FR2466628A1 - FUEL SUPPLY DEVICE FOR INTERNAL COMBUSTION ENGINE - Google Patents

Abstract

This fuel supply device for a compression ignition engine comprising pairs of injectors 19, 20 and 21, 22, comprises a pair of pumps 9 which respectively supply the fuel to the pairs of injectors. Each pump is combined with a distributor 60 which serves to direct the output of this pump to one or the other of the injectors of the pair of injectors combined with this pump. (CF DRAWING IN BOPI)

Description

i

  The present invention relates to devices for

  fuel supply for spark-ignition engines

  particularly those of the direct injection type

  These devices include electromagnetically controlled fuel pumps. When fuel is injected directly into a combustion chamber formed by the cylinder of a compression ignition engine, it is necessary to supply the fuel at a higher pressure than in the case of a fuel injection engine.

  indirect injection type engine in which the fuel

  ble is distributed to a combustion chamber which is connected to the engine cylinder bypassing. In addition, with the direct injection engine type, it is necessary to use an injector of the inwardly opening type instead of a

  type injector opening outwards that is possible

  to use on indirect injection engines.

  It has been described in British Patent Application No.

  7 912 311 an electromagnetically controlled pump in which

  the injector is of the type opening outwards and is

  incorporated in the body of the pump. If one demands a

  sion, it is obviously necessary to increase the size of the electromagnetic device so as to be able to

  develop a higher fuel pressure for one

  lume given of fuel debited. Because of this, the dimension and

  the weight of the pump are increased which increases the difficulties

  the problems encountered in mounting several pumps of this type on an engine and also significantly increases the cost

  of the fuel supply device.

  Since, in the case where the device comprises pumps equal in number to the number of the cylinders of the engine, each pump must not pump the fuel until every two revolutions of the engine, it has been proposed to halve the number of the pumps. and to constrain each pump to supply the fuel to two injectors in turn. Like this,

  a considerable saving is made on the feeding device.

engine fuel.

  According to the invention, a fuel supply device for supplying fuel to an engine with

  compression ignition comprises injectors which, in

  vice are mounted on the engine associated so as to direct

  the fuel to the combustion chambers of the engine

  respectively, one or more electromagnetic pumps for delivering the fuel under pressure, and a valve device associated with the pump or pumps respectively so that, in use, the pump or each pump provides

  fuel with two injectors in turn and synchronously

  me with the operation of the engine to which the device is combined. Other features and advantages of the invention

  will appear in the following description. the

  attached drawings, given by way of example only; 1 is a side elevational view in vertical section of a pump; FIG. 2 is a schematic view of a device

  fuel supply for a four-cylinder engine

  ders. According to the embodiment shown on the

  Fig. 1, the device comprises an electrically controlled pump 9

  magnetic which includes a body 10 having as a whole

  a cylindrical shape. This body 10 comprises a first

  11 which protrudes axially on this body and a second

  boss 12 which protrudes laterally on the body. The

  two bosses have peripheral threads.

  The first boss is hollow in shape and has a

  inner shoulder 13 against which the glue

  This barrel extends with clearance in a cylindrical chamber 15 formed inside the body.

  and the collar of the barrel is held in abutment on the

  13 by means of a cup-shaped element 16 which delimits an outlet 17. This element 16 is held in abutment on the flange of the barrel by means of a retaining nut.

  18 which is screwed onto the boss 11.

  In the bore formed in the barrel of the pump is

  housed a pumping diver 23 and this diver extends to the

  the end of the barrel and has a flange

  which end and the end of the barrel is interposed a res-

  The coil end of the plunger has radial grooves and the movement of the plunger under the action of the spring 24 is limited by the contact between the plunger and an abutment ring 25 which is

  resting against a shoulder formed in the body. In addition

  their, the diver has a cavity that receives the

mity of a push rod 26.

  The fuel is distributed to the bounded space in

  the body in a way that will be explained later. This fuel

  tible is under a low pressure and, during the movement of the plunger outwards under the action of the spring 24, the

  fuel is sucked into the chamber delimited by the barrel.

  let go of the pump and flows through a check valve while, when the plunger moves inward,

  the non-return valve remains closed and the fluid is then re-

stepped through exit 17.

  The check valve includes a movable shutter 27

  having a tail 28 which is slidably mounted in the

  damage to the barnel of the pump. This movable shutter also comprises a head 29 which has a larger diameter than the

  tail and, in the position of closing the shutter mo-

  bile, this head is supported on a shaped annular edge 30

  at the end of an enlarged portion of the bore of the barrel.

  The movable shutter is pushed back to the closed position

  by a compression spring 31 and is traversed by

  a drilling-32. In addition, the barrel 14 comprises in the re-

  adjacent to its flange two radial orifices 33 which communicate at their outer end with the space delimited between the outer periphery of the barrel and the

  wall 15 of the chamber formed in the body. At their extremes

  the ports communicate with a circumferential groove

  conferred 34 formed in the periphery of the tail 28 of the movable shutter. The shank 28 has a length such that towards the end of the diver's stroke, the diver encounters the tail and raises the movable shutter by overcoming the action of the spring 31. When this occurs, the distribution of the fuel by the outlet 17 ceases and the remaining volume of fuel discharged by the plunger flows through the orifices 33.

  When the diver is brought back under-

  of the spring 24, the movable shutter 27 of the non-return valve

  turn remains in a position in which the holes 33

  are in communication with the barrel bore and where the head is

  29 is lifted from the edge 30. The reason is that the fuel

  pressure under pressure ejected from the aforesaid chamber acts on the head of the movable shutter and the fuel penetrates

  in the bore occupied by the diver. This flow of com-

  The buzzard continues until either the movement of the plunger is interrupted by the stop ring, or rather, as will be explained later. As soon as the movement of the plunger is interrupted, the fuel can no longer enter the bore and the hydraulic pressures acting on the movable shutter are balanced. As a result, the movable shutter moves under the action of the spring 31 until 'that has

  the head meets the above-mentioned edge and that communication with

  the holes and the bore is interrupted.

  To ensure the movement of the plunger of the pump which occurs by overcoming the action of the spring 24 and in the direction tending to push the fuel through the outlet 17, there is provided an electromagnetic device which prints its movement to the plunger by the intermediate of a push rod 26 which extends through a bore 34a formed in a core 35. This core is formed of a magnetizable material and it is

  advantageously come from material with the body of the pump. always

  it can also be realized in the form of a -

  separate piece, in which case it is not necessary that the body be made of a magnetizable material. This core as a whole has a frustoconical shape and it comprises a series of circumferential grooves 36. These grooves delimit between them circumferential ribs 37 and the ribs are removed from the body 10, plus their diameter is small. In addition, the width of the grooves 36 increases with the distance that separates them from the body 100. The outer surface of the ribs is inclined on the axis of the core and each groove contains a winding 38. The windings, which are multi-turn windings, are advantageously connected in series so that, when the electric current flows through these

  windings, the direction of current flow in a winding

  either the opposite of the flow direction of the current in the adjacent windings. In this way, when the electric current flows through the windings, the adjacent ribs are magnetized with opposite magnetic polarities. Advantageously, one end of the series-connected windings is connected to the core while the other end is connected to a terminal 39 which is carried by a block 40

  in insulating material of electricity, which is attached to the body.

  The nucleus is surrounded by a frame 41 which is also

  made of a magnetizable material but which has a thin section. The frame 41 can be considered as composed of several circles or collars of decreasing diameters which are connected to each other by inclined parts such as

  that represented in 42. The internal faces of the parts

  are approximately parallel to the aforementioned faces of the ribs 37. The armature is in the form of a bucket and its

  bottom is pierced with two holes 43 and a central hole which

  a plug 44 in which is housed the end of the

  push rod 27 which is opposite the pump barrel.

  When the windings are excited, the armature goes down to reduce the reluctance of the interfering between

  ribs and inclined portions 42 of the frame, and

  thus me a movement to the pumping diver 23.

  The armature is surrounded by a hollow cap 45 which is formed of a non-magnetic material and is advantageously constituted by a zinc-based alloy casting. For convenience, the outer peripheral surface of the hood has a shoulder 46 and the side surfaces thereof.

  cover, so as to allow the removal of

  milk the mold cavity. The inner surface also has a stepped shape and is shaped to guide the armature in its axial movement. The end part of the hood, that is to say the part that extends between

  the outer shoulder and the body 10, has four ribs

  47 and between these ribs are formed cavities. As explained above, to allow the casting of the mold to be extracted from the mold, the internal surfaces have a draft and, after demolding,

  ribs 47 so as to delimit

  lindriques which extend parallel to the axis of the nucleus. Of

  this way, we form four bearing surfaces 48 on the-

  which frame carries at its widest end.

  The hood is provided with four other ribs 49 which also has a convergent shape provided during its manufacture. The internal surfaces of the ribs are machined to form cylindrical bearing surfaces which

  are in contact with complementary surfaces of the arma-

  ture that are closer to the narrow end of this

  frame. The open end of the hood is closed by a

  non-metallic closure member 51 which has in its

  seems the shape of a bowl. The wall of this iron element

  in the hood and its end portion is in

  contact with a sealing ring arranged against a shoulder

  adjacent to the ribs 49. The closure element 51

  is restrained by a deformation-appropriate of the part of ex-

  Hood tremity and the volume bounded inside the hood

  is connected to a fuel inlet 52 formed in the

  In operation, the fluid can flow from the bottom up

  on the inner surface or on the outer surface of the armament

  Through the holes 43, stil has flowed upward on the outer surface of the frame, and then down into the bore 34a to reach the bore 50 of the body. In this way, the cooling of the windings is ensured by the fuel.

  The skirt of the end closure element 51 pre-

  in its outer peripheral surface a circumferential groove

  55. In the groove is housed an electric winding

  that 56 to a single layer whose ends are connected

  has terminals 57 carried by the end closing element

  you. The frame 41 carries a ring 58 made of a con--

  conductor of electricity, and, when supplying a current

  alternatively to the winding 56, eddy currents

  slow in the ring 58, causing a change in the

  The amplitude of the variation of the inductance depends on the length of the portion of the ring 58 which lies within the limits of the winding and, since the ring is mounted on the coil. the armature, the value of the inductance gives an indication of the axial position of the armature. In operation, if it is necessary to debit the maximum volume of fuel, the plunger 23 is then allowed to describe its maximum stroke under the action of the spring 24.

  windings can be de-energized immediately after the

  fuel has occurred or they may be de-energized some time before the moment the ejection

  fuel is necessary, provided that the fuel is

  tible has sufficient time to penetrate into the

  laceration of the pump barrel. If it is necessary that the pump delivers less than its maximum fuel volume, the return movement of the armature effected under the action of the spring 24 must then be stopped in any intermediate position. The transducer formed of the winding 56 and

  of the ring 58 gives an indication of the position of the plon--

  and using the signal provided by the transducer, it is possible to partially excite the windings when the plunger has described the desired stroke. This partial excitation of the windings creates a sufficient force to retain the armature by overcoming the action of the spring 24 but it does not subject the fuel contained in the outlet

  17 at a noticeable pressure. When the distribution of

  tible is necessary, the windings are completely

  and the fuel flows through the outlet until the movable shutter head 29 is lifted from its seat, the filling of the bore can occur at any

  moment after the end of the fuel distribution and a-

  that the next distribution is necessary. Toute-

  It should be borne in mind that filling the bore with fuel requires a finite time and that

  therefore, if it is decided to fill this bore immediately

  Before fuel distribution is necessary, sufficient time should be allowed for the

filling can occur.

  Referring now to FIG. 2, it can be seen that the feed device comprises four injectors 19, 21, and 22 and that, in use, these injectors are mounted in the cylinder head of the engine to which the feed device is combined so as to inject the fuel into the injectors.

  combustion chambers delimited respectively by the

  to engine cylinders. The injectors are represented

  schematically as being of the type opening towards the

  with movable shutters 60 loaded with

  61 spells that tend to apply them in contact on their seats. Two pumps 9 such as those described above are provided, one of the pumps supplying the fuel

  to injectors 19 and 20 in turn and the other pump supplied

  injecting fuel 21 and 22 in turn. The

  outlets 17 of the pumps 9 are respectively connected to the

  two inverter distributors which are themselves

  connected respectively to the injectors. As we have

  Each inverter distributor includes a spool 61 having two spaced spans 62, 63 for controlling the flow of fuel through the outlet ports of the dispenser. The spool is loaded by a spring in one direction and is moved in the opposite direction by an electromagnetic actuator 64, the device described having two of these actuators. As will be seen, the adjustment of the combined spool to the pump which supplies the fuel to the injectors 19 and 20 is such that, when the fuel is discharged by the pump 9, it flows towards the injector 19. the device 64 is excited, the drawer moves to the other position in which the

  fuel is distributed by the pump to the injector 20.

  The actuating devices 64 are electrically controlled

  by the control device which is provided for the pumps in such a way that fuel is sent

  to the engine cylinders in turn and at appropriate times.

  However, the drawer 61 may possibly be mechanically connected and controlled by a single device but this

  is not the preferred arrangement because of the difficulty of

  to establish a mechanical link between the

inverters.

  It is desirable that the pumps are mounted as close as possible to the reversing distributors. They can

  be directly attached to the bodies of the distributors or

  linked to these bodies by small lengths of high pressure tubes. By using two pumps such as those described, we obtain a significant reduction in the cost of the installation compared to cases where a combined pump-injector group is provided for each combustion chamber of the engine. Well

  that the device described above is mainly intended

  for use with a direct injection engine, it is naturally possible to use the same arrangement for a

  indirect combustion engine with the form of injectors

  in the case of injectors of the opening type

  inside or outward-opening type.

he

Claims (4)

  1 - fuel supply device for   compression ignition device, this device being characterized   characterized in that it comprises injectors (19) which, in use, are mounted on the engine to which the device is combined to feed the fuel into the combustion chambers   of the engine respectively, one or more pumps (9) to   electromagnetic supply used to supply the fuel   under pressure, and respective distributors (60)   pump (9) or pumps (9) in such a way that   in operation, the pump or each pump provides the   two injector fuel (19) alternately at times   coordinated with the operation of the engine.   2 - fuel supply device according to claim 1, characterized in that the distributor or   at least one of the distributors is controlled by a   tif with electromagnetic actuation.   3 - Fuel supply device next   Claim 2, characterized in that the other   scorers are mechanically connected to the electromagnetic interference.   Fuel supply device according to Claim 1, characterized in that the distributor or each distributor comprises a spring-loaded spool and an electromagnetic actuator for   move the drawer against the action of the spring.