JP2003254045A - Regeneration device for diesel particulate filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a regeneration device for a diesel particulate filter (hereinafter referred to as 'DPF') realizing shortening of a regeneration treatment time. <P>SOLUTION: The regeneration device is provided with: the DPF attached to an exhaust system of an engine; an electric heater attached to an upstream side of the DPF and burning/removing the particulate captured by the DPF; a parameter sensor for detecting a predetermined parameter at the time of driving of the engine; a control means for memorizing a threshold value at the time of starting of generation based on a detection value of the parameter sensor and first and second setting time over a predetermined time after starting the regeneration; a temperature sensor for detecting a temperature at an upstream side of the filter; and a time measurement means for measuring an energization time to the heater. The control means energizes 100% to the heater over the first setting time based on the time measurement value of the time measurement means accompanying with the starting of the regeneration of the DPF based on the detection value of the parameter sensor. After the first setting time is passed, the energization to the heater is variably controlled over the second setting time based on the time measurement value of the time measurement means and the measurement value of the temperature sensor. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diesel particulate filter regenerator mounted on an exhaust system of a diesel engine.

[0002]

2. Description of the Related Art Exhaust gas emitted from a diesel engine contains a large amount of particulates (fine particle components such as carbon particles).
It is said that it is essential to remove the particulates when purifying the exhaust gas of the "engine".

Therefore, as disclosed in Japanese Patent Application Laid-Open No. 11-125109, a diesel particulate filter device (hereinafter referred to as "DPF device") has recently been attached to an exhaust system of an engine to purify exhaust gas. ing.
As a DPF device of this type, the above-mentioned JP-A-11-
As shown in Japanese Patent No. 125109 or FIG. 9, an exhaust pipe 1 connected to an exhaust manifold is branched into a plurality of branch pipes 3 and 5, and an exhaust gas flow path of both branch pipes 3 and 5 is opened and closed at the branch portion 7. An on-off switching valve 9 is installed, and a diesel particulate filter (hereinafter,
It is known that the “DPF”) 11 and 13 are mounted, and the exhaust gas flow paths of the branch pipes 3 and 5 are alternately opened and closed by the control of the open / close switching valve 9 by the controller to remove the particulates in the exhaust gas G. It is collected by DPF11,13.

Further, as the collection of particulates progresses,
Since the DPFs 11 and 13 are clogged to increase the flow path resistance, electric heaters (hereinafter referred to as “heaters”) 19 and 21 are installed in the casings 15 and 17 of the DPFs 11 and 13 on the upstream side of the DPFs 11 and 13. As shown in FIG. 9, for example, when the switching valve 9 closes the branch pipe 3 and opens the branch pipe 5 in response to a command from the controller, the exhaust gas G discharged from the engine flows down the exhaust pipe 1 and the branch pipe 5. Then, the particulates in the exhaust gas G are collected by the DPF 13, and in this state, the heater 19 on the DPF 11 side is activated, and D
The particulates in the PF 11 are burned and removed to remove the DPF.
11 are reproduced.

After regeneration of the DPF 11, the DPF 13
When the amount of particulates collected by the filter increases and the filter pressure loss increases, the controller switches the open / close switching valve 9 to cause the exhaust gas G to flow down the branch pipe 3, and the particulates in the exhaust gas G are collected by the DPF 11. , The heater 21 on the DPF 13 side is operated to regenerate the DPF 13. The branch pipes 3 and 5 are connected to the DPFs 11 and 13.
The merging portion 23 on the downstream side of the merging portion is connected to a tail pipe (downstream side exhaust pipe) 25.

Various methods have been conventionally proposed as a method for determining the regeneration start time of the DPF. For example, in the DPF regeneration device disclosed in Japanese Patent Laid-Open No. 9-13951, the DPF is considered from the relationship between the exhaust flow rate and the filter pressure loss. In the conventional example of Japanese Patent Laid-Open No. 8-277710, the regeneration start time of the DPF is determined from the relationship between the exhaust pressure of the exhaust manifold or its vicinity and the pressure detected at the DPF inlet. There is.

By the way, in general, if the DPF is regenerated when the particulates are excessively accumulated, the filter temperature becomes too high and the DPF is cracked or melted, and the particulate collection amount is small. It has been pointed out that reproduction causes defective reproduction, increases in the frequency of energization of the heater, and increases power consumption. Also,
Since a high temperature of 600 ° C. or higher is required to ignite the particulates, it is necessary to heat the filter so as to keep the filter temperature at an appropriate temperature during regeneration so that the temperature does not become too high.

Therefore, in the DPF device 27, the DPF
Temperature sensors 29 and 31 are mounted near the upstream end surfaces 11a and 13a of the sensors 11 and 13, respectively, and the controller detects the temperature sensors 29 and 31 after starting regeneration (after starting heater energization) as shown in FIGS. Based on the value, the heaters 19 and 21 are energized 100% until the temperature upstream of the filter (ambient temperature before the filter) reaches the set temperature, and when the detected temperature reaches the set temperature, the temperature detected by the temperature sensors 29 and 31 is detected. In accordance with the above, the power supply to the heaters 19 and 21 is variably controlled, and the filter upstream temperature is maintained at a substantially constant set temperature until a predetermined set time until the end of regeneration.

[0009]

However, in the above-mentioned conventional DPF device 27, as shown in FIG. 11, the DPF 11 is heated by the heaters 19 and 21 immediately after the regeneration is started.
The temperature on the upstream side (front part) of 13 rapidly rises, but D
It is the actual situation that it takes time to reach the sufficient temperature required for the regeneration process inside the PFs 11 and 13 and on the downstream side (rear part).

Even when the temperature detected by the temperature sensors 29 and 31 reaches the set temperature, the temperature inside the DPFs 11 and 13 often does not reach a sufficient temperature for the regeneration process. If the energization control to the heaters 19 and 21 is started assuming that the temperature has reached the set temperature, the DPF
There is also a possibility that reproduction failure may occur inside 11 and 13 or on the downstream side.

The present invention has been devised in view of such circumstances, and an object of the present invention is to provide a DPF regenerating apparatus in which regeneration failure is eliminated while shortening the regeneration processing time.

[0012]

In order to achieve such an object, the invention according to claim 1 is a DPF mounted on an exhaust system of an engine, and is mounted on the upstream side of the DPF and collected by the DPF. A heater that burns and removes particulates,
A parameter sensor that detects a predetermined parameter when the engine is driven, and D based on a detection value of the parameter sensor
Control means for storing a threshold value for starting PF reproduction and first and second set times over a predetermined time after starting reproduction, and a DPF
Mounted on the upstream side of the filter, the temperature sensor for detecting the temperature on the upstream side of the filter, and the time measuring means for measuring the energization time to the heater are provided, and the control means controls the regeneration start of the DPF based on the detection value of the parameter sensor. Accordingly, the heater is energized 100% for the first set time based on the time measured value of the time measuring means, and after the first set time has elapsed, the second time is set based on the time measured value of the time measuring means and the measured value of the temperature sensor. It is characterized in that the heater energization is variably controlled over the set time.

According to this structure, the control means starts the regeneration of the DPF based on the detection value of the parameter sensor,
The heater is energized 100% for the first set time based on the time value of the time measuring means. Therefore, the temperature on the upstream side of the filter rises at once within the first set temperature, and the temperature of the entire DPF rapidly rises.

After the lapse of the first set time, the control means variably controls the heater energization over the second set time based on the measured value of the time measuring means and the measured value of the temperature sensor. The temperature will be maintained at a predetermined value. According to a second aspect of the present invention, in the DPF regenerator according to the first aspect, the control means controls the pulse width modulation of the heater energization for a second set time after the first set time has elapsed. According to a third aspect of the present invention, in the DPF regeneration device according to the first aspect, the control means controls ON / OFF of the heater energization for a second set time after the first set time has elapsed. It is characterized by doing.

Thus, according to these configurations, since the heater energization is controlled by the pulse width modulation control and the ON / OFF control by the control means over the second set time after the first set time has elapsed. The upstream temperature will be maintained at a predetermined value.

[0016]

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

FIG. 1 is a DPF according to claim 1 and claim 2.
In the figure, 33 is an exhaust manifold attached to the engine 35, 37 is an exhaust pipe connected to the exhaust manifold 33, and an exhaust pipe 37
A turbocharger 39 is mounted on the turbocharger 39. As is well known in the art, when exhaust gas G emitted from the engine 35 turns a turbine 39a of the turbocharger 39, a compressor 39b directly connected to the turbocharger 39 is rotated to compress compressed intake air. Are sent from the intake pipe 41 to the engine 35 via the intake manifold 43.

The exhaust system on the downstream side of the turbocharger 39 is branched into two branch pipes 45 and 47 arranged in parallel,
DPFs 49 and 51 are mounted in parallel on the branch pipes 45 and 47, respectively. The DPFs 49 and 51 are monolithic trap filters made of silicon carbide, and a large number of cells 55 that are substantially parallel to the exhaust gas flow are formed by the honeycomb partition walls 53, and the inlet and outlet of each cell 55 are alternately plugged with a blocking material 57. When the exhaust gas G flows into the adjacent cell 55 through the partition wall 53, the particulates contained in the exhaust gas G are collected by the partition wall 53.

The branch pipes 45 and 47 are respectively provided with DP
Butterfly valves 59 and 61 are mounted on the upstream side of the F49 and 51, and each of the butterfly valves 59 and 61 is connected to an actuator 6 from an air tank by electromagnetic valves 65 and 67 which operate according to a command from a controller (control means) 63, respectively.
Compressed air is supplied to each of the branch pipes 45, 47.
The exhaust gas flow paths are alternately opened and closed. Then, the branch pipes 45 and 47 join together on the downstream side of the DPFs 49 and 51, and the tail pipe (downstream exhaust pipe) 72 is open to the atmosphere.
Further, in the figure, 73 and 75 are DPF4.
DPF mounted in casings 77 and 79 of 9,51
With the heater for reproduction, the controller 63 operates both the heaters 73 and 75 via the built-in power unit. In the present embodiment, the heaters 73 and 75 use the DPFs 49 and 51.
At the time of reproducing, the reproduction start time is determined by using the following pressure loss threshold map.

That is, generally, in order to calculate the filter pressure loss of the DPF, the pressures on the upstream side and the downstream side of the DPF are detected by the pressure sensor, and the filter pressure loss is calculated from these detected values. Therefore, also in the present embodiment, the branch pipes 4 of the branch pipes 45 and 47 on the upstream side of the branch portion 81 and on the downstream side of the DPFs 49 and 51.
5, pressure sensors 83 and 85 are mounted respectively, and the upstream and downstream pressures of the DPFs 49 and 51 are detected by the respective pressure sensors 83 and 85, and the detected values Pf and Pa are set to the controller 63.
Is input.

Then, the controller 63 uses the detected values Pf and Pa to determine the DPF at the time of particulate collection.
The filter pressure loss ΔP of 49 is calculated by the following equation: ΔP = Pf−Pa. Further, in a naturally aspirated engine, the exhaust gas flow rate is generally proportional to the engine speed, and the filter pressure loss is generally proportional to the exhaust gas flow rate. Then, since the filter pressure loss increases as the amount of collected particulates in the DPF increases, it is possible to detect an increase in the amount collected in the DPF from the relationship between the engine speed and the filter pressure loss, but a turbocharger was installed. Since the exhaust gas flow rate changes depending on the engine load in the engine, it is difficult to accurately determine the regeneration start time of the DPF only by the engine speed and the filter pressure loss.

As a parameter representing the engine load, not only the engine load itself but also the boost pressure and the exhaust temperature can be mentioned. That is, when the engine is loaded,
The fuel injection amount of the engine increases and the exhaust gas flow rate increases,
As a result, the turbine of the turbocharger rotates, the boost pressure (engine intake pressure) rises, and the exhaust temperature also rises.

Therefore, not only the engine load is directly detected, but the boost pressure and the exhaust temperature are detected, which leads to the detection of the change in the engine load, and these functions as a parameter representing the engine load. Therefore, as shown in FIG. 1, in the embodiment, the intercooler 9 in which the pressure sensor 89 for detecting the boost pressure is attached to the intake pipe 41 is used.
1 is installed on the upstream side to input the detected value to the controller 63, and a rotation sensor 93 for detecting the engine speed (engine speed) is mounted on the engine 35 and the detection signal is input to the controller 63. ing.

Thus, these pressure sensors 83, 85,
89 and the rotation sensor 93 correspond to the parameter sensor according to claim 1, which detects a predetermined parameter when the engine is driven. FIG. 2 is a pressure loss threshold map in which the engine speed N is plotted on the X axis, the filter pressure loss ΔP is plotted on the Y axis, and the boost pressure is plotted on the Z axis. A three-dimensional pressure loss threshold map based on ΔP and boost pressure is preset and stored.

Then, for example, as shown in FIG. 1, the butterfly valve 61 is closed, the butterfly valve 59 is opened, and the exhaust gas G is discharged.
When the particulates inside are collected by the DPF 49, the controller 63 calculates the filter pressure loss ΔP based on the detection values of the pressure sensors 83 and 85, and the filter pressure loss ΔP.
The engine speed N detected by the rotation sensor 93 and the boost pressure detected by the pressure sensor 89 are collated, and D
When it is determined that the filter pressure loss ΔP of the PF 49 exceeds the pressure loss threshold value α of the pressure loss threshold map of FIG. 2, the butterfly valve 59 is closed and the heater 73 is operated, and at the same time, the butterfly valve 61 is opened to open the exhaust gas G. Branch pipe 4
Run down to side 7.

Therefore, thereafter, the particulates in the exhaust gas G are collected by the DPF 51, and at this time, the particulates in the DPF 49 are burned and removed by the heater 73, and the DP is discharged.
The reproduction of F49 will be achieved. The reproducing apparatus 95 according to the present embodiment has the following features when performing the reproducing process of the DPFs 49 and 51.

That is, in the memory of the controller 63, in addition to the pressure loss threshold map described above, as shown in FIG. 3, a certain predetermined time has passed from the start of energization of the heaters 73 and 75 accompanying the start of regeneration. A first set time (hereinafter referred to as “set time 1”) and a second set time from the start of reproduction to the end of reproduction (hereinafter referred to as “set time 2”) are stored in advance.

As shown in FIGS. 3 and 4, this embodiment is
The temperature required to ignite particulates is, for example, 600 ° C
Then, this 600 ° C. is set as the set temperature of FIG.
The DPF4 is set at an upper limit of 1000 ° C. which exceeds the set temperature and at which the DPFs 49 and 51 may be cracked or melted.
Based on the capacity of 9, 51, the time required for the temperature on the upstream side of the filter (ambient temperature before filter) to reach about 800 ° C. is obtained in advance, and this is set as the set time 1. Although not shown, the CPU of the controller 63 Has a built-in time measuring means such as a timer, and the controller 63 starts reproduction (heater 7
With the start of energization to 3,75), the clocking means is started and the clocked value is input.

After starting the reproduction, the controller 63 controls the heaters 73, 75 to 100 until the set time 1 is reached.
% Energized. On the other hand, the set time 2 is DP
In the time required for the regeneration of F49, 51, the temperature of the upstream side of DPF 49, 51 rapidly rises as the heaters 73, 75 are energized as shown in FIG.
Downstream, it takes time for the temperature rise for regeneration,
After that, the heat of combustion of particulates is also added, and the temperature rises rapidly.

Therefore, in this embodiment, the DPFs 49 and 51 are
The required time required for regeneration of the DPFs 49, 51 is obtained in advance based on the capacity of the controller 6, and this is set as the set time 2 for the controller 6
It is stored in the memory of 3. As shown in FIG. 1, temperature sensors 97 and 99 for detecting the upstream temperature of the filter are mounted near the upstream end faces of the DPFs 49 and 51, and the respective detection signals are input to the controller 63. Then, as shown in FIGS. 3 and 4, the controller 6
3 indicates that the heater energization is PW according to the temperature detected by the temperature sensors 97 and 99 after the set time 1 has elapsed and until the set time 2 is reached.
By performing M control (pulse width modulation control), the temperature on the upstream side of the filter is maintained near 600 ° C. which is the set temperature.
Then, after the elapse of the set time 2, the controller 63 stops the energization of the heater and ends the regeneration process.

In addition, in FIG. 1, 101 is a conventionally known exhaust brake including a butterfly valve 103 and an actuator 105, and the exhaust brake 101 is also driven and controlled by the controller 63.

Since the present embodiment is constructed in this way, the controller 63 closes the butterfly valve 61 and opens the butterfly valve 59 as shown in FIG. When flowing down, the exhaust gas G flows into the adjacent cell 55 through the partition wall 53 of the DPF 49, and the particulates in the exhaust gas G are collected by the partition wall 53. The filter pressure loss increases.

Therefore, as shown in step S1 of FIG. 5, the controller 63 takes in the engine speed N during traveling from the rotation sensor 93, and at the same time, the pressure sensors 83,
Data is taken in from 85 and 89. Then, in step S2, the controller 63 uses the calculation formula to calculate the DPF4
9 is calculated, and the filter pressure loss ΔP of the DPF 49 according to the engine speed N and the boost pressure is
It is determined whether or not the pressure loss threshold value α in the pressure loss threshold value map of FIG. 2 is exceeded, and when the calculated filter pressure loss ΔP exceeds the pressure loss threshold value α, the controller 63 proceeds to step S3. The butterfly valve 59 is closed to operate the heater 73, and at the same time, the butterfly valve 61 is opened to allow the exhaust gas G to flow down to the branch pipe 47 side.

Therefore, the exhaust gas G flowing into the branch pipe 47 side
Flows into the adjacent cell 55 through the partition 53 of the DPF 51, the particulates in the exhaust gas G are collected by the partition 53, and the particulates in the DPF 49 are burned and removed by the heater 73 to regenerate the DPF 49. However, as shown in steps S4 and S5 of FIG. 6, the controller 63 energizes the heater 73 100% after the start of regeneration until the set time 1 is reached, and the filter upstream temperature is set to 800 at the set time 1 at once. Raise to about ℃.

After the elapse of the set time 1, the controller 63 PWM-controls the energization of the heater in accordance with the temperature detected by the temperature sensor 97 (steps S6 and S7) to keep the upstream temperature of the filter near the set temperature of 600 ° C. , Set time 2
After the passage of, the controller 63 stops the heater energization and ends the regeneration processing of the DPF 49 (steps S8 and S9).

Hereinafter, the controller 63 calculates the filter pressure loss ΔP of the DPF 51 from the calculation formula, and the filter pressure loss ΔP of the DPF 51 according to the engine speed N and the boost pressure is the pressure loss in the pressure loss threshold map of FIG. When it is determined whether or not the threshold value α is exceeded, the above-described step S1 is performed.
~ Through the process of step S9, regeneration of the DPF 51, DP
The reproduction of F49 will be sequentially performed.

As described above, in this embodiment, the temperature on the upstream side of the filter suddenly rises to 8 after the regeneration is started and before the set time 1 is reached.
10 to heaters 73 and 75 so that the temperature rises to about 00 ° C.
Energize 0%, and then PW the heater energization according to the temperature detected by the temperature sensors 97 and 99 until the set time 2 elapses.
Since the M control is performed, the temperature of the entire DPF 49, 51 rises faster than that of the conventional example shown in FIG. 9 and thereafter, and as a result, the regeneration processing time can be shortened and the power consumption by the heaters 73, 75 can be reduced. It became a thing.

Further, in the present embodiment, as described above, the temperature on the upstream side of the filter is increased to 800 ° C.
As a result of accelerating the temperature rise of the PFs 49, 51 as a whole, it is possible to reduce regeneration defects inside and downstream of the DPFs 49, 51 as compared with the conventional case. Instead of the PWM control described above, as in one embodiment of claim 1 and claim 3 shown in FIG.
After the set time 1 elapses, until the set time 2 is reached, the filter upstream temperature is set as a threshold value stored in advance in the memory based on the temperatures detected by the temperature sensors 97 and 99 (for example, the above-described embodiment. Similarly, the heater energization may be controlled to be turned on / off depending on whether or not the temperature exceeds 600 ° C., and the filter upstream temperature may be maintained near the set temperature.

Thus, according to this embodiment, after the set time 1 has elapsed (steps S4 and S5), the controller 63 filters the temperature based on the temperatures detected by the temperature sensors 97 and 99 until the set time 2 is reached. It is determined whether the upstream temperature exceeds a threshold value (set temperature), and when the upstream temperature of the filter exceeds the threshold value, the heaters 73 and 75 are de-energized and fallen below the threshold value. At 100% of the time, the temperature on the upstream side of the filter is maintained near 600 ° C. which is the set temperature (steps S6, S10 to S12).

Then, after the lapse of the set time 2, the controller 63 stops the energization of the heater and ends the regeneration processing of the DPFs 49 and 51 (steps S13 and S1).
4) According to this embodiment, the intended purpose can be achieved as in the embodiment of FIGS. 1 to 6.
It should be noted that each of the above-described embodiments has two types of exhaust system for the engine 35.
The branch pipes 45 and 47 are arranged in parallel, and the branch pipe 4
The present invention is applied to a DPF device in which DPFs 49 and 51 are attached to 5 and 47, respectively. However, the number of branch pipes and DPFs attached to the branch pipes is not limited to two. It is also possible to apply the present invention to a pipe in which the branch pipes are branched, the DPFs are mounted in parallel to the respective branch pipes, and the branch pipes are joined at a joining portion on the downstream side of each DPF.

[0041]

As described above, according to the inventions according to the claims, the temperature rise of the entire DPF is accelerated as compared with the conventional regeneration device, and as a result, the regeneration processing time can be shortened and the power consumption can be reduced. As a result, the temperature rise of the entire DPF is accelerated and the defective regeneration of the DPF can be reduced.

[Brief description of drawings]

FIG. 1 is a DP according to an embodiment of claims 1 and 2;
It is a whole schematic diagram of the reproducing | regenerating apparatus of F.

FIG. 2 is an embodiment of a pressure drop threshold map.

FIG. 3 is an explanatory diagram of variable control of heater energization.

FIG. 4 is an explanatory diagram of temperature changes on the upstream side and the downstream side of the DPF.

FIG. 5 is a flowchart of a DPF regeneration start determination.

FIG. 6 is a flowchart of a DPF regeneration process by variable control of heater energization.

FIG. 7 is an explanatory diagram of variable control of heater energization in one embodiment of claims 1 and 3;

FIG. 8 is a flowchart of a DPF regeneration process by variable control of heater energization.

FIG. 9 is a schematic view of a conventional DPF device.

FIG. 10 is an explanatory diagram of heater energization in a conventional DPF regeneration process.

FIG. 11 is an explanatory diagram of temperature changes on the upstream side and the downstream side of the DPF in the conventional DPF regeneration process.

[Explanation of symbols]

33 Exhaust manifold 35 engine 37 Exhaust pipe 39 Turbocharger 45,47 Branch pipe 49,51 DPF 59,61 Butterfly valve 63 controller 73,75 heater 95 Playback device 83,85,89 Pressure sensor 93 Rotation sensor 95 Playback device 97,99 temperature sensor

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F02D 45/00 F02D 45/00 314Z 378 378 F term (reference) 3G084 BA24 DA14 EA07 EA11 EB22 EC01 EC05 FA00 FA11 FA33 3G090 AA02 AA04 BA04 CA01 CA02 CB00 CB14 CB18 CB23 DA00 DA05 DA12 DA18

Claims (3)

[Claims] 1. A diesel particulate filter mounted on an exhaust system of a diesel engine, and an electric heater mounted upstream of the diesel particulate filter for burning and removing particulates collected by the diesel particulate filter, A parameter sensor that detects a predetermined parameter when the diesel engine is driven, a threshold value for starting regeneration of the diesel particulate filter based on the detection value of the parameter sensor, and first and second set times over a predetermined time after the start of regeneration. And a temperature sensor that is mounted on the upstream side of the diesel particulate filter to detect the temperature of the filter upstream side, and a time measuring means that measures the energization time to the electric heater. Based on the value detected by the parameter sensor With the start of regeneration of the diesel particulate filter,
The electric heater is energized to 100% for a first set time based on the time measured value of the time measuring means, and after the first set time has elapsed, the second time is set based on the time measured value of the time measuring means and the measured value of the temperature sensor. A regeneration device for a diesel particulate filter, wherein heater energization is variably controlled over a set time. 2. The regeneration device for a diesel particulate filter according to claim 1, wherein the control means performs pulse width modulation control on the heater energization for a second set time after the first set time has elapsed. . 3. The regeneration device for a diesel particulate filter according to claim 1, wherein the control means controls ON / OFF of energization of the heater for a second set time after the first set time has elapsed. .