FR2660018A1 - ELECTROMAGNETIC INJECTOR. - Google Patents

Abstract

To prevent deviations from one example of an injector to another, as is the case with known injectors making it possible to dose and spray fuel, the injector according to the invention is made in such a way that 'Between the fuel metering valve (2) and the spray device (9) there is a flow measuring system (11) which consists of a measuring cylinder (10), a free piston (13) and a system ( 14) free piston stroke detector. It is thus possible, by determining the quantity of fuel to be injected flowing through the injector (1), to strictly comply with the preset nominal quantity of fuel. The use of the injector of the invention ensures trouble-free, economical and low-pollution operation of internal combustion engines.

Description

Electromagnetic injector

  The present invention relates to an electric injector

  magnet for introducing fuel into the suction pipe of an internal combustion engine and equipped with a fuel metering valve actuated by a frame, which is moved against the force of a spring under the effect of a magnetic force, and of a spraying device produced in the form of a

  breather and protruding into the suction manifold.

  An injector of this kind is described for example in the German patent application published Al 2501283 and is intended there to ensure, thanks to the presence of a metering valve and a spraying device mounted downstream

  of the latter, an exact dosage and preparation

fuel.

  This certainly seems to be assured for a single in-

  jet nozzle but as soon as several injectors are used deviations from one copy to another result as a result of which, in the case of a polycylinder internal combustion engine, unequal quantities of fuel are injected into the suction pipe and it risks

  produce an uneven combustion which has notoriously

  sequence of making exhaust fumes toxic.

  Starting from this state of the art, the pre-

  sente invention aims to achieve the injector indicated above in such a way that differences between different examples of injector have no effect on the speed of

  engine operation or do not occur at all.

  This goal is achieved, for an electro-injector

  Genetics intended to introduce fuel into the suction pipe of an internal combustion engine and equipped with a fuel metering valve actuated by an armature, which is moved against the force of a spring under the effect of a magnetic force, and of a spraying device produced in the form of a breather and protruding into the suction pipe, according to the invention by the fact that between the metering valve and the device spraying system is fitted a flow measurement system which consists of a measuring cylinder, a free piston and a system for detecting the stroke of the

free piston.

  In a preferred embodiment of the invention,

  vention the fuel metering valve has a first service position, in which a part of the measuring cylinder disposed on one side of the free piston and communicating with the spraying device is in communication with a fuel supply system, and another part of the measuring cylinder arranged on the other side of the free piston is in communication with a fuel evacuation system, and a second service position in which the part of the measuring cylinder cited

  lastly communicates with the fuel supply system

  ble and the part of the measuring cylinder cited first does not

  not communicate with the fuel supply system.

  In this embodiment it can before-

  It should be provided that the fuel metering valve has a shutter member which, actuated by the armature or produced as an armature and pierced axially, cooperates

  by one of its front faces with a watertight surface

  chewiness and acts with a collar on a sealing plate

  a communication channel so as to control the commu-

  indications between the fuel supply system and the part of the measuring cylinder mentioned first and, by its other front face, cooperates with a flat seat and controls the communication between a discharge chamber communicating with the fuel evacuation system, or the room

  compression, and said other part of the cylinder measured

  ror, while there is between the two cited parts of the measuring cylinder a bypass channel which opens, in the neutral position of the free piston, provided that the compression chamber and the part of the measuring cylinder

  which is in communication with the spraying device

tion communicate with each other.

  In a variant of this embodiment the bypass channel is provided in the free piston and has a differential pressure valve, the neutral position being defined by a projection forming a stop (mechanical locking) In another variant the bypass channel is provided in the wall of the injector and defines the neutral position when opened by the

  free piston (hydraulic lock).

  An advantageous characteristic of the invention consists in that the aforementioned communication channel is

  throttled with respect to said bypass channel.

  In the aforementioned second operating position of the fuel metering valve, the bypass channel formed in the wall of the injector is advantageously

  closed by one of the front faces of the shutter member.

  The free piston stroke detection system

  works with laser beam, ultrasound, induc-

tion or ability.

  The invention is explained in more detail below.

  below using an example embodiment illustrated in the accompanying drawing in which:

  Figure 1 shows schematically the construction

  tion of an injector according to the invention in combination with a fuel supply and evacuation system; and

  Figure 2 shows another form of realization.

  sation of the injector in Figure 1.

  Figure 1 shows, in section, an electric injector

  tromagnetic 1 consisting of a metering valve

  bustible 2, which is mounted in a compression chamber 4 communicating with a fuel supply system 3 and has a frame 6 serving as a shutter member 5 and

  that can be moved against the strength of a res-

  leaves by an electromagnetic system 7 At its end projecting into a suction pipe of an internal combustion engine the injector 1 comprises a device

  spray 9 produced in the form of a breather 8.

  In a conduit 10 provided between the metering valve 2 and the

  spray device 9 is mounted a measuring system

  re fuel flow 11, which consists of a cy-

  measuring tape 12 arranged inside the conduit 10 thus

  if by a free piston 13, the displacement of the piston li-

  bre 13 being detected by a race detection system

  14 which operates with a laser beam, ultrasound, by induc-

  tion or capacity and whose values are treated in a

  control unit associated with the internal combustion engine

born.

  The frame 6 or the shutter member 5, received in a frame guide 15, is pierced axially and penetrates with one end into the compression chamber 4 and with its other end into a discharge chamber 16 which

  (via conduits) communicates with a system

  fuel evacuation me 17, which leads to the reservoir

see fuel.

  The shutter member 5 has a collar 18 sol-

  licit by a spring, so that the shutter member 5 is pressed with a front face 19 against a flat seat

  , thus closing the duct 10 tightly in relation to

  port to the discharge chamber 16 The end projecting into the compression chamber 4 cooperates via another end face 21 with a sealing surface 22 of a cylindrical projection when the magnetic forces are effective, so that a seal plate

  23 loaded by a spring is lifted by an

  be collar 24 of the shutter member 5 and a channel

  munication 25 opens towards the compression chamber 5 while the channel formed in the obturator 5

  found closed towards the compression chamber 4.

  The free piston 13 divides the measuring cylinder 12 into a cylinder part 26, which communicates with the communication channel 25 and the spraying device 8, 9, and a cylinder part 27, which communicates with either

  the discharge chamber 16, either with the compression chamber

  sion 4 depending on whether the shutter member 5 occupies one or the other of the two possible service positions The piston

  free 13 has a bypass channel 28 with a valve

  eg at differential pressure 29 The top dead center position of the free piston 13 is defined by a projection 30 forming a stop The communication channel 25 has a

strangled part 31.

  Figure 2 shows, as another variant, the

  arrangement of the bypass channel in the wall of the

  junction, the bypass channel 28 'being, in the second operating position of the shutter member 5, closed relative to the discharge chamber 16 by the front surface 19 of the shutter member 5 or, as shown in dotted lines , which can open into part 27 of the measuring cylinder When the bypass channel 28 'opens in part 27 of the measuring cylinder due to the free piston 13, the latter is locked hydraulically, this

  which will be discussed in more detail in the description

operation.

  When the injector 1 according to the invention is used in an internal combustion engine comprising several cylinders, each suction pipe leading

  to the cylinders is fitted with an injector 1, thus allowing

  if obtaining a sequential and selective injection

  brought to the ignition order and which is controlled by the device

  similar electronic control above according to a program

  The fuel supply system 3 is made up of

  killed by a fuel pump, a pressure regulator and a return channel to the fuel tank (not shown) and prepares in the compression chamber 4 of the

  fuel subject to a preset pressure.

  The electronic control unit delivers to

  different injectors a control signal which is applied

  as for the electromagnetic system 7.

  In the illustrated embodiment of the

  jector 1, which is one of several forms of realization

  sation which may be envisaged in the context of the invention

  tion, the injection into the suction pipe is always carried out when the electromagnetic system 7 is

  off, as shown in Figure 1.

  In this phase the communication channel 25 and the bypass channel 28 are closed and the part 27 of the measuring cylinder is subjected to the fuel pressure.

  located in the compression chamber 4 This pressure

  sion charges the free piston 13 so that it exerts pressure on the fuel contained in part 26 of the measuring cylinder Since this fuel cannot be evacuated via the closed communication or bypass channel, the pressure increases to a value for which the breather opens From this moment the pressure in part 26 of the measuring cylinder no longer increases so that the quantity of fuel brought into part 27 of the measuring cylinder does not lead to no pressure increase but pushes the free piston 13

  out of its rest position and in part 26 of the cylinder

dre measurer.

  The free piston 13 is advantageously made of a material having the same density as that of the fuel and does not cause significant displacement during displacement since there can be no difference

  pressure between parts 26 and 27 of the cylinder measured

  The amount of fuel which is displaced during movement of the free piston 13 in part 26 of the measuring cylinder corresponds to the stroke made by the piston.

free 13.

  This race is now determined permanently

  by the stroke detector system 14 and is supplied as a signal to the control unit and evaluated in

  this until the amount of fuel to be injected

  ter preset is reached, after which a signal is

  delivered to the electromagnetic system 7.

  Therefore the frame 6 or the shutter member 5 (to be brought into a first service position) is moved against the force of a spring and pushed with the front face 21 against the surface sealing 22 of the cylindrical projection, thus allowing at the same time the collar 24 to lift the sealing plate 23 and the front face 19 of the sealing member 5 to release the

  flat seat 20, so that part 26 of the cylinder

  reur communicates with the compression chamber 4, and the part 27 of the measuring cylinder communicates with the chamber

discharge 16.

  When part 27 of the measuring cylinder opens in the discharge chamber 16, which communicates with the

  fuel evacuation system 17 where there is a pres-

  sion lower than that of the compression chamber 4 and the opening pressure of the breather 8, the pressure in the part 26 drops suddenly so that the breather 8

  closes From the compression chamber 4 of the fuel

  ble is now discharged through the open communication channel 25 in part 26 so that the free piston 13 is loaded and moves in the direction of part 27 communicating with the discharge chamber 16 until the free piston 13 abuts against the projection

  forming stop 30, which defines its neutral position.

  Because the pressure in part 26 increases before

  again feels the differential pressure valve 29,

  whose opening pressure is lower than that of the re-

  niflard 8, opens in this neutral piston neutral position, so that fuel can flow from

  the compression chamber 4, passing through the discharge channel

  rivation 28 formed in the free piston 13, in the discharge chamber 16 and thus rinses the injector 1 so that hot fuel and vapor bubbles, possibly

  formed, can be evacuated via the system

  fuel evacuation valve 17.

  In the embodiment of Figure 2 the

  bypass channel is arranged in the wall of the injection

  When the free piston 13 is loaded by increasing pressure and moves the bypass channel 28 'opens

  so the pressure suddenly drops and moves it

  end, the neutral position is thus reached

  tinted and locked hydraulically Since the communication channel 25 is throttled relative to the bypass channel 28 'by the throttled part 31, it is established in the two embodiments in this

  phase a pressure which is lower than the pressure of

breather 8.

  If the neutral piston position has now been reached, the electromagnetic system 7

  is switched off by a signal from the control unit

  of, then the operation according to the second position of

  service, as described above, resumes.

  The advantages of the present invention are re-

listed below.

  The injector according to the invention allows, by

  the effective value of the quantity of fuel

  ble to inject flowing through the injector, respec-

  rigorously ter the nominal quantity of fuel pre-

  established. Known disruptive factors that exerted

  so far a strong influence, namely the aging-

  wear, deposits, etc.

  little or no influence on the injection conditions.

  If several injectors are used, differences between different examples of injectors observed so far have little influence and now remain within the limits of what is due to the stroke detection system By rinsing of the injector during the phases without injection, the heating of the fuel accompanied by the formation of vapor bubbles is obtained during

  engine operation can no longer occur.

  The injector according to the invention allows a mo-

  internal combustion engine, for example in road vehicles, to operate without incident, economically and

  so as to release only a few harmful materials.

Claims (7)

  1 Electromagnetic injector intended to introduce fuel into the suction manifold of a   internal combustion and equipped with a metering valve   bustible actuated by an armature, which is moved against the force of a spring under the effect of a   magnetic force, and a spray device   read in the form of a breather and protruding into the suction pipe, characterized in that it is mounted   between the metering valve (2) and the spraying device   tion (9) a flow measurement system (11) which is constituted   killed by a measuring cylinder (10), a free piston (13) and   a system (14) for detecting the free piston stroke.   2 injector according to claim 1, character-   that the fuel metering valve (2) pre-   feels a first service position, in which a part (26) of the measuring cylinder disposed on one side of the free piston (13) and communicating with the spraying device (9) is in communication with a fuel supply system ( 3), and a part (27) of the cylinder   meter located on the other side of the free piston (13) including   fitted with a fuel evacuation system (17),   and a second service position in which the latter   third part (27) of the measuring cylinder is in communication   with the fuel supply system (3) and the other   tie (26) of the measuring cylinder is not in communication   with the fuel supply system (3).   3 injector according to claim 2, charac-   characterized in that the fuel metering valve (2) pre-   feels a shutter member (5) which, actuated by the armature   (6) or made in the form of an armature and axially drilled   Lement, cooperates by a front face (21) with a surface   seal (22) and acts with a collar (24) on a plate   obturator cap (23) of a communication channel (25) so as to control the communications between the fuel supply system (3) and the part (26) of the measuring cylinder, and cooperates by another front face (19 ) with a flat seat (20) and thus controls the communication between a discharge chamber (16) communicating with the fuel evacuation system (17) or the compression chamber (4) and the part (27) of the measuring cylinder, while there is between the two parts (26, 27) of the measuring cylinder a bypass channel (28; 28 ') which in the neutral position of the free piston opens when the compression chamber (4 ) and the part (26) of the measuring cylinder, which is in communication with the device   spray, communicate with each other.   4 injector according to claim 3, charac-   terized in that the bypass channel (28) is arranged   in the free piston (13) and has a pressure valve   differential drive (29), the neutral position of the latter being defined by a projection forming a stop (30) (mechanical locking).   Injector according to claim 3, characterized in that the bypass channel 28 'is arranged in the wall of the injector and defines, in the event of opening   by the free piston (13), the neutral position (ver- hydraulic rusting).   6 Injector according to any one of the claims   cations 3 to 5, characterized in that the communication channel   tion (25) is throttled relative to the bypass channel (28, 28 ').   7 Injector according to any one of the claims   cations 3, 5 and 6, characterized in that in the second operating position of the fuel metering valve (2) the bypass channel (28 ') is closed by the face   front (19) of the shutter member (5).   8 Injector according to any one of the claims   previous cations, characterized in that the free piston stroke detector system (14) operates by radius   laser, ultrasound, induction or capacity.