JP2022112267A - Regeneration control device - Google Patents

Abstract

To provide a regeneration control device capable of securely suppressing damage of a filter.SOLUTION: In a regeneration control device, a filter trapping particulate matters included in exhaust gas is disposed in an exhaust pipe, and the filter is regenerated by controlling a heating section heating the filter. The regeneration control device includes: a determination section acquiring each of trap amount of the particulate matters trapped by the filter and differential pressure between the upstream side and the downstream side of the filter and determining whether or not deviation of the trap amount of the particulate matters by the filter is larger than a predetermined trap state on the basis of the trap amount of the particulate matters and the differential pressure; and a regeneration control section controlling the heating section so as to more slowly increase a heating temperature of the filter compared to the predetermined trap state, when the determination section determines that the deviation of the trap amount is large.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a playback control device.

2. Description of the Related Art Conventionally, in a vehicle such as a commercial vehicle, a filter for capturing particulate matter contained in exhaust gas is arranged in an exhaust pipe, and a regeneration control device heats the filter to control regeneration processing. has been put into practical use. Here, if the particulate matter is trapped in the filter in a partially biased state, the filter may be damaged when the filter is regenerated.

Therefore, as a technique for suppressing filter damage during regeneration processing, for example, Patent Literature 1 discloses an exhaust gas purification method that reliably prevents erosion of the filter and realizes good regeneration. In this method, by detecting the correct maximum filter temperature during regeneration and feedback-controlling the regeneration timing of the filter, the amount of heat generated during regeneration is prevented from increasing, so it is possible to suppress the erosion of the filter. .

JP-A-8-218847

However, the method of Patent Literature 1 estimates the bias in the amount of particulate matter captured by the filter based on the structure of the filter, and does not estimate it based on actual measurements. For this reason, it has been difficult to accurately estimate the bias in the amount of particulate matter captured by the filter, and to reliably suppress breakage of the filter in the regeneration process.

An object of the present disclosure is to provide a regeneration control device that reliably suppresses filter breakage.

A regeneration control device according to the present disclosure is a regeneration control device in which a filter that captures particulate matter contained in exhaust gas is arranged in an exhaust pipe, and that controls a heating unit that heats the filter to perform regeneration processing on the filter, The trapped amount of particulate matter trapped by the filter and the differential pressure between the upstream and downstream sides of the filter are obtained, respectively, and based on the trapped amount of particulate matter and the differential pressure, the amount of particulate matter trapped by the filter is calculated. a determining unit for determining whether the bias is greater than a predetermined trapping state; and a regeneration control section for controlling the heating section.

According to the present disclosure, it is possible to reliably suppress damage to the filter.

1 is a diagram showing a configuration of a vehicle provided with a regeneration control device according to Embodiment 1 of the present disclosure; FIG. 4 is a flow chart showing the operation of Embodiment 1. FIG. FIG. 4 is a diagram showing how more particulate matter is trapped in the outer peripheral portion of the filter than in the central portion; FIG. 4 is a diagram showing how particulate matter is locally deposited on the upstream side of a filter; FIG. 10 is a diagram showing how particulate matter is locally deposited on the downstream side of a filter; 4 is a graph showing changes in differential pressure with respect to the trapped amount of particulate matter.

Hereinafter, embodiments according to the present disclosure will be described based on the accompanying drawings.

(Embodiment 1)
FIG. 1 shows the configuration of a vehicle equipped with a regeneration control device according to Embodiment 1 of the present disclosure. The vehicle has an internal combustion engine 1 , an exhaust pipe 2 , an internal combustion engine control section 3 and a purification device 4 . Examples of vehicles include commercial vehicles such as trucks.

The internal combustion engine 1 is for driving a vehicle, and is composed of, for example, a so-called four-stroke engine that repeats four strokes of an intake stroke, a compression stroke, an expansion stroke and an exhaust stroke. Examples of the internal combustion engine 1 include a diesel engine.

The exhaust pipe 2 is arranged so as to extend from an exhaust port of the internal combustion engine 1 to the outside, and is a flow path through which exhaust gas discharged from the internal combustion engine 1 is discharged to the outside.

The internal combustion engine control unit 3 controls the internal combustion engine 1 and is connected to the regeneration control devices 11 of the internal combustion engine 1 and the purification device 4, respectively. The internal combustion engine control unit 3 controls, for example, the flow rate of exhaust gas flowing through the exhaust pipe 2, the injection amount of fuel, the engine speed, and the like.

The purification device 4 has an oxidation catalyst 5 , a filter 6 , temperature sensors 7 a and 7 b , a differential pressure sensor 8 , a valve 9 , an injector 10 and a regeneration control device 11 .

The oxidation catalyst 5 is arranged in the exhaust pipe 2 and oxidizes and purifies unburned fuel such as hydrocarbons and carbon monoxide contained in the exhaust gas. Further, the oxidation catalyst 5 oxidizes the fuel injected from the internal combustion engine 1 and the injector 10, thereby heating the exhaust gas to a high temperature with the reaction heat. The oxidation catalyst 5 can be made of, for example, platinum and cerium oxide.

The filter 6 is arranged downstream of the oxidation catalyst 5 in the exhaust pipe 2 and traps particulate matter such as soot components contained in the exhaust gas. The filter 6 can be of a so-called wall-flow type, in which cells made of porous ceramics such as cordierite and silicon carbide are arranged so that inlets and outlets are alternately closed. Examples of the filter 6 include DPF (Diesel Particulate Filter) and CSF (Catalyzed Soot Filter).

The temperature sensors 7a and 7b detect the temperature of the exhaust gas flowing through the exhaust pipe 2, and are arranged in the exhaust pipe 2 so as to sandwich the filter 6 therebetween. Specifically, the temperature sensor 7 a is arranged upstream of the filter 6 in the flow direction of the exhaust gas, and detects the temperature of the exhaust gas flowing into the filter 6 . The temperature sensor 7 b is arranged downstream of the filter 6 in the flow direction of the exhaust gas, and detects the temperature of the exhaust gas flowing out of the filter 6 .

A differential pressure sensor 8 is arranged in the exhaust pipe 2 and detects a differential pressure between the upstream side and the downstream side of the filter 6 .

The valve 9 adjusts the degree of opening of the exhaust pipe 2 and is rotatably arranged on the upstream side of the oxidation catalyst 5 in the exhaust pipe 2 . The valve 9 can consist, for example, of an exhaust throttle valve.

The injector 10 is arranged between the valve 9 and the oxidation catalyst 5 in the exhaust pipe 2 and injects fuel into the exhaust pipe 2 to supply unburned fuel to the oxidation catalyst 5 .
Note that the internal combustion engine 1, the oxidation catalyst 5, the valve 9, and the injector 10 have a function of heating the filter 6, and constitute a heating section in the present disclosure.

The regeneration control device 11 controls regeneration processing of the filter 6 and has a determination section 12 and a regeneration control section 13 . The determination unit 12 and the regeneration control unit 13 are each connected to the internal combustion engine control unit 3 . Also, the differential pressure sensor 8 is connected to the determination section 12 , and the determination section 12 is connected to the regeneration control section 13 . Also, the temperature sensors 7 a and 7 b are connected to the reproduction control section 13 . Furthermore, a regeneration control unit 13 is connected to the valve 9 and the injector 10 .

The determination unit 12 inputs the exhaust gas flow rate, the fuel injection amount, and the like from the internal combustion engine control unit 3, and calculates the amount of particulate matter trapped by the filter 6 based on the input values. The determination unit 12 also receives the differential pressure between the upstream side and the downstream side of the filter 6 from the differential pressure sensor 8 . Based on the captured amount of particulate matter and the differential pressure of the filter 6 thus acquired, the determination unit 12 determines whether the deviation of the captured amount of particulate matter in the filter 6 is greater than a predetermined captured state. determine whether

Here, the bias in the trapped amount of particulate matter indicates a state in which the trapped amount of particulate matter in the filter 6 partially differs by a predetermined threshold value or more.
Further, the predetermined captured state may be, for example, a state in which particulate matter is captured in the filter 6 substantially uniformly.

The regeneration control unit 13 regenerates the filter 6 by controlling the oxidation catalyst 5 via the internal combustion engine 1 , the valve 9 and the injector 10 based on the determination result of the determination unit 12 . Specifically, when the judgment unit 12 judges that the imbalance in the trapped amount is greater than the predetermined trapped state, the regeneration control unit 13 controls the heating temperature of the filter 6 to rise more moderately than the predetermined trapped amount. to control the reaction of the oxidation catalyst 5. On the other hand, when the determination unit 12 determines that the bias in the trapped amount is equal to or less than the predetermined trapped state, the regeneration control unit 13 adjusts the heating temperature of the filter 6 at a predetermined reference speed (reference speed). The reaction of the oxidation catalyst 5 is controlled so that the increases. The reference speed is set to a value that does not affect the function of the purifier 4 by an experimental or computational method.

The functions of the internal combustion engine control unit 3 and the regeneration control device 11 can also be realized by a computer program. For example, a reading device of a computer reads a program for realizing the functions of the internal combustion engine control unit 3 and the reproduction control device 11 from a recording medium, and stores the program in a storage device. Then, the CPU (Central Processing Unit) copies the program stored in the storage device to the RAM (Random Access Memory), sequentially reads out the instructions included in the program from the RAM and executes them, so that the internal combustion engine control unit 3 and the functions of the playback control device 11 can be realized.

Next, the operation of this embodiment will be described with reference to the flowchart of FIG.

First, as shown in FIG. 1, when the internal combustion engine control unit 3 controls the internal combustion engine 1 and the vehicle runs, the exhaust gas generated in the internal combustion engine 1 flows through the exhaust pipe 2 and is discharged to the outside. . At this time, the particulate matter contained in the exhaust gas is captured by the filter 6 as the exhaust gas passes through the filter 6 .

In this way, when the particulate matter is captured by the filter 6, the differential pressure between the upstream side and the downstream side of the filter 6 increases as the amount of captured particulate matter increases. The differential pressure of the filter 6 is sequentially detected by the differential pressure sensor 8 and the detected values are output from the differential pressure sensor 8 to the determination section 12 . Further, values such as the flow rate of exhaust gas flowing through the exhaust pipe 2 and the injection amount of fuel to the internal combustion engine 1 are output from the internal combustion engine control unit 3 to the determination unit 12 .

When the differential pressure detected by the differential pressure sensor 8 is input, the determination unit 12 determines in step S1 whether or not the differential pressure is equal to or greater than a predetermined value. Here, the predetermined value can be set, for example, based on the differential pressure at which a specified amount of particulate matter is captured by the filter 6 and regeneration processing is required.

If the differential pressure is less than the predetermined value, the determination unit 12 determines that regeneration processing of the filter 6 is unnecessary, and repeats the determination until the differential pressure reaches the predetermined value.
On the other hand, the determination unit 12 determines that regeneration processing of the filter 6 is necessary when the differential pressure is equal to or greater than the predetermined value.

Note that the determination unit 12 only needs to be able to determine whether the filter 6 needs to be regenerated, and is not limited to determination based on the differential pressure. For example, the determination unit 12 calculates the amount of particulate matter trapped by the filter 6 based on the flow rate of exhaust gas and the injection amount of fuel output from the internal combustion engine control unit 3, and Based on this, it is also possible to determine whether or not the filter 6 needs to be regenerated.

Here, if the filter 6 is regenerated in the same manner regardless of the particulate matter capture state of the filter 6, the filter 6 may be damaged. Specifically, when the amount of particulate matter captured by the filter 6 is highly uneven, if the heating temperature of the filter 6 is raised at the same speed as when the particulate matter is uniformly captured by the filter 6, the filter 6 may have a large temperature difference.

For example, as shown in FIG. 3, more particulate matter may be trapped in the outer peripheral portion 6a of the filter 6 than in the central portion 6b. Since the temperature of the outer peripheral portion 6a of the filter 6 tends to be lower than that of the central portion 6b in the regeneration process, the unburned residue of the particulate matter tends to accumulate on the outer peripheral portion 6a, thereby trapping the particulate matter in the outer peripheral portion 6a. Volume may increase. When the filter 6 is heated in such a biased trapping state, the outer peripheral portion 6a of the filter 6, which traps a large amount of particulate matter, rises in temperature slower than the central portion 6b. Therefore, during the period until the particulate matter P begins to burn (the period during which the temperature is raised to the combustion temperature), the temperature of the outer peripheral portion 6a of the filter 6 becomes lower than that of the central portion 6b, resulting in a large temperature difference in the filter 6. will occur.

Further, as shown in FIG. 4 , the particulate matter P trapped in the filter 6 collapses, and the particulate matter P locally accumulates on the upstream side of the filter 6 in the flow direction of the exhaust gas. In some cases, more particulate matter P is trapped on the upstream side than on the downstream side. If the filter 6 is heated in such a biased trapping state, a difference in speed of temperature rise occurs between the upstream side and the downstream side of the filter 6 , resulting in a large temperature difference in the filter 6 .

Furthermore, as shown in FIG. 5, the particulate matter P may be locally deposited downstream of the filter 6 in the flow direction of the exhaust gas. For example, when the filter 6 is placed vertically, that is, when the cells of the filter 6 are arranged so as to extend in the vertical direction, the particulate matter P captured by the filter 6 may collapse, and may become locally trapped on the downstream side of the filter 6. deposits may occur. If the filter 6 is heated in such a biased trapping state, a difference in speed of temperature rise occurs between the upstream side and the downstream side of the filter 6 , resulting in a large temperature difference in the filter 6 .

When a large temperature difference occurs in the filter 6 in this manner, the filter 6 may be damaged, such as cracking due to thermal stress. If the filter 6 is damaged, for example, the particulate matter trapping efficiency will be reduced.

Therefore, when the determining unit 12 determines in step S1 that the differential pressure is equal to or greater than the predetermined value, that is, determines that the regeneration process of the filter 6 is necessary, the process proceeds to step S2, and the amount of particulate matter captured in the filter 6 is large.

Specifically, the determination unit 12 calculates the amount of particulate matter trapped by the filter 6 based on the flow rate of the exhaust gas output from the internal combustion engine control unit 3, the injection amount of fuel, and the like. As shown in FIG. 6, in the trapping states S1 and S2 in which the amount of particulate matter trapped in the filter 6 is uneven, compared to the trapping state S0 in which the filter 6 traps the particulate matter almost uniformly, The change in differential pressure with respect to the trapped amount of material shows different values.

Here, the capture state S1 includes a state in which the amount of particulate matter captured in the filter 6 is biased toward the outer peripheral portion 6a compared to the central portion 6b (capture state in FIG. 3), and a state in which the amount of particulate matter captured in the filter 6 is concentrated on the downstream side compared to the upstream side. The highly biased state (acquisition state of FIG. 5) is shown. In this trapping state S1, the amount of particulate matter trapped in the outer peripheral portion 6a of the filter 6 is greater than in the trapping state S0, while the amount of particulate matter trapped in the central portion 6b of the filter 6 is smaller than in the trapping state S0. . In addition, the amount of particulate matter trapped on the downstream side of the filter 6 increases from that in the trapped state S0, while the amount of particulate matter trapped on the upstream side of the filter 6 decreases from that in the trapped state S0. Therefore, the change in differential pressure in the trapped state S1 shows a lower value than in the trapped state S0.

Also, the trapping state S2 indicates a state (trapping state in FIG. 4) in which the amount of particulate matter trapped in the filter 6 is more biased toward the upstream side than toward the downstream side. In this trapping state S2, particulate matter is trapped on the upstream side of the filter 6 so as to block the downstream side, and the amount of particulate matter trapped on the upstream side is greater than that in the trapping state S0. Therefore, the change in differential pressure in the trapped state S2 indicates a higher value than in the trapped state S0.

Therefore, based on the calculated amount of trapped particulate matter and the differential pressure detected by the differential pressure sensor 8, the determining unit 12 determines the amount of particulate matter trapped by the filter 6 that has been set in advance. It is determined whether or not it is greater than state S0.

For example, the determination unit 12 obtains in advance, through experiments or simulations, the differential pressure when the amount of particulate matter trapped in the trapped state S0 is a predetermined value. The determination unit 12 compares the pre-obtained differential pressure in the trapped state S0 with the differential pressure detected by the differential pressure sensor 8 when the amount of trapped particulate matter reaches a predetermined value.

When the differential pressure detected by the differential pressure sensor 8 is smaller than a predetermined threshold with respect to the differential pressure in the trapping state S0, the determination unit 12 determines that the trapping state S1 is in which the bias in the amount of trapped particulate matter is large. do. Further, when the differential pressure detected by the differential pressure sensor 8 is larger than a predetermined threshold with respect to the differential pressure in the trapping state S0, the determination unit 12 determines that the trapping state S2 in which the bias in the amount of particulate matter trapped is large. I judge. Note that when the differential pressure detected by the differential pressure sensor 8 is within the range of a predetermined threshold with respect to the differential pressure in the trapped state S0, the determination unit 12 determines that the bias in the trapped amount of particulate matter is small. I judge.

As described above, since the determination unit 12 determines based on the amount of particulate matter captured by the filter 6 and the differential pressure detected by the differential pressure sensor 8, the amount of particulate matter captured by the filter 6 can be accurately determined.

In addition, since the determining unit 12 determines that the trapped state S1 is present when the differential pressure detected by the differential pressure sensor 8 is smaller than the preset trapped state S0 differential pressure, the trapped state S1 can be accurately distinguished. can be determined separately.

Furthermore, since the determination unit 12 determines that the trapped state S2 is present when the differential pressure detected by the differential pressure sensor 8 is greater than the preset trapped state S0 differential pressure, the trapped state S2 can be accurately distinguished. can be determined separately.

At this time, the determination unit 12 acquires the captured amount of particulate matter captured by the filter 6 and the differential pressure detected by the differential pressure sensor 8 over time, and detects the particulate matter as shown in FIG. It is also possible to calculate the change in differential pressure with respect to the amount of Thereby, the determining unit 12 can determine the deviation of the captured amount of particulate matter based on the change in differential pressure with respect to the calculated captured amount of particulate matter. For example, the determination unit 12 determines the trapping states S0, S1, and S2 based on the slope of the change in the differential pressure with respect to the trapped amount of particulate matter. As a result, the determination unit 12 can more accurately determine the bias in the amount of trapped particulate matter.

The result determined in this manner is output from the determination unit 12 to the reproduction control unit 13 .

When the judgment unit 12 judges that the bias in the amount of particulate matter trapped is small, the regeneration control unit 13 proceeds to step S3, where the filter is operated at a reference speed preset corresponding to the trapping state S0. The reaction of the oxidation catalyst 5 is controlled via the internal combustion engine 1, valve 9 and injector 10 so that the heating temperature of 6 rises.

As a result, fuel is injected from the internal combustion engine 1 and the injector 10, and the injected fuel is oxidized by the oxidation catalyst 5, whereby the exhaust gas is heated by the reaction heat. Further, the temperature of the exhaust gas is further increased by narrowing the exhaust pipe 2 with the valve 9 . In this way, the temperature of the exhaust gas rises and the exhaust gas passes through the filter 6, so that the heating temperature of the filter 6 rises.

Based on the values detected by the temperature sensors 7a and 7b, the regeneration control unit 13 controls the heating temperature of the filter 6 to rise to a preset combustion temperature at a reference speed. When the heating temperature of the filter 6 reaches a predetermined combustion temperature, the combustion temperature is maintained for a predetermined period of time, so that the particulate matter trapped in the filter 6 is burned and the regeneration process of the filter 6 is completed.

On the other hand, if the judgment unit 12 judges that the trapping state is S1 or S2, in which the amount of particulate matter trapped is largely unbalanced, the regeneration control unit 13 proceeds to step S4, where the speed is slower than the reference speed, that is, in the trapping state. The reaction of the oxidation catalyst 5 is controlled via the internal combustion engine 1, the valve 9 and the injector 10 so that the heating temperature of the filter 6 rises more slowly than S0. For example, the regeneration control unit 13 can perform control so that the heating temperature of the filter 6 gently rises from the trapped state S0 at a constant speed. At this time, the regeneration control unit 13 can moderate the rise in the heating temperature of the filter 6 by, for example, reducing the amount of fuel injected from the internal combustion engine 1 and the injector 10 from the trapped state S0.

As a result, the temperature difference in the filter 6 can be restricted to be less than the predetermined threshold over the period in which the heating temperature is increased, and damage to the filter 6 can be reliably suppressed.

Here, the filter 6 generally has a higher heating temperature than other trapping states when the amount of trapped particulate matter is larger in the outer peripheral portion 6a than in the central portion 6b in the trapping state S1. A large temperature difference is likely to occur as the temperature rises, which tends to cause breakage.

Therefore, the regeneration control unit 13 performs control so that the heating temperature of the filter 6 rises more slowly when the determining unit 12 determines that the trapped state is S1, compared to when the trapped state is determined to be S2. can do. As a result, the regeneration control unit 13 can increase the heating temperature of the filter 6 at a speed corresponding to the trapping states S1 and S2, and can more reliably suppress breakage of the filter 6 .

Further, the regeneration control unit 13 determines that the amount of particulate matter trapped in the filter 6 is greater in the outer peripheral portion 6a than in the central portion 6b in the trapping state S1 based on the change in differential pressure with respect to the amount of particulate matter trapped. It is also possible to distinguish between a state and a state in which the amount of particulate matter captured by the filter 6 is greater on the downstream side than on the upstream side. As a result, when the regeneration control unit 13 determines that the trapped amount of particulate matter is larger on the downstream side than on the upstream side, the heating temperature of the filter 6 rises at the same speed as in the trapped state S2. to control. Then, when it is determined that the amount of trapped particulate matter is greater in the outer peripheral portion 6a than in the central portion 6b, the regeneration control portion 13 sets the heating temperature of the filter 6 more gently than in the trapped state S2. control to rise to As a result, damage to the filter 6 can be suppressed more reliably.

Further, the regeneration control unit 13 only needs to increase the heating temperature of the filter 6 more gently than in the trapped state S0, that is, to raise the heating temperature to a predetermined combustion temperature over a longer period of time than in the trapped state S0. It is not limited to the one that raises by height.

For example, the regeneration control unit 13 can preset a temperature of interest based on changes in the damage rate of the filter 6 with respect to the heating temperature, and control the increase in the heating temperature of the filter 6 based on the temperature of interest. Here, the temperature of interest is the temperature at which the breakage rate of the filter 6 sharply increases as the heating temperature rises, and can be set based on the material (thermal expansion coefficient, etc.) and shape of the filter 6. The regeneration control unit 13 performs control so that the heating temperature of the filter 6 after reaching the temperature of interest rises more gently than before reaching the temperature of interest. For example, from the start of heating of the filter 6 to the target temperature, the heating temperature can be increased at the same speed as in the capture state S0, and from the target temperature to the predetermined combustion temperature, the heating temperature can be increased more gently than in the capture state S0.
In this way, by rapidly increasing the heating temperature up to the target temperature at which the damage rate of the filter 6 is small, it is possible to rapidly increase the heating temperature while suppressing damage to the filter 6 .

In this manner, when the heating temperature of the filter 6 rises to the predetermined combustion temperature, the regeneration control unit 13 maintains the filter 6 at the combustion temperature for a predetermined time. As a result, the particulate matter captured by the filter 6 is burned, and the regeneration process of the filter 6 is completed.

According to the present embodiment, the imbalance in the amount of particulate matter captured by filter 6 is determined based on the amount of particulate matter captured by filter 6 and the differential pressure between the upstream side and the downstream side of filter 6. It is determined whether or not it is greater than S0, and if it is determined that the deviation of the trapped amount is large, the heating temperature of the filter 6 is raised more moderately than in the trapped state S0. As a result, the temperature difference in the filter 6 can be restricted to a small value over the period in which the heating temperature is increased, and damage to the filter 6 can be reliably suppressed.

(Embodiment 2)
A second embodiment of the present disclosure will be described below. Here, differences from the first embodiment will be mainly described, and common reference numerals will be used for common points with the first embodiment, and detailed description thereof will be omitted.

In Embodiment 1 described above, the determination unit 12 can calculate the degree of bias in the amount of particulate matter captured by the filter 6 .

For example, the determining unit 12 can calculate the degree of bias in the amount of trapped particulate matter in the filter 6 based on the change in differential pressure with respect to the amount of trapped particulate matter.

Specifically, the determination unit 12 temporally acquires the amount of particulate matter captured by the filter 6 calculated based on the flow rate of the exhaust gas, etc., and the differential pressure detected by the differential pressure sensor 8. , the change in differential pressure with respect to the amount of trapped particulate matter as shown in FIG. Then, the determination unit 12 determines the capture states S0, S1, and S2 based on the change in differential pressure with respect to the amount of particulate matter captured.

Subsequently, when the determining unit 12 determines that the trapping state S1 is present, it calculates the degree of bias in the trapped amount of particulate matter in the trapping state S1. At this time, the determining unit 12 calculates that, for example, the smaller the slope of the change in differential pressure with respect to the amount of trapped particulate matter, the greater the degree of bias in the amount of trapped particulate matter.

On the other hand, when the determining unit 12 determines that the trapped state is S2, it calculates the degree of bias in the trapped amount of particulate matter in the trapped state S2. At this time, the determining unit 12 calculates that, for example, the larger the slope of the change in differential pressure with respect to the amount of trapped particulate matter, the greater the degree of bias in the amount of trapped particulate matter.

It should be noted that the degree of bias in the captured amount of particulate matter is not limited to being calculated based only on the magnitude of the slope, but can also be calculated based on, for example, a partial change in the slope.

Subsequently, the regeneration control unit 13 performs control so that the heating temperature of the filter 6 gradually rises as the degree of imbalance in the trapped amount of particulate matter increases.
In this way, the larger the degree of bias in the amount of trapped particulate matter, that is, the more easily a large temperature difference occurs in the filter 6, the more gently the heating temperature is raised, so that damage to the filter 6 can be more reliably suppressed. .

According to the present embodiment, the regeneration control unit 13 controls the heating temperature of the filter 6 to gradually increase as the degree of bias in the trapped amount of particulate matter calculated by the determination unit 12 increases. Damage to the filter 6 can be suppressed more reliably.

(Embodiment 3)
A third embodiment of the present disclosure will be described below. Here, the points of difference from the first and second embodiments described above will be mainly described, and the points in common with the first and second embodiments described above will be described in detail using common reference numerals. omitted.

In Embodiments 1 and 2 described above, the regeneration control unit 13 performs regeneration processing by maintaining the filter 6 at the combustion temperature for a predetermined time. It is not limited to this.

For example, when the judgment unit 12 judges that the bias in the trapped amount of particulate matter is greater than the trapped state S0, the regeneration control unit 13 heats the filter 6 at a predetermined combustion temperature for a longer period of time than in the trapped state S0. can be controlled to

As a result, even if the amount of particulate matter captured by the filter 6 is largely uneven, the particulate matter can be reliably burned. Therefore, it is possible to suppress unevenness in the amount of particulate matter captured by the filter 6 after the regeneration process, and to reliably prevent the filter 6 from being damaged in the next regeneration process.

Further, the regeneration control unit 13 can lengthen the combustion time of the filter 6 as the degree of bias in the amount of particulate matter trapped by the filter 6 increases. As a result, the particulate matter captured by the filter 6 can be burned more reliably.

Furthermore, the regeneration control unit 13 can control the flow velocity of the exhaust gas so as to increase the combustion efficiency of the particulate matter. As a result, the particulate matter captured by the filter 6 can be burned more reliably.

According to the present embodiment, the regeneration control unit 13 controls to heat the filter 6 for a longer period of time than the capture state S0 when the determination unit 12 determines that the amount of particulate matter captured is highly uneven. do. As a result, unevenness in the amount of particulate matter captured by the filter 6 after the regeneration process is suppressed, and it is possible to reliably prevent the filter 6 from being damaged in the next regeneration process.

(Embodiment 4)
A fourth embodiment of the present disclosure will be described below. Here, the description will focus on the differences from the above-described Embodiments 1 to 3, and the common points with the above-described Embodiments 1 to 3 will be described in detail using common reference numerals. omitted.

In the first to third embodiments described above, the regeneration control unit 13 raises the heating temperature of the filter 6 in accordance with the values detected by the temperature sensors 7a and 7b. As long as it can be raised gently, it is not limited to this.

For example, the regeneration control unit 13 estimates the internal temperature of the filter 6 based on the upstream and downstream temperatures of the filter 6 and the bias in the trapped amount of particulate matter, and based on the estimated internal temperature of the filter 6 , the heating temperature of the filter 6 can be increased.

Specifically, a map showing changes in the internal temperature of the filter 6 in the trapping states S1 and S2 with respect to the upstream and downstream temperatures of the filter 6 is acquired in advance by experiment or simulation. The regeneration control unit 13 refers to a previously acquired map based on the upstream temperature and the downstream temperature detected by the temperature sensors 7a and 7b and the imbalance of the amount of trapped particulate matter determined by the determination unit 12. By doing so, the internal temperature of the filter 6 is estimated. Then, the regeneration control unit 13 controls so that the heating temperature of the filter 6 rises along with the estimated internal temperature of the filter 6 . As a result, damage to the filter 6 can be suppressed more reliably.

According to the present embodiment, the regeneration control unit 13 estimates the internal temperature of the filter 6 based on the upstream and downstream temperatures of the filter 6 and the bias in the trapped amount of particulate matter, and the estimated filter The heating temperature is controlled to rise based on the internal temperature of 6. Therefore, damage to the filter 6 can be suppressed more reliably.

In Embodiments 1 to 4 described above, the determination unit 12 determines whether the bias in the amount of particulate matter captured by the filter 6 is greater than the trapping state S0. is not limited to this. For example, the determination unit 12 can also determine whether the bias in the amount of particulate matter captured by the filter 6 is greater than the capture state S2.

In the first to fourth embodiments described above, the determining unit 12 determines the trapping states S1 and S2 in which the bias in the amount of particulate matter trapped in the filter 6 is greater than the trapping state S0. It suffices to determine whether or not, and the present invention is not limited to this.

Further, in Embodiments 1 to 4 above, the regeneration control device 11 is arranged in the vehicle, but it is not limited to this as long as it can control regeneration processing of the filter 6 that traps particulate matter. For example, the regeneration control device 11 can be installed in a ship, an industrial machine, or a factory where a stationary internal combustion engine is installed.

In addition, the above-described embodiments are merely examples of specific implementations of the present invention, and the technical scope of the present invention should not be construed to be limited by these. be. Thus, the invention may be embodied in various forms without departing from its spirit or essential characteristics. For example, the disclosure of the shape, number, etc. of each part described in the above embodiment is merely an example, and can be implemented with appropriate modifications.

INDUSTRIAL APPLICABILITY The regeneration control device according to the present disclosure can be used as a device for controlling regeneration processing of a filter that traps particulate matter.

REFERENCE SIGNS LIST 1 internal combustion engine 2 exhaust pipe 3 internal combustion engine control unit 4 purification device 5 oxidation catalyst 6 filter 6a outer peripheral portion 6b center portion 7a, 7b temperature sensor 8 differential pressure sensor 9 valve 10 injector 11 regeneration control device 12 determination unit 13 regeneration control unit P Particulate matter S0, S1, S2 capture state

Claims (6)

A regeneration control device in which a filter that captures particulate matter contained in exhaust gas is arranged in an exhaust pipe, and that controls a heating unit that heats the filter to regenerate the filter,
The trapped amount of the particulate matter trapped by the filter and the differential pressure between the upstream side and the downstream side of the filter are respectively acquired, and based on the trapped amount of the particulate matter and the differential pressure, the a determination unit that determines whether the bias in the amount of trapped particulate matter is greater than a predetermined trapped state;
a regeneration control unit that controls the heating unit so that the heating temperature of the filter rises more moderately than the predetermined trapping state when the determination unit determines that the bias in the trapped amount is large. Control device. The determination unit determines that the bias of the particulate matter in the filter is large when the differential pressure when the captured amount of the acquired particulate matter reaches a predetermined value is smaller than the predetermined captured state. The reproduction control device according to claim 1. The determination unit determines that the bias of the particulate matter in the filter is large when the differential pressure is greater than the predetermined capture state when the captured amount of the acquired particulate matter reaches a predetermined value. death,
When the differential pressure is determined to be less than the predetermined trapping state, the regeneration control unit reduces the heating temperature of the filter compared to when the differential pressure is determined to be greater than the predetermined trapping state. 3. The regeneration control device according to claim 2, wherein the heating unit is controlled so that the .DELTA. The regeneration control unit presets a temperature of interest based on a change in the damage rate of the filter with respect to the heating temperature, and compares the heating temperature of the filter after reaching the temperature of interest with the heating temperature of the filter before reaching the temperature of interest. 4. The regeneration control device according to any one of claims 1 to 3, wherein the heating unit is controlled so as to gently rise. The determination unit calculates a degree of bias in the amount of particulate matter captured by the filter based on a change in the differential pressure with respect to the amount of particulate matter captured,
The regeneration control device according to any one of claims 1 to 4, wherein the regeneration control unit controls the heating unit so that the heating temperature of the filter increases more slowly as the degree of bias increases. 2. The regeneration control unit controls the heating unit so as to heat the filter for a longer period of time than the predetermined capture state when the determination unit determines that the bias in the trapped amount is large. 6. The regeneration control device according to any one of 1 to 5.

Images