JP2008138518A - Fuel supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel supply device capable of exhibiting excellent durability while maintaining a conventional function. <P>SOLUTION: A housing 20 is fixed on a fuel tank 12 so that a motor mechanism 38 is positioned above the fuel tank 12. A suction pipe 28 communicating a suction port 24e and a liquid phase part in the fuel tank 12 is adopted as the housing 20. A delivery chamber 32 communicating with a delivery port 22c and surrounding a motor chamber 30 is formed in the housing 20. The motor mechanism 38 is not immersed in fuel 10 in the fuel tank 12, and copper such as a winding of the motor mechanism 38 in the fuel pump 14 is not corroded. Further, the suction pipe 28 is adopted, and the suction port 24e is communicated with the liquid phase part, and the motor mechanism 38 generating heat can be cooled by the fuel 10 in the delivery chamber 32. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel supply apparatus.

  Patent Document 1 discloses a conventional fuel supply device. This fuel supply device includes a fuel tank that stores fuel, and a fuel pump that is provided on the inner bottom surface of the fuel tank and that pumps fuel. Dimethyl ether (DME) is disclosed as a fuel.

  The fuel pump includes a housing, a drive shaft that is rotatably supported by the housing, a motor mechanism that rotationally drives the drive shaft, and a pump mechanism that performs a fuel pumping action by rotationally driving the drive shaft.

  The housing includes a motor chamber, a pump chamber that communicates with the motor chamber in the upper and lower axial directions below the motor chamber, a suction port that communicates with a suction region of the pump chamber, and a discharge port that communicates with a discharge region of the pump chamber. Is formed. Since the fuel pump is provided on the inner bottom surface of the fuel tank, the suction port communicates with the liquid phase portion in the fuel tank, and the discharge port communicates with the supply path downstream from the bottom surface of the fuel pump. . The drive shaft extends across the motor chamber and the pump chamber. The motor mechanism is disposed in the motor chamber, and the pump mechanism is disposed in the pump chamber.

  The supply path on the downstream side of the fuel pump is provided with an on-off valve that restricts the supply of fuel further downstream. A fuel supply device such as a fuel injection device may be provided further downstream of the supply path.

  In the conventional fuel supply apparatus configured as described above, in the fuel pump, the pump mechanism operates when the motor mechanism rotates the drive shaft. Thereby, the fuel in the liquid phase portion in the fuel tank is sucked into the suction area of the pump chamber from the suction port, and is pumped from the discharge area to the supply path through the discharge port. The fuel pressure-fed to the supply path is supplied to the fuel supply device through an on-off valve.

  In addition, this fuel supply device has a fuel pump provided on the inner bottom surface of the fuel tank, so that the heat generating motor mechanism is made of fuel in the liquid phase portion while facilitating communication between the suction port and the liquid phase portion. It is also cooling.

JP 2003-83188 A

  This invention makes it the subject which should be solved to provide the fuel supply apparatus which can exhibit the outstanding durability, maintaining the conventional function.

  The inventors have intensively studied to solve the above problems, and have clarified the factors that can further improve the durability of the fuel supply device as follows.

  First, dimethyl ether is adopted as a fuel together with an additive for lubrication, and carboxylic acid or the like exists in the additive. Additives such as carboxylic acids react with copper and corrode copper by being in contact with copper at a high concentration for a long time.

  On the other hand, in the fuel supply device, the fuel pump is provided on the inner bottom surface of the fuel tank, and the fuel pump is immersed in the fuel for a long time. The fuel pump includes a motor mechanism, and the motor mechanism inevitably has a portion using copper, such as a winding wire and a soldering portion. In the structure in which the fuel pump is provided on the inner bottom surface of the fuel tank, it is difficult to prevent the fuel from entering the motor chamber through the housing or the like.

  In other words, if the motor mechanism of the fuel pump can be prevented from being immersed in the fuel for a long time, copper such as the winding of the motor mechanism in the fuel pump can be prevented from corroding, and more excellent durability can be exhibited. can do. The inventors have completed the present invention described below based on the elucidation of such factors.

The fuel supply apparatus of the present invention includes a fuel tank that stores fuel containing dimethyl ether and an additive that reacts with copper,
A fuel pump provided in the fuel tank and pumping the fuel;

The fuel pump includes a motor chamber, a pump chamber communicating with the motor chamber, a suction port communicating with the suction region of the pump chamber, and a housing formed with a discharge port communicating with the discharge region of the pump chamber ,
A drive shaft extending across the motor chamber and the pump chamber and rotatably supported by the housing;
A motor mechanism that is disposed in the motor chamber and rotationally drives the drive shaft;
A pump mechanism disposed in the pump chamber and performing a pumping action of the fuel by rotational driving of the drive shaft;

The housing is fixed to the fuel tank such that the motor mechanism is located above the fuel tank;
The housing has a suction passage that communicates the suction port and a liquid phase portion in the fuel tank, and a discharge chamber that communicates with the discharge port and surrounds the motor chamber. It is characterized by.

  In the fuel supply device of the present invention, the motor mechanism is not immersed in the fuel, and the fuel can be almost completely prevented from entering the motor chamber by the liquid pressure of the fuel in the fuel tank. Copper such as mechanism windings will not corrode.

  Further, in this fuel supply device, the suction port and the liquid phase portion are communicated with each other by forming a suction passage in the housing that connects the suction port and the liquid phase portion in the fuel tank. Furthermore, since the discharge chamber surrounding the motor chamber is formed in the housing and this discharge chamber is communicated with the discharge port, the motor mechanism that generates heat can be cooled by the fuel in the discharge chamber.

  Therefore, the fuel supply device of the present invention can exhibit more excellent durability while maintaining the conventional function.

  The fuel pump housing is preferably formed with a return passage communicating the motor chamber to the gas phase portion in the fuel tank. In the fuel supply device of the present invention, the drive shaft is driven to rotate by the motor mechanism and the pump mechanism is operated by the drive shaft. Therefore, the motor chamber and the pump chamber communicate with each other although the motor chamber is above. For this reason, fuel in the pump chamber may enter the motor chamber due to high pressure in the discharge region, vibration acting on the fuel supply device, and the like. The fuel that has entered in this way is returned to the gas phase portion of the fuel tank through the return passage. For this reason, in this case, corrosion of the winding of the motor mechanism and the like can be more reliably prevented.

  The return passage is preferably provided with a check valve for preventing the backflow of fuel from the gas phase portion to the motor chamber. For example, when the fuel supply device is mounted on a vehicle, vibrations act on the fuel supply device, and the fuel in the fuel tank may flow back to the motor chamber via the gas phase portion and the return passage. This fuel is prevented from flowing back by a check valve provided in the return passage. For this reason, also in this case, corrosion of the winding of the motor mechanism and the like can be more reliably prevented.

  It is preferable that the motor chamber and the pump chamber are sealed with a seal member. As described above, the motor chamber and the pump chamber communicate with each other. However, if these are sealed by the seal member, it is possible to effectively prevent the fuel in the pump chamber from entering the motor chamber. . For this reason, also in this case, corrosion of the winding of the motor mechanism and the like can be more reliably prevented.

  An on-off valve that restricts the supply of fuel further downstream can be provided in the supply path on the downstream side of the discharge chamber. This is because the supply of fuel is restricted by closing the on-off valve in accordance with the operating status of the fuel supply apparatus. In this case, it is preferable that a check valve for preventing the backflow of fuel from the pump chamber to the liquid phase portion is provided in the suction passage. If the on-off valve is opened without pumping fuel, the fuel filled in the supply path, discharge chamber, pump chamber, suction port and suction passage will flow back to the liquid phase of the fuel tank. At the time of pumping, it takes a long time to supply the fuel to the fuel supply device. If the check valve prevents the fuel from flowing back to the liquid phase part, the fuel in the suction passage is supplied to the supply path in preference to the fuel in the fuel tank at the time of refeeding. Can be supplied immediately.

  The housing has a suction pipe extending downward from the suction port at the upper end and a bottom surface whose height is higher than the lowest liquid level in the liquid phase portion, covers the suction pipe in a container shape, and is normally closed by a check valve. And a suction tank having a mouth penetrating the bottom surface. In this case, when the on-off valve is opened without pumping fuel, the check valve closes the suction port on the bottom of the suction tank, so the supply path, discharge port, pump chamber, suction port upstream from the on-off valve The fuel filled in the port and the intake passage is stored in the intake tank. During re-pressure feeding, the fuel in the suction tank is sucked into the suction port through the suction pipe in preference to the fuel in the fuel tank. At this time, since the bottom surface of the suction tank is higher than the lowest liquid level of the fuel tank, the fuel can be reliably and quickly supplied to the fuel supply apparatus. When the fuel is continuously pumped, the check valve opens the suction port by a pump action, so that the fuel in the fuel tank is normally sucked into the suction port through the suction port and the suction pipe of the suction tank.

  It is preferable that the inside of the suction tank communicates with the gas phase portion through a vent passage. This is because, when the fuel returning to the suction tank exceeds the capacity of the suction tank, the fuel is returned to the liquid phase part through the gas phase part through the extraction passage.

  The pump chamber can communicate with the motor chamber in the upper and lower axial directions below the motor chamber. In this case, the pump mechanism is disposed in the pump chamber and can rotate integrally with the drive shaft, a driven shaft extending across the pump chamber, and disposed in the pump chamber and rotatable integrally with the driven shaft. It can consist of a driven gear. This gear pump mechanism is a positive displacement type and produces the above-described effects. If the pump mechanism is a gear pump mechanism, since the shaft length of the gear pump mechanism itself is short, the portion protruding above the fuel tank can be reduced. In the fuel supply apparatus of the present invention, a piston pump mechanism, a scroll pump mechanism, and other general ones can be employed as the pump mechanism.

  Hereinafter, Embodiments 1 to 5 embodying the present invention will be described with reference to the drawings.

  The fuel supply device according to the first embodiment is applied to a power engine for a vehicle. As shown in FIG. 1, the fuel supply device includes a fuel tank 12 that stores fuel 10, and a fuel pump 14 that is provided on the upper surface of the fuel tank 12 and pumps the fuel 10. As the fuel 10, a fuel containing dimethyl ether and an additive such as carboxylic acid for lubrication is employed. The inside of the fuel tank 12 is divided into a liquid phase portion made of the fuel 10 and a gas phase portion.

  The fuel pump 14 includes a housing including a motor case 20, a center block 22, an underblock 24, a mounting ring 26, and a suction pipe 28.

  In the motor case 20, a motor chamber 30 that forms a substantially cylindrical space at the top and bottom is formed with the center block 22, and an annular discharge chamber 32 that surrounds the motor chamber 30 is formed with the center block 22. A mounting flange 20a protrudes from the outer periphery of the motor case 20, and a bolt hole 20b penetrating vertically is formed in the mounting flange 20a.

  A center block 22 is provided at the lower end of the motor case 20. The center block 22 is provided with a main shaft hole 22a extending in the upper and lower axial directions, and a sub shaft hole 22b is recessed upward from the lower surface in parallel with the main shaft hole 22a.

  Further, the center block 22 is provided with a discharge port 22c which is opened between a main shaft hole 22a and a sub shaft hole 22b from the discharge region of a pump chamber 24p described later to the lower surface. The discharge port 22 c communicates with the discharge chamber 32 by a discharge passage 22 d penetrating the center block 22.

  Further, a return passage 22 f extending from the motor chamber 30 to the outer peripheral surface is formed in the center block 22. A mounting flange 22g protrudes from the outer periphery of the center block 22, and a bolt hole 22h penetrating vertically is also formed in the mounting flange 22g. The motor case 20 and the center block 22 are integrated by a bolt 34 inserted through the bolt holes 20b and 22h with an appropriate number of O-rings provided between them.

  An under block 24 is provided at the lower end of the center block 22. The under block 24 has a drive gear chamber 24a and a main shaft hole 24b coaxially formed with the main shaft hole 22a and recessed downward from the upper surface, and a driven gear chamber 24c and a sub shaft hole 24d coaxial with the sub shaft hole 22b. Is recessed downward from the upper surface. The drive gear chamber 24a and the driven gear chamber 24c are the pump chamber 24p.

  The under block 24 is provided with a suction port 24e that opens from the suction region of the pump chamber 24p to the lower surface between the main shaft hole 24b and the sub shaft hole 24d. The under block 24 is integrated with the center block 22 by a bolt (not shown) with an O-ring provided between the under block 24 and the center block 22.

  The attachment ring 26 has a recess 26 a that fits into the fuel tank 12, and a female screw 26 b that screws the bolt 34. The motor case 20 and the center block 22 are fixed to the upper surface of the fuel tank 12 by bolts 34 fastened to the female thread 26b of the mounting ring 26. An O-ring is also interposed between the mounting ring 26 and the center block 22. The mounting ring 26 is also provided with a recess 26 c that communicates the return passage 22 f with the gas phase portion of the fuel tank 12.

  The suction pipe 28 has a tubular shape extending in the axial direction, and the inside of the suction pipe 28 serves as a suction passage. The suction pipe 28 is fitted into the suction port 24 e of the underblock 24, extends downward, and is immersed in the fuel 10 at the lower end. A filter 50 made of a metal mesh covering the suction pipe 28 is provided on the lower surface of the underblock 24.

  A drive shaft 36 extends vertically so as to straddle the motor chamber 30, the drive gear chamber 24a, and the main shaft holes 22a, 24b. The drive shaft 36 is supported by the motor case 20, the center block 22, and the under block 24. A shaft is rotatably supported via the device.

  A motor mechanism 38 that integrally includes a drive shaft 36 and inevitably has a portion using copper, such as a winding and a soldering portion, is disposed in the motor chamber 30 so as to be positioned above the fuel tank 12. Yes. Here, “above the fuel tank 12” means that the motor mechanism 38 exists above the liquid surface where the liquid phase portion of the fuel tank 12 is the highest. In the present embodiment, the motor mechanism 38 is located above the upper surface of the fuel tank 12.

  A drive gear 40 is disposed in the drive gear chamber 24a so that the drive shaft 36 is inserted therethrough and can rotate integrally with the drive shaft 36. A driven shaft 42 extends vertically so as to straddle the driven gear chamber 24c and the auxiliary shaft holes 22b and 24d, and the driven shaft 42 can be rotated on the center block 22 and the under block 24 via a bearing device. It is pivotally supported. A driven gear 44 is provided in the driven gear chamber 24c. The driven gear 44 is inserted through the driven shaft 42 and can rotate integrally with the driven shaft 42. Thus, the gear pump mechanism 52 is disposed in the pump chamber 24p.

  The discharge chamber 32 communicates with the supply path 46 on the downstream side from the side surface of the motor case 20, and the supply path 46 is provided with an opening / closing valve 48 that restricts the supply of fuel further downstream. A fuel injection device is provided further downstream of the supply path 46.

  Since the fuel supply device configured as described above employs the gear pump mechanism 52 having a short shaft length, even if the fuel pump 14 is provided on the upper surface of the fuel tank 12, the portion protruding above the fuel tank 12 To make it easier to install in vehicles.

  In the fuel pump 14, the gear pump mechanism 52 is activated by the motor mechanism 38 rotating the drive shaft 36. As a result, the liquid phase fuel 10 in the fuel tank 12 is sucked into the suction area of the pump chamber 24p from the suction pipe 28 via the suction port 24e, and from the discharge area to the discharge port 22c, the discharge passage 22d, and the discharge chamber 32. Then, it is pumped to the supply path 46. The fuel 10 pumped to the supply path 46 is supplied to the fuel injection device via the on-off valve 48.

  In the meantime, in this fuel supply device, since the motor mechanism 38 is located above the fuel tank 12, the motor mechanism 38 is not immersed in the fuel 10, and the fuel 10 is caused by the hydraulic pressure of the fuel 10 in the fuel tank 12. Since it can be almost completely prevented from entering the motor chamber 30, copper such as windings of the motor mechanism 38 in the fuel pump 14 is not corroded.

  Further, in this fuel supply device, the suction port 24 e and the liquid phase portion in the fuel tank 12 are communicated with each other through a suction passage in the suction pipe 28. Further, since the discharge chamber 32 surrounding the motor chamber 30 is formed in the motor case 20 and this discharge chamber 32 is connected to the discharge port 22c, the motor mechanism 38 that generates heat is cooled by the fuel 10 in the discharge chamber 32. You can also.

  Therefore, this fuel supply apparatus can exhibit more excellent durability while maintaining the conventional function.

  Further, in this fuel supply device, the fuel 10 in the pump chamber 24p may enter the motor chamber 30 through the bearing device in the main shaft hole 22a due to high pressure, vibration, etc. in the discharge region. However, since this fuel supply device has the return passage 22f that communicates the motor chamber 30 with the gas phase portion, the fuel 10 that has entered the motor chamber 30 in this way is returned to the gas phase portion of the fuel tank 12 by the return passage 22f. Refluxed. For this reason, the windings of the motor mechanism 38 are not immersed in the fuel 10 for a long time, and corrosion of the windings of the motor mechanism 38 is more reliably prevented.

  Furthermore, since this fuel supply apparatus employs the filter 50, even if foreign matter is mixed in the fuel 10 stored in the fuel pump 12, the foreign matter is prevented from entering the pump chamber 24p. Can do. This prevents abnormal operation of the fuel pump 14 and the fuel injection device.

  As shown in FIGS. 2 and 3, the fuel supply device of the second embodiment is provided with a check valve 22i in the return passage 22f of the fuel supply device of the first embodiment, and a gas phase portion of the fuel tank 12 is formed by the check valve 22i. Thus, the backflow of the fuel 10 from the motor to the motor chamber 30 is prevented. The check valve 22i includes a valve body 22l and a pressing spring 22k that urges the valve body 22l in the closing direction. Other configurations are the same as those of the first embodiment.

  When this fuel supply device is mounted on a vehicle, for example, vibrations act on the fuel supply device, and even if the fuel 10 in the fuel tank 12 tries to flow back to the motor chamber 30 via the gas phase portion and the return passage 22f, the fuel is supplied. 10 is prevented from backflow by a check valve 22i. For this reason, also in this case, corrosion of the winding of the motor mechanism 38 and the like can be more reliably prevented. Other functions and effects are the same as those of the first embodiment.

  As shown in FIG. 4, the fuel supply device of the third embodiment is provided with a lip seal 22j as a seal member in the main shaft hole 22a in the fuel supply device of the first embodiment, and the motor chamber 30 and the pump chamber are provided by the lip seal 22j. 24p is sealed. Other configurations are the same as those of the first embodiment.

  In this fuel supply apparatus, it is possible to effectively prevent the fuel 10 in the pump chamber 24p from entering the motor chamber 30. For this reason, also in this case, corrosion of the winding of the motor mechanism 38 and the like can be more reliably prevented. Other functions and effects are the same as those of the first embodiment.

  As shown in FIG. 5, the fuel supply device of the fourth embodiment employs another suction pipe 54 instead of the suction pipe 28 in the fuel supply device of the third embodiment.

  A spring chamber 54 a having a large inner diameter is formed at the lower end of the suction pipe 54. The inside of the suction pipe 54 is a suction passage, and the suction passage can store the fuel 10 upstream of the on-off valve 48.

  The spring chamber 54a communicates with the liquid phase portion through a lower end through hole 54b. In the spring chamber 54a, a pressing spring 56a having an urging force in the axial direction is housed, and a valve body 56b capable of closing the through hole 54b from the inside by the pressing spring 56a is provided. The pressing spring 56a and the valve body 56b constitute a check valve 56 that prevents the backflow of the fuel 10 from the pump chamber 24p to the liquid phase portion. Other configurations are the same as those of the third embodiment.

  In this fuel supply apparatus, when the on-off valve 48 is opened without pumping the fuel 10, the check valve 56 closes the through hole 54 b of the suction pipe 54, so that the supply path 46 upstream from the on-off valve 48. The discharge chamber 32, the discharge passage 22d, the pump chamber 24p, the suction port 22c, and the fuel 10 filled in the suction passage are blocked by the check valve 56 at the lower end of the suction pipe 54 and stored in the fuel pump 14. The

  For this reason, at the time of re-pressure feeding, the fuel 10 in the fuel pump 14 is supplied to the supply path 46 in preference to the fuel 10 in the fuel tank 12, so that the fuel 10 can be immediately supplied to the fuel injection device. At the time of re-pressure feeding, the fuel 10 in the suction pipe 54 pulls up the pressing spring 54b by the pump action, and the through hole 54b is opened. Other functions and effects are the same as those of the third embodiment.

  As shown in FIG. 6, the fuel supply device of the fifth embodiment employs another suction pipe 56 instead of the suction pipe 28 in the fuel supply device of the third embodiment, and employs a suction tank 58 instead of the filter 50. It is a thing.

  A flange 56 a is formed at the lower part of the outer peripheral surface of the suction pipe 56. Further, on the outer peripheral surface of the suction pipe 56, a through hole 56c different from the lower end through hole 56b is formed at a lower part of the flange 56a.

  The suction tank 58 covers the suction pipe 56 in a container shape. The bottom surface of the suction tank 58 is set higher than the lowest liquid level of the liquid phase portion of the fuel tank 12. Further, a suction port 58a communicating with the liquid phase portion is formed at the bottom surface of the suction tank 58 even at the lowest liquid level. The intake tank 58 can store the fuel 10 upstream of the on-off valve 48.

  Around the suction pipe 56, a pressing spring 60a having a flange 56a as a seating surface and having an urging force in the axial direction is provided. A valve body 60b is provided at the lower end of the suction pipe 56. The valve body 60b can close the suction port 58a from the inside of the suction tank 58 by a pressing spring 60a. The pressing spring 60a and the valve body 60b constitute a check valve 60 that prevents the backflow of the fuel 10 from the pump chamber 24p to the liquid phase portion.

  The underblock 24 is formed with a removal passage 24f. The extraction passage 24 f communicates with the return passage 22 f formed in the center block 22 from the lower surface of the underblock 24, and communicates the upper end of the suction tank 58 with the gas phase portion of the fuel tank 12. Other configurations are the same as those of the first embodiment.

  In this fuel supply device, when the opening / closing valve 48 is opened without pumping the fuel 10, the check valve 60 closes the suction port 58 a on the bottom surface of the suction tank 58. The fuel 10 filled in the passage 46, the discharge chamber 32, the discharge passage 22d, the discharge port 22c, the pump chamber 24p, the suction port 24e, and the suction pipe 56 is stored in the suction tank 58.

  At this time, the suction tank 58 can store all the fuel 10 upstream of the on-off valve 48. Further, when the fuel 10 on the downstream side of the on-off valve 48 is recirculated by rotating the motor mechanism 38 in the reverse direction without closing the on-off valve 48, the fuel 10 exceeding the capacity of the suction tank 58 is discharged. It returns to the fuel tank 12 through the extraction passage 24f and the return passage.

  During re-pressure feeding, the fuel 10 in the suction tank 58 is sucked into the suction port 24e through the suction pipe 56 in preference to the fuel 10 in the fuel tank 12. At this time, since the bottom surface of the suction tank 58 is lower than the lowest liquid level of the fuel tank 12, the fuel 10 can be reliably and quickly supplied to the fuel injection device. When the fuel 10 is continuously pumped, the check valve 60 opens the suction port 58a by the pump action, so that the fuel 10 in the fuel tank 12 normally enters the suction port 58a of the suction tank 58 and the suction pipe 56. The air is sucked into the suction port 24e through the through holes 56b and 56c. When the valve body 60a is seated in the through hole 56b, the fuel 10 is sucked into the suction pipe 56 from the through hole 56c. Other functions and effects are the same as those of the first embodiment.

  In the above, the present invention has been described with reference to the first to fifth embodiments. However, the present invention is not limited to the first to fifth embodiments, and can be appropriately modified and applied without departing from the spirit of the present invention. Needless to say.

  The present invention is applicable to a fuel supply device for supplying fuel to a power engine for a vehicle.

It is sectional drawing of the fuel supply apparatus of Example 1. FIG. It is sectional drawing of the fuel supply apparatus of Example 2. FIG. It is a partial expanded sectional view of the fuel supply apparatus of Example 2. FIG. FIG. 6 is a cross-sectional view of a fuel supply device according to a third embodiment. It is sectional drawing of the fuel supply apparatus of Example 4. It is sectional drawing of the fuel supply apparatus of Example 5. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Fuel 12 ... Fuel tank 14 ... Fuel pump 30 ... Motor chamber 24p ... Pump chamber 24e ... Suction port 22c ... Discharge port 20, 22, 24, 26 ... Housing (20 ... Motor case, 22 ... Center block, 24 ... Under Block, 26 ... mounting ring)
36 ... Drive shaft 38 ... Motor mechanism 52 ... Pump mechanism 28, 54, 56 ... Suction pipe (suction passage)
32 ... Discharge chamber 22f ... Return passage 22i ... Check valve 22j ... Lip seal (seal member)
DESCRIPTION OF SYMBOLS 50 ... Filter 46 ... Supply path 48 ... On-off valve 56, 60 ... Check valve 58a ... Suction port 58 ... Suction tank 24f ... Extraction passage 24b ... Drive gear 42 ... Drive shaft 44 ... Drive gear

Claims (8)

A fuel tank for storing fuel containing dimethyl ether and an additive that reacts with copper;
A fuel pump provided in the fuel tank and pumping the fuel;
The fuel pump includes a motor chamber, a pump chamber communicating with the motor chamber, a suction port communicating with the suction region of the pump chamber, and a housing formed with a discharge port communicating with the discharge region of the pump chamber ,
A drive shaft extending across the motor chamber and the pump chamber and rotatably supported by the housing;
A motor mechanism that is disposed in the motor chamber and rotationally drives the drive shaft;
A pump mechanism disposed in the pump chamber and performing a pumping action of the fuel by rotational driving of the drive shaft;
The housing is fixed to the fuel tank such that the motor mechanism is located above the fuel tank;
The housing has a suction passage that communicates the suction port and a liquid phase portion in the fuel tank, and a discharge chamber that communicates with the discharge port and surrounds the motor chamber. A fuel supply device.   2. The fuel supply device according to claim 1, wherein a return passage is formed in the housing for communicating the motor chamber with a gas phase portion in the fuel tank.   The fuel supply device according to claim 2, wherein the return passage is provided with a check valve that prevents a back flow of the fuel from the gas phase portion to the motor chamber.   The fuel supply device according to claim 1, wherein the motor chamber and the pump chamber are sealed by a sealing member.   The supply passage on the downstream side of the discharge chamber is provided with an on-off valve that restricts the supply of the fuel further downstream, and the suction passage prevents the fuel from flowing backward from the pump chamber to the liquid phase portion. The fuel supply apparatus according to claim 1, wherein a check valve for preventing the fuel supply is provided.   The housing has a suction pipe extending downward from the suction port at the upper end and a bottom surface having a height higher than the lowest liquid level of the liquid phase portion, covers the suction pipe in a container shape, and is normally operated by the check valve. The fuel supply device according to claim 5, wherein the suction port closed at the bottom has a suction tank penetrating through the bottom surface.   The fuel supply device according to claim 6, wherein the inside of the suction tank communicates with the gas phase portion by a vent passage. The pump chamber communicates with the motor chamber in the upper and lower axial directions below the motor chamber,
The pump mechanism is disposed in the pump chamber and is rotatable integrally with the drive shaft, a driven shaft extending across the pump chamber, a pump shaft disposed in the pump chamber, and the driven shaft. The fuel supply device according to claim 1, comprising a driven gear that can rotate integrally.

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