JP2011213560A - Ozone supply apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ozone supply apparatus capable of supplying required ozone supply amount to exhaust gas even if the required ozone supply amount temporarily exceeds a rated value.SOLUTION: The ozone supply apparatus is mounted in a vehicle and supplies ozone to an exhaust gas, and comprises an electric discharge means, a gas supply means, an adjusting means, and a control means. The electric discharge means, for example, an electric discharge container, is provided on a passage connected to an exhaust passway and generates ozone by discharging. The gas supply means is provided on the passage on the upstream side of the electric discharge means and supplies gas including oxygen to the electric discharge means. The adjusting means adjusts a flow rate of the gas supplied from the electric discharge means to the exhaust passage. The control means stores gas in the electric discharge means by limiting the flow rate of the gas supplied from the electric discharge means to the exhaust passage and discharges by the electric discharge means in the case where the supply of ozone to the exhaust gas is not required and a load applied on power source of the electric discharge means becomes less than a prescribed value.

Description

  The present invention relates to an ozone supply device that supplies ozone to exhaust gas.

  In recent years, in order to improve the purification performance of exhaust purification devices such as catalysts, it has been proposed to provide an ozone supply device that supplies ozone to exhaust gas. As this type of technology, the following Patent Document 1 discloses that when the concentration of nitrogen oxide (NOx) in the exhaust gas is equal to or higher than a predetermined concentration, the ozone supply device is operated to exhaust ozone upstream of the catalyst. Techniques for feeding the passage are described. Patent Document 2 also describes a technique related to the present invention.

JP 2009-47117 A JP 2009-281290 A

  Incidentally, the ozone supply amount supplied by the ozone supply device is determined according to the NOx emission amount in the exhaust gas exhausted from the engine. However, the NOx emission amount is not always constant, and when the load is high such as during vehicle acceleration, the NOx emission amount is several times the average value. That is, at this time, it is necessary to temporarily increase the ozone supply amount to match the NOx emission amount. On the other hand, in the technique described in Patent Document 1, when the NOx emission amount temporarily increases and the required ozone supply amount temporarily exceeds the rated value of the ozone supply amount per unit time, the required ozone It is difficult to supply ozone for the supply amount to the exhaust gas.

  Here, when trying to increase the rated value of the ozone supply device, if the size of the ozone supply device is increased, there is a risk of inconvenience in mounting, and the ozone supply capability of the ozone supply device itself has been increased. In some cases it can be costly.

  The present invention has been made in view of the above points, and even when the required ozone supply amount temporarily exceeds the rated value, ozone corresponding to the required ozone supply amount can be supplied to the exhaust gas. It is an object to provide an ozone supply device.

  In one aspect of the present invention, an ozone supply device that is mounted on a vehicle and supplies ozone to exhaust gas in an exhaust passage, the ozone supply device is provided on a passage connected to the exhaust passage, and discharges ozone. A gas supply means for supplying a gas containing oxygen to the discharge means; and a gas supplied from the discharge means to the exhaust passage. Adjusting means for adjusting the flow rate of the exhaust gas, and control means for controlling the discharging means and the adjusting means. The control means does not require supply of ozone to the exhaust gas, and is used as a power source for the discharging means. When the load is less than a predetermined value, the flow rate of the gas supplied from the discharge means to the exhaust passage is limited, the gas is accumulated in the discharge means, and the discharge by the discharge means is performed. Cormorant.

  The ozone supply device is an ozone supply device that is mounted on a vehicle and supplies ozone to exhaust gas, and includes discharge means, gas supply means, adjustment means, and control means. The discharge means is, for example, a discharge reactor, is provided on a passage connected to the exhaust passage, and generates ozone by performing discharge. The gas supply means is, for example, a pump and is provided on a passage on the upstream side of the discharge means, and supplies a gas containing oxygen to the discharge means. The adjusting means is, for example, a switching valve, and adjusts the flow rate of the gas supplied from the discharging means to the exhaust passage. The control means is, for example, an ECU (Electronic Control Unit). When the supply of ozone to the exhaust gas is unnecessary and the load applied to the power supply of the discharge means is less than a predetermined value, the discharge means discharges from the discharge means. The flow rate of the gas supplied to the passage is limited to accumulate gas in the discharge means, and discharge by the discharge means is performed. Here, the predetermined value is a conforming value obtained in advance by experiments or the like. By doing in this way, even if the required ozone supply amount temporarily exceeds the rated value, it becomes possible to supply ozone corresponding to the required ozone supply amount to the exhaust gas.

  In another aspect of the ozone supply device, the control means intermittently controls the flow rate of gas supplied from the gas supply means to the discharge means when supplying ozone to the exhaust gas. This makes it possible to temporarily supply more ozone to the exhaust gas.

  In a preferred embodiment of the ozone supply device, the control means controls the adjustment means when the NOx emission amount is expected to exceed a limit value, thereby controlling the gas accumulated in the discharge means. Supply to the exhaust passage. Here, the limit value is the NOx emission amount when the required ozone supply amount becomes the rated value.

  An ozone supply device that is mounted on a vehicle and supplies ozone to exhaust gas in an exhaust passage, provided on a passage connected to the exhaust passage, and discharge means for generating ozone by discharging, A gas supply means provided on the passage upstream of the discharge means and supplying a gas containing oxygen to the discharge means; and an adjustment means for adjusting a flow rate of the gas supplied from the discharge means to the exhaust passage; Control means for controlling the discharge means and the adjustment means, the control means need not supply ozone to the exhaust gas, and the load applied to the power source of the discharge means is less than a predetermined value. If so, the flow of gas supplied from the discharge means to the exhaust passage is limited to accumulate the gas in the discharge means, and discharge by the discharge means is performed. As a result, even if the required ozone supply amount temporarily exceeds the rated value, it is possible to supply ozone corresponding to the required ozone supply amount to the exhaust gas.

1 is a diagram schematically illustrating an overall configuration of a vehicle according to a first embodiment. It is a graph which shows the relationship between the pulse voltage and produced | generated ozone concentration in case a gas flow rate is constant in a discharge reactor. It is a graph which shows the change of the ozone supply amount with respect to time at the time of controlling a gas flow rate intermittently. It is a graph which shows the change with respect to time of NOx discharge | emission amount and ozone supply amount. It is a figure which shows roughly the whole structure of the vehicle which concerns on 2nd Embodiment. It is a time chart which shows the gas flow rate in each discharge reactor, and the timing of discharge.

  Preferred embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment]
First, a first embodiment of the present invention will be described. FIG. 1 schematically shows an overall configuration of a vehicle 100 equipped with an ozone supply device according to the first embodiment. In FIG. 1, a solid line arrow indicates a gas flow, and a broken line arrow indicates a signal flow.

  The vehicle 100 includes an engine 1, an exhaust purification device 2, and an ozone supply device 3, and includes various sensors for detecting the operating state of the engine 1 such as a crank angle sensor 4 and an accelerator opening sensor 5.

  An exhaust passage 83 provided with the exhaust purification device 2 is attached to the engine 1. The air-fuel mixture combusted in the engine 1 is discharged as exhaust gas into the exhaust passage 83 through the exhaust valve in the exhaust stroke.

The exhaust purification device 2 is, for example, a NOx occlusion reduction catalyst, and stores NOx in exhaust gas in a leaner, that is, oxygen-excess oxidizing atmosphere than stoichiometric, and is richer than stoichiometric, that is, an excess fuel reducing atmosphere or In the stoichiometry, the stored NOx is released and this NOx is reduced and purified. NOx occlusion is realized by oxidizing NOx and occlusion in the NOx occlusion substance as nitrates such as higher-order nitrogen oxides Ba (NO ₃ ) ₂ . For this reason, in order to efficiently perform the NOx occlusion reduction reaction, it is desirable that NOx in the exhaust gas exists as higher-order nitrogen oxides such as higher-order NO ₃ and N ₂ O ₅ than NO _2. . Therefore, the vehicle 100 is provided with an ozone supply device 3 for supplying ozone to the exhaust passage 83 on the upstream side of the exhaust purification device 2. By supplying ozone to the exhaust gas, NOx in the exhaust gas reacts with ozone, and the generation of higher-order nitrogen oxides such as NO ₃ and N ₂ O ₅ is promoted.

  The ozone supply device 3 includes a pump 20, an air cleaner 40, a discharge reactor 30, and a control unit 11.

  The pump 20 is connected to the discharge reactor 30 via a passage 82, and supplies oxygen-containing gas to the discharge reactor 30 via the passage 82. The pump 20 can compress the gas and supply it to the discharge reactor 30. For example, the pump 20 cleans the air taken from the outside through the air cleaner 40 and compresses and supplies it to the discharge reactor 30.

  The discharge reactor 30 has a plurality of electrodes (not shown) and is connected to an exhaust passage 83 on the upstream side of the exhaust purification device 2 via a passage 82. In the ozone supply device 3, by generating discharge between a plurality of electrodes, a gas containing oxygen reacts to generate ozone. The discharge reactor 30 is driven by a drive signal from the control unit 11. Specifically, in the discharge reactor 30, a pulse voltage is applied between the plurality of electrodes according to the drive signal from the control unit 11.

  The gas supplied by the pump 20 reaches the discharge reactor 30 and then reaches the exhaust passage 83 from the passage 82 together with the generated ozone. Thus, the ozone generated in the discharge reactor 30 is supplied to the exhaust gas in the exhaust passage 83 on the upstream side of the exhaust purification device 2. The pump 20 is driven by a drive signal from the control unit 11. Specifically, in the pump 20, the gas flow rate is adjusted according to the drive signal from the control unit 11. A gas flow meter 50 is provided in the passage 82. The gas flow meter 50 detects the gas flow rate in the passage 82 and transmits a detection signal corresponding to the detected gas flow rate to the control unit 11.

  The control unit 11 is an ECU (Electronic Control Unit), for example, and includes a CPU (Central Processing Unit) and a memory. The control unit 11 obtains the operating state of the engine 1 based on detection signals from various sensors such as the crank angle sensor 4 and the accelerator opening sensor 5. Further, the control unit 11 has a map showing the relationship between the operation state of the engine 1 and the NOx emission amount, and based on the operation state of the engine 1 obtained based on detection signals from various sensors, The NOx emission amount is obtained using a map. Then, the control unit 11 obtains an appropriate ozone amount (hereinafter referred to as “required ozone supply amount”) for efficiently performing the NOx occlusion reduction reaction based on the obtained NOx emission amount, and the pump 20 and The discharge reactor 30 is controlled to supply the required ozone supply amount of ozone to the exhaust gas.

  Next, a control method of the ozone supply device 3 according to the first embodiment will be described.

  The ozone supply amount supplied from the ozone supply device 3 to the exhaust passage 83 is proportional to the gas flow rate of the pump 20, the discharge operating voltage that is the amplitude of the pulse voltage in the discharge reactor 30, and the pulse repetition number of the pulse voltage. Therefore, when the number of pulse repetitions of the pulse voltage is constant, the ozone supply amount is proportional to the gas flow rate and the discharge operating voltage.

  The relationship between the discharge operating voltage and the generated ozone concentration will be described using the graph shown in FIG. FIG. 2 is a graph showing the relationship between the discharge operating voltage and the generated ozone concentration when the gas flow rate is constant in the discharge reactor 30.

  As can be seen from FIG. 2, when the gas flow rate is constant, when the discharge operating voltage becomes V1 or higher, ozone is generated and the generated ozone concentration starts to rise rapidly. The generated ozone concentration at this time is N1. Further, the generated ozone concentration is saturated when the discharge operating voltage exceeds V2 (> V1). The generated ozone concentration when the discharge operating voltage is V2 is N2. The control unit 11 changes the generated ozone concentration between N1 and N2 by controlling the discharge operating voltage between V1 and V2. The discharge operating voltage V2 is a value that is determined in advance based on, for example, energy efficiency. Here, when the gas flow rate is constant, the ozone supply amount per unit time when the discharge operation voltage becomes V2 is the rated value of the ozone supply amount (hereinafter simply referred to as “rated value”).

  Therefore, when the NOx emission amount exceeds the limit value (NOx emission amount when the NOx required ozone supply amount becomes the rated value) while the gas flow rate is kept constant, the ozone supply device 3 determines the NOx. It becomes difficult to supply ozone for the required ozone supply amount to the exhaust gas.

  Therefore, in the control method of the ozone supply device 3 according to the first embodiment, the intermittent operation of the pump 20 is performed, and the gas flow rate supplied to the discharge reactor 30 is intermittently controlled, so that the ozone per unit time is The supply amount will be temporarily larger than the rated value. Hereinafter, a description will be given with reference to FIG.

  FIG. 3 is a graph showing a change in ozone supply amount per unit time with respect to time when the gas flow rate is intermittently controlled. In FIG. 3, the rated value is shown as Nt.

  In the example shown in FIG. 3, the discharge operating voltage is set to V2, and the intermittent operation of the pump 20 is performed in the intermittent pump operation periods Ta and Tb. For example, in the pump intermittent operation period Ta, intermittent operation in which the pump 20 is stopped for 2 seconds and then operated for 2 seconds is repeated, and in the pump intermittent operation period Tb, intermittent operation in which the pump 20 is stopped for 3 seconds and then operated for 2 seconds. Is repeated. In this way, when ozone is supplied to the exhaust gas in the pump intermittent operation periods Ta and Tb, that is, when the pump 20 is operated, the ozone supply amount per unit time is larger than the rated value Nt. can do. For example, in the pump intermittent operation period Ta, while the pump 20 is stopped for 2 seconds, the discharge reactor 30 generates ozone for 2Nt that is twice the rated value Nt. Therefore, after that, the ozone supply amount per unit time while the pump 20 is operated for 2 seconds is equal to the ozone generation amount Nt generated per unit time at the time of the operation, per unit time of accumulated ozone. Supply amount: 2Nt / 2 = Nt obtained by adding Nt.

  In the intermittent pump operation period Tb, while the pump 20 is stopped for 4 seconds, the discharge reactor 30 generates ozone for 3 Nt, which is three times the rated value Nt. Therefore, after that, the ozone supply amount per unit time while the pump 20 is operated for 2 seconds is equal to the ozone generation amount Nt generated per unit time at the time of the operation, per unit time of accumulated ozone. Supply amount: 4Nt / 2 = 2Nt plus 3Nt.

  Thus, by performing the intermittent operation of the pump 20, the ozone supply amount per unit time can be temporarily increased from the rated value. Thereby, even if the NOx emission amount exceeds the limit value and the required ozone supply amount temporarily exceeds the rated value, the ozone supply device 3 supplies ozone corresponding to the required ozone supply amount to the exhaust gas. It becomes possible to do.

  FIG. 4 is a graph showing changes in NOx emission amount and ozone supply amount with respect to time. FIG. 4A is a graph showing a change with respect to time of the NOx emission amount, and FIG. 4B is a graph showing a change with time of the ozone supply amount supplied according to the NOx emission amount.

  As shown in the graph of FIG. 4 (a), the NOx emission amount greatly exceeds the average NOx emission amount and temporarily exceeds the limit value due to vehicle acceleration or the like between time tp1 and time tp2. Suppose that At this time, the required ozone supply amount also temporarily exceeds the rated value. Therefore, if the ozone supply device 3 predicts that the NOx emission amount exceeds the limit value based on the operating state of the engine 1, that is, if it is predicted that the required ozone supply amount exceeds the rated value, the intermittent operation of the pump 20 is performed. Start driving. In the example shown in FIG. 4, at time tp0 (<time tp1), the ozone supply device 3 predicts that the required ozone supply amount exceeds the rated value based on the operating state of the engine 1, and intermittently operates the pump 20. To start. By doing in this way, even when the required ozone supply amount exceeds the rated value Nt at times tp1 to tp2, the ozone supply device 3 can supply ozone for the required ozone supply amount to the exhaust gas. It becomes possible.

  In the example shown in FIGS. 3 and 4, the intermittent operation of the pump 20 is started after the NOx emission amount is predicted to exceed the limit value, but the present invention is not limited to this. It goes without saying that intermittent operation of the pump 20 may always be performed instead of doing this.

  As can be seen from the above description, in the first embodiment, the ozone supply device 3 performs intermittent operation of the pump 20 to intermittently control the gas flow rate supplied to the discharge reactor 30. As a result, even if the NOx emission amount exceeds the limit value, that is, the required ozone supply amount temporarily exceeds the rated value Nt, the ozone supply device 3 reduces the ozone for the required ozone supply amount. It becomes possible to supply exhaust gas.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. The ozone supply device according to the second embodiment does not require ozone supply to the exhaust gas, and when the load applied to the power source of the discharge reactor is less than a predetermined value, A high concentration of ozone will be generated and stored. This will be specifically described below with reference to FIG.

  FIG. 5 schematically shows an overall configuration of a vehicle 100a to which the ozone supply device according to the second embodiment is applied. In FIG. 5, a solid line arrow indicates a gas flow, and a broken line arrow indicates a signal flow. In FIG. 5, the same components as those in FIG. 1 are denoted by the same reference numerals as those in FIG. 1, and detailed description thereof is omitted.

  As shown in FIG. 5, in the vehicle 100 a according to the second embodiment, the ozone supply device 3 a further includes a discharge reactor 31 in parallel with the discharge reactor 30. Specifically, a passage 84 that bypasses the discharge reactor 30 with respect to the passage 82 is provided, and the discharge reactor 31 is provided on the passage 84. A switching valve 51 is provided in the passage 82 upstream of the discharge reactor 30 and downstream of the branch with the passage 84, and upstream of the discharge reactor 31 and downstream of the branch. A switching valve 52 is provided in the passage 84. A switching valve 53 is provided in the passage 84 on the downstream side of the discharge reactor 31. These switching valves 51, 52, 53 are adjusting valves for adjusting the gas flow rate, and are controlled by the control unit 11.

  Next, a control method of the ozone supply device 3a according to the second embodiment will be described.

  When ozone supply to the exhaust gas is necessary and the required ozone supply amount is less than the rated value, the switching valve 51 is controlled to the opening side, and the switching valves 52 and 53 are controlled to the closing side. . At this time, gas is supplied from the pump 30 to the discharge reactor 30, and ozone is generated in the discharge reactor 30. Then, ozone generated in the discharge reactor 30 is supplied to the exhaust passage 83 together with the gas, and ozone is supplied to the exhaust gas.

  When the supply of ozone to the exhaust gas is unnecessary and the load applied to the power source of the discharge reactor 31 is less than a predetermined value, the switching valves 51 and 53 are controlled to the closed side, and the switching valve 52 Is controlled to open. At this time, although gas is supplied from the pump 30 to the discharge reactor 31, supply of gas from the discharge reactor 31 to the exhaust passage 83 is stopped, so that gas is accumulated in the discharge reactor 31. Here, when discharge is performed in the discharge reactor 81, ozone is generated, and the ozone concentration in the discharge reactor 31 increases. Here, the predetermined value is a conforming value determined in advance by experiments or the like.

  When ozone supply to the exhaust gas is required and the required ozone supply amount becomes larger than the rated value, in addition to controlling the switching valve 51 to the opening side, the switching valves 52 and 53 are also set to the opening side. Control. Thus, not only the ozone generated in the discharge reactor 30 but also the ozone generated and accumulated in the discharge reactor 31 is supplied to the exhaust passage 83 together with the gas, and the accumulated ozone is also supplied to the exhaust gas. . By doing in this way, even if the NOx emission amount exceeds the limit value and the required ozone supply amount temporarily exceeds the rated value, the ozone supply device 3 is capable of the required ozone supply amount. It becomes possible to supply ozone to the exhaust gas.

  The gas flow rate and discharge timing in each discharge reactor will be described with reference to the time chart of FIG. FIG. 6A shows the change of the gas flow rate in the discharge reactor 31 with respect to time, and FIG. 6B shows the change of the gas flow rate in the discharge reactor 30 with respect to time. 6C shows the change of the discharge power in the discharge reactor 31 with respect to time, and FIG. 6D shows the change of the discharge power in the discharge reactor 30 with respect to time. In the following, description will be given in time series.

  It is assumed that ozone supply to the exhaust gas is unnecessary between time t1 and time t2, and the load applied to the power source of the discharge reactor 31 is less than a predetermined value. Therefore, at time t1, the control unit 11 controls the switching valves 51 and 53 to the closed side and controls the switching valve 52 to the open side to supply the gas from the pump 20 to the discharge reactor 31 for accumulation. To do. At time t <b> 2, the control unit 11 generates and accumulates ozone in the discharge reactor 31 by applying a pulse voltage between the plurality of electrodes in the discharge reactor 31. At time t <b> 3, the control unit 11 stops applying the pulse voltage to the electrodes in the discharge reactor 31 and completes generation and accumulation of ozone in the discharge reactor 31.

  At time t4, when the control unit 11 detects that NOx is discharged based on the operating state of the engine 1, in other words, the control unit 11 has a NOx emission amount that should supply ozone to the exhaust gas. Is detected, supply of ozone to the exhaust passage 83 is started. Specifically, the control unit 11 supplies the gas from the pump 20 to the discharge reactor 30 while controlling the switching valve 51 to the open side and keeping the switching valves 52 and 53 closed. Thereby, ozone is generated in the discharge reactor 30, and the generated ozone is supplied to the exhaust passage 83. In addition, the required ozone supply amount at this time shall be below the rated value.

  At time t5, the NOx emission amount exceeds the limit value, and the required ozone supply amount exceeds the rated value. When the control unit 11 predicts that the NOx emission amount exceeds the limit value based on the operating state of the engine 1, that is, when it is predicted that the required ozone supply amount exceeds the rated value, the control valve 51 opens the switching valve 51. In addition to the control, the switching valves 52 and 53 are also controlled to open. Thereby, not only the ozone generated in the discharge reactor 30 but also the ozone generated and accumulated in the discharge reactor 31 is supplied to the exhaust gas. By doing in this way, even if the NOx emission amount exceeds the limit value and the required ozone supply amount exceeds the rated value, it is possible to supply ozone for the required ozone supply amount to the exhaust gas. Become.

  At time t6, the NOx emission amount becomes equal to or less than the limit value, and the required ozone supply amount becomes equal to or less than the rated value. When the control unit 11 predicts that the NOx emission amount is below the limit value based on the operating state of the engine 1, that is, when it is predicted that the required ozone supply amount is below the rated value, the control unit 11 opens the switching valve 51. In the state controlled to the side, the switching valves 52 and 53 are controlled to the closed side, and only the ozone generated in the discharge reactor 30 is supplied to the exhaust passage 83. At time t <b> 7, the control unit 11 stops supplying ozone to the exhaust passage 83 based on the operating state of the engine 1. Specifically, the control unit 11 controls the switching valve 51 to close to stop the supply of ozone to the exhaust gas.

  After time t8, the same control as the control performed between time t1 and time t7 described above is repeatedly performed. Specifically, between time t8 and time t10, ozone supply to the exhaust gas is necessary, and the load applied to the power source of the discharge reactor 31 is less than a predetermined value, so time t1 to time t3 The same control as that performed until is performed. Specifically, at time t8, the control unit 11 controls the switching valves 51 and 53 to the closed side and controls the switching valve 52 to the open side to supply the gas from the pump 20 to the discharge reactor 31. And accumulate. At time t <b> 9, the controller 11 generates and accumulates ozone in the discharge reactor 31 by applying a pulse voltage between the plurality of electrodes in the discharge reactor 31. At time t <b> 10, the control unit 11 stops applying the pulse voltage to the electrodes in the discharge reactor 31 and ends the generation and accumulation of ozone in the discharge reactor 31.

  As can be seen from the above description, the ozone supply device 3a according to the second embodiment does not require ozone supply to the exhaust gas, and the load applied to the power source of the discharge reactor 31 is less than a predetermined value. At this time, the switching valve 53 is controlled to the closed side, and the supply of gas from the discharge reactor 31 to the exhaust passage 83 is stopped. As a result, ozone is accumulated in the discharge reactor 31 to generate high-concentration ozone. Even if the required ozone supply amount temporarily exceeds the rated value, the ozone supply device 3a can supply ozone corresponding to the required ozone supply amount to the exhaust gas. In the second embodiment described above, the switching valve 53 is controlled to be closed, and the supply of gas from the discharge reactor 31 to the exhaust passage 83 is stopped. However, the present invention is not limited to this. It goes without saying that the gas supply amount may be limited instead of completely stopping the gas supply from the discharge reactor 31 to the exhaust passage 83.

[Modification]
In addition, this invention is not limited to the above-mentioned embodiment, It can implement with a various form within the range of the summary of this invention.

  For example, the ozone supply device control methods according to the first and second embodiments described above may be combined. For example, in the second embodiment, when the gas is supplied to the discharge reactor 30 and the ozone generated in the discharge reactor 30 is supplied to the exhaust gas, or in addition, the discharge reactor 31 is also supplied. When supplying gas and supplying ozone accumulated in the discharge reactor 31 to the exhaust gas, the controller 11 may intermittently operate the pump 20. This makes it possible to temporarily supply more ozone to the exhaust gas.

  Further, the ozone supply device 3a according to the second embodiment described above includes the discharge reactors 30 and 31, but is not limited thereto. Instead of doing this, the ozone supply device 3 a may include only the discharge reactor 31.

  In each of the above-described embodiments, a NOx storage reduction catalyst is used as the exhaust purification device 2, but it goes without saying that the present invention is not limited to this. For example, when the engine 1 is a diesel engine, an oxidation catalyst and a DPF (Diesel Particulate Filter) may be used as the exhaust purification device 2 instead of the NOx storage reduction catalyst. The oxidation catalyst is a catalyst configured to be able to oxidize CO, HC (mainly SOF), NO and the like contained in exhaust gas. The DPF is a filter configured to capture PM (particulate matter) in the exhaust gas. Even when ozone is supplied from the ozone supply devices 3 and 3a together with the exhaust gas to the exhaust gas purification device 2, the function of the oxidation catalyst can be improved because the oxidizing power of ozone is high.

  Further, in each of the above-described embodiments, the control unit 11 obtains the NOx emission amount based on the operating state of the engine 1 and obtains the required ozone supply amount based on the NOx emission amount, but is not limited thereto. . Instead of this, it is assumed that a NOx sensor for detecting the NOx concentration is provided in the exhaust passage 83 upstream of the exhaust purification device 2, and the control unit 11 determines the NOx emission amount based on the detection signal from the NOx sensor. And the required ozone supply amount may be obtained based on the NOx emission amount.

DESCRIPTION OF SYMBOLS 1 Engine 2 Exhaust gas purification device 3 Ozone supply device 4 Crank angle sensor 5 Accelerator opening degree sensor 11 Control part 20 Pump 30 Discharge reactor

Claims (3)

An ozone supply device mounted on a vehicle and supplying ozone to exhaust gas in an exhaust passage,
A discharge means provided on a passage connected to the exhaust passage and generating ozone by performing discharge;
A gas supply means provided on the passage on the upstream side of the discharge means, for supplying a gas containing oxygen to the discharge means;
Adjusting means for adjusting the flow rate of the gas supplied from the discharging means to the exhaust passage;
Control means for controlling the discharging means and the adjusting means,
When the supply of ozone to the exhaust gas is unnecessary and the load applied to the power source of the discharge means is less than a predetermined value, the control means supplies the gas from the discharge means to the exhaust passage. The ozone supply device is characterized in that the gas is accumulated in the discharge means while limiting discharge and the discharge by the discharge means is performed.   The ozone supply device according to claim 1, wherein the control means intermittently controls a gas flow rate supplied from the gas supply means to the discharge means when supplying ozone to the exhaust gas.   The control unit according to claim 1 or 2, wherein when the NOx emission amount is predicted to exceed a limit value, the control unit supplies the gas accumulated in the discharge unit to the exhaust passage by controlling the adjustment unit. The ozone supply device described.

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