FR2625263A1 - FUEL SUPPLY SYSTEM - Google Patents

Abstract

The fuel supply system is characterized in that a pressure accumulator 24 with an expansion chamber 25 is arranged between the lines 23, 4 connecting the fuel pump 1 and the hydraulic pump 11, that the inflow of fuel from the hydraulic pump 11 to the pressure accumulator 24 is controlled by a valve 26 which opens when the expansion chamber 25 of the pressure accumulator 24 is empty and which then remains open as long as the fuel supply lasts , and that the fuel returned via a forced pipe 7 is injected into a chamber 27 of the pressure accumulator 24 located between the valve 26 and the hydraulic pump 11 and respectively the pipe 23 opening into the working chamber 15 of said hydraulic pump 11. The fact of avoiding gas bubbles in the suction line 4 of the pump 1 makes it possible to obtain a reliable hot start and a good operation of the internal combustion engine, without r use of electric pumps.

Description

Fuel supply system The invention relates to a system

  fuel supply for internal combustion engines, with a fuel pump driven by the internal combustion engine and with a preliminary feed pump in the form of a hydraulic pump which is driven by the

  return fuel from the fuel pump.

  Fuel supply systems are born

  necessary for internal combustion engines mounted in

motor vehicles.

  DE-OS 2 804 550 discloses a system

  fuel supply system in which an excess quantity discharged by a fuel pump is sent to a jet pump placed in the tank as a preliminary feed pump, which offers the advantage that, given the pressure increased on the suction side of the

  fuel pump, gas bubbles should not occur.

  in the suction line.

  Mechanical fuel pumps are mounted on and driven by the internal combustion engine and generally have an excess amount not required by the internal combustion engine which can be compressed, which allows, compared to the fuel system, well-known power supply, a considerable increase in discharge energy for the preliminary fuel supply.

  The invention is based on the idea of using quantum

  surplus high pressure vessels returned for training

  preliminary feeding pumps in accordance with

  hydraulic pumps. With regard to hydraulic pumps

  In this case, it is possible to envisage the use of differential piston pumps whose smaller piston is loaded by the excess quantity under high pressure and whose larger piston forces a quantity of fuel to the fuel pump.

  sufficient preliminary feed which is, however,

  put in a pressure much smaller than the surplus quantity. Starting from the fuel supply system described above and the objective sought, namely to use excess quantities under high pressure of

  fuel pumps for preliminary feeding, the

  The purpose of the intervention is to create a new food system

fuel.

  According to the invention, this object is achieved by the fact that a pressure accumulator with expansion chamber is arranged between the pipes connecting the fuel pump and the hydraulic pump, the influx of fuel from the hydraulic pump to the pressure accumulator is controlled by

  a valve that opens when the relaxation chamber of the ac-

  The pressure accumulator is empty and remains open for as long as the fuel arrives, and the fuel returned via a penstock is injected into a chamber of the pressure accumulator.

  between the valve and the hydraulic pump and respectively

  conduct leading to the working chamber of the-

called hydraulic pump.

  Advantageous features are that

  the valve controlling the inflow of fuel from the heat pump

  hydraulic pressure to the pressure accumulator is controlled by a differential pressure regulator and a movable wall of the pressure accumulator, that a mouth section of a forced pipe provided for the return fuel is

  closed when the valve is open, that chambers

  on both sides of the differential pressure regulator

  are connected by a throttling line, and that parallel to the throttling

  discharge pipe controlled by a unidirectional

  nelle. According to another particular characteristic, the hydraulic pump is in the form of a differential piston pump and a stepped diaphragm pump respectively, the working stroke of which increases the volume of a discharge chamber while tending a spring of recall

  piston and respectively membrane.

  It is advantageous that the mobile wall of the accumula-

  pressure actuator acts on a leaf spring attached to the valve. Another advantageous feature is that

  that, in the absence of pressure in the pipe leading to a

  the valve or membrane is maintained by a

  pressure-sensitive, in a position in which

  the valve remains closed even when the pressure accumulator

  is completely or partially empty, and that in the suction line is inserted a control valve which, in the absence of pressure in the pipe leading to the mixer, interrupts the communication with the chamber situated downstream of the valve between the hydraulic pump and the pressure accumulator and at the same time establishes, via a return line, a connection between the pipe leading to the

  fuel pump discharge chamber and the fuel

  see. It is advantageous that the control valve is

  actuated by the additional diaphragm acting on the mem-

  brane and respectively on the valve or by a separate membrane

adorned.

  - In another embodiment, the control valve

  Mande is electromagnetically operated.

  According to a particular characteristic of the invention,

  it is intended that the pipe leading to the tank

  constituted by a return line of a control valve

  pressure placed in the line leading to the mixture

  of the internal combustion engine.

  According to another feature of the invention, a pipe section equipped with a unidirectional valve is inserted between the suction pipe and the return pipe.

  It is also advantageous that the additional membrane

  is connected to the first membrane through

  of a sliding connection system or that it acts

  on the piston tip of the valve.

  Finally, it is possible, in the context of this

  invention, to provide more than one hydraulic pump.

  The description that follows, next to the drawings

  appended by way of non-limiting examples, will allow to understand how the invention can be put into practice. FIG. 1 represents an exemplary embodiment with manual start, FIG. 2 represents an exemplary embodiment with

automatic start.

  Fig. 1 shows a mechanical fuel pump

  well known, mounted on an internal combustion engine 2 and

  dragged by it through a camshaft 3.

  The fuel pump 1 comprises a pipe 4 for

  suction and a pipe leading to a device

  In this latter case, the inflow into the forced pipe 7 can be controlled by a valve 8 which reacts with the position of the pipe. a pump piston 9, which makes it possible to regulate a determined flow rate

  as excess quantity.

  In a fuel tank 10 is integrated a

  hydraulic pump 11 serving as a preliminary feed pump

  nary. This hydraulic pump 11 comprises a different piston

  14 sealed by membranes 12, 13 and forming a

  a working chamber 15 of reduced diameter, a chamber of

  16 of larger diameter and a suction chamber

  17. The suction chamber 17 communicates via

  of a sleeve 18 acting as a unidirectional valve

  with the reservoir 10 and comprises a spring 19 which is mounted between the differential piston 14 and the housing 20 and tensioned during the increase of the volume of the discharge chamber 16. The working chamber 15, the discharge chamber 16 and the suction chamber 17 are interconnected by

  via unidirectional valves 21, 22 is

  in the direction of the working chamber 15. The working chamber 15 is connected, via a pipe 23, to a pressure accumulator 24 with an expansion chamber 25

  disposed outside the tank 10. The pipe 23 de-

  mouth, as the forced pipe 7, in a chamber 27 of the pressure accumulator 24 arranged upstream of a

valve 26.

  The valve 26 is connected to a membrane 28 acting as a differential pressure regulator and charged

  by a spring 29 in the closing direction of the valve 26.

  The membrane 28 seals a chamber 30 located downstream of the valve 26 relative to the expansion chamber 25 and comprises a throttle pipe 31 and a

  discharge pipe 33 controlled by a unidirectional valve

  32 which connect the two chambers 30, 25 together.

  A diaphragm disk 36 fixed to a membrane 35

  which ensures the sealing of the expansion chamber 25 by means of

  port to a room 34 communicating with the atmosphere includes

  two protrusions 37 which are applied, by the force of a res-

  fate 38 placed in the chamber 34 communicating with the atmosphere

  sphere, against a leaf spring 40 sandwiched between

  edges 39 of the housing and the valve 26 and cause a deformation

  elastic mation of said leaf spring so that

  the valve 26 connected to the latter is open.

  The pipe 4 of the fuel pump 1 provided for the suction opens into the chamber 27 of the accumulator of

pressure 24.

  The valve 26 is balanced by a discharge channel 41 and a piston tip 42 of the valve 26, the tip of

  plunger 42 closing off the mouth section of the

  7 when the valve 26 is open.

  The membrane 35 of the expansion chamber 25 comprises another diaphragm disk 43, an appendage 44 of which extends beyond

  through a casing opening 45, outwardly and com-

  carries a handle allowing the manual movement of the mem-

brane 35.

  Fig. 2 shows an alternative conformation of the system.

  Feeding system of FIG. 1 in which Appendix 44

  manually moved is replaced by an additional membrane

  50 which seals the chamber 34 communicates.

  the atmosphere with respect to an additional bedroom

  which is connected, through a derivative

  52, to the pipe 5 and in which the pressure is equal to that prevailing in said pipe 5. The membrane is loaded by a spring 53 in the direction of a decrease in the volume of the chamber 51 and connected to the membrane 35 In line 4 is inserted a control valve 55 which

  responds to the pressure in line 5 and interrupts the connection

  with room 30 by simultaneously

  nication with a pipe 56 which leads to the

  10. In this case, the connection is constituted by a return line 56 which starts from a pressure regulating valve 57 placed in the pipe 5. The driving section

  58 between the line 4 and the return line 56 com-

  takes a unidirectional valve 59 whose function is

described below.

Operation

  Before commissioning the combustion engine

  internal arrangement 2, the following fuel supply system

  see fig. 1 is filled with fuel via the handle 46 of the diaphragm disc 43, that is to say that the expansion chamber 25 of the pressure accumulator 24 is,

  also filled with fuel, but it is also pos-

  to take other aeration measures as will be

  again indicated later with reference to FIG. 2.

  When starting the internal combustion engine 2, the fuel pump 1 is driven by the camshaft 3

  and draws into line 4 subjected to the pressure of

  pressure emitter 24, fuel flowing from the chamber

  of relaxation 25, through the conduct of foreign

  , glement 31 and the discharge pipe 33, under pressure

  created by the membrane 35 and the tensioned spring 38.

  During the discharge stroke, the fuel is sent from the fuel pump 1 filled to the device

  mixer 6, and the internal combustion engine 2 starts.

  By its construction, the fuel pump 1 is designed for a much higher flow rate than that required for the operation of the engine, which results in each delivery stroke the flow of an excess quantity which, by

  through the penstock 7, arrives in the accumu-

  pressure 24 upstream of the valve 26 then closed,

  and is injected into the working chamber 15 of the heat pump

  hydraulic 11 through the conduit 23 which also opens in this area. The return is made at least at the same pressure as that provided for the device

  mixer, for example under 3 to 4 bar.

  The differential piston 14 solicited by this quantity

  excess pressure is moved, with each new inflow, until the discharge chamber 16 which

  grow then has reached its maximum volume and that the

  19 is located inside the suction chamber 17 was at the same time stretched to the maximum. The discharge chamber

  growing collects, through the universal valve

  directional 21, the fuel from the suction chamber 17 as the volume of the chamber

suction 17 decreases.

  As soon as the chamber of relaxation 25 of the accumulator of

  pressure 24 is empty, the two protrusions 37 of the disk of

  Fig. 36 push the leaf spring 40 into a position

  causing the valve 26 to open, resulting in the ob-

  turation of the mouth section of the penstock 7

  by the end of the piston 42. The pusher of the fuel pump

  tible 1 then acts on a coupling spring, which

  void the interruption of the push-back.

  The opening of the valve 26 causes a pressure drop in the working chamber 15 of the hydraulic pump 11, which has the effect that the tensioned spring 19 displaces the

  differential piston 14 in the direction of a reduction of chambers

  discharge and working members 16, 15.

  As a result, the fuel contained in the chambers

  pressure and work 16, 15 is pushed through

  of the unidirectional valve 22 and respectively of the pipe 23, in the chamber 27 situated between the valve 26

  and the diaphragm 28 acting as a different pressure regulator

  the effect that, on the one hand, the membrane 28 occupies a position in which the valve 26 remains open

  and that, on the other hand, the fuel is injected

  the throttle line 31 in the expansion chamber 25 until it is filled or no

  fuel no longer arrives from the hydraulic pump 11 of

  in that the membrane 28 takes a position in which the valve 26 is closed again. During the delivery of the hydraulic pump 11, the

  suction chamber 17 has been enlarged and sucked

  tible in the tank 10. The return of the excess quantity which starts again now that the tip of the

  piston 42 connected to the valve 26 has cleared the sealing section

  of the forced pipe 7 following the closure of the valve 26, causes a new fuel suction

in the delivery chamber 16.

  The fuel supply system shown in FIG. 2 differs from that described above in that the aeration is done automatically, that is to say it is

  possible to give up the handle of the diaphragm disc.

  All other functions are identical to those described in FIG. 1. Before the first start-up or after draining the system, the differential piston 14 of the hydraulic pump 11 is in the opposite position to that shown in FIG. 1, that is to say that the chamber

  17 contains fuel, the refueling chamber

  16 presents its minimum volume and is possibly

filled with air.

  Since the pressure inside the

  pipe 5 does not exceed the barometric pressure, the

  brane 50 is applied, under the action of spring 53, against

  wall of the pressure accumulator 24. The membrane 35

  sliding system is then maintained in a position in which the valve 26 remains closed, even when the pressure accumulator is entirely or

partially emptied.

  The control valve 55 interposed in the pipe 4 and constituted, for example, by a hydraulic valve or by a solenoid valve, has interrupted, in accordance with the low pressure inside the pipe 5, the connection between the

  chamber 30 and the fuel pump 1 (and possibly

  bli a connection with the return line 56).

  When starting the internal combustion engine

  the fuel pump 1 is driven by the camshaft 3 and sucks, through the pipe section 58, the unidirectional valve 59 and the

  return line 56, fuel contained in the fuel tank

  see, which fuel reaches the mixing device and, via the pipe 7, shown here as bypass of the forced pipe 5, to the chamber 27 and, via the pipe 23, to the chamber of

  work 15 of the hydraulic pump 11.

  The differential piston 14 solicited by this quantity

  increased the volume of the refueling chamber

  which is then filled with the contained fuel

  in the suction chamber. 17. As soon as the pressure inside the

  5 is mounted, the membrane 50 is pushed against the force of the spring 53, in a position in which the movement of the diaphragm 35 is no longer influenced by the sliding connection system 54, and the control valve

  establishes the connection between the sections of the pipe 4.

  Because the pressure accumulator 24 is empty, the diaphragm 35 causes the valve 26 to open, the piston tip 42 closing the mouth section of the pipe

  forced 7 when the valve 26 is open.

  As has been described with reference to FIG. 2

  the opening of the valve 26 causes the injection of the fuel

  tible contained in the discharge and working chambers 16, 15, through the unidirectional valve 22 and respectively of the pipe 23, in the chamber 27 located

  between the valve 26 and the membrane 28 acting as a regulator

  differential pressure, which has the effect that, on the one hand, the membrane 28 is brought into a position in which the valve 26 remains open and that, on the other hand, fuel is injected, via the throttle line 31, in the expansion chamber 25 until it is filled or no fuel no longer flushes the hydraulic pump 11 with the result that the

  that the membrane 28 occupies a position in which the

  Pope 26 is closed again. The one-way valve 59 inserted into the line section 58 ensures that the upper pressure in the line 4 when the hydraulic pump is discharged does not pass into the return line 56. Actuation of the control valve 55 can take place by the membrane 50 or by a separate membrane or electromagnetically. The membrane 50 can also act directly on the valve 26, that is to say on the tip

piston 42.

  According to the choice of the ratio of action of the surfaces of the

  differential piston 14 and the spring force 19, the

  pleating of the relaxation chamber 25 of the accumulator of

  pressure 24 is under predetermined pressure and above

  above the barometric pressure.

  Avoiding gas bubbles in the suction line of the pump allowed to obtain the benefits well

  known such as a reliable hot start and a functioning

  without disturbing the internal combustion engine, the

  this is done without the use of electric pumps which are costly to install and cause disturbances

and noise emissions.

  For complicated fuel tanks, it is

  It is also possible to use several hydraulic pumps.

he

Claims (14)

  1. - Fuel supply system for   internal combustion engines, with a fuel   dragged by the internal combustion engine and with a preliminary feed pump in the form of a hydraulic pump which is driven by the return fuel from the fuel pump, characterizes a pressure accumulator (24) with expansion chamber (25) is arranged between the pipes (23, 4) connecting the fuel pump (1) and the hydraulic pump (11), that the influx of fuel from the hydraulic pump (11) to the pressure accumulator (24) is controlled by a valve   (26) which opens when the relaxation chamber (25) of the   pressure accumulator (24) is empty and then remains open for as long as the fuel arrives, and that the fuel returned via a forced pipe (7) is injected into a chamber (27) of the 'accumulator   pressure valve (24) between the valve (26) and the heat pump   hydraulics (11) and respectively the pipe (23).   2. - Fuel supply system according to   Claim 1, characterized in that the valve (.26) controls   the influx of fuel from the hydraulic pump (11) to   the pressure accumulator (24) is controlled by a regula-   differential pressure transmitter (28) and a movable wall   (35) of the pressure accumulator (24).   3. - Fuel supply system according to   one or more of claims 1 or 2, characterized in that   a forced pipe (7) intended for the return fuel is closed when the valve (26) is opened.   4. - Fuel supply system according to   one of claims 2 or 3, characterized in that   chambers (30, 25) formed on either side of the differential pressure regulator (28) are connected by a pipe throttling (31).   5. - Fuel supply system according to   claim 4, characterized in that it comprises, parallel-   the throttle line (31), a driving line   load (33) controlled by a one-way valve (32).   6. - Fuel supply system according to   one of claims 1 to 5, characterized in that the pump   (11) is constructed as a pumping pump.   your differential and respectively stepped membrane (14) of which   the working stroke increases the volume of a chamber of   (16) while straining a piston return spring and respectively of membrane (19).   7. - fuel supply system according to claim 2, characterized in that the movable wall (35) of the pressure accumulator (24) acts on a leaf spring (40) attached to the valve (26).   8. - Fuel supply system according to   one of claims 1 to 7, characterized in that, in   the absence of pressure in the pipe (5) leading to a mixture   (6), the valve (26) or membrane (35) is held by a pressure sensitive member (50) in a position   valve (26) remains closed even when the   pressure accumulator (24) is completely or partially empty, and that in the suction line (4) is inserted a control valve (55) which, in the absence of pressure in the line (5) leading to the mixer, interrupts communication   with the chamber (30) located downstream of the valve (26) and   at the same time, through a   turn (56), a connection between the pipe (4) leading to the chamber   flow of the fuel pump (1) and the see (10).   9. - fuel supply system according to claim 8, characterized in that the control valve   (55) is actuated by the additional diaphragm (50) acting   on the diaphragm (35) and on the valve (26) or by a separate membrane.   10. Fuel supply system according to claim 8, characterized in that the control valve   (55) is electromagnetically operated.   11. - Fuel supply system according to   one of claims 8, 9 or 10, characterized in that the   pipe (56) leading to the tank (10) is constituted by a return line of a pressure regulating valve (57) placed in the pipe (5) leading to the motor mixer internal combustion.   Fuel supply system according to claim 11, characterized in that a pipe section (58) equipped with a unidirectional valve (59) is inserted between the suction pipe (4) and the fuel line. back (56). 13. - Fuel supply system according to   claim 8 and respectively one of the claims 9   at 12, characterized in that the membrane (50) is connected to the   membrane (35) via a connection system   smoothing (54) or acting on the piston tip (42) of the valve (26).   14. - Fuel supply system according to   one of claims 1 to 13, characterized in that it pre-   sees the implementation of more than one hydraulic pump (11).