JP6382636B2 - EGR system - Google Patents

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.

  An EGR system of the present invention includes an EGR pipe that recirculates a part of exhaust gas exhausted from an engine combustion chamber to the intake side of the engine, and a storage part that stores condensed water separated from the exhaust gas flowing through the EGR pipe. And a vaporization unit that sucks and vaporizes the condensed water stored in the storage unit using a capillary phenomenon.

  In this EGR system, the condensed water separated from the exhaust gas flowing through the EGR pipe is stored in the storage unit, and the stored condensed water is sucked and vaporized using a capillary phenomenon. Thereby, it is possible to eliminate the need to provide a control valve or a water level sensor for controlling the flow of the condensed water, and to simplify the apparatus.

In addition, the EGR system includes an outer tube through which gas flows and an inner tube that is a tubular storage portion disposed along the direction in which the outer tube extends inside the outer tube . In the EGR system having this configuration, by adopting a double tube structure, a gas can be flowed in the outer tube to be rectified, and a tubular reservoir as the inner tube can be arranged in the gas flow. Thereby, the condensed water stored in the tubular storage part can be sucked using the capillary phenomenon and exposed to the gas flowing in the outer tube, and the condensed water is easily vaporized.

In addition, the EGR system is provided in the EGR pipe and cools the exhaust gas, the EGR cooler is provided downstream of the EGR cooler, and collects the condensed water, and the condensed water collected in the collecting unit. And a drainage pipe connected to the storage part, and the storage part is provided with a through hole for deriving condensed water to the outer surface side of the storage part. has a thread-like member as a member for utilizing capillary phenomenon, threadlike members may be a configuration that is disposed over the outer surface side of the storage portion from the through hole. According to the EGR system having this configuration, the condensed water is collected by the collection unit provided downstream of the EGR cooler, and the collected condensed water is discharged and stored outside the EGR pipe through the drain pipe. Can do. Further, the condensed water provided in the storage part is led out to the outer surface side of the storage part through the through hole , and the condensed water is attracted and vaporized by utilizing a capillary phenomenon in the filamentous member provided on the outer surface side. Can do.

The EGR system of the present invention also stores 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, and condensate water separated from the exhaust gas flowing through the EGR pipe. The EGR cooler that cools the exhaust gas, and the EGR cooler that is provided in the EGR pipe, the vaporizer that sucks and condenses the condensed water stored in the reservoir using the capillary phenomenon, A collecting section for collecting condensed water; and a drain pipe for discharging condensed water collected by the collecting section to the outside of the EGR pipe and connected to the storing section. Is provided on the outer surface side of the storage portion, the vaporization portion has a thread-like member as a member for utilizing the capillary phenomenon, and the thread-like member extends from the through hole to the outer surface side of the storage portion. It is arranged over.

  Further, the EGR pipe is provided with an EGR valve upstream of the EGR merging portion, which is a merging portion with the intake pipe on the intake side, and the collecting portion has a slope between the EGR cooler and the EGR valve, and is vaporized. The portion is disposed upstream of the EGR merging portion of the intake pipe. According to the EGR system having this configuration, condensed water can be collected between the EGR cooler and the EGR valve, and the collected condensed water is disposed upstream of the EGR merging portion of the intake pipe. Can be vaporized. Since the intake gas flowing upstream from the EGR confluence portion of the intake pipe is dry compared with the exhaust gas flowing through the EGR pipe, the condensed water is vaporized by exposing the filamentary member to the dry intake gas. Can be performed efficiently.

  According to the present invention, the apparatus can be simplified, the condensed water separated from the exhaust gas can be treated, and an increase in cost can be suppressed.

It is the schematic which shows the engine provided with the EGR system of one Embodiment of this invention. It is a schematic sectional drawing which shows the collection part and vaporization part of the EGR system of one Embodiment of this invention.

  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 FIGS. 1 and 2, 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 removed from the engine 10. Return to the intake side.

  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. The condensed water discharge device 20 includes a collection unit 21, a drain pipe 22, a storage unit 23, and a vaporization unit 24.

  As shown in FIG. 2, 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 part 21 has slopes 21a and 21b formed on the inner surface of the lower wall body of the EGR pipe 2 extending in a substantially horizontal direction. The slopes 21a and 21b have a first slope 21a that slopes downward as it goes downstream, and a second slope 21b that slopes upward as it goes downstream. Between the 1st slope 21a and the 2nd slope 21b, the opening part 21c is provided in the lowest position.

  One end side of the drain pipe 22 is connected to the opening 21 c of the collection part 21, and the other end side of the drain pipe 22 is inserted into the intake pipe 13. The drain pipe 22 penetrates the pipe wall of the intake pipe 13 and is inserted into the intake pipe 13. The drain pipe 22 connects the collection part 21 and the storage part 23 in the intake pipe 13.

  The storage portion 23 has a tubular shape and is accommodated in the intake pipe 13. The reservoir 23 extends along the longitudinal direction of the intake pipe 13. The storage part 23 and the intake pipe 13 are arranged to form a double pipe structure, and the storage part 23 as an inner pipe is arranged in the intake pipe 13 as an outer pipe. The reservoir 23 is disposed at the center of the intake pipe 13 in a cross section orthogonal to the longitudinal direction of the intake pipe 13.

  The reservoir 23 is disposed in the intake pipe 13 between the intercooler 15 and the EGR junction 13a. The other end side of the drain pipe 22 is connected to an opening provided on the side wall of the storage unit 23. The reservoir 23 is supported by a drain pipe 22 that passes through the intake pipe 13 and is fixed to the intake pipe 13.

  Both end portions 23a, 23b in the longitudinal direction of the storage portion 23 are closed, and the condensed water can be stored inside. The tube wall of the reservoir 23 is provided with a plurality of through holes (not shown) through which condensed water can pass, and the condensed water in the reservoir 23 can pass to the outer surface side.

  The vaporizing unit 24 includes a plurality of thread-like members 25 that draws and vaporizes condensed water using a capillary phenomenon. The thread-like member 25 only needs to be able to absorb moisture by using a capillary phenomenon, and may be formed by twisting fibers, or may be formed by twisting metal wires or the like. The vaporizing section 24 may be formed by bundling a plurality of linear members.

  The vaporization part 24 is formed over substantially the entire outer surface of the side wall of the tubular storage part 23. The thread member 25 extends radially from the reservoir 23. The tip of the thread-like member 25 extends toward the inner wall surface of the intake pipe 13. The base end portion of the thread-like member 25 is embedded and installed in, for example, a through hole of the storage portion 23.

  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 moisture in the gas is condensed to become condensed water. The condensed water flows on the slopes 21 a and 21 b of the collection unit 21 and flows into the opening 21 c of the collection unit 21. The condensed water introduced into the drain pipe 22 through the opening 21c of the collection part 21 flows through the pipe and is introduced into the tubular storage part 23 of the intake pipe 13 and stored. The condensed water stored in the storage part 23 oozes out to the outer surface side through the through hole. At this time, condensed water is sucked by the capillary phenomenon of the thread-like member embedded in the through hole and guided to the tip side of the thread-like member 25.

  Since the thread-like member 25 is disposed in the fresh air flowing in the intake pipe 13, the condensed water sucked by the thread-like member 25 is exposed to the air stream to be vaporized and supplied to the engine body 10a together with the fresh air for combustion. Is done.

  As described above, according to the EGR system 1 of the present embodiment, the condensed water stored in the storage unit 23 is sucked and vaporized using the capillary phenomenon, so a control valve for controlling the drainage of the condensed water, There is no need to provide a water level sensor for detecting the water level of the condensed water in the reservoir 23. As a result, the apparatus can be simplified, and the manufacturing cost and the maintenance cost can be reduced.

  Further, in the EGR system 1, the condensed water is sucked using the capillary phenomenon, so that the condensed water can be continuously discharged and vaporized. Moreover, in the EGR system 1, the motive power at the time of discharging condensed water can be made unnecessary.

  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.

  Further, in the EGR system 1, a plurality of thread-like members 25 are provided on the outer surface of the storage portion 23, and the thread-like members 25 are disposed inside the intake pipe 13. Is quickly vaporized by dry fresh 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.

  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 above-described embodiment, the vaporizing unit 24 is arranged upstream of the EGR merging unit in the intake pipe 13, but the location where the vaporizing unit 24 is arranged may be another position. For example, in the intake pipe 13, the vaporization section 24 disposed downstream of the EGR merging section 13 a may be used, or the vaporization section 24 may be disposed in the exhaust pipe 14. Further, the vaporizer 24 may be arranged so as to be exposed to the outside air.

  Further, although the thread-like member 25 is arranged on the outer surface side from the through hole of the storage part 23, the thread-like member (string-like member) 25 may be continuously arranged from the inside of the storage part 23. Moreover, what produces a capillary phenomenon is not limited to the thread-like member 25, The some linear member arrange | positioned so that a predetermined clearance may be formed may be sufficient. Moreover, you may draw in condensed water using a cloth-shaped member. Moreover, you may draw in condensed water using a capillary phenomenon by accommodating a granular material in a pipe | tube.

  Moreover, the tubular storage part 23 is not limited to what is arrange | positioned along the longitudinal direction of the intake pipe 13 which is an outer pipe, The storage part 23 is arrange | positioned so that it may cross | intersect with respect to the flow of gas. The vaporizing section 24 may be provided on the outer surface of the storage section 23.

  Moreover, the storage part 23 is not limited to a tubular thing, The thing of another shape may be sufficient. For example, a rectangular tank-shaped reservoir may be used. In the above embodiment, the storage portion 23 is disposed in the intake pipe 13. For example, the storage portion 23 is disposed on the outer surface of the intake pipe 13, and a through hole is provided in the tube wall of the intake pipe 13. You may arrange | position so that the thread-like member 25 may be inserted in the inside of the intake pipe 13 from the surface side. The thread-like member 25 that is the vaporizing section 24 may be arranged on the pipe wall so as to project into the pipe.

  DESCRIPTION OF SYMBOLS 1 ... EGR system, 2 ... EGR piping, 3 ... EGR cooler, 4 ... EGR valve, 10 ... Engine, 10a ... Engine main body, 13 ... Intake pipe, 13a ... EGR merge part, 14 ... Exhaust pipe, 20 ... Condensate discharge Apparatus, 21 ... collection part, 21a, 21b ... slope, 21c ... opening, 22 ... drainage pipe, 23 ... storage part, 24 ... vaporization part, 25 ... thread-like member.

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 reservoir for storing condensed water separated from the exhaust gas flowing through the EGR pipe;
A vaporization unit that sucks and vaporizes the condensed water stored in the storage unit using a capillary phenomenon ;
An outer tube through which gas flows;
An EGR system comprising: an inner tube that is a tubular storage portion disposed along a direction in which the outer tube extends inside the outer tube . An EGR cooler provided in the EGR pipe for cooling the exhaust gas;
A collection unit that is provided downstream of the EGR cooler and collects the condensed water;
A drain pipe connected to the storage section and draining the condensed water collected by the collection section to the outside of the EGR pipe,
The storage part is provided with a through hole for leading the condensed water to the outer surface side of the storage part,
The vaporizing part has a thread-like member as a member for utilizing the capillary phenomenon,
The EGR system according to claim 1 , wherein the filamentary member is disposed from the through hole to an outer surface side of the storage portion. 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 reservoir for storing condensed water separated from the exhaust gas flowing through the EGR pipe;
  A vaporization unit that sucks and vaporizes the condensed water stored in the storage unit using capillary action;
An EGR cooler provided in the EGR pipe for cooling the exhaust gas;
A collection unit that is provided downstream of the EGR cooler and collects the condensed water;
A drain pipe connected to the storage section and draining the condensed water collected by the collection section to the outside of the EGR pipe,
The storage part is provided with a through hole for leading the condensed water to the outer surface side of the storage part,
The vaporizing part has a thread-like member as a member for utilizing the capillary phenomenon,
The said thread-like member is an EGR system arrange | positioned from the said through-hole to the outer surface side of the said storage part. The EGR pipe is provided with an EGR valve upstream of an EGR merging portion that is a merging portion with the intake pipe on the intake side,
The collection part has a slope between the EGR cooler and the EGR valve,
The EGR system according to claim 2 , wherein the vaporizing unit is disposed upstream of the EGR merging unit of the intake pipe.

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