US20060228230A1 - Liquid pump - Google Patents
Liquid pump Download PDFInfo
- Publication number
- US20060228230A1 US20060228230A1 US10/568,812 US56881206A US2006228230A1 US 20060228230 A1 US20060228230 A1 US 20060228230A1 US 56881206 A US56881206 A US 56881206A US 2006228230 A1 US2006228230 A1 US 2006228230A1
- Authority
- US
- United States
- Prior art keywords
- valve piston
- chamber
- pressure
- fluid pump
- delivery element
- 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
- 239000007788 liquid Substances 0.000 title 1
- 239000012530 fluid Substances 0.000 claims abstract description 36
- 230000007423 decrease Effects 0.000 claims abstract 2
- 239000000446 fuel Substances 0.000 claims description 29
- 238000002347 injection Methods 0.000 claims description 6
- 239000007924 injection Substances 0.000 claims description 6
- 238000002485 combustion reaction Methods 0.000 claims description 5
- 230000006835 compression Effects 0.000 description 13
- 238000007906 compression Methods 0.000 description 13
- 238000011045 prefiltration Methods 0.000 description 7
- 230000010349 pulsation Effects 0.000 description 3
- 229910000831 Steel Inorganic materials 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 238000011144 upstream manufacturing Methods 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 239000002283 diesel fuel Substances 0.000 description 1
- 229920001971 elastomer Polymers 0.000 description 1
- 239000000806 elastomer Substances 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
Images
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C14/00—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations
- F04C14/24—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations characterised by using valves controlling pressure or flow rate, e.g. discharge valves or unloading valves
- F04C14/26—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations characterised by using valves controlling pressure or flow rate, e.g. discharge valves or unloading valves using bypass channels
- F04C14/265—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations characterised by using valves controlling pressure or flow rate, e.g. discharge valves or unloading valves using bypass channels being obtained by displacing a lateral sealing face
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M37/00—Apparatus or systems for feeding liquid fuel from storage containers to carburettors or fuel-injection apparatus; Arrangements for purifying liquid fuel specially adapted for, or arranged on, internal-combustion engines
- F02M37/0011—Constructional details; Manufacturing or assembly of elements of fuel systems; Materials therefor
- F02M37/0023—Valves in the fuel supply and return system
- F02M37/0029—Pressure regulator in the low pressure fuel system
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M37/00—Apparatus or systems for feeding liquid fuel from storage containers to carburettors or fuel-injection apparatus; Arrangements for purifying liquid fuel specially adapted for, or arranged on, internal-combustion engines
- F02M37/0047—Layout or arrangement of systems for feeding fuel
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M37/00—Apparatus or systems for feeding liquid fuel from storage containers to carburettors or fuel-injection apparatus; Arrangements for purifying liquid fuel specially adapted for, or arranged on, internal-combustion engines
- F02M37/04—Feeding by means of driven pumps
- F02M37/041—Arrangements for driving gear-type pumps
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M37/00—Apparatus or systems for feeding liquid fuel from storage containers to carburettors or fuel-injection apparatus; Arrangements for purifying liquid fuel specially adapted for, or arranged on, internal-combustion engines
- F02M37/22—Arrangements for purifying liquid fuel specially adapted for, or arranged on, internal-combustion engines, e.g. arrangements in the feeding system
- F02M37/32—Arrangements for purifying liquid fuel specially adapted for, or arranged on, internal-combustion engines, e.g. arrangements in the feeding system characterised by filters or filter arrangements
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M37/00—Apparatus or systems for feeding liquid fuel from storage containers to carburettors or fuel-injection apparatus; Arrangements for purifying liquid fuel specially adapted for, or arranged on, internal-combustion engines
- F02M37/22—Arrangements for purifying liquid fuel specially adapted for, or arranged on, internal-combustion engines, e.g. arrangements in the feeding system
- F02M37/32—Arrangements for purifying liquid fuel specially adapted for, or arranged on, internal-combustion engines, e.g. arrangements in the feeding system characterised by filters or filter arrangements
- F02M37/44—Filters structurally associated with pumps
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M37/00—Apparatus or systems for feeding liquid fuel from storage containers to carburettors or fuel-injection apparatus; Arrangements for purifying liquid fuel specially adapted for, or arranged on, internal-combustion engines
- F02M37/22—Arrangements for purifying liquid fuel specially adapted for, or arranged on, internal-combustion engines, e.g. arrangements in the feeding system
- F02M37/54—Arrangements for purifying liquid fuel specially adapted for, or arranged on, internal-combustion engines, e.g. arrangements in the feeding system characterised by air purging means
Definitions
- the present invention is based on a fluid pump as generically defined by the preamble to claim 1 .
- a fluid pump of this kind embodied in the form of a gear pump is known from DE 196 25 564 A1.
- This gear pump is provided for a fuel injection apparatus of an internal combustion engine and has a housing that contains a pump chamber.
- the pump chamber contains a pair of rotary driven gears that mesh with each other along their outer circumference.
- the gears deliver fuel as a delivery medium from an intake chamber connected to a reservoir, along delivery channels formed between the circumference of the gears and the circumference walls of the pump chamber, to a pressure chamber.
- the gear pump also has a pressure limiting valve to limit the pressure in the pressure chamber. When a predetermined pressure in the pressure chamber is exceeded, the pressure limiting valve opens a connecting conduit between the pressure chamber and the intake chamber.
- the pressure limiting valve has a valve piston, which is guided so that it can move inside a bore in a plane perpendicular to the rotation axes of the gears and cooperates with a valve seat.
- the valve piston is able to move in opposition to the force of a prestressed spring.
- the pressure limiting valve makes it possible to limit the pressure generated by the gear pump and thus to limit the fuel quantity delivered.
- the fluid pump is preceded by a filter through which the aspirated fluid flows or is followed by a filter through which the delivered fuel flows.
- the fluid pump delivers a varying fluid quantity depending on the degree to which the filter is soiled, a phenomenon that cannot be prevented by the pressure limiting valve.
- the fluid pump according to the present invention has the advantage over the prior art that in addition to limiting the delivery pressure, it also regulates the delivery quantity so that the delivery quantity is fixed regardless of the degree to which the filter is soiled. This is achieved simply in that the force exerted on the valve piston in the closing direction is varied as a function of the pressure prevailing downstream of the filter.
- the embodiment according to claim 2 achieves the function of delivery quantity regulation in a simple manner.
- the embodiment according to claim 5 permits a simple design of the pressure limiting valve.
- the embodiment according to claim 6 provides a simple design of the connecting conduit.
- the embodiment according to claim 9 allows the delivery medium to be displaced from the chamber or to flow into it as the valve piston moves in the bore.
- FIG. 1 shows a gear pump in a section along the line I-I in FIG. 2 ,
- FIG. 2 shows the gear pump in a section along the line II-II in FIG. 1 .
- FIG. 3 shows a schematic enlargement of the gear pump in a section along the line III-III in FIG. 2 .
- a fluid pump depicted in FIGS. 1 through 3 is embodied in the form of a gear pump and is positioned in a supply line, not shown, from a reservoir to a high-pressure fuel pump or fuel injection pump of a fuel injection apparatus of an internal combustion engine, for example belonging to a motor vehicle.
- the internal combustion engine is an autoignition engine and the fuel delivered by the gear pump is diesel fuel.
- the gear pump has a multipart housing that includes a housing part 10 and a cover part 12 . Between the housing part 10 and the cover part 12 , there is a pump chamber 14 that contains a pair of gears 16 , 18 that mesh with each other along their outer circumferences.
- the housing part 10 has two recesses 20 , 22 , each with a respective journal 24 , 26 protruding from its bottom.
- the journals 24 , 26 are of one piece with the housing part 10 and extend at least approximately parallel to each other.
- the journals 24 , 26 can be embodied as at least partially hollow.
- the gear 16 has a bore 17 by means of which it is supported on the journal 24 in rotary fashion.
- the gear 18 has a bore 19 by means of which it is supported on the journal 26 in rotary fashion.
- the journals 24 , 26 each define a rotation axis 25 , 27 for the respective gears 16 , 18 .
- the cover part 12 is attached to the housing part 10 , for example by means of a number of screws.
- the housing part 10 and the cover part 12 are preferably comprised of light metal, in particular aluminum.
- the gears 16 , 18 are preferably comprised of steel, in particular sintered steel.
- the gear pump has a drive shaft 30 that is supported so that it can rotate in the housing part 10 .
- the drive shaft 30 is positioned at least approximately coaxial to the journal 24 ; the housing part 10 has a bore that continues inside the journal 24 , through which the drive shaft 30 extends.
- a corrugated sealing ring is installed between the bore and the drive shaft 30 in order to seal the housing part 10 .
- the drive shaft 30 is coupled to the gear 16 , for example by means of a coupling member 36 situated between the end of the journal 24 and the cover part 12 .
- the drive shaft 30 drives the gear 16 to rotate, which in turn transmits this rotary motion via face gearing to the gear 18 , which is likewise provided with face gearing and meshes with the gear 16 on its outer circumference.
- the tooth engagement of the gears 16 , 18 thus divides the pump chamber 14 into two subregions, a first subregion of which constitutes an intake chamber 40 and a second subregion of which constitutes a pressure chamber 42 .
- the intake chamber 40 is connected to pressure chamber 42 by means of a delivery conduit 44 formed respectively between the tooth grooves on the circumference surfaces of the gears 16 , 18 and the upper and lower circumference wall of the pump chamber 14 .
- the intake chamber 40 and pressure chamber 42 each have a connection opening in the wall of the housing part 10 or the cover 12 that connects the intake chamber 40 to an intake line, not shown, from the reservoir and connects the pressure chamber 42 via a delivery line, also not shown, to the intake chamber of the high-pressure fuel pump or the fuel injection pump.
- the connection opening in the intake chamber 40 constitutes an inlet opening 46 and the connection opening in the pressure chamber 42 constitutes an outlet opening 48 .
- the gear pump has a pressure limiting valve 50 that is situated in the housing, for example in the housing part 10 .
- the bottom of the recesses 20 , 22 constituting the pump chamber 14 have a groove 52 let into them, which extends between the pressure chamber 42 and the intake chamber 40 .
- the groove 52 has a length l, a width b, and a depth t. Viewed in the direction of the rotation axes 25 , 27 of the gears 24 , 26 , the groove 52 depicted in FIG. 3 extends approximately tangential to the gears 16 , 18 and its length l is dimensioned so that the groove 52 protrudes beyond the intersecting lines 54 of the top circle Dk of the gears 16 , 18 .
- the groove 52 is situated at least approximately in the center between the two gears 16 , 18 .
- the groove 52 thus constitutes a connecting conduit extending from the pressure chamber 42 to the intake chamber 40 .
- the bottom of the recesses 20 , 22 of the housing part 10 is spaced slightly apart from the end faces of the gears 16 , 18 in the axial direction.
- a bore 56 whose diameter d is preferably a little larger than the width b of the groove 52 is let into the bottom of the groove 52 .
- the bore 56 extends at least approximately parallel to the rotation axes 25 , 27 of the gears 16 , 18 and is preferably situated offset from a connecting line 58 between the rotation axes 25 , 27 of the gears 16 , 18 by a measurement H in the direction of the pressure chamber 42 .
- the measurement H is preferably between approximately 2 and 5 mm.
- a valve piston 60 that functions as the valve member of the pressure limiting valve 50 is guided so that it can slide in the bore 56 .
- a compression spring 62 for example in the form of the helical compression spring clamped between the valve piston 60 and the bottom of the bore 56 , presses the valve piston 60 toward the end surfaces of the gears 16 , 18 oriented toward it.
- the end surfaces of the gears 16 , 18 are embodied as at least approximately flat and are positioned at least approximately perpendicular to their rotation axes 25 , 27 .
- the valve piston 60 rests against the end surfaces of the gears 16 , 18 in the region in which their teeth engage with one another.
- the chamber 64 delimited in the bore 56 by the valve piston 60 at its rear end oriented away from the gears 16 , 18 communicates with the intake chamber 40 via a bore 66 in the housing part 10 .
- the pressure prevailing in the pressure chamber 42 acts on part of the end surface of the valve piston 60 oriented toward the gears 16 , 18 , generating a force on the valve piston 60 in opposition to the force exerted on it by the compression spring 62 . If the force of the compression spring 62 is greater than the force generated by the pressure prevailing in the pressure chamber 42 , then the valve piston 60 rests against the end surfaces of the gears 16 , 18 , which constitute a valve seat. The valve piston 60 , in cooperation with the gears 16 , 18 thus disconnects the passage through the groove 52 and therefore the connection between the pressure chamber 42 and the intake chamber 40 .
- the pressure at which the pressure limiting valve 50 opens can be varied by means of the prestressing of the compression spring 62 , the diameter of the valve piston 60 , and the position of the valve piston 60 in relation to the pressure chamber 42 and therefore the size of the end surface of the valve piston 60 acted on by the pressure prevailing in the pressure chamber 42 .
- the valve piston 60 With increasing pressure in the pressure chamber 42 , the valve piston 60 is slid further into the bore 56 so that the valve piston 60 opens an ever greater through flow cross section in the groove 52 .
- the maximum through flow cross section that the valve piston 60 opens in the groove 52 is preferably great enough to allow the entire fuel quantity delivered by the gears 16 , 18 to flow from the pressure chamber 42 back to the intake chamber 40 when the gear pump is not supposed to deliver any fuel.
- the cross-sectional area of the groove 52 that determines the maximum through flow cross section is preferably between 30 and 60 mm 2 .
- the gear pump also has a bypass valve 70 that can open a connection between the pressure chamber 42 and the intake chamber 40 when the pressure in the pressure chamber 42 is less than that in the intake chamber 40 . This can be the case particularly after the gear pump has run dry or when it is filled for the first time; the bypass valve 70 makes it possible to fill the gear pump and to bleed air from it.
- the bypass valve 70 has a valve member 72 ; the pressure prevailing in the pressure chamber 42 acts on this valve member 72 and pushes it toward a valve seat 74 on the housing part 10 .
- the valve member 72 is contained in a recess 76 of the groove 52 in the region of the groove that protrudes into the pressure chamber 42 .
- the valve member 72 can be comprised, for example, of an elastomer and the valve seat 74 can be embodied in the form of a flat seat. From the valve seat 74 , a bore 78 leads into the chamber 64 in the bore 56 behind the valve piston 60 and this chamber 64 is in turn connected to the intake chamber 40 via the bore 66 .
- the valve member 72 is also engaged by a closing spring 80 , which can be embodied, for example, as a prestressed tension spring contained in the bore 78 and engages the valve member 72 at one end and hooks onto the last coil of the compression spring 62 at the other end.
- the closing spring 80 pulls the valve member 72 toward the valve seat 74 with a slight force, thus bringing it into contact with the valve seat 74 when the gear pump is not in operation.
- the bypass valve 70 opens by virtue of its valve member 72 lifting away from the valve seat 74 so that fuel can travel from the intake chamber 40 directly into the pressure chamber 42 and the pressure chamber 42 is filled with fuel. If, during further operation of the gear pump, the pressure in the pressure chamber 42 increases and is greater than the pressure in the intake chamber 40 , then this presses the valve member 72 against the valve seat 74 so that the bypass valve 70 closes, thus disconnecting the pressure chamber 42 from the intake chamber 40 .
- the gear pump is preceded in the fuel line by a filter 82 embodied in the form of a prefilter through which the fuel aspirated from the reservoir by the gear pump flows.
- the gear pump is also followed in the fuel line by an additional filter 83 embodied in the form of a fine filter through which the fuel delivered by the gear pump flows to the high-pressure fuel pump for the fuel injection pump.
- the pump it is also possible the pump to be provided only with the prefilter 82 upstream of the gear pump and not the fine filter.
- the gear pump has an additional housing part 84 that has a recess oriented toward the housing part 10 in which a pressure chamber 85 is provided.
- the pressure chamber 85 is connected to a region downstream of the fine filter 83 so that the same pressure prevails in the pressure chamber 83 as downstream of the fine filter 83 .
- the pressure chamber 85 is connected to a region downstream of the prefilter 82 so that the same pressure prevails in the pressure chamber 85 as downstream of the prefilter 82 and upstream of the gear pump.
- the pressure chamber 85 in the recess of the housing part 84 is delimited by a moving wall 86 that is embodied, for example, in the form of a diaphragm.
- a sleeve 87 in the recess of the housing part 84 prestresses the diaphragm 86 .
- the middle region of the diaphragm 86 supports a rod 88 that protrudes through a bore in the housing part 10 and rests against the valve piston 60 .
- a prestressed spring 89 embodied, for example, in the form of a helical compression spring is contained in the part of the recess in the housing 84 that the diaphragm 86 separates from the pressure chamber 85 .
- the pressure prevailing in the pressure chamber 85 thus acts on one side of the diaphragm 86 and the prestressed spring 89 acts on the other.
- the spring 89 pushes the diaphragm 86 and with it, the rod 88 , toward the valve piston 60 , which exerts an additional force on the valve piston 60 in the closing direction in addition to that of the compression spring 62 .
- the pressure in the pressure chamber 85 is high, then the diaphragm 86 and with it, the rod 88 , is pulled away from the valve piston 60 counter to the force of the spring 89 so that a lesser force acts on the valve piston 60 in the closing direction.
- the fine filter 83 or the prefilter 82 is slightly soiled, then only a slight pressure loss occurs as the fuel flows through so that a relatively high pressure prevails downstream of the filter. In this case, the high pressure also prevails in the pressure chamber 85 so that the opening motion of the valve piston 60 is essentially determined by the compression spring 62 . If the fine filter 83 or the prefilter 82 are heavily soiled, then a greater pressure loss occurs as the fuel flows through so that a relatively low pressure prevails downstream of the filter.
- a low pressure also prevails in the pressure chamber 85 so that in addition to the force of the compression spring 62 , the force of the spring 89 also acts on the valve piston 60 in the closing direction and this valve piston 60 only opens in the presence of a higher pressure in the pressure chamber 42 .
- the gear pump then generates a correspondingly higher pressure and delivers a greater quantity of fuel, thus compensating for the loss in pressure and quantity due to the filter 82 and/or 83 .
- the fluid pump can also be alternatively embodied, for example, as an internal gear pump or as a vane pump in which the pressure limiting valve 50 can be used to regulate pressure and the pressure chamber 85 can be used to regulate delivery quantity in the same ways as described above.
Abstract
A fluid pump having a housing containing a pump chamber containing least one rotary driven delivery element which delivers fluid to a pressure chamber from an intake chamber connected to a reservoir. A pressure limiting valve for limiting the pressure in the pressure chamber has a valve piston which is acted on in the closing direction by a prestressed closing spring and in the opening direction by the pressure in the pressure chamber and, when a predetermined pressure in the pressure chamber is exceeded, opens a connecting conduit from the pressure chamber to the intake chamber. The fluid pump is preceded by a filter and/or is followed by a filter and contains a pressure chamber connected to a region downstream of the preceding filter or a downstream of the subsequent filter. The pressure in pressure chamber influences the force on the valve piston in the closing direction in such a way that as the pressure in the pressure chamber decreases, the force on the valve piston in the closing direction increases.
Description
- The present invention is based on a fluid pump as generically defined by the preamble to claim 1.
- A fluid pump of this kind embodied in the form of a gear pump is known from DE 196 25 564 A1. This gear pump is provided for a fuel injection apparatus of an internal combustion engine and has a housing that contains a pump chamber. The pump chamber contains a pair of rotary driven gears that mesh with each other along their outer circumference. The gears deliver fuel as a delivery medium from an intake chamber connected to a reservoir, along delivery channels formed between the circumference of the gears and the circumference walls of the pump chamber, to a pressure chamber. The gear pump also has a pressure limiting valve to limit the pressure in the pressure chamber. When a predetermined pressure in the pressure chamber is exceeded, the pressure limiting valve opens a connecting conduit between the pressure chamber and the intake chamber. The pressure limiting valve has a valve piston, which is guided so that it can move inside a bore in a plane perpendicular to the rotation axes of the gears and cooperates with a valve seat. The valve piston is able to move in opposition to the force of a prestressed spring. The pressure limiting valve makes it possible to limit the pressure generated by the gear pump and thus to limit the fuel quantity delivered. Usually, the fluid pump is preceded by a filter through which the aspirated fluid flows or is followed by a filter through which the delivered fuel flows. The fluid pump delivers a varying fluid quantity depending on the degree to which the filter is soiled, a phenomenon that cannot be prevented by the pressure limiting valve.
- The fluid pump according to the present invention, with the characterizing features of claim 1, has the advantage over the prior art that in addition to limiting the delivery pressure, it also regulates the delivery quantity so that the delivery quantity is fixed regardless of the degree to which the filter is soiled. This is achieved simply in that the force exerted on the valve piston in the closing direction is varied as a function of the pressure prevailing downstream of the filter.
- Advantageous embodiments and modifications of the fluid pump according to the present invention are disclosed in the dependent claims. The embodiment according to claim 2 achieves the function of delivery quantity regulation in a simple manner. The embodiment according to claim 5 permits a simple design of the pressure limiting valve. The embodiment according to claim 6 provides a simple design of the connecting conduit. The embodiment according to claim 9 allows the delivery medium to be displaced from the chamber or to flow into it as the valve piston moves in the bore.
- An exemplary embodiment of the present invention is shown in the drawings and will be explained in detail in the subsequent description.
-
FIG. 1 shows a gear pump in a section along the line I-I inFIG. 2 , -
FIG. 2 shows the gear pump in a section along the line II-II inFIG. 1 , and -
FIG. 3 shows a schematic enlargement of the gear pump in a section along the line III-III inFIG. 2 . - A fluid pump depicted in
FIGS. 1 through 3 is embodied in the form of a gear pump and is positioned in a supply line, not shown, from a reservoir to a high-pressure fuel pump or fuel injection pump of a fuel injection apparatus of an internal combustion engine, for example belonging to a motor vehicle. The internal combustion engine is an autoignition engine and the fuel delivered by the gear pump is diesel fuel. The gear pump has a multipart housing that includes ahousing part 10 and acover part 12. Between thehousing part 10 and thecover part 12, there is apump chamber 14 that contains a pair ofgears pump chamber 14, thehousing part 10 has tworecesses respective journal journals housing part 10 and extend at least approximately parallel to each other. In order to reduce the weight of thehousing part 10, thejournals gear 16 has abore 17 by means of which it is supported on thejournal 24 in rotary fashion. Thegear 18 has abore 19 by means of which it is supported on thejournal 26 in rotary fashion. Thejournals rotation axis respective gears cover part 12 is attached to thehousing part 10, for example by means of a number of screws. Thehousing part 10 and thecover part 12 are preferably comprised of light metal, in particular aluminum. Thegears - The gear pump has a
drive shaft 30 that is supported so that it can rotate in thehousing part 10. Thedrive shaft 30 is positioned at least approximately coaxial to thejournal 24; thehousing part 10 has a bore that continues inside thejournal 24, through which thedrive shaft 30 extends. A corrugated sealing ring is installed between the bore and thedrive shaft 30 in order to seal thehousing part 10. Thedrive shaft 30 is coupled to thegear 16, for example by means of acoupling member 36 situated between the end of thejournal 24 and thecover part 12. During operation of the gear pump, thedrive shaft 30 drives thegear 16 to rotate, which in turn transmits this rotary motion via face gearing to thegear 18, which is likewise provided with face gearing and meshes with thegear 16 on its outer circumference. The tooth engagement of thegears pump chamber 14 into two subregions, a first subregion of which constitutes anintake chamber 40 and a second subregion of which constitutes apressure chamber 42. Theintake chamber 40 is connected topressure chamber 42 by means of adelivery conduit 44 formed respectively between the tooth grooves on the circumference surfaces of thegears pump chamber 14. Theintake chamber 40 andpressure chamber 42 each have a connection opening in the wall of thehousing part 10 or thecover 12 that connects theintake chamber 40 to an intake line, not shown, from the reservoir and connects thepressure chamber 42 via a delivery line, also not shown, to the intake chamber of the high-pressure fuel pump or the fuel injection pump. The connection opening in theintake chamber 40 constitutes an inlet opening 46 and the connection opening in thepressure chamber 42 constitutes an outlet opening 48. - The gear pump has a
pressure limiting valve 50 that is situated in the housing, for example in thehousing part 10. The bottom of therecesses pump chamber 14 have agroove 52 let into them, which extends between thepressure chamber 42 and theintake chamber 40. Thegroove 52 has a length l, a width b, and a depth t. Viewed in the direction of therotation axes gears groove 52 depicted inFIG. 3 extends approximately tangential to thegears groove 52 protrudes beyond theintersecting lines 54 of the top circle Dk of thegears rotation axes gears groove 52 is situated at least approximately in the center between the twogears groove 52 thus constitutes a connecting conduit extending from thepressure chamber 42 to theintake chamber 40. Outside thegroove 52, the bottom of therecesses housing part 10 is spaced slightly apart from the end faces of thegears - A
bore 56 whose diameter d is preferably a little larger than the width b of thegroove 52 is let into the bottom of thegroove 52. Thebore 56 extends at least approximately parallel to therotation axes gears line 58 between therotation axes gears pressure chamber 42. The measurement H is preferably between approximately 2 and 5 mm. Avalve piston 60 that functions as the valve member of thepressure limiting valve 50 is guided so that it can slide in thebore 56. Acompression spring 62, for example in the form of the helical compression spring clamped between thevalve piston 60 and the bottom of thebore 56, presses thevalve piston 60 toward the end surfaces of thegears gears rotation axes valve piston 60 rests against the end surfaces of thegears chamber 64 delimited in thebore 56 by thevalve piston 60 at its rear end oriented away from thegears intake chamber 40 via abore 66 in thehousing part 10. - The pressure prevailing in the
pressure chamber 42 acts on part of the end surface of thevalve piston 60 oriented toward thegears valve piston 60 in opposition to the force exerted on it by thecompression spring 62. If the force of thecompression spring 62 is greater than the force generated by the pressure prevailing in thepressure chamber 42, then thevalve piston 60 rests against the end surfaces of thegears valve piston 60, in cooperation with thegears groove 52 and therefore the connection between thepressure chamber 42 and theintake chamber 40. When the force of thecompression spring 62 presses thevalve piston 60 against the end surfaces of thegears gears pump chamber 14 in the direction of their rotation axes 25, 27, preferably eliminating it completely. This is advantageous particularly when starting the gear pump and when starting the internal combustion engine since the efficiency of the pump is then optimal. Through friction, thevalve piston 60 exerts a braking force on thegears gears - When a predetermined pressure in the
pressure chamber 42 is exceeded, then the force that the pressure exerts on thevalve piston 60 exceeds the force of thecompression spring 62 so that thevalve piston 60 moves in opposition to the force of thecompression spring 62 and lifts away from the end surfaces of thegears groove 52, thus establishing a connection between thepressure chamber 42 and theintake chamber 40 so that fuel can flow out of thepressure chamber 42 into theintake chamber 40, thus limiting the pressure in thepressure chamber 42. The pressure at which thepressure limiting valve 50 opens can be varied by means of the prestressing of thecompression spring 62, the diameter of thevalve piston 60, and the position of thevalve piston 60 in relation to thepressure chamber 42 and therefore the size of the end surface of thevalve piston 60 acted on by the pressure prevailing in thepressure chamber 42. With increasing pressure in thepressure chamber 42, thevalve piston 60 is slid further into thebore 56 so that thevalve piston 60 opens an ever greater through flow cross section in thegroove 52. The maximum through flow cross section that thevalve piston 60 opens in thegroove 52 is preferably great enough to allow the entire fuel quantity delivered by thegears pressure chamber 42 back to theintake chamber 40 when the gear pump is not supposed to deliver any fuel. The cross-sectional area of thegroove 52 that determines the maximum through flow cross section is preferably between 30 and 60 mm2. When thevalve piston 60 travels into thebore 56, it displaces fuel from thechamber 64 into theintake chamber 40 via thebore 66. When thevalve piston 60 travels out from thebore 56, thechamber 64 can be refilled with fuel from theintake chamber 40 via thebore 66. - During operation of the gear pump, pressure pulsations occur due to the changing tooth engagement of the
gears valve piston 60 rests against the end surfaces of thegears valve piston 60 moves out of the way, which clamps and reduces these pressure pulsations. - The gear pump also has a
bypass valve 70 that can open a connection between thepressure chamber 42 and theintake chamber 40 when the pressure in thepressure chamber 42 is less than that in theintake chamber 40. This can be the case particularly after the gear pump has run dry or when it is filled for the first time; thebypass valve 70 makes it possible to fill the gear pump and to bleed air from it. Thebypass valve 70 has avalve member 72; the pressure prevailing in thepressure chamber 42 acts on thisvalve member 72 and pushes it toward avalve seat 74 on thehousing part 10. For example, thevalve member 72 is contained in arecess 76 of thegroove 52 in the region of the groove that protrudes into thepressure chamber 42. Thevalve member 72 can be comprised, for example, of an elastomer and thevalve seat 74 can be embodied in the form of a flat seat. From thevalve seat 74, abore 78 leads into thechamber 64 in thebore 56 behind thevalve piston 60 and thischamber 64 is in turn connected to theintake chamber 40 via thebore 66. Thevalve member 72 is also engaged by aclosing spring 80, which can be embodied, for example, as a prestressed tension spring contained in thebore 78 and engages thevalve member 72 at one end and hooks onto the last coil of thecompression spring 62 at the other end. The closingspring 80 pulls thevalve member 72 toward thevalve seat 74 with a slight force, thus bringing it into contact with thevalve seat 74 when the gear pump is not in operation. During operation of the gear pump, if the pressure in thepressure chamber 42 is lower than the pressure in theintake chamber 40, then thebypass valve 70 opens by virtue of itsvalve member 72 lifting away from thevalve seat 74 so that fuel can travel from theintake chamber 40 directly into thepressure chamber 42 and thepressure chamber 42 is filled with fuel. If, during further operation of the gear pump, the pressure in thepressure chamber 42 increases and is greater than the pressure in theintake chamber 40, then this presses thevalve member 72 against thevalve seat 74 so that thebypass valve 70 closes, thus disconnecting thepressure chamber 42 from theintake chamber 40. - The gear pump is preceded in the fuel line by a
filter 82 embodied in the form of a prefilter through which the fuel aspirated from the reservoir by the gear pump flows. The gear pump is also followed in the fuel line by anadditional filter 83 embodied in the form of a fine filter through which the fuel delivered by the gear pump flows to the high-pressure fuel pump for the fuel injection pump. It is also possible the pump to be provided only with theprefilter 82 upstream of the gear pump and not the fine filter. For example on the side of thehousing part 10 oriented away from thecover part 12, the gear pump has anadditional housing part 84 that has a recess oriented toward thehousing part 10 in which apressure chamber 85 is provided. Thepressure chamber 85 is connected to a region downstream of thefine filter 83 so that the same pressure prevails in thepressure chamber 83 as downstream of thefine filter 83. When only theprefilter 82 is provided, then thepressure chamber 85 is connected to a region downstream of theprefilter 82 so that the same pressure prevails in thepressure chamber 85 as downstream of theprefilter 82 and upstream of the gear pump. - At its end oriented away from the
housing part 10, thepressure chamber 85 in the recess of thehousing part 84 is delimited by a movingwall 86 that is embodied, for example, in the form of a diaphragm. Asleeve 87 in the recess of thehousing part 84 prestresses thediaphragm 86. The middle region of thediaphragm 86 supports arod 88 that protrudes through a bore in thehousing part 10 and rests against thevalve piston 60. Aprestressed spring 89 embodied, for example, in the form of a helical compression spring is contained in the part of the recess in thehousing 84 that thediaphragm 86 separates from thepressure chamber 85. The pressure prevailing in thepressure chamber 85 thus acts on one side of thediaphragm 86 and theprestressed spring 89 acts on the other. When the pressure in thepressure chamber 85 is low, then thespring 89 pushes thediaphragm 86 and with it, therod 88, toward thevalve piston 60, which exerts an additional force on thevalve piston 60 in the closing direction in addition to that of thecompression spring 62. When the pressure in thepressure chamber 85 is high, then thediaphragm 86 and with it, therod 88, is pulled away from thevalve piston 60 counter to the force of thespring 89 so that a lesser force acts on thevalve piston 60 in the closing direction. If thefine filter 83 or theprefilter 82 is slightly soiled, then only a slight pressure loss occurs as the fuel flows through so that a relatively high pressure prevails downstream of the filter. In this case, the high pressure also prevails in thepressure chamber 85 so that the opening motion of thevalve piston 60 is essentially determined by thecompression spring 62. If thefine filter 83 or theprefilter 82 are heavily soiled, then a greater pressure loss occurs as the fuel flows through so that a relatively low pressure prevails downstream of the filter. In this case, a low pressure also prevails in thepressure chamber 85 so that in addition to the force of thecompression spring 62, the force of thespring 89 also acts on thevalve piston 60 in the closing direction and thisvalve piston 60 only opens in the presence of a higher pressure in thepressure chamber 42. The gear pump then generates a correspondingly higher pressure and delivers a greater quantity of fuel, thus compensating for the loss in pressure and quantity due to thefilter 82 and/or 83. - Instead of being embodied as a gear pump, the fluid pump can also be alternatively embodied, for example, as an internal gear pump or as a vane pump in which the
pressure limiting valve 50 can be used to regulate pressure and thepressure chamber 85 can be used to regulate delivery quantity in the same ways as described above.
Claims (21)
1-9. (canceled)
10. In a fluid pump for use in a fuel injection apparatus of an internal combustion engine and having a housing that contains a pump chamber in which at least one rotary driven delivery element is contained, which delivery element delivers fluid to a pressure chamber from an intake chamber connected to a reservoir, and having a pressure limiting valve for limiting the pressure prevailing in the pressure chamber, which valve has a valve piston inside the housing, the valve piston being acted on in the closing direction by a prestressed closing spring and being acted on in the opening direction by the pressure prevailing in the pressure chamber and, when a predetermined pressure in the pressure chamber is exceeded, opens a connecting conduit from the pressure chamber to the intake chamber, and a filter preceding the fluid pump and/or a filter, following the fuel pump, the improvement wherein the fluid pump comprises a pressure chamber having a connection to a region downstream of the preceding filter or a connection to a region downstream of the following filter, and wherein the pressure prevailing in the pressure chamber influences the force on the valve piston in the closing direction in such a way that as the pressure in the pressure chamber decreases, the force on the valve piston in the closing direction increases.
11. The fluid pump according to claim 10 , wherein the pressure chamber is delimited by a moving wall, one side of which is acted on by the pressure prevailing in the pressure chamber and the other side of which is acted on by a prestressed spring that pushes the wall toward the valve piston in its closing direction.
12. The fluid pump according to claim 11 , wherein the moving wall is supported against the valve piston by means of a rod.
13. The fluid pump according to claim 11 , wherein the moving wall is embodied in the form of a diaphragm.
14. The fluid pump according to claim 12 , wherein the moving wall is embodied in the form of a diaphragm.
15. The fluid pump according to claim 10 , wherein the valve piston at least partially delimits the pump chamber in the direction of the rotation axis of the at least one delivery element, wherein the closing spring presses the valve piston against the end surface of the at least one delivery element oriented toward it, which end surface functions as a valve seat, and wherein the pressure prevailing in the pressure chamber acts on at least part of the end surface of the valve piston oriented toward the at least one delivery element.
16. The fluid pump according to claim 11 , wherein the valve piston at least partially delimits the pump chamber in the direction of the rotation axis of the at least one delivery element, wherein the closing spring presses the valve piston against the end surface of the at least one delivery element oriented toward it, which end surface functions as a valve seat, and wherein the pressure prevailing in the pressure chamber acts on at least part of the end surface of the valve piston oriented toward the at least one delivery element.
17. The fluid pump according to claim 12 , wherein the valve piston at least partially delimits the pump chamber in the direction of the rotation axis of the at least one delivery element, wherein the closing spring presses the valve piston against the end surface of the at least one delivery element oriented toward it, which end surface functions as a valve seat, and wherein the pressure prevailing in the pressure chamber acts on at least part of the end surface of the valve piston oriented toward the at least one delivery element.
18. The fluid pump according to claim 13 , wherein the valve piston at least partially delimits the pump chamber in the direction of the rotation axis of the at least one delivery element, wherein the closing spring presses the valve piston against the end surface of the at least one delivery element oriented toward it, which end surface functions as a valve seat, and wherein the pressure prevailing in the pressure chamber acts on at least part of the end surface of the valve piston oriented toward the at least one delivery element.
19. The fluid pump according to claim 10 , wherein the connecting conduit between the pressure chamber and the intake chamber is embodied in the form of a groove let into a housing part facing the end surface of the at least one delivery element and the valve piston controls the passage through this groove.
20. The fluid pump according to claim 11 , wherein the connecting conduit between the pressure chamber and the intake chamber is embodied in the form of a groove let into a housing part facing the end surface of the at least one delivery element and the valve piston controls the passage through this groove.
21. The fluid pump according to claim 15 , wherein the connecting conduit between the pressure chamber and the intake chamber is embodied in the form of a groove let into a housing part facing the end surface of the at least one delivery element and the valve piston controls the passage through this groove.
22. The fluid pump according to claim 15 , wherein, as the pressure in the pressure chamber increases, the valve piston opens an ever greater through flow cross section in the connecting conduit.
23. The fluid pump according to claim 15 , wherein the diameter of the valve piston is greater than the width (b) of the connecting conduit.
24. The fluid pump according to claim 22 , wherein the diameter of the valve piston is greater than the width (b) of the connecting conduit.
25. The fluid pump according to claim 10 , wherein the valve piston is guided so that it is able to move in a bore of a housing part, and wherein the intake chamber is connected to a chamber that is delimited in the bore by the rear surface of the valve piston oriented away from the end surface of the at least one delivery element.
26. The fluid pump according to claim 11 , wherein the valve piston is guided so that it is able to move in a bore of a housing part, and wherein the intake chamber is connected to a chamber that is delimited in the bore by the rear surface of the valve piston oriented away from the end surface of the at least one delivery element.
27. The fluid pump according to claim 15 , wherein the valve piston is guided so that it is able to move in a bore of a housing part, and wherein the intake chamber is connected to a chamber that is delimited in the bore by the rear surface of the valve piston oriented away from the end surface of the at least one delivery element.
28. The fluid pump according to claim 19 , wherein the valve piston is guided so that it is able to move in a bore of a housing part, and wherein the intake chamber is connected to a chamber that is delimited in the bore by the rear surface of the valve piston oriented away from the end surface of the at least one delivery element.
29. The fluid pump according to claim 22 , wherein the valve piston is guided so that it is able to move in a bore of a housing part, and wherein the intake chamber is connected to a chamber that is delimited in the bore by the rear surface of the valve piston oriented away from the end surface of the at least one delivery element.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE10337849A DE10337849A1 (en) | 2003-08-18 | 2003-08-18 | liquid pump |
DE10337849.9 | 2003-08-18 | ||
PCT/DE2004/001719 WO2005017361A1 (en) | 2003-08-18 | 2004-07-30 | Liquid pump |
Publications (1)
Publication Number | Publication Date |
---|---|
US20060228230A1 true US20060228230A1 (en) | 2006-10-12 |
Family
ID=34177666
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/568,812 Abandoned US20060228230A1 (en) | 2003-08-18 | 2004-07-30 | Liquid pump |
Country Status (5)
Country | Link |
---|---|
US (1) | US20060228230A1 (en) |
EP (1) | EP1658438B1 (en) |
JP (1) | JP4164094B2 (en) |
DE (2) | DE10337849A1 (en) |
WO (1) | WO2005017361A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2017084633A1 (en) * | 2015-11-20 | 2017-05-26 | 苏州宝时得电动工具有限公司 | Pump unit and handheld high-pressure cleaning machine |
WO2020047804A1 (en) * | 2018-09-06 | 2020-03-12 | 苏州宝时得电动工具有限公司 | Hand-held high pressure cleaner |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7640919B1 (en) * | 2008-01-31 | 2010-01-05 | Perkins Engines Company Limited | Fuel system for protecting a fuel filter |
ITBO20090386A1 (en) * | 2009-06-15 | 2010-12-16 | Cnh Italia Spa | FIXED DISPLACEMENT PUMP |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2636440A (en) * | 1949-07-25 | 1953-04-28 | Waukesha Foundry Co | Sanitary pump with infinitely variable output |
US4740140A (en) * | 1985-12-11 | 1988-04-26 | Sundstrand Corporation | Pump having integral switch and bypass valve |
US6095763A (en) * | 1996-06-26 | 2000-08-01 | Robert Bosch Gmbh | Fuel delivery pump with a bypass valve, for a fuel injection pump for an internal combustion engine |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB750673A (en) * | 1953-06-26 | 1956-06-20 | Zenith Carburateur Soc Du | Improvements in or relating to gear pumps and applications thereof |
GB1168489A (en) * | 1966-12-09 | 1969-10-29 | Frederick Arthur Driver | Fuel Supply Systems of Fuel-Injection Pumps of Internal Combustion Engines and of Oil Burners |
DE4224973C2 (en) * | 1992-07-29 | 1995-08-03 | Glyco Metall Werke | Fluid supply system with pressure limitation |
-
2003
- 2003-08-18 DE DE10337849A patent/DE10337849A1/en not_active Withdrawn
-
2004
- 2004-07-30 JP JP2005518302A patent/JP4164094B2/en not_active Expired - Fee Related
- 2004-07-30 WO PCT/DE2004/001719 patent/WO2005017361A1/en active IP Right Grant
- 2004-07-30 US US10/568,812 patent/US20060228230A1/en not_active Abandoned
- 2004-07-30 DE DE502004006939T patent/DE502004006939D1/en active Active
- 2004-07-30 EP EP04762564A patent/EP1658438B1/en not_active Expired - Fee Related
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2636440A (en) * | 1949-07-25 | 1953-04-28 | Waukesha Foundry Co | Sanitary pump with infinitely variable output |
US4740140A (en) * | 1985-12-11 | 1988-04-26 | Sundstrand Corporation | Pump having integral switch and bypass valve |
US6095763A (en) * | 1996-06-26 | 2000-08-01 | Robert Bosch Gmbh | Fuel delivery pump with a bypass valve, for a fuel injection pump for an internal combustion engine |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2017084633A1 (en) * | 2015-11-20 | 2017-05-26 | 苏州宝时得电动工具有限公司 | Pump unit and handheld high-pressure cleaning machine |
US10968899B2 (en) | 2015-11-20 | 2021-04-06 | Positec Power Tools (Suzhou) Co., Ltd. | Pump unit and handheld high pressure washer |
USRE49589E1 (en) | 2015-11-20 | 2023-07-25 | Positec Power Tools (Suzhou) Co., Ltd | Pump unit and handheld high pressure washer |
WO2020047804A1 (en) * | 2018-09-06 | 2020-03-12 | 苏州宝时得电动工具有限公司 | Hand-held high pressure cleaner |
JP2020534990A (en) * | 2018-09-06 | 2020-12-03 | ▲蘇▼州宝▲時▼得▲電▼▲動▼工具有限公司 | Handheld high pressure washer |
Also Published As
Publication number | Publication date |
---|---|
EP1658438A1 (en) | 2006-05-24 |
EP1658438B1 (en) | 2008-04-23 |
JP2006515042A (en) | 2006-05-18 |
JP4164094B2 (en) | 2008-10-08 |
DE10337849A1 (en) | 2005-03-17 |
DE502004006939D1 (en) | 2008-06-05 |
WO2005017361A1 (en) | 2005-02-24 |
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Legal Events
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AS | Assignment |
Owner name: ROBERT BOSCH GMBH, GERMANY Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:BODZAK, STANISLAW;REEL/FRAME:018029/0089 Effective date: 20050721 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |