JP2014125025A - Fuel tank structure for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce inner pressure in a fuel tank properly when a liquid level of fuel reaches to a tip end of a breather pipe regardless of the posture of a vehicle.SOLUTION: On an opening end of a breather pipe for exhausting air in a fuel tank, plural grooves 21 are formed. By relative positional relation between liquid level 11F of fuel and the grooves 21, when pressure of an air layer in the fuel tank 2 is adjusted, the plural grooves 21 exhaust air surely, regardless of the state of the liquid level 11F.

Description

  The present invention relates to a structure of a fuel tank for a vehicle provided with a breather pipe that adjusts the pressure of an air layer in the fuel tank by performing air venting during refueling.

  A fuel tank for storing fuel such as gasoline or light oil is mounted on the vehicle. The fuel tank is provided with a fuel supply pipe that supplies fuel and a breather pipe that allows air in the fuel tank to escape during refueling. For example, one end of the breather pipe is connected to the filler neck of the fuel supply pipe, and the tip of the breather pipe is open to the top of the fuel tank.

  When fuel is supplied into the fuel tank through the fuel supply pipe, the liquid level of the fuel rises and air inside the fuel tank is discharged from the breather pipe. When the liquid level of the fuel rises and reaches the tip of the breather pipe, the air discharged to the outside is greatly reduced and the internal pressure of the fuel tank rises rapidly, and at the same time, the air cannot be vented. In this state, it becomes impossible to put fuel into the tank, the liquid level in the oil supply pipe rises, and it is determined that the tank is full, and fuel supply is stopped.

  At the moment when fuel supply is stopped, the liquid level of the fuel in the fuel tank is in a wavy state due to the influence of the fuel supply flow accompanying the fuel supply. For this reason, the tip of the breather pipe is blocked by the liquid level, making it impossible to put fuel into the tank. When the wave valleys reach or reach the tip of the breather pipe and are vented again through the breather pipe, the liquid level in the oil supply pipe is lowered, and additional fuel can be supplied.

  Immediately after the fuel level rises and reaches the tip of the breather pipe during refueling, the internal pressure of the fuel tank suddenly increases. If additional fuel is supplied in this state, the internal pressure of the fuel tank is further increased, the fuel in the fuel supply pipe is returned, and the liquid level in the fuel supply pipe is further increased by the fuel for the additional fuel supply. There was a risk that the fuel would erupt outside.

  Therefore, compared to the cross section of the breather pipe perpendicular to the axis, the area of the opening at the tip of the breather pipe is expanded up and down, and when the fuel level reaches the tip of the breather pipe, the fuel level is increased. Conventionally, a technique has been proposed in which the area of the tip of the pipe is widened so that the air in the tank can be vented at an early stage (for example, Patent Document 1).

  By preventing the wave of the fuel level from completely blocking the tip of the breather pipe, it is possible to vent the air inside the fuel tank after refueling by increasing the area of the opening. Go down. As a result, the fuel level of the fuel pipe can be lowered, and even if additional fuel is supplied, the fuel is returned and is not ejected outside.

  However, if the area of the opening at the tip of the breather pipe is increased vertically, the time from when the tip of the breather pipe touches the liquid level of the fuel until it is completely blocked increases the efficiency of refueling. In some cases, regulation of the fuel level in the fuel tank (regulation of full tank capacity) cannot be performed stably and accurately.

  The fuel station has an inclined road surface so that spilled fuel flows and collects at a predetermined location. For this reason, depending on the stop position of the vehicle when refueling, the vehicle may incline in an unspecified state, and even if the area of the opening at the tip of the breather pipe is expanded only in one direction, depending on the state of inclination of the vehicle The fuel level completely closed the tip of the breather pipe, and there was a risk that air could not be vented.

  In addition, the state of vehicle inclination becomes unstable depending on the loading situation of the vehicle, and there is a possibility that the liquid level of the fuel suddenly blocks the tip of the breather pipe and the air cannot be vented.

  Therefore, even if the area of the opening at the tip of the breather pipe is expanded only in one direction, the internal pressure of the fuel tank may increase rapidly depending on the state of inclination of the vehicle. In addition, when the air cannot be vented and additional fuel is supplied, the fuel is returned inside the oil supply pipe due to the increased internal pressure of the fuel tank, and the liquid level in the oil supply pipe is further increased by the amount of additional fuel. In fact, there was a possibility that fuel might be ejected to the outside.

JP 2012-224133 A

  The present invention has been made in view of the above situation, and suppresses a rapid increase in the internal pressure of the fuel tank when the liquid level of the fuel reaches the tip of the breather pipe regardless of the position of the vehicle, Provides a fuel tank structure for vehicles that can prevent external jetting of fuel that flows back through the fuel supply pipe due to the increased internal pressure of the fuel tank during additional refueling by reliably venting air and properly reducing the internal pressure The purpose is to do.

  According to a first aspect of the present invention, there is provided a fuel tank structure for a vehicle according to a first aspect of the present invention, comprising: a fuel refueling pipe that supplies fuel into the fuel tank; and an open end that opens inside the fuel tank. A breather pipe that discharges air in the fuel tank and adjusts the pressure of the air layer in the fuel tank according to the relative positional relationship between the liquid level of the fuel and the opening end, and the breather pipe In the opening end, a plurality of grooves are formed in the circumferential direction.

  According to the first aspect of the present invention, when the fuel level rises at the time of refueling and reaches the tip of the breather pipe, the refueling stops with the internal pressure of the fuel tank rapidly increasing. When the refueling is stopped, the air in the fuel tank expands by the difference from the atmospheric pressure and pushes the liquid level, the air in the air layer is released from the groove at the open end, and the pressure in the fuel tank is appropriately reduced.

  Since a plurality of grooves are formed in the opening end of the breather pipe in the circumferential direction, air from the air layer can be extracted by any of the grooves regardless of the inclination state of the vehicle (fuel tank). Further, even if the liquid level undulates depending on the oil supply speed, by forming the groove in consideration of the wave pitch, the trough portion of the liquid level can extract air corresponding to the groove. Further, by considering the balance between the oil supply speed and the air layer omission, the liquid level height at the time of initial oil supply can be reliably ensured.

  For this reason, regardless of the attitude of the vehicle, it is possible to suppress a sudden rise in the internal pressure of the fuel tank when the fuel level reaches the tip of the breather pipe, and to properly vent the air to ensure proper internal pressure. By reducing the fuel flow rate to a low value, it is possible to prevent external jetting of fuel that flows backward in the fuel supply pipe due to the increased fuel tank internal pressure during additional fueling.

  The number, height, and width of the grooves are appropriately set according to the area and capacity of the fuel tank in plan view, and the capability of the fuel supply device (fuel supply amount per unit time). In addition, by designing according to the vehicle, such as a design that emphasizes securing the liquid level height at the time of initial refueling, a design that emphasizes prevention of fuel injection at the time of additional refueling by suppressing a sudden increase in internal pressure, The number, height, and width of the grooves are set.

  The vehicle fuel tank structure of the present invention according to claim 2 is the vehicle fuel tank structure according to claim 1, wherein the opening end of the breather pipe is supplied to the fuel tank. The plurality of grooves are formed to have the same height from the end surface with respect to the liquid level of the fuel.

  In the present invention according to claim 2, since the open end of the breather pipe is an end face parallel to the liquid level of the fuel, and the plurality of grooves are formed at the same height with respect to the liquid level of the fuel, The air can be extracted under the same conditions regardless of the situation of the inclination in the axial direction and the inclination direction of the vehicle.

  A vehicle fuel tank structure according to a third aspect of the present invention is the vehicle fuel tank structure according to the second aspect, wherein the groove formed at the opening end of the breather pipe is the It is characterized by extending in an inclined manner with respect to the end face.

  A vehicle fuel tank structure according to a fourth aspect of the present invention is the vehicle fuel tank structure according to the second aspect, wherein the groove formed at the opening end of the breather pipe It is characterized by extending perpendicular to the end face.

  According to the structure of the fuel tank for a vehicle of the present invention, when the fuel level reaches the tip of the breather pipe, the internal pressure can be appropriately reduced by reliably venting air regardless of the position of the vehicle.

1 is an overall view of a vehicle provided with a fuel tank structure for a vehicle according to an embodiment of the present invention. It is a sectional side view showing the structure of a fuel tank. It is a side view of the tip of a breather pipe concerning one example. It is a front view of the tip of a breather pipe concerning one example. It is the VV arrow directional view in FIG. It is a graph showing the time-dependent change of the internal pressure of a fuel tank. It is a side view of the front-end | tip of the breather pipe which concerns on another Example.

  The overall structure of the vehicle fuel tank according to one embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 shows an overall situation of a vehicle having a fuel tank structure for a vehicle according to an embodiment of the present invention, and FIG. 2 shows a cross section of a fuel tank including a fuel supply pipe and a breather pipe.

  As shown in the figure, a fuel tank 2 is mounted on the lower side of the compartment of the vehicle 1. A fuel supply section 3 is provided on the rear side surface of the vehicle 1, and a filler neck section 5 of a fuel supply pipe 4 is disposed in the fuel supply section 3. The tip of the fuel supply pipe 4 is connected to the lower side of the fuel tank 2, and fuel is supplied to the fuel tank 2 through the fuel supply pipe 4 by inserting fuel supply means from the outside into the filler neck portion 5 and supplying fuel. Is supplied.

  A breather pipe 7 having a leading end is provided inside the fuel tank 2, and a base end of the breather pipe 7 is connected to the filler neck portion 5 and opens to the outside. The open end at the tip of the breather pipe 7 is an end surface parallel to the liquid surface 11F of the fuel 11 supplied to the fuel tank 2. When the liquid level 11F of the fuel 11 rises as the fuel is supplied and the pressure of the air layer 12 rises, the air in the air layer 12 is discharged from the breather pipe 7, and the pressure of the air layer 12 inside the fuel tank 2 is appropriate. Adjusted to

  When fuel is supplied into the fuel tank 2 through the fuel supply pipe 4, the liquid level 11 </ b> F of the fuel 11 rises and air in the air layer 12 inside the fuel tank 2 is discharged from the breather pipe 7. When the liquid level 11F of the fuel 11 rises and reaches the tip of the breather pipe 7, the opening end of the breather pipe 7 is blocked by the liquid level 11F of the fuel 11, and the air discharged to the outside is greatly reduced. As a result, the internal pressure of the fuel tank 2 suddenly increases, and at the same time, the air cannot be vented. In this state, it becomes impossible to put fuel into the tank, the liquid level in the oil supply pipe rises, and it is determined that the tank is full, and fuel supply is stopped.

  For this reason, based on the position of the front-end | tip part of the breather pipe 7, management of the liquid level 11F of the fuel 11, ie, management of the fuel amount supplied, can be performed.

  At the moment when refueling is stopped, the liquid level 11F of the fuel 11 is in a undulating state, and the tip of the breather pipe is blocked by the liquid level, making it impossible to put fuel into the tank. This is the situation before tank 2 is full, and when the waves stop over time, or when the valley of the waves reaches the tip of the breather pipe and is vented again through the breather pipe, additional fuel is supplied. can do. During refueling, the internal pressure of the fuel tank 2 is in a rapidly rising state, and the air in the air layer 12 in the fuel tank 2 expands by the difference from the atmospheric pressure due to the stop of refueling.

  For this reason, the fuel 11 is returned to the oil supply pipe by the internal pressure of the fuel tank 2, and the liquid level in the oil supply pipe rises again. When additional fuel is supplied immediately, the internal pressure of the fuel tank further increases, and the liquid level in the oil supply pipe further increases. At this time, there is a possibility that the amount of fuel additionally supplied will be ejected to the outside.

  In order to maintain the internal pressure of the fuel tank 2 at the time of refueling appropriately and to eliminate the ejection of fuel even if additional fuel is supplied, the details will be described later. A plurality of grooves are formed.

  The configuration of the tip of the breather pipe 7 will be specifically described with reference to FIGS.

  3 is a side view of the tip of a breather pipe according to an embodiment of the present invention, FIG. 4 is a front view of the breather pipe according to an embodiment of the present invention, and FIG. 5 is a breather pipe. The state of the VV line arrow in FIG. 3 showing the opening surface of the front-end | tip of is shown.

  As shown in FIG. 3, the center axis P of the tip 15 of the breather pipe 7 is inclined with respect to the liquid surface 11F of the fuel 11, and the end surface 15a of the open end is a surface parallel to the liquid surface 11F of the fuel 11. Has been.

  Since the end surface 15a of the open end is the end surface 15a of the intersecting surface inclined with respect to the central axis P of the tip 15 of the breather pipe 7, the area of the end surface 15a parallel to the liquid surface 11F of the fuel 11 is reduced. It can be made wider than the diameter, and the variation in the length of the tip 15 of the breather pipe 7 in the axial direction can be absorbed to maintain the liquid level height at the time of initial refueling in a predetermined state.

  As shown in FIGS. 3 to 5, a notch 16 is formed at one location around the end surface 15 a of the tip 15 of the breather pipe 7 (the tip side on the inclined obtuse angle side in the drawing). A plurality of (five in the illustrated example) grooves 21 are formed in a portion (in the periphery) excluding the notch 16 of the end face 15a of the tip 15 of the breather pipe 7. The groove 21 extends at an inclination angle along the central axis P of the tip 15 of the breather pipe 7 (inclined with respect to the end face 15a).

  In addition, in order to make it easy to remove the mold when the breather pipe 7 is formed, the shape is provided with the notch 16 at the tip 15 of the breather pipe 7, but the tip of the breather pipe 7 is not provided with the notch 16. It is also possible to form the groove 21 over the entire circumference of the 15 end faces 15a.

  Further, the example in which the central axis P of the tip 15 of the breather pipe 7 is inclined with respect to the liquid surface 11F of the fuel 11 has been described, but it extends perpendicularly to the liquid surface 11F of the fuel 11. It is also possible to make a breather pipe with a tip with a central axis. In this case, the space in the plane direction of the fuel tank occupied by the tip of the breather pipe 7 can be reduced, and the layout can be advantageous. By changing the arrangement height to the liquid surface 11F according to various fuel tanks. It becomes easy to apply to a plurality of fuel tanks.

  The plurality of grooves 21, including the notch 16, with respect to the liquid surface 11 </ b> F of the fuel 11, all have the same height h <b> 1 from the end surface 15 a. The groove 21 is set to a predetermined width w1.

  When the fuel 11 is supplied into the fuel tank 2 and the liquid level 11F of the fuel 11 rises and the liquid level 11F reaches the tip of the breather pipe 7, the opening end of the breather pipe 7 is at the liquid level 11F of the fuel 11. The internal pressure of the fuel tank rises at the same time as it becomes blocked by the air. In this state, fuel cannot be put into the tank, the liquid level in the oil supply pipe rises, and it is determined that the tank is full. At this time, the air layer 12 in the fuel tank 2 expands by a pressure difference from the atmospheric pressure, but air is discharged from the groove 21 (notch 16), and the rapid increase in internal pressure is suppressed at the same time after refueling. It is possible to appropriately reduce the fuel tank internal pressure.

  Since the plurality of grooves 21 are formed at the tip of the breather pipe 7, even if the liquid level 11 </ b> F undulates during refueling, a valley portion of the liquid level 11 </ b> F exists in any of the grooves 21, and the inside of the fuel tank 2 The air in the air layer 12 can be reliably discharged. Even when the vehicle is inclined, all the grooves 21 are not blocked by the liquid level 11F, so that the air in the air layer 12 in the fuel tank 2 can be reliably discharged.

  For this reason, the liquid level 11F of the fuel 11 is managed on the basis of the position of the tip of the breather pipe 7 by considering the balance between the flow rate of fueling and the discharge of air, and the internal pressure of the fuel tank 2 is rapidly increased. Therefore, it is possible to ensure the liquid level height at the time of initial oiling.

  Therefore, regardless of the position of the vehicle, when the liquid level 11F of the fuel 11 reaches the end surface 15a of the tip 15 of the breather pipe 7, it is possible to surely vent the air and appropriately reduce the internal pressure of the fuel tank 2. become.

  Thereby, even if the additional fuel 11 is supplied after the refueling is stopped, the internal pressure of the fuel tank 2 is maintained at an appropriate level, so that the fuel 11 is not returned and ejected outside.

  The number, height h1, and width w1 of the grooves 21 are appropriately set according to the area and capacity of the fuel tank 2 (see FIGS. 1 and 2) in plan view and the capability of the fuel supply device (the amount of fuel supplied per unit time). Is done.

  For example, the refueling flow rate supplied from the refueling gun is generally 30 to 40 L / min (0.5 to 0.67 L / sec), and depending on the fuel tank shape, the fuel tank has a capacity of about 40 L to 60 L When the liquid surface area of the liquid surface 11F near the full tank is 0.5 square meters, considering the wave wavelength of the liquid surface 11F during refueling, the height h1 of the groove 21 is about 2 mm at a minimum. Even if the liquid surface 11F undulates during refueling or the vehicle is inclined, the fuel tank 2 can be surely vented, and the internal pressure is not increased rapidly, and the tank is surely stabilized to a full tank state. Refueling becomes possible.

  The number, height h1, and width w1 of the grooves 21 are designed to emphasize the securing of the height of the liquid surface 11F at the time of initial refueling, and suppress a rapid increase in internal pressure of the fuel tank 2 (see FIGS. 1 and 2). At the same time, by appropriately reducing the internal pressure of the fuel tank after refueling, it can be appropriately set by a design that emphasizes the functions required of the vehicle, such as a design that emphasizes prevention of the ejection of the fuel 11 during additional refueling. it can.

  The state of the internal pressure of the fuel tank 2 during refueling will be described based on FIG.

  FIG. 6 shows a graph of change over time for explaining the state of the internal pressure of the fuel tank 2 during refueling.

  As shown by the solid line in FIG. 6, when refueling is started, the pressure in the fuel tank 2 increases until time t <b> 1 when air is discharged from the breather pipe 7. When air begins to be discharged from the breather pipe 7, the pressure in the fuel tank 2 is in an equilibrium state. When the liquid surface 11F of the fuel 11 reaches the end surface 15a of the breather pipe 7, the end surface 15a of the breather pipe 7 is blocked, the discharged air is reduced, and the pressure starts to increase (time t2).

  The speed at which the fuel enters the fuel tank 2 decreases and the pressure gradually increases. At time t3, fuel does not enter and fueling is stopped. That is, the internal pressure of the fuel tank 2 temporarily increases. After refueling stops (after the internal pressure has temporarily increased), the air in the fuel tank 2 is discharged from the groove 21 of the end face 15a of the breather pipe 7, and the internal pressure of the fuel tank 2 decreases (ΔP2: time t4). .

  Since the internal pressure of the fuel tank 2 is reduced, when additional fuel is supplied, the fuel in the fuel pipe is not returned by the internal pressure, and even if the liquid level in the pipe rises by the amount of additional fuel supplied , No fuel jets out.

  When the groove 21 is not formed in the end face 15a of the breather pipe 7, as shown by a dotted line in FIG. 6, when the fuel stops entering at the time t3 and the refueling is stopped, the internal pressure rapidly increases and the air Since there is no flow path through, the internal pressure does not drop sufficiently by time t4 (ΔP1: ΔP <ΔP2).

  That is, even if the internal pressure of the fuel tank 2 temporarily rises, the internal pressure of the fuel tank 2 can be lowered only to a state where the pressure is higher by ΔP than when the groove 21 is provided. For example, the pressure value decrease width ΔP2 when the groove 21 is provided can be set to be about 1.5 times the pressure value decrease width ΔP1 when the groove 21 is not formed.

  As described above, when the groove 21 is not formed, the internal pressure of the fuel tank 2 is maintained at a high level, and when the additional fuel is supplied, the fuel is returned by the internal pressure temporarily increased in the fuel tank 2. There is a risk that the fuel will be ejected to the outside.

  In the fuel tank structure described above, a plurality of grooves 21 are formed in the circumferential direction at the opening end of the breather pipe 7, so that the air in the air layer 12 is allowed to flow regardless of the inclination state of the vehicle 1 (fuel tank 2). By discharging from the groove 21, the internal pressure of the fuel tank 2 can be reduced.

  Further, even if the liquid surface 11F undulates due to the oil supply speed, the trough portion of the liquid surface 11F can discharge the air corresponding to the groove 21 by forming the groove 21 in consideration of the wave pitch. In addition, by considering the balance between the oil supply speed and the air discharge from the air layer 12, the height of the liquid surface 11F at the time of initial oil supply can be reliably ensured.

  For this reason, regardless of the attitude of the vehicle 1, when the liquid level 11 </ b> F of the fuel 11 reaches the tip 32 of the breather pipe 7, air is surely discharged from the groove 21 to appropriately reduce the internal pressure of the fuel tank 2. It becomes possible.

  Another embodiment of the breather pipe will be described with reference to FIG.

  FIG. 7 shows a side view of the tip of a breather pipe according to another embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the same member as the member shown in FIG.

  The breather pipe 31 shown in the drawing is arranged such that the central axis P of the tip 32 is inclined with respect to the liquid surface 11F of the fuel 11, and the end surface 32a of the open end is a surface parallel to the liquid surface 11F of the fuel 11. Yes.

  A notch 16 is formed at one location around the end surface 32a of the tip 32 of the breather pipe 31 (the tip side on the inclined obtuse angle side in the figure). A plurality of grooves 35 are formed in a portion (in the periphery) excluding the notch 16 of the end surface 15a of the tip 15 of the breather pipe 7. The groove 35 is formed to extend orthogonally (extend vertically) from the end surface 32a.

  The plurality of grooves 35 have the same height h <b> 2 from the end surface 32 a including the notch 16 with respect to the liquid level 11 </ b> F of the fuel 11. The groove 35 is set to a predetermined width w2.

  When the fuel 11 is supplied into the fuel tank 2 and the liquid level 11F of the fuel 11 rises and the liquid level 11F reaches the tip of the breather pipe 31, the air can not be vented and the internal pressure of the fuel tank rises. In this state, fuel cannot be put into the tank, the liquid level in the oil supply pipe rises, and it is determined that the tank is full. At this time, air in the air layer 12 in the fuel tank 2 is discharged from any of the plurality of grooves 35 regardless of the posture of the vehicle, and the rapid increase in internal pressure is reliably suppressed during refueling. It becomes possible to appropriately reduce the internal pressure of the tank 2.

  And since the groove | channel 35 is extended and formed orthogonally with respect to the liquid level 11F of the fuel 11, the depth of the groove | channel 35 becomes the height h2 as it is, and it can be set as the groove | channel 35 of sufficient height.

  INDUSTRIAL APPLICABILITY The present invention can be used in the industrial field of a fuel tank structure for a vehicle provided with a breather pipe that adjusts the pressure of an air layer in the fuel tank by performing air venting during refueling.

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Fuel tank 3 Refueling part 4 Fuel pipe 5 Filler neck part 7, 31 Breather pipe 11 Fuel 12 Air layer 15, 32 Tip 16 Notch 21, 35 Groove

Claims (4)

A fuel refueling pipe for supplying fuel into the fuel tank;
The fuel tank has an open end with an opening at the tip, and discharges air in the fuel tank, and the pressure of the air layer in the fuel tank is controlled by the relative positional relationship between the liquid level of the fuel and the open end. With a breather pipe to adjust,
A structure of a fuel tank for a vehicle, wherein a plurality of grooves are formed in a circumferential direction at the opening end of the breather pipe. In the structure of the fuel tank for vehicles according to claim 1,
The open end of the breather pipe is an end surface parallel to the liquid level of fuel supplied to the fuel tank,
The plurality of grooves are formed to have the same height from the end surface with respect to the liquid level of the fuel. In the structure of the fuel tank for vehicles according to claim 2,
The structure of the fuel tank for vehicles, wherein the groove formed at the opening end of the breather pipe extends in an inclined manner with respect to the end face. In the structure of the fuel tank for vehicles according to claim 2,
The structure of the fuel tank for vehicles, wherein the groove formed at the opening end of the breather pipe extends perpendicularly to the end face.

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