JP2019035369A - Exhaust emission control device and vehicle having the same - Google Patents

Abstract

To provide an exhaust emission control device which can suitably control a temperature of an oxidation catalyst, and a vehicle having the same.SOLUTION: An exhaust emission control device 20 arranged in an exhaust passage 12 of a diesel engine 10 comprises: a DOC device (oxidation catalyst device) 30 which covers a casing 34 for encapsulating an oxidation catalyst 33, and has a heat protector 35 which is opened and closed by an opening/closing mechanism 31; and a control device 21 which controls the opening/closing mechanism 31 so as to open the heat protector 35 when a temperature of exhaust emission flowing into the oxidation catalyst 33 is a prescribed target temperature (for example, 300°C) or higher, and a PM-removing filter 40 arranged on a downstream side of the DOC device 30 is not in forcible regeneration processing, and also controls the opening/closing mechanism 31 so as to close the heat protector 35 when the filter 40 is in the forcible regeneration processing.SELECTED DRAWING: Figure 4B

Description

  The present disclosure relates to an exhaust purification device that purifies exhaust gas and a vehicle including the same.

Conventionally, as an exhaust purification device for purifying particulate matter (PM) in exhaust exhausted from a diesel engine, an exhaust purification device having a PM removal filter and an oxidation catalyst disposed on the upstream side of the filter Is known (see, for example, Patent Document 1). In such an exhaust purification apparatus, the oxidation catalyst promotes an oxidation reaction that changes nitrogen monoxide (NO) in the exhaust gas to nitrogen dioxide (NO ₂ ) by its oxidation catalytic action. With the nitrogen dioxide produced in this oxidation catalyst, PM deposited on the filter can be burned and discharged as carbon dioxide (CO ₂ ). Thereby, the filter can be regenerated.

  Further, conventionally, in order to forcibly regenerate the filter of the diesel engine, the temperature of the exhaust gas of the diesel engine is raised to a predetermined filter forced regeneration temperature (for example, 600 ° C.) or more by performing, for example, post injection, A filter forced regeneration process is also generally performed in which the PM of the filter is forcibly burned and removed.

JP, 2006-188579, A

  By the way, the oxidation catalyst can efficiently generate nitrogen dioxide at a predetermined temperature (for example, 300 ° C. to 400 ° C.) lower than the filter forced regeneration temperature as compared with other temperature zones. For this reason, if the temperature of the oxidation catalyst can be adjusted in the vicinity of such a predetermined temperature, nitrogen dioxide produced by the oxidation catalyst at a temperature lower than the filter forced regeneration temperature is effectively supplied to the filter, and is supplied to the filter. PM can be made difficult to deposit. As a result, the execution frequency of the forced regeneration process of the filter can be reduced, and fuel consumption can be reduced.

  An object of the present disclosure is to provide an exhaust purification device capable of suitably adjusting the temperature of an oxidation catalyst and a vehicle including the exhaust purification device.

  An exhaust purification device of the present disclosure is an exhaust purification device provided in an exhaust passage of a diesel engine, the oxidation catalyst device having a heat protector that covers a casing containing an oxidation catalyst and is opened and closed by an opening / closing mechanism, and the oxidation When the temperature of the exhaust gas flowing into the catalyst is equal to or higher than a predetermined target temperature and the PM removal filter provided on the downstream side of the oxidation catalyst device is not in the forced regeneration process, the heat protector is opened. And a control device that controls the open / close mechanism to close the heat protector when the filter is in a forced regeneration process.

  A vehicle according to the present disclosure includes the exhaust purification device.

  According to the present disclosure, the temperature of the oxidation catalyst can be suitably adjusted.

Configuration diagram schematically showing the configuration of a diesel engine system to which an exhaust emission control device is applied The figure for demonstrating the structure of a DOC apparatus. The figure which illustrated how a heat protector opened and closed The figure which illustrated how a heat protector opened and closed Diagram for explaining the mechanism for opening and closing the heat protector Diagram for explaining the mechanism for opening and closing the heat protector Flowchart for explaining exhaust gas temperature adjustment control by control device

  Hereinafter, each embodiment of the present disclosure will be described in detail with reference to the drawings. However, a more detailed description than necessary, for example, a detailed description of already well-known matters or a duplicate description of substantially the same configuration may be omitted.

  FIG. 1 is a configuration diagram schematically illustrating a configuration of a diesel engine system 1 to which an exhaust purification device 20 according to an embodiment of the present disclosure is applied. The diesel engine system 1 includes a diesel engine 10, an exhaust passage 12, and an exhaust purification device 20. The diesel engine 10 includes a plurality of cylinders 11 and a vacuum pump 14. In the present embodiment, the diesel engine system 1 is assumed to be mounted on a vehicle, particularly a large vehicle such as a truck or a bus.

  The exhaust passage 12 is a passage through which the exhaust discharged from the diesel engine 10 passes, and its upstream end is branched into a plurality of pipes and connected to the exhaust ports of the respective cylinders 11. The vacuum pump 14 creates a negative pressure in a negative pressure chamber 371 of an actuator 37 described later.

  The exhaust purification device 20 is disposed in the middle of the exhaust passage 12. The exhaust purification device 20 includes a control device 21, a DOC (Diesel Oxidation Catalyst) device 30, and a filter 40.

  The control device 21 includes a microcomputer having a CPU, a ROM, a RAM, and the like, and controls each component of the exhaust purification device 20. The control device 21 executes various processes such as an exhaust gas temperature adjusting process described later. In the present embodiment, the control device 21 is shown as a component of the exhaust purification device 20, but may be an ECU (Engine Control Unit) that controls the entire diesel engine system 1, for example.

  The filter 40 is a PM removal filter. The filter 40 is disposed downstream of the DOC device 30 in the exhaust flow direction. Specifically, the filter 40 removes the PM contained in the exhaust G by collecting PM contained in the exhaust G passing through the filter 40. A specific type of the filter 40 is not particularly limited. For example, a wall flow type diesel particulate filter may be used as the filter 40.

The DOC device 30 has a configuration in which a noble metal catalyst such as platinum (Pt) or palladium (Pd) is supported. The DOC device 30 promotes an oxidation reaction that changes nitrogen monoxide (NO) in the exhaust G to nitrogen dioxide (NO ₂ ) by the oxidation catalytic action of the noble metal catalyst. Nitrogen dioxide generated by the DOC device 30 burns PM deposited on the downstream filter 40 and discharges it as carbon dioxide (CO ₂ ). Thereby, the amount of PM deposited on the filter 40 is always reduced.

  As shown in FIG. 1, the DOC device 30 includes an opening / closing mechanism 31 and a DOC body 32. As shown in FIG. 2, the DOC body 32 includes an oxidation catalyst 33, a casing 34, and a heat protector 35. FIG. 2 is a diagram for explaining the configuration of the DOC device 30.

  As shown in FIG. 2, in the DOC main body 32, an oxidation catalyst 33 is included in a casing 34 made of metal (for example, a stainless material such as SUS304 having excellent heat resistance). As shown in FIG. 2, the first half (upstream side) portion of the casing 34 is formed in a substantially conical shape with the exhaust passage 12U connected to the apex portion, for example, and the second half (downstream side) portion is a bottom portion of the cone. It is formed in a substantially cylindrical shape having the same diameter. An oxidation catalyst 33 is encapsulated inside the latter half of the cylindrical shape. An exhaust passage 12D is connected to the rear half of the casing 34. In the following description, the upstream side of the DOC device 30 in the exhaust passage 12 may be referred to as the exhaust passage 12U, and the downstream side may be referred to as the exhaust passage 12D. With such a shape, the exhaust G flowing into the casing 34 from the exhaust passage 12U spreads along the side surface of the conical portion of the casing 34 and preferably contacts the oxidation catalyst 33. Thereby, nitrogen monoxide in the exhaust G is changed to nitrogen dioxide by the oxidation catalytic action of the oxidation catalyst 33. In this way, the exhaust G containing a large amount of nitrogen dioxide flows out from the exhaust passage 12D.

  A temperature sensor TS is provided near the inlet portion of the oxidation catalyst 33, that is, in the vicinity of the connection portion between the front half portion and the rear half portion of the casing 34. The temperature sensor TS is a thermistor provided so that the sensor portion protrudes into the casing 34, for example. The temperature sensor TS is connected to the control device 21, and the control device 21 can acquire the temperature of the exhaust G flowing into the oxidation catalyst 33 by the temperature sensor TS.

  The casing 34 is covered with a heat protector 35. The heat protector 35 is formed of a metal plate (for example, a stainless material such as SUS430 having excellent workability). As will be described later, the heat protector 35 is configured to be openable and closable. However, in the closed state, as shown in FIG. Shape combined with shape).

  The heat protector 35 keeps the oxidation catalyst 33 and the casing 34 warm, and protects an object (for example, a vehicle component on which the diesel engine system 1 is mounted) existing around the DOC device 30 from the heat of the exhaust G. It is a member provided in. That is, the exhaust gas G passing through the oxidation catalyst 33 and the oxidation catalyst 33 are kept warm by the heat protector 35, and the object existing around the DOC device 30 is protected from the radiant heat of the high-temperature oxidation catalyst 33.

  The heat protector 35 is configured to be opened and closed by an actuator 37 and a moving member 38 which will be described later. FIG. 3A and FIG. 3B are diagrams illustrating how the heat protector 35 opens and closes. 3A is a perspective view showing a state in which the heat protector 35 is closed, and FIG. 3B is a perspective view showing a state in which the heat protector 35 is opened. 3A and 3B, the opening / closing mechanism 31 is not shown.

  As shown in FIGS. 3A and 3B, the heat protector 35 includes a plurality of heat protector pieces 351. Each of the plurality of heat protector pieces 351 has the same shape, and the heat protector 35 is configured by arranging the plurality of heat protector pieces 351 circumferentially without a gap so as to be adjacent to each other in the closed state. . As described above, the heat protector 35 is configured by arranging the plurality of heat protector pieces 351 without any gaps, so that the casing 34 housed in the heat protector 35 is exposed to the outside air when the heat protector 35 is closed. There is no touch.

  As shown in FIG. 3B, each of the heat protector pieces 351 is fixed to the casing 34 so as to be rotatable by a hinge member 352 at the rearmost part (most downstream side). That is, each of the plurality of heat protector pieces 351 opens and closes with the hinge member 352 as a fulcrum. FIG. 3B shows a state in which only the heat protector piece 351 on the front side of the paper is opened, but in reality, the heat protector piece 351 is also present on the back side of the paper and is opened similarly to the front side. Become.

  4A and 4B are diagrams for explaining a mechanism for opening and closing the heat protector 35. FIG. 4A and 4B, a cross-sectional view of the DOC device 30 is shown as in FIG. 4A is a schematic cross-sectional view showing a state in which the heat protector 35 is closed, and FIG. 4B is a schematic cross-sectional view showing a state in which the heat protector 35 is opened. 4A and 4B, the temperature sensor TS and the hinge member 352 are not shown.

  The opening / closing mechanism 31 shown in FIG. 2 includes the opening / closing valve 36, actuator 37, negative pressure chamber 371, driving member 372, moving member 38, and connecting member 39 shown in FIGS. 4A and 4B.

  The open / close valve 36 is a valve such as a VSV (Vacuum Switching Valve), for example, and switches the connection destination of the negative pressure chamber 371 of the actuator 37 between the atmosphere and the vacuum pump 14 based on the control of the control device 21.

  The actuator 37 is, for example, a negative pressure diaphragm and has a negative pressure chamber 371, and the driving member 372 is driven by the negative pressure chamber 371 becoming negative pressure by the vacuum pump 14. The direction in which the actuator 37 drives the drive member 372 is the left-right direction in FIGS. 4A and 4B, that is, the direction parallel to the exhaust passage 12. When the negative pressure chamber 371 becomes negative pressure, the actuator 37 drives the drive member 372 toward the downstream side (the right direction in FIGS. 4A and 4B) (corresponding to FIG. 4B). On the other hand, when the negative pressure chamber 371 reaches atmospheric pressure, the actuator 37 drives the drive member 372 toward the upstream side (the left direction in FIGS. 4A and 4B) (corresponding to FIG. 4A). Note that a range in which the drive member 372 can be driven by the actuator 37 (hereinafter referred to as a drivable range) is determined in advance, and FIG. 4A shows a state in which the drive member 372 is driven to the most upstream side in the drivable range. 4B corresponds to the state in which the drive member 372 is driven to the most downstream side in the driveable range.

  A moving member 38 is connected to the end of the driving member 372 opposite to the actuator 37. When the driving member 372 is driven toward the upstream side or the downstream side by the actuator 37, the moving member 38 also moves toward the upstream side or the downstream side. That is, the moving member 38 moves in parallel with respect to the exhaust passage 12 and the casing 34.

  Although only a part is shown in FIGS. 4A and 4B, the moving member 38 and each of the heat protector pieces 351 of the heat protector 35 are connected via a plurality of connecting members 39, and each heat protector piece 351. Is opened and closed as the moving member 38 moves. The moving member 38 has, for example, a cylindrical shape whose diameter is larger than the closed state of the heat protector 35, and the exhaust passage 12 is disposed inside the cylinder. Although not shown in FIGS. 4A and 4B, when the moving member 38 moves upstream, the heat protector 35 may exist inside the cylinder, or when the moving member moves downstream, The filter 40 may exist inside the cylinder.

  The above is summarized as follows. When the opening / closing valve 36 is switched to the atmospheric side by the control device 21, the inside of the negative pressure chamber 371 of the actuator 37 becomes atmospheric pressure, and the driving member 372 and the moving member 38 are moved to the most upstream side in the drivable range. In this state, each heat protector piece 351 is not subjected to the pulling force by the connecting member 39, and the heat protector 35 is closed as shown in FIG. 4A. On the other hand, when the open / close valve 36 is switched to the vacuum pump 14 side, the negative pressure chamber 371 of the actuator 37 becomes negative pressure, and the driving member 372 and the moving member 38 are moved to the most downstream side in the drivable range. In this state, each heat protector piece 351 receives a pulling force by the connecting member 39, and the heat protector 35 opens as shown in FIG. 4B.

  In this way, the control device 21 switches the opening / closing valve 36 so that the heat protector 35 is opened / closed. 4A and 4B, for the sake of simplicity, only the opening and closing of some of the heat protector pieces 351 is illustrated. However, actually, as shown in FIGS. 3A and 3B, all of the heat protector pieces 351 are opened and closed. Done at the same time.

  When the heat protector 35 is opened, the casing 34 is exposed to the outside air. In the state where the casing 34 is exposed to the outside air, the heat dissipation rate from the surface of the casing 34 is significantly increased compared to the state where the casing 34 is not exposed (the state where the heat protector 35 is closed), and the oxidation contained in the casing 34. The temperatures of the exhaust G passing through the catalyst 33 and the oxidation catalyst 33 are reduced. In the present embodiment, the heat protector 35 is configured to open toward the upstream side as shown in FIG. 4B. The upstream side of the exhaust passage 12 generally corresponds to the front of the vehicle. This is because the traveling wind due to traveling of the vehicle tends to flow into the heat protector 35 in an open state.

  Thus, the control device 21 can adjust the temperatures of the exhaust gas G passing through the oxidation catalyst 33 and the oxidation catalyst 33 by opening and closing the heat protector 35 by controlling the open / close mechanism 31. Below, the detail of the temperature adjustment control of the exhaust G by the control apparatus 21 is demonstrated.

  FIG. 5 is a flowchart for explaining the exhaust gas temperature adjustment control by the control device 21.

  In step S1, the control device 21 determines whether or not the vehicle on which the diesel engine system 1 is mounted is traveling. Whether or not the vehicle is traveling is determined by, for example, the control device 21 monitoring the speed sensor of the vehicle and determining that the vehicle is traveling when the current speed is not 0, and is not traveling when the current speed is 0. Can be determined. Alternatively, the reference value for determining whether or not the control device 21 is traveling may be a predetermined speed other than 0 (for example, 5 km / h). In this case, the control device 21 may determine that the vehicle is traveling when the current speed is equal to or higher than the predetermined speed, and may determine that the vehicle is not traveling when the current speed is less than the predetermined speed.

  When it determines with driving | running | working in step S1 (step S1: YES), the control apparatus 21 advances a process to step S2, and when that is not right (step S1: NO), it advances to step S5.

  Next, in step S2, the control device 21 monitors the temperature of the exhaust G flowing into the oxidation catalyst 33, and determines whether or not the temperature is a predetermined target temperature, for example, 300 ° C. or higher. The temperature of the exhaust G monitored by the control device 21 is acquired by the temperature sensor TS.

  Note that the predetermined target temperature that serves as a reference for the determination in step S2 is a value determined based on a temperature (generally 300 ° C. to 400 ° C.) at which nitrogen dioxide can be efficiently generated in the oxidation catalyst. Although the target temperature is set to 300 ° C. in the present embodiment, the present disclosure is not limited to this, and the target temperature may be appropriately set between 300 ° C. and 400 ° C.

  When it determines with exhaust G being 300 degreeC or more in step S2 (step S2: YES), the control apparatus 21 advances a process to step S3, and when that is not right (step S2: NO), a process is advanced to step S5.

  In step S3, the control device 21 determines whether or not the filter 40 is in the forced regeneration process. The forced regeneration process of the filter 40 is a process of preventing or eliminating clogging of the filter 40 by burning the PM collected by the filter 40 by setting the exhaust G to a high temperature (for example, 600 ° C. or more). The control device 21 executes post-injection control for injecting fuel to the cylinders 11 at a time after the main injection, forcing the filter 40 by forcibly raising the temperature of the exhaust G. Perform playback processing.

  In step S3, when the forced regeneration process of the filter 40 is being executed (step S3: YES), the control device 21 advances the process to step S5. Otherwise (step S3: NO), the process advances to step S4. .

  The above is summarized as follows. When the vehicle equipped with the diesel engine system 1 is traveling, the temperature of the exhaust gas G flowing into the oxidation catalyst 33 is not less than the target temperature of 300 ° C., and the filter 40 is not being forcedly regenerated. Advances to step S4. On the other hand, when the vehicle is not traveling, or the temperature of the exhaust gas G flowing into the oxidation catalyst 33 is less than 300 ° C. or the filter 40 is being forcibly regenerated, the control device 21 advances the process to step S5.

  When the vehicle equipped with the diesel engine system 1 is traveling, the temperature of the exhaust gas G flowing into the oxidation catalyst 33 is not less than 300 ° C., and the forced regeneration process of the filter 40 is not being performed, in step S4, the control device 21 opens and closes the opening / closing mechanism. 31 is controlled to open the heat protector 35. Then, as described above, the traveling wind blows through the gap between the opened heat protectors 35, and the temperature of the exhaust gas G flowing into the oxidation catalyst 33 through the casing 34 is gradually reduced.

  When the vehicle is not running, or when the temperature of the exhaust gas G flowing into the oxidation catalyst 33 is less than 300 ° C. or when the filter 40 is being forcedly regenerated, the control device 21 opens and closes in step S5. The mechanism is controlled to close the heat protector 35. Then, since the casing 34 is not directly exposed to the outside air, the temperature of the exhaust G of the exhaust G flowing into the oxidation catalyst 33 gradually increases.

  In the exhaust gas temperature adjustment control shown in FIG. 5, the determination is made using the temperature of the exhaust gas G flowing into the oxidation catalyst 33. In the present disclosure, this is the temperature of the exhaust gas G flowing into the oxidation catalyst 33. This is because it is considered that the temperature of the exhaust gas G passing through the oxidation catalyst 33 and, consequently, the temperature of the oxidation catalyst 33 are substantially equal.

  Although not shown in FIG. 5, the temperature adjustment control in steps S <b> 1 to S <b> 5 is repeated every predetermined time (for example, with a span of about several milliseconds to several seconds). By such control, the temperature of the exhaust gas G flowing into the oxidation catalyst 33 is kept near the target temperature when the vehicle is traveling and the filter 40 is not being forcedly regenerated. Thereby, the temperature of the oxidation catalyst 33 is also kept near the target temperature, and nitrogen dioxide is efficiently generated in the oxidation catalyst 33. As a result, the amount of PM deposited on the filter 40 can be reduced as compared with the case where the temperature adjustment control of the exhaust G is not performed. For this reason, since the execution frequency of the forced regeneration process of the filter 40 can be reduced, the fuel consumption reduction in the diesel engine system 1 can be aimed at.

  And since the heat protector 35 is closed during the forced regeneration process of the filter 4, the temperature of the exhaust gas G can be suitably raised by post injection. For this reason, the forced regeneration process of the filter 40 can be performed efficiently.

  In addition, when the vehicle is not running, that is, for example, during a temporary stop such as waiting for a signal or a railroad crossing, when stopping on a road shoulder, or while parking in a parking lot or the like, the temperature of the exhaust G flowing into the oxidation catalyst 33 and the filter Regardless of whether the forced regeneration process is being performed, the heat protector 35 is closed. In such a case, the diesel engine 10 is stopped or kept at a low rotation speed such as idling rotation, so that the temperature of the exhaust gas G flowing into the oxidation catalyst 33 gradually decreases. As a result, it is possible to prevent a situation in which a great deal of heat is released from a vehicle that is not running and a danger is caused to things around the vehicle.

<Action and effect>
As described above, the exhaust purification device 20 according to the embodiment of the present disclosure is the exhaust purification device 20 provided in the exhaust passage 12 of the diesel engine 10 and covers the casing 34 that contains the oxidation catalyst 33. The DOC device (oxidation catalyst device) 30 having the heat protector 35 opened and closed by the opening / closing mechanism 31 and the temperature of the exhaust gas G flowing into the oxidation catalyst 33 are equal to or higher than a predetermined target temperature (for example, 300 ° C.), and the DOC device 30 when the PM removal filter 40 provided on the downstream side of 30 is not in the forced regeneration process, the opening / closing mechanism 31 is controlled to open the heat protector 35, and when the filter 40 is in the forced regeneration process, And a control device 21 that controls the opening / closing mechanism 31 so as to close the heat protector 35.

  With such a configuration, the temperature of the exhaust gas G flowing into the oxidation catalyst 33 is kept in the vicinity of the target temperature, which is the temperature at which nitrogen dioxide is efficiently generated in the oxidation catalyst 33, when the filter 40 is not in the forced regeneration process. It is. Thereby, compared with the case where the temperature adjustment control of the exhaust G is not performed, nitrogen dioxide is efficiently generated in the oxidation catalyst 33. Therefore, PM is suitably removed in the filter 40, and the amount of PM deposited on the filter 40 is reduced. Can be reduced. For this reason, since the execution frequency of the forced regeneration process of the filter 40 can be reduced, the frequency | count of the post injection for a forced regeneration process can be reduced, and the fuel consumption reduction in the diesel engine system 1 can be aimed at.

  Further, when the filter 40 is being forcibly regenerated, the heat protector 35 is closed regardless of the temperature of the exhaust gas G flowing into the oxidation catalyst 33, so that the temperature of the exhaust gas G can be suitably increased by post injection. it can. As a result, the temperature of the exhaust G quickly rises to a temperature suitable for the forced regeneration process (600 ° C.), so that the forced regeneration process of the filter 40 can be performed efficiently.

  On the other hand, in the exhaust purification device 20 according to the embodiment of the present disclosure, the control device 21 determines whether or not the vehicle is traveling, and flows into the oxidation catalyst 33 when it is determined that the vehicle is not traveling. Regardless of the temperature of the exhaust G and whether or not the forced filter regeneration process is being performed, the open / close mechanism 31 is controlled to close the heat protector 35.

  With such a configuration, when the vehicle is not running, that is, for example, during a temporary stop such as waiting for a signal or a railroad crossing, stopping on a road shoulder, parking in a parking lot, etc., the temperature of the exhaust G is a predetermined target. The heat protector 35 is closed regardless of whether the temperature is higher than the temperature and whether the filter forced regeneration process is being performed. In such a case, the diesel engine 10 is stopped or kept at a relatively low rotational speed such as idling rotation, so that the temperature of the exhaust G gradually decreases. As a result, it is possible to prevent a situation in which a great deal of heat is released from a vehicle that is not running and a danger is caused to things around the vehicle.

  While various embodiments have been described with reference to the drawings, the present disclosure is not limited to such examples. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the scope of the disclosure. Understood. In addition, the constituent elements in the above embodiments may be arbitrarily combined without departing from the spirit of the disclosure.

  In the embodiment described above, the method of performing the post injection as the method of the forced regeneration processing of the filter 40 has been described, but the present disclosure is not limited to this. As another example, for example, an exhaust pipe injector for injecting fuel into the exhaust gas is provided on the upstream side of the filter 40 in the exhaust passage 12, and the control apparatus 21 filters the exhaust temperature by injecting fuel from the exhaust pipe injector. You may employ | adopt the method made to raise more than forced regeneration temperature.

  In the embodiment described above, the example in which the heat protector 35 opens toward the upstream side of the exhaust passage 12, that is, toward the front of the vehicle has been described. However, the present disclosure is not limited to this, and the heat protector 35 may be opened in another direction such as the rear or side direction of the vehicle.

  Further, in the above-described embodiment, the determination is performed using the temperature of the exhaust G flowing into the oxidation catalyst 33 in the exhaust gas temperature adjusting process, but the present disclosure is not limited to this. For example, the temperature of the oxidation catalyst 33 may be acquired by direct measurement or estimation, and the exhaust gas temperature adjustment process may be performed using the temperature. Examples of the method for obtaining the temperature of the oxidation catalyst 33 include a method for estimating the temperature of the oxidation catalyst 33 based on the difference between the exhaust temperature at the inlet of the oxidation catalyst 33 and the exhaust temperature at the outlet.

  The present disclosure is useful for an exhaust purification device that purifies exhaust gas.

DESCRIPTION OF SYMBOLS 1 Diesel engine system 10 Diesel engine 11 Cylinder 12 Exhaust passage 12D Exhaust passage 12U Exhaust passage 14 Vacuum pump 20 Exhaust purification device 21 Control device 30 DOC device 31 Opening / closing mechanism 32 DOC body 33 Oxidation catalyst 34 Casing 35 Heat protector 351 Heat protector piece 352 Hinge member 36 Open / close valve 37 Actuator 371 Negative pressure chamber 372 Drive member 38 Moving member 39 Connecting member TS Temperature sensor 40 Filter

Claims (4)

An exhaust purification device provided in an exhaust passage of a diesel engine,
An oxidation catalyst device having a heat protector that covers the casing containing the oxidation catalyst and is opened and closed by an opening and closing mechanism;
When the temperature of the exhaust gas flowing into the oxidation catalyst is equal to or higher than a predetermined target temperature and the PM removal filter provided on the downstream side of the oxidation catalyst device is not in the forced regeneration process, the heat protector is A control device that controls the open / close mechanism to close the heat protector when the open / close mechanism is controlled to open and the filter is in a forced regeneration process;
An exhaust emission control device. The control device determines whether or not the vehicle on which the diesel engine is mounted is traveling, and if it is determined that the vehicle is not traveling, whether or not the exhaust temperature and the filter forced regeneration processing are performed. Regardless of whether to control the opening and closing mechanism to close the heat protector,
The exhaust emission control device according to claim 1. The exhaust emission control device according to claim 1 or 2,
vehicle. An exhaust purification device provided in an exhaust passage of a diesel engine,
An oxidation catalyst device having a heat protector that covers the casing containing the oxidation catalyst and is opened and closed by an opening and closing mechanism;
When the temperature of the oxidation catalyst is equal to or higher than a predetermined target temperature and the PM removal filter provided on the downstream side of the oxidation catalyst device is not in the forced regeneration process, the heat protector is opened to open the heat protector. A control device that controls the opening and closing mechanism, and controls the opening and closing mechanism to close the heat protector when the filter is in the forced regeneration process;
An exhaust emission control device.

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