JP2006226187A - Exhaust emission control system of transverse v-engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method to suitably supply a reducing agent to an exhaust emission control means installed into an exhaust passage in an exhaust emission control system of a transverse V-engine. <P>SOLUTION: In the exhaust emission control system of the transverse V-engine 1, a front side exhaust gas passage 11a and a back side exhaust gas passage 11b which are extended backward are connected with each other near a back side bank 5a or at the back. The exhaust emission control means 14 is installed in an exhaust passage 11c downstream from the connection portion. In this case, a reducing agent adding valve 18 to supply a reducing agent into the exhaust emission control means 14 is installed in an exhaust gas manifold 9a of the front side bank 5a or an exhaust gas port 7 of a cylinder 4 belonging to the front side bank 5a. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an exhaust emission control device for a laterally placed V-type engine that is disposed sideways with respect to a vehicle.

  Patent Document 1 discloses a technology related to an exhaust purification device for a multi-cylinder internal combustion engine. In this exhaust purification device, an open / close valve is provided in the exhaust passage of each cylinder row, and the upstream side of the open / close valve in each cylinder row is connected by a communication passage. Further, a first catalyst is provided downstream of the on-off valve in the exhaust passage of one cylinder row, a portion of the exhaust passage of one cylinder row downstream from the first catalyst, and the other cylinder row A portion of the exhaust passage downstream of the on-off valve is joined. And the 2nd catalyst is provided in the exhaust passage downstream from this junction part.

Patent Document 2 discloses a technique related to an exhaust purification device having a NOx catalyst provided in an exhaust passage of an internal combustion engine. In this exhaust purification device, the cylinder head of the internal combustion engine is provided with a reducing agent injection means for injecting a reducing agent toward the exhaust passage, and further, the reducing agent in the exhaust is supplied to the exhaust passage upstream of the NOx catalyst. A stirrer for stirring is provided.
JP-A-8-121153 JP 2001-65333 A JP-A-5-87002 JP-A-6-221966 JP 2001-280125 A

  In an exhaust gas purification apparatus for an internal combustion engine, as an exhaust gas purification means provided in an exhaust passage, an NOx storage reduction catalyst (hereinafter simply referred to as NOx catalyst) for purifying NOx in exhaust gas, or particulate matter in exhaust gas (hereinafter referred to as NOx catalyst) A particulate filter (hereinafter simply referred to as a filter) or the like that collects PM) is used.

  When a NOx catalyst is used as the exhaust purification means, it is necessary to supply a reducing agent to the NOx catalyst in order to reduce NOx and SOx stored in the NOx catalyst. In addition, when a catalyst having an oxidation function and a filter are used in combination as exhaust purification means, the catalyst having an oxidation function is disposed upstream of the filter or carried by the filter. Even in such a case, it is necessary to supply a reducing agent to the catalyst having an oxidation function in order to oxidize and remove the PM collected by the filter.

  As a method of supplying the reducing agent to the exhaust purification means as described above, there is a method of adding the reducing agent from the reducing agent addition valve to the exhaust system upstream of the exhaust purification means. In such a method, it is important to atomize and diffuse the reducing agent added from the reducing agent addition valve in the exhaust gas.

  Further, when a horizontally mounted V-type engine installed horizontally with respect to the vehicle is used as an internal combustion engine, a front exhaust passage connected to the exhaust manifold of the front bank extends rearward. The front exhaust passage and the rear exhaust passage connected to the exhaust manifold of the rear bank are connected to each other near or behind the rear bank.

  In such an exhaust purification device for a horizontal V-type engine, the exhaust purification means as described above may be provided in the exhaust passage downstream of the connecting portion between the front exhaust passage and the rear exhaust passage.

  It is an object of the present invention to provide a technique capable of more suitably supplying a reducing agent to an exhaust gas purification unit provided in an exhaust passage in an exhaust gas purification device for a horizontal V-type engine.

  In the present invention, in the horizontally mounted V-type engine, the front exhaust passage and the rear exhaust passage extending rearward are connected to each other near or behind the rear bank, Exhaust gas purifying means is provided in the exhaust passage downstream of the connecting portion. In such a case, a reducing agent addition valve for supplying a reducing agent to the exhaust purification means is installed in the exhaust manifold of the front bank or the exhaust port of the cylinder belonging to the front bank.

More specifically, an exhaust emission control device for a horizontally mounted V-type engine according to the present invention includes:
The other end of the front exhaust passage that is connected to the exhaust manifold of the front bank and extends rearward, and the other end of the rear exhaust passage that is connected to the exhaust manifold of the rear bank. Are connected to each other in the vicinity of or behind the rear bank, and to one end of a main exhaust passage for discharging exhaust gas from the other end to these connecting portions. A purification device,
The NOx storage reduction catalyst is included, or includes a particulate filter, and a catalyst having an oxidation function that is disposed upstream of the particulate filter or is supported by the particulate filter. An exhaust gas purification means comprising:
A reducing agent addition valve for adding a reducing agent to the exhaust,
The exhaust purification means is provided in the main exhaust passage;
The reducing agent addition valve is provided in an exhaust manifold of the front bank or an exhaust port of a cylinder belonging to the front bank.

  In the present invention, the front side exhaust passage extends rearward. That is, the front exhaust passage extends toward the rear bank. The other end of the front exhaust passage and the other end of the rear exhaust passage are connected to each other near or behind the rear bank. Therefore, the front side exhaust passage is longer than the rear side exhaust passage.

  Further, the exhaust purification means is provided in the main exhaust passage downstream from the connecting portion between the front exhaust passage and the rear exhaust passage. Accordingly, the distance from the exhaust manifold of the front bank (hereinafter referred to as the front exhaust manifold) to the exhaust purification means is the distance from the exhaust manifold of the rear bank (hereinafter referred to as the rear exhaust manifold) to the exhaust purification means. Inevitably longer than.

  Therefore, in the present invention, the reducing agent addition valve is installed in the exhaust port of the cylinder belonging to the front side exhaust manifold or the front side bank. As a result, the distance from the reducing agent addition valve to the exhaust gas purification means can be made as long as possible. As a result, the reducing agent added from the reducing agent addition valve is diffused in the exhaust gas until it reaches the exhaust gas purification means. Further, since the distance from the reducing agent addition valve to the exhaust purification unit becomes longer, the time from when the reducing agent is added until the reducing agent reaches the exhaust purification unit becomes longer. Therefore, atomization of the reducing agent is further promoted.

In other words, according to the present invention, the reducing agent can be more suitably supplied to the exhaust gas purification means provided in the exhaust passage in the exhaust gas purification apparatus for the horizontal V-type engine.

  In the present invention, when a plurality of cylinders are provided in the front bank and a reducing agent addition valve is provided in an exhaust port of a cylinder belonging to the front bank, a connection portion with the other end of the front exhaust passage in the exhaust manifold A reducing agent addition valve may be provided at the exhaust port of the cylinder adjacent to the cylinder.

  By providing the reducing agent addition valve at the exhaust port of such a cylinder, the reducing agent added from the reducing agent addition valve is more forward than when the reducing agent addition valve is provided at the exhaust port of another cylinder. It becomes easy to be introduced into the exhaust passage. Therefore, it is possible to prevent the reducing agent from flowing into another cylinder not provided with the reducing agent addition valve.

  In this invention, you may further provide the heat insulation means which insulates at least one part of a front side exhaust passage.

  According to such a configuration, it is possible to suppress the temperature drop of the exhaust gas flowing in the front side exhaust passage. Therefore, atomization of the reducing agent in the front side exhaust passage can be further promoted. Further, when the temperature of the exhaust gas purification means is raised, it can be raised earlier.

  In the present invention, when an EGR device that introduces part of the exhaust gas into the intake system via the EGR passage is further provided, the EGR passage may be connected to the rear exhaust manifold.

  In the present invention, the reducing agent is added to the exhaust port of the cylinder belonging to the front exhaust manifold or the front bank. Therefore, by connecting the EGR passage to the rear exhaust manifold to which no reducing agent is added, the mixing of the reducing agent into the EGR gas can be suppressed.

  In the present invention, when the EGR device is further provided, one end of the rear exhaust passage is connected to one side portion of the rear exhaust manifold, and the EGR passage is connected to the other side portion of the rear exhaust manifold. May be.

  According to such a configuration, the connection position of the EGR passage in the rear exhaust manifold can be set as far as possible from the connection position with the rear exhaust passage. As a result, even when the reducing agent flows into the rear exhaust manifold via the rear exhaust passage, the mixing of the reducing agent into the EGR gas can be suppressed.

  According to the present invention, in the exhaust purification device for a horizontal V-type engine, the reducing agent can be more suitably supplied to the exhaust purification means provided in the exhaust passage.

  Hereinafter, specific embodiments of an exhaust emission control device for a horizontal V-type engine according to the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing a schematic configuration of an internal combustion engine and its intake / exhaust system according to the present invention. The internal combustion engine 1 is a horizontal V-type 6-cylinder diesel engine that is installed horizontally in the engine room 3 of the vehicle 2 with respect to the vehicle 2. Here, in the internal combustion engine 1, the bank 5a on the front side of the vehicle 2 is referred to as a front bank 5a, and the bank 5b on the rear side of the vehicle 2 is referred to as a rear bank 5b. Three cylinders 4 are provided in each of the front bank 5a and the rear bank 5b. In FIG. 1, the upper direction is the forward direction of the vehicle 2.

  A front exhaust manifold 9a is connected to the front side of the front bank 5a in the internal combustion engine 1, and a front intake manifold 8a is connected to the rear side of the front bank 5a. Further, a rear intake manifold 8b is connected to the front side of the rear bank 5b in the internal combustion engine 1, and a rear exhaust manifold 9b is connected to the rear side of the rear bank 5b. That is, the front and rear intake manifolds 8a and 8b are disposed inside the V-shape formed by the front bank 5a and the rear bank 5b, and the front and rear exhaust manifolds 9a and 9b are disposed outside the V-shape. Is arranged.

  An intake port 6 of each cylinder 4 belonging to the front bank 5a is connected to the front intake manifold 8a, and an exhaust port 7 of each cylinder 4 belonging to the front bank 5a is connected to the front exhaust manifold 9a. Yes. The intake port 6 of each cylinder 4 belonging to the rear bank 5b is connected to the rear intake manifold 8b, and the exhaust port 7 of each cylinder 4 belonging to the rear bank 5b is connected to the rear exhaust manifold 9b. Has been.

  One end of the front intake passage 10a is connected to the right end of the front intake manifold 8a. One end of the rear intake passage 10b is connected to the right end of the rear intake manifold 8b.

  The other end of the front intake passage 10 and the other end of the rear intake passage 10 b are connected to each other on the right side of the internal combustion engine 1. Furthermore, one end of a main intake passage 10c through which intake air is drawn from the other end is connected to these connecting portions.

  One end of the front exhaust passage 11a is connected to the left end of the front exhaust manifold 9a. The front exhaust passage 11a extends rearward. That is, the front side exhaust passage 11a extends in the direction of the rear side bank 5b.

  A part of the front side exhaust passage 11 a has a double pipe structure surrounded by the outer pipe 19. FIG. 2 is a view showing a cross section of a portion having a double pipe structure in the front side exhaust passage 11a. The outer tube 19 is provided with a space between its inner wall surface and the outer wall surface of the front side exhaust passage 11a. Therefore, an air layer 20 (shaded portion in FIG. 2) is formed between the outer wall surface of the front side exhaust passage 11 a and the inner wall surface of the outer tube 19. That is, the portion having the double pipe structure has a heat insulating structure that is thermally insulated by the air layer 20.

  On the other hand, one end of the rear exhaust passage 11b is connected to the left end of the rear exhaust manifold 9b. The other end of the front exhaust passage 11a extending toward the rear bank 5b and the other end of the rear exhaust passage 11b are on the left side of the internal combustion engine 1, and are located behind the rear bank 5b. They are connected to each other in the vicinity of the rear bank 5b. Furthermore, one end of the main exhaust passage 11c from which the exhaust is discharged from the other end is connected to these connecting portions.

  A turbocharger turbine 12 is provided in the main exhaust passage 11c. Further, a catalytic converter 13 is provided in the main exhaust passage 11 c on the downstream side of the turbine 12. A NOx catalyst 14 is installed in the catalytic converter 13. The NOx catalyst 14 is a catalyst that stores NOx in the exhaust when the ambient atmosphere is an oxidizing atmosphere, and reduces the stored NOx when the ambient atmosphere is a reducing atmosphere and the temperature is equal to or higher than the NOx reducible temperature. is there.

Further, a fuel addition valve 18 for adding fuel as exhaust gas into the exhaust is installed in the vicinity of the connection portion between the front exhaust manifold 9a and the front exhaust passage 11a. The fuel addition valve 18 is provided so that fuel is added toward the front side exhaust passage 11a.

  Further, the internal combustion engine 1 is provided with an EGR device 15 for introducing a part of the exhaust gas into the intake system. The EGR device 15 includes an EGR passage 16 and an EGR valve 17.

  One end of the EGR passage 16 is connected to the right end of the rear exhaust manifold 9b. That is, the EGR passage 16 is connected to the end of the rear exhaust manifold 9b opposite to the connection portion with the rear exhaust passage 11b. The other end of the EGR passage 16 is connected to the main intake passage 10c. An EGR valve 17 for adjusting the amount of EGR gas flowing through the EGR passage 16 is provided in the middle of the EGR passage 16.

  The internal combustion engine 1 configured as described above is provided with an ECU (not shown) for controlling the internal combustion engine 1. The fuel addition valve 18 and the EGR valve 17 are electrically connected to the ECU and controlled by the ECU.

  For example, in this embodiment, when NOx stored in the NOx catalyst 14 is reduced and when SOx stored in the NOx catalyst 14 is reduced, the fuel addition valve 18 is supplied to supply fuel to the NOx catalyst 14. Fuel is added from.

  As described above, in the present embodiment, the front exhaust passage 11a extends rearward, and the front exhaust passage 11a and the rear exhaust passage 11b are located rearward and rearward of the rear bank 5b. They are connected to each other in the vicinity of the side bank 5b. Therefore, the front side exhaust passage 11a is longer than the rear side exhaust passage 11b.

  Further, the NOx catalyst 14 is provided in the main exhaust passage 11c which is downstream from the connecting portion between the front side exhaust passage 11a and the rear side exhaust passage 11b. Therefore, the distance from the front exhaust manifold 9a to the NOx catalyst 14 is necessarily longer than the distance from the rear exhaust manifold 9b to the NOx catalyst 14.

  And the fuel addition valve 18 is installed in the front side exhaust manifold 9a. Thereby, the distance from the fuel addition valve 18 to the NOx catalyst 14 can be made as long as possible. As a result, the fuel added from the fuel addition valve 18 is diffused in the exhaust gas until reaching the NOx catalyst 14. Further, since the distance from the fuel addition valve 18 to the NOx catalyst 14 becomes longer, the time from when the fuel is added until the fuel reaches the NOx catalyst 14 becomes longer. Therefore, atomization of fuel is further promoted.

  That is, according to the present embodiment, in the horizontally-placed V-type engine, the fuel as the reducing agent can be more suitably supplied to the NOx catalyst 14 provided in the main exhaust passage 11c. As a result, NOx and SOx stored in the NOx catalyst 14 can be reduced more efficiently. Moreover, the adhesion of fuel to the front side exhaust passage 11a can also be suppressed. As a result, fuel consumption can be improved and deterioration of exhaust emission can be suppressed.

  Further, according to this embodiment, the distance from the fuel addition valve 18 to the turbine 12 of the turbocharger is inevitably longer. Therefore, the fuel added from the fuel addition valve 18 is further diffused and atomized until it reaches the turbine 12. Therefore, it is possible to suppress the adhesion of fuel to the turbine 12.

Further, in this embodiment, the fuel addition valve 18 is provided in the vicinity of the connection portion of the front exhaust passage 11a in the front exhaust manifold 9a so that fuel is added toward the front exhaust passage 11a. .

  Thereby, the fuel added from the fuel addition valve 18 is easily introduced into the front exhaust passage 11a. Therefore, fuel can be prevented from flowing into the cylinders 4 belonging to the front bank 5a via the exhaust port 7.

  In addition, according to the present embodiment, a part of the front side exhaust passage 11a has a double-pipe structure, thereby providing a heat insulating structure. Thereby, the temperature fall of the exhaust_gas | exhaustion which flows through the inside of the front side exhaust passage 11a can be suppressed. Therefore, atomization of the reducing agent in the front side exhaust passage 11a can be further promoted. Further, when the temperature of the NOx catalyst 14 is raised, it can be raised earlier.

  In addition, since exhaust gas is newly introduced through the rear exhaust passage 11b in the downstream side of the connecting portion between the front exhaust passage 11a and the rear exhaust passage 11b, that is, in the main exhaust passage 11c, the front exhaust passage Compared to 11a, the exhaust temperature is less likely to decrease. Therefore, it is more important to suppress the temperature drop of the exhaust in the front side exhaust passage 11a. Moreover, it is good also as a structure which covered at least one part of the front side exhaust passage 11a with the heat insulating material instead of setting it as a double pipe structure.

  Further, according to the present embodiment, the EGR passage 16 is connected to the rear exhaust manifold 9b in which the fuel addition valve 18 is not provided. Therefore, it is possible to suppress the fuel added from the fuel addition valve 18 from being mixed into the EGR gas.

  Further, according to the present embodiment, the EGR passage 16 is connected to the end of the rear exhaust manifold 9b opposite to the connection portion with the rear exhaust passage 11b. Thereby, the connection position of the EGR passage 16 in the rear exhaust manifold 9b can be set as far as possible from the connection position with the rear exhaust passage 11b. As a result, even when the fuel added from the fuel addition valve 18 flows into the rear side exhaust manifold 9b via the rear side exhaust passage 11b, mixing of the fuel into the EGR gas can be further suppressed.

  In the present embodiment, a fuel addition valve 18 may be provided in the exhaust port 7 of any cylinder 4 belonging to the front bank 5a. Even with such a configuration, the distance from the fuel addition valve 18 to the NOx catalyst 14 can be made as long as possible.

  In this case, a fuel addition valve 18 may be provided in the exhaust port 7 of the cylinder 4 in the vicinity of the connection portion of the front exhaust passage 11a in the front exhaust manifold 9a. By installing the fuel addition valve 18 at such a position, the fuel added from the fuel addition valve 18 is exhausted to the front side as compared with the case where the fuel addition valve 18 is provided in the exhaust port 7 of the other cylinder 4. It becomes easy to introduce into the passage 11a. Therefore, it is possible to suppress the fuel from flowing into the other cylinder 4 where the fuel addition valve 18 is not provided.

  As described above, when the fuel addition valve 18 is installed in the exhaust port 7, it is preferable to provide the fuel addition valve 18 so that fuel is added toward the front exhaust manifold 9a.

  In this embodiment, a filter carrying the NOx catalyst 14 or the oxidation catalyst may be installed in the catalytic converter 13. In addition, as shown in FIG. 3, both the NOx catalyst 14 and the filter 21 may be separately installed in the catalytic converter 13. In this case, the NOx catalyst 14 is arranged on the upstream side along the flow of the exhaust, and the filter 21 is installed on the downstream side. In addition, the arrow of FIG. 3 represents the direction through which exhaust_gas | exhaustion flows. In the case of the configuration shown in FIG. 3, an oxidation catalyst may be installed instead of the NOx catalyst 14.

  As described above, when the filter is provided in the catalytic converter 13, the fuel addition valve for supplying fuel to the NOx catalyst 14 or the oxidation catalyst even when oxidizing and removing the PM collected by the filter. Fuel is added from 18.

  In this case, according to the present embodiment, the fuel as the reducing agent can be more suitably supplied to the NOx catalyst 14 or the oxidation catalyst, so that the PM collected by the filter can be oxidized and removed more efficiently. I can do it.

The figure which shows schematic structure of the internal combustion engine which concerns on the Example of this invention, and its intake-exhaust system. The figure which shows the cross section of the part which becomes the double pipe structure in the front side exhaust passage which concerns on the Example of this invention. In the Example of this invention, the figure which shows both arrangement | positioning at the time of providing both a NOx catalyst and a filter in a catalytic converter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine 2 ... Vehicle 3 ... Engine room 4 ... Cylinder 5a ... Front side bank 5b ... Back side bank 6 ... Intake port 7 ... Exhaust port 8a ... Front Side intake manifold 8b, Rear exhaust manifold 9a, Front exhaust manifold 9b, Rear exhaust manifold 10a, Front intake passage 10b, Rear intake passage 10c, Main intake passage 11a, Front exhaust Passage 11b, rear exhaust passage 11c, main exhaust passage 12, turbine 13, catalytic converter 14, NOx catalyst (NOx storage reduction catalyst)
15. EGR device 16 EGR passage 17 EGR valve 18 Fuel addition valve 19 Outer pipe 20 Air layer 21 Filter (particulate filter)

Claims (5)

The other end of the front exhaust passage that is connected to the exhaust manifold of the front bank and extends rearward, and the other end of the rear exhaust passage that is connected to the exhaust manifold of the rear bank. Are connected to each other in the vicinity of or behind the rear bank, and to one end of a main exhaust passage for discharging exhaust gas from the other end to these connecting portions. A purification device,
The NOx storage reduction catalyst is included, or includes a particulate filter, and a catalyst having an oxidation function that is disposed upstream of the particulate filter or is supported by the particulate filter. An exhaust gas purification means comprising:
A reducing agent addition valve for adding a reducing agent to the exhaust,
The exhaust purification means is provided in the main exhaust passage;
The exhaust purifying apparatus for a horizontal V-type engine, wherein the reducing agent addition valve is provided in an exhaust manifold of the front bank or an exhaust port of a cylinder belonging to the front bank. A plurality of cylinders are provided in the front bank,
Of the cylinders belonging to the front bank, the reducing agent addition valve is provided in an exhaust port of a cylinder adjacent to a connection portion with the other end of the front exhaust passage in the exhaust manifold. The exhaust emission control device for a horizontal V-type engine according to claim 1.   The exhaust purification device for a horizontal V-type engine according to claim 1 or 2, further comprising heat insulating means for insulating at least a part of the front side exhaust passage. An EGR device that introduces part of the exhaust gas into the intake system via the EGR passage;
The exhaust purification device for a horizontal V-type engine according to any one of claims 1 to 3, wherein the EGR passage is connected to an exhaust manifold of the rear bank.   One end portion of the rear exhaust passage is connected to one side portion of the exhaust manifold of the rear bank, and the EGR passage is connected to the other side portion of the exhaust manifold of the rear bank. The exhaust emission control device for a horizontal V-type engine according to claim 4,

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