JP2019157828A - Vehicle heat shield structure - Google Patents

Abstract

To cool an exhaust emission control device as necessary.SOLUTION: According to one embodiment of the disclosure, a heat shield structure of a vehicle V is provided that is characterized by including: an exhaust emission control device 1 which purifies exhaust gas; and a heat shield plate 21 covering the exhaust emission control device from the outer side and having a movable part 22 which can open or close.SELECTED DRAWING: Figure 4

Description

  The present disclosure relates to a heat shield structure of a vehicle, and more particularly, to a heat shield structure including a heat shield plate that covers an exhaust purification device from the outside.

  In a vehicle equipped with an internal combustion engine, exhaust gas discharged from a combustion chamber of the internal combustion engine is discharged into the atmosphere after passing through an exhaust pipe. In the course of flowing through the exhaust pipe, it passes through an exhaust purification device including a catalyst and the like, and harmful components are removed or reduced.

  The exhaust purification device may become hot, and there is a risk of burns if a person touches it. For this reason, a heat shield that covers the exhaust purification device from the outside is provided to prevent people from touching the exhaust purification device.

Japanese Patent Laid-Open No. 2006-78609 JP 2013-18325 A JP 2011-230638 A

  However, since the conventional heat shield is merely a plate material, it is difficult to satisfy the request when it is desired to cool the exhaust purification device.

  Therefore, the present disclosure has been made in view of such circumstances, and an object thereof is to provide a heat shield structure for a vehicle that can cool an exhaust purification device as necessary.

According to one aspect of the present disclosure,
An exhaust purification device for purifying exhaust gas;
A heat shield plate that covers the exhaust purification device from the outside and has a movable part that can be opened and closed;
A heat shield structure for a vehicle is provided.

  Preferably, an electric device is attached to the exhaust gas purification apparatus, and the movable part is disposed in the vicinity of the electric device.

  Preferably, the movable part includes at least one of a door and a louver.

  Preferably, the heat shield structure further includes an actuator that opens and closes the movable part, and a control unit configured to control the actuator according to an operation state of the vehicle.

  According to the present disclosure, the exhaust purification device can be cooled as necessary.

It is a right view which shows the vehicle before attachment of a heat shield. It is a perspective view of an exhaust emission control device. It is a front view of an exhaust emission control device. It is a right view which shows the vehicle after the installation of a heat shield. It is a right view which expands and shows the heat shield board vicinity. It is a block diagram of a control apparatus. It is a right view which expands and shows the heat shield board vicinity of a 1st modification. FIG. 8 is a schematic plan view when FIG. 7 is viewed from above. It is a right view which expands and shows the heat shield board vicinity of a 2nd modification. FIG. 10 is a schematic rear view when FIG. 9 is viewed from the rear. It is a right view which expands and shows the heat shield board vicinity of a 3rd modification.

  Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. It should be noted that the present disclosure is not limited to the following embodiments.

  The heat insulation structure for a vehicle according to the present embodiment is applied to a large vehicle V as shown in FIG. 1, specifically, a truck. An internal combustion engine (also referred to as an engine) E as a power source mounted on the vehicle V is a diesel engine. However, the types and applications of the vehicle and the internal combustion engine are not limited. For example, the vehicle may be a small vehicle such as a passenger car, and the engine may be a gasoline engine. Each direction of three orthogonal axes (front / rear / left / right / up / down) of the vehicle V is indicated by arrows.

  The exhaust system of the vehicle V includes an exhaust manifold (not shown) connected to the engine E, an exhaust pipe (not shown) connected to the downstream side of the exhaust manifold, and an exhaust connected to the downstream side of the exhaust pipe. A purification device 1 and an outlet pipe (not shown) connected to the downstream side of the exhaust purification device 1 are provided. As will be described in detail later, the exhaust purification device 1 includes a plurality of catalysts and the like inside the casing 2 to remove or reduce harmful components in the exhaust. The exhaust gas after purification is discharged into the atmosphere from the outlet pipe.

  The exhaust emission control device 1 will be described with reference to FIGS. In addition, each direction of the exhaust emission control device 1 is defined so as to coincide with each direction of the vehicle V. However, it should be noted that this definition is merely for convenience.

  The exhaust purification device 1 includes a sealed box type casing 2 that accommodates a plurality of catalysts in a compact manner. The casing 2 is provided with a device inlet pipe 3 and a device outlet pipe (not shown). The aforementioned exhaust pipe is flange-connected to the apparatus inlet pipe 3, and the aforementioned outlet pipe is flange-connected to the apparatus outlet pipe.

  A sensor mounting recess 5 is provided at the right end of the front surface of the casing 2, and a sensor insertion hole 6 is provided in the bottom surface of the sensor mounting recess 5. A sensor indicated by an imaginary line, in this embodiment, a NOx sensor 7 is fixedly attached to the bottom surface portion of the sensor mounting recess 5 with its tip detection portion inserted into the sensor insertion hole 6. In the mounted state, the NOx sensor 7 is accommodated in the sensor mounting recess 5 in an obliquely upward state. The NOx sensor 7 is a sensor for detecting the NOx concentration of the exhaust gas.

  An injection valve mounting recess 8 is provided in the upper front corner of the left side surface portion 19 of the casing 2, and an injection valve insertion hole 9 is provided in the bottom surface of the injection valve mounting recess 8. The injection valve indicated by the phantom line, in this embodiment, the urea water injection valve (hereinafter simply referred to as the injection valve) 10 for injecting urea water is inserted into the injection valve insertion hole 9 at the tip portion having the injection hole, It is fixedly attached to the bottom surface of the injection valve mounting recess 8. In the mounted state, the injection valve 10 is disposed along the left-right direction with the injection hole directed to the right side, and the tip portion thereof is accommodated in the injection valve mounting recess 8.

  Although not shown, an exhaust passage partitioned by a metal tube and a metal plate is formed inside the casing 2. The exhaust passage has a shape that folds back and forth in the left-right direction. In the exhaust passage, four aftertreatment members, that is, a first oxidation catalyst, a filter, a selective reduction type NOx catalyst, and a second oxidation catalyst are arranged in order from the upstream side.

  The first oxidation catalyst oxidizes and purifies unburned components (hydrocarbon HC and carbon monoxide CO) in the exhaust gas, and heats the exhaust gas with the heat of reaction at this time. The filter is a so-called diesel particulate filter (DPF) or soot filter with catalyst (CSF: Catalyzed Soot Filter), and is a continuous regenerative filter carrying a catalyst. The filter is of a wall flow type, and collects particulate matter (hereinafter referred to as PM: Particulate Matter) contained in the exhaust gas, and continuously oxidizes the collected PM by catalytic reaction to remove it by combustion.

  The selective reduction type NOx catalyst (SCR: Selective Catalytic Reduction) reduces and removes NOx in exhaust gas using ammonia derived from urea water injected from the injection valve 10 as a reducing agent. The second oxidation catalyst is also referred to as an ammonia slip oxidation catalyst, and oxidizes and removes excess ammonia discharged (slipped) from the NOx catalyst. The injection valve 10 injects urea water at a position downstream of the filter and upstream of the NOx catalyst. The NOx sensor 7 detects the NOx concentration at a position downstream of the filter and upstream of the injection valve 10.

  The upstream end of the exhaust passage in the casing is connected to the apparatus inlet pipe 3, and the downstream end of the exhaust path in the casing is connected to the apparatus outlet pipe. The exhaust gas flowing into the apparatus inlet pipe 3 then flows through the exhaust passage in the casing 2 and passes through the four post-processing members in the process to be purified. Thereafter, the exhaust gas is discharged to the atmosphere through the apparatus outlet pipe and the outlet pipe.

  As shown in FIG. 1, the exhaust purification device 1 is attached to the right side of the vehicle V in this embodiment. Specifically, the exhaust purification device 1 is attached to the vehicle right side of the ladder-type chassis frame 13 of the vehicle V and at the vehicle rear side of the right front wheel 14. As is well known, an engine E is mounted below the cab 15 and between the left and right side frames, and the exhaust emission control device 1 is attached to a position behind the engine E in the vehicle. A fan F that is driven by a crankshaft and sends air backward is provided in front of the engine E, and a radiator R is disposed in front of the fan F.

  Now, in this vehicle V, the temperature of the exhaust emission control device 1 becomes extremely high during full load or high load operation of the vehicle V. For this reason, there is a risk of burns when a person touches the exhaust purification device 1. In particular, the exhaust emission control device 1 is provided at a height position where a pedestrian can contact. For this reason, if the pedestrian touches the exhaust purification device 1 when the vehicle V is stopped (for example, when the vehicle is idling) and the exhaust purification device 1 is at a high temperature, the pedestrian may be burned.

  Therefore, in the vehicle V of the present embodiment, as shown in FIG. 4, a heat shield 21 that covers the exhaust purification device 1 from the outside is provided so that pedestrians do not touch the exhaust purification device 1 in particular. The heat shield 21 is also referred to as a heat protector, and covers the entire exhaust gas purification apparatus 1 with a gap from the outside in the vehicle width direction, that is, from the right side. Although the heat shield plate 21 in the illustrated example has a quadrangular shape, its shape can be arbitrarily changed. The heat shield plate 21 is preferably made of a metal material, for example, preferably made of stainless steel. 1 shows the vehicle V before the heat shield plate 21 is attached, and FIG. 4 shows the vehicle V after the heat shield plate 21 is attached.

  However, since the conventional heat shield is a simple plate that does not change its shape, it is difficult to satisfy the request when it is desired to cool the exhaust purification device.

  Specifically, in the case of this embodiment, an injection valve 10 and an NOx sensor 7 as electrical devices are attached to the exhaust gas purification apparatus 1. At the time of full load or high load operation of the vehicle, the temperature of the exhaust emission control device 1 becomes extremely high, so that the injection valve 10 and the NOx sensor 7 become thermally severe and cooling of them is required. Conventionally, it is difficult to introduce the traveling wind inside the heat shield plate (exhaust gas purification device side), and it is difficult to discharge hot air trapped inside the heat shield plate. For this reason, it is difficult to cool the electric device, and the electric device may be damaged by heat damage.

  Therefore, in the present embodiment, as shown in FIGS. 4 and 5, a movable portion 22 that can be opened and closed is provided on the heat shield plate 21, and the exhaust purification device 1 can be actively cooled by opening the movable portion 22. .

  Specifically, the heat shield plate 21 includes a main body portion 23 whose position is fixed with respect to the vehicle V, and a movable portion 22 that is movable with respect to the main body portion 23 and can be opened and closed. In the case of the illustrated example, the movable portion 22 is formed by a door 24 and opens and closes in a laterally open manner by rotating around the vertical axis 25. 4 shows a closed state of the movable part 22, and FIG. 5 shows an open state of the movable part 22. A rear end 22 </ b> A of the movable part 22 is pivotally connected to the main body part 23 by a vertical axis 25. When the movable portion 22 is in the open state, the front end 22B of the movable portion 22 is positioned on the right side, that is, on the outside in the vehicle width direction, from the rear end 22A. When the movable portion 22 is in the closed state, the front end 22B of the movable portion 22 is positioned at the same position in the vehicle width direction as the rear end 22A.

  The heat shield 21 has a movable part 22 in a part thereof, in other words, only a part of the heat shield 21 is the movable part 22. In this embodiment, the movable part 22 is arrange | positioned in the vicinity of the injection valve 10 and the NOx sensor 7 which are electric devices. Specifically, only the upper corner portion of the heat shield 21 located in the vicinity of the injection valve 10 and the NOx sensor 7 is the movable portion 22.

  According to such a configuration, when the vehicle V is stopped (for example, when the vehicle is idle), the movable portion 22 is closed to prevent the pedestrian from touching the exhaust purification device 1 and being burned like the conventional heat shield plate. it can. Further, when the vehicle V is traveling and when the exhaust purification apparatus 1 is at a high temperature, such as during full load or high load operation of the vehicle V, the movable portion 22 is opened, so that the traveling wind W is applied to the heat shield plate 21 as shown in FIG. While being introduced into the inner side (exhaust gas purification device 1 side), hot air trapped inside the heat shield plate 21 can be discharged to actively cool the exhaust gas purification device 1. Therefore, the exhaust emission control device 1 can be cooled as necessary. In addition, it is possible to achieve both prevention of contact of the pedestrian with the exhaust purification device 1 and prevention of damage due to heat damage of the exhaust purification device 1.

  In particular, since the movable part 22 is disposed in the vicinity of the electrical devices such as the injection valve 10 and the NOx sensor 7, the movable part 22 is opened at the time of full load or high load operation of the vehicle V where the electrical devices become thermally severe. Thus, the traveling wind W can be positively applied to the electric device, and the electric device can be actively cooled. Therefore, damage due to heat damage of the electric device can be reliably suppressed. On the other hand, since the part other than the movable part 22 of the heat shield plate 21 (the part of the main body part 23) is still closed, the overcooling of the exhaust purification device 1 in the vicinity thereof is suppressed, and the activity of the catalyst or the like is suppressed. The state can be advantageously maintained. In short, only the part that needs to be cooled when the movable part 22 is opened is cooled, and the part that does not need to be cooled can be suppressed, so that the cooling can be performed efficiently.

  By the way, the opening and closing of the movable portion 22 is automatically performed according to the driving state of the vehicle V. That is, as shown in FIG. 6, the heat shield structure of the present embodiment includes an actuator 31 that opens and closes the movable portion 22, and a control unit and circuit that are configured to control the actuator 31 according to the driving state of the vehicle V. It further includes an electronic control unit (referred to as ECU) 100 as a circuit or a controller. The driving state of the vehicle V is detected by each sensor to be described later, and the ECU 100 controls the actuator 31 based on the output of each sensor, thereby controlling the opening degree of the movable portion 22.

  The ECU 100 is connected to an exhaust temperature sensor 32 that detects the exhaust temperature, an outside air temperature sensor 33 that detects the outside air temperature, a load sensor 34 that detects the engine load, and a vehicle speed sensor 35 that detects the vehicle speed. The ECU 100 controls the actuator 31 based on at least one of the exhaust temperature, the outside air temperature, the engine load, and the vehicle speed detected by these sensors. The engine load may be substituted by the accelerator opening or the fuel injection amount.

  In addition to this, the ECU 100 executes known regeneration control in order to regenerate the filter inside the exhaust purification device 1. During execution of this regeneration control, exhaust pipe injection and post injection are executed, the exhaust temperature rises, and the exhaust purification device 1 becomes high temperature. If this happens, there is a concern about heat damage, and thus the ECU 100 controls the actuator 31 depending on whether or not regeneration control is executed.

  As a tendency, the actuator 31 is controlled so that the opening degree of the movable part 22 increases as the exhaust gas temperature increases. This is because the higher the exhaust gas temperature, the higher the temperature of the exhaust gas purification device 1, and the more the cooling amount needs to be increased. For the same reason, the actuator 31 is controlled so that the opening degree of the movable portion 22 increases as the outside air temperature increases.

  The actuator 31 is controlled so that the opening degree of the movable portion 22 increases as the engine load increases. This is because the higher the engine load, the higher the exhaust temperature, the higher the temperature of the exhaust emission control device 1, and the greater the amount of cooling.

  Regarding the vehicle speed, the actuator 31 is controlled so that the movable portion 22 is unconditionally closed when the vehicle speed is zero. This is to prevent a pedestrian from contacting the exhaust purification device 1. On the other hand, when the vehicle speed is greater than zero, for example, the actuator 31 can be controlled so that the opening degree of the movable portion 22 decreases as the vehicle speed increases. This is because the higher the vehicle speed, the greater the traveling air volume and the less need to open the movable part 22.

  During the execution of the regeneration control, the actuator 31 is controlled so that the movable portion 22 is opened. This is because the exhaust gas temperature rises and the exhaust gas purification device 1 becomes hot during the regeneration control. However, even when regeneration control is being executed, the movable portion 22 is closed when the vehicle is stopped (when the vehicle speed is zero).

  Thus, by controlling the opening degree of the movable portion 22 according to the driving state of the vehicle V, the exhaust purification device 1 can be cooled more efficiently.

  Next, some modified examples of this embodiment will be described. In addition, the same code | symbol is attached | subjected in the figure to the part similar to the above-mentioned basic embodiment, and description is omitted, and below, a difference with basic embodiment is mainly demonstrated.

(First modification)
In the first modification shown in FIG. 7, the heat shield plate 21 has a movable portion 22 in its entirety, in other words, the entire heat shield plate 21 is substantially the movable portion 22. Specifically, the heat shield plate 21 includes a frame body 41 whose position is fixed with respect to the vehicle V, and a movable portion 22 that is movable with respect to the frame body 41 and that can be opened and closed. FIG. 7 shows the open state of the movable portion 22. In the illustrated example, the movable portion 22 is formed by a louver 42.

  8 is a schematic plan view when FIG. 7 is viewed from above except for the frame body 41, in which (A) is in a closed state and (B) is in an open state. “Inside” and “outside” mean the inside in the vehicle width direction (exhaust purification device 1 side) and the outside (outside side), respectively.

  As shown in FIGS. 7 and 8, the louver 42 includes a plurality of blades 44 that open and close in a laterally open manner by rotating around the longitudinal axis 43. A rear end 44 </ b> A of the slat 44 is pivotally connected to the frame body 41 by a vertical axis 43. An operation part 45 is provided at the front end 44B of the slat 44, and the operation part 45 of each slat 44 is connected by a connecting strip 46. As shown in FIG. 8 (B), when the connecting strip 46 is pulled rearward as indicated by the arrow, the slats 44 are simultaneously rotated to be in the open state. At this time, the front end 44B of the slat 44 is positioned on the right side of the rear end 44A, that is, on the outer side in the vehicle width direction.

  This modification can also exhibit the same effects as the basic embodiment. In particular, by opening the movable portion 22, as shown in FIG. 8B, the traveling wind W is introduced from the outside to the inside of the heat shield plate 21 and the hot air trapped inside the heat shield plate 21 is discharged. Thus, the exhaust purification device 1 can be actively cooled. Naturally, at this time, since the movable portion 22 opens also in the vicinity of the electric devices such as the injection valve 10 and the NOx sensor 7, the electric devices can be cooled to prevent damage due to thermal damage. The opening / closing control of the movable part 22 can also be performed in the same manner as in the basic embodiment.

  In this modification, as shown in FIG. 8C, the direction when the slat 44 is opened is reversed, and the front end 44B of the slat 44 is positioned on the left side of the rear end 44A, that is, on the inner side in the vehicle width direction. Good. In the example of FIG. 8B, hot air trapped inside the heat shield plate 21 is pushed out and discharged by the traveling wind W introduced from the outside to the inside. On the other hand, in the example of FIG. 8C, rather than introducing the traveling wind W, the heat shield H stays inside the heat shield 21 by using convection and wind from the fan F. 21 is discharged outside. Thus, the cooling of the exhaust emission control device 1 can be promoted only by discharging the hot air H.

(Second modification)
The second modification shown in FIGS. 9 and 10 is obtained by changing the first modification to a vertical opening type. That is, the entire heat shield plate 21 of the second modification is substantially a movable portion 22, and the movable portion 22 is formed by the louver 42. However, the louver 42 is changed as follows. 9 shows an open state of the movable portion 22, and FIG. 10 is a schematic rear view when FIG. 9 is viewed from the rear side except for the frame body 41. As shown in FIG.

  The louver 42 includes a plurality of blades 44 that open and close in a vertical opening manner by rotating around the horizontal axis 48. A lower end 44 </ b> C of the wing plate 44 is pivotally connected to the frame body 41 by a horizontal shaft 48. An operation part 45 is provided at the upper end 44D of the slat 44, and the operation part 45 of each slat 44 is connected by a connecting strip 46. As shown in FIG. 10, when the connecting strip 46 is pulled downward as indicated by an arrow, the slats 44 are simultaneously rotated to be in an open state. At this time, the upper end 44D of the slat 44 is positioned on the right side of the lower end 44C, that is, on the outer side in the vehicle width direction.

  This modification can also exhibit the same effects as described above. In particular, by opening the movable portion 22, as shown in FIG. 10, the hot air H trapped inside the heat shield plate 21 is raised using convection and the vehicle width using the wind from the fan F. It is possible to promote cooling of the exhaust emission control device 1 by discharging outward in the direction. Since the movable part 22 opens also in the vicinity of electrical devices such as the injection valve 10 and the NOx sensor 7, cooling of these electrical devices can be promoted to prevent damage due to thermal damage. The opening / closing control of the movable part 22 can also be performed in the same manner as in the basic embodiment.

  In this modification, the direction when the slat 44 is opened may be reversed, and the lower end 44C of the slat 44 may be positioned outside the upper end 44D in the vehicle width direction. Even in this case, the exhaust air purification device 1 can be cooled because the introduction of the traveling wind W and the discharge of the hot air H can be performed more actively than when the wing plate 44 is closed.

(Third Modification)
In the third modification shown in FIG. 11, a part of the heat shield plate 21 is a movable portion 22, and specifically, the door 24 of the basic embodiment (FIG. 5) is replaced with the vertical opening louver 42 of the second modification. Is. Since the details of the configuration and the operational effects are as described above, the description is omitted. Also according to this modification, the exhaust gas purification apparatus 1 can be efficiently cooled, and in particular, electric devices such as the injection valve 10 and the NOx sensor 7 can be efficiently cooled.

  In this modification, the direction when the slat 44 is opened may be reversed, and the opening / closing direction of the slat 44 may be changed to the lateral opening.

(Fourth modification)
Although not shown, the movable portion 22 may be formed by a combination of the door 24 and the louver 42. That is, the base of the movable portion 22 may be the door 24, and all or part of the door 24 may be the louver 42. As described above, the movable portion 22 includes at least one of the door 24 and the louver 42. For example, all or a part of the door 24 of the basic embodiment (FIG. 5) may be used as a vertically open or horizontally open louver 42.

  As mentioned above, although embodiment of this indication was described in detail, various embodiment of this indication can be considered variously.

  (1) For example, the heat shield structure of the present disclosure is applicable not only to the exhaust purification device 1 described above but also to a vehicle including a more general exhaust purification device in which a plurality of catalysts are simply arranged in series in the exhaust pipe. . In this case, it is possible to install the above-described heat shield plate in the vicinity of an arbitrary catalyst.

  (2) In the above-described embodiment, the exhaust purification device 1 and the heat shield plate 21 are arranged on the right side of the vehicle V. However, the installation positions are arbitrary, and may be arranged on the left side of the vehicle V, for example.

  (3) The number of doors 24 and louvers 42 is arbitrary, and at least one of doors 24 and louvers 42 may be provided on one heat shield plate 21.

  The configurations of the above-described embodiments and modifications can be combined partially or wholly unless there is a particular contradiction. The embodiment of the present disclosure is not limited to the above-described embodiment, and includes all modifications, applications, and equivalents included in the concept of the present disclosure defined by the claims. Therefore, the present disclosure should not be construed as being limited, and can be applied to any other technique belonging to the scope of the idea of the present disclosure.

DESCRIPTION OF SYMBOLS 1 Exhaust purification device 7 NOx sensor 10 Urea water injection valve 21 Heat shield plate 22 Movable part 24 Door 31 Actuator 42 Louver 100 Electronic control unit V Vehicle

Claims (4)

An exhaust purification device for purifying exhaust gas;
A heat shield plate that covers the exhaust purification device from the outside and has a movable part that can be opened and closed;
A heat insulation structure for a vehicle, comprising: The heat insulation structure for a vehicle according to claim 1, wherein an electric device is attached to the exhaust purification device, and the movable portion is disposed in the vicinity of the electric device. The heat insulation structure for a vehicle according to claim 1, wherein the movable portion includes at least one of a door and a louver. The vehicle blocking unit according to any one of claims 1 to 3, further comprising: an actuator that opens and closes the movable part; and a control unit configured to control the actuator according to a driving state of the vehicle. Thermal structure.

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