JP4655662B2 - Exhaust gas purification device for internal combustion engine - Google Patents

Description

  The present invention relates to an exhaust emission control device for an internal combustion engine.

  Diesel engines are economical, but it is important to remove particulate matter (particulate matter: hereinafter referred to as “PM” unless otherwise specified), which is suspended particulate matter contained in exhaust gas. It has become a challenge. For this reason, a technique of providing a particulate filter (hereinafter simply referred to as “filter”) for collecting PM in an exhaust system of a diesel engine so that PM is not released into the atmosphere is well known.

  This filter can prevent PM in the exhaust gas from being collected once and released into the atmosphere. However, PM trapped in the filter may accumulate on the filter and cause clogging of the filter. If this clogging occurs, the pressure of the exhaust gas upstream of the filter may increase, leading to a decrease in the output of the internal combustion engine and damage to the filter. In such a case, the PM deposited on the filter can be removed by igniting and burning. The removal of PM deposited on the filter in this way is called filter regeneration.

  However, in order to ignite and burn the PM collected by the filter, it is necessary to raise the temperature of the filter. However, since the exhaust temperature of a diesel engine is usually lower than this temperature, the PM is burned and removed. Was difficult.

In contrast, an oxidation catalyst and a passage for bypassing the oxidation catalyst are provided upstream of the filter, and when the regeneration of the filter is started, the reducing agent is allowed to flow into the bypass passage, and then the reducing agent is caused to flow into the oxidation catalyst to regenerate the filter. A technique of promptly performing is known (for example, refer to Patent Document 1).
JP 2003-166417 A JP 2002-188432 A JP 2004-176571 A JP-A-8-31820

  However, when the reducing agent bypassing the oxidation catalyst flows into the filter, the particulate matter is oxidized from the upstream side in the filter, so that the temperature of the filter and the exhaust rises from the upstream side, and the heat further increases the downstream side. Temperature rises. Therefore, the downstream side becomes very high temperature, and the filter may be overheated at the downstream end.

  The present invention has been made in view of the above problems, and in an exhaust gas purification apparatus for an internal combustion engine, regeneration of a filter can be completed quickly while suppressing an excessive temperature rise during filter regeneration. The purpose is to provide technology.

In order to achieve the above object, an exhaust gas purification apparatus for an internal combustion engine according to the present invention employs the following means. That is,
A particulate filter provided in an exhaust passage of the internal combustion engine and carrying a catalyst having an oxidizing ability on the downstream side;
Reducing agent supply means for supplying a reducing agent to the particulate filter from upstream of the particulate filter;
High-temperature exhaust gas supply means for supplying high-temperature exhaust gas that oxidizes particulate matter to the particulate filter from upstream of the particulate filter;
With
When removing the particulate matter collected by the particulate filter, the reducing agent supply means supplies a reducing agent to the particulate filter, and then the high temperature exhaust supply means supplies the particulate filter to a high temperature. The exhaust gas is supplied.

  In this way, by supporting a catalyst having oxidation ability on the downstream side in the particulate filter, when the reducing agent is supplied to the particulate filter, only the downstream side on which the catalyst is supported rises in temperature. In addition, since heat is generated on the downstream side, the temperature rise on the upstream side of the particulate filter is suppressed. Then, the particulate matter collected mainly in the downstream side in the particulate filter is oxidized and removed.

  Thereafter, high temperature exhaust gas is supplied to the particulate filter in order to oxidize and remove particulate matter collected mainly in the upstream side in the particulate filter. Thereby, the particulate matter collected on the upstream side is oxidized and removed. Even if the heat generated at this time is transmitted to the downstream side in the particulate filter, the particulate matter already collected on the downstream side is removed at this time, so the temperature further increases on the downstream side. Since there is almost nothing, overheating on the downstream side is suppressed.

  In addition, since the temperature rise of the particulate filter is small compared to the case where the temperature of the entire particulate filter is raised to regenerate the particulate filter, even if the upstream and downstream temperatures are increased accordingly, the particulate filter The overheating of the curate filter can be suppressed. And by raising the temperature of the upstream and downstream sides of the particulate filter, the particulate matter is oxidized quickly, and the time required for regeneration of the particulate filter can be shortened.

In the present invention, an oxidation catalyst which is a catalyst having an oxidation capability provided upstream of the particulate filter,
A bypass passage for bypassing the oxidation catalyst;
Further comprising
When the particulate matter trapped in the particulate filter is removed and when the reducing agent is supplied to the particulate filter by the reducing agent supply means, the reducing agent is caused to flow through the bypass passage, and the particulate filter When supplying high-temperature exhaust gas, a reducing agent can be passed through the oxidation catalyst.

  That is, exhaust gas containing a reducing agent is supplied to the particulate filter by flowing the reducing agent through the bypass passage. In the particulate filter, the fuel in the exhaust gas is oxidized on the downstream side where the catalyst is supported, and the particulate matter collected on the downstream side can be oxidized and removed. At this time, since the particulate matter collected on the upstream side is hardly oxidized, overheating of the particulate filter can be suppressed.

  Further, when the reducing agent is allowed to flow through the oxidation catalyst, the reducing agent is oxidized in the oxidation catalyst, so that the temperature of the exhaust gas rises. The particulate matter collected on the upstream side of the particulate filter can be oxidized and removed by flowing this high-temperature exhaust gas through the particulate filter. At this time, since there is almost no particulate matter on the downstream side, the temperature hardly increases further on the downstream side. Therefore, overheating of the particulate filter is suppressed.

In the present invention, it further comprises an oxidation catalyst which is a catalyst having an oxidation ability provided upstream from the particulate filter,
When removing the particulate matter trapped in the particulate filter and when supplying the reducing agent to the particulate filter by the reducing agent supply means, it is downstream of the oxidation catalyst and from the particulate filter. In addition, when the reducing agent is supplied from the upstream side and the high-temperature exhaust gas is supplied to the particulate filter, the reducing agent can be supplied from the upstream side of the oxidation catalyst.

  That is, by supplying the reducing agent downstream from the oxidation catalyst and upstream from the particulate filter, the reducing agent can be supplied to the particulate filter, and the reducing agent and particles can be supplied downstream from the particulate filter. The particulate matter (PM) can be oxidized.

  Moreover, since the reducing agent flows into the oxidation catalyst by supplying the reducing agent from the upstream side of the oxidation catalyst, the reducing agent is oxidized by the oxidation catalyst and the temperature of the exhaust gas is raised. Thereby, high temperature exhaust gas can be supplied to the particulate filter. At this time, since the reducing agent is hardly contained in the exhaust gas, the reducing agent hardly reacts on the downstream side of the particulate filter, and PM does not accumulate on the downstream side. Therefore, the downstream side of the particulate filter Temperature rise can be suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, regeneration of a filter can be completed rapidly, suppressing the excessive temperature rise at the time of filter reproduction | regeneration in the exhaust gas purification apparatus of an internal combustion engine.

  Hereinafter, specific embodiments of an exhaust emission control device for an internal combustion 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 1 to which an exhaust gas purification apparatus for an internal combustion engine according to this embodiment is applied and an exhaust system thereof.

  An exhaust passage 2 leading to the combustion chamber of the internal combustion engine 1 is connected to the internal combustion engine 1. This exhaust passage 2 communicates with the atmosphere downstream.

  In the middle of the exhaust passage 2, an oxidation catalyst 3 and a particulate filter 4 are provided in order from the internal combustion engine 1 side.

  When the oxygen concentration of the inflowing exhaust gas is high, downstream of the center in the particulate filter 4 (hereinafter referred to as the filter 4), the NOx in the exhaust gas is occluded, and the oxygen concentration of the inflowing exhaust gas is reduced. When a reducing agent is present, it supports an NOx storage reduction catalyst (hereinafter referred to as NOx catalyst) having a function of reducing the stored NOx. In the present embodiment, a portion on the downstream side in the filter 4 that carries the NOx catalyst is referred to as a catalyst carrying portion 42, and a portion that does not carry the NOx catalyst on the upstream side of the portion is referred to as a catalyst non-loading portion. 41. For example, the NOx catalyst can be supported only on the downstream side of the filter 4 by immersing only the catalyst support portion 42 in the catalyst solution when the filter 4 is manufactured.

The oxidation catalyst 3 may be any catalyst having an oxidation ability, and may be another type of catalyst such as a three-way catalyst or a NOx catalyst. The catalyst 4 may be supported on the filter 4 as long as it has an oxidizing ability, and may be, for example, an oxidation catalyst or a three-way catalyst.

  Further, a bypass passage 5 that connects an exhaust passage downstream of the internal combustion engine 1 and upstream of the oxidation catalyst 3 and an exhaust passage downstream of the oxidation catalyst 3 and upstream of the filter 4 is provided. . A switching valve 6 that distributes exhaust gas from the internal combustion engine 1 to the oxidation catalyst 3 and the bypass passage 5 is located in the middle of the exhaust passage 2 upstream of the oxidation catalyst 3 and to which the bypass passage 5 is connected. Is provided.

  Further, a fuel addition valve 7 for injecting fuel (light oil) as a reducing agent into the exhaust passage 2 is attached to the exhaust passage 2 upstream of the switching valve 6.

  The internal combustion engine 1 configured as described above is provided with an ECU 8 that is an electronic control unit for controlling the internal combustion engine 1. The ECU 8 is a unit that controls the operation state of the internal combustion engine 1 in accordance with the operation conditions of the internal combustion engine 1 and the request of the driver.

  The switching valve 6 and the fuel addition valve 7 are connected to the ECU 8 via electric wiring, and these are controlled by the ECU 8.

  In this embodiment, when the filter 4 is regenerated, the switching valve 6 is first operated so that all the exhaust flows through the bypass passage 5, and in this state, fuel flows from the fuel addition valve 7 into the exhaust passage 2. Added. The fuel added into the exhaust passage 2 flows through the bypass passage 5 together with the exhaust gas and reaches the filter 4. Since the fuel added from the fuel addition valve 7 into the exhaust gas does not pass through the oxidation catalyst 3, it is hardly oxidized. When the exhaust gas containing the fuel flows into the filter 4, it first passes through the catalyst non-supporting portion 41. However, since the catalyst is not supported on the catalyst non-supporting portion 41, the fuel is hardly oxidized. And flows into the catalyst carrier 42. When the exhaust gas containing a large amount of fuel passes through the catalyst carrier 42, the fuel contained in the exhaust gas is oxidized by the action of the NOx catalyst. For this reason, the temperature of the catalyst carrier 42 rises, so that the PM collected by the catalyst carrier 42 is oxidized.

  In this way, the PM collected on the catalyst carrier 42 is first removed. At this time, since the catalyst non-supporting portion 41 is located on the upstream side of the catalyst supporting portion 42, heat generated in the catalyst supporting portion 42 is difficult to be transmitted to the catalyst non-supporting portion 41. The temperature does not rise very much.

  Then, after the PM trapped in the catalyst carrier 42 is removed, the switching valve 6 is operated so that all the exhaust gas flows through the oxidation catalyst 3, and in this state, fuel flows from the fuel addition valve 7 into the exhaust passage 2. Added. For example, when the differential pressure between the upstream side and the downstream side of the filter 4 is detected and the differential pressure becomes smaller than a predetermined value, it can be determined that PM has been removed from the catalyst support 42. . Alternatively, it may be determined that the PM is removed from the catalyst carrier 42 when the fuel addition time from the fuel addition valve 7 is equal to or longer than a predetermined time.

  The fuel added from the fuel addition valve 7 into the exhaust passage 2 flows into the oxidation catalyst 3 together with the exhaust. In the oxidation catalyst 3, the fuel is oxidized by the action of the catalyst and heat is generated, so that the temperature of the exhaust gas rises in the oxidation catalyst 3. Therefore, the temperature of the exhaust gas flowing out from the oxidation catalyst 3 is high. When the high-temperature exhaust gas flows into the filter 4 and the high-temperature exhaust gas passes through the catalyst non-supporting portion 41, the PM collected in the catalyst non-supporting portion 41 is oxidized and removed.

At this time, the temperature of the exhaust gas further rises, but the temperature rise at this time is only the amount of PM collected by the catalyst non-supporting portion 41. Even if the exhaust gas flows into the catalyst carrier 42, PM collected by the catalyst carrier 42 is removed, and the fuel contained in the exhaust is also oxidized by the oxidation catalyst 3. Since it is oxidized, the temperature of the exhaust gas hardly rises in the catalyst support portion 42. Therefore, the filter 4 is prevented from overheating in the catalyst carrier 42.

  In this way, in this embodiment, it is possible to suppress an excessive increase in the temperature of the filter 4 when the filter 4 is regenerated.

  In addition, since half of the total amount of PM is separately oxidized in the catalyst non-supporting portion 41 or the catalyst supporting portion 42, the amount of heat generated at each location is smaller than that in the past. Therefore, since the maximum temperature of the filter 4 at each location can be made higher than before, PM can be oxidized quickly. That is, when the catalyst is supported on the entire filter as in the prior art, PM collected in the filter 4 during the regeneration of the filter 4 may be oxidized at a time and the filter may be overheated. Therefore, the amount of fuel added is adjusted to be small so that the filter 4 is not overheated, and the filter 4 may be regenerated over time.

  On the other hand, in the present embodiment, the amount of PM oxidized at one time is almost half that of the prior art, so the temperature at the downstream end of the filter 4 at that time is lower than that of the prior art. Therefore, there is a surplus before the filter 4 is overheated, and the fuel addition amount can be increased as compared with the conventional case. Therefore, since the filter 4 can be regenerated at a higher temperature, the regeneration time of the filter 4 can be shortened and fuel consumption can be improved.

  In the present embodiment, when the target for PM removal is changed from the catalyst carrying part 42 to the catalyst non-carrying part 41, the flow of exhaust gas is immediately switched from the bypass passage 5 to the oxidation catalyst 3. Instead, the distribution of the exhaust flow may be gradually switched. That is, at first, all or most of the exhaust gas may be allowed to flow to the bypass passage 5, and the amount of exhaust gas flowing to the oxidation catalyst 3 may be gradually increased as PM removal at the catalyst carrier 42 proceeds. The switching valve 6 can be controlled based on, for example, the differential pressure between the upstream side and the downstream side of the filter 4 or the elapsed time from the start of regeneration of the filter 4. The relationship between the amount of PM trapped in the catalyst carrier 42 and the distribution ratio of exhaust gas by the switching valve 6 may be obtained in advance through experiments or the like and mapped.

  Further, in this embodiment, the catalyst non-supporting portion 41 and the catalyst supporting portion 42 are separated from each other at the center of the filter 4, but they are not necessarily separated at the center and are not clearly separated. Also good. That is, the amount of NOx catalyst supported may be gradually increased from the upstream side to the downstream side of the filter 4.

  FIG. 2 is a diagram showing a schematic configuration of the internal combustion engine 1 to which the exhaust gas purification apparatus for an internal combustion engine according to this embodiment is applied and its exhaust system.

  In addition, about the same member as Example 1, the same number is attached | subjected and description is abbreviate | omitted.

  A burner 10 is connected to the exhaust passage 2 downstream of the internal combustion engine 1 and upstream of the filter 4. The burner 10 includes a fuel supply device 11 and an ignition device 12 that supply fuel to the burner 10.

The burner 10 forms an air-fuel mixture while the fuel supply device 11 supplies fuel, and the air-fuel mixture is ignited by an ignition device 12 to burn. Then, high-temperature combustion gas flows into the exhaust passage 2. The burner 10 can raise the temperature of the filter 4 or the catalyst.

  In this embodiment, when the filter 4 is regenerated, fuel is first supplied from the fuel supply device 11 without ignition by the ignition device 12. Then, since no combustion occurs, the fuel flows into the exhaust passage 2. The fuel flowing into the exhaust passage 2 reaches the filter 4 together with the exhaust. When the exhaust gas containing the fuel flows into the filter 4, it first passes through the catalyst non-supporting portion 41. However, since the catalyst is not supported on the catalyst non-supporting portion 41, the fuel is hardly oxidized. And flows into the catalyst carrier 42. When the exhaust gas containing a large amount of fuel passes through the catalyst carrier 42, the fuel contained in the exhaust gas is oxidized by the action of the NOx catalyst. For this reason, the temperature of the catalyst carrier 42 rises, so that the PM collected by the catalyst carrier 42 is oxidized.

  In this way, the PM collected on the catalyst carrier 42 is first removed. At this time, since the catalyst non-supporting portion 41 is located on the upstream side of the catalyst supporting portion 42, heat generated in the catalyst supporting portion 42 is difficult to be transmitted to the catalyst non-supporting portion 41. The temperature does not rise very much.

  Then, after the PM collected in the catalyst carrier 42 is removed, ignition by the ignition device 12 is performed, and the air-fuel mixture is burned in the burner 10. As a result, combustion gas having a high temperature flows from the burner 10 into the exhaust passage 2. Then, when this high-temperature combustion gas flows into the filter 4 together with the exhaust gas and passes through the catalyst non-supporting part 41, the PM collected in the catalyst non-supporting part 41 is oxidized and removed.

  At this time, the temperature of the exhaust gas further rises, but the temperature rise at this time is only the amount of PM collected by the catalyst non-supporting portion 41. Even if the exhaust gas flows into the catalyst carrier 42, the PM collected by the catalyst carrier 42 is removed, so that the temperature of the exhaust gas almost increases in the catalyst carrier 42. do not do. Therefore, the filter 4 is prevented from overheating in the catalyst carrier 42.

  In this way, in this embodiment, it is possible to suppress an excessive increase in the temperature of the filter 4 when the filter 4 is regenerated.

  In addition, since half of the total amount of PM is separately oxidized in the catalyst non-supporting portion 41 or the catalyst supporting portion 42, the amount of heat generated at each location is smaller than that in the past. Therefore, since the maximum temperature of the filter 4 at each location can be made higher than before, PM can be oxidized quickly. That is, in the present embodiment, the amount of PM oxidized at a time is almost half that of the prior art, so the temperature at the downstream end of the filter 4 at that time is lower than that of the prior art. Therefore, there is a surplus before the filter 4 is overheated, and the fuel addition amount can be increased as compared with the conventional case. Therefore, since the filter 4 can be regenerated at a higher temperature, the regeneration time of the filter 4 can be shortened and fuel consumption can be improved.

  In this embodiment, the catalyst non-supporting portion 41 and the catalyst supporting portion 42 are separated from each other at the center of the filter 4, but they are not necessarily separated at the center and are not clearly separated. Also good. That is, the amount of NOx catalyst supported may be gradually increased from the upstream side to the downstream side of the filter 4.

  FIG. 3 is a diagram showing a schematic configuration of the internal combustion engine 1 to which the exhaust gas purification apparatus for an internal combustion engine according to this embodiment is applied and its exhaust system.

  In addition, about the same member as Example 1, the same number is attached | subjected and description is abbreviate | omitted.

  A second fuel addition valve 20 that injects fuel (light oil) as a reducing agent into the exhaust passage 2 is attached to the exhaust passage 2 downstream of the oxidation catalyst 3 and upstream of the filter 4. Similar to the fuel addition valve 7, the second fuel addition valve 20 adds fuel as a reducing agent into the exhaust passage 2 by a signal from the ECU 8.

  In this embodiment, when the filter 4 is regenerated, first, fuel is supplied from the second fuel addition valve 20. At this time, fuel addition from the fuel addition valve 7 is not performed. Then, the fuel added from the second fuel addition valve 20 into the exhaust passage 2 reaches the filter 4 together with the exhaust. When the exhaust gas containing the fuel flows into the filter 4, it first passes through the catalyst non-supporting portion 41. However, since the catalyst is not supported on the catalyst non-supporting portion 41, the fuel is hardly oxidized. And flows into the catalyst carrier 42. When the exhaust gas containing a large amount of fuel passes through the catalyst carrier 42, the fuel contained in the exhaust gas is oxidized by the action of the NOx catalyst. For this reason, the temperature of the catalyst carrier 42 rises, so that the PM collected by the catalyst carrier 42 is oxidized.

  In this way, the PM collected on the catalyst carrier 42 is first removed. At this time, since the catalyst non-supporting portion 41 is located on the upstream side of the catalyst supporting portion 42, heat generated in the catalyst supporting portion 42 is difficult to be transmitted to the catalyst non-supporting portion 41. The temperature does not rise very much.

  Then, after the PM collected in the catalyst carrier 42 is removed, the fuel addition from the second fuel addition valve 20 is stopped and the fuel addition is performed from the fuel addition valve 7.

  The fuel added from the fuel addition valve 7 into the exhaust passage 2 flows into the oxidation catalyst 3 together with the exhaust. In the oxidation catalyst 3, the fuel is oxidized by the action of the catalyst and heat is generated, so that the temperature of the exhaust gas rises in the oxidation catalyst 3. Therefore, the temperature of the exhaust gas flowing out from the oxidation catalyst 3 is high. When the high-temperature exhaust gas flows into the filter 4 and the high-temperature exhaust gas passes through the catalyst non-supporting portion 41, the PM collected in the catalyst non-supporting portion 41 is oxidized and removed.

  At this time, the temperature of the exhaust gas further rises, but the temperature rise at this time is only the amount of PM collected by the catalyst non-supporting portion 41. Even if the exhaust gas flows into the catalyst carrier 42, PM collected by the catalyst carrier 42 is removed, and the fuel contained in the exhaust is also oxidized by the oxidation catalyst 3. Since it is oxidized, the temperature of the exhaust gas hardly rises in the catalyst support portion 42. Therefore, the filter 4 is prevented from overheating in the catalyst carrier 42.

  In this way, in this embodiment, it is possible to suppress an excessive increase in the temperature of the filter 4 when the filter 4 is regenerated.

In addition, since half of the total amount of PM is separately oxidized by the catalyst non-supporting portion 41 or the catalyst supporting portion 42, the amount of heat generated at each location is smaller than in the conventional case. Therefore, since the maximum temperature of the filter 4 at each location can be made higher than before, PM can be oxidized quickly. That is, in the present embodiment, the amount of PM oxidized at a time is almost half that of the prior art, so the temperature at the downstream end of the filter 4 at that time is lower than that of the prior art. Therefore, there is a surplus before the filter 4 is overheated, and the fuel addition amount can be increased as compared with the conventional case. Therefore, since the filter 4 can be regenerated at a higher temperature, the regeneration time of the filter 4 can be shortened and fuel consumption can be improved.

  In this embodiment, when the PM removal target is the catalyst carrying part 42 to the catalyst non-carrying part 41, the member for adding fuel is switched from the second fuel addition valve 20 to the fuel addition valve 7. However, instead of this, the fuel addition amount may be gradually changed. In other words, fuel may be initially added mainly from the second fuel addition valve 20, and the amount of fuel added from the fuel addition valve 7 may be increased as the PM removal at the catalyst carrier 42 proceeds. The amount of fuel addition is performed based on, for example, the differential pressure between the upstream side and the downstream side of the filter 4 or the elapsed time from the start of regeneration of the filter 4.

  Further, in this embodiment, the catalyst non-supporting portion 41 and the catalyst supporting portion 42 are separated from each other at the center of the filter 4, but they are not necessarily separated at the center, and are not clearly separated. Also good. That is, the amount of NOx catalyst supported may be gradually increased from the upstream side to the downstream side of the filter 4.

1 is a diagram illustrating a schematic configuration of an internal combustion engine to which an exhaust gas purification apparatus for an internal combustion engine according to a first embodiment is applied and an exhaust system thereof. It is a figure which shows schematic structure of the internal combustion engine which applies the exhaust gas purification apparatus of the internal combustion engine which concerns on Example 2, and its exhaust system. FIG. 6 is a diagram illustrating a schematic configuration of an internal combustion engine to which an exhaust gas purification apparatus for an internal combustion engine according to a third embodiment is applied and an exhaust system thereof.

Explanation of symbols

1 Internal combustion engine 2 Exhaust passage 3 Oxidation catalyst 4 Particulate filter 5 Bypass passage 6 Switching valve 7 Fuel addition valve 8 ECU
10 Burner 11 Fuel Supply Device 12 Ignition Device 20 Second Fuel Addition Valve 41 Catalyst Non-Supporting Part 42 Catalyst Supporting Part

Claims (3)

A particulate filter provided in an exhaust passage of the internal combustion engine and carrying a catalyst having an oxidizing ability on the downstream side;
Reducing agent supply means for supplying a reducing agent to the particulate filter from upstream of the particulate filter;
High-temperature exhaust gas supply means for supplying high-temperature exhaust gas that oxidizes particulate matter to the particulate filter from upstream of the particulate filter;
With
When removing the particulate matter collected by the particulate filter, the reducing agent is supplied to the particulate filter by the reducing agent supply means, and the particulate matter collected on the downstream side of the particulate filter. An exhaust gas purification apparatus for an internal combustion engine, wherein after the substance is removed , high temperature exhaust gas is supplied to the particulate filter by the high temperature exhaust gas supply means. A particulate filter provided in an exhaust passage of the internal combustion engine and carrying a catalyst having an oxidizing ability on the downstream side;
Reducing agent supply means for supplying a reducing agent to the particulate filter from upstream of the particulate filter;
High-temperature exhaust gas supply means for supplying high-temperature exhaust gas that oxidizes particulate matter to the particulate filter from upstream of the particulate filter;
An oxidation catalyst, which is a catalyst having an oxidation ability provided upstream of the particulate filter;
A bypass passage for bypassing the oxidation catalyst;
With
When removing the particulate matter collected by the particulate filter, the reducing agent supply means supplies a reducing agent to the particulate filter, and then the high temperature exhaust supply means supplies the particulate filter to a high temperature. Supply exhaust,
When removing the particulate matter trapped in the particulate filter and supplying the reducing agent to the particulate filter by the reducing agent supply means, the reducing agent is caused to flow through the bypass passage, and the particulate filter to when supplying the high-temperature exhaust, an exhaust purifying apparatus for an internal combustion engine you characterized by flowing the reducing agent to the oxidation catalyst. A particulate filter provided in an exhaust passage of the internal combustion engine and carrying a catalyst having an oxidizing ability on the downstream side;
Reducing agent supply means for supplying a reducing agent to the particulate filter from upstream of the particulate filter;
High-temperature exhaust gas supply means for supplying high-temperature exhaust gas that oxidizes particulate matter to the particulate filter from upstream of the particulate filter;
An oxidation catalyst which is a catalyst having an oxidation ability provided upstream of the particulate filter ;
With
When removing the particulate matter collected by the particulate filter, the reducing agent supply means supplies a reducing agent to the particulate filter, and then the high temperature exhaust supply means supplies the particulate filter to a high temperature. Supply exhaust,
When removing the particulate matter trapped in the particulate filter and when supplying the reducing agent to the particulate filter by the reducing agent supply means, it is downstream of the oxidation catalyst and from the particulate filter. also supplying a reducing agent from upstream, when supplying the hot exhaust into the particulate filter, exhaust gas purification apparatus for an internal combustion engine you and supplying a reducing agent from upstream of the oxidation catalyst.

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