JPS642830B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel pressure regulator for a fuel injection system of a controlled ignition internal combustion engine, in particular the subject matter of Italian patent application No. 3325A/78 filed February 7, 1978. It relates to a pressure regulator including functional elements of a pressure regulator.

The purpose of a fuel injector pressure regulator is to constantly adjust the fuel supply pressure to the injectors by comparing it to a set point in order to maintain an accurate air/fuel mixture ratio under all internal combustion engine operating conditions. It's about adjusting.

In general, a pressure regulator consists of an arrangement of various mechanical elements that serve to divide the flow of fuel from a pump into two parts, one of which meets the requirements of the internal combustion engine's operating conditions. The other flow is returned to the fuel tank.

A feature of the pressure regulator according to the above-mentioned Italian patent application is the use of a hemispherical valve element (hereinafter abbreviated as valve body), the center of which forms the boundary plane of the hemisphere, and the return flow to the tank. This means that it is on the plane that forms the surface that controls the pipe inlet.

This valve body is held down by elastic means so that it is always in contact with the wall surface of the valve body storage chamber in the support body fixed to the diaphragm. is the same as

While this pressure regulator provides a new, original and technically effective design, it presents difficult structural and assembly problems that must be resolved in mass production.

The aim of the invention is to solve the structural and assembly problems in mass production by means of a valve element which is functionally the same as that of the said patent application, but which is suitable for mass production.

The main contents of the present invention are shown in FIGS.
This is a pressure regulator characterized by the items described in Section 1.

The pressure regulator shown in FIG. 1 consists of a metal case 1 which is internally divided into two chambers 3 and 4 which are not communicated with each other by a diaphragm.

Chamber 3 is delimited by diaphragm 2 and housing 30, and chamber 4 is delimited by diaphragm 2 and housing 40.

The edges 31, 41 of the two housings 30, 40 hold the diaphragm 2 and are clamped together by a ring 9, whose surfaces 90, 92 respectively
1 and 41 are in contact with the conical truncated body portions 32 and 45.

The chamber 3 is connected to the fuel intake manifold by a first pipe (not shown in the drawings) which is to be attached to the connecting pipe 10. The pressure of the suction manifold is thus set in chamber 3.

The chamber 4 is connected to the fuel supply pump by a second pipe (not shown in the drawings) to be attached to the connecting pipe 11 and a third pipe (not shown in the figures) to be attached to the connecting pipe 12. ) to the injector of the injection device and to the fuel tank by a fourth pipe (not shown in the drawings) which is to be further connected to the connecting pipe 5.
In some cases, the number of connecting pipes 11, 12 can also be reduced to a single connecting pipe 11.

The connecting pipe 5 has an insertion part 50 inserted therein through the through hole 44 in the lower part of the housing 40 .

A seat 46 is located at the upper end of the through hole 44 and coaxially therewith.
The seat 46 has a polygonal shape when viewed from above, and holds the hexagonal head of the connecting pipe 5 to prevent rotation.

The surface 43 of the truncated cone is the upper end of the through hole 44 and the seat 4
6, and the face 52 of the conical frustum of the tube 5 is in contact with the face 43.

This connection effectively seals the chamber 4 from the outside, and the tightness of the nut fitted into the threaded portion 53 of the tube 5 strengthens the seal.

The tube 5 has a cylindrical chamber 54 in which the valve seat component 6 is firmly inserted.

The plane valve seat 61 and the circular edge plane 62 are the most important parts of the valve seat component 6.

The valve seat component 6 is supported by the tube 5 and constitutes a reflux nozzle extending into the second chamber 4 .

The planar valve seat 61 is controlled by the planar portion 75 of the valve body 7 . A spring 63 is arranged between the circular edge plane 62 of the valve seat arrangement 6 and a similar plane 73 of the valve body 7.

A spring 63 maintains contact between the spherical surface of the valve body 7 and the frustoconical portion 81 of the valve body receiving chamber 80 in the support 8 which is fixed to the diaphragm 2 by the cap 20 .

The lower end of the control spring 21 acts on the cap 20.
The upper end of the spring 21 is supported by a spring support cap 22.

The cap 22 has a central hole 23 which receives the conical portion 14 of the hexagon socket head screw 13, which screw 13 is screwed into a threaded hole 33 passing through a projection 34 at the top of the housing 30. It is.

By adjusting the screw 13, the spring 21 can be preloaded to a constant value. The threaded hole 33 widens at the top and the telescopic cap 15
A cylindrical chamber 35 is formed. This cap 15 prevents adjustment of the screw 13 by an outsider.

The valve body 7 has a spherical part 72 which contacts the conical frustum part 81 of the chamber 80 forming a ball-and-socket joint.
, a flat part 75 that faces the flat valve seat 61 and determines the excess fuel outflow cross section, a flat part 73 with a circular edge that receives the upper end of the spring 63, and a cylindrical part 74 connecting the surfaces 73 and 75 (on which the spring is attached). 63 (the upper end portion of which is attached before assembly is completed), a blind hole 76 provided perpendicularly to a plane 75, and a cylindrical part 70 extending above the plane part 71 on the opposite side of the plane 75.

The valve body 7 has an axis of symmetry AA that coincides with the axis of symmetry between the blind hole 76 and the cylindrical portion 70 .

The center C of the spherical section 72 is placed either on the plane section 75 or on a plane parallel to the plane section 75 and moved downward.

Although not directly related here, the operation of the pressure regulator will be briefly described in order to demonstrate the importance of setting the rotation center C of the valve body 7 on the plane portion 75.

During operation of the internal combustion engine, the difference between the pressure in the injector fuel supply line, which is connected to the control chamber 4 by pipe 12, and the pressure in the intake manifold in which the injector is mounted, causes all of the internal combustion engine's It must also remain constant during operating conditions.

In order to obtain this state, the pressure regulator
5 and the valve seat 61 of the nozzle 6 is changed.

As mentioned above, the pressure inside the manifold pipe is set in the chamber 3, so if the manifold pressure increases, the thrust caused by the increased pressure acting on the side of the chamber 3 of the diaphragm 2 causes the flat part 75 to close the valve of the nozzle 6. The seat 61 is approached, so that the return cross-section to the fuel tank is reduced and the pressure in the chamber 4 is increased. This increase practically corresponds to the pressure increase in chamber 3. Thus, the pressure difference between the supply pipe to the injector and the suction manifold remains constant.

When the manifold pressure decreases, a similar mechanism pulls the flat section 75 away from the valve seat 61 of the nozzle 6.
The pressure regulator makes the necessary adjustments to the injector supply pressure.

The pressure regulator according to the present invention is easier to assemble than the pressure regulator according to Italian Patent Application No. 3325A/78, as will be described later.
The spring 6 moves the center of action of the closing force applied to the valve body 7 further below the flat portion 75, that is, the closing/adjusting surface, and is received by the circular edge 73 of the valve body 7.
Since the center of action of the opening force caused by 3 can be moved further above the flat portion 75, the self-stability of the valve body 7 is increased.

The present invention solves production or assembly problems.

The valve body 7 can be manufactured from a round bar of a suitable material using an automatic machine tool. There are various methods for mass-producing the valve body 7, but two methods will be explained for ease of implementation.

The first method is the use of automatic lathe forming tools.

The blade shape of this tool, excluding the blind hole 76, corresponds to the outer shape of the valve body 7, and the round material bar is cut by rotating around the rotation axis AA to form the valve body 7.

Blind hole 76 is formed by drilling.

The second method is to form the entire valve body 7 by program-controlled machining with vertical and horizontal movement.

The cylindrical portion 70 of the valve body 7 physically determines the axis of symmetry of the valve body 7 . To understand the purpose of this cylindrical section 70, consideration must be given to the fact that the surface roughness of the flat section 75 must be kept very low for correct operation of the pressure regulator.

After forming the valve body 7, lap finishing is necessary to obtain a very low surface roughness of the flat portion 75.

Lapping can be done on as many items as possible that can be attached to one fixture. This fixture consists of a metal plate with numerous holes;
Each hole can accommodate a cylindrical portion 70 of the valve body 7 such that its axis of symmetry is perpendicular to the metal plate. Therefore, the flat portion 75 of the valve body 7 is parallel to the mounting plate and faces outward, and the surface 71 is in close contact with the mounting plate.

The cylindrical portions 70 of the valve body 7 are inserted into the respective holes of the mounting plate, and after all the flat portions 75 are fixed, a wrap is placed on the surface.

By making the shape of the valve body 7 as shown in FIG. 2, it becomes possible to assemble the pressure regulator by an automatic machine. This is because, during the assembly phase, the blind holes 76 allow for attachment to suitable automatic machine fittings.

This automatic machine fitting directly makes it possible to keep the valve body 7 coaxial with the housing 40 and to make the housing 40 and the support 8 coaxial. The truncated conical portion 81 of the support body 8 is in contact with the spherical portion 72 of the valve body 7 .

The diaphragm 2 is thus precisely positioned relative to the edge 41 of the housing 40.

Next, the spring 21 is installed and the housing 30 is assembled.
Attachment and tightening with the ring 9 can be easily and directly performed.

The above description shows one embodiment of the invention, and structural changes may be made within the scope of the invention.

The geometry and materials used do not limit the scope of the invention.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a half-cut vertical sectional view taken along a plane containing the symmetry axis of the pressure regulator, and FIG. It is an enlarged half-cut vertical cross-sectional view. 1... Metal case, 2... Diaphragm, 3... First chamber, 4...
Second chamber, 6... Valve seat component or reflux nozzle, 7
... Valve body, 8... Support body, 61... Planar valve seat, 62... Circular edge plane, 63... Spring, 70... Cylindrical part, 71... Second plane part of valve body, 72... Spherical surface part, 73... Valve body circular Edge plane, 74... Valve body cylindrical part, 75... Valve body plane part,
76...Blind hole, 80...Valve body storage chamber.

Claims (1)

[Claims] 1. A metal case 1, and a first
a diaphragm 2 arranged therein to divide it into a chamber 3 and a second chamber 4; a first pipe attached to the case 1 for communicating the first chamber 3 to the suction manifold;
a second pipe attached to the case 1 for communicating the second chamber 4 with the fuel pump and the injector; and a fourth pipe attached to the case 1 at the reflux nozzle 6 extending into the second chamber 4. and is further provided with a planar valve seat 61 on which the means for closing and regulating the fuel return to the fuel tank act.
The adjusting means consists of a valve body 7 formed by a spherical part 72 and a flat part 75, the valve body 7 having a predetermined axis of symmetry and a storage chamber 8 in a support 8 fixed to the diaphragm 2.
0, and the valve body 7 is rotatable in the storage chamber 80 so that its plane part can always face the plane valve seat 61 of the nozzle, and the valve body 7 is rotated inwardly from its plane part 75. It has an extending blind hole 76 and a cylindrical part 70 extending outward from the opposite side of the flat part 75, and the axes of symmetry of the blind hole 76 and the cylindrical part 70 coincide with each other and the symmetry axis of the valve body 7. Accordingly, elastic means are provided to bring the spherical part of the valve body 7 into contact with the wall of the storage chamber 80, and the flat part 75 extends toward the cylindrical part 70 on the diametrical surface of the spherical part or on a surface parallel to the diametrical surface. 1. A pressure regulator for an injection device of a controlled ignition internal combustion engine, characterized in that it is formed by a surface that is slightly moved to the bottom. 2 The valve body 7 has a cylindrical portion 74 and a circular edge-shaped flat surface 73.
The cylindrical portion 74 is arranged to support a portion of the spring 63, the upper end of the spring 63 is received in the circular edge plane 73, and the base of the cylindrical portion 74, together with the planar valve seat 61, is arranged to support a portion of the spring 63. The pressure regulator according to claim 1, characterized in that the pressure regulator has a flat surface that adjusts the reflux rate. 3. The surface 73 on which the spring 63 is received is located at the lower end of the spherical portion 72, and is on a plane parallel to the diameter surface of the sphere and moved toward the cylindrical portion 70 from a plane that includes the center of the spherical surface. A pressure regulator according to claim 1 or 2. 4. The spring 63 which brings the valve body 7 into contact with the wall of its storage chamber 80 is characterized in that it is supported at its lower end by a circular edge plane 62 forming part of the return nozzle 6. Claim 1
The pressure regulator according to item 1, 2 or 3. 5. Claim 1, characterized in that the valve body 7 has a second plane part 71 parallel to its closing/adjusting plane part 75, and a cylindrical part 70 is provided on this plane. Pressure regulator as described in section.