Classifications

• • 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
  • F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
  • F02M59/02—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps of reciprocating-piston or reciprocating-cylinder type
  • F02M59/04—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps of reciprocating-piston or reciprocating-cylinder type characterised by special arrangement of cylinders with respect to piston-driving shaft, e.g. arranged parallel to that shaft or swash-plate type pumps
  • F02M59/06—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps of reciprocating-piston or reciprocating-cylinder type characterised by special arrangement of cylinders with respect to piston-driving shaft, e.g. arranged parallel to that shaft or swash-plate type pumps with cylinders arranged radially to driving shaft, e.g. in V or star arrangement
• • 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
  • F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
  • F02M59/44—Details, components parts, or accessories not provided for in, or of interest apart from, the apparatus of groups F02M59/02 - F02M59/42; Pumps having transducers, e.g. to measure displacement of pump rack or piston
  • F02M59/445—Selection of particular materials
• • 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
  • F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
  • F02M59/44—Details, components parts, or accessories not provided for in, or of interest apart from, the apparatus of groups F02M59/02 - F02M59/42; Pumps having transducers, e.g. to measure displacement of pump rack or piston
  • F02M59/48—Assembling; Disassembling; Replacing

Definitions

• Low pressure unit for a pump in particular a high-pressure fuel pump of a fuel injection device
• the invention is based on a low-pressure unit for a pump, in particular a high-pressure fuel pump of a fuel injection device, according to the preamble of claim 1.
• Such a low-pressure unit is known from DE 10 2007 057 503 AI.
• This low-pressure unit has a housing in which a delivery quantity measuring device is accommodated, by means of which the amount of fuel sucked in and delivered by the pump can be variably adjusted.
• an overflow valve is also arranged, can be controlled by the excess fuel in a return.
• connecting channels are formed between an opening into the housing inlet and the metering device, the inlet and the overflow valve, between the metering device and a drain to the suction side of the pump and between the spill valve and a return, which opens into the housing.
• the low-pressure unit according to the invention with the features according to claim 1 has the advantage that the metering device completely into the Housing is integrated and no additional housing parts are required for this. As a result, the low-pressure unit is simple and inexpensive to produce with a compact size.
• FIG. 1 shows a pump in a simplified representation in a longitudinal section with a low-pressure unit assigned thereto and
• FIG. 2 shows the low-pressure unit in an enlarged illustration in a section along line II-II in FIG.
• FIG. 1 shows a pump which is in particular a high-pressure fuel pump for a fuel injection device of an internal combustion engine.
• the pump has a housing 10, which may be designed in several parts and in which a rotationally driven drive shaft 12 is rotatably mounted about a rotation axis 13.
• the drive shaft 12 has at least one cam 14.
• the pump has at least one or more pump elements 16, each with a pump piston 18 which is driven by the cam 14 of the drive shaft 12 at least indirectly in a lifting movement in at least approximately radial direction to the rotation axis 13 of the drive shaft 12.
• the pump piston 18 can, for example, be supported on the cam 14 of the drive shaft 12 by means of a roller tappet 20, wherein in the roller tappet 20 a cam 14 on the cam 14 is supported.
• rolling roller 22 is rotatably mounted.
• the drive shaft 12 with its bearing and the roller tappet 20 form a drive region of the pump, which is arranged in an inner space 24 of the housing 10.
• the pump piston 18 is guided in a cylinder bore 26 of a housing part of the pump and limited in this one pump working chamber 28 which is connected via an inlet valve 30 with a low pressure inlet to the pump and an outlet valve 32 with a high pressure drain, which leads, for example, to a high pressure accumulator 34.
• the pump is associated with a low pressure unit 36 which has a separate housing 38 and which is hydraulically and mechanically connected to the pump.
• the material of which the housing 38 of the low pressure unit 36 is made for example, be plastic, wherein the housing 38 is made by injection molding. Alternatively, the material of the housing 38 of the low pressure unit 36 may also be aluminum or a light metal alloy, the housing 38 being made by a casting process.
• the low-pressure unit 36 shown in detail in FIG. 2 has a delivery-quantity measuring device 40 accommodated in the housing 38, by means of which the amount of fuel supplied to the suction side, that is to say the at least one inlet valve 30 of the pump, can be set variably.
• the metering device 40 is embodied as an electromagnetically actuated valve and has an approximately hollow-cylindrical magnet coil 42, a cup-shaped magnet sleeve 44 surrounding it and a disc-shaped magnet core 46 covering the open end of the magnet sleeve 44.
• a movable armature 48 is arranged, which is movable in the direction of the longitudinal axis 43 of the magnetic coil 42 as a function of the energization of the magnetic coil 42.
• the armature 48 has a rod 50 on which a cylindrical body 52 of magnetic or magnetizable material is arranged in the region of the magnet coil 42.
• the rod 50 is displaceably mounted on the one hand in a bearing bush 53 in the bottom of the magnet sleeve 44 and on the other hand in a bearing bush 54 in the magnet core 46.
• the rod 50 projects through the bearing bushing 54 out of the magnetic core 46 on its side facing away from the magnetic coil 42.
• the magnet sleeve 44 with the parts arranged in this magnet coil 42 and armature 48 is molded directly with the material of the housing 38 or surrounded. Electrical connections 41 of the magnetic coil 42 are through the material of the housing 38 to the outside guided and can be connected there with plug contacts, can be connected via the electrical lines.
• the rod 50 rests with its end projecting on the magnetic core 46 against a valve member 56 of the metering device 40.
• the valve member 56 is displaceably guided in a guide sleeve 57 which is arranged in the housing 38 and is overmolded or encapsulated by the material of the housing 38.
• the valve member 56 is pot-shaped, wherein the open end of the rod 50 faces away and the rod 50 rests against the bottom of the valve member 56.
• the guide sleeve 57 is surrounded by a circumferential annular groove 58 and has in the region of the annular groove 58 in its circumference at least one or more openings 59.
• the valve member 56 has in its periphery at least one or more control openings 60 which cooperate with the openings 59 of the guide sleeve 57 and determine a flow cross-section of the metering unit 40.
• the annular groove 58 is connected via a trained in the housing 38 drain passage 62 with the at least one inlet valve 30 of the pump and thus the suction side of the pump.
• the openings 59 of the guide sleeve 57 and the control openings 60 of the valve member 56 may be arbitrarily shaped to release depending on the stroke position of the valve member 56, a flow area of defined size.
• the guide sleeve 57 is made of a material which has at least approximately the same thermal expansion coefficient as the valve member 56. This ensures that when the temperature changes, the clearance between the valve member 56 and the guide sleeve 57 remains at least approximately constant.
• the valve member 56 and the guide sleeve 57 may for example be made of metal, in particular steel or aluminum.
• the housing 38 has an opening 63 which is at least approximately coaxial with the guide sleeve 57 and opens on the outside of the housing 38 on the side of the valve member 56 facing away from the armature 48 and which is closed by means of a closure element 64.
• a spring 66 is clamped between its bottom and an inserted into the guide sleeve 57, for example, in this pressed-in support member 65.
• the support member 65 is annular and has a central opening. By the spring 66, the valve member 56 is held in contact with the rod 50.
• the valve member 56, the spring 66 and the support member 65 are inserted through the opening 63 in the housing 38 and then the Opening 63 closed with the closure element 64. Between the opening 63 in the housing 38 and the closure element 64, at least one sealing element can be clamped.
• an inlet channel 67 in which, for example, fuel is supplied by a feed pump. Fuel from the inlet channel 67 passes via a connecting channel 68 through the opening in the support member 65 into the interior of the valve member 56 and from this via the through the control holes 60 in the valve member 56 and the openings 59 in the guide sleeve 57 defined flow cross-section to the suction side of the pump. From the inlet channel 67 also performs a connecting channel 69 to a arranged in the housing 38 relief valve 70 from. By the overflow valve 70 excess fuel, which is supplied to the inlet channel 68, but is not transmitted through the metering device 40 to the suction side of the pump, is diverted into a return channel 71.
• the overflow valve 70 is designed as a pressure valve and has a counter to the force of a closing spring 72 in the opening direction movable valve member 73.
• a molded by the material of the housing 38 or encapsulated guide sleeve 74 is provided in the housing 38.
• the guide sleeve 74 is made of a material which has at least approximately the same thermal expansion coefficient as the valve member 73. This ensures that when the temperature changes, the clearance between the valve member 73 and the guide sleeve 74 remains at least approximately constant.
• the valve member 73 and the guide sleeve 74 may be made of metal, in particular steel or aluminum, for example.
• the guide sleeve 74 has in its periphery at least one, preferably a plurality of openings 75 which are surrounded by an annular groove 76, wherein the annular groove 76 is connected to the return channel 71.
• the valve member 73 is piston-shaped and at the end of a control edge 77 is formed. When the valve member 73 completely covers the openings 75 of the guide sleeve 74, the overflow valve 70 is closed and no fuel flows from the inlet channel 68 into the return channel 71.
• the valve member 73 When the pressure in the inlet channel 68 and in the connecting channel 69 reaches the opening pressure of the overflow valve 70, the valve member 73 is moved in the guide sleeve 74 against the force of the closing spring 72 and releases with its control edge 77, the openings 75 in the guide sleeve 74, so that fuel from the inlet channel 68 via the Connecting passage 69 and the openings 75 can flow into the return passage 71.
• the housing 38 has an opening 78 which is at least approximately coaxial with the guide sleeve 74 and which opens on the outside of the housing 38 on the side of the valve member 73 facing away from the connecting channel 69 and which is closed by means of a closure element 79.
• the closing spring 72 is arranged between the closure element 79 or a separate support element 80 and the valve member 73.
• the valve member 73, the closing spring 72 and, if appropriate, the support element 80 are inserted through the opening 78 into the housing 38 and then the opening 78 is closed with the closure element 79. Between the opening 78 in the housing 38 and the closure element 79, at least one sealing element can be clamped.
• a throttle point 82 may be provided, which is preferably formed by a molded from the material of the housing 38 or encapsulated throttle element having a throttle opening with a defined cross-section. It can also be provided that between the drainage channel 62 and the return channel 71, a bypass connection is present, in which a throttle point 84 is arranged.
• the throttle body 84 is preferably formed by a molded from the material of the housing 38 or encapsulated throttle element having a throttle opening with a defined cross-section.
• the valve member 56 of the metering device 40 with its control openings 60 forms with the guide sleeve 57 and its openings 59 a slide valve, in which even in the closed position of the valve member 56, in which the control openings 60 do not overlap with the openings 59 of the guide sleeve 57, a Leakage of fuel from the inlet channel 68 may occur to the drainage channel 62.
• the throttle element 84 ensures that this leakage flows into the return passage 71 and does not pass through the drain passage 62 to the suction side of the pump.
• the throttle element 84 as shown in dashed lines in Figure 2 between a cavity 85 of the housing 38, in which the valve member 56 of the metering device 40 immersed in its stroke in the closing direction, and the return passage 71 is arranged.
• the control ports 60 are no longer in Cover with the openings 59 of the guide sleeve 57 and project out of the guide sleeve 57 into the cavity 85.
• a connection of the inlet channel 67 via the throttle element 84 with the return channel 71 is present, so that no Leakage is present in the drainage channel 62.
• one or more fastening tabs 88 may be integrally formed with openings 89, via which the low-pressure unit 36 may be fastened, for example by means of screws on the housing 10 of the pump.
• the low pressure unit 36 may be used on different types of pumps if they have the required standardized ports for the drainage channel 62 and the branched channel 86.

Landscapes

• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Fuel-Injection Apparatus (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=47297239

Family Applications (1)

Country Status (3)

Cited By (1)

Families Citing this family (8)

Citations (3)

Family Cites Families (2)

• 2011
  • 2011-12-05 DE DE201110087701 patent/DE102011087701A1/de not_active Withdrawn
• 2012
  • 2012-12-03 CN CN201280059940.7A patent/CN103975159B/zh not_active Expired - Fee Related
  • 2012-12-03 WO PCT/EP2012/074236 patent/WO2013083517A1/de active Application Filing

Patent Citations (3)

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