EP3376016A1 - Control valve of a fuel injector - Google Patents
Control valve of a fuel injector Download PDFInfo
- Publication number
- EP3376016A1 EP3376016A1 EP18165540.8A EP18165540A EP3376016A1 EP 3376016 A1 EP3376016 A1 EP 3376016A1 EP 18165540 A EP18165540 A EP 18165540A EP 3376016 A1 EP3376016 A1 EP 3376016A1
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- EP
- European Patent Office
- Prior art keywords
- face
- valve
- bore
- opening
- sleeve
- 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.)
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Classifications
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- 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
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- 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
- F02M63/007—Details not provided for in, or of interest apart from, the apparatus of the groups F02M63/0014 - F02M63/0059
- F02M63/0071—Details not provided for in, or of interest apart from, the apparatus of the groups F02M63/0014 - F02M63/0059 characterised by guiding or centering means in valves including the absence of any guiding means, e.g. "flying arrangements"
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- 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
- F02M63/007—Details not provided for in, or of interest apart from, the apparatus of the groups F02M63/0014 - F02M63/0059
- F02M63/0078—Valve member details, e.g. special shape, hollow or fuel passages in the valve member
Definitions
- the present invention relates to a fuel injector and more particularly to a control valve.
- Fuel injectors known in the art are provided with control valve controlling the fuel pressure in a control chamber that cooperates with a valve needle in order to enable or forbid fuel spray.
- the control valve comprises a cylindrical body extending axially from an upper face to a lower face and provided with a shallow recess opening in the upper face and from the center of the bottom of which extends toward the lower face a valve bore in which open a high pressure conduit in fluid communication with said control chamber and, a return conduit in fluid communication with a low pressure reservoir.
- a cylindrical sleeve is fixedly arranged in the bore by means of two press fitted annular areas, one being at the upper extremity of the bore, the other being at the lower extremity of the bore. Inside the sleeve is slidably arranged the stem of an armature-stem assembly that cooperates with a coil generating a magnetic field.
- the high pressure conduit laterally opens in the bore, between the press fit annular areas and, the return conduit comprises the shallow recess that creates a low pressure chamber.
- the armature-stem assembly slides between an upper position where it opens a valve seat creating a fluid communication between the high pressure conduit and the return conduit and, a lower position wherein said valve seat is closed.
- the valve seat comprises a fixed face that is an upper face of the sleeve and a mobile face that is a conical face of the stem arranged just under the armature.
- valve of a fuel injector
- said valve being provided with a cylindrical valve body extending along a main axis from an upper face to a lower face.
- the body is provided with a large cylindrical shallow recess opening in said upper face and in the bottom of which opens a valve distributor bore axially extending toward the lower face.
- the control valve is further provided with a magnetic armature-stem assembly, the magnetic armature having a thick disc-shape in the centre of which is enshrined and crimped a cylindrical stem shaft extending perpendicularly from the armature to a lower extremity and, guiding means for slidably guiding the armature-stem assembly into the valve bore and with, seating means, for opening or closing a fluid communication between a high pressure conduit and a return conduit, both conduits opening in said bore.
- the seating means and the guiding means are distinct and independent means.
- the guiding means is a cylindrical sleeve extending from an upper extremity to a lower extremity and fixedly press fitted in the valve bore, the stem being slidably engaged in said sleeve and, the seating means comprises a valve seat having a fixed face surrounding the opening of the return conduit cooperating with a mobile face integral to the stem.
- the sleeve is fixed in the bore by means of a single annular area of interference with the bore.
- the single annular area of interference is a proximal an extremity of the sleeve and the fixed face of the valve seat is proximal the opposite extremity of the sleeve.
- valve bore opens in the lower face of the body, said single annular area of interference being proximal to said lower face and, the valve seat is in the opening of bore in the bottom of the recess, the fixed face being the interconnecting face surrounding the opening of the valve bore in the recess, the mobile face being a conical face of the stem proximal the armature.
- the high pressure conduit laterally opens in the valve bore and the shallow recess is part to the return conduit, the sleeve being provided with radial through holes enabling, in use the high pressure fuel to flow from the high pressure conduit, through the sleeve and into the return conduit.
- valve bore is a through bore opening in the recess and in the lower face of the body, the single annular area of interference being proximal to the recess an, the valve seat is in the opening of bore in the lower face of the valve body, the mobile face of the valve seat being the lower extremity of the stem adapted to cooperate with a fixed face surrounding a return conduit provided in a nozzle body and opening axially in the valve bore.
- the invention also extends to an arrangement of a control valve as described above and a nozzle assembly.
- the upper face of the nozzle body is in surface sealing abutment against the lower face of the control valve and, the opening of the return conduit in the upper face of said nozzle body is axially centred in the opening of the valve bore in the lower face of the valve body.
- the fixed face of the seat is the face surrounding the opening of the return conduit in said upper face of the nozzle body.
- the invention further extends to a fuel injector comprising a control valve as mentioned above.
- a fuel injector 10 extending along a longitudinal axis A1 and which comprises from top to bottom, according to the non-limiting orientation of the figure, a head 12, an actuation member 14, a control valve 16 and a nozzle assembly 18.
- figure 1 will serve the description and for clarity and simplification purposes terms such as "right, left, high, low, over, under, upper, lower, above or below” may be utilized without intention to limit the scope of the application.
- the head 12 in integral to the top of the actuation member 14 and is provided with an inlet 20, adapted to be connected to a high pressure fuel source such as a common rail reservoir, and also with an outlet 22, barely visible on the figure, adapted to be connected a low pressure return line leading to a low pressure reservoir.
- a high pressure fuel source such as a common rail reservoir
- the actuation member 14 comprises an elongated body 24, also identified as a "nozzle holder body, or NHB", mainly cylindrical, extending from the head 12 to a lower transversal face 26. Externally, in the vicinity of said lower face 26, the body 24 is provided with a male thread 28 for complementary engagement of the female thread 30 of a capnut 32.
- NHB nozzle holder body
- the body 24 is provided with a bore 34 extending along a second axis A2, parallel and distinct from the longitudinal axis A1, said bore 34 opening in the lower face 26 and, in said bore 34 is fixedly arranged an electrical coil 36 whose underside is flush with the lower face 26 of the body 24. From the top of the coil 36 extend, through a specific channel, electrical connecting members 37, such as rigid cables, which connect to a connector 38 enabling electrical link of the coil 36 to a non-represented control unit.
- the coil 36 itself is further provided with a central bore 39 opening on said underside and in which is arranged a valve spring 40 slightly protruding out of said bore 39.
- the body 24 is further provided with fuel conduit that will be detailed later.
- the control valve 16 comprises a cylindrical body 42 which extends from an upper face 44, arranged in sealing abutment against the lower face 26 of the actuator body, to a lower face 46.
- the valve body 42 is provided with a wide and shallow recess 48 opening in said upper face 44 and from the bottom of which extends along the second axis A2 and toward the lower face 46 a hydraulic distributor bore 50.
- the injector represented on figure 1 which serves this description is just a non-limiting example of injector and numerous alternative embodiments exist and will be mentioned but, those alternatives which would be unintentionally omitted would not be excluded for the scope of protection provided by the claims.
- the longitudinal axis A1 and the second axis A2 have been described as distinct and parallel. This offset, introduced originally in patent EP1693563 , presents numerous advantages but injectors having both axes coincident exist and can also benefit from the teachings of the present invention.
- said distributor bore 50 is a through bore opening in the lower face 46 of the valve body.
- the bore 50 opens with a narrow upper neck 52 that continues into a larger lower section 54.
- a cylindrical sleeve 56 provided with a plurality of radial through holes 58.
- the sleeve 56 and the bore 54 have a single area of interference 60 which is in the vicinity of the lower face 46 of the valve body.
- the sleeve 56 is upwardly inserted in the bore 54 from said lower face 46 and, at first, the insertion is easy and requires no force at all, it is only when approaching the full insertion that the sleeve 56, provided with a slightly larger section, comes in interference with the bore 54 and a higher force is required to complete the insertion operation.
- the control valve 16 further comprises a moving member slidably arranged in the sleeve 56.
- Said member is an armature-stem assembly 62 comprising a magnetic armature 64 that has a thick disc-shape in the centre of which is enshrined and crimped the upper extremity of a cylindrical stem shaft 66 extending perpendicularly to the armature 64 toward a lower extremity 68.
- the stem 66 is inserted in the sleeve 56 so the armature 64 is arranged in the recess 48.
- the recess 48 and the narrow upper neck 52 connect in a female conical face, or alternatively toroidal, said face constituting the fixed face 70 of a valve seat 72, said fixed face 70 cooperating with a complementary male conical face 74 integral to the stem 66 forming the mobile face 74 of the valve seat 72.
- the armature-stem assembly 62 can translate between an upper position, or open position OPV of the valve seat 72 where the mobile face 74 is at a distance from the fixed face 70 and, a lower position, or closed position CPV of the valve seat 72 where both faces 70, 74, are in sealing contact.
- the armature-stem assembly 62 is permanently solicited toward the closed position CPV by the valve spring 40 that protrudes out of the central bore 39 of the coil and abuts against the head of the stem that is flush in surface, or slightly exceed in the centre of the armature 64.
- the fuel injector 10 of figure 1 further comprises, below the control valve 16, the nozzle assembly 18 which comprises a nozzle body 76 downwardly extending along the longitudinal axis A1 from an upper face 78, that is in sealing abutment against the lower face 46 of the valve body, into an upper large section 80, then into a lower thinner section 82 having a pointy lower extremity forming an injection nozzle 84 provided with a plurality of spray holes 86.
- the upper and lower sections 80, 82 connect through an annular shoulder 88 and, as shown on figure 1 , the lower section 82 is inserted in the capnut 32 which comes in abutment against said shoulder 88 then upwardly extends over the control valve 16 and complementary threads 28, 30, on the actuation member 24.
- the stack is sealed thanks to the mirror quality of the surfaces in contact and also to the important torque applied to the capnut 32.
- the nozzle body 76 is provided with an axial A1 main bore 90 in which is slidably arranged a needle valve 92 guided between an upper guide 94, in the vicinity of the upper face 78 of the nozzle body, and a lower guide 96 in the vicinity of the spray holes 86.
- the needle 92 axially extends from a head 98 arranged in the upper guide 94 to a pointy lower extremity 100 that cooperates with the inner face of the nozzle body to form an injection valve 102 enabling, or forbidding, fuel spray through the spray holes 86.
- the space in the upper guide 94 forms a control chamber 104 in which is compressed a needle spring 106 between the head 98 of the needle and the lower face 46 of the valve body that forms the ceiling of the control chamber 104.
- the needle valve 92 is able to axially translate between an upper, or open position OPN, and a lower, or closed position of the needle CPN.
- OPN open position
- CPN closed position
- the upper guide 94 is integral to the nozzle body 76.
- the fuel injector 10 is further provided with a high pressure fuel circuit 108 and also with a return circuit 110.
- the high pressure circuit 108 comprises a plurality of conduits complementary arranged to enable high pressure fuel to flow from the inlet 20 to the spray holes 86 and also into the control chamber 104.
- the return circuit 110 also comprises a plurality of conduits complementary arranged to enable fuel to return from the control chamber 104 to the outlet 22.
- the return circuit 110 comprises an evacuation conduit 112 extending from the control chamber 104 and opening in the lateral face of the distributor bore 50, then it continues through the radial through holes 58 of the sleeve 56, then upwardly in the upper neck 52 of the distributor bore where it opens in the recess 48 forming a low pressure chamber. Further conduits enable the fuel to flow from said chamber toward the outlet.
- the coil 36 In a first step the coil 36 is not electrically energized, it does not generate a magnetic field and so it does not attract the armature 64. Therefore the armature-stem assembly 62 is pushed by the valve spring 40 in the closed position CPV of the valve.
- the high pressure fuel that permanently enters via the inlet 20 pressurizes the control chamber 104 which solicits the valve needle 92 toward the closed position CPN where fuel spray is prevented.
- the coil 36 is electrically energized and it generates a magnetic field that attracts the armature 64.
- the armature-stem assembly 62 upwardly moves into the open position OPV of the valve.
- the high pressure fuel contained into the control chamber 104 can now exit via the evacuation conduit 112, the through holes 58, between the fixed 70 and mobile faces 74 of the valve seat 72 and enter the low pressure chamber 48.
- This evacuation creates a pressure drop in the control chamber 104 and, the pressure differential thus created between the two ends of the needle 92 displaces said needle 92 toward the open position OPN enabling fuel spray.
- the high pressure fuel evacuated from the control chamber 104 gets around the sleeve 56 which shrinks and slightly elongates.
- the elongation occurs in the upper extremity of the sleeve 56 that is free.
- said slight shrinking and elongation do not affect in anyway the quality to the operation of the valve seat 72.
- the distributor bore 50 is a blind bore and does not open in the lower face 46 of the valve body. Instead, at the lower end of the bore 50 centrally opens a return conduit 114 of smaller diameter than said bore 50, said return conduit 114 making a right angle turn to radially extend through the valve body 42, Alternatives exists with other angles than a right angle.
- the face surrounding the opening of the return conduit 114 forms the fixed face 70 of the valve seat 72 and, the lower extremity 68 of the stem is complementary shaped forming the mobile face 74 of the valve seat 72.
- the sleeve 56 is downwardly inserted from the recess 48 and the single area of interference 60 with the bore 50 is in the upper side, in the vicinity of said recess 48.
- the stem 66 extends through the sleeve 56 and protrudes at the lower extremity of the sleeve 56 so that the faces 70, 74, of the valve seat close in sealing contact when the armature-stem assembly 62 is in closed position CPV
- evacuation conduit 112 still laterally opens in the distributor bore 50 but, when the valve seat in open the fuel evacuates directly into the return conduit 114and, the sleeve 56 of this second embodiment is not provided with radial through holes.
- a third embodiment of the control valve 16 is now described in reference to figures 4 and 5 , and also by way of differences with the previous embodiments.
- the distributor bore 50 is a through bore opening in the recess 48 and also in the lower face 46 of the valve body.
- the bore comprises an upper section of a smaller diameter and a little shorter than a lower section that is of a slightly larger diameter and slightly longer.
- the sleeve 56 extends through both sections, the sleeve 56 being press fitted in interference in the upper section and being free in the lower section.
- the stem 66 comprises two distinct members, an upper stem 116 enshrined and crimped in the armature and, a lower stem 118 having at its lower extremity 68 the transversal mobile face 74 of the valve seat 72.
- said mobile face is provided with a small central protrusion downwardly extending and engaging without any contacts in the opening of the return conduit 114.
- the sleeve 56 is upwardly inserted in the bore 50 from the lower face 46 of the valve body. At first the insertion does not require efforts and when the sleeve 56 engages into the upper section then the insertion effort grows.
- the armature-upper stem assembly is downwardly inserted from the central opening of the sleeve from the recess and, the lower stem 118 is upwardly inserted in the sleeve 56 from the opening of the bore 50 in the lower face 46 of the valve body.
- the upper 116 and lower 118 stems are in contact with each other but are not fixed to each other.
- the return conduit 114 is entirely arranged in the nozzle body 76. It radially extends just below the upper face 78 until it reaches the second axis A2 where an axial smaller section upwardly opens in the upper face 78, exactly in the center of the opening of the bore 50 into the lower face 46 of the valve body.
- the return conduit would be provided in said upper guide element.
- the evacuation conduit 112 upwardly opens in the bottom of the distribution bore 50.
- the upward opening of the discharge conduit 112 in the hydraulic distribution bore 50 is not closed by the lower end of the stem 68.
- the section plane of the figures represents said opening beneath end stem, said opening is permanently open.
- the coil 36 is not energized and the armature-stem assembly 62 is downwardly pushed by the valve spring 40 toward a closed position CPV of the valve.
- the upper stem 116 pushes the lower stem 118 which lower extremity 68 seals the return conduit 114.
- the high pressure built in the control chamber 104 forces the needle valve 92 into the closed position CPN forbidding injection events..
- the coil 36 is energized and it upwardly attracts the magnetic armature and the upper stem 116 and, the lower stem 118 follows the upward displacement toward the open position OPV as it is being sucked by the upper stem 116 and, the fuel captive in the control chamber 104 can evacuate and flow into the return conduit 114.
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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
A control valve (16) of a fuel injector is provided with a cylindrical valve body (42) extending along a main axis from an upper face (44) to a lower face (46), said body (42) being provided with a large cylindrical shallow recess (48) opening in said upper face (44) and in the bottom of which opens a valve distributor bore (50) axially extending toward the lower face (46). The control valve further has a magnetic armature-stem assembly (62) and, guiding means (56) for slidably guiding the armature-stem assembly (62) into the valve bore (50) and with seating means (70, 72, 74), distinct and independent means from the guiding means (56), for opening or closing a fluid communication between a high pressure conduit (112) and a return conduit (110), both conduits opening in said bore (50).
Description
- The present invention relates to a fuel injector and more particularly to a control valve.
- Fuel injectors known in the art are provided with control valve controlling the fuel pressure in a control chamber that cooperates with a valve needle in order to enable or forbid fuel spray.
- The control valve comprises a cylindrical body extending axially from an upper face to a lower face and provided with a shallow recess opening in the upper face and from the center of the bottom of which extends toward the lower face a valve bore in which open a high pressure conduit in fluid communication with said control chamber and, a return conduit in fluid communication with a low pressure reservoir. A cylindrical sleeve is fixedly arranged in the bore by means of two press fitted annular areas, one being at the upper extremity of the bore, the other being at the lower extremity of the bore. Inside the sleeve is slidably arranged the stem of an armature-stem assembly that cooperates with a coil generating a magnetic field. The high pressure conduit laterally opens in the bore, between the press fit annular areas and, the return conduit comprises the shallow recess that creates a low pressure chamber.
- The armature-stem assembly slides between an upper position where it opens a valve seat creating a fluid communication between the high pressure conduit and the return conduit and, a lower position wherein said valve seat is closed. The valve seat comprises a fixed face that is an upper face of the sleeve and a mobile face that is a conical face of the stem arranged just under the armature.
- It has been observed that, in use, under the influence of the high pressure fuel surrounding the sleeve, said sleeve shrinks in diameter and consequently to stretch out in length. These variations are of micrometers, or even sub-micrometers, but still the elongations generate micro displacement that are not prevented by the press fit areas and that are detrimental to the correct operation of the control valve, especially in that the valve seat slowly displaces.
- Accordingly, it is an object of the present invention to solve the above mentioned problems in providing a control valve of a fuel injector, said valve being provided with a cylindrical valve body extending along a main axis from an upper face to a lower face. The body is provided with a large cylindrical shallow recess opening in said upper face and in the bottom of which opens a valve distributor bore axially extending toward the lower face. The control valve is further provided with a magnetic armature-stem assembly, the magnetic armature having a thick disc-shape in the centre of which is enshrined and crimped a cylindrical stem shaft extending perpendicularly from the armature to a lower extremity and, guiding means for slidably guiding the armature-stem assembly into the valve bore and with, seating means, for opening or closing a fluid communication between a high pressure conduit and a return conduit, both conduits opening in said bore.
- The seating means and the guiding means are distinct and independent means.
- More particularly, the guiding means is a cylindrical sleeve extending from an upper extremity to a lower extremity and fixedly press fitted in the valve bore, the stem being slidably engaged in said sleeve and, the seating means comprises a valve seat having a fixed face surrounding the opening of the return conduit cooperating with a mobile face integral to the stem.
- Also, the sleeve is fixed in the bore by means of a single annular area of interference with the bore. Particularly, the single annular area of interference is a proximal an extremity of the sleeve and the fixed face of the valve seat is proximal the opposite extremity of the sleeve.
- The valve bore opens in the lower face of the body, said single annular area of interference being proximal to said lower face and, the valve seat is in the opening of bore in the bottom of the recess, the fixed face being the interconnecting face surrounding the opening of the valve bore in the recess, the mobile face being a conical face of the stem proximal the armature.
- In a particular embodiment, the high pressure conduit laterally opens in the valve bore and the shallow recess is part to the return conduit, the sleeve being provided with radial through holes enabling, in use the high pressure fuel to flow from the high pressure conduit, through the sleeve and into the return conduit.
- In specific embodiments, the valve bore is a through bore opening in the recess and in the lower face of the body, the single annular area of interference being proximal to the recess an, the valve seat is in the opening of bore in the lower face of the valve body, the mobile face of the valve seat being the lower extremity of the stem adapted to cooperate with a fixed face surrounding a return conduit provided in a nozzle body and opening axially in the valve bore.
- The invention also extends to an arrangement of a control valve as described above and a nozzle assembly. The upper face of the nozzle body is in surface sealing abutment against the lower face of the control valve and, the opening of the return conduit in the upper face of said nozzle body is axially centred in the opening of the valve bore in the lower face of the valve body. The fixed face of the seat is the face surrounding the opening of the return conduit in said upper face of the nozzle body.
- The invention further extends to a fuel injector comprising a control valve as mentioned above.
- The present invention is now described by way of example with reference to the accompanying drawings in which:
-
Figure 1 is a longitudinal section of a fuel injector provided with a control valve as per the invention. -
Figure 2 is a section of a control valve as per a first embodiment of the invention. -
Figure 3 is a section of a control valve as per a second embodiment not part to the invention. -
Figure 4 is a section of a control valve as per a third embodiment of the invention. -
Figure 5 is a magnified view of the control valve offigure 4 . - As per
figure 1 is represented afuel injector 10 extending along a longitudinal axis A1 and which comprises from top to bottom, according to the non-limiting orientation of the figure, ahead 12, anactuation member 14, acontrol valve 16 and anozzle assembly 18. - As mentioned, the orientation of
figure 1 will serve the description and for clarity and simplification purposes terms such as "right, left, high, low, over, under, upper, lower, above or below" may be utilized without intention to limit the scope of the application. - The
head 12 in integral to the top of theactuation member 14 and is provided with aninlet 20, adapted to be connected to a high pressure fuel source such as a common rail reservoir, and also with anoutlet 22, barely visible on the figure, adapted to be connected a low pressure return line leading to a low pressure reservoir. - The
actuation member 14 comprises anelongated body 24, also identified as a "nozzle holder body, or NHB", mainly cylindrical, extending from thehead 12 to a lowertransversal face 26. Externally, in the vicinity of saidlower face 26, thebody 24 is provided with a male thread 28 for complementary engagement of the female thread 30 of acapnut 32. - Internally, the
body 24 is provided with abore 34 extending along a second axis A2, parallel and distinct from the longitudinal axis A1, said bore 34 opening in thelower face 26 and, in saidbore 34 is fixedly arranged anelectrical coil 36 whose underside is flush with thelower face 26 of thebody 24. From the top of thecoil 36 extend, through a specific channel, electrical connectingmembers 37, such as rigid cables, which connect to aconnector 38 enabling electrical link of thecoil 36 to a non-represented control unit. Thecoil 36 itself is further provided with acentral bore 39 opening on said underside and in which is arranged avalve spring 40 slightly protruding out of saidbore 39. - The
body 24 is further provided with fuel conduit that will be detailed later. - The
control valve 16 comprises acylindrical body 42 which extends from anupper face 44, arranged in sealing abutment against thelower face 26 of the actuator body, to alower face 46. Internally, thevalve body 42 is provided with a wide andshallow recess 48 opening in saidupper face 44 and from the bottom of which extends along the second axis A2 and toward the lower face 46 a hydraulic distributor bore 50. - The injector represented on
figure 1 which serves this description is just a non-limiting example of injector and numerous alternative embodiments exist and will be mentioned but, those alternatives which would be unintentionally omitted would not be excluded for the scope of protection provided by the claims. As an example, the longitudinal axis A1 and the second axis A2 have been described as distinct and parallel. This offset, introduced originally in patentEP1693563 , presents numerous advantages but injectors having both axes coincident exist and can also benefit from the teachings of the present invention. - In a first embodiment of the
control valve 16, represented infigure 2 , said distributor bore 50 is a through bore opening in thelower face 46 of the valve body. In the wide andshallow recess 48, thebore 50 opens with a narrowupper neck 52 that continues into a largerlower section 54. In said largerlower section 54 is fixedly press fitted acylindrical sleeve 56 provided with a plurality of radial throughholes 58. Thesleeve 56 and thebore 54 have a single area ofinterference 60 which is in the vicinity of thelower face 46 of the valve body. Indeed, during the manufacturing process, thesleeve 56 is upwardly inserted in thebore 54 from saidlower face 46 and, at first, the insertion is easy and requires no force at all, it is only when approaching the full insertion that thesleeve 56, provided with a slightly larger section, comes in interference with thebore 54 and a higher force is required to complete the insertion operation. - The
control valve 16 further comprises a moving member slidably arranged in thesleeve 56. Said member is an armature-stem assembly 62 comprising amagnetic armature 64 that has a thick disc-shape in the centre of which is enshrined and crimped the upper extremity of acylindrical stem shaft 66 extending perpendicularly to thearmature 64 toward alower extremity 68. As visible on the figures, thestem 66 is inserted in thesleeve 56 so thearmature 64 is arranged in therecess 48. - In the bottom of the
recess 48, therecess 48 and the narrowupper neck 52 connect in a female conical face, or alternatively toroidal, said face constituting the fixedface 70 of avalve seat 72, said fixedface 70 cooperating with a complementary maleconical face 74 integral to thestem 66 forming themobile face 74 of thevalve seat 72. - As said, once in place in the
valve body 42 the armature-stem assembly 62 can translate between an upper position, or open position OPV of thevalve seat 72 where themobile face 74 is at a distance from the fixedface 70 and, a lower position, or closed position CPV of thevalve seat 72 where both faces 70, 74, are in sealing contact. The armature-stem assembly 62 is permanently solicited toward the closed position CPV by thevalve spring 40 that protrudes out of thecentral bore 39 of the coil and abuts against the head of the stem that is flush in surface, or slightly exceed in the centre of thearmature 64. - The
fuel injector 10 offigure 1 further comprises, below thecontrol valve 16, thenozzle assembly 18 which comprises anozzle body 76 downwardly extending along the longitudinal axis A1 from anupper face 78, that is in sealing abutment against thelower face 46 of the valve body, into an upperlarge section 80, then into a lowerthinner section 82 having a pointy lower extremity forming aninjection nozzle 84 provided with a plurality ofspray holes 86. The upper andlower sections annular shoulder 88 and, as shown onfigure 1 , thelower section 82 is inserted in thecapnut 32 which comes in abutment against saidshoulder 88 then upwardly extends over thecontrol valve 16 and complementary threads 28, 30, on theactuation member 24. - The stack is sealed thanks to the mirror quality of the surfaces in contact and also to the important torque applied to the
capnut 32. - The
nozzle body 76 is provided with an axial A1main bore 90 in which is slidably arranged aneedle valve 92 guided between an upper guide 94, in the vicinity of theupper face 78 of the nozzle body, and alower guide 96 in the vicinity of thespray holes 86. Theneedle 92 axially extends from ahead 98 arranged in the upper guide 94 to a pointylower extremity 100 that cooperates with the inner face of the nozzle body to form aninjection valve 102 enabling, or forbidding, fuel spray through thespray holes 86. - Above the
head 98 of the needle, the space in the upper guide 94 forms acontrol chamber 104 in which is compressed aneedle spring 106 between thehead 98 of the needle and thelower face 46 of the valve body that forms the ceiling of thecontrol chamber 104. In place, theneedle valve 92 is able to axially translate between an upper, or open position OPN, and a lower, or closed position of the needle CPN. In open position OPN theinjection valve 102 is open enabling fuel spray and, in closed position CPN theinjection valve 102 is closed preventing fuel spray. - In the fuel injector of
figure 1 , the upper guide 94 is integral to thenozzle body 76. Alternative embodiments exist where the upper guide is an independent component sandwiched between the nozzle body and the control valve. The present invention can benefit all alternatives, whatever the embodiment. - The
fuel injector 10 is further provided with a highpressure fuel circuit 108 and also with areturn circuit 110. Thehigh pressure circuit 108 comprises a plurality of conduits complementary arranged to enable high pressure fuel to flow from theinlet 20 to the spray holes 86 and also into thecontrol chamber 104. - The
return circuit 110 also comprises a plurality of conduits complementary arranged to enable fuel to return from thecontrol chamber 104 to theoutlet 22. In this first embodiment, thereturn circuit 110 comprises anevacuation conduit 112 extending from thecontrol chamber 104 and opening in the lateral face of the distributor bore 50, then it continues through the radial throughholes 58 of thesleeve 56, then upwardly in theupper neck 52 of the distributor bore where it opens in therecess 48 forming a low pressure chamber. Further conduits enable the fuel to flow from said chamber toward the outlet. - The operation of the
fuel injector 10 is now briefly described. - In a first step the
coil 36 is not electrically energized, it does not generate a magnetic field and so it does not attract thearmature 64. Therefore the armature-stem assembly 62 is pushed by thevalve spring 40 in the closed position CPV of the valve. The high pressure fuel that permanently enters via theinlet 20 pressurizes thecontrol chamber 104 which solicits thevalve needle 92 toward the closed position CPN where fuel spray is prevented. - In a second step the
coil 36 is electrically energized and it generates a magnetic field that attracts thearmature 64. The armature-stem assembly 62 upwardly moves into the open position OPV of the valve. The high pressure fuel contained into thecontrol chamber 104 can now exit via theevacuation conduit 112, the throughholes 58, between the fixed 70 and mobile faces 74 of thevalve seat 72 and enter thelow pressure chamber 48. This evacuation creates a pressure drop in thecontrol chamber 104 and, the pressure differential thus created between the two ends of theneedle 92 displaces saidneedle 92 toward the open position OPN enabling fuel spray. - During this second step, the high pressure fuel evacuated from the
control chamber 104 gets around thesleeve 56 which shrinks and slightly elongates. As the lower extremity of thesleeve 56 is fixed in thebore 54, the elongation occurs in the upper extremity of thesleeve 56 that is free. Also, as thevalve seat 72 is independent from thesleeve 56, said slight shrinking and elongation do not affect in anyway the quality to the operation of thevalve seat 72. - A second embodiment of the
control valve 16, not part to the invention, is now described in reference tofigure 3 , and by way of differences with the first embodiment. - Although the general principle of having a sleeve fixed in the hydraulic bore thank to a single area of press fit and, said sleeve not being part of the valve seat, the major difference of this second embodiment is that the sleeve is fixed by press fit in its upper area, close to the
recess 48 and thevalve seat 72 is at the bottom of the distributor bore 50. - As visible on
figure 3 , the distributor bore 50 is a blind bore and does not open in thelower face 46 of the valve body. Instead, at the lower end of thebore 50 centrally opens areturn conduit 114 of smaller diameter than said bore 50, saidreturn conduit 114 making a right angle turn to radially extend through thevalve body 42, Alternatives exists with other angles than a right angle. The face surrounding the opening of thereturn conduit 114 forms the fixedface 70 of thevalve seat 72 and, thelower extremity 68 of the stem is complementary shaped forming themobile face 74 of thevalve seat 72. - As visible on the figure, the
sleeve 56 is downwardly inserted from therecess 48 and the single area ofinterference 60 with thebore 50 is in the upper side, in the vicinity of saidrecess 48. In place, thestem 66 extends through thesleeve 56 and protrudes at the lower extremity of thesleeve 56 so that thefaces stem assembly 62 is in closed position CPV - Furthermore, the
evacuation conduit 112 still laterally opens in the distributor bore 50 but, when the valve seat in open the fuel evacuates directly into the return conduit 114and, thesleeve 56 of this second embodiment is not provided with radial through holes. - A third embodiment of the
control valve 16 is now described in reference tofigures 4 and 5 , and also by way of differences with the previous embodiments. - The general principles remain but, for this third embodiment the distributor bore 50 is a through bore opening in the
recess 48 and also in thelower face 46 of the valve body. The bore comprises an upper section of a smaller diameter and a little shorter than a lower section that is of a slightly larger diameter and slightly longer. - The
sleeve 56 extends through both sections, thesleeve 56 being press fitted in interference in the upper section and being free in the lower section. - The
stem 66 comprises two distinct members, anupper stem 116 enshrined and crimped in the armature and, alower stem 118 having at itslower extremity 68 the transversalmobile face 74 of thevalve seat 72. Optionally, as shown on the figure, said mobile face is provided with a small central protrusion downwardly extending and engaging without any contacts in the opening of thereturn conduit 114. - In this third embodiment the
sleeve 56 is upwardly inserted in thebore 50 from thelower face 46 of the valve body. At first the insertion does not require efforts and when thesleeve 56 engages into the upper section then the insertion effort grows. - Once the
sleeve 56 is in place, the armature-upper stem assembly is downwardly inserted from the central opening of the sleeve from the recess and, thelower stem 118 is upwardly inserted in thesleeve 56 from the opening of thebore 50 in thelower face 46 of the valve body. The upper 116 and lower 118 stems are in contact with each other but are not fixed to each other. - As visible on
figure 4 , and even magnified infigure 5 , thereturn conduit 114 is entirely arranged in thenozzle body 76. It radially extends just below theupper face 78 until it reaches the second axis A2 where an axial smaller section upwardly opens in theupper face 78, exactly in the center of the opening of thebore 50 into thelower face 46 of the valve body. Alternatively, in a fuel injector having a non-integral upper guide the return conduit would be provided in said upper guide element. - Also, the
evacuation conduit 112 upwardly opens in the bottom of the distribution bore 50. The upward opening of thedischarge conduit 112 in the hydraulic distribution bore 50 is not closed by the lower end of thestem 68. Although the section plane of the figures represents said opening beneath end stem, said opening is permanently open. - The operation of this third embodiment is now briefly described.
- At first, the
coil 36 is not energized and the armature-stem assembly 62 is downwardly pushed by thevalve spring 40 toward a closed position CPV of the valve. Theupper stem 116 pushes thelower stem 118 whichlower extremity 68 seals thereturn conduit 114. The high pressure built in thecontrol chamber 104 forces theneedle valve 92 into the closed position CPN forbidding injection events.. - In a second step the
coil 36 is energized and it upwardly attracts the magnetic armature and theupper stem 116 and, thelower stem 118 follows the upward displacement toward the open position OPV as it is being sucked by theupper stem 116 and, the fuel captive in thecontrol chamber 104 can evacuate and flow into thereturn conduit 114. - The following references are utilized in this description.
- 10
- injector
- 12
- head of the injector
- 14
- actuation member
- 16
- control valve
- 18
- nozzle assembly
- 20
- inlet
- 22
- outlet
- 24
- actuator body
- 26
- lower face of the actuator body
- 28
- male thread of the actuator body
- 30
- female thread of the capnut
- 32
- capnut
- 34
- bore
- 36
- coil
- 37
- electrical connecting members
- 38
- connector
- 39
- central bore
- 40
- valve spring
- 42
- valve body
- 44
- upper face of the valve body
- 46
- lower face of the valve body
- 48
- recess - low pressure chamber
- 50
- hydraulic distributor bore
- 52
- narrow upper neck of the distributor bore
- 54
- larger lower section of the distributor bore
- 56
- sleeve
- 58
- radial through holes
- 60
- single area of interference
- 62
- armature-stem assembly
- 64
- magnetic armature
- 66
- stem
- 68
- lower extremity of the stem
- 70
- fixed face of the valve seat
- 72
- valve seat
- 74
- mobile face of the valve seat
- 76
- nozzle body
- 78
- upper face of the nozzle body
- 80
- upper large section of the nozzle body
- 82
- lower narrower section of the nozzle body
- 84
- injection nozzle
- 86
- spray holes
- 88
- shoulder face
- 90
- main bore in the nozzle body
- 92
- needle valve
- 94
- upper guide
- 96
- lower guide
- 98
- head of the needle
- 100
- pointy extremity of the needle
- 102
- injection valve
- 104
- control chamber
- 106
- needle spring
- 108
- high pressure fuel circuit
- 110
- return circuit
- 112
- evacuation conduit
- 114
- return conduit - 2nd embodiment
- 116
- upper stem - 3rd embodiment
- 118
- lower stem - 3rd embodiment
- 120
- second mobile face - 3rd embodiment
- A1
- longitudinal axis
- A2
- second axis
- OPV
- open position of the valve
- CPV
- closed position of the valve
- OPN
- open position of the needle
- CPN
- closed position of the needle
Claims (5)
- Control valve (16) of a fuel injector (10), said valve (16) being provided with- a cylindrical valve body (42) extending along a main axis (A1) from an upper face (44) to a lower face (46), said body (42) being provided with a large cylindrical shallow recess (48) opening in said upper face (44) and in the bottom of which opens a valve distributor bore (50) axially extending toward the lower face (46) and with,- a magnetic armature-stem assembly (62) provided with a magnetic armature (64) having a thick disc-shape in the centre of which is enshrined and crimped a cylindrical stem shaft (66) extending perpendicularly from the armature (64) to a lower extremity (68) and,- guiding means (56) for slidably guiding the armature-stem assembly (62) into the valve bore (50) and with,- seating means (70, 72, 74) for opening or closing a fluid communication between a high pressure conduit (112) and a return conduit (110), both conduits opening in said bore (50),characterized in that
the seating means (70, 72, 74) and the guiding means (56) are distinct and independent means and wherein- the guiding means (56) is a cylindrical sleeve (56) extending from an upper extremity to a lower extremity and fixedly press fitted in said valve bore (50), the stem (66) being slidably engaged in said sleeve (56),- the seating means (70, 72, 74) is a valve seat (72) comprising a fixed face (70) surrounding the opening of the return conduit (110) cooperating with a mobile face (74) integral to the stem (66) and wherein- the sleeve (56) is fixed in the bore (50) by means of a single annular area of interference (60) with the bore (50) and wherein- the single annular area of interference (60) is a proximal an extremity of the sleeve (56) and,- the fixed face (70) of the valve seat (72) is proximal the opposite extremity of the sleeve (72) and wherein- the valve bore (50) is a through bore opening in the recess (48) and in the lower face (46) of the body, the single annular area of interference (60) being proximal to the recess (48) and wherein,- the valve seat (72) is in the opening of bore (50) in the lower face (46) of the valve body, the mobile face (74) of the valve seat (72) being the lower extremity (68) of the stem adapted to cooperate with a fixed face (70) surrounding a return conduit (114) provided in a nozzle body and opening axially in the valve bore (50). - Control valve (16) as claimed in claim 1 wherein- the valve bore (50) opens in the lower face (46) of the body, said single annular area of interference (60) being proximal to said lower face (46) and wherein,- the valve seat (72) is in the opening of bore (50) in the bottom of the recess (48), the fixed face (70) being the interconnecting face surrounding the opening of the valve bore (50) in the recess (48), the mobile face (74) being a conical face of the stem (66) proximal the armature (64).
- Control valve (16) as claimed in claim 2 wherein the high pressure conduit (112) laterally opens in the valve bore (50) and, the shallow recess (48) is part to the return conduit (110), the sleeve (56) being provided with radial through holes (58) enabling, in use the high pressure fuel to flow from the high pressure conduit (112), through the sleeve (56) and into the return conduit (110).
- Arrangement of a control valve (16) as claimed in any one of the preceding claims and a nozzle assembly (18), the upper face (78) of the nozzle body (76) being in surface sealing abutment against the lower face (46) of the control valve and, the opening of the return conduit (114) in the upper face (78) of said nozzle body (76) is axially centred in the opening of the valve bore (50) in the lower face (46) of the valve body, the fixed face (70) of the seat (72) being the face surrounding the opening of the return conduit (114) in said upper face (78) of the nozzle body.
- Fuel injector (10) comprising a control valve (16) as claimed in any one of the claims 1 to 4.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GBGB1418256.2A GB201418256D0 (en) | 2014-10-15 | 2014-10-15 | Control valve of a fuel injector |
PCT/EP2015/072436 WO2016058825A1 (en) | 2014-10-15 | 2015-09-29 | Control valve of a fuel injector |
EP15771935.2A EP3207242A1 (en) | 2014-10-15 | 2015-09-29 | Control valve of a fuel injector |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP15771935.2A Division EP3207242A1 (en) | 2014-10-15 | 2015-09-29 | Control valve of a fuel injector |
Publications (1)
Publication Number | Publication Date |
---|---|
EP3376016A1 true EP3376016A1 (en) | 2018-09-19 |
Family
ID=52001468
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP18165540.8A Withdrawn EP3376016A1 (en) | 2014-10-15 | 2015-09-29 | Control valve of a fuel injector |
EP15771935.2A Withdrawn EP3207242A1 (en) | 2014-10-15 | 2015-09-29 | Control valve of a fuel injector |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP15771935.2A Withdrawn EP3207242A1 (en) | 2014-10-15 | 2015-09-29 | Control valve of a fuel injector |
Country Status (4)
Country | Link |
---|---|
EP (2) | EP3376016A1 (en) |
JP (1) | JP2017531128A (en) |
GB (1) | GB201418256D0 (en) |
WO (1) | WO2016058825A1 (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2554359B (en) * | 2016-09-21 | 2020-03-18 | Delphi Tech Ip Ltd | Dual fuel injector |
GB2559174B (en) | 2017-01-30 | 2020-04-08 | Delphi Tech Ip Ltd | Control valve assembly and method of manufacturing thereof |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2350662A (en) * | 1999-06-03 | 2000-12-06 | Lucas Ind Plc | Valve for a fuel injector |
WO2013110710A1 (en) * | 2012-01-26 | 2013-08-01 | Delphi Technologies Holding S.À.R.L. | A control valve |
WO2014048605A1 (en) * | 2012-09-25 | 2014-04-03 | Delphi International Operations Luxembourg S.À.R.L. | Fuel injector |
-
2014
- 2014-10-15 GB GBGB1418256.2A patent/GB201418256D0/en not_active Ceased
-
2015
- 2015-09-29 WO PCT/EP2015/072436 patent/WO2016058825A1/en active Application Filing
- 2015-09-29 EP EP18165540.8A patent/EP3376016A1/en not_active Withdrawn
- 2015-09-29 JP JP2017518522A patent/JP2017531128A/en active Pending
- 2015-09-29 EP EP15771935.2A patent/EP3207242A1/en not_active Withdrawn
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2350662A (en) * | 1999-06-03 | 2000-12-06 | Lucas Ind Plc | Valve for a fuel injector |
WO2013110710A1 (en) * | 2012-01-26 | 2013-08-01 | Delphi Technologies Holding S.À.R.L. | A control valve |
WO2014048605A1 (en) * | 2012-09-25 | 2014-04-03 | Delphi International Operations Luxembourg S.À.R.L. | Fuel injector |
Also Published As
Publication number | Publication date |
---|---|
EP3207242A1 (en) | 2017-08-23 |
WO2016058825A1 (en) | 2016-04-21 |
GB201418256D0 (en) | 2014-11-26 |
JP2017531128A (en) | 2017-10-19 |
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