JP2010112254A - Abnormality determination system for particulate filter - Google Patents

Abstract

The present invention provides a technique capable of determining an abnormality of a particulate filter provided in an exhaust passage of an internal combustion engine with higher accuracy.
An abnormality of the filter is determined based on a change in the temperature of the exhaust gas flowing out from the filter when the temperature of the exhaust gas is lowered without decreasing the flow rate of the exhaust gas flowing into the filter.
[Selection] Figure 1

Description

  The present invention relates to an abnormality determination system for a particulate filter provided in an exhaust passage of an internal combustion engine.

A particulate filter (hereinafter simply referred to as a filter) may be provided in the exhaust passage of the internal combustion engine in order to collect particulate matter (hereinafter referred to as PM) in the exhaust gas.

Patent Document 1 discloses a technique related to such a filter abnormality determination. In the technique described in Patent Document 1, the degree of decrease in the outflow exhaust temperature with respect to the inflow exhaust temperature during the deceleration operation is calculated, and when the degree of decrease exceeds a threshold, it is determined that the filter is abnormal.
JP 2006-2736 A JP 2008-45478 A JP 2008-75571 A JP 2007-154769 A

  An object of the present invention is to provide a technique capable of determining an abnormality of a filter provided in an exhaust passage of an internal combustion engine with higher accuracy.

  In the present invention, the exhaust gas flowing out from the filter (hereinafter referred to as outflow exhaust gas) when the temperature of the exhaust gas is lowered without decreasing the flow rate of the exhaust gas flowing into the filter (hereinafter referred to as inflow exhaust gas). The abnormality of the filter is determined based on the temperature change.

More specifically, the particulate filter abnormality determination system according to the present invention is:
A system for determining an abnormality of a particulate filter provided in an exhaust passage of an internal combustion engine,
Temperature changing means for changing the temperature of the exhaust gas without changing the flow rate of the exhaust gas flowing into the particulate filter;
Based on the change in the temperature of the exhaust gas flowing out from the particulate filter when the temperature of the exhaust gas is lowered without decreasing the flow rate of the exhaust gas flowing into the particulate filter by the temperature changing means, And a determination means for determining abnormality.

  When abnormality such as melting or breakage occurs in the filter, the flow resistance of the exhaust gas in the filter decreases, and the flow velocity of the exhaust gas flowing in the filter increases. As a result, the response delay of the temperature decrease of the outflow exhaust gas with respect to the temperature decrease of the inflow exhaust gas becomes smaller than in the normal state. Therefore, the abnormality of the filter can be determined based on the change in the temperature of the outflow exhaust gas when the temperature of the inflow exhaust gas is lowered.

Here, when the operating state of the internal combustion engine is a decelerating operation, the temperature of the inflowing exhaust gas decreases. Therefore, the abnormality of the filter can be determined based on the change in the temperature of the outflowing exhaust gas at this time. However, during the deceleration operation, the temperature of the inflowing exhaust gas decreases and the flow rate of the exhaust gas decreases. When the flow rate of the inflowing exhaust gas is small, the difference in the flow velocity of the exhaust gas flowing through the filter between when the filter is normal and when the filter is abnormal becomes small. For this reason, the difference in the change in the temperature of the exhaust gas between when the filter is normal and when the filter is abnormal is reduced. As a result, the accuracy of the filter abnormality determination may be reduced.

  Therefore, in the present invention, filter abnormality determination is performed based on a change in the temperature of the outflow exhaust gas when the temperature of the exhaust gas is decreased without decreasing the flow rate of the inflow exhaust gas. When the temperature of the exhaust gas is lowered without reducing the flow rate of the inflowing exhaust gas, the difference in the temperature change of the outflowing exhaust gas between when the filter is normal and when an abnormality occurs in the filter becomes large.

  Therefore, according to the present invention, it is possible to determine a filter abnormality with higher accuracy.

  In the present invention, the abnormality of the filter may be determined based on the difference between the temperature of the inflowing exhaust gas and the temperature of the outflowing exhaust gas when the temperature of the exhaust gas is decreased without decreasing the flow rate of the inflowing exhaust gas. For example, if the integrated value during a predetermined period of the difference between the temperature of the inflowing exhaust gas and the temperature of the outflowing exhaust gas at this time is smaller than a predetermined temperature difference integrated amount, it can be determined that the filter is abnormal.

  Further, the estimated value of the temperature of the outflow exhaust gas when the temperature of the exhaust gas is decreased without reducing the flow rate of the inflowing exhaust gas (that is, the value of the temperature of the outflow exhaust gas estimated when the filter is assumed to be normal). ) And the measured value may be used to determine the filter abnormality. For example, if the integrated value during the predetermined period of the difference between the estimated value of the exhaust gas at this time and the actually measured value is larger than the predetermined temperature difference integrated amount, it can be determined that the filter is abnormal.

  In the present invention, there is further provided setting means for setting a length of a period during which the temperature of the inflowing exhaust gas is lowered by the temperature changing means (hereinafter referred to as a temperature reduction period) in order to determine the abnormality of the filter by the determining means. Also good. In this case, the setting means shortens the length of the temperature reduction period as the exhaust gas temperature decrease amount increases when the exhaust gas temperature change means decreases the inflow exhaust gas temperature.

  The greater the amount of decrease in the temperature of the inflowing exhaust gas, the greater the difference in the change in the temperature of the outflowing exhaust between when the filter is normal and when an abnormality occurs in the filter. For this reason, the greater the amount of decrease in the temperature of the inflowing exhaust gas, the shorter the filter abnormality can be determined based on the change in the temperature of the outflowing exhaust gas.

  Therefore, according to the above, it is possible to determine the abnormality of the filter in as short a period as possible while ensuring high accuracy.

  In the above case, the temperature decrease period may be set as a period until the integrated value of the flow rate of the inflowing exhaust gas reaches a predetermined integrated flow rate. In this case, the setting means decreases the predetermined flow rate integrated amount as the exhaust gas temperature decrease amount increases when the exhaust gas temperature changing means decreases the inflow exhaust gas temperature. As a result, the greater the amount of decrease in the temperature of the inflowing exhaust gas, the shorter the period for performing the filter abnormality determination based on the change in the temperature of the outflowing exhaust gas.

  In the present invention, the temperature changing means has a sub-passage whose one end and the other end are connected to the exhaust passage upstream of the filter, and a switching means for switching whether or not exhaust gas is allowed to flow through the sub-passage. May be. In this case, the length of the sub passage may be longer than the length from the connection portion at one end of the sub passage to the connection portion at the other end of the sub passage in the exhaust passage. Moreover, you may provide the cooler which cools the exhaust_gas | exhaustion which distribute | circulates this subpassage in a subpassage. According to such a configuration, the temperature of the inflowing exhaust gas can be lowered by circulating the exhaust gas through the sub-passage.

  Further, when a catalyst having an oxidizing function is provided in the exhaust passage upstream of the filter, a sub-passage may be formed so as to bypass the catalyst. Even in such a configuration, the temperature of the inflowing exhaust gas can be lowered by circulating the exhaust gas through the sub-passage.

  The temperature changing means may include a cooler that is provided in the exhaust passage upstream of the filter and cools the exhaust gas flowing through the exhaust passage. In this case, the temperature of the inflowing exhaust gas can be lowered by the cooler.

  In the present invention, the determination means reduces the temperature of the inflowing exhaust gas in addition to the change in the temperature of the outflowing exhaust gas when the temperature of the inflowing exhaust gas is decreased without reducing the flow rate of the inflowing exhaust gas by the temperature changing means. The abnormality of the filter may be determined based on a change in the temperature of the outflow exhaust gas when the temperature of the exhaust gas is raised from the state by the temperature changing means.

  Even when the temperature of the inflowing exhaust gas is raised, a response delay occurs in the temperature rise of the outflowing exhaust gas. The response delay at this time is also smaller when an abnormality occurs in the filter than when the filter is normal.

  According to the above, it is possible to further improve the accuracy of the filter abnormality determination.

  According to the present invention, the abnormality of the filter provided in the exhaust passage of the internal combustion engine can be determined with higher accuracy.

  Hereinafter, specific embodiments of a filter abnormality determination system according to the present invention will be described with reference to the drawings. The dimensions, materials, shapes, relative arrangements, and the like of the components described in the present embodiment are not intended to limit the technical scope of the invention to those unless otherwise specified.

<First Example>
(Schematic configuration of internal combustion engine and its intake and exhaust system)
FIG. 1 is a diagram showing a schematic configuration of an internal combustion engine and an intake / exhaust system thereof according to the present embodiment. The internal combustion engine 1 is a diesel engine for driving a vehicle having four cylinders 2. Each cylinder 2 is provided with a fuel injection valve 3 that directly injects fuel into the cylinder 2.

  An intake manifold 5 and an exhaust manifold 7 are connected to the internal combustion engine 1. One end of an intake passage 4 is connected to the intake manifold 5. One end of an exhaust passage 6 is connected to the exhaust manifold 7.

  A compressor housing 8 a of a turbocharger 8 is installed in the intake passage 4. A turbine housing 8 b of a turbocharger 8 is installed in the exhaust passage 6.

  An air flow meter 11 is provided in the intake passage 4 upstream of the compressor housing 8a. A throttle valve 12 is provided in the intake passage 4 on the downstream side of the compressor housing 8a.

  An oxidation catalyst 9 is provided in the exhaust passage 6 on the downstream side of the turbine housing 8b. A filter 10 is provided downstream of the oxidation catalyst 9 in the exhaust passage 6.

  One end and the other end of the sub-passage 15 are connected between the oxidation catalyst 9 and the filter 10 in the exhaust passage 6. The sub-passage 15 is formed so that its length is longer than the length from the connection portion at one end of the sub-passage 15 to the connection portion at the other end of the sub-passage 15 in the exhaust passage 6. Further, a switching valve 16 for switching whether or not exhaust gas flows to the sub-passage 15 side is provided at a connection portion of the exhaust passage 6 with one end (upstream end) of the sub-passage 15.

  An upstream side that detects the temperature of the exhaust gas flowing into the filter 10 (inflowing exhaust gas) downstream of the connecting portion of the exhaust passage 6 with the other end (downstream end portion) of the auxiliary passage 15 and upstream of the filter 10. A temperature sensor 13 is provided. Further, a downstream temperature sensor 14 for detecting the temperature of the exhaust gas flowing out from the filter 10 (outflow exhaust gas) is provided downstream of the filter 10 in the exhaust passage 6.

  The internal combustion engine 1 is provided with an electronic control unit (ECU) 20. The ECU 20 is a unit that controls the operating state of the internal combustion engine 1 and the like. An air flow meter 11, an upstream temperature sensor 13, and a downstream temperature sensor 14 are electrically connected to the ECU 20. Output signals from the sensors are input to the ECU 20.

  In addition, each fuel injection valve 3, throttle valve 12, and switching valve 16 are electrically connected to the ECU 20. These are controlled by the ECU 20.

(Filter abnormality judgment method)
Next, a method for determining an abnormality such as melting or breakage of the filter according to the present embodiment will be described with reference to FIG. FIG. 2 is a time chart showing transitions of the inflowing exhaust gas temperature Tgin and the outflowing exhaust gas temperature Tgout when the exhaust gas flow path is switched to the sub passage 15 side by the switching valve 16. Note that “open” and “closed” in the switching valve in FIG. 2 represent the state of the exhaust passage. That is, when “open”, the exhaust passage side is opened and the sub-passage 15 side is blocked. On the other hand, when “closed”, the exhaust passage side is blocked and the sub-passage 15 side is opened.

  When the exhaust gas flows through the sub-passage 15, the length of the flow path of the inflowing exhaust gas becomes longer than when the exhaust gas flows only through the exhaust passage 6. Therefore, the amount of heat radiated before exhaust flows into the filter 10 increases. As a result, as shown in FIG. 2, the temperature Tgin of the inflowing exhaust gas decreases. In this case, the flow rate of the inflowing exhaust gas does not change.

  When the temperature Tgin of the inflowing exhaust gas is lowered, the temperature Tgout of the outflowing exhaust gas is also lowered accordingly. However, the filter 10 has a certain heat capacity. Therefore, a response delay occurs in the temperature decrease of the outflow exhaust gas with respect to the temperature decrease of the inflow exhaust gas. As a result, the temperature Tgout of the outflow exhaust gas becomes higher than the temperature Tgin of the inflow exhaust gas until the heat exchange between the exhaust gas and the filter 10 is completed.

  Here, when abnormality such as melting or breakage occurs in the filter 10, the flow rate of the exhaust gas flowing through the filter 10 is increased, so that the heat transfer amount from the filter 10 to the exhaust gas is reduced as compared with the normal time. As a result, compared with the case where the filter 10 is normal, the response delay of the temperature decrease of the outflow exhaust gas with respect to the temperature decrease of the inflow exhaust gas is reduced.

  Thus, as shown in FIG. 2, the difference between the temperature Tgin of the inflowing exhaust gas and the temperature Tgout of the outflowing exhaust gas when the exhaust flow path is switched to the sub-passage 15 side (hereinafter referred to as an input / output exhaust gas temperature difference) ΔTgio Is smaller than normal.

Therefore, in this embodiment, the intake / exhaust exhaust gas temperature difference ΔTgio during the period when the exhaust passage is switched to the sub-passage 15 side, that is, during the period (temperature decrease period) Δtd during which the temperature Tgin of the inflowing exhaust gas is decreased. Is accumulated. If the integrated value ΣΔTgio is smaller than a predetermined temperature difference integrated amount ΣΔTgio0, it is determined that the filter 10 is abnormal.

  Here, the predetermined temperature difference integrated amount ΣΔTgio0 is a threshold value of the integrated value of the input / output exhaust gas temperature difference at which it can be determined that the filter 10 is normal. Such a predetermined temperature difference integrated amount ΣΔTgio0 can be obtained in advance based on experiments or the like.

  Further, in this embodiment, when the temperature Tgin of the inflowing exhaust gas is decreased so as to determine the abnormality of the filter 10, the temperature is decreased without decreasing the flow rate of the inflowing exhaust gas. In this case, the response delay of the temperature decrease of the outflow exhaust gas becomes smaller than when the flow rate of the inflow exhaust gas is decreased when the temperature Tgin of the inflow exhaust gas is decreased. Therefore, the difference in the inlet / outlet exhaust gas temperature difference ΔTgio between when the filter 10 is normal and when the filter 10 is abnormal can be further increased.

  Therefore, according to the present embodiment, the abnormality of the filter 10 can be determined with higher accuracy.

  In this embodiment, the temperature decrease period Δtd is set based on the integrated value ΣQgin of the flow rate of the inflowing exhaust gas after the exhaust gas flow path is switched to the sub-passage 15 side. That is, the temperature decrease period Δtd is set as a period until the integrated value ΣQgin of the inflowing exhaust gas flow rate reaches the predetermined inflowing exhaust gas flow rate integrated amount ΣQgin0.

  Here, as the temperature drop amount ΔTgind of the inflowing exhaust gas when the exhaust flow path is switched to the sub-passage 15 side is larger, the input / output between when the filter 10 is normal and when the abnormality occurs in the filter 10 The difference in the exhaust gas temperature difference ΔTgio increases. Therefore, as the temperature drop amount ΔTgind of the inflowing exhaust gas is larger, the abnormality determination of the filter 10 based on the integrated value ΣΔTgio of the input / output exhaust gas temperature difference can be performed in a shorter period.

  Therefore, the predetermined inflow exhaust gas flow rate integrated amount ΣQgin0 is set to a smaller value as the temperature decrease amount ΔTgind is larger. Thereby, the period during which the abnormality determination of the filter 10 is performed can be made shorter as the temperature drop amount ΔTgind of the inflowing exhaust gas is larger.

  Thus, according to the present embodiment, it is possible to determine the abnormality of the filter 10 in as short a period as possible while ensuring high accuracy.

(Filter abnormality judgment flow)
Hereinafter, the flow of the filter abnormality determination according to the present embodiment will be described based on the flowchart shown in FIG. In the present embodiment, this flow is stored in the ECU 20, and the processing in each step is executed by the ECU 20 according to the procedure shown in the flowchart.

  In this flow, first, in step S101, it is determined whether or not an execution condition for determining abnormality of the filter 10 is satisfied. Here, as execution conditions, the temperature of the filter 10 is a predetermined value or more, the temperature of the filter 10 is stable (temperature fluctuation is within a predetermined range), and the temperature of the inflowing exhaust gas is a predetermined value or more. Etc. can be illustrated. The execution conditions are predetermined based on experiments and the like.

  If it is determined in step S101 that the determination condition is satisfied, then the process of step S102 is executed. In step S102, the switching valve 16 is closed. That is, the exhaust passage is switched to the sub passage 15 side. As a result, the temperature Tgin of the inflowing exhaust gas decreases.

  Next, in step S103, the temperature drop amount ΔTgind of the inflowing exhaust gas is calculated.

  Next, in step S104, a predetermined inflow exhaust gas flow rate integration amount ΣQgin0 is set based on the temperature drop amount ΔTgind of the inflow exhaust gas. The relationship between the temperature drop amount ΔTgind of the inflowing exhaust gas and the predetermined inflowing exhaust gas flow rate integrated amount ΣQgin0 is stored in advance in the ECU 20 as a map. In this map, the corresponding predetermined inflow exhaust gas flow amount integration amount ΣQgin0 becomes smaller as the temperature decrease amount ΔTgind of the inflow exhaust gas is larger.

  Next, in step S105, the temperature Tgin of the inflowing exhaust gas and the temperature Tgout of the outflowing exhaust gas are detected. At this time, the temperature Tgin of the inflowing exhaust gas is detected by the upstream temperature sensor 13, and the temperature Tgout of the outflowing exhaust gas is detected by the downstream temperature sensor 14.

  Next, in step S106, the inlet / outlet exhaust gas temperature difference ΔTgio is calculated based on the outflow exhaust gas temperature Tgout and the inflow exhaust gas temperature Tgin.

  Next, in step S107, an integrated value ΣΔTgio of the difference between the inlet and outlet exhaust temperatures is calculated.

  Next, in step S108, the integrated value ΣQgin of the flow rate of the inflowing exhaust gas after switching the exhaust flow path to the sub-passage 15 side in step S102 is equal to or greater than the predetermined inflowing exhaust gas flow rate integrated amount ΣQgin0 calculated in step S104. It is determined whether or not.

  If an affirmative determination is made in step S108, the process of step S109 is executed. On the other hand, if a negative determination is made in step S108, the processing from step S105 to S107 is executed again.

  In step S109, the switching valve 16 is opened. That is, the sub passage 15 side is blocked, and the exhaust passage is switched to the exhaust passage side. As a result, the temperature Tgin of the inflowing exhaust gas, which has been reduced, rises and returns to the temperature before the exhaust flow path is switched to the sub-passage 15 side.

  Next, in step S110, it is determined whether or not the integrated value ΣΔTgio of the intake / exhaust exhaust gas temperature difference during the temperature decrease period Δtd is smaller than a predetermined temperature difference integrated amount ΣΔTgio0. The predetermined accumulated temperature difference amount ΣΔTgio0 is stored in the ECU 20 in advance.

  If an affirmative determination is made in step S110, the process of step S111 is executed. In step S111, it is determined that the filter 10 is abnormal. On the other hand, if a negative determination is made in step S110, the process of step S112 is executed. In step S112, it is determined that the filter 10 is normal.

(Correspondence between components according to the present invention and this embodiment)
In the present embodiment, the auxiliary passage 15 and the switching valve 16 correspond to “temperature changing means” according to the present invention. The sub-passage 15 corresponds to the “sub-passage” according to the present invention, and the switching valve 16 corresponds to the “switching means” according to the present invention. The oxidation catalyst 9 corresponds to the “catalyst having an oxidation function” according to the present invention.

In this embodiment, the ECU 20 that executes steps S110 and S111 in the above flow corresponds to the “determination means” according to the present invention. In this embodiment, the ECU 20 that executes step S104 in the above flow corresponds to the “setting unit” according to the present invention.

(First modification)
FIG. 4 is a diagram illustrating a configuration in the vicinity of the sub-passage 18 of the exhaust passage 6 according to a first modification of the present embodiment. In the configuration according to the first modification, a cooler 19 is provided in the sub passage 18. When the exhaust gas flows through the sub passage 18, the exhaust gas is cooled by the cooler 19. According to such a configuration, the temperature Tgin of the inflowing exhaust gas can be further lowered when the exhaust gas flow path is switched to the sub passage 18 side in order to determine whether the filter 10 is abnormal.

  As a result, the intake / exhaust temperature difference ΔTgio can be further increased. Therefore, the abnormality determination of the filter 10 can be performed in a shorter period and with higher accuracy.

  In this case, the cooler 19 corresponds to a “cooler” according to the present invention.

(Second modification)
FIG. 5 is a diagram showing a schematic configuration in the vicinity of the sub-passage 18 of the exhaust passage 6 according to a second modification of the present embodiment. In the configuration according to the second modification, the auxiliary passage 18 is provided so as to bypass the oxidation catalyst 9. When the exhaust gas passes through the oxidation catalyst 9, it is heated by oxidation heat and the temperature rises. According to the configuration according to the modification, when the sub passage 18 is opened, the exhaust before being heated in the oxidation catalyst 9 flows through the sub passage 18.

  Therefore, as in the case of the first modification, the temperature Tgin of the inflowing exhaust gas can be further lowered when the exhaust gas flow path is switched to the sub-passage 18 side in order to determine whether the filter 10 is abnormal.

(Third modification)
FIG. 6 is a diagram showing a schematic configuration in the vicinity of the sub-passage 18 of the exhaust passage 6 according to a third modification of the present embodiment. In the configuration according to the third modification, the sub passage 18 is provided so as to bypass the oxidation catalyst 9, and the cooler 19 is provided in the sub passage 18.

  According to such a configuration, when the exhaust passage is switched to the sub-passage 18 side in order to determine the abnormality of the filter 10, the temperature Tgin of the inflowing exhaust gas is further lowered than in the first and second modified examples. Can be made.

(Fourth modification)
FIG. 7 is a diagram illustrating a schematic configuration of the exhaust passage 6 according to a fourth modification of the present embodiment. In the configuration according to the fourth modification, no sub-passage is provided, and a cooler 21 is provided between the oxidation catalyst 9 and the filter 10. The cooler 21 is electrically connected to the ECU 20 and can be turned ON / OFF by the ECU 20.

  Even in such a configuration, the temperature of the inflowing exhaust gas can be lowered without reducing the flow rate by turning on the cooler 21.

  In this case, the cooler 21 corresponds to “temperature changing means” and “cooler” according to the present invention.

(Other variations)
In the filter abnormality determination method, the abnormality of the filter 10 is determined based on the integrated value of the intake / exhaust exhaust gas temperature difference during the temperature decrease period. However, the determination can also be made based on the difference between the inlet and outlet exhaust gas temperatures at a predetermined timing during the temperature drop period. In this case, it is determined that the filter 10 is abnormal when the difference between the inlet and outlet exhaust gas temperatures at a predetermined timing is smaller than a predetermined threshold.

  Further, the abnormality of the filter 10 may be determined based on the integrated value of the inlet / outlet exhaust gas temperature difference during part of the temperature decrease period.

  In the above-described filter abnormality determination method, the temperature decrease period is set as a period until the integrated value of the flow rate of the inflowing exhaust gas reaches a predetermined integrated amount. However, the temperature decrease period can be set as a predetermined time. Also in this case, it is preferable to shorten the temperature decrease period as the temperature decrease amount of the inflowing exhaust gas when the temperature of the inflowing exhaust gas is decreased.

  Further, the temperature decrease period may be a period until the temperature of the outflow exhaust gas substantially coincides with the temperature of the inflow exhaust gas (that is, the period until the heat exchange between the filter 10 and the exhaust is completed).

<Second Example>
The schematic configuration of the internal combustion engine and its intake / exhaust system according to this embodiment is the same as that of the first embodiment.

(Filter abnormality judgment method)
As described above, when an abnormality occurs in the filter 10, the change in the temperature Tgout of the outflow exhaust gas when the temperature Tgin of the inflow exhaust gas is lowered is different from the normal time. That is, as shown in FIG. 2, the difference between the temperature of the outflow exhaust when the filter 10 is abnormal and the temperature Tgout of the outflow exhaust when the filter 10 is normal (hereinafter referred to as the outflow exhaust temperature difference). ) ΔTgout occurs.

  Therefore, in this embodiment, the temperature of the exhaust gas when the filter 10 is assumed to be normal is estimated. Then, the outflow exhaust gas temperature difference ΔTgout is calculated based on the estimated value Tgoutn and the actual measurement value Tgout detected by the downstream temperature sensor 14, and the outflow exhaust gas temperature difference ΔTgout during the temperature decrease period Δtd is integrated. To do. When the integrated value ΣΔTgiout is larger than a predetermined temperature difference integrated amount ΣΔTgout0, it is determined that the filter 10 is abnormal.

  Here, the predetermined temperature difference integrated amount ΣΔTgout0 is a threshold value of the integrated value of the outflow exhaust gas temperature difference at which it can be determined that the filter 10 is normal. Such a predetermined temperature difference integrated amount ΣΔTgout0 can be obtained in advance based on experiments or the like.

  Also in this embodiment, when the temperature Tgin of the inflowing exhaust gas is lowered to determine whether the filter 10 is abnormal, the flow rate of the inflowing exhaust gas is reduced by using the same method as in the first embodiment. Without lowering its temperature. Thereby, the difference of the outflow exhaust gas temperature difference ΔTgout between when the filter 10 is normal and when the filter 10 is abnormal can be further increased.

  Therefore, according to the present embodiment, the abnormality of the filter 10 can be determined with higher accuracy.

  Also in this embodiment, the temperature drop period Δtd is set in the same manner as in the first embodiment. Thereby, the abnormality determination of the filter 10 can be performed in as short a period as possible while ensuring high accuracy.

(Filter abnormality judgment flow)
Hereinafter, the flow of the filter abnormality determination according to the present embodiment will be described based on the flowchart shown in FIG. In the present embodiment, this flow is stored in the ECU 20, and the processing in each step is executed by the ECU 20 according to the procedure shown in the flowchart. In this flow, steps S105 to S107 and S110 in the flow shown in FIG. 3 are replaced with steps S205 to S208 and S210. Therefore, only the process of the replaced step will be described below, and the description of the process of the other steps will be omitted.

  In this flow, in step S205, the ECU 20 estimates the temperature Tgoutn of the exhaust gas when it is assumed that the filter 10 is normal. Here, the temperature Tgoutn of the outflow exhaust gas is determined from the time when the temperature of the inflowing exhaust gas and the temperature of the filter 10, the flow rate of the inflowing exhaust gas, and the flow path of the exhaust gas are switched. It is estimated based on the elapsed time of.

  Next, in step S206, the temperature Tgout of the outflow exhaust gas is detected. At this time, the temperature Tgout of the outflow exhaust gas is detected by the downstream temperature sensor 14.

  Next, in step S207, the outflow exhaust gas temperature difference ΔTgout is calculated based on the estimated value Tgoutn of the outflow exhaust gas temperature and the actual measurement value Tgout.

  Next, in step S208, an integrated value ΣΔTgout of the outflow exhaust gas temperature difference is calculated.

  In this flow, if a negative determination is made in step S108, the processing from step S205 to S208 is executed again.

  In step S210, it is determined whether or not the integrated value ΣΔTgout of the outflow exhaust gas temperature difference during the temperature decrease period Δtd is greater than a predetermined temperature difference integrated amount ΣΔTgout0. The predetermined temperature difference integrated amount ΣΔTgout0 is stored in the ECU 20 in advance.

  When an affirmative determination is made in step S210, the process of step S111 is executed. On the other hand, if a negative determination is made in step S210, the process of step S112 is executed.

(Correspondence between components according to the present invention and this embodiment)
In this embodiment, the ECU 20 that executes steps S210 and S111 in the above flow corresponds to the “determination means” according to the present invention.

(Modification)
Also in the present embodiment, the configuration according to each modification of the first embodiment can be employed. Also in this embodiment, the timing relating to the filter abnormality determination or the temperature drop period can be modified as in the other embodiment (other modification).

<Third embodiment>
The schematic configuration of the internal combustion engine and its intake / exhaust system according to this embodiment is the same as that of the first embodiment.

(Filter abnormality judgment method)
Also in this embodiment, when the abnormality of the filter 10 is determined, the temperature Tgin of the inflowing exhaust gas is lowered. Here, even when the temperature Tgin of the lowered inflow exhaust gas is raised, a response delay occurs in the change in the temperature of the outflow exhaust gas Tgout. The response delay at this time also becomes smaller when an abnormality occurs in the filter 10 than when the filter 10 is normal. For this reason, the difference between the inlet and outlet exhaust gas temperatures at this time is also different from the normal time.

Therefore, in this embodiment, not only the integrated value of the inlet / outlet exhaust gas temperature difference ΔTgiod when the exhaust passage is switched to the sub passage 15 side, but also the exhaust passage is returned from the sub passage 15 side to the exhaust passage side. The abnormality of the filter 10 is determined using the integrated value of the intake / exhaust exhaust gas temperature difference ΔTgiou as a parameter.

  Specifically, when the abnormality of the filter 10 is determined, first, the flow path of the exhaust is switched to the sub passage 15 side by the switching valve 16. In this embodiment, the temperature drop period Δtd is set to a period until the temperature Tgout of the outflow exhaust gas becomes substantially the same as the temperature Tgin of the inflow exhaust gas, and the intake / exhaust exhaust gas temperature difference ΔTgiod during this period is integrated.

  After the temperature Tgout of the outflow exhaust gas becomes substantially the same as the temperature Tgin of the inflow exhaust gas, the sub-passage 15 side is shut off by the switching valve 16 and the exhaust passage is switched to the exhaust passage side. As a result, the temperature Tgin of the inflowing exhaust gas increases. Then, the intake / exhaust exhaust gas temperature difference ΔTgiou from this point in time until the predetermined determination period Δtj elapses is integrated.

  The integrated value ΣΔTgiod of the difference between the input and output exhaust temperatures when the temperature Tgin of the inflowing exhaust gas is decreased and the integrated value ΣΔTgiou of the temperature difference of the input and output exhausts when the temperature Tgin of the inflowing exhaust gas is increased. Are both smaller than the respective threshold values, it is determined that the filter 10 is abnormal.

  According to this embodiment, it is possible to determine the abnormality with higher accuracy than in the case where the abnormality of the filter 10 is determined only by the integrated value ΣΔTgiod of the difference between the input and output exhaust gas temperatures when the temperature Tgin of the inflowing exhaust gas is lowered. You can

(Filter abnormality judgment flow)
Hereinafter, the flow of the filter abnormality determination according to the present embodiment will be described based on the flowchart shown in FIG. In the present embodiment, this flow is stored in the ECU 20, and the processing in each step is executed by the ECU 20 according to the procedure shown in the flowchart.

  In this flow, first, in step S301, it is determined whether or not an execution condition for determining abnormality of the filter 10 is satisfied. The execution conditions are the same as the execution conditions for the abnormality determination of the filter 10 according to the first embodiment.

  If it is determined in step S301 that the determination condition is satisfied, then the process of step S302 is executed. In step S302, the switching valve 16 is closed. That is, the exhaust passage is switched to the sub passage 15 side. As a result, the temperature Tgin of the inflowing exhaust gas decreases.

  Next, in step S303, the temperature Tgin of the inflowing exhaust gas and the temperature Tgout of the outflowing exhaust gas are detected. At this time, the temperature Tgin of the inflowing exhaust gas is detected by the upstream temperature sensor 13, and the temperature Tgout of the outflowing exhaust gas is detected by the downstream temperature sensor 14.

  Next, in step S304, the inlet / outlet exhaust gas temperature difference ΔTgiod is calculated based on the outflow exhaust gas temperature Tgout and the inflow exhaust gas temperature Tgin.

  Next, in step S305, an integrated value ΣΔTgiod of the difference between the inlet and outlet exhaust gas temperature is calculated.

  Next, in step S306, it is determined whether or not the temperature Tgout of the outflow exhaust gas and the temperature Tgin of the inflow exhaust gas are substantially the same.

  If an affirmative determination is made in step S306, the process of step S307 is executed. On the other hand, if a negative determination is made in step S306, the processing from steps S303 to S305 is executed again.

  In step S307, the switching valve 16 is opened. That is, the exhaust passage is switched to the exhaust passage side. As a result, the temperature Tgin of the inflowing exhaust gas increases.

  Next, in step S308, the temperature Tgin of the inflowing exhaust gas and the temperature Tgout of the outflowing exhaust gas are detected.

  Next, in step S309, the inlet / outlet exhaust gas temperature difference ΔTgiou is calculated based on the outflow exhaust gas temperature Tgout and the inflow exhaust gas temperature Tgin.

  Next, in step S310, an integrated value ΣΔTgiou of the intake / exhaust exhaust gas temperature difference is calculated.

  Next, in step S311, it is determined whether or not an elapsed time Δt after switching the exhaust flow path to the exhaust passage side has reached a predetermined determination time Δtj.

  If an affirmative determination is made in step S311, the process of step S312 is executed. On the other hand, if a negative determination is made in step S311, the processes from step S308 to S310 are executed again.

  In step S312, it is determined whether or not the integrated value ΣΔTgiod of the intake / exhaust exhaust gas temperature difference during the temperature decrease period Δtd is smaller than a predetermined temperature difference integrated amount ΣΔTgio1. The predetermined accumulated temperature difference amount ΣΔTgio1 is stored in the ECU 20 in advance.

  If an affirmative determination is made in step S312, the process of step S313 is executed. On the other hand, if a negative determination is made in step S312, the process of step S315 is executed. In step S315, it is determined that the filter 10 is normal.

  In step S313, the integrated value ΣΔTgio of the input / output exhaust gas temperature difference from when the exhaust passage is switched to the exhaust passage side in step S307 until the determination time Δtj elapses is a predetermined temperature difference integrated amount Σ. It is determined whether or not it is smaller than ΔTgio2. The predetermined temperature difference integrated amount ΣΔTgio2 is stored in the ECU 20 in advance.

  If an affirmative determination is made in step S313, the process of step S314 is executed. In step S314, it is determined that the filter 10 is abnormal. On the other hand, when a negative determination is made in step S313, the process of step S315 is executed.

(Correspondence between components according to the present invention and this embodiment)
In this embodiment, the ECU 20 that executes steps S312, S313, and S314 in the above flow corresponds to the “determination means” according to the present invention.

(Modification)
In the filter abnormality determination method described above, the filter 10 is determined to be abnormal when both the integrated values ΣΔTgiod and ΣΔTgio of the intake / exhaust exhaust gas temperature difference are smaller than the respective threshold values. However, each threshold value may be set so that the filter 10 can be determined to be abnormal when at least one of the integrated values ΣΔTgiod and ΣΔTgiou of the inlet / outlet exhaust gas temperature difference is smaller than the threshold value.

  Further, it may be determined whether or not the filter 10 is abnormal based on the sum of the integrated values ΣΔTgiod and ΣΔTgiou of the difference between the inlet and outlet exhaust temperatures.

  In the filter abnormality determination method, the temperature decrease period ΔTd is set as a period until the temperature Tgout of the outflow exhaust gas and the temperature Tgin of the inflow exhaust gas become substantially the same. However, also in the present embodiment, the temperature decrease period ΔTd may be made variable as in the first embodiment.

  In this case, there is a possibility that the exhaust flow path is switched to the exhaust passage side while the temperature Tgout of the outflow exhaust gas is decreasing. For this reason, the temperature Tgout of the outflow exhaust gas at the time of switching the exhaust gas flow path to the exhaust passage side may vary depending on the timing. Therefore, the threshold value for determining whether the filter 10 is abnormal (ΣΔTgio2 in the case of the above flow) is changed according to the temperature Tgout of the outflow exhaust gas at the time of switching the exhaust flow path to the exhaust passage side. Also good.

  Also in this embodiment, as in the modification of the first embodiment, based on the input / output exhaust gas temperature difference at a predetermined timing during the temperature drop period and the input / output exhaust gas temperature difference at a predetermined timing during the determination period. An abnormality determination of the filter 10 can also be performed.

  Also in the present embodiment, the configuration according to each modification of the first embodiment can be employed.

<Fourth embodiment>
The schematic configuration of the internal combustion engine and its intake / exhaust system according to this embodiment is the same as that of the first embodiment.

(Filter abnormality judgment method)
As described above, when an abnormality occurs in the filter 10, the change in the temperature Tgout of the outflow exhaust gas when the temperature Tgin of the inflowing exhaust gas once lowered is raised is different from that in the normal state. That is, even when the temperature Tgin of the inflowing exhaust gas is increased, the temperature difference of the outflowing exhaust gas is generated as in the case of decreasing the temperature.

Therefore, in this embodiment, not only the integrated value of the outflow exhaust gas temperature difference ΔTgoutd when the exhaust passage is switched to the sub-passage 15 side, but also the exhaust passage is returned from the sub-passage 15 side to the exhaust passage side. The abnormality of the filter 10 is determined using the integrated value of the outflow exhaust gas temperature difference ΔTgoutu as a parameter.

  Specifically, also in this embodiment, when the abnormality of the filter 10 is determined, the exhaust flow path is switched at the same timing as in the third embodiment. Then, the outflow exhaust gas temperature difference ΔTgoutd during the temperature decrease period Δtd is integrated. Further, the exhaust gas temperature difference ΔTgoutu during the determination period Δtj is integrated.

  The integrated value ΣΔTgoutd of the outflow exhaust gas temperature difference when the inflowing exhaust gas temperature Tgin is reduced and the integrated value ΣΔTgoutu of the outflowing exhaust gas temperature difference when the inflowing exhaust gas temperature Tgin is increased. Are both smaller than the respective threshold values, it is determined that the filter 10 is abnormal.

  According to the present embodiment, the abnormality can be determined with higher accuracy than when the abnormality of the filter 10 is determined only by the integrated value ΣΔTgoutd of the input / output exhaust gas temperature difference when the temperature Tgin of the inflowing exhaust gas is lowered. You can

(Filter abnormality judgment flow)
Hereinafter, the flow of the filter abnormality determination according to the present embodiment will be described based on the flowchart shown in FIG. In the present embodiment, this flow is stored in the ECU 20, and the processing in each step is executed by the ECU 20 according to the procedure shown in the flowchart. In this flow, steps S303 to S305, S308 to S310, S312 and S313 in the flow shown in FIG. 9 are replaced with S403 to S406, S408 to S411, S412 and S413. Therefore, only the process of the replaced step will be described below, and the description of the process of the other steps will be omitted.

  In this flow, in step S403, the temperature Tgoutn of the exhaust gas when it is assumed that the filter 10 is normal is estimated. Here, the temperature Tgoutn of the outflow exhaust gas is estimated by the same method as in step S205 of the flow shown in FIG.

  Next, in step S404, the temperature Tgout of the outflow exhaust gas is detected. At this time, the temperature Tgout of the outflow exhaust gas is detected by the downstream temperature sensor 14.

  Next, in step S405, the outflow exhaust gas temperature difference ΔTgoutd is calculated based on the estimated value Tgoutn of the outflow exhaust gas temperature and the actual measurement value Tgout.

  Next, in step S406, an integrated value ΣΔTgoutd of the outflow exhaust gas temperature difference is calculated.

  In this flow, if a negative determination is made in step S306, the processes in steps S403 to S406 are executed again.

  In this flow, in step S408, the temperature Tgoutn of the exhaust gas when the filter 10 is assumed to be normal is estimated. Here, the temperature Tgoutn of the outflow exhaust gas is the temperature of the outflow exhaust gas when the exhaust passage is switched to the exhaust passage side, the temperature of the filter 10, the flow rate of the inflowing exhaust, and the time when the exhaust passage is switched. It is estimated based on the elapsed time of.

  Next, in step S409, the temperature Tgout of the outflow exhaust gas is detected. At this time, the temperature Tgout of the outflow exhaust gas is detected by the downstream temperature sensor 14.

  Next, in step S410, the outflow exhaust gas temperature difference ΔTgoutu is calculated based on the estimated value Tgoutn of the outflow exhaust gas and the measured value Tgout.

  Next, in step S411, an integrated value ΣΔTgoutu of the outflow exhaust gas temperature difference is calculated.

  In this flow, when a negative determination is made in step S311, the processes in steps S408 to S411 are executed again.

  In step S412, it is determined whether or not the integrated value ΣΔTgoutd of the outflow exhaust gas temperature difference during the temperature decrease period Δtd is smaller than a predetermined temperature difference integrated amount ΣΔTgout1. The predetermined temperature difference integrated amount ΣΔTgout1 is stored in the ECU 20 in advance.

  If an affirmative determination is made in step S412, the process of step S413 is executed. On the other hand, if a negative determination is made in step S412, the process of step S315 is executed.

  In step S413, the integrated value ΣΔTgioutu of the outflow exhaust gas temperature difference from when the exhaust passage is switched to the exhaust passage side in step S307 until the determination time Δtj elapses is a predetermined temperature difference integrated amount Σ. It is determined whether or not it is smaller than ΔTgout2. The predetermined temperature difference integrated amount ΣΔTgout2 is stored in the ECU 20 in advance.

  If an affirmative determination is made in step S413, the process of step S314 is executed. On the other hand, if a negative determination is made in step S413, the process of step S315 is executed.

(Correspondence between components according to the present invention and this embodiment)
In this embodiment, the ECU 20 that executes steps S412, S413, and S314 in the above flow corresponds to the “determination means” according to the present invention.

(Modification)
In the filter abnormality determination method described above, the filter 10 is determined to be abnormal when both the integrated values ΣΔTgoutd and ΣΔTgoutu of the outflow exhaust gas temperature difference are smaller than the respective threshold values. However, each threshold value may be set so that the filter 10 can be determined to be abnormal when at least one of the integrated values ΣΔTgoutd and ΣΔTgoutu of the outflow exhaust gas temperature difference is smaller than the threshold value.

  Further, it may be determined whether or not the filter 10 is abnormal based on the sum of the integrated value ΣΔTgoutd and ΣΔTgoutu of the outflow exhaust gas temperature difference.

  Also in the filter abnormality determination method described above, the temperature decrease period ΔTd may be made variable as in the first embodiment.

  In this case, there is a possibility that the exhaust flow path is switched to the exhaust passage side while the temperature Tgout of the outflow exhaust gas is decreasing. For this reason, the temperature Tgout of the outflow exhaust gas at the time of switching the exhaust gas flow path to the exhaust passage side may vary depending on the timing. Therefore, the threshold value for determining whether the filter 10 is abnormal (ΣΔTgout2 in the case of the above flow) is changed according to the temperature Tgout of the outflow exhaust gas at the time of switching the exhaust flow path to the exhaust passage side. Also good.

  Also in the present embodiment, as in the modification of the first embodiment, based on the exhaust gas temperature difference at a predetermined timing during the temperature drop period and the exhaust gas temperature difference at a predetermined timing during the determination period. An abnormality determination of the filter 10 can also be performed.

  Also in the present embodiment, the configuration according to each modification of the first embodiment can be employed.

The figure which shows schematic structure of the internal combustion engine which concerns on 1st Example, and its intake / exhaust system. The time chart which shows transition of the temperature of inflow exhaust gas, and the temperature of outflow exhaust gas when the flow path of exhaust_gas | exhaustion is switched to the subchannel | path side by the switching valve. The flowchart which shows the flow of the abnormality determination of the filter which concerns on a 1st Example. The figure which shows schematic structure of the subpassage vicinity of the exhaust passage which concerns on the 1st modification of a 1st Example. The figure which shows schematic structure of the subpassage vicinity of the exhaust passage which concerns on the 2nd modification of a 1st Example. The figure which shows schematic structure of the subpassage vicinity of the exhaust passage which concerns on the 3rd modification of a 1st Example. The figure which shows schematic structure of the exhaust passage which concerns on the 4th modification of a 1st Example. The flowchart which shows the flow of the abnormality determination of the filter which concerns on a 2nd Example. The flowchart which shows the flow of the filter abnormality determination which concerns on a 3rd Example. The flowchart which shows the flow of the abnormality determination of the filter which concerns on 4th Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine 2 ... Cylinder 3 ... Fuel injection valve 4 ... Intake passage 5 ... Intake manifold 6 ... Exhaust passage 7 ... Exhaust manifold 8 ... Turbocharger 8a Compressor housing 8b Turbine housing 9 Oxidation catalyst 10 Particulate filter 11 Air flow meter 12 Throttle valve 13 Upstream temperature sensor 14 Downstream temperature sensor 15 Sub passage 16 ..Switching valve 20
21 .. Cooler

Claims (12)

A system for determining an abnormality of a particulate filter provided in an exhaust passage of an internal combustion engine,
Temperature changing means for changing the temperature of the exhaust gas without changing the flow rate of the exhaust gas flowing into the particulate filter;
Based on the change in the temperature of the exhaust gas flowing out from the particulate filter when the temperature of the exhaust gas is lowered without decreasing the flow rate of the exhaust gas flowing into the particulate filter by the temperature changing means, An abnormality determination system for a particulate filter, comprising: determination means for determining abnormality.   The temperature of the exhaust gas flowing into the particulate filter and the particulate when the determining means reduces the temperature of the exhaust gas without reducing the flow rate of the exhaust gas flowing into the particulate filter by the temperature changing means. 2. The particulate filter abnormality determination system according to claim 1, wherein abnormality of the particulate filter is determined based on a difference from a temperature of the exhaust gas flowing out from the filter.   The temperature of the exhaust gas flowing into the particulate filter and the particulate when the determining means reduces the temperature of the exhaust gas without reducing the flow rate of the exhaust gas flowing into the particulate filter by the temperature changing means. The particulate filter is determined to be abnormal when the integrated value during a predetermined period of the difference from the temperature of the exhaust gas flowing out from the filter is smaller than a predetermined temperature difference integrated amount. Particulate filter abnormality judgment system.   An estimated value of the temperature of the exhaust gas flowing out from the particulate filter when the determining means reduces the temperature of the exhaust gas without reducing the flow rate of the exhaust gas flowing into the particulate filter by the temperature changing means; The particulate filter abnormality determination system according to claim 1, wherein abnormality of the particulate filter is determined based on a difference from an actual measurement value.   An estimated value of the temperature of the exhaust gas flowing out from the particulate filter when the determining means reduces the temperature of the exhaust gas without reducing the flow rate of the exhaust gas flowing into the particulate filter by the temperature changing means; 5. The particulate filter according to claim 4, wherein the particulate filter is determined to be abnormal when an integrated value in a predetermined period of a difference from the actually measured value is larger than a predetermined temperature difference integrated amount. Abnormality judgment system. A setting means for setting a length of a period during which the temperature of the exhaust gas flowing into the particulate filter is lowered by the temperature changing means in order to determine abnormality of the particulate filter by the determining means;
The length of the period is shortened as the temperature decrease amount of the exhaust gas when the setting device decreases the temperature of the exhaust gas flowing into the particulate filter by the exhaust gas temperature changing device is larger. Item 6. The particulate filter abnormality determination system according to any one of Items 1 to 5. The length of the period set by the setting means is set as a period until the integrated value of the flow rate of the exhaust gas flowing into the particulate filter reaches a predetermined flow rate integrated amount,
The setting unit decreases the predetermined integrated flow rate as the temperature decrease amount of the exhaust gas when the temperature of the exhaust gas flowing into the particulate filter is decreased by the exhaust gas temperature changing unit is larger. The particulate filter abnormality determination system according to claim 6. The temperature changing means is
One end and the other end are connected to the exhaust passage on the upstream side of the particulate filter, and the sub passage is longer than the length from the connection portion of the one end to the connection portion of the other end in the exhaust passage;
Switching means for switching whether to circulate the exhaust gas in the sub-passage,
The particulate filter abnormality determination system according to any one of claims 1 to 7, wherein the temperature of the exhaust gas flowing into the particulate filter is lowered by causing the exhaust gas to flow through the sub-passage. The temperature changing means is
A sub-passage having one end and the other end connected to an exhaust passage upstream of the particulate filter;
A cooler provided in the sub-passage for cooling the exhaust gas flowing through the sub-passage;
Switching means for switching whether to circulate the exhaust gas in the sub-passage,
The particulate filter abnormality determination system according to any one of claims 1 to 7, wherein the temperature of the exhaust gas flowing into the particulate filter is lowered by causing the exhaust gas to flow through the sub-passage. A catalyst having an oxidation function is provided in the exhaust passage upstream of the particulate filter,
The temperature changing means is
A sub-passage having one end and the other end connected to an exhaust passage upstream of the particulate filter and formed to bypass the catalyst;
Switching means for switching whether to circulate the exhaust gas in the sub-passage,
The particulate filter abnormality determination system according to any one of claims 1 to 7, wherein the temperature of the exhaust gas flowing into the particulate filter is lowered by causing the exhaust gas to flow through the sub-passage. The temperature changing means is
A cooler that is provided in the exhaust passage upstream of the particulate filter and that cools the exhaust flowing through the exhaust passage;
The particulate filter abnormality determination system according to claim 1, wherein the temperature of the exhaust gas flowing into the particulate filter is lowered by the cooler.   In addition to the change in the temperature of the exhaust gas flowing out from the particulate filter, when the determining means reduces the temperature of the exhaust gas without reducing the flow rate of the exhaust gas flowing into the particulate filter by the temperature changing device. The particulate filter is based on the change in the temperature of the exhaust gas flowing out from the particulate filter when the temperature of the exhaust gas is raised by the temperature changing means from the state in which the temperature of the exhaust gas flowing into the particulate filter is lowered. The abnormality determination system for a particulate filter according to any one of claims 1 to 11, wherein an abnormality is determined.

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