JP2014234774A - Diesel fuel supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a diesel fuel supply device capable of simplifying a constitution to prevent insufficient fuel supply at a low temperature.SOLUTION: A bypass valve device 1 includes a temperature sensitive valve element 20 displacing by detecting a temperature of supply fuel in a bypass passage 80, and sitting on or separating from a valve seat 81 in accompany with the displacement to open and close the bypass passage 80. Further it includes a pressure-sensitive valve element 30 displacing by detecting pressure difference between an upstream portion 61 and a downstream portion 62 with respect to a fuel filter 9a of a fuel passage 60, and sitting on or separating from a valve seat 82 in accompany with the displacement to open and close the bypass passage 80.

Description

  The present invention relates to a diesel fuel supply apparatus that filters fuel supplied from a fuel tank to a supply destination with a fuel filter.

  2. Description of the Related Art Conventionally, in addition to a normal fuel passage for supplying fuel from a fuel tank to a fuel injection pump through a fuel filter, a diesel fuel supply apparatus having a bypass passage for connecting the fuel tank and the fuel injection pump via an electromagnetic valve has been provided. Are known. In this fuel supply device, the electronic control unit (ECU) opens the electromagnetic valve for a predetermined time immediately after the engine is started to supply fuel via the bypass passage. As a result, even if the fuel filter is clogged with wax precipitated in the fuel at the time of low temperature start, engine startability is ensured (for example, see Patent Document 1 below).

JP-A-5-215029

  However, the above-described conventional diesel fuel supply device requires a solenoid valve and an electronic control device that controls the opening / closing operation of the solenoid valve for the purpose of preventing a shortage of fuel supply at low temperatures. There's a problem.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a diesel fuel supply device capable of simplifying a configuration for preventing a shortage of fuel supply at low temperatures.

In order to achieve the above object, in the present invention,
A valve seat (81) formed to face the bypass passage;
A temperature sensing valve body (20) that senses and displaces the temperature of the supplied fuel in the bypass passage, and opens and closes the bypass passage by being attached to and detached from the valve seat in accordance with the displacement;
The temperature sensing valve element is characterized in that it is separated from the valve seat when the temperature of the fuel supplied in the bypass passage falls below a predetermined temperature.

  According to this, the temperature sensing valve body is separated from the valve seat to open the bypass passage when the temperature of the supplied fuel in the bypass passage becomes lower than a predetermined temperature, and the supply destination from the fuel tank without passing through the fuel filter. To supply fuel. Therefore, even if the fuel filter is clogged with the wax precipitated in the fuel at a low temperature, the fuel can be supplied to the supply destination through the bypass passage. Thus, by using the temperature sensing valve body, it is possible to prevent insufficient fuel supply at low temperatures without using an electromagnetic valve, an electronic control device, or the like. In this way, it is possible to simplify the configuration for preventing fuel supply shortage at low temperatures.

  In addition, the code | symbol in the parenthesis attached | subjected to each said means is an example which shows a corresponding relationship with the specific means as described in embodiment mentioned later.

It is a schematic block diagram of the diesel fuel supply apparatus in 1st Embodiment to which this invention is applied. It is sectional drawing which shows schematic structure of the bypass valve apparatus (bypass passage on-off valve device) used for a diesel fuel supply apparatus, and has shown the state which closed the bypass passage. It is sectional drawing which shows the state which the bypass valve apparatus opened the bypass channel. Only the pressure sensitive valve body (differential pressure sensing valve body) of the bypass valve device is opened, and the bypass passage is closed.

  A plurality of modes for carrying out the present invention will be described below with reference to the drawings. In each embodiment, parts corresponding to the matters described in the preceding embodiment may be denoted by the same reference numerals, and redundant description may be omitted. In the case where only a part of the configuration is described in each embodiment, the other parts of the configuration are the same as those described previously. In addition to the combination of parts specifically described in each embodiment, the embodiments may be partially combined as long as the combination is not particularly troublesome.

(First embodiment)
A first embodiment to which the present invention is applied will be described with reference to FIGS.

  As shown in FIG. 1, the diesel fuel supply apparatus of this embodiment is a common rail type fuel injection system mounted on a vehicle, for example. The diesel fuel supply device includes a fuel tank 2, a supply pump 3, a common rail 4, an injector 5, and a fuel filter device 9 interposed between the fuel tank 2 and the supply pump 3.

  The supply pump 3 is configured by a feed pump (low pressure feed pump), a solenoid valve as a flow rate control device, a high pressure pump, and the like, although a specific configuration is not shown. As the feed pump, for example, a trochoid pump or a vane pump can be used. For example, a plunger pump can be used as the high-pressure pump.

  When the supply pump 3 is operated, the normal pressure fuel stored in the fuel tank 2 is sucked, flows through the fuel pipe 6 and is supplied into the common rail 4. At that time, water is separated from the fuel in the fuel filter device 9 and foreign matters in the fuel are captured.

  The common rail 4 holds the fuel pressurized by the high-pressure pump of the supply pump 3 in an accumulated state. An injector 5 that injects fuel into each cylinder of the engine is connected to the common rail 4 according to the number of cylinders. The fuel held in the pressure accumulation state in the common rail 4 is injected from the injector 5. A return pipe 7 is connected to the common rail 4. The surplus fuel in the common rail 4 is returned to the fuel tank 2 via the return pipe 7.

  Low-pressure fuel that flows into the control pressure chamber of each injector 5 and is discharged from the injector 5 low-pressure port such as fuel and leak fuel used for injector operation, and low-pressure fuel such as leak fuel from the supply pump 3 also recirculate. It joins the pipe 7 and returns to the fuel tank 2.

  Further, the common rail fuel injection system of the present embodiment is connected to an ECU (not shown) as a control means. This ECU optimally controls the flow rate of the fuel discharged from the supply pump 3 based on the input fuel pressure inside the common rail 4, the engine speed Ne, the accelerator opening α, and the like. Further, the ECU controls the opening / closing timing of the solenoid valve of the injector 5 connected to the common rail 4. Thus, the fuel injection timing and the fuel injection amount into each cylinder of the engine are controlled.

  A bypass pipe 8 is connected to the fuel pipe 6 so as to bypass the fuel filter device 9. The upstream end of the bypass pipe 8 is connected to the fuel pipe 6 at a portion on the fuel flow upstream side of the fuel filter (filter body) 9 a of the fuel filter device 9. The downstream end of the bypass pipe 8 is connected to the fuel pipe 6 at a portion on the downstream side of the fuel flow with respect to the fuel filter 9a. The fuel filter 9a can be constituted by a honeycomb-like filter made of, for example, a pulp material. The bypass pipe 8 is provided with a bypass valve device 1 that is a bypass passage opening / closing valve device.

  The supply pump 3, the common rail 4, and the injector 5 correspond to a supply destination to which the fuel supplied from the fuel tank 2 is supplied via the fuel pipe 6 and the bypass pipe 8.

  As shown in FIG. 2, the fuel passage 60 formed in the fuel pipe 6 and in the bypass valve device 1 includes an upstream portion 61 that is an upstream side portion (upstream side portion) of the fuel filter 9a, and the fuel filter 9a. It consists of the downstream part 62 which is a downstream part (downstream part) rather than. The bypass passage 80 formed in the bypass pipe 8 and the bypass valve device 1 connects the upstream portion 61 and the downstream portion 62 of the fuel passage 60 by bypassing the fuel filter 9a.

  The bypass valve device 1 includes a housing 10, a temperature sensing valve body 20 (corresponding to a temperature sensing valve body), a pressure sensing valve body 30 (corresponding to a differential pressure sensing valve body), and a spring 40. The housing 10 is made of a metal such as an aluminum alloy or a resin, for example, and is configured by combining the upper housing 11, the middle housing 12, and the lower housing 13. The upper housing 11 and the middle housing 12 are joined to each other, for example, by screwing. The middle housing 12 and the lower housing 13 are joined to each other by screwing, for example. The housing 10 is composed of three members, but is not limited to this.

  Although not shown, for example, O-rings, which are seal members, are interposed between the upper housing 11 and the middle housing 12 and between the middle housing 12 and the lower housing 13. These O-rings form a seal structure in which the fuel passage 60 and the bypass passage 80 in the housing 10 are isolated from the external space.

  The upper housing 11 is formed with an introduction passage 83 extending from the left end face in the drawing to the right in the drawing. An upstream side portion of the bypass pipe 8 is connected to the introduction port at the left end of the introduction passage 83 in the figure. In the upper housing 11, an annular passage 84 having an annular cross section extending in the vertical direction in the figure and a central passage 85 having a circular section extending in the vertical direction in the figure inside the annular passage 84 are formed.

  The upper housing 11 has an annular wall 111 located between the annular passage 84 and the central passage 85. The lower end of the annular wall 111 functions as a stopper when the temperature-sensitive valve body 20 is maximum displaced upward in the figure, and restricts excessive displacement of the temperature-sensitive valve body 20. By providing the central passage 85 inward of the annular passage 84, the fuel contact area of the temperature sensitive valve body 20 can be reliably ensured even when the temperature sensitive valve body 20 is displaced to the maximum in the figure.

  The annular passage 84 and the central passage 85 communicate with the introduction passage 83 at the upper upstream end in the figure. Downstream downstream ends of the annular passage 84 and the central passage 85 are communicated with a valve chamber 86 in which the temperature sensitive valve body 20 is disposed. The valve chamber 86 is formed by disposing concave portions having a circular cross section formed in the upper housing 11 and the middle housing 12 so as to face each other.

  The temperature-sensitive valve body 20 is composed of, for example, a bimetal plate formed by stacking and integrating different metal layers. The temperature-sensitive valve body 20 is formed, for example, in a disc shape with a central portion having a curved structure, and a peripheral portion is sandwiched between the upper housing 11 and the middle housing 12 (for example, gently sandwiched). In the valve chamber 86, the space in the upper part of the drawing and the space in the lower part of the drawing with respect to the temperature sensing valve body 20 communicate with each other through a communication passage 87 formed so as to go around the side of the temperature sensing valve body 20.

  An annular convex portion standing from the bottom surface of the concave portion of the middle housing 12 is formed on the illustrated lower surface of the valve chamber 86. The upper end surface of the annular convex portion shown in the figure is an annular valve seat 81 (corresponding to a valve seat and a first valve seat) on which the temperature sensitive valve body 20 is seated. A fuel flow passage 88 is formed in the middle housing 12, with the inside of the valve seat 81 as a valve opening (inlet when opening). The illustrated lower end of the flow passage 88 communicates with a valve chamber 89 in which the pressure-sensitive valve body 30 is disposed.

  The valve chamber 89 is formed as a recess having a circular cross section that is recessed upward from the lower surface of the middle housing 12 in the figure. On the other hand, a back pressure chamber 63 is formed below the valve chamber 89 in the figure. The back pressure chamber 63 is formed as a recess having a circular cross section that is recessed downward from the upper surface of the lower housing 13 in the figure. The valve chamber 89 and the back pressure chamber 63 are disposed so as to face each other with the pressure sensitive valve body 30 interposed therebetween.

  The pressure-sensitive valve body 30 is made of, for example, metal, and the curved plate portion 31, the needle portion 32, and the protruding portion 33 are integrally formed. The curved plate portion 31 is formed in a disc shape with a central portion having a curved structure, and a peripheral portion is sandwiched between the middle housing 12 and the lower housing 13.

  The needle portion 32 protrudes upward in the drawing from the center of the upper surface of the curved plate portion 31 in the drawing. On the other hand, the protruding portion 33 protrudes downward from the center of the lower surface of the curved plate portion 31 in the drawing.

  In the middle housing 12, an annular hanging wall 121 projects downward from the center of the bottom surface of the concave portion of the valve chamber 89 (the upper surface of the concave portion in the drawing). An opening is formed in the central portion of the bottom surface of the concave portion of the valve chamber 89 in the region where the hanging wall 121 protrudes, and the peripheral edge of the opening is a valve seat 82 (corresponding to the second valve seat). When the pressure-sensitive valve body 30 is displaced, the needle portion 32 is displaced in the vertical direction in the figure inside the drooping wall 121, and the tip portion of the needle portion 32 is attached to and detached from the valve seat 82.

  In the middle housing 12, a fuel flow passage is formed with the inside of the valve seat 82 as a valve port (opening inlet), and the upper end of the flow passage in the figure communicates with the outlet passage 90. The lead-out passage 90 extends rightward in the drawing to the right end surface of the middle housing 12 in the drawing. A downstream portion of the bypass pipe 8 is connected to the outlet on the right end of the outlet passage 90 in the figure.

  The lower housing 13 is formed with a through-hole penetrating in the left-right direction in the figure, and this through-hole forms a part of the downstream portion 62 of the fuel passage 6. The back pressure chamber 63 communicates with the downstream portion 62 through the communication path 64. In the lower housing 13, a stopper 131 protrudes upward from the bottom of the recess of the back pressure chamber 63 in the figure. The stopper 131 protrudes from the peripheral edge of the upper opening of the communication path 64 in the figure. When the pressure-sensitive valve body 30 is maximum displaced downward in the drawing, for example, the stopper 131 comes into contact with the protrusion 33 to restrict excessive displacement of the pressure-sensitive valve body 30. A plurality of stoppers 131 are formed at intervals in the circumferential direction so that the continuous communication state between the downstream portion 62 and the back pressure chamber 63 is not hindered regardless of the displacement of the pressure-sensitive valve body 30.

  The valve chamber 89 is a pressure application chamber that applies the pressure of the supplied fuel in the bypass passage 80 to the upper surface of the curved plate portion 31 of the pressure-sensitive valve body 30. On the other hand, the back pressure chamber 63 is a back side pressure application chamber that applies the fuel pressure of the downstream portion 62 of the fuel passage 60 to the lower surface of the curved plate portion 31 of the pressure sensitive valve body 30.

  For example, a coiled spring 40 is contracted between the pressure-sensitive valve body 30 and the lower housing 13. The spring 40 constitutes a biasing means that always biases the pressure-sensitive valve body 30 upward in the drawing. The spring 40 is provided to stably reverse the curved plate portion 31 with a predetermined pressure difference.

  The illustrated upper end of the spring 40 is in contact with the illustrated lower surface of the curved plate portion 31. The illustrated upper end of the spring 40 is positioned in the radial direction by the projecting portion 33 positioned inward. The illustrated lower end of the spring 40 is in contact with the bottom surface of the recess of the back pressure chamber 63. The illustrated lower end of the spring 40 is positioned in the radial direction by a stopper 131 positioned inward.

  In the bypass valve device 1 described above, the introduction passage 83, the annular passage 84, the central passage 85, the valve chamber 86, the communication passage 87, the flow passage 88, the valve chamber 89 and the outlet passage 90 are parts of the bypass passage 80 in the housing 10. Is configured. The valve seat 81 and the valve seat 82 are formed in an annular shape so as to face the bypass passage 80. The valve seat 81 and the valve seat 82 are positioned in series with respect to the fuel flow in the bypass passage 80.

  The temperature sensing valve body 20 changes its curved state in accordance with the temperature of the supplied fuel in the bypass passage 80 (specifically, in the valve chamber 86), and the temperature sensing displacement valve body whose center portion is displaced in the vertical direction in the figure. It is. When the temperature of the supplied fuel is relatively high, the temperature sensitive valve body 20 is seated on the valve seat 81 as shown in FIG. When the temperature of the supplied fuel falls below a first predetermined temperature (for example, 20 ° C.), the temperature-sensitive valve body 20 is separated from the valve seat 81 and opens the valve port. On the other hand, when the temperature of the supplied fuel rises to a second predetermined temperature (for example, 40 ° C.) higher than the first predetermined temperature, the temperature-sensitive valve body 20 is seated on the valve seat 81 and closes the valve opening. .

  The temperature sensitive valve body 20 uses a bimetal plate and has a curved structure at the displacement portion, so that the valve opening temperature and the valve closing temperature are different depending on the heat capacity, the structural rigidity at the time of inversion, and the like. That is, the temperature-sensitive valve body 20 forms a hysteresis between the valve opening operation and the valve closing operation.

  The pressure sensing valve body 30 is a differential pressure sensing displacement valve body in which the bending state of the bending plate portion 31 changes according to the pressure difference between the valve chamber 89 and the back pressure chamber 63 and the needle portion 32 is displaced in the vertical direction in the figure. . When the difference between the pressure in the valve chamber 89 and the pressure in the back pressure chamber 63 is relatively low, the needle portion 32 is seated on the valve seat 82 as shown in FIG. When the pressure difference of the valve chamber 89 with respect to the back pressure chamber 63 rises to a first predetermined value or more, the curved state of the curved plate portion 31 is reversed, so that the needle portion 32 is separated from the valve seat 82 and opens the valve port. It has become. On the other hand, when the pressure difference of the valve chamber 89 with respect to the back pressure chamber 63 falls below a second predetermined value that is smaller than the first predetermined value, the needle portion 32 sits on the valve seat 82 and closes the valve port. .

  Since the pressure sensing valve body 30 has a curved structure at the displacement portion of the curved plate portion 31, the valve opening pressure difference and the valve closing pressure difference differ depending on the structural rigidity at the time of inversion. That is, the pressure-sensitive valve body 30 forms hysteresis in the valve opening operation and the valve closing operation.

  In the bypass valve device 1 having the above-described configuration, for example, when the outside air temperature is relatively low and the fuel temperature in the valve chamber 86 has dropped below the first predetermined temperature, the temperature sensing valve body 20 is as shown in FIG. The valve port is opened away from the valve seat 81. At this time, when the supply pump 3 is driven, the fuel flows through the fuel passage 60 and is filtered by the fuel filter 9 a of the fuel filter device 9. If the supplied fuel is at a relatively low temperature when the supply pump 3 is activated, the wax component in the fuel is deposited, the fuel filter 9a is clogged, and the pressure loss increases. When the supply pump 3 is activated, clogging may have already occurred due to the wax component precipitated from the fuel contained in the fuel filter 9a.

  When fuel flows through the fuel passage 60 in a state where the pressure loss of the fuel filter 9a is large, the pressure in the downstream portion 62 of the fuel passage 60 decreases more than the pressure in the upstream portion 61 (so-called negative pressure is generated). Accordingly, the pressure in the back pressure chamber 63 communicating with the downstream portion 62 communicates with the upstream portion 61 via the upstream portion 80a of the bypass passage 80 (the upstream portion of the bypass passage on the fuel flow upstream side of the valve seat 82). The pressure of the valve chamber 89 to be increased. When the pressure difference of the valve chamber 89 with respect to the back pressure chamber 63 becomes equal to or greater than the first predetermined value, the pressure-sensitive valve body 30 opens away from the valve seat 82 as shown in FIG.

  When the temperature-sensitive valve body 20 is separated from the valve seat 81 and the pressure-sensitive valve body 30 is separated from the valve seat 82, the bypass passage 80 is opened, and the supplied fuel can flow. A larger amount of fuel flows in the bypass passage 80 than in the fuel passage 60 where the pressure loss of the fuel filter 9a is large, and the supplied fuel is supplied to the supply destination such as the supply pump 3 without shortage.

  When the relatively high-temperature recirculated fuel returns from the supply destination such as the supply pump 3 to the fuel tank 2 via the recirculation pipe 7, the temperature of the fuel supplied through the fuel passage 60 and the bypass passage 80 rises. When the temperature of the supplied fuel rises and the fuel temperature in the valve chamber 86 rises to a second predetermined temperature or higher, the temperature sensitive valve body 20 is seated on the valve seat 81 and closes the bypass passage 80.

  Further, when the temperature of the supplied fuel rises, the wax component adhering to the fuel filter 9a is melted and clogging is eliminated. Accordingly, the pressure loss of the fuel filter 9a is reduced, and the pressure difference between the valve chamber 89 and the back pressure chamber 63 is reduced. When the pressure difference falls below the second predetermined value, the pressure-sensitive valve body 30 is seated on the valve seat 82 and closes the bypass passage 80. When either one of the valve bodies 20 and 30 is seated on the valve seat, the bypass passage 80 is closed and the supply fuel is supplied to the supply destination through the fuel passage 60.

  According to the configuration and operation described above, the bypass valve device 1 includes the valve seat 81 formed so as to face the bypass passage 80. The bypass valve device 1 includes a temperature-sensitive valve body 20 that senses and displaces the temperature of the fuel supplied in the bypass passage 80 and opens and closes the bypass passage 80 by being attached to and detached from the valve seat 81 in accordance with the displacement. The temperature-sensitive valve body 20 is separated from the valve seat 81 when the temperature of the supplied fuel in the bypass passage 80 decreases below the first predetermined temperature.

  Further, the bypass valve device 1 includes a valve seat 82 that is positioned in series with the valve seat 81 with respect to the bypass passage 80 and that faces the bypass passage 80. The bypass valve device 1 detects and displaces a pressure difference between the upstream portion 61 and the downstream portion 62 of the fuel passage 60 relative to the fuel filter 9a, and opens and closes the bypass passage 80 by being seated on the valve seat 82 in accordance with the displacement. A pressure sensitive valve body 30 is provided. The pressure-sensitive valve body 30 is separated from the valve seat 82 when the pressure difference between the upstream portion 61 and the downstream portion 62 is equal to or greater than the first predetermined value.

  According to this, when the temperature of the fuel supplied in the bypass passage 80 is lower than the first predetermined temperature and the fuel pressure difference of the upstream portion 61 with respect to the downstream portion 62 is equal to or greater than the first predetermined value, the bypass valve device 1 In addition, the temperature-sensitive valve body 20 and the pressure-sensitive valve body 30 open the bypass passage 80. Therefore, when the fuel filter 9a is clogged and this clogging is caused by wax, fuel can be supplied to the supply destination via the bypass passage 80.

  Thus, by using the temperature-sensitive valve body 20 and the pressure-sensitive valve body 30, it is possible to prevent a shortage of fuel supply due to wax precipitated from the fuel without using an electromagnetic valve, an electronic control device, or the like. In this way, it is possible to simplify the configuration for preventing fuel supply shortage due to the precipitated wax.

  When the supply pump 3 is driven, the pressure-sensitive valve body 30 is separated from the valve seat 82 when the pressure difference between the upstream portion 61 and the downstream portion 62 becomes equal to or greater than the first predetermined value. However, when the temperature of the fuel supplied in the bypass passage 80 is relatively high and the temperature-sensitive valve body 20 is seated on the valve seat 81, the bypass passage 80 remains closed as shown in FIG. Therefore, the bypass passage 80 can be prevented from opening when the fuel filter 9a is clogged with solid foreign matters other than wax that are difficult to be eliminated in a short time.

  Further, the temperature sensing valve body 20 is separated from the valve seat 81 when the temperature of the supplied fuel in the bypass passage 80 falls below the first predetermined temperature, and the temperature of the supplied fuel in the bypass passage 80 is the first predetermined temperature. When the temperature rises above a second predetermined temperature higher than the predetermined temperature, the valve seat 81 is seated.

  According to this, it is possible to prevent the temperature-sensitive valve body 20 from chattering on the valve seat 81 by making the seating temperature and the separation temperature of the temperature-sensitive valve body 20 different from each other. Further, the fuel can be supplied to the supply destination via the bypass passage 80 at a low temperature when the temperature of the supplied fuel becomes lower than the first predetermined temperature. In addition, when the temperature of the supplied fuel becomes equal to or higher than a second predetermined temperature at which clogging due to wax does not occur reliably, the fuel can be supplied to the supply destination via the fuel filter 9a.

  Further, the temperature sensitive valve body 20 is made of a bimetal plate. According to this, the temperature sensitive valve body 20 can be easily comprised using a bimetal plate.

  Further, the bypass passage upstream portion 80a on the fuel flow upstream side of the valve seat 82 of the bypass passage 80 communicates with the upstream portion 61 of the fuel passage 60, and the pressure sensitive valve body 30 includes the bypass passage upstream portion 80a, The fuel passage 60 is displaced according to the pressure difference with the downstream portion 62. According to this, by disposing the pressure sensitive valve body so as to contact the fuel in the upstream portion 80a of the bypass passage and the fuel in the downstream portion 62 of the fuel passage 60, the upstream portion of the fuel passage 60 more easily than the fuel filter 9a. The pressure difference between 61 and the downstream portion 62 can be sensed and displaced.

  The pressure-sensitive valve body 30 is separated from the valve seat 82 when the pressure difference between the upstream portion 61 and the downstream portion 62 is equal to or greater than a first predetermined value, and the second predetermined pressure is smaller than the first predetermined value. When it becomes less than the value, it sits on the valve seat 82.

  According to this, it is possible to prevent the pressure-sensitive valve body 30 from chattering on the valve seat 82 by making the seating pressure difference and the separation pressure difference between the pressure-sensitive valve body 30 and the valve seat 82 different. Further, the bypass passage 80 can be opened when the fuel filter 9a is clogged when the pressure difference between the upstream portion 61 and the downstream portion 62 of the fuel filter 9a is equal to or greater than the first predetermined value. In addition, when the pressure difference between the upstream portion 61 and the downstream portion 62 is less than a second predetermined value at which clogging is reliably eliminated, the bypass passage 80 is closed and the fuel filter 9a is interposed. The fuel can be supplied to the supplier.

  The pressure-sensitive valve body 30 includes a curved plate portion 31 that is a curved plate member whose bending direction is reversed according to the pressure difference between the upstream portion 61 and the downstream portion 62. According to this, the pressure-sensitive valve body 30 can be easily configured using the curved plate member whose bending direction is reversed.

(Other embodiments)
The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  In the above embodiment, the temperature sensing valve body 20 that is a temperature sensing valve body is composed of only a bimetal plate, but is not limited thereto. For example, what is necessary is just to include a bimetal plate. A valve body in which a needle valve portion is integrated with a bimetal plate may be used. Further, the temperature sensing valve element is not limited to one using a bimetal plate. For example, the rod valve portion may be displaced by changing the volume of wax sealed in the container body.

  In the above-described embodiment, the pressure-sensitive valve body 30 that is a differential pressure sensing valve body is configured such that the needle portion 32 integrated with the curved plate portion 31 that is a curved plate member is attached to and detached from the valve seat 82. However, the present invention is not limited to this. For example, the curved plate member may be directly detached from the valve seat without having the needle portion. Further, the differential pressure sensing valve body may not have a curved plate member. For example, a valve body that has a diaphragm or a bellows and can be displaced according to a pressure difference may be used.

  Moreover, in the said embodiment, although the pressure sensitive valve body 30 was displaced according to the pressure difference of the upstream part 80a of the bypass channel 80, and the downstream part 62 of the fuel channel 60, it is not limited to this. Absent. Any device that senses and displaces the pressure difference between the upstream portion 61 and the downstream portion 62 relative to the fuel filter 9a in the fuel passage 60 may be used.

  Moreover, in the said embodiment, although the temperature-sensitive valve body 20 differed in valve opening operation temperature and valve closing operation temperature, it is not limited to this. It may be a temperature sensing valve body in which the valve opening operating temperature and the valve closing operating temperature are the same. Further, the pressure-sensitive valve body 30 has a valve opening operation pressure difference and a valve closing operation pressure difference different from each other, but is not limited thereto. A differential pressure sensing valve body in which the valve opening operating pressure difference and the valve closing operating pressure difference are the same may be used.

  In the above-described embodiment, the bypass valve device 1 is configured such that the valve seat 82 on which the pressure-sensitive valve body 30 is seated on and off the valve seat 81 on which the temperature-sensing valve body 20 is seated on and off is located downstream of the bypass passage 80 in the fuel flow. However, the present invention is not limited to this. A valve seat 82 on which the pressure-sensitive valve body 30 is seated on and off with respect to the valve seat 81 on which the temperature-sensitive valve body 20 is seated on and off may be provided on the fuel flow upstream side of the bypass passage 80. The valve seat 81 and the valve seat 82 may be provided in series in the bypass passage 80.

  Moreover, in the said embodiment, although the bypass valve apparatus 1 was provided with the temperature sensitive valve body 20 and the pressure sensitive valve body 30, it is not limited to this. The pressure-sensitive valve body 30 may not be provided.

  That is, a valve seat formed so as to face the bypass passage, and a temperature sensing valve that senses and displaces the temperature of the fuel supplied in the bypass passage, and opens and closes the bypass passage by moving to and from the valve seat in accordance with this displacement. What is necessary is just to have a body. And the temperature sensing valve body should just be separated from a valve seat, when the temperature of the fuel supplied in a bypass channel falls below predetermined temperature.

  According to this, when the temperature of the supply fuel in the bypass passage becomes lower than the predetermined temperature, the temperature sensing valve body is separated from the valve seat to open the bypass passage, and is supplied from the fuel tank without passing through the fuel filter. Supply fuel first. Therefore, even if the fuel filter is clogged with the wax precipitated in the fuel at a low temperature, the fuel can be supplied to the supply destination through the bypass passage. Thus, by using the temperature sensing valve body, it is possible to prevent insufficient fuel supply at low temperatures without using an electromagnetic valve, an electronic control device, or the like. In this way, it is possible to simplify the configuration for preventing fuel supply shortage at low temperatures.

  Moreover, in the said embodiment, although the diesel fuel supply apparatus was a common rail type fuel injection system and the supply destination of the supply fuel was the supply pump 3, etc., it is not limited to this. For example, the supply destination of the supplied fuel may be pump means such as a distributed fuel injection pump.

1 Bypass valve device (bypass passage opening and closing device)
2 Fuel tank 3 Supply pump (supplier)
4 Common rail (supplier)
5 Injector (supplier)
9a Fuel filter 20 Temperature sensing valve (temperature sensing valve)
30 Pressure Sensitive Valve (Differential Pressure Sensing Valve)
60 Fuel passage 80 Bypass passage 81 Valve seat (first valve seat)
82 Valve seat (second valve seat)

Claims (7)

A fuel passage (60) through which the fuel supplied from the fuel tank (2) to the supply destination (3, 4, 5) is circulated;
A fuel filter (9a) for filtering the supplied fuel flowing through the fuel passage;
A bypass passage (80) for circulating the supplied fuel bypassing the fuel filter;
A valve seat (81) formed to face the bypass passage;
A temperature sensing valve element (20) that senses and displaces the temperature of the supplied fuel in the bypass passage, opens and closes the valve passage according to the displacement, and opens and closes the bypass passage;
The diesel fuel supply apparatus according to claim 1, wherein the temperature sensing valve body is separated from the valve seat when the temperature of the supply fuel in the bypass passage decreases below a predetermined temperature. When the predetermined temperature is the first predetermined temperature,
The temperature sensing valve body is separated from the valve seat when the temperature of the supply fuel in the bypass passage falls below the first predetermined temperature, and the temperature of the supply fuel in the bypass passage is the first temperature. 2. The diesel fuel supply device according to claim 1, wherein the diesel fuel supply device is seated on the valve seat when the temperature rises to a second predetermined temperature higher than a predetermined temperature.   The diesel fuel supply device according to claim 1, wherein the temperature sensing valve body includes a bimetal plate. When the valve seat is the first valve seat (81), the second valve seat (82) is positioned in series with the first valve seat with respect to the bypass passage so as to face the bypass passage. )When,
The pressure difference between the upstream side portion (61) and the downstream side portion (62) of the fuel passage from the fuel filter is sensed and displaced, and accompanying the displacement, the fuel passage is separated from and seated on the second valve seat, and the bypass passage. A differential pressure sensing valve body (30) that opens and closes,
The differential pressure sensing valve body is separated from the second valve seat when the pressure difference of the upstream side portion with respect to the downstream side portion exceeds a predetermined value. 4. The diesel fuel supply apparatus according to any one of 3. The bypass passage upstream portion (80a) on the fuel flow upstream side of the second valve seat of the bypass passage communicates with the upstream side portion (61),
The diesel fuel supply apparatus according to claim 4, wherein the differential pressure sensing valve body is displaced according to a pressure difference between the upstream portion of the bypass passage and the downstream portion. When the predetermined value is the first predetermined value,
The differential pressure sensing valve body is separated from the second valve seat when the pressure difference becomes equal to or greater than the first predetermined value, and the second predetermined value is smaller than the first predetermined value. 6. The diesel fuel supply device according to claim 4 or 5, wherein the diesel fuel supply device is seated on the second valve seat when it becomes less than the value.   The diesel fuel supply according to any one of claims 4 to 6, wherein the differential pressure sensing valve body includes a curved plate member (31) whose bending direction is reversed according to the pressure difference. apparatus.

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