JP6155891B2 - Condensate treatment mechanism - Google Patents

Description

  The present invention relates to treatment of condensed water generated in an intake system of an engine.

In order to improve the engine output, a technique for improving the volume efficiency in the combustion chamber by cooling the intake air compressed by the supercharger and supplying it to the combustion chamber has been put into practical use.
In order to reduce nitrogen oxides (hereinafter referred to as “NOx”) in exhaust gas, an EGR (Exhaust Gas Recirculation) system that recirculates part of the exhaust gas to the intake passage and reburns it with fresh air has been put into practical use. ing.

Conventionally, an EGR system that recirculates exhaust gas upstream of the exhaust treatment device downstream of the intercooler (so-called high pressure EGR) has been used, but recently, the exhaust gas downstream of the exhaust treatment device is supercharged. A device that recirculates upstream of the vessel (hereinafter referred to as “low pressure EGR”) has been developed.
Normally, exhaust gas contains water vapor generated by combustion, and therefore contains more water vapor than fresh air. For this reason, the intake air including the exhaust gas recirculated by the low pressure EGR is compressed by the supercharger and cooled by the intercooler, whereby the water vapor in the intake air is condensed and water (hereinafter referred to as “condensed water”) is generated. May be.

If this condensate flows into the combustion chamber, for example, combustion may be unstable during low-temperature combustion or idling of the engine, and the required torque may be output during high-load operation of the engine. You may not be able to. Thus, a malfunction may occur due to the inflow of condensed water into the combustion chamber.
Therefore, a technology for treating condensed water generated by an intercooler in an intake / exhaust system equipped with a low pressure EGR has been developed. Such techniques are disclosed in, for example, Patent Documents 1 and 2.

  In Patent Document 1, a condensed water tank for storing condensed water is provided integrally with an intercooler, and the stored condensed water is purified by condensed water purification means having a filter or the like. It is shown that it is sprayed on an air-cooled type heat exchanger such as an intercooler or an EGR cooler. Thereby, it is supposed that effective use of condensed water can be aimed at.

  Patent Document 2 discloses a condensate that is provided in an intercooler and accumulates condensed water, a condensate drain passage that connects the reservoir and a downstream side of a connection portion on the exhaust side of the low-pressure EGR, and the condensate drain. The thing provided with the on-off valve interposed by the channel | path is shown. By opening and closing this on-off valve according to the operating state of the engine, it is possible to prevent the backflow and discharge condensed water, and to secure intake pressure (avoid so-called boost loss) to improve the performance of the internal combustion engine. Deterioration can be avoided.

JP 2012-189022 A Japanese Patent No. 3666583

  However, in the techniques of Patent Document 1 and Patent Document 2, since condensed water is stored in the intercooler, this condensed water may be wound up into the intake air and flow into the combustion chamber. Therefore, a problem may occur depending on the operating state of the engine.

One of the objects of the present invention has been conceived in view of the above-described problems, and prevents the condensate from being rolled up by intake air so that the condensed water can be appropriately treated. Is to provide.
Note that the present invention is not limited to this purpose, and other effects of the present invention can also be achieved by the functions and effects derived from the respective configurations shown in the embodiments for carrying out the invention which will be described later. Can be positioned as

  (1) In order to achieve the above object, the condensate treatment mechanism of the present invention is interposed downstream of a supercharger that supercharges intake air in an intake passage of an engine, and is supercharged by the supercharger. An intercooler that cools the intake air, an EGR passage that connects the exhaust passage of the engine and the upstream side of the supercharger of the intake passage, and one end of the intercooler or the intercooler of the intake passage The other end is connected to the exhaust passage, the condensed water passage through which the condensed water generated by the intercooler flows, and the condensed water passage is interposed to store the condensed water. And a back pressure switching valve interposed on the one end side of the condensate water passage from the storage portion of the condensate water passage, one end is connected to the exhaust passage, and the other end is the Back connected to back pressure switching valve And the back pressure switching valve communicates the one end portion of the condensed water passage and the storage portion, and communicates the exhaust passage and the storage portion via the back pressure passage. Switching between a state in which the exhaust passage is shut off, and a state in which the communication between the one end portion of the condensed water passage and the storage portion is cut off, and the exhaust passage and the storage portion are connected via the back pressure passage. It is characterized by.

(2) An exhaust treatment device that is disposed in the exhaust passage and purifies exhaust gas, and is disposed closer to the other end portion of the condensed water passage than the storage portion of the condensed water passage. A filter to be purified, a regeneration switching valve interposed between the storage portion of the condensed water passage and the filter, one end connected to the exhaust passage, and the other end to the regeneration switching valve It is preferable to provide a connected regeneration passage. In this case, it is preferable that the one end portion of the back pressure passage is connected to a downstream side of the exhaust treatment device of the exhaust passage. Moreover, it is preferable that the said filter is a regeneration filter which can reproduce | regenerate purification | cleaning capability by heating. Further, the regeneration switching valve communicates the storage portion and the exhaust passage via the filter, and blocks communication between the one end portion of the regeneration passage and the exhaust passage via the filter. And a state where the storage portion and the exhaust passage via the filter are blocked, and the one end portion of the regeneration passage and the exhaust passage via the filter are communicated. It is preferable. In addition, the exhaust treatment device includes a primary exhaust treatment device with a temperature raising function and a secondary exhaust treatment device that is disposed downstream of the primary exhaust treatment device and purifies the exhaust, It is preferable that the one end portion is connected to the downstream side of the primary exhaust treatment device in the exhaust passage and the upstream side of the secondary exhaust treatment device.

( 3 ) It is preferable that the one end portion of the back pressure passage is connected to a downstream side of the secondary exhaust treatment device of the exhaust passage.
( 4 ) It is preferable to include a valve that is interposed between the storage section in the condensed water passage and the regeneration switching valve and that can adjust the opening degree.
( 5 ) It is preferable that the one end portion of the condensed water passage is a slit or a pore formed in an intake pipe that forms the intake passage.
( 6 ) It is preferable that the one end portion of the condensed water passage is connected to a portion having the lowest vertical height in the intake passage.

  According to the condensed water treatment mechanism of the present invention, the condensed water generated by the intercooler flows through the condensed water passage and is stored in the storage portion. Winding up can be prevented.

  The back pressure switching valve communicates between one end of the condensate water passage and the storage portion and blocks communication between the exhaust passage and the storage portion via the back pressure passage (herein referred to as “storage state”), The state where the communication between the one end portion of the water passage and the storage portion is blocked and the exhaust passage and the storage portion are connected via the back pressure passage is switched (herein referred to as “discharge state”). For this reason, when switched to the storage state by the back pressure switching valve, the communication between the exhaust passage and the storage unit is blocked, and condensed water can be stored in the storage unit. In addition, when the back pressure switching valve is switched to the discharge state, the communication between the exhaust passage and the storage portion is communicated while the communication between the one end portion of the condensed water passage connected to the intake passage and the storage portion is blocked. Condensed water stored in the storage portion can be discharged to the exhaust passage while ensuring the intake pressure (avoiding so-called boost loss) and ensuring the performance of the engine.

  In this way, because it has a reservoir for storing condensed water and a back pressure switching valve interposed upstream from this, and a back pressure passage connected to the back pressure switching valve and the exhaust passage, It is possible to prevent the condensed water from being rolled up and appropriately treat the condensed water.

It is a schematic diagram which shows the condensed water processing mechanism which concerns on one Embodiment of this invention, and the intake / exhaust system of the engine to which this is applied. It is an AA arrow line view of FIG.

Embodiments of the present invention will be described below with reference to the drawings. The condensed water treatment mechanism of the present invention is applied to an intake / exhaust system of an engine. For this reason, the configuration of the engine and its intake / exhaust system, which are the preconditions for the condensed water treatment mechanism of the present invention, will be described, the configuration of the condensed water treatment mechanism will be described next, and then the condensed water treatment mechanism will be controlled. The configuration of the control device will be described.
The upstream and downstream in this embodiment are based on the direction in which intake air, exhaust gas or condensed water flows.

[One Embodiment]
[1. Constitution〕
[1-1. Engine and its intake and exhaust system)
First, the configuration of the engine and its intake system and exhaust system will be described with reference to FIG.
[1-1-1. engine〕
The engine 1 is a diesel engine and includes a cylinder head 2, a cylinder block 3, and a crankcase 4. The engine 1 is configured as a multi-cylinder engine having a plurality of cylinders (not shown).

  In the cylinder head 2, an intake port 2a and an exhaust port 2b are provided in communication with the combustion chamber 5, and an injector 2c for injecting fuel corresponding to each cylinder is provided. Although not shown in detail, each injector 2c is connected to a common rail via a supply pump (high pressure pump) for supplying fuel from the fuel tank, and the high pressure fuel supplied by the supply pump is supplied from the common rail to each injector 2c. And injected into the corresponding cylinder, and the injected fuel and intake air are mixed and burned.

  A cylindrical space (hereinafter referred to as “cylinder”) is formed in the cylinder block 3, and a piston 3 a is provided in the cylinder so as to be capable of reciprocating. The combustion chamber 5 is formed so as to be surrounded by the cylinder block 3, the piston 3 a and the cylinder head 2.

The crankcase 4 stores engine oil 6 therein and accommodates a crankshaft 4a. The crankshaft 4a has an input side connected via a piston 3a and a connecting rod 3b, and an output side connected to an output shaft (not shown) of the engine 1. Therefore, the rotational speed of the crankshaft 4a is the same as or corresponds to the rotational speed of the engine 1.
Further, the engine 1 is provided with a crank angle sensor 90 that detects the rotation angle of the crankshaft 4a and detects the rotation speed of the engine 1 (hereinafter referred to as “engine rotation speed”) from the rotation angle.

[1-1-2. (Intake system)
Next, the configuration of the intake system provided on the upstream side of the engine 1 will be described.
The intake system includes an intake pipe 10 and each device interposed or attached thereto, and an intake manifold (hereinafter abbreviated as “intake manifold”) interposed between the intake pipe 10 and the intake port 2a of the engine 1. 19).
The intake pipe 10 and each device intervening or attached to the intake pipe 10 and the intake manifold 19 form an intake passage 10A (in FIG. 1, only one place is given a reference).

Hereinafter, the configuration of the intake system will be described in order from the upstream.
An air cleaner 20, a first throttle valve 21, a compressor 50 a of a turbocharger (supercharger) 50, an intercooler 22, and a second throttle valve 23 are arranged in the intake pipe 10 in order from the upstream.

  The air cleaner 20 is a filter that removes foreign matter in the fresh air that is inhaled. The air cleaner 20 is provided with a humidity sensor 91 that detects the humidity (water vapor amount) in the fresh air. Further, an air flow sensor 92 that detects the flow speed of fresh air that has passed through the air cleaner 20 (flow rate per unit time, hereinafter referred to as “fresh air amount”) is provided immediately downstream of the air cleaner 20.

  The first throttle valve 21 adjusts the amount of fresh air according to the throttle opening. A low pressure EGR system 51 described later is connected downstream of the first throttle valve 21 and upstream of the compressor 50 a of the turbocharger 50, and the low pressure EGR system is adjusted by adjusting the first throttle valve 21. The amount of exhaust gas recirculated by 51 is also indirectly adjusted.

The turbocharger 50 compresses intake air. Specifically, the intake air flowing through the turbocharger 50 is compressed by rotating a compressor 50a provided coaxially with the turbine 50b rotated by exhaust gas.
The intercooler 22 is an intake air cooling device. In the intercooler 22, the intake air temperature that has been compressed and increased by the turbocharger 50 is reduced, and the reduction in the air density of the intake air is recovered.

  The intake pipe 10 downstream of the intercooler 22 and upstream of the second throttle valve 23 has a portion (hereinafter referred to as “lowest part”) 10 a having the lowest vertical height in the intake pipe 10. . The lowest portion 10a is lower than the vertical height of the intake manifold 19. That is, the lowest part 10a forms a part having the lowest vertical height in the intake passage 10A. A condensate treatment mechanism 60 described later is connected to the lowest part 10a.

The second throttle valve 23 adjusts the intake air amount according to the throttle opening. A high-pressure EGR system 52 is connected downstream of the second throttle valve 23 and upstream of the intake manifold 19, and a condensed water treatment mechanism 60 described later is provided upstream of the second throttle valve 23. It is connected. By adjusting the second throttle valve 23, the amount of exhaust gas recirculated by the high pressure EGR system 50 is indirectly adjusted.
The intake manifold 19 is provided with a linear air-fuel ratio sensor (so-called LAFS) 93 that continuously detects the air-fuel ratio.

[1-1-3. (Exhaust system)
Next, the configuration of the exhaust system provided on the downstream side of the engine 1 will be described.
The exhaust system is provided with an exhaust manifold (hereinafter abbreviated as “exhaust manifold”) 39, an exhaust pipe 30 connected to the downstream side, and each device interposed or attached thereto.
The exhaust manifold 39, the exhaust pipe 30, and each device interposed or attached thereto form an exhaust passage 30A (in FIG. 1, only one place is indicated).

Hereinafter, the configuration of the exhaust system will be described in order from the upstream.
A high pressure EGR system 52 described later is connected to the exhaust manifold 39.
In the exhaust pipe 30, the turbine 50b of the turbocharger 50, the primary exhaust treatment device 40, and the secondary exhaust treatment device 41 are arranged in this order from the upstream.

  The primary exhaust treatment device 40 is for collecting particulate matter (hereinafter referred to as “PM”) in the exhaust. The primary exhaust treatment device 40 includes an upstream DOC (Diesel Oxidation Catalyst) 40a and a downstream DPF (Diesel Particulate Filter) 40b.

  The DOC 40a is a catalyst having an ability to oxidize components in exhaust gas, and is a catalyst in which a catalyst is supported on a honeycomb-shaped carrier made of metal or ceramics. Examples of components in the exhaust gas oxidized by the DOC 40a include NO (nitrogen monoxide), HC (hydrocarbon) and CO (carbon monoxide) in unburned fuel.

The DPF 40b is a porous filter that collects PM contained in the exhaust gas. A large number of passages that connect the upstream side and the downstream side are arranged in parallel through the wall, and the upstream side opening and the downstream side of the passage The side openings are alternately closed (sealed). A large number of pores having a size corresponding to the size of PM are formed in the wall of the DPF 40b. For this reason, when the exhaust gas containing PM circulates through the DPF 40b, PM is collected on the wall body or the wall body surface.
Further, the primary exhaust treatment device 40 is provided with a differential pressure sensor 94 that detects a differential pressure between the upstream side and the downstream side of the DPF 40b.

In the primary exhaust treatment device 40, the DPF 40b on the downstream side of the DOC 40a is heated by oxidizing (combusting) the reducing components in the exhaust with the DOC 40a to generate oxidation heat (combustion heat), and is collected by the DPF 40b. PM is incinerated (DPF regeneration). Thus, the primary exhaust treatment device 40 has an exhaust temperature raising function by oxidation heat.
Further, the sulfur component occluded in the secondary exhaust treatment device 41 on the downstream side of the primary exhaust treatment device 40 is released (so-called S purge) by the heat of oxidation by the DOC 40a.
It should be noted that main parts of a condensate treatment mechanism 60 and a low pressure EGR 51, which will be described later, are connected to the downstream side of the primary exhaust treatment device 40 and the upstream side of the secondary exhaust treatment device 41 in order from the upstream side. .

The secondary exhaust treatment device 41 is for purifying NOx contained in the exhaust. More specifically, the secondary exhaust treatment device 41 uses bases such as barium and potassium as storage materials and stores NOx as nitrates. In this way, the secondary exhaust treatment device 41 purifies exhaust without generating heat.
A condensate treatment mechanism 60 described later is connected to the exhaust passage 30A on the downstream side of the secondary exhaust treatment device 41 at two locations.

[1-1-4. EGR]
In this intake / exhaust system, a low pressure EGR system 51 and a high pressure EGR system 52 are provided across the intake system and the exhaust system. These EGR systems 51 and 52 are for reducing NOx by recirculating exhaust gas to intake air.

  The low pressure EGR system 51 is configured so that the exhaust flowing downstream from the primary exhaust treatment device 40 and upstream from the secondary exhaust treatment device 41 is downstream from the first throttle valve 21 and from the turbine 50a of the turbocharger 50. The air is recirculated to the upstream intake passage 10A. The low-pressure EGR system 51 includes a low-pressure EGR pipe 51c that connects one end 51a that is an end on the exhaust side and the other end 51b that is an end on the intake side, and a low-pressure that is interposed in the low-pressure EGR pipe 51c. It has an EGR cooler 51d and a low pressure EGR valve 51e.

Inside the low-pressure EGR pipe 51c, a low-pressure EGR passage 51A through which the recirculated exhaust gas flows is formed. One end 51a of the low pressure EGR pipe 51c is connected to the downstream side of the primary exhaust treatment device 40 and the upstream side of the secondary exhaust treatment device 41. On the other hand, the other end 51 b of the low pressure EGR pipe 51 c is connected to the downstream side of the first throttle valve 21 and to the upstream side of the compressor 50 a of the turbocharger 50.
The low-pressure EGR cooler 51d is a cooling device that lowers the temperature of the recirculated exhaust gas. A low pressure EGR valve 51e is provided on the other end 51b side (intake side) of the low pressure EGR cooler 51d.
The low pressure EGR valve 51e adjusts the recirculation amount of the exhaust gas by the low pressure EGR system 51, and is configured as a valve whose opening degree can be adjusted.

  The high-pressure EGR system 52 recirculates the exhaust gas flowing through the exhaust manifold 39 to a portion downstream of the second throttle valve 23 in the intake passage 10A. The high pressure EGR system 52 includes a high pressure EGR pipe 52c that connects one end 52a that is an end on the exhaust side and the other end 52b that is an end on the intake side, and a high pressure that is interposed in the high pressure EGR pipe 52c. It has an EGR cooler 52d and a high-pressure EGR valve 52e.

Inside the high-pressure EGR pipe 52c, a high-pressure EGR passage 52A through which the recirculated exhaust gas flows is formed. One end portion 52 a of the high pressure EGR pipe 52 c is connected to the exhaust manifold 39. On the other hand, the other end 52 b of the high pressure EGR pipe 52 c is connected to the downstream side of the second throttle valve 23 and to the upstream side of the intake manifold 19.
The high pressure EGR cooler 52d is a cooling device configured in the same manner as the low pressure EGR cooler 51d, and the high pressure EGR valve 52e is a valve with an adjustable opening configured in the same manner as the low pressure EGR valve 51e.

[1-2. Condensate treatment mechanism)
Next, the configuration of the condensed water treatment mechanism 60 applied to the intake / exhaust system of the engine 1 will be described.
The condensed water treatment mechanism 60 is a mechanism for treating the condensed water generated when the intake air compressed by the turbocharger 50 is cooled by the intercooler 22. Specifically, the condensed water to be stored in the lowest portion 10a is guided and stored outside the intake passage 10A, and the condensed water is discharged to the exhaust passage 30A.

  For this purpose, the condensed water treatment mechanism 60 includes a condensed water pipe 61 that internally forms a condensed water passage 60A through which condensed water flows, a tank (storage part) 62 that stores condensed water, a back pressure switching valve 63, It has an on-off valve 64, a back pressure pipe 65 that forms a back pressure passage 65A inside, a regeneration pipe 66 that forms a regeneration passage 66A inside, a regeneration switching valve 67, and a filter 68. The condensed water pipe 61 is provided with a back pressure switching valve 63, a tank 62, an on-off valve 64, a regeneration switching valve 67, and a filter 68 in the order in which the condensed water flows. Further, a back pressure pipe 65 is connected to the back pressure switching valve 63, and a regeneration pipe 66 is connected to the regeneration switching valve 67.

In the following description, the condensed water passage 60A is divided into four parts. Specifically, the first condensed water passage 61 </ b> A to the back pressure switching valve 63, the second condensed water passage 61 </ b> B from the back pressure switching valve 63 to the tank 62, and the regeneration from the tank 62 in the order in which the condensed water flows. A description will be given by dividing into four parts, a third condensed water passage 61C up to the switching valve 67 and a fourth condensed water passage 61D downstream of the regeneration switching valve 67.
Hereinafter, each structure is demonstrated in order of the condensed water pipe | tube 61, the tank 62, the back pressure switching valve 63, the back pressure piping 65, the on-off valve 64, the regeneration switching valve 67, the regeneration piping 66, and the filter 68.

  The condensed water pipe 61 has an end on the side into which condensed water flows (corresponding to one end 61a of the condensed water passage 60A) connected to the lowest part 10a of the intake pipe 10, and an end on the side from which condensed water flows out (condensed) The other end 61b of the water passage 60A) is connected to the exhaust pipe 30 that forms the exhaust passage 30A. The other end 61 b of the condensed water pipe 61 is connected downstream of any of the exhaust treatment devices 40 and 41.

As shown in FIG. 2, a plurality of slits 11 (symbols are attached to only one place) are provided in the lowest part 10a of the intake pipe 10 to which one end 61a (all indicated by a broken line) of the condensed water passage 60A is connected. Is provided.
The slit 11 is provided with a size or an arrangement that does not hinder the flow of intake air along the intake pipe 10. Here, a plurality of slits 11 are arranged in a staggered manner, and the slits 11 are oriented so that the longitudinal direction of the slits 11 is along the flow direction of intake air. According to the staggered arrangement of the plurality of slits 11, it is easy to ensure a degree of freedom in setting the size of the slits 11, and it is difficult to prevent the intake air flow by making the longitudinal direction of each slit 11 follow the intake air flow direction. be able to. However, the orientation and arrangement of the slits 11 are arbitrary, and other orientations and arrangements can be adopted.

  As shown in FIG. 1, the tank 62 has a condensed water inflow port 62a formed in the upper portion thereof, and a condensed water outflow port 62b formed in the lower portion thereof. In other words, the inflow port 62a is provided at a portion higher than the outflow port 62b. That is, in the tank 62, the outflow port 62b is easily immersed by the stored condensed water, and the inflow port 62a is not easily immersed by the stored condensed water.

The back pressure switching valve 63 is interposed between the end of the condensed water pipe 61 on the side into which the condensed water flows (one end 61a of the condensed water passage 60A) and the tank 62, and connects the two systems on the inflow side. There are provided a first inflow connection portion 63a and a second inflow connection portion 63b as parts, and an outflow connection portion 63c as a connection portion of one system on the outflow side. In the back pressure switching valve 63, (i) one of the inflow connection portions 63a and 63b and the outflow connection portion 63c communicate with each other, and the other of the inflow connection portions 63a and 63b and the outflow connection portion 63c are disconnected. And (ii) a state in which the other of the inflow connection portions 63a and 63b and the outflow connection portion 63c are communicated with each other, and a communication between one of the inflow connection portions 63a and 63b and the outflow connection portion 63c is blocked, Is to switch.
Here, the condensed water pipe 61 is connected to each of the first inflow connection portion 63a and the outflow connection portion 63c, and the back pressure pipe 65 is connected to the second inflow connection portion 63b.

  Therefore, the back pressure switching valve 63 (i) the first condensed water passage 61A and the second condensed water passage 61B communicate with each other, and the communication between the back pressure passage 65A and the second condensed water passage 61B is blocked. (Ii) switching between the first condensed water passage 61A and the second condensed water passage 61B is blocked, and the back pressure passage 65A and the second condensed water passage 61B are communicated. It is like that.

  In other words, the back pressure switching valve 63 communicates (i) the one end portion 61a of the condensed water passage 61A and the tank 62, and blocks communication between the exhaust passage 30A and the tank 62 via the back pressure passage 65A. A state (hereinafter referred to as “reserved state”), and (ii) the communication between the one end portion 61a of the condensed water passage 61A and the tank 62 and the exhaust passage 30A and the tank 62 via the back pressure passage 65A. The communication state (hereinafter referred to as “discharge state”) can be switched.

  The back pressure pipe 65 is connected to the exhaust pipe 30 on the downstream side of the exhaust treatment devices 40 and 41 at the end on the side into which the exhaust flows (corresponding to the one end 65a of the back pressure passage 65A). The end portion (corresponding to the other end portion 65b of the back pressure passage 65A) is connected to the back pressure switching valve 63. One end portion 65 a of the back pressure pipe 65 is connected to the exhaust pipe 30 on the downstream side of the condensed water pipe 61.

  The on-off valve 64 is interposed between the tank 62 and the regeneration switching valve 67 (the third condensed water passage 61C). The opening / closing valve 64 is a valve whose opening degree can be adjusted, and according to the opening degree of the opening / closing valve 64, the degree of condensate flow (discharge) in the third condensed water passage 61 </ b> C in which the opening / closing valve 64 is disposed. Degree) is adjusted.

The regeneration switching valve 67 is interposed between the tank 62 and the filter 68, and includes a first inflow connection portion 67a and a second inflow connection portion 67b as two inflow side connection portions, and an outflow side connection portion. The outflow connection part 67c as a one-system connection part is provided. Similar to the back pressure switching valve 63 described above, the regeneration switching valve 67 is configured such that when one of the inflow connection portions 67a and 67b communicates with the outflow connection portion 67c, the other of the inflow connection portions 67a and 67b. And the outflow connection portion 67c are blocked.
Here, the condensed water pipe 61 is connected to each of the first inflow connection portion 67a and the outflow connection portion 67c, and the regeneration pipe 66 is connected to the second inflow connection portion 67b.

  For this reason, the regeneration switching valve 67 is configured such that (I) the third condensed water passage 61C and the fourth condensed water passage 61D communicate with each other, and the communication between the regeneration passage 66A and the fourth condensed water passage 61D is blocked. And (II) the communication between the third condensed water passage 61C and the fourth condensed water passage 61D is cut off, and the state where the regeneration passage 66A and the fourth condensed water passage 61D are communicated is switched. It is like that.

  In other words, the regeneration switching valve 67 communicates (I) the tank 62 and the exhaust passage 30A via the filter 68 and blocks communication between the regeneration passage 66A and the exhaust passage 30A via the filter 68. (II) The communication between the tank 62 and the exhaust passage 30A through the filter 68 is blocked, and the exhaust passage 30A through the regeneration passage 66A and the filter 68 is cut off. And a state (hereinafter referred to as “playback state”) communicating with each other.

The regeneration pipe 66 has an end on the side into which the exhaust flows (corresponding to one end 66a of the regeneration passage 66A) on the downstream side of the primary exhaust treatment device 40 and on the upstream side of the secondary exhaust treatment device 41. The exhaust pipe 30 is connected to the above-described regeneration switching valve 67. The end portion on the side from which the exhaust gas flows out (corresponding to the other end portion 66b of the regeneration passage 66A) is connected to the regeneration switching valve 67. One end portion 65 a of the regeneration pipe 66 is preferably connected immediately downstream of the primary exhaust treatment device 40.
The filter 68 is a regeneration filter that can regenerate the purification capability by heating. The filter 68 may be any filter that adsorbs or removes foreign substances that may be contained in the condensed water. For example, an activated carbon filter can be used.

[1-3. Control device〕
Next, the configuration of the control device 100 that controls the condensed water treatment mechanism 60 will be described. The control device 100 is an electronic control device configured as an LSI device or an embedded electronic device in which a microprocessor, ROM, RAM, and the like are integrated.

The control device 100 controls a wide range of intake and exhaust systems, sensors 90 to 94 for detecting various information used for control are connected to the input side, and valves 21 and 23 to be controlled are connected to the output side. , 51e, 52e, 63, 64, 67 are connected. This control apparatus 100 implements each control by adjusting each opening degree of the valves 21, 23, 51 e, 52 e, 63, 64, 67 based on the detection information from the sensors 90 to 94.
In the present embodiment, the control performed by the control device 100 will be described focusing on the control of the EGR systems 51 and 52 and the control of the condensed water treatment mechanism 60.

[1-3-1. Control of EGR system]
The low-pressure EGR system 51 is controlled mainly by adjusting the opening of the low-pressure EGR valve 51e, and is controlled by adjusting the opening of the first throttle valve 21 as a secondary. The recirculation amount of the exhaust gas is controlled by adjusting the opening degree of these valves 51e and 21, and the low pressure EGR system 51 is controlled.

Similarly, the high-pressure EGR system 52 is controlled mainly by adjusting the opening degree of the high-pressure EGR valve 52e, and secondarily by adjusting the opening degree of the second throttle valve 23. The recirculation amount of the exhaust gas is controlled by adjusting the opening degree of these valves 52e and 23, and the high pressure EGR system 52 is controlled.
The control device 100 controls the opening degree of the valves 21, 23, 51 e, 52 e applied to the EGR systems 51, 52 based on the detection information from the sensors 90 to 94, and controls the exhaust gas recirculation amount.

[1-3-2. Control of condensed water treatment mechanism)
The condensed water treatment mechanism 60 is controlled by adjusting the opening degree of the on-off valve 64 and switching the switching valves 63 and 67. Hereinafter, regarding the control of the condensed water treatment mechanism 60, storage control for storing condensed water, discharge control for discharging condensed water, and regeneration control for regenerating the filter 68 will be described.

[1-3-2-1. Storage control)
In the storage control, condensed water is guided from the intake passage 10 </ b> A to the outside of the system and stored in the tank 62. In this storage control, the back pressure switching valve 63 is set to the storage state (i), and the regeneration switching valve 67 is set to the regeneration state (II). In the storage control, the opening / closing valve 64 is not controlled, and the opening degree is arbitrary.

[1-3-2-2. Emission control)
In the discharge control, the condensed water stored in the tank 62 is discharged to the intake passage 10 </ b> A formed by the intake manifold 19. In this discharge control, the back pressure switching valve 63 is set to the discharging state (ii), the regeneration switching valve 67 is set to the condensed water purifying state (I), and the on-off valve 64 is at least opened. In addition, the opening degree of the on-off valve 64 is adjusted according to the desired degree of drainage of condensed water.

[1-3-2-2-3. Playback control)
In the regeneration control, the purification ability is regenerated by heating the filter 68. In this regeneration control, the state of each of the valves 63, 64, 67 is the same as in the storage control, the back pressure switching valve 63 is set to the storage state (i), and the regeneration switching valve 67 is the regeneration (II). Put into state. For this reason, regeneration control and storage control are substantially the same and are performed simultaneously.

[1-3-2-4. Control conditions)
The control device 100 performs storage control, discharge control, and regeneration control according to various conditions. The control device 100 estimates and calculates the amount of condensed water generated based on detection information from the humidity sensor 91 and the airflow sensor 92. Further, the control device 100 determines whether or not the tank 62 is full of condensed water based on the estimated amount of condensed water generated and the capacity of the tank 62 stored in advance.

As long as the tank 62 is not filled with condensed water, the control device 100 may perform any of the storage control, the discharge control, and the regeneration control. The conditions for performing each control are exemplified below. When it is estimated that the tank 62 is full of condensed water, the discharge control is performed.
For example, the control device 100 performs storage control if the estimated amount of condensed water produced is less than a predetermined amount, and performs discharge control if the estimated amount of condensed water produced is greater than or equal to a predetermined amount. carry out. As the predetermined amount here, an amount such as half or 1/3 of the capacity of the tank 62 can be used.

  In addition, the control device 100 performs regeneration control when purifying exhaust gas due to temperature rise in the primary exhaust gas processing device 40 such as during DPF regeneration or S purge. At this time, since the exhaust gas whose temperature has been raised flows downstream of the primary exhaust treatment device 40 with a silencing function, the exhaust gas whose temperature has been increased is introduced into the filter 68. Instead of or in addition to this, the control device 100 may perform the regeneration control when the regeneration control is not performed for longer than a predetermined period.

[2. Action and effect)
Since the condensed water treatment mechanism 60 according to one embodiment of the present invention is configured as described above, the following operations and effects can be obtained.
The fresh air intake is throttled according to the throttle opening of the first throttle valve 21 through the air cleaner 20. At the other end 51 b of the downstream low pressure EGR system 51, the intake air in which the exhaust gas recirculated according to the opening degree of the low pressure EGR valve 51 e and the fresh air merge is compressed by the compressor 50 a of the turbocharger 50.

Normally, exhaust gas contains water vapor generated by combustion, and therefore contains more water vapor than fresh air. For this reason, when the intake air including the exhaust is compressed by the turbocharger 50 and cooled by the intercooler 22, the water vapor in the intake air may be condensed to generate condensed water.
The condensed water tends to accumulate in the lowest portion 10a of the intake pipe 10, but is led out of the intake system from one end portion 61a of the condensed water treatment mechanism 60 connected to the lowest portion 10a.

  In this case, if the storage control is performed, the condensed water is stored in the tank 62 from the lowest portion 10a of the intake pipe 10 through the first condensed water passage 61A and the second condensed water passage 61B. At this time, since the communication between the tank 62 and the exhaust passage 30A is blocked by the back pressure switching valve 63 in the storage state and the regeneration switching valve 67 in the regeneration state, the condensed water stored in the tank 62 is discharged from the exhaust passage. It is not discharged to 30A. In addition, when the storage control is performed, regeneration control is performed at the same time. When the regeneration switching valve 67 is set to the regeneration state, the inflow of condensed water to the filter 68 is blocked, and the exhaust gas flows through the filter 68. To do. The exhaust temperature is usually higher than the temperature of the condensed water, and the filter 68 is heated to regenerate its purification capacity.

When the discharge control is performed, the exhaust pressure in the exhaust passage 30 </ b> A via the back pressure passage 65 </ b> A becomes the back pressure for pushing out the condensed water stored in the tank 62. At this time, since the third condensed water passage 61C and the fourth condensed water passage 61D are communicated with each other by the open / close valve 64 and the regeneration switching valve 67 in the condensed water purification state, the condensed water stored in the tank 62 is reduced. Then, it is pushed out by the back pressure, purified by the filter 68 and discharged to the exhaust passage 30A.
Therefore, according to the condensed water treatment mechanism 60 of the present embodiment, condensed water does not accumulate in the intake passage 10A, and it is possible to prevent the condensed water from being rolled up.

  When the back pressure switching valve 63 is switched to the storage state, the communication between the exhaust passage 30 </ b> A and the tank 62 is blocked, and the condensed water can be stored in the tank 62. Further, when the back pressure switching valve 63 is switched to the discharge state, the communication between the one end portion 61a of the condensed water passage 60A connected to the intake passage 10A and the tank 62 is blocked, and the exhaust passage 30A and the tank 62 are disconnected. Since the communication is established, the condensed water stored in the tank 62 can be discharged to the exhaust passage 30A while ensuring the intake pressure (avoiding so-called boost loss) and ensuring the performance of the engine 1. At this time, since the condensed water is not discharged into the intake passage 10A, it is possible to avoid problems due to the inflow of the condensed water into the combustion chamber 5.

  As described above, the tank 62 for storing condensed water, the back pressure switching valve 63 interposed upstream from the tank 62, and the back pressure switching valve 63 and the back pressure passage 65A connected to the exhaust passage 30A are provided. Therefore, it is possible to prevent the condensed water from being rolled up and to appropriately treat the condensed water.

One end portion 65a of the back pressure passage 65A, that is, the exhaust inflow port is connected to the downstream side of the exhaust treatment devices 40 and 41 of the exhaust passage 30A, so that the condensed water is discharged using the purified exhaust gas. be able to. For this reason, exhaust gas performance can be ensured.
Since the filter 68 is provided on the downstream side of the tank 62 in the condensed water passage 60A, the condensed water can be purified and discharged.

Specifically, when regeneration control is performed and the regeneration switching valve 67 switches to the regeneration state, the purification of the condensed water by the filter 68 is stopped, and the exhaust gas heated by the primary exhaust treatment device 40 to the filter 68 is stopped. Can be distributed. Thereby, the purification capability of the filter 68 can be regenerated.
When the discharge control is performed and the regeneration switching valve 67 is switched to the condensed water purification state, the tank 62 and the exhaust passage 30A through the filter 68 are communicated, and the condensed water is purified by the filter 68 and exhausted. It can be discharged into the passage 30A.

  Since one end portion 66a of the regeneration passage 66A is connected to the downstream side of the primary exhaust treatment device 40 and the upstream side of the secondary exhaust treatment device 41, the temperature of the heated exhaust gas is reduced. The exhaust gas can be introduced into the filter 68 while suppressing the above. Thereby, the filter 68 can be efficiently regenerated. In particular, if the one end 66a of the regeneration passage 66A is connected directly downstream of the primary exhaust treatment device 40, the filter 68 can be regenerated more efficiently.

One end portion 65a of the back pressure passage 65A is connected further downstream than the secondary exhaust treatment device 41 interposed downstream from the primary exhaust treatment device 40, and is thus introduced into the back pressure passage 65A. Since the exhaust gas is purified by the primary exhaust treatment device 40 and further purified by the secondary exhaust treatment device 41, the burden of the purification treatment by the filter 68 can be reduced.
Since the opening / closing valve 64 capable of adjusting the opening degree is interposed between the tank 62 and the regeneration switching valve 67 in the condensed water passage 60A, the degree of discharge of condensed water can be adjusted.

Since one end portion 61a of the condensed water passage 60A is connected to the lowest portion 10a that forms the portion having the lowest vertical height of the intake passage 10A, the condensed water can be efficiently guided outside the intake system.
One end portion 61a of the condensed water passage 60A is a slit 11 formed in the lowest portion 10a of the intake pipe 10 that forms the intake passage 10A. Therefore, the condensed water is not disturbed and the condensed water is treated by the condensed water treatment mechanism 60. Can be introduced.

  As described above, since the flow of the condensed water in the intake passage 10A downstream of the one end portion 61a of the condensed water treatment mechanism 60 is avoided, the linear air-fuel ratio sensor 93 provided downstream of the one end portion 61a is covered. Water can be prevented. In other words, it is possible to prevent the various devices provided in the intake passage 10A on the downstream side of the one end 61a from being wetted, and to ensure the durability and reliability of the various devices. Can do.

[3. Others]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.
In the above-described embodiment, the lowest part 10a has the lowest vertical height in the intake pipe 10, but the lowest part 10a is at least the lowest in the intake passage 10A on the downstream side of the intercooler 19. It only has to be a part. Also in this case, the condensation that is to accumulate in the lowest part 10 a is appropriately processed by the condensed water treatment mechanism 60.

Moreover, although the connection destination of the one end part 61a of the condensed water passage 60A in the condensed water treatment mechanism 60 is the lowest part 10a, the connection destination is the part with the lowest vertical height (lowest part) in the intercooler 22. It may be connected to. In this case, the condensed water that tends to accumulate in the lowest part of the intercooler 22 is appropriately processed by the condensed water treatment mechanism 60.
Further, instead of the turbocharger 50, a supercharger driven by the output shaft of the engine 1 may be used.

  Further, the regeneration pipe 66 may be omitted, and the regeneration switching valve 67 may be omitted accordingly. In this case, since the filter 68 cannot be regenerated, it is preferable to use a replaceable filter. Furthermore, the on-off valve 64 can also be omitted.

  In the above-described embodiment, the other end portion 61b of the condensed water passage 60A of the condensed water treatment mechanism 60 is connected to the downstream side of the exhaust treatment devices 40 and 41. 40 and 41 may be upstream. In this case, the condensed water discharged to the exhaust passage 30 </ b> A flows through the exhaust treatment devices 40 and 41, and thus the filter 68 may be omitted from the condensed water treatment mechanism 60.

  In the above-described embodiment, the slit 11 is formed in the lowest portion 10a of the intake pipe 10. However, instead of or in addition to the slit 11, a pore having an arbitrary shape such as a round hole or a long hole is formed. May be. Such pores are provided in a size or arrangement that does not hinder the flow of intake air along the intake pipe 10. Also in this case, the condensed water can be introduced into the condensed water treatment mechanism 60 without disturbing the flow of the intake air.

Further, in place of or in addition to the linear air-fuel ratio sensor 93, an O ₂ sensor may be attached to the intake manifold 19.
Moreover, although the diesel engine was mentioned as an example and mentioned above, it may replace with this and may use a gasoline engine. In this case, not only gasoline is used as the fuel, but also the configuration of the injector, the post-processing device, etc. corresponds to the gasoline engine.

  The condensed water treatment mechanism of the present invention can be applied to a vehicle such as an automobile equipped with an engine and its intake / exhaust system.

1 Engine 5 Combustion chamber 10 Intake pipe 10a Minimum part 10A Intake passage 11 Slit 19 Intake manifold 22 Intercooler 23 Second throttle valve 30 Exhaust pipe 30A Exhaust passage 39 Exhaust manifold 40 Primary exhaust treatment device 41 Secondary exhaust treatment device 50 Turbocharger (Supercharger)
51 Low Pressure EGR System 52 High Pressure EGR System 60 Condensed Water Treatment Mechanism 60A Condensed Water Passage 61A First Condensed Water Passage 61B Second Condensed Water Passage 61C Third Condensed Water Passage 61 Condensed Water Pipe 61a One End 61b Other End 62 Tank (Reservoir) )
63 Back pressure switching valve 64 On-off valve 65 Back pressure piping 65A Back pressure passage 66 Regeneration piping 66A Regeneration passage 67 Regeneration switching valve 68 Filter 93 Linear air-fuel ratio sensor 100 Controller

Claims (6)

An intercooler that is interposed downstream of a supercharger that supercharges intake air in an intake passage of the engine and cools the intake air supercharged by the supercharger;
An EGR passage connecting the exhaust passage of the engine and the upstream side of the supercharger of the intake passage;
One end portion is connected to the intercooler of the intake passage or downstream from the intercooler, the other end portion is connected to the exhaust passage, and a condensed water passage through which condensed water generated by the intercooler flows,
A storage unit interposed in the condensed water passage and storing the condensed water;
A back pressure switching valve interposed on the one end side of the condensed water passage from the storage portion of the condensed water passage;
A back pressure passage having one end connected to the exhaust passage and the other end connected to the back pressure switching valve;
The back pressure switching valve is
A state in which the one end of the condensed water passage communicates with the storage portion, and a state in which communication between the exhaust passage and the storage portion via the back pressure passage is interrupted;
Condensation characterized in that communication between the one end portion of the condensed water passage and the storage portion is interrupted and a state in which the exhaust passage and the storage portion are connected via the back pressure passage is switched. Water treatment mechanism. An exhaust treatment device that is interposed in the exhaust passage and purifies the exhaust ;
A filter that is disposed closer to the other end of the condensed water passage than the storage portion of the condensed water passage, and purifies the condensed water;
A regeneration switching valve interposed between the storage section of the condensed water passage and the filter;
A regeneration passage having one end connected to the exhaust passage and the other end connected to the regeneration switching valve;
The one end portion of the back pressure passage is connected to a downstream side of the exhaust treatment device of the exhaust passage,
The filter is a regenerative filter capable of regenerating the purification capacity by heating,
The regeneration switching valve is
A state in which the reservoir and the exhaust passage through the filter are communicated, and the communication between the one end of the regeneration passage and the exhaust passage through the filter is blocked;
The communication between the storage portion and the exhaust passage via the filter is blocked, and the state where the one end of the regeneration passage and the exhaust passage via the filter are communicated is switched,
The exhaust treatment device has a primary exhaust treatment device with a temperature raising function and a secondary exhaust treatment device that is disposed downstream of the primary exhaust treatment device and purifies exhaust gas,
The one end portion of the regeneration passage is connected to a downstream side of the primary exhaust treatment device and an upstream side of the secondary exhaust treatment device of the exhaust passage , The condensed water treatment mechanism according to claim 1. The condensed water treatment mechanism according to claim 2 , wherein the one end portion of the back pressure passage is connected to a downstream side of the secondary exhaust treatment device of the exhaust passage. 4. The condensed water treatment mechanism according to claim 2 , further comprising a valve that is interposed between the storage section in the condensed water passage and the switching valve for regeneration and that can adjust an opening degree. 5. The condensed water treatment according to any one of claims 1 to 4 , wherein the one end portion of the condensed water passage is a slit or a pore formed in an intake pipe that forms the intake passage. mechanism. The one end portion of the condensed water passage, characterized in that the vertical height among the intake passage is connected to the lowest part, the condensate processing mechanism according to any one of claims 1 to 5 .

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