JP4826612B2 - Vehicle exhaust purification device arrangement structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a reducer from entering into a vehicle compartment even if a reducer tank breaks when the reducer tank is disposed on a vehicle, avoid harmful influence on steering stability of the vehicle, to suitably set position relation between a fuel tank and an exhaust pipe, and to inhibit harmful influence on vibration characteristics of a floor panel during vehicle travel. <P>SOLUTION: A vehicle comprising an exhaust-gas purification device 70 forming ammonia as reduction material for purifying components in exhaust gas by thermally decomposing urea water solution which is less toxic than ammonia and more fire-resistant than fuel, and purifying exhaust gas using the formed ammonia, is provided with a fuel tank 51, an urea tank 71 to accommodate urea water solution, and an exhaust system extending in a vehicle fore-and-aft direction and having an exhaust port 68 at a rear end, below a floor panel 2. The urea tank is disposed at a section behind the fuel tank and separated by a predetermined gap G in a vehicle lateral direction with respect to a silencer 66 of the exhaust system. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a structure for disposing an exhaust purification device for a vehicle that purifies exhaust gas from an internal combustion engine of the vehicle using a reducing substance.

When purifying nitrogen oxides (so-called NO _x ) contained in exhaust gas from an internal combustion engine (diesel engine, gasoline engine, etc.) of a vehicle such as an automobile, NO is provided in the middle of the engine exhaust pipe. Conventionally, it is common to make the _X- reduced catalyst pass through to be detoxified.

In recent years, it has been proposed to use ammonia as a reducing substance in order to increase the purification efficiency of the NO _X reduction catalyst. For example, when an aqueous urea solution is added into the exhaust pipe upstream of the reduction catalyst, the added aqueous urea solution is heated and decomposed by the exhaust of the engine to generate ammonia. This ammonia acts as a reducing substance, further promoting the detoxification of NO _x in the exhaust gas. That is, in this case, reducing substance for purifying NO _X components contained in engine exhaust (ammonia) is, and the flame retardancy of the reducing agent (urea solution) thermal degradation than the fuel at lower toxicity than the reducing substance The exhaust gas is purified by using the generated reducing substance.

  When such an exhaust purification system is employed, it is necessary to provide a tank (reducing agent tank) for storing a urea aqueous solution as a reducing agent and hold the reducing agent tank on the vehicle body. For example, Patent Document 1 proposes various arrangements (layouts) of such a reducing agent tank.

In the layout disclosed in Patent Document 1, a plurality of tanks are provided by using spaces such as the interior of the engine room and the side cowl, the lower side of the front seat in the vehicle interior, the bumper at the end of the vehicle, and the vehicle body frame. In addition, it is said that the capacity of the reducing agent tank can be increased and the replenishment frequency of the reducing agent can be kept low.
JP 2006-242092 A

  As is well known, ammonia is toxic and has a strong irritating odor, so even if the reducing agent tank breaks, the internal reducing agent (ammonia or aqueous urea solution) will leak and enter the passenger compartment. It must be surely prevented. Note that the temperature at which urea is easily decomposed to become ammonia (urea decomposition temperature) is generally about 150 ° C., but it is known that decomposed ammonia gas can be generated even at a temperature of about room temperature. Therefore, it is preferable to reliably prevent not only ammonia but also the urea aqueous solution from entering the passenger compartment.

  However, in most of the conventional layouts, the reducing agent tank is disposed above the vehicle body floor, and when the tank breaks, there is a possibility that the stored urea aqueous solution leaks and enters the vehicle interior. In particular, in the engine room, there are not a few devices and members whose surface temperature exceeds the urea decomposition temperature, so when a reducing agent tank is arranged in such an engine room, the leaked urea aqueous solution It has a strong tendency to be easily decomposed into ammonia, which has a more adverse effect.

  In addition, it is desirable that the reducing agent tank has a large capacity in order to keep the reducing agent replenishment frequency low, but when such a large capacity tank is mounted on a vehicle, in order to suppress an adverse effect on steering stability. For this reason, it is preferable to dispose it at the bottom of the vehicle body as much as possible.

  However, a fuel tank that stores fuel, an exhaust pipe that extends in the longitudinal direction of the vehicle and has an exhaust port at the rear end, and the like are usually provided at the lower part of the vehicle body (for example, below the floor panel). Since fuel for automobiles is more flammable than aqueous urea solution, fuel tanks require more consideration than reductant tanks when improving safety during vehicle collisions. In addition, the exhaust pipe becomes hot as it approaches the upstream side, so when laying out a tank of a reducing agent that decomposes by heat at a predetermined temperature or higher to generate toxic reducing substances, the positional relationship with the exhaust pipe is also important. You must consider it.

  In addition, as described above, it is desirable that the reducing agent tank has a large capacity in order to keep the reducing agent replenishment frequency low. However, when the large capacity tank is arranged at the lower part of the vehicle body (particularly below the floor panel). In some cases, there is a fear of increasing the vibration of the floor panel due to the vibration input while the vehicle is running.

  As described above, when determining the arrangement structure of the reducing agent tank on the vehicle body, in the unlikely event that the reducing agent tank is damaged, the reducing agent is prevented from entering the passenger compartment, the effect on the steering stability of the vehicle, It is required to consider comprehensively the safety of the fuel tank, the positional relationship with the exhaust pipe, and the influence on the vibration characteristics of the floor panel while the vehicle is running.

  This invention was made to solve these technical problems, and when the reducing agent tank is arranged in the vehicle, even if the reducing agent tank is temporarily damaged, the reducing agent can be prevented from entering the vehicle interior, Further, it is possible to avoid the adverse effect on the steering stability of the vehicle, furthermore, it is possible to suitably set the positional relationship between the fuel tank and the exhaust pipe, and further, it is possible to suppress the adverse effect on the vibration characteristics of the floor panel during vehicle travel, This is the basic purpose.

For this reason , the first invention of the present application generates a reducing substance for purifying components contained in exhaust gas by thermally decomposing a reducing agent that is less toxic than the reducing substance and flame-retardant than the fuel. In the vehicle equipped with the exhaust purification device that performs exhaust purification using the generated reducing substance, a fuel tank for storing the fuel, a reducing agent tank for storing the reducing agent, and a vehicle front and rear are provided below the floor panel. An exhaust pipe extending in the direction and having an exhaust port at the rear end is disposed, and the reducing agent tank is rearward of the fuel tank and separated from the exhaust pipe by a predetermined gap in the vehicle width direction. The reducing agent tank is arranged at the rear of the vehicle body, a silencer is provided in the exhaust pipe on the side of the reducing agent tank, and a clearance in the vehicle width direction between the reducing agent tank and the exhaust pipe Part bulges upward on the floor panel Is located immediately behind the tunnel portion extending in the vehicle longitudinal direction is formed such, that is obtained by it said.

Also, a second aspect of the present invention is a reducing substance for purifying components contained in the exhaust, the reducing agent of the flame-retardant than and fuel with a low toxicity generated by thermal decomposition than the reducing substance In the vehicle equipped with the exhaust purification device that performs exhaust purification using the generated reducing substance, a fuel tank for storing the fuel, a reducing agent tank for storing the reducing agent, and a vehicle front and rear are provided below the floor panel. An exhaust pipe extending in the direction and having an exhaust port at the rear end is disposed, and the reducing agent tank is rearward of the fuel tank and separated from the exhaust pipe by a predetermined gap in the vehicle width direction. The reducing agent tank is arranged at the rear of the vehicle body, a silencer is provided in the exhaust pipe on the side of the reducing agent tank, and a clearance in the vehicle width direction between the reducing agent tank and the exhaust pipe In front of the part, the reducing agent tank at the time of vehicle rear-end collision When said silencer is before moving, in which is characterized in that, the guide portion is provided having a shape which guides the direction away the vehicle width direction at least one relative to the other.

Further, a third aspect of the present invention is the second invention, the guide portion, and characterized by having a shape which rectifies traveling wind of the floor panel downward to pass through the gap portion It is a thing.

Furthermore, the fourth invention of the present application generates a reducing substance for purifying components contained in exhaust gas by thermally decomposing a reducing agent that is less toxic than the reducing substance and flame retardant than the fuel. In the vehicle equipped with the exhaust purification device that performs exhaust purification using the generated reducing substance, a fuel tank for storing the fuel, a reducing agent tank for storing the reducing agent, and a vehicle front and rear are provided below the floor panel. An exhaust pipe extending in the direction and having an exhaust port at the rear end is disposed, and the reducing agent tank is rearward of the fuel tank and separated from the exhaust pipe by a predetermined gap in the vehicle width direction. is disposed at the site, the lower surface of the floor panel supported by a pair of left and right rear side frames extending in the longitudinal direction of the vehicle body, and a rear end panel connected to the rear end portions of the left and right rear side frames, the Riyaendopane A structure that can suppress vibration of the floor panel is provided between a cross member that is positioned further forward and connects the left and right rear side frames, and the reducing agent tank includes at least one of the structure and the structure. It is characterized by being installed so as to straddle the lower side of one rear side frame.

Still further, according to a fifth aspect of the present invention, in the fourth aspect , the structure includes a vertical frame extending in a longitudinal direction of the vehicle body and a middle portion of the vertical frame in the longitudinal direction of the vehicle body toward the one rear side frame. It is characterized by comprising a lateral member extending in the direction.

Still further, according to a sixth aspect of the present invention, in the fourth aspect , the reducing agent tank is provided by a first band member disposed between the structure and the one rear side frame. It is characterized by being supported.

Still further, according to a seventh aspect of the present invention, in the sixth aspect , the structure includes a vertical frame extending in a longitudinal direction of the vehicle body and a middle portion of the vertical frame in the longitudinal direction of the vehicle body toward the one rear side frame. The first band member has a rear end fixed to a rear position of the one rear side frame, while a front end is fixed to the horizontal member of the structure. A second band member having front and rear ends fixed to a front part and a rear part of a vertical frame of the body is further provided, and the reducing agent tank is formed by the first band member and the second band member. It is characterized by being supported.

Still further, according to an eighth aspect of the present invention, in the fifth aspect, the horizontal member of the structure is formed in a substantially U-shaped longitudinal section, and the opening side thereof is joined to the lower surface of the floor panel. A closed cross-section portion is formed, and a gap is provided between the front end portion of the closed cross-section portion on the one rear side frame side and the rear side frame .

Still further, according to a ninth aspect of the present invention, in the fifth aspect , the cross member is disposed on an upper surface of the floor panel, and a front end portion of the vertical frame of the structure is coupled to the cross member. It is characterized by that.

Still further, according to a tenth aspect of the present invention, in the ninth aspect, the vertical frame is formed in a substantially U-shaped vertical cross section, and the opening side thereof is joined to the lower surface of the floor panel to thereby form a closed cross section. The closed cross section is configured such that the area of the peripheral shape of the vertical cross section gradually decreases at the front portion of the vertical frame.

Furthermore, an eleventh invention of the present application is characterized in that, in any one of the first to tenth inventions, the reducing agent is a urea compound.
Still further, in a twelfth aspect of the present invention based on any one of the first to eleventh aspects, the reducing agent tank has at least a substantially entire surface and a lower surface on the side facing the exhaust pipe covered with a cover body. It is characterized by that.
Still further, a thirteenth aspect of the present invention is characterized in that, in the twelfth aspect, the reducing agent tank and the cover body are supported via a support member that allows the vehicle body to swing. It is what.

According to the first aspect of the present gun, the reducing agent tank, because it is disposed below the floor panel, the vehicle interior is partitioned ensured by the floor panel, it is unlikely reducing agent tank corruption Even if the reducing agent in the tank leaks out, the leaking reducing agent is reliably prevented from entering the vehicle interior. In addition, by placing a reducing agent tank with volume and weight below the floor panel, the center of gravity of the vehicle body is lowered compared to the case where it is conventionally arranged in the engine room or side cowl or in the vehicle compartment. Furthermore, the center of gravity of the vehicle body can be brought closer to the center side in the front-rear direction than in the case where it is conventionally disposed in the bumper, which can contribute to the improvement of the steering stability of the vehicle.
In addition, by placing the reducing agent tank behind the fuel tank, the fuel tank that stores fuel that is more flammable than the aqueous urea solution is positioned closer to the center in the vehicle longitudinal direction than the reducing agent tank. It is possible to improve safety at the time of vehicle rear-end collision (collision from the rear). On the other hand, the reducing agent tank is disposed behind the fuel tank and at a position with a predetermined gap in the vehicle width direction with respect to the relatively downstream exhaust pipe that is relatively low in temperature. However, if the reducing agent in the tank leaks due to damage, the ambient temperature is not so high, so the leaking reducing agent is difficult to decompose by heating and generates toxic reducing substances. Can be suppressed.
Furthermore, the reducing agent tank is disposed at the rear part of the vehicle body, so that it is located at a part with a predetermined gap in the vehicle width direction with respect to the exhaust pipe on the downstream side at the rear part of the vehicle body, which is significantly cooler than the upstream side. Be placed. Moreover, since the exhaust pipe on the side of the reducing agent tank has a large surface area and a silencer that further lowers the exhaust temperature, even if the reducing agent tank breaks and the reducing agent leaks out and splashes into the silencer Since the surface temperature of the silencer is relatively low, the leaked reducing agent is difficult to thermally decompose, and generation of reducing substances can be more effectively suppressed.
In particular, since the gap in the vehicle width direction between the reducing agent tank and the exhaust pipe is positioned immediately after the tunnel portion formed so as to bulge upward on the floor panel and extending in the vehicle front-rear direction, By the underfloor running wind that blows through the tunnel portion, the exhaust pipe on the side of the reducing agent tank can be cooled more effectively, and the heat can be effectively shielded between the two.

According to a second aspect of the present gun, the reducing agent tank, because it is disposed below the floor panel, the vehicle interior is partitioned ensured by the floor panel, it is unlikely reducing agent tank corruption Even if the reducing agent in the tank leaks out, the leaking reducing agent is reliably prevented from entering the vehicle interior. In addition, by placing a reducing agent tank with volume and weight below the floor panel, the center of gravity of the vehicle body is lowered compared to the case where it is conventionally arranged in the engine room or side cowl or in the vehicle compartment. Furthermore, the center of gravity of the vehicle body can be brought closer to the center side in the front-rear direction than in the case where it is conventionally disposed in the bumper, which can contribute to the improvement of the steering stability of the vehicle.
In addition, by placing the reducing agent tank behind the fuel tank, the fuel tank that stores fuel that is more flammable than the aqueous urea solution is positioned closer to the center in the vehicle longitudinal direction than the reducing agent tank. It is possible to improve safety at the time of vehicle rear-end collision (collision from the rear). On the other hand, the reducing agent tank is disposed behind the fuel tank and at a position with a predetermined gap in the vehicle width direction with respect to the relatively downstream exhaust pipe that is relatively low in temperature. However, if the reducing agent in the tank leaks due to damage, the ambient temperature is not so high, so the leaking reducing agent is difficult to decompose by heating and generates toxic reducing substances. Can be suppressed.
Furthermore, the reducing agent tank is disposed at the rear part of the vehicle body, so that it is located at a part with a predetermined gap in the vehicle width direction with respect to the exhaust pipe on the downstream side at the rear part of the vehicle body, which is significantly cooler than the upstream side. Be placed. Moreover, since the exhaust pipe on the side of the reducing agent tank has a large surface area and a silencer that further lowers the exhaust temperature, even if the reducing agent tank breaks and the reducing agent leaks out and splashes into the silencer Since the surface temperature of the silencer is relatively low, the leaked reducing agent is difficult to thermally decompose, and generation of reducing substances can be more effectively suppressed.
In particular, when the reducing agent tank and the silencer move forward in the event of a rear-end collision, at least one of the reducing agent tank and the exhaust pipe is positioned in front of the gap in the vehicle width direction between the reducing agent tank and the exhaust pipe. Therefore, even if the reducing agent tank is damaged by the rear impact and the reducing agent leaks out, the leaked reducing agent will fall on the exhaust pipe. It can be effectively suppressed.

Also, according to the third aspect of the present invention, it can be basically same effect as the second aspect of the present invention. In particular, by using the guide portion, the traveling wind below the floor panel can be rectified so as to pass through a gap in the vehicle width direction between the reducing agent tank and the exhaust pipe, and the exhaust pipe on the side of the reducing agent tank. Can be cooled more effectively, and the heat can be shielded more effectively between the two.

According to a fourth aspect of the present gun, the reducing agent tank, because it is disposed below the floor panel, the vehicle interior is partitioned ensured by the floor panel, it is unlikely reducing agent tank corruption Even if the reducing agent in the tank leaks out, the leaking reducing agent is reliably prevented from entering the vehicle interior. In addition, by placing a reducing agent tank with volume and weight below the floor panel, the center of gravity of the vehicle body is lowered compared to the case where it is conventionally arranged in the engine room or side cowl or in the vehicle compartment. Furthermore, the center of gravity of the vehicle body can be brought closer to the center side in the front-rear direction than in the case where it is conventionally disposed in the bumper, which can contribute to the improvement of the steering stability of the vehicle.
In addition, by placing the reducing agent tank behind the fuel tank, the fuel tank that stores fuel that is more flammable than the aqueous urea solution is positioned closer to the center in the vehicle longitudinal direction than the reducing agent tank. It is possible to improve safety at the time of vehicle rear-end collision (collision from the rear). On the other hand, the reducing agent tank is disposed behind the fuel tank and at a position with a predetermined gap in the vehicle width direction with respect to the relatively downstream exhaust pipe that is relatively low in temperature. However, if the reducing agent in the tank leaks due to damage, the ambient temperature is not so high, so the leaking reducing agent is difficult to decompose by heating and generates toxic reducing substances. Can be suppressed.
In particular, since the reducing agent tank is installed so as to straddle the structure that can suppress the vibration of the floor panel and at least one of the rear side frames, it is sufficient to avoid interference with the rear side frame. A large tank capacity can be secured, and vibration of the floor panel can be suppressed.

Furthermore, according to the fifth invention of the present application, basically, the same operational effects as the fourth invention can be obtained. In particular, the structure is constituted by a vertical frame extending in the longitudinal direction of the vehicle body and a lateral member extending from a middle portion of the vertical frame in the longitudinal direction of the vehicle body toward the one rear side frame. The floor panel can be reinforced not only in the vehicle body longitudinal direction of the floor panel but also in the vehicle width direction, and the vibration of the floor panel can be more effectively suppressed.

Still further, according to the sixth invention of the present application, basically, the same operational effects as those of the fourth invention can be obtained. In particular, since the reducing agent tank is supported by a first band member that is disposed between the structure and the one rear side frame, for example, a vehicle collides from the rear (so-called Even when the rear side frame is deformed when receiving a rear impact, etc., the looseness of the first band member due to the deformation of the rear side frame is suppressed compared to the case where the front and rear of the band member are both fixed to the rear side frame. It is possible to effectively prevent the reducing agent tank from dropping off due to the deformation of the rear side frame.

Still further, according to the seventh invention of the present application, basically, the same operational effects as those of the sixth invention can be obtained. In particular, the structure is constituted by a vertical frame extending in the longitudinal direction of the vehicle body and a lateral member extending from a middle portion of the vertical frame in the longitudinal direction of the vehicle body toward the one rear side frame. The floor panel can be reinforced in both the vehicle body longitudinal direction and the vehicle width direction of the floor panel, and the vibration of the floor panel can be more effectively suppressed.
Further, specifically, the first band member has a rear end fixed to the rear position of one rear side frame and a front end fixed to the lateral member of the structure, for example, at the time of a rear collision. Even when the rear side frame is deformed in such a manner, loosening of the first band member due to the deformation of the rear side frame can be more effectively suppressed as compared to the case where the front and rear of the band member are both fixed to the rear side frame.
In addition, a second band member having front and rear ends fixed to the front and rear portions of the vertical frame of the structure is further provided, and the reducing agent tank is formed by the first band member and the second band member. Since it is supported, the reducing agent tank can be supported more stably.

Still further, according to the eighth invention of the present application, basically, the same operational effects as those of the fifth invention can be obtained. In particular, the transverse member of the structure is a vertical surface is formed substantially U-shape, but closed cross-section portion by which the open side is joined to the lower surface of the floor panel is formed, the of the closed-section portion Since a gap is provided between the front end of one rear side frame and the rear side frame (that is, the closed cross section of the lateral member and the rear side frame are not coupled), for example, at the time of a rear collision, etc. Even when the rear side frame is deformed, the deformation of the rear side frame is hardly transmitted to the lateral member. Accordingly, it is possible to effectively suppress the dropout of the reducing agent tank accompanying the deformation of the rear side frame.

Still further, according to the ninth invention of the present application, basically, the same operational effects as those of the fifth invention can be obtained. In particular, since the front end portion of the vertical frame of the structure is coupled to a cross member disposed on the upper surface of the floor panel, the vertical frame is coupled to the cross member at the front end portion in a rear collision. Using the part as a fulcrum, the rear end to which the collision load is input is easily deformed so as to be displaced obliquely downward, and the interference between the reducing agent tank located on the upper side of the vertical frame and the member located in front thereof is suppressed. can do.

Still further, according to the tenth aspect of the present invention, basically, the same operation and effect as the ninth aspect can be achieved. In particular, the longitudinal frame longitudinal section is formed substantially U-shape, its open side is configured the closed-section portion by being joined to a lower surface of the floor panel, the closed cross section, of the vertical frame before Since the area of the peripheral shape of the vertical cross section gradually decreases in the portion, the rear end of the vertical frame is oblique with the connecting portion with the cross member at the front end as a fulcrum. It becomes easier to be deformed so as to be displaced downward, and the interference between the reducing agent tank and the member located in front of it can be more effectively suppressed. Further, it is possible to secure a larger lower space in the front portion of the vertical frame and to easily avoid interference with members disposed below.

Still further, according to the eleventh invention of the present application, basically, the same operational effect as any one of the first to tenth inventions can be achieved. In particular, the reducing agent is a urea compound that has a relatively low toxicity and irritating odor and is liquid at room temperature, and is therefore relatively easy to handle. Even if the reducing agent tank breaks down and leaks from the tank, ammonia gas is hardly generated by thermal decomposition at room temperature, so that it does not have a significant adverse effect.
Still further, according to the twelfth aspect of the present invention, basically, the same operation and effect as any one of the first to eleventh aspects can be achieved. In particular, since the reducing agent tank is covered with a cover body at least approximately the entire surface facing the exhaust pipe and the lower surface, even if the reducing agent tank breaks and the reducing agent leaks out, The reducing agent leaked out is received by the cover body and hardly scattered in the exhaust pipe, and it is possible to prevent the reducing agent from scattering into the exhaust pipe and thermally decomposing to generate a reducing substance.
Still further, according to the thirteenth aspect of the present invention, basically the same function and effect as the twelfth aspect of the invention can be achieved. In particular, since the reducing agent tank and the cover body are supported via a support member that allows rocking with respect to the vehicle body, even if the supporting member breaks, the reducing agent tank falls together with the cover body. It is possible to prevent the reducing agent from splashing outside the cover body.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a bottom view showing a lower surface side of a vehicle body floor of an automobile equipped with an exhaust emission control device according to the present embodiment (a view seen from below), and FIG. 2 is a partially enlarged view showing a rear portion of the vehicle body in FIG. FIG. 3 is a bottom view, and FIG. 3 is a plan view showing the upper surface side of the vehicle body floor at the rear of the vehicle body. 4 is a cross-sectional view taken along line AA in FIG. 1, FIG. 5 is a partial cross-sectional view taken along line BB in FIG. 3, and FIG. 6 is a partial cross-sectional view taken along line CC in FIG. 7 and 7 are partial cross-sectional views along the line DD in FIG.

As can be clearly understood from FIG. 1, the vehicle according to the present embodiment includes a power transmission system from the engine unit 20 to a rear differential device 26 (so-called rear differential) on the lower side of the vehicle body floor panel 2, and the engine unit 20. And an engine exhaust system extending to the rear end of the vehicle body.
The power transmission system basically has the same configuration as that conventionally known, and the engine unit 20 integrally connects, for example, an internal combustion engine (engine), which is a diesel engine, and a transmission. The transmission output is transmitted to the rear differential device 26 via the propeller shaft 25, and the left and right wheel supports are respectively transmitted from the rear differential device 26 to the left and right drive shafts 27 (see FIG. 2). As a result, the left and right rear wheels 29 (see FIGS. 8A to 8C described later) are driven.

The floor panel 2 is formed with a floor member 3 having a closed cross section extending in the longitudinal direction of the vehicle body. These floor members 3 are formed on the left and right sides of the propeller shaft 25 and the engine exhaust system. And between these floor members 3, the tunnel part 4 which the shape bulged upwards by the front view extends in the vehicle body front-back direction is formed. The propeller shaft 25 and the engine exhaust system are passed through a space portion 4S (tunnel space) formed by the tunnel portion 4. The tunnel space 4S is extended to a position immediately after the rear differential device 26.
During traveling of the vehicle, components of the power transmission system such as the propeller shaft 25 and the rear differential device 26, and components of the engine exhaust system are generated by the underfloor traveling wind (see the broken line arrow Wd in FIG. 7) blowing through the tunnel space 4S Can be effectively cooled.

As shown in FIGS. 1 and 2, the vicinity of the left and right ends on the lower surface side of the floor panel 2 at the rear of the vehicle body 1 is supported by a pair of left and right rear side frames 6 (6L.6R) extending in the longitudinal direction of the vehicle body. The rear end portion of each rear side frame 6 is coupled to a rear end cross member 8 that extends in the vehicle width direction at the rear end of the vehicle body. The rear bumper 16 is attached to the rear end cross member 8 via a rear end panel 9 erected at the rear end of the vehicle body.
A center frame 7 extending in the longitudinal direction of the vehicle body substantially parallel to the rear side frame 6 is disposed at a position slightly deviated to either one (for example, to the left of the vehicle body) between the left and right rear side frames 6 (6L.6R). Has been. The rear end of the center frame 7 is also coupled to the rear bumper 16 via the rear end panel 9.

The middle portions in the front-rear direction of the left and right rear side frames 6 (6L.6R) are connected so as to be spanned by a cross member 11 (lower cross member) extending in the vehicle width direction. Further, an upper cross member 12 (see FIG. 3) extending in the vehicle width direction is disposed on the upper surface side of the floor panel 2 slightly behind the lower cross member 11. The front end of the center frame 7 is coupled to the upper cross member 12.
An intermediate cross member 13 extending in the vehicle width direction is disposed in front of the lower cross member 11 by a predetermined distance so as to span between the left and right rear side frames 6. A fuel tank 51 is disposed between the intermediate cross member 13 and the lower cross member 11.

The fuel tank 51 is made of, for example, a synthetic resin, and as shown in FIGS. 5 and 6, the lower surface thereof (preferably, the substantially lower half of the tank 51) is formed of, for example, an aluminum plate. 52 (insulator) and is suspended between the intermediate cross member 13 and the lower cross member 11 by a plurality of (for example, two on the left and right) support bands 53 stretched across the lower surface of the insulator 52. It is supported. The support band 53 is, for example, a known one made of metal and formed in a band shape. The support band 53 may be made of a resin having required mechanical characteristics.
An oil supply pipe 54 (see FIG. 2) for supplying fuel to the fuel tank 51 is led out from the rear part of the fuel tank 51 and is provided on the left side surface of the rear part of the vehicle body 1 and has an oil supply port 56 that opens to the outside of the vehicle compartment. 55 (see FIG. 3). The oil filler 55 is located in the vicinity of the rear opening 10 that opens the rear end of the passenger compartment to the outside of the passenger compartment (that is, connects the passenger compartment to the exterior of the passenger compartment). The rear opening 10 is covered with a rear gate 17 (see FIGS. 5 and 6) so as to be opened and closed.

A sub-frame 31 that supports the rear wheel suspension device 30 is disposed at a position corresponding to a middle portion of the rear side frame 6 in the front-rear direction. As can be seen from FIG. 2, the sub-frame 31 includes a pair of front and rear cross members (front cross member 32, rear cross member 33) extending in the vehicle width direction, and the front and rear cross members 32 extending in the front-rear direction of the vehicle body. , 33 and a pair of left and right side cross members 34, 35 that connect the vicinity of both left and right ends in the front-rear direction.
More preferably, a rear curved portion 33b is formed at the center of the rear cross member 33 in the vehicle width direction so as to be bent so that the center bulges rearward in plan view. The operation of the backward bending portion will be described later.

  Components such as a lower arm 41, various link members 42A to 42D, a spring 43, a dynamic damper 44 and the like constituting the rear wheel suspension device 30 are assembled to the subframe 31 to constitute a suspension assembly. It can be attached to the vehicle body 1 at a plurality of locations via elastic mount members.

Next, the engine exhaust system will be described.
As shown in FIG. 1, the engine exhaust system extends in the longitudinal direction of the vehicle body substantially along the propeller shaft 25 of the power transmission system. Basically, the exhaust purification system uses an aqueous urea solution as a reducing agent. The first exhaust pipe 61, the upstream catalyst unit 62, the second exhaust pipe 63, the downstream catalyst unit 64, the first exhaust pipe 61, and the downstream catalyst unit 64 are arranged in order from the engine exhaust port to the downstream side. 3 exhaust pipe 65, silencer 66, and fourth exhaust pipe 67 are provided.

  The upstream end of the first exhaust pipe 61 communicates with the exhaust port of the engine, and the downstream end is connected to the upstream catalyst unit 62. The second exhaust pipe 63 is located between the upstream side catalyst unit 62 and the downstream side catalyst unit 64, and a urea aqueous solution as a reducing agent is injected into the second exhaust pipe 63, as will be described later. The third exhaust pipe 65 has an upstream end communicating with the downstream catalyst unit 64 and a downstream end connected to the silencer 66. The fourth exhaust pipe 67 has an upstream end communicating with the silencer 66, and a downstream end formed with an exhaust port 68. Since the silencer 66 has a very large surface area, the temperature of the exhaust gas is greatly reduced at this portion. Note that at least a part of the fourth exhaust pipe 67 and the first exhaust pipe 61 may be formed of a flexible tube that can be bent.

  The upstream side catalyst unit 62 is the same as a conventionally known one, and includes an oxidation catalyst and an exhaust particulate collector (so-called DPF), and hydrocarbons (HC) in exhaust gas and Carbon monoxide (CO) is oxidized, and particulate matter (so-called PM) in the exhaust gas is collected by passing through a DPF provided with a porous filter to purify the exhaust gas.

The exhaust gas purification device 70 incorporated in the exhaust system on the downstream side of the upstream catalyst unit 62 purifies nitrogen oxide (NO _x ) in the exhaust gas by a so-called SCR method. The downstream catalyst unit 64 itself is the same as a conventionally known one, and incorporates an upstream catalyst and a downstream catalyst. Upstream catalyst, the NO _X in the exhaust gas as to purify by reducing substance and catalytic reaction of ammonia, the so-called selective catalytic reduction catalyst. On the other hand, the downstream catalyst is a surplus reducing agent oxidation catalyst for decomposing surplus ammonia and preventing so-called ammonia slip (a phenomenon in which ammonia is released to the atmosphere).

In the exhaust purification device 70 according to the present embodiment, when ammonia is used as a reducing substance in order to increase the purification efficiency of the NO _X reduction catalyst, the second exhaust pipe 63 located upstream of the upstream catalyst of the downstream catalyst unit 64 is used. An aqueous urea solution is added as a reducing agent.
For this reason, the urea pipe 72 is led from the reducing agent tank 71 (urea tank) held below the floor panel 2, and its terminal is connected to the branch pipe 63 b of the second exhaust pipe 63. The connection terminal of the urea pipe 63 is more preferably connected to an injection nozzle (not shown) provided in the branch pipe 63b. Although not specifically shown, a pump is built in the urea tank 71, and an aqueous urea solution is fed through the urea pipe 72 by the discharge action of the pump, and is downstream in the second exhaust pipe 63. The part is injected and supplied.

Thus, the urea aqueous solution added upstream of the downstream side catalyst unit 64 is heated and decomposed by the exhaust of the engine to generate ammonia. This ammonia acts as a reducing substance, further promoting the detoxification of NO _x in the exhaust gas.
The aqueous urea solution has relatively low toxicity and irritating odor compared to ammonia, and is relatively easy to handle because it is liquid at room temperature. That is, in this case, reducing substance for purifying NO _X components contained in engine exhaust (ammonia) is, and the flame retardancy of the reducing agent (urea solution) thermal degradation than the fuel at lower toxicity than the reducing substance The exhaust gas is purified by using the generated reducing substance.

In this case, even if the reducing agent tank (urea tank 71) is damaged and leaks from the tank, ammonia gas is hardly generated by thermal decomposition at room temperature, so that it does not have a great adverse effect.
The exhaust gas purification device 70 according to the present embodiment is configured by the urea supply system including the urea tank 71 and the urea pipe 72, the second exhaust pipe 63 to which the urea aqueous solution is supplied, and the downstream side catalyst unit 64. Yes.

In the present embodiment, when the urea tank 71 is laid out, the urea tank 71 is disposed below the floor panel 2 as described above, and is located behind the fuel tank 51 and with respect to the exhaust system. It arrange | positions in the location which separated the predetermined gap G in the vehicle width direction.
That is, the urea tank 71 is separated from the silencer 66 of the exhaust system and a predetermined gap G in the vehicle width direction between the subframe 31 of the suspension assembly at the rear of the vehicle body and the rear end cross member 8 below the floor panel 2. Has been placed. Accordingly, the fuel tank 51 is located far behind the fuel tank 51 disposed between the intermediate cross member 13 and the lower cross member 11.

  Thus, by arranging the urea tank 71 below the floor panel 2, the urea tank 71 is surely partitioned from the passenger compartment by the floor panel 2, and the urea tank 71 is damaged by any chance. Even if the urea aqueous solution in 71 leaks out, this leaked urea aqueous solution is reliably prevented from entering the vehicle compartment. Further, by arranging the urea tank 71 having a volume and weight below the floor panel 2, the center of gravity of the vehicle body can be increased as compared with the case where the urea tank 71 is conventionally arranged in the engine room or the side cowl or in the vehicle interior. In addition, the center of gravity of the vehicle body can be brought closer to the center side in the front-rear direction compared to the case where it is conventionally disposed in the bumper, which contributes to the improvement of the steering stability of the vehicle. it can.

  Further, since the urea tank 71 is disposed behind the fuel tank 51, the fuel tank 51 storing fuel that is more flammable than the urea aqueous solution is positioned on the center side in the vehicle longitudinal direction as compared with the urea tank 71. Therefore, the safety at the time of rearward collision of the vehicle (collision from the rear) can be further enhanced. On the other hand, the urea tank 71 is separated from the fuel tank 51 by a predetermined gap G in the vehicle width direction behind the relatively downstream exhaust system (specifically, the silencer 66) that is relatively low in temperature. Therefore, even if the urea tank 71 is damaged and the urea aqueous solution in the tank 71 leaks out, the ambient temperature is not so high, so the leaked urea aqueous solution is difficult to be thermally decomposed. It is possible to suppress the generation of ammonia having a slight toxicity and an irritating odor.

  In particular, the urea tank 71 is disposed at the rear portion of the vehicle body 1 so as to be disposed at a predetermined gap G in the vehicle width direction with respect to the exhaust system on the downstream side, which is significantly cooler than the upstream side. can do. In addition, since the silencer 66 having a large surface area and further lowering the exhaust temperature is located in the exhaust system on the side of the urea tank 71, the urea tank 71 should be damaged and the urea aqueous solution in the tank 71 leaks out and the silencer Even if scattered to 66, since the surface temperature of the silencer 66 is relatively low, the urea aqueous solution is not easily thermally decomposed, and generation of ammonia can be more effectively suppressed.

Next, a specific arrangement structure of the urea tank 71 will be described.
The urea tank 71 is made of, for example, synthetic resin, and at least substantially the entire right side and the lower surface facing the exhaust system (in this case, the silencer 66) are covered with a cover body 73 (insulator). As shown in FIGS. 4 to 6, the cover body 73 is preferably formed in a so-called “tub” shape that is recessed downward, for example, using an aluminum plate material. Most of the side surfaces are covered with the cover body 73.
Therefore, even if the urea tank 71 is damaged and the urea aqueous solution in the tank 71 leaks, it is prevented that the leaked urea aqueous solution is directly scattered in the exhaust system. Generation of ammonia is suppressed.

  The urea tank 71 is connected between the sub-frame 31 of the suspension assembly and the rear end cross member 8 by a plurality of (for example, two left and right) support bands 74 (74L, 74R) stretched across the lower surface of the urea tank 71. Suspended and supported. In FIG. 2, the urea tank 71 is shown with the cover body 73 removed in order to clearly show the support structure of the urea tank 71 by the support band 74.

More specifically, as can be seen from FIGS. 1, 2 and 6, the portion near the right end of the urea tank 71 is located below the center frame 7, and preferably has an elastic cushioning material 75 (see FIG. 6). ) To contact the lower surface of the center frame 7. The front and rear ends of the right support band 74R are fixed to the lower surface of the center frame 7 using screw members 76.
On the other hand, as can be seen from FIG. 1, FIG. 2, FIG. 4 and FIG. 5, the portion near the left end of the urea tank 71 is located below the left side side frame 6L, and has an elastic cushion material (not shown). In contact with the lower surface of the rear side frame 6L. Further, the center front end portion of the urea tank 71 is positioned below the lateral member 14 extending from the middle portion of the center frame 7 toward the rear side frame 6L. The rear end of the left support band 74L is fixed to the lower surface of the rear side frame 6L, and the front end is fixed to the lower surface of the horizontal member 14 using a screw member 77 (see FIG. 5).

  As shown in FIG. 3, this arrangement position of the urea tank 71 corresponds to the left side of the rear part of the passenger compartment, and the inlet 81 for replenishing the urea tank 71 with the aqueous urea solution is provided on the side of the tire pan 5. In the vicinity of the rear left corner of the passenger compartment.

  If the right support band 74R is described as an example between the support band 74 (74L, 74R) and the lower surface of the urea tank 71, more preferably, a band cover 78 is interposed as shown in FIG. The cover body 73 has a plurality of mounting portions 73m that bulge upward, and uses bolts 79b and nuts 79n with the support band 74 and the band cover 78 sandwiched between the two 74, 78. It is fixed. Then, the support band 74 is stretched over the lower surface of the urea tank 71, so that the entire lower surface of the urea tank 71 and most of the side surfaces are covered with the cover body 73. In a region other than the attachment portion 73m, a space portion 80 is formed between the cover body 73 and the surface of the urea tank 71, and is shielded by being covered with the cover body 73 by the air layer of the space portion 80. Heat effect is enhanced. The support band 74 and the band cover 78 are known ones made of, for example, metal and formed in a band shape, like the support band 53 of the fuel tank 51. The support band 74 and the band cover 78 may be made of resin having required mechanical characteristics.

  The support band 74 (74L, 74R) is configured such that cushion materials 75, 75 interposed between the urea tank 71 and the vehicle body (center frame 7 in the example of FIG. 6) cause the urea tank 71 to swing and vibrate. In order to absorb the minute strokes to be absorbed by minute expansion and contraction and elastic deformation, vibrations are slightly expanded and contracted. Therefore, vibrations are generated on the vehicle body (especially on the floor panel 2 and its lower components) while the vehicle is running. In response to this, the urea tank 71 and the cover body 73 swing slightly in the expansion / contraction range of the support band 74. That is, in addition to this, the urea tank 71 is supported by the cover body 73 via a support member (support band 74) that allows the vehicle body 1 to swing.

Thereby, the vibration generated below the floor panel 2 due to the traveling of the vehicle or the like is effectively suppressed from being transmitted from the urea tank 71 to the passenger compartment.
In particular, since the urea tank 71 and the cover body 73 are both supported via the support band 74 that allows the vehicle body 1 to swing, even if the support band 74 breaks, the urea tank 71 falls together with the cover body 73, and the urea aqueous solution is prevented from scattering to the outside of the cover body 73.

  As described above, the urea tank 71 is disposed between the silencer 66 and the silencer 66 with a predetermined gap G in the vehicle width direction (see FIG. 1). It is located immediately after the part 4. As described above, the tunnel portion 4 is formed so as to bulge upward in a front view and extends in the front-rear direction of the vehicle body. The propeller shaft 25 and the engine exhaust system are passed through the tunnel space 4S. The space 4S extends to a position just behind the rear differential device 26. That is, the gap G between the urea tank 71 and the silencer 66 is located immediately behind the rear differential device 26.

  By adopting such a layout, the exhaust system on the side of the urea tank 71 (in this case, the silencer 66) is more effectively caused by the underfloor traveling wind Wd (see FIG. 7) that blows through the tunnel portion 4S during traveling of the vehicle. Cooling can be performed, and heat can be effectively shielded between the urea tank 71 and the silencer 66.

Further, immediately before the gap G in the vehicle width direction between the urea tank 71 and the silencer 66 and immediately after the rear differential device 26, the urea tank 71 at the time of a rear collision (collision from the rear). A guide member 91 for improving safety is provided (see FIGS. 2 and 7).
The guide member 91 is configured using, for example, a case body of a dynamic damper 44 attached to the sub-frame 31 of the suspension assembly, and forms a taper that expands toward the front in plan view. And a flat plate-like rear end piece 91b extending backward from the base point of the inclined surface portion 91a by a predetermined length.

By providing such a guide member 91 immediately before the gap G in the vehicle width direction between the urea tank 71 and the silencer 66, when the urea tank 71 and the silencer 66 move forward during a vehicle rear-end collision. At least one of the guide members 91 is guided in a direction away from the other in the vehicle width direction by the left and right slope portions 91a.
Therefore, even if the urea tank 71 is damaged due to the rear impact and the urea aqueous solution in the tank 71 leaks, the leaked urea aqueous solution is effectively suppressed from falling on the silencer 66.

  The guide member 91 expands as it goes forward (that is, it becomes tapered as it goes backward), and right and left slope portions 91a, and a predetermined rearward from the base point of these slope portions 91a. When the traveling wind Wd flows below the floor panel 2 (particularly in the tunnel space 4S), the traveling wind Wd is used as a urea tank. Rectification can be performed so as to pass through the gap G in the vehicle width direction between 71 and the silencer 66. Thereby, the silencer 66 on the side of the urea tank 71 can be cooled more effectively, and the space between the both 71 and 66 can be shielded more effectively.

Note that, by using the shape of the sub-frame 31 of the suspension assembly, an action similar to the action at the time of the rear impact of the guide member 91 can be performed.
8A, 8B, and 8C are a series of explanatory views for explaining the crushing mode control of the urea tank 71 using the shape of the subframe 31, and FIG. 8A is a diagram illustrating urea in a normal state. FIG. 8B is a bottom view showing the crushing mode of the urea tank 71 at the time of a large collision, and FIG. 8C is a bottom view showing the crushing mode of the urea tank 71 at the time of a light collision. is there.

  As described above, the rear cross member 33 of the sub-frame 31 of the suspension assembly has a rear curved portion curved in the center in the vehicle width direction so that the center in the vehicle width direction bulges rearward in plan view. 33b is formed. The planar shape of the rear curved portion 33b is similar to the “taper expanding toward the front” in the guide member 91.

In the case of a light collision (collision load F2) in which the urea tank 71 does not exert a large load on the rear cross member 33 of the sub-frame 31, as shown in FIG. 8C, the urea tank 71 and the silencer 66 Only moves forward, and the urea tank 71 is hardly damaged.
On the other hand, when the urea tank 71 applies a large load to the rear cross member 33 during a large collision (collision load F1), as shown in FIG. However, in this case, the front side of the center portion of the rear cross member 33 in the vehicle width direction is in contact with the rear end portion of the rear differential device 26, and the left and right ends of the rear cross member 33 are moved forward. Since the cross member 33 is bent, at least one of the urea tank 71 and the silencer 66 moving forward is guided in a direction away from the other in the vehicle width direction. Accordingly, it is possible to achieve the same effect as when the guide member 91 is provided immediately before the gap G in the vehicle width direction between the urea tank 71 and the silencer 66.

Next, the positional relationship between the inlet 81 for supplying the urea aqueous solution to the urea tank 71 and the fuel filler port 56 of the fuel tank 51 will be described.
As shown in FIG. 3, the fueling portion 55 having the fueling port 56 of the fuel tank 51 is provided on the left side surface of the rear portion of the vehicle body 1 as described above, and the fueling portion 55 opens and closes the fueling port 56. And a cap 57 that is located in the vicinity of the rear opening 10 that communicates the interior of the vehicle with the outside of the vehicle at the rear end of the vehicle.

  On the other hand, the urea tank 71 is suspended and supported below the floor panel 2 between the suspension assembly subframe 31 and the rear end cross member 8 at a position corresponding to the left side of the rear portion of the passenger compartment. The inlet 81 for replenishing the urea tank 71 with the aqueous urea solution is disposed in the vicinity of the rear left corner of the passenger compartment on the side of the tire pan 5 of the floor panel 2.

  Thus, in this embodiment, although the urea tank 71 is disposed outside the vehicle compartment (below the floor panel 2), the inlet 81 of the urea tank 71 is provided in the vehicle interior. Therefore, even if the urea tank 71 is damaged and the urea aqueous solution in the tank 71 leaks out, the leaked urea aqueous solution can be reliably prevented from entering the vehicle interior, and the fuel that opens outside the vehicle compartment can be prevented. It is prevented from being confused with the oil supply port 56 of the tank 51 and the injection port (not shown) of a washer tank that normally opens in the engine room. As a result, it is possible to reliably prevent erroneous injection of fuel or washer fluid into the urea tank 71 or vice versa.

  4 and 5, the inlet 81 of the urea tank 71 is disposed at a position facing the urea tank 71 on the vehicle interior wall (floor panel 2) in the vehicle exterior / external direction. . Thereby, the injection port 81 can be provided in the vicinity of the urea tank 71, and the injection path from the injection port 81 to the urea tank 71 is further shortened and simplified.

  The injection port 81 includes a floor-side opening 85 and a tank-side opening 83 that is separated from the floor-side opening 85. The tank side opening 83 is formed at the upper end of an injection cylinder 82 made of, for example, synthetic resin and protrudes from the upper surface of the urea tank 71, and is provided with a cap 84 (tank side cap) for opening and closing the same. The floor-side opening 85 is formed by a hole provided in the floor panel 2, and the floor-side opening 85 is also provided with a cap 86 (floor-side cap) that opens and closes the floor-side opening 85. The floor-side cap 86 is attached so as to be removable and cover the hole (the floor-side opening 85) of the floor panel 2 using a plurality of screw members 89 (see FIG. 3). In the assembled state of the urea tank 71 to the vehicle body 1, the upper surface of the tank side cap 84 is separated from the lower surface of the floor side cap 86 by a predetermined distance or more.

As described above, since the tank-side opening 83 includes the cap 84, even if a relative movement occurs between the urea tank 71 and the vehicle body 1 in the event of a vehicle collision, the tank-side opening 83 has the cap 84. The urea aqueous solution can be prevented from leaking out from the inlet 81.
Furthermore, by providing the cap 86 in the floor side opening 85, it is possible to more reliably prevent the urea aqueous solution from leaking out from the inlet 81 and entering the vehicle interior. Further, it is possible to prevent outside air and muddy water from entering the vehicle compartment from below the floor panel 2.

  As described above, the urea tank 71 is supported via the support member (support band 74) that allows the vehicle body 1 to swing, and vibration generated below the floor panel 2 due to traveling of the vehicle or the like. The urea tank 71 is effectively suppressed from being transmitted to the passenger compartment, but the inlet 81 of the urea tank 71 is composed of a floor-side opening 85 and a tank-side opening 83 that are spaced apart from each other. Between the two 85 and 83 (more specifically, between the upper surface of the tank-side cap 84 and the lower surface of the floor-side cap 86), a gap K of a predetermined distance or more is provided. Therefore, even if the urea tank 71 swings with respect to the vehicle body 1 (with respect to the floor panel 2) while the vehicle is running, the upper surface of the tank side cap 83 and the lower surface of the floor side cap 86 do not interfere with each other. It is possible to follow the swinging motion of the urea tank 71 without any trouble.

  The space 87 between the floor side opening 85 and the tank side opening 83 is covered with a flexible covering cover 88 made of, for example, rubber, cloth or soft resin. The lower end portion of the covering cover 88 is attached to the outer peripheral portion of the injection cylinder 82 on the tank 71 side, and the upper end portion is attached in the vicinity of the peripheral edge of the floor side opening 85. The covering cover 88 is configured to be more fragile (that is, easily damaged) than a member (floor panel 2) that forms the floor-side opening 85 and a member (injection cylinder 82) that forms the tank-side opening 83. .

  As described above, the space 87 between the floor side opening 85 and the tank side opening 83 is covered with the covering cover 88, so that outside air and muddy water enter the vehicle interior via the floor side opening 85. It can be prevented more reliably. In this case, the covering cover 88 can absorb a minute swinging operation of the urea tank 71 with respect to the vehicle body 1 within the range of flexibility. In addition, since the covering cover 88 is configured to be more fragile than the members 2 and 82 that form the openings 85 and 83, respectively, the urea tank 71 with respect to the vehicle body 1 exceeds the range that can be absorbed by the flexibility of the covering cover 88. When the swinging operation occurs, it is possible to avoid an excessive force from acting on the members 2 and 82 that form the openings 85 and 83, respectively, by damaging the covering cover 88 first.

  As described above, the fuel filler port 56 of the fuel tank 51 is provided on the left side surface of the rear portion of the vehicle body 1, and in the vicinity of the rear opening 10 that connects the interior of the vehicle to the outside of the vehicle compartment at the rear end of the vehicle compartment (therefore, the rear gate 17. In the vicinity). On the other hand, the inlet 81 in the urea tank 71 is disposed in the vicinity of the rear left corner of the vehicle compartment on the side of the tire pan 5 and is also positioned in the vicinity of the rear gate 17. That is, both the inlet 81 of the urea tank 71 and the fuel filler 56 of the fuel tank 51 are disposed on the left side portion of the rear part of the vehicle body.

  As described above, the inlet 81 of the urea tank 71 and the fuel filler 56 of the fuel tank 51 are arranged close to each other near the same opening / closing body (rear gate 17). There is no need to change the stop position with respect to the supply facility. That is, for example, when the inlet 81 of the urea tank 71 and the fuel filler 56 of the fuel tank 51 are provided separately on the left side and the right side of the vehicle, or even on the same side, they are greatly separated in the front-rear direction. There is no need to change the stop position of the vehicle according to the replenishment target as in the case where the vehicle is replenished. Moreover, there is no need to worry about the occurrence of misinjection due to a wrong stop position. In this case, the stop position may be selected so that the left side portion of the rear portion of the vehicle body 1 faces the urea aqueous solution or fuel supply facility.

  By the way, it is desirable that the urea tank 71 has a large capacity in order to keep the frequency of urea replenishment low, but when the large capacity tank 71 is arranged at the lower part of the vehicle body (particularly below the floor panel 2). There is a fear of increasing the vibration of the floor panel 2 due to the vibration input during traveling of the vehicle. Therefore, when the urea tank 71 is disposed below the floor panel 2, it is required to consider so as to suppress an adverse effect on the vibration characteristics of the floor panel 2 while the vehicle is traveling.

  In the following, an embodiment (hereinafter referred to as “second embodiment”) for showing the arrangement structure of the urea tank below the floor panel in more detail will be described. In the following description, the same configuration as in the above-described embodiment described below with reference to FIGS. 1 to 8 (hereinafter referred to as the “first embodiment”) has the same function. Are denoted by the same reference numerals, and further description thereof is omitted.

  FIG. 9 is a partially enlarged bottom view showing the rear part of the vehicle body on the lower surface side of the vehicle body floor of an automobile equipped with the exhaust gas purification apparatus according to the second embodiment, and FIG. 10 shows the propeller shaft and the rear differential device from FIG. FIG. 11 is a partially enlarged bottom view of the rear part of the vehicle body floor in which the power transmission system including the rear wheel suspension system including the drive shaft and the rear wheel suspension device is deleted, and FIG. 11 further deletes the fuel pipe and the urea tank from FIG. FIG. 12 is a left side view of FIG. 10, FIG. 13 is a partial sectional view taken along line EE in FIG. 10, and FIG. It is explanatory drawing which added and showed a part of rear-wheel suspension apparatus to the partial cross section along.

  The difference between the first embodiment and the second embodiment is that the silencers 66 and 96 provided in the exhaust system are basically large in the first embodiment (silencer 66). In contrast, the second embodiment (silencer 96) is only reduced in size. The arrangement structure of the urea tank 71 below the floor panel 1 is substantially the same in both embodiments, but the second embodiment explains the arrangement structure of the urea tank 71 in more detail. It is.

  As shown in FIGS. 9 to 11, in the automobile according to the present embodiment, the left and right rear side frames on the lower surface of the floor panel 2 supported by a pair of left and right rear side frames 6 (6L, 6R) extending in the longitudinal direction of the vehicle body. A rear end panel 9 is connected to the rear ends of 6L and 6R, and a cross member 12 (upper cross member) is connected so as to span the left and right rear side frames 6L and 6R in front of the rear end panel 9 by a predetermined distance. Is arranged. The upper cross member 12 is disposed on the upper surface side of the floor panel 2 as can be seen from FIGS. 13 and 14. Further, slightly lower than the upper cross member 12, the lower cross member 11 disposed in parallel with the upper cross member 12 is positioned on the lower surface side of the floor panel 2.

  As can be seen from FIGS. 10 and 11, between the rear end panel 9 and the upper cross member 12, one of the structures that can suppress the vibration of the floor panel 2 (on the left side in the present embodiment). A tank support structure 15 that supports the urea tank 71 together with the rear side frame 6L is disposed. The tank support structure 15 includes a center frame 7 as a vertical frame extending in the longitudinal direction of the vehicle body between the left and right rear side frames 6L and 6R substantially parallel to these frames, and a middle portion of the center frame 7 in the longitudinal direction of the vehicle body. It is composed of one lateral member 14 extending toward the rear side frame 6L (on the left in the present embodiment). The horizontal member 14 and the center frame 7 may be manufactured integrally, or separate members may be joined and integrated.

  The center frame 7 has a front end joined to an upper cross member 12 and a rear end joined to a rear end panel 9. As shown in FIG. 4, the center frame 7 has a substantially U-shaped longitudinal section, and its opening side is joined to the lower surface of the floor panel 2 via a flange portion to form a closed section. Yes. Further, as shown in FIG. 13, the horizontal member 14 also has a substantially U-shaped vertical cross section, and its open side is joined to the lower surface of the floor panel 2 via a flange portion to form a closed cross section. Yes.

  By arranging the tank support structure 15 composed of the center frame 7 and the lateral member 14 to be joined to the lower surface side of the floor panel 2, both the vehicle body longitudinal direction and the vehicle width direction of the floor panel 2 are arranged. The floor panel 2 can be reinforced and vibration of the floor panel 2 can be more effectively suppressed.

  The urea tank 71 is installed so as to straddle the tank support structure 15 capable of suppressing the vibration of the floor panel 2 and the left rear side frame 6L. Therefore, sufficient tank capacity can be ensured while avoiding interference with the rear side frame 6L, and vibration of the floor panel 2 can be suppressed.

  A left band member 74L (first support band) for hanging and supporting the left side portion of the urea tank 71 between the tank support structure 15 and the left rear side frame 6L so as to span between the two. ) Is stretched. The mounting structure of the first support band 74L will be described more specifically. The rear end of the first support band 74L is fastened and fixed to the rear position of the left rear side frame 6L, while the front end is the tank support structure 15. The horizontal member 14 is fastened and fixed.

  In this manner, the urea tank 71 is supported by the first support band 74L that is stretched between the tank support structure 15 (the lateral member 14 thereof) and the left rear side frame 6L (the rear position). Thus, for example, when a vehicle receives a collision from behind (so-called rear collision) and a collision load is input from the rear to the rear side frame 6L coupled to the rear end of the bumper beam 16B, the rear side frame Even when the 6L is deformed, the first support band 74L is prevented from loosening due to the deformation of the rear side frame 6L and the deformation of the rear side frame 6L is suppressed as compared with the case where both the front and back of the support band 74L are fixed to the rear side frame 6L. It is possible to effectively prevent the urea tank 71 from dropping off.

  Further, a right side band member 74R (second support band) for hanging and supporting the right side portion of the urea tank 71 is stretched on the center frame 7 of the tank support structure 15. The mounting structure of the second support band 74R will be described in more detail. The front end of the second support band 74R is fastened and fixed at the front position of the center frame 7, while the front end is also at the rear position of the center frame 7. Fastened and fixed.

The urea tank 71 has a left side portion supported by the first support band 74L and a right side portion supported by the second support band 74R.
Thus, the urea tank 71 can be supported more stably by supporting the urea tank 71 with the first support band 74L and the second support band 74R.
The elastic characteristics of the first support band 74L and the second support band 74R, the structure for fastening and fixing both ends, the structure for supporting the urea tank 71 on the vehicle body side using the support bands 74L and 74R, and the like are described above. This is the same as in the first embodiment.

  As described above, the horizontal member 14 of the tank support structure 15 is joined to the lower surface of the floor panel 2 and has a closed cross-sectional structure, and between this closed cross-sectional portion and the left rear side frame 6L. Is provided with a predetermined gap. In other words, the closed cross section of the lateral member 14 and the left rear side frame 6L are not coupled. Therefore, for example, even when the rear side frame 6L is deformed at the time of a rear collision or the like, the deformation of the rear side frame 6L is difficult to be transmitted to the lateral member 14, and the urea tank 71 is effectively removed due to the deformation of the rear side frame 6L. It is comprised so that it can suppress.

  The closed cross-section portion of the lateral member 14 is a portion having high strength and rigidity and high load transmission capability. However, the strength and rigidity of, for example, a simple flat plate is low on the tip side of the closed cross-section portion, and the load transmission capability is low. A low edge portion may be provided, and at the time of assembling the vehicle body, the edge portion may be coupled to the left rear side frame 6L and used for temporary assembly or the like. Since such an edge portion has low strength and rigidity, when a large load is applied such that the rear side frame 6L is deformed at the time of a rear collision, the connection with the rear side frame 6L is easily released, and the rear side frame 6L Is prevented from being transmitted to the lateral member 14.

  12, the left and right rear side frames 6L and 6R have the longitudinal center line Ma of the frame rear portion 6a positioned behind the portion coupled to the lower cross member 11 at the lower cross member 11. It is located above the longitudinal center line Mb of the frame front part 6b located in front of the joined part by a predetermined amount.

  By configuring the rear side frames 6L and 6R in this way, when a collision load is input from the rear ends of the rear side frames 6L and 6R at the time of rearward collision of the vehicle, the connecting portion with the lower cross member 11 is used as a fulcrum. The rear end to which the collision load is input can be deformed so as to be displaced obliquely downward, effectively absorbing the collision energy, and suppressing the forward movement of the urea tank 71 and the fuel tank 51 as much as possible, Interference between the tanks 71 and 51 and a member located in front of the tanks 71 and 51 can be suppressed as much as possible.

  As described above, the front end portion of the center frame 7 of the tank support structure 15 is not the lower cross member 11 disposed on the lower surface of the floor panel 2 but the upper cross member 12 disposed on the upper surface of the floor panel 2. Is bound to. Therefore, at the time of rearward collision of the vehicle, the center frame 7 does not stretch in the front-rear direction as in the case of being coupled to the lower cross member 11, and the collision is performed with the coupling portion with the upper cross member 12 at the front end as a fulcrum. The rear end portion to which the load is input is easily deformed so as to be displaced obliquely downward. Thereby, interference with the urea tank 71 located in the upper side of the center frame 7 and the member (for example, fuel supply pipe | tube 54) located in the front can be suppressed.

  In particular, the center frame 7 of the tank support structure 15 is joined to the lower surface of the floor panel 2 as described above and has a closed cross-sectional structure. The closed cross-section portion of the center frame 7 is shown in FIGS. 14, the cross-sectional area is configured to gradually decrease at the front portion of the center frame 7.

  With this configuration, the center frame 7 can be more easily deformed so that the rear end portion is displaced obliquely downward with the joint portion of the front end portion of the center frame 7 and the upper cross member 12 as a fulcrum when the vehicle is rearwardly supported. The interference between the urea tank 71 and the member located in front of the urea tank 71 can be more effectively suppressed. Further, the space below the front portion of the center frame 7 can be secured larger, and interference with members disposed below (for example, the upper components of the rear wheel suspension device 30) can be easily avoided.

  Needless to say, the present invention is not limited to the above-described embodiment, and changes and improvements can be made without departing from the scope of the invention.

  The present invention relates to an exhaust gas purifying apparatus for purifying exhaust gas from an internal combustion engine of a vehicle using a reducing substance, and relates to a structure for arranging a reducing agent tank in a vehicle, assuming that the reducing agent tank is temporarily damaged. In addition, the reducing agent can be prevented from entering the passenger compartment, the adverse effect on the steering stability of the vehicle can be avoided, and the positional relationship between the fuel tank and the exhaust pipe can be suitably set, such as an automobile. As an arrangement structure when the exhaust gas purification device is arranged in this vehicle, it can be effectively used.

It is a bottom view which shows the lower surface side of the compartment floor of the motor vehicle provided with the exhaust gas purification device which concerns on the 1st Embodiment of this invention. FIG. 2 is a partially enlarged bottom view showing the rear part of the vehicle body in FIG. 1 in an enlarged manner. It is a top view which shows the upper surface side of the said vehicle body floor in the said vehicle body rear part. It is sectional drawing along the AA line in FIG. It is a fragmentary sectional view along the BB line in FIG. It is a fragmentary sectional view along CC line in FIG. It is a fragmentary sectional view in alignment with the DD line in FIG. FIG. 8A is a bottom view showing a urea tank in a normal state, and FIG. 8B is a urea tank at the time of a large collision. FIG. 8C is a bottom view showing the collapse mode of the urea tank at the time of a light collision. It is a partial expanded bottom view which expands and shows the vehicle body rear part in the lower surface side of the vehicle body floor of the motor vehicle provided with the exhaust gas purification apparatus which concerns on the 2nd Embodiment of this invention. FIG. 10 is a partially enlarged bottom view of the rear part of the vehicle body floor, with the power transmission system, the rear wheel suspension system, etc. removed from FIG. 9. FIG. 11 is a partially enlarged bottom view of the rear part of the vehicle body floor, in which a fuel pipe, a urea tank, and the like are further removed from FIG. 10. It is a left view of FIG. It is a fragmentary sectional view along the EE line in FIG. It is explanatory drawing which added a part of rear-wheel suspension apparatus to the partial cross section in alignment with the FF line in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Car body 2 Floor panel 4 Tunnel part 4S Tunnel space 6, 6L, 6R Rear side frame 7 Center frame 9 Rear end panel 12 Upper cross member 14 Lateral member 15 Tank support structure 33 (Sub frame) Rear cross member 33b Back curve part 66 Silencer 68 Exhaust port 70 Exhaust gas purification device 71 Urea tank 73 Cover body 74, 74L, 74R Support band 91 Guide member

Claims (13)

A reducing substance for purifying the components contained in the exhaust gas is generated by pyrolyzing a reducing agent that is less toxic than the reducing substance and flame retardant than the fuel, and the generated reducing substance is used to purify the exhaust gas. In a vehicle equipped with an exhaust purification device that performs
Below the floor panel, a fuel tank that stores the fuel, a reducing agent tank that stores the reducing agent, and an exhaust pipe that extends in the vehicle front-rear direction and has an exhaust port at the rear end are disposed.
The reducing agent tank is disposed behind the fuel tank and at a portion spaced from the exhaust pipe in a vehicle width direction by a predetermined gap.
The reducing agent tank is disposed at the rear part of the vehicle body, and a silencer is provided in the exhaust pipe on the side of the reducing agent tank,
A gap in the vehicle width direction between the reducing agent tank and the exhaust pipe is located immediately after a tunnel portion formed to bulge upward on the floor panel and extending in the vehicle front-rear direction.
Arrangement structure of vehicles of the exhaust purification device you wherein a. A reducing substance for purifying the components contained in the exhaust gas is generated by pyrolyzing a reducing agent that is less toxic than the reducing substance and flame retardant than the fuel, and the generated reducing substance is used to purify the exhaust gas. In a vehicle equipped with an exhaust purification device that performs
Below the floor panel, a fuel tank that stores the fuel, a reducing agent tank that stores the reducing agent, and an exhaust pipe that extends in the vehicle front-rear direction and has an exhaust port at the rear end are disposed.
The reducing agent tank is disposed behind the fuel tank and at a portion spaced from the exhaust pipe in a vehicle width direction by a predetermined gap.
The reducing agent tank is disposed at the rear part of the vehicle body, and a silencer is provided in the exhaust pipe on the side of the reducing agent tank,
When the reducing agent tank and the silencer move forward in front of the gap in the vehicle width direction between the reducing agent tank and the exhaust pipe, the at least one of the reducing agent tank and the silencer is separated from the other in the vehicle width direction. A guide portion having a shape for guiding in a direction to be provided,
Arrangement structure of vehicles of the exhaust purification device you wherein a. The arrangement structure of the exhaust emission control device for a vehicle according to claim 2 , wherein the guide portion has a shape for rectifying running air below the floor panel so as to pass through the gap portion. A reducing substance for purifying the components contained in the exhaust gas is generated by pyrolyzing a reducing agent that is less toxic than the reducing substance and flame retardant than the fuel, and the generated reducing substance is used to purify the exhaust gas. In a vehicle equipped with an exhaust purification device that performs
Below the floor panel, a fuel tank that stores the fuel, a reducing agent tank that stores the reducing agent, and an exhaust pipe that extends in the vehicle front-rear direction and has an exhaust port at the rear end are disposed.
The reducing agent tank is disposed behind the fuel tank and at a portion spaced from the exhaust pipe in a vehicle width direction by a predetermined gap.
A rear end panel connected to a rear end portion of the left and right rear side frames on a lower surface of the floor panel supported by a pair of left and right rear side frames extending in a longitudinal direction of the vehicle body; and the left and right rear sides positioned in front of the rear end panel A structure that can suppress vibration of the floor panel is provided between the cross members that connect the frames,
The reducing agent tank is installed so as to straddle the structure and at least one of the rear side frames.
Arrangement structure of vehicles of the exhaust purification device you wherein a. The said structure is comprised by the vertical frame extended in the vehicle body front-back direction, and the horizontal member extended toward the said one rear side frame from the middle part in the vehicle body front-back direction of this vertical frame. 4. An arrangement structure of an exhaust emission control device for a vehicle according to 4 . 5. The vehicle according to claim 4 , wherein the reducing agent tank is supported by a first band member disposed between the structure and the one rear side frame. Arrangement structure of exhaust purification device. The structure is composed of a vertical frame extending in the longitudinal direction of the vehicle body, and a lateral member extending from a middle portion of the vertical frame in the longitudinal direction of the vehicle body toward the one rear side frame,
The rear end of the first band member is fixed to the rear position of the one rear side frame, while the front end is fixed to a lateral member of the structure.
A second band member having front and rear ends fixed to the front and rear of the vertical frame of the structure is further provided;
The reducing agent tank is supported by the first band member and the second band member,
The arrangement structure of the exhaust emission control device for a vehicle according to claim 6 . The horizontal member of the structure has a substantially U-shaped vertical cross section, and its open side is joined to the lower surface of the floor panel to form a closed cross section. The one rear side of the closed cross section 6. The vehicle exhaust purification device disposition structure according to claim 5 , wherein a gap is provided between the frame side tip and the rear side frame . 6. The exhaust purification of a vehicle according to claim 5 , wherein the cross member is disposed on an upper surface of the floor panel, and a front end portion of a vertical frame of the structure is coupled to the cross member. Device arrangement structure. The vertical frame has a substantially U-shaped vertical cross section, and a closed cross section is formed by joining an opening side of the vertical frame to a lower surface of the floor panel . The closed cross section is formed at a front portion of the vertical frame. The arrangement structure of the exhaust emission control device for a vehicle according to claim 9 , wherein the area of the peripheral shape of the longitudinal section is gradually reduced. The arrangement of the exhaust emission control device for a vehicle according to any one of claims 1 to 10 , wherein the reducing agent is a urea compound. The exhaust gas purification of a vehicle according to any one of claims 1 to 11, wherein the reducing agent tank is covered with a cover body at least approximately the entire surface and the lower surface on the side facing the exhaust pipe. Device arrangement structure. The arrangement of the exhaust emission control device for a vehicle according to claim 12 , wherein the reducing agent tank and the cover body are supported via a support member that allows the vehicle body to swing.

Images