JP4103748B2 - Exhaust gas purification device for internal combustion engine - Google Patents

Description

  The present invention relates to an exhaust gas purification apparatus for an internal combustion engine having a filter for collecting PM (Particulate Matter), which is particulate matter in exhaust gas, in an exhaust passage, and particularly relates to a regeneration technique for the filter.

Conventionally, as shown in Patent Document 1, a PM collection filter is disposed in the exhaust passage, and at a predetermined regeneration time, a regeneration process for increasing the temperature of the filter is performed to collect PM collected in the filter. Combustion removal is performed.
For the regeneration timing determination, since the pressure loss increases by clogging of the filter, by detecting the differential pressure across the filter (the pressure difference between the upstream side and downstream side), PM accumulation amount (PM trap amount ) Is estimated, and if this exceeds the reference value, it is determined that the regeneration period has been reached.

By the way, PM accumulates on the filter from its rear part (downstream side), but when regeneration is started, the temperature at the center of the filter is higher than that at the periphery of the filter. It starts from the center and gradually spreads to the periphery.
For this reason, if the operation state changes during regeneration and jumps into an operation state in which regeneration cannot be continued and the regeneration is interrupted, a partial regeneration state is entered, but the PM in the surrounding area remains unburned. Uneven distribution occurs. When PM is unevenly distributed and begins to deposit, the differential pressure across the filter appears with respect to the amount of PM deposited. Therefore, the relationship between the differential pressure before and after the filter and the PM accumulation amount changes between after complete regeneration and after partial regeneration (after regeneration interruption).

Therefore, after partial regeneration (after regeneration interruption), the amount of accumulated PM is estimated from the differential pressure before and after the filter, and when the estimated value reaches the reference value, when regeneration is started, the estimation error causes a comparison with Since the actual PM deposition amount is large, there is a problem that the temperature in the filter rapidly increases and may exceed the limit temperature.
The present invention has been made in view of the above-described conventional problems, and it is an object of the present invention to improve the estimation accuracy of the PM accumulation amount after partial regeneration (after regeneration interruption) and to optimize the judgment of the regeneration time. And

Therefore, in the present invention, when the regeneration timing is determined after partial regeneration (after regeneration interruption), a correction coefficient for the differential pressure across the filter is set according to the PM remaining amount at the time of regeneration interruption, By multiplying the detected value by a correction coefficient, the differential pressure before and after used for estimating the PM accumulation amount is corrected.
Furthermore, the correction coefficient is set according to the current vehicle speed in addition to the PM remaining amount at the time of regeneration interruption.

According to the present invention, when PM is unevenly distributed after partial regeneration (after regeneration is interrupted), the error due to PM uneven distribution is corrected by correcting the differential pressure across the filter according to the remaining amount of PM. Thus, the estimation accuracy of the PM deposition amount can be improved, and regeneration can be performed at an appropriate timing.
Also, by correcting the differential pressure across the filter according to the current vehicle speed, the higher the vehicle speed, the easier it is to regenerate. Can do.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a system diagram of a vehicle diesel engine showing an embodiment of the present invention.
The combustion chamber 2 of each cylinder of the diesel engine 1 passes through an intake air cleaner 3, an intake compressor 5, an intercooler 6, an intake throttle valve 7, and an intake manifold 8 of the variable nozzle supercharger 4. Is inhaled. The fuel supply system includes a fuel injection valve 9 that guides high-pressure fuel accumulated in a common rail (not shown) and injects fuel into the combustion chamber 2 of each cylinder at an arbitrary timing. During the compression stroke, fuel injection (main injection) is performed, and combustion is performed by compression ignition. The exhaust after combustion is discharged through an exhaust manifold 10 of the exhaust system and an exhaust turbine 11 of the variable nozzle supercharger 4.

Here, in order to purify PM in the exhaust discharged from the diesel engine 1, a diesel particulate filter (hereinafter referred to as "DPF") 12 is provided in the exhaust passage, thereby collecting the PM.
As shown in the perspective view of FIG. 2, the DPF 12 is a honeycomb structure made of porous ceramic and having a columnar outer shape, and is housed in a cylindrical casing (not shown) via a holding mat.

  The internal structure of the DPF 12 will be described. As shown in FIG. 3 which is an enlarged sectional view of the honeycomb structure, a plurality of parallel cell spaces 22 are provided by being partitioned by the porous lattice cell walls 21 of the honeycomb structure. Each cell space 22 extends in the exhaust flow direction. In the adjacent ones of the cell spaces 22, one is sealed on the outlet side and the other is sealed on the inlet side by sealing materials 23 and 24, respectively.

A cell space 22 having an inlet side opened and an outlet side sealed by a sealing material 23 is an exhaust inflow side cell space 22A, and a cell space 22 having an inlet side sealed by a sealing material 24 and having an outlet side opened. Is the exhaust gas outlet side cell space 22B.
Here, the exhaust from the engine flows into the exhaust inflow side cell space 22A and flows into the exhaust outflow side cell space 22B only through the porous cell wall 21 (its pores). PM in exhaust can be reliably collected.

  When the amount of accumulated PM increases due to the collection of PM by the DPF 12, the exhaust resistance increases and the drivability deteriorates. Therefore, it is determined whether or not it is a predetermined regeneration time. In the case of the regeneration time, regeneration processing means (means for raising the temperature of the DPF 12, more specifically, the exhaust gas temperature flowing into the DPF 12), for example, the fuel injection valve 9 Delay in fuel injection timing (main injection timing), post-injection as additional fuel injection in the expansion stroke or exhaust stroke by the fuel injection valve 9, reduction in opening of the intake throttle valve 7 (reduction in intake amount → rich air-fuel ratio) The PMF is burned using a decrease in the supercharging pressure by the variable nozzle type supercharger 4 (intake amount decrease → air-fuel ratio enrichment → exhaust temperature increase) or the like. Reproduce.

  Therefore, as shown in FIG. 1, the engine speed is detected by an engine control unit (hereinafter referred to as ECU) 13 that controls the operation of the fuel injection valve 9, the intake throttle valve 7, and the variable nozzle supercharger 4. In addition to a rotation speed sensor 14 that detects engine load (for example, accelerator opening), a vehicle speed sensor 16 that detects vehicle speed, and the like, a difference that detects a differential pressure across the DPF 12 to detect pressure loss at the DPF 12. The pressure sensors 17 and the exhaust temperature sensors 18 and 19 for detecting the exhaust temperatures on the inlet side and the outlet side of the DPF 12 are input.

Here, the ECU 13 detects the differential pressure across the DPF 12 based on the signal from the differential pressure sensor 17, and estimates the PM accumulation amount based on the detected differential pressure before and after. Then, the regeneration time is determined based on the estimated amount of accumulated PM, and when it is determined that the regeneration time is reached, the regeneration process is performed on the condition that a predetermined regeneration execution condition (recyclable operation state) is satisfied.
Next, specific control contents by the ECU 13 will be described with reference to the flowcharts of FIGS. 4 and 5.

FIG. 4 is a flowchart for determining the reproduction time, which is executed as a background job.
In S1, it is determined whether it is after complete reproduction (previous reproduction is complete reproduction) or partial reproduction (after reproduction interruption; previous reproduction is partial reproduction).
If it has been completely reproduced, the process proceeds to S2. The case after partial reproduction (after reproduction interruption) will be described later.

In S2, the signal of the differential pressure sensor 17 is read to detect the front-rear differential pressure ΔP of the DPF 12, and this is defined as α.
In S3, the exhaust flow rate Ve is estimated by referring to a map from the engine speed and the load (accelerator opening).
In S4, referring to a predetermined map, the PM accumulation amount of the DPF 12 is estimated from the DPF front-rear differential pressure ΔP = α and the exhaust flow rate Ve, and this is set as PMα.

Here, since the differential pressure across the DPF increases with the increase in the PM deposition amount, the PM deposition amount is estimated to increase as the differential pressure across the DPF increases. However, the differential pressure across the DPF also changes depending on the exhaust flow rate and is the same. Since the PM accumulation amount increases as the exhaust gas flow rate increases, the estimated value of the PM accumulation amount is corrected by the exhaust gas flow rate.
In S5, it is determined whether or not PM accumulation amount (PMα) ≧ PMγ by comparing the estimated PM accumulation amount (PMα) with the reference value (PMγ) for determining the regeneration timing.

If the PM accumulation amount <PMγ, it is determined that it is not the regeneration time, and the process returns to S2. However, if PM accumulation amount ≧ PMγ, the regeneration time (regeneration required) is determined, and the regeneration control is performed from S6 (FIG. 5). Go to).
FIG. 5 is a flowchart of the reproduction control, which is executed following S6 (or S19) in FIG.

In S21, when it is determined that the regeneration time is reached, it is determined whether or not the current operation condition satisfies the regeneration execution condition. The regeneration execution condition is set at any time other than idle operation, deceleration operation, and extremely low vehicle speed. If it is established, the process proceeds to S22 to start the reproduction process.
In S22, in order to regenerate the DPF 12, a regeneration process for increasing the temperature of the DPF 12 (the exhaust gas temperature flowing into the DPF 12) is performed, and the PM trapped in the DPF 12 is burned and removed. Specifically, for example, the delay of the fuel injection timing (main injection timing) of the fuel injection valve 9, post injection that is additional fuel injection in the expansion stroke or exhaust stroke by the fuel injection valve 9, and the intake throttle valve 7 The exhaust gas temperature is increased by using a decrease in the opening degree or a decrease in the supercharging pressure by the variable nozzle type supercharger 4 to increase the temperature in the DPF 12 to a temperature at which PM can be combusted. The collected PM is burned and removed. In this case, the target DPF inlet side exhaust temperature is set as the target regeneration processing temperature, and based on this, the actual temperature is detected by the DPF inlet side exhaust temperature sensor 18, and the fuel injection timing (main injection timing) and post injection are detected. The amount or post injection timing, intake throttle valve opening, or supercharging pressure is controlled.

In S23, in order to determine whether or not a predetermined reproduction interruption condition is satisfied, it is determined whether or not the reproduction execution condition is not satisfied. If the reproduction execution condition is satisfied, the process proceeds to S24.
In S24, in order to determine whether or not a predetermined complete playback condition is satisfied, for example, it is determined whether or not a predetermined playback time has elapsed.

If the predetermined reproduction time has not elapsed, it is determined that the reproduction is not complete yet, and the process returns to S22 to continue the reproduction.
If the predetermined reproduction time has elapsed, it is determined that the reproduction is complete, and the fact that the reproduction is complete is stored in S25, and then the process proceeds to S27 and the reproduction process is terminated. Here, all the parameters changed to the values for the regeneration process in S22 are returned to the original values (normal values according to the operating state).

If it is determined in S23 that the regeneration execution condition is not satisfied, that is, if the operation shifts to idle operation, deceleration operation, or extremely low vehicle speed operation during the regeneration, it is determined that the regeneration should be interrupted, and the partial regeneration is performed in S26. After storing the message (reproduction interruption), the process proceeds to S27 and the reproduction process is terminated.
By the way, when the regeneration of the DPF 12 is started, the temperature of the DPF 12 rises to a reproducible temperature. However, since the temperature of the DPF 12 is raised by the exhaust gas, it is not uniform due to the exhaust flow rate distribution, and the temperature of the peripheral part is slightly lower than the central part. Therefore, the combustion removal of PM during regeneration starts from the center and gradually spreads to the periphery.

If the DPF 12 is completely regenerated, almost all of the PM in the DPF 12 is burned and removed. Therefore, after complete regeneration, the PM is uniformly layered from the rear (downstream side) of the DPF 12, as shown in FIG. PM is deposited and PM is not unevenly distributed. However, what is accumulated is the exhaust inflow side cell space 22A of FIG.
On the other hand, when the regeneration is interrupted and partial regeneration is performed, a large amount of PM remains in the periphery of the DPF 12 (remaining regeneration amount), as shown in FIG. In an unevenly distributed state with few central parts and many peripheral parts, it accumulates in a curved shape, resulting in uneven distribution of PM.

Here, in the case of the PM accumulation distribution after partial regeneration (with uneven distribution) as shown in FIG. 6B, the PM is large on the outside and small on the center, so that the complete accumulation as shown in FIG. When compared with the PM deposition distribution after regeneration (no uneven distribution), the pressure loss in the DPF 12 at the same PM deposition amount is reduced.
For this reason, an error occurs when the PM accumulation amount is estimated from the differential pressure across the DPF in the case where there is uneven distribution, as in the case where there is no uneven distribution.

Accordingly, when regeneration is started when the estimated value of the PM deposition amount reaches the reference value in the presence of uneven distribution, the actual PM deposition amount is larger than that in the case of no uneven distribution. As can be seen from the relationship between (and the DPF inlet side exhaust gas temperature) and the regeneration DPF temperature, the DPF temperature may rise rapidly and exceed the limit temperature.
Therefore, in the present invention, when the regeneration timing is determined after partial regeneration (after regeneration interruption), the remaining amount of PM at the time of regeneration interruption is estimated, and a correction coefficient is set according to this to determine the differential pressure across the DPF. By multiplying the detected value by a correction coefficient, the differential pressure across the DPF used for estimating the PM accumulation amount is corrected, thereby preventing an estimation error.

FIG. 8 shows the relationship between the differential pressure across the DPF and the PM deposition amount when the exhaust gas flow rate is constant. The characteristic after the complete reproduction of the solid line in the figure changes after the partial reproduction (after the reproduction is interrupted) as shown by the dotted line in the figure.
Conventionally, when the differential pressure before and after the DPF becomes γ regardless of whether it is after complete regeneration or after partial regeneration, it is determined that the PM accumulation amount has reached PMγ for determining the regeneration time. After the partial regeneration, when the actual differential pressure before and after DPF ΔP = α, the PM deposition amount is estimated as PMα based on the characteristics after complete regeneration even though the actual PM deposition amount is larger than PMγ, and PMγ If it is less, it will be misjudged.

Therefore, in the present invention, after partial regeneration, for example, when the actual differential pressure across the DPF ΔP = α ′, this is multiplied by the correction coefficient K to obtain β = α ′ × K, and PM is determined based on this β. The estimation accuracy is improved by estimating the accumulation amount as PMβ.
Here, the correction coefficient K is set to be larger as the PM remaining amount is larger in accordance with the PM remaining amount at the time when the reproduction is interrupted. This is because the greater the remaining amount of PM at the time of regeneration interruption, the greater the degree of uneven distribution, and the greater the remaining amount of PM, the more necessary it is to regenerate as soon as possible.

Furthermore, it is desirable to set the correction coefficient K according to the PM remaining amount at the time of regeneration interruption and the current vehicle speed. Here, the vehicle speed is set larger as the vehicle speed is higher. This is because when the vehicle speed is high, regeneration is possible even if the remaining amount of PM is small, and it is desirable to eliminate the uneven distribution state at an early stage.
For the same reason, when setting the correction coefficient K, the weighting of the remaining PM amount and the vehicle speed is changed according to the vehicle speed, and the higher the vehicle speed, the higher the weighting of the vehicle speed, and the lower the weighting of the PM remaining amount. Is desirable.

Therefore, the correction coefficient K is calculated by the following equation.
K = Kp x Wpmx + Kv x Wvsp
Kp is a correction coefficient set in accordance with the remaining PM amount at the time of reproduction interruption, and increases as the remaining PM amount increases as shown in FIG. 9 (1 ≦ Kp ≦ Kmax; Kmax is 2 for example).
Kv is a correction coefficient set according to the current vehicle speed, and increases as the vehicle speed increases (1 ≦ Kv ≦ Kmax; Kmax is 2 for example) as shown in FIG.

Wpmx is a weighting constant for Kp, Wvsp is a weighting constant for Kv, and Wpmx + Wvsp = 1.
Further, as shown in FIG. 11, Wvsp increases as the vehicle speed increases (0 ≦ Wvsp ≦ 1). Since Wpmx is Wpmx = 1−Wvsp, as shown in FIG. 11, it becomes smaller as the vehicle speed is higher (0 ≦ Wpmx ≦ 1).

The reproduction time determination after the partial reproduction (after reproduction interruption) will be described with reference to the flowcharts of FIGS. 12 and 4 (S1, S7 to S19).
FIG. 12 is a flowchart of PM remaining amount estimation at the time of regeneration interruption, and is executed at predetermined time intervals (Δt).
In S101, it is determined whether or not playback is in progress (S22 in FIG. 5 is being executed). If playback is in progress, the process proceeds to S102.

In S102, the DPF inlet side exhaust temperature Tin and the outlet side exhaust temperature Tout are detected from the signals of the exhaust temperature sensors 27 and 28, and the DPF temperature Tbed is estimated from these. Specifically, Tbed = k × (Tin + Tout) / 2 is estimated (where k is a constant).
In S103, the exhaust flow rate Ve is estimated by referring to a map from the engine speed and the load (accelerator opening).

In S104, the regeneration speed (PM processing amount per unit time) S is estimated by referring to a map from the DPF temperature Tbed and the exhaust flow rate Ve. The regeneration speed increases as the DPF temperature increases and the exhaust flow rate decreases (gas cooling decreases).
In S105, the PM processing amount ΔPMd = S × Δt is calculated by multiplying the reproduction speed S by the execution time interval Δt of this routine.

In S106, the PM processing amount ΔPMd is integrated to obtain a cumulative PM processing amount ΣPMd (ΣPMd = ΣPMd + ΔPMd), and the process returns.
If it is determined in S101 that reproduction is not being performed, the process proceeds to S107.
In S107, it is determined whether or not the reproduction is interrupted (when the process proceeds from S23 to S26 in FIG. 5), and if the reproduction is interrupted, the process proceeds to S108.

  In S108, the remaining PM amount at the time when the reproduction is interrupted is calculated. That is, during regeneration, the accumulated PM processing amount ΣPMd is calculated from the regeneration speed obtained from the DPF temperature and the exhaust gas flow rate and the regeneration time, and is read and accumulated from the PM accumulation amount PMs at the start of regeneration. The PM remaining amount PMx is calculated by subtracting the PM processing amount ΣPMd (PMx = PMs−ΣPMd). Note that the PM accumulation amount PMs at the start of regeneration is PMα obtained in S4 (or PMβ obtained in S17) when the regeneration time is determined.

Thereafter, and if the determination at S107 is not when the reproduction is interrupted, the process proceeds to S109, the accumulated PM processing amount ΣPMd is initialized to 0, and the process returns.
FIG. 4 shows the determination of the reproduction time after partial reproduction (after reproduction interruption) from S1 to S7 to S19.
If it is determined in S1 that after partial reproduction (after interruption of reproduction; the previous reproduction is partial reproduction), the process proceeds to S7.

In S7, the PM remaining amount PMx at the time of reproduction interruption calculated by the flow of FIG. 12 is read.
In S8, referring to the table (T1) in FIG. 9, the correction coefficient Kp corresponding to the PM remaining amount PMx at the time of the reproduction interruption is obtained.
In S9, the current vehicle speed VSP is detected from the signal from the vehicle speed sensor 16.

In S10, the table (T2) in FIG. 10 is referred to, and a correction coefficient Kv corresponding to the current vehicle speed VSP is obtained.
In S11, the table (T3) in FIG. 11 is referred to, and a weighting constant Wvsp is obtained from the current vehicle speed VSP.
In S12, a weighting constant Wpmx for the remaining amount of PM is obtained as Wpmx = 1−Wvsp.

In S13, the final correction coefficient K is calculated by the following equation using the correction coefficients Kp and Kv and the weighting constants Wpmx and Wvsp.
K = Kp x Wpmx + Kv x Wvsp
In S14, the signal of the differential pressure sensor 17 is read to detect the front-rear differential pressure ΔP of the DPF 12, and this is defined as α.

In S15, the detected value (α) of the differential pressure before and after the DPF is multiplied by the correction coefficient K to obtain the differential pressure before and after the DPF (β) for estimating the PM accumulation amount as in the following equation.
β = α × K
In S16, the exhaust flow rate Ve is estimated by referring to a map from the engine speed and load (accelerator opening).

In S17, referring to a predetermined map, the PM accumulation amount of the DPF 12 is estimated from the DPF front-rear differential pressure ΔP = β and the exhaust flow rate Ve, and this is defined as PMβ.
In S18, it is determined whether or not PM accumulation amount (PMβ) ≧ PMγ by comparing the estimated PM accumulation amount (PMβ) with the reference value (PMγ) for determining the regeneration timing.
If PM deposition amount <PMγ, it is determined that it is not the regeneration time, and the process returns to S9. However, if PM deposition amount ≧ PMγ, it is determined that the regeneration time is required (regeneration is required), and regeneration control is performed from S19 (FIG. 5). Go to).

  As described above, according to the present embodiment, the correction coefficient for the differential pressure across the DPF for estimating the PM accumulation amount is set according to the PM remaining amount at the time of regeneration interruption, and in particular, as the PM remaining amount increases. By setting a large value, it is possible to improve the estimation accuracy of the PM deposition amount in consideration of the degree of PM uneven distribution, etc., and the more the remaining PM amount, the earlier the regeneration time and the early release of the uneven distribution state. be able to.

Further, according to the present embodiment, the correction coefficient for the differential pressure across the DPF for estimating the PM accumulation amount is set according to the remaining PM amount at the time of regeneration interruption and the current vehicle speed, and particularly, the higher the vehicle speed, the larger the correction coefficient. By setting, the higher the vehicle speed, the easier the regeneration, so that the regeneration time can be advanced earlier and the uneven distribution state can be eliminated earlier.
Further, according to the present embodiment, when setting the correction coefficient, the weighting of the PM remaining amount and the vehicle speed is changed according to the vehicle speed, and in particular, the higher the vehicle speed, the greater the weighting of the vehicle speed, thereby increasing the PM accumulation. Even if the amount is small, if regeneration is possible from the operating state, the control is changed to advance the regeneration time, and the uneven distribution state can be eliminated earlier.

  Further, according to the present embodiment, when estimating the PM remaining amount at the time of regeneration interruption, during regeneration, the cumulative PM processing amount is calculated from the regeneration speed obtained from the DPF temperature and the exhaust gas flow rate and the regeneration time, By calculating the PM remaining amount by subtracting the accumulated PM processing amount from the PM accumulation amount at the start of regeneration, the PM remaining amount can be accurately estimated.

The system diagram of the diesel engine which shows one Embodiment of this invention Schematic perspective view of DPF Enlarged sectional view showing the internal structure of the DPF Flow chart for playback time judgment Flow chart for playback control Diagram showing PM deposition distribution after complete regeneration and partial regeneration The figure which shows the relationship between PM accumulation amount and DPF temperature at the time of reproduction The figure which shows the relationship between DPF front-back differential pressure and PM accumulation amount The figure which shows the relationship between PM remaining amount and correction coefficient Diagram showing the relationship between vehicle speed and correction factor Diagram showing the relationship between vehicle speed and weighting constant Flow chart for estimating remaining PM when playback is interrupted

Explanation of symbols

1 Diesel engine
4 Variable nozzle supercharger
7 Inlet throttle valve
9 Fuel injection valve
12 DPF
13 ECU
14 Speed sensor
15 Load sensor
16 Vehicle speed sensor
17 Differential pressure sensor
18, 19 Exhaust temperature sensor

Claims (6)

The exhaust passage is provided with a filter for collecting PM in the exhaust, and a front-rear differential pressure detecting means for detecting a front-rear differential pressure of the filter, and a PM deposit amount for estimating the PM deposit amount based on the detected front-rear differential pressure An estimation unit, a regeneration timing determination unit that determines a regeneration timing based on the estimated amount of accumulated PM, and a regeneration process that increases the temperature of the filter when the regeneration timing is determined, and is collected by the filter. In an exhaust gas purification apparatus for an internal combustion engine comprising a regeneration processing means for burning and removing the PM that is burned,
In order to determine the playback time after interrupting playback during the previous playback,
PM remaining amount estimating means for estimating the PM remaining amount at the time of regeneration interruption based on the previous driving history during regeneration;
Correction coefficient setting means for setting a correction coefficient for the differential pressure across the filter according to the remaining PM amount at the time of regeneration interruption and the current vehicle speed ;
A front-rear differential pressure correcting means for correcting the front-rear differential pressure used in the PM deposition amount estimating means by multiplying the detected front-rear differential pressure by a correction coefficient;
An exhaust gas purification apparatus for an internal combustion engine, characterized by comprising:   2. The exhaust gas purification apparatus for an internal combustion engine according to claim 1, wherein the correction coefficient setting means increases the correction coefficient as the PM remaining amount increases. 3. The exhaust gas purification apparatus for an internal combustion engine according to claim 1 , wherein the correction coefficient setting means increases the correction coefficient as the vehicle speed increases. The internal combustion engine according to any one of claims 1 to 3, wherein the correction coefficient setting means changes the weighting of the PM remaining amount and the vehicle speed in accordance with the vehicle speed when setting the correction coefficient. Exhaust purification equipment. The exhaust gas purification apparatus for an internal combustion engine according to claim 4 , wherein the correction coefficient setting means increases the weighting of the vehicle speed as the vehicle speed increases. The PM remaining amount calculating means calculates the accumulated PM processing amount from the regeneration speed and the regeneration time obtained from the filter temperature and the exhaust gas flow rate during regeneration, and calculates the accumulated PM from the PM accumulation amount at the start of regeneration. The exhaust gas purification apparatus for an internal combustion engine according to any one of claims 1 to 5 , wherein the PM remaining amount is calculated by subtracting the processing amount.

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