JP2008038695A - Three-way valve for fuel supply device - Google Patents

Abstract

To prevent return fuel from leaking into a feed line at a high fuel temperature.
The present invention is a fuel supply device three-way valve 60 for supplying fuel flowing through a return line 2 of a fuel supply device 100 to a feed line 1 of the fuel supply device 100 according to the fuel temperature. The main passage 61 through which the fuel flowing through the return line 2 passes, the bypass passage 62 communicating with the main passage 61 and the feed line 1, the lip portion 68 projecting from the opening end 62a of the bypass passage 62, and the fuel temperature can be increased or decreased. Accordingly, the bimetal 63 is deformed to be convex on the upper surface or convex on the lower surface, and closes the opening end 62a by contacting the lip 68 when the fuel temperature is high, and prevents the fuel from leaking into the bypass passage 62. It is characterized by having.
[Selection] Figure 3

Description

  The present invention relates to a three-way valve for a fuel supply device.

  Diesel engines have long been used as engines for automobiles and the like. Diesel engines use light oil as fuel. Light oil has the property that, when cooled, the wax in its components separates and condenses. For this reason, when inappropriate gas oil is used in a low temperature environment such as a cold region, wax is precipitated. When such a large amount of wax is deposited, the fuel filter element disposed in the feed line is clogged. As a result, fuel may not flow and the engine may stop.

  Therefore, it is necessary to ensure fuel fluidity even in a low temperature environment. Therefore, when the fuel temperature (hereinafter referred to as “fuel temperature”) is low (at low fuel temperature), part of the return fuel returned from the fuel pump to the fuel tank through the return line is passed through the fuel filter. Return to the feed line. The return fuel is pressurized by the fuel pump and has a high temperature. Therefore, the fuel temperature can be raised by mixing the return fuel with the fuel (fuel in the feed line) from the fuel tank passing through the fuel filter through the fuel filter. Thereby, precipitation of wax can be prevented.

  On the other hand, if return fuel is supplied to the feed line at a high fuel temperature, the fuel temperature in the feed line rises. If it does so, rail pressure cannot be raised and an output will fall. Therefore, at a high fuel temperature, it is desirable to return the return fuel to the fuel tank without supplying it to the feed line.

Therefore, a bimetal type three-way valve for switching whether to supply return fuel to the feed line according to the fuel temperature is known (for example, Patent Document 1).
Japanese Patent Application Laid-Open No. 60-142048

  However, the conventional three-way valve sometimes leaks return fuel to the feed line at a high fuel temperature.

  The present invention has been made paying attention to such a conventional problem, and prevents return fuel from leaking into the feed line at a high fuel temperature.

  The present invention is a three-way valve for a fuel supply device that supplies fuel flowing through a return line of a fuel supply device to a feed line of the fuel supply device in accordance with the level of the fuel temperature. A passage, a bypass passage communicating with the main passage and the feed line, a lip portion protruding from an opening end of the bypass passage, and a convexity on the upper surface or a convexity on the lower surface depending on the fuel temperature, A bimetal that abuts against the lip portion when the fuel temperature is high and closes the opening end to prevent fuel from leaking into the bypass passage.

  According to the present invention, by providing the bimetal with a sealing function, the fuel can be sealed without being affected by the fuel pressure, and the return fuel can be prevented from leaking to the feed line at a high fuel temperature.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic view of a fuel supply apparatus 100 according to the present invention. The fuel supply device 100 includes a fuel tank 10, a fuel filter 20, an injection pump 30, a common rail 40, and an injector 50.

  The fuel supply device 100 includes two fuel paths, a feed line 1 and a return line 2. The feed line 1 is a fuel path for sending the fuel in the fuel tank 10 to the engine. The return line 2 is a fuel path for returning excess fuel (hereinafter referred to as “return fuel”) out of the sent fuel to the fuel tank 10. Return paths 2 a and 2 b are connected to the return line 2. The return passage 2 a returns the surplus fuel of the injection pump 30 to the return line 2. The return passage 2 b returns the leaked fuel leaking from the injector 50 to the return line 2.

  The fuel supply device 100 filters the fuel in the fuel tank 10 through the fuel filter 20 and sends the fuel to the injection pump 30, and injects the fuel from the injector 50 into the combustion chamber via the common rail 40. The fuel injection amount and injection time are controlled by a controller (not shown) in accordance with the operating state of the engine.

  The fuel tank 10 stores fuel to be injected into the combustion chamber of the engine. A jet pump 11 is disposed in the fuel tank 10. The jet pump 11 uses the return fuel from the engine as the working fluid and transfers the fuel from the sub tank 10b of the fuel tank 10 to the main tank 10a.

  The injection pump 30 sucks the fuel in the fuel tank 10 through the fuel filter 20, compresses the sucked fuel to a high pressure, and pumps the fuel to the common rail 40. The injection pump 30 includes a metering valve that adjusts the amount of fuel to be sucked. This metering valve is controlled by a controller to adjust the common rail pressure.

  The common rail 40 accumulates the high-pressure fuel pumped from the injection pump 30 and supplies the accumulated high-pressure fuel to the injector 50. A pressure relief valve 41 is provided in the return line 2 that returns the fuel from the common rail 40 to the fuel tank 10. The pressure relief valve 41 opens when the common rail pressure exceeds the limit set pressure, and keeps the common rail pressure below the limit set pressure.

  The injector 50 is mounted for each cylinder of the engine, and injects high-pressure fuel accumulated in the common rail 40 into each cylinder. The injector 50 is connected to the return line 2 via the return passage 2b in order to return the leaked fuel leaking from the injector 50 to the fuel tank 10.

  The fuel cooler 70 cools the return fuel. The fuel cooler 70 is disposed in the return line 2 connected to the fuel tank 10.

  The fuel filter 20 removes dust, moisture, wax and the like in the fuel. In particular, light oil used as fuel for diesel engines has the property of depositing wax when cooled. For this reason, when inappropriate gas oil is used in a low temperature environment such as a cold region, wax is precipitated in the fuel. When such a large amount of wax precipitates, the element of the fuel filter 20 is clogged. As a result, fuel may not flow and the engine may stop.

  Therefore, it is necessary to ensure fuel fluidity even in a low temperature environment. Therefore, at the time of low fuel temperature, a part of the return fuel pressurized by the injection pump 30 and having a high temperature is returned to the feed line 1 via the bypass passage 62 that passes through the fuel filter 20. The fuel temperature can be raised by mixing the return fuel with the fuel from the fuel tank 10 passing through the fuel filter 20 (fuel in the feed line 1). Thereby, precipitation of wax can be prevented.

  On the other hand, when a part of the return fuel is returned to the feed line 1 via the bypass passage 62 passing through the fuel filter 20 at the high fuel temperature, the fuel temperature in the feed line 1 rises. If the fuel temperature is high, the common rail pressure cannot be increased, and the output decreases. Therefore, it is desirable to return the return fuel to the fuel tank 10 without returning it to the feed line 1 at a high fuel temperature.

  Therefore, the fuel supply device 100 includes a three-way valve 60 that is positioned above the fuel filter 20 and controls whether or not the return fuel is returned to the feed line 1 according to the fuel temperature.

  The present invention relates to an improvement of this three-way valve. In order to facilitate understanding of the present invention, first, the configuration of the conventional three-way valve 600 will be described.

  13 and 14 are schematic views showing the configuration of a conventional three-way valve 600. FIG. FIG. 13 is a view showing a state of the three-way valve 600 at the time of low fuel temperature. FIG. 14 is a view showing a state of the three-way valve 600 at a high fuel temperature. In addition, the arrow in a figure shows the flow of return fuel.

  The three-way valve 600 includes a main passage 661 for passing fuel in the return line 2, a bypass passage 662 leading to the feed line 1, a bimetal 663 for switching whether or not the fuel flowing through the return line 2 is returned to the feed line 1, and a feed And a check valve 665 for sealing fuel to the line 1.

  An inlet 661 a and an outlet 661 b of the main passage 661 are connected to the return line 2.

  The bypass passage 662 is connected to the feed line 1 in the fuel filter 20.

  The bimetal 663 is a thin disk-shaped plate. The bimetal 663 is not fixed in the three-way valve 600, and its shape changes into unevenness due to heat. The shape of the bimetal 663 changes upward in the drawing at a low fuel temperature (see FIG. 13). On the other hand, the shape of the bimetal 663 changes in a convex manner downward in the drawing when the fuel temperature is high (see FIG. 14). In this way, the bimetal 663 switches whether to supply the fuel flowing through the return line 2 to the feed line 1.

  The check valve 665 seals so that fuel does not leak from the main passage 661 to the bypass passage 662. The check valve 665 opens when the fuel pressure exceeds a predetermined valve opening pressure, and returns the high-temperature return fuel flowing through the return line 2 to the feed line 1.

  As shown in FIG. 13, the shape of the bimetal 663 is deformed so as to protrude upward in the drawing when the fuel temperature is low, and the return fuel flowing in from the inlet 661a of the main passage 661 passes through the gap on the outer periphery of the bimetal 663 to the bypass passage. It is introduced on the 662 side. The check valve 665 opens when the fuel pressure exceeds a predetermined valve opening pressure. Then, the return fuel merges with the fuel flowing through the feed line 1 through the bypass passage 662.

  On the other hand, as shown in FIG. 14, the bimetal 663 is deformed so as to protrude downward in the drawing at a high fuel temperature, and introduces return fuel flowing from the inlet 661 a of the main passage 661 into the outlet 661 b of the main passage 661. Since the bimetal 663 is not fixed inside the three-way valve 600, the bimetal 663 does not have a function of positively sealing fuel with the inner wall surface 600b of the three-way valve 600. Therefore, at the time of high fuel temperature, the check valve 665 seals the fuel that is about to leak to the bypass passage 662 side.

  The check valve 665 needs to prevent fuel from leaking to the bypass passage 662 without opening even when a large amount of return fuel is generated at a high fuel temperature. On the other hand, when the fuel temperature is low, it is necessary to open the valve even when the amount of return fuel is small and introduce the return fuel into the bypass passage 662.

  As described above, in the structure of the conventional three-way valve 600, the reverse performance at the low fuel temperature and the high fuel temperature is reversed with respect to the check valve 665 that performs fuel sealing (the amount of return fuel is large at the high fuel temperature (high Even when the fuel pressure is low), the valve is closed, and at low fuel temperature, the return fuel is required even if the return fuel is small (low fuel pressure). However, since it is impossible to completely satisfy such mutually conflicting requirements, it is necessary to set the valve opening pressure in consideration of the balance between the two.

  Therefore, even at the high fuel temperature, when the fuel pressure exceeds a predetermined valve opening pressure, the check valve 665 is opened, and the return fuel may merge with the fuel flowing through the feed line 1 through the bypass passage 662. When a part of the return fuel is returned to the feed line 1 through the fuel filter 20 at the high fuel temperature, the fuel temperature in the feed line 1 rises. If the fuel temperature is high, the rail pressure cannot be increased, which causes a problem that the output decreases. In addition, it is necessary to change the set value of the valve opening pressure according to the specifications and settings for each vehicle (for example, the absolute amount of return fuel and the specifications of the fuel cooler 70 and the like existing in the return line 2). Therefore, each time there was a problem because a confirmation test was required.

  Therefore, the present invention provides a three-way valve that is not affected by securing a stable seal pressure, specifications of each vehicle, and the like by providing a bimetal with a sealing function.

  2 and 3 are schematic views showing the configuration of the three-way valve 60 according to the present invention. FIG. 2 is a view showing the state of the three-way valve 60 at the time of low fuel temperature. FIG. 3 is a view showing a state of the three-way valve 60 at the time of high fuel temperature.

  Similar to the conventional three-way valve 600, the three-way valve 60 has a main passage 61 for passing fuel in the return line 2, a bypass passage 62 leading to the feed line 1, and a fuel flowing through the return line 2 in the housing 60a. A bimetal 63 that switches whether to recirculate to 1, and a check valve 65 that seals fuel to the feed line 1.

  Further, the three-way valve 60 according to the present invention forms a sealing surface between the two O-rings 66 and 67 for fixing the bimetal 63 and the bimetal 63 with respect to the conventional three-way valve 600 to seal the fuel. Resin lip portions 68 and 69 are added.

  The bimetal 63 has a communication hole 63a through which fuel passes. There may be a plurality of communication holes 63a. The bimetal 63 is fixed in the three-way valve 60 with the circumferential part held between both sides by O-rings 66 and 67. In the bimetal 63, the shape of the central portion is deformed into irregularities according to the fuel temperature, with the circumferential portion held by the O-rings 66 and 67 as a fulcrum.

  The resin lip portions 68 and 69 project from a discharge port 61 c connected to the main passage 61 on the outlet 61 a side and an introduction port 62 a connected to the bypass passage 62. The resin lip portions 68 and 69 are arranged on both sides of the bimetal 63 in a space 64 where the bimetal 63 changes.

  Therefore, the bimetal 63 is pressed against the resin lip portions 68 and 69. That is, the elastic force of the bimetal 63 acting on the resin lip portions 68 and 69 can be used as the fuel seal pressure. Thereby, the resin lip portions 68 and 69 and the bimetal 63 come into contact with each other to form the sealing surfaces 68a and 69a, and a stable sealing pressure can be secured. Further, the bimetal 63 can follow the deterioration of the resin lip portions 68 and 69 by an elastic force. Therefore, a stable sealing pressure can be ensured even when the resin lip portions 68 and 69 deteriorate.

  As shown in FIG. 2, the shape of the bimetal 63 is deformed upward in the drawing at the low fuel temperature, and comes into contact with the resin lip 69. The bimetal 63 introduces return fuel flowing from the inlet 61a of the main passage 61 to the bypass passage 62 side through the communication hole 63a. At that time, the check valve 65 opens when the fuel pressure exceeds a predetermined valve opening pressure. Then, the return fuel merges with the fuel flowing through the feed line 1 through the bypass passage 62.

  On the other hand, as shown in FIG. 3, when the fuel temperature is high, the bimetal 63 is deformed so as to protrude downward in the figure, and introduces return fuel flowing from the inlet 61 a of the main passage 61 into the outlet 61 b of the main passage 61. At that time, the bimetal 63 abuts on the resin lip portion 68 and seals fuel that is about to leak into the bypass passage 62. In the unlikely event of leakage, the check valve 65 further seals the fuel.

  As described above, the bimetal 63 introduces the return fuel flowing from the inlet 61a of the main passage 61 to the bypass passage 62 side when the fuel temperature is low. At this time, in the conventional three-way valve 600 shown in FIGS. 13 and 14, the return fuel flows into the fuel passage 162 side through the gap between the outer periphery of the bimetal 663 and the inner wall surface 600 b of the three-way valve 600. This gap was small, and the pressure loss of the return fuel was large at low fuel temperature.

  On the other hand, in the three-way valve 60 according to the present embodiment, a communication hole 63a is provided in the bimetal 63 and introduced into the bypass passage 62 side through the communication hole 63a. Therefore, pressure loss can be reduced by adjusting the number and size of the communication holes 63a to increase the opening area of the communication holes 63a.

  Further, the conventional three-way valve 600 seals the fuel with the check valve 665 as shown in FIG. 14 at the time of high fuel temperature, but the three-way valve 60 according to the present embodiment is bimetallic as shown in FIG. 63 contacts the upper surface 68a of the resin lip portion 68 to seal the fuel. Therefore, the fuel can be sealed without being affected by the fuel pressure. Therefore, it is possible to prevent the return fuel from returning to the feed line 1 at a high fuel temperature.

  FIG. 4 is a diagram showing the relationship between the flow rate of the return fuel and the amount of leakage to the feed line 1 by comparing the three-way valve 60 according to the present invention and the conventional three-way valve 600.

  As shown in this figure, the conventional three-way valve 600 increases the amount of leakage to the feed line 1 as the flow rate of the return fuel increases. This is because when the fuel pressure exceeds a predetermined valve opening pressure, the check valve 665 that has sealed the fuel is opened.

  On the other hand, the three-way valve 60 according to the present invention hardly leaks fuel into the feed line 1 even if the flow rate of the return fuel increases. In the three-way valve 60 according to the present invention, the bimetal 63 is in close contact with the resin lip portion 68 to seal the fuel. Therefore, unlike the conventional three-way valve 600 that seals with a check valve, it is not affected by the fuel pressure.

  FIG. 5 is a graph showing the relationship between the amount of leakage of return fuel to the feed line 1 and the fuel temperature at the inlet of the injection pump 30 by comparing the three-way valve 60 according to the present invention and the conventional three-way valve 600. .

  The three-way valve 60 according to the present invention can reduce the amount of return fuel leakage to the feed line 1 compared to the conventional three-way valve 600 (see FIG. 4). By reducing the amount of high-temperature return fuel leakage, the three-way valve 60 according to the present invention can lower the fuel temperature at the inlet of the injection pump 30 compared to the conventional three-way valve 600, as shown in FIG.

  FIG. 6 is a diagram showing the relationship between the fuel temperature at the inlet of the injection pump 30 and the internal pressure of the common rail 40 by comparing the three-way valve 60 according to the present invention and the conventional three-way valve 600.

  When the fuel temperature rises, vapor is generated in the fuel. If even a small amount of vapor is included, the injection amount of the injector 50 varies greatly when high-pressure fuel is injected. As a result, injection variations occur and stable fuel injection cannot be performed. Therefore, when the fuel temperature is high, it is necessary to reduce the internal pressure of the common rail 40 to suppress the increase in the fuel temperature.

  The three-way valve 60 according to the present invention can lower the fuel temperature at the inlet of the injection pump 30 compared to the conventional three-way valve 600 (see FIG. 5). Therefore, as shown in FIG. 6, the three-way valve 60 according to the present invention can increase the internal pressure of the common rail 40 as compared with the conventional three-way valve 600.

  FIG. 7 is a view showing the relationship between the pressure in the common rail 40 and the engine output by comparing the three-way valve 60 according to the present invention with the conventional three-way valve 600.

  The three-way valve 60 according to the present invention can increase the internal pressure of the common rail 40 as compared to the conventional three-way valve 600 (see FIG. 6). Therefore, as shown in FIG. 7, the three-way valve 60 according to the present invention can increase the internal pressure of the common rail 40 and increase the engine output as compared with the conventional three-way valve 600. Note that the internal pressure of the common rail 40 is adjusted by a metering valve provided in the injection pump 30.

  According to the present embodiment described above, the bimetal 63 is nipped and fixed by the O-rings 66 and 67, and the resin lip portions 68 and 69 are provided in the space in which the bimetal 63 changes unevenly. The bimetal 63 protrudes upward at a low temperature and comes into contact with the resin lip 69 to prevent fuel from flowing into the return line 2. Further, the bimetal 63 protrudes downward at a high temperature and comes into contact with the resin lip portion 68 to prevent fuel from flowing into the feed line 1.

  Further, the bimetal 63 can follow the deterioration of the resin lip portions 68 and 69 by an elastic force. Thus, by using the elastic force of the bimetal 63 acting on the resin lip portions 68 and 69 as the fuel seal pressure, even if the resin lip portions 68 and 69 deteriorate, the bimetal 63 adheres to the resin lips 68 and 69. So do not leak fuel.

  Further, the conventional three-way valve 600 seals the fuel only by the check valve 665. Therefore, when the fuel pressure exceeds a predetermined valve opening pressure at a high fuel temperature, the check valve 665 is opened and the return fuel is recirculated to the feed line 1.

  On the other hand, according to the present embodiment, the bimetal 63 is in close contact with the resin lip portion 68 and seals the fuel when the fuel temperature is high. Therefore, the fuel can be sealed without being affected by the fuel pressure. Therefore, it is possible to prevent the return fuel from leaking to the feed line 1 when the fuel temperature is high. Furthermore, since the three-way valve 60 has a specification that is not affected by the fuel pressure, it does not affect the specifications of the fuel cooler 70, the jet pump 11, and the like that exist in the return line 2.

  Further, when the fuel temperature is low, the return fuel flowing from the inlet 61a of the main passage 61 is introduced to the bypass passage 62 side.

  At this time, in the conventional three-way valve 600, the return fuel flows into the fuel passage 162 side through the gap between the outer periphery of the bimetal 63 and the inner wall surface 600b of the three-way valve 600. This gap was small, and the pressure loss of the return fuel was large at low fuel temperature. On the other hand, according to the present embodiment, the communication hole 63a is provided in the bimetal 63, and the bimetal 63 is introduced into the bypass passage 62 through the communication hole 63a. Therefore, pressure loss can be reduced by adjusting the number and size of the communication holes 63a to increase the opening area of the communication holes 63a.

(Second Embodiment)
Next, a three-way valve 260 according to a second embodiment of the present invention will be described with reference to FIG. The three-way valve 260 according to the second embodiment of the present invention is different from the first embodiment in that a vapor passage 261 is provided. Hereinafter, the difference will be mainly described. In each of the following embodiments, the same reference numerals are used for portions that perform the same functions as those of the first embodiment described above, and repeated descriptions are omitted as appropriate.

  FIG. 8 is a schematic diagram showing the configuration of the three-way valve 260 according to the second embodiment of the present invention.

  The three-way valve 260 has a vapor passage 261 that communicates the inlet 61 a and the outlet 61 b of the main passage 61. The three-way valve 260 has a communication hole 63 a for the bimetal 63 on the outlet 61 b side of the main passage 61. The communication hole 63 a is provided below the vapor passage 261.

  As shown in FIG. 8, the bimetal 63 is in close contact with the resin lip 69 when the fuel temperature is low. At this time, since the housing 260a of the three-way valve 260 is cylindrical, the return fuel flowing from the inlet 61a passes around the resin lip portion 69 and is introduced into the bypass passage 62 from the communication hole 63a provided on the outlet 61b side. Is done.

  Here, when the vapor generated in the fuel merges with the fuel flowing through the feed line 1, the injector 50 cannot perform stable fuel injection as described above. Therefore, as in the present embodiment, the vapor passage 261 is provided on the inlet 61a side of the communication hole 63a of the bimetal 63, and further the communication hole 63a is provided below the vapor passage 261, thereby generating in the return fuel. The vapor can be positively sent to the fuel tank 10. Therefore, it becomes difficult for vapor to mix into the fuel supplied to the feed line 1 through the communication hole 63a. As a result, the vapor generated in the fuel can be prevented from being injected from the injector 50 together with the fuel. Therefore, the injector 50 can perform stable fuel injection. Moreover, the occurrence of vapor lock can be suppressed.

(Third embodiment)
Next, a three-way valve 360 according to a third embodiment of the present invention will be described with reference to FIG. The three-way valve 360 according to the third embodiment of the present invention is different from the first embodiment in that a rubber sheet 361 is attached to the resin lip portions 68 and 69. Hereinafter, the difference will be mainly described.

  FIG. 9 is a schematic view showing a configuration of a three-way valve 360 according to the third embodiment of the present invention.

  In the three-way valve 360, a rubber sheet 361 is attached to seal surfaces 68a and 69a formed by the resin lip portions 68 and 69 and the bimetal 63.

  According to the present embodiment, by attaching the rubber sheet 361 as a seal material to the fuel seal surfaces 68a and 69a, more stable fuel seal performance can be ensured when the bimetal 63 is in close contact.

(Fourth embodiment)
Next, a three-way valve 460 according to a fourth embodiment of the present invention will be described with reference to FIG. The three-way valve 460 according to the fourth embodiment of the present invention is different from the first embodiment in that rubber sheets 461 that are in contact with the resin lip portions 68 and 69 are attached to both surfaces of the bimetal 63. Hereinafter, the difference will be mainly described.

  FIG. 10 is a schematic view showing a configuration of a three-way valve 460 according to the fourth embodiment of the present invention.

  Rubber sheets 461 are attached to both surfaces of the bimetal 63 in the three-way valve 460 so as to contact the resin lip portions 68 and 69. The rubber sheet 461 is a thin disk-shaped plate.

  Thus, by forming the fuel seal surface with the resin lip portions 68 and 69 and the rubber sheet 461, more stable fuel seal performance can be secured. Note that the rubber sheet 461 may have a ring shape in accordance with the resin lip portions 68 and 69.

  Note that the present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea. For example, in each of the above embodiments, the bimetal 63 is held and fixed by the two O-rings 66 and 67. However, as shown in FIG. 11, one bi-metal 63 provided with an annular notch 561a is provided on the inner periphery. The rubber ring member 561 may be held and fixed.

  Further, in each of the above embodiments, instead of the communication hole 63a formed in the bimetal 63 as a fuel passage, a fuel passage communication passage 562 may be formed in a part of the housing 560a as shown in FIG. Good. The communication passage 562 connects the main passage 61 on the inlet 61 a side and the space 64 on the bypass passage 62 side, which are partitioned by the bimetal 63.

  In addition, although the bimetal 63 and the check valve 65 have double fuel seals, the bimetal 63 can provide a stable fuel seal, so the check valve 65 may be eliminated.

1 is a schematic view of a fuel supply apparatus 100 according to the present invention. It is the figure which showed the mode of the three-way valve by 1st Embodiment of this invention at the time of low fuel temperature. It is the figure which showed the mode of the three-way valve by 1st Embodiment of this invention at the time of high fuel temperature. It is the figure which showed the relationship between the flow volume of a return fuel, and the amount of leaks to a feed line. It is the figure which showed the relationship between the leakage amount to the feed line of a return fuel, and the fuel temperature of the injection pump inlet_port | entrance. It is the figure which showed the relationship between the fuel temperature of the injection pump inlet, and the pressure in a common rail. It is the figure which showed the relationship between the pressure in a common rail, and an engine output. It is the schematic which shows the structure of the three-way valve by 2nd Embodiment of this invention. It is the schematic which shows the structure of the three-way valve by 3rd Embodiment of this invention. It is the schematic which shows the structure of the three-way valve by 4th Embodiment of this invention. It is a figure which shows the modification of the rubber material which clamps a bimetal. It is the figure which formed the communicating path for fuel passage in the three-way valve main body. It is the figure which showed the mode of the conventional three-way valve at the time of low fuel temperature. It is the figure which showed the mode of the conventional three-way valve at the time of high fuel temperature.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Feed line 2 Return line 10 Fuel tank 60 Three-way valve 61 Main passage 61a Inlet 61b Outlet 62 Bypass passage 62a Inlet (open end)
63 Bimetal 63a Communication hole 66 O-ring (holding member)
67 O-ring (holding member)
100 Fuel supply device 261 Vapor passage 361 Rubber sheet (rubber sealing material)
461 Rubber sheet (rubber sealant)
561 Rubber ring member (holding member)

Claims (8)

A fuel supply device three-way valve that supplies fuel flowing through a return line of a fuel supply device to a feed line of the fuel supply device according to a fuel temperature level,
A main passage through which fuel flowing through the return line passes,
A bypass passage communicating the main passage and the feed line;
A lip projecting from the open end of the bypass passage;
A bimetal that deforms convexly on the upper surface or convexly on the lower surface depending on the fuel temperature level, closes the opening end by contacting the lip when the fuel temperature is high, and prevents the fuel from leaking into the bypass passage When,
A three-way valve for a fuel supply device. 2. The three-way fuel supply device according to claim 1, further comprising a vapor passage that connects an inlet-side passage and an outlet-side passage of the main passage that is partitioned by the bimetal when the fuel temperature is low. valve. The three-way valve for a fuel supply apparatus according to claim 1 or 2, wherein the bimetal has a communication hole through which fuel passes. The three-way valve for a fuel supply device according to claim 3, wherein the communication hole is provided on an outlet side of the main passage. The three-way valve for a fuel supply apparatus according to any one of claims 1 to 4, further comprising a holding member that is provided on a circumferential portion of the bimetal and holds the bimetal. 6. The three-way valve for a fuel supply apparatus according to claim 5, wherein the holding member is a pair of O-rings that sandwich the bimetal from both sides. 6. The three-way valve for a fuel supply device according to claim 5, wherein the holding member is a rubber ring member having a notch for sandwiching the bimetal from both sides. The three-way valve for a fuel supply apparatus according to any one of claims 1 to 7, further comprising a rubber seal material on a contact surface between the bimetal and the opening end of the bypass passage.