FR2484546A1 - PRESSURE REGULATOR FOR INJECTION SYSTEM OF INTERNAL COMBUSTION ENGINE WITH CONTROLLED IGNITION - Google Patents

Abstract

THE OBJECT OF THE PRESSURE REGULATOR OF THIS INVENTION FOR AN INJECTION SYSTEM IS TO CONTROL THE FUEL PRESSURE OF THE INJECTORS BY CONSTANTLY COMPARING IT TO A GIVEN VALUE, IN ORDER TO MAINTAIN A CORRECT AIRCARBON REPORT WHAT THE CONDITIONS ARE OF ENGINE OPERATION. IN GENERAL, IT CONSISTS OF AN ARRANGEMENT OF VARIOUS MECHANICAL COMPONENTS WHICH ACT TO DIVIDE THE FUEL CURRENT PROVIDED (THROUGH LINE 11) BY A PUMP IN TWO UNIQUE PARTS. ONE OF THE PARTS OF THIS CURRENT IS TRANSMITTED TO THE INJECTORS (BY LINE 12), WHICH ABSORB THE QUANTITY NECESSARY UNDER THE OPERATING CONDITIONS OF THE ENGINE. THE REMAINDER IS RETURNED TO THE TANK OF THE VEHICLE (BY LINE 15).

Description

No 1 The present invention relates to regulators of

fuel pressure and, more particularly, a regulation

  tor comprising the functional elements which constitute the subject of Italian patent application No. 3325 A / 78 of February 7, 1978. The characterizing part of the regulator described in this patent application is the use of a valve element consisting of a hemisphere, the center of which is located in the plane surface limiting it and which controls entry

  to a return line to the tank. This element of cla-

  pet is stressed by elastic forces so as to remain

  in contact with the walls of a cavity formed in a sup-

  integral with the diaphragm, so that the movements of the plane of the valve element are equal to the movements of the

support.

  This pressure regulator offers configura-

  that are new in patentability, original and technically valid. However, it raises certain construction and mounting problems which are

  difficult to solve in the case of mass production.

The object of the present invention is to avoid the above problems by means of a valve element which functionally does not depart from the proposed solution

in said patent application, but which is more apt to

  2. solve the construction and assembly problems raised

by mass production.

  The present invention will be well understood during

the following description made in relation to the drawings

  attached in which Figure 1 is a view, partly in section, of a

regulator according to the present invention according to a plan

nant the axis of symmetry of the device; and FIG. 2 is a view, partly in section, of the valve element constituting a regulator part of

Figure 1.

The regulator shown in Figure 1 consists of a metal casing 1 internally divided by a

  membrane 2 in two chambers 3 and 4 which do not communicate.

  Room 3 is defined by a housing 30 in

  more than membrane 2. Chamber 4 is defined by a housing

ment 40 in addition to the membrane 2.

The edges 31 and 41 of the two housings 3 and 4 sup-

  carry the membrane 2, and are fixed together by a ring 9, the parts 90 and 92 of which rest respectively on

  frustoconical parts 32 and 45 of the edges 31 and 41.

  Room 3 is connected to an intake manifold

sion (not shown) by a first pipe (not shown

  which is mounted on a tube 10. Thus, the reference pressure of the intake manifold is established

in room 3.

Chamber 4 is connected to an intake pump

in fuel through a second line (not shown)

tée on a tube 11, to the injectors of the injection system by a third line (not shown) mounted on a

tube 12, and on the other hand to the fuel tank of the vehicle

runs through a fourth pipe (not shown) mounted on

a connecting tube 5.

If convenient or appropriate, the connection fittings

mission 11 and 12 can be replaced by a single fitting 11. The connecting tube 5 comprises a part 50 which is 3. inserted into a through bore 44 made in the lower part of the housing 40. At the top of the bore 44, and on the same axis, there is a seat 46, of polygonal shape

  when viewed in plan, which contains the hexagon head

the tube 5 so as to avoid rotation. A frustoconical surface 43 connects the bore 44 to the seat 46. A surface

frustoconical-52 which constitutes a part of the tube 5 is there as-

  located. This coupling achieves a good fuel seal of the chamber 4, this seal being improved by the tightening effect of a nut placed on the threaded part.

53 of tube 5.

  The tube 5 also includes a cy-

  lindrique 54 in which an element 6 comprising the valve seat is inserted by force. A flat valve seat 61 and a flat surface 62 defined by a circular crown

  constitute the most important parts of element 6.

  The element 6 supported by the tube 5 constitutes the outlet nozzle and extends into the second chamber 4. The flat seat 61 receives the flat surface of the valve element 7. A spring 63 is disposed between the circular peripheral surface 62 and a similar surface 73 of the valve element 7. The spring-63 holds the spherical part of the valve element

  valve 7 in contact with the conical surface 81 of a comparison

  timent 80 provided in a support 8, which is integral with the

  membrane 2 by means of a cap 20.

  The lower end of a control spring

21 acts on the cap 20, its other end being supported

  ted by a hat 22; The latter includes a central bore

tral 23 which encloses the conical point 14 of a hexagonal head screw 13 inserted in a threaded bore which passes through a projection 33 of the upper part of the housing 30. By adjusting the screw 13, the spring 21 can be preloaded to a given value. The threaded bore flares upwards to become the cylindrical compartment 34 containing an expansion cap 15 which avoids the adjustment of the screw 13 by a

unauthorized person.

  4. Figure 2 shows in detail the element of

  valve 7 placed in compartment 80 of FIG. 1.

  The valve element consists of a spherical part 72 which is in contact with the frustoconical part 81 of the compartment 80 so as to constitute a ball joint, of which a flat surface 75 is opposite the flat seat 61 defining the excess fuel outlet section, a flat surface 73 in the form of a circular crown on which the upper end of the spring 63 rests, a cylindrical surface 74 connecting the surfaces 73 and 75 and on

which supports a few turns of the spring 63 during a sta-

preceding the mounting of the regulator, a blind hole 76

  perpendicular to the flat surface 75, and of a cylindrical rod

that 70 which extends over a flat surface 71 located

  154 in the part of the element 7 opposite the surface 75.

  Element 7 has an axis of symmetry A-A which coincides with the axes

  of symmetry of the hole 76 and of the rod 70. The center C of the sec-

  spherical tor 72 is located either in plane 75 or in

  a plane parallel to plane 75 but moved down.

Although not directly the subject of the

present invention, the operation of a pressure regulator

sion will be described briefly, so as to show the importance of the position of the center of rotation C of the valve member

7 in plan 75.

, During engine operation, the difference

  ce enters the pressure in the injector supply line

fuel counter connected to the control chamber 4 by the tu-

be 12 and the pressure in the intake manifold in the-

which are arranged the injectors must remain constant for all operating conditions of the engine. For this purpose, the regulator varies the defined delivery surface

between the surface 75 and the seat 61 of the nozzle 6.

Suppose that the pressure in the manifold increases

  lie; so as to keep this pressure difference constant, the flat surface 75 approaches the nozzle 61 under

  the effect of the thrust due to the increased pressure acting

sant on the side of the membrane 2 opposite the chamber 3, 5. in which prevails the pressure of the manifold as it has

already indicated. The resulting reduction in surface area

this back to the tank increases the pressure

  sion in chamber 4 to a practically identical value

  to that of the pressure in chamber 3, which has the effect of maintaining a constant pressure difference

between the injectors supply and the intake manifold

if we.

If the pressure in the manifold decreases, the regulator

  lator then makes the necessary adjustment of the injector supply pressure by moving the surface 75 away from

  the nozzle 61 by a similar mechanism.

Compared to the description given in the request

of Patent No. 3325 A / '78 cited above, the present confi-

  guration allows easier construction, as will be illustrated below, and an increase in the self-stabilization characteristics of the valve element 7 since it is now possible to move the center of application of the resultant closing forces acting on the valve member further below the control plane defined by the

surface 75, and to move the resulting open forces

ture exerted by the spring 63 resting on the crown of

the valve member 7 plus above the plane 75.

The present invention solves the particular problems

manufacturing and assembly lines.

The valve member 7 can be manufactured by factory

  age in automatic machines of a cylindrical bar

  made of suitable material. There are various manufacturing methods

  serial cation of element 7. Two of these methods will

described to show the simplicity of execution.

  The first method is to use a forming tool on an automatic lathe. Profile of this tool

corresponds to that of element 7, excluding the

  age 76, when the bar rotates around the axis of revolution

  A-A. The bore 76 is formed by means of a drill bit

ge.

  The second method is to use a pro lathe

6.

grammage which carries out a transverse advance so as to

finish item 7 completely.

  In order to better understand the function of the rod which physically defines the axis of symmetry of the part 5.7, it should be noted that the roughness of the surface 75 must be very low, in order to obtain correct operation of the regulator. To obtain a surface with very low roughness, a polishing operation must be performed on

  surface 75 after definition of element 7. This operation

tion can be executed on many elements which are

  held in a clamping device.

This clamping device consists of a metal plate in which many holes have been made, each hole being able to receive the rod 70 of the element 7, so as to maintain its axis of symmetry perpendicular to the plane of the plate. Consequently, the plane 75 is parallel to the plane of the plate and directed outwards, while the

  plan 71 abuts the surface of the plate.

  The parts 7 being mounted on this plate by inserting the rods 70 into the respective holes, a tool

polishing is passed on all surfaces 75 which are

  wind then rigidly positioned in a well defined plane.

  The shape of the valve element 7 shown in fig-

  re 2 makes it possible to assemble regulator 1 by means of

  automatic chines. This is due to the fact that the bore 76 allows the support of the part 7 by means of a device

  automatic suitable during one of the stages of the assembly

  ge. This device maintains it in a position coaxial with the housing 40, which makes it possible to immediately find the same axis between the housing 40 and the support element 8, the frustoconical cavity 81 of which is supported by the spherical surface 72 of the element 7 The membrane 2 is then correctly positioned relative to the edge 41 of the housing.

40.

  The following operations involving the mounting and adjustment of the spring 21, and the assembly and fixing of the

  housing 30 with ring 9 can be immediately executed

7.

particularly simple.

  The present invention is not limited to the examples

ples of realization which have just been described, it is on the contrary susceptible of variants and modifications which 'will appear to the person skilled in the art. 8.

Claims (4)

1 - Pressure regulator for injection systems   tion of an internal combustion engine with controlled ignition, comprising a metal casing, a membrane placed in the casing so as to divide its interior into a   first and second chambers, a first pipe re-   linked to the casing so as to connect the first chamber to the intake manifold, second pipes connected to the casing so as to connect the second chamber to a fuel supply pump and to the injectors, a fourth   pipe connected to the casing at the height of the return nozzle   tower, which extends into the second chamber so that it   ci is connected to the fuel tank, and is provided with a flat seat on which acts a control and stop means   of the flow of fuel returning to the tank, this means of stop and stop comprising a valve element defined by a spherical part and a flat surface, this element valve comprising a defined axis of symmetry and a compartment   housing provided in a support integral with the mem-   brane, the valve element being free to rotate in this compartment so as to keep its flat part facing the flat seat of the nozzle, characterized in that the element valve includes a blind hole that extends toward its interior   laughing from the flat surface, and a cylindrical rod extending outward from the side opposite the flat surface, the axes of symmetry of the bore and the rod coinciding with each other and with the axis of symmetry of the valve element, an elastic means being provided so as to urge the spherical part of the valve element to bring it into contact with the walls of the compartment, and the flat surface being defined either by a diametral plane of the spherical surface, either by a plane parallel to the line metric and moved slightly towards the cylindrical rod. 2 - Pressure regulator according to claim 1, characterized in that the valve element comprises a part   cylindrical tie and a flat surface in the form of a circular crown, the cylindrical part being arranged   so as to support a few turns of a spring, the end of which 9.   upper part rests on the surface of the circulating crown re, the. base of the cylindrical part being constituted by the flat surface which collaborates with the flat seat of the check valve   so as to control the flow of fuel returning to the tank see.   3 - Pressure regulator according to the claims 1 and 2, characterized in that the surface (73) on which the spring (63) rests downwards limits a spherical sector (72) and is located in a plane parallel to the diametral plane and moved towards the rod from the plane containing the center of the spherical surface. 4 - Pressure regulator according to the claims   1, 2 and 3, characterized in that the spring urging the element valve to bring it into contact with the walls of the compartment is supported at its lower end by a surface in the form of a flat circular crown constituting a part of the return nozzle member.   - Pressure regulator according to claim 1, characterized in that the valve element comprises a   second flat surface parallel to the flat control surface   from and to stop, this second flat surface being overcome by the cylindrical rod.