JP4847370B2 - Vehicle fuel tank - Google Patents

Description

  The present invention relates to a vehicular fuel tank, and more particularly, to a vehicular vehicular fuel tank in which a fuel chamber is divided into two parts by projecting a central portion of a bottom surface upward.

  Generally, in a front engine / rear drive type FR vehicle and a four-wheel drive (4WD) vehicle, a propeller shaft extends under the vehicle body. The propeller shaft is a rotating shaft that transmits the driving force of the engine mounted in front of the vehicle to the rear differential gearbox via the transmission, and is usually disposed at the vehicle body center in order to balance the drive system. Therefore, the fuel tank placed under the rear seat has a so-called saddle shape in which the center of the bottom of the tank protrudes upward so that it does not interfere with the propeller shaft, and the fuel chamber is divided into left and right parts. It is formed.

  In this type of vertical fuel tank, a filler pipe is connected to one of the left and right fuel chambers. Therefore, when liquid fuel is injected into the fuel tank, the fuel chamber to which the filler pipe is connected (hereinafter, The liquid fuel in which the liquid level of the main chamber) first rises and the bottom surface protrudes upwards and climbs over a projecting portion (hereinafter referred to as a bowl-shaped portion) is divided into the other fuel chamber (Hereinafter referred to as the sub chamber) to increase the liquid level of the sub chamber. After the liquid levels of the main chamber and the sub chamber reach the height of the bottom surface of the bowl-shaped part, the liquid level of the entire tank including the main chamber and the sub-chamber and the bowl-shaped part connecting them rises uniformly. Then the fuel tank becomes full.

  By the way, in general, a fuel tank for a vehicle is provided with a breather pipe that keeps the inside of the fuel tank at an atmospheric pressure during fuel injection to prevent spraying back. The breather pipe is installed so that one end is connected to the vicinity of the fuel inlet at the upper end of the filler pipe and the other end is connected to a breather joint that opens at a full tank liquid level in the fuel tank. . As a result, the injected liquid fuel or a gas corresponding to the volume of the air flowing into the fuel tank together with the liquid fuel is released to the atmosphere during the fuel injection, so that the liquid fuel is smoothly injected. Then, when the liquid level in the fuel tank reaches the lower end of the breather joint, that is, the full tank level during fuel injection, the pressure in the fuel tank rises due to the injected liquid fuel, and the liquid fuel in the fuel tank becomes the breather pipe. The fuel is discharged from the fuel inlet and the fuel supply gun detects this to activate the auto-stop function. In addition, since the breather joint is opened at a position lower than the upper end of the fuel tank by a predetermined height, even when liquid fuel is fully injected, an air layer is secured above the fuel tank and deformation of the fuel tank due to thermal expansion is prevented. ing.

  There is also a vehicular fuel tank provided with a fuel evaporative emission control device when refueling without the breather pipe. The fuel evaporative emission control device at the time of refueling temporarily stores the fuel evaporative gas in the fuel tank in the canister, thereby preventing the fuel evaporative gas being injected into the atmosphere from being released into the atmosphere. The canister has a built-in adsorbent such as activated carbon that adsorbs the fuel evaporative gas, and is connected to the fuel tank via a float valve by a large-diameter vent pipe. When the liquid level in the fuel tank does not reach the predetermined height, the fuel evaporative gas flows into the canister via the large-diameter vent pipe, and when the liquid level in the fuel tank reaches the predetermined height, the float valve The closing prevents liquid fuel from flowing into the large-diameter vent pipe.

  Such a liquid level detection means for detecting a liquid level height such as a breather joint and a float valve to perform a predetermined function is provided in the vicinity of the uppermost part in the fuel tank. Furthermore, it is desirable that the liquid level detection means is disposed at the vehicle body center, that is, at the center of the fuel tank. This is because the rear seats etc. are arranged above the fuel tank, so it is difficult to secure the upper space on both sides of the fuel tank, the gradient of the stop space of the gas station, the unbalanced load, etc. This is because the amount of fuel stored in the fuel tank can be kept constant even when the vehicle body is inclined. On the other hand, even if the liquid level detecting means is arranged at the center of the fuel tank, there is a limit to increasing the installation position of the liquid level detecting means. Therefore, in a vertical fuel tank provided with such a liquid level detection means at the top, depending on the tank shape, the injected liquid fuel passes from the main chamber through the vertical portion and flows into the sub chamber. However, there is a problem that the fuel gun auto-stop operates even though the fuel tank is not full, because the breather joint and the float valve are touched to operate them.

In order to solve this problem, liquid fuel flowing from the main chamber to the subchamber directly hits the float valve in a vertical vehicular fuel tank equipped with a float valve connected to a large-diameter vent pipe in the bowl-shaped portion. The present applicant has proposed a vehicular fuel tank configured to include a baffle plate for preventing the above.
JP 2004-189074 A

  However, in the vehicle fuel tank described in Patent Document 1, since a new member (baffle plate) has to be installed in the fuel tank, the manufacturing labor is increased. In addition to the breather joint and float valve, a fuel pump, a transfer pipe for transferring liquid fuel to the fuel pump, etc. are also arranged in the fuel tank, so the structure should be as simple as possible. desirable.

  The present invention has been made in view of such a background. The height of the bowl-shaped portion is kept low, and the malfunction of the liquid level detection means is avoided, so that the left and right fuel chambers of the vertical fuel tank can be smoothly smoothed. An object of the present invention is to provide a vehicular fuel tank having a simple configuration capable of injecting liquid fuel.

In order to solve the above-mentioned problems, the invention of claim 1 is characterized in that a first fuel chamber and a second fuel chamber divided into left and right by projecting the central portion of the bottom surface upward to form a hook-shaped portion. A vertical fuel tank main body having a fuel supply pipe connected to the first fuel chamber side, and a liquid fuel stored in the fuel tank main body. A vehicle fuel tank provided with a liquid level detector for detecting a liquid level, wherein a recess extending from the first fuel chamber to the second fuel chamber is formed on a bottom surface of the bowl-shaped portion. The liquid level detection means is formed at a position offset in the front-rear direction with respect to the depression .

According to a second aspect of the present invention, in the fuel tank for a vehicle according to the first aspect, the propeller shaft passes in the front-rear direction below the hook-shaped portion, and the recess is aligned with the small diameter portion of the propeller shaft. It arrange | positions in the position which carries out.

According to the first aspect of the present invention, the injected liquid fuel passes through the depression when flowing from the main chamber through the bowl-shaped portion and into the sub chamber, so that the liquid level detection means is positioned at a low position. Can be provided. This makes it possible to avoid the malfunction of the liquid level detection means while keeping the height of the bowl-shaped portion low, and to make the fuel for the vehicle with a simple configuration capable of smoothly injecting liquid fuel into the main chamber and the sub chamber. A tank is provided. Also, or injected liquid fuel that exceeds the allowable flow through the recess body, even if the liquid fuel overflowing from the depression by the vehicle body or inclined, the liquid fuel towards the recess in the main chamber Since the flow is generated, the liquid fuel that gets over the bowl-like portion passes around the depression and is prevented from coming into contact with the liquid level detection means. Further, according to the invention of claim 2 , the bottom surface of the bowl-shaped portion recessed downward is not interfered with the propeller shaft, and is suitable for carrying out the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, when explaining the direction of each member in drawing, the advancing direction of a motor vehicle is made into the front, and the left-right direction with respect to the advancing direction of a motor vehicle is made into the left direction and the right direction, respectively.

<< Configuration of Embodiment >>
FIG. 1 is a schematic view showing an automobile 1 equipped with a vehicle fuel tank 10 according to this embodiment. The automobile 1 is a four-wheel drive vehicle having an engine 2 mounted on the front side, and a propeller shaft 3 extends in the front-rear direction at the lower part of the vehicle body. The propeller shaft 3 connects a transmission 4 connected to the engine 2 and a rear differential gear box 5 that rotationally drives the rear wheel, and transmits the driving force of the engine 2 to the rear wheel. The automobile 1 is provided with a front seat 6 and a rear seat 7, and a vehicle fuel tank 10 is disposed below the rear seat 7 so as to straddle the propeller shaft 3.

  FIG. 2 is a cross-sectional view of the vehicular fuel tank 10 according to the present embodiment, and represents a view taken along the line II-II in FIG. A fuel tank 11 (fuel tank main body) constituting the vehicle fuel tank 10 has a cross section from a tank bottom surface 12, a tank top surface 13, a tank right side surface 14 (left side in the drawing), and a tank left side surface 15 (right side in the drawing). The fuel chamber 21 is demarcated inside. The central portion 12a of the tank bottom surface 12 protrudes upward over the entire length in the front-rear direction of the fuel tank 11, forms a flange-shaped portion 22, and divides the fuel chamber 21 into left and right main chambers 23 (first chambers). The fuel chamber) and the sub chamber 24 (second fuel chamber) are formed. Further, the central portion 13 a of the tank upper surface 13 also protrudes upward along the central portion 12 a of the tank bottom surface 12. Here, regardless of the installation position of the fuel pump (not shown), the fuel chamber into which liquid fuel is first injected is referred to as a main chamber 23, and the other divided fuel chamber is referred to as a sub chamber 24. A portion connecting the main chamber 23 and the sub chamber 24 at the upper portion is referred to as a bowl-shaped portion 22.

  A fuel injection filler pipe 31 (fuel supply pipe) inserted through the upper surface 13 is connected to the main chamber 23. A first check valve 32 is connected to the lower end of the filler pipe 31, and a breather pipe 34 extending from the upper part of the fuel tank 11 is connected to the fuel inlet 33 at the upper end of the filler pipe 31. It is connected via a stop valve 35.

  The fuel tank 11 is provided with a fuel evaporative gas discharge prevention device 41 for refueling in order to prevent the evaporated gas in the fuel tank 11 from being released to the atmosphere. The fuel evaporative emission prevention device 41 at the time of refueling includes a float valve 42 (liquid level height detecting means) suspended from the central portion 13 a of the tank upper surface 13, a canister 43 containing activated carbon inside, a float valve 42 and a canister 43. It is comprised from the vent pipe 44 etc. which connect. The canister 43 is connected to an intake manifold of an engine (not shown) through a solenoid valve 46 for purge control, and is open to the atmosphere through a canister filter 47.

  The propeller shaft 3 passes in the front-rear direction below the flange-shaped portion 22 of the fuel tank 11, and the central portion 12 a of the tank bottom surface 12 is shaped so as not to interfere with the propeller shaft 3.

  FIG. 3 is a longitudinal sectional view of the vehicular fuel tank 10 according to this embodiment, and represents a view taken along arrows III-III in FIG. As shown in FIGS. 2 and 3, the fuel tank 11 is installed such that a central portion 12 a protruding above the tank bottom surface 12 is substantially horizontal, and the central portion 12 a of the tank bottom surface 12 is a flat bowl. The bottom surface of the shape portion 22 is formed. A recess 12 b extending from the main chamber 23 to the sub chamber 24 is formed in a part of the bottom surface of the bowl-shaped portion 22. The recess 12b is formed rearward (right side of the drawing) from the center of the fuel tank 11.

  The cross section of the propeller shaft 3 that passes below the bowl-shaped portion 22 has a hollow pipe shape as shown in FIG. 2 in the intermediate portion 3a, and is near the joint portion 3b (small diameter portion) that is connected to the rear differential gearbox 5. In it has a solid circular shape. Therefore, the diameter of the vicinity of the joint portion 3b is reduced while ensuring the same rigidity as the intermediate portion 3a. The recess 12 b formed on the bottom surface of the bowl-shaped portion 22 is disposed at a position aligned with the joint portion 3 b of the propeller shaft 3.

  On the other hand, the float valve 42 is formed slightly forward (left side in the drawing) from the center of the fuel tank 11. Since there is a spatial restriction above the fuel tank 11, the full tank liquid level is close to the bottom surface of the bowl-shaped portion 22, and the liquid level of the main chamber 23 and the sub chamber 24 is finally connected near the full tank. Is set.

<< Effects of Embodiment >>
Next, functions and effects of the embodiment will be described. First, the general operation of the fuel tank 11 will be described with reference to FIGS. When the filler cap 36 is removed and the fuel gun 39 is inserted into the fuel injection port 33 to inject liquid fuel, the injected liquid fuel is first stored in the main chamber 23 through the filler pipe 31. When the liquid level in the main chamber 23 becomes higher than the central portion 12 a of the tank bottom surface 12, the liquid fuel flows into the sub chamber 24 through the bowl-shaped portion 22. When the fuel tank 11 becomes full after the sub chamber 24 is filled, the fuel supply fuel is not supplied to the tank any more due to the closure of the float valve 42, and the liquid level rises toward the filler gun 39 through the filler pipe 31. . In the fueling gun 39, a sensor provided at the tip of the nozzle detects this and activates the auto-stop function.

  When the liquid level in the fuel tank 11 is equal to or lower than a predetermined height (the height at which the float type valve element 42a accommodated in the float valve 42 floats and the float valve 42 closes), the float valve 42 The evaporated gas in the tank 11 is circulated through the vent pipe 44. On the other hand, when the liquid level in the fuel tank 11 reaches a predetermined height, the float valve 42 is closed to prevent liquid fuel from entering the vent pipe 44. When the float valve 42 is in the open state, the evaporated gas that has flowed into and stored in the canister 43 is controlled by a non-illustrated electronic control unit (ECU) during operation of the engine 2 so that the negative pressure of the intake manifold is reduced. The pressure is discharged to the intake manifold together with the outside air sucked through the canister filter 47.

  Further, when the fuel tank 11 is cooled by the influence of outside air or the like and the air in the tank contracts, the evaporated gas temporarily stored in the canister 41 is returned to the fuel tank 11. If ventilation from the canister cannot be obtained due to problems such as blockage of the pipeline, the negative pressure valve of the filler cap 36 is opened to introduce outside air, thereby preventing the fuel tank 11 from being deformed.

  Next, the function and effect of the present invention will be described with reference to FIGS. FIG. 4 is an operation explanatory view showing the flow of the liquid fuel 50 in the vehicle fuel tank 10 according to the present embodiment. As shown in FIG. 3, the recess 12 b formed on the bottom surface of the bowl-shaped portion 22 is formed so as to reach the sub-chamber 24 from the main chamber 23 while forming a surface lower than the bottom surface of the other bowl-shaped portion 22. ing. Therefore, the recess 12 b functions as a flow path for the liquid fuel 50 flowing from the main chamber 23 into the sub chamber 24. Thereby, when the liquid level of the liquid fuel 50 injected into the main chamber 23 from the fuel gun 39 becomes higher than the depression 12b, the liquid fuel 50 forms a flow toward the depression 12b and passes through the depression 12b. Pass through. Therefore, the liquid fuel 50 flowing into the sub chamber 24 from the main chamber 23 does not pass through the bowl-shaped portion 22 other than the recess 12b and does not contact the lower end of the float valve 42. Therefore, the float valve 42 is prevented from operating before the fuel tank 11 is full, while the height of the flange 22 is kept low.

  Even if the liquid fuel 50 that passes through the bowl-shaped portion 22 exceeds the allowable amount flowing through the depression 12b, the flow of the liquid fuel 50 toward the depression 12b is formed in the main chamber 23. It will pass through the bowl-shaped part 22, and it is suppressed that it contacts the float valve 42 arrange | positioned in the front direction offset from the installation position of the hollow 12b.

  Further, the fuel tank 11 exhibits the above-described effects in a simple configuration in which the recess 12b is formed in the central portion 12a of the tank bottom surface 12, and in the same process (work effort) as the manufacturing process of a normal vertical fuel tank. A vertical vehicular fuel tank 10 is obtained, and an increase in the number of parts is also avoided.

<< Modified Embodiment >>
Next, a modified embodiment will be described with reference to FIG. FIG. 5 shows a cross-sectional view of a vehicle fuel tank 60 according to a modified embodiment. In the description, the description of the same configuration and operation as those of the above-described embodiment is omitted, and different points from the above-described embodiment. Explain mainly. The fuel tank 61 has the same shape as that of the above embodiment, but is not provided with a fuel evaporative gas discharge prevention device during refueling, and a breather in which a breather pipe 84 is connected to a central portion 63a of the tank upper surface 63. A joint 87 (liquid level height detecting means) is suspended. An opening 87 a is formed at the lower end of the breather joint 87. Since the central portion 63a of the tank upper surface 63 cannot be protruded largely upward due to the balance with the peripheral facilities, the full tank liquid level is close to the bottom surface of the bowl-shaped portion 22, and finally the main chamber 23 and the sub chamber 24 The liquid level is set to be connected.

  When the liquid fuel injected from the fuel gun 39 into the main chamber 73 comes into contact with the opening 87a of the breather joint 87, it detects that the liquid fuel has reached the full tank level and performs its function. That is, the liquid level rise of the liquid fuel is stopped at the full tank level, and the liquid fuel in the fuel tank 61 is circulated through the breather pipe 84 and discharged to the fuel injection port 33 using the pressure of the injected liquid fuel. To do. Similarly to the above embodiment, the recess 62b extending from the main chamber 73 to the sub chamber 74 is formed on the bottom surface of the bowl-shaped portion 72, so that the liquid fuel flowing from the main chamber 73 into the sub chamber 74 The lower end is not contacted and the function of the breather joint 87 before the fuel tank 61 becomes full is avoided. Accordingly, liquid fuel is smoothly injected into the main chamber 73 and the sub chamber 74 without causing the pressure in the fuel tank 61 to rise and causing blowback or the automatic stop function of the fuel gun 39 to be activated early. It is possible.

  This is the end of the description of specific embodiments, but the present invention is not limited to these embodiments. For example, in the above-described embodiment, the vehicle fuel tank is applied to a four-wheel drive vehicle in front of the engine. However, the present invention can naturally be applied to FR vehicles, rear engine vehicles, trains, and the like. Further, only the fuel evaporative gas emission preventing device at the time of refueling may be provided, and the breather pipe connected to the fuel supply port may not be provided. Furthermore, the fuel tank may be mounted on the vehicle so that the hook-shaped portion extends in a direction perpendicular to the traveling direction as well as the hook-shaped portion extends in the traveling direction of the vehicle. Further, the liquid level detection means is not limited to the float valve and the breather joint, but any other member that detects the liquid level of the liquid fuel stored in the fuel tank body. Also good. In addition to such changes, changes can be made as appropriate without departing from the spirit of the present invention.

Schematic showing a vehicle equipped with a fuel tank according to an embodiment 1 is a cross-sectional view of a fuel tank for a vehicle according to an embodiment (viewed along arrow II-II in FIG. 1). FIG. 2 is a longitudinal sectional view of the fuel tank for a vehicle according to the embodiment (a view taken along arrows III-III in FIG. 2). Action explanatory drawing of the fuel tank for vehicles concerning an embodiment Cross-sectional view of a vehicle fuel tank according to a modified embodiment

Explanation of symbols

3 Propeller shaft 3b Joint part (small diameter part)
10, 60 Vehicle fuel tank 11, 61 Fuel tank (fuel tank body)
12, 62 Tank bottom surface 12a, 62a Center portion 12b, 62b Depression 22, 72 Hook-like portion 23, 73 Main chamber (first fuel chamber)
24, 74 Sub chamber (second fuel chamber)
31, 81 Filler pipe (fuel supply pipe)
42 Float valve (liquid level detection means)
87 Breather joint (liquid level detection means)
50 Liquid fuel

Claims (2)

A first fuel chamber and a second fuel chamber, which are divided into left and right parts, are defined inside by projecting a central part of the bottom surface upward to form a flange-like part, and a fuel is provided on the first fuel chamber side. A vertical fuel tank body to which a supply pipe is connected;
A vehicular fuel tank provided with an upper surface of the bowl-like portion and provided with a liquid level detecting means for detecting a liquid level of liquid fuel stored in the fuel tank body;
Forming a recess from the first fuel chamber to the second fuel chamber on the bottom surface of the bowl-shaped portion ;
The vehicle fuel tank according to claim 1, wherein the liquid level detection means is provided at a position offset in the front-rear direction with respect to the recess . A propeller shaft passes under the hook-like portion in the front-rear direction,
The vehicle fuel tank according to claim 1, wherein the recess is disposed at a position aligned with a small diameter portion of the propeller shaft.

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