JP2003184545A - EXHAUST EMISSIONS CONTROL CATALYST REDUCTION AMOUNT DETECTION METHOD, EXHAUST EMISSIONS CONTROL MANAGEMENT METHOD, AND METHOD AND APPARATUS FOR CALCULATING EXHAUST EMISSIONS CONTROL CATALYST NOx OCCLUSION AMOUNT FOR INTERNAL COMBUSTION ENGINE - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately obtain an NOx reduction amount of a NOx occlusion reducing catalyst for an internal combustion engine. <P>SOLUTION: The NOx reduction amount enoxredrate per unit time is obtained (S226) by calculating a catalyst deterioration ratio esoxratio (S218 to S222) and then obtaining a catalyst transmissivity epassr (S224). Using the NOx reduction amount enoxredrate per unit time obtained highly accurately in the manner described in the foregoing allows the NOx reduction amount to be highly accurately obtained. Since the NOx occlusion amount is also obtained highly accurately, a highly accurate exhaust emissions control management is enabled. As a result, a rich spike timing is appropriately determined, which allows a rich spike of an adequate amount to be performed. This economizes on fuel and eliminates NOx that is otherwise discharged to an outside. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust purification catalyst reduction amount detection method for an internal combustion engine, an exhaust purification management method, an exhaust purification catalyst NOx storage amount calculation method and an apparatus.

[0002]

2. Description of the Related Art As an exhaust gas purification system for an internal combustion engine, NOx in the exhaust gas is stored during execution of stratified charge combustion or lean combustion, and the stoichiometric air-fuel ratio or even higher fuel concentration (rich) is provided.
There is known an exhaust gas purification management system using a NOx storage reduction catalyst that releases the stored NOx and reduces and purifies it when the oxygen concentration in the exhaust gas is reduced by the start of combustion.
00-170527). In such a system, NO
When the NOx storage amount in the x storage reduction catalyst reaches a predetermined amount, a rich spike is executed to supply a high concentration of fuel to the internal combustion engine to discharge a large amount of unburned gas such as HC and CO into the exhaust gas. ing. The unburned gas acts as a reducing agent on the NOx storage reduction catalyst, so that the stored NOx disappears, so that the NOx of the NOx storage reduction catalyst.
The storage capacity can be restored.

[0003]

In such an exhaust gas purification management system, in order to supply a sufficient amount of reducing agent due to rich spikes and to prevent NOx from being emitted to the outside during combustion such as stratified combustion or lean combustion. Must accurately detect the NOx storage amount in the NOx storage reduction catalyst. For this reason, in the prior art, the NOx amount contained in the exhaust gas is calculated according to the operating state of the internal combustion engine, and the NOx storage amount in the NOx storage reduction catalyst is calculated with high accuracy by integrating the NOx amount.

By the way, in order to accurately calculate the NOx storage amount, the NOx reduction amount by the reducing agent also needs to be obtained with high accuracy. However, in the above-mentioned conventional technique, although the accuracy of the NOx storage amount is considered, the NOx reduction amount is not considered to increase the accuracy. Therefore, it cannot be said that exhaust gas purification management is performed with sufficiently high accuracy.

The present invention provides a method and apparatus for detecting an exhaust purification catalyst reduction amount of an internal combustion engine capable of obtaining a NOx reduction amount with high precision, and a highly accurate exhaust purification management by being able to obtain the NOx reduction amount with high precision. An exhaust purification control method and device that can be executed, and an exhaust purification catalyst NOx storage amount calculation method and device that can obtain a NOx storage amount with high precision by being able to obtain a NOx reduction amount with high precision. It is what

[0006]

[Means for Solving the Problems] Means for achieving the above-mentioned objects and their effects will be described below. An exhaust gas purification catalyst reduction amount detection method for an internal combustion engine according to claim 1,
A method for detecting a reduction amount of an exhaust purification catalyst of an internal combustion engine having an NOx storage reduction catalyst in an exhaust system, comprising: a reducing agent amount flowing into the NOx storage reduction catalyst; and a reducing agent permeability in the NOx storage reduction catalyst. Based on the above, the reduction amount in the NOx storage reduction catalyst is detected.

When the reducing agent is passed through the NOx storage reduction catalyst to reduce the NOx in the NOx storage reduction catalyst,
Even if the NOx storage reduction catalyst has a sufficient NOx storage amount, not all of the passing reducing agent is oxidized and contributes to the reducing action. That is, part of the reducing agent is NOx
It is exhausted from the NOx storage reduction catalyst without being completely oxidized inside the storage reduction catalyst. Therefore, if the ratio of the unoxidized portion of the reducing agent, that is, the transmittance is not taken into consideration, highly accurate NOx
No reduction amount can be obtained.

Therefore, in the present invention, the amount of reduction in the NOx storage reduction catalyst is detected in consideration of the above-mentioned transmittance together with the amount of reducing agent. In this way, the NOx reduction amount can be obtained with high accuracy.

According to a second aspect of the present invention, there is provided the exhaust gas purification catalyst reduction amount detection method for an internal combustion engine according to the first aspect, wherein the reducing agent amount flowing into the NOx storage reduction catalyst is included in the exhaust gas discharged from the combustion chamber of the internal combustion engine. It is characterized in that it is detected as the amount of reducing component to be generated.

As described above, since the reducing component contained in the exhaust gas discharged from the combustion chamber can be used as the reducing agent, the reducing component can be detected directly or indirectly by detecting the amount of the reducing component contained in the exhaust gas. The amount can be easily obtained with high accuracy. As a result, the NOx reduction amount can be obtained with high accuracy.

According to a third aspect of the present invention, there is provided an exhaust gas purification catalyst reduction amount detection method for an internal combustion engine according to the second aspect, based on the intake air amount sucked into the internal combustion engine and the air-fuel ratio upstream of the NOx storage reduction catalyst. It is characterized in that the amount of reducing agent that has flowed into the NOx storage reduction catalyst is detected.

As the fuel concentration of the air-fuel ratio upstream of the NOx storage reduction catalyst becomes higher than the stoichiometric air-fuel ratio, the concentration of the reducing component contained in the exhaust gas becomes higher. Further, in this case, as the intake air amount taken into the internal combustion engine increases, the exhaust amount also increases, and the total reducing component amount increases.

Since the reducing component contained in the exhaust gas depends on the intake air amount and the air-fuel ratio upstream of the NOx storage reduction catalyst as described above, the reduction component flowing into the NOx storage reduction catalyst based on the intake air amount and the air-fuel ratio. The amount of agent can be easily detected with high accuracy. As a result, the NOx reduction amount can be obtained with high accuracy.

According to a fourth aspect of the present invention, there is provided an exhaust gas purification catalyst reduction amount detection method for an internal combustion engine, comprising:
The transmittance is detected based on the degree of deterioration of the NOx storage reduction catalyst and the bed temperature of the NOx storage reduction catalyst.

It has been found that the permeability of the reducing agent in the NOx storage reduction catalyst changes according to the degree of deterioration of the NOx storage reduction catalyst and the bed temperature of the NOx storage reduction catalyst. Therefore, the above-described transmittance can be easily and highly accurately obtained based on the degree of deterioration of the NOx storage reduction catalyst and the bed temperature of the NOx storage reduction catalyst. As a result, NOx with high accuracy
The amount of reduction can be calculated.

According to a fifth aspect of the present invention, in the exhaust gas purification catalyst reduction amount detection method for an internal combustion engine, in the fourth aspect, the degree of deterioration of the NOx storage reduction catalyst is detected as a degree of sulfur poisoning of the NOx storage reduction catalyst. It is characterized by

Since the cause of the degree of deterioration of the NOx storage reduction catalyst that affects the above-mentioned transmittance is mainly due to sulfur poisoning, the degree of sulfur poisoning of the NOx storage reduction catalyst is detected to detect the NOx storage reduction catalyst. It can be the degree of deterioration. As a result, an appropriate transmittance can be obtained, and the NOx reduction amount can be obtained with high accuracy.

According to a sixth aspect of the present invention, there is provided an exhaust gas purification catalyst reduction amount detection method for an internal combustion engine, wherein the NO
The deterioration degree of the x storage reduction catalyst is set according to the bed temperature of the NOx storage reduction catalyst.

The degree of deterioration of the NOx occlusion reduction catalyst changes depending on the bed temperature of the NOx occlusion reduction catalyst, and even if the bed temperature changes, the degree of deterioration cannot be determined with high accuracy. Therefore NOx
By setting the degree of deterioration according to the bed temperature of the storage reduction catalyst, an appropriate degree of deterioration can be obtained and the transmittance becomes highly accurate, so that the NOx reduction amount can be obtained with high accuracy.

According to a seventh aspect of the present invention, there is provided an exhaust gas purification catalyst reduction amount detecting method for an internal combustion engine, comprising:
The degree of deterioration of the NOx storage / reduction catalyst is determined based on the unused NOx storage capacity and the current NOx storage capacity of the NOx storage / reduction catalyst.

As described above, the degree of deterioration of the NOx storage-reduction catalyst can be determined with high accuracy based on the NOx storage capacity when the NOx storage-reduction catalyst is not used and the current NOx storage capacity, so that the transmittance is highly accurate. Therefore, the NOx reduction amount can be calculated with high accuracy.

In the exhaust gas purification management method for an internal combustion engine according to claim 8, the reduction amount of the NOx storage reduction catalyst is obtained by the exhaust gas purification catalyst reduction amount detection method for an internal combustion engine according to any one of claims 1 to 7, and It is characterized in that the NOx amount in the exhaust gas is obtained based on the operating state of the engine, and the exhaust gas purification management is executed based on the NOx amount and the reduction amount.

The reduction amount for the NOx storage reduction catalyst and the NOx amount in the exhaust gas are directly related to the NOx storage state in the NOx storage reduction catalyst. Therefore, by using the reduction amount of the NOx storage reduction catalyst obtained as described in any one of claims 1 to 7 as the reduction amount, highly accurate exhaust gas purification management becomes possible.

According to a ninth aspect of the present invention, there is provided an exhaust gas purification control method for an internal combustion engine, wherein the NOx storage reduction catalyst is obtained by the exhaust purification catalyst reduction amount detection method for an internal combustion engine according to any one of the first to seventh aspects. The exhaust gas purification management is executed based on the NOx storage amount of the NOx storage reduction catalyst calculated by the balance calculation of the reduction amount of NOx and the NOx amount in exhaust gas obtained based on the operating state of the internal combustion engine. And

As described above, by using the calculated reduction amount as described in any one of claims 1 to 7 in the balance calculation of the reduction amount and the NOx amount, the NOx storage amount of the NOx storage reduction catalyst can be highly accurately determined. Therefore, highly accurate exhaust gas purification management becomes possible.

A method for calculating an NOx storage amount of an exhaust purification catalyst for an internal combustion engine according to a tenth aspect of the present invention is the NOx storage reduction catalyst for an NOx storage reduction catalyst obtained by the exhaust purification catalyst reduction amount detection method for an internal combustion engine according to any one of the first to seventh aspects. It is characterized in that the NOx storage amount of the NOx storage reduction catalyst is calculated by a balance calculation of the reduction amount and the NOx amount in the exhaust gas obtained based on the operating state of the internal combustion engine.

As described above, by using the reduction amount in the balance calculation, the NOx storage amount of the NOx storage reduction catalyst can be obtained with high accuracy. The exhaust gas purification catalyst reduction amount detection device for an internal combustion engine according to claim 11, wherein the exhaust system is provided with NOx.
An exhaust gas purification catalyst reduction amount detection device for an internal combustion engine, comprising an occlusion reduction catalyst, comprising: an inflow reducing agent amount detection means for detecting an amount of reducing agent flowing into the NOx occlusion reduction catalyst;
The reducing agent permeability detecting means for detecting the reducing agent permeability in the storage reduction catalyst, the reducing agent amount detected by the inflowing reducing agent amount detecting means and the reducing agent permeability detecting means And a reduction amount detecting means for detecting the reduction amount in the NOx storage reduction catalyst based on the transmittance.

As described above, when the reducing agent is passed through the NOx storage / reduction catalyst to reduce the inside of the NOx storage / reduction catalyst, even if the NOx storage / reduction catalyst has a sufficient NOx storage amount, a part of the reducing agent is present. Is exhausted from the NOx storage reduction catalyst without being completely oxidized inside the NOx storage reduction catalyst. Therefore, a highly accurate NOx reduction amount cannot be obtained unless the transmittance, which is the ratio of the unoxidized portion of the reducing agent, is taken into consideration.

Therefore, in the present invention, the reducing agent permeability detecting means detects the permeability of the reducing agent in the NOx storage reduction catalyst. Therefore, the reduction amount detecting means can detect the reduction amount in the NOx storage reduction catalyst with high accuracy by using the transmittance as described above together with the reducing agent amount detected by the inflow reducing agent amount detecting means. it can.

According to a twelfth aspect of the present invention, there is provided the exhaust gas purification catalyst reduction amount detection device for an internal combustion engine according to the eleventh aspect, wherein the inflow reducing agent amount detection means is the reduction component amount contained in the exhaust gas discharged from the combustion chamber of the internal combustion engine. Is detected as the amount of reducing agent that has flowed into the NOx occlusion reduction catalyst.

In the internal combustion engine, since the reducing component contained in the exhaust gas discharged from the combustion chamber serves as a reducing agent, the inflow reducing agent amount detecting means detects the amount of the reducing component contained in the exhaust gas discharged from the combustion chamber. By doing so, the amount of reducing agent that has flowed into the NOx storage reduction catalyst can be easily obtained. As a result, the reduction amount detecting means can obtain the NOx reduction amount with high accuracy.

According to a thirteenth aspect of the present invention, there is provided an exhaust gas purification catalyst reduction amount detection device for an internal combustion engine, wherein the intake air amount detection means for detecting the amount of intake air taken into the internal combustion engine and the NOx storage reduction catalyst upstream side according to the twelfth aspect. And an air-fuel ratio detecting means for detecting an air-fuel ratio from the exhaust gas component of It is characterized in that the amount of reducing agent that has flowed into the reduction catalyst is detected.

As described above, the concentration of the reducing component contained in the exhaust increases as the fuel concentration of the air-fuel ratio upstream of the NOx storage reduction catalyst becomes higher than the stoichiometric air-fuel ratio. Further, in this case, the reducing component is sucked into the internal combustion engine. The larger the intake air amount, the larger the exhaust amount, and therefore the total reducing component amount.

Therefore, the inflow reducing agent amount detecting means determines the reducing agent amount that has flown into the NOx storage reduction catalyst based on the intake air amount detected by the intake air amount detecting means and the air-fuel ratio detected by the air-fuel ratio detecting means. It can be easily detected. As a result, the reduction amount detecting means can obtain the NOx reduction amount with high accuracy.

According to a fourteenth aspect of the invention, there is provided an exhaust gas purification catalyst reduction amount detecting device for an internal combustion engine according to any one of the eleventh to thirteenth aspects, wherein a deterioration degree detecting means for detecting a deterioration degree of the NOx occlusion reduction catalyst and the NOx occlusion. And a catalyst bed temperature detecting means for detecting the bed temperature of the reducing catalyst, wherein the reducing agent permeability detecting means determines the transmittance based on the detection value of the deterioration degree detecting means and the detection value of the catalyst bed temperature detecting means. It is characterized by detecting.

As described above, it has been found that the permeability of the reducing agent in the NOx storage reduction catalyst changes depending on the degree of deterioration of the NOx storage reduction catalyst and the bed temperature of the NOx storage reduction catalyst. Therefore, the reducing agent permeation rate detecting means easily determines the permeation rate based on the deterioration degree of the NOx occlusion reduction catalyst detected by the deterioration degree detecting means and the bed temperature of the NOx occlusion reduction catalyst detected by the catalyst bed temperature detecting means. Can be obtained with high accuracy. As a result, the reduction amount detecting means can obtain the NOx reduction amount with high accuracy.

According to a fifteenth aspect of the present invention, there is provided the exhaust gas purification catalyst reduction amount detection device for an internal combustion engine according to the fourteenth aspect.
The NOx storage reduction catalyst is provided with sulfur poisoning detection means for detecting sulfur poisoning to the storage reduction catalyst, and the deterioration degree detection means determines the degree of sulfur poisoning of the NOx storage reduction catalyst detected by the sulfur poisoning detection means. It is characterized in that it is detected as the degree of deterioration of the storage reduction catalyst.

Since the cause of the deterioration degree of the NOx storage reduction catalyst which affects the above-mentioned transmittance is mainly due to sulfur poisoning, the deterioration degree detecting means determines the degree of sulfur poisoning detected by the sulfur poisoning detecting means. By using, it is possible to easily and highly accurately detect the degree of deterioration of the NOx storage reduction catalyst. As a result, the reducing agent transmittance detecting means can obtain highly accurate transmittance, and the reducing amount detecting means can accurately detect NO.
The x reduction amount can be obtained.

According to a sixteenth aspect of the present invention, there is provided the exhaust gas purification catalyst reduction amount detecting device for an internal combustion engine according to the fourteenth or fifteenth aspects, wherein the deterioration degree detecting means is responsive to the detected value of the catalyst bed temperature detecting means. It is characterized in that the degree of deterioration of the catalyst is set.

As described above, the degree of deterioration of the NOx occlusion reduction catalyst changes depending on the bed temperature of the NOx occlusion reduction catalyst, and even if the bed temperature changes, the degree of deterioration cannot be determined with high accuracy. Therefore, the deterioration degree detecting means sets the deterioration degree in accordance with the bed temperature of the NOx storage reduction catalyst detected by the catalyst bed temperature detecting means. This makes it possible to set an appropriate degree of deterioration. In this way, the reducing agent transmittance detecting means can obtain a highly accurate transmittance, and the reducing amount detecting means can obtain the NOx reducing amount with high accuracy.

An exhaust gas purification catalyst reduction amount detection device for an internal combustion engine according to a seventeenth aspect is the one according to any one of the fourteenth to sixteenth aspects, further comprising NOx storage capacity detection means for detecting a NOx storage capacity of the NOx storage reduction catalyst, The deterioration degree detecting means detects the NOx storage capacity detecting means and the NOx storage capacity detecting means.
The deterioration degree of the NOx storage reduction catalyst is detected based on the NOx storage capacity of the x storage reduction catalyst when it is not used.

As described above, the deterioration degree detecting means determines N based on the NOx storage capacity when the NOx storage reduction catalyst is not used and the current NOx storage capacity detected by the NOx storage capacity detecting means.
The degree of deterioration of the Ox storage reduction catalyst can be obtained with high accuracy. As a result, the reducing agent transmittance detecting means can obtain a highly accurate transmittance, and the reducing amount detecting means can accurately detect the NO.
The x reduction amount can be obtained.

In the exhaust gas purification management device for an internal combustion engine according to claim 18, the exhaust gas purification catalyst reduction amount detection device for an internal combustion engine according to any one of claims 11 to 17 and exhaust gas based on the operating state of the internal combustion engine. Exhaust gas purification control based on the NOx amount detection means for obtaining the NOx amount, the reduction amount of the NOx storage reduction catalyst obtained by the exhaust purification catalyst reduction amount detection device, and the NOx amount obtained by the NOx amount detection means. And an exhaust gas purification management means for executing the above.

Since the reduction amount for the NOx occlusion reduction catalyst and the NOx amount in the exhaust gas are directly related to the NOx occlusion state in the NOx occlusion reduction catalyst, the exhaust gas purification management means is any one of claims 11 to 17. The exhaust purification catalyst reduction amount detection device obtains the reduction amount, and further the NOx amount detection means detects NOx.
We get the amount and carry out exhaust gas purification management. Since the reduction amount detected with high accuracy is used in this way, the exhaust gas purification management means can perform highly accurate exhaust gas purification management.

According to a nineteenth aspect of the present invention, in the exhaust gas purification management device for an internal combustion engine according to the eighteenth aspect, the exhaust gas purification management means is the reduction amount of the NOx storage reduction catalyst obtained by the exhaust purification catalyst reduction amount detection device. The exhaust gas purification control is executed based on the NOx storage amount of the NOx storage reduction catalyst calculated by the balance calculation with the NOx amount obtained by the NOx amount detection means.

Thus, by using the reduction amount obtained by the exhaust purification catalyst reduction amount detection device according to any one of claims 11 to 17 in the balance calculation of the reduction amount and the NOx amount, the NOx storage of the NOx storage reduction catalyst Since the amount can be obtained with high accuracy, the exhaust gas purification management means can perform highly accurate exhaust gas purification management.

An exhaust purification catalyst NOx storage amount calculation device for an internal combustion engine according to claim 20 is based on the exhaust purification catalyst reduction amount detection device for an internal combustion engine according to any one of claims 11 to 17 and an operating state of the internal combustion engine. To obtain the amount of NOx in the exhaust gas N
The NOx storage reduction catalyst is calculated based on the balance between the reduction amount of the NOx storage reduction catalyst obtained by the exhaust purification catalyst reduction amount detection device and the NOx amount obtained by the NOx amount detection means. And a NOx occlusion amount calculation means for calculating the NOx occlusion amount.

By using the reduction amount obtained by the exhaust purification catalyst reduction amount detection device according to any one of claims 11 to 17 in the balance calculation of the reduction amount and the NOx amount, the NOx storage amount calculation means is N of NOx storage reduction catalyst
The Ox storage amount can be obtained with high accuracy.

[0049]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [Embodiment 1] FIG. 1 shows a cylinder injection type gasoline engine (hereinafter abbreviated as "engine") 2 mounted on a vehicle and its electronic control unit (hereinafter "E").
(Hereinafter referred to as "CU") 4. Engine 2
Includes a fuel injection valve 6 for directly injecting fuel into the combustion chamber of each cylinder, and a spark plug 8 for igniting the injected fuel.
And are provided respectively. A throttle valve 12 whose opening is adjusted by a motor is provided in the middle of an intake path 10 connected to the combustion chamber via an intake valve (not shown). The intake air amount GA (mg / sec) supplied to each cylinder is adjusted by the opening of the throttle valve 12 (throttle opening TA). Throttle opening T
A is detected by the throttle opening sensor 14, and the intake air amount GA is detected by the intake air amount sensor 16 (corresponding to intake air amount detecting means) and read by the ECU 4.

The NOx storage reduction catalyst 2 is provided in the middle of the exhaust path 18 connected to the combustion chamber via an exhaust valve (not shown).
0 is provided. An air-fuel ratio sensor 22 for detecting an air-fuel ratio from an exhaust component is provided upstream of the NOx storage reduction catalyst 20.
(Corresponding to air-fuel ratio detecting means), and NOx storage reduction catalyst 2
An O2 sensor 2 for detecting oxygen in exhaust components is provided downstream of 0.
4 are provided respectively.

The ECU 4 is an engine control circuit mainly composed of a digital computer. This EC
In addition to the throttle opening sensor 14, the intake air amount sensor 16, the air-fuel ratio sensor 22 and the O2 sensor 24, U4 is the depression amount of the accelerator pedal 26 (accelerator opening ACC
P), an accelerator opening sensor 28, an engine speed sensor 30 that detects an engine speed NE from the rotation of a crankshaft (not shown), a cooling water temperature THW of the engine 2.
Signals are input from the cooling water temperature sensor 32 for detecting the In addition to such sensors, although not shown, sensors such as a vehicle speed sensor necessary for engine control are provided.

The ECU 4 appropriately controls the fuel injection timing, the fuel injection amount, the ignition timing and the throttle opening TA of the engine 2 based on the contents detected by the various sensors described above. As a result, for example, the combustion mode is switched between stratified combustion and homogeneous combustion. In the first embodiment, the combustion mode is determined on the basis of the map of the engine speed NE and the load factor eklq during normal operation excluding the cold state. Here, the load factor eklq indicates the ratio of the current load to the maximum engine load, for example, the accelerator opening ACCP.
Is a value obtained from a map with the engine rotation speed NE as a parameter.

Next, of the control executed by the ECU 4 in the present embodiment, a process relating to exhaust gas purification management for the NOx storage reduction catalyst 20 will be described. FIG. 2 is a rich spike setting process, which is repeatedly executed at regular time intervals. When this process is started, first, the NOx emission amount per unit time enoxextrate (mg /
sec) is a map Menoxextrate (eklq, based on the load factor eklq and the engine speed NE.
It is calculated from NE) (S110). Map Me here
noxextrate (eklq, NE) is the load factor ek
It is a map which shows the amount of NOx emissions (mg / sec) per unit time previously obtained by an experiment using lq and engine speed NE as parameters. The map Menoxextrate (eklq, NE) is switched between stratified combustion and homogeneous combustion. If the homogeneous combustion has a stoichiometric air-fuel ratio or a fuel concentration higher than the stoichiometric air-fuel ratio, N
Since there is almost no Ox emission, NOx emission enoxextrate = 0 (mg / se
It may be c).

The NOx emission amount e per unit time
The NOx emission amount enoxext (mg) emitted in the current control cycle is calculated by the product of noxextrate and the control cycle (sec) of this processing (S11).
2). That is, this time, the amount of NOx stored in the NOx storage reduction catalyst 20 is calculated.

Next, the NOx reduction amount enox per unit time
readrate (mg / sec) is read (S1
14). NOx reduction amount per unit time enoxre
"drate" is a value calculated in the NOx reduction amount detection process (FIG. 4) per unit time described later. Then, the NOx reduction amount enoxred in the current control cycle is calculated (mg) by the product of the NOx reduction amount per unit time enoxreduce and the control cycle of this processing (S).
116). That is, the reduction amount (mg) of NOx stored in the NOx storage reduction catalyst 20 is calculated.

Next, the NOx storage amount enoxc is calculated by the following equation 1.
nt (mg) is updated (S118).

[0057]

[Equation 1] enoxcnt ← enoxcnt + enoxext-enoxred ... [Formula 1] Here, enoxcnt on the right side is N in the previous control cycle.
It is the Ox storage amount, and the NOx storage amount in which the left side enoxcnt is updated.

Next, the NOx storage capacity noxmax (mg)
Is calculated (S120). This NOx storage capacity nox
max is the catalyst bed temperature and NOx storage capacity nox shown in FIG.
It is calculated based on the catalyst bed temperature from a map Mnoxmax (here, a map marked with Δ) showing a relationship with max.

In the NOx storage reduction catalyst 20, since the NOx storage capacity differs depending on the catalyst bed temperature, the map Mno is
In xmax, the catalyst bed temperature is divided into a plurality of areas, in FIG. 3, seven bed temperature areas tmp (1) to tmp (7), and the NOx storage capacity is held for each bed temperature area. Incidentally, the NOx storage capacity indicated by a circle in FIG. 3 is the NOx storage reduction catalyst 20.
Represents the NOx storage capacity when it was unused (undegraded), and the NOx storage capacity represented by a triangle represents the current NOx storage capacity of the NOx storage reduction catalyst 20. That is, it can be seen that the current NOx storage reduction catalyst 20 has its NOx storage capacity lower than when it is not used due to deterioration (mainly sulfur poisoning).

Therefore, in step S120, the catalyst bed temperature etempave is determined, and this catalyst bed temperature ettempa is determined.
Depending on the position of ve, the NOx storage capacity (marked by Δ) in the two bed temperature regions tmp (3) and tmp (4) as shown in FIG.
The NOx storage capacity noxmax is obtained by performing an interpolation calculation using

It should be noted that the catalyst bed temperature etemptave is determined by the ECU
It is estimated from the engine speed NE and the intake air amount GA by a floor temperature estimation process separately performed in 4. As the bed temperature estimation processing, for example, the catalyst bed temperature can be estimated as an exhaust temperature obtained from the engine speed NE and the intake air amount GA during stable operation of the engine 2. And engine 2
During the transition of, the catalyst bed temperature is calculated by repeating and calculating the catalyst bed temperature so as to follow the exhaust gas temperature based on the time constant of the intake air amount GA. still,
Instead of estimating in this way, a temperature sensor may be provided in the NOx storage reduction catalyst 20 and the catalyst bed temperature may be directly measured and used.

Next, it is determined whether or not the NOx storage amount enoxcnt obtained by the above equation 1 is greater than or equal to the NOx storage capacity noxmax (S122). Where enoxcnt <
If it is noxmax (“NO” in S122),
Next, it is determined whether or not the NOx storage amount enoxcnt is "0" or more (S124). If enoxcnt ≧ 0 (“YES” in S124), this processing is temporarily terminated.

If enoxcnt <0 (S12)
4 is “NO”), and the NOx storage amount enoxcnt is “0”
Is set (S126), and this processing is once ended. On the other hand, if enoxcnt ≧ noxmax, (S
At 122, "YES"), and then parameters for rich spike are set to execute rich spike (S12).
8). The rich spike parameters include, for example, the rich spike air-fuel ratio AFr and the rich spike period R.
spt is set according to the value of the NOx storage capacity noxmax or the like.

In this way, this processing is once terminated. By setting the rich spike parameter in this way, the rich spike is started by the fuel injection amount control by the ECU 4, and the fuel concentration of the air-fuel mixture in the combustion chamber is temporarily set to a state sufficiently higher than the theoretical air-fuel ratio. Exhaust route 1
A large amount of unburned gas such as HC and CO is discharged to 8.
As a result, in the rich spike setting process (FIG. 2), the NOx reduction amount enoxredr per unit time.
ate rises (S114), and NOx reduction amount enoxr
Since ed increases (S116), the NOx storage amount eno
xcnt sharply decreases toward "0".

FIG. 4 shows the NOx reduction amount en per unit time.
NO per unit time to obtain oxredrate
The x reduction amount detection processing is shown. This process is repeatedly executed at regular time intervals. When this processing is started, first, the NOx storage reduction catalyst 2 obtained from the output of the air-fuel ratio sensor 22.
The current value of the air-fuel ratio AF on the upstream side of 0 is read (S210). Then, the value of the intake air amount GA obtained from the output of the intake air amount sensor 16 is read (S21
2).

Next, the map Meredutm (AF, G
From A), the supply reducing agent amount eredutm per unit time is calculated based on the air-fuel ratio AF and the intake air amount GA (S214). Here, the map Meredutm (AF,
GA) is the air-fuel ratio AF and the intake air amount GA previously experimentally
This is a map set by measuring the amount of unoxidized fuel component existing in the exhaust gas (mg / sec) with and as parameters. For example, the map Meredutm (AF, G
In A), in particular, on the side where the air-fuel ratio AF is lower than the theoretical air-fuel ratio, the lower the air-fuel ratio AF is, the more the supply reducing agent amount eredutm per unit time increases, and the air-fuel ratio AF is lower than the theoretical air-fuel ratio. The intake air amount GA on the side is set so that the supply reducing agent amount eredutm per unit time increases, and the air-fuel ratio AF is higher than the stoichiometric air-fuel ratio.
When the value of is high, it is almost "0 (mg / sec)".
Is set to.

Next, the catalyst bed temperature etemptave is read (S216). The detection of the catalyst bed temperature “etempave” is as described above. Next, the initial NOx storage capacity n
oxmaxinit is read (S218). This initial NOx storage capacity noxmaxinit is the NOx storage capacity of the NOx storage / reduction catalyst 20 when it is unused (not deteriorated), and from the map of the unused NOx storage / reduction catalyst (marked with a circle) in the aforementioned map Mnoxmax, Catalyst bed temperature e
Based on the temperature, it is obtained as shown in FIG.

Next, the current NOx storage capacity noxmax
Is the current NOx in the map Mnoxmax described above.
It is read from the map of the storage reduction catalyst (marked by Δ) as shown in FIG. 3 (S220).

Next, as shown in the following equation 2, the degree of catalyst deterioration esoxr
audio (%) is calculated (S222). The degree of catalyst deterioration esoxratio mainly corresponds to sulfur poisoning.

[0070]

[Equation 2] esoxratio ← 100 × noxmax / noxmaxinit ... [Equation 2] Next, the map Mepassr (etempave, eso
xratio), based on the catalyst bed temperature etemptave and the degree of catalyst deterioration esoxratio, the catalyst permeability e
Passr (%) is calculated (S224). The catalyst permeability epassr represents the degree to which the reducing agent (unoxidized fuel component) in the exhaust gas passes through the NOx storage reduction catalyst 20 without being oxidized.

Next, as shown in the following expression 3, NOx per unit time
The reduction amount enoxredrate is calculated (S22
6).

[0072]

## EQU00003 ## enoxreduce.rarw.Krn.times.eredutm.times. (100-epassr) / 100 [Formula 3] The right side of Formula 3 represents the amount of the reducing agent oxidized in the NOx storage reduction catalyst 20. Krn is NO from the amount of reducing agent
x is a conversion coefficient to the reduction amount. Since the NOx is reduced by oxidizing the reducing agent, the value on the right side of the equation 3 indicates the NOx reduction amount enoxreduce per unit time.

In this way, this processing is once terminated. By repeating such processing, NO per unit time
The x reduction amount enoxupdate is repeatedly updated. FIG. 5 shows the NOx storage capacity updating process for obtaining the current NOx storage capacity noxmax. This process is a process that is repeatedly executed at regular time intervals. When this process is started, it is first determined whether or not the rich spike execution flag Fspk is "ON" (S310). The rich spike execution flag Fspk is a flag that is set to “ON” when the rich spike is started.

If Fspk = “OFF” (S310)
Then, “NO”), and this processing is once terminated. If Fspk = "ON" due to the start of the rich spike (S
If YES in 310, then it is determined whether or not the output of the O2 sensor 24 has changed to the rich side (S31).
2). This change to the rich side is caused by the NOx storage reduction catalyst 2
When the reduction of the total amount of NOx stored in 0 is completed, N
This is because the timing at which the exhaust gas downstream of the Ox storage reduction catalyst 20 temporarily changes to the rich side is captured.

If the O2 sensor 24 has not changed to the rich side ("NO" in S312), it is next determined whether or not it is before the time limit after the end of the rich spike (S314). This time limit is a time limit for detecting a change in the output of the O2 sensor 24 to the rich side after the rich spike ends.

If it is before the time limit ("Y" in S314).
ES ”), the present process is temporarily terminated. If there is a temporary change to the rich side indicating the completion of NOx reduction in the O2 sensor 24 before the time limit (“YES” in S312), then the output state of the O2 sensor 24,
Here, the NOx storage capacity correction value dnoxmax is calculated based on the timing of the output change to the rich side (S
316).

For example, the current NOx storage capacity noxmax, which is set as indicated by a triangle mark in FIG. 3, is N.
When the actual NOx storage capacity of the Ox storage / reduction catalyst 20 matches, the timing at which the rich side change appears in the O2 sensor 24 from the start or end of the rich spike is set as the reference timing. If the actual timing is earlier than the reference timing, the actual NOx storage capacity is smaller than the NOx storage capacity noxmax on the map.
The NOx storage capacity correction value dnoxmax is set to a plus value having a large absolute value according to the speed of the timing. On the contrary, if the actual timing is later than the reference timing, the actual NOx storage capacity is larger than the NOx storage capacity noxmax on the map. Therefore, depending on the timing delay, the map shows a large negative value of the absolute value as the NOx storage capacity. The correction value dnoxmax is set.

Thus, the NOx storage capacity correction value dnoxm
Once ax is calculated, the NOx storage capacity noxmax in the map Mnoxmax indicated by the triangle mark in FIG. 3 is next calculated.
The correction of (i) is executed as shown in the following Expression 4 (S31
8).

[0079]

[Mathematical formula-see original document] noxmax (i) <-noxmax (i) -dnoxmax ... [Equation 4] Here, (i) represents the bed temperature region to which the current catalyst bed temperature etempave belongs. For example, in the example of FIG.
The floor temperature region tmp (4) corresponds to this floor temperature region tmp.
The value of Δ in (4) corresponds to noxmax (i).

Next, "OFF" is set to the rich spike execution flag Fspk (S320), and this processing is once terminated. As a result, in the next control cycle, step S
At 310, the determination is “NO”, and the substantial process is not performed until the next rich spike is started.

On the other hand, even if the time limit elapses, the O2 sensor 2
If the output of No. 4 does not show a temporary change to the rich side (“NO” in S314), in this case also the step S
The processing of 316 to S320 is executed. In this case, in step S316, the actual rich change timing is later than the reference timing in correspondence with the time limit. Therefore, the actual NOx storage capacity is NO on the map.
It is determined that it is larger than the x storage capacity noxmax, and a negative value having a large absolute value is set to the NOx storage capacity correction value dnoxmax according to the timing delay. Then, in step S318, the NOx storage capacity n
oxmax (i) is increased.

In the above configuration, N per unit time
Steps S210 to S2 of the Ox reduction amount detection processing (FIG. 4)
14 is processing as inflow reducing agent amount detecting means, step S224 is processing as reducing agent permeability detecting means, step S226 is processing as reducing amount detecting means, and step S216 is processing as catalyst bed temperature detecting means. In addition, steps S218 to S222 are processing as deterioration degree detection means, NOx storage capacity update processing (FIG. 5) is processing as NOx storage capacity detection means, and steps S110 and S112 of rich spike setting processing (FIG. 2) are performed. Steps S114 to S128 are performed as the exhaust purification management means, and step S118 is performed as the NOx amount detection processing.
This corresponds to the processing as the storage amount calculation means.

According to the first embodiment described above, the following effects can be obtained. (I). When a reducing agent is passed through the NOx storage reduction catalyst 20 by a rich spike to reduce the NOx stored in the NOx storage reduction catalyst 20, even if the NOx storage reduction catalyst 20 has a sufficient NOx storage amount. ,
Not all of the passing reducing agent is oxidized and contributes to the reducing action. That is, a part of the reducing agent is not completely oxidized inside the NOx storage reduction catalyst 20 and is discharged from the NOx storage reduction catalyst 20. Therefore, a highly accurate NOx reduction amount cannot be obtained unless the transmittance, which is the ratio of the unoxidized portion of the reducing agent, is taken into consideration.

In the present embodiment, NOx per unit time
Catalyst reduction rate epassr by reduction amount detection processing (FIG. 4)
To set the NOx reduction amount per unit time with high accuracy
Seeking oxredrate. Therefore, the NOx reduction amount enoxredrate per unit time can be used to calculate the NOx reduction amount enoxred with high precision (FIG. 2: S116), and the NOx storage amount enoxcnt can also be obtained with high precision (FIG. 2: S118). Therefore, highly accurate exhaust gas purification management can be performed, the timing of rich spike can be appropriately determined, and an appropriate amount of rich spike can be performed, so that fuel is not wasted and NOx is not emitted to the outside.

(B). The catalyst permeability epassr is the catalyst deterioration degree esoxratio and the catalyst bed temperature etemptave.
Since it is set according to, the highly accurate catalyst permeability ep
Assr can be obtained, and a highly accurate NOx reduction amount can be obtained.

(C). The catalyst deterioration degree esoxrati
o is set from the initial NOx storage capacity noxmaxinit and the NOx storage capacity noxmax that are obtained according to the catalyst bed temperature etmave. Therefore, a highly accurate value can be easily obtained.

Further, as described above, the degree of catalyst deterioration esorat
Since io is set corresponding to the catalyst bed temperature etemptave, it is possible to obtain an appropriate degree of catalyst deterioration esoxratio even if the catalyst bed temperature etemptave changes. Therefore, more accurate catalyst permeability epas
Since sr is obtained, a highly accurate NOx reduction amount can be obtained.

[Embodiment 2] In the present embodiment, O2
NOx storage capacity nox based on the output state of the sensor 24
Instead of updating max, the NOx storage capacity no is calculated by calculating the sulfur poisoning state of the NOx storage reduction catalyst 20.
xmax is updated. Therefore, in the present embodiment, the sulfur poisoning NOx storage capacity updating processing of FIG. 6 is executed instead of the NOx storage capacity updating processing (FIG. 5).

The sulfur poisoning NOx storage capacity updating process (FIG. 6) is a process which is repeatedly executed at regular intervals. When this process is started, first, the sulfur poisoning increase amount esoxincra per unit time for the NOx storage reduction catalyst 20 in the bed temperature region i to which the catalyst bed temperature etempave belongs.
te (i) is a map Mesoxinrate (fuel type, AF, GA, etemptave), from the type of fuel currently used, air-fuel ratio AF, intake air amount GA,
It is calculated on the basis of the catalyst bed temperature "etempave" (S4
10).

This map Mesoxinrate (fuel type, AF, GA, etemptave) is a map that has been previously obtained by experiments according to each parameter. The type of fuel currently used here is a parameter because, for example, high octane gasoline has a lower sulfur content than regular gasoline. In this type of fuel determination, for example, in the case of high octane gasoline, knocking is less likely to occur, so the ignition advance angle is set to a large value by the ignition advance control, and in the case of regular gasoline, the ignition advance angle is set to a small value. Therefore, the type can be determined based on the ignition advance angle. Air-fuel ratio AF, intake air amount GA and catalyst bed temperature etem
The pave is related to the amount of sulfur supplied and the reaction rate of poisoning.

The product of the amount of increased sulfur poisoning per unit time esoxincrate (i) thus obtained and the control cycle of this processing is calculated, and the NOx storage reduction catalyst in the bed temperature region i in this control cycle is calculated. The sulfur poisoning increase amount esoxinc (i) for 20 is calculated (S41).
2).

Next, the sulfur poisoning recovery amount es per unit time for the NOx storage reduction catalyst 20 in the bed temperature region i
oxdecrate (i) is the map Mesoxdecr
ate (esox (i), AF, GA, etempav
From e), sulfur poisoning amount esox (i), air-fuel ratio AF,
It is calculated based on the intake air amount GA and the catalyst bed temperature etmave (S414). Where sulfur poisoning amount esox
(I) is the sulfur poisoning amount in the bed temperature region i, and NO
x The amount of the storage reduction catalyst 20 actually poisoned under the bed temperature region i. The larger the sulfur poisoning amount esox (i), the larger the amount of sulfur released from the NOx storage reduction catalyst 20. The air-fuel ratio AF and the intake air amount GA are related to the amount of the component that reduces sulfur, and the catalyst bed temperature etemptave is related to the desorption rate.

Using the sulfur poisoning recovery amount esoxdecrate (i) per unit time thus obtained, as shown in the following equation 5, the sulfur poisoning recovery amount esoxdec in the bed temperature region i in the present control cycle is expressed. (I) is calculated (S416).

[0094]

[Equation 5] esoxdec (i) ← esoxdecrate (i) x control period x kdec (i) ... [Equation 5] Here, kdec (i) is a sulfur poisoning recovery correction coefficient, and is a floor temperature region poisoned at a low temperature. Since sulfur is more likely to be released, a larger value is set in the lower bed temperature region i.

Next, the sulfur poisoning amount esox (i) is calculated according to the following equation 6 based on the sulfur poisoning increase amount esoxinc (i) and the sulfur poisoning recovery amount esoxdec (i) obtained this time ( S418).

[0096]

[Equation 6] esox (i) ← esox (i) + esoxinc (i) -esoxdec (i) [Equation 6] where esox (i) on the right side is the sulfur coverage of the bed temperature region i in the previous control cycle. It is the poison amount, and esox (i) on the left side is the sulfur poisoning amount of the bed temperature region i updated this time.

Next, the NOx storage capacity noxmax (i) in the bed temperature region i is calculated as shown in the following equation 7 (S).
420).

[0098]

[Equation 7] noxmax (i) ← noxmaxinit (i) -esox (i) [Equation 7] Next, even if the catalyst bed temperature etempave indicates the bed temperature region i, for each bed temperature region other than the bed temperature region i At the same time, recovery of sulfur poisoning occurs, so the next steps S422-S
By 428, the sulfur poisoning recovery process is executed. In addition,
Although each step will be described as one process, it is assumed that each step is executed for each bed temperature region other than the bed temperature region i (6 bed temperature regions are targets in the example of FIG. 3).

That is, the same processing as step S414 is executed for each bed temperature region other than the bed temperature region i,
The sulfur poisoning recovery amount esoxdecrate (other than i) per unit time for the NOx storage reduction catalyst 20 is calculated (S422).

Then, the sulfur poisoning recovery amount esoxdec (other than i) in each bed temperature region other than the bed temperature region i in the present control cycle is calculated by the above equation 5 (S424).
Then, the sulfur poisoning amount esox (other than i) in each bed temperature region other than the bed temperature region i is calculated based on each sulfur poisoning recovery amount esoxdec (other than i) obtained this time as shown in the following equation 8. (S426).

[0101]

[Equation 8] esox (other than i) ← esox (other than i) -esoxdec (other than i) ... [Equation 8] Next, according to the above Equation 7, each NOx storage capacity noxmax (i Other than) is calculated (S428).

In this way, this process is once terminated. By repeating such processing, the NOx storage capacity noxmax (i) of the bed temperature region i and the NOx storage capacity noxmax (other than i) of each bed temperature region other than the bed temperature region i are updated. As a result, the map (marked with Δ) in FIG. 3 is updated and the NOx reduction amount enox per unit time in the process of FIG.
Used to calculate redrate.

In the above structure, sulfur poisoning NOx
Steps S410 to S41 of the storage capacity update process (FIG. 6)
8, S422 to S426 are steps S420, S428, and S2 for processing as sulfur poisoning detection means.
18 to S222 (FIG. 4) correspond to the process as the deterioration degree detecting means.

According to the second embodiment described above, the following effects can be obtained. (I). The effects (a) to (c) of the first embodiment are produced. (B). Since the NOx storage capacity noxmax (i) can be updated without waiting for the rich spike, the error from the actual NOx storage capacity can be kept small at all times.

[Other Embodiments] (a). Combining the first embodiment and the second embodiment, the NOx storage capacity noxmax (i) is frequently set in the sulfur poisoning NOx storage capacity update process (FIG. 6) from the rich spike to the rich spike. Alternatively, the error may be corrected by the output of the O2 sensor 24 by the NOx storage capacity updating process (FIG. 5) during the rich spike. As a result, the NOx reduction amount enoxre
d, NOx storage amount enoxcnt and NOx storage capacity n
oxmax can be obtained with higher accuracy, and more accurate exhaust gas purification management becomes possible.

(B). In each of the above-described embodiments, the in-cylinder injection type engine is used, but it is also applicable to a port injection type engine that injects fuel into the intake port. In the case of this configuration, lean combustion is performed instead of stratified combustion, and during this lean combustion, NOx is stored in the NOx storage reduction catalyst.

(C). In each of the above embodiments, N
Although a configuration in which no other catalyst is arranged on the upstream side of the Ox storage reduction catalyst 20 is shown, for example, a three-way catalyst having an oxygen storage function for removing HC and CO components released in large quantities at the time of engine start A start catalystist may be placed. In this case, in response to the start catalyst oxidizing the unburned components in the exhaust during the rich spike, particularly in step S316 (FIG. 5), NOx is discharged.
The NOx storage capacity correction value dnoxmax is calculated in consideration of the arrival delay time of the unburned component to the storage reduction catalyst 20.

[Brief description of drawings]

FIG. 1 is a schematic configuration explanatory diagram of an engine and an ECU according to a first embodiment.

FIG. 2 is a flowchart of a rich spike setting process executed by the ECU of the first embodiment.

FIG. 3 is an explanatory diagram of a map showing a relationship between a catalyst bed temperature and a NOx storage capacity.

FIG. 4 is a flowchart of NOx reduction amount detection processing per unit time executed by the ECU of the first embodiment.

FIG. 5 is a flow chart of NOx storage capacity update processing.

FIG. 6 is a sulfur poisoning N executed by the ECU of the second embodiment.
The flowchart of Ox storage capacity update processing.

[Explanation of symbols]

2 ... Engine, 4 ... ECU, 6 ... Fuel injection valve, 8 ...
Spark plug, 10 ... Intake passage, 12 ... Throttle valve, 14 ... Throttle opening sensor, 16 ... Intake air amount sensor, 18 ... Exhaust passage, 20 ... NOx storage reduction catalyst, 2
2 ... Air-fuel ratio sensor, 24 ... O2 sensor, 26 ... Accelerator pedal, 28 ... Accelerator opening sensor, 30 ... Engine speed sensor, 32 ... Cooling water temperature sensor.

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) F02D 45/00 314 F02D 45/00 368G B01D 53/36 101A 368 ZAB F term (reference) 3G084 BA04 BA05 BA09 BA13 DA27 FA07 FA10 FA13 FA20 FA26 FA27 FA28 FA29 3G091 AA02 AA17 AA24 AA28 AB04 AB06 AB09 BA01 BA14 BA33 CA16 DB07 DB10 EA01 EA05 EA07 EA10 EA18 EA19 EA22 EA33 FA01 HA36 HA37 4D048 AA06 AB02 AC10 BC01 DA01 DA02 DA08 DA08 DA08 DA08 DA09

Claims (20)

[Claims] 1. A method for detecting an exhaust purification catalyst reduction amount of an internal combustion engine comprising an NOx storage reduction catalyst in an exhaust system, comprising: a reducing agent amount flowing into the NOx storage reduction catalyst;
Based on the transmittance of the reducing agent in the Ox storage reduction catalyst,
An exhaust gas purification catalyst reduction amount detection method for an internal combustion engine, comprising detecting a reduction amount in the NOx storage reduction catalyst. 2. The internal combustion engine according to claim 1, wherein the amount of the reducing agent that has flowed into the NOx storage reduction catalyst is detected as the amount of reducing component contained in the exhaust gas discharged from the combustion chamber of the internal combustion engine. Exhaust purification catalyst reduction amount detection method. 3. The method according to claim 2, wherein the amount of reducing agent flowing into the NOx storage reduction catalyst is detected based on the amount of intake air taken into the internal combustion engine and the air-fuel ratio upstream of the NOx storage reduction catalyst. A method for detecting an exhaust purification catalyst reduction amount of an internal combustion engine. 4. The N according to claim 1,
An exhaust gas purification catalyst reduction amount detection method for an internal combustion engine, comprising: detecting the permeability based on a degree of deterioration of an Ox storage reduction catalyst and a bed temperature of the NOx storage reduction catalyst. 5. The method for detecting an exhaust gas purification catalyst reduction amount of an internal combustion engine according to claim 4, wherein the degree of deterioration of the NOx storage reduction catalyst is detected as a degree of sulfur poisoning of the NOx storage reduction catalyst. . 6. The exhaust gas purification catalyst reduction amount detection of an internal combustion engine according to claim 4 or 5, wherein the degree of deterioration of the NOx storage reduction catalyst is set according to the bed temperature of the NOx storage reduction catalyst. Method. 7. The N according to any one of claims 4 to 6.
The exhaust gas purification catalyst reduction amount detection method for an internal combustion engine, wherein the degree of deterioration of the Ox storage reduction catalyst is obtained based on an unused NOx storage capacity of the NOx storage reduction catalyst and a current NOx storage capacity. 8. The NOx storage reduction catalyst reduction amount detection method for an internal combustion engine according to claim 1, wherein the reduction amount of the NOx storage reduction catalyst is obtained, and the NOx amount in the exhaust gas is determined based on the operating state of the internal combustion engine. The exhaust gas purification management method for an internal combustion engine is characterized in that the exhaust gas purification management is executed based on the NOx amount and the reduction amount. 9. The method according to claim 8, based on the reduction amount of the NOx storage reduction catalyst and the operating state of the internal combustion engine, which are obtained by the exhaust purification catalyst reduction amount detection method for an internal combustion engine according to any one of claims 1 to 7. NOx of the NOx storage-reduction catalyst calculated by the balance calculation with the calculated NOx amount in the exhaust gas
An exhaust gas purification management method for an internal combustion engine, characterized in that exhaust gas purification management is executed based on the stored amount. 10. The NOx obtained by the exhaust gas purification catalyst reduction amount detection method for an internal combustion engine according to claim 1.
An NOx storage amount of the NOx storage / reduction catalyst is calculated by a balance calculation of the reduction amount of the storage / reduction catalyst and the NOx amount in the exhaust gas obtained based on the operating state of the internal combustion engine. Purification catalyst NOx storage amount calculation method. 11. An exhaust gas purification catalyst reduction amount detection device for an internal combustion engine, comprising an NOx storage reduction catalyst in an exhaust system, and an inflow reducing agent amount detection means for detecting an amount of reducing agent flowing into the NOx storage reduction catalyst. Reducing agent permeability detecting means for detecting the reducing agent permeability in the NOx occlusion reducing catalyst, reducing agent amount detected by the inflow reducing agent amount detecting means, and reducing agent permeability detecting means An exhaust gas purification catalyst reduction amount detection device for an internal combustion engine, comprising: a reduction amount detection means for detecting a reduction amount in the NOx storage reduction catalyst based on the determined transmittance. 12. The inflow reducing agent amount detecting means according to claim 11, wherein the reducing component amount contained in the exhaust gas discharged from the combustion chamber of the internal combustion engine is detected as the reducing agent amount flowing into the NOx storage reduction catalyst. An exhaust gas purification catalyst reduction amount detection device for an internal combustion engine, comprising: 13. An intake air amount detecting means for detecting an intake air amount sucked into an internal combustion engine, and an air-fuel ratio detecting means for detecting an air-fuel ratio from an exhaust component upstream of the NOx storage reduction catalyst according to claim 12. The inflow reducing agent amount detecting means detects the reducing agent amount flowing into the NOx storage reduction catalyst based on the detection value of the intake air amount detecting means and the detection value of the air-fuel ratio detecting means. Exhaust gas purification catalyst reduction amount detection device for internal combustion engine. 14. The method according to any one of claims 11 to 13,
A deterioration degree detection unit that detects a deterioration degree of the NOx storage reduction catalyst, and a catalyst bed temperature detection unit that detects a bed temperature of the NOx storage reduction catalyst, wherein the reducing agent permeability detection unit is the deterioration degree detection unit. An exhaust gas purification catalyst reduction amount detection device for an internal combustion engine, wherein the transmittance is detected based on a detection value of the means and a detection value of the catalyst bed temperature detection means. 15. The sulfur poisoning detection means for detecting sulfur poisoning to the NOx occlusion reduction catalyst according to claim 14, wherein the deterioration degree detection means detects the NOx detected by the sulfur poisoning detection means. An exhaust gas purification catalyst reduction amount detection device for an internal combustion engine, wherein the degree of sulfur poisoning of the storage reduction catalyst is detected as the degree of deterioration of the NOx storage reduction catalyst. 16. The internal combustion engine according to claim 14 or 15, wherein the deterioration degree detecting means sets the deterioration degree of the NOx storage reduction catalyst according to a detection value of the catalyst bed temperature detecting means. Exhaust gas purification catalyst reduction amount detection device. 17. The method according to any one of claims 14 to 16,
N for detecting the NOx storage capacity of the NOx storage reduction catalyst
Ox storage capacity detection means is provided, and the deterioration degree detection means is configured to deteriorate the NOx storage reduction catalyst based on a detection value of the NOx storage capacity detection means and an unused NOx storage capacity of the NOx storage reduction catalyst. An exhaust gas purification catalyst reduction amount detection device for an internal combustion engine, which is characterized by detecting the degree. 18. An exhaust gas purification catalyst reduction amount detection device for an internal combustion engine according to claim 11, NOx amount detection means for determining an NOx amount in the exhaust gas based on an operating state of the internal combustion engine, and the exhaust gas. Exhaust purification management means for executing exhaust purification management based on the reduction amount of the NOx storage reduction catalyst determined by the purification catalyst reduction amount detection device and the NOx amount determined by the NOx amount detection means. An exhaust gas purification management device for an internal combustion engine, comprising: 19. The exhaust purification management means according to claim 18, wherein the reduction amount of the NOx storage reduction catalyst obtained by the exhaust purification catalyst reduction amount detection device and the NOx amount obtained by the NOx amount detection means. An exhaust gas purification management device for an internal combustion engine, wherein exhaust gas purification control is executed based on the NOx storage amount of the NOx storage reduction catalyst calculated by the balance calculation. 20. An exhaust gas purification catalyst reduction amount detection device for an internal combustion engine according to claim 11, NOx amount detection means for determining an NOx amount in the exhaust gas based on an operating state of the internal combustion engine, and the exhaust gas. NOx occlusion amount for calculating the NOx occlusion amount of the NOx occlusion reduction catalyst by calculating the balance between the reduction amount of the NOx occlusion reduction catalyst obtained by the purification catalyst reduction amount detection device and the NOx amount obtained by the NOx amount detection means. An exhaust gas purification catalyst NO for an internal combustion engine, comprising:
x Storage amount calculation device.