JP2018091206A - Atmosphere opening structure for tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize an atmosphere opening motion, relating to an atmosphere opening structure for a tank.SOLUTION: An atmosphere opening structure 1 is provided to a tank 9 in which an additive for cleaning an exhaust gas from an engine is stored. The atmosphere opening structure 1 is connected with one end of an atmosphere release pipe 2. The other end 3 of the atmosphere release pipe 2 is open to the atmosphere inside a wheel house 15 of a vehicle.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an atmosphere opening structure of a tank in which an additive for exhaust gas purification is stored.

  2. Description of the Related Art Conventionally, a vehicle equipped with an exhaust gas purification system that reduces and purifies exhaust gas components is equipped with an additive tank having a reducing action on a substance to be purified. When the purification target substance is nitrogen oxide (NOx), additives such as an aqueous urea solution and an aqueous ammonia solution are stored in the tank. In addition, for example, it has been proposed to set the tank disposition position below the floor of the vehicle (see Patent Document 1). With such a layout, a space in the vehicle compartment is secured, and a decrease in cabin comfort due to the leakage of the additive is prevented.

Japanese Patent No. 4826612

  By the way, a technique is known in which an atmosphere release valve (ventilation valve) is provided in an additive tank to maintain the internal pressure in the vicinity of atmospheric pressure. The air release valve functions to balance the tank internal pressure and the external air pressure while maintaining liquid tightness with respect to the additive stored in the tank and external moisture. On the other hand, in a tank mounted on a vehicle, the position where the atmosphere is released by the atmosphere release valve may be a problem.

  For example, when the air is released to the space on the lower surface side of the vehicle (the gap between the road surface and the vehicle body), the pressure acting on the air release valve fluctuates due to the influence of traveling wind, and the opening / closing operation Stability can be reduced. Similarly, when the atmosphere in the exhaust passage is opened to the atmosphere, there is a possibility that the atmosphere release valve is opened and closed in accordance with the exhaust pressure fluctuation. On the other hand, if the vehicle interior is opened to the atmosphere, pressure fluctuations associated with vehicle travel as described above are suppressed, but there is a risk that cabin comfort will be reduced due to leakage of the vaporized component of the additive. Therefore, it is desirable that the air release target is outside the passenger compartment.

  One of the objects of the present case was created in light of the above-described problems, and is to provide a tank open-to-air structure that stabilizes the open air operation. It should be noted that the present invention is not limited to this purpose, and is an operational effect that is derived from each configuration shown in “Mode for Carrying Out the Invention” to be described later. Can be positioned as a purpose.

(1) The tank atmosphere release structure disclosed herein includes an atmosphere release valve provided in a tank in which an additive for purifying engine exhaust gas is stored. In addition, an atmosphere release pipe having one end connected to the atmosphere release valve and the other end opened to the atmosphere inside the wheel house of the vehicle is provided.
(2) It is preferable to provide a splash shield that is fixed to the tire side from the wheel house inner inside the wheel house. In this case, it is preferable that the other end of the atmosphere release pipe is opened to the atmosphere in a space surrounded by the wheel house inner and the splash shield.

(3) It is preferable that a leveling pipe connected to the tank and opened to the atmosphere when the tank is replenished with the additive to define an upper limit liquid level is provided. In addition, it is preferable to include a chamber which is interposed in the middle of the leveling pipe and serves as a pool of the additive when the additive is replenished beyond the upper limit liquid level.
(4) It is preferable that the other end of the atmosphere release pipe is opened to the atmosphere in a space surrounded by the wheel house inner, the splash shield, and the chamber.
(5) It is preferable that the other end of the atmospheric open pipe is fixed to the chamber.

  By opening the front end of the atmosphere release pipe of the tank inside the wheel house, it is possible to suppress blockage of the atmosphere release pipe due to rain, mud, or the like while improving cabin comfort. Further, since the inside of the wheel house is not easily affected by traveling wind or exhaust flow, the operating state of the air release valve can be stabilized.

1 is a perspective view of a vehicle to which an atmosphere opening structure for a tank according to an embodiment is applied. It is a longitudinal cross-sectional view of a wheel house. It is a schematic diagram for demonstrating the structure of a tank. It is a fragmentary sectional view of a chamber. It is a see-through | perspective side view of a wheel house.

  With reference to the drawings, an atmosphere opening structure of a tank as an embodiment will be described. Note that the embodiment described below is merely an example, and there is no intention to exclude various modifications and technical applications that are not explicitly described in the following embodiment. Each configuration of the present embodiment can be implemented with various modifications without departing from the spirit thereof. Further, they can be selected as necessary, or can be appropriately combined.

[1. Constitution]
The tank atmosphere opening structure of this embodiment is applied to the vehicle 10 shown in FIG. Under the floor on the rear side of the vehicle 10, the tank 9 is fixed to the vehicle body. The tank 9 is a resin container for storing additives (for example, urea aqueous solution, ammonia aqueous solution, etc.) used in a urea SCR system (Urea Selective Catalytic Reduction System) for exhaust purification. In the left rear fender of the vehicle 10, an oil supply port for replenishing fuel and a water injection port 7 for replenishing additives are disposed adjacent to each other. A water injection pipe 8 is connected between the water injection port 7 and the tank 9 in a communicating state, and the leveling pipe 4 is routed so as to run in parallel therewith.

  The leveling pipe 4 is a pipe that is opened to the atmosphere when the additive is replenished and defines the upper limit liquid level of the additive in the tank 9. The lower end of the leveling pipe 4 is opened to the internal space of the tank 9 at the upper liquid level, and the upper end is connected to the water inlet 7. A water injection cap 20 is attached to the water injection port 7 so as to be freely opened and closed. In the state where the water injection cap 20 is attached, the water injection port 7 is closed, and the upper end of the leveling pipe 4 is closed to the outside of the vehicle 10. On the other hand, when the water injection cap 20 is removed, the upper end of the leveling pipe 4 is opened to the atmosphere.

  As shown in FIG. 2, the water injection port 7 is fixed to a box-shaped casing attached to the outer panel 11. The leveling pipe 4 and the water injection pipe 8 are extended downward from the water injection port 7. In the present embodiment, the leveling pipe 4 and the water injection pipe 8 are routed inside the rear wheel house 15. The wheel house 15 is an arch-shaped portion that covers the upper surface of the tire 19 (rear wheel), and is formed by combining, for example, a wheel house inner 16 and a wheel house outer 17.

  The splash shield 18 is a high-rigidity, high-strength resin molded product having a shape along the inner surface shape of the wheel house 15, and is fixed to the wheel house 15 with bolts, nuts, screws, clip members, and the like. The splash shield 18 is provided closer to the tire 19 (inner side) than the wheel house inner 16 and the wheel house outer 17, and functions to protect the vehicle body from pebbles and muddy water splashed by the tire 19.

  The leveling pipe 4 and the water injection pipe 8 are extended to the lower side than the side member 13 of the vehicle 10 on the tire 19 side of the wheel house inner 16. The leveling pipe 4 and the water injection pipe 8 that have passed through the lower side of the side member 13 are connected to a tank 9 disposed below the floor panel 14.

  FIG. 3 is a diagram schematically showing the structure of the tank 9. The water injection pipe 8 is connected to the side surface of the tank 9. Further, the leveling pipe 4 is connected to the upper side of the tank 9, and is opened to the inside of the tank 9 at a position higher than at least a connection portion between the water injection pipe 8 and the tank 9. The additive stored in the tank 9 is sucked up by the additive pump 21 at an appropriate timing according to the operating state of the engine mounted on the vehicle 10 and supplied to the additive injector 23 through the additive pipe 22. . The additive injector 23 is arranged on the upstream side of the NOx selective reduction catalyst interposed on the exhaust passage.

  An atmosphere release valve 1 (ventilation valve) for maintaining the internal pressure of the tank 9 near atmospheric pressure is attached to the upper side of the tank 9. The air release valve 1 functions to balance the internal pressure and the external pressure of the tank 9 while maintaining liquid tightness with respect to the additive stored in the tank 9 and external moisture. Further, one end of an atmosphere release pipe 2 is connected to the atmosphere release valve 1, and the tip 3 on the other end side is opened to the atmosphere inside the wheel house 15. The position of the air release valve 1 is set in the vicinity of the uppermost portion of the tank 9 so as not to be submerged below the liquid level even when the vehicle body posture is inclined.

  A leveling pipe 4 is attached to a position on the upper surface of the tank 9 that is slightly below the air release valve 1. The leveling pipe 4 is fixed in a posture orthogonal to the upper surface of the tank 9. The height of the lower end of the leveling pipe 4 is set to a position that is at least higher than the height of the connecting portion between the water injection pipe 8 and the tank 9. A hollow container-like chamber 5 is interposed in the middle of the leveling pipe 4 on the pipe line. The chamber 5 is a portion that becomes a “puddle” in which the additive that has flowed back through the leveling pipe 4 during the replenishment of the additive is retained. That is, the internal space of the chamber 5 functions as a space for storing an excessive amount of additive when the additive continues to be replenished even when the liquid level reaches the upper limit liquid level during replenishment of the additive. .

  The arrangement position of the chamber 5 is preferably set in the vicinity of the water inlet 7. In the present embodiment, the position in the height direction of the chamber 5 is set so that the “water injection amount confirmation height” indicated by a two-dot chain line in FIG. The water injection amount confirmation height is a liquid level height set inside the water injection pipe 8. As shown in FIG. 3, the horizontal sectional area of the chamber 5 at the water injection amount confirmation height is set larger than the horizontal sectional area of the water injection pipe 8 at the water injection amount confirmation height. Thereby, when the additive is replenished at a constant speed, the rising speed of the liquid level inside the water injection pipe 8 is decelerated in the vicinity of the water injection amount confirmation height. Therefore, it becomes easy to confirm that the liquid level has reached the water injection amount confirmation height, and the occurrence of overflow during the replenishment operation of the additive is prevented.

  As shown in FIG. 4, the outer surface of the chamber 5 is provided with a clip 6 for fixing the upper end side of the atmosphere release pipe 2. The clip 6 is formed with a semi-cylindrical dent that can come into surface contact with the outer peripheral surface of the air release tube 2. The air release pipe 2 is elastically supported by the clip 6 in a posture sandwiched between the dents. The clip 6 of the present embodiment is made of resin and is integrally formed (integrated molding) with the chamber 5 that is also a resin molded product. Thereby, the relative position of the tip 3 of the air release pipe 2 is fixed to a certain degree with respect to the leveling pipe 4 and the chamber 5. In addition to the clip 6, a bracket (not shown) for fixing the chamber 5 to the wheel house inner 16 is formed on the outer surface of the chamber 5.

  As shown in FIG. 2, the position of the tip 3 of the atmosphere release pipe 2 is open to the atmosphere at least inside the wheel house 15 of the vehicle 10, and preferably in the space surrounded by the wheel house inner 16 and the splash shield 18. Opened. As shown in FIG. 5, the tip 3 of the air release tube 2 of the present embodiment is open to the atmosphere in a space surrounded by the wheel house inner 16, the splash shield 18, and the chamber 5. In addition, the chamber 5 in which the tip 3 is supported is disposed on the rear side of the position where the water injection pipe 8 extending directly downward from the water injection port 7 is bent rearward along the circumferential surface of the tire 19. The Therefore, the position of the tip 3 in the side view of the vehicle 10 is obliquely upward behind the tire 19.

[2. Action, effect]
[1] By opening the tip 3 of the air release pipe 2 of the tank 9 to the atmosphere inside the wheel house 15, it is possible to suppress blockage of the air release pipe 2 due to rain, mud, etc. while improving the cabin comfort. Can do. Moreover, since the inside of the wheel house 15 is not a vehicle interior space, even if the vaporized component of the additive leaks, the vehicle interior environment is not affected. Therefore, the cabin comfort can be improved. On the other hand, since the inside of the wheel house 15 is less affected by the traveling wind and exhaust flow than the lower surface of the vehicle 10, pressure fluctuations associated with traveling of the vehicle 10 are less likely to affect the operation of the air release valve 1. The operating state of the air release valve 1 can be stabilized.

  [2] Further, by disposing the tip 3 of the atmosphere release pipe 2 in a space surrounded by the wheel house inner 16 and the splash shield 18, the tip 3 can be protected by the wheel house inner 16 and the splash shield 18. . Thereby, it is possible to prevent water and mud splashed from the tire 19 from being scattered toward the tip 3 of the air release pipe 2. Therefore, it is possible to effectively prevent the air release pipe 2 from being blocked.

  [3] Furthermore, by disposing the tip 3 of the atmosphere release pipe 2 in a space surrounded by the three members of the wheel house inner 16, the splash shield 18, and the chamber 5, the protection can be further improved, and the atmosphere is released. The blockage of the tube 2 can be prevented more reliably. Further, as shown in FIG. 5, the position of the tip 3 of the air release pipe 2 is obliquely above and behind the tire 19, so that it is not easily affected by water or mud splashed from the tire 19. Therefore, it is possible to effectively prevent the air release pipe 2 from being blocked.

  [4] In a structure in which the tip 3 of the atmosphere release pipe 2 is fixed to the wheel house inner 16, a bracket for connecting the wheel house inner 16 and the atmosphere release pipe 2 must be prepared. On the other hand, if a structure in which the tip 3 of the atmosphere release pipe 2 is fixed to the chamber 5 is employed, the clip 6 can be formed integrally with the chamber 5. Therefore, the number of parts can be reduced and the product cost can be reduced.

  [5] In addition, by interposing the chamber 5 on the pipe of the leveling pipe 4, it is possible to retain an excessive amount of additive in the chamber 5 at the time of replenishing the additive exceeding the upper limit liquid level. Thereby, the rising speed of the liquid level which flows back through the inside of the leveling pipe 4 and the water injection pipe 8 during the water injection operation can be reduced near the water injection amount confirmation height. Therefore, it is possible to prevent the overflow from occurring during the additive replenishment operation.

[3. Modified example]
In the above-described embodiment, the tank 9 of the urea SCR system has been described in detail, but the type of additive stored in the tank 9 is not limited to urea water. In an exhaust purification system using a NOx selective reduction catalyst, ammonia may be used instead of urea. Therefore, the tank 9 can be used as an additive container for storing an aqueous ammonia solution. In addition, in an exhaust purification system using DPF (diesel particulate filter), hydrocarbons (HC, unburned fuel) are injected into the exhaust pipe to promote combustion of PM (particulate matter). Sometimes. In this case, the tank 9 can also be used as an additive container for storing fuel.

1 Air release valve 2 Air release pipe 3 Tip (other end)
4 Leveling pipe 5 Chamber 6 Clip 7 Water inlet 8 Water inlet pipe 9 Tank 10 Vehicle 15 Wheel house 16 Wheel house inner 17 Wheel house outer 18 Splash shield

Claims (5)

An air release valve provided in a tank in which an additive for purifying engine exhaust is stored;
An atmosphere release pipe having one end connected to the atmosphere release valve and the other end opened to the atmosphere inside the wheel house of the vehicle;
A structure for opening the tank to the atmosphere. A splash shield fixed to the tire side from the wheel house inner inside the wheel house,
The atmosphere opening structure of the tank according to claim 1, wherein the other end of the atmosphere releasing pipe is opened to the atmosphere in a space surrounded by the wheel house inner and the splash shield. A leveling pipe connected to the tank and opened to the atmosphere when the tank is replenished with the additive to define an upper limit liquid level;
A chamber which is interposed in the middle of the leveling pipe and becomes a pool of the additive when the additive is replenished beyond the upper limit liquid level. The open air structure of the described tank. 4. The tank according to claim 3, wherein the other end of the atmosphere release pipe is opened to the atmosphere in a space surrounded by the wheel house inner, the splash shield, and the chamber. Open to the atmosphere. The atmosphere opening structure of the tank according to claim 4, wherein the other end of the atmosphere releasing pipe is fixed to the chamber.

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