SE545024C2 - Fuel injector arrangement for an internal combustion engine and method for operating said arrangement - Google Patents

Fuel injector arrangement for an internal combustion engine and method for operating said arrangement

Info

Publication number
SE545024C2
SE545024C2 SE1951116A SE1951116A SE545024C2 SE 545024 C2 SE545024 C2 SE 545024C2 SE 1951116 A SE1951116 A SE 1951116A SE 1951116 A SE1951116 A SE 1951116A SE 545024 C2 SE545024 C2 SE 545024C2
Authority
SE
Sweden
Prior art keywords
plunger
fuel
armature
nozzle
fuel injector
Prior art date
Application number
SE1951116A
Other languages
Swedish (sv)
Other versions
SE1951116A1 (en
Inventor
Andreas Andersson
Kim Kylstyröm
Original Assignee
Scania Cv Ab
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
Application filed by Scania Cv Ab filed Critical Scania Cv Ab
Priority to SE1951116A priority Critical patent/SE545024C2/en
Priority to DE102020125356.7A priority patent/DE102020125356A1/en
Publication of SE1951116A1 publication Critical patent/SE1951116A1/en
Publication of SE545024C2 publication Critical patent/SE545024C2/en

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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
    • F02M47/00—Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure
    • F02M47/02—Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure of accumulator-injector type, i.e. having fuel pressure of accumulator tending to open, and fuel pressure in other chamber tending to close, injection valves and having means for periodically releasing that closing pressure
    • F02M47/027—Electrically actuated valves draining the chamber to release the closing pressure
    • 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
    • F02M63/00—Other 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
    • F02M63/0003—Fuel-injection apparatus having a cyclically-operated valve for connecting a pressure source, e.g. constant pressure pump or accumulator, to an injection valve held closed mechanically, e.g. by springs, and automatically opened by fuel pressure
    • F02M63/0007—Fuel-injection apparatus having a cyclically-operated valve for connecting a pressure source, e.g. constant pressure pump or accumulator, to an injection valve held closed mechanically, e.g. by springs, and automatically opened by fuel pressure using electrically actuated valves
    • 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
    • F02M55/00—Fuel-injection apparatus characterised by their fuel conduits or their venting means; Arrangements of conduits between fuel tank and pump F02M37/00
    • F02M55/002—Arrangement of leakage or drain conduits in or from injectors
    • 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
    • F02M63/00—Other 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
    • F02M63/0012—Valves
    • F02M63/0014—Valves characterised by the valve actuating means
    • F02M63/0028—Valves characterised by the valve actuating means hydraulic
    • F02M63/0029—Valves characterised by the valve actuating means hydraulic using a pilot valve controlling a hydraulic chamber
    • 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
    • F02M51/00—Fuel-injection apparatus characterised by being operated electrically
    • F02M51/06—Injectors peculiar thereto with means directly operating the valve needle
    • F02M51/061—Injectors peculiar thereto with means directly operating the valve needle using electromagnetic operating means

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

Abstract

The present disclosure relates to a fuel injector arrangement (100) which comprises a fuel injector (24) comprising a valve (114) comprising an electromagnetic actuator (120) moving an armature (123) connected to an armature plunger (123) to provide an open position and a closed position for the valve. A pilot valve (130) is connected to a nozzle plunger (117) arranged to open and/or close injector outlets (140) and being actuated by the movement of the armature plunger (115). The pilot valve (130) is connected with the nozzle plunger via a hydraulic coupling including a first volume (131) associated with the armature plunger (115), a second volume (134) associated with the nozzle plunger (117) and an orifice (132) between the first and second volumes. The armature plunger (115) and the nozzle plunger (117) are arranged in a respective cavity (116; 118) with a match clearance allowing a leakage flow past the match clearance during the movement of the armature plunger (115). The leakage flow is the return flow of the fuel injector.

Description

TECHNICAL FIELD The present disclosure relates to a fuel injector arrangement for an internal combustion engine of a vehicle, a high pressure injection system and a fuel system comprising the high pressure injection system. The present disclosure further relates to a method of operating the fuel injector arrangement as defined in the appended claims. BACKGROUND ART Internal combustion engines, such as diesel engines, are used for example in trucks, buses, passenger cars, motor boats, vessels, ferries and ships. Internal combustion engines of the defined type are also used in industrial engines and/or engine driven industrial robots, power plants such as e.g. electric power plants comprising a diesel generator, and for example in locomotives. Such internal combustion engines are associated with a fuel system adapted to transport fuel from one or more fuel tanks via an injection system comprising one or more fuel injectors to the internal combustion engine. The fuel system comprises one or more fuel pumps, which may be driven electrically or mechanically by the internal combustion engine. The fuel pumps create a fuel flow and pressure to transport the fuel to the injection system. The injection system then supplies fuel to the internal combustion engine at high pressure.
Internal combustion engines may be driven by different fuels, e.g. by diesel. The fuel is supplied to the engine by means of a fuel system comprising an injection system with one or more fuel injectors. When fuel injector is opened, fuel is supplied with high pressure to the injector. All fuel is however not injected to the engine, whereby a return of the fuel back to the fuel tank is normally arranged in the fuel system. The excessive supply of fuel to the injector causes parasitic losses of fuel, which is undesirable. Additionally, diesel often contains particulate matter which may cause wear in the sensitive injectors.
Therefore, there is a need to decrease both parasitic losses in the fuel systems and wear in the fuel injectors.
There have been attempts to provide more durable lifespan for fuel injectors, ofwhich US 2012/0291753 A1 discloses an example.
However, there is still a need for a solution by which both parasitic losses in the fuel systems and wear in the fuel injectors can be decreased. SUMMARY OF THE INVENTION The objective of the present invention is thus to decrease both parasitic losses in the fuel systems and wear in the fuel injectors.
Additionally, it is an objective to prevent operational disturbances in fuel injectors and fuel systems associated with an internal combustion engine. A further objective is to provide a robust fuel injector.
The objectives above are attained with a fuel injector arrangement as defined in the appended claims. Especially, the fuel injector arrangement according to the present invention is associated with an injection system of a fuel system configured to supply fuel from a fuel tank to an internal combustion engine.
The fuel injector arrangement comprises at least one fuel injector comprising an injector body comprising a fuel inlet, at least one injector outlet and a valve comprising an electromagnetic actuator configured to move an armature to provide an open position and a closed position ofthe valve. The armature is associated with an armature plunger, which is associated with a pilot valve. The pilot valve is connected to a nozzle plunger arranged to open and/or close the at least one injector outlet. The nozzle plunger is actuated by the movement ofthe armature plunger. The fuel injector arrangement further comprises a fuel return outlet for returning fuel to the tank. The pilot valve is connected with the nozzle plunger via a hydraulic coupling including a first volume associated with the armature plunger, a second volume associated with the nozzle plunger and an orifice between the first and second volumes. The return outlet is connected to the armature plunger. The armature plunger and the nozzle plunger are arranged in a respective cavity of the injector body with a match clearance allowing a leakage flow past the match clearance when the armature plunger is moved, i.e. moved up and down in the cavity. This leakage flow corresponds to the return flow of the fuel injector. The leakage flow can thus be reduced and the leakage flow past the match clearance may be arranged to be the only return flow from the fuel injector. By this construction, parasitic losses in the fuel systems and wear in the fuel injectors can be decreased. Since less particulate matter, which is present in the fuel, passes through the components of the fuel injector, it is possible to prevent operational disturbances in the fuel injectors and thus in fuel systems associated with an internal combustion engine. By the present valve structure, a robust fuel injector is thus provided.
A surface area of the armature plunger facing the first volume be larger than a surface area of the nozzle plunger facing the second volume. By the hydraulic connection and the different plunger areas, it is possible to obtain a gear ratio for the parts while lifting, i.e. it is possible to lift the armature plunger less than the nozzle plunger. Thus, the valve may be quickly controlled while the nozzle plunger may be positioned in the open/closed position in an accurate manner.
An opening and closing speed and/or force of the valve may be arranged to be controllable. ln this way, smooth operation can be provided.
The opening speed of the nozzle plunger may be arranged to be controllable by means of the size of the orifice. The size of the orifice affects the opening speed of the nozzle plunger.
The opening force of the armature plunger may be arranged to be controllable by means of a preload of a spring connected to the armature. The spring may have a pre- determined spring force adapted to provide the desired opening speed, when a solenoid actuates the armature. Thus, a simple and robust control device for the valve can be provided.
The nozzle plunger may be connected to a spring at a surface facing the orifice. Also this spring may have a pre-determined spring force adapted to provide the desired opening speed, whereby a simple and robust control device for the valve can be provided.
The present invention also relates to a high pressure injection system comprising a high pressure pump, an accumulator and a fuel injector arrangement as described above.
Additionally, the present invention relates to a fuel system configured to supply fuel to an internal combustion engine associated with a vehicle, the fuel system comprising a main fuel pipe connecting a low pressure fuel pump, a fuel tank upstream ofthe low pressure pump, and a high pressure injection system as mentioned above downstream of the low pressure pump.
Furthermore, the present invention relates to a vehicle comprising the fuel system as described above.
Additionally, the present invention relates to a method of operating a fuel injector arrangement associated with an injection system of a fuel system and configured to supply fuel from a fuel tank to an internal combustion engine. The fuel injector arrangement comprises at least one fuel injector comprising an injector body connected to a fuel inlet, at least one injector outlet, and a valve comprising an electromagnetic actuator configured to move an armature to provide an open position and a closed position for the valve, the armature being associated with an armature plunger, which is associated with a pilot valve, the pilot valve being connected to a nozzle plunger arranged to open and/or close the at least one injector outlet, wherein the nozzle plunger is actuated by the movement ofthe armature plunger, the fuel injector further comprising a fuel return outlet for returning fuel from the fuel injector to the tank. The method comprises the following steps: - opening the valve by lifting the nozzle plunger to an open position by lifting the armature plunger by means of an electromagnetic actuator, wherein the armature plunger is connected with the nozzle plunger via a hydraulic coupling of the pilot valve including a first volume associated with the armature plunger, a second volume associated with the nozzle plunger and an orifice between the first and second volumes - during the movement of the armature plunger, leading a leakage flow past a match clearance between the nozzle plunger, the armature plunger and a respective cavity of the injector body, in which the nozzle plunger and the armature plunger are respectively arranged, to the return channel to provide a return flow of the fuel injector, - closing the valve by pushing the nozzle plunger into a closed position by moving the armature plunger towards the outlet openings, the nozzle plunger thereby blocking the outlet openings.
The method may comprise controlling an opening and closing speed and/or force of the valve. The controlling the opening and closing speed may be done by means of controlling the size of the orifice. Furthermore, the method may comprise controlling the opening force by means of controlling a preload of a spring connected to the armature.
Further features and advantages are described below in the detailed description ofthe invention.
BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 schematically illustrates a vehicle comprising a fuel system of the present disclosure; Fig. 2 schematically illustrates an example coupling scheme for the fuel system of the present disclosure; Fig. 3 schematically illustrates an example of a fuel injector according to the present disclosure in an open position Fig. 4 schematically illustrates an example of a fuel injector according to the present disclosure in a closed position.
DETAILED DESCRIPTION The solution ofthe present disclosure will be described in more detail below with reference to the accompanying drawings, which schematically illustrate examples of the present disclosure in a way not limiting the scope defined in the appended claims. The drawings shall not be considered drawn to scale as some features may be exaggerated in order to more clearly illustrate the present solution or features thereof.
Generally, the present disclosure relates to a fuel injector arrangement, which is a part of a high pressure injection system, which may also be referred to as a high pressure circuit in a fuel system of a vehicle. The fuel system may comprise a fuel tank arranged upstream of a low pressure pump, which is arranged to suck fuel from the tank. The low pressure pump is arranged to supply and pressurize fuel further to a high pressure pump, which is arranged downstream of the low pressure pump and associated with the internal combustion engine. Before injecting the fuel to the engine, it is supplied to an accumulator connected to the injection arrangement, which is configured to provide fuel to the internal combustion engine. The low pressure pump pressurizes the fuel to 9-14 bar, but is not limited thereto. The low pressure pump may be mechanically driven by the internal combustion engine or it may be electrically driven. The high pressure pump is associated with and located in close proximity of an engine block ofthe internal combustion engine and is arranged to pressurize the fuel to a high pressure, e.g. to 500- 2400 bar, but is not limited thereto. Thus, the low pressure pump pressurizes the fuel to a pressure, which is more than 10, or more than 20 or more than 30 times smaller than the operating pressure ofthe high pressure pump. Further, the tank, the low pressure pump and the high pressure pump are connected by a main fuel pipe or conduit. The fuel system also usually comprises one or more fuel filters for purifying the fuel from pa rticulate matter and/or water.
Fig. i schematically shovvs a side view of a heavy vehicle Zl, which is a truck, coinprising an internal combustion engine 2, which is associated with a fuel system ii comprâsing a fuel tank 11, Generally, in the present disclosure hesides the vehicle being a truck, the vehicle could be any other type of a heavy vehicle, such as a hus. The vehicle l ttlrther comprises a gearbox 5 connected to the clrivihg vtfheels 10 of the vehicle fi via a propeller shaft S.
Fig. 2 illustrates schematically an example of a fuel system 4, in which the fuel injection arrangement of the present disclosure is used. The fuel system 4 comprises a fuel tank 11 from which fuel is sucked by means of a low pressure pump 12 to a high pressure injection system 25 comprising a high pressure pump 19, which supplies fuel at high pressure to an accumulator 20. The fuel system is further provided with a main fuel pipe 18, which connects the tank 11, the low pressure pump 12 and the high pressure pump 19 ofthe fuel system 4. ln the shown example in Fig. 2, the fuel system also comprises a fuel filter 17 arranged in the main fuel pipe 18 downstream ofthe low pressure pump 12 and upstream of the high pressure pump 19, i.e. on the pressurized side of the low pressure pump 12. A further fuel filter may be provided in the suction side of the low pressure pump 12, i.e. upstream of the low pressure pump and downstream ofthe tank 11. The accumulator 20 may be associated with a fuel return pipe 22, through which fuel not supplied to the engine 2 is returned to the tank The accumulator 20, which can be ofthe type common rail, supplies fuel to fuel injectors 24, which in turn inject fuel to the internal combustion engine 2. To allow any excess fuel to be recirculated back to the tank 11, a return flow pipe 22 comprising a check valvecan be associated with the fuel injectors 24 and/or accumulator 20. ln this way, fuel can be returned back to the fuel tank while the check valve 21 prevents flow back to the fuel injectors/accumulator. The return flow pipe 22 may be directly connected to the tank 11. Alternatively, the return flow pipe may be connected to the main fuel pipe 18 ofthe fuel system.
Generally, in this description by "electromagnetic actuator" is meant an electric device which transforms input energy to output mechanical work. An example of an electromagnetic actuator is a solenoid actuator, which converts an electrical signal into a magnetic field producing motion of a part, e.g. pushing and pulling motion of an armature in a valve.
By "pilot valve" is generally in this description meant a part of the valve positioned between an armature plunger and a nozzle plunger and connecting the same by hydraulic connection to each other. The pilot valve is configured to control the valve feed by means of the hydraulic connection in which only small feeds are involved.
By "match clearance" is meant a distance by which one object clears another or a clear space between them.
Reference is now made to Fig. 3 and Fig. 4 in which an example construction of a fuel injector 24 comprised in a fuel injector arrangement 100 is shown schematically. ln Fig. 3, the valve 24 is in an open position, and in Fig. 4, the valve is in a closed position. The fuel injector arrangement 100 may be associated with the high pressure injection system 25 of a fuel system 4 as illustrated in Fig. 2, which is configured to supply fuel from a fuel tank 11 to an internal combustion engine The fuel injector arrangement 100 comprises at least one fuel injector 24 comprising an injector body 110. The injector body 110 comprises a fuel inlet 111, at least one injector outlet 140, and a valve 114. The valve 114 comprises or is connected to an electromagnetic actuator 120, e.g. a solenoid. The actuator 120 is configured to move an armature 123 up and down in respect to an end stop plate 122 and to provide an open position and a closed position for the valve. The armature 123 is associated with an armature plunger 115, which is associated with a pilot valve 130. The armature 123 responds to an electromagnetic signal from the solenoid and provides a pushing or pulling motion to the armature plunger 115. The armature 123 may be connected to an upper armature end stop 122. ln the shown example, the armature 123 in the form of a plate is connected to a spring 124 positioned in between the armature 123 and the stop 122. The spring 124 may have a pre-determined preload or spring force and can thus provide a desired opening speed for the valve The pilot valve 130 is connected to a nozzle plunger 117 of the valve. The nozzle plunger is arranged to open and/or close at least one injector outlet 140 located in a tip 150 of the injector body 110. ln Fig. 3 the nozzle plunger is not in contact with the injector outlet openings 140, and thus the valve is in an open position and fuel can be injected from the valve as illustrated by the arrows. ln Fig. 4, the valve is in a closed position, in which the nozzle plunger 117 blocks the outlet openings 140 and thus provides a closed position for the valve.
The nozzle plunger 117 is connected to the armature plunger 115 via a hydraulic coupling ofthe pilot valve 130 and is actuated by the movement of the armature plunger 115. The hydraulic coupling includes a first volume 131 associated with the armature plunger 115, a second volume 134 associated with the nozzle plunger 117 and an orifice 132 between the first and second volumes 131, 134. The orifice 132 in the shown example also comprises a channel 133, by which the size or volume of the orifice can be controlled. lt should be noted that the size of the orifice and the channel are exaggerated to more clearly illustrate the example construction. The nozzle plunger 117 is thus configured to provide the open and/or closed position ofthe valve The fuel injector arrangement 100 further comprises the fuel return outlet 112 for returning fuel to the tank 11 shown in Fig. 2. The return outlet 112 is connected to the armature plunger 115. The armature plunger 115 is arranged in a cavity 116 of the injector body 110 with a match clearance, i.e. open space between the armature plunger 115 and walls ofthe cavity 116. ln this way it is possible to allow a leakage flow illustrated by the arrows past the match clearance when the armature plunger is moved up and down in the cavity. ln a similar manner, the nozzle plunger 117 is arranged in a cavity 118 ofthe nozzle body 110 with a match clearance, i.e. open space between the nozzle plunger 117 and walls ofthe cavity 117. Thus, the fuel not injected via the outlet openings 140 is pressed through the match clearances between the nozzle plunger 117 and armature plunger 115 and the respective cavities 118, 116. This leakage flow corresponds to the return flow of the fuel injector. The leakage flow may be arranged to be the only return flow from the fuel injector. Thereby it is possible to substantially decrease the amount of fuel returned to the fuel tank. Thereby, parasitic losses in the fuel systems and wear in the fuel injectors can be decreased. Since there is a decreased amount of fuel returned to the fuel tank, also less particulate matter present in the fuel passes through the components of the fuel injector. Therefore, it is possible to prevent operational disturbances in fuel injectors and thus in fuel systems associated with an internal combustion engine. By the present valve structure, a robust fuel injector is provided.
As schematically illustrated in Fig. 3 and 4, a surface area a1 ofthe armature plunger 115 facing the first volumebe larger than a surface area A2 of the nozzle plunger 134 facing the second volume 134. By the hydraulic connection and the different plunger areas, it is possible to obtain a gear ratio for the parts while lifting, i.e. it is possible to lift the armature plunger 115 less than the nozzle plunger 117. Thus, the valve can be quickly controlled while nozzle plunger may be positioned in the open/closed position in an aCCUFate mafïnef.
An opening and closing speed and/or force of the valve may be arranged to be further controllable. For example, the opening speed of the nozzle plunger 117 may be arranged to be controllable by means of the size or volume ofthe orifice 132, which may include the orifice channel 133. Additionally, to further control the speed, the nozzle plunger 117 may be connected to a spring 135 at a surface facing the orifice 132. The spring 135 may have a pre-determined spring force adapted to provide the desired opening speed, whereby a simple and robust control device for the valve can be provided.
The opening force of the armature plunger 117 may also be arranged to be controllable by means of a preload or spring force of a spring 124 connected to the armature 123. The spring 124 may have a pre-determined spring force adapted to provide the desired opening speed, when a solenoid actuates the armature. Thus, a simple and robust control device for the valve can be provided.
The present disclosure also relates to an injection system 25 comprising the high pressure pump 19, accumulator 20 and fuel injector arrangement 100 as described above.
Additionally, the present disclosure relates to a fuel system 4 illustrated in Fig. 2 configured to supply fuel to an internal combustion engine 2 associated with a vehicle 1, the fuel system comprising a main fuel pipe 18 connecting a low pressure fuel pump 12, a fuel tank 11 upstream of the low pressure pump 12, and a high pressure injection system as described above downstream of the low pressure pump Furthermore, the present invention relates to a vehicle 1 illustrated in Fig. 1 comprising the fuel system 4 as described above.
Additionally, the present invention relates to a method of operating a fuel injector arrangement 100 associated with an injection system 25 of a fuel system 4 and configured to supply fuel from a fuel tank to an internal combustion engine 2. The fuel injector arrangement comprises at least one fuel injector as described above and as illustrated schematically in Fig. 3 and 4. The method comprises opening the valve 114 by lifting the nozzle plunger 117 to an open position by lifting the armature plunger 115 bymeans of an electromagnetic actuator 120. The armature plunger 115 is connected with the nozzle plunger 117 via a hydraulic coupling of the pilot valve 130, the hydraulic coupling including the first volume 131 associated with the armature plunger 115, the second volume 134 associated with the nozzle plunger 117 and an orifice 132 between the first and second volumes 131, The method further comprises leading, during the movement of the armature plunger, a leakage flow past the match clearance between the nozzle plunger 117 and the armature plunger 115 and the respective cavity 118, 116 to the return channel 112 to provide a return flow of the fuel injector.
The method also comprises a step of closing the valve by pushing the nozzle plunger 117 into a closed position, in which the outlet openings 140 are blocked by the nozzle plunger 117. The closed position can be obtained by moving or pushing the armature plunger 115 towards the outlet openings by means of the electromagnetic actuator 120 or by releasing the magnetic force acting on the armature plunger 115 and by letting the spring 124 force the armature plunger 115 downwards. Since the nozzle plunger 117 is hydraulically connected with the armature plunger 115, the nozzle plunger 117 will move by the movement of the armature plunger 115 downwards towards the tip 115 of the injector body 110 and block the outlet openings 140. When the nozzle plunger 117 blocks the outlet openings, the fuel inlet 111 is also blocked and closed. Thus, no fuel is fed to the valve 114. Thereby no return flow is provided in the match clearances 116, 118 and the return outlet 122 can also thus be blocked.
The foregoing description of the examples has been provided for illustration of the present invention. The examples are not intended to limit the scope ofthe invention defined in the appended claims and features from the embodiments may be combined with one another.

Claims (13)

1. A fuel injector arrangement (100) associated with an injection system (25) of a fuel system (4) configured to supply fuel from a fuel tank (11) to an internal combustion engine (2), the fuel injector arrangement (100) comprising at least one fuel injector (24) comprising an injector body (110) comprising a fuel inlet (111), at least one injector outlet (140) and a valve (114) comprising an electromagnetic actuator (120) configured to move an armature (123) to provide an open position and a closed position of the valve (114), the armature (123) being associated with an armature plunger (115), which is associated with a pilot valve (130), the pilot valve being connected to a nozzle plunger (117) arranged to open and/or close the at least one injector outlet (140), wherein the nozzle plunger (117) is actuated by the movement ofthe armature plunger (115), the fuel injector arrangement further comprising a fuel return outlet (112) for returning fuel to the tank (11), characterized in that the pilot valve (130) is connected with the nozzle plunger (117) via a hydraulic coupling such that the nozzle plunger (117) will move by the movement of the armature plunger (115), the hydraulic coupling including a first volume (131) associated with the armature plunger (115), a second volume (134) associated with the nozzle plunger (117) and an orifice (132) between the first and second volumes, wherein a surface area (A1) of the armature plunger (115) facing the first volume (131) is larger than a surface area (A2) of the nozzle plunger (117) facing the second volume (134), whereby it is possible by the hydraulic connection and the different plunger areas to obtain a gear ratio for the parts while lifting, i.e. it is possible to lift the armature plunger less than the nozzle plunger, and wherein the return outlet (112) is connected to the armature plunger (115), the armature plunger (115) and the nozzle plunger (117) being arranged in a respective cavity (116; 118) of the injector body (110) with a match clearance allowing a leakage flow past the match clearance when the armature plunger is moved to provide a return flow ofthe fuel injector (24).
2. Fuel injector arrangement according to claim 1 s; . wherein the leakage flow is arranged to be the only return flow from the fuel injector (24).
3. Fuel injector arrangement according to any one of claims 1 to 2, wherein an opening and closing speed and/or force ofthe valve (114) is arranged to be controllable.
4. Fuel injector arrangement according to any one ofthe preceding claims, wherein the opening speed of the nozzle plunger (117) is arranged to be controllable by means of the size of the orifice (132).
5. Fuel injector arrangement according to any one ofthe preceding claims, wherein the opening force of the armature plunger (115) is arranged to be controllable by means of a preload of a spring (124) connected to the armature (123).
6. Fuel injector arrangement according to any one ofthe preceding claims, wherein the nozzle plunger (117) is connected to a spring (135) at a surface facing the orifice (132).
7. A high pressure injection system (25) comprising a high pressure pump (19), an accumulator (20) and a fuel injector arrangement (100) of any one of claims 1-
8. A fuel system (4) configured to supply fuel to an internal combustion engine (2) associated with a vehicle (1), the fuel system comprising a main fuel pipe (18) connecting a low pressure fuel pump, a fuel tank (11) upstream of the low pressure pump (12), and a high pressure injection system (25) according to claim downstream ofthe low pressure pump (12).
9. Vehicle (1) comprising the fuel system (5) of claim
10. Method of operating a fuel injector arrangement (100) associated with an injection system of a fuel system (4) and configured to supply fuel to an internal combustion engine (2), the fuel injector arrangement (100) comprising at least one fuel injector (24) comprising an injector body (110) comprising a fuel inlet (111), at least one injector outlet (140) and a valve (114) comprising an electromagnetic actuator (120) configured to move an armature (123) to provide an open position and a closed position of the valve, the armature (123) being associated with an armature plunger (115), which is associated with a pilot valve (130), the pilot valve (130) being connected to a nozzle plunger (117) arranged to open and/or close the at least one injector outlet (140), wherein the nozzle plunger (117) is actuated by the movement ofthe armature plunger (115), the fuel injector (24) further comprising a fuel return outlet (112) for returning fuel from the fuel injector (24) to the tank (11), the method s-\:\ steps of - opening the valve (114) by lifting the nozzle plunger (117) to an open position by lifting the armature plunger (115) by means of an electromagnetic actuator (120), wherein the armature plunger (115) is connected with the nozzle plunger (117) via a hydraulic coupling of the pilot valve (130) including a first volume (131) associated with the armature plunger (115), a second volume (134) associated with the nozzle plunger (117) and an orifice (132) between the first and second volumes (131; 134), wherein a surface area (A1) ofthe armature plunger (115) facing the first volume (131) is larger than a surface area (A2) of the nozzle plunger (117) facing the second volume (134), whereby it is possible by the hydraulic connection and the different plunger areas to obtain a gear ratio for the parts while lifting, i.e. it is possible to lift the armature plunger less than the nozzle plunger, - during the movement of the armature plunger (115), leading a leakage flow past a match clearance between the nozzle plunger (117), the armature plunger (115) and a respective cavity (118, 116) of the injector body (110), in which the nozzle plunger (117) and the armature plunger (115) are respectively arranged, to the return channel (112) to provide a return flow of the fuel injector (24), - closing the valve by pushing the nozzle plunger (117) into a closed position by moving ofthe armature plunger (115) towards the outlet openings (140), the nozzle plunger (117) thereby blocking the outlet openings (140). 5
11. Method according to claim 10 comprising controlling an opening and closing speed and/or force ofthe valve (114).
12. Method according to claim 11 comprising controlling the opening and closing 10 speed by means of controlling the size of the orifice (132).
13. Method according to claim 11 or 12 comprising controlling the opening force by means of controlling a preload of a spring (124) connected to the armature (123).
SE1951116A 2019-10-01 2019-10-01 Fuel injector arrangement for an internal combustion engine and method for operating said arrangement SE545024C2 (en)

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SE1951116A SE545024C2 (en) 2019-10-01 2019-10-01 Fuel injector arrangement for an internal combustion engine and method for operating said arrangement
DE102020125356.7A DE102020125356A1 (en) 2019-10-01 2020-09-29 Fuel injection nozzle assembly, high pressure injection system with the injection nozzle assembly, fuel system with the high pressure injection system, vehicle with the fuel system and method for operating the fuel injection nozzle assembly

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SE1951116A SE545024C2 (en) 2019-10-01 2019-10-01 Fuel injector arrangement for an internal combustion engine and method for operating said arrangement

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Citations (9)

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DE19938999A1 (en) * 1999-08-17 2001-03-01 Siemens Ag Fuel injection valve with lubricated mechanical transmission element
WO2001079688A1 (en) * 2000-04-18 2001-10-25 Robert Bosch Gmbh Fuel injection valve for internal combustion engines
USRE37633E1 (en) * 1995-08-29 2002-04-09 Isuzu Motors Limited Accumulating fuel injection apparatus
DE10242686A1 (en) * 2002-09-13 2004-03-25 Robert Bosch Gmbh Fuel injection valve for internal combustion engines comprises a closing spring arranged under pre-tension in a control chamber and loading a valve needle in the closing direction.
EP1923564A2 (en) * 2006-11-16 2008-05-21 Robert Bosch Gmbh Fuel injector
EP2138709A1 (en) * 2008-06-24 2009-12-30 Robert Bosch GmbH Directly actuated fuel injector
EP2481910A1 (en) * 2011-02-01 2012-08-01 Robert Bosch GmbH Fuel injector component
DE102011004031A1 (en) * 2011-02-14 2012-08-16 Continental Automotive Gmbh Injection system, particular common rail injection system for injecting fuel in internal combustion engine, has high-pressure pump and injector, which is hydraulically connected to high pressure pump
WO2016097463A1 (en) * 2014-12-19 2016-06-23 Wärtsilä Finland Oy A fuel injector for an internal combustion piston engine

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
USRE37633E1 (en) * 1995-08-29 2002-04-09 Isuzu Motors Limited Accumulating fuel injection apparatus
DE19938999A1 (en) * 1999-08-17 2001-03-01 Siemens Ag Fuel injection valve with lubricated mechanical transmission element
WO2001079688A1 (en) * 2000-04-18 2001-10-25 Robert Bosch Gmbh Fuel injection valve for internal combustion engines
DE10242686A1 (en) * 2002-09-13 2004-03-25 Robert Bosch Gmbh Fuel injection valve for internal combustion engines comprises a closing spring arranged under pre-tension in a control chamber and loading a valve needle in the closing direction.
EP1923564A2 (en) * 2006-11-16 2008-05-21 Robert Bosch Gmbh Fuel injector
EP2138709A1 (en) * 2008-06-24 2009-12-30 Robert Bosch GmbH Directly actuated fuel injector
EP2481910A1 (en) * 2011-02-01 2012-08-01 Robert Bosch GmbH Fuel injector component
DE102011004031A1 (en) * 2011-02-14 2012-08-16 Continental Automotive Gmbh Injection system, particular common rail injection system for injecting fuel in internal combustion engine, has high-pressure pump and injector, which is hydraulically connected to high pressure pump
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