JP2008285997A - Exhaust gas treatment device of engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust gas treatment device of an engine capable of preventing inconvenience from occurring in a purification treatment of an exhaust gas as much as possible while further efficiently recovering heat from the exhaust gas. <P>SOLUTION: A cylinder block is provided with a block-side passage being an exhaust gas passage. The downstream-side end of the block-side passage in an exhaust gas flow direction is connected to a position of a gas passage other than a position between an exhaust manifold and a purification treatment part. A part of the exhaust gas exhausted from an exhaust port is delivered to the block-side passage. When the exhaust gas passes through the block-side passage, the cylinder block is directly heated by the heat of the exhaust gas. Thereby the cylinder block is warmed up well. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an engine exhaust gas treatment apparatus.

  Various devices of this type that can recover heat from engine exhaust gas are known.

  For example, in an exhaust heat recovery system disclosed in Japanese Patent Application Laid-Open No. 2006-77741 (Patent Document 1), an exhaust heat recovery heat exchanger is connected to an exhaust pipe. A heater hot water flow path is connected to the heat exchanger. A front heater core is disposed at a position between the engine and the heat exchanger in the heater hot water flow path.

  In this exhaust heat recovery system, the heat of the cooling water (hot water) that has become high temperature through the engine is used for heating by heat exchange in the front heater core. The cooling water lowered in temperature by the heat exchange flows through the heat exchanger after being discharged from the front heater core. At this time, the exhaust gas introduced into the heat exchanger and the cooling water exchange heat. That is, the exhaust gas is cooled. Thereby, the silencing effect of the exhaust system can be obtained.

  A cooling water heater device for an internal combustion engine disclosed in Japanese Unexamined Patent Publication No. 2000-240510 (Patent Document 2) includes an exhaust gas recirculation passage, a heater passage, and a heat exchanger. The exhaust gas recirculation passage is provided to communicate the exhaust passage and the intake passage. The heater passage is provided so as to communicate the outlet side of the water jacket and the inlet side of the heater core. The heat exchanger is configured to exchange heat between exhaust gas flowing through the exhaust gas recirculation passage and cooling water flowing through the heater passage.

  According to this configuration, the amount of heat of the exhaust gas recirculated from the exhaust passage to the intake passage is transmitted to the cooling water flowing through the heater passage. Thereby, the temperature of the cooling water is quickly raised.

  An engine warm-up device disclosed in Japanese Patent Application Laid-Open No. 2004-108256 (Patent Document 3) has the following configuration. An exhaust pipe is connected to an exhaust manifold provided on the exhaust side of the engine. A catalytic converter is interposed in the exhaust pipe. A passage through which exhaust gas passes is formed in a cylinder block provided therein with a cooling water passage through which the engine cooling water passes.

  Here, the exhaust gas inlet in the passage communicates with the exhaust manifold. On the other hand, the outlet of the exhaust gas in the passage communicates with a portion of the exhaust pipe upstream of the catalytic converter. The passage is provided along the cooling water channel.

In such a configuration, when the engine is cold-started, the cylinder block is directly heated from the inside by the heat of the exhaust gas passing through the passage in the cylinder block, and the cooling through the cooling water passage is performed. Water is heated.
Japanese Patent Laid-Open No. 2006-77741 JP 2000-240510 A JP 2004-108256 A

  However, an exhaust heat recovery system disclosed in Japanese Patent Application Laid-Open No. 2006-77741 (Patent Document 1) and a cooling water heater device for an internal combustion engine disclosed in Japanese Patent Application Laid-Open No. 2000-240510 (Patent Document 2). The heat is recovered from the exhaust gas using heat exchange between the exhaust gas and the cooling water. For this reason, the recovery efficiency in such a configuration is not very good.

  On the other hand, in the engine warm-up device disclosed in Japanese Patent Application Laid-Open No. 2004-108256 (Patent Document 3), the cylinder block is directly heated from the inside by the heat of the exhaust gas. The efficiency of is good. However, in such a configuration, the exhaust gas cooled by heat recovery returns to the exhaust pipe and reaches the catalytic converter. For this reason, there exists a possibility that the warming-up effect of the said catalytic converter may fall. In particular, inconvenience can occur when it is desired to supply the exhaust gas having a relatively high temperature to the catalytic converter in order to perform a regeneration process for oxidizing the carbon particles collected by the catalytic converter. That is, inconvenience may occur in the exhaust gas purification process.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to purify the exhaust gas while recovering heat from the exhaust gas (waste heat recovery) more efficiently. It is an object of the present invention to provide an engine exhaust gas processing apparatus that can suppress inconvenience as much as possible.

  An engine exhaust gas treatment device (hereinafter simply referred to as “exhaust gas treatment device”) according to the present invention includes a cylinder head, a cylinder block, an intake passage, an exhaust passage, and a purification treatment section. Yes.

  The cylinder head is formed with an intake port and an exhaust port. The intake passage is connected to the intake port. The exhaust passage is connected to the exhaust port. The exhaust passage may include an exhaust manifold and an exhaust pipe. That is, the exhaust manifold is connected to the exhaust port. The exhaust pipe is connected to the exhaust manifold.

  The said purification process part is comprised so that the exhaust gas discharged | emitted from the said exhaust port can be purified. Typically, a catalytic converter can be used as the purification processing unit. The purification processing unit is interposed in the exhaust passage (the exhaust pipe).

  The cylinder block is joined to the cylinder head. The cylinder block is provided with a block side passage which is a passage for the exhaust gas. Specifically, the block side passage may be provided in the cylinder block, for example. Or the said block side channel | path may be mounted | worn with the said cylinder block so that the outer wall of the said cylinder block may be touched, for example.

  A feature of the present invention is that the downstream end of the block side passage in the flow direction of the exhaust gas (hereinafter referred to as the exhaust gas flow direction) is the exhaust manifold and the purification processing section in the gas flow path. Is connected to a position other than the position between.

  Specifically, for example, the end portion of the block side passage may be connected to the intake passage as the gas flow path. In other words, the block side passage may be provided as an EGR passage connecting the exhaust passage and the intake passage. That is, the EGR passage may include the block side passage. Here, EGR (exhaust gas recirculation) means that a part of the exhaust gas is recirculated to the intake air in order to suppress the combustion temperature and suppress the generation of NOx.

  In the exhaust gas processing apparatus of the present invention having such a configuration, a part of the exhaust gas discharged from the exhaust port is sent from the exhaust passage (the exhaust manifold or the exhaust pipe) to the block side passage. When the exhaust gas passes through the block side passage, the cylinder block is directly warmed by the heat of the exhaust gas. Thereby, the said cylinder block is warmed up favorably.

  Here, when the exhaust gas whose temperature has been reduced by warming up the cylinder block is returned to the exhaust passage (the exhaust pipe) immediately before the purification processing unit, the warming of the purification processing unit The machine effect may be reduced. However, in the exhaust gas treatment device of the present invention, the exhaust gas whose temperature has been lowered is other than immediately before the purification treatment unit in the gas flow path (this includes the intake passage and the exhaust passage). Returned to the place. Therefore, it can be suppressed as much as possible that the warming-up effect of the said purification process part is impaired.

  As described above, according to the exhaust gas treatment device of the present invention, heat recovery from the exhaust gas (waste heat recovery) can be performed more efficiently, and inconvenience can be caused in the exhaust gas purification process. It can be suppressed as much as possible.

  The exhaust gas processing device may further include a switching valve. The switching valve is configured to be able to switch whether or not the exhaust gas is introduced into the block side passage.

  In such a configuration, whether or not the exhaust gas is introduced into the block-side passage is switched by the switching valve in accordance with an operating state (a warm-up state of the cylinder block). Thereby, the introduction of the exhaust gas into the block side passage can be appropriately performed according to the operating state.

  The exhaust gas treatment device may be configured as follows: the EGR passage includes an out-block passage different from the block-side passage. An EGR switching valve (as the switching valve) is interposed in the EGR passage. The EGR switching valve is configured to be able to switch the usage state of the outside-block passage and the block-side passage.

  In such a configuration, the use state of the outside-block passage and the block-side passage is switched by the EGR switching valve in accordance with the operating state (warming-up state of the cylinder block). Thereby, the introduction of the exhaust gas into the block side passage and the implementation of EGR can be appropriately performed according to the operating state.

  The exhaust gas treatment device may be configured as follows: The exhaust gas treatment device further includes a turbocharger, a low pressure loop outlet tube, and a low pressure loop introduction tube. The turbocharger is interposed in the exhaust passage between the cylinder head and the purification processing unit. The turbocharger is interposed in the intake passage. The low-pressure loop introduction pipe and the low-pressure loop lead-out pipe are exhaust gas passages that constitute the EGR passage. The low-pressure loop outlet pipe is provided so as to branch from the exhaust passage at a position downstream of the purification processing portion in the exhaust gas flow direction. The low-pressure loop outlet pipe is connected to the upstream end of the block side passage in the exhaust gas flow direction. The low-pressure loop introduction pipe is provided so as to join the intake passage at a position upstream of the turbocharger in the intake air flow direction. The low-pressure loop introduction pipe is connected to the downstream end of the block side passage in the exhaust gas flow direction.

  In such a configuration, a part of the exhaust gas in the exhaust passage is led out to the low-pressure loop outlet pipe at a position downstream of the purification processing portion in the exhaust gas flow direction. The exhaust gas is supplied to the block side passage through the low pressure loop outlet pipe. When the exhaust gas passes through the block side passage, the cylinder block is warmed up well by the heat of the exhaust gas.

  The exhaust gas supplied to the block side passage is introduced into the intake passage through the low pressure loop introduction pipe. The exhaust gas is introduced into the intake passage at a low pressure portion in the intake passage, that is, at a position upstream of the turbocharger in the intake air flow direction.

  The exhaust gas treatment device may be configured as follows: The exhaust gas treatment device further includes the turbocharger, a high-pressure loop lead-out pipe, and a high-pressure loop introduction pipe. The high-pressure loop introduction pipe and the high-pressure loop lead-out pipe are exhaust gas passages that constitute the EGR passage. The high-pressure loop outlet pipe is provided so as to branch from the exhaust passage at a position between the cylinder head and the turbocharger. The high-pressure loop outlet pipe is connected to the upstream end of the block side passage in the exhaust gas flow direction. The high-pressure loop introduction pipe is provided so as to merge with the intake passage at a position between the turbocharger and the cylinder head. The high-pressure loop introduction pipe is connected to the downstream end of the block side passage in the exhaust gas flow direction.

  In such a configuration, a part of the exhaust gas in the exhaust passage is led out to the high-pressure loop outlet pipe at a position between the cylinder head and the turbocharger. The exhaust gas is supplied to the block side passage through the high-pressure loop outlet pipe. When the exhaust gas passes through the block side passage, the cylinder block can be warmed up well by the heat of the exhaust gas.

  The exhaust gas supplied to the block side passage is introduced into the intake passage through the high pressure loop introduction pipe. The exhaust gas is introduced into the intake passage at a high pressure portion in the intake passage, that is, at a position between the turbocharger and the cylinder head.

  The exhaust gas processing device may be configured to be able to switch between the following two modes related to introduction of the exhaust gas into the intake passage: (1) the low-pressure loop outlet pipe, the block-side passage, and Introduction of the exhaust gas into the intake passage through the low pressure loop introduction pipe; (2) intake air of the exhaust gas through the high pressure loop outlet pipe, the block side passage, and the high pressure loop introduction pipe. Introduction to the aisle.

  According to such a configuration, introduction of the exhaust gas into the block-side passage and execution of EGR can be performed more appropriately according to the operating state.

  The block side passage may be provided at a position corresponding to a lower portion of the cylinder. Thereby, the lower part of the cylinder (which is a part that is relatively slow because it is relatively far from the combustion chamber) can be satisfactorily warmed by the exhaust gas.

  Fins may be provided on the inner wall of the block side passage. This fin may be preferably provided on the inner wall on the side close to the cylinder.

  According to such a configuration, the heat of the exhaust gas supplied to the block side passage can be efficiently recovered by the fins. Therefore, the cylinder block can be better warmed up by the heat of the exhaust gas.

  The material constituting the inner wall surface of the block side passage close to the piston may be configured to have higher thermal conductivity than the material constituting the inner wall surface on the opposite side.

  According to this configuration, the heat of the exhaust gas can be efficiently recovered by the inner wall surface of the block side passage on the side close to the piston. Therefore, the inner wall surface of the cylinder facing the piston in the cylinder block can be warmed up better by the heat of the exhaust gas.

  Hereinafter, embodiments of the present invention (embodiments that the applicant considers best at the time of filing of the present application) will be described with reference to the drawings.

<Configuration of Exhaust Gas Treatment System of Embodiment>
FIG. 1 is a schematic diagram showing the overall configuration of an exhaust gas treatment system 1 according to an embodiment of the present invention.

  The exhaust gas treatment system 1 includes an engine 2, an intake passage 3, an exhaust passage 4, and an EGR passage 5. The exhaust gas processing system 1 (particularly, the intake passage 3, the exhaust passage 4, and the EGR passage 5) is provided with various types of auxiliary equipment (to be described later) for performing appropriate processing on intake air or exhaust gas ( Valve, cooler, supercharger, filter, etc.).

<< Schematic configuration of engine >>
FIG. 2 is a side sectional view of the engine 2 shown in FIG.

  Referring to FIG. 2, the cylinder head 21 is provided with an intake port 21a and an exhaust port 21b. The intake port 21a is formed such that its end portion communicates with the combustion chamber CC. The end portion of the intake port 21a is opened and closed by an intake valve 21c. The exhaust port 21b is formed so that its start end communicates with the combustion chamber CC. The start end of the exhaust port 21b is opened and closed by an exhaust valve 21d.

  Further, the cylinder head 21 is formed with an upper water jacket 21e that is a flow path of the cooling water. The upper water jacket 21e is provided in the vicinity of the intake port 21a, in the vicinity of the exhaust port 21b, and between the intake port 21a and the exhaust port 21b.

  A cylinder block 22 is joined to the lower end of the cylinder head 21 (in FIG. 1, the cylinder head 21 and the cylinder block 22 are connected for convenience of explanation of processing of intake air or exhaust gas described later. It is shown in a separated state.)

  The cylinder block 22 is formed with a cylinder 22a, a lower water jacket 22b, and an in-block exhaust passage 22c. The cylinder 22 a is formed by the inner cylindrical surface of the cylinder liner 23. The cylinder liner 23 is a thin cylindrical member and is accommodated in the cylinder block 22. A piston 24 is accommodated in the cylinder 22a (inside the cylinder liner 23) so as to be reciprocally movable in the vertical direction in the figure. A lower water jacket 22b that is a flow path of the cooling water is formed so as to surround an upper portion of the cylinder 22a (cylinder liner 23).

  The in-block exhaust passage 22 c as the block side passage of the present invention is an exhaust gas passage formed inside the cylinder block 22. The in-block exhaust passage 22c is provided below the lower water jacket 22b so as to surround the cylinder 22a. That is, the in-block exhaust passage 22c is provided at a position corresponding to a relatively lower part of the cylinder 22a.

  The cylinder head 21 and the cylinder block 22 are joined via a gasket 25. The gasket 25 is formed with a through hole 25a. The through hole 25a is formed to connect the upper water jacket 21e and the lower water jacket 22b.

<< Intake and exhaust system configuration >>
Referring again to FIG. 1, the intake passage 3 includes an intake manifold 31, a high pressure side intake pipe 32, and a low pressure side intake pipe 33. The low pressure side intake pipe 33, the high pressure side intake pipe 32, and the intake manifold 31 are arranged in this order from the upstream side to the downstream side in the flow direction of the intake air. The start end of the intake manifold 31 is connected to the high-pressure side intake pipe 32. The end of the intake manifold 31 is connected to the start end of the intake port 21a (see FIG. 2).

  The exhaust passage 4 includes an exhaust manifold 41, a high pressure side exhaust pipe 42, a low pressure side exhaust pipe 43, and a downstream side exhaust pipe 44. The exhaust manifold 41, the high-pressure side exhaust pipe 42, the low-pressure side exhaust pipe 43, and the downstream side exhaust pipe 44 are arranged in this order from the upstream side to the downstream side in the exhaust gas flow direction (exhaust gas flow direction). Yes. The start end of the exhaust manifold 41 is connected to the end of the exhaust port 21b (see FIG. 2). A terminal portion of the exhaust manifold 41 is connected to the high-pressure side exhaust pipe 42.

<<<< EGR passage >>>>
The EGR passage 5 is an exhaust gas passage and is provided so as to connect the exhaust passage 4 and the intake passage 3. That is, the EGR passage 5 is configured such that a part of the exhaust gas discharged from the exhaust port 21b (see FIG. 2) to the exhaust manifold 41 can be introduced into the intake passage 3.

  The EGR passage 5 in the present embodiment includes an exhaust outlet pipe 51, an outer block passage 52, a block inlet pipe 53, a block outlet pipe 54, and an exhaust inlet pipe 55.

  One end of the exhaust outlet pipe 51 is connected to the exhaust manifold 41. One end of the outside block passage 52 and one end of the block introduction pipe 53 are connected to the other end of the exhaust outlet pipe 51. That is, the outer block passage 52 and the block introduction pipe 53 are provided so as to branch from the exhaust outlet pipe 51.

  The other end of the block introduction pipe 53 is connected to an exhaust gas inlet in the in-block exhaust passage 22c. The exhaust gas outlet in the in-block exhaust passage 22 c is connected to one end of the block outlet pipe 54. The other end of the block outlet pipe 54 is connected to one end of the exhaust introduction pipe 55. Further, the other end portion of the outside block passage 52 is connected to the one end portion of the exhaust introduction pipe 55. In other words, the one end of the exhaust introduction pipe 55 is connected to the junction of the block outlet pipe 54 and the outside block passage 52. The other end of the exhaust introduction pipe 55 is connected to the intake manifold 31.

  Thus, in the present embodiment, the EGR passage 5 includes the in-block exhaust passage 22c. An exhaust gas outlet in the in-block exhaust passage 22c, that is, an end portion on the downstream side in the exhaust gas flow direction of the in-block exhaust passage 22c is connected to the intake passage 3 ( It is connected to the intake manifold 31).

  Note that the exhaust outlet pipe 51 and the block inlet pipe 53 in this embodiment correspond to the high-pressure loop outlet pipe of the present invention. That is, the exhaust outlet pipe 51 is provided so as to branch from the exhaust passage 4 at a position between the cylinder head 21 and a turbocharger 63 described later. The block introduction pipe 53 is connected to the upstream end of the in-block exhaust passage 22c in the exhaust gas flow direction. The exhaust outlet pipe 51 and the block introduction pipe 53 are connected via an EGR switching valve 67 described later.

  Further, the block outlet pipe 54 and the exhaust introduction pipe 55 in the present embodiment correspond to the high-pressure loop introduction pipe of the present invention. That is, the exhaust introduction pipe 55 is provided so as to merge with the intake passage 3 at a position between the cylinder head 21 and a turbocharger 63 described later. The block outlet pipe 54 is connected to the downstream end of the in-block exhaust passage 22c in the exhaust gas flow direction. The block outlet pipe 54 and the exhaust introduction pipe 55 are connected to each other.

<<< Auxiliary machinery >>>
As described above, in the intake passage 3, the exhaust passage 4, and the EGR passage 5, various auxiliary machines (air filter 61, throttle valve 62...) Are interposed.

  The air filter 61 is interposed in the low pressure side intake pipe 33. The throttle valve 62 is interposed in the high pressure side intake pipe 32.

  The turbocharger 63 described above includes a turbine part 63a and a compressor part 63b. The exhaust gas inlet in the turbine part 63a is connected to the high-pressure side exhaust pipe. The exhaust gas outlet in the turbine part 63 a is connected to the low pressure side exhaust pipe 43. An intake air inlet in the compressor unit 63 b is connected to the low-pressure side intake pipe 33. An intake air outlet in the compressor unit 63b is connected to the high-pressure side intake pipe 32. That is, the turbocharger 63 is interposed in the intake passage 3 and is interposed in the exhaust passage 4 at a position between the cylinder head 21 and the catalyst device 64.

  The catalyst device 64 as the purification processing unit of the present invention is configured to purify the exhaust gas discharged from the exhaust port 21b (see FIG. 2). Specifically, the catalyst device 64 of the present embodiment is configured to have a function as a so-called three-way catalytic converter and a function as a so-called particle filter.

  The EGR cooler 65 is interposed in the outside-block passage 52. The EGR valve 66 is an open / close valve and is interposed in the exhaust introduction pipe 55.

  The above-described EGR switching valve 67 as a switching valve of the present invention is a three-way valve, and is interposed at a portion where the outside block passage 52 and the block introduction pipe 53 branch from the exhaust outlet pipe 51. The EGR switching valve 67 is configured to be able to switch the usage state of the outside-block passage 52 and the inside-block exhaust passage 22c. That is, the EGR switching valve 67 is configured to be able to switch between introduction of exhaust gas into the in-block exhaust passage 22c and introduction of exhaust gas into the outside-block passage 52.

<Operation of Exhaust Gas Treatment System of Embodiment>
Next, the operation of the exhaust gas processing system 1 of the present embodiment having the above-described configuration will be described with reference to FIGS.

  The intake air filtered by the air filter 61 reaches the compressor section 63b in the turbocharger 63 via the low-pressure side intake pipe 33. The intake air supercharged by the compressor unit 63b reaches the intake manifold 31 via the high-pressure side intake pipe 32 and the throttle valve 62, and is sucked into the combustion chamber CC via the intake port 21a.

  The exhaust gas generated by the combustion of the fuel mixture in the combustion chamber CC is discharged from the cylinder head 21 to the exhaust manifold 41 via the exhaust port 21b. This exhaust gas is sent from the exhaust manifold 41 to the turbine section 63 a in the turbocharger 63 via the high pressure side exhaust pipe 42, and then sent to the catalyst device 64 via the low pressure side exhaust pipe 43. The exhaust gas purified by the catalyst device 64 is sent toward the downstream exhaust pipe 44 and then discharged toward the outside air.

  Here, the EGR valve 66 is opened during EGR. Thereby, a part of the exhaust gas is led out from the exhaust manifold 41 to the exhaust outlet pipe 51 and introduced into the intake manifold 31 via the exhaust inlet pipe 55. Thereby, combustion temperature is suppressed low and the production | generation of NOx is suppressed.

  During the execution of EGR, the communication state of the EGR switching valve 67 is switched according to the warm-up state of the engine 2.

  For example, during the warm-up operation, the exhaust discharge pipe 51 and the block introduction pipe 53 are communicated with each other by the EGR switching valve 67, while the communication between the exhaust discharge pipe 51 and the outside block passage 52 is blocked. As a result, the exhaust gas is introduced into the cylinder block 22 (in-block exhaust passage 22c) via the block introduction pipe 53. Then, the heat of the exhaust gas is transmitted to the cylinder block 22, so that the cylinder block 22 is warmed up satisfactorily. At the same time, the exhaust gas is cooled by the cylinder block 22. That is, the cylinder block 22 functions as an EGR cooler.

  On the other hand, after the warm-up of the engine 2 is completed, the exhaust outlet pipe 51 and the outside block passage 52 are communicated with each other by the EGR switching valve 67, while the exhaust outlet pipe 51 and the block introduction pipe 53 are disconnected. As a result, the exhaust gas flows into the intake manifold 31 through the outside-block passage 52 in which the EGR cooler 65 is interposed.

<Effects of Configuration of Embodiment>
Hereinafter, operations and effects of the configuration of the present embodiment will be described with reference to the drawings.

  In the present embodiment, a part of the exhaust gas is supplied to the in-block exhaust passage 22c which is an exhaust gas passage provided in the cylinder block 22 (inside the cylinder block 22). Then, heat exchange occurs between the cylinder block 22 and the exhaust gas on the inner wall surface of the in-block exhaust passage 22c. That is, when the exhaust gas passes through the in-block exhaust passage 22c, the cylinder block 22 is directly warmed by the heat of the exhaust gas. On the other hand, the exhaust gas is cooled by the cylinder block 22.

  Therefore, according to the configuration of the present embodiment, the cylinder block 22 is warmed up satisfactorily. Further, the heat (waste heat) of the exhaust gas is efficiently recovered. Further, the cylinder block 22 cooled by the lower water jacket 22b functions as an EGR cooler. As a result, the EGR gas is cooled well at the same time as the cylinder block 22 is warmed up.

  Here, when the exhaust gas whose temperature has been lowered by warming up the cylinder block 22 is returned to the low-pressure side exhaust pipe 43 which is the exhaust gas flow path immediately before the catalyst device 64, the catalyst device 64 is warmed up. The effect may be reduced. In particular, in order to supply a relatively high temperature exhaust gas to the catalyst device 64 in order to perform a regeneration process for oxidizing the carbon particles collected by the catalyst device 64, inconvenience may occur.

  However, in this embodiment, the exhaust manifold 41 and the catalyst in the gas (intake air, fuel mixture, or exhaust gas) flow path are downstream ends of the in-block exhaust passage 22c in the exhaust gas flow direction. It is connected to a position other than the position between the device 64. Therefore, the warming-up effect of the catalyst device 64 can be suppressed as much as possible.

  As described above, according to the exhaust gas treatment system 1 of the present embodiment, the heat recovery from the exhaust gas (waste heat recovery) can be performed more efficiently, and inconvenience can be caused in the exhaust gas purification process. It can be suppressed as much as possible.

  In the present embodiment, the in-block exhaust passage 22c is provided below the lower water jacket 22b. That is, the in-block exhaust passage 22c is provided at a position corresponding to a relatively lower part of the cylinder 22a. As a result, the relatively lower part of the cylinder 22a (which is a relatively slow part because it is relatively far from the combustion chamber CC) can be satisfactorily warmed up by the exhaust gas.

  The exhaust gas processing system 1 of the present embodiment is provided with an EGR switching valve 67 for switching whether or not exhaust gas is introduced into the in-block exhaust passage 22c.

  According to such a configuration, whether or not the exhaust gas is introduced into the in-block exhaust passage 22c is switched by the EGR switching valve 67 according to the operating state of the engine 2 (warm-up state of the cylinder block 22). Thereby, the introduction of the exhaust gas into the in-block exhaust passage 22c is appropriately performed according to the operating state of the engine 2.

<List of examples of modification>
Note that, as described above, the above-described embodiment is merely an example of the embodiment of the present invention considered to be the best at the time of filing of the present application by the applicant, and the present invention is not limited to the above. It is not limited to the embodiment. Therefore, as a matter of course, various modifications can be made to the configurations shown in the above-described embodiments without departing from the essential part of the present invention.

  Hereinafter, some modifications will be exemplified. In the following description of each modification, the same name and the same code | symbol shall be attached | subjected about the component which has the structure and function similar to each component in the above-mentioned embodiment also in the said modification. . And about description of the said component, description in the above-mentioned embodiment shall be used suitably in the range which is not inconsistent.

  However, it goes without saying that the modified examples are not limited to the following. The limited interpretation of the present invention based on the description of the above-described embodiment and the following modifications unfairly harms the interests of the applicant (rushes the application under the principle of prior application), but unfairly imitates the imitator. It is not allowed (as opposed to the purpose of patent law for the protection and use of the invention).

  Further, it goes without saying that the configuration of the above-described embodiment and the configuration described in each of the following modifications can be applied in an appropriate combination within a technically consistent range.

  (1) The present invention is applicable regardless of the type of engine such as a gasoline engine or a diesel engine. Moreover, there is no limitation also about a fuel-injection system.

  (2) FIG. 3 is a schematic diagram showing the configuration of one modification of the exhaust gas treatment system 1 shown in FIG. The EGR passage 5 in the exhaust gas treatment system 1 of this modification includes a high-pressure loop pipe 56, a low-pressure loop outlet pipe 57, and a low-pressure loop introduction pipe 58.

  The high-pressure loop pipe 56 is obtained by reconfiguring the exhaust lead-out pipe 51, the block outer passage 52, and the exhaust introduction pipe 55 in the above-described embodiment as a single pipe (the high-pressure loop introduction pipe and the high-pressure loop lead-out pipe of the present invention are the same). To include).

  The low pressure loop outlet pipe 57 is provided so as to branch from the exhaust passage 4 at a position downstream of the catalyst device 64 in the exhaust gas flow direction. The low pressure loop outlet pipe 57 is connected to an upstream end (exhaust gas inlet) of the in-block exhaust passage 22c in the exhaust gas flow direction.

  The low-pressure loop introduction pipe 58 is provided so as to merge with the intake passage 3 at a position upstream of the turbocharger 63 in the intake air flow direction. The low-pressure loop introduction pipe 58 is connected to the downstream end (exhaust gas outlet) of the in-block exhaust passage 22c in the exhaust gas flow direction.

  That is, in the present modification, the exhaust gas inlet of the in-block exhaust passage 22 c is connected to the downstream exhaust pipe 44 via the low pressure loop outlet pipe 57. Further, the exhaust gas outlet of the intra-block exhaust passage 22 c is connected to the low pressure side intake pipe 33 via the low pressure loop introduction pipe 58.

  In this modification, throttle valves 62a and 62b are provided. The throttle valve 62 a is interposed between the turbocharger 63 and the intake manifold 31. The throttle valve 62 b is interposed between the air filter 61 and the turbocharger 63.

  In this modification, unlike the above-described embodiment, an EGR cooler 65 is interposed in the low-pressure loop outlet pipe 57. Further, in this modification, a high pressure EGR valve 68, an exhaust introduction switching valve 69a, and a low pressure EGR switching valve 69b are provided.

  Similar to the EGR valve 66 in the above-described embodiment, the high-pressure EGR valve 68 is an open / close valve and is interposed in the high-pressure loop pipe 56. The exhaust introduction switching valve 69 a is a three-way valve, and is interposed at a connection portion between the downstream exhaust pipe 44 and the low-pressure loop outlet pipe 57. The low pressure EGR switching valve 69 b is an open / close valve, and is interposed in the low pressure loop introduction pipe 58.

  As described above, the exhaust gas treatment system 1 of the present modification includes the high-pressure loop EGR (HPL-EGR) mechanism and the low-pressure loop EGR (LPL-EGR) mechanism. The in-block exhaust passage 22c is included on the low pressure loop side. On the other hand, the exhaust gas treatment system 1 in the above-described embodiment includes only the high-pressure loop EGR, and the in-block exhaust passage 22c is included in the high-pressure loop EGR.

  In such a configuration, when the high-pressure EGR valve 68 is opened, a part of the exhaust gas in the exhaust manifold 41 is led to the high-pressure loop pipe 56. Then, the exhaust gas led out to the high-pressure loop pipe 56 is introduced into the intake manifold 31 which is a high-pressure portion in the intake passage 3. In this way, the high-pressure loop EGR is performed. On the other hand, when the high pressure EGR valve 68 is closed, the high pressure loop EGR is not performed.

  Further, when the downstream exhaust pipe 44 and the low-pressure loop outlet pipe 57 are communicated with each other by the exhaust introduction switching valve 69a and the low-pressure EGR switching valve 69b is opened, the exhaust gas that has passed through the catalyst device 64 is passed through the low-pressure loop outlet pipe 57a. 57 is introduced into the cylinder block 22 (in-block exhaust passage 22c). Then, the exhaust gas that has passed through the in-block exhaust passage 22 c is introduced into the low pressure side intake pipe 33 that is a low pressure portion in the exhaust passage 4. Thereby, the low pressure loop EGR is performed. On the other hand, when the communication between the downstream exhaust pipe 44 and the low pressure loop outlet pipe 57 is blocked by the exhaust introduction switching valve 69a and the low pressure EGR switching valve 69b is closed, the low pressure loop EGR is not performed.

  In this way, the high pressure EGR valve 68 controls the state of execution of the high pressure loop EGR. On the other hand, the implementation state of the low pressure loop EGR is controlled by the exhaust introduction switching valve 69a and the low pressure EGR switching valve 69b.

  Here, in the present modification, switching between the high-pressure loop EGR and the low-pressure loop EGR and whether or not the cooling water is supplied to the EGR cooler 65 are appropriately performed according to the operating state of the engine 2. According to such a configuration, introduction of the exhaust gas into the block-side passage and execution of EGR can be performed more appropriately according to the operating state.

  For example, while the low pressure loop EGR is being performed and the engine 2 is warmed up, the supply of the cooling water to the EGR cooler 65 is stopped. Thereby, it is suppressed as much as possible that the heat | fever of the EGR gas in the low pressure loop EGR is taken by the EGR cooler 65. Then, the heat of the EGR gas is efficiently absorbed by the cylinder block 22. Therefore, the cylinder block 22 is warmed up by absorbing the waste heat from the EGR gas and the EGR gas is efficiently cooled.

  On the other hand, during the execution of the low pressure loop EGR and after the warm-up of the engine 2 is finished, the cooling water is supplied to the EGR cooler 65. As a result, the EGR gas in the low pressure loop EGR is sufficiently cooled by the EGR cooler 65, and the amount of heat transfer from the EGR gas to the cylinder block 22 in the in-block exhaust passage 22c is effectively suppressed.

  In the exhaust gas treatment system 1 of this modification, a high pressure loop EGR mechanism and a low pressure loop EGR mechanism are provided, and the in-block exhaust passage 22c is included on the low pressure loop side. However, the present invention is not limited to this. That is, for example, the in-block exhaust passage 22c may be included on the high-pressure loop side.

  (3) FIG. 4 is a schematic diagram showing the configuration of another modification of the exhaust gas treatment system 1 shown in FIG. The exhaust gas treatment system 1 of this modified example has a configuration in which the configuration of the above-described embodiment (see FIG. 1) and the configuration of the above-described modified example (see FIG. 3) are combined.

  The EGR passage 5 in the exhaust gas processing system 1 of the present modification includes a high-pressure loop pipe 56, a low-pressure loop outlet pipe 57, a low-pressure loop introduction pipe 58, and a high-pressure side bypass pipe 59.

  In the present modification, the high-pressure loop pipe 56 is provided so as to connect the intake manifold 31 and the exhaust manifold 41. In the middle of the high-pressure loop pipe 56, a cylinder block 22 (in-block exhaust passage 22c) is connected.

  The configurations of the low-pressure loop lead-out pipe 57 and the low-pressure loop introduction pipe 58 are the same as those of the above-described modification (see FIG. 3). That is, the low-pressure loop outlet pipe 57 is provided so as to branch from the downstream side exhaust pipe 44 and to be connected to the cylinder block 22 (in-block exhaust passage 22c). The low pressure loop introduction pipe 58 is provided so as to connect the cylinder block 22 and the low pressure side intake pipe 33.

  The high-pressure side bypass pipe 59 includes a portion on the upstream side in the exhaust gas flow direction with respect to the cylinder block 22 of the high-pressure loop pipe 56 and a portion on the downstream side in the exhaust gas flow direction with respect to the cylinder block 22 of the high-pressure loop pipe 56. , Are provided to connect. That is, the high pressure side bypass pipe 59 is provided so as to bypass the cylinder block 22.

  Also in the present modification, a throttle valve 62a, a throttle valve 62b, an exhaust introduction switching valve 69a, and a low-pressure EGR switching valve 69b are provided as in the above-described modification (see FIG. 3).

  A portion of the high-pressure loop pipe 56 on the downstream side of the cylinder block 22 in the exhaust gas flow direction and in the vicinity of the joining position with the intake manifold 31 is provided with a high-pressure EGR valve 68a composed of an on-off valve. It is disguised. Further, a bypass switching valve 68b composed of a three-way valve is interposed at a connection portion between a portion of the high-pressure loop pipe 56 upstream of the cylinder block 22 in the exhaust gas flow direction and the high-pressure side bypass pipe 59. Yes.

  As described above, the exhaust gas treatment system 1 of the present modification includes the low pressure loop EGR and the high pressure of the first mode by the high pressure EGR valve 68a, the bypass switching valve 68b, the exhaust introduction switching valve 69a, and the low pressure EGR switching valve 69b. The loop EGR and the high-pressure loop EGR of the second aspect can be switched.

  Here, the low pressure loop EGR is introduction of exhaust gas into the intake passage 3 (low pressure side intake pipe 33) via the low pressure loop outlet pipe 57, the in-block exhaust passage 22c, and the low pressure loop introduction pipe 58. . The high-pressure loop EGR of the first aspect is introduction of exhaust gas into the intake passage 3 (intake manifold 31) via the high-pressure loop pipe 56 and the in-block exhaust passage 22c. Further, the high pressure loop EGR of the second aspect is the intake of exhaust gas via the high pressure loop pipe 56 and the high pressure side bypass pipe 59 (bypassing the in-block exhaust passage 22c by the high pressure side bypass pipe 59). It is introduction into the passage 3.

  According to such a configuration, introduction of exhaust gas into the cylinder block 22 (in-block exhaust passage 22c) and execution of EGR can be performed more appropriately according to the operating state.

  (4) FIGS. 5 to 8 are enlarged side sectional views showing a specific example of the internal configuration of the in-block exhaust passage 22c shown in FIG.

  As shown in FIG. 5, fins 221 may be provided on the inner wall of the in-block exhaust passage 22c. As shown in FIG. 5, the fins 221 are preferably provided on the inner wall on the side close to the cylinder liner 23 (the side close to the cylinder 22a in FIG. 2).

  According to such a configuration, the heat of the exhaust gas supplied to the in-block exhaust passage 22 c can be efficiently recovered by the fins 221. Therefore, the cylinder block 22 can be better warmed up by the heat of the exhaust gas.

  Referring to FIG. 6, the heat conducting member 222 constituting the inner wall surface of the in-block exhaust passage 22c on the side close to the cylinder liner 23 (the side close to the piston 24 in FIG. 2) is made of a material having high heat conductivity ( It is preferable that it is made of copper or the like. That is, the material constituting the inner wall surface (piston side inner wall surface) of the in-block exhaust passage 22c is configured to have higher thermal conductivity than the material constituting the opposite inner wall surface. Is preferred.

  According to such a configuration, the heat of the exhaust gas can be efficiently recovered by the piston-side inner wall surface of the in-block exhaust passage 22c. Therefore, the inner wall surface (see FIG. 2) of the cylinder 22a facing the piston 24 in the cylinder block 22 can be warmed up better by the heat of the exhaust gas.

  In this case, as shown in FIG. 6, a heat insulating member 223 constituting an inner wall surface other than the piston-side inner wall surface (including an inner wall surface opposite to the piston-side inner wall surface) is provided. Also good. The heat insulating member 223 can be made of a material having a lower thermal conductivity than the heat conducting member 222. Alternatively, the heat insulating member 223 can be omitted (see FIG. 7).

  Referring to FIG. 8, fins 222 a may be formed on the heat conducting member 222 constituting the piston-side inner wall surface.

  (5) The block side passage of the present invention is not limited to the one provided inside the cylinder block 22 such as the above-described in-block exhaust passage 22c. For example, the block side passage may be attached to the cylinder block 22 so as to contact the outer wall of the cylinder block 22.

  (6) The block side passage of the present invention is not limited to the one constituting the EGR passage 5. For example, the exhaust gas led out from the downstream exhaust pipe 44 and introduced into the cylinder block 22 (intra-block exhaust passage 22c) may be returned to the downstream exhaust pipe 44 again.

  (7) The turbocharger 63 can be omitted. Alternatively, other types of superchargers can be used instead of the turbocharger 63.

  (8) Other modifications not specifically mentioned are naturally included in the scope of the present invention as long as they do not change the essential part of the present invention. For example, in the description of each embodiment described above, the integrally formed components may be integrally formed without joints, or a plurality of separate parts may be joined by bonding, welding, screwing, or the like. Of course, it may be formed by.

  (9) In addition, in each element constituting the means for solving the problems of the present invention, the elements expressed in terms of operation and function are the specific structures disclosed in the above-described embodiments and modifications. In addition, any structure capable of realizing the action / function is included.

1 is a schematic diagram showing an overall configuration of an exhaust gas treatment system according to an embodiment of the present invention. FIG. 2 is a side sectional view of the engine shown in FIG. 1. It is the schematic which shows the structure of one modification of the exhaust-gas processing system shown by FIG. It is the schematic which shows the structure of the other modification of the exhaust-gas processing system shown by FIG. FIG. 3 is an enlarged side sectional view showing a specific example of an internal configuration of an in-block exhaust passage shown in FIG. 2. FIG. 3 is an enlarged side sectional view showing a specific example of an internal configuration of an in-block exhaust passage shown in FIG. 2. FIG. 3 is an enlarged side sectional view showing a specific example of an internal configuration of an in-block exhaust passage shown in FIG. 2. FIG. 3 is an enlarged side sectional view showing a specific example of an internal configuration of an in-block exhaust passage shown in FIG. 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Exhaust gas treatment system 2 ... Engine 21 ... Cylinder head 21a ... Intake port 21b ... Exhaust port 22 ... Cylinder block 22a ... Cylinder 22b ... Lower water jacket 22c ... In-block exhaust passage 221 ... Fin 222 ... Heat conduction member 222a ... Fin 223 ... Heat insulation member 23 ... Cylinder liner 24 ... Piston 3 ... Intake passage 31 ... Intake manifold 32 ... High pressure side intake pipe 33 ... Low pressure side intake pipe 4 ... Exhaust passage 41 ... Exhaust manifold 42 ... High pressure side exhaust pipe 43 ... Low pressure side exhaust Pipe 44 ... Downstream exhaust pipe 5 ... EGR passage 51 ... Exhaust outlet pipe 52 ... Outer block passage 53 ... Block introduction pipe 54 ... Block outlet pipe 55 ... Exhaust introduction pipe 56 ... High pressure loop pipe 57 ... Low pressure loop outlet pipe 58 ... Low pressure Loop introduction pipe 59 ... High-pressure side bypass pipe 63 ... Turbocha 63a ... Turbine part 63b ... Compressor part 64 ... Catalytic device 65 ... EGR cooler 66 ... EGR valve 67 ... EGR switching valve 68 ... High pressure EGR valve 68a ... High pressure EGR valve 68b ... Bypass switching valve 69b ... Exhaust introduction switching valve 69b ... Low pressure EGR switching valve CC ... Combustion chamber

Claims (17)

A cylinder head formed with an intake port and an exhaust port;
An intake passage connected to the intake port;
An exhaust passage connected to the exhaust port;
A purification treatment unit interposed in the exhaust passage and configured to purify exhaust gas discharged from the exhaust port;
An EGR passage provided so as to connect the exhaust passage and the intake passage;
A cylinder block joined to the cylinder head;
With
The engine exhaust gas processing device according to claim 1, wherein the EGR passage includes a passage on the exhaust gas which is a block side passage provided in the cylinder block. The exhaust gas treatment device for an engine according to claim 1,
In the EGR passage,
A block outer passage different from the block side passage is included,
An exhaust gas processing apparatus for an engine, wherein an EGR switching valve configured to be able to switch a use state of the outside-block passage and the block-side passage is interposed. The engine exhaust gas treatment device according to claim 1 or 2,
A turbocharger interposed in the exhaust passage between the cylinder head and the purification processing unit and interposed in the intake passage;
An upstream end of the block side passage in the exhaust gas flow direction is connected to a low pressure loop outlet pipe provided to branch from the exhaust passage at a position downstream of the purification processing portion in the direction. And
The downstream end of the block side passage in the direction is connected to a low-pressure loop introduction pipe provided to join the intake passage at a position upstream of the turbocharger in the intake air flow direction. An exhaust gas treatment device for an engine characterized by comprising: An exhaust gas treatment device for an engine according to claim 3,
An upstream end of the block side passage in the exhaust gas flow direction is connected to a high-pressure loop outlet pipe provided to branch from the exhaust passage at a position between the cylinder head and the turbocharger. And
The downstream end of the block side passage in the exhaust gas flow direction is connected to a high-pressure loop introduction pipe provided to join the intake passage at a position between the turbocharger and the cylinder head. An exhaust gas treatment device for an engine characterized by comprising: An exhaust gas treatment device for an engine according to claim 4,
Introducing the exhaust gas into the intake passage through the low pressure loop outlet pipe, the block side passage, and the low pressure loop introduction pipe, the high pressure loop outlet pipe, the block side passage, and the high pressure loop introduction pipe An exhaust gas processing device for an engine, characterized in that the exhaust gas can be switched between introduction into the intake passage via the engine The engine exhaust gas treatment device according to claim 1 or 2,
A turbocharger interposed in the exhaust passage between the cylinder head and the purification processing unit and interposed in the intake passage;
An upstream end of the block side passage in the exhaust gas flow direction is connected to a high-pressure loop outlet pipe provided to branch from the exhaust passage at a position between the cylinder head and the turbocharger. And
The downstream end of the block side passage in the exhaust gas flow direction is connected to a high-pressure loop introduction pipe provided to join the intake passage at a position between the turbocharger and the cylinder head. An exhaust gas treatment device for an engine characterized by comprising: An engine exhaust gas treatment device according to any one of claims 1 to 6,
The exhaust gas processing apparatus for an engine, wherein the block side passage is provided inside the cylinder block. An exhaust gas treatment device for an engine according to claim 7,
The exhaust gas processing device for an engine, wherein the block side passage is provided at a position corresponding to a lower portion of the cylinder. An exhaust gas treatment device for an engine according to any one of claims 1 to 8,
An exhaust gas processing apparatus for an engine, wherein fins are provided on an inner wall of the block side passage. An engine exhaust gas treatment device according to any one of claims 1 to 9,
The material constituting the inner wall surface on the side close to the piston of the block side passage is configured to have higher thermal conductivity than the material constituting the inner wall surface on the opposite side, Engine exhaust gas treatment device. A cylinder head formed with an intake port and an exhaust port;
An intake passage connected to the intake port;
An exhaust manifold connected to the exhaust port;
An exhaust pipe connected to the exhaust manifold;
A purification treatment unit interposed in the exhaust pipe and configured to purify the exhaust gas discharged from the exhaust port;
A cylinder block provided with a block side passage which is a passage of the exhaust gas and joined to the cylinder head;
With
The downstream end of the block side passage in the flow direction of the exhaust gas is connected to a position other than the position between the exhaust manifold and the purification processing section in the gas flow path. Engine exhaust gas treatment device. An engine exhaust gas treatment device according to claim 11,
An exhaust gas processing apparatus for an engine, wherein the end portion of the EGR passage as the block side passage is connected to the intake passage. The engine exhaust gas treatment device according to claim 11 or 12,
An exhaust gas processing apparatus for an engine, further comprising a switching valve configured to be able to switch whether or not the exhaust gas is introduced into the block side passage. An exhaust gas treatment apparatus for an engine according to any one of claims 11 to 13,
The exhaust gas processing apparatus for an engine, wherein the block side passage is provided inside the cylinder block. The exhaust gas treatment device for an engine according to claim 14,
The exhaust gas processing device for an engine, wherein the block side passage is provided at a position corresponding to a lower portion of the cylinder. An engine exhaust gas treatment device according to any one of claims 11 to 15,
An exhaust gas processing apparatus for an engine, wherein fins are provided on an inner wall of the block side passage. An engine exhaust gas treatment device according to any one of claims 11 to 16,
The material constituting the inner wall surface on the side close to the piston of the block side passage is configured to have higher thermal conductivity than the material constituting the inner wall surface on the opposite side, Engine exhaust gas treatment device.

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