JP6155892B2 - 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 to 3.

  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.

  Patent Document 3 is provided with a condensed water removal passage that communicates the bottom portion of the intercooler with the intake passage downstream of the intercooler, and the intake passage between the upstream end and the downstream end of the condensed water removal passage is provided. A throttle valve is shown. By adjusting the opening of the throttle valve, a differential pressure is generated between the upstream end and the downstream end of the condensed water removal passage under a predetermined condition that does not interfere with the condensed water flowing into the combustion chamber. By treating it, it is said that condensed water can be removed while suppressing damage to the engine and deterioration of drivability.

JP 2012-189022 A Japanese Patent No. 3666583 JP 2012-140868 A

  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. Further, in the technique of Patent Document 3, since there is no configuration for storing condensed water, condensed water that does not fit in the condensed water removal passage may be rolled up 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 downstream side of the one end of the intake passage, the condensed water passage through which the condensed water generated by the intercooler flows, and the condensed water passage A storage part that stores the condensed water, and is provided downstream of the storage part of the condensed water passage, and communicates the storage part and the other end of the condensed water passage in an open state. In the closed state with the reservoir An opening and closing valve for blocking the communication between the other end of the water passage, wherein a condensed water passage the reservoir switching valve interposed in the one end side than the, one end portion connected to the exhaust passage, A back pressure passage having the other end connected to the switching valve. The switching valve communicates the one end of the condensed water passage with the reservoir, and shuts off the communication between the exhaust passage and the reservoir via the back pressure passage, and the condensed water. The communication between the one end portion of the passage and the storage portion is blocked, and the state of communication between the exhaust passage and the storage portion via the back pressure passage is switched.

( 2 ) It is preferable to provide a throttle valve interposed between the one end of the condensed water passage and the other end of the condensed water passage of the intake passage.
( 3 ) It is preferable that the said on-off valve is a valve which can adjust the opening degree.
( 4 ) 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.
( 5 ) 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 downstream side of the intercooler of 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 condensate passage downstream of the reservoir is in communication with the reservoir and the other end of the condensed water passage in the open state, and communication between the reservoir and the other end of the condensate passage is closed in the closed state. If there is no problem even if the condensed water is discharged into the intake passage because the on-off valve is installed (for example, if there is no problem even if the condensed water flows into the combustion chamber), the on-off valve can be opened. Condensed water is discharged into the intake passage, and if the condensate is discharged into the intake passage, it will cause trouble (for example, if the condensate flows into the combustion chamber, it will cause trouble). Since water is stored in the storage part without being discharged, the condensed water can be appropriately treated.
In this way, since the condensate is stored in the condensate passage and the on-off valve disposed downstream of the condensate is stored in the condensate passage, the condensate is prevented from being rolled up and appropriately treated. can do.

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 condensation is described later on each of the upstream and downstream sides of the second throttle valve 23. A water treatment mechanism 60 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, and the amount of condensed water discharged from the condensed water treatment mechanism 60 described later is 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. A condensed water treatment mechanism 60 is connected to the intake manifold 19 downstream of the linear air-fuel ratio sensor 93.

[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, and a back pressure pipe 65 of a condensed water treatment mechanism 60 described later is connected to the downstream side.
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.

A low pressure EGR pipe 51c of the low pressure EGR 51 is connected downstream of the primary exhaust treatment device 40 and upstream of the secondary exhaust treatment device 41.
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.

[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 exhaust 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 upstream side of the back pressure pipe 65 of the condensed water treatment mechanism 60. 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 that is to be stored in the lowest portion 10a is guided and stored outside the intake passage 10A, and the condensed water is supplied to the intake passage 10A when there is no problem even if the condensed water flows into the combustion chamber 5. It is for discharging.

  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 (reservoir) 62 that stores condensed water, a switching valve 63, and an on-off valve. 64 and a back pressure pipe 65 that forms a back pressure passage 65A therein. The condensed water pipe 61 is provided with a switching valve 63, a tank 62, and an on-off valve 64 in the order in which the condensed water flows. A back pressure pipe 65 is connected to the switching valve 63.

In the following description, the condensed water passage 60A is divided into three parts. Specifically, the first condensed water passage 61 </ b> A to the switching valve 63, the second condensed water passage 61 </ b> B from the switching valve 63 to the tank 62, and the third condensation downstream from the tank 62 in the order in which the condensed water flows. The description will be made in three parts with the water passage 61C.
Hereinafter, each structure is demonstrated in order of the condensed water pipe | tube 61, the tank 62, the switching valve 63, the piping 65 for back pressure, and the on-off valve 64.

  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 portion 61 b of the water passage 60 </ b> A) is connected to the intake manifold 19. The second throttle valve 23 is provided between one end 61a and the other end 61b of the condensed water passage 60A formed by the condensed water pipe 61 in the intake passage 10A. Accordingly, one end 61a of the condensed water passage 60A is connected to the upstream side of the second throttle valve 23 of the intake passage 10A, and the other end 61b of the condensed water passage 60A is connected to the second throttle valve 23 of the intake passage 10A. Is also connected downstream.

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 switching valve 63 is interposed between the end of the condensed water pipe 61 on the side where the condensed water flows (one end 61a of the condensed water passage 60A) and the tank 62, that is, the third condensed water passage 61C. A first inflow connection portion 63a and a second inflow connection portion 63b are provided as two side connection portions on the side, and an outflow connection portion 63c is provided as a connection portion on the outflow side. In the switching valve 63, (i) one of the inflow connection portions 63a and 63b and the outflow connection portion 63c are communicated with each other, and the other of the inflow connection portions 63a and 63b and the outflow connection portion 63c are disconnected. And (ii) switching between 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.

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 63c.
Therefore, the switching valve 63 is in a state in which (i) the first condensed water passage 61A and the second condensed water passage 61B are communicated, and the communication between the back pressure passage 65A and the second condensed water passage 61B is blocked. And (ii) the communication 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 has become.

In other words, the switching valve 63 (i) communicates the one end portion 61a of the condensed water passage 60A with the tank 62 and blocks communication between the exhaust passage 30A and the tank 62 via the back pressure passage 65A ( (Hereinafter referred to as “reserved state”), and (ii) the communication between the one end portion 61a of the condensed water passage 60A and the tank 62 is blocked, and the exhaust passage 30A and the tank 62 are communicated via the back pressure passage 65A. The state (hereinafter referred to as “discharge state”) can be switched.
The back pressure pipe 65 has one end portion 65 a that is an end portion on the exhaust gas inflow side connected to the exhaust manifold 39, and the other end portion 65 b that is an end portion on the exhaust gas outflow side is connected to the switching valve 63. Yes.

The on-off valve 64 is interposed between the tank 62 and the end of the condensed water pipe 61 on the side where the condensed water flows out (the other end 61b of the condensed water passage 60A). The open / close valve 64 communicates with the third condensed water passage 61C (between the other end 61b of the condensed water passage 60A and the tank 62) in the open state, and blocks communication between the third condensed water passage 61C in the closed state. Is.
Furthermore, the on-off valve 64 is a valve whose opening degree can be adjusted. Depending on the opening degree of the on-off valve 64, the degree of circulation (discharge degree) of the condensed water at the place where the on-off valve 64 is disposed is adjusted.

[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 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 based on 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 or the second throttle valve 23 and switching the switching valve 63. Hereinafter, the storage control for storing the condensed water and the discharge control for discharging the condensed water will be described for the control of the condensed water treatment mechanism 60.

[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 switching valve 63 makes the above (i) storage state, and the on-off valve 64 is closed. In the storage control, the second throttle valve 23 is not controlled, and the throttle opening 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. Here, two discharge controls of the first discharge control and the second discharge control will be described.
In both the first discharge control and the second discharge control, the on-off valve 64 is opened. The opening and closing of the on-off valve 64 is adjusted according to the degree of condensed water discharge. In the following description, differences between the first discharge control and the second discharge control will be described.

In addition, when 1st discharge control is implemented, 2nd discharge control is not implemented, conversely, when 2nd execution control is implemented, 1st discharge control is not implemented.
In the first discharge control, the switching valve 63 causes the discharge state (ii). In the first discharge control, the second throttle valve 23 is not controlled, and the throttle opening is arbitrary.

  In the second discharge control, the switching valve 63 causes the storage state (i). Further, in the second discharge control, the opening degree of the second throttle valve 23 is adjusted so that the intake pressure at the one end 61a is higher than the intake pressure at the other end 61b of the condensed water treatment mechanism 60. As a result, the intake pressure at one end 61a is made higher than the intake pressure at the other end 61b of the condensed water passage 60A, and a differential pressure is generated between both ends. For example, the differential pressure can be generated by reducing the opening of the second throttle valve 23.

[1-3-2-2-3. Control 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 when performing storage control and discharge control. 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.
The control device 100 performs storage control if a predetermined condition is satisfied, and performs discharge control if the predetermined condition is not satisfied.

  The predetermined condition is satisfied when the tank 62 is not full of condensed water, and it is difficult to discharge the condensed water to the intake passage 10A. When the condensed water is discharged to the intake passage 10A, the trouble is caused when the condensed water flows into the combustion chamber 5 of the engine 1 and the trouble is caused. Examples of such troubles include low-temperature combustion, idling, and high-load operation of the engine 1.

  If the predetermined condition is not satisfied, either the first discharge control or the second discharge control may be performed. For example, when the differential pressure of the intake air related to the second discharge control cannot be secured, The first discharge control is performed when the amount of the condensed water stored is a predetermined amount or more (for example, half or more of the capacity of the tank 62), and the second discharge control is performed otherwise.

[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 of the third condensed water passage 61C is blocked by the closed on-off valve 64, the condensed water stored in the tank 62 is not discharged into the intake passage 10A formed by the intake manifold 19. Absent.

  Further, since the exhaust pressure is usually higher than the intake pressure, when the first exhaust control is performed, the exhaust pressure in the exhaust passage 30A via the back pressure passage 65A is stored in the tank 62. The back pressure pushes out the condensed water. At this time, since the third condensed water passage 61C is communicated by the open / close valve 64, the condensed water stored in the tank 62 is pushed out by the back pressure and discharged to the intake passage 10A formed by the intake manifold 19. Is done.

Further, when the second discharge control is performed, the condensed water passage 60A (the first condensed water passage 61A, the second condensed water passage 61B, and the third condensed water passage 61C) is in communication and is therefore stored in the tank 62. The condensed water is pushed by the intake pressure (differential pressure) at the one end 61 a that is higher than the intake pressure at the other end 61 b of the condensed water treatment mechanism 60, and is discharged into the intake passage 10 </ b> A formed by the intake manifold 19.
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.

  If the predetermined condition is not satisfied, the first discharge control or the second discharge control in which the on-off valve 64 is opened is performed, so that the condensed water is discharged to the intake passage 10A formed by the intake manifold 19, Further, if the predetermined condition is satisfied, the condensate is stored in the tank 62 without being discharged by performing the storage control in which the on-off valve 64 is closed, so that the condensate is appropriately processed. can do.

As described above, the condensate water storage tank 60 and the on-off valve 64 interposed downstream thereof are provided in the condensate water passage 60A, thereby preventing the condensate water from being rolled up and appropriately condensing water. Can be processed.
Further, when the condensed water is discharged into the intake passage 10A, the intake air mixed with the condensed water is combusted in the combustion chamber 5, so that the temperature at the time of combustion decreases, so that NOx or smoke can be reduced. .

  When the first discharge control is performed, the switching valve 63 is set to the discharge state (ii) and the open / close valve 64 is opened, so that the exhaust pressure of the exhaust passage 30A via the back pressure passage 65A is increased. Since the back pressure pushes out the condensed water stored in the tank 62, the condensed water stored in the tank 62 can be reliably discharged to the intake passage 10 </ b> A formed by the intake manifold 19.

If the second discharge control is performed, the condensed water passage 60A is adjusted by adjusting the opening of the second throttle valve 23 provided between the one end portion 61a and the other end portion 61b of the condensed water passage 60A. Since the intake pressure at the one end 61a is higher than the intake pressure at the other end 61b, the condensed water can be discharged.
Since the opening / closing valve 64 is a valve whose opening degree can be adjusted, the degree of condensed water discharge can be adjusted when the first discharge control and the second discharge control are performed. Thereby, condensed water can be processed further appropriately.

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.

  Thus, since the flow of the condensed water in the intake passage 10A between the one end portion 61a and the other end portion 61b of the condensed water treatment mechanism 60 is avoided, the intake passage between the one end portion 61a and the other end portion 61b. It is possible to prevent the linear air-fuel ratio sensor 93 provided in 10A from being wetted. In other words, it is possible to prevent the various devices provided in the intake passage 10A between the one end portion 61a and the other end portion 61b from being wetted. As a result, the durability and reliability of the various devices. Can be secured.

[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 back pressure pipe 65 may be omitted, and the switching valve 63 may be omitted in accordance with this. In this case, when the condensed water is discharged, only the second discharge control for adjusting the opening of the second throttle valve 23 is performed.

The second throttle valve 23 may be omitted. In this case, the condensed water can be discharged by performing the first discharge control. Even if the second throttle valve 23 is omitted, the open / close valve 64 is opened when the intake pressure at the one end 61a is higher than the intake pressure at the other end 61b of the condensed water treatment mechanism 60. Can be discharged, and the second discharge control can be performed. At this time, for example, by adjusting the opening degree of the high pressure EGR valve 52e, it is possible to increase the execution accuracy of the second discharge control.
In addition, the on / off valve 64 is configured as a valve whose opening degree can be adjusted, but the on / off valve 64 is a two-way valve in which the on / off state is switched between an open state and a closed state. There may be.

  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 portion 10A Intake passage 11 Slit 19 Intake manifold 22 Intercooler 23 Second throttle valve 30 Exhaust pipe 30A Exhaust passage 39 Exhaust manifold 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 switching valve 63a first inflow connection portion 63b second inflow connection portion 63c outflow connection portion 64 on-off valve 65 back pressure piping 65A back pressure passage 65a one end portion 65b other end portion 93 linear air-fuel ratio sensor 100 control device

Claims (5)

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 is connected to the downstream side of the intercooler or the intercooler of the intake passage, the other end portion is connected to the downstream side of the one end portion of the intake passage, and condensed water generated by the intercooler. A condensed water passage through which
A storage unit interposed in the condensed water passage and storing the condensed water;
The condensate water passage is interposed downstream of the storage portion, communicates the storage portion with the other end of the condensate water passage in the open state, and closes the storage portion and the condensate water passage in the closed state. An on-off valve that blocks communication with the other end;
A switching valve interposed closer to the one end than the reservoir of the condensed water passage;
A back pressure passage having one end connected to the exhaust passage and the other end connected to the switching valve;
The 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;
The communication between the one end portion of the condensed water passage and the storage portion is cut off, and the state of switching between the exhaust passage and the storage portion via the back pressure passage is switched. Condensate treatment mechanism . Wherein characterized by comprising the interposed throttle valve between the end portion of the condensed water passage and the other end of the condensed water passage, the condensed water treatment of claim 1 Symbol placement of the intake passage mechanism. The on-off valve is characterized in that an adjustable valve the opening, according to claim 1 or 2 condensed water processing mechanism according. The one end portion of the condensed water passage, and said a slit or pores formed in the intake pipe forming the intake passage, the condensed water treatment according to any one of claims 1 to 3 mechanism. The one end portion of the condensed water passage, characterized in that the vertical height among the downstream side of the intercooler of the intake passage is connected to the lowest portion, or any claim 1-4 1 Condensate treatment mechanism according to item.

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