Vapor separator tank

Abstract

To provide a vapor separator tank in which the capacity of a fuel storage chamber is sufficiently secured, and other equipment and components can be easily arranged in the periphery while facilitating the design change.SOLUTION: In a VST (vapor separate tank) 10, a lower case 22 is provided with a plurality of mounting parts 28 mounted to an engine (internal combustion) 3, and a drain pipe 22a for discharging liquid fuel from a fuel tank 26. The lower case 22 includes a first bottom surface portion 61 including a lowermost surface, a second bottom surface portion 62 provided above the first bottom surface portion 61 and supporting the pump 40, and a third bottom surface portion 63 provided above the first bottom surface portion 61 and the second bottom surface portion 62.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a vapor separator tank. [Background technology]

[0002] Conventionally, there has been known a technique relating to a vapor separator tank that separates gas from liquid fuel supplied to an internal combustion engine. For example, Patent Document 1 describes a vapor separator tank in which a fuel storage chamber is formed inside a casing composed of a lower case that forms a fuel storage chamber and an upper case that closes an upper opening of the lower case. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-73630 Summary of the Invention [Problem to be solved by the invention]

[0004] Since vapor separator tanks are generally located close to the internal combustion engine, multiple pipes and parts of related equipment are often located around them. Furthermore, the vapor separator tank is provided with drain pipes and attachment parts to the internal combustion engine. Therefore, it is preferable to secure as much space as possible for these. At the same time, it is also necessary to secure the capacity of the vapor separator tank, and it is preferable to enable easy design changes to the capacity.

[0005] The present invention was made in consideration of these problems, and its purpose is to provide a vapor separator tank that ensures sufficient capacity for the fuel storage chamber, facilitates design changes, and makes it easy to arrange other equipment, parts, or its own components around it. [Means for solving the problem]

[0006] In order to achieve the above object, the vapor separator tank of the present invention is a vapor separator tank that is mounted on an outboard motor and separates gas from liquid fuel supplied to an internal combustion engine, and is equipped with a casing having a lower case and an upper case joined together and having a fuel storage chamber formed therein for storing the liquid fuel, a pump that pressurizes the liquid fuel stored in the fuel storage chamber, and a pressure regulator that is disposed in the fuel storage chamber and adjusts the discharge pressure of the pump to a constant level, the lower case is provided with a plurality of mounting portions that are attached to the internal combustion engine and a drain pipe for discharging the liquid fuel from the fuel storage chamber, and the lower case includes a first bottom surface portion that includes the lowest surface, a second bottom surface portion that is formed above the first bottom surface portion and that supports the pump, and a third bottom surface portion that is formed above the first and second bottom surfaces.

[0007] The drain pipe may be provided below the second bottom surface portion.

[0008] The third bottom surface portion may be located forward of the outboard motor with respect to a first center line of the lower case and at a corner portion on either the left or right side of the outboard motor with respect to a second center line of the lower case that is perpendicular to the first center line.

[0009] The third bottom surface portion may be located below the pressure regulator and to the side of the pump.

[0010] The third bottom surface portion may be located above an intake port of the pump. [Effects of the Invention]

[0011] According to the vapor separator tank of the present invention, it is possible to obtain a configuration that allows other devices, parts, or the tank's own components to be easily arranged around the tank, while ensuring the capacity of the fuel storage chamber and the ease of modifying its design. [Brief explanation of the drawings]

[0012] [Figure 1]1 is a side view schematically showing an outboard motor equipped with a vapor separator tank according to an embodiment. [Figure 2] FIG. 2 is a plan view schematically showing the outboard motor. [Figure 3] FIG. 2 is a perspective view of the vapor separator tank as viewed obliquely from above. [Figure 4] FIG. 2 is a perspective view of the vapor separator tank as viewed obliquely from below. [Figure 5] FIG. [Figure 6] FIG. 6 is a cross-sectional view of the vapor separator tank taken along line AA in FIG. 5. [Figure 7] 6 is a cross-sectional view of the vapor separator tank taken along the second center line of FIG. 5. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0014] FIG. 1 is a side view schematically showing an outboard motor equipped with a vapor separator tank according to an embodiment. FIG. 2 is a plan view schematically showing the outboard motor. Below, each component will be described based on the longitudinal, transverse, and vertical directions of a boat (not shown) on which the outboard motor 1 is mounted. The outboard motor 1 is mounted on a boat and rotates a propeller 4 using power from a multi-cylinder engine (internal combustion engine) 3 mounted in a main body case 2. As shown in FIG. 2, within the main body case 2, an intake manifold 5 for drawing air into the engine 3 includes multiple intake pipes 5a arranged to extend longitudinally from a mixing body at intervals from the side of the engine 3. Note that the multiple intake pipes 5a are not shown in FIG. 1.

[0015] The outboard motor 1 is equipped with a vapor separator tank 10 (hereinafter referred to as "VST 10") that temporarily stores liquid fuel to be supplied to the engine 3 and has a gas-liquid separation function that separates gases such as evaporated gas and air bubbles from the liquid fuel. The VST 10 is connected between the engine 3 and a fuel tank (not shown) that stores liquid fuel, and liquid fuel is supplied from the fuel tank by a low-pressure pump (not shown). In this embodiment, the VST 10 is attached to the front of the engine 3. However, the VST 10 may also be disposed in the space between the side of the engine 3 and the intake manifold 5.

[0016] The specific configuration of the VST 10 will be described below with reference to Figs. 3 to 7. Fig. 3 is a perspective view of the VST 10 viewed obliquely from above. Fig. 4 is a perspective view of the VST 10 viewed obliquely from below. Fig. 5 is a bottom view of the VST 10. Fig. 6 is a cross-sectional view of the VST 10 taken along line AA in Fig. 5. Fig. 7 is a cross-sectional view of the VST 10 taken along the second center line L2 in Fig. 5. As shown in Figs. 6 and 7, the VST 10 includes a casing 20, a float mechanism 30, a pump 40, and a pressure regulator 50.

[0017] The casing 20 has a lower case 22 and an upper case 24. The lower case 22 defines a fuel storage chamber 26 that stores liquid fuel. The fuel storage chamber 26 is a space surrounded by a bottom surface 60 of the lower case 22 and a side wall 70 extending upward from the bottom surface 60. A drain pipe 22a is formed in the lower part of the lower case 22 for discharging fuel during maintenance or when the internal combustion engine is not used for an extended period of time during the off-season. The lower case 22 also defines multiple mounting portions 28 for mounting the VST 10 to the engine 3. The mounting portions 28 are located on the upper right, upper left, lower right, and lower left sides of the lower case 22, with a total of four mounting portions 28 extending from the outer surface. Hereinafter, the mounting portion 28 on the lower left side will be referred to as the "mounting portion 281."

[0018] The upper case 24 is a lid-like member that closes the upper opening of the lower case 22, and is joined to the lower case 22 using fasteners. The upper case 24 is provided with a fuel inlet 24a through which liquid fuel flows in from the fuel tank, and a fuel outlet 24b through which liquid fuel supplied to the engine 3 flows out. The fuel outlet 24b is connected to the discharge port of a pump 40, which will be described later. The upper case 24 also has two air vents 24d that discharge gases, such as evaporated fuel and air bubbles from the liquid fuel, to the outside.

[0019] The float mechanism 30 has a float 32, a connecting member 34, and a float valve 36. The float 32 is supported so as to be able to swing freely on the upper case 24 via the connecting member 34, a portion of which is shown in Figure 6, and floats on the liquid fuel in the fuel storage chamber 26. The float 32 moves in accordance with the up and down movement of the liquid fuel level LS, which is illustrated by the dashed line in Figure 6. The connecting member 34 is structured so as to move up and down simultaneously with the float valve 36, which is provided in a flow path communicating with the fuel inlet portion 24a.

[0020] As a result, when the amount of liquid fuel in the fuel storage chamber 26 is less than a predetermined reference value, the float 32 is positioned below a predetermined position, causing a portion of the connecting member 34 to push down on the valve element of the float valve 36, thereby opening the float valve 36. As a result, liquid fuel flows into the fuel storage chamber 26 from the fuel inlet 24a. On the other hand, when the amount of liquid fuel in the fuel storage chamber 26 is equal to or greater than the reference value, the float 32 attempts to position above the predetermined position, causing a portion of the connecting member 34 to push up on the valve element of the float valve 36, thereby closing the float valve 36. As a result, the flow of liquid fuel from the fuel inlet 24a into the fuel storage chamber 26 is restricted. Therefore, the amount of liquid fuel in the fuel storage chamber 26 is kept constant.

[0021] As shown in FIG. 7, pump 40 is a high-pressure pump that is mounted within casing 20 and pressure-feeds liquid fuel stored in fuel storage chamber 26. Pump 40 is a vertical pump disposed within pump housing 262 (described later) and has an intake port 42 at its bottom and an outlet port at its top. A filter 80 (FIG. 6) that filters the liquid fuel in fuel storage chamber 26 is connected to intake port 42 of pump 40. Meanwhile, the outlet port of pump 40 is connected via discharge pipe 44 to fuel outlet 24b formed in upper case 24. Liquid fuel discharged from pump 40 is guided via discharge pipe 44 to fuel outlet 24b and pressure-feeds to engine 3. A pressure regulator 50 is connected to a midpoint of discharge pipe 44 via relief pipe 46 that extends horizontally from discharge pipe 44.

[0022] The pressure regulator 50 is configured to include a valve body, a valve seat, a spring, and other components (not shown) in a substantially cylindrical case, and opens in response to an increase in the pressure of the fuel flowing into the relief pipe 46, allowing excess fuel to return to the fuel storage chamber 26. This adjusts the discharge pressure of the pump 40, i.e., the pressure of the liquid fuel supplied to the engine 3, to a constant value.

[0023] Next, the detailed shape of the VST 10 will be described. In the following description, one of the center lines of the casing 20 (lower case 22) extending in the horizontal direction shown in FIG. 5 will be referred to as the "first center line L1," and the other will be referred to as the "second center line L2." Furthermore, the direction along the first center line L1 will be referred to as the "first direction X," and the direction along the second center line L2 will be referred to as the "second direction Y." In this embodiment, the first direction X is the longitudinal direction of the casing 20 (lower case 22) and the left-right direction of the outboard motor 1, and the second direction Y is the lateral direction of the casing 20 (lower case 22) and the fore-aft direction of the outboard motor 1. Note that the relationships between the first direction X and the second direction Y and the longitudinal direction, the lateral direction, the left-right direction, and the fore-aft direction are not limited to those described above.

[0024] The lower case 22 has a bottom surface portion 60 including a first bottom surface portion 61, a second bottom surface portion 62, and a third bottom surface portion 63, and a side wall portion 70 including a first side wall portion 71, a second side wall portion 72, and a third side wall portion 73 extending upward from the bottom surface portion 60. The first bottom surface portion 61 is the bottom surface portion that includes the lowest surface of the entire VST 10. As shown in FIG. 5, the first bottom surface portion 61 is formed to have a size that is approximately half the size of the fuel storage chamber 26 in the first direction X. As shown in FIGS. 3 and 6, a first side wall portion 71 extends from the first bottom surface portion 61. The first bottom surface portion 61, together with the first side wall portion 71, forms a main storage portion 261, which is the main space of the fuel storage chamber 26. In other words, the first bottom surface portion 61 forms the main bottom surface portion of the fuel storage chamber 26.

[0025] As shown in Fig. 5, the second bottom surface portion 62 is formed at a position slightly offset from the first bottom surface portion 61 in the first direction X, and has a size that is approximately half the size of the fuel storage chamber 26. As shown in Figs. 3 and 7, a second side wall portion 72 extends from the second bottom surface portion 62. The second bottom surface portion 62, together with the second side wall portion 72, forms a pump accommodating portion 262 of the fuel storage chamber 26 in which the pump 40 is accommodated, and supports the pump 40. The second bottom surface portion 62 is formed higher than the first bottom surface portion 61.

[0026] As shown in Fig. 5, the third bottom surface portion 63 is formed at a corner portion 25 of the lower case 22. When the VST 10 is viewed from above and below, the corner portion 25 is located at any of four regions defined by the first center line L1 and the second center line L2, and is a range extending from the side wall portion 70 (third side wall portion 73) of the portion of the lower case 22 that constitutes the fuel storage chamber 26 toward the center 221. More specifically, as shown in Fig. 5, the third bottom surface portion 63 is formed at a position offset from the first bottom surface portion 61 in the first direction X and at a position offset from the second bottom surface portion 62 in the second direction Y. In other words, the center of the third bottom surface portion 63 is disposed at a position offset from both the first center line L1 and the second center line L2. 5, the third bottom surface portion 63 is not limited to a portion that does not entirely overlap the first center line L1 and the second center line L2, and the vicinity of the end portion may be formed beyond the first center line L1 and the second center line L2. The size of the third bottom surface portion 63 is approximately one-fourth of the size of the fuel storage chamber 26.

[0027] In this embodiment, as shown in FIG. 7 , the third bottom surface portion 63 is provided on a side of the pump 40 different from the side on which the suction port 42 is formed. The third bottom surface portion 63 extends horizontally below the pressure regulator 50. This allows the third bottom surface portion 63 to receive the liquid fuel from the pressure regulator 50 when the third bottom surface portion 63 is positioned above the liquid level LS. As a result, the liquid fuel is prevented from dripping onto the liquid level LS, thereby suppressing the generation of bubbles in the liquid fuel and preventing the liquid fuel containing bubbles from being sucked into the pump 40. Therefore, it is more preferable that the third bottom surface portion 63 be provided near the pressure regulator 50 and above the height of the liquid level LS that is aimed to be maintained by the float mechanism 30. The third bottom surface portion 63 is positioned above the first bottom surface portion 61 and the second bottom surface portion 62. As shown in Figures 6 and 7, a third side wall portion 73 extends from the third bottom surface portion 63, and the third bottom surface portion 63 and the third side wall portion 73 form a secondary storage portion 263 that is part of the fuel storage chamber 26.

[0028] 3 and 4, a first space 91 is formed around the VST 10 below the second bottom surface portion 62. As a result, the first space 91 can be used to extend the drain pipe 22a from the first side wall portion 71 in the horizontal direction, more specifically in the left-right direction of the outboard motor 1. This allows the VST 10 to be made more compact than if the drain pipe 22a were to extend downward from the first bottom surface portion 61 or in the front-rear direction from the first side wall portion 71.

[0029] Additionally, second spaces 92 are formed around the VST 10 below the third bottom surface portion 63 at positions corresponding to the corners 25. In this way, by utilizing portions of the corners 25, where excess space is likely to be generated within the fuel storage chamber 26, as the second spaces 92, it becomes easier to arrange other devices and components, such as piping (not shown) and components of the intake manifold 5 of the outboard motor 1. Alternatively, it becomes possible to reduce the size of the main body case 2 of the outboard motor 1 by the amount of the second spaces 92. The VST 10 of this embodiment is sometimes disposed in front of the engine 3, which tends to impose restrictions on the horizontal length, more specifically, the length in the lateral direction of the outboard motor 1, and therefore has an overall nearly square shape. Even with this shape, the second spaces 92 facilitate the arrangement of other devices and components. At the same time, the capacity can be secured in other areas of the fuel storage chamber 26, excluding the corners 25, thereby preventing a decrease in the overall capacity of the VST 10.

[0030] Furthermore, by forming the second space 92 in the corner portion 25, the second space 92 can be used to increase the degree of freedom in arranging the mounting portion 281, which extends horizontally, more specifically, in the left-right direction of the outboard motor 1. The mounting portion 281 is provided near the pump 40, which is heavy and prone to vibration, and is therefore susceptible to the effects of vibration. With the configuration of this embodiment, the mounting portion 281 can be provided at a desired position within the second space 92 while taking into account the effects of vibration.

[0031] Furthermore, in this embodiment, the third bottom surface portion 63 is formed at least above the upper end position of the intake port 42 of the pump 40 (the position indicated by the dashed-dotted line in FIG. 7). As a result, the auxiliary reservoir 263 is located above the intake port 42. Because it is difficult for liquid fuel to be drawn into the fuel reservoir chamber 26 from below the intake port 42, it is preferable to increase the range above the intake port 42 in order to increase the capacity of the fuel reservoir chamber 26. In this embodiment, since the auxiliary reservoir 263 is located above the intake port 42, it can be said that the capacity of the fuel reservoir chamber 26 can be more effectively ensured.

[0032] Additionally, the capacity of the fuel storage chamber 26 can be adjusted by adjusting the height of the third bottom surface portion 63. The capacity of the fuel storage chamber 26 may be changed from the initial design value depending on other design factors, such as the components and part shapes, when installing the VST 10 on the outboard motor 1. Furthermore, it is not easy to change the capacity of the fuel storage chamber 26 alone after the specifications of the VST 10, including the other design factors, have been determined. That is, as described above, it is not desirable to increase the size of the fuel storage chamber 26 downward from the intake port 42 of the pump 40. Furthermore, increasing the upper opening of the lower case 22 requires a major design change, which increases the number of steps required for the design change. In this embodiment, the capacity of the fuel storage chamber 26 can be adjusted simply by adjusting the height of the third bottom surface portion 63, which is located in the corner portion 25, which can be easily utilized as surplus space. This makes it easier to change the design of the capacity of the fuel storage chamber 26 even after other specifications of the VST 10 have been determined. Furthermore, since capacity changes can be accommodated by changing only a portion of the mold used to manufacture the lower case 22, it is preferable to prepare in advance a mold whose portion for forming the third bottom surface portion 63 can be replaced.

[0033] As described above, in the VST (vapor separator tank) 10 of the embodiment, the lower case 22 is provided with a plurality of mounting portions 28 that extend from the outer surface and are attached to the engine (internal combustion engine) 3, and a drain pipe 22a for discharging liquid fuel from the fuel storage chamber 26. The lower case 22 includes a first bottom surface portion 61 that includes the lowest surface, a second bottom surface portion 62 that is formed above the first bottom surface portion 61 and supports the pump 40, and a third bottom surface portion 63 that is formed above the first bottom surface portion 61 and the second bottom surface portion 62.

[0034] With this configuration, as described above, it is possible to use first space 91 below second bottom surface portion 62 and second space 92 below third bottom surface portion 63 to place other devices or parts, or its own components such as drain pipe 22a and mounting portion 281. Furthermore, by adjusting the height of third bottom surface portion 63, it is possible to ensure the capacity of fuel storage chamber 26 and ease of design changes thereto.

[0035] Furthermore, the drain pipe 22a is provided below the second bottom surface portion 62. With this configuration, the drain pipe 22a can be disposed within the first space 91, thereby enabling the VST 10 to be made smaller in size.

[0036] Furthermore, the third bottom surface portion 63 is disposed forward of the outboard motor 1 relative to the first center line L1 of the lower case 22, and at a left corner 25 of the outboard motor 1 relative to a second center line L2 of the lower case 22 that is perpendicular to the first center line L1. This configuration makes it possible to arrange other devices, parts, and mounting portions 281 in the second space 92 at the front of the outboard motor 1, and to reduce the size of the outboard motor 1 by the amount of the second space 92. It also increases the degree of freedom in arranging the mounting portion 281. The third bottom surface portion 63 may also be disposed at a right corner of the outboard motor 1 relative to the second center line L2.

[0037] Moreover, the third bottom surface portion 63 is disposed below the pressure regulator 50 and to the side of the pump 40. With this configuration, the liquid fuel from the pressure regulator 50 can be more easily received by the third bottom surface portion 63, making it possible to prevent air bubbles from being generated in the liquid fuel. Furthermore, by providing the second space 92 to the side of the pump 40, the mounting portion 281 can be provided at a position that takes into consideration vibration of the pump 40.

[0038] Additionally, third bottom surface portion 63 is located above intake port 42 of pump 40. With this configuration, the capacity of fuel storage chamber 26 can be secured by the capacity of sub storage portion 263.

[0039] In the present embodiment, the third bottom surface portion 63 extends horizontally. However, as illustrated by the dashed line in FIG. 6 , the third bottom surface portion 63 may extend obliquely downward from the pressure regulator 50 side toward the center of the fuel storage chamber 26. This can more effectively prevent air bubbles from being generated in the liquid fuel from the pressure regulator 50. Furthermore, by adjusting the inclination angle of the third bottom surface portion 63, it is possible to straighten the liquid fuel from the pressure regulator 50 containing air bubbles so as to prevent it from flowing toward the intake port 42 of the pump 40.

[0040] 6 and 7, a standing wall portion 65 extending upward from the third bottom surface portion 63 may be provided. The standing wall portion 65 is provided at a position that prevents the liquid fuel from the pressure regulator 50 from flowing toward the suction port 42 of the pump 40. The standing wall portion 65 is provided, for example, near an end of the third bottom surface portion 63 between the pressure regulator 50 and the pump 40. In addition, a plurality of fins, a lattice-shaped portion, or the like may be provided on the third bottom surface portion 63 to rectify and break bubbles in the liquid fuel from the pressure regulator 50.

[0041] Although the description of the embodiment is now complete, aspects of the present invention are not limited to this embodiment. For example, in this embodiment, the third bottom surface portion 63 is provided above the suction port 42 of the pump 40, on a side of the pump 40 different from the side on which the suction port 42 is formed, and below the pressure regulator 50. However, the third bottom surface portion 63 may be provided at another location on the lower case 22 as long as it is above the first bottom surface portion 61 and the second bottom surface portion 62. The third bottom surface portion 63 is preferably formed around the pump 40, for example, and more preferably at any corner of the lower case 22. [Explanation of symbols]

[0042] 1 outboard motor 3. Engine (internal combustion engine) 10 Vapor Separator Tank (VST) 20 Casing 22 Lower case 22a Drain piping 24 Upper Case 25 corner part 26 Fuel storage chamber 28, 281 Mounting part 30 Float mechanism 40 Pump 42 Intake port 50 Pressure Regulator 60 Bottom part 61 1st bottom part 62 2nd bottom part 63 3rd bottom part 70 Side wall 80 filters 91 First Space 92 Second Space

Claims

1. A vapor separator tank mounted on an outboard motor to separate gas from liquid fuel supplied to an internal combustion engine, a casing having a lower case and an upper case joined to each other, the casing having a fuel storage chamber for storing the liquid fuel; a pump that pumps the liquid fuel stored in the fuel storage chamber; a pressure regulator disposed in the fuel storage chamber and configured to adjust the discharge pressure of the pump to a constant value; Equipped with the lower case is provided with a plurality of mounting portions that are attached to the internal combustion engine and a drain pipe that discharges the liquid fuel from the fuel storage chamber, the lower case includes a first bottom surface portion including a lowermost surface, a second bottom surface portion formed above the first bottom surface portion and supporting the pump, and a third bottom surface portion formed above the first bottom surface portion and the second bottom surface portion. Vapor separator tank.

2. The vapor separator tank according to claim 1 , wherein the drain pipe is provided below the second bottom portion.

3. 2. The vapor separator tank according to claim 1, wherein the third bottom surface portion is located forward of the outboard motor with respect to a first center line of the lower case and at a corner portion on either the left or right side of the outboard motor with respect to a second center line of the lower case that is perpendicular to the first center line.

4. The vapor separator tank according to any one of claims 1 to 3, wherein the third bottom surface portion is located below the pressure regulator and to the side of the pump.

5. The vapor separator tank according to claim 1 , wherein the third bottom surface portion is located above a suction port of the pump.

Images