JP2009221884A - Tank arrangement structure for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To attain a tank arrangement structure for a vehicle can reduce wasteful consumption of a reducing agent due to heat and lengthen a refilling cycle by protecting the reducing agent from heat of an exhaust pipe. <P>SOLUTION: The tank arrangement structure is for the vehicle in which a drive unit having a water-cooled engine 15 and a transmission 16 not exceeding a first temperature T1 is arranged under a vehicle compartment floor 6 almost in the center in a vehicle width direction and a selective reduction catalyst 25 is provided for controlling emission of exhaust gas under the action of the reducing agent that reacts at a second temperature T2 exceeding the first temperature T1 and generating a purification component. The exhaust pipe 22 extending from the engine passes under the vehicle compartment floor 6 on a lateral one side of the drive unit and is extended rearward and the tank 11, 41 storing the reducing agent is arranged under the vehicle compartment floor 6 on the other side across the drive unit. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a reducing agent tank arrangement structure in a vehicle including a selective reduction catalyst that purifies exhaust gas using a reducing agent that generates ammonia by, for example, thermal decomposition.

In order to increase the purification efficiency of the NOx reduction catalyst particularly in a diesel engine, the selective reduction catalyst, for example, adds a urea ((NH ₂ ) ₂ CO) aqueous solution into the exhaust pipe upstream of the catalyst, and the added urea aqueous solution is exhausted. NOx is reduced using ammonia generated by thermal decomposition with gas (for example, Patent Document 1).

Here, the tank for storing the reducing agent needs to be protected from a high-temperature heat source such as an exhaust pipe, and needs to be replenished periodically. For this reason, Patent Document 2 describes a structure in which a reducing agent tank is disposed in surplus spaces such as a fender, an engine room, a bumper, and a lower part of a seat.
JP 2004-270609 A JP 2006-242092 A

  However, if the reducing agent tanks are distributed and arranged at various locations in the vehicle as in Patent Document 2, the layout of the reducing agent tank and piping becomes complicated. Moreover, if the reducing agent tank, which is a heavy object, is arranged on the side of the vehicle body such as a fender, the weight distribution of the entire vehicle body may be biased and the turning performance may deteriorate.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to protect a reducing agent from the heat of an exhaust pipe, thereby reducing wasteful consumption of the reducing agent due to heat and extending a replenishment cycle. It is to realize the structure.

  In order to solve the above-described problems and achieve the object, a first embodiment according to the present invention includes a water-cooled engine and a transmission that do not exceed a first temperature at a substantially center in a vehicle width direction below a passenger compartment floor. A vehicle tank disposition structure including a selective reduction catalyst that purifies exhaust gas by the action of a reducing agent that reacts at a second temperature that exceeds the first temperature and generates a purifying component. An exhaust pipe extending from the engine extends rearwardly under the vehicle compartment floor on one of the left and right sides of the drive device, and the reducing agent is provided below the vehicle compartment floor on the other side with the drive device interposed therebetween. A tank for storing was disposed.

  According to the first embodiment, a drive device such as a water-cooled engine, which is managed at a temperature lower than the reaction temperature of the reducing agent based on the exhaust gas temperature, is reduced with an exhaust system (an exhaust purification device such as an exhaust pipe or a catalyst) serving as a heat source. By arranging so as to be sandwiched between the agent tanks, the reducing agent can be protected from the heat of the exhaust system, and the replenishment cycle of the reducing agent can be prolonged. Note that, by reducing the capacity of the reducing agent tank to a capacity that consumes the reducing agent in accordance with a cycle such as oil change or periodic inspection, there is an effect that it is not necessary to increase the labor required for replenishment by the user.

  In the second embodiment, a space is formed between the tank and the drive device, and a propeller shaft extends in the front-rear direction in the space. Thereby, heat transfer can be further suppressed by utilizing the space in which the propeller shaft is disposed.

  In a third aspect, the exhaust pipe includes an exhaust purification device that is heated to the second temperature or higher at a portion that sandwiches the drive device with the tank. Thereby, it is possible to suitably protect the tank from a relatively high temperature portion of the exhaust pipe while increasing the exhaust purification efficiency.

  In the fourth embodiment, a fuel tank is provided below the passenger compartment floor behind the tank and the engine. As a result, the fuel tank is also separated from the relatively high temperature portion of the exhaust pipe, so that the heat damage of the fuel can be suppressed, and the mounted parts are arranged behind the relatively large engine, In particular, the tank can be easily enlarged in the vehicle width direction.

  In the fifth aspect, a boarding / exiting opening having a step portion lower than the passenger compartment floor and a door for opening / closing the boarding / exiting opening are provided on the side of the vehicle body on the side where the tank is disposed in the vehicle. The stepped portion is provided with a non-opening portion that is hidden in a side view of the vehicle body when the door is fully opened, and a replenishing port for supplying the reducing agent to the tank is provided in the non-opening portion. Thereby, it becomes easy to arrange | position near the reducing agent tank of a compartment floor lower part comparatively. Further, since the replenishment port is located near the entrance and exit and is hidden by the entire door, the reductant can be easily replenished while not getting in the way. Furthermore, even if the reducing agent leaks from the replenishing port, it can be prevented from scattering into the passenger compartment floor because of the stepped portion.

  In the sixth embodiment, a fuel supply port for supplying fuel is provided on the side surface of the vehicle body provided with the supply port. Thereby, erroneous injection can be suppressed while arranging the replenishing port and the fueling port on the same side of the vehicle body. In particular, the fourth embodiment is preferable because the reducing agent supply pipe and the oil supply pipe can be shortened.

  In the seventh aspect, the selective reduction catalyst is provided in a rear portion of the exhaust pipe with respect to the engine, a rear end portion of the tank is located rearward of the engine, and the selective reduction catalyst is supplied from the tank. A pipe for supplying the reducing agent to the catalyst extends in the vehicle width direction behind the engine. Thereby, piping can be shortened while laying out the exhaust system without difficulty, and pumping loss can be reduced. In particular, in a vehicle in which compressed air cannot be used to add the reducing agent into the exhaust pipe, pressure loss can be reduced, so that energy saving and downsizing of the pump and integration with the tank can achieve downsizing.

  In an eighth aspect, the reducing agent is a urea aqueous solution in which ammonia is generated by thermal decomposition at the second temperature or higher. Thereby, the urea aqueous solution thermally decomposed at the temperature of the exhaust gas can be protected from the heat source. Further, when applied to the seventh embodiment, even if the urea aqueous solution is frozen at the extreme cold, the clogged pipe can be quickly thawed with energy saving, and the engine can be started quickly.

  According to the present invention, by protecting the reducing agent from the heat of the exhaust pipe, wasteful consumption of the reducing agent due to heat can be reduced, and the replenishment cycle can be prolonged.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  The embodiment described below is an example as means for realizing the present invention, and the present invention can be applied to a modified or modified embodiment described below without departing from the spirit of the present invention.

[First Embodiment]
FIG. 1 is a side view of a vehicle to which a tank arrangement structure according to a first embodiment of the present invention is applied. FIG. 2 is a bottom view showing the tank arrangement structure of the vehicle according to the first embodiment of the present invention. 3 is a cross-sectional view taken along line AA in FIG. 2, and FIG. 4 is a side perspective view seen from the right side of the vehicle body in FIG. FIG. 5 is a cross-sectional view of the supply piping.

  As shown in FIGS. 1 to 4, the vehicle 1 according to the present embodiment is ridden on the side of the vehicle body between the front wheel 2 and the rear wheel 3, represented by a minivan, etc., with respect to the second and subsequent rows of passengers. For this purpose, an entrance / exit 4 is opened, and a sliding door 5 is slidable in the front-rear direction for opening / closing the entrance 4. FIG. 1 shows a state in which the slide door 5 is fully opened.

  A floor tunnel portion 7 is provided at a substantially center L in the vehicle width direction of the passenger compartment floor panel 6, and front seats 8 are disposed on the passenger compartment floor panels 6 on both sides in the vehicle width direction across the floor tunnel portion 7. The

  On the side surface of the vehicle body where the entrance / exit 4 is located, a step 10 having a lower step than the vehicle compartment floor panel 6 and the vehicle body floor panel 9 below it is provided. The step 10 is provided with a non-opening portion 10a that is covered and hidden by the front end of the vehicle body when the sliding door 5 is fully opened, and a supply port for supplying the reducing agent to the reducing agent tank 11 in the non-opening portion 10a. 12 is arranged. Further, an oil supply port 14 for supplying fuel to the fuel tank 13 is disposed on the same side of the vehicle body (B pillar 1 </ b> A) in front of the supply port 12.

  In the center L in the vehicle width direction in front of the lower part of the passenger compartment floor panel 6, there is provided a drive unit comprising an engine 15 and a transmission 16 that are temperature-controlled by water cooling so as not to exceed the first temperature T1, and a shift of the drive unit A propeller shaft 17R extending rearward from the machine 16 is disposed. The vehicle of this embodiment is a so-called front engine rear drive (FR) vehicle in which the rear wheel 3 is driven via a rear wheel differential 18R and a rear wheel drive shaft 19R by a rear wheel propeller shaft 17R extending rearward from the transmission 16. is there. Reference numeral 37 denotes a suspension of the rear wheel 3. The engine 15 is described as an example applied to a diesel engine. Needless to say, the engine 15 can also be applied to other internal combustion engines such as gasoline (excluding air cooling) as long as the vehicle is equipped with a selective reduction catalyst. Yes.

  In addition, a pair of side frames 20 extend on both sides in the vehicle width direction at the lower part of the vehicle body floor panel 9, and the space below the vehicle body floor panel 9 between the drive device and one of the left and right side frames 20 is provided in the space. An exhaust pipe 22 extending rearward from the engine 15 via the exhaust manifold 21 across the lower part of the engine 15 in the vehicle width direction is disposed, and an exhaust purification device 24 is connected to the exhaust pipe 22 near the lower portion of the cross member 23. A selective reduction catalyst 25 that purifies exhaust gas by a reducing agent that reacts at a second temperature T2 higher than the first temperature T1 is connected to the downstream side of the exhaust purification device 24. The exhaust purification device 24 is composed of, for example, a diesel particulate removal device (DPF) or an oxidation catalyst. The exhaust purification device 24 and the selective reduction catalyst 25 are connected in series to the exhaust pipe 22. Further, a silencer 26 is connected to the downstream end of the exhaust pipe 22, and a spare tire 27 is supported at the lower part of the vehicle body floor panel 9 near the silencer 26.

  The selective reduction catalyst 25 is disposed behind the engine 15 in the exhaust pipe 22. The exhaust purification device 24 is disposed on the opposite side of the replenishment tank 11 with the transmission 16 interposed therebetween, and the selective reduction catalyst 25 is disposed on the opposite side of the fuel tank 13 with the rear wheel propeller shaft 17R interposed therebetween. The exhaust purification device 24 and the selective reduction catalyst 25 are supported on the lower portion of the side frame 20 by connecting a stay 28 provided on each of them to a mounting arm 29 provided on the vehicle body floor panel 9 via a rubber 30.

  Further, a reducing agent tank 11 for storing a reducing agent is disposed above the cross member 23 below the passenger compartment floor panel 6 between the drive devices 15 and 16 and the side frame 20 opposite to the exhaust pipe 22. A fuel tank 13 is disposed behind the drive devices 15 and 16 and the reducing agent tank 11. In other words, the rear wheel propeller shaft 17R is disposed in a space formed in the center L in the vehicle width direction between the reducing agent tank 11 and the fuel tank 13 and the exhaust pipe 22, and extends rearward. The exhaust purification device 24 and the selective reduction catalyst 25 are disposed on the opposite side of the reducing agent tank 11 and the fuel tank 13 with the engine 15 and the transmission 16 interposed therebetween. As a result, since the drive device including the engine 15 and the transmission 16 is disposed between the reducing agent tank 11 and the selective reduction catalyst 25, the exhaust purification device 24 and the selective reduction catalyst 25 that are relatively high temperature portions of the exhaust pipe 22. Thus, the reducing agent tank 11 can be appropriately protected from the heat. Further, since the fuel tank 13 is also separated from the relatively high temperature portion of the exhaust pipe 22, it is possible to suppress the heat damage of the fuel and to be disposed behind the relatively large engine 15 among the mounted components. In particular, it becomes easy to enlarge the tank in the vehicle width direction.

  The replenishing port 12 and the refueling port 14 are disposed on the side of the vehicle body on the reducing agent tank 11 and the fuel tank 13 side, and are connected to each tank by a replenishing piping 12a and a refueling piping 14a, respectively. Thereby, erroneous injection can be suppressed while the replenishing port 12 and the fueling port 14 are disposed on the same side of the vehicle body. In particular, in the configuration in which the fuel tank 13 is disposed behind the reducing agent tank 11, the refilling pipe 12a and the oil supply pipe 14a can be shortened, which is preferable.

  The reducing agent tank 11 has at least a rear end portion located behind the engine 15, and a supply pipe 11 a that supplies the reducing agent from the reducing agent tank 11 to the selective reduction catalyst 25 extends in the vehicle width direction behind the engine 15. Established. With this configuration, it is possible to shorten the piping while laying out the exhaust purification device without difficulty, and to reduce the pumping loss of the pump / heater unit 33. Especially in small vehicles (other than trucks and buses) that cannot use compressed air to inject the reducing agent into the exhaust pipe 22, pressure loss can be reduced, resulting in energy saving and downsizing of the pump and integration with the tank. Can be achieved.

  The selective reduction catalyst 25 has a function of purifying exhaust gas using a reducing agent that is thermally decomposed at a high temperature and generates ammonia as a purification component. The reducing agent is ammonia at a second temperature T2 (about 150 ° C.). This is an aqueous urea solution that generates water. Note that ammonia is suitable as the NOx purification component, but is not limited thereto, and other reducing agents that generate HC, CO, and the like by thermal decomposition may be used. Since the thermal decomposition temperature of the urea aqueous solution is approximately 150 ° C., exceeding 120 ° C. (first temperature T 1) can sufficiently insulate the exhaust pipe 22 by the rare water-cooled engine 15 and the transmission 16. Therefore, the urea solution decomposed at the temperature of the exhaust gas can be protected from the exhaust heat. The freezing temperature of the aqueous urea solution is −11 ° C. with a urea 32.5% concentration (trade name: AdBlue). Therefore, in the configuration in which the reducing agent tank 11 is protected from the heat of the exhaust pipe 22 by the water-cooled engine 15 and the transmission 16 as in this example, even if the urea liquid freezes at extremely cold temperatures, the clogging of the pipe is quickly thawed with energy saving. And start the engine quickly.

  In addition, an injector 31 that is connected to the supply pipe 11 a and injects the reducing agent into the exhaust pipe 22 is disposed immediately upstream of the selective reduction catalyst 25 in the exhaust pipe 22.

  The reducing agent tank 11 is made of resin, and is supported on the side frame 20 and the lower part of the vehicle body floor panel 9 by an attachment band 32. Inside the reducing agent tank 11 is disposed a pump / heater unit 33 including a pump for pumping the reducing agent to the injector 31 and a heater for raising the temperature of the reducing agent.

  The supply pipe 11 a for supplying the reducing agent is made of resin, and as shown in FIG. 5, as shown in FIG. 5, the forward pipe 34 for sending the temperature raising agent from the pump / heater unit 33 to the injector 31, and the injector 31 from the injector 31 to the pump / heater unit 33. A return pipe 35 for returning the warming agent and a reducing agent supply pipe 36 surrounding the forward pipe 34 and the return pipe 35 are provided.

  As described above, the present invention is characterized by using a water-cooled engine, which tends to be considered as a heat source, as a heat insulating material having a cooling capacity, paying attention to the fact that the water-cooled engine does not easily reach a temperature higher than the boiling point of the cooling water. In a specific example, a drive device composed of a water-cooled engine 15 and a transmission 16 that are temperature-controlled lower than the exhaust temperature is sandwiched between the exhaust pipe 22 and the reducing agent tank 11, thereby reducing the reducing agent from the heat of the exhaust pipe 22. It is possible to protect the reducing agent in the tank 11, thereby suppressing a useless reaction of the reducing agent and extending the supply cycle. It should be noted that the labor of the user is not increased by matching the tank capacity to the reducing agent consumption in the cycle such as oil change and periodic inspection. The engine cooling water overheating temperature cannot be generally specified depending on the type of cooling water, but it is 120 ° C or less. Since the transmission is cooled by oil or the like without a high-temperature heat source, it is rare to greatly exceed 100 ° C. .

  Further, since the replenishment port 12 to the reducing agent tank 11 is provided in the non-opening portion 10a that is hidden in the side view of the vehicle body when the slide door 5 is fully opened in step 10, a comparison with the reducing agent tank 11 provided at the lower part of the vehicle body floor panel 9 is made. Arrangement near the target becomes easy. Further, since the replenishing port 12 is close to the entrance / exit 4, it is easy to replenish the reducing agent, but does not obstruct getting on / off. Furthermore, even if the reducing agent leaks out from the replenishing port 12, the step 10 can prevent the scattering to the vehicle compartment floor panel 6.

[Second Embodiment]
FIG. 6 is a side view of a vehicle to which the tank arrangement structure of the second embodiment according to the present invention is applied. FIG. 7 is a bottom view showing a tank arrangement structure for a vehicle according to a second embodiment of the present invention. FIG. 8 is a cross-sectional view taken along the line BB in FIG.

  The first embodiment is a so-called FR vehicle in which the rear wheel propeller shaft 17R extends rearward from the transmission 16 to drive the rear wheel 3, and the replenishment port 12 is disposed in the non-opening portion 10a at the rear of the step 10. It had been. On the other hand, in the second embodiment, the front wheel 2 is driven via the front wheel differential 18F and the front wheel drive shaft 19F by the front wheel propeller shaft 17F extending forward from the transmission 16, and the rear wheel extends rearward from the transmission 16. This is a structure for a so-called four-wheel drive vehicle in which the rear wheel 3 is driven by the wheel propeller shaft 17R via the rear wheel differential 18R and the rear wheel drive shaft 19R. In addition, although this embodiment demonstrates the example applied to a four-wheel drive vehicle, it cannot be overemphasized that it can apply also to what is called a front engine front drive (FF) vehicle.

  As shown in FIGS. 6 to 8, in the present embodiment, the non-opening portion 10 b hidden by the B pillar 1 </ b> A at the front of the step 10 is disposed below the fuel filler port 14 so that the replenishing port 42 faces upward. Established. The replenishing port 42 is connected to a concave portion 43 that is formed in the front portion of Step 10 and opens upward, and the concave portion 43 can be opened and closed by a lid 44. In addition, a gap 45 is formed between the bottom surface of the recess 43 and the supply pipe 41a, and the reducing agent leaked when the reducing agent is replenished is discharged from the gap 45 to the outside.

  According to the present embodiment, in addition to the effects of the first embodiment, the front wheel propeller shaft 17F is disposed in the space between the reducing agent tank 41 and the drive device and extends forward. Heat transfer from the exhaust pipe 22 to the reducing agent tank 41 can be suppressed using the space in which the shaft 17F is disposed.

  For other configurations, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

1 is a side view of a vehicle to which a tank arrangement structure according to a first embodiment of the present invention is applied. It is a bottom view which shows the tank arrangement structure of the vehicle of 1st Embodiment which concerns on this invention. It is AA sectional drawing of FIG. FIG. 3 is a side perspective view seen from the right side of the vehicle body in FIG. 2. It is sectional drawing of supply piping. It is a side view of the vehicle with which the tank arrangement | positioning structure of 2nd Embodiment which concerns on this invention is applied. It is a bottom view which shows the tank arrangement structure of the vehicle of 2nd Embodiment which concerns on this invention. It is BB sectional drawing (a) of FIG. 7, and the enlarged view (b) of the C section.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Car body 1A B pillar 2 Front wheel 3 Rear wheel 4 Entrance / exit 5 Sliding door 6 Car room floor panel 7 Floor tunnel part 8 Front seat 9 Car body floor panel 10 Steps 11, 41 Reductant tank 12, 42 Supply port 13 Fuel tank 14 Refueling Port 15 Water-cooled engine 16 Transmission 17F Front wheel propeller shaft 18F Front wheel differential 19F Front wheel drive shaft 17R Rear wheel propeller shaft 18F Rear wheel differential 19F Rear wheel drive shaft 20 Side frame 21 Exhaust manifold 22 Exhaust pipe 23 Cross member 24 Exhaust purification device 25 Selection Reduction catalyst 26 Silencer 27 Spare tire 28 Stay 29 Mounting arm 30 Rubber 31 Injector 32 Mounting band 33 Pump / heater unit 34 Outward pipe 35 Return pipe 36 Reducing agent supply pipe 37 Suspension Pensions

Claims (8)

A drive unit having a water-cooled engine and a transmission that does not exceed the first temperature is disposed in the center of the vehicle width direction below the passenger compartment floor, and reacts and purifies at a second temperature that exceeds the first temperature. A tank arrangement structure of a vehicle including a selective reduction catalyst that purifies exhaust gas by the action of a reducing agent that generates a component,
An exhaust pipe extending from the engine extends rearward under the passenger compartment floor on the left and right sides of the drive device,
A tank arrangement structure for a vehicle, wherein a tank for storing the reducing agent is arranged below the vehicle compartment floor on the other side across the drive device.   The vehicle tank arrangement structure according to claim 1, wherein a space is formed between the tank and the driving device, and a propeller shaft extends in the front-rear direction in the space.   3. The vehicle tank arrangement structure according to claim 1, wherein the exhaust pipe includes an exhaust purification device that is heated to the second temperature or higher at a portion that sandwiches the drive device with the tank. 4.   The tank arrangement structure for a vehicle according to claim 3, wherein a fuel tank is provided below the passenger compartment floor behind the tank and the engine. On the side of the vehicle body on the side where the tank is disposed in the vehicle, there is provided an entrance and exit having a step portion lower than the passenger compartment floor, and a door for opening and closing the entrance and exit,
The step portion is provided with a non-opening portion that is hidden in a side view of the vehicle body when the door is fully opened, and a supply port for supplying the reducing agent to the tank is provided in the non-opening portion. 5. A tank arrangement structure for a vehicle according to any one of 1 to 4.   6. The tank arrangement structure for a vehicle according to claim 5, wherein an oil supply port for supplying fuel is provided on a side surface of the vehicle body provided with the supply port. The selective reduction catalyst is provided in a rear portion of the exhaust pipe with respect to the engine,
A rear end portion of the tank is located behind the engine, and a pipe for supplying the reducing agent from the tank to the selective reduction catalyst extends in the vehicle width direction behind the engine. The tank arrangement structure for a vehicle according to any one of claims 1 to 6.   The vehicle tank arrangement structure according to any one of claims 1 to 7, wherein the reducing agent is a urea aqueous solution that generates ammonia by thermal decomposition at the second temperature or higher.

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