JP2019127834A - Ozone supply device and ozone control device - Google Patents

Abstract

To provide an ozone supply device and an ozone control device that can restrain ozone from being released to the outside from an exhaust passage.SOLUTION: An ozone supply device 30 for supplying ozone to an exhaust passage 15 comprises an ozone passage 31, an ozonizer 32, an air pump 33, and an ozone decomposition part 36. The ozonizer 32 generates the ozone, and the ozone passage 31 supplies the ozone generated by the ozonizer 32 to the exhaust passage 15. The air pump 33 sends air to the ozone passage 31, and the ozone decomposition part 36 can enter a decomposition state for decomposing the ozone and a passage state for passing the ozone. The ozone decomposition part 36 comprises an ozone catalyst 36a for decomposing the ozone, a carrier 36b for supporting the ozone catalyst 36a, and a heater part 36c for heating the ozone catalyst 36a and the carrier 36b. The ozone decomposition part 36 enters the decomposition state from the passage state when the ozone catalyst 36a is heated by the heater part 36c.SELECTED DRAWING: Figure 1

Description

  The disclosure according to this specification relates to an ozone supply device and an ozone control device.

  As a technique for supplying ozone to an exhaust passage through which an exhaust gas from an internal combustion engine passes, for example, Patent Document 1 discloses an ozonizer that generates ozone, a blower pipe connected to the exhaust passage, and air to the blower pipe toward the exhaust passage. An ozone supply device including an air pump for feeding is disclosed. In this ozone supply device, when air is blown by the air pump when ozone is generated by the ozonizer, ozone is supplied from the blow pipe to the exhaust passage. On the other hand, when air is blown by the air pump even after ozone generation by the ozonizer is stopped, scavenging to expel ozone from the ozone supply device is performed. In this case, ozone flows into the exhaust passage from the air duct or ozonizer.

JP, 2016-65512, A

  However, in Patent Document 1, there is a concern that if ozone flowing into the exhaust passage from the ozone supply device by scavenging is not decomposed in the exhaust passage, ozone is released to the outside from the exhaust port of the exhaust passage.

  The main objective of this indication is to provide the ozone supply apparatus and ozone control apparatus which can suppress that ozone is discharge | released outside from an exhaust passage.

In order to achieve the above object, the disclosed first aspect is:
An ozone supply device for supplying ozone to an exhaust passage (15) through which exhaust discharged from an internal combustion engine (11) flows,
An ozone generator (32) for generating ozone;
An ozone passage (31) connected to the exhaust passage and supplying ozone generated by the ozone generator to the exhaust passage;
A blower (33) for sending wind to the ozone passage toward the exhaust passage;
A decomposition state in which ozone contained in the air flowing into the exhaust passage from the ozone passage in accordance with the air blowing by the air blowing unit is decomposed in the ozone passage, and a passage state in which the ozone contained in the air passes. , An ozonolysis part (36) that shifts to
It is an ozone supply device provided with

  According to the first aspect, since the ozone decomposing portion can be shifted between the passing state and the decomposing state, the ozone to the exhaust passage can be obtained while the air is flowing from the ozone passage to the exhaust passage. Can be permitted or regulated by the ozonolysis section. When the ozone decomposing unit is in a decomposing state, it can be regulated by the ozone decomposing unit that ozone flows into the exhaust passage when scavenging to expel ozone from the ozone supply device is performed. Therefore, even if ozone is difficult to be decomposed in the exhaust passage, it is possible to suppress the release of ozone from the exhaust passage to the outside.

The second aspect is
An ozone generator (32) for generating ozone;
An ozone passage (31) connected to an exhaust passage (15) through which the exhaust discharged from the internal combustion engine (11) flows, and supplying ozone generated by the ozone generator to the exhaust passage;
A blower (33) for sending wind to the ozone passage toward the exhaust passage;
A decomposition state in which ozone contained in the air flowing into the exhaust passage from the ozone passage in accordance with the air blowing by the air blowing unit is decomposed in the ozone passage, and a passage state in which the ozone contained in the air passes. , An ozonolysis part (36) that shifts to
An ozone control device (13) for controlling an ozone supply device having
The ozone control device includes a decomposition execution unit (S203, S204) that shifts the ozone decomposition unit from the passage state to the decomposition state.

  According to the second aspect, since the ozone decomposing unit is shifted from the passing state to the decomposing state, the ozone decomposing unit indicates that ozone flows into the exhaust passage when scavenging to expel ozone from the ozone supply device is performed. It can regulate. Therefore, the same effect as the first aspect can be obtained.

  In addition, the code | symbol in the bracket | parenthesis described in a claim and this clause only shows the correspondence with the specific means as described in embodiment mentioned later, and does not limit a technical range.

The figure which shows the structure of the combustion system in 1st Embodiment. The flowchart which shows the procedure of ozone control processing. The flowchart which shows the procedure of the ozone management process at the time of parking. The figure which shows the relationship between NOx catalyst temperature and the ozone concentration in the downstream of an exhaust gas purification device. The time chart which shows the implementation condition of decomposition | disassembly scavenging processing. The figure which shows the structure of the combustion system in 2nd Embodiment. The flowchart which shows the procedure of ozone supply processing.

  Hereinafter, a plurality of embodiments of the present disclosure will be described based on the drawings. In addition, the overlapping description may be abbreviate | omitted by attaching | subjecting the same code | symbol to the corresponding component in each embodiment. When only a part of the configuration is described in each embodiment, the configuration of the other examples described above can be applied to other portions of the configuration. Moreover, not only the combination of the configurations explicitly described in the description of each embodiment, but also the configuration of a plurality of embodiments can be partially combined even if they are not explicitly described, as long as there is no problem in the combination. And the combination where the structure described in several embodiment and the modification is not specified shall also be disclosed by the following description.

First Embodiment
A combustion system 10 shown in FIG. 1 includes an engine 11, an exhaust purification device 12, and an ECU 13. The combustion system 10 is mounted on a vehicle, and the vehicle runs using the output of the engine 11 as a drive source. The engine 11 as an internal combustion engine is a compression self-ignition type diesel engine, and light oil which is a hydrocarbon compound is used as a fuel used for combustion. An exhaust passage 15 through which exhaust exhausted from the engine 11 flows is connected to the engine 11.

The exhaust purification device 12 purifies the exhaust flowing through the exhaust passage 15. The exhaust purification device 12 has a NOx purification unit that purifies nitrogen oxide NOx contained in the exhaust. The NOx purification unit includes a NOx catalyst that stores and reduces NOx and a carrier that supports the NOx catalyst. Examples of the NOx catalyst include LNT (Lean NOx Traps) that are NOx storage and reduction catalysts. Be NOx includes nitrogen monoxide NO and nitrogen dioxide NO ₂ , and NO ₂ is more easily stored in the NOx catalyst than NO. The exhaust purification device 12 corresponds to an exhaust purification unit.

  The ECU (Engine Control Unit) 13 is a control device that controls the operation of the combustion system 10. The ECU 13 has a computer configured to include a processor 13a, a storage unit 13b, an input / output interface, and the like. Examples of the storage unit 13b include a RAM and a storage medium. Programs for controlling the operation of the engine 11 are stored in the storage unit 13b, and these programs are executed by the processor. The ECU 13 is electrically connected to actuators such as a throttle valve and a fuel injection valve, and controls the operation of these actuators by outputting a command signal.

  An exhaust pressure sensor 16, a temperature sensor 17, and an in-vehicle sensor 18 are electrically connected to the ECU 13, and these sensors 16 to 18 output respective detection signals to the ECU 13. The exhaust pressure sensor 16 is provided upstream of the exhaust purification device 12 in the exhaust passage 15, and detects the exhaust pressure between the engine 11 and the exhaust purification device 12. The temperature sensor 17 is provided in the exhaust gas purification device 12 and detects the temperature of the exhaust gas purification device 12. In the exhaust passage 15, the exhaust gas passes through the inside of the exhaust gas purification device 12, and the temperature of the exhaust gas purification device 12 is correlated with the exhaust gas temperature. In the present embodiment, the NOx catalyst temperature Ta, which is the temperature of the NOx catalyst, is used as a parameter indicating the temperature of the exhaust purification device 12. Note that the temperature of the carrier may be used as a parameter indicating the temperature of the exhaust purification device 12, and the temperature of the carrier can also be referred to as the bed temperature of the NOx purification unit. Further, the temperature sensor 17 may be an exhaust temperature sensor provided downstream of the exhaust purification device 12 in the exhaust passage 15.

  The in-vehicle sensor 18 has various sensors for acquiring the operating state of the engine 11. Sensors included in the in-vehicle sensor 18 include a rotation sensor that detects the rotation angle of the crankshaft, an in-cylinder pressure sensor that detects the pressure in the combustion chamber of the engine 11, an outside air temperature sensor that detects the outside air temperature, and the like. There is. The ECU 13 acquires the driving state and driving conditions based on the detection signal of the in-vehicle sensor 18.

The combustion system 10 includes an ozone supply device 30 that supplies ozone to the exhaust passage 15. The ozone supply device 30 is connected to the upstream side of the exhaust purification device 12 in the exhaust passage 15. When ozone is supplied from the ozone supply device 30 to the exhaust passage 15, NO present on the upstream side of the exhaust purification device 12 is oxidized by ozone and the ratio of NO ₂ increases, whereby the NOx purification of the exhaust purification device 12 is performed. This makes it easy to occlude NOx. That is, the NOx removal rate from the exhaust gas is easily improved.

  The ozone supply device 30 includes an ozone passage 31, an ozonizer 32, an air pump 33, a shut-off valve 35, and an ozone decomposition unit 36. The ozone passage 31 is connected to the exhaust passage 15 on the upstream side of both the exhaust purification device 12 and the exhaust pressure sensor 16. The ozonizer 32 is provided in the ozone passage 31 and generates ozone from the air taken into the ozone passage 31.

  The air pump 33 is an electric blower that drives the outside air, which is air, to the ozonizer 32 by being driven. The air pump 33 is provided upstream of the ozonizer 32 in the ozone passage 31. The air pump 33 can be shifted to a blowing state in which air is blown to the ozone passage 31 and a stopped state in which blowing is stopped. The air pump 33 shifts to a blowing state when a driving unit such as a motor is driven, and shifts to a stopped state when the driving unit stops driving. The ozone supply device 30 has an intake port 37 that takes in outside air from the outside on the upstream side of the ozonizer 32. The intake port 37 is provided at the upstream end of the ozone passage 31, and the air pump 33 is disposed between the ozonizer 32 and the intake port 37.

  The ozonizer 32 includes a plurality of electrodes, a housing unit that houses these electrodes, and a power feeding unit that supplies power to the electrodes. In the ozonizer 32, when a voltage is applied to the electrode along with the power supply from the power supply unit, ozone is generated by, for example, collision of electrons emitted from the electrode with oxygen molecules in the air. The ozone in the housing portion generated in this way is supplied from the ozonizer 32 to the exhaust passage 15 through the ozone passage 31 by blowing air from the air pump 33. In the present embodiment, when the power supply from the power supply unit to the electrode is stopped, the generation of ozone in the ozonizer 32 is stopped, and this state is referred to as a state in which the ozonizer 32 is stopped. The ozonizer 32 corresponds to an ozone generator.

  The ozone passage 31 has a supply port for supplying ozone to the exhaust passage 15, and this supply port is provided at the downstream end of the ozone passage 31. The shutoff valve 35 is provided between the ozonizer 32 and the supply port in the ozone passage 31, and can shut off the air flow on the downstream side of the ozonizer 32. When the shutoff valve 35 is in the closed state, the exhaust passage 15 is supplied from the ozone passage 31, and the exhaust gas flowing back from the exhaust passage 15 to the ozone passage 31 is restricted from reaching the ozonizer 32.

  In the ozone supply device 30, when air is supplied to the ozonizer 32 by the air pump 33, ozone is generated by the ozonizer 32, and ozone is further supplied from the ozone passage 31 to the exhaust passage 15 when the shut-off valve 35 is open. Supplied. Further, in the ozone supply device 30, the supply of ozone to the exhaust passage 15 is stopped if at least the shutoff valve 35 is closed.

  The ozone decomposition section 36 is provided between the ozonizer 32 and the shutoff valve 35 in the ozone passage 31. In this case, the ozone decomposing unit 36 is disposed at a position separated from the exhaust passage 15 to the outside, and the shut-off valve 35 is disposed at the separated portion. In addition, the ozone decomposition unit 36 is disposed at a position separated from a passage forming unit such as a pipe that forms the exhaust passage 15. As a result, the heat of the exhaust gas flowing through the exhaust passage 15 is hardly applied to the ozone decomposition unit 36.

The ozone decomposing unit 36 is capable of decomposing ozone contained in the air passing through the inside of the ozone decomposing unit 36. The ozone decomposition unit 36 includes an ozone catalyst 36a, a carrier 36b, and a heater unit 36c. The ozone catalyst 36a has a metal or metal oxide catalyst that decomposes ozone that has approached or contacted the ozone catalyst 36a. As this catalyst, silica (SiO ₂ ), alumina (Al ₂ O ₃ ), ferric oxide (Fe ₂ O ₃ ), manganese dioxide (MnO ₂ ), ferrous oxide (Fe ₂ O ₂ ), nickel oxide (NiO) and the like. The ability of the ozone catalyst 36a to decompose ozone is the ability of the ozone decomposition section 36 to decompose ozone, and this ability increases as the temperature of the ozone catalyst 36a increases. The carrier 36b is a base material formed in a honeycomb shape.

  The heater part 36c is a heating part that heats the ozone catalyst 36a and the carrier 36b, and is formed by a heating wire or the like attached to the carrier 36b. The heater unit 36c can be shifted between an ON state in which its own temperature rises and an OFF state in which its own temperature decreases. When the heater unit 36c is in the ON state, the entire ozone decomposition unit 36 is heated. The temperature rises. Even if the ozone contained in the air passing through the ozone decomposing unit 36 does not approach the ozone catalyst 36a, it is easily decomposed by the heat applied from the ozone decomposing unit 36.

  In the present embodiment, an ozone catalyst temperature Tb that is the temperature of the ozone catalyst 36a is used as a parameter indicating the temperature of the ozone decomposition unit 36. When the heater part 36c does not heat the ozone catalyst 36a or the carrier 36b, the ozone catalyst temperature Tb becomes the same as the outside air temperature because the heat of the exhaust gas is not easily applied to the ozone decomposition part 36 as described above. Cheap. In this case, the ozone decomposition capacity of the ozone catalyst 36a is sufficiently low. If ozone is contained in the air flowing through the ozone passage 31, the ozone passes through the ozone decomposition section 36 without being decomposed by the ozone catalyst 36a. It is easy to flow into the exhaust passage 15. Note that the temperature of the carrier 36 b or the temperature of the internal space of the ozone decomposition unit 36 may be used as a parameter indicating the temperature of the ozone decomposition unit 36. The temperature of the carrier can also be referred to as the bed temperature of the ozonolysis section 36.

  The shutoff valve 35 is a motorized open / close valve, and can be switched to an open state and a closed state. Regarding the shutoff valve 35, the closed state corresponds to a shutoff state in which the flow of air is shut off, and the open state corresponds to a released state in which air flows. The shut-off valve 35 is disposed between the ozone decomposition unit 36 and the exhaust passage 15 at a position as close as possible to the ozone decomposition unit 36. In FIG. 1, the shutoff valve 35 is illustrated as being separated from the ozone decomposition unit 36 to the downstream side, but the shutoff valve 35 of the present embodiment is not separated from the ozone decomposition unit 36 to the downstream side. The ozonolysis unit 36 is attached. For this reason, even if the shutoff valve 35 is shifted to the closed state when ozone is present in the ozone passage 31, ozone is present inside the ozone decomposing unit 36, but between the ozone decomposing unit 36 and the shutoff valve 35. Ozone is less likely to exist.

  The ECU 13 is electrically connected to the ozone supply device 30, and performs operation control of the ozone supply device 30. In this case, the ECU 13 is electrically connected to actuators such as an ozonizer 32, an air pump 33, a shut-off valve 35, and an ozone decomposition unit 36. The ECU 13 controls the operation of the ozone supply device 30 by controlling the operation of an actuator such as the ozonizer 32 according to the operating state of the engine 11 and the like. In this case, the ECU 13 corresponds to an ozone control device. In the ozonolysis unit 36, the heater unit 36c is an actuator controlled by the ECU 13.

  The ECU 13 performs an ozone control process for controlling the operation of the ozone supply device 30 so that ozone is not released to the outside from the ozone passage 31 or the exhaust passage 15. The ozone control process will be described with reference to FIGS.

  In FIG. 2, in step S <b> 101, it is determined whether ozone is supplied from the ozone supply device 30 to the exhaust passage 15. Here, for the ozone supply device 30, it is determined whether or not the ozonizer 32 is generating ozone, whether or not the air pump 33 is in the blowing state, and whether or not the shutoff valve 35 is in the open state. Make a decision. When both of these determinations are affirmed, it is determined that ozone is being supplied from the ozone supply device 30 to the exhaust passage 15, and the process proceeds to step S102.

  In step S102, it is determined whether or not the supply of ozone from the ozone supply device 30 to the exhaust passage 15 is stopped. Here, it is determined whether or not the engine 11 is stopped, and it is determined that the supply of ozone to the exhaust passage 15 is stopped when the engine 11 is stopped. Examples of the case where the engine 11 is stopped include a case where the shift range is switched to the parking range by the driver, and a case where a side brake is applied by the driver.

Even if the engine 11 is not stopped, it is determined whether or not to stop supplying ozone to the exhaust passage 15 according to the operating state of the engine 11. For example, it is determined whether or not NOx reduction processing for reducing NOx occluded by the NOx purification unit of the exhaust purification device 12 to N ₂ is performed. When NOx reduction processing is performed, ozone to the exhaust passage 15 is determined. To stop the supply of In the NOx reduction process, the combustion system 10 is controlled such that a reducing agent such as carbon monoxide CO or hydrocarbon HC that reduces NOx is supplied to the NOx purification unit. As this control, there is a control in which the injector injects more fuel in the engine 11 so that the exhaust gas contains CO and HC.

  When the supply of ozone to the exhaust passage 15 is stopped, the process proceeds to step S103, and the ozonizer 32 is stopped. Here, for the ozonizer 32, the power supply from the power supply unit to the electrode is stopped.

  In step S104, it is determined whether the engine 11 has stopped. Here, when the engine 11 is not stopped, the exhaust gas containing NOx is discharged from the engine 11 to the exhaust passage 15. In this case, ozone present in the exhaust passage 15 is reduced by being used for oxidation of NOx, and the possibility that ozone passes through the exhaust purification device 12 is reduced. On the other hand, when the engine 11 is stopped, exhaust containing NOx is not exhausted from the engine 11 to the exhaust passage 15, and therefore ozone present in the exhaust passage 15 is reduced because it is not used for oxidation of NOx. It becomes difficult. For this reason, compared with the case where the engine 11 has not stopped, possibility that ozone will pass the exhaust gas purification apparatus 12 will become high. Therefore, in step S104, it is determined whether or not ozone passing through the exhaust purification device 12 is likely to be generated by determining whether or not the engine 11 has stopped.

  If the engine 11 is stopped, ozone passing through the exhaust purification device 12 is easily generated, and the process proceeds to step S105, and it is determined whether the ignition switch as a power switch of the vehicle has shifted from the on state to the off state. If the ignition switch shifts to the off state, it is assumed that the vehicle is parked in a parking space or the like, and the process advances to step S106 to perform ozone management processing at the time of parking. On the other hand, when the ignition switch has not shifted to the off state, it is assumed that the engine 11 is temporarily stopped by the start of the idle stop, and the process proceeds to step S107 to perform ozone management processing at the idle stop. The process of step S107 is performed not only at idle stop but also when the engine 11 is temporarily stopped.

  The ozone management process during parking in step S106 will be described with reference to the flowchart of FIG.

  In FIG. 3, in step S201, it is determined whether or not the NOx catalyst temperature Ta has reached the NOx threshold value Tth1. Here, the NOx catalyst temperature Ta is acquired using the detection signal of the temperature sensor 17. Here, the ozone that has reached the exhaust purification device 12 is more easily decomposed as the NOx catalyst temperature Ta is higher. In other words, the higher the NOx catalyst temperature Ta, the more difficult the ozone passes through the exhaust purification device 12. In the present embodiment, for the NOx catalyst temperature Ta, the temperature at which most of the ozone that has reached the exhaust purification device 12 is decomposed is stored in the storage unit 13b as the NOx threshold value Tth1. The NOx threshold value Tth1 is a value determined in advance by a test or the like, and is set to 100 ° C., for example. Note that the NOx threshold value Tth1 corresponds to a reference value.

  As shown in FIG. 4, the ozone concentration on the downstream side of the exhaust purification device 12 decreases as the NOx catalyst temperature Ta increases. The NOx catalyst temperature Ta has a boundary between a temperature at which ozone is easily decomposed and a temperature at which ozone is difficult to decompose. In this embodiment, a temperature higher than the boundary is set as the NOx threshold Tth1.

  Returning to the description of FIG. 3, in this step S <b> 201, it is determined whether or not ozone is easily decomposed by the exhaust purification device 12 by determining whether or not the NOx catalyst temperature Ta has reached the NOx threshold value Tth <b> 1. When the NOx catalyst temperature Ta reaches the NOx threshold value Tth1, scavenging processing is performed in steps S210 to S212, assuming that ozone is easily decomposed by the exhaust purification device 12 and that ozone is not easily released to the outside from the exhaust port 15a.

  In this scavenging process, a scavenging start process is performed in step S210. Here, when the ozonizer 32 is stopped, it is considered that ozone remains in the ozone supply device 30 such as the ozonizer 32 and the ozone passage 31. In the present embodiment, scavenging air from the ozone supply device 30 such as the ozonizer 32 and the ozone passage 31 by blowing air from the air pump 33 after stopping the ozonizer 32 is referred to as scavenging. In the scavenging process of steps S210 to S212, the heater 36c of the ozonolysis unit 36 is in the OFF state, and the ozone contained in the air flowing through the ozone passage 31 passes through the ozonolysis unit 36 and is discharged to the exhaust passage 15. Flows in. In this embodiment, the process of releasing the ozone expelled from the ozone supply device 30 to the exhaust passage 15 without being decomposed by the ozone decomposition unit 36 is referred to as a passing scavenging process in this embodiment.

  In the ozone supply device 30, the ozonizer 32 is stopped in step S <b> 103, while the shutoff valve 35 is open and the air pump 33 is not stopped, so that the ozone supply device 30 performs scavenging. It is in a scavenging state. In this step S205, the ozonizer stop time Ea is measured as an elapsed time after the ozonizer 32 is stopped. In the present embodiment, as described above, since the scavenging of the ozone supply device 30 is continuously performed after the ozonizer 32 is stopped, the scavenging continuation time during which scavenging is continued is the same as the ozonizer stop time Ea.

  In step S211, it is determined whether the ozonizer stop time Ea has reached a predetermined stop threshold Eth1. Here, the determination process of step S211 is repeatedly executed until the ozonizer stop time Ea reaches the stop threshold Eth1. The stop threshold Eth1 is a time required for the amount of ozone remaining in the ozone supply device 30 after the ozonizer 32 is stopped to become substantially zero by scavenging, and is a value set by a test or the like. In step S211, it is determined whether or not scavenging is terminated by determining whether or not the ozonizer stop time Ea has reached the stop threshold Eth1.

  When the ozonizer stop time Ea reaches the stop threshold Eth1, the scavenging is terminated, and the process proceeds to step S212 to perform the scavenging stop processing. In this process, after the shutoff valve 35 is shifted to the closed state, the air pump 33 is shifted to the stopped state. Thus, the shutoff valve 35 prevents the exhaust gas from flowing back from the exhaust passage 15 to the ozone passage 31 and reaching the ozonizer 32. In the passing scavenging process of steps S210 to S212, the air pump 33 continues blowing air until scavenging of the ozone supply device 30 is completed even after the vehicle is parked.

  When the passing scavenging process is performed in steps S210 to S212, the ozone expelled to the exhaust passage 15 due to scavenging due to the NOx catalyst temperature Ta being higher than the NOx threshold Tth1 is sent to the exhaust purification device 12. Most of them are decomposed by reaching. For this reason, it is difficult for ozone that has passed through the exhaust gas purification device 12 to be released to the outside from the exhaust port 15a.

  If the NOx catalyst temperature Ta is lower than the NOx threshold Tth1 in step S201, a decomposition scavenging process for decomposing ozone expelled from the ozone supply device 30 in the ozone decomposition unit 36 is performed as a scavenging process in steps S202 to S209. .

  In the decomposition scavenging process, in step S202, the shutoff valve 35 is shifted from the open state to the closed state while the air pump 33 continues blowing air. In this case, the shutoff valve 35 restricts ozone from flowing into the exhaust passage 15 from the ozone passage 31. In addition, since air is blown by the air pump 33, residual ozone remaining in the ozone passage 31 is likely to be pressed against the shutoff valve 35 by the wind sent by the air pump 33. Therefore, the residual ozone is less likely to be released from the intake port 37 of the ozone passage 31 to the outside.

  In step S203, the heater unit 36c is shifted to the on state. As a result, the heating of the carrier 36b and the ozone catalyst 36a by the heater 36c is started.

  In step S204, it is determined whether the ozone catalyst temperature Tb has reached the ozone threshold Tth2. Here, the outside air temperature is acquired based on the detection signal of the in-vehicle sensor 18, and the elapsed time after the heater 36c is switched to the on state is measured as the heating time. Then, the temperature of the ozone catalyst temperature Tb is estimated and acquired using the outside air temperature and the heating time. Here, the ozone delivered to the ozone decomposition unit 36 is more easily decomposed as the ozone catalyst temperature Tb is higher. In the present embodiment, for the ozone catalyst temperature Tb, the temperature at which most of the ozone that has reached the ozone decomposing unit 36 is decomposed is stored in the storage unit 13b as the ozone threshold Tth2. The ozone threshold value Tth2 is a value determined in advance by a test or the like, and is set to 100 ° C., for example.

  In this step S204, it is determined whether or not the ozonolysis capability of the ozonolysis unit 36 has become sufficiently high by determining whether or not the ozone catalyst temperature Tb has reached the ozone threshold Tth2, or the heater unit 36c. It is determined whether or not the heating of the ozonolysis section 36 is to be terminated. Then, the determination process of step S204 is repeatedly executed until the ozone catalyst temperature Tb reaches the ozone threshold Tth2. If the ozone catalyst temperature Tb has reached the ozone threshold Tth2, it is determined that the ozonolysis ability of the ozonolysis unit 36 has become sufficiently high, and the process proceeds to step S205. As for the ozone decomposition unit 36, the state where the ozone catalyst temperature Tb has reached the ozone threshold value Tth2 corresponds to a decomposition state where ozone is decomposed, and the state where the ozone catalyst temperature Tb has not reached the ozone threshold value Tth2 allows ozone to pass through. Corresponds to the passing state.

  In step S205, the shutoff valve 35 is shifted to the open state. Here, since air is blown by the air pump 33, the air confined in the ozone passage 31 by the shutoff valve 35 passes through the ozone decomposition section 36 and is expelled toward the exhaust passage 15. In this case, ozone contained in the air passing through the ozonolysis unit 36 is easily decomposed by the ozone catalyst 36 a due to the ozonolysis ability of the ozonolysis unit 36 being sufficiently high. For this reason, it is difficult for ozone to flow into the exhaust passage 15 through the ozone decomposition part 36.

  In step S206, it is determined whether the valve opening time Eb which is the elapsed time after the shutoff valve 35 transfers to an open state has reached the predetermined valve opening threshold value Eth2. Here, the determination process of step S206 is repeatedly executed until the valve opening time Eb reaches the valve opening threshold Eth2. In the present embodiment, since the scavenging of the ozone supply device 30 is started when the shutoff valve 35 shifts to the open state, the time during which scavenging is performed becomes the same as the valve opening time Eb. The valve opening threshold value Eth2 is a time required for the amount of ozone remaining in the ozone supply device 30 such as the ozone passage 31 to become almost zero after the shutoff valve 35 is opened, and is set by a test or the like It is a value. The valve opening threshold Eth2 is set to the same value as the stop threshold Eth1, for example. In the present step S206, it is judged whether or not the scavenging is ended by judging whether the valve opening time Eb has reached the valve opening threshold value Eth2.

  When the valve opening time Eb reaches the valve opening threshold Eth2, scavenging is terminated, and scavenging stop processing is performed in steps S210 to S212 as in step S212. In this scavenging stop process, the shutoff valve 35 is shifted to the closed state in step S207, the air pump 33 is shifted to the stopped state in step S208, and the heater portion 36c is shifted to the off state in step S209. In the decomposition and scavenging process in steps S202 to S209, the air pump 33 continues to blow air until the scavenging of the ozone supply device 30 ends even after the vehicle is parked.

  Returning to the description of FIG. 2, if it is determined in step S105 that the ignition switch has not shifted to the OFF state, the process proceeds to step S107 to perform ozone management processing during idle stop. In this process, similarly to the ozone management process at the time of parking, it is determined whether or not ozone is easily decomposed by the exhaust purification device 12 using the NOx catalyst temperature Ta, and if it is easily decomposed, steps S210 to S212 are performed. Similarly, a passing scavenging process is performed. On the other hand, when ozone is difficult to be decomposed by the exhaust purification device 12, the shutoff valve 35 is shifted to the closed state and the air pump 33 continues to blow. As described above, ozone is suppressed from being released from the exhaust port 15a and the intake port 37 to the outside regardless of whether the exhaust purification device 12 is easily decomposed or is not easily decomposed.

  If it is determined in step S104 that the engine 11 is not stopped, the process proceeds to step S108, and ozone management processing during engine operation is performed. In this process, using the detection signal of the exhaust pressure sensor 16, the pressure at the upstream side of the exhaust purification device 12 in the exhaust passage 15 is acquired as the exhaust pressure. Then, it is determined whether or not the exhaust pressure becomes so large that the exhaust gas flows backward from the exhaust passage 15 to the ozone passage 31. Here, the determination pressure is set based on the wind pressure in the ozone passage 31 by the air blow of the air pump 33, it is determined whether or not the exhaust pressure is larger than the determination pressure, and when the exhaust pressure is larger than the determination pressure, the ozone passage 31 is determined. It is determined that the exhaust pressure is so large that the exhaust flows backward.

  If the exhaust pressure is higher than the determination pressure, the shutoff valve 35 is switched to the closed state, and the air pump 33 continues to blow air. In this case, the ozone is pushed toward the intake port 37 by the exhaust gas flowing backward in the ozone passage 31, whereby the ozone is prevented from being released from the intake port 37 to the outside. In addition, not only ozone but also exhaust gas is prevented from being discharged from the intake port 37 to the outside. On the other hand, when the exhaust pressure is not larger than the determination pressure, the passing scavenging process is performed. In this case, even if ozone flows from the ozone passage 31 into the exhaust passage 15, this ozone is used in the exhaust passage 15 for oxidation of NOx in the exhaust gas and consumed. Therefore, it is difficult for ozone to be released to the outside from the exhaust port 15a.

  The ECU 13 has a function of executing each step of the ozone control process. The function for executing the process of step S202 corresponds to the interruption execution unit, the function for executing the processes of steps S203 and S204 constitutes a disassembly execution unit, and the function of executing the process of step S205 corresponds to the release execution unit.

  Next, an embodiment of the decomposition and scavenging process by the ozone control process will be described with reference to the time chart of FIG.

  In FIG. 5, the NOx catalyst temperature Ta is lower than the NOx threshold Tth1 at a timing t1 at which the ignition switch is turned off after the ozonizer 32 is stopped and the engine 11 is stopped. In this case, ozone is difficult to be decomposed in the exhaust gas purification device 12, and the decomposition scavenging process is started, whereby the ozone catalyst temperature Tb starts to rise. Specifically, in a state where the air pump 33 continues blowing, the shutoff valve 35 is shifted to the closed state, and the heater portion 36c is shifted to the on state. Then, at the timing t2 when the ozone catalyst temperature Tb reaches the ozone threshold Tth2, scavenging of the ozone supply device 30 is started by moving the shut-off valve 35 to the open state. In this case, since the residual ozone in the ozone passage 31 is decomposed by the ozone decomposition unit 36, the flow of ozone from the ozone passage 31 into the exhaust passage 15 is suppressed, and as a result, the ozone is released to the outside from the exhaust port 15a. Is suppressed.

  At timing t3 when the valve opening threshold value Eth2 has elapsed from timing t2, the shutoff valve 35 is shifted to the closed state and the heater portion 36c is shifted to the off state, whereby scavenging of the ozone supply device 30 is ended. After the heater part 36c shifts to the off state, the ozone catalyst temperature Tb gradually decreases.

  According to the present embodiment described so far, the ozone decomposing unit 36 can shift between a decomposition state in which the ozone catalyst temperature Tb has reached the ozone threshold value Tth2 and a passing state in which the ozone catalyst temperature Tb has not reached the ozone threshold value Tth2. It has become. For this reason, in the state where air is supplied from the ozone passage 31 to the exhaust passage 15, the ozone decomposition section 36 can permit or restrict the flow of ozone into the exhaust passage 15. That is, the passing scavenging process and the decomposition scavenging process can be used intentionally. Therefore, even if ozone is difficult to be decomposed in the exhaust passage, ozone can be suppressed from being released to the outside from the exhaust port 15a of the exhaust passage 15 when the ozone catalyst temperature Tb reaches the ozone threshold Tth2. .

  According to the present embodiment, since the ozonolysis unit 36 includes the heater 36c, the heat of the heater 36c can forcibly increase the ozone catalyst temperature Tb to the ozone threshold Tth2. Here, as a configuration for restricting the release of ozone from the exhaust port 15a to the outside, in addition to the present embodiment, the exhaust gas purification device 12 has a heater portion, and the heater portion heats the NOx purification portion and the like. Thus, a configuration in which the NOx catalyst temperature Ta is forcibly increased is conceivable. However, in this configuration, the heater portion that can heat the exhaust gas purification device 12 provided in the exhaust passage 15 through which the exhaust gas flows may be enlarged, and power consumption may also be increased. On the other hand, according to the present embodiment, the ozone decomposing unit 36 provided in the ozone passage 31 that only needs to be able to supply ozone does not need to be enlarged like the exhaust gas purification device 12. Thus, since the heater part 36c should just heat the ozone decomposition | disassembly part 36 instead of the exhaust gas purification apparatus 12, size reduction and power saving can be achieved about this heater part 36c.

  According to the present embodiment, since the ozone decomposition unit 36 includes the ozone catalyst 36a, ozone can be decomposed by the ozone decomposition ability of the ozone catalyst 36a in addition to the heat generated from the heater unit 36c. In other words, the amount of ozone decomposed by the ozone catalyst 36a can be increased by increasing the ozone decomposing ability of the ozone catalyst 36a by the heat of the heater 36c.

  According to the present embodiment, since the ozonolysis unit 36 is disposed at a position separated from the exhaust passage 15 in the ozone passage 31, the heat of the exhaust flowing through the exhaust passage 15 is less likely to be applied to the ozonolysis unit 36 . Therefore, when ozone is supplied from the ozone supply device 30 to the exhaust passage 15, the ozone catalyst temperature Tb is increased by the heat of the exhaust and ozone is unintentionally decomposed in the ozone decomposition unit 36. It can be suppressed.

  According to the present embodiment, since the shutoff valve 35 is provided between the ozone decomposing portion 36 and the exhaust passage 15 in the ozone passage 31, the exhaust gas flows backward through the ozone passage 31 from the exhaust passage 15. Can be regulated. For this reason, it can suppress that the ozone catalyst 36a etc. are polluted by exhaust_gas | exhaustion, and the ozone decomposition | disassembly capability of the ozone decomposition | disassembly part 36 falls.

  According to this embodiment, since the ozone decomposing unit 36 shifts from the passing state to the decomposing state by causing the heater unit 36 c to be turned on by the ECU 13, the execution of ozone decomposition by the ozone decomposing unit 36 is managed by the ECU 13. Can. For this reason, it can suppress that ozone is decomposed | disassembled unintentionally by the ozone decomposition part 36. FIG.

  According to the present embodiment, when the NOx catalyst temperature Ta becomes lower than the NOx threshold value Tth1, the ECU 13 causes the ozone decomposition unit 36 to shift to the decomposition state. In this case, the ozone decomposing unit 36 regulates the flow of ozone from the ozone passage 31 into the exhaust passage 15 to create a situation in which ozone does not exist in the exhaust passage 15. That can be prevented from being released into the water.

  According to the present embodiment, the ozone catalyst temperature Tb can be raised to the ozone threshold value Tth2 by causing the ECU 13 to shift the heater 36c to the on state to raise the temperature of the heater 36c. As described above, the ECU 13 can properly manage whether the ozonolysis unit 36 is in the decomposition state or the passage state.

  According to the present embodiment, when the ozone catalyst temperature Tb is raised to the ozone threshold value Tth2 by heating the heater portion 36c, the ECU 13 causes the shutoff valve 35 to shift to the closed state. Therefore, the shutoff valve 35 can regulate that ozone passes through the ozone decomposition section 36 and flows into the exhaust passage 15 from the start of heating by the heater section 36c until the ozone catalyst temperature Tb reaches the ozone threshold value Tth2. Therefore, even if the ozone decomposing unit 36 is configured not to immediately shift from the passing state to the decomposing state, it is possible to suppress the release of ozone from the exhaust port 15a by the shutoff valve 35.

  According to the present embodiment, when the ozone catalyst temperature Tb reaches the ozone threshold value Tth2, the ECU 13 shifts the shutoff valve 35 from the closed state to the open state. In this case, since ozone contained in the air passing through the ozone decomposing unit 36 is decomposed by the ozone decomposing unit 36, scavenging of the ozone supply device 30 is performed in a state where ozone is prevented from flowing into the exhaust passage 15. Can do. Thus, it is possible to suppress both the occurrence of corrosion of the ozone supply device 30 due to the ozone remaining inside the ozone supply device 30, and the release of ozone from the exhaust port 15a to the outside.

  According to this embodiment, when the engine 11 is stopped, the ECU 13 shifts the ozone decomposition unit 36 to the decomposition state. In this case, even if scavenging of the ozone supply device 30 is performed, since the ozone decomposing unit 36 regulates that ozone flows from the ozone passage 31 into the exhaust passage 15, NOx is discharged in the exhaust passage 15 when the engine 11 is stopped. It is possible to suppress the excess of ozone. For this reason, it can suppress that the ozone which became excess in the exhaust passage 15 is discharge | released outside from the exhaust port 15a.

  According to the present embodiment, when the ozonizer 32 is stopped, the ECU 13 causes the ozone decomposition unit 36 to shift to the decomposition state. In this case, it is possible to avoid that the ozone generated by the ozonizer 32 is decomposed by the ozonizer 36 and not supplied to the exhaust passage 15 although ozone is required in the exhaust passage 15. .

Second Embodiment
In the second embodiment, the ozone supply device 30 includes a temperature detection unit that detects the temperature of the ozone decomposition unit 36. In the present embodiment, the difference from the first embodiment will be mainly described.

  As shown in FIG. 6, a decomposition temperature sensor 41 as a temperature detection unit is attached to the ozone decomposition unit 36. The decomposition temperature sensor 41 detects the temperature of the carrier 36b and the ozone catalyst 36a by outputting a detection signal corresponding to the internal temperature of the ozone decomposition unit 36. The decomposition temperature sensor 41 is electrically connected to the ECU 13, and the ECU 13 acquires the ozone catalyst temperature Tb using the detection signal of the decomposition temperature sensor 41.

  The combustion system 10 of the present embodiment includes an exhaust temperature sensor 42 that detects the temperature of exhaust flowing through the exhaust passage 15 as the exhaust temperature. The exhaust temperature sensor 42 is provided downstream of the exhaust gas purification device 12 in the exhaust passage 15 and detects the exhaust gas flowing out of the exhaust gas purification device 12 as a detection target. In the exhaust passage 15, the exhaust passes through the inside of the exhaust purification device 12, and the temperature of the exhaust purification device 12 correlates with the exhaust temperature. In the present embodiment, when the catalyst temperature Tea that is the temperature of the NOx catalyst is used as the parameter indicating the temperature of the exhaust gas purification device 12, the NOx catalyst temperature Ta is acquired using the detection signal of the exhaust temperature sensor 42. In the present embodiment, the combustion system 10 does not have the temperature sensor 17, but the combustion system 10 may have both the temperature sensor 17 and the exhaust temperature sensor 42.

  In the present embodiment, in the ozone control process executed by the ECU 13, the decomposition and scavenging process is also performed in the ozone management process during idle stop. Specifically, in the ozone management process at the time of idling stop in step S107 shown in FIG. 2, when the NOx catalyst temperature Ta reaches the NOx threshold Tth1, the decomposition scavenging process in steps S202 to S209 shown in FIG. 3 is performed. . However, if restart of the engine 11 is performed at the timing before the ozone catalyst temperature Tb reaches the ozone threshold Tth2 or at the timing before the valve opening time Eb reaches the valve opening threshold Eth2, the decomposition scavenging process is performed halfway Stop at Then, a process of supplying ozone from the ozone supply device 30 to the exhaust passage 15, a process of shifting the shutoff valve 35 to a closed state so that the exhaust gas does not flow backward from the exhaust passage 15 to the ozone passage 31 are performed.

  As described above, in the configuration in which decomposition scavenging processing is performed even when the vehicle is parked, there is a concern that the ozone catalyst temperature Tb has reached the ozone threshold Tth2 when ozone is supplied from the ozone supply device 30 to the exhaust passage 15. Ru. In this case, ozone generated by the ozonizer 32 is decomposed by the ozone decomposition unit 36, and ozone cannot be supplied from the ozone supply device 30 to the exhaust passage 15.

  Therefore, the ECU 13 of the present embodiment performs an ozone supply process of supplying ozone to the exhaust passage 15 after performing a process of cooling the ozone decomposition unit 36. Here, the ozone supply process will be described with reference to the flowchart of FIG. The ozone supply process is executed before step S101 shown in FIG. 2 in the ozone control process.

  In FIG. 7, in step S <b> 301, it is determined whether or not ozone is supplied from the ozone supply device 30 to the exhaust passage 15. Here, the operating state of the engine 11 is acquired based on the detection signal of the in-vehicle sensor 18, and it is determined based on the operating state whether or not to supply ozone.

  In the case of supplying ozone, the process proceeds to step S302, and the decomposition temperature sensor 41 uses the detection signal to acquire the ozone catalyst temperature Tb. In step S303, it is determined whether or not the ozone catalyst temperature Tb has reached the ozone threshold Tth2. If the ozone catalyst temperature Tb has reached the ozone threshold value Tth2, the ozone decomposing unit 36 decomposes ozone even if ozone is generated by the ozonizer 32, and the process proceeds to step S304 to perform a cooling process. In this cooling process, air blowing by the air pump 33 is started in a state where the shutoff valve 35 is in a closed state, and then the shutoff valve 35 is shifted to an open state. In this case, after restricting the exhaust gas from flowing backward in the ozone passage 31 by the air pump 33, the air sent by the air pump 33 passes through the ozone decomposing unit 36, whereby the ozone decomposing unit 36 is cooled. As a result, the ozone catalyst temperature Tb decreases.

  In step S305, it is determined whether the ozone catalyst temperature Tb has become lower than the ozone threshold Tth2. Here, the determination process of step S305 is repeatedly performed until the ozone catalyst temperature Tb becomes lower than the ozone threshold value Tth2.

  When the ozone catalyst temperature Tb becomes lower than the ozone threshold value Tth2, the process proceeds to step S306, and ozone supply processing for supplying ozone from the ozone supply device 30 to the exhaust passage 15 is performed. Here, due to the fact that the shutoff valve 35 is in the open state and the air pump 33 is in the blowing state, ozone generation to the exhaust passage 15 is started by simply starting ozone generation by the ozonizer 32.

  If it is determined in step S303 that the ozone catalyst temperature Tb has not reached the ozone threshold value Tth2, the ozone decomposing unit 36 determines that ozone is not easily decomposed, and proceeds to step S306 without performing the cooling process. I do. Here, in the situation where the shut-off valve 35 is in the closed state, air blowing by the air pump 33 is started, and then the shut-off valve 35 is shifted to the open state and ozone generation by the ozonizer 32 is started. Thereby, ozone supply from the ozone supply device 30 to the exhaust passage 15 is started.

  According to the present embodiment, since the cooling process for cooling the ozonolysis unit 36 is performed, the ozone catalyst temperature Tb can be positively reduced. Therefore, when the ozone catalyst temperature Tb reaches the ozone threshold Tth2, it is possible to shorten the time required for the ozone catalyst temperature Tb to drop to a temperature lower than the ozone threshold Tth2. Therefore, even if the ozone catalyst temperature Tb has reached the ozone threshold Tth2 when there is a request for ozone supply to the exhaust passage 15, the delay time until starting the ozone supply to the exhaust passage 15 is shortened as much as possible. be able to.

(Other embodiments)
Although a plurality of embodiments of the present disclosure have been described above, the present disclosure is not construed as being limited to those embodiments, and various embodiments and combinations can be made without departing from the scope of the present disclosure. It can apply.

  As a first modification, when heating of the ozone decomposition unit 36 by the heater unit 36c is started, the heater unit 36c is shifted to the on state in a state in which the shutoff valve 35 is open or in a state in which the air pump 33 is stopped. It is also good. In addition, the shutoff valve 35 may be kept open from the start of heating by the heater 36c until the ozone catalyst temperature Tb reaches the ozone threshold Tth2. However, in this case, there is a concern that the residual ozone in the ozone supply device 30 may become zero at a timing before the ozone catalyst temperature Tb reaches the ozone threshold value Tth2, and therefore air blowing by the air pump 33 is stopped. Is preferred.

  As a second modification, the ozonolysis unit 36 may be provided downstream of the shutoff valve 35 in the ozone passage 31. Even in this case, the shutoff valve 35 can regulate that ozone is supplied to the exhaust passage 15 and that the exhaust gas flows back through the ozone passage 31 and reaches the ozonizer 32.

  As a third modification, the ozonolysis unit 36 may be provided at a position to which the heat of the exhaust flowing through the exhaust passage 15 is easily applied. For example, the ozone decomposition section 36 is provided at a position where the ozone passage 31 enters the exhaust passage 15. Even in this configuration, by providing a heat insulating material or the like on the outer peripheral surface of the ozone decomposing unit 36, it is possible to prevent the ozone catalyst temperature Tb from unintentionally rising due to the heat of the exhaust gas.

  As a fourth modification, the ozone decomposing unit 36 does not have to have the ozone catalyst 36a while having the heater unit 36c. Also in this case, the ozone contained in the air passing through the ozonolysis unit 36 can be decomposed by the heat generated from the heater 36 c. For example, the ozone decomposition unit 36 includes a filter member that allows air to pass through, and the filter member is heated by the heater unit 36c. Even in this configuration, when the heater portion 36c shifts to the ON state, the temperature of the filter member rises and ozone is easily decomposed. In this case, by setting the parameter indicating the temperature of the ozone decomposition unit 36 to the filter temperature that is the temperature of the filter member, heating by the heater unit 36c can be started based on the filter temperature. For example, when the filter temperature reaches the ozone threshold Tth2, the ozonolysis unit 36 shifts to the decomposition state, and when the filter temperature becomes lower than the ozone threshold Tth2, the ozonolysis unit 36 shifts to the passing state.

  As a fifth modification, the ozonolysis unit 36 may have the ozone catalyst 36 a but may not have the heater unit 36 c. For example, the ozonolysis portion 36 has a bifurcated first passage portion and a second passage portion, and the ozonolysis portion 36 is provided in the first passage portion of the first passage portion and the second passage portion. Configure In this configuration, the ozone decomposing unit 36 has a switching valve that can be switched between the first state and the second state. When the switching valve is in the first state, air does not flow in the first passage while it does not flow in the second passage, and when the switching valve is in the second state, air does not flow in the first passage. Flows through the second passage. That is, the air flowing through the ozone passage 31 passes through the ozone decomposition unit 36 when the switching valve is in the first state, and does not pass through the ozone decomposition unit 36 when the switching valve is in the second state. The switching valve may be provided at a branch portion between the first passage portion and the second passage portion, or may be provided at each of the first passage portion and the second passage portion.

  In the present modification, it is preferable that ozone is sufficiently decomposed by the ozone catalyst 36a even if the ozone catalyst temperature Tb is a relatively low value such as the same as the outside air temperature. Therefore, the switching valve is switched to the second state in the passing scavenging process. In this case, since the air flowing through the ozone passage 31 does not pass through the ozone decomposing unit 36, ozone contained in the air flows into the exhaust passage 15. On the other hand, in the decomposition and scavenging process, the switching valve is switched to the first state. In this case, since the air flowing through the ozone passage 31 passes through the ozone decomposing portion 36, ozone contained in this air is decomposed by the ozone catalyst 36 a of the ozone decomposing portion 36, so that it is difficult for ozone to flow into the exhaust passage 15. . As described above, when the switching valve is in the first state, the ozone decomposition unit 36 suppresses that ozone is released to the outside from the exhaust port 15a.

  In this configuration, the ozone decomposition unit 36 is in the decomposition state when the switching valve is in the first state, and the ozone decomposition unit 36 is in the passage state when the switching valve is in the second state. In this case, the time required to shift the ozonolysis unit 36 from the passing state to the decomposition state is shorter than in the configuration in which the ozonolysis unit 36 is heated by the heater unit 36c as in the first embodiment. Therefore, the decomposition scavenging process can be performed promptly after the ozonizer 32 is stopped.

  As a sixth modification, the parameter for determining whether to shift the ozonolysis unit 36 to the decomposition state may be the exhaust gas temperature instead of the temperature of the exhaust gas purification device 12 such as the NOx catalyst temperature Ta.

  As a seventh modification, when the NOx catalyst temperature Ta is lower than the NOx threshold value Tth1, instead of the decomposition scavenging process in which ozone does not easily flow into the exhaust passage 15, the passage scavenging process in which ozone easily flows into may be performed. For example, when the engine 11 is in operation, even if the NOx catalyst temperature Ta is lower than the NOx threshold Tth1, not the decomposition scavenging process but the passage scavenging process is performed. Further, when the amount of NOx present in the exhaust passage 15 is larger than the predetermined judgment value, the passing scavenging process is performed instead of the decomposition scavenging process even if the NOx catalyst temperature Ta is lower than the NOx threshold Tth1. In any configuration, the ozone expelled from the ozone supply device 30 to the exhaust passage 15 is easily consumed by the oxidation of NOx. Therefore, even if the passing scavenging process is performed instead of the decomposition scavenging process, the ozone is released to the outside from the exhaust port 15a. It is difficult to occur.

  As a modification 8, the exhaust gas purification device 12 may have a collection portion for collecting particulate matter PM (Particulate Matter) contained in the exhaust gas. Examples of the collection unit include DPF (Diesel Particulate Filter) which is a particulate collection device. In the collection unit, the collected PM is burned and removed by the heat of the exhaust gas or the like to regenerate the PM collection capacity. In this case, the combustion of PM is promoted by applying the ozone supplied from the ozone supply device 30 to the collection unit, and the ozone is consumed along with the combustion of PM. For this reason, the smaller the amount of PM collected at the collection section, the less ozone is used for PM combustion.

  Therefore, the ECU 13 acquires the PM collection amount of the collection unit, and determines whether the PM collection amount is larger than a predetermined determination value. Then, when the amount of collected PM is larger than the determination value, passing scavenging processing is performed in which ozone easily flows into the exhaust passage 15, and when the amount of collected PM is not larger than the determination value Perform scavenging treatment. When the amount of collected PM is larger than the determination value, ozone is consumed by PM of the collection unit, whereby the release of ozone from the exhaust port 15a to the outside is suppressed. On the other hand, when the amount of PM trapped is not larger than the determination value, ozone is decomposed by the ozone decomposing unit 36, so that release of ozone from the exhaust port 15a to the outside is suppressed. When the PM trapping amount is larger than the determination value, the passing scavenging process may be performed instead of the decomposition scavenging process even if the NOx catalyst temperature Ta is lower than the NOx threshold Tth1.

  As a modification 9, in addition to the downstream side of the ozonizer 32, in the ozone supply device 30, a shutoff valve may be provided also on the upstream side. When the shutoff valve 35 provided on the downstream side of the ozonizer 32 is referred to as a downstream valve, and the shutoff valve provided on the upstream side of the ozonizer 32 is referred to as an upstream valve, the ozonizer 32 and ozone are interposed between the upstream valve and the downstream valve. A disassembly unit 36 is provided. In this configuration, ozone can be trapped between the upstream valve and the downstream valve by closing both the upstream valve and the downstream valve. For example, ozone is trapped between the upstream valve and the downstream valve in a period from when the heater 36c is turned on to when the ozonolysis unit 36 is decomposed, ozone is discharged from the exhaust port 15a. And the release from the intake 37 can be suppressed.

  As a modification 10, the configuration that exerts the function as an ozone control device may be various arithmetic devices mounted in a vehicle instead of the ECU 13, and a plurality of arithmetic devices cooperate with each other to function as a control device. It may be demonstrated. In addition, various programs may be stored in a non-transitional tangible storage medium such as a flash memory or a hard disk provided in each arithmetic device.

  11: Engine as an internal combustion engine, 12: Exhaust purification device as an exhaust purification unit, 13: ECU as an ozone control device, 15: exhaust passage, 31: ozone passage, 32: ozonizer as an ozone generation unit, 33: ventilation Air pump as part 35: Shut-off valve, 36: Ozone decomposition part, 36a: Ozone catalyst, 36c: Heater part, Tth1: NOx threshold as a reference value, Ta: NOx catalyst temperature, S202: Blocking execution part, S203: Decomposition Execution unit, S204... Disassembly execution unit, S205.

Claims (12)

An ozone supply device for supplying ozone to an exhaust passage (15) through which exhaust discharged from an internal combustion engine (11) flows,
An ozone generator (32) for generating ozone;
An ozone passage (31) connected to the exhaust passage and supplying ozone generated by the ozone generator to the exhaust passage;
A blower section (33) for sending wind toward the ozone passage toward the exhaust passage;
In the ozone passage, provided in the downstream side of the ozone generation section, a decomposition state for decomposing ozone contained in the air flowing from the ozone passage into the exhaust passage in accordance with the blowing by the blowing section, and ozone contained in the air A state of passage through which ozone is passed, and an ozonolysis part (36) that shifts to
An ozone supply device equipped with The ozone decomposition unit is
It has a heater part (36c) which makes the ozone decomposition part shift to the decomposition state by raising temperature, and makes the ozone decomposition part move to the passage state by lowering temperature. Ozone supply device. The ozone decomposition unit is
An ozone catalyst (36a) that is provided in the ozone passage and has a high ability to decompose ozone as the temperature of the heater increases.
The ozone supply device according to claim 2, wherein the ozone catalyst shifts to the decomposition state when the temperature rises and the ozone catalyst shifts to the passage state when the temperature of the ozone catalyst decreases.   The ozone supply device according to any one of claims 1 to 3, wherein the ozone decomposition unit is provided at a position separated from the exhaust passage in the ozone passage.   The ozone supply device according to any one of claims 1 to 4, further comprising a shutoff valve (35) for shutting off an air flow between the ozone decomposition section and the exhaust passage in the ozone passage. An ozone generator (32) for generating ozone;
An ozone passage (31) connected to an exhaust passage (15) through which exhaust gas discharged from the internal combustion engine (11) flows, and supplying ozone generated by the ozone generator to the exhaust passage;
A blower section (33) for sending wind toward the ozone passage toward the exhaust passage;
In the ozone passage, provided in the downstream side of the ozone generation section, a decomposition state for decomposing ozone contained in the air flowing from the ozone passage into the exhaust passage in accordance with the blowing by the blowing section, and ozone contained in the air A state of passage through which ozone is passed, and an ozonolysis part (36) that shifts to
An ozone control device (13) for controlling an ozone supply device having
An ozone control device comprising a decomposition execution unit (S203, S204) that shifts the ozone decomposition unit from the passage state to the decomposition state. The decomposition execution unit
When the temperature (Ta) of the exhaust gas purification unit (12) provided in the exhaust passage and purifies the exhaust gas becomes lower than a predetermined reference value (Tth1), the ozone decomposition unit is moved from the passage state to the decomposition state. The ozone control device according to claim 6, which is shifted to the state. The decomposition execution unit
The ozone control device according to claim 6 or 7, wherein the ozone decomposing unit is shifted from the passing state to the decomposing state by increasing the temperature of the heater unit (36c) included in the ozone decomposing unit.   When the decomposition execution unit raises the temperature of the heater unit to shift the ozonolysis unit from the passing state to the decomposition state, the decomposition execution unit is provided between the ozonolysis unit and the exhaust passage in the ozone passage. The ozone control device according to claim 8, further comprising: a shutoff execution unit (S202) for shifting the shutoff valve (35) to a shutoff state that shuts off the flow of air.   A release execution unit that shifts the shut-off valve to a release state that releases the shut-off of the air flow when the ozone decomposing unit moves from the passing state to the decomposed state in a state where the shut-off valve is in a shut-off state The ozone control device according to claim 9, further comprising: S205). The decomposition execution unit
The ozone control device according to any one of claims 6 to 10, wherein when the internal combustion engine is stopped, the ozone decomposing unit is shifted from the passing state to the decomposing state. The decomposition execution unit
The ozone control device according to any one of claims 6 to 11, wherein when the generation of ozone by the ozone generation unit is stopped, the ozone decomposition unit is shifted from the passage state to the decomposition state.

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