail pipe 14 a is a downstream portion of the muffler 18 provided in the exhaust pipe 14.

  The vaporization unit 54 is provided outside the tail pipe 14a. The vaporization part 54 has the cylindrical outer cylinder part 54a arrange | positioned so that the outer surface of the tail pipe 14a may be covered, as FIG. 6 shows. The tail pipe 14a is disposed at the center of the outer cylinder portion 54a, and a gap is formed between the tail pipe 14a and the outer cylinder portion 54a in the radial direction of the tail pipe 14a.

  One end side of the outer cylinder part 54a is directed to the front of the vehicle, and the other end side of the outer cylinder part 54a is directed to the rear of the vehicle. As shown in FIGS. 6A and 6B, a cover plate 54b is provided on one end side of the outer tube portion 54a to prevent the outside air from entering from the front. The lid plate 54b is a circular plate having an opening at the center, and the tail pipe 14a is inserted through the opening at the center. Moreover, the outer peripheral part of the cover board 54b is joined to the outer cylinder part 54a. As shown in FIG. 6C, a support portion 54c having a plurality of openings is provided on the other end side of the outer cylinder portion 54a. A ring portion 54d is provided at the center of the support portion 54c, and a plurality of support rods 54e extending radially are provided on the outer periphery of the ring portion 54d. The tail pipe 14a is inserted through the opening of the ring portion 54d, and the ring portion 54d is fixed to the tail pipe 14a. One end side of the support rod 54e is connected to the ring portion 54d, and the other end side of the support rod 54e is connected to the outer cylinder portion 54a.

  An opening penetrating in the thickness direction is provided on a side portion of the outer cylinder portion 54a. The end portion 56a of the discharge pipe 56 passes through the opening on the side of the outer tube portion 54a and is inserted into the outer tube portion 54a. As shown in FIGS. 6A to 6D, the discharge pipe 56 is arranged in the vertical direction in the vicinity of the outer cylinder portion 54a, and is inserted downward into the outer cylinder portion 54a. The opening of the end portion 56a of the discharge pipe 56 is directed downward and is disposed so as to face a portion of the outer peripheral surface facing the upper side of the tail pipe 14a.

  The end portion 55d, which is a vaporizing fiber member, is formed continuously with the string-like portion 55c, which is a transfer fiber member, and is led downward from the end portion 56a of the discharge pipe 56. The end portion 55e is wound around the outer peripheral surface of the tail pipe 14a inside the outer cylinder portion 54a. The end portion 55e is arranged so as to be in contact with the tail pipe 14a and to transmit the heat of the exhaust gas flowing through the tail pipe 14a.

  Next, the operation of the EGR system 50 will be described.

  In the EGR system 50, as in the EGR system 1 of the first embodiment, the mist-like water floating in the EGR pipe 2 is positively charged with positive ions attached thereto, and this positively charged mist-like water Is attracted to the dust collecting electrode 27.

  Condensed water, which is water drawn to the dust collection electrode 27, is collected by a water absorption part 55 a provided on the inner surface of the dust collection electrode 27. The condensed water that has soaked into the water absorption part 55a is drawn using the capillary phenomenon, and is transferred to the string-like part 55c in the discharge pipe 56 through the string-like part 55b.

  The condensed water transmitted to the string-like part 55c in the discharge pipe 56 is attracted and transferred to the rear end side (vaporization part 54 side) of the string-like part 55c using the capillary phenomenon. Condensed water drawn to the rear end side through the string-like portion 55 c is transferred to the terminal end portion 55 d discharged from the end portion 56 a of the discharge pipe 56. The condensed water transmitted to the end portion 55d is heated by the exhaust gas flowing through the tail pipe 14a. The heat of the exhaust gas is transferred via the tail pipe 14a to the condensed water soaked in the end portion 55d. The condensed water is heated and vaporized, and is discharged from the opening on the rear end side of the outer cylinder portion 54a.

  As described above, according to the EGR system 50 of the present embodiment, the condensed water collected and attracted by the dust collecting electrode 27 is attracted to the outside of the EGR pipe 2 by using the capillary phenomenon, and is passed through the fiber member 55. It is transferred to the rear part and vaporized by the vaporizing part 54. Thereby, since it is not necessary to provide a control valve or a water level sensor for controlling the flow of the condensed water, the apparatus can be simplified and the condensed water separated from the exhaust gas can be processed.

  Moreover, in the EGR system 50, since the string-like part 55c of the fiber member 55 is accommodated in the discharge pipe 56, the string-like part 55c can be suitably held and guided. Further, since the string-like portion 55c soaked with condensed water is prevented from coming into contact with other members (for example, a vehicle body frame), other components are prevented from getting wet or corroded. .

  Further, in the EGR system 50, there is no need to blow compressed air by a compressor, for example, and vaporize condensed water, so that it is not necessary to install a special drive source.

  Further, in the EGR system 50, the front end of the outer cylinder part 54a of the vaporization part 54 is closed, so that the entry of outside air into the outer cylinder part 54a is prevented. This prevents rainwater from entering the outer cylinder portion 54a, thereby preventing a reduction in the evaporation efficiency of the condensed water in the vaporization portion 54.

  The present invention is not limited to the above-described embodiments, and various modifications as described below are possible without departing from the gist of the present invention.

  In the said embodiment, although illustrated about the vaporization part which vaporizes condensed water with the compressed air pressurized by the compressor, for example, by blowing exhaust gas and fresh air (air discharged from the intercooler), The structure which vaporizes condensed water may be sufficient. Moreover, the structure which vaporizes condensed water using the wind at the time of vehicle travel may be sufficient by arrange | positioning the edge part of a fiber member exposed to air | atmosphere.

  In the above embodiment, the end portion 55d of the fiber member 55 is wound around the tail pipe 14a, and the condensed water is heated and vaporized by the heat of the exhaust gas. However, the end portion 55d is brought into contact with other heat generating portions. Thus, the condensed water may be vaporized.

  Moreover, in the said embodiment, although disclosed about the structure by which the string-like part 55b of the fiber member 55 is accommodated in the inside of the discharge pipe 56, the string-like part 55b is a groove-shaped member by which the upper part was open | released, for example. It may be arranged on the other side, or it may be wound around other rod-like members and arranged up to the rear part of the vehicle. The discharge pipe may be arranged up to the front of the vehicle, or may be arranged in other directions.

  Moreover, in the said embodiment, although the dust collection electrode 27 is provided in the downstream of the discharge electrode 26, you may provide the dust collection electrode 27 in the upstream of the discharge electrode 26, and the dust collection electrode in both upstream and downstream. 27 may be provided.

  Moreover, although the cylindrical dust collection electrode 27 is disclosed in the above embodiment, the dust collection electrode 27 may be formed in a cylindrical shape by combining a plurality of arc-shaped members. The dust collecting electrode 27 may be a plate-like electrode, a rod-like electrode, or other shapes. The dust collecting electrode 27 is not limited to the one disposed on the inner wall surface of the EGR pipe 2, and may be disposed away from the inner wall surface of the EGR pipe 2.

  DESCRIPTION OF SYMBOLS 1,50 ... EGR system, 2 ... EGR piping, 3 ... EGR cooler, 4 ... EGR valve, 10 ... Engine, 10a ... Engine main body, 14 ... Exhaust pipe, 14a ... Tail pipe, 20, 51 ... Condensate drainage device, 26 ... discharge electrode, 27 ... dust collecting electrode, 29 ... through hole, 30, 55 ... fiber member, 30a ... fiber member for derivation, 30b ... fiber member for vaporization, 32 ... air flow path, 40 ... supply of compressed air 55b ... string-like part (fiber member for transfer), 55d ... terminal part (fiber member for vaporization), 56 ... discharge pipe.

Claims (4)

EGR piping that recirculates a part of the exhaust gas exhausted from the combustion chamber of the engine to the intake side of the engine;
A discharge electrode for generating ions by discharging into the EGR pipe;
A dust collecting electrode for collecting mist-like water charged in the EGR pipe;
A condensed water deriving unit that draws condensed water, which is the moisture collected by the dust collecting electrode, to the outer surface side of the EGR pipe using a capillary phenomenon;
An EGR system comprising: a vaporization unit that vaporizes the condensed water drawn by the condensed water deriving unit. An EGR cooler provided in the EGR pipe for cooling the exhaust gas;
The discharge electrode is disposed downstream of the EGR cooler in the EGR pipe,
The dust collecting electrode is disposed on the inner wall surface of the EGR pipe downstream of the discharge electrode,
The EGR pipe is provided with a through hole through which the condensed water collected by the dust collecting electrode passes to the outer surface side of the EGR pipe,
The condensed water lead-out part has a lead-out fiber member as a member for utilizing the capillary phenomenon,
The EGR system according to claim 1, wherein the leading fiber member is disposed in the through hole. The vaporization unit is provided on the outer surface side of the EGR pipe, and an air flow path through which the compressed air flows when compressed air is supplied;
The EGR system according to claim 2, further comprising: a vaporizing fiber member that is disposed in the air flow channel and draws and condenses the condensed water derived by the deriving fiber member using a capillary phenomenon. A connection pipe connecting the outer surface side of the EGR pipe and the vaporization section;
The EGR system according to claim 2, further comprising: a transfer fiber member that is disposed in the connection pipe and that draws and transfers the condensed water led out by the lead-out fiber member using a capillary phenomenon. .

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