WO2012072460A1 - Metering unit and high pressure pump - Google Patents

Metering unit and high pressure pump

Info

Publication number
WO2012072460A1
WO2012072460A1 PCT/EP2011/070761 EP2011070761W WO2012072460A1 WO 2012072460 A1 WO2012072460 A1 WO 2012072460A1 EP 2011070761 W EP2011070761 W EP 2011070761W WO 2012072460 A1 WO2012072460 A1 WO 2012072460A1
Authority
WO
Grant status
Application
Patent type
Prior art keywords
valve
metering
fuel
piston
pump
Prior art date
Application number
PCT/EP2011/070761
Other languages
German (de)
French (fr)
Inventor
Sascha Ambrock
Tobias Landenberger
Original Assignee
Robert Bosch Gmbh
Priority date (The priority date 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 date listed.)
Filing date
Publication date

Links

Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02MSUPPLYING COMBUSTION ENGINES IN GENERAL, WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M59/00Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 - F02M57/00, e.g. rotary cylinder-block type pumps
    • F02M59/20Varying fuel delivery in quantity or timing
    • F02M59/36Varying fuel delivery in quantity or timing by variably-timed valves controlling fuel passages to pumping elements or overflow passages
    • F02M59/366Valves being actuated electrically
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02MSUPPLYING COMBUSTION ENGINES IN GENERAL, WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M63/00Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
    • F02M63/0012Valves
    • F02M63/0031Valves characterized by the type of valves, e.g. special valve member details, valve seat details, valve housing details
    • F02M63/004Sliding valves, e.g. spool valves, i.e. whereby the closing member has a sliding movement along a seat for opening and closing
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02MSUPPLYING COMBUSTION ENGINES IN GENERAL, WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M2200/00Details of fuel-injection apparatus, not otherwise provided for
    • F02M2200/02Fuel-injection apparatus having means for reducing wear
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02MSUPPLYING COMBUSTION ENGINES IN GENERAL, WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M2200/00Details of fuel-injection apparatus, not otherwise provided for
    • F02M2200/90Selection of particular materials
    • F02M2200/9038Coatings

Abstract

The invention relates to a metering unit for a high pressure pump of a fuel injection system of an internal combustion engine, in particular of a common-rail system, which metering unit comprises a solenoid valve which has a solenoid core of hollow-cylindrical configuration in at least one section, wherein a valve piston which is actuated by magnetic force is arranged in the section of hollow-cylindrical configuration, which valve piston can be moved to and fro in the section of hollow-cylindrical configuration, in order to open a throughflow cross section in accordance with its position, wherein the valve piston is provided at least partially with a wear-reducing, hard and/or corrosion-resistant coating. Moreover, the invention relates to a high pressure pump for a fuel injection system, in particular for a common-rail system, of an internal combustion engine, wherein the high pressure pump is provided with a metering unit.

Description

Description Title

Metering and high pressure pump

The present invention relates to a metering device for a high pressure pump of a fuel injection system, in particular a common-rail system of an internal combustion engine according to the preamble of claim 1 and a high pressure pump according to the preamble of claim 8.

State of the art

In the prior art, fuel injection systems, for. known as common rail systems, having a radial piston pump for supplying fuel under high pressure to a fuel reservoir. In order to improve the energy efficiency of such a radial piston pump, takes place in the prior art, a fuel inlet side (suction side) flow control, wherein the current flowing in the pump elements of the radial piston pump, fuel is metered through an attached to the radial piston pump metering unit (ZME). Such a metering unit includes, for example, an infinitely variable solenoid valve that adjusts the pumped into the high pressure storage fuel quantity to the system needs.

A radial piston pump for a fuel injection system of an internal combustion engine, having a metering unit for the flow control, which is arranged in a distributor element is known from DE 10 2007 057 503 A1.

In addition, as described in DE 198 01 355 B4 a high pressure pump for fuel high pressure generation in a common-rail injection system, in which a metering unit is integrated for the total fuel flow, which ensures that only a preselected flow rate in the high pressure pump is subjected to high pressure. When using critical fuels, such as fuels with poor lubricity, low vapor pressure, or water-containing fuel, is formed between the valve piston of the metering unit and a Überströmventilträger known from the prior art configurations, increased wear.

In addition, the metering unit can be so stiff that a volume control is no longer possible, resulting in an unwanted emergency operating mode and / or a breaking down of the motor vehicle result by appearing at the valve piston surface corrosion.

Therefore, it is necessary to create a metering unit for a fuel injection system of an internal combustion engine, in particular for a common rail system, is reduced in wear and corrosion is avoided on the valve piston.

DISCLOSURE OF THE INVENTION Advantages of the Invention

According to the invention, a metering unit for a high-pressure pump of a fuel injection system of an internal combustion engine, in particular a com- mon-rail system, provided, comprising a solenoid valve having an on at least a hollow cylinder a portion formed magnetic core, wherein in the hollow cylindrical portion, a magnetic force operated , valve piston which is arranged back and forth in the hollow cylindrical portion and being reciprocally movable in order to release a flow cross-section according to its position, the piston being at least partially provided with a wear-reducing hard and / or a corrosion resistant coating. Wear on the valve piston surface and the magnet core by providing the coating on the piston in the region of the hollow cylindrical portion, in which is arranged the valve piston, effectively avoided. In addition, also corrosion on the valve piston and thus a failure of the metering unit can be reliably avoided. According to a preferred embodiment, the coating on an outer periphery of the valve piston, in particular on the valve piston skirt surface, is provided. By providing a protective layer on the surface Ventilkolbenmantelflä- both the valve piston and the thus effectively protected against wear in the area of ​​the hollow cylindrical section with this in contact magnetic core are.

Preferably, the protective layer is a nickel-chromium protective layer having a thickness of 3-4 μηι. However, it is also possible to provide a carbon-wear protection coating according to another embodiment having a thickness of about 4 μηι. Other materials which can be used for the protective layer, for example PTFE, as well as MoS 2 and graphite-containing friction coatings such. B. MnPh.

According to yet a preferred embodiment is provided on an inner periphery of the valve piston the coating. In this way an effective protection in the area of ​​contact between the valve piston inner surface and said spring received therein is provided.

According to a further preferred embodiment, the solenoid valve is a proportional valve.

Preferably, the valve piston is designed as a hollow cylinder.

in yet another preferred embodiment, in the hollow-cylindrical valve piston Moreover, a spring, in particular a helical spring arranged. It is also preferred that the metering unit is attachable to the high-pressure pump, in particular screwed.

According to the invention further comprises a high-pressure pump for a fuel injection system, in particular for a common rail system, a Brennkraftma- machine is provided, wherein the high pressure pump is provided with a metering unit according to the above embodiments. With the metering device equipped with the high-pressure pump, a reliable operation of the internal combustion engine is guaranteed.

Brief Description of Drawings

In the following, embodiments of the invention are described with reference to the accompanying drawings in detail. It shows:

Figure 1 is a schematic representation of a fuel injection system according to the prior art.

Figure 2 is a sectional view through a metering unit according to the prior art; FIG. and

Fig. 3 is an exploded view of a magnetic core of a metering unit according to an embodiment.

Embodiments of the invention

In Fig. 1 is a schematic representation of a fuel injection system 1 according to the prior art is shown. From a fuel tank 2 4 fuel is pumped to a high pressure pump 5 via a fuel pump 3 through a fuel line, which is formed here as a radial piston pump. The fuel injection system 1 further comprises a metering unit 6, and a high-pressure accumulator 7, which is also referred to as a rail, which in turn is connected to not shown fuel injectors that inject fuel into a likewise not shown combustion chamber of an internal combustion engine. The metering unit 6 serves to adjust the flow of fuel from the fuel supply pump 3 to the high pressure pump 5 supplies dependent variable. By the metering unit 6 while a variable flow cross-section between the fuel supply pump 3 and the high-pressure pump 5 is set to allow an adjustment of the delivered by the high pressure pump 5 into the high-pressure accumulator 7 fuel amount to the demand of the internal combustion engine. In the supply line to the metering unit 6 of the fuel feed pump 3, an overflow valve 8 is arranged, which serves to much supported by the fuel feed pump 3 fuel which can be wholly or partially closed metering unit 6 does not reach the high-pressure pump 5, abzusteuern and the return line 9 due to the fuel tank. 2 The fuel feed pump 3, the metering device 6 and the spill valve 8 are assigned to a NIE derdruckkreislauf of the fuel injection. 1 The high pressure pump 5 and the high-pressure accumulator 7, however, are assigned to a high-pressure circuit.

In Fig. 2 a sectional view is shown by a metering unit 6 according to the prior art having an infinitely variable solenoid valve 10, a fuel supply-side or suction-side flow control of the fuel supply to a high pressure pump (see Fig. 1) to which the metering 6 is attachable, performs. The solenoid valve 10 is disposed in a magnet housing. 11 In the magnet housing 11, a plug 12 is accommodated with an electrical interface in addition, via the solenoid valve 10 can be supplied with power. The solenoid valve 10 fits in a

High-pressure accumulator (see Fig. 1) of the fuel injection quantity of fuel delivered to the power requirement of the fuel injection at. The solenoid valve 10 has a bearing 13, an armature 14 with ram, with a winding bobbin 15, a pot 16, a residual air gap disc 17 and a magnetic core 18. Furthermore, disposed below the armature 14. A valve piston 19 with control slots, which is surrounded by a spring 20th The metering device 6 is sealed by means of a plurality of O-rings 21st The actuation of the solenoid valve 2 is done by means of a PWM signal. Fig. 3 shows an exploded view of a magnetic core 18 of a metering unit 6 according to one embodiment. The magnetic core 18 is formed as a hollow cylinder at a lower portion 22nd In the hollow cylindrical portion 22 of the actuable by magnetic force the valve piston 19 is accommodated, which therein is reciprocally movable to cross-section a flow according to its position, or release the openings formed by the inflow holes 23, so that fuel (in the metering 6 see Fig. 2 may occur). The valve piston 19 is also formed as a hollow cylinder, so that the spring 20 is receivable therein. A plurality of O-rings 26 for sealing the magnetic core 18 and the metering unit 6 (see Fig. 2) disposed on the magnetic core 18. The valve piston 19 according to the embodiment, at its outer periphery 24, which is formed by the valve piston skirt surface 25, provided with a wear-reducing hard and a corrosion-resistant coating 26th The wear caused by the reciprocating movement of the valve piston 19 in the hollow cylindrical portion 22 of the magnetic core 18 is significantly reduced. Also, by preventing corrosion on the coated surface of optimum and fault-free operation of the metering unit 6 (see FIG. 2) is ensured. In addition, the valve piston 19 also may be provided at its inner periphery 27 with the coating 26, so that protection in the contact region of the spring 20 with the inner periphery 27 is provided.

a metering unit 6 is provided Overall, the inventive configuration, which is particularly robust and can therefore ensure a reliable operation of a high-pressure pump 5 in a fuel injection. 1

Claims

claims
Metering unit (6) for a high pressure pump (5) of a fuel injection system (1), in particular a common-rail system of an internal combustion engine, comprising a solenoid valve (10), which magnet core comprises at at least one portion (22) hollow cylindrical (18) , wherein in the hollow cylindrical portion (22) operated by magnetic force valve piston (19) is arranged, which in the hollow cylindrical portion (22) reciprocally movable forth to release according to its position a flow cross-section, characterized in that
the valve piston (19) is at least partially provided with a wear-reducing hard and / or a corrosion resistant coating (26).
Metering unit (6) according to claim 1,
characterized, in that
the coating (26) on an outer periphery (24) of the valve piston (19), in particular on the valve piston surface (25) is provided.
Metering unit (6) according to claim 1 or 2,
characterized, in that
the coating (26) on an inner circumference (27) of the valve piston (19) is provided.
Metering unit (6) according to one or more of claims 1 to 3, characterized in that.
the solenoid valve (10) is a proportional valve.
Metering unit (6) according to one or more of claims 1 to 4, characterized in that
the valve piston (19) is designed as a hollow cylinder
6. metering unit (6) according to claim 5,
characterized, in that
in the hollow-cylindrical valve piston (19) is arranged a spring (20), in particular a helical spring.
7. metering unit (6) according to one or more of claims 1 to 6,
characterized, in that
the metering unit (6) attachable to the high pressure pump (5), is in particular screwed.
8. metering unit (6) according to one or more of claims 1 to 7,
characterized, in that
the protective layer comprises a chromium-nickel protective layer or a carbon is wear-resistant layer having a thickness in a range of 3 to 4 pm.
9. The high-pressure pump (5) for a fuel injection system (1), in particular for a common rail system of an internal combustion engine,
characterized, in that
is provided the high-pressure pump (5) with a metering unit (6) according to one or more of claims 1 to. 8
PCT/EP2011/070761 2010-11-30 2011-11-23 Metering unit and high pressure pump WO2012072460A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
DE201010062169 DE102010062169A1 (en) 2010-11-30 2010-11-30 Metering and high pressure pump
DE102010062169.2 2010-11-30

Publications (1)

Publication Number Publication Date
WO2012072460A1 true true WO2012072460A1 (en) 2012-06-07

Family

ID=45002975

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2011/070761 WO2012072460A1 (en) 2010-11-30 2011-11-23 Metering unit and high pressure pump

Country Status (2)

Country Link
DE (1) DE102010062169A1 (en)
WO (1) WO2012072460A1 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102014201387A1 (en) 2014-01-27 2015-07-30 Robert Bosch Gmbh Electromagnetically actuable valve for a high pressure pump and high pressure pump
DE102014220222A1 (en) 2014-10-07 2016-04-07 Robert Bosch Gmbh Electromagnetically actuated proportional valve

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19801355B4 (en) 1998-01-16 2004-04-08 Robert Bosch Gmbh High-pressure pump to the fuel supply in fuel injection systems of internal combustion engines
EP1852603A1 (en) * 2004-09-24 2007-11-07 Denso Corporation Flow control valve
US20080152491A1 (en) * 2006-12-26 2008-06-26 Davies Lucy V Coatings for use in fuel system components
DE102007057503A1 (en) 2007-11-29 2009-06-04 Robert Bosch Gmbh Radial piston pump for providing high pressure fuel supply in common rail injection system of internal-combustion engine, has low pressure channel provided in distributor element, where channel hydraulically connects pump element with inlet
WO2009074457A1 (en) * 2007-12-12 2009-06-18 Robert Bosch Gmbh Fuel metering device for a high-pressure fuel pump and high-pressure fuel pump

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19801355B4 (en) 1998-01-16 2004-04-08 Robert Bosch Gmbh High-pressure pump to the fuel supply in fuel injection systems of internal combustion engines
EP1852603A1 (en) * 2004-09-24 2007-11-07 Denso Corporation Flow control valve
US20080152491A1 (en) * 2006-12-26 2008-06-26 Davies Lucy V Coatings for use in fuel system components
DE102007057503A1 (en) 2007-11-29 2009-06-04 Robert Bosch Gmbh Radial piston pump for providing high pressure fuel supply in common rail injection system of internal-combustion engine, has low pressure channel provided in distributor element, where channel hydraulically connects pump element with inlet
WO2009074457A1 (en) * 2007-12-12 2009-06-18 Robert Bosch Gmbh Fuel metering device for a high-pressure fuel pump and high-pressure fuel pump

Also Published As

Publication number Publication date Type
DE102010062169A1 (en) 2012-05-31 application

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