JP4710861B2 - Fuel supply structure - Google Patents

Description

  The present invention relates to a fuel supply structure for supplying fuel in a fuel tank provided in an automobile or the like to an engine.

  Conventionally, in a vehicle such as an automobile, a fuel supply device that supplies fuel in the fuel tank to the engine is provided between the fuel tank and the engine. Such a fuel supply device mainly includes a fuel supply path connecting the fuel tank and the engine, a fuel intake path (hose or pipe) disposed in the fuel tank and connected to the fuel supply path, It is composed of a filter provided at the fuel suction port at the tip of the hose, a fuel pump for sucking and pressurizing fuel in the fuel tank, and the like.

As a technique relating to such a fuel supply device, for example, Patent Document 1 discloses a technique in which a plurality of filters are provided in parallel in a fuel tank in consideration of vehicle inclination and turning.
Japanese Utility Model Publication No. 63-492

  By the way, for example, in a fuel tank formed relatively long in the front-rear direction, it is conceivable to provide a plurality of filters in the front-rear direction as a countermeasure against engine stall during forward tilt parking. Here, in FIGS. 5A and 5B, 101 is a main filter (rear filter) provided at the rear of the fuel tank 110, and 102 is a sub-filter provided at the front of the main filter 101. (Front side filter) 103a and 103b are both hoses, 104 is a drain hose for returning surplus fuel to the fuel tank 110, and 105 is a filter provided at the tip of the drain hose 104.

Further, as shown in the figure, the front filter 102 is disposed at a position higher than the rear filter 101, and the rear filter 101 is provided near the bottom surface of the fuel tank 110.
The front filter 102 and the rear filter 101 are connected in series, and a negative pressure of a fuel pump (not shown) first acts on the rear filter 101. When the rear filter 101 cannot suck in the fuel, the negative pressure is reduced to the front side. It acts on the filter 102. Therefore, the fuel is normally sucked from the rear filter 101 and the fuel is not sucked from the front filter 102.

On the other hand, when the vehicle is leaning forward so that the front side of the vehicle faces downward, if the amount of fuel is small, the fuel cannot be sucked from the rear filter 101 as shown in FIG. 5B. In such a case, the front filter The fuel is sucked from the fuel tank 102 so that the fuel can be reliably supplied even when the fuel tank 110 is inclined.
By the way, there are some regions where fuels with properties that freeze at about −14 ° C. are circulating even though the outside air temperature is −25 ° C. or lower. In some areas where such a refueling infrastructure is not in place, when the temperature in the fuel tank 110 becomes low and the fuel approaches the freezing temperature, the viscosity of the fuel increases and paraffin precipitates from the fuel to cause the filter 101. There is a risk of blocking the mesh.

Thus, when the viscosity of the fuel increases or the paraffin adheres to the filter 101, the resistance passing through the filter 101 increases, and the fuel cannot be sufficiently sucked from the rear filter 101.
On the other hand, since the sub-filter 102 provided on the front side is merely connected in series with the rear main filter 101, if the rear filter 101 becomes clogged, the negative pressure of the fuel suction is increased on the front side. The fuel is sucked from the filter 102 on the front side.

However, in the state shown in FIG. 5A, that is, when the remaining amount of fuel is relatively small and the front filter 102 is exposed, air (air) instead of fuel from the front filter 102. Inhaling the engine, which may adversely affect the drivability of the engine and may cause an engine stall.
The technique disclosed in Patent Document 1 only discloses that the filter mesh may be appropriately determined according to the properties of the liquid fuel, the suction force of the fuel pump, and the like. Could not be resolved.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a fuel supply structure in which air is not sucked even if a filter is clogged or the like due to freezing of fuel or the like.

Therefore, the fuel supply structure of the present invention is a fuel supply structure for supplying the fuel in the fuel tank to the engine, the first suction filter provided in the fuel tank, and the first suction filter in the fuel tank. A second suction filter disposed in a position spaced apart from the first suction filter and connected in series with the first suction filter via a fuel supply passage, and the fuel tank is mounted on the engine The first suction filter is disposed at a position behind and lower than the second suction filter, and the two suction filters are either one of the two suction filters. A fuel suction hole for sucking the fuel, and a float valve for closing the fuel suction hole when the liquid level of the fuel is lower than the opening of the fuel suction hole. In addition, the first suction filter is formed with an orifice that serves both as a function of opening the fuel suction hole to the atmosphere and as a function of sucking the fuel, and above the float valve of the second suction filter. The second suction filter is characterized in that a hole for releasing air inside the second suction filter is formed.

Preferably, the air vent hole is formed only in the second suction filter and is not formed in the first suction filter . The fuel tank is connected to a fuel recirculation path for recirculating surplus fuel supplied to the engine, and is provided near the first suction filter and at the tip of the fuel recirculation path. It is preferable that a filter is provided (claim 3).

According to the fuel supply structure of the present invention, it is possible to reliably prevent air from being sucked when the fuel is frozen, and it is possible to reliably prevent deterioration of drivability and engine stall due to air sucking. Further, this can improve the reliability and safety of the vehicle.
Further, the fuel component that has not been frozen can be sucked from the orifice, and the minimum amount of fuel can be supplied to the engine.

Further, since the inside of the suction filter can be opened to the atmosphere by the orifice, sticking of the float valve due to negative pressure can be reliably avoided after the remaining amount of fuel is reduced. Further, since the second suction filter is provided with an air vent hole, the float valve can be quickly raised without hindering the rise of the float valve when refueling . Further, engine stall at the time of forward lean parking can be avoided reliably (above, claim 1).

In addition, since this air vent hole is not provided in the first suction filter, it is possible to reliably avoid a situation in which air is sucked from the relief hole during normal operation (claim 2) .

  Hereinafter, a fuel supply structure according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing the overall configuration, and FIG. FIG. 3 is a schematic perspective view showing a first suction filter as its main configuration, and FIGS. 4A and 4B are schematic cross-sectional views of the first suction filter. It is a figure explaining the effect | action of a float valve.

  In FIG. 1, reference numeral 20 denotes an engine mounted on the vehicle. The engine 20 is connected to a fuel tank 10 by a fuel supply passage 3 and a fuel return passage (drain hose) 4, and the fuel supply passage 3 is connected to a fuel pump 24 attached to the engine 20. When the fuel pump 24 is operated, the fuel in the fuel tank 10 is supplied to the engine 20 through the fuel supply passage 3, and surplus fuel is returned to the fuel tank 10 through the fuel return path 4. Yes. Reference numeral 5 denotes a filter provided at the tip of the drain hose 4.

  The fuel tank 10 is formed relatively long in the front-rear direction (vehicle length direction), similar to that described with reference to FIGS. The bottom of the fuel tank 10 has a flat rear side (rear side bottom 10a) and is inclined so that the front side gradually rises toward the front end (front side bottom 10b). Two suction filters 1 and 2 are provided in the fuel tank 10 so as to be separated from each other in the front-rear direction. A series of suction hoses 3 b constituting a part of the fuel supply passage 3 are connected between the suction filters 1 and 2. It is connected to the.

  A rear suction filter (first suction filter) 1 disposed on the rear side in the front-rear direction is connected to the middle of the fuel supply passage 3 (between the suction hoses 3a and 3b constituting a part of the fuel supply passage 3). ing. A front suction filter (second suction filter) 2 disposed on the front side in the front-rear direction is connected to an end portion of the fuel supply passage 3 (end portion of the suction hose 3b). The rear suction filter 1 is connected to a filter 25 provided outside the fuel tank 10 via a suction hose 3a. The filter 25 and the engine-driven fuel pump 24 are connected by a fuel supply path 3c.

  The front suction filter 2 is disposed on the front bottom 10 b of the fuel tank 10, and the rear suction filter 1 is disposed on the rear bottom 10 a of the fuel tank 10. Therefore, the front suction filter 2 is higher than the rear suction filter 1 when the fuel tank 10 is disposed horizontally, such as when the vehicle is traveling on a flat land or stopped on a flat land. It is in a state provided at a position.

With such a configuration, even when the vehicle is tilted forward, fuel can be sucked from the front suction filter 2 (see FIG. 5B), and engine stall at the time of forward tilt parking can be prevented. It can be done.
Next, the configuration of the main part of the present apparatus will be described. As shown in FIGS. 2 and 3, when comparing both suction filters 1 and 2, the front suction filter 2 has a relief hole 16 but no orifice, and the rear side. The suction filter 1 differs greatly in that it has an orifice 15 but does not have a relief hole 16, but the other parts are configured in substantially the same manner. In this embodiment, the front-side suction filter 2 and the rear-side suction filter 1 are configured as float-type suction filters that can seal the suction holes of the suction filters 1 and 2 and prevent air from being sucked in when there is no fuel. .

First, the configuration of the rear suction filter 1 will be described with reference to FIGS. 3 and 4.
As shown in FIG. 3 and FIGS. 4A and 4B, the rear suction filter 1 has a filter body 6 whose outer shape is substantially cylindrical. A plurality of mesh openings 6 a are formed in the outer peripheral wall portion of the filter body 6. The filter body 6 is integrally formed so as to rise from the filter bottom 7. A space 14 (see FIG. 4) through which fuel can pass is formed inside the filter bottom 7. As shown in FIGS. 4A and 4B, a fuel suction hole 8 is formed inside the filter body 6. The fuel suction hole 8 communicates the inside of the filter body 6 and the space 14 inside the filter bottom 7.

  The rear suction filter 1 includes a first suction hose connection portion (hereinafter, simply referred to as a first connection portion) 9 and a second suction hose connection portion (hereinafter, referred to as “first connection portion”) that rise from the filter bottom 7 on the side of the filter body 6. The second connection portion 11 is simply formed. These connection parts 9 and 11 are pipe-shaped, the 1st connection part 9 is connected to the suction hose 3a, and the 2nd connection part 11 is connected to the suction hose 3b. The inside of the filter main body 6 communicates with these connecting portions 9 and 11 through the fuel suction hole 8 and the space 14 in the filter bottom portion 7.

  A float (float valve) 12 made of a material having a specific gravity smaller than that of the fuel is provided inside the filter body 6. The float 12 is lowered and raised as the liquid level of the fuel introduced into the filter body 6 is lowered and raised. As a result, as shown in FIG. 4 (b), when the fuel amount is reduced and the liquid level is lowered, the float 12 is also lowered. When the fuel level is lower than the opening of the fuel suction hole 8, the float 12 The fuel suction hole 8 is closed. In FIG. 4, reference numeral 13 denotes a seal member (seal ring) for improving liquid tightness.

  Further, the rear suction filter 1 is provided with an orifice 15 that communicates the space 14 inside the filter bottom 7 with the outside. The orifice 15 is a small-diameter hole provided only in the rear suction filter 1 and is not provided in the front suction filter 2. The orifice 15 has a main function of preventing the float 12 from being kept in close contact with the seal member 13 when the remaining amount of fuel in the fuel tank 10 is reduced and the float 12 is in close contact with the seal member 13. The details will be described later.

Next, the configuration of the front suction filter 2 will be described with reference to FIG.
As shown in FIG. 2, the front suction filter 2 is the same as the rear suction filter 1 described above in that it includes a filter body 6, a filter bottom portion 7, both connection portions 9 and 11, a float 12, and the like. The connection part 9 is sealed and only the second connection part 11 functions, the relief hole 16 for air escape is formed on the upper surface of the filter body 6, and the orifice is not formed. It differs greatly from the rear suction filter 1. The relief hole 16 is provided only in the front suction filter 2 and is not formed in the rear suction filter 1 (see FIG. 3). The relief hole 16 is used to surely discharge the air remaining in the filter body 6, and details thereof will be described later.

  In such a fuel supply structure, when the liquid level of the fuel in the fuel tank 10 is above the opening of the fuel suction hole 8 of the rear suction filter 1, the fuel is sucked from the rear suction filter 1. At this time, when the fuel passes through the mesh-shaped opening 6a of the filter body 6, foreign matters mixed in the fuel are removed. Thereafter, the fuel is sucked into the space 14 of the filter bottom 7 from the fuel suction hole 8 of the filter body 6 and supplied to the engine 20 through the suction hose 3a.

  As described above, the two suction filters 1 and 2 are both float-type suction filters, so that when the fuel level is lower than that of the front suction filter 2, the front suction filter 2 uses the float 12 to generate fuel. Since the suction hole 8 is closed, it is possible to reliably avoid a situation where air is sucked from the front suction filter 2.

In particular, the fuel liquid level is lower than the front filter 2 and higher than the rear filter 1, and the outside air temperature (eg, −25 ° C.) below the fuel freezing temperature (eg −14 ° C.). In this case, this float filter functions effectively.
In other words, in this case, the viscosity of the fuel increases due to freezing, and paraffin precipitates from the fuel and closes the mesh of the opening 6a of the rear suction filter 1, so that the fuel is sufficiently sucked from the rear suction filter 1. Disappear. When the rear suction filter 1 is clogged in this way, the negative pressure of fuel suction acts on the front suction filter 2 and tries to suck air from the front suction filter 2.

However, in this case, since the fuel suction hole 8 of the front suction filter 2 is closed by the float 12 described above, a situation in which the front suction filter 2 sucks ambient air can be avoided, and engine stall or the like can be prevented. can do.
Further, in this case, the fuel is sucked by the negative pressure acting on the rear suction filter 1 even from a small gap in the mesh of the rear suction filter 1 and can be supplied to the engine 20. It becomes like this.

As in the prior art, if the fuel tank 10 is parked in a forward leaning posture such that the fuel tank 10 is lowered forward, even if the fuel suction hole 8 of the rear filter 1 protrudes above the fuel level, Fuel can be sucked from the front filter 2 to prevent the engine from stalling.
By the way, in this embodiment, since the two front and rear suction filters 1 and 2 are both configured as float-type suction filters, if the fuel level is lower than the rear suction filter 1, both suction filters 1 2, the fuel suction hole 8 is blocked by the float 12, and when the fuel pump 24 stops in this situation, the negative pressure remains applied, and the float 12 adheres to the seal member 13 (that is, It may be stuck).

  Therefore, in the rear suction filter 1, a small-diameter orifice 15 is formed in the filter main body 6, and the orifice 15 communicates the space 14 in the fuel tank 10 and the filter bottom 7, so that the space 14 is formed. It is intended to be released to the atmosphere. Then, the space 14 is opened to the atmosphere through the orifice 15 to eliminate sticking of the float 12 to the seal member 13.

The diameter of the orifice 15 is set to such a size that the float 12 can be in close contact with the seal member 13 when a negative pressure is applied, and the sticking of the seal member 13 of the float 12 can be eliminated when the negative pressure stops working. In the case of the present embodiment, it is set to about Φ1.0 to 2.0, for example.
By providing such an orifice 15, it is possible to prevent sticking of the float 12 when fuel is supplied to the fuel tank 10 while preventing air from being sucked in, and to open the fuel suction hole 8 immediately after fuel supply. Further, by providing such an orifice 15, there is an advantage that a small amount of fuel can be sucked from the orifice 15 and a large amount of fuel can be sucked when the fuel is frozen or paraffin is deposited.

  Such an orifice 15 is necessary because the front suction filter 2 is a float suction filter, and if the front suction filter 2 is a general suction filter that is always open to the atmosphere, Since the rear suction filter 1 is also opened to the atmosphere via the front suction filter 2, such an orifice 15 is unnecessary.

  Furthermore, if paraffin adheres to the mesh of the filter body 6 of the front suction filter 2, the air in the filter body 6 remains without being discharged from the mesh when the fuel is supplied to the fuel tank 10. Although the floating may be hindered by the residual air, the air remaining in the filter body 6 can be surely discharged by the relief hole 16 for releasing air. Then, the air remaining in the filter body 6 at the time of refueling is discharged from the relief hole 16, so that the float 12 can be promptly levitated.

However, if such a relief hole 16 is provided in the rear suction filter 1, air may be sucked from the relief hole 16 during normal operation. For this reason, the rear suction filter 1 eliminates the relief holes to prevent air suction more reliably.
Since the fuel supply structure according to the embodiment of the present invention is configured as described above, fuel is sucked by the rear suction filter 1 and supplied to the engine 20 during normal operation. On the other hand, if the fuel tank 10 tilts forward due to forward lean parking when the remaining amount of fuel is small, fuel cannot be sucked from the rear suction filter 1, but in this case, fuel is supplied by the front suction filter 2. , Engine stall is avoided.

By the way, the fuel component should be adjusted so that it does not freeze unless the temperature is lower than the lowest temperature expected in the area where it is used. In the region, fuel that freezes at a temperature higher than the outside air temperature (about −14 ° C.) is circulating.
In some areas where the refueling infrastructure is not in place, when the fuel tank 10 becomes cold and the fuel approaches the freezing temperature, the viscosity of the fuel increases and paraffin precipitates from the fuel. 6 may be blocked, and a situation may occur where fuel cannot be sufficiently sucked from the rear suction filter 1.

In this case, the negative pressure of the fuel suction acts on the front suction filter 2 and the fuel is sucked from the front suction filter 2. In such a case, the remaining amount of fuel is reduced, and the front suction filter If 2 is exposed from the fuel surface, air may be sucked from the front suction filter 2.
On the other hand, in the fuel supply device according to the present embodiment, since the fuel supply hole 8 of the front suction filter 2 is closed by the float 12, it is possible to reliably prevent such air suction. Thereby, deterioration of drivability and engine stall due to air suction can be prevented, and the reliability and safety of the vehicle can be improved.

Further, in this case, since a large negative pressure acts on the rear suction filter 1, fuel components that have not been frozen can be sucked from the fuel supply hole 8 and the orifice 15 of the rear suction filter 1. The fuel can be supplied.
In normal use, when the fuel is used up, the float 12 closes the fuel supply hole 8 in both the suction filters 1 and 2. In this fuel supply structure, however, the filter is passed through the orifice 15 of the rear suction filter 1. Since the space 14 in the bottom portion 7 can be opened to the atmosphere, the close contact (sticking) of the float 12 to the seal member 13 due to negative pressure can be reliably avoided.

  Further, since the air vent relief hole 16 is provided on the upper surface of the filter main body 6 of the front suction filter 2, the float 12 can be quickly raised when refueling. Since the relief hole 16 is not provided in the rear suction filter 1, it is possible to reliably avoid a situation in which the rear suction filter 1 sucks air during normal operation.

  Although the embodiments of the present invention have been described above, the present invention is not limited to such embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, in the above-described embodiment, the orifice 15 is provided only in the rear suction filter 1, but an orifice may be added to the front suction filter 1. Further, in the present embodiment, the fuel tank 10 is shaped so as to extend in the front-rear direction of the vehicle. In this case, by arranging the two suction filters so as to be separated from each other in the left-right direction, the same effect as described above can be obtained with respect to the fuel bias accompanying the inclination of the vehicle in the left-right direction.

It is a mimetic diagram showing the whole fuel supply structure composition concerning one embodiment of the present invention. It is a typical perspective view showing the 2nd suction filter as the principal part composition of the fuel supply structure concerning one embodiment of the present invention. It is a typical perspective view showing the 1st suction filter as the principal part composition of the fuel supply structure concerning one embodiment of the present invention. It is a typical sectional view of the 1st suction filter in the fuel supply structure concerning one embodiment of the present invention, and is a figure explaining the operation of a float valve. It is a figure explaining the prior art.

Explanation of symbols

1 Rear suction filter (first suction filter)
2 Front suction filter (second suction filter)
3 Fuel Supply Passage 3a, 3b Suction Hose 6 Filter Body 6a Opening 7 Filter Bottom 8 Fuel Suction Hole 10 Fuel Tank 12 Float (Float Valve)
15 Orifice 16 Relief hole (Air vent hole)
20 engine

Claims (3)

A fuel supply structure for supplying fuel in a fuel tank to an engine,
A first suction filter provided in the fuel tank;
A second suction filter disposed in a position spaced apart from the first suction filter in the fuel tank and connected in series with the first suction filter via a fuel supply passage;
The fuel tank is formed so as to extend in the front-rear direction of a vehicle on which the engine is mounted, and the first suction filter is disposed at a rear and lower position than the second suction filter. And
Each of the two suction filters includes a fuel suction hole for sucking the fuel, and a float valve for closing the fuel suction hole when the liquid level of the fuel is lower than the opening of the fuel suction hole.
The first suction filter is formed with an orifice that has both a function of opening the fuel suction hole to the atmosphere and a function of sucking the fuel,
A fuel supply structure, wherein a hole for allowing air inside the second suction filter to escape is formed above the float valve of the second suction filter. 2. The fuel supply structure according to claim 1, wherein the air vent hole is formed only in the second suction filter and is not formed in the first suction filter. The fuel tank is connected to a fuel return path for returning excess fuel supplied to the engine, and is provided at the tip of the fuel return path in the vicinity of the first suction filter. A filter is installed
The fuel supply structure according to claim 1, wherein the structure is a fuel supply structure.

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