FR2759738A1 - FUEL INJECTOR FOR INTERNAL COMBUSTION ENGINE - Google Patents

Abstract

Injector comprising a closure member (9) sliding axially in a bore (7) of the body (3). This member (9) has a sealing surface on the side of the combustion chamber to cooperate with a surface forming a valve seat (13) integral with the body of the injector. The member (9) has a pressure shoulder acting in the direction of the opening which arrives in a pressure chamber (17) whose section is widening. A pressure channel (19) connected to the high pressure fuel source opens into this pressure chamber. This chamber (17) is connected by an annular channel (23) to the seat surface (13). This channel is formed between the member (9) and the wall (7) of the bore. A second supply line (39) arrives in the pressure chamber (17) to supply the second fluid. This second pipe (39) passes completely into the body (3) and arrives directly in the pressure chamber (17).

Description

STATE OF THE ART The present invention relates to a injector for

  fuel for an internal combustion engine comprising an or-

  shutter guide guided in axial sliding in a bore of the valve body and whose end, on the side of the

  combustion bre, has a sealing surface

  pope which cooperates with a valve seat surface integral with the body of the injector to control the injection section, - a pressure shoulder cooperating in the direction of opening of the closure member, this shoulder being provided on the stem of the shutter member, entering a pressure chamber whose section widens, - a pressure channel capable of being connected to a high pressure fuel source opening further into this pressure chamber , - the pressure chamber formed between the rod of the member

  shutter and the wall of the hole being connected by a ca-

  axially extending annular nal to the valve seat surface, and

  - a second supply line in the injector body

  tor by which a second fluid is supplied to the section

injector injection.

  In such an injector for an internal combustion engine, known according to document DE-39 28 611-A1, a mixture or an emulsion of diesel fuel (diesel) is injected, to ensure optimum combustion with regard to the emission of pollutants. and water in the combustion chamber. For this, the injector comprises a shutter member in the form of a piston guided in axial sliding in the bore of an injector body; at its end located on the side of the combustion chamber, this member has a sealing surface by which it cooperates with the valve seat surface of the injector body to control the injection section or the

  release of the injection hole.

  The body of the obturation organ or for-

  mant valve has a pressure shoulder acting in the opening direction; through this organ it enters a

  enlarged section pressure chamber, into which

  also a pressure channel which can be connected to a

  fuel injection pump. The pressure channel is re-

  linked to the injection section by an annular channel, extending axially and formed between the closure member and the bore. To introduce the second fluid, in particular

  water, the known injector comprises a second supply line

  mentation which first crosses axially the body

  injector then opens into an annular volume formed

  1) be the injector body and a tightening nut. From there, the water arrives at the end of the annular channel, close to the valve seat, through an annular section formed between the injector body and the nut, to arrive at the end of the annular channel near the valve seat, between the closure member and the hole to pass to this place in the

  injector body through radial holes.

  However, the known injector has the disadvantage of a complicated construction because of the water supply channel between the nut and the body of the injector so that this 2) device is of an extremely complicated manufacture. . In addition, due to the small wall thickness which remains on the rod of the injector body, the known fuel injector is not suitable for high injection pressures reaching up to 1800 bars. Another drawback is the water supply in the area close to the valve seat which does not allow a good water / fuel emulsion to be produced. Advantages of the invention The object of the present invention is to remedy 3 () these drawbacks and to this end relates to an injector for

  fuel for internal combustion engine of the type defined above

  above, characterized in that the second supply line extends completely into the body of

  injector and opens directly into the pressure chamber.

  or at least close to the pressure chamber in a volume delimited between the shutter member and the wall of the bore. The injector according to the invention has the advantage that

  the supply of the second medium, in particular water, does not

  no more additional parts compared to known injectors, working at high injection pressures. Thus, the injector according to the invention can be used to inject fuel and water without requiring

  transformation of existing engines.

  This is advantageously made possible in that

  the second water supply line is complete-

  integrated into the injector support body and does not

  is found only at this location. The second conduct of ali-

  advantageously leads directly into the cham-

  bre of pressure from the injector or at least near the pressure chamber in the bore leading to the closure member. This preserves the initial wall thickness of the injector body, which allows the injector to continue to be used for fuel / water with pressures.

  fuel injection up to 1800 bars.

  As so the quantities of fuel and the pressures applied are higher than those applied to

  quantities of water supplied, the flow section of the con-

  fuel supply line is advantageously

  larger than the passage section of the pipe

  water supply. To ensure that the fuel mixture

  rant and water is preceded in the area near the headquarters of

  valve with pure fuel, there is provision, according to a

  laughing, a sleeve in the annular channel between the body of the injector and the closure member. This sleeve is provided with through holes through which the water mixes with the arrival of fuel; the size and arrangement of the holes is made so that the water supply reaches the bottom of the sleeve and the space below the sleeve

  remains filled with fuel, preferably diesel fuel.

  To facilitate its assembly, the sleeve can be split. To reach a fuel passage radially inside the sleeve and a water supply radially outside the sleeve, the latter is made at an angle at its end penetrating into the pressure chamber, in the direction

  of the water supply line.

  According to other alternative embodiments, the body

  of the shutter member has different forms of sec-

  tion at the level of the annular channel to promote mixing between the fuel and the water and form an emulsion, which

  Advantageously affects the quality of combustion.

  To achieve forced water guidance, you can give advance

  tagging in the section of the pressure chamber an oval shape; the pressurized fuel line and the line

  water supply leads each time in an oppo-

  placed at the end furthest from the section of the pressure channel to reach it. So that unmixed fuel is located upstream in the area close to the valve seat, it is advantageous to provide at this point a narrowed part of the body of the shutter member which forms

  an annular volume in the annular channel.

  Next to the mouth of the second supply line in the pressure chamber, it is possible as a variant to allow this second supply line to arrive in an area close to the pressure chamber.

  drilling of the obturation member. In this case it is

  so that the water supplied arrives via a connecting channel inside the obturation member, directly in a flat ground part of the obturation member, below the pressure chamber so that the fuel and the complementary fluid, in particular water, arrive separately in the

annular chamber.

  This constructive variant is particularly suitable

  especially for a stratification of the injected medium, according to which we first inject only fuel for

  pre-injection and in the second injection phase we in-

  jets only water then in the third phase or main phase we inject again practically only pure fuel. The connecting channel in the organ

  shutter, according to this variant, is

  advantageously formed by two holes which intersect in

bias in the obturation organ.

  The fuel injector according to the invention for injecting fuel and water can be produced as in the embodiments described, that is to say as an orifice nozzle with seat or alternatively as a lug nozzle5 or blind hole. In addition, the injector according to the invention can be used in all known injection installations

  such as pump and injector installations, common rail installations or pump, pipe and injector injection installations.

  Other advantages and interesting developments of the invention are described in the drawings and will appear

  in the description and the claims. Drawings Six examples of the construction of a

  fuel according to the invention for internal combustion engines

  dull are shown in the drawings and will be described below

  after. Thus: - Figure 1 is a simplified sectional view

  of an internal combustion engine cylinder head with an injec-

  fuel, FIG. 2 is a sectional view on an enlarged scale of the first exemplary embodiment according to FIG. 1, of the main parts of the body of the injector and of the closure member,

  - Figure 3 shows a second example of reali-

  sation presented analogously to that of FIG. 2, a sleeve being placed in the annular channel between the body of the injector and the closure member,

  - Figure 4 shows a third example of a

  reading similar to Figure 2, and whose organ

  obturation has grooves at the annular channel

laire,

  - Figure 5 shows a fourth example of a

  reading presented in a similar way to that of figure 2

  in which the shutter member has a dry profile

  four sides at the level of the annular channel, - Figure 6 shows a first section of the profile

  square of the shutter member along line VI-VI of the figure

  gure 5, - FIG. 7 shows a second section along the pressure channel along line VII-VII of FIG. 5,

  - Figure 8 shows a fifth example of a

  read presented in a similar manner to that of Figure 2, the body of the shutter member having a toothed profile, - Figure 9 is a cross section along the line IX-IX in Figure 8 along the chamber pressure,

  - Figure 10 shows a sixth example of a

  reading presented in a manner similar to that of FIG. 2,

  and whose second supply line is connected to the

  nal annular through a connecting channel in the organ

shutter.

  Description of the exemplary embodiments

  The first embodiment of a fuel injector according to the invention for internal combustion engines, shown in FIG. 1 and on an enlarged scale in detail in FIG. 2, comprises an injector body 3 housed

  in block 1 of an internal combustion engine, preferably

  rence in the breech; the injector body 3 penetrates with

  its lower end in the combustion chamber of the mo-

  internal combustion tor thus fed. The injector body 3 comprises a blind hole bore 7, axial, starting from a front surface 5, upper, remote from the combustion chamber; this drilling guides in axial sliding a shutter member 9 in the form of a piston. This closure member 9, shown on an enlarged scale in FIG. 2, comprises at its lower end, on the side of the combustion chamber, a sealing surface 11, conical, which cooperates with the valve seat surface 13 also tapered to

  the closed end of the bore 7. The closure member 9 includes

  carries, at the level of its body, a pressure shoulder 15 acting in the direction of the opening of the shutter member and projecting into a pressure chamber 17; this

  chamber is formed by an increase in the section of the per-

çage 7.

  A pressure channel 19 extending across the

  front surface 5 opens into the pressure chamber 17.

  By its other end, this channel is connected to a pipe

  fuel injection 21 shown schematically

  than in Figure 1; the pressure chamber 17 is supplied by this line from a high injection pump

  pressure not shown, with high pressure fuel.

  Between the pressure chamber 17 and the valve seat 13 there

  there is an annular channel 23 extending along the axis (an-

  axial ring) between the wall of the bore 7 and the body 9 of

  the shutter member; the fuel arrives through this

  nal from the pressure chamber 17 to the valve seat 13. On the side of the valve seat surface 13 opposite the annular channel 23, there are injection orifices 25 in the form of ejection holes which open into the combustion chamber of the internal combustion engine intended to be supplied. As shown in FIG. 1, the injector body 3 is fixed using a nut 27, axially against the injector support 29; the injector body 3 is separated from the support 29 by an intermediate washer 31. A valve spring 33 is placed in the support body 29 to act on the closure member 9 by means of a spring cut 35 and a compression spring 37,

  in the closing direction, against the valve seat 13.

  To supply a second fluid to

  preferably inject water, the injector body 3

  carries a second supply line 39 facing the ca-

  pressure nal 19 and extending obliquely from the front surface 5 into the pressure chamber 17. The

  second supply line 39 is connected by a connector

  feed line 41 which passes axially through the washer

  intermediate 31 and the injector support 29, being re-

  linked to a branch nozzle 43; this nozzle is itself

  even connected in a manner not shown to a pipe

water supply.

  The return or discharge of water in the direction of the connection nozzle 43 or of the transfer pump is prohibited by a non-return valve 45 opening in the direction of the injection orifice 25 in the supply line 41, preferably in the area of the washer

intermediate 31.

  The fuel injector according to the invention, for internal combustion engines, operates in the manner

  following: before the injection begins, water is supplied

  denies by supply line 41 and second line

  supply 39 to the pressure chamber 17 filled with car-

  0lo burant; the water transfer pressure is higher during the injection breaks than the static pressure of the residual fuel in the injector. The water transfer pressure is preferably between 30 and 100 bars while the residual fuel pressure is of the order of 20 bars and at most 70 bars. The water compressed in the pressure chamber 17 discharges the fuel which remains in the pressure chamber 17 and in part that of the annular channel 23 back in the pressure channel 19. It is only in the vicinity of the surface forming valve seat 13 there is some residual fuel remaining

  pure in the annular channel 23 while in the other parts

  parts of the annular channel and in the area of the pressure chamber 17 there is water or a fuel and water emulsion. At the start of a fuel injection, in the injector, the injection pump supplies, via the injection line 21 and through the pressure channel 19, fuel under very high pressure, preferably up to 1800 bars in the pressure chamber 17. The high pressure of the

  fuel acts, in a known manner, on the pressure shoulder

  15 of the shutter member 9 and moves it after exceeding the opening pressure against the return force of the valve spring 33, to lift from the seat 13. With the control of the opening of the opening section, it first passes pure fuel through the injection orifices 25 into the combustion chamber of the

  internal combustion engine to be powered; the com-

  bustion thus begins with a pre-injection. In connection with this pre-injection of pure fuel, part of the emulsion

  fuel / water from the annular channel 23 is injected to delay

  der then the second combustion which follows, during the continuation of the main injection, pure fuel. Then, by intermediate injection of the fuel emulsion

  rant-eau, the fuel injection is subdivided into one

  ble pre-injected quantity and an amount corresponding to the main injection. The second supply line 39 which supplies the water is closed hydraulically by the high pressure of supply fuel prevailing in the pressure chamber 17 so that during the main injection phase, the water cannot exit from the second supply line 39 to reach the pressure chamber

  17. The non-return valve 45 prevents the return of water in di-

  rection of the connection nozzle 43 or the pump

  transfer. As the pressure channel 19 and the second con-

  feed line 39 must allow flow rates of different amplitudes, the passage section of the pressure channel 19 is advantageously larger than the section of

  passage of the second supply line 39.

  At the end of the fuel injection, the high fuel pressure is cut in the injection line 21 so that the pressure prevailing in the pressure chamber 17 again drops below the opening pressure of

  the shutter member 9 and that the closing force of the res-

  fate 33 of the valve then suffices to again put the closure member 9 in abutment against the sealing surface 11 of the valve, against the seat surface 13 to close the injector. The fuel pressure drops in the injection line 21 and in the pressure channel 19 to pass again under the water supply pressure so that the water arrives again through the second supply line 39 in the pressure chamber 17 and

  parts of the annular channel 23 to expel the fuel therefrom

  rant in the pressure channel 19. This again gives a

  stratification of fuel and water as has been de-

  crit above in the pressure chamber 17 and in the case

nal annular 23.

  The second embodiment of the invention, shown in Figure 3, differs from the first example of

  embodiment shown in Figure 2 by a sleeve 47 sup-

  Plementary placed in the annular channel 23 which divides the annular channel 23 into a zone 49 radially inside and a zone 51 radially outside. These two zones 49, 51 are connected by a large number of holes 53 made in the sleeve 47. The sleeve 47 has, at its end

  facing the injection orifice 25, an annular flange

  laire 55 of increased diameter tightly sealing the

  sleeve 47 against the wall of the bore 7 so that the area ex-

  51 is closed towards the injection orifice

  25. The upper end entering the pressure chamber

  sion 17, of the sleeve 47 is biased, increasing towards the mouth of the second pipe

  39. In this way the amount of water that flows

  shore by the second supply line 39 is conducted in the outer area 51 of the annular channel 23 and then arrives through the holes 53 of the sleeve 47 in the area near the seat. Fuel returning through the pressure channel

  19, however, is mainly extended to the interior area.

  lower 49 of the annular canal 23, with the exception of the ex-

  51, so that it can arrive without obstacle and also

  as quickly as possible on the valve seat 13. The provision

  sition and the realization of the holes 53 in the sleeve 47 can be influenced by the mixture of fuel and water, making it possible to obtain an emulsion as advantageous

as possible.

  The third embodiment shown in Figure 4 includes, on the body of the shutter member 9

  entering the annular channel 23, a large number of

  longitudinal grooves 57, preferably six longitudinal grooves

  dinales 57. These axial longitudinal grooves 57 extend

  between their upper end to the pressure chamber

  sion 17 and open with their lower end facing the injection orifices 25, in an annular volume

  59, lower, made in the hole 57. This volume annu-

  the area 59 of the annular channel 23 is formed by a narrowing

  he lies from the section of the obturation organ; this channel is separated from the surface 13 forming the valve seat by an annular rib 61 which remains. Thanks to the realization of

  body of the shutter member according to FIG. 4, it is pos-

  able to supply fuel and water, practically without separation, to the annular chamber 59 in order to achieve good

  stratification of fuel as well as water and fuel

rant.

  The fourth example of the injection

  fuel according to the invention, shown in Figures 5

  to 7 differs from the third embodiment shown

  felt in FIG. 4 by the shape of the body of the shutter member in the region of the annular channel 23. In the area of the annular channel 23, the body of the shutter member 9 has a four-sided section 63 as shown in the sectional view of Figure 6. In addition, the section of the pressure chamber 17 is oval in shape according to the sectional view of Figure 7 and the second supply line 39 and the pressure channel 19 each end opposite the far ends of the pressure channel section

  oval shape, to reach the pressure chamber 17.

  The fifth embodiment shown in FIGS. 8 and 9 of the injector according to the invention comprises a shutter body 9 with toothed section 65 in the

  zone of the annular channel 23 extending axially from the cham-

  pressure bre 17 into the annular volume 59. In addition, the pressure chamber 17 has a section in the form of an oblong hole (FIG. 9) which is a sectional view of FIG. 8. In the sixth embodiment shown in Figure 10 the water supply is from the second supply line 19 unlike the previous embodiments by a connecting channel in the closure member 9; the water introduced does not pass through the pressure chamber 17. The second supply line

  39 opens into the valve body 3, above the chamber.

  pressure bre 17 in the blind bore 7; in the mouth area, there is an annular volume between the closure member 9 and the wall of the bore 7 which is formed in the exemplary embodiment by an annular groove 67 in the closure member 9. A connecting channel 69, formed by two blind holes, connects the annular groove 67 of the closure member 9 to the annular channel 23 opening out below the pressure chamber 17. In the area of the annular channel 23 there are two surfaces ground, axially, among

  which the first ground surface 71 extends from the cham-

  pressure bre 17 into the annular volume 59 and con-

  1l duit the fuel arriving through the pressure channel 19 towards the valve seat 13. The second ground surface 73 begins

  in the area of the mouth of the connecting channel 69 below

  under pressure chamber 17 and also extends to

  in annular volume 59. Water arrives in the annular canal

  laire 59 from the second supply line 39, through the connecting channel 69 and the second ground portion 73; the connecting channel 69 forms a bypass line to the pressure chamber 17. The sixth embodiment has the advantage that the water thus supplied can be conducted separately in the annular channel 23 and thus gives a very homogeneous stratification of fuel , water, then fuel again, allowing very precise control of

  the pre-injected amount and the main injection amount

fuel blade.

RE V E N D I C A T IONS

  1) Fuel injector for an internal combustion engine comprising a shutter member (9) guided in axial sliding in a bore (7) of the valve body (3) and the end of which, on the side of the combustion chamber, has a valve sealing surface (11) which cooperates with a valve seat surface (13) integral with the body of the injector for controlling the injection section, a pressure shoulder (15) cooperating in the direction of the opening of the shutter member (9), this shoulder

  being provided on the rod of the shutter member (9), penetrated

  Trant in a pressure chamber (17) whose section widens, a pressure channel (19) capable of being connected to a high pressure fuel source opening further into this pressure chamber, the pressure chamber ( 17) formed between the rod of the shutter member and the wall of the bore (7) being connected by a

  axially extending annular channel (23) at the surface formed

  mant valve seat (13), and a second supply line (39) in the injector body (3) through which a second fluid is supplied to the injection section of the injector, characterized in that the second supply line (39) extends completely into the body (3) of the injector and opens directly into the pressure chamber (17) or at least near the pressure chamber (17) in a delimited volume Between

  the shutter member (9) and the wall of the bore (7).

  3 (} 2) Fuel injector according to claim 1, characterized in that the second fluid is water supplied to the injection section. 3) Fuel injector according to claim 1, characterized in that

  the second supply line (39) has a cross-section

  smaller than that of the fuel pressure channel (19).

  4) Fuel injector according to claim 3, characterized in that

  the second supply line (39) is connected to a connection nozzle (43) of a transfer line by a supply line (41), a non-return valve (45) 10 opening in direction of the injection orifice (25) being provided in the supply line (41).

   ) Fuel injector according to claim 1, characterized in that the fuel pressure in the pressure channel (19), during the injection phase, is greater in the injector than the pressure of the second fluid in the second

supply line (39).

  6) Fuel injector according to claim 1, characterized in that the pressure of the second fluid in the second supply line (39) is greater during the breaks

  injection of static fuel pressure into the

pressure nal (19).

  7) Fuel injector according to claim 1, characterized in that the pressure chamber (17) has an oval section and the second

  supply line (39) and the car pressure channel

  burant (19) open in opposite positions each time at the end furthest from the section of the pressure channel. 8) Fuel injector according to claim 1, characterized in that a sleeve (47) is placed in the axial annular channel (23)

  which subdivides the annular channel (23) into a radiating zone (49)

  internally and an area (51) radially to

  outside, these zones (49, 51) being connected by a large number of holes (53) produced in the sleeve (47).

  9) Fuel injector according to claim 8, characterized in that the sleeve (47) is tightly tightened against the wall of the bore (7) at its end facing the valve seat (13) and the end facing the pressure chamber 10 (17) is slanting in the rising direction towards

  the mouth of the second supply line (39).

   ) Fuel injector according to claim 1, characterized in that the rod of the shutter member (9) comprises, in the area

  of the annular canal (23), a large number, in particular six

longitudinal ribs (57).

  11) Fuel injector according to claim 1, characterized in that the rod of the closure member (9) has a cross section

  four sides (63) in the area of the annular channel (23).

  12) Fuel injector according to claim 1, characterized in that the rod of the closure member (9) has a section

  toothed (65) in the area of the annular channel (23).

  13) Fuel injector according to one of claims 10

at 12,

characterized in that

  the shutter member (9) present, at the level of the annular channel

  area (23), a portion narrowed between the lower end of the profiled surfaces (57, 63, 65) facing the valve seat on the stem of the closure member and the sealing surface (11), these surfaces forming an annular volume

  of enlarged section (59) in the annular channel (23).

* 14) Fuel injector according to claim 1, characterized in that

  the second supply line (39) opens into the per-

  hole (7) above the pressure chamber (17) and in the mouth area there is an annular volume between the member

  shutter (9) and the wall (7) of the bore, hence a

  nal link (69) passing through the closure member (9), this channel opening into the annular channel (23) downstream,

  below the pressure chamber (17).

   ) Fuel injector according to claim 14, characterized in that the rod of the closure member (9) comprises, in the region of the annular channel (23), at least two ground surfaces which open into the annular volume (59 ) and the first ground surface (71) of which comes into the pressure chamber (17)

  with its upper end and whose second movable surface

  lée (73) ends below the pressure chamber (17), the connecting channel (69) opening in the second

  ground part (73) of the shutter member (9).