JP2003155919A - Exhaust emission control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust emission control device which estimates the deposition of the particulate in a state close to the actual state. SOLUTION: In the exhaust emission control device equipped with a catalyst regeneration type particulate filter 6 in the middle of an exhaust pipe 4 with the exhaust gas 3 distributed therein, a control device 11 comprises a generation estimating means to estimate the generation of the particulate based on the operational state of a diesel engine 1 (an internal combustion engine), a regeneration area determining means to determine whether or not the treatment quantity of the particulate exceeds the trapping quantity thereof in the present operational state, and a deposition estimating means in which the generation of the particulate estimated by the generation estimating means while the present operational state is in a regeneration area by the regeneration area determining means is subtracted, and only the generation of the particulate in the non- regenerated area is integrated to obtain the deposition in the particulate filter 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust emission control device.

[0002]

2. Description of the Related Art Particulate Matter (Particulate Matter) emitted from a diesel engine is
Soot composed of carbonaceous matter and SO composed of high boiling hydrocarbon components
It is composed of F component (Soluble Organic Fraction) as a main component and further contains a trace amount of sulfate (mist-like sulfuric acid component), but as a measure for reducing this type of particulates, exhaust gas is used. It has been conventionally practiced to equip a particulate filter in the middle of an exhaust pipe through which gas flows.

This type of particulate filter has a porous honeycomb structure made of a ceramic such as cordierite, and the inlets of the flow passages partitioned in a grid pattern are alternately plugged, and the inlets are plugged. The outlets of the non-flow passages are configured to be plugged so that only the exhaust gas that has permeated the porous thin wall defining each flow passage is discharged to the downstream side.

Since the particulates in the exhaust gas are collected and deposited on the inner surface of the porous thin wall, the particulates are appropriately burned and removed before the exhaust resistance increases due to clogging. It is necessary to regenerate the particulate filter, but in normal diesel engine operating conditions, there are few opportunities to obtain a high exhaust gas temperature that allows particulates to self-combust.
For example, a catalyst regeneration type particulate filter in which an oxidation catalyst formed by adding an appropriate amount of a rare earth element such as cerium to alumina supported by platinum is integrally supported is being put into practical use.

That is, if such a catalyst regeneration type particulate filter is adopted, the oxidation reaction of the collected particulates is promoted to lower the ignition temperature, and the particulates are burned and removed even at an exhaust temperature lower than the conventional one. It becomes possible to do it.

However, even if such a catalyst regeneration type particulate filter is adopted, the trapped amount exceeds the treated amount of particulates in an operating region where the exhaust temperature is low, and thus If the operating condition at such a low exhaust temperature continues, there is a risk that the particulate filter will not regenerate favorably and the particulate filter may fall into an over-captured state. It is considered that fuel is added to the exhaust gas on the upstream side of the particulate filter to perform forced regeneration of the particulate filter.

That is, if the fuel is added on the upstream side of the particulate filter, the added fuel undergoes an oxidation reaction on the oxidation catalyst of the particulate filter, and the heat of reaction raises the catalyst bed temperature to raise the particulates. It is burned out and the particulate filter is regenerated.

[0008]

However, in the prior art, the generation amount of particulates is estimated based on the rotational speed of the diesel engine and the load (fuel injection amount),
It is considered to integrate the estimated generation amount of particulates and perform forced regeneration of the particulate filter when the integrated value of the generated amount reaches a predetermined upper limit value. The amount of particulates accumulated inside is the amount generated by subtracting the amount processed by combustion from the amount generated, so simply adding up the amount of particulates generated is more than the actual amount accumulated. As a result, the timing of forced regeneration will be decided based on the integrated value of the generated amount, and forced regeneration will have to be performed at unnecessarily short intervals.
There is a problem that the energy cost associated with the forced regeneration (fuel consumption when the forced regeneration is performed by adding fuel, electric power cost in the case of an electric heater) increases.

The present invention has been made in view of the above situation, and provides an exhaust gas purification device capable of estimating the accumulated amount of particulates that is close to the actual state, so that the particulates can be collected at appropriate intervals. The purpose is to be able to determine the time of forced regeneration of the filter.

[0010]

DISCLOSURE OF THE INVENTION The present invention is an exhaust gas purification apparatus equipped with a catalyst regeneration type particulate filter in the middle of an exhaust pipe through which exhaust gas flows. A generation amount estimation means for estimating the generation amount, a reproduction area determination means for determining whether or not the processing amount of particulates in the current operation state is in a reproduction area exceeding the collection amount, and the reproduction area determination means. While the current operating state is determined to be in the regeneration area, the generation amount of particulates estimated by the generation amount estimating means is excluded, and only the generation amount of particulates in the non-regeneration area is integrated to improve the performance. And a means for estimating the amount of deposition in the curate filter.

[0011] Thus, in this case, it is considered that there is almost no accumulation of new particulates in the regeneration region where the amount of particulates processed exceeds the trapping amount, and in the non-regeneration region. By accumulating only the generation amount of particulates to obtain the accumulation amount in the particulate filter, the estimation of the accumulation amount of particulates close to the actual state can be realized.

Moreover, the estimated amount of particulate matter does not take into consideration the amount of burning of particulate matter already deposited in the regeneration region, so that the value of the particulate matter is close to the actual state. Since the accumulated amount will be accumulated and estimated, it will not fall below the actual accumulated amount, so the particulate filter that has already fallen into the over-collection state has a small amount of accumulated particulate. It is possible to avoid such a risk that it will be judged.

Further, the present invention is an exhaust gas purification device equipped with a catalyst regeneration type particulate filter in the middle of an exhaust pipe through which exhaust gas flows, and measures the traveling distance as a substitute value of the amount of particulate generation. The running distance measuring means, a reproduction area determining means for determining whether or not the processing amount of particulates in the current operation state is in a reproduction area exceeding the collection amount, and the current operation state by the reproduction area determining means. Deposition that excludes the mileage measured by the mileage measuring means while it is determined to be in the regeneration area and integrates only the mileage in the non-regeneration area to be a guide for the amount of accumulation in the particulate filter. It is also characterized by comprising a quantity estimating means.

Thus, in this way, it is considered that there is almost no accumulation of new particulates in the regeneration region where the amount of particulates processed exceeds the amount collected, and the amount of accumulated particulates is surely achieved. By accumulating only the traveling distance in the increasing non-regeneration area and using it as a guideline for the accumulated amount in the particulate filter, the accumulated traveling distance corresponding to the actual increase in the accumulated amount can be realized.

In addition, in the integration of the traveling distance, since the subtraction of the traveling distance corresponding to the combustion of the particulates already accumulated in the regeneration area is not considered, there is almost no new accumulation of particulates. While the mileage is properly excluded, the accumulated mileage is estimated so that the accumulated amount of particulates accumulates, and at least the actual amount accumulated is estimated. This prevents excessive subtraction of the mileage, which may cause the particulate filter that has already fallen into the over-capture state to judge that the accumulated amount of particulates is small because the mileage is still insufficient. Fear is avoided.

Further, in any of the above-mentioned regeneration region determining means of the exhaust gas purification device, the exhaust gas temperature at which the treated amount of particulates and the trapped amount are substantially equal to each other is set as a threshold value, and the exhaust gas temperature measured is a predetermined time or more. It is possible to make a judgment of the reproduction area when the time is exceeded.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

1 to 5 show an example of an embodiment for carrying out the present invention. In the exhaust gas purification apparatus of this embodiment, as shown in FIG. 1, from a diesel engine 1 (internal combustion engine) of an automobile to an exhaust manifold. An example is shown in which a catalyst regeneration type particulate filter 6 having an oxidation catalyst integrally supported therein is housed in a muffler 5 of an exhaust pipe 4 in which exhaust gas 3 discharged via 2 flows. The filter case 7 holding the particulate filter 6 forms an outer cylinder of the muffler 5.

That is, the front and rear inlet pipes 8 and outlet pipes 9 are provided.
A particulate filter 6 as shown in an enlarged scale in FIG. 2 is housed inside a filter case 7 provided with, and this particulate filter 6 has a porous honeycomb structure made of ceramics and has a lattice structure. The inlets of the respective flow paths 6a which are partitioned in a circular pattern are alternately plugged, and for the flow paths 6a whose inlets are not plugged, the outlets thereof are plugged, and the respective flow paths 6a are partitioned. Only the exhaust gas 3 that has permeated through the porous thin wall 6b is discharged to the downstream side.

The outlet pipe 9 of the filter case 7
Includes a temperature sensor 1 for measuring the temperature of the exhaust gas 3.
0, and the detection signal 10a of the temperature sensor 10 is an engine control computer (ECU: Electronic Control).
The fuel injection timing and the fuel injection timing toward the fuel injection device 12 that injects fuel into each cylinder of the diesel engine 1 are input to the control device 11 that forms a unit). A fuel injection signal 12a that commands the amount is output.

Here, the fuel injection device 12 is composed of a plurality of injectors (not shown) provided for each cylinder, and the solenoid valves of these injectors are appropriately opened and controlled by the fuel injection signal 12a. The fuel injection timing (injection start timing and injection end timing) and the injection amount (valve opening time) are controlled appropriately.

The driver's seat accelerator (not shown)
An accelerator sensor 13 (load sensor) for detecting the accelerator opening as a load of the diesel engine 1 is provided, and a rotation sensor 14 for detecting the rotation speed is provided at an appropriate position of the diesel engine 1, The accelerator opening signal 13a and the rotation speed signal 14a from the accelerator sensor 13 and the rotation sensor 14 are also input to the control device 11.

In the control device 11, the normal mode fuel injection signal 12a is determined based on the accelerator opening signal 13a and the rotation speed signal 14a, while the particulate filter 6 is forcibly regenerated. At this time, the normal mode is switched to the forced regeneration mode, and the main fuel injection is performed near the compression top dead center (crank angle 0 °), and then the post injection is performed later than the compression top dead center and at a timing that does not ignite. The signal 12a is to be determined.

That is, when the post injection is performed following the main injection at a timing that is later than the compression top dead center and does not ignite, unburned fuel (mainly HC: hydrocarbons) in the exhaust gas 3 due to the post injection. As a result, the unburned fuel undergoes an oxidation reaction on the oxidation catalyst on the surface of the particulate filter 6 and the catalyst bed temperature rises due to the heat of reaction to cause the particulates in the particulate filter 6 to spontaneously burn. Will be done.

Here, the switching from the normal mode to the forced regeneration mode in the control device 11 described above estimates the accumulation amount in the particulate filter 6 based on the operating state of the diesel engine 1, as will be described in detail below. The mode may be switched when the estimated deposition amount exceeds a predetermined upper limit value.

That is, in the present embodiment, the generation amount estimating means for estimating the generation amount of particulates based on the operating state of the diesel engine 1 and the processing amount of particulates for the current operating state exceed the collection amount. A regeneration region determining means for determining whether or not it is in a regeneration region, and a particulate matter estimated by the generation amount estimating means while the current operating state is determined to be in the regeneration region by the regeneration region determining means. The control device 11 has all the deposition amount estimation means that excludes the generation amount and integrates only the generation amount of the particulates in the non-regeneration area to obtain the deposition amount in the particulate filter 6. The estimation can be performed.

In short, each of the control block groups incorporated in the control device 11 as shown in the flow charts of FIGS. 3 and 4 constitutes the above-mentioned generation amount estimating means, regeneration area determining means, and accumulation amount estimating means, respectively. More specifically, the generation amount estimating means in steps S1 to S4 in FIG. 3 shows the reproduction area in steps S11 to S14 in FIG. 4 showing step S5 in FIG. 3 in detail. As the determining means, the deposit amount estimating means is configured by steps S6 and S7 in FIG. 3, respectively.

The control procedure will now be described with reference to the flow charts of FIGS. 3 and 4. In the flow chart of FIG. 3, the rotation speed of the diesel engine 1 is extracted based on the rotation speed signal 14a from the rotation sensor 14 in step S1. On the other hand, in step S2, the injection amount of the fuel that is known when the fuel injection signal 12a is determined based on the accelerator opening signal 13a from the accelerator sensor 13 is extracted, and the generation of particulates due to the rotational speed and the injection amount. The amount of particulate generation based on the current operating state of the diesel engine 1 is estimated in step S3 from the amount map (map in the engine steady state).

On the other hand, in step S4, various conditions such as the engine water temperature, the atmospheric temperature, the atmospheric pressure, the pressure loss increase due to the increase in the accumulated amount, the transient state (acceleration), and the like which influence the generation amount of particulates are considered. The calculated correction coefficient is calculated, and this correction coefficient is calculated in the previous step S3.
A value obtained by multiplying the generation amount map value estimated in step S3 is guided to step S5 as the generation amount (correction map value) of particulates.

For the transient state (acceleration), the rate of increase of the fuel injection amount per unit time may be monitored.

Then, in step S5, it is determined whether or not the processing amount of the particulates in the current operating state is in the regeneration region exceeding the collection amount, and more specifically, When the temperature measured by the temperature sensor 10 exceeds the threshold value for a predetermined time or more, with the exhaust gas temperature at which the treated amount of particulates and the trapped amount are substantially equal to each other as a threshold value, it is determined that the particulate filter 6 is in the regeneration state. Has become.

That is, in the map of the rotational speed and the load of the diesel engine 1 as shown in FIG. 5, in the operating region of the shaded portion above the curve A, the regeneration region in which the amount of particulates processed exceeds the trapped amount On the other hand, on the other hand, in the operating area below the non-shaded curve A, there is a non-regeneration area in which the amount of particulates processed falls below the collection amount. The exhaust temperature (exhaust temperature at the outlet of the particulate filter 6) in an operating state on the curve A forming the boundary line with is sampled and averaged, and is set as a threshold value for each rotation speed measured by the rotation sensor 14. The threshold value is changed to and the exhaust gas temperature measured by the temperature sensor 10 is compared.

However, the curve A which forms the boundary line between the regenerated region and the non-regenerated region is approximately similar to the uniform exhaust temperature line B of about 320 ° C., and the uniform exhaust temperature line B is
Is a condition higher than the curve A (a temperature condition higher than the exhaust temperature in the operating state on the curve A), so that the temperature of the equal exhaust temperature line B is set as a constant threshold to simplify the control system. It is also possible to plan.

Now, step S5 in FIG. 3 will be described in more detail with reference to the flowchart of FIG.
In 11, the exhaust gas temperature measured by the temperature sensor 10 is compared with the exhaust gas temperature threshold value determined based on the number of revolutions. Unless the actually measured exhaust gas temperature is equal to or higher than the threshold value, this step S11 is performed. When the measured exhaust gas temperature is equal to or higher than the threshold value, the state is continued for T seconds, and then the process proceeds to step S12 and the current value is determined. It is determined that the driving state is in the regeneration area.

After the determination of the regeneration region in step S12, a predetermined hysteresis amount is subtracted from the exhaust gas temperature measured by the temperature sensor 10 and the exhaust gas temperature threshold value determined based on the number of revolutions in step S13. The value is compared with the value, and the determination in step S13 is repeated for the new input value unless the actually measured exhaust temperature falls below a value obtained by subtracting a predetermined hysteresis amount from the threshold value. Therefore, when the actually measured exhaust gas temperature falls below a value obtained by subtracting a predetermined hysteresis amount from the threshold value, the process proceeds to step S14, and the determination of the regeneration region in the previous step S12 is cancelled. .

The value obtained by subtracting a predetermined amount of hysteresis from the exhaust temperature threshold value is used in the determination in step S13 because the regeneration region is frequently determined and released due to slight fluctuations in the actually measured exhaust temperature. This is to avoid a situation in which it is lost.

If it is determined in step S5 in FIG. 3 that the current operating state is in the regeneration area, the process proceeds to step S6 and the previous value is left unchanged without adding the current particulate generation amount. On the other hand, the total accumulated amount is set, and on the other hand, only when it is not determined in step S5 in FIG. 3 that the current operating state is in the regeneration region, the process proceeds to step S7, and the amount of particulates generated this time (correction map value ) Is added to the previous value to obtain the total accumulated amount.

Further, when the execution of the forced regeneration is confirmed in step S8, the particulate deposition amount calculated in step S6 or step S7 proceeds to step S9 and is reset to zero. But step S8
If execution of forced regeneration is not confirmed in step S10, the process proceeds to step S10 and the same estimation of the deposition amount is repeated from the beginning while the deposition amount is maintained.

When the exhaust purification device is operated by the control device 11 as described above, it is assumed that there is almost no accumulation of new particulates in the regeneration region where the amount of particulates processed exceeds the amount collected. Considering this, as shown in FIG. 6, by estimating only the generation amount of particulates in the non-regeneration area to obtain the accumulated amount in the particulate filter 6, it is possible to estimate the accumulated amount of particulates close to the actual state. Will be realized.

Moreover, since the estimated amount of particulates accumulated does not take into consideration the amount of burning of particulates already deposited in the regeneration region, the amount of particulates is close to the actual state. Since the accumulated amount will be accumulated and estimated, and at least the actual accumulated amount will not be reduced, the particulate filter 6 already in the over-captured state will have the accumulated accumulated amount of particulates. It is possible to avoid the risk that the number is small.

Therefore, according to the above-mentioned embodiment, it is possible to realize the estimation of the particulate accumulation amount close to the actual state, and based on this, the timing of the forced regeneration of the particulate filter 6 is determined at an appropriate interval. Therefore, the interval of forced regeneration can be made longer than before to reduce the energy cost associated with forced regeneration, and the deposition amount of particulates can be estimated so that it does not fall below the actual deposition amount. By doing so, safety can be secured.

In the above-described embodiment, the accumulated amount of particulates in the particulate filter 6 is estimated, but the travel distance is used as a substitute value for the accumulated amount of particulates. There may be a case where the interval of forced regeneration is decided by.

That is, as shown by the chain double-dashed line in FIG. 1, the control device 11 is configured to input the travel distance signal 15a from the distance meter 15, while the travel distance is used as a substitute value for the amount of particulate generation. Mileage measuring means for measuring, a reproduction area determining means for determining whether or not the processing amount of particulates in the current operating state is in a reproduction area exceeding the collection amount, and the reproduction area determining means for determining the current While the driving state is determined to be in the regeneration area, the traveling distance measured by the traveling distance measuring means is excluded, and only the traveling distance in the non-regeneration area is integrated to determine the accumulation amount in the particulate filter 6. It is also possible for the control device 11 to have all of the accumulated amount estimation means as a guide.

In short, each of the control block groups incorporated in the control device 11 as shown in the flow chart of FIG. 7 constitutes the above-mentioned mileage measuring means, regeneration area judging means and accumulation amount estimating means. More specifically, the traveling distance measuring means is executed by step S21 in FIG. 7, the reproduction area determining means is executed by step S22 in FIG. 7, and the deposition amount estimating means is executed by step S23 and step S24 in FIG. It is configured. The details of step S22 in FIG. 7 are the same as those in the flowchart of FIG. 4 described above.

Here, the control procedure will be described with reference to the flowchart of FIG.
Based on the travel distance signal 15a from 5, the travel distance is measured as a substitute value of the generation amount of particulates, and then,
When it is determined in step S22 that the current driving state is in the regeneration area, the process proceeds to step S23, measurement of the traveling distance is stopped, and in step S22, the current driving state is determined to be in the regeneration area. Only when it is not, the process proceeds to step S24 to continue measuring the traveling distance and integrate only the traveling distance in the non-reproduction area.

Further, step S23 or step S24
If the execution of forced regeneration is confirmed in step S25, the process proceeds to step S26 and the traveling distance is reset to zero, but if the execution of forced regeneration is not confirmed in step S25. In step S27, the same travel distance measurement is repeated from the beginning while maintaining the travel distance.

In this case, therefore, it is considered that there is almost no new particulate accumulation in the regeneration area where the amount of particulates treated exceeds the amount collected, and the accumulation is ensured. By accumulating only the mileage in the non-regeneration area where the amount is increasing and using it as a guideline for the accumulated amount in the particulate filter 6, the accumulated mileage corresponding to the actual increase in the accumulated amount can be realized. become.

In addition, in the integration of the traveled distance, since the subtraction of the traveled distance corresponding to the combustion of the particulates already accumulated in the regeneration region is not taken into consideration, there is almost no accumulation of new particulates. While the mileage is properly excluded, the accumulated mileage is estimated so that the accumulated amount of particulates accumulates, and at least the actual amount accumulated is estimated. Since it is possible to prevent the excessive subtraction of the traveling distance, it is determined that the particulate filter 6 which has already fallen into the over-collection state has a small accumulated amount of the particulate because the traveling distance is not yet sufficient. This can be avoided.

Therefore, also in this embodiment, it is possible to realize the estimation of the accumulated amount of particulates close to the actual state by using the traveling distance as a substitute value, and based on this, the forced regeneration of the particulate filter is performed at an appropriate interval. Since it is possible to determine the time of, it is possible to make the forced regeneration interval longer than before and reduce the energy cost associated with forced regeneration, and also to prevent the amount of particulates from falling below the actual deposition amount. Safety can be secured by estimating the amount of deposits.

The exhaust gas purifying apparatus of the present invention is not limited to the above-described embodiment, and means other than those described above may be adopted as the fuel adding means. Needless to say, various changes can be made without departing from the range.

[0051]

According to the exhaust gas purification apparatus of the present invention described above, various excellent effects as described below can be obtained.

(I) According to the first and second aspects of the present invention, it is possible to realize the estimation of the accumulated amount of particulates close to the actual state, and on the basis of this, the estimation of the particulate amount can be performed at appropriate intervals. Since the time for forced regeneration of the curate filter can be determined, the forced regeneration interval can be made longer than before to reduce the energy cost associated with forced regeneration, and the actual deposition amount is not reduced. Safety can be secured by estimating the amount of particulate accumulation as described above.

(II) According to the third aspect of the present invention, it is possible to determine that the particulate filter is in the regenerating state when the actually measured exhaust gas temperature exceeds the threshold value for a predetermined time or longer. It is possible to accurately grasp the fact that the processing amount of particulates exceeds the collection amount in the operating state.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an example of an embodiment for carrying out the present invention.

FIG. 2 is a cross-sectional view showing details of the particulate filter of FIG.

FIG. 3 is a flowchart showing a specific control procedure by the control device of FIG.

FIG. 4 is a flowchart showing details of step S5 in FIG.

FIG. 5 is a graph illustrating a reproduction area of a particulate filter.

FIG. 6 is a graph showing a transition of the accumulation amount across the reproduction area.

FIG. 7 is a flowchart showing a control procedure in another embodiment of the present invention.

[Explanation of symbols]

1 Diesel engine (internal combustion engine) 3 exhaust gas 4 exhaust pipe 6 Particulate filter 10 Temperature sensor 10a detection signal 11 Control device 15 rangefinder 15a Mileage signal S1 step (generation amount estimation means) S2 step (generation amount estimation means) S3 step (generation amount estimation means) S4 step (generation amount estimation means) S5 step (playback area determination means) S6 step (accumulation amount estimation means) S7 step (accumulation amount estimation means) Step S11 (playback area determination means) Step S12 (playback area determination means) Step S13 (playback area determination means) Step S14 (playback area determination means) S21 step (distance measuring means) S22 step (playback area determination means) Step S23 (deposition amount estimating means) S24 step (accumulation amount estimation means)

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F01N 3/18 F01N 3/18 B C F02D 45/00 314 F02D 45/00 314Z F term (reference) 3G084 AA01 BA13 BA24 DA27 EB02 FA10 FA33 3G090 AA03 BA01 CA01 DA00 DA12 DA18 3G091 AA18 AB02 AB13 BA13 BA33 CA02 CB02 DB06 DB10 EA01 EA07 EA17 FB01 FC01 GA06 HA14

Claims (3)

[Claims] 1. An exhaust gas purification device equipped with a catalyst regeneration type particulate filter in the middle of an exhaust pipe through which exhaust gas flows, the generation amount estimation for estimating the generation amount of particulates based on the operating state of an internal combustion engine. Means, a reproduction area determination means for determining whether or not the amount of particulates processed in the current operation state is in a reproduction area exceeding the trapping amount, and the current operation state in the reproduction area by the reproduction area determination means. The generation amount of particulates estimated by the generation amount estimating means while it is determined to be present is excluded, and only the generation amount of particulates in the non-reproduction region is integrated to obtain the accumulation amount in the particulate filter. An exhaust emission control device, comprising: an accumulation amount estimating means. 2. An exhaust gas purification device equipped with a catalyst regeneration type particulate filter in the middle of an exhaust pipe through which exhaust gas flows, and a mileage measuring means for measuring a mileage as a substitute value of the amount of generated particulates. And a regeneration region determining means for determining whether or not the amount of particulates processed in the current operating state is in a regeneration region exceeding the trapping amount, and the current operating state is in the regeneration region by the regeneration region determining means. While the determination is made, the traveling distance measured by the traveling distance measuring means is excluded, and only the traveling distance in the non-regeneration area is integrated, and the accumulated amount estimating means is used as a guide for the accumulated amount in the particulate filter. An exhaust emission control device comprising: 3. A regeneration region determining means for determining a regeneration region when the exhaust gas temperature at which the treated amount of particulates and the trapped amount are substantially equal is set as a threshold and the actually measured exhaust temperature exceeds the threshold for a predetermined time or more. The exhaust emission control device according to claim 1 or 2, wherein