JP2009264283A - Exhaust emission control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide superior emission control performances while reducing active oxygen usage in an exhaust emission control device for an internal combustion engine capable of eliminating noxious component in exhaust gas by using active oxygen. <P>SOLUTION: This exhaust emission control device for the internal combustion engine is provided with a filter 21 with an NOx catalyst carrying NOx catalyst having function eliminating NOx, an active oxygen supply device 27 including a supply port 23 supplying active oxygen at an upstream side of the filter 21 with the NOx catalyst, an accumulation degree determination means determining degree of accumulation of particulate matter on the filter 21 with the NOx catalyst, and a control means controlling supply of active oxygen by the active oxygen supply device based on determination result of the accumulation degree determination means, in a filter collecting particulate matter contained in exhaust gas of the internal combustion engine 10. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an exhaust gas purification device for an internal combustion engine.

  As an exhaust gas purifying device for an internal combustion engine, there is known a filter with a NOx catalyst in which a NOx catalyst is supported on a filter that collects PM (Particulate Matter) (for example, JP-A-2006-291833). reference). Such a filter with a NOx catalyst is also called a DPNR (Diesel Particulate-NOx Reduction system). According to this filter with a NOx catalyst, PM and NOx can be simultaneously purified with a single device.

  When the amount of PM accumulated in the NOx catalyst-attached filter increases, it becomes difficult for exhaust gas to pass through and the exhaust pressure increases. For this reason, conventionally, a PM regeneration process for removing PM accumulated in a filter with a NOx catalyst is periodically executed. In this PM regeneration process, the temperature of the filter with the NOx catalyst is raised by a method such as addition of exhaust system fuel, and PM is burned and removed. However, this method requires a fuel for increasing the temperature of the filter with the NOx catalyst, so that there is a problem that the fuel consumption tends to deteriorate.

  In addition, in the above conventional technique, as another problem, when the temperature of the filter with the NOx catalyst is low, such as immediately after starting the internal combustion engine or during low speed running, that is, when the catalyst is not sufficiently activated, the NOx is sufficiently reduced. There is a problem that it cannot be purified.

  On the other hand, JP 2005-538295 A discloses a method of removing particulates contained in exhaust gas by administering ozone as an oxidizing auxiliary agent.

JP 2006-291833 A JP 2005-538295 A

  According to the second prior art, by using ozone, PM can be removed without adding exhaust system fuel. However, electric power is required to generate ozone. For this reason, there is a problem that when the amount of ozone used is increased, fuel consumption is deteriorated. There is still room for improvement in this regard.

  The present invention has been made in view of the above points, and in an exhaust gas purification apparatus for an internal combustion engine that can purify harmful components in exhaust gas using active oxygen, while reducing the amount of active oxygen used, It is an object of the present invention to provide an exhaust gas purification device for an internal combustion engine that can obtain excellent purification performance.

In order to achieve the above object, a first invention is an exhaust gas purification apparatus for an internal combustion engine,
A filter with a NOx catalyst in which a NOx catalyst having a function of purifying NOx is supported on a filter that collects particulate matter contained in exhaust gas of an internal combustion engine;
An active oxygen supply device having a supply port for supplying active oxygen to the upstream side of the filter with NOx catalyst;
Accumulation degree determination means for determining the accumulation degree of particulate matter in the filter with NOx catalyst;
Control means for controlling the supply of active oxygen by the active oxygen supply device based on the determination result of the accumulation degree determination means;
It is characterized by providing.

The second invention is the first invention, wherein
Particulate matter removal active oxygen amount calculating means for calculating the amount of active oxygen for oxidizing and removing the particulate matter accumulated in the filter with NOx catalyst;
NOx purification active oxygen amount calculating means for calculating the amount of active oxygen for purifying NOx;
Based on the active oxygen amount calculated by the particulate matter removing active oxygen amount calculating means and the active oxygen amount calculated by the NOx purifying active oxygen amount calculating means, the active oxygen supply by the active oxygen supply device is Supply amount control means for controlling the supply amount;
It is characterized by providing.

The third invention is the first or second invention, wherein
The control means suppresses or stops the supply of active oxygen for oxidizing and removing the particulate matter when it is determined that the accumulation degree of the particulate matter is smaller than a predetermined degree. To do.

According to a fourth invention, in any one of the first to third inventions,
Representative temperature acquisition means for acquiring a representative temperature of the supply port or the filter with the NOx catalyst;
Supply suppression means for suppressing supply of active oxygen by the active oxygen supply device when the representative temperature exceeds a predetermined value;
It is characterized by providing.

According to a fifth invention, in any one of the first to fourth inventions,
The active oxygen supply device supplies ozone as active oxygen.

  According to the first invention, active oxygen can be supplied to the upstream side of the filter with a NOx catalyst. Thereby, even when the filter with the NOx catalyst is at a low temperature, such as immediately after starting the internal combustion engine or during low-speed running, NOx and particulate matter (PM) can be reduced simultaneously. In this case, the oxidation efficiency of PM by active oxygen differs depending on the degree of PM accumulation in the filter with a NOx catalyst. According to the first invention, it is possible to determine the degree of PM accumulation and control the supply of active oxygen based on the determination result. For this reason, according to 1st invention, when the oxidation efficiency of PM is high, oxidation of PM by active oxygen can be performed. Therefore, since active oxygen can be used effectively without waste, the amount of active oxygen used can be reduced, and fuel consumption can be improved.

  According to the second invention, the amount of active oxygen for oxidizing and removing the PM accumulated in the filter with NOx catalyst and the amount of active oxygen for purifying NOx are calculated, and based on these, the active oxygen amount is calculated. The supply amount of oxygen can be controlled. Thereby, since supply of active oxygen can be controlled more appropriately, active oxygen can be used more effectively without waste. In addition, NOx and PM can be more reliably reduced.

  According to the third invention, when it is determined that the accumulation degree of PM is smaller than the predetermined degree, supply of active oxygen for oxidizing and removing PM is suppressed or stopped. When the degree of PM accumulation is small, the oxidation efficiency of PM by active oxygen decreases. According to the third invention, in such a case, the use of active oxygen for the oxidation of PM is avoided, so that the active oxygen can be effectively used as a whole without further waste.

  According to the fourth aspect of the invention, when the temperature of the active oxygen supply port or the filter with the NOx catalyst is high, the supply of active oxygen can be suppressed. When the temperature of the active oxygen supply port or the filter with the NOx catalyst is high, the added active oxygen is easily decomposed, so that the effect of adding active oxygen is difficult to obtain. In such a case, NOx and PM can be sufficiently reduced by a filter with a NOx catalyst without adding active oxygen, so that the necessity for adding active oxygen is small. According to the fourth invention, by suppressing the supply of active oxygen in such a case, it is possible to avoid unnecessary supply of active oxygen, so that the amount of active oxygen used can be further reduced.

  According to 5th invention, the said effect can be exhibited more notably by using ozone as active oxygen.

Embodiment 1 FIG.
[Description of system configuration]
FIG. 1 is a diagram for explaining a system configuration according to the first embodiment of the present invention. As shown in FIG. 1, the system of the present embodiment includes an internal combustion engine 10. In the present embodiment, the internal combustion engine 10 is a four-cylinder compression ignition internal combustion engine (diesel engine) including four cylinders 13. The internal combustion engine 10 of this embodiment includes a turbocharger 19. The intake air compressed by the compressor of the turbocharger 19 flows into each cylinder 13 through the intake manifold 11. Each cylinder 13 is provided with a fuel injector 14 for injecting fuel directly into the cylinder. The high pressure fuel stored in the common rail 18 is supplied to each fuel injector 14. Fuel in a fuel tank (not shown) is pressurized by the supply pump 17 and supplied to the common rail 18. Exhaust gas discharged from each cylinder 13 joins at the exhaust manifold 12 and flows into the turbine of the turbocharger 19. The exhaust gas that has passed through the turbine flows through the exhaust passage 15.

  A filter 21 with a NOx catalyst is installed in the exhaust passage 15. The NOx catalyst-attached filter 21 is obtained by supporting a NOx catalyst on a filter having a function of collecting particulate matter (Particulate Matter) contained in exhaust gas. According to the filter 21 with NOx catalyst, particulate matter (hereinafter referred to as “PM”) and NOx (nitrogen oxide) can be simultaneously reduced. The NOx catalyst-equipped filter 21 is also referred to as DPNR (Diesel Particulate-NOx Reduction system).

  The NOx catalyst-attached filter 21 of this embodiment is of a wall flow type. That is, the NOx catalyst-attached filter 21 has a filter composed of a honeycomb structure made of a porous ceramic such as cordierite. In this honeycomb structure, cells whose upstream ends are sealed and cells whose downstream ends are sealed are alternately arranged. The exhaust gas first flows into a cell whose downstream end is sealed. Then, after passing through a large number of fine holes formed in the walls of those cells and moving to an adjacent cell (that is, a cell whose upstream end is sealed), it exits downstream of the filter 21 with NOx catalyst. . In such a filter 21 with a NOx catalyst, when exhaust gas permeates the walls of each cell, PM is collected in the fine holes.

The NOx catalyst-attached filter 21 of the present embodiment is a filter in which a NOx storage reduction (NSR) catalyst (NSR: NOx Storage Reduction) is supported on the above-described filter. That is, the NOx catalyst-attached filter 21 has a catalyst component in which a noble metal such as platinum Pt and a NOx occlusion material are arranged on the surface of alumina (Al ₂ O ₃ ), for example. Examples of the NOx storage material include at least selected from alkali metals such as potassium K, sodium Na, lithium Li and cesium Cs, alkaline earths such as barium Ba and calcium Ca, and rare earths such as lanthanum La and yttrium Y. One can be used. In the filter 21 with a NOx catalyst of the present embodiment, as shown in FIG. 2, Pt is used as a noble metal and Ba is used as a NOx storage material. In this specification, the term “occlusion” includes all concepts similar to “holding”, “adsorption”, “absorption”, and the like.

  An ozone supply nozzle 22 is installed on the upstream side of the NOx catalyst-attached filter 21. The ozone supply nozzle 22 is provided with a plurality of ozone supply ports 23. An ozone generator 25 is connected to the ozone supply nozzle 22 via an ozone supply passage 24. In the illustrated configuration, the ozone supply nozzle 22 is disposed inside the casing 26 that houses the NOx catalyst-attached filter 21 and on the front side (upstream side) of the NOx catalyst-attached filter 21. In the present embodiment, the ozone generator 25, the ozone supply passage 24, and the ozone supply nozzle 22 constitute an ozone supply device 27.

  As the ozone generator 25, a mode in which ozone is generated while flowing dry air or oxygen as a raw material in a discharge tube to which a high voltage can be applied, or any other type can be used. The dry air or oxygen used as a raw material here is a gas taken from outside the exhaust passage 15, for example, a gas contained in the outside air.

According to the ozone supply device 27 as described above, ozone (O ₃ ) can be generated by the ozone generator 25, and this ozone can be injected from the ozone supply port 23 of the ozone supply nozzle 22. Thereby, ozone can be added into the exhaust gas on the upstream side of the filter 21 with the NOx catalyst.

  A temperature sensor 28 is installed in the exhaust passage 15 in the vicinity of the ozone supply nozzle 22. According to this temperature sensor 28, the temperature near the ozone supply port 23 can be detected. Further, a differential pressure sensor 30 for detecting a differential pressure ΔP between the upstream pressure and the downstream pressure of the NOx catalyst-equipped filter 21 is installed in the exhaust passage 15. As the accumulated amount of PM in the filter with catalyst 21 increases, the pressure loss of the filter with catalyst 21 increases, so the differential pressure ΔP increases. That is, the accumulated amount of PM correlates with the differential pressure ΔP. Accordingly, the PM accumulation amount (accumulation degree) can be determined based on the differential pressure ΔP.

  The system of the present embodiment further includes an ECU (Electronic Control Unit) 50. The ECU 50 controls the internal combustion engine 10 such as the crank angle sensor 46, the air flow meter 47, and the accelerator position sensor 48 in addition to the fuel injector 14, the ozone generator 25, the temperature sensor 28, and the differential pressure sensor 30 described above. Various sensors and actuators are electrically connected.

The storage material of the NOx catalyst-attached filter 21 absorbs NOx by forming nitrate (Ba (NO ₃ ) _{2 in} this embodiment). The storage material can well absorb NO ₂ , NO ₃ or N ₂ O ₅ in NOx. On the other hand, most of NOx originally contained in the exhaust gas is NO (nitrogen monoxide). NO cannot be absorbed by the occlusion material as it is. Therefore, the NOx catalyst with filter 21, by noble metal (platinum Pt in this embodiment) as a catalyst, NO ₂ is produced and NO in exhaust gas and oxygen O ₂ react, absorbing the NO ₂ The material is made to absorb.

However, the activity of the noble metal catalyst does not appear unless the temperature is higher than a certain temperature (for example, 200 ° C. or higher). Therefore, when the temperature of the filter 21 with the NOx catalyst is lower than that temperature, NO is not oxidized to NO ₂ by the noble metal catalyst, and therefore NOx cannot be occluded. Further, in order to sufficiently activate the noble metal catalyst, a higher temperature (for example, about 300 ° C.) is required. For this reason, when the temperature of the NOx catalyst-equipped filter 21 is lower than that temperature, NOx cannot be sufficiently occluded.

  Therefore, in the present embodiment, ozone is supplied by the ozone supply device 27 and ozone is added to the exhaust gas in order to prevent NOx from being released into the atmosphere when the temperature of the filter 21 with the NOx catalyst is low. It was decided. Ozone has a strong oxidizing power. For this reason, NOx and ozone can react in the gas phase from a low temperature of about room temperature.

FIG. 2 is a diagram showing how ozone and NO react and are absorbed by the storage material. When ozone is supplied, NO in the exhaust gas is converted to NO ₂ , NO _3, or N ₂ O ₅ by reacting with ozone. The occlusion material Ba can sufficiently absorb NO ₂ , NO ₃ or N ₂ O ₅ from a low temperature of about room temperature to form nitrate. Therefore, by supplying ozone, the NOx can be absorbed by the storage material even when the filter 21 with the NOx catalyst 21 is at a low temperature. For this reason, according to the present embodiment, even when the temperature of the filter 21 with the NOx catalyst is low, such as immediately after starting the internal combustion engine 10 or during low-speed running, the release of NOx into the atmosphere is sufficiently suppressed. Can do.

  In the present embodiment, when the PM accumulated in the NOx catalyst-attached filter 21 is oxidized (burned) and removed, ozone is supplied by the ozone supply device 27 and the ozone and PM are reacted. . According to ozone having a strong oxidizing power, PM can be reliably oxidized and removed without increasing the temperature of the filter 21 with NOx catalyst.

  However, according to the knowledge of the present inventors, when the amount of PM accumulated in the NOx catalyst-attached filter 21 is small, the PM oxidation efficiency (combustion efficiency) when ozone is supplied tends to be low. The reason is considered as follows. When the amount of accumulated PM is small, the resistance when the exhaust gas permeates the walls of each cell of the NOx catalyst-attached filter 21 is small, so the time required for the exhaust gas to permeate the walls of each cell is shortened. For this reason, the contact time between ozone added to the exhaust gas and the PM accumulated in the wall of each cell is shortened. As a result, it is considered that sufficient time for ozone to react with PM cannot be taken, and the oxidation efficiency of PM decreases. When the oxidation efficiency of PM decreases, more ozone must be supplied when removing PM. If it does so, since the usage-amount of ozone will increase, the electric power consumed for the production | generation of ozone will increase, and the deterioration of a fuel consumption will be caused.

  Therefore, in the present embodiment, when the accumulated amount of PM is small, that is, when the differential pressure ΔP between the upstream and downstream of the NOx catalyst-equipped filter 21 is smaller than a predetermined determination value, supply of ozone for oxidizing PM Decided to stop. Thereby, the fall of the oxidation efficiency of PM can be prevented and the amount of ozone used for removal of PM can be reduced.

Further, in this embodiment, when the temperature near the ozone supply port 23 is a high temperature (300 ° C. or higher in this embodiment) at which ozone is easily decomposed, ozone is supplied. It was decided to stop. In such a case, even if ozone is added, many of them are thermally decomposed, so that it is difficult to obtain an effect of promoting NOx absorption and PM oxidation. Further, when the temperature in the vicinity of the ozone supply port 23 is at such a high temperature, it can be determined that the temperature of the filter 21 with the NOx catalyst is also higher than the temperature at which the noble metal catalyst is sufficiently activated. Thus, NOx can be sufficiently absorbed by the storage material without adding ozone. PM can also be expected to be continuously oxidized by the active oxygen generated in the NOx occlusion reaction and O ₂ contained in the exhaust gas. For this reason, when the temperature near the ozone supply port 23 is high, the necessity for adding ozone is small. In this embodiment, by stopping the supply of ozone in such a case, the amount of ozone used can be reduced, and fuel consumption can be improved.

[Specific Processing in Embodiment 1]
FIG. 3 is a flowchart of a routine executed by the ECU 50 in the present embodiment in order to realize the above function. According to the routine shown in FIG. 3, first, it is determined whether or not the temperature near the ozone supply port 23 detected by the temperature sensor 28 is less than 300 ° C. (step 100).

  If it is determined in step 100 that the temperature near the ozone supply port 23 is less than 300 ° C., then the amount of ozone required to purify (absorb) NOx is calculated (step 102). ). In the present embodiment, the ECU 50 has a map created by examining in advance the relationship between various conditions such as engine speed, engine load, temperature of the filter 21 with NOx catalyst, and the amount of ozone required to purify NOx. Is remembered. In this step 102, the amount of ozone for purifying NOx is calculated based on the map.

  Subsequently, it is determined whether or not the differential pressure ΔP detected by the differential pressure sensor 30 is less than a predetermined determination value α (step 104). If the differential pressure ΔP is greater than or equal to the determination value α in step 104, it can be determined that the efficiency of oxidizing the PM with ozone increases because the amount of accumulated PM in the NOx catalyst-attached filter 21 is large. Therefore, in this case, the amount of ozone necessary to oxidize PM is calculated based on a value such as differential pressure ΔP (step 106).

  On the other hand, when the differential pressure ΔP is less than the determination value α in step 104, it is determined that the efficiency of oxidizing the PM with ozone is low because the PM accumulation amount of the NOx catalyst-attached filter 21 is small. it can. In this case, the amount of ozone for oxidizing the PM is not calculated, and the initial value remains zero.

  Following the processing in step 104 or 106, the ozone supply device 27 is driven to add ozone into the exhaust gas (step 108). In this step 108, when the amount of ozone necessary for oxidizing the PM is calculated in step 106, the amount of ozone necessary for purifying the amount of ozone and the NOx calculated in step 102 is determined. The ozone supply device 27 is controlled so that the total amount of ozone is supplied from the ozone supply port 23. On the other hand, when the amount of ozone for oxidizing PM is not calculated (that is, when the initial value remains zero), only the amount of ozone necessary for purifying the NOx calculated in step 102 is obtained. The ozone supply device 27 is controlled so as to be supplied from the ozone supply port 23.

  On the other hand, if it is determined in step 100 that the temperature near the ozone supply port 23 is 300 ° C. or higher, the ozone supply by the ozone supply device 27 is stopped. In this case, since it can be determined that the temperature of the NOx catalyst-equipped filter 21 is sufficiently high, NOx and PM can be sufficiently purified without supplying ozone. For this reason, by stopping supply of ozone, power consumption can be reduced and fuel consumption can be improved.

  In the present invention, the determination of the ozone supply stop in the step 100 may be made based on the temperature (bed temperature) of the filter 21 with NOx catalyst instead of the temperature near the ozone supply port 23. Further, the method for acquiring the temperature near the ozone supply port 23 and the temperature of the filter 21 with the NOx catalyst is not limited to the method of directly detecting by the temperature sensor, but is estimated based on the engine speed, the engine load, the exhaust temperature, and the like. You may use the method to do. Further, in step 110 described above, the supply of ozone may not be completely stopped, but only the suppression of ozone supply (reduction of supply amount) may be performed.

  According to the routine processing shown in FIG. 3 described above, ozone is added to the exhaust gas even when the temperature of the filter 21 with NOx catalyst is low, such as immediately after starting the internal combustion engine 10 or during low-speed running. Thus, NOx and PM can be reduced simultaneously.

  Further, according to the routine processing shown in FIG. 3, when it is determined that the amount of PM accumulated in the NOx catalyst-attached filter 21 is large, the amount of ozone necessary for purifying NOx and the PM are oxidized. The total amount required for ozone is supplied from the ozone supply port 23. Ozone and NOx react in the gas phase. Therefore, in this case, ozone supplied from the ozone supply port 23 first reacts with NOx. This reaction consumes an amount of ozone necessary to purify NOx, and an amount of ozone necessary to oxidize PM remains. The remaining ozone reacts with the accumulated PM when passing through the walls of the cells of the filter 21 with the NOx catalyst. Therefore, PM can be oxidized and removed.

  When the amount of accumulated PM is large, as described above, the oxidation efficiency of PM by ozone increases, so that PM can be efficiently oxidized by a relatively small amount of ozone. For this reason, the usage-amount of ozone can be saved and the deterioration of a fuel consumption can be suppressed reliably.

  On the other hand, when it is determined that the amount of PM accumulated in the NOx catalyst-attached filter 21 is small, only an amount of ozone necessary for purifying NOx is supplied from the ozone supply port 23. In this case, almost all of the ozone supplied from the ozone supply port 23 is consumed by the reaction with NOx in the gas phase. For this reason, the PM accumulated in the filter 21 with the NOx catalyst remains without being oxidized.

  When the amount of accumulated PM is small, as described above, the oxidation efficiency of PM by ozone is lowered. Therefore, in order to effectively use ozone without waste, it is desirable not to use ozone for oxidation of PM in such a case. According to this embodiment, as described above, when the oxidation efficiency of PM by ozone is low, it is possible to prevent consumption of ozone for the oxidation of PM. For this reason, ozone can be used effectively without waste, and since the amount of ozone used can be reduced as a whole, deterioration of fuel consumption can be reliably suppressed.

  In the present embodiment, when it is determined that the amount of accumulated PM is small, ozone for oxidizing the PM is not supplied. However, in the present invention, the supply is suppressed (the supply amount is reduced). ).

  In the present embodiment, the internal combustion engine 10 is described as being of the compression ignition type, but the present invention is also applicable to a spark ignition type internal combustion engine.

  In this embodiment, the PM accumulation degree of the NOx catalyst-attached filter 21 is determined based on the output of the differential pressure sensor 30, but in the present invention, this determination method is not limited to this. For example, a PM emission amount map from the internal combustion engine 10 may be prepared, and the PM accumulation degree may be determined by integrating the PM emission amount calculated based on the map.

  Further, the ozone supply device 27 of the present embodiment is configured to supply the ozone generated by the ozone generator 25 as it is into the exhaust passage 15, but in the present invention, ozone is generated and stored in advance. The stored ozone may be supplied into the exhaust passage 15 when necessary.

In the present embodiment, ozone is added to the exhaust gas as active oxygen. However, in the present invention, other types of active oxygen (for example, O ⁻ , O ²⁻ , O ₂ ⁻⁾ are used instead of ozone. , O ₃ ⁻ , O _n ^−, etc.) may be added to the exhaust gas.

In the present embodiment, the NOx catalyst supported on the NOx catalyst-attached filter 21 is described as an NOx storage reduction catalyst. However, in the present invention, the NOx catalyst-attached filter 21 is a selective reduction-type NOx catalyst ( It may carry SCR: Selective Catalytic Reduction. As the catalyst component of the selective reduction type NOx catalyst, for example, a catalyst in which Fe is supported on the surface of zeolite can be preferably used. In the case of a selective reduction type NOx catalyst, a reducing agent such as urea is preferably used. In the selective reduction type NOx catalyst, the best purification rate is obtained when the ratio of the amount of NO to the amount of NO ₂ is 1: 1. Therefore, in the case of a selective reduction type NOx catalyst, it is preferable to control the supply amount of active oxygen so that the ratio of the amount of NO in the catalyst to the amount of NO ₂ is 1: 1.

  In the first embodiment described above, the ozone supply device 27 corresponds to the “active oxygen supply device” in the first invention, and the temperature sensor 28 corresponds to the “representative temperature acquisition means” in the fourth invention. Yes. Further, when the ECU 50 executes the processing of step 104, the “accumulation degree determination means” in the first invention performs the processing of steps 106 and 108, thereby the “control means in the first invention. "By executing the processing of step 106, the" particulate matter removing active oxygen amount calculating means "in the second invention performs the processing of step 102, When the “NOx purifying active oxygen amount calculating means” executes the processing of step 108, the “supply amount control means” in the second invention executes the processing of steps 100 and 110, thereby Each of the “supply suppression means” in the present invention is realized.

It is a figure for demonstrating the system configuration | structure of Embodiment 1 of this invention. It is a figure which shows a mode that ozone and NO react and are absorbed by the storage material. It is a flowchart of the routine performed in Embodiment 1 of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Internal combustion engine 11 Intake manifold 12 Exhaust manifold 13 Cylinder 14 Fuel injector 15 Exhaust passage 17 Supply pump 18 Common rail 19 Turbocharger 21 NOx catalyst filter 22 Ozone supply nozzle 23 Ozone supply port 24 Ozone supply passage 25 Ozone generator 26 Casing 27 Ozone Supply device 28 Temperature sensor 30 Differential pressure sensor 50 ECU

Claims (5)

A filter with a NOx catalyst in which a NOx catalyst having a function of purifying NOx is supported on a filter that collects particulate matter contained in exhaust gas of an internal combustion engine;
An active oxygen supply device having a supply port for supplying active oxygen to the upstream side of the filter with NOx catalyst;
Accumulation degree determination means for determining the accumulation degree of particulate matter in the filter with NOx catalyst;
Control means for controlling the supply of active oxygen by the active oxygen supply device based on the determination result of the accumulation degree determination means;
An exhaust gas purifying device for an internal combustion engine, comprising: Particulate matter removal active oxygen amount calculating means for calculating the amount of active oxygen for oxidizing and removing the particulate matter accumulated in the filter with NOx catalyst;
NOx purification active oxygen amount calculating means for calculating the amount of active oxygen for purifying NOx;
Based on the active oxygen amount calculated by the particulate matter removing active oxygen amount calculating means and the active oxygen amount calculated by the NOx purifying active oxygen amount calculating means, the active oxygen supply by the active oxygen supply device is Supply amount control means for controlling the supply amount;
The exhaust gas purifying device for an internal combustion engine according to claim 1, comprising:   The control means suppresses or stops the supply of active oxygen for oxidizing and removing the particulate matter when it is determined that the accumulation degree of the particulate matter is smaller than a predetermined degree. The exhaust gas purifying device for an internal combustion engine according to claim 1 or 2. Representative temperature acquisition means for acquiring a representative temperature of the supply port or the filter with NOx catalyst;
Supply suppression means for suppressing supply of active oxygen by the active oxygen supply device when the representative temperature exceeds a predetermined value;
The exhaust gas purification device for an internal combustion engine according to any one of claims 1 to 3, further comprising:   The exhaust gas purification device for an internal combustion engine according to any one of claims 1 to 4, wherein the active oxygen supply device supplies ozone as active oxygen.

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