JPH07253012A - Exhaust fine particle processing device of internal combustion engine - Google Patents

Abstract

PURPOSE:To attempt optimization of regeneration throughout the regenerating period of a filter, so as to enable the filter to be regenerated at high efficiency by decreasing and correcting the oxygen amount required for regeneration (combustion) according to the degree of progress of regenerative processing of the filter. CONSTITUTION:A regenerative exhaust gas flow control valve 108 is provided in parallel with a first passage selector valve 106 provided downstream from a filter case 104 provided in an exhaust system of an engine 100, and a second passage selector valve 109 is provided inside a branch passage 103 detouring around a filter case 104. When a filter is regenerated, regeneration is started in a state where the first passage selector valve 106 is closed and the regenerative exhaust gas flow control valve 108 and the second passage selector valve 109 are opened, and the regenerative exhaust gas flow control valve 108 is closed after the specific time passes. That is, the amount of exhaust gas to flow into a filter 105 is increased in the early regenerating stage, and then the exhaust gas inflow amount is decreased. Thereby the amount by which the calorific value of the exhaust gas 3 carried away is decreased, and combustion by heating is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust particle processing apparatus for collecting fine particles contained in exhaust gas of an internal combustion engine and treating the collected fine particles.

[0002]

2. Description of the Related Art Conventionally, from the viewpoint of environmental protection, fine particles (particulate "PM;
In order to prevent (rticulate Mattar ") from being discharged into the atmosphere, an exhaust particulate treatment device has been proposed in which the particulates are collected by a filter provided in the exhaust system. But,
When the collected exhaust particulates are deposited on the filter and the filter is clogged, the filter becomes a large passage resistance and the exhaust pressure increases, which results in deterioration of engine performance and deterioration of fuel consumption. Therefore, it is necessary to remove the trapped exhaust particulates from the filter to regenerate the filter.As a method for regenerating the filter, the trapped exhaust particulates are ignited through an electric heater or the like to propagate combustion. It is considered to be burned down by.

A conventional exhaust particulate treatment apparatus using such a regeneration method detects, for example, the operating state of the engine, estimates the amount of exhaust particulate discharged from the engine based on the detected operating state of the engine, and defines it in the filter. When the exhaust particulates in the exhaust gas are accumulated, the valve provided in the exhaust passage is closed to control the amount of oxygen required for regeneration while adjusting the exhaust (regeneration exhaust) flow rate while suppressing the amount of heat taken away by the exhaust, thus improving efficiency. Some people often try to regenerate the filter (Japanese Patent Application No. 5-5).
No. 4032).

[0004]

In such a conventional apparatus, as shown in FIG. 6, when the regeneration of the filter is started, the particulates deposited on the filter are heated by the electric heater and first, " Combustion "progresses.
This "combustion by propagation" requires a sufficient amount of oxygen and is completed in a relatively short time (the period [0 to t in FIG.
1] corresponds to the combustion period due to propagation).

However, it is difficult to carry out regeneration sufficiently only by "combustion by propagation" and some unburned residue remains. Therefore, it is necessary to continue the heating by the electric heater to burn the particulates even after the “combustion by propagation” is completed. Combustion during heating by the electric heater is defined as "combustion due to heating" in order to distinguish it from "combustion due to propagation" (period [t1 to t in FIG.
2] corresponds to the combustion period due to heating).

Even in the case of "combustion by heating", exhaust gas for regeneration is required, but the progress of "combustion by heating" is
Since it is slower than "propagation combustion", the required regeneration exhaust flow rate per unit time (that is, regeneration oxygen supply amount)
Should be less than in "combustion by propagation". However, in the conventional device, the flow rate of the exhaust gas for regeneration is adjusted according to the amount required for "combustion by propagation". Therefore, at the time of "combustion by heating", surplus regeneration exhaust gas is supplied. As a result, the amount of heat is taken away, "combustion by heating" cannot be performed well, and there is a problem that the unburned particulates after "combustion by propagation" cannot be effectively combusted.

The present invention has been made in view of such conventional problems, and makes it possible to favorably perform combustion by propagation and combustion by heating, thereby improving the regeneration efficiency of the filter. An object of the present invention is to provide an exhaust particulate treatment device for an internal combustion engine that is further enhanced.

[0008]

Therefore, as shown in FIG. 1, an exhaust particulate treatment system for an internal combustion engine according to a first aspect of the present invention is installed in an exhaust passage of the internal combustion engine, and the exhaust particulate matter A filter A for collecting fine particles, a regeneration time detecting means B for detecting the regeneration time of the filter A, and the filter A
Filter temperature raising means C for raising the temperature of the exhaust gas, and exhaust gas inflow amount control means D for controlling the amount of exhaust gas flowing into the filter A to be reduced.
When the regeneration timing is detected by the regeneration timing detecting means B, the oxygen inflow control means D controls the exhaust flow rate flowing into the filter A so that the filter temperature raising means C controls the filter A. In an exhaust particulate treatment system for an internal combustion engine in which the temperature of the filter A is raised to regenerate the filter A, the amount of oxygen per unit time flowing into the filter A depending on the progress of the regeneration process during regeneration of the filter A The oxygen inflow control means E for reducing the amount is provided.

According to the second aspect of the present invention, the amount of oxygen per unit time flowing into the filter A during the regeneration of the oxygen inflow amount control means E within a predetermined time from the start of operation of the filter temperature raising means C. In comparison with the above, the amount of oxygen per unit time flowing into the filter A during the period from the lapse of the predetermined time to the end of regeneration is reduced by a predetermined amount,
The amount of oxygen flowing into the filter A is reduced and corrected.

According to the third aspect of the present invention, the predetermined time is configured to be a time when combustion by propagation is substantially completed. In the invention according to claim 4, the oxygen inflow control means E is configured to correct the amount of oxygen flowing into the filter A at the time of regeneration so as to decrease the amount of oxygen flowing into the filter A so as to increase the combustion speed of the particulates collected in the filter A. Configured.

According to the fifth aspect of the invention, the oxygen inflow amount control means E is constituted by means for controlling the exhaust gas flow rate flowing into the filter A. In the invention according to claim 6, the oxygen inflow control means E is configured to include a secondary air supply means for supplying the secondary air to the filter A.

[0012]

According to the exhaust gas treating apparatus for the internal combustion engine having the above-mentioned structure, when the regeneration timing is detected by the regeneration timing detecting means, the exhaust gas inflow amount controlling means causes the exhaust gas to flow into the filter. Control the amount of exhaust
The filter temperature raising means is operated to regenerate the filter in a state in which the amount of heat removed by the exhaust gas passing through the filter is suppressed. Combustion) is active, but as the regeneration process progresses, the amount of fine particles deposited on the filter decreases and regeneration (combustion) becomes inactive, and the oxygen required for regeneration (combustion) depends on the progress of the regeneration process. The amount will decrease. For this reason, the amount of oxygen supplied according to the degree of progress of the regeneration process is reduced and corrected through the oxygen inflow amount control means. As a result, the amount of oxygen required for regeneration (combustion) is controlled throughout the regeneration period of the filter, so that the regeneration of the filter can be optimized and the regeneration of the filter can be performed with high efficiency.

According to a second aspect of the present invention, the correction for reducing the amount of oxygen inflow control means is compared with the amount of oxygen per unit time flowing into the filter within a predetermined time from the start of operation of the filter temperature raising means. The amount of oxygen per unit time flowing into the filter after the lapse of a predetermined time until the end of regeneration is reduced by a predetermined amount. Thus, during a period in which combustion of the collected fine particles is active within a predetermined time from the start of operation of the filter temperature raising means, the amount is controlled to decrease so as to supply a relatively large amount of oxygen commensurate with the combustion. The combustion can be optimized and
When the combustion is not relatively active after the lapse of the predetermined time until the end of regeneration, the combustion can be optimized during the period by controlling the amount of oxygen to a relatively small amount of oxygen commensurate with the period. Therefore, the filter can be regenerated with high efficiency with a relatively simple structure.

According to the third aspect of the present invention, the predetermined time is set to be a time at which combustion due to propagation is substantially completed. Therefore, in the combustion of fine particles within a predetermined time from the start of operation of the filter temperature raising means. By setting the end of the dominant "combustion by propagation", it is possible to optimize "combustion by propagation" and then optimize "combustion by heating" and eliminate waste during regeneration. Therefore, the regeneration of the filter is performed with higher efficiency.

According to the fourth aspect of the invention, the filter regeneration processing time is shortened by reducing the amount of combustion so that the combustion speed of the particulates collected by the filter is increased. For example, the present invention is applied to the invention of claim 3, and within the predetermined time from the start of the operation of the filter temperature raising means, the weight reduction control is performed so as to increase the combustion speed of “combustion by propagation” of the particulates collected in the filter, From the time after the lapse of the predetermined time until the end of regeneration, if the weight reduction control is performed so as to increase the combustion speed of "combustion by heating", each combustion time can be shortened. The reproduction processing time will be shortened.

According to the fifth aspect of the invention, since the oxygen inflow control means is a means for controlling the exhaust flow rate flowing into the filter, it is not necessary to provide a separate oxygen supply device, etc. The increase can be suppressed. In the invention according to claim 6, the oxygen inflow control means is
Since the secondary air supply means for supplying the secondary air to the filter is included, the accuracy of controlling the supply oxygen amount is improved and it is not affected by the change in the operating state of the engine, so that it is stable and optimal. It is possible to perform regeneration processing of various filters.

[0017]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 2 shows the configuration of the exhaust particulate treatment system according to the first embodiment of the present invention. Exhaust passage 101 connected to exhaust manifold of internal combustion engine 100
In the middle of the first branch passage 102 and the second branch passage
It is configured such that it is once branched into the branch passage 103 and then merges again.

In the first branch passage 102, a filter 105, which is installed in a filter case 104 and collects particulates in the exhaust gas, is interposed. A first flow path switching valve 106 that controls the amount of exhaust gas flowing into the filter 105 is provided downstream of the filter case 104 in the first branch passage 102 on the exhaust gas downstream side. Furthermore, the first
A bypass passage 107 that bypasses the flow path switching valve 106 is provided, and a regeneration exhaust flow rate adjusting valve 108 is interposed in the bypass passage 107.

A second flow path switching valve 109 for controlling the amount of exhaust gas flowing into the filter 105 is provided in the middle of the second branch passage 103. Here, the regeneration exhaust flow rate adjusting valve 108 is for adjusting the exhaust flow rate flowing into the filter 105 during regeneration of the filter 105. Further, the second branch passage 103 is
It is a passage for bypassing the filter 105 and exhausting it while the filter 105 is being regenerated.

A first valve drive device 110 for opening and closing the first flow path switching valve 106 and the regeneration exhaust flow rate adjusting valve 108, and a second valve drive for opening and closing the second flow path switching valve 109. A device 111 is provided. The first valve drive device 110 and the second valve drive device 111 are controlled based on a drive signal from the control unit 117. The first flow path switching valve 106 and the regeneration exhaust flow rate adjusting valve 108 may be opened and closed by separate valve drive devices.

Here, the first flow path switching valve 10
6. The control unit 117 constitutes the exhaust gas inflow amount control means according to the present invention. Also, the first branch passage 1
02, the first flow path switching valve 106, the second branch passage 1
03, the second flow path switching valve 109, the bypass passage 107, the regeneration exhaust flow rate adjusting valve 108, the control unit 117, and the like constitute the oxygen inflow control means according to the present invention.

An electric heater 112 for heating and burning the particulates collected by the filter 105 is provided on the exhaust gas upstream side of the filter 105.
A heater drive circuit 113 for driving the electric heater 112 is provided. The heater drive circuit 113 is controlled based on a drive signal from the control unit 117.

Here, the electric heater 112 is
The filter temperature raising means according to the present invention is configured. Further, the load of the engine (basic injection amount Tp, accelerator opening C / L,
Engine operating state detecting means 11 for detecting the operating state of the engine such as throttle opening TVO), engine speed, cooling water temperature, etc.
4 are provided. The operating state detecting means 114 can utilize a throttle sensor, a crank angle sensor, a water temperature sensor, etc. which are usually used for engine control.

Then, an emission amount detecting means 115 for detecting / estimating the amount of particulate emissions from the engine 100 and the amount of particulate deposits on the filter are estimated, and the amount of deposits is detected to judge the regeneration timing and regeneration termination timing. Means 116
Is provided. The discharge amount detecting means 115 and the deposit amount detecting means 116 are provided in the CPU, ROM, R, as will be described later.
A control unit 117 including a microcomputer including an AM, A / D converter, an input / output interface and the like is provided as software.

The operation of the filter regeneration of this embodiment having the above construction will be described below. When collecting particulates with the filter 105, the first flow path switching valve 106 is opened via the first valve drive device 110, and the second flow path switching valve 109 is opened via the second valve drive device 111. And close the valve, filter 1
05 to let the exhaust gas pass through.

When the filter 105 reaches the regeneration time, first, the first flow path switching valve 106 on the downstream side of the filter 105 is closed via the first valve drive device 110, and the regeneration exhaust flow rate is set. The adjustment valve 108 is opened, and
The second flow path switching valve 109 is opened via the second valve drive device 111. As a result, the passage resistance on the side of the first branch passage 102 increases, so that only the exhaust gas limited to the predetermined amount v1 flows into the filter 105, which optimizes "combustion by propagation" as described later. In addition, the increase in exhaust resistance is suppressed, and the deterioration of drivability during filter regeneration is prevented.

In this state, the electric heater 112 is energized and heated via the heater drive circuit 113 to start regeneration of the filter. After energization of the electric heater 112, while "combustion by propagation" is in progress (that is, as shown in FIG. 6, time t1 from start of regeneration 0 to end of combustion propagation).
Until. Note that, as shown in FIGS. 8 and 9, such t1
Changes according to the driving range during regeneration. ), The regeneration exhaust flow rate adjusting valve 108 is opened, so that the amount of regeneration exhaust necessary for “combustion by propagation” is increased by the filter 10.
5, the "combustion by propagation" is optimized, and the filter 105 is regenerated well.

After the "combustion by propagation" is completed,
Until the regeneration is completed (that is, from t1 to time t2 when the regeneration is completed), the exhaust gas flow rate adjusting valve 108 for regeneration is used.
Close. As a result, the passage resistance on the side of the first branch passage 102 increases as compared with the time of "combustion by propagation", so as shown in FIGS. 5 and 7, the amount is limited to the amount (v2) required for "combustion by heating". Exhaust for regeneration (as described above,
This is less than the exhaust flow rate required for "combustion by propagation". ) Will flow into the filter 105. That is, the first flow path switching valve 106 and the regeneration exhaust flow rate adjusting valve 1
The exhaust gas leaking from 08 supplies oxygen necessary for "combustion by heating". Regarding the detection of the regeneration timing, the discharge amount detection means 115 uses the discharge amount detection means 115 based on the detection signal of the operation state detection means 114 for detecting the accelerator opening degree, the engine rotation speed, etc. Refer to the search map in to detect particulate emissions from the institution.

Further, the accumulation amount detecting means 116 detects the accumulation amount of particulates on the filter 105 based on the detection results of the operating state detecting means 114 and the discharge amount detecting means 115. Then, the deposition amount detecting means 116 determines the regeneration timing and the regeneration termination timing of the filter 105 when the deposition amount exceeds a predetermined amount, and starts regeneration based on the determination result. Therefore, the accumulation amount detecting means 116 constitutes the regeneration timing detecting means according to the present invention.

Next, a description will be given according to the flow charts shown in FIGS. In step (denoted by S in the figure, the same applies hereinafter) 1, signals such as the engine speed and the engine load are read. The step 1 constitutes the operating state detecting means 114. In step 2, the total amount of particulate emissions from the engine 100 per unit time is calculated as shown in FIG.
It is obtained by searching with reference to the 0 operating area & particulate emission search map. The step 2 constitutes the discharge amount detecting means 115.

In step 3, it is determined whether the filter 105 is being regenerated. Step 15 if playing
Go to step 4, and if not reproducing, go to step 4. In step 4, the particulate accumulation amount β on the filter 105 is obtained from the total particulate emission amount (integrated amount) obtained in step 2. In step 5, the filter 10
It is determined whether or not the particulate accumulation amount β to 5 exceeds the reproducible accumulation amount βRe which is the regeneration time. If it is determined that the particulate accumulation amount β exceeds the reproducible accumulation amount βRe and the regeneration time has come, the process proceeds to step 6, and if it is determined that it is not the regeneration time, the process proceeds to step 1.

At step 6, a reproduction flag is added to indicate that the filter 105 is being reproduced. In step 7, the first flow path switching valve 106 on the filter 105 side is set to the first
The valve is closed via the valve drive device 110. In step 8,
The second flow path switching valve 109 on the second exhaust passage 103 side is
The valve is opened via the valve drive device 111.

Then, the process proceeds to the flow chart A shown in FIG. In Flowchart A, step 1 described below
3 to step 19 are executed. In step 13,
The regeneration exhaust flow rate adjusting valve 108 for controlling the regeneration exhaust amount for “combustion by propagation” is provided in the first valve drive device 1.
Open through 10. In step 14, supply of a predetermined amount of regeneration power to the electric heater 112 is started via the heater driving circuit 113.

In step 15, the time t1 at which "combustion by propagation" ends in the operating state at the time of regeneration is searched from the map showing the relationship between the operating state shown in FIG. 8 and the end time of "combustion by propagation". As shown in FIGS. 8 and 9, in the operating region 1, t1 = t11, and the operating region 2
In this case, t1 = t12. In addition, operating area 1
Indicates that the oxygen concentration in the exhaust gas is higher than that in the operating range 2
Therefore, the combustion is completed faster in the operating region 1 because of the higher value than that of t11. Therefore, there is a relationship of t11 <t12.

In step 16, it is determined whether the energization time t of the electric heater 112 has reached the end time t1 of "combustion by propagation". In the case of reproduction in the operation area 1 shown in FIG. 8, based on the search result in step 15, t1
Is set to t11, and if the reproduction is in the operating region 2, t
1 is set to t12. In step 17, as shown in FIG. 6, since the energization time t of the electric heater 112 has passed t1 (t11 in the operation region 1), it is judged that the combustion of the particulates due to the propagation is completed, and the regeneration is performed. The exhaust gas flow rate adjusting valve 108 is closed. As a result, the regeneration exhaust flow rate is reduced from V1 to V2 as shown in FIG. 7, and is adjusted to the optimal regeneration exhaust flow rate V2 for “combustion by heating” as shown in FIG. By adjusting the regeneration exhaust flow rate, as shown in FIG. 5, during "combustion by propagation",
It is possible to optimize the respective particulate burning rates during "burning by heating".

In step 18, it is judged whether the energization time t of the electric heater 112 has exceeded a predetermined time t2. At step 19, since the predetermined time t2 has passed,
The electric heating of the electric heater 112 is stopped. When steps 13 to 19 (flow chart A) are completed as described above, the process then returns to step 9 of the flow chart shown in FIG.

In step 9, the first filter on the filter 105 side is
The flow path switching valve 106 is opened via the first valve drive device 110. In step 10, the second flow path switching valve 109 on the second exhaust passage 103 side is closed via the second valve drive device 111. In step 11, since the regeneration of the filter 105 is completed, the particulate accumulation amount on the filter 105 is reset to zero.

In step 12, since the reproduction of the filter 105 is completed, the reproduction flag 1 is removed and the present flow ends. As described above, according to the present embodiment, by opening / closing the regeneration exhaust flow rate adjusting valve 108, the regeneration exhaust flow rate V2 at the time of "combustion by heating" is made smaller than the regeneration exhaust flow rate V1 required at the time of "combustion by propagation". Since I tried to reduce it,
During the "combustion by propagation", the regeneration exhaust flow rate V1 corresponding to the combustion can be supplied to optimize the "combustion by propagation", while the particulates left unburned by the "combustion by propagation". Is burned by "combustion by heating", the regeneration exhaust flow rate V2 is adjusted so as not to interfere with the temperature raising action of the electric heater 112, and "combustion by heating" is optimized to completely particulate. Since it can be burnt out, the regeneration of the filter 105 can be optimized by a simple configuration.

In this embodiment, the first flow path switching valve 10
6, bypass passage 107, and regeneration exhaust flow rate control valve 1
08 is provided on the downstream side of the filter 105,
Of course, it may be provided in the first branch passage 102 on the upstream side of the filter 105. Further, in the configuration of the first embodiment shown in FIG. 2, the bypass passage 107 is connected to the filter 1
It is also possible to connect the upstream side and the downstream side of 05 so as to bypass the filter 105. That is,
Not only in the arrangement of the valves and passages in the first embodiment, the flow rate of exhaust gas (oxygen) flowing into the filter 105 is compared with the exhaust gas flow rate flowing into the filter 105 during combustion by propagation.
Any arrangement may be used as long as the exhaust gas flow rate flowing into the filter 105 at the time of combustion by heating can be reduced. Therefore, the opening of the first flow path switching valve 106 or the second flow path switching valve 109 is changed without providing the bypass passage 107 and the regeneration exhaust flow rate adjusting valve 108, and the filter 1
It is also possible to variably control the flow rate of exhaust gas flowing into 05. In this case, the configuration can be further simplified.

In the present embodiment, the on-off valve is used for explanation, but instead of this, an orifice may be adopted and the orifice diameter may be variably controlled to obtain the same effect as that of the present embodiment. Next, a second embodiment according to the present invention will be described. FIG. 11 shows the overall structure of an exhaust particulate treatment system according to a second embodiment of the present invention.

The exhaust passage 101, which is connected to the exhaust manifold of the internal combustion engine 100, is so constructed that, in the middle thereof, it temporarily branches into a first branch passage 102 and a second branch passage 103 and then joins again. . In the first branch passage 102, a filter 10 is installed in a filter case 104 and collects particulates in exhaust gas.
5 is installed. The filter 1 is provided on the upstream side of the filter case 104 in the first branch passage 102.
First flow path switching valve 106 for controlling the amount of exhaust gas flowing into
A is installed.

An air pump 120 is provided for supplying secondary air for regeneration to the filter 105 when the filter 105 is regenerated.
The secondary air for regeneration from 0 is the first flow path switching valve 106.
The air is supplied through a secondary air supply passage 121 opened between A and the filter 105. The air pump 120 is driven via a pump drive device 122 which is controlled by a signal from the control unit 117.

A second flow path switching valve 109A for controlling the amount of exhaust gas flowing into the filter 105 is provided in the middle of the second branch passage 103. The second branch passage 103 is a passage for bypassing and exhausting the filter 105 during regeneration of the filter 105. A first valve drive device 110A that drives the first flow path switching valve 106A to open and close, and a second valve drive device 111A that drives the second flow path switching valve 109A to open and close are provided. These first valve drive device 110A and second valve drive device 111A
Are controlled based on the drive signal from the control unit 117.

Here, the first flow path switching valve 106
A, the control unit 117 constitutes the exhaust gas inflow amount control means according to the present invention. In addition, the air pump 12
0, the secondary air supply passage 121, the control unit 117 and the like constitute the oxygen inflow control means according to the present invention. An electric heater 112 for heating and burning the particulates collected by the filter 105 is provided on the exhaust gas upstream side of the filter 105, and a heater drive circuit 113 for driving the electric heater 112. Is provided. The heater drive circuit 113 is controlled based on a drive signal from the control unit 117.

Here, the electric heater 112 is
The filter temperature raising means according to the present invention is configured. Further, engine operating state detecting means 114 for detecting the operating state of the engine such as the load of the engine, the rotational speed, the cooling water temperature, etc. is provided. Further, an emission amount detection means 115 for detecting / estimating the amount of particulate emissions from the engine, and estimating / detecting the amount of particulate accumulation on the filter 105, the regeneration timing of the filter 105 based on the amount of particulate accumulation. , Accumulation amount detection means 11 for setting the regeneration end time
6 is provided. The discharge amount detecting means 115 and the deposit amount detecting means 116 are provided as software by a microcomputer or the like in the control unit 117.

Now, the operation of the second embodiment will be described. When collecting the particulates by the filter 105, the first flow path switching valve 106A is set to the first valve drive device 110A.
And the second flow path switching valve 109A is closed via the second valve drive device 111A.
05 to let the exhaust gas pass through.

When particulates are deposited on the filter 105 and it is time to regenerate the filter 105, first, the first flow path switching valve 106A on the upstream side of the filter 105.
Is closed via the first valve drive unit 110A, and the second flow path switching valve 109A is opened via the second valve drive unit 111A. As a result, the ventilation resistance on the side of the second branch passage 103 is significantly reduced, while the passage resistance on the side of the first branch passage 102 is increased, so that almost the entire amount of exhaust gas flows through the side of the second branch passage 103. Become. It should be noted that by switching the flow paths in this way, the engine 100 is increased due to an increase in exhaust pressure during regeneration.
The deterioration of the drivability will be prevented.

In this state, the electric heater 112 is electrically heated through the heater driving circuit 113 to regenerate the filter. After energization of the electric heater 112, while the “combustion by propagation” is in progress (that is, from the start of regeneration to the time t1 from completion of combustion propagation, as shown in FIG. 14), the air pump 120. Therefore, as shown in FIGS. 14 and 16, the secondary air V for regeneration required for “combustion by propagation”
Supply 1. As a result, the regeneration of the filter 105 by "combustion by propagation" is favorably performed.

After the "combustion by propagation" is completed,
Until the regeneration ends (that is, from t1 to the end of regeneration), the secondary air V2 for regeneration necessary for “combustion by heating” is supplied from the air pump 120. In this way, the air pump 120 ensures that the oxygen concentration is stable.
Since the secondary air is supplied, the supplied oxygen concentration is controlled with high accuracy, and the combustion by propagation and heating can be performed well, and further, the oxygen concentration is the same as in the first embodiment. Moreover, since it does not depend on the operating state of the engine 100, it is possible to stably obtain high regeneration efficiency.

The detection of the reproduction time / reproduction end time is the same as that in the first embodiment, and the description thereof will be omitted. Next, the filter regeneration control performed by the control unit 117 in the second embodiment will be described with reference to the flowcharts shown in FIGS. Note that steps 1 to 8 shown in FIG. 12 are the same as the flowchart of FIG. 3 described in the first embodiment, so description thereof will be omitted.

After step 8, in the second embodiment, the process proceeds to the flowchart B shown in FIG. That is, in the flowchart B, the filter 10 is used in step 6.
It is judged that it is the regeneration time of No. 5, the first flow path switching valve 106 is closed in step 7, and the second flow path switching valve 10 is closed in step 8.
After opening valve 9, steps 20 to 20 are performed as follows.
Step 26 is executed.

At step 20, as shown in FIG.
Regeneration secondary air amount V1 required for "combustion by propagation"
It is supplied from the air pump 120. The air pump 120
Is driven via the pump drive device 122 based on a signal from the control unit 117. In step 21, the supply of predetermined regeneration power to the electric heater 112 is started via the heater drive circuit 113.

In step 22, it is determined whether the energization time t of the electric heater 112 has reached the end time t1 of "combustion by propagation". In the case of this embodiment, the air pump 1
Since the secondary air amount for regeneration is supplied by 20 as in the first embodiment, the "time required for combustion by propagation" is not affected by the change in the operating state, as shown in FIG.
As shown in FIG. 5, when t = t1, it can be determined that the “combustion by propagation” has ended.

In step 23, as shown in FIG.
Since the energization time t of the electric heater 112 has passed t1, it is determined that the combustion of the particulates due to the propagation has ended, and as shown in FIG. 16, the supply amount of the secondary air for regeneration is set to the pump driving device 122. V1 to V2 via the control valve to adjust to a regeneration exhaust flow rate that is optimal for "combustion by heating". By adjusting the supply amount of the secondary air for regeneration, as shown in FIG. 14, during "combustion by propagation",
Since the secondary air for regeneration corresponding to "combustion by heating" is supplied, it is possible to optimize the particulate combustion speed during each combustion, and thus the good regeneration of the filter 105 can be achieved. Can be done.

In step 24, it is determined whether the energization time t of the electric heater 112 has exceeded a predetermined time t2. In step 25, since the predetermined time t2 has passed,
When the "combustion by heating" is completed, the supply of the secondary air for regeneration is stopped. In step 26, the electric heater 11
2. Stop heating by energization.

When steps 20 to 26 (flow chart B) are completed as described above, the process proceeds to step 9 of the flow chart shown in FIG. 12 again. In step 9, the first flow path switching valve 106 on the filter 105 side is set to the first
Open via valve drive 110. As a result, the exhaust gas passes through the filter 105, so that the particulates are restarted to be collected by the filter 105.

In step 10, the second passage switching valve 109 on the second exhaust passage 103 side is closed via the second valve drive device 111. This is because the inflow of the exhaust gas to the second exhaust passage 103 side is prohibited and the exhaust gas is allowed to flow to the filter 105 side to effectively collect the particulates. In step 11, since the regeneration of the filter 105 is completed, the particulate accumulation amount on the filter 105 is reset to zero.

At step 12, since the reproduction of the filter 105 is completed, the reproduction flag 1 is cleared. As described above, according to the present embodiment, the regeneration exhaust flow rate V2 at the time of "combustion by heating" is made smaller than the regeneration exhaust flow rate V1 required at the time of "combustion by propagation". During the "combustion", the regeneration exhaust flow rate V1 corresponding to the combustion can be supplied to optimize the "combustion by propagation", while the particulates left unburned by the "combustion by propagation" are "heated". In the case of "combustion by heating", the regeneration exhaust flow rate V2 is adjusted so as not to interfere with the temperature raising effect of the electric heater 112, and "burning by heating" is optimized to completely burn out the particulates. Therefore, the regeneration of the filter 105 can be optimized.

Further, in this embodiment, since the secondary air is supplied by the air pump 120, the oxygen concentration to be supplied can be controlled with high accuracy, and the oxygen concentration is the same as in the first embodiment. Since it is not influenced by the operating state of the engine 100, it is possible to stably obtain high regeneration efficiency. In the second embodiment, the one in which the secondary air for regeneration is supplied by the air pump 120 has been described, but in the internal combustion engine including the supercharger, a part of the compressed air of the supercharger is guided. You may make it the structure utilized as secondary air for reproduction | regeneration.

By the way, in each of the above-mentioned embodiments, for easy understanding, the regeneration process is divided into "combustion period due to propagation" and "combustion period due to heating", and regeneration in each period is optimized. However, the present invention is not limited to this, and the amount of oxygen required for regeneration is gradually changed according to the degree of progress of regeneration (e.g., over time, steplessly or divided into a number of steps). Change) (weight loss)
Then, the reproduction may be optimized throughout the reproduction period. In this case, in the first embodiment, each valve is preferably configured by a valve whose opening degree can be controlled.

Further, in each of the above-mentioned embodiments, for easy understanding, the regeneration process is clearly described as being divided into two parts: "combustion period by propagation" and "combustion period by heating". "Combustion period due to propagation" and "Combustion period due to heating" depending on the shape, heat capacity, etc.
In some cases, the combustion time t1 due to propagation may not be strictly set to the combustion time due to propagation, but may be set appropriately so that the required regeneration characteristic is obtained. Absent.

In each of the above embodiments, the oxygen supply amount is controlled so as to maximize the combustion speed in each combustion period in order to give priority to shortening the regeneration time. However, the present invention is not limited to this. In consideration of the durability of the filter, the oxygen amount may be appropriately corrected so that the filter can be regenerated in accordance with the durability. Also,
The "combustion period due to propagation" and the "combustion period due to heating" can be distinguished from each other by methods other than the above-mentioned embodiments, for example, by providing a temperature sensor inside the filter or in the vicinity of the exhaust downstream, and based on the output of the temperature sensor You may make it discriminate.

[0063]

As described above, according to the exhaust gas treating apparatus for the internal combustion engine of the first aspect, the amount of oxygen required for regeneration (combustion) is reduced according to the progress of the regeneration treatment of the filter. Since the correction is performed, the regeneration (combustion) can be optimized throughout the regeneration period of the filter, and thus the regeneration of the filter can be performed with high efficiency.

According to the second aspect of the present invention, the decrease correction of the oxygen inflow amount control means is compared with the oxygen amount per unit time flowing into the filter within a predetermined time from the start of operation of the filter temperature raising means. Since the amount of oxygen per unit time flowing into the filter during the period from the lapse of the predetermined time to the end of the regeneration is reduced by a predetermined amount, the oxygen is collected within the predetermined time from the start of the operation of the filter temperature raising means. During the period when the combustion of the fine particles is active, by controlling the amount of decrease so as to supply a relatively large amount of oxygen commensurate with the combustion, it is possible to optimize the combustion while suppressing the removal of the heat amount. At the same time, when the combustion is relatively inactive from the end of the predetermined time to the end of regeneration, the amount of oxygen can be controlled to be reduced to a relatively small amount of oxygen commensurate with that period. Accordingly, since it is possible to suppress that the heat is carried off to optimize the combustion during the period, it is possible with a simple configuration I than performing regeneration of the filter at high efficiency.

According to the third aspect of the present invention, the predetermined time is set to be a time at which combustion due to propagation is almost completed. Therefore, within a predetermined time from the start of operation of the filter temperature raising means. It is possible to optimize the "combustion by propagation" and the subsequent "combustion by heating" by setting the end of the "combustion by propagation" that is dominant in the combustion of the fine particles of Time wasted,
Therefore, the filter can be regenerated with high efficiency.

According to the fourth aspect of the present invention, the amount of correction is reduced so as to increase the burning speed of the fine particles trapped in the filter, so that the regeneration processing time of the filter can be shortened. According to the invention of claim 5,
Since the oxygen inflow amount control means is a means for controlling the exhaust gas flow rate flowing into the filter, it is not necessary to provide a separate oxygen supply device or the like, and an increase in product cost or the like can be suppressed.

According to the sixth aspect of the present invention, the oxygen inflow amount control means includes the secondary air supply means for supplying the secondary air to the filter. Since the accuracy is improved and it is not affected by the change in the operating condition of the engine, it is possible to stably perform the optimum filter regeneration process.

[Brief description of drawings]

FIG. 1 is a diagram for responding to a claim of the present invention.

FIG. 2 is an overall configuration diagram of an exhaust particulate treatment device for an internal combustion engine according to a first embodiment of the present invention.

FIG. 3 is a flowchart illustrating reproduction control according to the embodiment.

FIG. 4 is a flowchart A for explaining reproduction control according to the embodiment.

FIG. 5 is a diagram for explaining the relationship between the combustion speed and the regenerated exhaust gas flow rate during PM combustion in the above embodiment.

FIG. 6 is a diagram for explaining a relationship between an energization heating time and a PM burning rate in the above embodiment.

FIG. 7 is a diagram for explaining the relationship between energization time and regeneration exhaust gas flow rate in the above embodiment.

FIG. 8 is a diagram for explaining the relationship between the operating state and the combustion end time in the above embodiment.

FIG. 9 is a diagram for explaining the relationship between the operating state during regeneration and the combustion end time due to propagation in the above embodiment.

FIG. 10 is a diagram showing a search map of operating areas and particulate emission amounts in the above-mentioned embodiment.

FIG. 11 is an overall configuration diagram of an exhaust particulate treatment device for an internal combustion engine according to a second embodiment of the present invention.

FIG. 12 is a flowchart illustrating reproduction control according to the embodiment.

FIG. 13 is a flowchart B illustrating reproduction control according to the embodiment.

FIG. 14 is a diagram for explaining the relationship between the combustion speed during PM combustion and the flow rate of secondary air for regeneration in the embodiment.

FIG. 15 is a diagram for explaining the relationship between the energization time and the burning rate of PM in the same example.

FIG. 16 is a diagram for explaining the relationship between the energization time and the flow rate of secondary air for regeneration in the embodiment.

[Explanation of symbols]

 100 Internal Combustion Engine 101 Exhaust Passage 102 First Branch Passage 103 Second Branch Passage 105 Filter 106 First Passage Changeover Valve 107 Bypass Passage 108 Exhaust Flow Rate Control Valve for Regeneration 109 Second Passage Changeover Valve 112 Electric Heater 117 Control Unit 120 Air Pump

Claims (6)

[Claims] 1. A filter which is installed in an exhaust passage of an internal combustion engine and collects fine particles in inflowing exhaust gas, a regeneration timing detecting means for detecting a regeneration timing of the filter, and a filter for raising the temperature of the filter. A temperature raising means; and an exhaust gas inflow amount control means for controlling the amount of exhaust gas flowing into the filter to decrease. When the regeneration timing is detected by the regeneration timing detecting means, the exhaust inflow amount controlling means controls the filter. In an exhaust particulate treatment system of an internal combustion engine, wherein the flow rate of inflowing exhaust gas is controlled to be reduced, and the temperature of the filter is raised by the filter temperature raising means to regenerate the filter. The exhaust gas of an internal combustion engine is provided with an oxygen inflow amount control means for reducing and correcting the oxygen amount flowing into the filter per unit time in accordance with Particle processing apparatus. 2. The oxygen inflow control means compares the amount of oxygen per unit time flowing into the filter within a predetermined time from the start of operation of the filter temperature raising means, between the end of the predetermined time and the end of regeneration. In order to reduce the amount of oxygen per unit time flowing into the filter in
The exhaust particulate treatment system for an internal combustion engine according to claim 1, wherein the amount of oxygen flowing into the filter is corrected to be reduced. 3. The exhaust particulate treatment system for an internal combustion engine according to claim 2, wherein the predetermined time is a time when combustion by propagation is substantially finished. 4. The oxygen inflow control means corrects the amount of oxygen flowing into the filter so as to decrease the amount of oxygen flowing into the filter so as to increase the burning rate of the particulates trapped in the filter. 5. An exhaust particulate treatment device for an internal combustion engine according to any one of 1. 5. The exhaust particulate treatment of an internal combustion engine according to claim 1, wherein the oxygen inflow amount control means is a means for controlling an exhaust flow rate flowing into the filter. apparatus. 6. The oxygen inflow control means is provided to the filter.
The exhaust particulate treatment system for an internal combustion engine according to any one of claims 1 to 5, which is configured to include secondary air supply means for supplying secondary air.