JP2013124631A - Exhaust emission control device for diesel engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust emission control device for a diesel engine, configured to estimate the amount of PM deposit more precisely.SOLUTION: The exhaust emission control device for a diesel engine has: an emission calculation means (51) for calculating the amount of PM discharged to an exhaust passage (3); and a continuous regeneration amount calculation means (52) for calculating the amount of PM continuously regenerated in a DPF (7). A PM deposit amount estimation means (50) is configured to estimate the amount of PM deposit in the DPF(7) from the difference between the PM emission calculated by the emission calculation means (51) and the PM regeneration amount calculated by the continuous regeneration amount calculation means (52). The continuous regeneration amount calculation means (52) is configured to calculate the amount of continuously regenerated PM by adding the amount of PM regenerated by oxygen contained in the exhaust gas to the amount of PM regenerated by nitrogen dioxide contained in the exhaust gas.

Description

  The present invention includes an oxidation catalyst (DOC) disposed in an exhaust passage, a diesel particulate filter (DPF) disposed downstream of the DOC and collecting exhaust particulates (PM) in exhaust gas, and the DPF. The present invention relates to an exhaust gas purification apparatus for a diesel engine, comprising PM accumulation amount estimation means for estimating the accumulated PM accumulation amount.

As an effective technique for removing PM contained in exhaust gas from a diesel engine, DPF is known.
The DPF is a PM collection device using a filter, and is a device that is installed in the exhaust passage, collects PM such as soot discharged from the engine, and removes it from the exhaust gas. A part of the PM collected by the DPF is combusted by high-temperature exhaust gas discharged from the operating engine (continuous regeneration), but the remaining PM is deposited on the filter of the DPF. If PM is excessively accumulated, engine output and fuel consumption are reduced due to increased exhaust pressure, and DPF is damaged due to abnormal combustion of PM. For this reason, in the DPF, it is necessary to perform forced regeneration at an appropriate timing for forcibly burning PM accumulated on the filter to regenerate the filter.

  In order to grasp an appropriate timing for performing the forced regeneration, it is necessary to accurately estimate the PM accumulation amount of the filter. If the amount of accumulated PM is underestimated, the forced regeneration timing will be delayed, resulting in a decrease in PM trapping capacity and engine output due to excessive PM accumulation, as well as a decrease in DPF due to excessive temperature rise during forced regeneration. Possible damage. On the other hand, if the PM accumulation amount is excessively evaluated, the frequency of forced regeneration increases, and problems such as deterioration in fuel consumption and oil dilution occur. Here, oil dilution raises the temperature of the DPF during forced regeneration, so that part of the fuel injected at a timing that does not contribute to in-cylinder combustion enters the oil pan through the cylinder liner, diluting the oil. Say that will be. When oil is diluted with fuel, the lubricity of the oil decreases. And if lubricity falls below a predetermined level, it may lead to engine damage.

  At this time, the amount of PM deposited on the DPF filter is estimated by sequentially integrating the subtraction value obtained by subtracting the PM regeneration amount from the PM discharge amount, as disclosed in, for example, Patent Document 1. At this time, the PM emission amount is calculated by a map using the engine speed and the fuel injection amount as input data. On the other hand, the PM regeneration amount is calculated by a map created in advance through experiments or the like based on measured values of various sensors such as a temperature sensor, a pressure sensor, and an air flow meter in addition to the engine speed and the fuel injection amount.

JP 2005-54632 A JP 2004-44457 A

  By the way, the catalyst supported on the DPF and the DOC is deteriorated by long-term use, so that the amount of PM regeneration described above also decreases with time. However, in Patent Document 1 described above, the deterioration of the catalyst is not considered at all when calculating the PM regeneration amount. For this reason, when the catalyst deteriorates due to long-term use, there is a problem that the PM regeneration amount is calculated to be larger than the actual amount, and the PM deposition amount is estimated too low.

  On the other hand, it is conceivable to calculate the PM regeneration amount with the catalyst deterioration expected in advance. However, in this case, the PM regeneration amount is calculated to be larger than the actual amount until the catalyst is deteriorated, and the PM deposition amount is excessively estimated.

  Patent Document 2 discloses a technique for correcting the PM regeneration amount when the DPF is exposed to a high temperature of a predetermined level or more in order to reflect the degree of deterioration of the DPF when calculating the PM regeneration amount. However, in this patent document 2, since the high temperature exposure time is accumulated by only one threshold (high temperature above a predetermined value) and the PM regeneration amount is corrected, the difference in the exposed temperature is not taken into consideration. That is, for example, when the threshold value is set to 600 ° C., even if it is exposed to a high temperature of 1200 ° C. for a predetermined time, the correction amount is the same as that when it is exposed to 600 ° C. for the same time. However, since the degree of catalyst deterioration inherently increases exponentially with respect to temperature, the method of Patent Document 2 cannot accurately reflect the degree of catalyst deterioration. Furthermore, the deterioration of the DOC catalyst is not considered at all in calculating the PM regeneration amount.

  In addition, during warm-up operation immediately after engine startup, there is a case where the exhaust gas is prematurely raised by changing the combustion conditions of the engine. In such a case, the PM discharged from the engine tends to increase. In the above-described map using the engine speed and the fuel injection amount as input data, there is a problem that the PM emission amount during the warm-up operation cannot be accurately calculated.

  The present invention is an invention made in view of such problems of the prior art, and by estimating the PM deposition amount with higher accuracy than before, the PM collection ability is reduced due to the underestimation of the PM deposition amount and the engine output is reduced. It is an object of the present invention to provide an exhaust emission control device for a diesel engine that can avoid problems such as a decrease in fuel consumption and problems such as deterioration in fuel consumption due to excessive estimation of the amount of accumulated PM and oil dilution.

The present invention has been invented in order to achieve the problems and objects in the prior art as described above,
An exhaust emission control device for a diesel engine according to the present invention includes:
An oxidation catalyst (DOC) disposed in the exhaust passage, a diesel particulate filter (DPF) disposed on the downstream side of the DOC and collecting exhaust particulates (PM) in the exhaust gas, and PM deposition deposited on the DPF In an exhaust emission control device for a diesel engine provided with a PM accumulation amount estimation means for estimating an amount,
A discharge amount calculating means for calculating a PM discharge amount discharged into the exhaust passage; and a continuous regeneration amount calculating means for calculating a PM regeneration amount continuously regenerated in the DPF, the PM accumulation amount estimating means, From the difference between the PM emission amount calculated by the emission amount calculating means and the PM regeneration amount calculated by the continuous regeneration amount calculating means, the PM accumulation amount in the DPF is estimated.
The continuous regeneration amount calculating means calculates the continuously regenerated PM regeneration amount by adding the PM regeneration amount by oxygen contained in the exhaust gas and the PM regeneration amount by nitrogen dioxide contained in the exhaust gas. Features.

  In the present invention, since the PM regeneration amount continuously regenerated by adding the PM regeneration amount by oxygen and the PM regeneration amount by nitrogen dioxide is calculated, the continuously regenerated PM regeneration amount can be accurately calculated. It is possible to estimate the PM deposition amount with higher accuracy than in the past.

  In the above invention, it is desirable that the continuous regeneration amount calculating means is configured to calculate the PM regeneration amount according to the degree of deterioration of the catalyst supported on the DPF and the DOC.

  In the present invention, since the PM regeneration amount is calculated according to the degree of deterioration of the catalyst supported on the DPF and the DOC, the above-described conventional technique in which only the degree of deterioration of the DPF is considered. Compared with, it is possible to estimate the PM deposition amount with high accuracy.

  In the above invention, the PM regeneration amount by oxygen and the PM regeneration amount by nitrogen dioxide are each calculated according to the degree of deterioration of the catalyst supported on the DPF.

  At this time, in the above invention, the continuous regeneration amount calculating means is preferably configured to calculate the PM regeneration amount by the nitrogen dioxide according to the degree of deterioration of the catalyst supported on the DOC. .

  With this configuration, the degree of deterioration of the catalyst supported on the DPF and the DOC can be reflected in the calculation of the PM regeneration amount, so that the PM deposition amount can be estimated with higher accuracy than in the past. it can.

  In the above invention, the degree of deterioration of the catalyst carried on the DPF and the DOC is determined from the relationship between the operation time of the diesel engine and the average temperature of the DPF and the DOC during the operation time of the diesel engine, respectively. It is desirable to be configured to be calculated.

  Thus, in the present invention, the degree of catalyst deterioration is calculated from the relationship between the operation time of the diesel engine and the average temperature of the DPF and DOC. Therefore, the degree of deterioration of the catalyst can be accurately grasped compared to the conventional case in which the high temperature exposure time is calculated based on only one threshold (high temperature above a predetermined value) and this is regarded as the degree of deterioration of the catalyst. The amount of deposition can be estimated with higher accuracy.

  Further, in the above invention, it is desirable that the discharge amount calculating means is configured to calculate a PM discharge amount according to an engine coolant temperature.

  If configured in this way, the PM emission amount corresponding to the engine coolant temperature is calculated in the emission amount calculation means, and therefore the PM emission amount during warm-up operation immediately after engine startup is accurately calculated. Can do.

  According to the present invention, since the amount of accumulated PM can be estimated with higher accuracy than in the past, problems such as a decrease in PM collection ability and a decrease in engine output due to an underestimation of the amount of accumulated PM, and the amount of accumulated PM It is possible to provide an exhaust emission control device for a diesel engine that can avoid problems such as deterioration in fuel consumption and oil dilution due to overestimation.

1 is an overall configuration diagram of a diesel engine equipped with an exhaust purification device of the present invention. It is the block diagram which showed the discharge | emission amount calculation means of this invention. It is the block diagram which showed the continuous reproduction amount calculation means of this invention. It is the graph which showed the relationship between the deterioration degree (K / K0) of a catalyst, and engine operating time. It is the block diagram which showed the modification of the discharge amount calculation means of this invention.

Hereinafter, embodiments of the present invention will be described in more detail based on the drawings.
However, the scope of the present invention is not limited to the following embodiments. The dimensions, materials, shapes, relative arrangements, and the like of the components described in the following embodiments are merely illustrative examples and are not intended to limit the scope of the present invention only unless otherwise specified.

  FIG. 1 is an overall configuration diagram of a diesel engine equipped with an exhaust purification device of the present invention. First, the overall configuration of the exhaust emission control device for a diesel engine according to the present invention will be described with reference to FIG.

As shown in FIG. 1, an exhaust passage 3 is connected to the downstream side of the engine 1 of the diesel engine. The exhaust passage 3 is provided with an exhaust gas aftertreatment device 9 including a DOC (oxidation catalyst) 5 and a DPF 7 on the downstream side of the DOC 5. The DOC 5 has a function of oxidizing and removing hydrocarbons (HC) and carbon monoxide (CO) in the exhaust gas and oxidizing nitrogen monoxide (NO) in the exhaust gas to generate nitrogen dioxide (NO ₂ ). As described above, the DPF 7 is a device that collects PM such as soot contained in the exhaust gas with a filter and removes it from the exhaust gas.

  An air supply passage 13 is connected to the upstream side of the engine 1. An exhaust turbocharger 11 is provided between the air supply passage 13 and the exhaust passage 3. The exhaust turbocharger 11 has an exhaust turbine 11b disposed in the exhaust passage 3 and a compressor 11a disposed in the intake passage 13, and the compressor 11a is coaxially driven by the exhaust turbine 11b. It has become so. In addition, an intercooler 15 and an air supply throttle valve 17 are provided in the air supply passage 13. The air discharged from the compressor 11 a is cooled by the intercooler 15, then the supply air flow rate is controlled by the supply air throttle valve 17, and flows into the combustion chamber in each cylinder of the engine 1. .

  Further, the engine 1 is provided with a common rail fuel injection device 18 that controls the fuel injection timing and the injection amount and injects the fuel into the combustion chamber in the cylinder. The common rail fuel injection device 18 is controlled by a control signal transmitted from the control ECU 19 such that a predetermined amount of fuel is supplied from the common rail 18a to the fuel injection valve 18b at a predetermined injection timing.

  The exhaust gas discharged from the engine 1 passes through the exhaust passage 3 and drives the exhaust turbine 11b described above to drive the compressor 11a coaxially. Then, after passing through the exhaust passage 3, it flows to the DOC 5 and the DPF 7 of the exhaust gas aftertreatment device 9 described above. An air flow meter 31 that detects the flow rate of air flowing into the compressor 11a is disposed in the air supply passage 13. A signal related to the supply air flow rate measured by the air flow meter 31 is input to the control ECU 19.

  A DOC inlet temperature sensor 35, a DPF inlet pressure sensor 36, a DPF inlet temperature sensor 37, a DPF differential pressure sensor 38, and a DPF outlet temperature sensor 39 are disposed in the exhaust passage 3. Signals relating to the DOC inlet temperature, the DPF inlet temperature, the DPF outlet temperature, and the like measured by these sensors are input to the control ECU 19.

  The control ECU 19 calculates the engine speed and the fuel injection amount based on input signals from various sensors (not shown) such as a crank sensor, a cam sensor, an accelerator sensor, a throttle sensor, and a coolant temperature sensor. Yes.

  The control ECU 19 includes a microcomputer including a central processing unit (CPU), a random access memory (RAM), a read only memory (ROM), an I / O interface, and the like. Various signals from the above-described sensors are input to the CPU via the I / O interface. The CPU is configured to execute various controls according to a control program stored in the ROM. As shown in FIG. 1, the control ECU 19 constitutes a PM accumulation amount estimation means 50, an emission amount calculation means 51, and a continuous regeneration amount calculation means 52 of the present invention.

  The emission amount calculation means 51 calculates the PM amount (PM emission amount) contained in the exhaust gas discharged from the engine 1. The calculation of the PM emission amount in the emission amount calculation means 51 is performed by a PM emission amount map 55 using the engine speed and the fuel injection amount as input data, as shown in FIG. This PM emission amount map 55 is created by conducting an experiment or the like, and is stored in advance in the ROM of the control ECU 19. Here, in order to estimate the increase in the PM emission amount during the transient operation, it is possible to determine the transient state and correct the increase in the emission amount.

The continuous regeneration amount calculating means 52 calculates the continuous regeneration amount, that is, the PM amount (PM regeneration amount) combusted by the high-temperature exhaust gas discharged from the engine 1 in the normal operation state, not during the forced regeneration. As shown in FIG. 3, the PM regeneration amount is calculated by calculating the PM regeneration amount by oxygen (O ₂ ) and the PM regeneration amount by nitrogen dioxide (NO ₂ ), and adding them together. Note that the forced regeneration amount can be calculated by the same configuration as the continuous regeneration amount calculating means 52.

The amount of PM regeneration due to oxygen is calculated by an O ₂ regeneration amount map 56 using DPF temperature, oxygen concentration, and the degree of DPF deterioration described later as input data. At this time, the oxygen concentration can be measured by an O ₂ sensor or the like, but in this embodiment, the oxygen concentration is calculated by the control ECU 19 based on the pressure and temperature of the exhaust gas, the engine speed, the fuel injection amount, and the like. Yes.

The amount of PM regeneration due to nitrogen dioxide is calculated by a NO ₂ regeneration amount map 57 using DPF temperature, nitrogen dioxide concentration, and DPF deterioration degree described later as input data. The nitrogen dioxide concentration is calculated by multiplying the NO _x amount by the abundance ratio of NO ₂ . The ratio of NO ₂ is the exhaust gas flow rate, DOC temperature, DPF temperature and later to DOC degradation degree is calculated by NO ₂ ratio map 58 to input data DPF deterioration degree. At this time, the exhaust gas flow rate is calculated from the supply air flow rate measured by the air flow meter 31 described above. Further, the NO _X concentration is calculated from a NO _X emission amount map 59 using the engine speed and the fuel injection amount as input data. The above-mentioned DOC temperature and DPF temperature are theoretically desirably measured by directly measuring the temperatures of the DOC base material and the DPF base material. However, by substituting the DPF inlet / outlet average temperature and the DOC inlet / outlet average temperature, sufficient calculation accuracy can be secured and the DOC temperature and DPF temperature can be grasped with a simple configuration.

The O ₂ regeneration amount map 56, the NO ₂ regeneration amount map 57, the NO ₂ ratio map 58, and the NO _X emission amount map 59 described above are created by performing experiments and the like, and are stored in the ROM of the control ECU 19 in advance. . The PM regeneration amount is calculated based on the signals transmitted from various sensors. Further, the above-described NO ₂ ratio map 58 can be substituted by a map (NO ₂ conversion rate map) for calculating the conversion rate from NO to NO ₂ .

  Then, the PM accumulation amount estimation means 50 integrates the difference between the PM emission amount calculated by the emission amount calculation means 51 and the PM regeneration amount calculated by the continuous regeneration amount calculation means 52, thereby obtaining the PM accumulation amount. Calculated (estimated).

<Calculation of DPF and DOC degradation>
Next, a method for calculating the DPF deterioration level and the DOC deterioration level will be described below. The DPF deterioration degree and the DOC deterioration degree here mean the deterioration degree of the catalyst supported on the DPF and the DOC, respectively, and are expressed as shown in the following formulas (1) and (2).
Degree of DPF degradation = K _DPF / K0 _DPF (1)
Degree of DOC degradation = K _DOC / K0 _DOC (2)
(K0 _DPF : Initial reaction rate constant of catalyst supported on DPF, K _DPF : Reaction rate constant after deterioration of catalyst supported on DPF, K0 _DOC : Catalyst rate of catalyst supported on DOC (Initial reaction rate constant, K _DOC : Reaction rate constant after deterioration of the catalyst supported on DOC.)

In the present invention, the DPF deterioration degree and the DOC deterioration degree are respectively calculated from the relationship between the operation time of the diesel engine and the average temperatures of the DPF and DOC during the operation time of the diesel engine.

  Specifically, for example, as shown in FIG. 4 (a), a graph including the degree of deterioration (K / K0) and the engine operating time is prepared in advance for each predetermined temperature by experiments or the like. It is stored in the ROM of the ECU 19. Based on the graph of FIG. 4 (a), the deterioration degree (K / K0) as shown in FIG. 4 (b) is calculated from the engine operation time and the average temperature of the DPF and DOC during the engine operation time. Estimate changing behavior. For example, as shown in FIG. 4C, the degree of deterioration (K / K0) when the temperature changes with the operating time is shown on the basis of a graph corresponding to the temperature at a certain operating time a to d. It changes as shown in 4 (b). That is, the degree of deterioration (K / K0) changes based on a graph corresponding to 600 ° C. for the operation time a, 700 ° C. for the operation time b, and 800 ° C. for the operation time c. In the operation time d, since the degree of deterioration (K / K0) is already below the minimum value of 600 ° C., the behavior of the degree of deterioration (K / K0) does not change.

Further, for example, a relational expression for obtaining K as shown in the following formulas (3) and (4) is created in advance by experiments or the like and stored in the ROM of the control ECU 19. Then, the degree of deterioration (K / K0) is calculated based on the following formulas (3) and (4) from the operating time (t) and the average temperature (T) of the DPF and DOC during the engine operating time. be able to.
-DK / dt = ζK ⁿ (3)
ζ = φexp (−E / RT) (4)
(Here, n: multiplier of reaction rate constant K, E: activation energy, R: gas constant, T: absolute temperature, φ: deterioration constant.)

  The above-described graph of FIG. 4 and the relational expressions (3) and (4) vary depending on the type of catalyst and the like. Therefore, the above graph and / or the above relational expression are created for each catalyst supported on the DPF and the DOC and held in the control ECU 19.

By inputting the degree of DPF deterioration (K _DPF / K0 _DPF ) calculated in this way into the O ₂ regeneration amount map 56 in FIG. 3 described above, O ₂ corresponding to the degree of deterioration of the catalyst supported on the DPF is obtained. The PM regeneration amount is calculated. Similarly, by inputting the DPF deterioration degree (K _DPF / K0 _DPF ) to the NO ₂ regeneration amount map 57, the PM regeneration amount by NO ₂ corresponding to the deterioration degree of the catalyst carried on the DPF is calculated. .

Further, the NO ₂ ratio is calculated by inputting the DOC deterioration degree (K _DOC / K0 _DOC ) calculated in the same manner to the NO ₂ ratio map 58 in FIG. At this time, the NO ₂ ratio map 58 is composed of, for example, a plurality of map groups created corresponding to different DOC deterioration degrees, and the NO ₂ ratio is based on the map corresponding to the input DOC deterioration degrees. Is calculated. Moreover, you may calculate so that it may interpolate between maps. Then, the NO ₂ ratio calculated by the NO ₂ ratio map 58, that NO ₂ concentration that is input to the NO ₂ regeneration amount map 57 is calculated, in accordance with the degree of deterioration of the catalyst carried on the DOC NO ₂ is calculated. Further, according to the study by the present inventors, it has been confirmed that the above-mentioned NO ₂ ratio is also affected by the presence of NO ₂ produced by DPF. Therefore, in the present invention, the NO ₂ ratio map 58 using the DPF deterioration degree (K _DPF / K0 _DPF ) as input data instead of or in combination with the above-described DOC deterioration degree (K _DOC / K0 _DOC ) May be used to calculate the NO ₂ ratio.

  As described above, in the present invention, the PM regeneration amount is calculated in accordance with the degree of deterioration of the catalyst supported on the DPF 7 and the DOC 5, and therefore, the amount of accumulated PM compared to the conventional technique in which only the degree of deterioration of the DPF is considered. Can be estimated with high accuracy.

  Further, as described above, the degree of deterioration (K / K0) of the catalyst carried on the DPF 7 and the DOC 5 is calculated from the relationship between the engine operating time and the average temperature of the DPF and DOC during the engine operating time. Since the temperature history of the catalyst can be appropriately reflected on the degree of deterioration of the catalyst, the PM deposition amount can be estimated with higher accuracy than in the past.

  As mentioned above, although the preferable form of this invention was demonstrated, this invention is not limited to said form, A various change in the range which does not deviate from the objective of this invention is possible.

  For example, in the above-described embodiment, the PM emission amount from the engine is calculated from the PM emission amount map 55 using the engine speed and the fuel injection amount as input data. However, for example, as shown in FIG. 5A, the PM emission amount may be calculated by multiplying the value calculated from the map 55 by a correction coefficient corresponding to the engine coolant temperature. Further, as shown in FIG. 5B, when the cooling water temperature is equal to or lower than a predetermined temperature (for example, less than 60 ° C.) by the map switching means 60 that switches the PM emission amount map to be applied according to the cooling water temperature. Instead of the normal PM emission amount map 55, a low temperature PM emission amount map 55 ′ may be applied. The low temperature PM emission amount map 55 ′ is composed of, for example, a plurality of map groups created corresponding to different cooling water temperatures, and the PM emission amount is based on the map corresponding to the inputted cooling water temperature. It is calculated. Moreover, you may calculate so that it may interpolate between maps.

  If the present invention is configured in this way, the emission amount calculating means 51 can calculate the PM emission amount according to the engine coolant temperature, and therefore, for example, the PM emission amount during the warm-up operation immediately after the engine is started is also obtained. It can be calculated with high accuracy.

  ADVANTAGE OF THE INVENTION According to this invention, it can use suitably as an exhaust gas purification apparatus of the diesel engine which can estimate PM deposit amount deposited on DPF with high precision over a long period of time.

1 Engine 3 Exhaust passage 5 DOC
7 DPF
9 Exhaust gas aftertreatment device 11 Exhaust turbocharger 11a Compressor 11b Exhaust turbine 13 Supply passage 15 Intercooler 17 Supply throttle valve 18 Common rail fuel injection control device 18a Common rail 18b Fuel injection valve 31 Air flow meter 35 DOC inlet temperature sensor 36 DPF Inlet pressure sensor 37 DPF inlet temperature sensor 38 DPF differential pressure sensor 39 DPF outlet temperature sensor 50 PM accumulation amount estimation means 51 Discharge amount calculation means 52 Continuous regeneration amount calculation means 55 PM emission amount map 56 O ₂ regeneration amount map 57 NO ₂ regeneration Amount map 58 NO ₂ ratio map 59 NO _X emission map 60 Map switching means

Claims (6)

An oxidation catalyst (DOC) disposed in the exhaust passage, a diesel particulate filter (DPF) disposed on the downstream side of the DOC and collecting exhaust particulates (PM) in the exhaust gas, and PM deposition deposited on the DPF In an exhaust emission control device for a diesel engine provided with a PM accumulation amount estimation means for estimating an amount,
A discharge amount calculating means for calculating a PM discharge amount discharged into the exhaust passage; and a continuous regeneration amount calculating means for calculating a PM regeneration amount continuously regenerated in the DPF, the PM accumulation amount estimating means, From the difference between the PM emission amount calculated by the emission amount calculating means and the PM regeneration amount calculated by the continuous regeneration amount calculating means, the PM accumulation amount in the DPF is estimated.
The continuous regeneration amount calculating means calculates the continuously regenerated PM regeneration amount by adding the PM regeneration amount by oxygen contained in the exhaust gas and the PM regeneration amount by nitrogen dioxide contained in the exhaust gas. Diesel engine exhaust gas purification device.   The said continuous regeneration amount calculation means is comprised so that the said PM regeneration amount may be calculated according to the deterioration degree of the catalyst carry | supported by the said DPF and the said DOC. Diesel engine exhaust purification system.   The continuous regeneration amount calculating means is configured such that each of the PM regeneration amount by oxygen and the PM regeneration amount by nitrogen dioxide is calculated according to the degree of deterioration of the catalyst supported on the DPF. The exhaust emission control device for a diesel engine according to claim 2, wherein:   The said continuous regeneration amount calculation means is comprised so that PM regeneration amount by the said nitrogen dioxide may be calculated according to the deterioration degree of the catalyst carry | supported by the said DOC. 2. An exhaust emission control device for a diesel engine according to 1.   The degree of deterioration of the catalyst supported on the DPF and the DOC is calculated from the relationship between the operation time of the diesel engine and the average temperature of the DPF and the DOC during the operation time of the diesel engine, respectively. The exhaust emission control device for a diesel engine according to any one of claims 2 to 4, wherein the exhaust gas purification device is configured. The exhaust emission control device for a diesel engine according to any one of claims 1 to 5, wherein the emission amount calculating means is configured to calculate a PM emission amount in accordance with an engine coolant temperature.

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