JP2012251467A - Fuel pressure pulsation reducing mechanism and high-pressure fuel supply pump of internal combustion engine equipped with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To expand a reduction area of pressure pulsation generated at a low-pressure fuel passage, and to supply stable fuel to a high-pressure fuel supply pump by solving a problem that a metal damper itself cannot sufficiently absorb pressure pulsation at an extremely-low rotation side while the damper has an effect in the reduction of the pressure pulsation of the low-pressure fuel passage in a high-rotation region from a middle-rotation region of an internal combustion engine.SOLUTION: The metal damper itself sealed with gas by joining two pieces of metal diaphragms is elastically supported between both or one of outside surfaces of the metal damper and a cover of an accommodation chamber or a pump body via an elastic member so that the metal damper can move in the damper accommodation chamber. The pressure pulsation in the high-rotation region from the middle-rotation region of the internal combustion engine is absorbed by a change of a volume of the metal diaphragm damper, and the metal damper itself moves following a flow of fuel in a damper chamber, thus reducing the pressure pulsation relatively low in frequency in the extremely-low rotation region from the middle-rotation region.

Description

  The present invention relates to a high-pressure fuel supply pump used for an in-cylinder direct fuel injection internal combustion engine, and more particularly to a pressure pulsation reduction mechanism provided in a low-pressure fuel passage leading to a pressurizing chamber.

  The conventional pressure pulsation reduction mechanism is configured to join two metal diaphragms and sandwich a metal damper filled with gas between a damper chamber provided in the pump body and a cover attached to the body. Has been.

  The damper chamber is formed in a low-pressure fuel passage leading to the pressurizing chamber of the high-pressure fuel supply pump, and is connected to a fuel return passage from the suction joint, the suction valve, and the plunger seal chamber.

  Specifically, the pressure pulsation reducing mechanism is an annular flat plate part in which two metal diaphragms are overlapped between a disk-shaped bulge part in which two metal diaphragms are welded on the outer periphery and gas is sealed in the center. Serve. And the both outer surfaces of this flat plate part are sandwiched between thick parts provided on the cover and the main body, or the elastic pair is sandwiched between the cover and the annular flat plate part and the main body and the annular flat plate part It has been known.

  Further, high pressure fuel supply pumps having such a fuel pressure pulsation reduction mechanism are also known. Examples of such decentralization are Japanese Patent Application Laid-Open Nos. 2004-138071, 2006-521487, and 2003-254191. And Japanese Patent Application Laid-Open No. 2005-42554.

JP 2004-138071 A JP-T-2006-521487 JP 2003-254191 A JP 2005-42554 A

  In the above prior art, both surfaces of the damper are fixed by the holding members so that the metal diaphragm damper cannot move.

  The metal damper itself is designed to reduce the pressure pulsation with large amplitude of the low pressure fuel passage in the medium to high rotation range of the internal combustion engine, and has a small amplitude on the extremely low rotation side when starting the internal combustion engine. The pressure pulsation is designed so that it cannot be absorbed sufficiently.

  It is an object of the present invention to expand a reduction range of pressure pulsation generated in a low pressure fuel passage and to supply stable fuel to a high pressure fuel supply pump.

  In the present invention, in order to achieve the above object, both the outer surfaces of the metal damper or both of the outer surfaces of the metal damper are joined so that the metal damper itself, in which two metal diaphragms are sealed and gas is enclosed inside, can move in the damper storage chamber. A metal damper was elastically held via an elastic member between one side and the cover of the storage chamber or the pump body.

  With this configuration, the volume change of the metal diaphragm damper absorbs the pressure pulsation having a relatively large amplitude in the low pressure fuel passage in the medium rotation region to the high rotation region of the internal combustion engine, and the metal damper itself flows into the fuel in the damper chamber. By following and moving, pressure pulsations having a relatively small amplitude in the region from the middle rotation to the extremely low rotation can be reduced.

1 is an example of a fuel supply system using a high-pressure fuel supply pump according to a first embodiment in which the present invention is implemented. It is a longitudinal cross-sectional view of the high pressure fuel supply pump by 1st Example with which this invention was implemented. It is the figure which showed the movement of the suction valve and fuel. It is the figure which showed the movement of the intake valve and fuel by 1st Example with which this invention was implemented. FIG. 6 shows the effect of reducing suction pressure pulsation generated by the high-pressure fuel supply pump according to the first embodiment in which the present invention is implemented. FIG. It is a longitudinal cross-sectional view of the high pressure fuel supply pump by 2nd Example by which this invention was implemented, Comprising: It is an enlarged view of the part especially related to a metal diaphragm damper. It is a longitudinal cross-sectional view of the high pressure fuel supply pump by 3rd Example by which this invention was implemented, Comprising: It is an enlarged view of the part especially related to a metal diaphragm damper. It is a longitudinal cross-sectional view of the high pressure fuel supply pump by 4th Example by which this invention was implemented, Comprising: It is an enlarged view of the part especially related to a metal diaphragm damper.

  Hereinafter, examples will be described with reference to the drawings.

  A first embodiment of the present invention will be described. First, the basic operation of the high-pressure fuel pump will be described with reference to FIGS.

  FIG. 1 shows a fuel supply system including a high-pressure fuel supply pump.

  FIG. 2 shows a longitudinal sectional view of the high-pressure fuel supply pump.

  In FIG. 1, a portion surrounded by a broken line indicates a pump housing 1 of the high-pressure pump, and the mechanisms and components shown in the broken line are integrally incorporated in the pump housing 1 of the high-pressure pump.

  The fuel in the fuel tank 20 is pumped up by the feed pump 21 based on a signal from an engine control unit 27 (hereinafter referred to as ECU), pressurized to an appropriate feed pressure, and passed through the suction pipe 28 to the low pressure fuel flow of the high pressure fuel supply pump. Sent to the road 10a.

  The fuel that has passed through the low-pressure fuel flow path 10a passes through the suction filter 102 fixed in the suction joint 101, and further, electromagnetic suction that constitutes a variable capacity mechanism via the metal diaphragm damper 9 and the low-pressure fuel flow paths 10b and 10c. It reaches the suction port 30a of the valve mechanism 30.

  The suction filter 102 in the suction joint 101 serves to prevent foreign matter existing between the fuel tank 20 and the low-pressure fuel flow path 10a from being absorbed into the high-pressure fuel supply pump by the flow of fuel.

  The cover 14 to which the suction joint 101 is attached is fixed to an annular surface 122 formed on the outer wall of the pump body 1 by laser welding. Thus, a storage chamber for storing the metal diaphragm damper 9 is formed between the cover 14 and the pump body 1 by the low-pressure fuel flow paths 10b and 10c.

  Details of the metal diaphragm damper 9 for reducing pressure pulsation will be described later.

  The electromagnetic intake valve mechanism 30 includes an electromagnetic coil 30b. When the electromagnetic coil 30b is energized, the electromagnetic plunger 30c is moved rightward in FIG. 1, and the compressed state of the spring 33 is maintained.

  At this time, the suction valve 31 attached to the tip of the electromagnetic plunger 30c opens the suction port 32 connected to the pressurizing chamber 11 of the high-pressure pump.

  When the electromagnetic coil 30 b is not energized and there is no fluid differential pressure between the low pressure fuel flow path 10 c (suction port 30 a) and the pressurizing chamber 11, the suction valve 31 is urged by the biasing force of the spring 33. Is energized in the valve closing direction, and the suction port 32 is closed.

  When the plunger 2 is in the suction process state in which the plunger 2 is displaced downward in FIG. 2 due to the rotation of the cam described later, the volume of the pressurizing chamber 11 increases and the fuel pressure in the pressurizing chamber 11 decreases. In this process, when the fuel pressure in the pressurizing chamber 11 becomes lower than the pressure in the low-pressure fuel flow path 10c (suction port 30a), the suction valve 31 has a valve opening force (suction valve 31 shown in FIG. Force to displace to the right).

  By the valve opening force due to the fluid differential pressure, the suction valve 31 is set to open over the biasing force of the spring 33 and open the suction port 32.

  In this state, when a control signal from the ECU 27 is applied to the electromagnetic intake valve 30, an electric current flows through the electromagnetic coil 30b of the electromagnetic intake valve 30, and the electromagnetic plunger 30c is moved to the right in FIG. The spring 33 is maintained in a compressed state. As a result, the state in which the suction valve 31 opens the suction port 32 is maintained.

  When the plunger 2 finishes the suction process while maintaining the application state of the input voltage to the electromagnetic suction valve 30 and moves to the compression process in which the plunger 2 is displaced upward in FIG. 2, the magnetic urging force remains maintained. Still, the suction valve 31 remains open.

  Although the volume of the pressurizing chamber 11 decreases as the plunger 2 compresses, in this state, the fuel once sucked into the pressurizing chamber 11 passes through the intake valve 31 that is opened again, and the low-pressure fuel flow path 10c ( Since the pressure is returned to the suction port 30a), the pressure in the pressurizing chamber does not increase. This process is called a return process.

  In this state, when the control signal from the ECU 27 is canceled and the energization to the electromagnetic coil 30b is cut off, the magnetic biasing force acting on the electromagnetic plunger 30c is after a certain time (after magnetic and mechanical delay time). Erased. Since the biasing force by the spring 33 is acting on the suction valve 31, the suction valve 31 closes the suction port 32 by the biasing force by the spring 33 when the electromagnetic force acting on the electromagnetic plunger 30 c disappears. When the suction port 32 is closed, the fuel pressure in the pressurizing chamber 11 increases with the upward movement of the plunger 2 from this time. When the pressure exceeds the pressure of the fuel discharge port 12, high pressure discharge of the fuel remaining in the pressurizing chamber 11 is performed via the discharge valve mechanism 8 and supplied to the common rail 23. This process is called a discharge process. That is, the compression process of the plunger 2 (the ascending process from the lower start point to the upper start point) includes a return process and a discharge process.

  And the quantity of the high pressure fuel discharged can be controlled by controlling the timing which cancels | releases the electricity supply to the electromagnetic coil 30c of the electromagnetic suction valve 30. FIG.

  If the timing of releasing the energization of the electromagnetic coil 30c is advanced, the ratio of the return process is small and the ratio of the discharge process is large during the compression process.

  That is, the amount of fuel returned to the low pressure fuel flow path 10c (suction port 30a) is small, and the amount of fuel discharged at high pressure is large.

  On the other hand, if the timing for releasing the input voltage is delayed, the ratio of the return process in the compression process is large and the ratio of the discharge process is small. That is, the amount of fuel returned to the low pressure fuel flow path 10c is large, and the amount of fuel discharged at high pressure is small. The timing for releasing the energization of the electromagnetic coil 30c is controlled by a command from the ECU.

  By configuring as described above, the amount of fuel discharged at a high pressure can be controlled to the amount required by the internal combustion engine by controlling the timing of releasing the energization of the electromagnetic coil 30c.

  Thus, the fuel guided to the low pressure fuel flow path 10a is pressurized to a high pressure by the reciprocating motion of the plunger 2 in the pressurizing chamber 11 of the pump body 1, and is pumped from the fuel discharge port 12 to the common rail 23. .

  An injector 24 and a pressure sensor 26 are attached to the common rail 23. The injectors 24 are mounted in accordance with the number of cylinders of the internal combustion engine, open and close according to a control signal from an engine control unit (ECU) 27, and inject fuel into the cylinders.

  The pump housing 1 is formed with a recess 1A as a pressurizing chamber 11 at the center, and a recess 11A for mounting the discharge valve mechanism 8 is formed between the inner peripheral wall of the pressurizing chamber 11 and the discharge port 12. Yes. Further, a hole 30A for mounting an electromagnetic suction valve mechanism 30 for supplying fuel to the pressurizing chamber 11 is provided on the outer wall of the pump housing on the same axis as the recess 11A for mounting the discharge valve mechanism 8. .

  With respect to the central axis of the recess 1A as the pressurizing chamber 11, the recess 11A for mounting the discharge valve mechanism 8 and the axis of the hole for attaching the electromagnetic suction valve mechanism 30 are formed in a direction intersecting, A discharge valve mechanism 8 for discharging fuel from the discharge passage 11 is provided.

  A cylinder 6 that guides the reciprocating motion of the plunger 2 is attached so as to face the pressurizing chamber.

  A discharge valve mechanism 8 is provided at the outlet of the pressurizing chamber 11. The discharge valve mechanism 8 includes a sheet member (sheet member) 8a, a discharge valve 8b, a discharge valve spring 8c, and a holding member 8d as a discharge valve stopper.

  In a state where there is no fuel differential pressure between the pressurizing chamber 11 and the discharge port 12, the discharge valve 8b is pressed against the seat member 8a by the urging force of the discharge valve spring 8c and is in a closed state. Only when the fuel pressure in the pressurizing chamber 11 becomes larger than the fuel pressure in the discharge port 12 by a predetermined value, the discharge valve 8b is opened against the discharge valve spring 8c, and the pressure in the pressurizing chamber 11 is increased. The fuel is discharged to the common rail 23 through the discharge port 12.

  When the discharge valve 8b is opened, the discharge valve 8b comes into contact with the holding member 8d and its operation is restricted. Therefore, the stroke of the discharge valve 8b is appropriately determined by the holding member 8d. If the stroke is too large, the fuel discharged to the fuel discharge port 12 will flow back into the pressurizing chamber 11 again due to the delay in closing the discharge valve 8b, and the efficiency of the high-pressure pump will decrease. . Further, when the discharge valve 8b repeats opening and closing movements, the holding member 8d guides the discharge valve 8b to move only in the stroke direction. By configuring as described above, the discharge valve mechanism 8 becomes a check valve that restricts the flow direction of fuel.

  The high pressure fuel supply pump is fixed to the engine by the flange 41 and the bush 43. The flange 41 is fixed to the engine by a set screw 42 via a bush 43. Since the inner periphery of the flange 41 is fixed to the pump housing 1 by welding, the pump housing 1 is thereby fixed to the engine.

  The pump housing 1 is further provided with a relief passage communicating with the downstream side of the discharge valve 8b and the low-pressure fuel passage 10c.

  The relief passage is provided with a relief valve mechanism (not shown) that restricts the flow of fuel in only one direction from the discharge passage to the low-pressure fuel passage 10c, and the relief valve mechanism entrance communicates with the downstream side of the discharge valve 8b. Yes.

  The relief valve mechanism is composed of a valve, a valve seat, and a spring, and a set load of the spring is set so as to open at a predetermined pressure.

  When the abnormal high pressure in the common rail 23 caused by the failure of the fuel injection valve that supplies fuel to the engine or the failure of the ECU 27 that controls the fuel injection valve, the high-pressure fuel supply pump, etc. exceeds the set opening pressure of the Lily valve The fuel passes through the relief flow path from the downstream side of the discharge valve 8b and reaches the relief valve. And the fuel which passed the relief valve is open | released by the low pressure fuel flow path 10c which is a low pressure part. As a result, the high-voltage portion such as the common rail 23 is protected.

  The outer periphery of the cylinder 6 is held by a cylinder holder 7, and the cylinder holder 7 is fixed to the pump housing 1 by screwing a screw threaded on the outer periphery into a screw threaded on the pump housing 1. The cylinder 6 holds the plunger 2 that moves forward and backward in the pressurizing chamber 11 so as to be slidable along the forward and backward movement direction.

  The lower end of the plunger 2 is provided with a tappet 3 that converts the rotational motion of the cam 5 attached to the camshaft of the engine into a vertical motion and transmits it to the plunger 2. The plunger 2 is pressure-bonded to the tappet 3 by a spring 4 through a retainer 15. The retainer 15 is fixed to the plunger 2 by press-fitting. Thereby, the plunger 2 can be moved back and forth (reciprocated) up and down with the rotational movement of the cam 5.

  Further, the plunger seal 13 held at the lower end of the inner periphery of the cylinder holder 7 is installed in a state in which the plunger seal 13 is slidably in contact with the outer periphery of the plunger 2 at the lower end of the cylinder 6 in the figure. Is prevented from flowing into the tappet 3 side, that is, inside the engine. At the same time, lubricating oil (including engine oil) for lubricating the sliding portion in the engine room is prevented from flowing into the pump body 1.

  Here, the low pressure fuel flow path 10c is connected to the seal chamber 10f via the low pressure fuel flow path 10e provided in the cylinder 6, and the seal chamber 10f is always connected to the pressure of the intake fuel. When the fuel in the pressurizing chamber 11 is pressurized to a high pressure, a minute amount of high-pressure fuel flows into the seal chamber 10f through the sliding clearance between the cylinder 6 and the plunger 2, but the inflowed high-pressure fuel is released to the suction pressure. Therefore, the plunger seal 13 is not damaged by the high pressure.

  The plunger 2 is formed with a thick portion that slides into the cylinder and a thin portion that is fitted with the plunger seal. In the seal chamber 10f, the connecting portion (stepped portion) between the thick portion and the thin portion reciprocates so that the fuel in the seal chamber 10f passes through the low pressure fuel flow path 10e and the low pressure in which the damper is stored. It is sent out to the fuel flow path 10c.

  Further, when the plunger 2 moves upward, the low pressure fuel flows from the low pressure fuel passage 10c into the seal chamber 10f. Thus, in the low pressure fuel passage 10c to which the metal diaphragm damper 9 is mounted, the fuel flow that flows into the pressurizing chamber 11 through the low pressure fuel passage 10a, the low pressure fuel passage 10e, and the suction valve 31, and the fuel that spills from the pressurizing chamber 11. Four members of the flow join to generate a complex low pressure pulsation.

  Since the metal diaphragm damper 9 is designed to reduce the pulsation of the low-pressure fuel passage when the internal combustion engine is operated at a medium to high speed, the metal diaphragm damper 9 is operated at an extremely low speed (for example, 500 rpm or less) of the internal combustion engine. The metal diaphragm damper 9 is not deformed by the amplitude of the pulsation of the low pressure fuel passage when it is being performed.

  Hereinafter, a mechanism for reducing the pressure pulsation on the low pressure side will be described with reference to FIGS.

  FIG. 4 shows the relationship between the movement of the plunger 2, the movement of the intake valve 31, and the fuel flow.

  The top table shows the movement of the plunger 2, and T.D.C (abbreviation of TOP DEAD CENTER) is when the position of the plunger 2 comes to the top in FIG. 4, and B.D.C (BOTTOM (Abbreviation of DEAD CENTER) indicates when the position of the plunger 2 is at the lowest position. When the plunger 2 is in the downward movement, it consists of a suction process, and during the upward movement, it consists of a return process and a discharge process.

  The lower table shows the energization timing of the electromagnetic coil 30b of the electromagnetic intake valve mechanism 30 and the opening / closing operation of the intake valve 31. When the electromagnetic coil 30b is energized in the lowering process of the plunger 2, the intake valve 31 opens. It becomes an inhalation process. Next, even if the plunger 2 enters the ascending process, the returning process is performed while the electromagnetic coil 30b is energized and the suction valve 31 is kept open. Finally, when the energization of the electromagnetic coil 30b is turned off, the suction valve 31 is closed and the pressurization process is started.

  The figure below it shows the flow of fuel.

  Next, the state during each step of the fuel flow will be described.

<Inhalation process>
(1) The volume of the pressurizing chamber 11 is increased by the downward movement of the plunger 2, and the fuel corresponding to the increased volume flows into the high-pressure fuel supply pump from the low-pressure fuel flow path 10c.

<Return (spill) process>
(1) The volume of the pressurizing chamber 11 is reduced by the upward movement of the plunger 2, and the fuel corresponding to the volume reduction flows out to the low pressure fuel flow path 10c.

<Discharge process>
(1) The volume of the pressurizing chamber 11 is reduced by the upward movement of the plunger 2, and the fuel in the pressurizing chamber 11 is pressurized to a high pressure. Then, it is supplied to the common rail 23 through the discharge valve mechanism 8 and the fuel discharge port 12. In this case, the volume in the pressurizing chamber 11 decreases, but no fuel flows between the low-pressure fuel flow path 10 c and the pressurizing chamber 11. Therefore, the amount of fuel flow is zero.

  The pressure pulsation generated in the suction flow path 28 between the feed pump 21 and the low pressure fuel flow path 10a relates to the fuel flowing from the low pressure fuel flow path 10a to the low pressure fuel flow path 10c.

  FIG. 4 shows the relationship between the movement of the plunger 2 of this embodiment, the movement of the intake valve 31 and the fuel flow.

  The pressure and volume on the upstream side of the damper chamber are P1 and V1, respectively, and the downstream side is P2 and V2.

  The metal diaphragm damper 9 is fixed to the damper chamber constituting member by an elastic holding member 116 (in this case, a spring).

  In the suction process, the fuel flows from the upstream side to the downstream side of the metal diaphragm damper 9, and the metal diaphragm damper 9 is held at a position where P1 and P2 are equal.

  Next, in the returning step, the fuel flow reverses and flows from the pressurizing chamber 11 into the low pressure fuel flow path 10c, so that the pressure P2 on the downstream side of the damper chamber increases. However, as the downstream pressure P2 increases, the metal diaphragm damper 9 moves to the upstream side and the damper chamber downstream volume V2 increases, so that an increase in the pressure P2 is suppressed.

  On the other hand, since the volume P1 decreases due to the movement of the metal diaphragm damper 9 on the upstream side, the pressure P1 rises accordingly, and the metal diaphragm damper 9 is held at a position where the pressures P1 and P2 become equal.

  In the discharging process, since there is no fuel flow in the damper chamber, the fuel is held at a position where the elastic forces of the upper and lower elastic holding members 116a and 116b are balanced.

  Thus, by supporting the metal diaphragm damper 9 itself so as to be able to move in accordance with the movement of the fuel, the pressure fluctuation of the low-pressure fuel flow path 10c in the suction and return process can be reduced. That is, the fuel pressure pulsation in the damper chamber is reduced, and the pressure pulsation generated in the suction passage 28 between the feed pump 21 and the low-pressure fuel passage 10a is also reduced.

  Next, the effect of reducing the low pressure pulsation is shown in FIG.

  The uppermost curve in FIG. 5 is a characteristic of the low pressure pulsation when the damper mechanism is not provided.

  The middle curve is a characteristic when the metal diaphragm damper 9 is provided, and the amplitude is reduced over the entire region.

  Furthermore, making the metal diaphragm damper 9 movable is effective in reducing the amplitude of the low rotation region that cannot be absorbed by the metal damper as shown in the lower curve of FIG.

  Next, a second embodiment of the present invention is shown in FIG.

  The difference between the second embodiment and the first embodiment is the difference between the elastic holding members 116a and 116b of the damper, and the material is made of an elastic resin. The elastic holding members 116a and 116b are formed in an annular shape, and a plurality of connection passages 108 for connecting the inside and the outside are provided at various places.

  Next, a third embodiment of the present invention is shown in FIG.

  In the third embodiment, the elastic holding members 116 a and 116 b provided on the upper and lower sides of the damper of the second embodiment are integrally molded with the metal diaphragm damper 9. The point that a plurality of connection passages 108 are provided is the same as in the second embodiment.

  Thereby, the number of parts and assembly man-hours can be reduced.

  Next, a fourth embodiment of the present invention is shown in FIG.

  In the fourth embodiment, one of the elastic holding members 116 of the damper is a non-elastic holding member 109 and is rigid.

  In FIG. 8, the upstream elastic holding member 116 is a spring, and the downstream inelastic holding member 109 is an annular protrusion formed on the pump body. In the case of this embodiment, a plurality of connection passages 108 that connect the low-pressure fuel flow path 10 b and the low-pressure fuel flow path 10 c are provided on the annular protrusion that constitutes the inelastic holding member 109.

  When the pressure on the low-pressure fuel flow path 10c side is increased in the return (spill) process, the metal diaphragm damper 9 is moved to the upstream side and held up to a position where the pressure difference between the upper and lower metal diaphragm dampers 9 and the load of the spring 116 are balanced. .

  Throughout all the embodiments, the inner side of the surrounding skirt portion 14A is press-fitted into the annular surface 122 of the outer periphery of the pump body 1, and the cover 14 is fixed by laser welding the entire periphery.

  At this time, part of the force when the cover 14 is press-fitted into the pump body 1 acts as a set load on the elastic holding members 116a and 116b so that the metal diaphragm damper 9 does not resonate due to vibration of the internal combustion engine. It is configured. Moreover, the set load of the elastic holding members 116, 116a, 116b can be adjusted by adjusting the press-fitting amount.

  According to this embodiment, as the rotation speed becomes higher, the pulsation cycle of the fuel in the suction passage becomes earlier (smaller), and the movement of the damper itself cannot follow (there is a slight movement of the damper within a followable range). In a medium to high rotation state, the amplitude of the fuel increases and the pulsation absorption effect due to the damper deformation increases. On the other hand, in the low speed region, particularly in the extremely low pressure region, the amplitude of the fuel becomes small and it becomes difficult for the damper to deform. However, in this state, the pulsation cycle of the fuel becomes slow (large), so the damper itself moves and is The pressure fluctuation can be suppressed.

  The present invention can be applied to various liquid transport systems as a damper mechanism for reducing liquid pulsation. In particular, it is suitable for use as a fuel pulsation reduction mechanism attached to a low pressure fuel passage of a high pressure fuel supply system that pressurizes gasoline and discharges it to an injector. Further, it can be integrally attached to the high-pressure fuel supply pump as in the embodiment.

8 Discharge valve mechanism 9 Metal diaphragm dampers 10a, 10b, 10c, 10e Low pressure fuel flow path 11 Pressurization chamber 31 Suction valve 101 Suction joint 109 Inelastic holding member 116, 116a, 116b Elastic holding member (spring)

Claims (10)

A suction passage for sucking fuel into the pressurization chamber; a discharge passage for discharging the fuel from the pressurization chamber; and a fuel reciprocating in the pressurization chamber for sucking and discharging fuel; A suction valve is provided in the suction flow path and a discharge valve is provided in the discharge flow path, and the pressure pulsation is reduced by changing the volume due to the pressure pulsation of the fuel in the suction flow path or in the low pressure chamber communicating with the suction flow path. In the high pressure fuel supply pump, which is a metal diaphragm damper in which two metal diaphragms are welded at the peripheral edge thereof and a gas is sealed between them, the pressure pulsation reduction damper is provided.
An elastic holding member is elastically supported between both or one of the outer surfaces of the metal damper and the cover or pump body of the storage chamber, and the metal damper itself moves following the pulsation of fuel in the storage chamber. A high-pressure fuel supply pump. In claim 1,
The high-pressure fuel supply pump, wherein the elastic holding member for holding the metal damper is a pair of upper and lower spring members. In claim 1,
The high-pressure fuel supply pump, wherein the elastic holding member for sandwiching the metal damper is a pair of upper and lower annular resin members. In what is described in claim 3,
The high-pressure fuel supply pump, wherein the pair of upper and lower annular resin members sandwiching the metal damper are integrally formed on an outer periphery of the metal damper. In any of claims 3 or 4,
The pair of upper and lower annular resin members is a high-pressure fuel supply pump having a connection passage portion that connects the inside and outside of the pair of upper and lower annular resin members. In a pressure pulsation reduction mechanism comprising a metal damper in a storage chamber formed by a body and a cover, and configured to flow a fluid having pulsation through the storage chamber,
The metal damper is elastically supported via an elastic holding member between both or one of the outer surfaces of the metal damper and the cover or body, and the metal damper itself follows the fuel pulsation in the storage chamber. The pressure pulsation reduction mechanism is characterized by moving. What is described in claim 6,
The high-pressure fuel supply pump, wherein the elastic holding member for holding the metal damper is a pair of upper and lower spring members. What is described in claim 6,
The high-pressure fuel supply pump, wherein the elastic holding member for sandwiching the metal damper is a pair of upper and lower annular resin members. What is described in claim 8,
The high-pressure fuel supply pump, wherein the pair of upper and lower annular resin members sandwiching the metal damper are integrally formed on an outer periphery of the metal damper. In any one of claims 8 or 9,
The pair of upper and lower annular resin members is a high-pressure fuel supply pump having a connection passage portion that connects the inside and outside of the pair of upper and lower annular resin members.