JP2022104111A - Post-exhaust treatment device - Google Patents

Abstract

To provide a post-exhaust treatment device which is suppressed in power consumption when maintaining a temperature of an SCR catalyst, and has no risk that fuel economy is largely deteriorated.SOLUTION: In a post-exhaust treatment device 100, an oxidization catalyst 103, a first PM collection filter 104, a valve body 106 and an SCR catalyst 105 are sequentially arranged from an exhaust upstream side toward an exhaust downstream side of an exhaust flow passage 102 of an internal combustion engine 101, a heater 110 and a second PM collection filter 111 are sequentially arranged from an exhaust upstream side toward an exhaust downstream side of a bypass flow passage 109 in which an exhaust upstream-side end 107 is connected to the exhaust flow passage 102 at an exhaust upstream side of the oxidization catalyst 103 as well as an exhaust downstream-side end 108 is connected to the exhaust flow passage 102 at an exhaust downstream side of the valve body 106 and at an exhaust upstream side of the SCR catalyst 105, the valve body 106 is closed when the lowering of a temperature of the SCR catalyst 105 resulting from the lowering of an exhaust temperature is concerned, and the valve body 106 is opened when the lowering of the temperature of the SCR catalyst 105 resulting from the lowering of the exhaust temperature is not concerned.SELECTED DRAWING: Figure 1

Description

The present invention relates to an exhaust aftertreatment device that purifies the exhaust gas of an internal combustion engine.

PM (Particulate Matter ) collection filters and SCR ( Slective Catalytic Reduction ) catalysts are used to purify the exhaust gas of internal combustion engines.

In the SCR catalyst, nitrogen oxides (NO _X ) in the exhaust gas of the internal combustion engine can be efficiently purified by maintaining the temperature of the SCR catalyst above the activation temperature.

A technique is known in which the temperature of the SCR catalyst is maintained by heating the exhaust gas with a heating device installed in the exhaust flow path when the exhaust gas temperature is low (see, for example, Patent Document 1).

There is also known a technique of switching between a flow path in which exhaust gas flows to a heating device and a flow path in which exhaust gas does not flow to a heating device based on the exhaust temperature (see, for example, Patent Document 2).

Japanese Unexamined Patent Publication No. 2010-265862 Japanese Unexamined Patent Publication No. 2020-7325

For example, EHC ( Electrically H eated Catalyst) as a heating device and DOC ( Diesel Oxidation C ) as an oxidation catalyst from the exhaust upstream side to the exhaust downstream side of the exhaust flow path of a diesel engine as an internal combustion engine. Assuming a configuration in which atalyst ), CSF (Catalyzed S oot Filter) as a PM collection filter, and an SCR catalyst as a denitration catalyst are sequentially arranged, EHC is used to maintain the temperature of the SCR catalyst. Since it is necessary to heat not only the SCR catalyst but also the DOC and CSF having a large heat capacity, there is a concern that the power consumption will increase and the fuel efficiency will be significantly deteriorated.

In view of the above circumstances, it is an object of the present invention to provide an exhaust aftertreatment device which consumes less power and does not have a risk of significantly deteriorating fuel consumption when maintaining the temperature of the SCR catalyst.

An oxidation catalyst installed in the exhaust flow path of the internal combustion engine, a first PM collection filter installed in the exhaust flow path and arranged on the exhaust downstream side of the oxidation catalyst, and installed in the exhaust flow path. In an exhaust aftertreatment device that comprises an SCR catalyst arranged on the exhaust downstream side of the first PM collection filter and purifies the exhaust of the internal combustion engine, the first PM is installed in the exhaust flow path. A valve body arranged on the exhaust downstream side of the collection filter and on the exhaust upstream side of the SCR catalyst, and an exhaust upstream end are connected to the exhaust flow path on the exhaust upstream side of the oxidation catalyst, and the exhaust downstream of the valve body are connected. A detour flow path in which the exhaust downstream end is connected to the exhaust flow path on the side and on the exhaust upstream side of the SCR catalyst, a heating device installed in the detour flow path, and the heating device installed in the detour flow path. Further provided with a second PM collection filter located on the downstream side of the exhaust of the apparatus, the valve body is closed when there is a concern that the temperature of the SCR catalyst will decrease due to a decrease in the exhaust temperature, and the exhaust temperature will be reduced. Provided is an exhaust aftertreatment device which is opened when there is no concern about a temperature drop of the SCR catalyst due to a drop in the temperature of the SCR catalyst.

It is desirable that the detour flow path has a smaller maximum flow rate than the exhaust flow path.

It is desirable that the capacity of the second PM collection filter is smaller than that of the first PM collection filter.

The heating device may be operated when there is a concern that the temperature of the SCR catalyst may decrease due to a decrease in the exhaust temperature, and may be stopped when there is no concern about a temperature decrease of the SCR catalyst due to a decrease in the exhaust temperature. desirable.

When there is a concern that the temperature of the SCR catalyst will drop due to a drop in the exhaust temperature, the fuel injection amount of the internal combustion engine tends to decrease or no injection occurs when the vehicle equipped with the internal combustion engine is in a decelerated state. In some cases, when the vehicle is stopped and the internal combustion engine is idling, and there is no concern about a decrease in the temperature of the SCR catalyst due to a decrease in the exhaust temperature, the vehicle is in a non-deceleration state. It is desirable that there is a case or that the vehicle is in a non-stop state.

It is assumed that the opening degree of the valve body is reduced when the temperature drop of the SCR catalyst is assumed to be large due to the decrease in the exhaust temperature, and the temperature decrease of the SCR catalyst due to the decrease in the exhaust temperature is small. In this case, the opening degree is increased, and it is desirable that the SCR catalyst is fully opened when there is no concern about the temperature decrease of the SCR catalyst due to the decrease in the exhaust temperature.

When maintaining the temperature of the SCR catalyst, it is possible to provide an exhaust aftertreatment device that consumes less power and does not have a risk of significantly deteriorating fuel efficiency.

It is a figure explaining the exhaust gas aftertreatment apparatus which concerns on embodiment.

As shown in FIG. 1, the exhaust aftertreatment device 100 purifies the exhaust gas of the internal combustion engine 101, and is installed in the oxidation catalyst 103 installed in the exhaust flow path 102 of the internal combustion engine 101 and in the exhaust flow path 102. The first PM collection filter 104 installed on the exhaust downstream side of the oxidation catalyst 103 and the SCR catalyst 105 installed on the exhaust flow path 102 and arranged on the exhaust downstream side of the first PM collection filter 104. And.

The internal combustion engine 101 is, for example, a diesel engine or a gasoline engine mounted on a moving body (for example, a vehicle) or a non-moving body (for example, an industrial machine). The oxidation catalyst 103 is, for example, DOC or TWC (Three Way Catalyst). The first PM collection filter 104 is, for example, a CSF or a DPF ( Diesel Particulate Filter). The SCR catalyst 105 is, for example, a urea SCR catalyst.

As described above, in order to efficiently purify the nitrogen oxides in the exhaust gas, it is desirable that the temperature of the SCR catalyst 105 is maintained above the activation temperature, but the vehicle equipped with the internal combustion engine 101 decelerates. When the fuel injection amount of the internal combustion engine 101 tends to decrease or is not injected in the state, or when the internal combustion engine 101 is idling while the vehicle is stopped, the exhaust temperature becomes low, so that the SCR catalyst is used. There is a problem that the heat of the 105 is taken away by the low-temperature exhaust flowing through the SCR catalyst 105, and the temperature of the SCR catalyst 105 also becomes low.

In order to solve this problem, the exhaust aftertreatment device 100 is installed in the exhaust flow path 102, and the valve body 106 is arranged on the exhaust downstream side of the first PM collection filter 104 and on the exhaust upstream side of the SCR catalyst 105. The exhaust upstream end 107 is connected to the exhaust flow path 102 on the exhaust upstream side of the oxidation catalyst 103, and the exhaust downstream end 108 is connected to the exhaust flow path 102 on the exhaust downstream side of the valve body 106 and on the exhaust upstream side of the SCR catalyst 105. The detour flow path 109, the heating device 110 installed in the detour flow path 109, and the second PM collection filter 111 installed in the detour flow path 109 and arranged on the exhaust downstream side of the heating device 110. Further prepare.

The valve body 106 is, for example, a solenoid valve whose opening and closing is controlled by an ECU ( E lectronic (or Engine) C ontrol Unit) 112. The heating device 110 is, for example, an EHC or an electric heater whose operation stop (whether or not power is supplied) is controlled by the ECU 112. The second PM collection filter 111 is, for example, a CSF or a DPF.

For the sake of simplification of the following description, the flow path through which the exhaust gas flows through the oxidation catalyst 103 and the first PM collection filter 104 to the SCR catalyst 105 is referred to as the main flow path R1 (dashed-dotted line arrow in FIG. 1). The flow path through which the exhaust gas flows through the heating device 110 and the second PM collection filter 111 to the SCR catalyst 105 is referred to as an auxiliary flow path R2 (two-dot chain line arrow in FIG. 1). Since the main flow path R1 is a general flow path that has been widely used in the past, detailed description of the structure and operation of the main flow path R1 will be omitted. A part of the main flow path R1 and the sub flow path R2 (solid line arrow in FIG. 1) is common.

The valve body 106 is closed when there is a concern that the temperature of the SCR catalyst 105 will decrease due to a decrease in the exhaust temperature (for example, it is fully closed), and there is a concern that the temperature of the SCR catalyst 105 will decrease due to a decrease in the exhaust temperature. If not, it will be opened (for example, fully open).

When the valve body 106 is fully closed, the main flow path R1 is shut off and the exhaust does not flow into the main flow path R1, so that the temperature of the main flow path R1 drops due to the drop in the exhaust temperature, the temperature of the oxidation catalyst 103 drops, and the first One PM collection filter 104 can suppress the temperature drop, and all the exhaust gas flows to the sub-flow path R2, and the exhaust gas is heated by the heating device 110. Therefore, the SCR catalyst 105 caused by the drop in the exhaust gas temperature It is possible to suppress the temperature drop.

When the valve body 106 is fully opened again after the valve body 106 is fully closed, the main flow path R1 is opened and the exhaust flows into the main flow path R1 again, but while the valve body 106 is fully closed. Since the temperature decrease of the main flow path R1, the temperature decrease of the oxidation catalyst 103, and the temperature decrease of the first PM collection filter 104 are suppressed, the temperature of the exhaust flowing to the main flow path R1 is difficult to decrease, and the temperature of the SCR catalyst 105 decreases. Is unlikely to occur. When the valve body 106 is fully opened, most of the exhaust gas flows into the main flow path R1, but the sub-flow path R2 is not blocked, so that the remaining exhaust gas that does not flow into the main flow path R1 flows into the sub-flow path R2.

When there is a concern that the temperature of the SCR catalyst 105 will drop due to a drop in the exhaust temperature, the fuel injection amount of the internal combustion engine 101 tends to decrease while the vehicle equipped with the internal combustion engine 101 is in a decelerated state, or there is no injection. In some cases, or when the internal combustion engine 101 is in an idling operation (an operating state in which the engine rotation speed is equal to or lower than the idle (minimum) rotation speed) while the vehicle is stopped, the SCR catalyst is caused by a decrease in the exhaust temperature. The case where there is no concern about a temperature drop is a case where the vehicle is in a non-deceleration state or a case where the vehicle is in a non-stop state. For example, if the accelerator is released while the vehicle is descending a slope, the fuel injection amount of the internal combustion engine 101 tends to decrease or becomes non-injection when the vehicle is decelerated, so that the SCR catalyst 105 due to the decrease in the exhaust temperature There is a concern that the temperature of the engine will drop. In addition, when the vehicle is traveling on a road with many traffic lights and the vehicle has to stop at a red light frequently, and the vehicle repeatedly starts, accelerates, decelerates, and stops, the SCR catalyst 105 cools down by decelerating or stopping. If the vehicle is stopped for a long time, the SCR catalyst 105 will become colder. The engine speed is detected by, for example, the engine speed sensor 113 and is input to the ECU 112.

Even if the valve body 106 is closed at the moment of transition from a state in which the temperature drop of the SCR catalyst 105 due to the decrease in the exhaust temperature is not a concern to a state in which the temperature decrease in the SCR catalyst 105 due to the decrease in the exhaust temperature is a concern. Good, but in order to suppress the temperature drop of the SCR catalyst 105 due to the drop in the exhaust temperature as much as possible, the SCR catalyst caused by the drop in the exhaust temperature from the state where there is no concern about the temperature drop of the SCR catalyst 105 due to the drop in the exhaust temperature. It is desirable to close the 105 in advance when it is likely to transition to a state in which a temperature drop is a concern.

The case where the temperature drop of the SCR catalyst 105 due to the decrease in the exhaust temperature is not a concern is likely to shift to the state in which the temperature drop of the SCR catalyst 105 due to the decrease in the exhaust temperature is a concern is, for example, the engine rotation speed. This is a case where the engine speed is continuously decreasing at a predetermined rate even though the idle speed is exceeded, and the engine speed is likely to be lower than the idle speed in the near future.

Even if the valve body 106 is opened at the moment of transition from a state in which the temperature drop of the SCR catalyst 105 due to the decrease in the exhaust temperature is a concern to a state in which the temperature decrease in the SCR catalyst 105 due to the decrease in the exhaust temperature is not a concern. It is good, but for example, in a traffic situation where there is a lot of traffic congestion or waiting for a signal, there is no concern about the temperature decrease of the SCR catalyst 105 due to the decrease in the exhaust temperature and the temperature decrease of the SCR catalyst 105 due to the decrease in the exhaust temperature. Immediately after the state is repeated in a short time and the state in which the temperature decrease of the SCR catalyst 105 due to the decrease in the exhaust temperature is a concern is changed to the state in which the temperature decrease of the SCR catalyst 105 due to the decrease in the exhaust temperature is not a concern. In many cases, there is a transition from a state in which the temperature drop of the SCR catalyst 105 due to the drop in the exhaust temperature is not a concern to a state in which the temperature drop in the SCR catalyst 105 due to the drop in the exhaust temperature is a concern. There is concern about the temperature decrease of the SCR catalyst 105 due to the decrease in the exhaust temperature after the transition from the state in which the temperature decrease of the SCR catalyst 105 due to the concern to the state in which the temperature decrease of the SCR catalyst 105 due to the decrease in the exhaust temperature is not concerned. It is desirable to open when the non-catalyzed state continues for a predetermined time.

It should be noted that there may be a mode in which the valve body 106 is not only fully closed or fully opened but also has an arbitrary opening degree. For example, the valve body 106 has a small opening when it is assumed that the temperature drop of the SCR catalyst 105 due to the drop in the exhaust temperature is large, and the temperature drop of the SCR catalyst 105 due to the drop in the exhaust temperature is small. It may be fully opened when the opening degree is increased (excluding full opening) when it is assumed and there is no concern about the temperature decrease of the SCR catalyst 105 due to the decrease in exhaust temperature.

The SCR catalyst 105 caused by a decrease in the exhaust temperature while avoiding a fully closed state in which the valve body 106 is not only fully closed or fully opened but also has an arbitrary opening, which causes an increase in exhaust pressure as much as possible. It is possible to suppress the temperature drop.

The case where the temperature drop of the SCR catalyst 105 due to the drop in the exhaust temperature is assumed to be large is, for example, the case where the SCR catalyst 105 is in a low temperature environment (when the outside air temperature is low). The case where the temperature drop of the SCR catalyst 105 due to the drop in the exhaust temperature is assumed to be small is, for example, the case where the SCR catalyst 105 is in a high temperature environment (when the outside air temperature is high). The outside air temperature is, for example, detected by the outside air temperature sensor 114 and input to the ECU 112. It is also possible to estimate the outside air temperature based on the current position information acquired by GPS ( Global Positioning System) and the current date and time information.

In addition to when the engine speed is low (for example, when the engine speed is less than or equal to the idle speed) or when the outside air temperature is low (for example, when the outside air temperature is below freezing point), for example, when the accelerator opening is small and the vehicle speed is slow. Even when the accelerator opening is less than the specified opening and the vehicle speed is less than the specified speed) or the vehicle speed is slow (the vehicle speed is less than the specified speed) and the foot brake is operating, the SCR catalyst caused by the decrease in the exhaust temperature It is desirable that the valve body 106 is closed because there is a concern that the temperature of 105 will drop. The accelerator opening degree is detected by, for example, the accelerator opening degree sensor 115 and is input to the ECU 112. The vehicle speed is detected by, for example, the vehicle speed sensor 116 and is input to the ECU 112. The operating state of the foot brake is detected by, for example, the foot brake sensor 117 and input to the ECU 112.

The detour flow path 109 has a smaller maximum flow rate than the exhaust flow path 102. That is, the sub-flow path R2 has a smaller maximum flow rate than the main flow path R1. For example, as shown in FIG. 1, the minimum flow path cross-sectional area of the exhaust upstream end 107 is the same (common) as the minimum flow path cross-sectional area of the exhaust flow path 102, and the minimum flow path cross-sectional area of the exhaust downstream end 108 is It is made smaller than the minimum flow path cross-sectional area of the exhaust flow path 102.

Since the amount of heat dissipated to the outside is proportional to the surface area of the flow path, the flow path cross-sectional area of the sub-flow path R2 is basically the total length of the sub-flow path R2 in order to suppress heat dissipation in the sub-flow path R2 as much as possible. It is desirable that the design be as small as possible.

As described above, when the valve body 106 is fully closed, all the exhaust gas flows to the sub-flow path R2. Therefore, the amount of exhaust gas flowing to the sub-flow path R2 with the valve body 106 fully closed is used as a reference. The flow path cross-sectional area of the sub-flow path R2 is designed.

For example, in the embodiment in which the valve body 106 is fully closed in a state where there is a concern that the temperature of the SCR catalyst 105 is lowered due to the decrease in the exhaust temperature, the valve body 106 flows into the subchannel R2 in a fully closed state. Since only a small amount of exhaust gas is discharged in a state where there is a concern that the temperature of the SCR catalyst 105 will decrease due to the decrease in the exhaust gas temperature, it is possible to make the flow path cross-sectional area of the sub-flow path R2 relatively small. You can.

When the temperature drop of the SCR catalyst 105 due to the drop in the exhaust temperature is not a concern and the temperature drop of the SCR catalyst 105 due to the drop in the exhaust temperature is likely to shift, the valve body 106 is fully loaded in advance. In the closed mode, the flow path cross-sectional area of the sub-flow path R2 is set based on the maximum amount of exhaust gas that can flow to the sub-flow path R2 with the valve body 106 fully closed.

In FIG. 1, the minimum flow path cross-sectional area of the exhaust upstream end 107 is the same as the minimum flow path cross-sectional area of the exhaust flow path 102, and the minimum flow path cross-sectional area of the exhaust downstream end 108 is the exhaust flow. The maximum flow rate of the sub-flow path R2 is made smaller than the maximum flow rate of the main flow path R1 by making it smaller than the minimum flow path cross-sectional area of the path 102, but it is said that heat dissipation in the sub-flow path R2 is suppressed as much as possible. From the viewpoint, the maximum flow rate of the sub-flow path R2 is actually the main flow path because the flow path cross-sectional area of the detour flow path 109 is made smaller than the flow path cross-sectional area of the exhaust flow path 102 over the entire length of the detour flow path 109. It is desirable that the flow rate be smaller than the maximum flow rate of R1.

The heating device 110 is operated when there is a concern that the temperature of the SCR catalyst 105 will decrease due to the decrease in the exhaust temperature in order to reduce the power consumption as much as possible, and the temperature decrease of the SCR catalyst 105 due to the decrease in the exhaust temperature will occur. It is desirable to stop if there is no concern.

As described above, when there is no concern about the temperature decrease of the SCR catalyst 105 due to the decrease in the exhaust temperature, the valve body 106 is fully opened, and the exhaust gas flowing to the auxiliary flow path R2 is small, but even if it is small. Since the high-temperature exhaust also flows to the subchannel R2, the subchannel R2, the heating device 110, and the second PM collection filter 111 are preheated or kept warm even if the heating device 110 is stopped.

In other words, even if the heating device 110 is stopped, the sub-flow path R2, the heating device 110, and the second PM collection filter 111 are difficult to cool, so that the temperature of the exhaust gas flowing through the sub-flow path R2 is difficult to decrease, and the SCR catalyst is used. It is unlikely that the temperature of 105 will drop.

When the heating device 110 is operated again after the heating device 110 is stopped, the subchannel R2, the heating device 110, and the second PM collection filter 111 are preheated or kept warm while the heating device 110 is stopped. Therefore, the power supply time required for heating or maintaining the subchannel R2 and the second PM collection filter 111 to a predetermined temperature in the heating device 110 is shortened, and the power consumption can be reduced.

Since the second PM collection filter 111 only needs to be able to collect a small amount of PM in the exhaust gas flowing through the secondary flow path R2, it has a larger capacity (PM collection capacity) than the first PM collection filter 104. Is small.

Since the small capacity inevitably means that the volume is small and the heat capacity is also small, the power supply time required for heating or maintaining the second PM collection filter 111 at a predetermined temperature is shortened, and the power consumption is reduced. Can be done.

The PM collected by the second PM collection filter 111 is collected by the first PM collection filter 104 by, for example, high-temperature exhaust gas discharged under a high load state such that the valve body 106 is fully opened. It is burnt and removed together with PM.

As described above, in the exhaust aftertreatment device 100, the sub-flow path R2 is installed separately from the original main flow path R1, and most of the cases where there is a concern that the temperature of the SCR catalyst 105 will decrease due to the decrease in the exhaust temperature. The valve body 106 is controlled so that the exhaust gas from the sub-flow path R2 flows to the sub-flow path R2, and the exhaust gas flowing from the sub-flow path R2 flows to the SCR catalyst 105 after being heated by the heating device 110. It is possible to suppress the temperature drop of 105.

In particular, in the exhaust aftertreatment device 100, when there is a concern about a temperature drop of the SCR catalyst 105 due to a drop in the exhaust temperature, that is, before the exhaust temperature actually drops, the main flow path R1 is cut off. The temperature drop of the SCR catalyst 105 due to the drop in the exhaust temperature is more effectively suppressed than when the flow path in which the exhaust gas flows to the heating device and the flow path in which the exhaust gas does not flow to the heating device are switched based on the exhaust gas temperature. I can do things.

100 Exhaust aftertreatment device 101 Internal combustion engine 102 Exhaust flow path 103 Oxidation catalyst 104 First PM collection filter 105 SCR catalyst 106 Valve body 107 Exhaust upstream end 108 Exhaust downstream end 109 Bypass flow path 110 Heating device 111 Second PM collection filter 112 ECU
113 Engine speed sensor 114 Outside air temperature sensor 115 Accelerator opening sensor 116 Vehicle speed sensor 117 Foot brake sensor R1 Main flow path R2 Sub flow path

Claims (6)

Oxidation catalyst installed in the exhaust flow path of the internal combustion engine,
The first PM collection filter installed in the exhaust flow path and arranged on the exhaust downstream side of the oxidation catalyst,
With the SCR catalyst installed in the exhaust flow path and arranged on the exhaust downstream side of the first PM collection filter,
Equipped with
In the exhaust aftertreatment device that purifies the exhaust gas of the internal combustion engine,
A valve body installed in the exhaust flow path and arranged on the exhaust downstream side of the first PM collection filter and on the exhaust upstream side of the SCR catalyst.
A detour in which the exhaust upstream end is connected to the exhaust flow path on the exhaust upstream side of the oxidation catalyst and the exhaust downstream end is connected to the exhaust flow path on the exhaust downstream side of the valve body and on the exhaust upstream side of the SCR catalyst. Channel and
The heating device installed in the detour flow path and
A second PM collection filter installed in the detour flow path and arranged on the exhaust downstream side of the heating device,
Further prepare
The valve body is closed when there is a concern about a temperature drop of the SCR catalyst due to a decrease in the exhaust temperature, and is opened when there is no concern about a temperature decrease of the SCR catalyst due to a decrease in the exhaust temperature. Exhaust aftertreatment device. The exhaust aftertreatment device according to claim 1, wherein the detour flow path has a smaller maximum flow rate than the exhaust flow path. The exhaust aftertreatment device according to claim 1 or 2, wherein the second PM collection filter has a smaller capacity than the first PM collection filter. The heating device is operated when there is a concern about a temperature drop of the SCR catalyst due to a decrease in the exhaust temperature, and is stopped when there is no concern about a temperature decrease of the SCR catalyst due to a decrease in the exhaust temperature. The exhaust aftertreatment device according to any one of 1 to 3. When there is concern about a decrease in the temperature of the SCR catalyst due to a decrease in the exhaust temperature, the fuel injection amount of the internal combustion engine tends to decrease or no injection is performed when the vehicle equipped with the internal combustion engine is in a decelerated state. In some cases, when the vehicle is stopped and the internal combustion engine is idling, and there is no concern about a decrease in the temperature of the SCR catalyst due to a decrease in the exhaust temperature, the vehicle is in a non-deceleration state. The exhaust aftertreatment device according to any one of claims 1 to 4, wherein there is a case or the vehicle is in a non-stop state. It is assumed that the opening degree of the valve body is reduced when the temperature drop of the SCR catalyst is assumed to be large due to the decrease in the exhaust temperature, and the temperature decrease of the SCR catalyst due to the decrease in the exhaust temperature is small. The exhaust aftertreatment device according to any one of claims 1 to 5, wherein the opening degree is increased in such a case, and the SCR catalyst is fully opened when there is no concern about the temperature decrease of the SCR catalyst due to the decrease of the exhaust temperature.

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