JP2010270613A - Exhaust emission control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent carbon monoxide or active oxygen from being released into the atmosphere when the active oxygen is supplied into an exhaust system. <P>SOLUTION: An upstream exhaust valve 30 and a downstream exhaust valve 32 are provided in the exhaust passage 12 of an internal combustion engine 10. A DPF 14 and an ozone generator 16 are disposed in a sealable passage 12A positioned between the exhaust valves 30, 32. When PM collected by the DPF 14 is oxidized, the exhaust valves 30, 32 are closed, and ozone is supplied from the ozone generator 16 to the sealable passage 12A. Thus, it is possible to keep the gas remaining around the DPF 14 warm by the exhaust valves 30, 32 and to promote PM or CO oxidation reaction through the warm keeping effect. Then, ozone or CO remaining in the exhaust passage 12 is prevented from being released into the atmosphere by the exhaust valves 30, 32. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an exhaust emission control device suitably used for an internal combustion engine, and more particularly to an exhaust emission purification device for an internal combustion engine configured to use active oxygen.

  As a conventional technique, for example, as disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 2007-12097), an exhaust gas purification apparatus for an internal combustion engine configured to supply ozone to an exhaust system is known. A conventional exhaust emission control device includes an EGR passage that recirculates exhaust gas to an intake system, and an ozone supply device that supplies ozone to the EGR passage. In the prior art, when the internal combustion engine is stopped, ozone is supplied to the EGR passage, and the deposits adhered to the EGR cooler and the EGR valve due to particulate matter (PM) in the exhaust gas are oxidized by ozone. The configuration is to be removed.

JP 2007-120297 A

  By the way, in the above-described prior art, ozone is supplied to the exhaust system when the internal combustion engine is stopped. However, during the reaction between ozone and PM, carbon monoxide may be generated due to an incomplete oxidation reaction, and ozone may be excessive. In the prior art, there is a possibility that these carbon monoxide and ozone may be released into the atmosphere from the exhaust passage, and special measures are required to prevent this.

  The present invention has been made to solve the above-described problems. The object of the present invention is to release carbon monoxide and active oxygen into the atmosphere when active oxygen is supplied to the exhaust system. It is an object of the present invention to provide an exhaust emission control device for an internal combustion engine that can prevent exhaust gas and improve exhaust emission.

A first invention is a purification device that is provided in an exhaust passage of an internal combustion engine and purifies unpurified components in exhaust gas;
Downstream passage opening and closing means for opening and closing the exhaust passage on the downstream side of the purification device;
Active oxygen supply means capable of supplying active oxygen to the exhaust passage upstream of the downstream passage opening and closing means;
Purification control means for closing the downstream passage opening and closing means and supplying active oxygen to the exhaust passage by the active oxygen supply means when exhaust gas does not flow through the purification device;
It is characterized by providing.

The second invention comprises an upstream passage opening and closing means for opening and closing the exhaust passage on the upstream side of the supply position of the active oxygen to the exhaust passage and the purification device,
The purification control means is configured to close the upstream passage opening / closing means when supplying active oxygen by the active oxygen supply means.

According to a third aspect of the present invention, there is provided a gas supply amount acquisition means for acquiring an amount of gas supplied to the exhaust passage by the active oxygen supply means,
Supply amount determination means for determining whether or not an amount of gas corresponding to the volume of the portion of the exhaust passage that is blocked by the downstream passage opening / closing means is supplied;
The purification control unit is configured to stop the active oxygen supply unit and close the downstream passage opening / closing unit when the determination of the supply amount determination unit is established.

4th invention, after the supply of the active oxygen by the said active oxygen supply means is stopped, the residual determination means which determines whether active oxygen remains in the gas in the said exhaust passage,
An opening control means for opening the downstream passage opening and closing means when the control by the purification control means is finished and the residual active oxygen in the gas disappears;
It is set as the structure provided with.

5th invention, the required amount calculation means which calculates the required amount of the active oxygen which the said purification apparatus requires,
When the amount of active oxygen supplied by the active oxygen supply means is smaller than the required amount, when the active oxygen in the exhaust passage disappears, the downstream passage opening / closing means is temporarily opened, and the active oxygen supply Replenishment control means for replenishing active oxygen by means;
It is set as the structure provided with.

A sixth invention is provided in the exhaust passage on the upstream side of the downstream passage opening and closing means, and a reflux passage for refluxing the gas flowing out from the purification device to the upstream side of the purification device as a reflux gas;
An air supply means capable of forming a flow of the reflux gas,
The purification control means is configured to stop the active oxygen supply means and operate the air supply means after supplying active oxygen to the exhaust passage by the active oxygen supply means.

A seventh invention is a discharge passage connected to the exhaust passage on the upstream side of the downstream passage opening and closing means for discharging the gas in the exhaust passage to the outside,
A release gas purification catalyst that is provided in the discharge passage and purifies at least active oxygen and carbon monoxide in the gas;
A gas releasing means for releasing the gas in the exhaust passage from the discharge passage to the outside when the control by the purification control means is completed;
It is set as the structure provided with.

  An eighth aspect of the invention is provided with an auxiliary catalyst that is disposed on the upstream side of the downstream passage opening and closing means and that is provided in a passage through which the gas circulated from the purification device flows and purifies at least active oxygen and carbon monoxide in the gas. It is configured.

  A ninth aspect of the invention is configured to include an active catalyst that is provided in a passage that is located upstream of the downstream passage opening / closing means and through which active oxygen flows, and that can increase the activity of the active oxygen.

According to a tenth invention, the active oxygen supply means comprises:
A discharge unit that is provided in a passage to be supplied with active oxygen and capable of generating active oxygen from discharge;
An air supply section for supplying air as a raw material of active oxygen into the passage;
It is set as the structure provided with.

  According to the first invention, the purification control means can supply active oxygen to a portion of the exhaust passage that is closed by the downstream passage opening / closing means. Therefore, the gas staying around the purification device can be kept warm by the downstream passage opening / closing means, and the oxidation reaction between the unpurified components remaining in the purification device and the active oxygen can be promoted by this heat retention effect. As a result, the amount of CO produced by the incomplete oxidation reaction and the amount of unreacted residual active oxygen can be reduced. In addition, the release of residual active oxygen and CO into the atmosphere can be reliably prevented by the downstream passage opening / closing means. Therefore, an apparatus with high exhaust purification performance can be realized, and exhaust emission can be improved.

  According to the second aspect of the present invention, the site for supplying active oxygen in the exhaust passage can be reliably closed on the upstream side and the downstream side. Therefore, for example, even when the upstream side of the exhaust passage communicates with the intake system when the internal combustion engine is stopped, it is possible to reliably prevent active oxygen from entering the intake system. Further, since the volume of the exhaust passage blocked by the two passage opening / closing means can be set to the minimum necessary, the purification process can be performed efficiently by concentrating active oxygen in this small volume.

  According to the third invention, the supply amount determination means determines whether or not an amount of gas corresponding to the volume of the part is supplied to the part of the exhaust passage that is closed by the downstream passage opening / closing means. be able to. Thereby, at the time of supply of active oxygen, the downstream passage opening / closing means can be opened until an amount of gas corresponding to the volume is supplied. Therefore, there is no need to force active oxygen into the closed space, and the active oxygen supply operation can be performed smoothly. The downstream passage opening / closing means can be closed in accordance with the timing when the active oxygen reaches the position of the downstream passage opening / closing means, and the downstream side of the exhaust passage can be closed at an appropriate timing.

  According to the fourth invention, the opening control means can open the downstream passage opening / closing means when the active oxygen remaining in the exhaust passage disappears. Therefore, the oxidation reaction with active oxygen can be sufficiently advanced. And it can prevent reliably that residual active oxygen etc. are discharged | emitted in air | atmosphere.

  According to the fifth aspect of the present invention, the replenishment control means temporarily opens the downstream passage opening / closing means and activates when the active oxygen in the exhaust passage disappears in a state where the supply amount of active oxygen is less than the required amount. Can be supplemented with oxygen. Therefore, the replenishment operation can be repeated until the supply amount reaches the required amount while the active oxygen in an amount corresponding to the volume of the exhaust passage is supplied without difficulty. As a result, the minimum necessary amount of active oxygen can be accurately supplied, and it is possible to reliably prevent excess or deficiency of active oxygen or wasteful power consumption due to excessive generation of active oxygen. Even when a large amount of unpurified component remains in the purifier, the unpurified component can be steadily purified by dividing it into a plurality of times.

  According to the sixth aspect of the invention, the active oxygen supplied to the exhaust passage can be recirculated from the downstream side to the upstream side of the purification device as a recirculation gas. As a result, most of the supplied active oxygen can be repeatedly circulated through the purifier, including the active oxygen that has remained in the exhaust passage at a position away from the purifier. Therefore, active oxygen can be utilized effectively to the maximum, and the oxidation rate of unpurified components can be reliably increased.

  According to the seventh aspect of the present invention, after the unpurified components of the purification device are processed, the gas in the exhaust passage can be purified by the release gas purification catalyst, and the gas can be discharged to the outside from the discharge passage. Therefore, since it is not necessary to wait until the active oxygen remaining in the gas disappears, it is possible to speed up the control.

  According to the eighth invention, even if the supply amount of active oxygen is set according to the amount of the unpurified component, this CO is generated when CO is generated due to the incomplete oxidation reaction of the unpurified component. There will be more active oxygen than that. In this case, the auxiliary catalyst can react CO and active oxygen, and can simultaneously decompose and remove these components. Therefore, it can suppress more reliably that residual active oxygen and CO are discharge | released in air | atmosphere.

  According to the ninth aspect, the activity of active oxygen can be increased by the active catalyst even in a low temperature state. Thereby, oxidation of an unpurified component can be performed efficiently.

  According to the tenth aspect, the discharge part of the active oxygen supply means can directly generate active oxygen in the exhaust passage. Thereby, compared with the case where the active oxygen produced | generated outside, for example is supplied in an exhaust passage, the time until it reacts with an unpurified component after active oxygen production | generation can be shortened. Therefore, the loss of active oxygen due to decomposition or the like during supply can be suppressed to the minimum, and active oxygen and its generated power can be effectively utilized. Further, by incorporating the discharge part into the exhaust passage, the number of parts of the entire system can be reduced, and the size and weight can be reduced.

It is a whole block diagram for demonstrating the system configuration | structure of Embodiment 1 of this invention. FIG. 5 is a characteristic diagram showing a state in which the PM reduction amount and the CO generation amount change according to the catalyst temperature in the oxidation treatment of PM. It is a characteristic diagram which shows the relationship between the decomposition rate of ozone and temperature. In Embodiment 1 of this invention, it is a flowchart which shows the control performed by ECU. In Embodiment 1 of this invention, it is a whole block diagram for demonstrating the system configuration | structure of a modification. It is a whole block diagram for demonstrating the system configuration | structure of Embodiment 2 of this invention. In Embodiment 2 of this invention, it is a flowchart which shows the control performed by ECU. It is a whole block diagram for demonstrating the system configuration | structure of Embodiment 3 of this invention. It is a whole block diagram for demonstrating the system configuration | structure of Embodiment 4 of this invention. It is a whole block diagram for demonstrating the system configuration | structure of Embodiment 5 of this invention. It is a whole block diagram for demonstrating the system configuration | structure of Embodiment 6 of this invention. It is explanatory drawing which shows PM oxidation amount and CO discharge | emission amount about each of the system of Embodiment 6, and a circulation type system. It is explanatory drawing which shows an example of the experimental equipment used in order to verify the effect of this invention. It is explanatory drawing which shows the effect of each embodiment about Embodiment 1 thru | or 4 of this invention.

Embodiment 1 FIG.
[Configuration of Embodiment 1]
The first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is an overall configuration diagram for explaining a system configuration according to the first embodiment of the present invention. The system of the present embodiment includes an internal combustion engine 10 made of, for example, a diesel engine, and a DPF (diesel particulate filter) 14 and an ozone generator 16 are provided in the exhaust passage 12 thereof.

  The DPF 14 collects PM, which is an unpurified component in the exhaust gas, and purifies it by oxidation treatment, and constitutes the purification device of the present embodiment. The ozone generator 16 supplies ozone, which is one of active oxygen, to the upstream side of the DPF 14 in accordance with a control signal input from the ECU 40 described later, and constitutes active oxygen supply means. As the ozone generator 16, for example, a form in which ozone is generated while flowing dry air or oxygen as a raw material in a discharge tube to which a high voltage can be applied, or any other type can be used.

  The ozone generator 16 includes an air intake passage 18 that takes in air that is a raw material of ozone, and an ozone supply passage 20 that supplies the generated ozone to the exhaust passage 12. The air intake passage 18 is provided with an air pump 22 for sucking air, an air amount sensor 24 for detecting the amount of sucked air, and an air filter 26. Here, the air amount sensor 24 constitutes a gas supply amount acquisition means for acquiring the amount of gas supplied to the exhaust passage 12 by the ozone generator 16.

  On the other hand, the ozone supply passage 20 is connected to the exhaust passage 12 at a position between an upstream exhaust valve 30 and a downstream exhaust valve 32 described later and on the upstream side of the DPF 14. In the present embodiment, the ozone supply passage 20 (ozone supply position) is arranged on the upstream side of the DPF 14. However, the present invention is not limited to this, and the ozone supply position is between the exhaust valves 30 and 32. If present, it may be arranged downstream of the DPF 14. The ozone supply passage 20 is provided with a shutoff valve 28 for preventing gas from flowing from the exhaust passage 12 to the ozone generator 16 side. The shut-off valve 28 may be configured by a check valve or the like that prevents backflow in terms of mechanical structure, or may be configured by an electromagnetically driven on-off valve that is controlled to be opened and closed by the ECU 40.

  Further, the exhaust passage 12 includes an upstream exhaust valve 30 as an upstream passage opening / closing means for opening and closing the exhaust passage 12 on the upstream side of the DPF 14 and the ozone supply passage 20, and an exhaust passage 12 on the downstream side of the DPF 14, A downstream exhaust valve 32 as a downstream passage opening / closing means for closing is provided. These exhaust valves 30 and 32 are constituted by electromagnetically driven on-off valves or the like, and are opened and closed by the ECU 40. A portion of the exhaust passage 12 located between the exhaust valves 30 and 32 is a sealable passage 12A that is sealed when the two exhaust valves 30 and 32 are closed. The DPF 14 and the ozone supply passage 20 are disposed in the sealable passage 12A.

  Furthermore, the system of the present embodiment includes a sensor system composed of various sensors necessary for controlling the vehicle and the internal combustion engine, and an ECU (Electronic Control Unit) 40 for controlling the operating state of the internal combustion engine 10. I have. The sensor system includes the air amount sensor 24 described above and a temperature sensor 34 that detects the temperature (floor temperature) of the DPF 14. The sensor system includes, for example, an air flow meter for detecting the intake air amount, a rotation sensor for detecting the output rotation speed (engine rotation speed) of the internal combustion engine, a water temperature sensor for detecting the cooling water temperature of the internal combustion engine, and an exhaust air-fuel ratio. An air-fuel ratio sensor or the like that detects the above is included, and these sensors are connected to the input side of the ECU 40.

  On the other hand, various actuators are connected to the output side of the ECU 40. The actuator includes an ozone generator 16, an air pump 22, exhaust valves 30 and 32, etc., in addition to a fuel injection valve and a spark plug provided in each cylinder. Then, the ECU 40 drives each actuator while detecting the operation state of the internal combustion engine by the sensor system. Specifically, based on the output of the sensor system, the fuel injection amount, injection timing, ignition timing, etc. for each cylinder are set, and the actuator is driven in accordance with these settings. The ECU 40 is configured to execute PM oxidation control described below.

(PM oxidation control)
PM oxidation control uses the oxidizing power of ozone to oxidize the PM collected in the DPF 14 and regenerate the DPF 14. For example, exhaust gas is not circulated through the DPF 14 when the internal combustion engine is stopped. When executed. As a precondition for this control, the temperature of the DPF 14 needs to be equal to or lower than the thermal decomposition temperature of ozone (for example, about 300 ° C.). Even in the prior art, the oxidation treatment of PM with ozone is known, but simply supplying ozone to the exhaust passage 12 releases carbon monoxide and excess ozone generated during oxidation of PM into the atmosphere. There is a fear. For this reason, in this embodiment, ozone is supplied into the sealable passage 12A with the exhaust valves 30 and 32 closed. The exhaust valves 30 and 32 are opened when the oxidation of PM is completed and the ozone in the sealable passage 12A disappears.

  More specifically, in the PM oxidation control, first, the ozone generator 16 (and the air pump 22) is operated with the upstream exhaust valve 30 closed, whereby the gas containing the generated ozone is discharged into the exhaust passage 12 (sealed). To the possible passage 12A). At this time, since the downstream exhaust valve 32 is still held open, a gas containing ozone can be smoothly fed into the sealable passage 12A.

  In addition, the ECU 40 detects the supply amount of the gas supplied into the exhaust passage 12 by the air amount sensor 24 in parallel with the above-described supply operation. When the gas supply amount becomes equal to the volume of the sealable passage 12A stored in advance in the ECU 40 (that is, when the ozone sent into the exhaust passage 12 reaches the position of the downstream exhaust valve 32), ozone generation is performed. The vessel 16 is stopped and the downstream exhaust valve 32 is closed. As a result, ozone is confined in the sealable passage 12A by the two exhaust valves 30 and 32. Therefore, ozone can be concentrated around the DPF 14 and the PM in the DPF 14 can be efficiently oxidized with the minimum amount of ozone.

Here, FIG. 2 is a characteristic diagram showing a state in which the PM reduction amount and the CO generation amount change according to the catalyst temperature in the PM oxidation treatment. In this figure, the amount of PM reduction is the amount by which PM trapped in the DPF is reduced due to the reaction with ozone. The produced CO / CO ₂ ratio represents the ratio of the amount of carbon monoxide and carbon dioxide produced by the reaction between PM and ozone. As shown in FIG. 2, the PM reduction amount tends to decrease on the high temperature side, for example, with a peak at about 200 ° C. In addition, the amount of CO generated tends to increase extremely at a high temperature of 300 ° C., for example.

  Therefore, in this embodiment, the PM oxidation control is executed when the temperature of the DPF 14 (or exhaust gas) detected by the temperature sensor 34 is 300 ° C. or lower. According to this configuration, the amount of CO produced can be suppressed while efficiently reducing the PM in the DPF with ozone. Moreover, by satisfying the above temperature condition, it is possible to suppress the thermal decomposition of ozone as described above and to effectively use ozone.

  Further, after the start of the PM oxidation control, it is determined whether ozone remains in the sealable passage 12A based on the thermal decomposition characteristics of ozone. This determination is made based on the temperature of the DPF 14 and the elapsed time since ozone was supplied into the sealable passage 12A. FIG. 3 is a characteristic diagram showing the relationship between ozone decomposition rate and temperature. This figure shows the decomposition rate of ozone after a certain time has elapsed since ozone was supplied. Since ozone is an unstable compound, it is thermally decomposed at a decomposition rate corresponding to the temperature.

  The ECU 40 stores in advance two-dimensional map data in which the elapsed time after ozone supply is added as a parameter to the characteristic data of FIG. That is, the ECU 40 refers to the two-dimensional map data based on the elapsed time and temperature, thereby obtaining the ozone decomposition rate at that time and calculating the residual amount of ozone. Then, even if the DPF regeneration process is completed, the ECU 40 holds the exhaust valves 30 and 32 in the closed state until it is determined that the ozone in the sealable passage 12A has disappeared. As a result, the reaction between PM and ozone and the reaction between CO and ozone generated by the oxidation of PM can be sufficiently advanced, and then the exhaust valves 30 and 32 can be opened. Therefore, it is possible to reliably prevent CO and residual ozone generated by PM oxidation control from being discharged into the atmosphere.

  On the other hand, when the ozone in the sealable passage 12A disappears, it is determined that the oxidation of PM by the ozone supplied this time has been completed, and then it is determined whether the DPF regeneration process has been completed. That is, when the supply amount of ozone supplied this time is insufficient with respect to the collection amount of PM collected in the DPF 14, even if the ozone in the sealable passage 12A disappears, it is still in the DPF. PM remains. In this case, it is determined that the DPF regeneration process has not been completed, and an ozone replenishment operation (that is, an operation of temporarily opening the downstream exhaust valve 32 and supplying ozone into the sealable passage 12A) is performed. Executed. On the other hand, when the supply amount of ozone supplied this time (in the second and subsequent replenishment operations, the total supply amount of ozone supplied so far) is equal to or greater than the amount of collected PM, the regeneration process of the DPF 14 is completed. And the PM oxidation control is terminated.

  In the determination process described above, the amount of PM trapped can be calculated based on, for example, the pressure difference between the exhaust pressure upstream of the DPF 14 and the exhaust pressure downstream. That is, the ECU 40 stores in advance the pressure difference characteristic data that increases as the amount of collected PM increases. Therefore, the ECU 40 can calculate the amount of collected PM by detecting the pressure difference using a pressure sensor or the like. Further, it is known that carbon and ozone in PM react as shown in the following formula (1) or (2).

C + O ₃ → CO + 1 / 2O ₂ (1)
C + 2O ₃ → CO ₂ + 2O ₂ (2)

  Therefore, the ECU 40 is necessary to complete the regeneration process of the DPF 14 based on the ratio of the reaction amount between PM and ozone obtained by the above equations (1) and (2) and the amount of collected PM described above. The amount of ozone (required amount of ozone) is calculated. Then, when the total supply amount of ozone supplied so far reaches the required amount, it is determined that the regeneration process of the DPF 14 is completed. The supply amount of ozone can be calculated based on the known oxygen concentration in the air and the gas amount (air amount) supplied by the air pump 22.

[Specific Processing for Realizing Embodiment 1]
FIG. 4 is a flowchart showing the control executed by the ECU in the first embodiment of the present invention. The routine shown in this figure is repeatedly executed during operation of the internal combustion engine. In the routine shown in FIG. 4, first, in step 100, it is determined whether there is no flow of exhaust gas flowing in the DPF 14 (in the present embodiment, whether the internal combustion engine is stopped) or not. In the present invention, the execution timing of PM oxidation control is not limited to when the internal combustion engine is stopped. This point will be described in detail with reference to a modification shown in FIG.

  When the determination in step 100 is established, it is determined whether or not the regeneration process of the DPF 14 is necessary based on, for example, the PM collection state by the DPF 14 or the elapsed time since the previous regeneration process was executed (step 102). ). When this determination is established, the amount of PM collected in the DPF 14 is calculated as described above, and the required amount of ozone corresponding to this amount of collection is calculated (steps 104 and 106). Further, when the determination is not established in any of steps 100 and 102, the process returns without executing the PM oxidation control.

  Next, it is determined whether or not the temperature of the DPF 14 (or exhaust gas) is 300 ° C. or less (step 108). When this determination is established, the upstream exhaust valve 30 is closed, and the ozone generator 16 and the air pump 22 are operated (steps 110 and 112). Thereby, the gas containing ozone is supplied from the ozone generator 16 into the sealable passage 12A. At this time, the ECU 40 waits until this determination is satisfied while determining whether or not the gas supply amount (discharged gas amount of the air pump 22) is equal to the previously stored volume of the sealable passage 12A (step). 114).

  When the determination in step 114 is established, the ozone generator 16 and the air pump 22 are stopped to stop the supply of ozone to the sealable passage 12A, and the downstream exhaust valve 32 is closed (step 116). As a result, the sealable passage 12A is sealed by the two exhaust valves 30 and 32, and the reaction between PM and ozone proceeds in the interior, so that the ECU 40 oxidizes the PM (the ozone While determining whether or not (decomposition) has ended, the process waits until this determination is satisfied (step 118).

  Next, when the determination in step 118 is established, it is determined whether or not the regeneration process of the DPF 14 is completed (step 120). That is, in step 120, it is determined whether or not the amount of ozone supplied by the ozone generator 16 has reached the required amount of ozone calculated in step 106. When this determination is established, the PM oxidation process is completed and no ozone remains in the sealable passage 12A. Therefore, the two exhaust valves 30 and 32 are opened, and the PM oxidation control is finished (step). 122).

  Further, when the determination in step 120 is not satisfied, the supply amount of ozone to the DPF 14 is insufficient, so the downstream exhaust valve 32 is opened to replenish ozone in the sealable passage 12A (step 124). And the process of steps 112-120 is repeatedly performed until the total supply amount of ozone reaches the said required amount.

  As described above in detail, according to the present embodiment, when PM oxidation control is performed, ozone can be supplied to the sealable passage 12A sealed by the exhaust valves 30 and 32. Therefore, the gas staying around the DPF 14 can be kept warm by the exhaust valves 30 and 32, and the oxidation reaction of PM can be promoted by this heat keeping effect. As a result, the amount of CO produced by the incomplete oxidation reaction and the amount of ozone remaining unreacted can be reduced. In addition, the exhaust valves 30 and 32 can reliably prevent residual ozone and CO from being released into the atmosphere. Therefore, an apparatus with high exhaust purification performance can be realized, and exhaust emission can be improved.

  Further, the above effect can be sufficiently obtained by using only the downstream exhaust valve 32, but a more remarkable effect can be obtained by using the two exhaust valves 30 and 32. More specifically, depending on the structure of the internal combustion engine 10, the upstream side of the exhaust passage 12 may be in communication with the intake system when the engine is stopped. However, by providing the upstream exhaust valve 30, the sealable passage 12A can be reliably closed on the upstream side and the downstream side, and the residual ozone or the like can be reliably prevented from entering the intake system. Further, since the volume of the sealable passage 12A can be set to the minimum necessary by the two exhaust valves 30 and 32, it is possible to efficiently oxidize PM by concentrating ozone in the small volume.

  In the present embodiment, the downstream exhaust valve 32 is closed when an amount of gas corresponding to the volume of the sealable passage 12A is supplied from the ozone generator 16. Thereby, when supplying ozone, it is not necessary to force ozone into the sealed space, so that the supplying operation can be performed smoothly. Then, the downstream exhaust valve 32 can be reliably closed at the timing when ozone reaches the position of the downstream exhaust valve 32, and the sealable passage 12 can be closed at an appropriate timing.

  Furthermore, in the present embodiment, when ozone in the sealable passage 12A disappears in a state where the supply amount of ozone is less than the required amount, the downstream exhaust valve 32 may be temporarily opened to replenish ozone. it can. Therefore, the replenishment operation can be repeated until the amount of ozone supplied reaches a required amount while the amount of ozone corresponding to the volume of the sealable passage 12A is reasonably supplied. As a result, it is possible to accurately supply the minimum amount of ozone corresponding to the amount of collected PM, etc., and it is ensured that excess or shortage of ozone will occur or wasteful power will be consumed due to excessive generation of ozone. Can be prevented. And even when a large amount of PM is collected in the DPF 14, this PM can be oxidized steadily in a plurality of times.

  In the present embodiment, the PM oxidation control is performed when the internal combustion engine is stopped. However, the present invention is also applied to a configuration in which the PM oxidation control is performed during the operation of the internal combustion engine, for example, as shown in FIG. It is what is done. Here, FIG. 5 is an overall configuration diagram for describing a system configuration of a modified example in the first embodiment of the present invention. In this modification, the exhaust passage 12 is provided with a bypass passage 36 that bypasses the DPF 14 and the downstream exhaust valve 32. The upstream side of the bypass passage 36 is connected to the exhaust passage 12 via, for example, an upstream exhaust valve 30 '. The upstream exhaust valve 30 ′ is configured by, for example, an electromagnetically driven three-way valve or the like, and the exhaust gas flow path can be switched between the sealable passage 12 </ b> A and the bypass passage 36. According to this modification, PM oxidation control can be performed by closing the downstream exhaust valve 32 and allowing the exhaust gas to flow through the bypass passage 36 even during operation of the internal combustion engine.

  Further, in the modification shown in FIG. 5, a DPF may be provided in the bypass passage 36 in order to prevent PM in the exhaust gas from being released into the atmosphere through the bypass passage 36. Further, ozone may be supplied to this DPF in order to oxidize and remove PM of the DPF in the bypass passage 36. In this case, the downstream exhaust valve 32 may be an electromagnetically driven three-way valve similar to the upstream exhaust valve 30 ′, and the downstream portion of the bypass passage 36 may be connected to the downstream exhaust valve. According to this configuration, by switching between the upstream exhaust valve 30 ′ and the downstream exhaust valve each configured by an electromagnetically driven three-way valve, either one of the sealable passage 12 </ b> A and the bypass passage 36 is alternately arranged. A sealed passage is formed, and PM can be oxidized and removed by ozone in the sealed passage.

Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described with reference to FIGS. The present embodiment includes a reflux passage for refluxing gas from the downstream side to the upstream side of the DPF, and the configuration is different from that of the first embodiment including this point. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

[Features of Embodiment 2]
FIG. 6 is an overall configuration diagram for explaining a system configuration according to the second embodiment of the present invention. The system of the present embodiment includes a reflux passage 50, a reflux pump 52, a shutoff valve 54, and the like in addition to the configuration of the first embodiment. The recirculation passage 50 is a passage for recirculating gas from the downstream side to the upstream side of the DPF 14 in the sealable passage 12A, and is parallel to the DPF 14 with respect to the exhaust passage 12 at a position upstream of the downstream exhaust valve 32. It is connected.

  More specifically, one end side of the recirculation passage 50 is connected between the upstream exhaust valve 30 and the DPF 14, and the other end side of the recirculation passage 50 is connected between the DPF 14 and the downstream exhaust valve 32. Yes. The reflux passage 50 is provided with the same ozone generator 16 as in the first embodiment, and the ozone supply passage 20 constitutes a part of the reflux passage 50. However, in the present embodiment, the ozone generator 16 has a function of supplying ozone to the ozone supply passage 20 and a function of passing the gas flowing through the reflux passage 50 as it is when the supply of ozone is stopped.

  The reflux pump 52 is configured by an air supply unit such as a pump and a fan, and is provided in the reflux passage 50. The recirculation pump 52 operates in response to a control signal input from the ECU 40, and forms a recirculation gas flow between the exhaust passage 12 (sealable passage 12 </ b> A) and the recirculation passage 50. On the other hand, the shut-off valve 54 is configured by an electromagnetically driven on-off valve or the like driven by the ECU 40, and is provided on the other end side (the end opposite to the shut-off valve 28) of the reflux passage 50. The shut-off valve 54 is held in a closed state during operation of the internal combustion engine, and prevents exhaust gas from flowing into the recirculation passage 50.

(PM oxidation control)
In the present embodiment, the PM oxidation control is executed according to substantially the same procedure as in the first embodiment. However, after supplying ozone to the sealable passage 12A, the shutoff valve 54 is opened and the reflux pump 52 is operated. As a result, the gas in the sealable passage 12A flows along the annular flow path composed of the reflux passage 50 and the sealable passage 12A, and is refluxed from the downstream side of the DPF 14 to the upstream side. This reflux operation is continued until PM oxidation is completed. Thereby, residual ozone and CO in the reflux gas can be reliably purified while effectively using ozone.

[Specific Processing for Realizing Embodiment 2]
FIG. 7 is a flowchart showing the control executed by the ECU in the second embodiment of the present invention. The routine shown in this figure is obtained by adding steps 130 and 132 to the routine (FIG. 4) of the first embodiment. Therefore, in the following description, the description of the same processing as that of the first embodiment is omitted.

  In the routine shown in FIG. 7, first, by performing the processing of steps 100 to 116, an appropriate amount of ozone is supplied to the sealable passage 12 </ b> A, and the downstream exhaust valve 32 is closed. In step 130, the reflux pump 52 is operated and the shutoff valve 54 is opened. The other shut-off valve 28 is constituted by a check valve that allows the flow of gas in the recirculation direction. However, when an electromagnetically driven on-off valve or the like is used as the shut-off valve 28, 2 in step 130 is used. The two shutoff valves 28 and 54 may be opened. At the end of PM oxidation, the reflux pump 52 is stopped and the shutoff valve 54 is closed (step 132).

  In the present embodiment configured as described above, it is possible to obtain substantially the same operational effects as in the first embodiment. In particular, according to the present embodiment, during the PM oxidation control, ozone supplied to the sealable passage 12A can be recirculated from the downstream side to the upstream side of the DPF 14 as a reflux gas. As a result, most of the supplied ozone can be repeatedly circulated through the DPF 14, including ozone and the like remaining at a position away from the DPF 14. Therefore, ozone can be utilized to the maximum extent and PM can be oxidized efficiently.

  In addition, the gas flowing through the reflux passage 50 passes through the inside of the ozone generator 16 (discharge tube) that generates heat when ozone is generated. Therefore, even if the reflux gas contains residual ozone or CO, the high temperature atmosphere in the discharge tube can accelerate the thermal decomposition of ozone and the oxidation reaction of CO, and these components are released into the atmosphere. Can be reliably suppressed.

Embodiment 3 FIG.
Next, a third embodiment of the present invention will be described with reference to FIG. The present embodiment includes an auxiliary catalyst for purifying at least active oxygen and carbon monoxide, and is characterized by this point. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

[Features of Embodiment 3]
FIG. 8 is an overall configuration diagram for explaining a system configuration according to the third embodiment of the present invention. The system of the present embodiment includes a reflux passage 50, a reflux pump 52, and a shutoff valve 54 similar to those of the second embodiment, and is configured to execute PM oxidation control by the same procedure as that of the second embodiment. . The reflux passage 50 is provided with an oxidation catalyst 56 as an auxiliary catalyst. The oxidation catalyst 56 is disposed at a position downstream of the DPF 14 and upstream of the ozone generator 16 with respect to the flow direction of the reflux gas. The oxidation catalyst 56 is composed of, for example, an Ag catalyst containing silver as a catalyst component, a catalyst in which a metal such as Pt is supported on γ-alumina, and the like, and can efficiently oxidize CO in the presence of ozone. ing.

  In this embodiment configured as described above, it is possible to obtain substantially the same operational effects as in the second embodiment. In particular, according to the present embodiment, ozone and CO in the gas can be simultaneously removed by the oxidation catalyst 56 during PM oxidation control. That is, in PM oxidation control, an amount of ozone corresponding to the amount of PM collected is supplied, but if CO is generated due to incomplete oxidation of PM, ozone is left by the amount generated by this CO. become. In this case, the oxidation catalyst 56 can react CO and ozone in the gas, and can simultaneously decompose and remove these components from the gas. Therefore, it can suppress more reliably that residual ozone and CO are discharge | released in air | atmosphere.

Embodiment 4 FIG.
Next, a fourth embodiment of the present invention will be described with reference to FIG. The present embodiment includes an active catalyst for increasing the activity of active oxygen, and is characterized by this point. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

[Features of Embodiment 4]
FIG. 9 is an overall configuration diagram for explaining a system configuration according to the fourth embodiment of the present invention. The system of the present embodiment includes a reflux passage 50, a reflux pump 52, and a shutoff valve 54 similar to those of the second embodiment. An active catalyst 58 capable of activating ozone is provided in the ozone supply passage 20 that constitutes a part of the reflux passage 50.

  In general, ozone has a high stability at a low temperature below a predetermined activation reference temperature (for example, about 150 ° C.), and the oxidation efficiency of PM tends to decrease. In this low temperature state, the active catalyst 58 can moderately destabilize (radicalize) ozone and increase its oxidation reactivity. Specifically, the active catalyst 58 can be a noble metal such as Pt, Pd, Rh, or Ag, a transition metal such as Fe, Mn, Co, or Zr or an oxide thereof, a rare earth element or an oxide thereof, or Al. The catalyst contains at least one oxide of Si.

  The active catalyst 58 is disposed at a position downstream of the ozone generator 16 and upstream of the DPF 14 with respect to the flow direction of the reflux gas, that is, a position where ozone flowing out from the ozone generator 16 flows toward the DPF 14. Has been. Accordingly, the ozone generated by the ozone generator 16 is configured to flow into the DPF 14 while being activated by the active catalyst 58.

  On the other hand, when the temperature is higher than the above-described activation reference temperature, the reactivity of ozone is sufficiently high, so that it is not necessary to use the active catalyst 58. Therefore, the reflux passage 50 is provided with a bypass passage 60 that bypasses the active catalyst 58 and a flow path switching valve 62 that switches the flow path of the reflux gas to either the active catalyst 58 or the bypass passage 60. The flow path switching valve 62 is configured by an electromagnetically driven three-way valve or the like. The ECU 40 determines whether or not the temperature of the DPF 14 (or exhaust gas) is equal to or lower than the activation reference temperature when performing PM oxidation control, and switches and controls the flow path switching valve 62 based on the determination result. It is configured as follows.

  Further, in the present embodiment, the PM oxidation control is executed by the same procedure as in the second embodiment except for the switching control of the flow path switching valve 62. In the switching control, the flow path of the reflux gas is switched to the active catalyst 58 side by the flow path switching valve 62 when the temperature is lower than the activation reference temperature. As a result, the ozone supplied from the ozone generator 16 to the reflux passage 50 and the ozone flowing through the reflux passage 50 flow into the DPF 14 while being activated by the active catalyst 58. On the other hand, in a state higher than the activation reference temperature, the flow path of the reflux gas is switched to the bypass path 60 by the flow path switching valve 62. As a result, ozone does not pass through the active catalyst 58 but is recirculated through the bypass passage 60.

  In the present embodiment configured as described above, substantially the same operational effects as those of the second embodiment can be obtained. And especially according to this Embodiment, since it was set as the structure provided with the active catalyst 58, oxidation of PM can be performed efficiently also in the low temperature state where the activity of ozone falls. Further, in a high temperature state where the active catalyst 58 is not required, the reflux gas can be circulated through the bypass passage 60, so that thermal degradation of the active catalyst 58 can be suppressed.

Embodiment 5 FIG.
Next, a fifth embodiment of the present invention will be described with reference to FIG. The present embodiment is provided with a discharge passage for discharging the gas generated during the oxidation of PM to the outside, and is characterized by this point. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

[Features of Embodiment 5]
FIG. 10 is an overall configuration diagram for explaining a system configuration according to the fifth embodiment of the present invention. The system according to the present embodiment includes a discharge passage 70 for discharging the gas in the exhaust passage 12 (sealable passage 12A) to the outside. Here, the discharge passage 70 is constituted by the air intake passage 18 of the ozone generator 16 and the ozone supply passage 20, and is connected to the sealable passage 12 </ b> A on the upstream side of the downstream exhaust valve 32. That is, in the present embodiment, the air intake passage 18 and the ozone supply passage 20 of the ozone generator 16 are shared as the discharge passage 70. For this reason, in addition to the normal ozone generation function, the ozone generator 16 also has a function of allowing the gas released from the sealable passage 12A to pass outside.

  The air pump 72 provided in the air intake passage 18 is a combination of the gas discharge means of the present embodiment and the air pump for the ozone generator 16 and is constituted by an electric pump that can rotate forward and backward. Has been. That is, the air pump 72 can perform an operation of sucking outside air toward the ozone generator 16 by rotating forward and an operation of sucking the gas in the sealable passage 12A to the outside by rotating backward. These operations are switched according to a control signal input from the ECU 40.

  Further, an oxidation catalyst 74 as a discharge gas purification catalyst is provided in the discharge passage 70 (air intake passage 18). The oxidation catalyst 74 is configured to purify at least ozone and CO in the gas, as in the third embodiment. Since the oxidation catalyst 74 is disposed upstream of the ozone generator 16 in the air suction direction, the ozone generated by the ozone generator 16 does not pass through the oxidation catalyst 74 and can be sealed 12A. To be supplied. Therefore, the ozone supply operation can be prevented from being affected by the oxidation catalyst 74.

  The ozone supply passage 20 is provided with a shut-off valve 76 constituted by an electromagnetically driven on-off valve or the like. The shutoff valve 76 is opened by the ECU 40 when the ozone supply operation and the gas suction operation in the sealable passage 12A are executed. The shutoff valve 76 is held in a closed state during normal operation of the internal combustion engine, and shuts off exhaust gas from flowing into the discharge passage 70.

  In the present embodiment, the PM oxidation control is executed in substantially the same procedure as in the first embodiment. However, when the regeneration of the DPF 14 is completed, the operation of sucking out the gas staying in the sealable passage 12A is performed. More specifically, in this suction operation, the downstream exhaust valve 32 is opened and the air pump 72 is rotated in the reverse direction. As a result, the gas in the sealable passage 12A is released into the atmosphere from the discharge passage 70, and air is introduced into the sealable passage 12A via the downstream exhaust valve 32. At this time, residual ozone and CO in the released gas are purified by the oxidation catalyst 74, so that these components can be prevented from being released into the atmosphere.

  Further, the duration of the suction operation is set in advance so as to be at least a time length during which the gas in the sealable passage 12A can be replaced based on the flow rate of the air pump 72 and the volume of the sealable passage 12A. . And when this continuation time passes or it is confirmed by ozone sensor, CO sensor, etc. that residual ozone and CO do not exist in the sealable passage 12A, the air pump 72 is stopped.

  The above suction operation may be performed when ozone is detected by the residual ozone determination process (step 118 in FIG. 4) similar to that in the first embodiment, for example, and may not be performed in other cases. . The suction operation may be performed when the internal combustion engine is restarted. That is, for example, when PM oxidation control is executed when the internal combustion engine is stopped, residual ozone or CO may exist in the sealable passage 12A. For this reason, when the internal combustion engine is restarted (immediately before restart), for example, the above-described suction operation may be performed when these components are detected by an ozone sensor, a CO sensor, or the like.

  In the present embodiment configured as described above, it is possible to obtain substantially the same operational effects as in the first embodiment. And especially according to this Embodiment, even if it does not wait until residual ozone lose | disappears, it can discharge | release quickly, purifying the gas in 12 A of sealable paths, and can aim at speeding-up of control. it can. In the present embodiment, since the air intake passage 18 and the ozone supply passage 20 of the ozone generator 16 are shared as the discharge passage 70, a dedicated discharge passage, a gas discharge pump, and the like are installed. Therefore, the system can be reduced in size and simplified.

  The present invention is not limited to the configuration of the fifth embodiment described above, and the discharge passage 70 does not necessarily need to be shared with the air intake passage 18 and the ozone supply passage 20. That is, in the present invention, for example, a dedicated discharge passage is connected to the sealable passage 12A separately from the air intake passage 18 and the ozone supply passage 20, and a gas discharge means such as a pump and a discharge gas purification device are connected to the discharge passage. It is good also as a structure which provides a catalyst.

Embodiment 6 FIG.
Next, a sixth embodiment of the present invention will be described with reference to FIGS. The present embodiment is characterized in that the discharge portion of the active oxygen supply means is provided in the gas passage, and this is a feature. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

[Features of Embodiment 6]
FIG. 11 is an overall configuration diagram for explaining a system configuration according to the sixth embodiment of the present invention. The system of the present embodiment includes an ozone generator 80 as an active oxygen supply unit having the same function as that of the first embodiment. The ozone generator 80 includes a power supply circuit 82 that generates a high voltage pulse when power is supplied from a power supply, a discharge unit 84 that discharges when the high voltage pulse is supplied, and ozone discharges to the discharge unit 84. And an air supply unit 86 for supplying air as a raw material.

  Here, the discharge unit 84 includes two electrodes provided in the exhaust passage 12 (the sealable passage 12A) on the upstream side of the DPF 14. A discharge is generated between these electrodes by applying a high voltage pulse from the power supply circuit 82. In the presence of air (oxygen), ozone is generated in the sealable passage 12A by this discharge. The air supply unit 86 includes an air pump similar to that of the first embodiment, and the discharge port of the air pump is connected to the sealable passage 12A on the upstream side of the discharge unit 84. And the air supply part 86 is comprised so that the air used as the raw material of ozone may be supplied in 12A of sealable paths. Further, in the present embodiment, PM oxidation control is executed by substantially the same procedure as in the first embodiment.

  In the present embodiment configured as described above, it is possible to obtain substantially the same operational effects as in the first embodiment. In particular, according to the present embodiment, ozone can be directly generated in the sealable passage 12 </ b> A by the discharge portion 84. Thereby, compared with the case where ozone generated outside, for example, is supplied into the sealable passage 12A, the time from when ozone is generated until it reacts with PM can be shortened. Therefore, the loss of ozone due to decomposition or the like during supply can be suppressed to the minimum, and ozone and its generated power can be used effectively.

  FIG. 12 is an explanatory diagram showing the PM oxidation amount and the CO emission amount for each of the system of the sixth embodiment and the circulation type system. In this figure, “circulation type” indicates the system configuration of the second embodiment provided with the reflux passage 50. Further, the data shown in FIG. 12 is obtained by the experiment of the present inventor. As shown in FIG. 12, the configuration of the present embodiment can also exhibit the PM oxidation capability and the CO purification capability that are almost the same as those of the second embodiment. Therefore, according to the present embodiment, even with a simple structure that does not use a recirculation passage or the like, high exhaust purification performance can be realized by incorporating the discharge portion 84 into the exhaust passage 12. Thereby, the number of parts, such as piping parts, can be reduced and the whole system can be reduced in size and weight.

(Verification by experiment)
Next, the effects of the first to fourth embodiments will be described with reference to FIGS. 13 and 14. First, FIG. 13 is explanatory drawing which shows an example of the experimental equipment used in order to verify the effect of this invention. In this experimental facility, an evaluation sample containing DPF is accommodated in a cylindrical container corresponding to the exhaust passage 12 (sealable passage 12A), and gas containing ozone can be circulated in the container. It has become. Further, both end sides of the container are sealed with shielding plates corresponding to the exhaust valves 30 and 32.

  As an evaluation sample to be accommodated in a container, for example, a slurry in which 1 wt% Pt is supported on γ alumina is coated at a rate equivalent to 50 g / L with respect to a 35 cc DPF, and 0.3 g is applied to this DPF. The PM was attached. In the experiment corresponding to the first embodiment, after the ozone-containing gas is retained in the container, the oxidation amount of PM and the generation amount of CO are measured. Further, in the experiment corresponding to the second and third embodiments, as shown in FIG. 13, the gas containing ozone is recirculated from the downstream side to the upstream side of the container, or the auxiliary catalyst sample is arranged on the gas recirculation path. The configuration is as follows. As a sample of the auxiliary catalyst, a material in which a metal such as Pt is supported on γ alumina is used. Moreover, each experiment was implemented in the state which warmed DPF to about 200 degreeC.

  Data obtained by the above experiment is shown in FIG. FIG. 14 is an explanatory diagram showing the effects of the respective embodiments of the first to fourth embodiments of the present invention. In this figure, “sealed type” indicates experimental data corresponding to the first embodiment. Further, “circulation type” corresponds to the second embodiment, and “circulation type + auxiliary catalyst” corresponds to the third embodiment. The “comparative example” corresponds to the prior art, and is experimental data when the exhaust valves 30 and 32 are not installed (when the above-described shielding plate is not present). As can be seen from FIG. 14, according to the first to fourth embodiments, the amount of PM oxidation can be reliably increased as compared with the prior art, and the exhaust emission can be improved. Moreover, when an auxiliary catalyst is used, the amount of CO emission can be suppressed.

  In the above embodiment, steps 112, 116, and 130 in FIGS. 4 and 7 show specific examples of the purification control means. Step 114 shows a specific example of the supply amount determination means, step 118 shows a specific example of the residual determination means, and step 122 shows a specific example of the opening control means. Further, step 106 shows a specific example of the requested amount calculation means, and steps 112 and 124 show specific examples of the replenishment control means.

  In the embodiment, the exhaust passage 12 is provided with the upstream exhaust valve 30 and the downstream exhaust valve 32. However, the present invention only requires at least the downstream exhaust valve 32 of the exhaust valves 30 and 32, and does not necessarily require the upstream exhaust valve 30. When the upstream exhaust valve 30 is omitted, “the volume of the portion of the exhaust passage that is blocked by the downstream passage opening / closing means” refers to, for example, the exhaust passage of the internal combustion engine from the exhaust valve of the internal combustion engine (downstream exhaust opening / closing means). The passage volume up to the valve 32) may be considered.

  In the first embodiment, as a modification shown in FIG. 5, a configuration capable of executing PM oxidation control even during operation of the internal combustion engine is illustrated. The present invention may be configured to apply this modification to the second to sixth embodiments. Thereby, also in Embodiment 2 thru | or 6, PM oxidation control can be performed during engine operation.

  In the third and fourth embodiments, the oxidation catalyst 56 and the active catalyst 58 are used, respectively. In the present invention, these catalysts 56 and 58 can also be used in other embodiments. That is, for example, in Embodiments 1, 4, 5, and 6, the oxidation catalyst 56 may be provided in the sealable passage 12A. In the first, third, fifth, and sixth embodiments, the active catalyst 58 may be provided in the ozone supply passage 20 or the sealable passage 12A.

  Furthermore, in the sixth embodiment, the discharge part 84 of the ozone generator 80 is arranged in the sealable passage 12A. In the present invention, for example, in the second, third, fourth, and fifth embodiments, the discharge portion 84 may be provided in the sealable passage 12A or the reflux passage 50.

  In the embodiment, a configuration is used in which the pressure difference between the upstream side and the downstream side of the DPF 14 is changed according to the amount of collected PM, and the amount of collected PM is detected based on the pressure difference. . However, the present invention is not limited to this. For example, the amount of PM collected (accumulated amount) collected in the DPF 14 is integrated according to the operating state of the internal combustion engine, and the amount of PM collected according to the integrated value. It is good also as a structure which estimates quantity.

In the embodiment, ozone has been described as an example of the active oxygen added to the exhaust gas. However, the present invention is not limited to this, and instead of ozone, other types of active oxygen (for example, oxygen negative ions represented by O ⁻ , O ²⁻ , O ₂ ⁻ , O ₃ ⁻ , O _n ^−, etc.) are used. ) May be added to the exhaust gas.

  In the embodiment, the DPF 14 is described as an example of the purification device. However, the present invention is not limited to the DPF, and can be widely applied to various catalysts and purification mechanisms that purify components in the exhaust gas.

  Furthermore, in the embodiment, the case where the present invention is applied to the internal combustion engine 10 including a diesel engine has been described as an example. However, the present invention is not limited to this, and is widely applied to various internal combustion engines including, for example, a gasoline engine. To get.

10 Internal combustion engine 12 Exhaust passage 12A Sealable passage 14 DPF (purification device)
16, 80 Ozone generator (active oxygen supply means)
18 Air intake passage 20 Ozone supply passage 22 Air pump 24 Air amount sensor (gas supply amount acquisition means)
26 Air filter 28, 54 Shut-off valve 30, 30 'Upstream exhaust valve (upstream passage opening / closing means)
32 Downstream exhaust valve (downstream passage opening / closing means)
34 Temperature sensor 36, 60 Bypass passage 40 ECU
50 Reflux passage 52 Reflux pump (air supply means)
56 Oxidation catalyst (auxiliary catalyst)
58 Active catalyst 62 Flow path switching valve 70 Release passage 72 Air pump (gas release means)
74 Oxidation catalyst (exhaust gas purification catalyst)
82 Power supply circuit 84 Discharge unit 86 Air supply unit

Claims (10)

A purification device provided in an exhaust passage of the internal combustion engine for purifying unpurified components in the exhaust gas;
Downstream passage opening and closing means for opening and closing the exhaust passage on the downstream side of the purification device;
Active oxygen supply means capable of supplying active oxygen to the exhaust passage upstream of the downstream passage opening and closing means;
Purification control means for closing the downstream passage opening and closing means and supplying active oxygen to the exhaust passage by the active oxygen supply means when exhaust gas does not flow through the purification device;
An exhaust emission control device for an internal combustion engine, comprising: An upstream passage opening / closing means for opening and closing the exhaust passage upstream of the purification oxygen supply position and the supply position of the active oxygen to the exhaust passage;
The exhaust purification device for an internal combustion engine according to claim 1, wherein the purification control means is configured to close the upstream passage opening / closing means when the active oxygen is supplied by the active oxygen supply means. Gas supply amount acquisition means for acquiring the amount of gas supplied to the exhaust passage by the active oxygen supply means;
Supply amount determination means for determining whether or not an amount of gas corresponding to the volume of the portion of the exhaust passage that is blocked by the downstream passage opening / closing means is supplied;
The internal combustion engine according to claim 1 or 2, wherein the purification control means is configured to stop the active oxygen supply means and close the downstream passage opening / closing means when the determination of the supply amount determination means is established. Exhaust purification device. Residual determination means for determining whether or not active oxygen remains in the gas in the exhaust passage after the supply of active oxygen by the active oxygen supply means is stopped;
An opening control means for opening the downstream passage opening and closing means when the control by the purification control means is finished and the residual active oxygen in the gas disappears;
The exhaust emission control device for an internal combustion engine according to any one of claims 1 to 3, further comprising: A required amount calculating means for calculating a required amount of active oxygen required by the purification device;
When the amount of active oxygen supplied by the active oxygen supply means is smaller than the required amount, when the active oxygen in the exhaust passage disappears, the downstream passage opening / closing means is temporarily opened, and the active oxygen supply Replenishment control means for replenishing active oxygen by means;
The exhaust emission control device for an internal combustion engine according to any one of claims 1 to 4, further comprising: A reflux passage provided in the exhaust passage on the upstream side of the downstream passage opening and closing means, and refluxing the gas flowing out from the purification device to the upstream side of the purification device as a reflux gas;
An air supply means capable of forming a flow of the reflux gas,
6. The purification control unit according to claim 1, wherein the purification control unit is configured to stop the active oxygen supply unit and operate the air supply unit after supplying active oxygen to the exhaust passage by the active oxygen supply unit. An exhaust purification device for an internal combustion engine according to claim 1. A discharge passage connected to the exhaust passage on the upstream side of the downstream passage opening and closing means for discharging the gas in the exhaust passage to the outside;
A release gas purification catalyst that is provided in the discharge passage and purifies at least active oxygen and carbon monoxide in the gas;
A gas releasing means for releasing the gas in the exhaust passage from the discharge passage to the outside when the control by the purification control means is completed;
An exhaust purification device for an internal combustion engine according to any one of claims 1 to 6, further comprising:   The auxiliary catalyst for purifying at least active oxygen and carbon monoxide in the gas is provided in a passage through which the gas circulated from the purification device is located upstream of the downstream passage opening / closing means. An exhaust purification device for an internal combustion engine according to claim 1, wherein:   9. The active catalyst according to claim 1, further comprising an active catalyst provided in a passage through which the active oxygen flows and located upstream of the downstream passage opening / closing means, and capable of increasing the activity of the active oxygen. 2. An exhaust gas purification apparatus for an internal combustion engine according to 1. The active oxygen supply means includes
A discharge unit that is provided in a passage to be supplied with active oxygen and capable of generating active oxygen from discharge;
An air supply section for supplying air as a raw material of active oxygen into the passage;
The exhaust emission control device for an internal combustion engine according to any one of claims 1 to 9, further comprising:

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