JP2012225297A - Engine exhaust device - Google Patents

Abstract

A turbine housing 24 and a catalyst 9 of a supercharger 20 are installed in series in an exhaust gas flow direction in the middle of an exhaust passage (3, 5) of an engine 1 and bypass a turbine wheel 21 of the supercharger 20. In the exhaust device configured such that the exhaust port of the bypass passage 31 is opened and closed by the waste gate valve 32, the exhaust gas discharged from the bypass passage 31 can be introduced into the catalyst 9 while being kept at a high temperature.
SOLUTION: Exhaust gas discharged from a bypass passage 31 directly collides with the inside of a peripheral wall portion of the exhaust passage (3, 5) in a region between the turbine housing 24 and a catalyst 9 in the exhaust passage (3, 5). A receiving portion 35 is provided.
[Selection] Figure 2

Description

  In the present invention, a turbocharger turbine housing and a catalyst are installed in series in the exhaust gas flow direction in the middle of the exhaust passage, and the exhaust port of the bypass passage that bypasses the turbine wheel of the supercharger is opened and closed by a waste gate valve. The present invention relates to an exhaust system for an engine having the above structure.

  Conventionally, a turbocharger turbine housing and a catalyst are installed in series in the exhaust gas flow direction in the middle of the engine exhaust passage, and a bypass passage for bypassing the turbocharger turbine wheel is installed in the exhaust passage. A configuration is known in which a waste gate valve for adjusting the bypass amount of exhaust gas is provided at the discharge port of the bypass passage (see, for example, Patent Document 1). In addition, although the said catalyst is not described in patent document 1, generally the said catalyst is installed in the downstream of the exhaust gas flow direction rather than the turbine housing.

JP 2003-293780 A

  Although not described in Patent Document 1, for example, in the exhaust passage, the region between the turbine housing and the catalyst extends in the horizontal direction and then bends approximately 90 degrees and extends downward in the vertical direction. It may be formed in an inverted L shape.

  In the case of such an exhaust passage, the exhaust gas discharged from the bypass passage does not directly collide with the catalyst but easily collides directly with the peripheral wall portion of the exhaust passage. In such a case, a part of the heat of the exhaust gas is transmitted to the peripheral wall portion, and the heat transmitted to the peripheral wall portion is easily released to the atmosphere, so that it is discharged from the bypass passage. The exhaust gas cannot be introduced into the catalyst while being kept at a high temperature.

  In view of such circumstances, the present invention provides a bypass passage in which a turbine housing and a catalyst of a supercharger are installed in series in the exhaust gas flow direction in the middle of an exhaust passage of an engine and bypass the turbine wheel of the supercharger In an engine exhaust system configured to open and close by a waste gate valve, the exhaust gas discharged from the bypass passage can be introduced into the catalyst while being kept at a high temperature.

  In the engine exhaust system according to the present invention, a turbocharger turbine housing and a catalyst are provided in series in the exhaust gas flow direction in the middle of an engine exhaust passage, and the turbocharger turbine wheel is bypassed in the exhaust passage. And a waste gate valve for adjusting a bypass amount of the exhaust gas is provided at an exhaust port of the bypass passage, and the exhaust passage includes a waste gate valve in a region between the turbine housing and the catalyst. A receiving portion is provided inside the peripheral wall portion of the exhaust passage where the exhaust gas discharged from the bypass passage directly collides.

  In this configuration, the exhaust gas discharged from the bypass passage directly collides with the receiving portion, and a part of the heat of the exhaust gas is transmitted to and accumulated in the receiving portion. The heat of the exhaust gas that has been discharged becomes difficult to be released to the atmosphere from the peripheral wall portion of the exhaust passage.

  As a result, the exhaust gas discharged from the bypass passage can be introduced into the catalyst while maintaining a high temperature. The heat transferred to and accumulated in the receiving portion due to the collision of the exhaust gas is led to the catalyst together with the exhaust gas discharged one after another. Therefore, for example, after the engine is cold started, the catalyst can be heated up relatively quickly to be activated.

  Preferably, the receiving portion may guide the exhaust gas colliding with the receiving portion to flow toward the inlet side of the catalyst.

  In this configuration, the heat of the exhaust gas is less likely to be taken away by the peripheral wall portion of the exhaust passage, which is further advantageous in introducing the exhaust gas into the catalyst while maintaining the high temperature.

  Preferably, a heat insulating member is provided in a region located outside the receiving portion in the peripheral wall portion of the exhaust passage.

  In this case, since the heat insulating member is provided on the peripheral wall portion of the exhaust passage, the heat received by the receiving portion is prevented from being released to the atmosphere through the peripheral wall portion of the exhaust passage. As a result, the heat of the exhaust gas can be efficiently introduced into the catalyst.

  Preferably, a region between the turbine housing and the catalyst in the exhaust passage is shaped so as to go straight in the discharge direction of the exhaust gas discharged from the turbine housing and then bend 90 degrees. The portion has a cone shape that gradually expands toward the catalyst, the exhaust gas discharge direction from the bypass passage is directed to the cone portion, and the receiving portion is provided in the cone portion.

  An exhaust system for an engine according to the present invention includes a bypass passage in which a turbine housing and a catalyst of a supercharger are installed in series in an exhaust gas flow direction in the middle of an exhaust passage of the engine and bypass the turbine wheel of the supercharger. In the configuration in which the discharge port is opened and closed by the waste gate valve, the exhaust gas discharged from the bypass passage can be introduced into the catalyst while being kept at a high temperature.

It is a figure showing the schematic structure of one embodiment of the exhaust system of the engine concerning the present invention. FIG. 2 is an enlarged view of a region between a turbine housing and a catalyst in FIG. 1, showing a state where a waste gate valve is opened. It is the figure which looked at the turbine housing of FIG. 2 from the A direction of FIG. It is a figure which shows the state which closed the waste gate valve | bulb in FIG. FIG. 5 is a view corresponding to FIG. 4 in another embodiment of the engine exhaust device according to the present invention.

  BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the accompanying drawings.

  1 to 4 show an embodiment of the present invention. The engine 1 exemplified in this embodiment is, for example, an in-line four cylinder. An intake manifold 2 for distributing and supplying intake air to each cylinder, and an exhaust manifold 3 for collecting exhaust gas discharged from each cylinder are attached to a cylinder head (not shown) of the engine 1. It has been.

  An intake pipe 4 for taking in air from the atmosphere is connected to the intake manifold 2. An air cleaner 6 is attached to the inlet of the intake pipe 4. The intake manifold 2 and the intake pipe 4 constitute an intake passage.

  A throttle valve 7 for adjusting the intake air amount of the engine 1 is provided upstream of the intake manifold 2 in the intake flow direction. Although not shown, the throttle valve 7 is operated by a throttle motor and an electronic control unit (ECU).

  On the other hand, an exhaust pipe 5 for discharging exhaust gas to the atmosphere is connected to the exhaust manifold 3. The exhaust manifold 3 and the exhaust pipe 5 constitute a part of the exhaust passage. The exhaust pipe 5 is a part called an “elbow”, and goes straight from the exhaust direction of the exhaust gas exhausted from the exhaust port 26 of the turbine housing 24 described below, and then bends approximately 90 degrees to substantially downward in the vertical direction. It is formed in an inverted L shape that extends.

  A catalyst 9 for purifying exhaust gas is provided on the downward portion of the exhaust pipe 5. Since the diameter of the catalyst 9 is set to be larger than the diameter of the downward portion of the exhaust pipe 5, the downward portion of the exhaust pipe 5 has a cone shape that gradually expands toward the catalyst 9. Reference numeral 51 (see FIG. 2) is attached to the cone portion.

  The engine 1 of this embodiment is equipped with a turbocharger 20 as a supercharger. The turbocharger 20 supercharges intake air using exhaust pressure and supplies it to the engine 1, and includes a turbine wheel 21, a compressor impeller 22, and the like.

  The turbine wheel 21 is provided in a turbine housing 24 installed between the exhaust manifold 3 and the exhaust pipe 5 (in the middle of the exhaust passage). The compressor impeller 22 is provided in a compressor housing 25 installed in the middle of the intake pipe 4. The compressor impeller 22 is attached to a turbine shaft 23 that is integral with the turbine wheel 21. Thereby, the turbine wheel 21 and the compressor impeller 22 rotate integrally.

  As an operation of the turbocharger 20, the turbine wheel 21 is rotated by the energy of the exhaust gas discharged from the engine 1, and the compressor impeller 22 is rotated integrally with the turbine wheel 21, so that the air sucked into the intake pipe 4 is The engine is supercharged and is forcibly sent to the combustion chamber of each cylinder of the engine 1. The air supercharged by the compressor impeller 22 is cooled by the intercooler 8. The intercooler 8 is installed in the intake pipe 4 on the downstream side of the compressor impeller 22 in the intake flow direction.

  The turbocharger 20 of this embodiment is provided with a bypass passage 31, a waste gate valve (WGV) 32, and the like.

  The bypass passage 31 is provided in the turbine housing 24 so that the exhaust gas discharged from the engine 1 is guided to the catalyst 9 by bypassing the turbine wheel 21. That is, the bypass passage 31 is installed so as to short-circuit the inlet side and the outlet side of the turbine housing 24. As shown in FIGS. 2 and 3, the exhaust port of the bypass passage 31 is provided next to the exhaust gas exhaust port 26 that rotationally drives the turbine wheel 21 in the turbine housing 24.

  The waste gate valve 32 is installed on the discharge port side of the bypass passage 31 so as to be openable and closable, and adjusts the opening degree of the bypass passage 31 to adjust the exhaust gas bypass amount. By adjusting the exhaust gas bypass amount, for example, the supercharging pressure can be controlled, and the catalyst 9 can be quickly activated when the engine 1 is cold-started.

  The waste gate valve 32 is formed, for example, in a circular shape, and a predetermined outer peripheral position thereof is attached to the support shaft 33 so as to rotate together. Although not shown in the figure, a drive source is connected to the support shaft 33 via a power transmission mechanism, and the drive force generated by the drive source is converted into rotational power for rotating the support shaft 33 by the power transmission mechanism. Then, by transmitting the rotational power to the support shaft 33, the waste gate valve 32 integrally rotated with the support shaft 33 is opened and closed.

  The waste gate valve 32, the support shaft 33, the power transmission mechanism, and the drive source constitute a waste gate valve unit. The drive source can be, for example, a motor, a vacuum regulating valve, or the like. The power transmission mechanism can be, for example, a link mechanism or a gear mechanism.

  As shown in FIGS. 2 to 4, a receiving portion 35 for exhaust gas discharged from the bypass passage 31 is provided in a region between the turbine housing 24 and the catalyst 9 in the exhaust pipe 5.

  The receiving portion 35 is disposed at a position where exhaust gas discharged from the bypass passage 31 directly collides. Specifically, the receiving portion 35 is disposed on an extension line in the discharge direction of the exhaust gas discharged from the bypass passage 27. In this embodiment, the exhaust gas discharged from the bypass passage 27 is set so as to flow straight in the discharge direction as indicated by the thick line in FIG. 2, so that the receiving portion 35 has the linear exhaust gas. It is arranged at the position that hits the flow of. Further, the receiving portion 35 is installed in a state in which exhaust gas colliding with the receiving portion 35 is guided so as to flow toward the inlet side of the catalyst 9.

  As shown in FIGS. 2 and 4, an A / F sensor 10 is provided downstream of the receiving portion 35 in the exhaust gas flow direction. The A / F sensor 10 is installed such that the exhaust gas colliding with the receiving portion 35 hits the tip portion (element arrangement portion).

  Specifically, the exhaust gas discharged from the bypass passage 31 is directed to the outer corner portion of the minimum diameter portion of the cone portion 51 of the exhaust pipe 5. In this embodiment, the receiving portion 35 is formed in a plate shape separately from the exhaust pipe 5, and protrudes toward the catalyst 9 at the outer corner of the minimum diameter portion of the cone portion 51 in the exhaust pipe 5. It is attached. The material of the receiving portion 35 can be a generally known appropriate heat resistant metal or ceramic.

  Further, a heat insulating member 36 is provided in a region located outside the receiving portion 35 in the peripheral wall portion of the exhaust pipe 5 (in this embodiment, the outer surface of the curved portion protruding toward the outside of the exhaust pipe 5). The heat insulating member 36 is formed in a sheet shape, for example, and is attached to the region. The material of the heat insulating member 36 can be a generally known appropriate heat insulating material.

  In the embodiment having such a configuration, the following operations and effects can be obtained.

  First, when the waste gate valve 32 is opened, as shown in FIG. 2, for example, the exhaust gas discharged from the bypass passage 31 directly collides with the receiving portion 35, and the heat of the exhaust gas is reduced. Since the portion is transmitted and accumulated in the receiving portion 35, the heat of the exhaust gas discharged from the bypass passage 31 is not easily released from the peripheral wall portion of the exhaust pipe 5 to the atmosphere. As a result, the exhaust gas discharged from the bypass passage 31 can be introduced into the catalyst 9 while being kept at a high temperature. In addition, the heat transferred to and accumulated in the receiving portion 35 due to the collision of the exhaust gas is led to the catalyst 9 together with the exhaust gas discharged one after another. Therefore, for example, after the engine 1 is cold-started, the catalyst 9 can be heated up and activated relatively quickly.

  In particular, the receiving portion 35 of this embodiment is installed in a state in which exhaust gas colliding with it is guided so as to flow toward the inlet side of the catalyst 9, so that the bypass passage is provided by not including the receiving portion 35, for example. Compared with the case where the exhaust gas discharged from 31 directly collides with the peripheral wall portion of the exhaust pipe 5, the heat of the exhaust gas discharged from the bypass passage 31 is less likely to be taken by the peripheral wall portion of the exhaust pipe 5. As a result, the exhaust gas discharged from the bypass passage 31 is further advantageous in introducing it into the catalyst 9 while maintaining a high temperature.

  Further, in this embodiment, the heat accumulated in the receiving portion 35 is transferred from the peripheral wall portion of the exhaust pipe 5 to the atmosphere by the heat insulating member 36 installed in the region located outside the receiving portion 35 in the peripheral wall portion of the exhaust pipe 5. It can be prevented from being released into the water. Therefore, it is more advantageous when introducing the exhaust gas into the catalyst 9 while keeping the exhaust gas at a high temperature.

  When the waste gate valve 32 is closed, for example, as shown in FIG. 4, all exhaust gas discharged from the engine 1 is introduced toward the turbine wheel 21. Is exhausted from the exhaust port 26 of the turbine housing 24 to the exhaust pipe 5. At this time, the exhaust gas is guided by the inner surface of the exhaust pipe 5 and the receiving portion 35 and introduced into the catalyst 9.

  As described above, in the embodiment to which the present invention is applied, it is possible to prevent the exhaust gas discharged from the bypass passage 31 from being lowered in temperature and introduce it into the catalyst 9 while keeping it as high as possible. Therefore, the catalyst 9 can be activated early. In addition, since a relatively simple configuration that only provides the receiving portion 35 and the heat insulating member 36 is sufficient, the facility cost can be kept as low as possible.

  In addition, this invention is not limited only to the said embodiment, It can change suitably in the range equivalent to the claim and the said range.

  (1) The engine 1 to which the exhaust device described in the above embodiment is applied may be either a diesel engine or a gasoline engine. In the case of a diesel engine, the catalyst 9 is, for example, a diesel particulate filter (DPF), and in the case of a gasoline engine, the catalyst 9 is, for example, a three-way catalyst.

  (2) In the above embodiment, an example in which the heat insulating member 36 is provided in the exhaust pipe 5 is given. However, the present invention is not limited to this, and a configuration in which the heat insulating member 36 is omitted is also included in the present invention. included.

  (3) FIG. 5 shows another embodiment of the present invention. In this embodiment, the installation position of the receiving portion 35 is set so that the exhaust gas discharged from the bypass passage 31 collides with the inner corner portion of the minimum diameter portion in the cone portion 51 of the exhaust pipe 5. It is set.

  Specifically, the receiving portion 35 is attached to the position where the exhaust gas discharged from the bypass passage 31 collides, that is, the inner corner portion of the minimum diameter portion in the cone portion 51 of the exhaust pipe 5, and the free end thereof is The cone portion 51 protrudes obliquely downward in the lateral direction toward the outer corner portion of the smallest diameter portion.

  In this case, since the exhaust gas discharged from the bypass passage 31 directly collides with the receiving portion 35, a part of the heat of the exhaust gas is transmitted to and accumulated in the receiving portion 35. The heat of the exhaust gas discharged from the bypass passage 31 becomes difficult to be released from the peripheral wall portion of the exhaust pipe 5 to the atmosphere. The heat transmitted to the receiving portion 35 is guided to the catalyst 9 together with exhaust gas exhausted one after another. As a result, for example, after the engine 1 is cold started, the catalyst 9 can be heated up and activated relatively quickly.

  Moreover, the receiving portion 35 guides the exhaust gas colliding with the receiving portion 35 so as to flow from the center side of the cone portion 51 toward the inlet side of the catalyst 9. For this reason, the heat of the exhaust gas discharged from the bypass passage 31 is less likely to be taken away by the peripheral wall portion of the exhaust pipe 5, so that the exhaust gas discharged from the bypass passage 31 is further introduced into the catalyst 9 while being kept at a high temperature. Become advantageous.

  According to the present invention, a turbocharger turbine housing and a catalyst are installed in series in the exhaust gas flow direction in the middle of an exhaust passage of an engine, and a discharge port of a bypass passage that bypasses the turbine housing is opened and closed by a waste gate valve. It can be suitably used for the exhaust device having the configuration.

1 engine
2 Intake manifold
3 Exhaust manifold (part of exhaust passage)
4 Intake pipe
5 Exhaust pipe (part of exhaust passage)
DESCRIPTION OF SYMBOLS 51 Cone part 20 Turbocharger 21 Turbine wheel 22 Compressor impeller 24 Turbine housing 26 Discharge port 31 Bypass passage 32 Wastegate valve 33 Support shaft 35 Receiving part 36 Thermal insulation member

Claims (4)

A turbocharger turbine housing and a catalyst are provided in series in the exhaust gas flow direction in the middle of the exhaust passage of the engine.
A bypass passage for bypassing the turbine wheel of the supercharger is provided in the exhaust passage, and a waste gate valve for adjusting a bypass amount of the exhaust gas is provided at an exhaust port of the bypass passage,
In the exhaust passage, in a region between the turbine housing and the catalyst, a receiving portion is provided inside the peripheral wall portion of the exhaust passage so that exhaust gas discharged from the bypass passage directly collides with the exhaust passage. The engine exhaust system. The engine exhaust system according to claim 1,
The engine exhaust device according to claim 1, wherein the receiving portion guides exhaust gas colliding with the receiving portion to flow toward an inlet side of the catalyst. The exhaust system for an engine according to claim 1 or 2,
An exhaust system for an engine, characterized in that a heat insulating member is provided in a region located outside the receiving portion in the peripheral wall portion of the exhaust passage. The engine exhaust system according to any one of claims 1 to 3,
The region between the turbine housing and the catalyst in the exhaust passage is shaped so as to go straight in the exhaust direction of the exhaust gas exhausted from the turbine housing and then bend 90 degrees. The engine has a cone shape that gradually expands toward the catalyst, the exhaust gas discharge direction from the bypass passage is directed to the cone portion, and the receiving portion is provided in the cone portion. Exhaust system.

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