FR2476225A1 - FUEL INJECTION PUMP APPARATUS - Google Patents

Abstract

FUEL INJECTION PUMPING APPARATUS INCLUDING A DISTRIBUTOR 28 AXIALLY MOVABLE TO VARY THE QUANTITY OF FUEL DELIVERED, A TRANSDUCER INDICATING THE AXIAL POSITION OF THE DISTRIBUTOR, AND WHICH INCLUDES TWO DETECTORS 54 AND 56 DETECTANT PASSAGE DETECTURES TWO PARTS 14A AND 58 THAT CAN BE DRIVEN IN ROTATION WITH THE DISTRIBUTOR. THE ANGULAR DISTRIBUTION BETWEEN THESE TWO PARTS, AND THEREFORE THE PHASE BETWEEN THE SIGNALS PROVIDED BY THE DETECTORS VARIES WHEN THE DISTRIBUTOR IS MOVED AXIALLY, THIS VARIATION IS CAUSED BY THE BETWEEN THE DISTRIBUTOR AND PART 58 BY ERGOTIDAL GROOVING 61 AND PART 58 62.

Description

The present invention relates to a pumping apparatus.

  pag; e fuel injection for internal combustion engine, comprising a body, a rotary distributor mounted inside of the body and arranged to be, in service, driven in synchronism with the engine with which the device is associated, a bore transverse formed in the distributor, a plunger located in this bore, a

  cam follower located at the outer end of the plunger

  to cooperate with a cam surface formed on a cam ring surrounding the distributor, means for

  stop to limit the displacement of the plunger towards the ex-

interior, these abutment means comprising internal surfaces

  respectively clinched on the following

  in one part, this part being able to rotate with the distributor, but being axially fixed inside

of the body, whereby when the dispenser is moved

axially inside the body, the distance by which the plunger can move outward when

  fuel is brought to the bore varies, means of not-

  wise to bring fuel to and from the bore

  evacuate during rotation of the dispenser, this distri-

  scorer being axially. mobile inside the body,

  means for varying the axial position of the device

tributor inside the body, and a transducer to emit a signal representative of the axial position of the

d: i stributor.

  The object of the invention is to provide an apparatus

  of the type considered in a simple and practical form.

  According to the invention, in an apparatus of the type considered

d, the transducer comprises a first series of marks on said part, a second series of marks on another element which can rotate with the distributor, a first and a second detector mounted in the body of the device, intended to emit electrical signals when passing the marks in front of the detectors, this other element being driven by the distributor by connecting means so that, when the distributor

  is moved axially inside the body, the depha-

  wise between the signals emitted by the two detectors varies, and an electrical circuit to measure this phase shift and

provide an indication of the axial position of the distri-

  scorer. The invention will now be described with reference to the accompanying drawings in which: FIG. 1 is a view in side elevation and in

section of an example of a device.

  Fig. 2 is a sectional view of part of the ap-

  the same in fig. 1, according to a different radial plane.

Figs. 3 and 4 are sectional views of the parts

  of the appliance shown in fig. 1 and 2.

  Fig. 5 is a sectional view of part of the apparatus

the same in fig. 1.

  Fig. 6 schematically represents the apparatus in

  showing an example of the transducer.

  Figs. 7 and 8 are side views in the di-

section of arrows B and A, respectively in fig. 6; and

  Fig. 9 is a block diagram of a control system.

The apparatus shown in fig. 1 comprises a body marked as a whole at 10, preferably formed from a generally bell-shaped part 11 which may be of light alloy and the open part of which

  is closed by a cover 12 made of steel. The body com-

  carries lugs 13, pierced, thanks to which the provision

  can be attached to the engine with which it is associated.

  A rotary drive shaft 14 is mounted in the body II and, in service, is coupled to an element of

control of the associated motor so that the drive shaft

It rotates in synchronism with the motor. The drive shaft 14 extends in the substantially cylindrical chamber 15 defined by the two parts of the body and has a wider bell-shaped part 14a

inside the room. This enlarged part pre-

  feels two diametrically opposed slots 16. The part

  of the drive shaft is hollow and the over-

  inner side of its end opposite the smaller diameter part of the shaft has the shape of a cylinder

straight and surrounds a boss 17 defined on the neck

  circle 12. The remainder of the inner surface of the enlarged part of the drive shaft is conical, for a purpose which will be described below. In addition, the drive shaft has a counterbore 18. An oil seal 19 is mounted on the outer end of the body 10 to cooperate with the drive shaft 14 and a plain bearing 20 supports the rotating shaft, the latter being further supported by the boss 17. A thrust surface prevents the shaft from moving axially and cooperates with the end surface defined between the two parts of the shaft. The pushing surface is defined

  by an annular plate 21 which surrounds the drive shaft

  and which also serves as a terminal closure for

  a low pressure fuel supply pump 22.

The rotor 22a of the feed pump is carried by the drive shaft 14 and it carries vanes which cooperate in turn with an eccentric surface on an annular stator 22b carried inside the part of the

  body 11. The low pressure pump has an inlet for

  burant 23 connected to a fuel supply in a

  frame fixed on the body part 11 and a car outlet

burant 24. In addition, a pressure relief valve 25 ensures that the outlet pressure of the pump remains inside

  desired limits, this valve being mounted between the

mission and repression.

A cylindrical bore 26 is formed in the cover.

  key 12 and a sleeve 27 is fixed in this bore. A distributor 28, angularly and axially movable, housed in the sleeve 27, projects into the chamber 15

  and has a larger head located in the chamber. An alé

  transverse sage 29 is formed in the distributor head

and two pump plungers 30 are housed in this bore.

The bore 29 communicates through a blind passage 31 formed

4 2476225

  in the dispenser, and closed by a plug at its end located inside the head. As can be seen more clearly in FIGS. 2, 3 and 4, the passage

  31 communicates with two diametral longitudinal slots -

  opposite 32 formed in the periphery of the dispenser

and communicating with passage 31 through

  re of one or more connecting passages. The passage

  31 also communicates with another longitudi-

nale 33 formed in the periphery of the distributor and

  this slot communicates in turn with several orifices

  these outlet 34 formed in the sleeve 27; as we

  see in fig. 2, the outlet ports 34 communicate

  quent respectively with outputs 35 in the cou-

  vircle 12. Each outlet contains a conventional type of discharge valve 36. The slots 32 face in turn the inlet orifices 37 formed in the sleeve 27 and communicating with a peripheral groove 38 formed in the periphery of the sleeve. Throat 38 communicates

  with the output 24 of the low pressure pump 22 by the

  through an open / closed valve 39 preferably controlled by an electromagnetic device 40. It is possible to envisage a single slot 32, with a number of orifices

  arrival equal to the number of exits.

An annular cam ring 41 surrounds the head of the device.

tributor 28 and pairs of diametrical cam lobes-

  opposites are formed on the peripheral surface

  inside of this cam ring. In this particular example

  link, three pairs of lobes are provided because the apparatus is designed to supply fuel to a six-cylinder engine. In addition, the cam ring 41 can be moved angularly around the axis of rotation of the distributor by means of a device

control by pressurized fluid, identified in its set -'-

  ble at 42, and connected to the cam ring by a radial stud 43. The device 42 preferably comprises a piston subject to a spring, housed inside a cylinder at one end of which a

lilqut.ide under pressure to act on the piston and push back

  act against the action of its jurisdiction.

Dl: lLx diverter's dl caames are arranged on the ends

  outer mites of the plungers, each comprising a roller 44 'carried in a shoe 45. Two lateral plates 46 and 47 retain the followers axially with respect to the distributor, these plates being fixed on the lateral faces of the distributor's head. Preferably, as seen in FIG. 5, the side plates 1O have an amnnular shape and comprise two tongues 48 extending outwards, which are arranged in the

slots 16 formed in the enlarged part of the drive shaft

  dragging. In fig. 5, we see the plate 46; these plates serve to transmit a rotational movement 13 to the distributor from the drive shaft. The pads 45 are also arranged inside the abovementioned slots lb, and the rotational movement is

  transmitted to the skates directly by the drive shaft

  is lying. In addition, the peripheral lateral faces of the

  skids conmporti: nt extensions 49 extending circum-

  preferentially, whose outer surfaces in the radial direction are inclined to cooperate with the conical surface formed by the inner surface of the part

  enlarged drive shaft 14.

In service, when fuel reaches the bore-

  ge 29> that is to say when a groove 32 faces an inlet passage 37, the plungers 30 are moved outward by the fuel pressure, and in so doing, impart a movement towards the outside the pads 45 and the rollers 44I. The outward movement is limited by the abutment of the inclined surfaces of the

  pads and on the conical surface of the tree, and moving

  axially cutting the distributor, the length is varied

of this displacement towards the outside. We can thus adjust the amount of fuel arriving at the bore 29, this in turn determining the amount of fuel supplied to an outlet when the plungers 30 are

  moved inward by a pair of cam lobes.

  The axial position of the valve can be changed

  mechanically or hydraulically linked. In the agency-

  shown, this variation is obtained by varying the pressure inside a defined chamber 50

  by the end of the bore 26 in the cover 12.

The end of the bore 26 is closed by a closure element and pressurized fuel is admitted into the chamber 50 via a small diameter orifice 51 carried by the sleeve 27. The orifice 51 communicates with outlet 24 of pump 22. Fuel

  can be evacuated from chamber 50 so that the pressure

Zion in this room can be adjusted, via

  diary of a valve 52 with electromagnetic control. In

  in addition, the distributor is subject to a compression spring

  helical pressure 53 which is housed inside

the blind bore 18 formed in the drive shaft 14.

The spring 53 acts between the drive shaft and the

distributor and repels the latter against the action of -

  fuel under pressure in chamber 50, which acts on

this distributor.

By varying the pressure in the chamber 50 using the valve 52, it is possible to vary the axial position of the distributor and, therefore, the amount of

fuel supplied whenever divers move

hundred inward.

  For a given axial position of the distributor and, neglecting leaks, the quantity of fuel supplied by the divers remains constant over the entire range of

  associated motor speeds and an indication of the posi-

  axial position of the distributor is provided by a trans-

  conductor. We will describe a form of transducer with reference

in fig. 6, 7 and 8. Two probes 54 and 55 detect respec-

  the passage of two series of marks when the shaft is rotating. Each time a marker passes a detector or probe, the latter emits a signal. The first series of marks 56 is formed on the part 14a of the drive shaft and each mark is constituted

by an axial groove.

  The second series of marks is formed by several axial ribs 57 formed on the peripheral surface

of a sleeve-shaped part 58 carried by the distri-

  scorer. The sleeve is applied by a compression spring.

  helical sion 59 in contact with a fixed stop 60 and an inclined groove and lug connection is provided between the distributor and the sleeve. In the present case, the distributor has an inclined groove 61 which cooperates

  with a lug 62 carried by the sleeve. When the dis-

  tributor is moved axially, the sleeve remains in its axial position in contact with the stop 60 and it rotates with the distributor, but the relative angular position of the sleeve and of the distributor varies due to the connection with helical groove and lug. The pulses emitted by the probes 54 and 55 have a phase shift which varies

with the axial displacement of the distributor. The transduc-

  tor is calibrated by adjusting the stop 60.

  As seen in fig. 9, the signals emitted by the detectors or probes 54, 55 are brought to a phase-shift measurement circuit 63 from which is obtained a signal representative of the axial position of the distributor and, in fact, a signal which represents the quantity of fuel delivered by the device to the associated motor. This signal

  is brought to a control circuit 64 which also receives

  a signal on its terminal 65, representing the fuel request signal; the output of circuit 64 sets the

valve position 52.

  A change in temperature can cause a

  the amount of fuel supplied by the appliance

  reil and a way to compensate for the temperature variation

  This consists in modifying the signal appearing at the output of circuit 63. This object is achieved by a phase delay circuit 67 which can, for example, receive a temperature signal produced as a result of the measurement of the resistance of the windings of the valves.

electromagnetic, for example.

  Another way of achieving temperature compensation is to insert between the circuit 63 and one of the detectors a phase shifting circuit 66 sensitive to the

  body temperature and causing a

  compensating phasing so that the signal obtained at the output of circuit 63 is a true indication of the quantity of fuel delivered by the appliance to the

associated motor.

  The term "benchmark" was used in the description

and in the example described, the marks are grooves or ribs. In this case, the detectors or probes

  are capacitive in nature. Of course, any-

  times, that all other forms of probes and markers can be used. For example, the markers can be magnetic in nature and the detectors or probes can be sensitive to the magnetic flux produced when

  the markers pass in front of these probes.

  It is preferable to choose the position of the distributor which gives the coincidence of the pulses so that it

  corresponds to a maximum of fuel. This allows

  define the maximum precision of the fact that variations in

  the speed of rotation will show the output signal

  tie of circuit 63 at positions other than those which

  give the coincidence of the impulses.

Claims (4)

CLAIMS i - Fuel injection pumping apparatus for internal combustion engine, comprising a body (10), a rotary distributor (28) mounted inside the body and arranged to be, in service, driven in synch- ronism with the engine with which the device is associated, a transverse bore (29) formed in the distributor, a plunger () 0) located in this bore, a cam follower (44, 45) disposed at the outer end of the plunger ] o to cooperate with a cam surface formed on a cam ring (41) surrounding the distributor (28), stop means (49) to limit the displacement of the plunger outwards, these stop means comprising surfaces inclined in a complementary manner respectively, on the follower and on a part (i4a), this part being able to rotate with the distributor, but being axially fixed inside the body, whereby, when the distributor (28 ) is moved axially inside the body (o0), the distance of which the plunger (30) can move outward when fuel is supplied to the bore varies, passage means (31, 32, 37, 34) for supplying fuel to the bore and for evacuate it during the rotation of the distributor, this distributor being axially movable inside the body, means (50) for varying the axial position of the distributor inside the body, and a transducer for emitting a signal representative of the axial position of the distributor, characterized in that the transducer comprises a first series of marks (36) on said part (] 4a), a second series of marks (57) on another element (58) which can rotate with the distributor (28), a first and a second detector (54, 55) mounted in the body of the apparatus, intended to emit electrical signals when passing the marks in front of the detectors, this other element (38) being driven by the distributor (28) by connecting means (61, 62) of such a type te that, when the distributor is moved axially inside the body, the phase shift between the signals emitted by the two detectors varies, and an electrical circuit to measure this phase shift and provide an indication of the axial position of the distributor. 2 Apparatus according to claim 1, wherein the connecting means comprise a lug connection (62) and a helical groove (61), the other element being in the form of a sleeve (58) surrounding the distributor (28).   3 - Apparatus according to claim 2, characterized   in that elastic means (59) recall the man-   chon (58) in contact with a stop (60) carried by the body.   4 - Apparatus according to one of claims 2 and 3,   wherein the helical groove (61) is formed in the distributor (28). - Apparatus according to one of claims 1 to 4, in which the electrical circuit includes a circuit phase shift measurement (63). 6 - Apparatus according to claim 5, comprising means (66 or 67) for correcting the signal produced   by this circuit (63) as a function of the temperature. 7 - Apparatus according to claim 6, wherein the temperature correction means comprise a phase delay circuit (67) interposed between this   circuit (63) and one of the detectors, this delay circuit dement phase receiving a varying control signal   depending on the temperature of the device.