JP2821831B2 - Exhaust gas purification device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas purifying apparatus for an internal combustion engine, and more particularly to a filter for trapping particulates, which prevents the filter from becoming abnormally high in temperature and prevents the filter from being damaged. The present invention relates to an exhaust gas purifying apparatus for an internal combustion engine.

[0002]

2. Description of the Related Art Exhaust gas from an internal combustion engine such as an automobile, particularly a diesel engine contains exhaust particulates mainly composed of carbon, which causes black smoke. From the viewpoint of environmental pollution, it is desirable to remove the particulates. In recent years, it has been proposed to dispose a ceramic filter in an exhaust passage of a diesel engine and remove the diesel particulates with the filter.

[0003] As described above, in an exhaust gas purifying apparatus for an internal combustion engine that removes particulates in exhaust gas by a filter, when the amount of particulates collected inside the filter increases with the use of the filter, the air permeability gradually increases. Lost,
Since the performance of the engine is reduced, it is necessary to periodically burn and regenerate the particulates collected in the filter.

Generally, in a conventional exhaust gas purifying apparatus for an internal combustion engine, when the air permeability of the particulate filter is lost and the pressure of the exhaust gas on the upstream side of the filter becomes larger than the pressure on the downstream side by a predetermined value or more ( The pressure sensor detects when the differential pressure has become equal to or greater than a predetermined value, and a particulate regeneration process is performed. In this regeneration process, an electric heater provided in the vicinity of the filter is usually energized, or a burner is ignited to ignite the collected particulates. To burn the particulates.

A conventional exhaust gas purifying apparatus for an internal combustion engine includes an air supply means for supplying secondary air for burning particulates collected by a filter, for example, as disclosed in Japanese Patent Application Laid-Open No. 2-256613. As disclosed in Japanese Unexamined Patent Publication (Kokai) No. H10-206, there is an apparatus that controls the flow rate of air for regeneration. In this method, after the heater is energized at the time of regeneration, the air flow rate is controlled based on the filter temperature, so that the regeneration conditions are changed and the regeneration of the filter is performed under optimum conditions.

[0006]

SUMMARY OF THE INVENTION However, Japanese Patent Laid-Open No.
In the exhaust gas purifying apparatus for an internal combustion engine disclosed in Japanese Patent No. 256813, the heater is always energized at the same time as the start of regeneration, so that the temperature immediately before the regeneration of the filter (hereinafter referred to as the filter preheating temperature).
When the temperature is high, when the regeneration is performed by using the heater, the filter temperature at the time of the regeneration is higher than the base preheating temperature, and in some cases, there is a possibility that the filter may be damaged such as a filter crack or a melt-down. Also, if the preheating temperature of the filter is 60
If the temperature is 0 ° C. or higher, there is a risk that even if the heater is not energized, the secondary air alone ignites, combustion occurs, and the filter is damaged.

More specifically, as shown in FIG. 7, the filter temperature at the time of regeneration largely depends on the amount of trapped particulates. According to experiments, in order to prevent the filter from causing regeneration failure and thermal damage, the temperature at the time of regeneration was 800
It is necessary to suppress the temperature to about 900 ° C., and the filter temperature before regeneration at this time is 600 ° C. or less. On the other hand, as a result of investigating the effects of the trapped amount of particulates and the preheating temperature of the filter on the combustion temperature during the regeneration of particulates, the conditions under which heat damage such as erosion, cracks, etc., or ignition failure occurred were found. Turned out to exist. This means, conversely, that in order to perform good combustion, there is an optimum filter preheating temperature having a certain width for a certain trapping amount.

However, in the apparatus disclosed in the above-mentioned publication, the sequence is based on the assumption that the amount of collected particulates is constant. In many cases, thermal damage may occur. In addition, the secondary air flow rate is controlled according to the preheating temperature of the filter. However, if the preheating temperature of the filter is high, the particulates are ignited just by flowing the secondary air, so that the temperature control is not performed. There was a fear that I could not do it. Further, in the device disclosed in the above-mentioned publication, the 2
Since the secondary air flow rate is constant, if the secondary air flow rate deviates from the optimum value on the way, the regeneration rate may decrease and unburned fuel may be generated.

Accordingly, the present invention solves the above-mentioned problems of the conventional exhaust gas purifying apparatus for an internal combustion engine, and controls the preheating temperature of the filter at the time of regeneration so as to optimize the combustion temperature of the filter. It is an object of the present invention to provide an exhaust gas purifying apparatus which controls the temperature at a low level, does not damage the filter during regeneration, and can obtain a high regeneration rate.

[0010]

According to the present invention, there is provided an exhaust gas purifying apparatus for an internal combustion engine which collects particulates in exhaust gas by a filter provided in an exhaust passage of the internal combustion engine and heats the particulates during regeneration. Means for heating the filter by the means and supplying regeneration gas from the regeneration gas supply means to burn the collected particulates to perform regeneration processing. means a regeneration timing determining means for determining regeneration timing of the filter, when the filter regeneration
And filter regeneration means for regenerating the filter is provided in accordance with the filter temperature immediately before the regeneration it was in when the year, the full
The filter regeneration means adjusts the filter temperature immediately before the regeneration to the
When the temperature is equal to or higher than the predetermined temperature, the time depends on the temperature
After the filter has been cooled naturally,
Detecting a temperature, the temperature being lower than the first predetermined temperature and the first
When the temperature is higher than the second predetermined temperature that is lower than the predetermined temperature
Actuates the regeneration gas supply means and activates the filter.
After the temperature is lowered, the regeneration process is performed, and the second predetermined process is performed.
A third location below the temperature and below the second predetermined temperature;
When the temperature is equal to or higher than a predetermined temperature, the regeneration process is immediately performed .

[0011]

According to the exhaust gas purifying apparatus for an internal combustion engine of the present invention, the temperature of the filter is detected by the temperature detecting means, and the regeneration timing of the filter is determined by the regeneration timing determining means. When the temperature immediately before is equal to or higher than a predetermined value, the regeneration gas supply means is operated by the filter regeneration means, and after the temperature of the filter is lowered, the heating means is activated to regenerate the filter. As a result, the preheating temperature of the filter before regeneration matches the optimal regeneration condition, and excessive combustion of the filter during regeneration is prevented, thereby preventing damage to the filter.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. However, the present invention can be applied to a regeneration operation of a dual filter type exhaust purification device and a single filter type exhaust purification device. is there. Therefore,
First, the configuration of a dual filter type exhaust gas purification device,
The operation at the time of collection and regeneration, and the configuration of the single filter type exhaust gas purification device, the operation at the time of collection and regeneration, will be briefly described, and then the present invention will be applied at the time of regeneration in both types of exhaust gas purification devices. The control at the time will be described.

FIG. 1 shows a schematic configuration of an embodiment of a diesel engine 1 equipped with an exhaust gas purifying apparatus 20 of a reverse flow alternating regeneration dual filter type to which the present invention is applied. An exhaust pipe 2 that guides exhaust gas from the engine 1 is branched into branch pipes 2A and 2B at a branch part a, and then joined at a junction b and connected to the muffler 6.
Casing 3A provided in the middle of branch pipe 2A, 2B,
3B includes a first filter 5A and a second filter 5A for collecting particulates in the exhaust gas.
B is provided. As the first filter 5A and the second filter 5B, a honeycomb filter having many filter cells is used, and the exhaust upstream end and the downstream end of each filter cell are alternately plugged with plugs. Therefore, the particulates in the exhaust gas flowing into the first and second filters 5A and 5B are collected in the filter cells when the exhaust gas passes through the wall surfaces of the filter cells.

A temperature sensor ST and a pressure sensor SPU are provided on the upstream side of the branch portion a of the branch pipes 2A and 2B, and a pressure sensor SPD is provided on the downstream side of the junction b. Then, the pressure difference (differential pressure) between the upstream and downstream of the first and second filters 5A, 5B is obtained by inputting the outputs of the pressure sensors SPU and SPD to an ECU (control circuit) 100. The control circuit 100 determines the regeneration timing of the first and second filters 5A and 5B based on the differential pressure.

On the other hand, the plugs (not shown) near the downstream end surfaces of the first and second filters 5A and 5B or the plug members (not shown) at the downstream end heat the filters to ignite the particulates during filter regeneration. Electric heaters HA and HB are provided. One end of each of the electric heaters HA and HB is grounded, and the other end is a switch SW controlled by the control circuit 100.
A, and connected to the battery 11 via SWB.

At the time of regeneration of the first and second filters 5A and 5B, the electric heater HA or HB is energized, and the first or second filter 5 on the energized side is also energized.
It is necessary to flow the regeneration gas from the downstream side of A and 5B and discharge the combustion gas from the upstream side. Therefore, in this embodiment, the regeneration gas supply port 17 is provided at the junction b of the branch pipes 2A and 2B, and the regeneration gas supply port 17 is provided with a switching valve V3 on the way. Secondary air is supplied as a regeneration gas from the electric air pump 9 through the gas supply passage 7. The drive of both the electric air pump 9 and the on-off valve V3 is controlled by the control circuit 100. A regeneration gas discharge port 18 is provided at a branch portion a of each of the branch pipes 2A and 2B. One end of the regeneration gas discharge port 18 is opened to the atmosphere, and an on-off valve V4 is provided on the way.
Is connected to the regeneration gas discharge passage 8.
The on-off valve V4 is also driven and controlled by the control circuit 100.

The branch pipe a where the regeneration gas discharge port 18 opens has an exhaust pipe 2 and a branch pipe 2 upstream of the branch pipe a.
A, 2B and a first control valve V1 for switching the connection between the regeneration gas discharge port 18 and the regeneration gas supply port 17 are provided.
Is provided with a second control valve V2 for switching the connection of the exhaust pipe 2, the branch pipes 2A and 2B, and the regeneration gas supply port 17 on the downstream side of the junction b.

The first and second control valves V1 and V2 are both driven by a control circuit (ECU) 100. The first and second control valves V1 and V2 are controlled by a control signal from the control circuit 100. Are linked to each other, and are positioned at the solid line position C, the broken line position B, and the dashed line position A. Valve V1
The driving of the V4 is actually performed by a diaphragm type actuator, a negative pressure switching valve, or an electric type actuator, but the driving mechanism is not particularly limited, so that illustration and description thereof are omitted here. .

The dashed-dotted position a of the first and second control valves V1 and V2 is the position where the second filter 5B is trapped, and the exhaust gas from the engine 1 flows through the second filter 5B and passes through the muffler 6. Is released into the atmosphere. At this time, the on-off valves V3 and V4 are closed when the first filter 5A is not regenerating, but the on-off valves V3 and V4 are closed when the first filter 5A is regenerating.
3, V4 is opened and the heater HA is energized.
The regeneration gas from the air pump 9 flows from the supply port 17 through the first filter 5A to assist the burning of the particulates, and the combustion gas is discharged from the discharge port 18 into the atmosphere.

The broken lines B of the first and second control valves V1 and V2 indicate the positions where the first filter 5A is trapped. Exhaust gas from the engine 1 flows through the first filter 5A and passes through the muffler 6. Released into the atmosphere. At this time, the on-off valves V3 and V4 are closed when the second filter 5B is not regenerating, but the on-off valves V3 and V4 are closed when the second filter 5B is regenerating.
In 4, the valve is opened and the heater HB is energized, and the regeneration gas from the air pump 9 flows through the supply port 17 through the second filter 5 </ b> B to assist the burning of particulates, and the combustion gas is discharged from the discharge port 18 into the atmosphere. Is discharged.

The present invention provides first and second filters 5A and 5B.
When the first filter 5A or the second filter 5B is in the regeneration state based on the detected value of the differential pressure between the upstream and downstream sides, the regeneration is properly controlled. FIG. 2 shows a schematic configuration of a diesel engine 1 provided with a single filter type exhaust gas purification apparatus 30 to which the present invention is applied, and the same components as those in FIG. is there. In FIG. 2, 3 is a casing for accommodating a particulate filter 5 provided in a part of the exhaust pipe 2, 4 is a sealing material, 7 is a secondary air supply passage, 8 is a combustion gas discharge passage, and 9 is 2 Air pump for supplying the next air, 1
0 is an exhaust gas bypass passage that bypasses the particulate filter 5, 11 is a battery, 100 is a control circuit, SW
Is a heater switch for energizing the electric heater H, SP
U is a pressure sensor provided in the passage 2 on the exhaust gas inflow side of the particulate filter 5, SPD is a pressure sensor provided in the passage 2 on the exhaust gas outflow side of the particulate filter 5, and ST is a particulate filter 5 V5 is a switching valve for switching between the exhaust passage 2 and the exhaust bypass passage 8, V6 is an outlet switching valve provided at the outlet of the exhaust bypass passage 8, and V3 is a secondary air supply passage 7. V4 is an on-off valve for the combustion gas discharge passage 8.

The control circuit 100 includes, for example, an interface INa for inputting an analog signal, an interface INd for inputting a digital signal, a converter A / D for converting an analog signal into a digital signal, a central processing unit CPU for performing various arithmetic processing, a random processing unit CPU, The microcomputer includes a microcomputer including an access memory RAM, a read-only memory ROM, an output circuit OUT, and a bus line 111 for connecting them, but a detailed description of the configuration is omitted. An analog signal input interface INa of the control circuit 100 includes pressure detection signals from pressure sensors SPU and SPD for detecting the pressure of exhaust gas on the upstream and downstream sides of the exhaust gas path of the particulate filter 5, and a temperature sensor ST. , A filter inlet temperature detection signal from an engine speed sensor N (not shown)
e, etc., and a signal from a key switch (not shown) is input to the digital signal input interface INd.

At the time of collecting particulates in the normal exhaust gas, the valves V3 to V6 are controlled to the positions indicated by broken lines, and the exhaust gas discharged from the diesel engine 1 is supplied to the particulate filter contained in the casing 3. The particulates are removed by 5 and released into the atmosphere via a muffler (not shown). When the pressure difference before and after the particulate filter 5 exceeds a regeneration timing determination value described later, the control circuit 100 controls the valves V3 to V6.
Is switched from the position indicated by the broken line to the position indicated by the solid line, and the regeneration operation of the particulate filter 5 is performed. The control circuit 1 determines when to switch from the particulate collection operation to the regeneration operation of the filter 5 or to control the heater switch SW on / off and control the flow rate of the secondary air from the air pump 9 at the time of filter regeneration.
00 is performed.

In the embodiment shown in FIG. 2, a temperature sensor ST is provided on the inlet side of the filter 5 in order to detect the temperature of the particulate filter 5, but this temperature sensor ST is embedded in the filter 5. But it's good. Here, the regeneration process performed by the control circuit 100 at the time of regeneration of the particulate filter will be described with reference to the flowchart of FIG. The routine shown in FIG. 3 is executed every predetermined time, for example, every 50 ms.

In step 301, the pressure difference Δ across the filter
It is determined whether or not P is larger than the lower limit value ΔPL of the regeneration reference value. When ΔP ≦ ΔPL, the collection amount of the particulates in the filter has not reached the regeneration timing, and this routine ends. On the other hand, in step 301, ΔP> ΔP
In the case of L, it is determined that the filter has entered the regeneration area, and the routine proceeds to step 302, where the filter temperature T of concentration is read in step 302.

Steps 303 and 304 determine whether or not the read filter temperature is a temperature suitable for regeneration.
It is determined whether the temperature is higher than the temperature T.
Is higher than 150 ° C. First, control when the filter temperature T is between 150 ° C. and 200 ° C., which is the optimum temperature for regeneration, will be described. In this case, step 3
03 is NO, and step 304 is also NO, and the process proceeds to step 305. In step 305, the flow path of the filter to be regenerated is closed. In the dual type exhaust gas purifying apparatus described with reference to FIG. 1, the trapping filter is closed by switching the control valves V1 and V2, and the exhaust gas flows to the other filter. In the exhaust gas purifying apparatus, the switching valve V
5 and V6 are switched to close the collection filter and exhaust gas flows through the exhaust bypass passage 10. In step 306, the heater is energized to ignite the particulates in the filter, and the air pump 9 supplies an optimal amount of secondary air for combustion to perform a filter regeneration process. This reproduction process is well known, and will not be described in detail here.

Next, control when the temperature T of the filter is lower than the optimum temperature 150 ° C. to 200 ° C. for regeneration will be described. This time is NO in step 303, the process proceeds to step 307 becomes YES in step 304. In step 307, it is determined whether or not the differential pressure ΔP before and after the filter is larger than the lower limit ΔPH of the regeneration reference value, and ΔP ≦ ΔP
If H, do nothing and end this routine. This is because, since the filter temperature is low, there is a possibility that unburned particulates may occur even if the regeneration process is performed, and thereafter, the temperature T may rise to the optimal regeneration temperature of the filter. On the other hand, when it is determined in step 307 that ΔP> ΔPH, the process proceeds to step 305 to close the flow path of the filter that has been in the trapping state so far,
The regeneration process is performed in the same manner as when the temperature of the filter is in the optimum state. This is because the amount of trapped particulates is large, so that even if regeneration is performed with the filter temperature T being low, the combustion temperature rises and the generation of unburned residue is small.

Finally, control when the temperature T of the filter is higher than the optimum temperature 150 ° C. to 200 ° C. for regeneration will be described. At this time, the determination in step 303 becomes YES, and the process proceeds to step 308 and subsequent steps. In step 308, step 3
The flow path of the filter to be regenerated is closed in the same manner as described in 05. Then, in step 309, it is determined whether or not the filter temperature T is lower than 600 ° C. When T <600 ° C., the process proceeds to step 310 to supply and cool the secondary air to the filter, and when T ≧ 600 ° C. Proceed to step 312 to cool the filter naturally.

In step 310, referring to a map showing the relationship between the filter temperature T and the secondary air supply amount as shown in FIG. The driving time t of the air pump 9 is calculated from the amount. The drive time t is such that the filter temperature is 150 ° C.
From 200 to 200 ° C. And
In step 311, the air pump 9 is driven for the drive time t to cool the filter with the secondary air. After the filter temperature T is set to 150 ° C. to 200 ° C., the process proceeds to step 306, where the filter is regenerated.

On the other hand, in step 312, a natural cooling time tn corresponding to the temperature T is calculated by interpolation with reference to a map showing the relationship between the filter temperature T and the natural cooling time as shown in FIG.
Is calculated. Then, in step 313, the filter is naturally cooled for the cooling time tn.
In, the filter temperature T is detected, and the process returns to step 309. Then, if the filter temperature T naturally cooled for the cooling time t becomes less than 600 ° C. in step 309, the process proceeds to step 310 and thereafter, the cooling is performed by the air pump 9, and then the regeneration is performed.

As described above, in the above-described embodiment, when the differential pressure across the filter exceeds a predetermined value, regeneration is performed as long as the filter temperature is within a temperature range suitable for regeneration. If the air can be supplied, secondary air is supplied and the filter temperature is reduced to a temperature range suitable for regeneration, and then regeneration is performed. If the filter temperature is in a high temperature range where secondary air cannot be supplied, natural Cooling is performed, and the filter temperature is once reduced to a temperature at which secondary air can be supplied. Thereafter, secondary air is supplied to lower the filter temperature to a temperature range suitable for regeneration, and then regeneration is performed. Therefore, the preheating temperature of the filter at the time of regeneration is optimized, and the combustion temperature does not rise excessively, so that the filter is not damaged during regeneration and a high regeneration rate can be obtained.

In the above-described embodiment, the amount of trapped particulates in the filter is not considered when controlling the preheating temperature of the filter. However, as shown in FIG.
The optimum combustion temperature range at the time of regeneration of the filter changes depending on the amount of trapped particulates in the filter. Therefore, when performing finer control, the determination values 150 ° C. and 200 ° C. of the filter temperature T shown in FIG. 3 may be changed according to the amount of trapped particulates in the filter.

FIG. 8 shows an embodiment in which the preheating temperature of the filter at the time of regeneration is changed in accordance with the trapped amount of particulates in the filter. In step 801, the filter pressure difference ΔP and the filter temperature Tf are detected, and in step 802, it is determined whether or not the filter pressure difference ΔP is equal to or higher than the regeneration lower limit value P _SET . If ΔP <P _SET , this routine is terminated and ΔP
In the case of ≧ P _SET , in step 803 and thereafter, the magnitudes of the predetermined values P ₁ and P ₂ (P _SET <P ₁ <P ₂ ) are compared. Then, when ΔP is larger than the predetermined value P _2, the process proceeds to step 807 (the α positive predetermined temperature value) 2.alpha preheating temperature determination value T _SET filters reduced only to later proceed from step 803 to step 80 4. Also, P ₁ <ΔP <
Proceeds to step 806 becomes YES at NO and the step 805 at step 803 when the P _2, the process proceeds to step 807 to reduce the preheat temperature determination value T _SET filter only alpha. Further, when P _SET <ΔP <P ₁ , step 803,
Since the NO both at 805, the process proceeds to step 807 without changing the preheating temperature determination value T _SET filter.

In step 807, the flow path of the filter to be regenerated is closed, and in step 808, the filter temperature T
It is determined whether or not f is equal to or greater than the preheating temperature determination value _TSET . T
If f ≧ T _SET , the routine proceeds to step 809, where the air pump is driven to cool the filter. The cooling of the filter by this air pump is performed in step 808 with Tf <T
_It continues until it becomes _SET . Then, as the amount of trapped particulates in the filter increases, the preheating temperature determination value T
_Since the value of _SET is small, the preheating temperature of the filter is low.

[0035] When the filter temperature Tf is lowered than the preheating temperature determination value T _SET at the step 808, normal reproduction processing proceeds to subsequent step 810 is performed. That is, step 8
At 10, power is supplied to the electric heater to ignite the particulates, and at step 811 the air flow rate from the air pump is controlled to the optimal value Q _best for combustion. Step 812 is intended to determine whether the heater energization time T _heat has elapsed, the energization of the heater in step 813 when the heater energization time T _heat has elapsed is stopped,
In step 814, it is determined whether the regeneration of the filter has been completed. When the regeneration of the filter is completed, the process proceeds to step 815, where the driving of the air pump is stopped,
In step 816, the flow path of the filter being regenerated is switched, and the filter is again in the trapping state.

[0036]

As described above, according to the present invention, by controlling the preheating temperature of the filter at the regeneration time to be optimum, the combustion temperature of the filter is controlled to the optimum temperature, There is an effect that the filter is not damaged and a high reproduction rate can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration example of an exhaust gas purification device of a reverse flow alternating regeneration dual filter type to which the present invention is applied.

FIG. 2 is a diagram showing a schematic configuration example of a single type exhaust gas purification apparatus to which the present invention is applied.

FIG. 3 is a flowchart showing a procedure of a reproduction process according to the present invention.

FIG. 4 is a diagram showing a relationship between a filter temperature before the start of regeneration and a supply amount of secondary air for setting the filter temperature to an optimum preheating temperature.

FIG. 5 is a diagram showing a relationship between a filter temperature before the start of regeneration and a natural cooling time for setting the filter temperature to a temperature at which secondary air can be supplied.

FIG. 6 is a diagram showing a relationship between a trapped amount of particulates in a filter and an optimum combustion temperature range of the filter.

FIG. 7 is a diagram illustrating a relationship between a trapped amount of particulates in a filter and a combustion temperature during regeneration of the filter.

FIG. 8 is a flowchart showing another example of the procedure of the reproduction process of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Diesel engine 2 ... Exhaust pipe 2A, 2B ... Branch pipe 5A, 5B ... Filter 7 ... Regeneration gas supply passage 8 ... Regeneration gas discharge passage 9 ... Air pump 10 ... Bypass passage 17 ... Regeneration gas supply port 18 ... Regeneration Gas exhaust port 30 ... Exhaust brake device 100 ... Control circuit a ... Branch b ... Confluence H, HA, HB ... Electric heater SPU, SPD ... Pressure sensor V1 ... First control valve V2 ... Second control valve V3 , V4 ... On-off valve V5, V6 ... Switching valve

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-149126 (JP, A) JP-A-2-256813 (JP, A) JP-A-2-215913 (JP, A) (58) Field (Int.Cl. ⁶ , DB name) F01N 3/02 341

Claims (1)

(57) [Claims] 1. A filter provided in an exhaust passage of an internal combustion engine to collect particulates in exhaust gas, to heat the filter by a heating means at a regeneration time, and to supply and capture a regeneration gas from a regeneration gas supply means. In an exhaust gas purification apparatus for an internal combustion engine that performs a regeneration process by burning collected particulates, a temperature detection unit that detects a temperature of the filter, a regeneration timing determination unit that determines a regeneration timing of the filter, and the filter includes: Phil immediately before the regeneration when in playback time
And filter regeneration means for regenerating the filter is provided in accordance with the data the temperature, the filter regeneration means, wherein immediately before the regeneration of the filter temperature
However, when the temperature is equal to or higher than the first predetermined temperature, the time is according to the temperature.
After the filter has been cooled naturally,
Detecting a temperature that is lower than the first predetermined temperature and higher than the first predetermined temperature;
Lower than the second predetermined temperature, the regeneration gas
After activating the supply means and lowering the temperature of the filter
Performing the regenerating process, at a temperature equal to or lower than the second predetermined temperature and higher than the second predetermined temperature;
Immediately above the third predetermined temperature, which is lower than the third predetermined temperature.
Exhaust purifying apparatus for an internal combustion engine and performing management.