US20120195778A1 - High pressure pump - Google Patents
High pressure pump Download PDFInfo
- Publication number
- US20120195778A1 US20120195778A1 US13/352,626 US201213352626A US2012195778A1 US 20120195778 A1 US20120195778 A1 US 20120195778A1 US 201213352626 A US201213352626 A US 201213352626A US 2012195778 A1 US2012195778 A1 US 2012195778A1
- Authority
- US
- United States
- Prior art keywords
- plunger
- blocking wall
- chamber
- high pressure
- fuel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 230000000903 blocking effect Effects 0.000 claims abstract description 144
- 239000000446 fuel Substances 0.000 claims abstract description 111
- 239000007789 gas Substances 0.000 claims description 70
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 65
- 230000002093 peripheral effect Effects 0.000 claims description 46
- 229910001873 dinitrogen Inorganic materials 0.000 claims description 34
- 230000010349 pulsation Effects 0.000 claims description 27
- 239000012530 fluid Substances 0.000 claims description 5
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 4
- 238000009413 insulation Methods 0.000 claims description 4
- 229910052786 argon Inorganic materials 0.000 claims description 2
- 239000001307 helium Substances 0.000 claims description 2
- 229910052734 helium Inorganic materials 0.000 claims description 2
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 claims description 2
- 238000003466 welding Methods 0.000 description 16
- 238000009834 vaporization Methods 0.000 description 8
- 230000008016 vaporization Effects 0.000 description 8
- 230000007257 malfunction Effects 0.000 description 7
- 239000003921 oil Substances 0.000 description 6
- 238000002485 combustion reaction Methods 0.000 description 5
- 239000010687 lubricating oil Substances 0.000 description 5
- 230000003247 decreasing effect Effects 0.000 description 4
- 239000000696 magnetic material Substances 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 230000001603 reducing effect Effects 0.000 description 4
- 238000011144 upstream manufacturing Methods 0.000 description 4
- 239000002828 fuel tank Substances 0.000 description 3
- 239000004809 Teflon Substances 0.000 description 2
- 229920006362 Teflon® Polymers 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000007246 mechanism Effects 0.000 description 2
- 239000007769 metal material Substances 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 239000010705 motor oil Substances 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 230000004044 response Effects 0.000 description 2
- 239000011343 solid material Substances 0.000 description 2
- 230000008859 change Effects 0.000 description 1
- 229920002313 fluoropolymer Polymers 0.000 description 1
- 239000004811 fluoropolymer Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
- F04B1/04—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinders in star- or fan-arrangement
- F04B1/0404—Details or component parts
- F04B1/0408—Pistons
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
- F04B1/04—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinders in star- or fan-arrangement
- F04B1/0404—Details or component parts
- F04B1/0421—Cylinders
Definitions
- the present invention relates to a high pressure pump.
- a high pressure pump which supplies fuel to a fuel supply system of an internal combustion engine, is known.
- Fuel which is drawn out of a fuel tank, is drawn into a pressurizing chamber upon downward movement of a plunger in a cylinder hole of the high pressure pump and is metered upon upward movement of the plunger in the cylinder hole.
- a damper chamber pressure dumper
- a variable volume chamber compression chamber
- the variable volume chamber (the compensation chamber) is covered by only a portion (sleeve part) of a seal element (stop element). Therefore, the fuel in the variable volume chamber may be heated by heat, which is conducted from a heated engine head located adjacent to a cam that reciprocates a plunger. Also, the fuel in the variable volume chamber may be heated by lubricating oil (including engine oil), which is initially applied to the cam or therearound and is dispersed over the seal element. When the fuel in the variable volume chamber is heated to the high temperature in this way, the fuel may possibly be vaporized. When the fuel in the variable volume chamber is vaporized, the high pressure pump may have a difficulty of drawing fuel, so that the operational malfunction of the high pressure pump may occur.
- the present invention addresses the above disadvantages.
- a high pressure pump which includes a plunger, a pump body, variable volume chamber forming means and a gas chamber.
- the pump body includes a cylinder hole, a pressurizing chamber, a low pressure fuel passage and a discharge passage.
- the plunger is adapted to reciprocate in an axial direction thereof in the cylinder hole.
- the pressurizing chamber is communicated with the cylinder hole, and fuel is pressurized in the pressurizing chamber by reciprocating movement of the plunger.
- the low pressure fuel passage communicates between the pressurizing chamber and a fuel inlet.
- the discharge passage communicates between the pressurizing chamber and a fuel outlet.
- the variable volume chamber forming means is for forming a variable volume chamber, a volume of which changes by the reciprocating movement of the plunger.
- the variable volume chamber is placed adjacent to a step surface of the plunger.
- the step surface of the plunger is located between a large diameter portion of the plunger, which has an end portion exposed to the pressurizing chamber and is slidable along an inner peripheral wall surface of the cylinder hole, and a small diameter portion of the plunger, which extend from the large diameter portion in the axial direction on a side opposite from the pressurizing chamber.
- the gas chamber is placed adjacent to the variable volume chamber on a side of the variable volume chamber, which is opposite from the cylinder hole.
- the gas chamber may be formed in a recess of the pump body, which is configured into a generally annular form around the cylinder hole on a radially outer side of the cylinder hole.
- the gas chamber may include or may be formed at least by an inner blocking wall, an outer blocking wall and gas.
- the inner blocking wall borders on the variable volume chamber and contacts fuel in the variable volume chamber.
- the outer blocking wall is opposed to the inner blocking wall.
- the gas fills a space that is defined between the inner blocking wall and the outer blocking wall, and this space may be an open space or closed space.
- a seal member may be installed to the small diameter portion of the plunger to surround the small diameter portion in a circumferential direction.
- variable volume chamber forming means may include at least one or all of the step surface of the plunger, an outer peripheral wall of the small diameter portion, the inner peripheral wall of the cylinder hole of the pump body, an end portion of the seal member, a wall surface of the inner blocking wall and a wall surface of the recess of the pump body.
- FIG. 1 is a schematic longitudinal cross sectional view of a high pressure pump according to a first embodiment of the present invention
- FIG. 2 is an enlarged schematic cross-sectional view showing a plunger arrangement of the high pressure pump shown in FIG. 1 ;
- FIG. 3 is an enlarged schematic cross-sectional view showing a plunger arrangement of a high pressure pump according to a second embodiment of the present invention
- FIG. 4 is an enlarged schematic cross-sectional view showing a plunger arrangement of a high pressure pump according to a third embodiment of the present invention.
- FIG. 5 is an enlarged schematic cross-sectional view showing a plunger arrangement of a high pressure pump according to a fourth embodiment of the present invention.
- FIG. 1 shows a high pressure pump according to a first embodiment of the present invention.
- FIG. 2 shows a plunger arrangement of the high pressure pump.
- the high pressure pump 1 of the present embodiment will be described with reference to FIG. 1 .
- the high pressure pump 1 is provided in a fuel supply system, which supplies fuel to an internal combustion engine of a vehicle (e.g., an automobile).
- the fuel which is drawn from a fuel tank, is pressurized by the high pressure pump 1 and is stored in a delivery pipe.
- the fuel is injected from each corresponding injector, which is connected to the delivery pipe, into a corresponding cylinder of the internal combustion engine.
- the high pressure pump 1 includes a pump body 10 , a plunger arrangement 20 , a damper chamber 40 , an intake valve arrangement 50 , an electromagnetic drive arrangement 60 and a discharge valve arrangement 70 .
- the pump body 10 has a cylinder hole 11 and a pressurizing chamber 12 , which are communicated with each other and are formed integrally in the pump body 10 .
- a recess 13 which is configured into a generally annular form, is formed around the cylinder hole 11 on a radially outer side of the cylinder hole 11 , and a cylindrical tubular protrusion 10 a of the pump body 10 , which is axially downwardly protrudes in FIG. 2 , is radially interposed between the cylinder hole 11 and a space of the recess 13 located radially outward of the cylindrical tubular portion 10 a . Therefore, a lower end portion of the cylinder hole 11 is formed by the cylindrical tubular protrusion 10 a of the pump body 10 .
- the plunger arrangement 20 includes a plunger 21 , a seal member 24 , a seal element 25 , a plunger spring 28 and a variable volume chamber 30 .
- the plunger 21 is received in the cylinder hole 11 such that the plunger 21 is adapted to be axially reciprocated in an axial direction of the plunger 21 in the cylinder hole 11 .
- the plunger 21 has a large diameter portion 211 and a small diameter portion 212 .
- One end portion of the large diameter portion 211 is connected the small diameter portion 212 , and the other end portion of the large diameter portion 211 is exposed to the pressurizing chamber 12 .
- the large diameter portion 211 is slidable along an inner peripheral wall of the cylinder hole 11 .
- the small diameter portion 212 has an outer diameter smaller than that of the large diameter portion 211 and axially extends from the large diameter portion 211 on a side, which is axially opposite from the pressurizing chamber 12 .
- the large diameter portion 211 and the small diameter portion 212 are coaxial with each other, and a step surface 213 is formed between the large diameter portion 211 and the small diameter portion 212 .
- a spring seat 27 is installed to one end portion 22 of the small diameter portion 212 , which is opposite from the large diameter portion 211 .
- the seal member 24 is installed around the small diameter portion 212 of the plunger 21 such that the seal member 24 surrounds the small diameter portion 212 in a circumferential direction on a radially outer side of the small diameter portion 212 .
- the seal member 24 includes a ring (Teflon ring, the name “Teflon” being a registered trademark of DuPont for its brand of fluoropolymer resins) and an O-ring.
- the ring is placed on a radially inner side and slidably contacts an outer peripheral surface of the small diameter portion 212 , and the O-ring is placed on a radially outer side of the ring.
- the seal member 24 limits a thickness of a fuel film, which is formed around the small diameter portion 212 , and also limits leakage of fuel toward the engine caused by the slide movement of the plunger 21 .
- the seal element 25 is installed around a portion of the small diameter portion 212 , which is located on the spring seat 27 side of the seal member 24 , such that the seal element 25 surrounds the small diameter portion 212 in the circumferential direction on the radially outer side of the small diameter portion 212 .
- the seal element 25 is configured into a generally annular form. A portion of the seal element 25 is installed to and is secured to the recess 13 of the pump body 10 .
- seal element 25 contacts both of one end portion of the seal member 24 , which is axially located on the spring seat 27 side, and a radially outer end portion of the seal member 24 , i.e., an outer peripheral portion of the seal member 24 , which is radially located on the side opposite from the small diameter portion 212 .
- the seal element 25 serves as a holder, which securely holds the seal member 24 .
- An oil seal 26 is installed to one end portion of the seal element 25 , which is axially located on the spring seat 27 side.
- the oil seal 26 surrounds the small diameter portion 212 in the circumferential direction.
- the oil seal 26 slidably contacts an outer peripheral surface of the small diameter portion 212 .
- the oil seal 26 limits a thickness of an oil film, which is formed around the small diameter portion 212 , and limits leakage of the oil caused by the slide movement of the plunger 21 .
- the spring seat 27 is securely held by the lower end portion 22 of the plunger 21 .
- One end portion of the plunger spring 28 is engaged to the spring seat 27 .
- the other end portion of the plunger spring 28 is engaged to a predetermined end surface of the seat element 25 , which is fixed to the pump body 10 .
- the seal element 25 also functions as an engaging member of the plunger spring 28 .
- the plunger spring 28 which is engaged to the seal element 25 and the spring seat 27 at the opposite ends, respectively, of the plunger spring 28 , functions as a return spring of the plunger 21 to urge the plunger 21 against a tapped (not shown).
- the plunger 21 is urged against the cam of the camshaft through the tappet by the returning spring function of the plunger spring 28 , i.e., the urging force of the plunger spring 28 , so that the plunger 21 is axially reciprocated in the cylinder hole 11 upon the rotation of the camshaft.
- the volume of the pressurizing chamber 12 is changed by the reciprocating movement of the plunger 21 , so that the fuel is drawn into and pressurized in the pressurizing chamber 12 .
- the variable volume chamber 30 is formed by a generally annular space, which is bounded by the step surface 213 of the plunger 21 , the outer peripheral wall of the small diameter portion 212 , the inner peripheral wall of the cylinder hole 11 of the pump body 10 , a wall surface of the recess 13 (including an outer peripheral wall surface of the cylindrical tubular protrusion 10 a of the pump body 10 ), and the other end portion of the seal member 24 axially located on the pressurizing chamber 12 side.
- the variable volume chamber 30 which is configured into the generally annular form, surrounds the cylinder hole 11 .
- the variable volume chamber 30 is in fluid communication with the damper chamber 40 through a return passage 31 , which is formed in the pump body 10 .
- a gas chamber 32 is located adjacent to the variable volume chamber 30 .
- the gas chamber 32 includes an inner blocking wall 33 , which is located adjacent to the variable volume chamber 30 .
- the inner blocking wall 33 is made of a resiliently deformable member.
- One end portion 331 of the inner blocking wall 33 which is axially located on the side opposite from the damper chamber 40 , extends in a direction generally perpendicular to the central axis of the cylinder hole 11 .
- the other end portion 332 of the inner blocking wall 33 which is axially located on the damper chamber 40 side, extends in a direction generally parallel to the central axis of the cylinder hole 11 .
- a peripheral wall of the one end portion 331 of the inner blocking wall 33 is welded to an inner peripheral surface of the seal element 25 at a welding portion 34 a all around the one end portion 331 in the circumferential direction (i.e., by the welding-all-around).
- An outer peripheral wall of the other end portion 332 of the inner blocking wall 33 is welded to the inner peripheral surface of the seal element 25 at a welding portion 34 b all around the other end portion 332 in the circumferential direction.
- a space 37 which is defined between the inner blocking wall 33 and the seal element 25 , is filled with nitrogen gas 35 and is airtightly sealed, so that the space 37 is a closed space filled with the nitrogen gas 35 .
- the inner blocking wall 33 , the seal element (serving as an outer blocking wall) 25 and the nitrogen gas 35 airtightly sealed in the space 37 therebetween form the gas chamber 32 .
- a wall surface of the one end portion 331 of the inner blocking wall 33 which is axially located on the pressurizing chamber 12 side, is axially opposed to the step surface 213 of the plunger 21 . Therefore, the one end portion 331 of the inner blocking wall 33 functions as a stopper, which limits the reciprocating movement of the plunger 21 in the cylinder hole 11 , particularly the downward movement of the plunger 21 in the cylinder hole 11 from the top dead center toward the bottom dead center thereof.
- the inner blocking wall 33 which contacts the other end portion of the seal member 24 axially located on the pressurizing chamber 12 side, cooperates with the seal element 25 , which contacts both of the one end portion of the seal member 24 axially located on the spring seat 27 side and the outer peripheral portion of the seal member 24 radially located on the side opposite from the small diameter portion 212 , to function as the holder, which securely holds, i.e., axially clamps the seal member 24 .
- the damper chamber 40 is formed by a recess 41 , a cover 42 and a damper unit 43 .
- the other end portion of the pump body 10 which is axially opposite from the cylinder hole 11 , is axially recessed toward the cylinder hole 11 side to form the recess 41 .
- the cover 42 which is configured into a cup form (a tubular body having a bottom), is installed to the pump body 10 to cover the recess 41 and thereby to seal an inside of the recess 41 from an external atmosphere.
- the damper unit 43 is placed in the damper chamber 40 .
- the damper unit 43 includes a pulsation damper 44 , a bottom side support portion 45 and a cover side support portion 46 .
- the pulsation damper 44 includes two metal diaphragms 441 , 442 , which are opposed to each other and are joined together.
- the bottom side support portion 45 is placed at a bottom portion of the recess 41 .
- the cover side support portion 46 is placed at the cover 42 side.
- gas of a predetermined pressure is sealed in an inside space, which is defined between the metal diaphragm 441 and the metal diaphragm 442 .
- the metal diaphragms 441 , 442 are resiliently deformed in response to a change in the pressure of the fuel in the damper chamber 40 , pressure pulsation of the fuel in the damper chamber 40 is damped (limited or alleviated).
- a recess 47 which is configured to correspond with the bottom side support portion 45 , is formed in the bottom portion of the recess 41 of the damper chamber 40 .
- the bottom side support portion 45 is positioned by the recess 47 .
- An opening of an inlet is formed in the recess 47 , so that the fuel, which is supplied from the low pressure pump, is supplied to a radially inner region of the bottom side support portion 45 through the inlet.
- the fuel of the fuel tank is supplied to the damper chamber 40 from the fuel inlet through the fuel passage.
- a wavy spring 48 is placed on the upper side of the cover side support portion 46 . Therefore, in the installed state where the cover 42 is installed to the pump body 10 , the wavy spring 48 urges the cover side support portion 46 toward the bottom side support portion 45 .
- the pulsation damper 44 is secured such that the pulsation damper 44 is clamped between the cover side support portion 46 and the bottom side support portion 45 by a generally uniform clamping force, which is generally uniform along the entire circumference of the pulsation damper 44 and is applied from the cover side support portion 46 and the bottom side support portion 45 .
- the intake valve arrangement 50 includes a supply passage 52 , a valve body 53 , a seat 54 and an intake valve 55 .
- the pump body 10 has a tubular portion 51 , which extends in a direction that is generally perpendicular to the central axis of the cylinder hole 11 .
- the supply passage 52 is formed in an inside of the tubular portion 51 .
- the valve body 53 is received in the tubular portion 51 and is fixed by an engaging member.
- the seat 54 is formed in the inside of the valve body 53 such that the seat 54 has a tapered inner peripheral concave surface.
- the intake valve 55 is placed such that the intake valve 55 is opposed to the seat 54 .
- the intake valve 55 is reciprocated such that the intake valve 55 is guided by an inner peripheral wall of a hole, which is formed in a bottom portion of the valve body 53 .
- the supply passage 52 is opened.
- the supply passage 52 is closed with the intake valve 55 .
- a stopper 56 is fixed to an inner peripheral wall of the valve body 53 such that the stopper 56 limits movement of the intake valve in a valve opening direction (the right direction in FIG. 1 ) of the intake valve 55 .
- a first spring 57 is placed between an inner portion of the stopper 56 and an end surface of the intake valve 55 . The first spring 57 urges the intake valve 55 in a valve closing direction (the left direction in FIG. 1 ).
- a plurality of tilted passages 58 is formed in the stopper 56 such that the tilted passages 58 are tilted relative to the axis of the stopper 56 and are arranged one after another in a circumferential direction.
- the fuel which is supplied through the supply passage 52 , is drawn into the pressurizing chamber 12 through the tilted passages 58 .
- the supply passage 52 is communicated with the damper chamber 40 through a pressurizing side passage 59 .
- the damper chamber 40 , the pressurizing side passage 59 , the supply passage 52 and the tilted passages 58 cooperate together to form a low pressure fuel passage, which communicates between the inlet and the pressurizing chamber 12 .
- the electromagnetic drive arrangement 60 includes a connector 61 , a stationary core 62 , a movable core 63 and a flange 64 .
- the connector 61 includes a coil 611 and terminals 612 .
- a magnetic field is generated from the coil 611 .
- the stationary core 62 is made of a magnetic material and is received in the inside of the coil 611 .
- the movable core 63 is made of a magnetic material and is opposed to the stationary core 62 .
- the movable core 63 is adapted to axially reciprocate at a location radially inward of the flange 64 .
- the flange 64 is made of a magnetic material and is installed to the tubular portion 51 of the pump body 10 .
- the flange 64 holds the connector 61 in corporation with the pump body 10 and closes an end portion of the tubular portion 51 .
- a guide tube 65 is installed to an inner peripheral wall of a hole, which is formed in a center of the flange 64 .
- a tubular member 66 which is made of a non-magnetic material, limits magnetic short circuit between the stationary core 62 and the flange 64 .
- a needle 67 is configured into a generally cylindrical tubular form and is guided by an inner peripheral wall of the guide tube 65 such that the needle 67 is adapted to be reciprocated along the inner peripheral wall of the guide tube 65 .
- One end portion of the needle 67 is fixed to the movable core 63 , and the other end portion of the needle 67 is contactable with an end surface of the intake valve 55 , which is located on a side where the electromagnetic drive arrangement 60 is located.
- a second spring 68 is placed between the stationary core 62 and the movable core 63 .
- the second spring 68 urges the movable core 63 in the valve opening direction by an urging force, which is larger than an urging force of the first spring 57 , which urges the intake valve 55 in the valve closing direction.
- the movable core 63 and the stationary core 62 are spaced from each other by a resilient force of the second spring 68 .
- the needle 67 which is integrated with the movable core 63 , is moved toward the intake valve 55 side to urge the intake valve 55 with the end surface of the needle 67 , so that the intake valve 55 is opened.
- the discharge valve arrangement 70 includes a discharge passage 71 and a discharge valve device 80 .
- the discharge passage 71 is formed in the pump body 10 such that the discharge passage 71 extends in a direction that is generally perpendicular to the central axis of the cylinder hole 11 .
- One end of the discharge passage 71 is communicated with the pressurizing chamber 12 , and the other end of the discharge passage 71 is communicated with a fuel outlet 72 .
- the discharge valve device 80 is installed to the discharge passage 71 .
- the discharge valve device 80 includes a discharge valve member 82 , a spring 83 and an adjusting pipe 84 .
- the discharge valve member 82 is received in the pump body 10 such that the discharge valve member 82 is opposed to a valve seat 85 of the pump body 10 .
- the spring 83 which serves as an urging member, is received in the pump body 10 on a fuel outlet 72 side of the discharge valve member 82 .
- One end portion of the spring 83 contacts an end surface (a right end surface in FIG. 1 ) of the discharge valve member 82 .
- the adjusting pipe 84 which is configured into a cylindrical tubular form, is received in the pump body 10 on a fuel outlet 72 side of the spring 83 .
- the adjusting pipe 84 serves as a support member such that the other end portion of the spring 83 is engaged to the adjusting pipe 84 .
- the discharge valve arrangement 70 includes the discharge valve device 80 .
- the discharge valve device 80 includes the discharge valve member 82 , the spring 83 and the adjusting pipe 84 , and the discharge valve member 82 is urged by the urging force of the spring 83 that is engaged to the adjusting pipe 84 at the other end portion of the spring 83 .
- the discharge valve device 80 of the discharge valve arrangement 70 is operated as follows.
- the pressure of the fuel in the pressurizing chamber 12 is increased.
- the force, which is applied to the discharge valve member 82 by the fuel on the pressurizing chamber 12 side (the upstream side) of the discharge valve member 82 becomes larger than a sum of the resilient force of the spring 83 and the force of the fuel on the fuel outlet 72 side (the downstream side) of the discharge valve member 82 , the discharge valve member 82 is lifted away from the valve seat 85 . That is, the discharge valve device 80 is placed into a valve open state. In this way, the high pressure fuel, which is pressurized in the pressurizing chamber 12 , is discharged to the fuel outlet 72 through the discharge passage 71 .
- the discharge valve device 80 of the discharge valve arrangement 70 serves as a check valve, which limits the backflow of the high pressure fuel that is discharged from the pressurizing chamber 12 toward the fuel outlet 72 .
- the plunger 21 In the intake stroke, the plunger 21 is moved downward, so that the volume of the variable volume chamber 30 is decreased. Thus, the fuel of the variable volume chamber 30 is outputted to the damper chamber 40 through the return passage 31 .
- a ratio between the cross-sectional area of the large diameter portion 211 and the cross-sectional area of the variable volume chamber 30 is generally 1:0.6.
- a ratio between the amount of increase in the volume of the pressurizing chamber 12 and the amount of decrease in the volume of the variable volume chamber 30 is generally 1:0.6. Therefore, about 60% of the fuel, which is drawn into the pressurizing chamber 12 , is supplied from the variable volume chamber 30 , and about 40% of the remaining fuel is drawn from the fuel inlet. In this way, an intake efficiency of fuel into the pressurizing chamber 12 is improved.
- the volume of the pressurizing chamber 12 is decreased.
- the energization of the coil 611 is stopped until the predetermined timing (predetermined time point), so that the needle 67 and the intake valve 55 are urged by the urging force of the second spring 68 in the right direction in FIG. 1 and are thereby placed at the right side position in FIG. 1 .
- the supply passage 52 is kept in the open state.
- the low pressure fuel which is once drawn into the pressurizing chamber 12 , is returned to the supply passage 52 .
- the pressure of the pressurizing chamber 12 is not increased.
- the plunger 21 In the metering stroke, the plunger 21 is moved upward, so that the volume of the variable volume chamber 30 is increased. Thus, the fuel of the damper chamber 40 flows into the variable volume chamber 30 through the return passage 31 .
- the coil 611 is energized. Then, a magnetic attractive force is generated between the stationary core 62 and the movable core 63 due to the generation of the magnetic field from the coil 611 .
- this magnetic attractive force becomes larger than a difference between the resilient force of the second spring 68 and the resilient force of the first spring 57 , the movable core 63 and the needle 67 are moved toward the stationary core 62 side (in the left direction in FIG. 1 ). Thereby, the urging force of the needle 67 against the intake valve 55 is released.
- the intake valve 55 is moved toward the seat 54 side by the resilient force of the first spring 57 and the force generated by the flow of the low pressure fuel, which is outputted from the pressurizing chamber 12 toward the damper chamber 40 .
- the intake valve 55 is seated against the seat 54 , so that the supply passage 52 is closed.
- the discharge valve member 82 of the discharge valve device 80 is opened when the force, which is applied to the discharge valve member 82 by the pressure of the fuel on the upstream side of the discharge valve member 82 , becomes larger than a sum of the urging force of the spring 83 and the force, which is applied to the discharge valve member 82 by the pressure of the fuel on the downstream side of the discharge valve member 82 . In this way, the high pressure fuel, which is pressurized in the pressurizing chamber 12 , is discharged from the fuel outlet 72 through the discharge passage 71 .
- the energization of the coil 611 is stopped.
- the force, which is applied to the intake valve 55 from the pressure of the fuel in the pressurizing chamber 12 is larger than the urging force of the second spring 68 , so that the intake valve 55 is kept in the valve closed state.
- the high pressure pump 1 repeats the intake stroke, the metering stroke and the pressurizing stroke, so that the fuel, which is required by the internal combustion engine, is pressurized and is discharged from the high pressure pump 1 .
- the quantity of fuel, which is discharged from the high pressure pump 1 is controlled to the required quantity, which is required by the internal combustion engine, by controlling the timing of energizing the coil 611 .
- the gas chamber 32 is placed at the location adjacent to the variable volume chamber 30 of the high pressure pump 1 .
- the gas chamber 32 is formed by the inner blocking wall 33 placed adjacent to the variable volume chamber 30 , the seal element (serving as the outer blocking wall) 25 and the nitrogen gas 35 sealed in the space 37 between the inner blocking wall 33 and the seal element 25 . Therefore, even when the heat of an engine head, which is heated to the high temperature and is placed adjacent to the cam that drives the plunger to reciprocate the same, is conducted toward the fuel in the variable volume chamber 30 , the influence of the heat from the engine head is blocked or alleviated by the nitrogen gas 35 in the gas chamber 32 , which is placed in the heat conduction path between the engine head and the variable volume chamber 30 .
- the high temperature lubricating oil including engine oil
- the high temperature lubricating oil is scattered from the cam or its adjacent area and is adhered to the outer wall of the seal element 25 to cause conduction of the heat from the adhered high temperature lubricating oil to the fuel in the variable volume chamber 30
- the influence of the heat of the adhered high temperature lubricating oil is blocked or alleviated by the nitrogen gas 35 in the gas chamber 32 , which is placed between the adhered high temperature lubricating oil and the fuel in the variable volume chamber 30 .
- a thermal conductivity of the nitrogen gas 35 in the gas chamber 32 is 25.76 mW/(m ⁇ K) under the temperature of 25 degrees Celsius and the atmospheric pressure of 1 atm.
- This thermal conductivity of the nitrogen gas 35 is much lower than that of the metal material of the high pressure pump 1 and of the other solid materials. Therefore, the nitrogen gas 35 can effectively block or limit the conduction of the heat to the fuel in the variable volume chamber 30 .
- the peripheral wall of the one end portion 331 of the inner blocking wall 33 of the gas chamber 32 is welded to the inner peripheral surface of the seal element 25 at the welding portion 34 a all around the one end portion 331 in the circumferential direction, and the outer peripheral wall of the other end portion 332 of the inner blocking wall 33 is welded to the inner peripheral surface of the seal element 25 at the welding portion 34 b all around the other end portion 332 in the circumferential direction.
- the nitrogen gas 35 in the gas chamber 32 is sealed in the airtight state in the space 37 .
- the heat conduction blocking function (or the heat conducting limiting function) of the nitrogen gas 35 in the gas chamber 32 is stably maintained.
- the increasing of the temperature of the fuel in the variable volume chamber 30 to the high temperature can be limited by the heat conduction blocking function (or the heat conducting limiting function) of the nitrogen gas 35 in the gas chamber 32 , which is adjacent to the variable volume chamber 30 , and thereby the vaporization of the fuel in the variable volume chamber 30 can be limited.
- the occurrence of the operational malfunction of the high pressure pump 1 i.e., the difficulty of drawing the fuel by the high pressure pump 1 caused by the vaporization of the fuel in the variable volume chamber 30 .
- the fuel in the variable volume chamber 30 is outputted to the damper chamber 40 and is then returned to the damper chamber 40 in response to the moving up and moving down of the plunger 21 .
- the inner blocking wall 33 which is resiliently deformable and is interposed between the fuel in the variable volume chamber 30 and the nitrogen gas 35 in the gas chamber 32 , functions as the pulsation damper for the fuel in the variable volume chamber 30 .
- the pressure pulsation of the fuel in the variable volume chamber 30 is reduced or minimized.
- the fuel pressure pulsation reducing effect of the inner blocking wall 33 which functions as the pulsation damper for the fuel in the variable volume chamber 30
- the fuel pressure pulsation reducing effect, which is implemented by the damper chamber 40 can further reduce the pressure pulsation of the low pressure fuel, which is supplied to the pressurizing chamber 12 . Thereby, the appropriate operation of the high pressure pump 1 can be more effectively ensured.
- the one end portion 331 of the inner blocking wall 33 which is the component of the gas chamber 32 , is installed such that the wall surface of the one end portion 331 of the inner blocking wall 33 , which is axially located on the pressurizing chamber 12 side, is axially opposed to the step surface 213 of the plunger 21 , and the wall surface of the one end portion 331 of the inner blocking wall 33 , which is axially located on the side opposite from the pressurizing chamber 12 , contacts the other end portion of the seal member 24 , which is axially located on the pressurizing chamber 12 side. Therefore, the inner blocking wall 33 functions as the stopper of the plunger 21 at the time of reciprocating the plunger 21 in the cylinder hole 11 .
- the inner blocking wall 33 cooperates with the seal element 25 , which contacts both of the one end portion of the seal member 24 axially located on the spring seat 27 side and the outer peripheral portion of the seal member 24 radially located on the side opposite from the small diameter portion 212 , to function as the holder, which securely holds, i.e., axially clamps the seal member 24 .
- the inner blocking wall 33 of the gas chamber 32 has the function, which is previously implemented in a plunger stopper in a previously proposed high pressure pump. Therefore, the plunger stopper, which is used in the previously proposed high pressure pump, is not required in the high pressure pump 1 of the present embodiment. Thus, the number of the components of the high pressure pump 1 can be reduced, and thereby the manufacturing costs of the high pressure pump 1 can be reduced.
- the seal element 25 which is also employed in the previously proposed high pressure pump, is used as the outer blocking wall of the gas chamber 32 , so that it is possible to limit an increase in the number of components, which are required to form the gas chamber 32 . Therefore, it is possible to limit an increase in the manufacturing costs of the high pressure pump 1 .
- FIG. 3 shows a plunger arrangement of a high pressure pump according to a second embodiment of the present invention.
- components which are similar to those of the first embodiment, will be indicated by the same reference numerals and will not be redundantly described.
- the plunger arrangement 20 of the high pressure pump 2 of the present embodiment will be described with referent o FIG. 3 .
- the other remaining structure of the high pressure pump 2 of the present embodiment, which is other than the plunger arrangement 20 is the same as that of the high pressure pump 1 of the first embodiment shown in FIG. 1 and thereby will not be described further.
- the plunger arrangement 20 includes the plunger 21 , the seal member 24 , the seal element 25 , the plunger spring 28 and the variable volume chamber 30 .
- a gas chamber 32 A which is adjacent to the variable volume chamber 30 of the high pressure pump 2 , includes an inner blocking wall 33 A in place of the inner blocking wall 33 of the first embodiment. Similar to the first embodiment, the inner blocking wall 33 A is the resiliently deformable member and functions as the pulsation damper for the fuel in the variable volume chamber 30 .
- one end portion 331 a of the inner blocking wall 33 A which is axially located on the side opposite from the damper chamber 40 , extends in the direction generally perpendicular to the central axis of the cylinder hole 11 . Furthermore, a peripheral wall of the one end portion 331 a of the inner blocking wall 33 A is welded to the inner peripheral surface of the seal element 25 at the welding portion 34 a all around the one end portion 331 a in the circumferential direction like in the first embodiment. Unlike the first embodiment, the other end portion 332 a of the inner blocking wall 33 A, which is axially located on the damper chamber 40 side, extends in a direction generally perpendicular to the central axis of the cylinder hole 11 .
- a peripheral wall of the other end portion 332 a of the inner blocking wall 33 A is welded to the inner peripheral surface of the seal element 25 at a welding portion 34 c , which is different from the welding portion 34 b of the first embodiment, all around the other end portion 332 a in the circumferential direction.
- the nitrogen gas 35 is filled into and is sealed in the space 37 , which is defined between the inner blocking wall 33 A and the seal element (serving as the outer blocking wall) 25 .
- the inner blocking wall 33 A which is configured into the shape that is different from the inner blocking wall 33 of the first embodiment, the seal element (serving as the outer blocking wall) 25 and the nitrogen gas 35 airtightly sealed in the space 37 between the inner blocking wall 33 A and the seal element 25 form the gas chamber 32 A of the present embodiment.
- the one end portion 331 a of the inner blocking wall 33 A which is the component of the gas chamber 32 A, is installed such that the wall surface of the one end portion 331 a of the inner blocking wall 33 A, which is axially located on the pressurizing chamber 12 side, is axially opposed to the step surface 213 of the plunger 21 , and the wall surface of the one end portion 331 a of the inner blocking wall 33 A, which is axially located on the side opposite from the pressurizing chamber 12 , contacts the other end portion of the seal member 24 , which is axially located on the pressurizing chamber 12 side. Therefore, similar to the first embodiment, the inner blocking wall 33 A has the function similar to that of the plunger stopper of the previously proposed high pressure pump.
- the other remaining structure of the plunger arrangement 20 of the present embodiment which is other than the gas chamber 32 A, is the same as that of the first embodiment and thereby will not be described further.
- the gas chamber 32 which is placed adjacent to the variable volume chamber 30 of the high pressure pump 2 , is formed by the inner blocking wall 33 A placed adjacent to the variable volume chamber 30 , the seal element (serving as the outer blocking wall) 25 and the nitrogen gas 35 sealed in the space 37 between the inner blocking wall 33 and the seal element 25 .
- the increasing of the temperature of the fuel in the variable volume chamber 30 to the high temperature can be limited by the heat conduction blocking function (or the heat conducting limiting function) of the nitrogen gas 35 in the gas chamber 32 A, and thereby the vaporization of the fuel in the variable volume chamber 30 can be limited.
- the heat conduction blocking function or the heat conducting limiting function
- the shape of the inner blocking wall 33 A of the gas chamber 32 A and the welding portion 34 c of the inner blocking wall 33 A, which is welded to the seal element 25 are different from the shape of the inner blocking wall 33 of the gas chamber 32 and the welding portion 34 b of the inner blocking wall 33 , which is welded to the seal element 25 , of the first embodiment.
- the other end portion 332 of the inner blocking wall 33 of the gas chamber 32 extends in the direction generally parallel to the central axis of the cylinder hole 11 , and the peripheral wall of the other end portion 332 of the inner blocking wall 33 is welded to the inner peripheral surface of the seal element 25 at the welding portion 34 b all around the other end portion 332 in the circumferential direction.
- the other end portion 332 a of the inner blocking wall 33 A of the gas chamber 32 A extends in the direction generally perpendicular to the central axis of the cylinder hole 11 , and the peripheral wall of the other end portion 332 a of the inner blocking wall 33 A is welded to the inner peripheral surface of the seal element 25 at the welding portion 34 c all around the other end portion 332 a in the circumferential direction.
- the volume of the gas chamber 32 A (more specifically, the volume of the space 37 ) is increased in comparison to the volume of the gas chamber 32 of the first embodiment, as evident from FIGS. 2 and 3 .
- the volume of the nitrogen gas 35 which is sealed in the gas chamber 32 A is increased in comparison to the volume of the nitrogen gas 35 , which is sealed in the gas chamber 32 of the first embodiment.
- the heat conduction blocking function (or the heat conducting limiting function) of the nitrogen gas 35 in the gas chamber 32 A is further enhanced in the second embodiment in comparison to the first embodiment.
- the other advantages of the present embodiment are similar to those of the first embodiment. These other advantages of the present embodiment include, for example, the reduction of the pressure pulsation of the low pressure fuel supplied to the pressurizing chamber 12 implemented by the fuel pressure pulsation reducing effect of the inner blocking wall 33 A, which serves as the pulsation damper for the fuel in the variable volume chamber 30 .
- FIG. 4 shows a plunger arrangement of a high pressure pump according to a third embodiment of the present invention.
- the plunger arrangement 20 of the high pressure pump 3 of the present embodiment will be described with referent o FIG. 4 .
- the other remaining structure of the high pressure pump 2 of the present embodiment, which is other than the plunger arrangement 20 is the same as that of the high pressure pump 1 of the first embodiment shown in FIG. 1 and thereby will not be described further.
- the plunger arrangement 20 includes the plunger 21 , the seal member 24 , the seal element 25 , the plunger spring 28 and the variable volume chamber 30 .
- the plunger arrangement 20 of the present embodiment includes a plunger stopper 23 .
- the plunger stopper 23 is configured into an annular form and surrounds the small diameter portion 212 of the plunger 21 .
- An end surface of the plunger stopper 23 which is axially located on the pressurizing chamber 12 side, is axially recessed toward the spring seat 27 side to form a recess.
- An end surface 231 of the plunger stopper 23 which is radially located on the outer side of the recess and is axially directed to the pressurizing chamber 12 side (i.e., is axially located on the pressurizing chamber 12 side), is joined to or securely connected to the pump body 10 .
- An end surface 232 of the recess of the plunger stopper 23 which is directed to the pressurizing chamber 12 side (i.e., is axially located on the pressurizing chamber 12 side), is axially opposed to the step surface 213 , which is formed between the large diameter portion 211 and the small diameter portion 212 of the plunger 21 .
- the end surface 232 of the plunger stopper 23 which is axially opposed to the step surface 213 of the plunger 21 , functions as the stopper, which is adapted to abut against the step surface 213 of the plunger 21 and thereby to limit the reciprocating movement of the plunger 21 in the cylinder hole 11 , particularly the downward movement of the plunger 21 in the cylinder hole 11 in a direction away from the top dead center toward the bottom dead center.
- a plurality of groove passages (only one is shown in FIG. 4 ) 23 a which serve as radial passages, is formed in the plunger stopper 23 to radially extend from the interior of the recess to the outer peripheral edge of the plunger stopper 23 to enable fluid communication therebetween.
- the groove passages 23 a of the plunger stopper 23 communicate between one area (radially inner area) of the variable volume chamber 30 , which is defined between the step surface 213 of the plunger 21 and the plunger stopper 23 upon lifting of the step surface 213 of the plunger 21 from the end surface 232 of the plunger stopper 23 , to another area (radially outer area) of the variable volume chamber 30 , which is communicated with the damper chamber 40 .
- the seal member 24 is installed around the small diameter portion 212 of the plunger 21 at an axial location, which is on the spring seat 27 side of the plunger stopper 23 , such that the seal member 24 surrounds the small diameter portion 212 in the circumferential direction.
- the other end portion of the seal member 24 which is axially located on the pressurizing chamber 12 side, contacts a wall surface of the plunger stopper 23 , which is axially located on the spring seat 27 side.
- the plunger stopper 23 cooperates with the seal element 25 , which contacts both of the one end portion of the seal member 24 axially located on the spring seat 27 side and the radially outer portion of the seal member 24 radially located on the side opposite from the small diameter portion, to function as the holder, which securely holds, i.e., axially clamps the seal member 24 .
- the seal element 25 , the plunger spring 28 and the variable volume chamber 30 are arranged in a manner similar to that of the first embodiment.
- a gas chamber 32 B which is adjacent to the variable volume chamber 30 of the high pressure pump 3 , includes an inner blocking wall 33 B in place of the inner blocking wall 33 of the first embodiment. Similar to the first embodiment, the inner blocking wall 33 B is the resiliently deformable member and functions as the pulsation damper for the fuel in the variable volume chamber 30 .
- one end portion 331 b of the inner blocking wall 33 B which is axially located on the side opposite from the damper chamber 40 , extends in a direction generally parallel to the central axis of the cylinder hole 11 . Furthermore, a peripheral wall of the one end portion 331 b of the inner blocking wall 33 B is welded to the inner peripheral surface of the seal element 25 at the welding portion 34 a all around the one end portion 331 b in the circumferential direction like in the first embodiment.
- the shape of the one end portion 331 b of the inner blocking wall 33 B is different from that of the first embodiment.
- the peripheral wall of the one end portion 331 b of the inner blocking wall 33 B contacts an outer peripheral wall of the plunger stopper 23 .
- the other end portion 332 b of the inner blocking wall 33 B which is axially located on the damper chamber 40 side, extends in the direction generally parallel to the central axis of the cylinder hole 11 .
- a peripheral wall of the other end portion 332 b of the inner blocking wall 33 B is welded to the inner peripheral surface of the seal element 25 at the welding portion 34 b all around the other end portion 332 b in the circumferential direction, like in the first embodiment.
- the nitrogen gas 35 is sealed into the space 37 , which is held between the inner blocking wall 33 B and the seal element (serving as the outer blocking wall) 25 .
- the inner blocking wall 33 B, the seal element (serving as the outer blocking wall) 25 and the nitrogen gas 35 airtightly sealed therebetween form the gas chamber 32 B of the present embodiment.
- the gas chamber 32 B which is placed adjacent to the variable volume chamber 30 of the high pressure pump 3 , is formed by the inner blocking wall 33 B placed adjacent to the variable volume chamber 30 , the seal element (serving as the outer blocking wall) 25 and the nitrogen gas 35 sealed in the space 37 between the inner blocking wall 33 B and the seal element 25 . Therefore, similar to the first embodiment, the increasing of the temperature of the fuel in the variable volume chamber 30 to the high temperature can be limited by the heat conduction blocking function (or the heat conducting limiting function) of the nitrogen gas 35 in the gas chamber 32 B, and thereby the vaporization of the fuel in the variable volume chamber 30 can be limited. Thus, it is possible to limit the occurrence of the operational malfunction of the high pressure pump 3 caused by the vaporization of the fuel in the variable volume chamber 30 .
- the inner blocking wall 33 B of the gas chamber 32 B which is resiliently deformable, functions as the pulsation damper to reduce or minimize the fuel pressure pulsation of the fuel in the variable volume chamber 30 . Therefore, it contributes to the reduction or minimization of the pressure pulsation of the low pressure fuel, which is supplied to the pressurizing chamber 12 .
- the plunger stopper 23 is provided.
- the plunger stopper 23 functions as the stopper for the reciprocating movement of the plunger 21 .
- the plunger stopper 23 cooperates with the seal element 25 to function as the holder, which securely holds, i.e., axially clamps the seal member 24 . Therefore, the functions, which are implemented by the inner blocking wall 33 of the first embodiment, are not implemented by the inner blocking wall 33 B of the present embodiment.
- the advantages similar to those of the first embodiment can be achieved by providing the gas chamber 32 B, which is formed by the inner blocking wall 33 B, which is placed adjacent to the variable volume chamber 30 and functions as the pulsation damper, the seal element (serving as the outer blocking wall) 25 and the nitrogen gas 35 sealed in the space 37 formed between the inner blocking wall 33 and the seal element 25 .
- FIG. 5 shows a plunger arrangement of a high pressure pump according to a fourth embodiment of the present invention.
- the plunger arrangement 20 of the high pressure pump 4 of the present embodiment will be described with referent o FIG. 5 .
- the other remaining structure of the high pressure pump 4 of the present embodiment, which is other than the plunger arrangement 20 is the same as that of the high pressure pump 1 of the first embodiment shown in FIG. 1 and thereby will not be described further.
- the plunger arrangement 20 includes the plunger 21 , the plunger stopper 23 , the seal member 24 , the seal element 25 , the plunger spring 28 and the variable volume chamber 30 .
- a gas chamber 32 C which is placed adjacent to the variable volume chamber 30 of the high pressure pump 4 of the present embodiment, includes the seal element 25 , which now serves as the inner blocking wall, in place of the inner blocking wall 33 B of the third embodiment.
- the gas chamber 32 C further includes an outer blocking wall 36 in place of the seal element 25 , which serves as the outer blocking wall in the third embodiment.
- the outer blocking wall 36 is made of a heat insulation member.
- One end portion 361 of the outer blocking wall 36 which is located on the side opposite from the damper chamber 40 , extends in a direction that is generally parallel to the central axis of the cylinder hole 11 .
- the other end portion 362 of the outer blocking wall 36 which is located on the side where the damper chamber 40 is located, extends in a direction generally perpendicular to the central axis of the cylinder hole 11 .
- a peripheral wall of the one end portion 361 of the outer blocking wall 36 is welded to the inner peripheral surface of the seal element 25 at a welding portion 34 d all around the one end portion 361 in the circumferential direction.
- An outer peripheral wall of the other end portion 362 of the outer blocking wall 36 is welded to the inner peripheral surface of the seal element 25 at a welding portion 34 e all around the other end portion 362 in the circumferential direction.
- the nitrogen gas 35 is sealed into the space 37 , which is held between the seal element (serving as the inner blocking wall) 25 and the outer blocking wall 36 .
- the gas chamber 32 C of the present embodiment is formed by the seal element (serving as the inner blocking wall) 25 , the outer blocking wall 36 and the nitrogen gas 35 sealed in the space 37 formed between the seal element 25 and the outer blocking wall 36 .
- the other remaining structure of the high pressure pump 4 of the present embodiment which is other than the gas chamber 32 C of the plunger arrangement 20 , is the same as that of the high pressure pump 3 of the third embodiment and thereby will not be described further.
- the gas chamber 32 C which is placed adjacent to the variable volume chamber 30 of the high pressure pump 4 , is made by the seal element (serving as the inner blocking wall) 25 , the outer blocking wall 36 made of the heat insulation member, and the nitrogen gas 35 sealed in the space 37 formed between the seal element 25 and the outer blocking wall 36 .
- the heat conduction blocking function (or the heat conduction limiting function) can be implemented by the nitrogen gas 35 in the gas chamber 32 C, and thereby it is possible to limit the occurrence of the operational malfunction of the high pressure pump 4 caused by the vaporization of the fuel in the variable volume chamber 30 .
- the outer blocking wall 36 is made of the heat insulation member. Therefore, the heat conduction blocking function (or the heat conduction limiting function) of the outer blocking wall 36 is implemented in addition to the heat conduction blocking function (or the heat conduction limiting function) of nitrogen gas 35 . As a result, the heat conduction blocking function of the entire gas chamber 32 C is further increased, and thereby the operational malfunction of the high pressure pump 4 can be more effectively limited.
- the nitrogen gas 35 is used as the gas, which is sealed in the space 37 of the gas chamber 32 , 32 A, 32 B, 32 C.
- the gas, which is sealed in the space 37 of the gas chamber 32 , 32 A, 32 B, 32 C is not limited to the nitrogen gas.
- helium gas, argon gas or air can be used as the gas sealed in the space 37 of the gas chamber 32 , 32 A, 32 B, 32 C in place of the nitrogen gas.
- Each of these gases has the thermal conductivity much lower than the metal material of the high pressure pump 1 , 2 , 3 , 4 or the other solid material(s).
- the space 37 may possibly be left as an open space unlike the first to fourth embodiments, in which the space 37 is formed as the closed space.
- the one end portion 361 of the outer blocking wall 36 may be spaced from the seal element 25 or may be engaged with the seal element 25 without entirely welding therebetween in the circumferential direction in a manner that enables the fluid communication between the space 37 and the outside space located outside of the outer blocking wall 36 . Therefore, at the time of connecting and securing the inner blocking wall 33 , 33 A, 33 B or the outer blocking wall 36 to the seal element 25 , it is possible to use any other method, which is other than the welding-all-around the seal element 25 .
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Fuel-Injection Apparatus (AREA)
Abstract
Description
- This application is based on and incorporates herein by reference Japanese Patent Application No. 2011-15643 filed on Jan. 27, 2011.
- 1. Field of the Invention
- The present invention relates to a high pressure pump.
- 2. Description of Related Art
- A high pressure pump, which supplies fuel to a fuel supply system of an internal combustion engine, is known. Fuel, which is drawn out of a fuel tank, is drawn into a pressurizing chamber upon downward movement of a plunger in a cylinder hole of the high pressure pump and is metered upon upward movement of the plunger in the cylinder hole.
- Furthermore, it is known to provide a mechanism, which reduces pressure pulsation of low pressure fuel, in the previously known high pressure pump.
- For instance, in a high pressure pump recited in DE102004063075A1, a damper chamber (pressure dumper) and a variable volume chamber (compensation chamber) are provided as a fuel pressure pulsation reducing mechanism.
- However, in the high pressure pump of DE102004063075A1, the variable volume chamber (the compensation chamber) is covered by only a portion (sleeve part) of a seal element (stop element). Therefore, the fuel in the variable volume chamber may be heated by heat, which is conducted from a heated engine head located adjacent to a cam that reciprocates a plunger. Also, the fuel in the variable volume chamber may be heated by lubricating oil (including engine oil), which is initially applied to the cam or therearound and is dispersed over the seal element. When the fuel in the variable volume chamber is heated to the high temperature in this way, the fuel may possibly be vaporized. When the fuel in the variable volume chamber is vaporized, the high pressure pump may have a difficulty of drawing fuel, so that the operational malfunction of the high pressure pump may occur.
- The present invention addresses the above disadvantages.
- According to the present invention, there is provided a high pressure pump, which includes a plunger, a pump body, variable volume chamber forming means and a gas chamber. The pump body includes a cylinder hole, a pressurizing chamber, a low pressure fuel passage and a discharge passage. The plunger is adapted to reciprocate in an axial direction thereof in the cylinder hole. The pressurizing chamber is communicated with the cylinder hole, and fuel is pressurized in the pressurizing chamber by reciprocating movement of the plunger. The low pressure fuel passage communicates between the pressurizing chamber and a fuel inlet. The discharge passage communicates between the pressurizing chamber and a fuel outlet. The variable volume chamber forming means is for forming a variable volume chamber, a volume of which changes by the reciprocating movement of the plunger. The variable volume chamber is placed adjacent to a step surface of the plunger. The step surface of the plunger is located between a large diameter portion of the plunger, which has an end portion exposed to the pressurizing chamber and is slidable along an inner peripheral wall surface of the cylinder hole, and a small diameter portion of the plunger, which extend from the large diameter portion in the axial direction on a side opposite from the pressurizing chamber. The gas chamber is placed adjacent to the variable volume chamber on a side of the variable volume chamber, which is opposite from the cylinder hole.
- The gas chamber may be formed in a recess of the pump body, which is configured into a generally annular form around the cylinder hole on a radially outer side of the cylinder hole. The gas chamber may include or may be formed at least by an inner blocking wall, an outer blocking wall and gas. The inner blocking wall borders on the variable volume chamber and contacts fuel in the variable volume chamber. The outer blocking wall is opposed to the inner blocking wall. The gas fills a space that is defined between the inner blocking wall and the outer blocking wall, and this space may be an open space or closed space. A seal member may be installed to the small diameter portion of the plunger to surround the small diameter portion in a circumferential direction. The variable volume chamber forming means may include at least one or all of the step surface of the plunger, an outer peripheral wall of the small diameter portion, the inner peripheral wall of the cylinder hole of the pump body, an end portion of the seal member, a wall surface of the inner blocking wall and a wall surface of the recess of the pump body.
- The invention, together with additional objectives, features and advantages thereof, will be best understood from the following description, the appended claims and the accompanying drawings in which:
-
FIG. 1 is a schematic longitudinal cross sectional view of a high pressure pump according to a first embodiment of the present invention; -
FIG. 2 is an enlarged schematic cross-sectional view showing a plunger arrangement of the high pressure pump shown inFIG. 1 ; -
FIG. 3 is an enlarged schematic cross-sectional view showing a plunger arrangement of a high pressure pump according to a second embodiment of the present invention; -
FIG. 4 is an enlarged schematic cross-sectional view showing a plunger arrangement of a high pressure pump according to a third embodiment of the present invention; and -
FIG. 5 is an enlarged schematic cross-sectional view showing a plunger arrangement of a high pressure pump according to a fourth embodiment of the present invention. - Various embodiments of the present invention will be described with reference to the accompanying drawings.
-
FIG. 1 shows a high pressure pump according to a first embodiment of the present invention.FIG. 2 shows a plunger arrangement of the high pressure pump. - The
high pressure pump 1 of the present embodiment will be described with reference toFIG. 1 . - The
high pressure pump 1 is provided in a fuel supply system, which supplies fuel to an internal combustion engine of a vehicle (e.g., an automobile). The fuel, which is drawn from a fuel tank, is pressurized by thehigh pressure pump 1 and is stored in a delivery pipe. The fuel is injected from each corresponding injector, which is connected to the delivery pipe, into a corresponding cylinder of the internal combustion engine. - The
high pressure pump 1 includes apump body 10, aplunger arrangement 20, adamper chamber 40, anintake valve arrangement 50, anelectromagnetic drive arrangement 60 and adischarge valve arrangement 70. - (a) The
pump body 10 and theplunger arrangement 20 will be described. - The
pump body 10 has acylinder hole 11 and a pressurizingchamber 12, which are communicated with each other and are formed integrally in thepump body 10. Arecess 13, which is configured into a generally annular form, is formed around thecylinder hole 11 on a radially outer side of thecylinder hole 11, and a cylindricaltubular protrusion 10 a of thepump body 10, which is axially downwardly protrudes inFIG. 2 , is radially interposed between thecylinder hole 11 and a space of therecess 13 located radially outward of the cylindricaltubular portion 10 a. Therefore, a lower end portion of thecylinder hole 11 is formed by the cylindricaltubular protrusion 10 a of thepump body 10. - The
plunger arrangement 20 includes aplunger 21, aseal member 24, aseal element 25, aplunger spring 28 and avariable volume chamber 30. - The
plunger 21 is received in thecylinder hole 11 such that theplunger 21 is adapted to be axially reciprocated in an axial direction of theplunger 21 in thecylinder hole 11. Theplunger 21 has alarge diameter portion 211 and asmall diameter portion 212. One end portion of thelarge diameter portion 211 is connected thesmall diameter portion 212, and the other end portion of thelarge diameter portion 211 is exposed to the pressurizingchamber 12. Thelarge diameter portion 211 is slidable along an inner peripheral wall of thecylinder hole 11. Thesmall diameter portion 212 has an outer diameter smaller than that of thelarge diameter portion 211 and axially extends from thelarge diameter portion 211 on a side, which is axially opposite from the pressurizingchamber 12. Thelarge diameter portion 211 and thesmall diameter portion 212 are coaxial with each other, and astep surface 213 is formed between thelarge diameter portion 211 and thesmall diameter portion 212. Aspring seat 27 is installed to oneend portion 22 of thesmall diameter portion 212, which is opposite from thelarge diameter portion 211. - The
seal member 24 is installed around thesmall diameter portion 212 of theplunger 21 such that theseal member 24 surrounds thesmall diameter portion 212 in a circumferential direction on a radially outer side of thesmall diameter portion 212. Theseal member 24 includes a ring (Teflon ring, the name “Teflon” being a registered trademark of DuPont for its brand of fluoropolymer resins) and an O-ring. The ring is placed on a radially inner side and slidably contacts an outer peripheral surface of thesmall diameter portion 212, and the O-ring is placed on a radially outer side of the ring. Theseal member 24 limits a thickness of a fuel film, which is formed around thesmall diameter portion 212, and also limits leakage of fuel toward the engine caused by the slide movement of theplunger 21. - The
seal element 25 is installed around a portion of thesmall diameter portion 212, which is located on thespring seat 27 side of theseal member 24, such that theseal element 25 surrounds thesmall diameter portion 212 in the circumferential direction on the radially outer side of thesmall diameter portion 212. Theseal element 25 is configured into a generally annular form. A portion of theseal element 25 is installed to and is secured to therecess 13 of thepump body 10. Another portion of theseal element 25 contacts both of one end portion of theseal member 24, which is axially located on thespring seat 27 side, and a radially outer end portion of theseal member 24, i.e., an outer peripheral portion of theseal member 24, which is radially located on the side opposite from thesmall diameter portion 212. In this way, theseal element 25 serves as a holder, which securely holds theseal member 24. - An
oil seal 26 is installed to one end portion of theseal element 25, which is axially located on thespring seat 27 side. Theoil seal 26 surrounds thesmall diameter portion 212 in the circumferential direction. Theoil seal 26 slidably contacts an outer peripheral surface of thesmall diameter portion 212. Theoil seal 26 limits a thickness of an oil film, which is formed around thesmall diameter portion 212, and limits leakage of the oil caused by the slide movement of theplunger 21. - The
spring seat 27 is securely held by thelower end portion 22 of theplunger 21. One end portion of theplunger spring 28 is engaged to thespring seat 27. The other end portion of theplunger spring 28 is engaged to a predetermined end surface of theseat element 25, which is fixed to thepump body 10. Thereby, theseal element 25 also functions as an engaging member of theplunger spring 28. - The
plunger spring 28, which is engaged to theseal element 25 and thespring seat 27 at the opposite ends, respectively, of theplunger spring 28, functions as a return spring of theplunger 21 to urge theplunger 21 against a tapped (not shown). Theplunger 21 is urged against the cam of the camshaft through the tappet by the returning spring function of theplunger spring 28, i.e., the urging force of theplunger spring 28, so that theplunger 21 is axially reciprocated in thecylinder hole 11 upon the rotation of the camshaft. The volume of the pressurizingchamber 12 is changed by the reciprocating movement of theplunger 21, so that the fuel is drawn into and pressurized in the pressurizingchamber 12. - The
variable volume chamber 30 is formed by a generally annular space, which is bounded by thestep surface 213 of theplunger 21, the outer peripheral wall of thesmall diameter portion 212, the inner peripheral wall of thecylinder hole 11 of thepump body 10, a wall surface of the recess 13 (including an outer peripheral wall surface of the cylindricaltubular protrusion 10 a of the pump body 10), and the other end portion of theseal member 24 axially located on the pressurizingchamber 12 side. Thevariable volume chamber 30, which is configured into the generally annular form, surrounds thecylinder hole 11. Thevariable volume chamber 30 is in fluid communication with thedamper chamber 40 through areturn passage 31, which is formed in thepump body 10. - A
gas chamber 32 is located adjacent to thevariable volume chamber 30. Thegas chamber 32 includes aninner blocking wall 33, which is located adjacent to thevariable volume chamber 30. Theinner blocking wall 33 is made of a resiliently deformable member. Oneend portion 331 of theinner blocking wall 33, which is axially located on the side opposite from thedamper chamber 40, extends in a direction generally perpendicular to the central axis of thecylinder hole 11. Furthermore, theother end portion 332 of theinner blocking wall 33, which is axially located on thedamper chamber 40 side, extends in a direction generally parallel to the central axis of thecylinder hole 11. A peripheral wall of the oneend portion 331 of theinner blocking wall 33 is welded to an inner peripheral surface of theseal element 25 at awelding portion 34 a all around the oneend portion 331 in the circumferential direction (i.e., by the welding-all-around). An outer peripheral wall of theother end portion 332 of theinner blocking wall 33 is welded to the inner peripheral surface of theseal element 25 at awelding portion 34 b all around theother end portion 332 in the circumferential direction. - A
space 37, which is defined between theinner blocking wall 33 and theseal element 25, is filled withnitrogen gas 35 and is airtightly sealed, so that thespace 37 is a closed space filled with thenitrogen gas 35. - The
inner blocking wall 33, the seal element (serving as an outer blocking wall) 25 and thenitrogen gas 35 airtightly sealed in thespace 37 therebetween form thegas chamber 32. - A wall surface of the one
end portion 331 of theinner blocking wall 33, which is axially located on the pressurizingchamber 12 side, is axially opposed to thestep surface 213 of theplunger 21. Therefore, the oneend portion 331 of theinner blocking wall 33 functions as a stopper, which limits the reciprocating movement of theplunger 21 in thecylinder hole 11, particularly the downward movement of theplunger 21 in thecylinder hole 11 from the top dead center toward the bottom dead center thereof. - Furthermore, another wall surface of the one
end portion 331 of theinner blocking wall 33, which is axially located on thespring seat 27 side, contacts the other end portion of theseal member 24, which is located on the pressurizingchamber 12 side. Therefore, the oneend portion 331 of theinner blocking wall 33 functions as a holder, which securely holds theseal member 24. Specifically, theinner blocking wall 33, which contacts the other end portion of theseal member 24 axially located on the pressurizingchamber 12 side, cooperates with theseal element 25, which contacts both of the one end portion of theseal member 24 axially located on thespring seat 27 side and the outer peripheral portion of theseal member 24 radially located on the side opposite from thesmall diameter portion 212, to function as the holder, which securely holds, i.e., axially clamps theseal member 24. - (b) Next, the
damper chamber 40 will be described. - The
damper chamber 40 is formed by arecess 41, acover 42 and adamper unit 43. - The other end portion of the
pump body 10, which is axially opposite from thecylinder hole 11, is axially recessed toward thecylinder hole 11 side to form therecess 41. Thecover 42, which is configured into a cup form (a tubular body having a bottom), is installed to thepump body 10 to cover therecess 41 and thereby to seal an inside of therecess 41 from an external atmosphere. - The
damper unit 43 is placed in thedamper chamber 40. Thedamper unit 43 includes apulsation damper 44, a bottomside support portion 45 and a coverside support portion 46. Thepulsation damper 44 includes twometal diaphragms side support portion 45 is placed at a bottom portion of therecess 41. The coverside support portion 46 is placed at thecover 42 side. - In the
pulsation damper 44, gas of a predetermined pressure is sealed in an inside space, which is defined between themetal diaphragm 441 and themetal diaphragm 442. When themetal diaphragms damper chamber 40, pressure pulsation of the fuel in thedamper chamber 40 is damped (limited or alleviated). - A
recess 47, which is configured to correspond with the bottomside support portion 45, is formed in the bottom portion of therecess 41 of thedamper chamber 40. The bottomside support portion 45 is positioned by therecess 47. An opening of an inlet (not shown) is formed in therecess 47, so that the fuel, which is supplied from the low pressure pump, is supplied to a radially inner region of the bottomside support portion 45 through the inlet. Specifically, the fuel of the fuel tank is supplied to thedamper chamber 40 from the fuel inlet through the fuel passage. - A
wavy spring 48 is placed on the upper side of the coverside support portion 46. Therefore, in the installed state where thecover 42 is installed to thepump body 10, thewavy spring 48 urges the coverside support portion 46 toward the bottomside support portion 45. Thus, thepulsation damper 44 is secured such that thepulsation damper 44 is clamped between the coverside support portion 46 and the bottomside support portion 45 by a generally uniform clamping force, which is generally uniform along the entire circumference of thepulsation damper 44 and is applied from the coverside support portion 46 and the bottomside support portion 45. - (c) The
intake valve arrangement 50 will now be described. - The
intake valve arrangement 50 includes asupply passage 52, avalve body 53, aseat 54 and anintake valve 55. - The
pump body 10 has atubular portion 51, which extends in a direction that is generally perpendicular to the central axis of thecylinder hole 11. Thesupply passage 52 is formed in an inside of thetubular portion 51. Thevalve body 53 is received in thetubular portion 51 and is fixed by an engaging member. Theseat 54 is formed in the inside of thevalve body 53 such that theseat 54 has a tapered inner peripheral concave surface. Theintake valve 55 is placed such that theintake valve 55 is opposed to theseat 54. Theintake valve 55 is reciprocated such that theintake valve 55 is guided by an inner peripheral wall of a hole, which is formed in a bottom portion of thevalve body 53. When theintake valve 55 is lifted from theseat 54, thesupply passage 52 is opened. In contrast, when theintake valve 55 is seated against theseat 54, thesupply passage 52 is closed with theintake valve 55. - A
stopper 56 is fixed to an inner peripheral wall of thevalve body 53 such that thestopper 56 limits movement of the intake valve in a valve opening direction (the right direction inFIG. 1 ) of theintake valve 55. A first spring 57 is placed between an inner portion of thestopper 56 and an end surface of theintake valve 55. The first spring 57 urges theintake valve 55 in a valve closing direction (the left direction in FIG. 1). - A plurality of tilted
passages 58 is formed in thestopper 56 such that the tiltedpassages 58 are tilted relative to the axis of thestopper 56 and are arranged one after another in a circumferential direction. The fuel, which is supplied through thesupply passage 52, is drawn into the pressurizingchamber 12 through the tiltedpassages 58. Furthermore, thesupply passage 52 is communicated with thedamper chamber 40 through a pressurizingside passage 59. Thereby, thedamper chamber 40, the pressurizingside passage 59, thesupply passage 52 and the tiltedpassages 58 cooperate together to form a low pressure fuel passage, which communicates between the inlet and the pressurizingchamber 12. - (d) The
electromagnetic drive arrangement 60 will be described. - The
electromagnetic drive arrangement 60 includes aconnector 61, astationary core 62, amovable core 63 and aflange 64. - The
connector 61 includes acoil 611 andterminals 612. When an electric power is supplied to thecoil 611 through theterminals 612, a magnetic field is generated from thecoil 611. Thestationary core 62 is made of a magnetic material and is received in the inside of thecoil 611. Themovable core 63 is made of a magnetic material and is opposed to thestationary core 62. Themovable core 63 is adapted to axially reciprocate at a location radially inward of theflange 64. - The
flange 64 is made of a magnetic material and is installed to thetubular portion 51 of thepump body 10. Theflange 64 holds theconnector 61 in corporation with thepump body 10 and closes an end portion of thetubular portion 51. Aguide tube 65 is installed to an inner peripheral wall of a hole, which is formed in a center of theflange 64. Atubular member 66, which is made of a non-magnetic material, limits magnetic short circuit between thestationary core 62 and theflange 64. - A
needle 67 is configured into a generally cylindrical tubular form and is guided by an inner peripheral wall of theguide tube 65 such that theneedle 67 is adapted to be reciprocated along the inner peripheral wall of theguide tube 65. One end portion of theneedle 67 is fixed to themovable core 63, and the other end portion of theneedle 67 is contactable with an end surface of theintake valve 55, which is located on a side where theelectromagnetic drive arrangement 60 is located. - A
second spring 68 is placed between thestationary core 62 and themovable core 63. Thesecond spring 68 urges themovable core 63 in the valve opening direction by an urging force, which is larger than an urging force of the first spring 57, which urges theintake valve 55 in the valve closing direction. - When the
coil 611 is not energized, themovable core 63 and thestationary core 62 are spaced from each other by a resilient force of thesecond spring 68. Thereby, theneedle 67, which is integrated with themovable core 63, is moved toward theintake valve 55 side to urge theintake valve 55 with the end surface of theneedle 67, so that theintake valve 55 is opened. - (e) The
discharge valve arrangement 70 will be described. - The
discharge valve arrangement 70 includes adischarge passage 71 and adischarge valve device 80. - The
discharge passage 71 is formed in thepump body 10 such that thedischarge passage 71 extends in a direction that is generally perpendicular to the central axis of thecylinder hole 11. One end of thedischarge passage 71 is communicated with the pressurizingchamber 12, and the other end of thedischarge passage 71 is communicated with afuel outlet 72. Thedischarge valve device 80 is installed to thedischarge passage 71. - The
discharge valve device 80 includes adischarge valve member 82, aspring 83 and an adjustingpipe 84. - The
discharge valve member 82 is received in thepump body 10 such that thedischarge valve member 82 is opposed to avalve seat 85 of thepump body 10. - The
spring 83, which serves as an urging member, is received in thepump body 10 on afuel outlet 72 side of thedischarge valve member 82. One end portion of thespring 83 contacts an end surface (a right end surface inFIG. 1 ) of thedischarge valve member 82. The adjustingpipe 84, which is configured into a cylindrical tubular form, is received in thepump body 10 on afuel outlet 72 side of thespring 83. The adjustingpipe 84 serves as a support member such that the other end portion of thespring 83 is engaged to the adjustingpipe 84. - As discussed above, the
discharge valve arrangement 70 includes thedischarge valve device 80. Thedischarge valve device 80 includes thedischarge valve member 82, thespring 83 and the adjustingpipe 84, and thedischarge valve member 82 is urged by the urging force of thespring 83 that is engaged to the adjustingpipe 84 at the other end portion of thespring 83. - The
discharge valve device 80 of thedischarge valve arrangement 70 is operated as follows. - When the
plunger 21 is moved upward in thecylinder hole 11, the pressure of the fuel in the pressurizingchamber 12 is increased. When the force, which is applied to thedischarge valve member 82 by the fuel on the pressurizingchamber 12 side (the upstream side) of thedischarge valve member 82, becomes larger than a sum of the resilient force of thespring 83 and the force of the fuel on thefuel outlet 72 side (the downstream side) of thedischarge valve member 82, thedischarge valve member 82 is lifted away from thevalve seat 85. That is, thedischarge valve device 80 is placed into a valve open state. In this way, the high pressure fuel, which is pressurized in the pressurizingchamber 12, is discharged to thefuel outlet 72 through thedischarge passage 71. - In contrast, when the
plunger 21 is moved downward in thecylinder hole 11, the pressure of the fuel in the pressurizingchamber 12 is decreased. When the force, which is applied to thedischarge valve member 82 by the fuel on the upstream side of thedischarge valve member 82, becomes larger than the sum of the resilient force of thespring 83 and the force of the fuel on the downstream side of thedischarge valve member 82, thedischarge valve member 82 is seated against thevalve seat 85. That is, thedischarge valve device 80 is placed into a valve closed state. In this way, it is possible to limit a backflow of the fuel from the downstream side of thedischarge valve member 82 into the pressurizingchamber 12 located on the upstream side of thedischarge valve member 82. - As discussed above, the
discharge valve device 80 of thedischarge valve arrangement 70 serves as a check valve, which limits the backflow of the high pressure fuel that is discharged from the pressurizingchamber 12 toward thefuel outlet 72. - Next, the operation of the
high pressure pump 1 will be described. - (1) Intake Stroke
- When the
plunger 21 is moved downward from the top dead center toward the bottom dead center in thecylinder hole 11 by the rotation of the camshaft, the volume of the pressurizingchamber 12 is increased, and the fuel in the pressurizingchamber 12 is depressurized. At this time, in thedischarge valve arrangement 70, thedischarge valve member 82 of thedischarge valve device 80 is seated against thevalve seat 85, so that thedischarge passage 71 is closed. Furthermore, in theintake valve arrangement 50, theintake valve 55 is moved in the right direction inFIG. 1 due to the pressure difference between the pressurizingchamber 12 and thesupply passage 52 against the urging force of the first spring 57, so that theintake valve 55 is placed in the valve open state. At this time, the energization of thecoil 611 of theelectromagnetic drive arrangement 60 is stopped, so that themovable core 63 and theneedle 67 integrated therewith are moved by the urging force of thesecond spring 68 in the right direction inFIG. 1 . Therefore, theneedle 67 and theintake valve 55 contact with each other, and theintake valve 55 is held in the valve open state. Thereby, the fuel is drawn from thesupply passage 52 into the pressurizingchamber 12. - In the intake stroke, the
plunger 21 is moved downward, so that the volume of thevariable volume chamber 30 is decreased. Thus, the fuel of thevariable volume chamber 30 is outputted to thedamper chamber 40 through thereturn passage 31. - In this instance, a ratio between the cross-sectional area of the
large diameter portion 211 and the cross-sectional area of thevariable volume chamber 30 is generally 1:0.6. Thus, a ratio between the amount of increase in the volume of the pressurizingchamber 12 and the amount of decrease in the volume of thevariable volume chamber 30 is generally 1:0.6. Therefore, about 60% of the fuel, which is drawn into the pressurizingchamber 12, is supplied from thevariable volume chamber 30, and about 40% of the remaining fuel is drawn from the fuel inlet. In this way, an intake efficiency of fuel into the pressurizingchamber 12 is improved. - (2) Metering Stroke
- When the
plunger 21 is moved upward from the bottom dead center toward the top dead center in thecylinder hole 11 by the rotation of the camshaft, the volume of the pressurizingchamber 12 is decreased. At this time, the energization of thecoil 611 is stopped until the predetermined timing (predetermined time point), so that theneedle 67 and theintake valve 55 are urged by the urging force of thesecond spring 68 in the right direction inFIG. 1 and are thereby placed at the right side position inFIG. 1 . Thereby, thesupply passage 52 is kept in the open state. Thus, the low pressure fuel, which is once drawn into the pressurizingchamber 12, is returned to thesupply passage 52. As a result, the pressure of the pressurizingchamber 12 is not increased. - In the metering stroke, the
plunger 21 is moved upward, so that the volume of thevariable volume chamber 30 is increased. Thus, the fuel of thedamper chamber 40 flows into thevariable volume chamber 30 through thereturn passage 31. - At this time, about 60% of the volume of the low pressure fuel, which is discharged from the pressurizing
chamber 12 toward thedamper chamber 40 side, is drawn into thevariable volume chamber 30 from thedamper chamber 40. Thereby, about 60% of the fuel pressure pulsation is reduced. - (3) Pressurizing Stroke
- At the predetermined timing (predetermined time point) during the movement of the plunger from the bottom dead center toward the top dead center in the
cylinder hole 11, thecoil 611 is energized. Then, a magnetic attractive force is generated between thestationary core 62 and themovable core 63 due to the generation of the magnetic field from thecoil 611. When this magnetic attractive force becomes larger than a difference between the resilient force of thesecond spring 68 and the resilient force of the first spring 57, themovable core 63 and theneedle 67 are moved toward thestationary core 62 side (in the left direction inFIG. 1 ). Thereby, the urging force of theneedle 67 against theintake valve 55 is released. Theintake valve 55 is moved toward theseat 54 side by the resilient force of the first spring 57 and the force generated by the flow of the low pressure fuel, which is outputted from the pressurizingchamber 12 toward thedamper chamber 40. Thus, theintake valve 55 is seated against theseat 54, so that thesupply passage 52 is closed. - Since the time of seating the
intake valve 55 against theseat 54, the pressure of the fuel in the pressurizingchamber 12 is increased as theplunger 21 is moved upward toward the top dead center of theplunger 21. In thedischarge valve arrangement 70, thedischarge valve member 82 of thedischarge valve device 80 is opened when the force, which is applied to thedischarge valve member 82 by the pressure of the fuel on the upstream side of thedischarge valve member 82, becomes larger than a sum of the urging force of thespring 83 and the force, which is applied to thedischarge valve member 82 by the pressure of the fuel on the downstream side of thedischarge valve member 82. In this way, the high pressure fuel, which is pressurized in the pressurizingchamber 12, is discharged from thefuel outlet 72 through thedischarge passage 71. - In the middle of the pressurizing stroke, the energization of the
coil 611 is stopped. The force, which is applied to theintake valve 55 from the pressure of the fuel in the pressurizingchamber 12, is larger than the urging force of thesecond spring 68, so that theintake valve 55 is kept in the valve closed state. - The
high pressure pump 1 repeats the intake stroke, the metering stroke and the pressurizing stroke, so that the fuel, which is required by the internal combustion engine, is pressurized and is discharged from thehigh pressure pump 1. - When the timing of energizing the
coil 611 is shifted to earlier timing, the time period of the metering stroke is shortened, and the time period of the pressurizing stroke is lengthened. Therefore, the fuel, which is returned from the pressurizingchamber 12 to thesupply passage 52, is reduced, and the fuel, which is outputted from thedischarge passage 71, is increased. In contrast, when the timing of energizing thecoil 611 is shifted to later timing, the time period of the metering stroke is lengthened, and the time period of the discharge stroke is shortened. Therefore, the fuel, which is returned from the pressurizingchamber 12 to thesupply passage 52, is increased, and the fuel, which is outputted from thedischarge passage 71, is decreased. - As discussed above, the quantity of fuel, which is discharged from the
high pressure pump 1, is controlled to the required quantity, which is required by the internal combustion engine, by controlling the timing of energizing thecoil 611. - Next, advantages of the present embodiment will be described.
- In the present embodiment, the
gas chamber 32 is placed at the location adjacent to thevariable volume chamber 30 of thehigh pressure pump 1. Thegas chamber 32 is formed by theinner blocking wall 33 placed adjacent to thevariable volume chamber 30, the seal element (serving as the outer blocking wall) 25 and thenitrogen gas 35 sealed in thespace 37 between theinner blocking wall 33 and theseal element 25. Therefore, even when the heat of an engine head, which is heated to the high temperature and is placed adjacent to the cam that drives the plunger to reciprocate the same, is conducted toward the fuel in thevariable volume chamber 30, the influence of the heat from the engine head is blocked or alleviated by thenitrogen gas 35 in thegas chamber 32, which is placed in the heat conduction path between the engine head and thevariable volume chamber 30. Furthermore, even when the high temperature lubricating oil (including engine oil) is scattered from the cam or its adjacent area and is adhered to the outer wall of theseal element 25 to cause conduction of the heat from the adhered high temperature lubricating oil to the fuel in thevariable volume chamber 30, the influence of the heat of the adhered high temperature lubricating oil is blocked or alleviated by thenitrogen gas 35 in thegas chamber 32, which is placed between the adhered high temperature lubricating oil and the fuel in thevariable volume chamber 30. - Here, a thermal conductivity of the
nitrogen gas 35 in thegas chamber 32 is 25.76 mW/(m·K) under the temperature of 25 degrees Celsius and the atmospheric pressure of 1 atm. This thermal conductivity of thenitrogen gas 35 is much lower than that of the metal material of thehigh pressure pump 1 and of the other solid materials. Therefore, thenitrogen gas 35 can effectively block or limit the conduction of the heat to the fuel in thevariable volume chamber 30. - Furthermore, the peripheral wall of the one
end portion 331 of theinner blocking wall 33 of thegas chamber 32 is welded to the inner peripheral surface of theseal element 25 at thewelding portion 34 a all around the oneend portion 331 in the circumferential direction, and the outer peripheral wall of theother end portion 332 of theinner blocking wall 33 is welded to the inner peripheral surface of theseal element 25 at thewelding portion 34 b all around theother end portion 332 in the circumferential direction. Thereby, thenitrogen gas 35 in thegas chamber 32 is sealed in the airtight state in thespace 37. Thus, the heat conduction blocking function (or the heat conducting limiting function) of thenitrogen gas 35 in thegas chamber 32 is stably maintained. - In this way, the increasing of the temperature of the fuel in the
variable volume chamber 30 to the high temperature can be limited by the heat conduction blocking function (or the heat conducting limiting function) of thenitrogen gas 35 in thegas chamber 32, which is adjacent to thevariable volume chamber 30, and thereby the vaporization of the fuel in thevariable volume chamber 30 can be limited. Thus, it is possible to limit the occurrence of the operational malfunction of thehigh pressure pump 1, i.e., the difficulty of drawing the fuel by thehigh pressure pump 1 caused by the vaporization of the fuel in thevariable volume chamber 30. - Furthermore, at the time of repeating the intake stroke, the metering stroke and the pressurizing stroke at the
high pressure pump 1 of the present embodiment, the fuel in thevariable volume chamber 30 is outputted to thedamper chamber 40 and is then returned to thedamper chamber 40 in response to the moving up and moving down of theplunger 21. At this time, theinner blocking wall 33, which is resiliently deformable and is interposed between the fuel in thevariable volume chamber 30 and thenitrogen gas 35 in thegas chamber 32, functions as the pulsation damper for the fuel in thevariable volume chamber 30. Thus, the pressure pulsation of the fuel in thevariable volume chamber 30 is reduced or minimized. - The fuel pressure pulsation reducing effect of the
inner blocking wall 33, which functions as the pulsation damper for the fuel in thevariable volume chamber 30, and the fuel pressure pulsation reducing effect, which is implemented by thedamper chamber 40, can further reduce the pressure pulsation of the low pressure fuel, which is supplied to the pressurizingchamber 12. Thereby, the appropriate operation of thehigh pressure pump 1 can be more effectively ensured. - Furthermore, the one
end portion 331 of theinner blocking wall 33, which is the component of thegas chamber 32, is installed such that the wall surface of the oneend portion 331 of theinner blocking wall 33, which is axially located on the pressurizingchamber 12 side, is axially opposed to thestep surface 213 of theplunger 21, and the wall surface of the oneend portion 331 of theinner blocking wall 33, which is axially located on the side opposite from the pressurizingchamber 12, contacts the other end portion of theseal member 24, which is axially located on the pressurizingchamber 12 side. Therefore, theinner blocking wall 33 functions as the stopper of theplunger 21 at the time of reciprocating theplunger 21 in thecylinder hole 11. Also, theinner blocking wall 33 cooperates with theseal element 25, which contacts both of the one end portion of theseal member 24 axially located on thespring seat 27 side and the outer peripheral portion of theseal member 24 radially located on the side opposite from thesmall diameter portion 212, to function as the holder, which securely holds, i.e., axially clamps theseal member 24. - That is, the
inner blocking wall 33 of thegas chamber 32 has the function, which is previously implemented in a plunger stopper in a previously proposed high pressure pump. Therefore, the plunger stopper, which is used in the previously proposed high pressure pump, is not required in thehigh pressure pump 1 of the present embodiment. Thus, the number of the components of thehigh pressure pump 1 can be reduced, and thereby the manufacturing costs of thehigh pressure pump 1 can be reduced. - Furthermore, in the present embodiment, the
seal element 25, which is also employed in the previously proposed high pressure pump, is used as the outer blocking wall of thegas chamber 32, so that it is possible to limit an increase in the number of components, which are required to form thegas chamber 32. Therefore, it is possible to limit an increase in the manufacturing costs of thehigh pressure pump 1. -
FIG. 3 shows a plunger arrangement of a high pressure pump according to a second embodiment of the present invention. In the following embodiments, components, which are similar to those of the first embodiment, will be indicated by the same reference numerals and will not be redundantly described. - The
plunger arrangement 20 of thehigh pressure pump 2 of the present embodiment will be described with referent oFIG. 3 . The other remaining structure of thehigh pressure pump 2 of the present embodiment, which is other than theplunger arrangement 20, is the same as that of thehigh pressure pump 1 of the first embodiment shown inFIG. 1 and thereby will not be described further. - Similar to the first embodiment, the
plunger arrangement 20 includes theplunger 21, theseal member 24, theseal element 25, theplunger spring 28 and thevariable volume chamber 30. - In the present embodiment, a
gas chamber 32A, which is adjacent to thevariable volume chamber 30 of thehigh pressure pump 2, includes aninner blocking wall 33A in place of theinner blocking wall 33 of the first embodiment. Similar to the first embodiment, theinner blocking wall 33A is the resiliently deformable member and functions as the pulsation damper for the fuel in thevariable volume chamber 30. - Similar to the first embodiment, one
end portion 331 a of theinner blocking wall 33A, which is axially located on the side opposite from thedamper chamber 40, extends in the direction generally perpendicular to the central axis of thecylinder hole 11. Furthermore, a peripheral wall of the oneend portion 331 a of theinner blocking wall 33A is welded to the inner peripheral surface of theseal element 25 at thewelding portion 34 a all around the oneend portion 331 a in the circumferential direction like in the first embodiment. Unlike the first embodiment, theother end portion 332 a of theinner blocking wall 33A, which is axially located on thedamper chamber 40 side, extends in a direction generally perpendicular to the central axis of thecylinder hole 11. A peripheral wall of theother end portion 332 a of theinner blocking wall 33A is welded to the inner peripheral surface of theseal element 25 at awelding portion 34 c, which is different from thewelding portion 34 b of the first embodiment, all around theother end portion 332 a in the circumferential direction. - Similar to the first embodiment, the
nitrogen gas 35 is filled into and is sealed in thespace 37, which is defined between theinner blocking wall 33A and the seal element (serving as the outer blocking wall) 25. - In this way, the
inner blocking wall 33A, which is configured into the shape that is different from theinner blocking wall 33 of the first embodiment, the seal element (serving as the outer blocking wall) 25 and thenitrogen gas 35 airtightly sealed in thespace 37 between theinner blocking wall 33A and theseal element 25 form thegas chamber 32A of the present embodiment. - Furthermore, similar to the first embodiment, the one
end portion 331 a of theinner blocking wall 33A, which is the component of thegas chamber 32A, is installed such that the wall surface of the oneend portion 331 a of theinner blocking wall 33A, which is axially located on the pressurizingchamber 12 side, is axially opposed to thestep surface 213 of theplunger 21, and the wall surface of the oneend portion 331 a of theinner blocking wall 33A, which is axially located on the side opposite from the pressurizingchamber 12, contacts the other end portion of theseal member 24, which is axially located on the pressurizingchamber 12 side. Therefore, similar to the first embodiment, theinner blocking wall 33A has the function similar to that of the plunger stopper of the previously proposed high pressure pump. - The other remaining structure of the
plunger arrangement 20 of the present embodiment, which is other than thegas chamber 32A, is the same as that of the first embodiment and thereby will not be described further. - Next, advantages of the present embodiment will be described.
- In the present embodiment, the
gas chamber 32, which is placed adjacent to thevariable volume chamber 30 of thehigh pressure pump 2, is formed by theinner blocking wall 33A placed adjacent to thevariable volume chamber 30, the seal element (serving as the outer blocking wall) 25 and thenitrogen gas 35 sealed in thespace 37 between theinner blocking wall 33 and theseal element 25. - Therefore, similar to the first embodiment, the increasing of the temperature of the fuel in the
variable volume chamber 30 to the high temperature can be limited by the heat conduction blocking function (or the heat conducting limiting function) of thenitrogen gas 35 in thegas chamber 32A, and thereby the vaporization of the fuel in thevariable volume chamber 30 can be limited. Thus, it is possible to limit the occurrence of the operational malfunction of thehigh pressure pump 2 caused by the vaporization of the fuel in thevariable volume chamber 30. - Furthermore, according to the present embodiment, the shape of the
inner blocking wall 33A of thegas chamber 32A and thewelding portion 34 c of theinner blocking wall 33A, which is welded to theseal element 25, are different from the shape of theinner blocking wall 33 of thegas chamber 32 and thewelding portion 34 b of theinner blocking wall 33, which is welded to theseal element 25, of the first embodiment. - Specifically, in the first embodiment, the
other end portion 332 of theinner blocking wall 33 of thegas chamber 32 extends in the direction generally parallel to the central axis of thecylinder hole 11, and the peripheral wall of theother end portion 332 of theinner blocking wall 33 is welded to the inner peripheral surface of theseal element 25 at thewelding portion 34 b all around theother end portion 332 in the circumferential direction. In contrast, according to the present embodiment, theother end portion 332 a of theinner blocking wall 33A of thegas chamber 32A extends in the direction generally perpendicular to the central axis of thecylinder hole 11, and the peripheral wall of theother end portion 332 a of theinner blocking wall 33A is welded to the inner peripheral surface of theseal element 25 at thewelding portion 34 c all around theother end portion 332 a in the circumferential direction. - When the
inner blocking wall 33A is configured into the above-described shape, which is different from that of theinner blocking wall 33 of the first embodiment, the volume of thegas chamber 32A (more specifically, the volume of the space 37) is increased in comparison to the volume of thegas chamber 32 of the first embodiment, as evident fromFIGS. 2 and 3 . Thereby, the volume of thenitrogen gas 35, which is sealed in thegas chamber 32A is increased in comparison to the volume of thenitrogen gas 35, which is sealed in thegas chamber 32 of the first embodiment. Thus, the heat conduction blocking function (or the heat conducting limiting function) of thenitrogen gas 35 in thegas chamber 32A is further enhanced in the second embodiment in comparison to the first embodiment. Thus, it is possible to further limit the occurrence of the operational malfunction of thehigh pressure pump 2 caused by the vaporization of the fuel in thevariable volume chamber 30. - The other advantages of the present embodiment are similar to those of the first embodiment. These other advantages of the present embodiment include, for example, the reduction of the pressure pulsation of the low pressure fuel supplied to the pressurizing
chamber 12 implemented by the fuel pressure pulsation reducing effect of theinner blocking wall 33A, which serves as the pulsation damper for the fuel in thevariable volume chamber 30. -
FIG. 4 shows a plunger arrangement of a high pressure pump according to a third embodiment of the present invention. - The
plunger arrangement 20 of thehigh pressure pump 3 of the present embodiment will be described with referent oFIG. 4 . The other remaining structure of thehigh pressure pump 2 of the present embodiment, which is other than theplunger arrangement 20, is the same as that of thehigh pressure pump 1 of the first embodiment shown inFIG. 1 and thereby will not be described further. - Similar to the first embodiment, the
plunger arrangement 20 includes theplunger 21, theseal member 24, theseal element 25, theplunger spring 28 and thevariable volume chamber 30. Unlike the first embodiment, theplunger arrangement 20 of the present embodiment includes aplunger stopper 23. - The
plunger stopper 23 is configured into an annular form and surrounds thesmall diameter portion 212 of theplunger 21. An end surface of theplunger stopper 23, which is axially located on the pressurizingchamber 12 side, is axially recessed toward thespring seat 27 side to form a recess. Anend surface 231 of theplunger stopper 23, which is radially located on the outer side of the recess and is axially directed to the pressurizingchamber 12 side (i.e., is axially located on the pressurizingchamber 12 side), is joined to or securely connected to thepump body 10. Anend surface 232 of the recess of theplunger stopper 23, which is directed to the pressurizingchamber 12 side (i.e., is axially located on the pressurizingchamber 12 side), is axially opposed to thestep surface 213, which is formed between thelarge diameter portion 211 and thesmall diameter portion 212 of theplunger 21. - Therefore, the
end surface 232 of theplunger stopper 23, which is axially opposed to thestep surface 213 of theplunger 21, functions as the stopper, which is adapted to abut against thestep surface 213 of theplunger 21 and thereby to limit the reciprocating movement of theplunger 21 in thecylinder hole 11, particularly the downward movement of theplunger 21 in thecylinder hole 11 in a direction away from the top dead center toward the bottom dead center. - A plurality of groove passages (only one is shown in
FIG. 4 ) 23 a, which serve as radial passages, is formed in theplunger stopper 23 to radially extend from the interior of the recess to the outer peripheral edge of theplunger stopper 23 to enable fluid communication therebetween. Thegroove passages 23 a of theplunger stopper 23 communicate between one area (radially inner area) of thevariable volume chamber 30, which is defined between thestep surface 213 of theplunger 21 and theplunger stopper 23 upon lifting of thestep surface 213 of theplunger 21 from theend surface 232 of theplunger stopper 23, to another area (radially outer area) of thevariable volume chamber 30, which is communicated with thedamper chamber 40. - The
seal member 24 is installed around thesmall diameter portion 212 of theplunger 21 at an axial location, which is on thespring seat 27 side of theplunger stopper 23, such that theseal member 24 surrounds thesmall diameter portion 212 in the circumferential direction. The other end portion of theseal member 24, which is axially located on the pressurizingchamber 12 side, contacts a wall surface of theplunger stopper 23, which is axially located on thespring seat 27 side. Therefore, theplunger stopper 23 cooperates with theseal element 25, which contacts both of the one end portion of theseal member 24 axially located on thespring seat 27 side and the radially outer portion of theseal member 24 radially located on the side opposite from the small diameter portion, to function as the holder, which securely holds, i.e., axially clamps theseal member 24. - The
seal element 25, theplunger spring 28 and thevariable volume chamber 30 are arranged in a manner similar to that of the first embodiment. - In the present embodiment, a
gas chamber 32B, which is adjacent to thevariable volume chamber 30 of thehigh pressure pump 3, includes aninner blocking wall 33B in place of theinner blocking wall 33 of the first embodiment. Similar to the first embodiment, theinner blocking wall 33B is the resiliently deformable member and functions as the pulsation damper for the fuel in thevariable volume chamber 30. - Unlike the first embodiment, one
end portion 331 b of theinner blocking wall 33B, which is axially located on the side opposite from thedamper chamber 40, extends in a direction generally parallel to the central axis of thecylinder hole 11. Furthermore, a peripheral wall of the oneend portion 331 b of theinner blocking wall 33B is welded to the inner peripheral surface of theseal element 25 at thewelding portion 34 a all around the oneend portion 331 b in the circumferential direction like in the first embodiment. - In the present embodiment, due to the provision of the
plunger stopper 23, the shape of the oneend portion 331 b of theinner blocking wall 33B is different from that of the first embodiment. For example, the peripheral wall of the oneend portion 331 b of theinner blocking wall 33B contacts an outer peripheral wall of theplunger stopper 23. - Similar to the first embodiment, the
other end portion 332 b of theinner blocking wall 33B, which is axially located on thedamper chamber 40 side, extends in the direction generally parallel to the central axis of thecylinder hole 11. A peripheral wall of theother end portion 332 b of theinner blocking wall 33B is welded to the inner peripheral surface of theseal element 25 at thewelding portion 34 b all around theother end portion 332 b in the circumferential direction, like in the first embodiment. - Similar to the first embodiment, the
nitrogen gas 35 is sealed into thespace 37, which is held between theinner blocking wall 33B and the seal element (serving as the outer blocking wall) 25. - The
inner blocking wall 33B, the seal element (serving as the outer blocking wall) 25 and thenitrogen gas 35 airtightly sealed therebetween form thegas chamber 32B of the present embodiment. - Next, advantages of the present embodiment will be described.
- In the present embodiment, the
gas chamber 32B, which is placed adjacent to thevariable volume chamber 30 of thehigh pressure pump 3, is formed by theinner blocking wall 33B placed adjacent to thevariable volume chamber 30, the seal element (serving as the outer blocking wall) 25 and thenitrogen gas 35 sealed in thespace 37 between theinner blocking wall 33B and theseal element 25. Therefore, similar to the first embodiment, the increasing of the temperature of the fuel in thevariable volume chamber 30 to the high temperature can be limited by the heat conduction blocking function (or the heat conducting limiting function) of thenitrogen gas 35 in thegas chamber 32B, and thereby the vaporization of the fuel in thevariable volume chamber 30 can be limited. Thus, it is possible to limit the occurrence of the operational malfunction of thehigh pressure pump 3 caused by the vaporization of the fuel in thevariable volume chamber 30. - Furthermore, similar to the first embodiment, the
inner blocking wall 33B of thegas chamber 32B, which is resiliently deformable, functions as the pulsation damper to reduce or minimize the fuel pressure pulsation of the fuel in thevariable volume chamber 30. Therefore, it contributes to the reduction or minimization of the pressure pulsation of the low pressure fuel, which is supplied to the pressurizingchamber 12. - In the present embodiment, the
plunger stopper 23 is provided. Theplunger stopper 23 functions as the stopper for the reciprocating movement of theplunger 21. Also, theplunger stopper 23 cooperates with theseal element 25 to function as the holder, which securely holds, i.e., axially clamps theseal member 24. Therefore, the functions, which are implemented by theinner blocking wall 33 of the first embodiment, are not implemented by theinner blocking wall 33B of the present embodiment. - Thereby, even in the
high pressure pump 3 of the present embodiment, the advantages similar to those of the first embodiment can be achieved by providing thegas chamber 32B, which is formed by theinner blocking wall 33B, which is placed adjacent to thevariable volume chamber 30 and functions as the pulsation damper, the seal element (serving as the outer blocking wall) 25 and thenitrogen gas 35 sealed in thespace 37 formed between theinner blocking wall 33 and theseal element 25. -
FIG. 5 shows a plunger arrangement of a high pressure pump according to a fourth embodiment of the present invention. - The
plunger arrangement 20 of thehigh pressure pump 4 of the present embodiment will be described with referent oFIG. 5 . The other remaining structure of thehigh pressure pump 4 of the present embodiment, which is other than theplunger arrangement 20, is the same as that of thehigh pressure pump 1 of the first embodiment shown inFIG. 1 and thereby will not be described further. - Similar to the third embodiment, the
plunger arrangement 20 includes theplunger 21, theplunger stopper 23, theseal member 24, theseal element 25, theplunger spring 28 and thevariable volume chamber 30. - A
gas chamber 32C, which is placed adjacent to thevariable volume chamber 30 of thehigh pressure pump 4 of the present embodiment, includes theseal element 25, which now serves as the inner blocking wall, in place of theinner blocking wall 33B of the third embodiment. Thegas chamber 32C further includes anouter blocking wall 36 in place of theseal element 25, which serves as the outer blocking wall in the third embodiment. Theouter blocking wall 36 is made of a heat insulation member. Oneend portion 361 of the outer blockingwall 36, which is located on the side opposite from thedamper chamber 40, extends in a direction that is generally parallel to the central axis of thecylinder hole 11. Theother end portion 362 of the outer blockingwall 36, which is located on the side where thedamper chamber 40 is located, extends in a direction generally perpendicular to the central axis of thecylinder hole 11. A peripheral wall of the oneend portion 361 of the outer blockingwall 36 is welded to the inner peripheral surface of theseal element 25 at awelding portion 34 d all around the oneend portion 361 in the circumferential direction. An outer peripheral wall of theother end portion 362 of the outer blockingwall 36 is welded to the inner peripheral surface of theseal element 25 at awelding portion 34 e all around theother end portion 362 in the circumferential direction. - The
nitrogen gas 35 is sealed into thespace 37, which is held between the seal element (serving as the inner blocking wall) 25 and the outer blockingwall 36. - In this way, the
gas chamber 32C of the present embodiment is formed by the seal element (serving as the inner blocking wall) 25, the outer blockingwall 36 and thenitrogen gas 35 sealed in thespace 37 formed between theseal element 25 and the outer blockingwall 36. - The other remaining structure of the
high pressure pump 4 of the present embodiment, which is other than thegas chamber 32C of theplunger arrangement 20, is the same as that of thehigh pressure pump 3 of the third embodiment and thereby will not be described further. - Next, advantages of the present embodiment will be described.
- In the present embodiment, the
gas chamber 32C, which is placed adjacent to thevariable volume chamber 30 of thehigh pressure pump 4, is made by the seal element (serving as the inner blocking wall) 25, the outer blockingwall 36 made of the heat insulation member, and thenitrogen gas 35 sealed in thespace 37 formed between theseal element 25 and the outer blockingwall 36. - Therefore, in the present embodiment, similar to the third embodiment, the heat conduction blocking function (or the heat conduction limiting function) can be implemented by the
nitrogen gas 35 in thegas chamber 32C, and thereby it is possible to limit the occurrence of the operational malfunction of thehigh pressure pump 4 caused by the vaporization of the fuel in thevariable volume chamber 30. - Furthermore, the outer blocking
wall 36 is made of the heat insulation member. Therefore, the heat conduction blocking function (or the heat conduction limiting function) of the outer blockingwall 36 is implemented in addition to the heat conduction blocking function (or the heat conduction limiting function) ofnitrogen gas 35. As a result, the heat conduction blocking function of theentire gas chamber 32C is further increased, and thereby the operational malfunction of thehigh pressure pump 4 can be more effectively limited. - Now, modifications of the above embodiments will be described.
- In the first to fourth embodiments, the
nitrogen gas 35 is used as the gas, which is sealed in thespace 37 of thegas chamber space 37 of thegas chamber space 37 of thegas chamber high pressure pump space 37 discussed above, it is not absolutely necessary to seal the air into thespace 37 of thegas chamber space 37 may possibly be left as an open space unlike the first to fourth embodiments, in which thespace 37 is formed as the closed space. For instance, the oneend portion 361 of the outer blockingwall 36 may be spaced from theseal element 25 or may be engaged with theseal element 25 without entirely welding therebetween in the circumferential direction in a manner that enables the fluid communication between thespace 37 and the outside space located outside of the outer blockingwall 36. Therefore, at the time of connecting and securing theinner blocking wall wall 36 to theseal element 25, it is possible to use any other method, which is other than the welding-all-around theseal element 25. - Additional advantages and modifications will readily occur to those skilled in the art. The invention in its broader terms is therefore not limited to the specific details, representative apparatus, and illustrative examples shown and described.
Claims (11)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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JP2011015643A JP5209746B2 (en) | 2011-01-27 | 2011-01-27 | High pressure pump |
JP2011-15643 | 2011-01-27 |
Publications (1)
Publication Number | Publication Date |
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US20120195778A1 true US20120195778A1 (en) | 2012-08-02 |
Family
ID=46577508
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US13/352,626 Abandoned US20120195778A1 (en) | 2011-01-27 | 2012-01-18 | High pressure pump |
Country Status (2)
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US (1) | US20120195778A1 (en) |
JP (1) | JP5209746B2 (en) |
Cited By (11)
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US20130266465A1 (en) * | 2010-12-24 | 2013-10-10 | Toyota Jidosha Kabushiki Kaisha | High-pressure pump |
WO2015032558A1 (en) * | 2013-09-04 | 2015-03-12 | Continental Automotive Gmbh | High pressure pump |
WO2015032533A1 (en) * | 2013-09-04 | 2015-03-12 | Continental Automotive Gmbh | High pressure pump |
WO2015090676A1 (en) * | 2013-12-17 | 2015-06-25 | Delphi International Operations Luxembourg S.À R.L. | High pressure pump |
DE102015219772A1 (en) * | 2015-10-13 | 2016-10-06 | Continental Automotive Gmbh | Low-pressure damper and high-pressure fuel pump |
WO2016185006A1 (en) * | 2015-05-20 | 2016-11-24 | Delphi International Operations Luxembourg S.À R.L. | Fuel pump apparatus |
WO2017198360A1 (en) * | 2016-05-19 | 2017-11-23 | Robert Bosch Gmbh | High-pressure fuel pump |
IT201600081962A1 (en) * | 2016-08-03 | 2018-02-03 | Bosch Gmbh Robert | PUMPING GROUP FOR FUEL SUPPLEMENTATION, PREFERABLY GASOIL, TO AN INTERNAL COMBUSTION ENGINE |
US20180223782A1 (en) * | 2015-07-31 | 2018-08-09 | Toyota Jidosha Kabushiki Kaisha | Damper device |
DE102017203762A1 (en) | 2017-03-08 | 2018-09-13 | Continental Automotive Gmbh | High-pressure fuel pump for a fuel injection system |
US20190203684A1 (en) * | 2018-01-04 | 2019-07-04 | Continental Automotive Gmbh | High-Pressure Fuel Pump |
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JP5668978B2 (en) * | 2011-02-25 | 2015-02-12 | 株式会社デンソー | High pressure pump |
JP5939122B2 (en) * | 2012-10-09 | 2016-06-22 | 株式会社デンソー | High pressure pump |
JP6612541B2 (en) * | 2015-07-07 | 2019-11-27 | 株式会社Soken | Fuel pump |
KR102107462B1 (en) * | 2018-12-14 | 2020-05-07 | 주식회사 현대케피코 | Structure for prevent deformation of packing carrier of high pressure pump |
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US9567985B2 (en) * | 2010-12-24 | 2017-02-14 | Toyota Jidosha Kabushiki Kaisha | High-pressure pump |
US20130266465A1 (en) * | 2010-12-24 | 2013-10-10 | Toyota Jidosha Kabushiki Kaisha | High-pressure pump |
WO2015032558A1 (en) * | 2013-09-04 | 2015-03-12 | Continental Automotive Gmbh | High pressure pump |
WO2015032533A1 (en) * | 2013-09-04 | 2015-03-12 | Continental Automotive Gmbh | High pressure pump |
US10047743B2 (en) | 2013-09-04 | 2018-08-14 | Continental Automotive Gmbh | High pressure pump |
CN105008718A (en) * | 2013-09-04 | 2015-10-28 | 大陆汽车有限公司 | High pressure pump |
CN106103970A (en) * | 2013-12-17 | 2016-11-09 | 德尔福国际运营卢森堡有限公司 | High-pressure pump |
US10273921B2 (en) | 2013-12-17 | 2019-04-30 | Delphi Technologies Ip Limited | High pressure pump |
WO2015090676A1 (en) * | 2013-12-17 | 2015-06-25 | Delphi International Operations Luxembourg S.À R.L. | High pressure pump |
WO2016185006A1 (en) * | 2015-05-20 | 2016-11-24 | Delphi International Operations Luxembourg S.À R.L. | Fuel pump apparatus |
KR102501007B1 (en) | 2015-05-20 | 2023-02-17 | 델피 테크놀로지스 아이피 리미티드 | fuel pump unit |
KR20180008504A (en) * | 2015-05-20 | 2018-01-24 | 델피 인터내셔널 오퍼레이션즈 룩셈부르크 에스.에이 알.엘. | Fuel pump device |
US10323615B2 (en) | 2015-05-20 | 2019-06-18 | Delphi Technologies Ip Limited | Fuel pump apparatus |
US10883462B2 (en) * | 2015-07-31 | 2021-01-05 | Toyota Jidosha Kabushiki Kaisha | Damper device with a plurality of stacked diaphragms coupled together by a coupler having holders forming a space provided between a peripheral weld of the diaphragms and the coupler |
US20180223782A1 (en) * | 2015-07-31 | 2018-08-09 | Toyota Jidosha Kabushiki Kaisha | Damper device |
DE102015219772A1 (en) * | 2015-10-13 | 2016-10-06 | Continental Automotive Gmbh | Low-pressure damper and high-pressure fuel pump |
CN109154266A (en) * | 2016-05-19 | 2019-01-04 | 罗伯特·博世有限公司 | High-pressure fuel pump |
WO2017198360A1 (en) * | 2016-05-19 | 2017-11-23 | Robert Bosch Gmbh | High-pressure fuel pump |
IT201600081962A1 (en) * | 2016-08-03 | 2018-02-03 | Bosch Gmbh Robert | PUMPING GROUP FOR FUEL SUPPLEMENTATION, PREFERABLY GASOIL, TO AN INTERNAL COMBUSTION ENGINE |
DE102017203762A1 (en) | 2017-03-08 | 2018-09-13 | Continental Automotive Gmbh | High-pressure fuel pump for a fuel injection system |
US10837430B2 (en) | 2017-03-08 | 2020-11-17 | Vitesco Technologies GmbH | High-pressure fuel pump for a fuel injection system |
US20190203684A1 (en) * | 2018-01-04 | 2019-07-04 | Continental Automotive Gmbh | High-Pressure Fuel Pump |
Also Published As
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JP5209746B2 (en) | 2013-06-12 |
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Owner name: NIPPON SOKEN, INC., JAPAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:KOGA, TATSURO;MATSUMOTO, NORIYA;HISHINUMA, OSAMU;AND OTHERS;REEL/FRAME:027551/0326 Effective date: 20111226 Owner name: DENSO CORPORATION, JAPAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:KOGA, TATSURO;MATSUMOTO, NORIYA;HISHINUMA, OSAMU;AND OTHERS;REEL/FRAME:027551/0326 Effective date: 20111226 |
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