JPS6038047Y2 - Pump nozzle for internal combustion engine - Google Patents

Description

[Detailed description of the invention] The present invention controls a servo piston having a larger diameter than the plunger by a solenoid valve, and injects high-pressure fuel generated by the plunger interlocking with the servo piston from an injection nozzle. The present invention relates to the structure of a pump nozzle for an internal combustion engine.

As a conventional pump nozzle of this type,
5254 and Japanese Patent Publication No. 54-26651 are known, but each of these conventional fuel injection devices has the following drawbacks.

That is, the pump nozzle of Japanese Patent Publication No. 54-35254 shown in FIG. Since the hydraulic pressure acting on the end face 206 of the slide valve 202 is adjusted by opening and closing the outflow port 204 and inflow port 205 of the spherical movable valve 203 interlocked with the slide valve 201, the inflow port area of the movable valve 203 is adjusted. In order to increase the mass of the moving parts 201 and 202, a more powerful solenoid 211 is required to make the moving parts more powerful.
In addition, since the pressure receiving area of the movable valve 203 becomes large, the solenoid valve 201 needs to be a pressure balance type, which complicates the structure of the fuel injection device itself and reduces durability, that is, the worn surface of the movable part 203. There were problems with durability, such as rotation of the valve, resulting in poor oil sealing, and wear, which caused the valve seat diameter to change, resulting in loss of pressure balance.

(2) Since the inflow port 211 and the outflow port 212 of the servo piston chamber 207 are shared by the single control hole 208,
There is a problem in that the conical protrusion 201 formed on the servo piston 209 to control the injection pattern during the injection stroke also has an effect during the filling stroke.

In the pump nozzle of Japanese Patent Publication No. 54-26651 shown in FIG. 21, valves 301 and 306 that are linked to a solenoid valve 305 directly open and close an inlet 303 and an outlet 302 of a servo piston chamber 304. Therefore, the size of the inlet 303 and outlet 302 of the servo piston chamber 304 is limited by the pressure load of the solenoid valve 305 and the suction force of the solenoid 307, so a large amount of fuel can be injected at high pressure by shortening the fuel injection time. difficult to do.

In view of the problems of conventional fuel injection devices as described above, the present invention has been developed to control the amount and timing of fuel injection and the rotation of the engine by opening and closing the inlet of the servo piston chamber with a conical valve controlled by a solenoid valve. The engine speed can be optimally controlled over the entire operating range of the engine, and
The main purpose is to provide a pump nozzle for an internal combustion engine that has a simple structure, is small and lightweight, and which facilitates high-pressure injection of fuel.Furthermore, in such a pump nozzle, it is possible to adjust the valve lift of the solenoid valve. Another purpose of this invention is to make it possible to adjust the injection characteristics of the pump nozzle by doing so.

Hereinafter, the pump nozzle for an internal combustion engine of the present invention will be explained based on the first embodiment of the present invention shown in FIGS. 1 to 12 and the second embodiment of the present invention shown in FIGS. 13 to 19.
FIG. 1 shows a fuel injection device Z having a pump nozzle according to a first embodiment of the present invention, which is mounted on the cylinder head of a diesel engine Y. As shown in FIG.

This fuel injection device Z has a nozzle installed in a pump nozzle mounting hole 6 provided in a cylinder head 2 with the nozzle at its tip facing into a working chamber 4 formed above a piston 5 in a cylinder block 1. From a controller 20 that controls a pump nozzle X attached by a presser foot 13, a fuel supply pump 18 disposed outside the diesel engine Y, and a solenoid valve (described in detail later) housed in the pump nozzle. The fuel in the fuel tank 19 is sent by the fuel supply pump 18 through the fuel pipe 10 and the fuel supply pipe 11 into the pump nozzle The solenoid valve of the pump nozzle X is controlled by the controller 20 in accordance with the input signal, and a predetermined amount of fuel is injected into the working chamber 4.

The structure of this pump nozzle X will be explained in detail below.

The pump nozzle X is connected to the nozzle valve 3 as shown in FIG.
2, a pump section 55 having a plunger 59 and a servo piston 60 for driving the plunger 59, and a servo piston 60 of the pump section 55.
A control unit 10 having a solenoid valve 111 that controls
5 are sequentially connected coaxially.

As shown in FIGS. 2, 4, and 7, the injection nozzle section 30 includes a nozzle body 31 into which a nozzle valve 32 is slidably inserted, a short-axis nozzle stop spacer 33, and an injector cage 34. A nozzle spring seat is provided in a nozzle spring seat insertion hole 40 that communicates between the nozzle stop spacer 33 and the injector cage 34, and which normally biases the nozzle valve 32 in the closing direction with a spring 36. 39 is fitted.

The nozzle body 31, nozzle stop spacer 33, and injector cage 34 are integrally fastened to the tip of a plunger body 58, which will be described later, by a nozzle mounting nut 35.

The end surface 33a of the nozzle stop spacer 33 on the nozzle body 31 side acts to restrict the upper limit of the lift of the nozzle valve 32 by abutting against the upper end surface 32a of the nozzle valve 32.

A plunger chamber 67 and a phytovalve chamber 68 of a plunger body 58, which will be described later, are provided on the upper end surface of the injector cage 34.
a groove 41 extending in the radial direction so as to communicate with each other;
is formed.

Further, this groove 41 is connected to an oil reservoir formed at the tip of the nozzle body through a vertical hole 42 of the injector cage 34, a diagonal hole 43 of the nozzle stop spacer 33, an annular groove 44 and a diagonal hole 45 of the nozzle body 31. It communicates with the inside of the chamber 38.

An oil passage 46 extending from the groove 41 to the oil reservoir chamber 38 is for sending pressurized high-pressure fuel into the oil reservoir chamber 38, and hereinafter, this oil passage 46 will be referred to as a high-pressure fuel passage 46.

In addition, as shown in FIG. 7, a diagonal hole 47 is formed on the upper end surface of the injector cage 34 outside the groove 41 to communicate the nozzle spring seat insertion hole 40 with a diagonal hole 83 of a plunger body 58, which will be described later. ing.

In addition, the reference numeral 37 is a shim for adjusting the spring 36, and 48.4
Reference numeral 9 indicates a parallel pin for positioning the plunger body 58, injector cage 34, and nozzle stop spacer 33 in the circumferential direction, and 49 indicates a nozzle hole.

As shown in FIGS. 2 to 5 and 7, the pump section 55 includes a plunger body 58 having a plunger chamber 67 for accommodating a plunger 59, and a servo piston 6.
Bolts 85, 85... (
(Fig. 5), they are fastened and fixed coaxially.

A servo piston chamber 76 formed by penetrating the servo piston body 57 in the axial direction is connected to the plunger body 58.
The plunger chamber 67 is coaxially communicated with a plunger chamber 67 formed by passing through the plunger chamber 67 in its axial direction.

A large-diameter servo piston 60 is placed in the servo-piston chamber 76, and a small-diameter plunger 59 is placed in the plunger chamber 67.
are fitted into each other so as to be slidable in the axial direction, and the servo piston 60 and plunger 59 integrally reciprocate in response to the pressure of fuel flowing into and out of the servo piston chamber 76 and the plunger chamber 67. It will be done.

The fuel injection pressure is determined by the cross-sectional area ratio of the servo piston 60 and the plunger 59.

Further, the servo piston chamber 76 and the plunger chamber 67 are formed eccentrically by an appropriate dimension with respect to the axes of the servo piston body 57 and the plunger body 58, respectively.

The conical valve body 56 has a horizontal hole 71 of an appropriate depth formed in the radial direction from one side thereof, and the fuel supply pipe 11 is screwed into the outer end of the horizontal hole 71.

This horizontal hole 71 is a passage for receiving fuel pumped from the fuel supply pump 18, and hereinafter, this horizontal hole 7
1 is referred to as a supply fuel passage 71.

A conical valve chamber 84 is provided at the axial center of the conical valve body 56 so as to communicate orthogonally with the supply fuel passage 71.
and the servo piston chamber inflow lower 7 are formed coaxially.

This servo piston chamber inflow lower 7 is formed so that the top surface of the servo piston 60 fitted into the servo piston chamber 76 can be viewed from the servo piston chamber inflow lower 7, and the top surface of the servo piston 60 fitted into the servo piston chamber 76 can be viewed from the servo piston chamber inflow lower 7. The opening end surface serves as a valve seat 79 for a conical valve 61, which will be described later.

On the other hand, the conical valve chamber 84 extends from the upper end surface of the conical valve body 56 toward the fuel supply passage 71, and the conical valve 61 is fitted into the conical valve chamber 84 so as to be slidable in the axial direction. It is inserted.

The conical valve 61 is formed into a bottomed cylindrical shape with the supply fuel passage 71 side closed, and is moved up and down by controlling the back pressure in the conical valve chamber 84, and its tip is connected to the servo piston chamber 84 so that it can flow into the servo piston chamber. It acts to open and close the servo piston chamber inflow lower 7 by seating or separating the valve seat 79 of the lower 7.

This conical valve 61 is always biased toward the conical valve seat 79 with an appropriate biasing force by a spring 65 fitted inside the conical valve 61.

Further, one end of the conical valve chamber 84 is closed by the lower end surface of a disc-shaped solenoid valve seat 106 attached to the outer end surface thereof.

The solenoid valve seat 106 has an axial through hole 144, 144 communicating with the conical valve chamber 84;
A horizontal hole 141 extending through the solenoid valve seat 106 in the radial direction thereof and the solenoid valve seat 10
A communication hole 142 that communicates with the upper end surface of 6 is formed.

This through hole 144 serves as an outflow passage for the fuel accommodated in the conical valve chamber 84, and is provided by the solenoid spacer 1 placed on the upper part of the solenoid valve seat 106.
It is communicated with a through hole 145 provided in the axial center of 07.

On the other hand, the communication hole 142 serves as a fuel introduction port 142 for introducing fuel into the conical valve chamber 84.
The upper end opening serves as a valve seat 143 of the solenoid valve 111 which will be described later, while the other end communicates with an annular groove 140 formed on the lower circumferential surface of the solenoid valve seat 106 so as to communicate with the horizontal hole 141. The conical valve body 56 communicates with the fuel supply passage 71 through an oblique hole 97 .

Therefore, when the fuel inlet 142 is open, the fuel in the supply fuel passage 71 enters the through hole 145 of the solenoid spacer 107 through the oblique hole 97, the annular groove 140, the horizontal hole 141, and the fuel inlet 142. Furthermore, the through hole 14
5 to the through hole 144 of the solenoid valve seat 106,
144 into the conical valve chamber 84.

Hereinafter, from this supply fuel passage 71 to the conical valve chamber 84
A series of oil passages 139 leading to the conical valve chamber fuel introduction passage 139 (FIG. 3).

Note that when the fuel inlet 142 is closed, the fuel accommodated in the conical valve chamber 84 flows through the through holes 144, 1.
44 through the through hole 145 of the solenoid spacer 107
The fuel enters the inside and is further discharged to the fuel return pipe 124 side through an oil passage 152 formed in the axial center of the static core 110 of the control section 105, which will be described later.

On the other hand, an annular groove 80 of an appropriate width is formed on the sliding surface of the conical valve 61 against the chamber wall of the conical valve chamber 84.

This annular groove 80 is connected to the conical valve 6 as shown in FIG.
When the conical valve 61 is closed, it communicates with the oil escape hole 88 formed by penetrating the conical valve chamber 84 in its radial direction, and when the conical valve 61 is opened, it is in a non-communicating state. The formation position in the axial direction is set appropriately.

One end of this oil escape hole 88 is a servo screw. Ton chamber outlet 8
The other end is connected to an external fuel tank 19 via an orifice 89 and a groove 90 formed in the lower end surface of the conical valve body 56 .

Hereinafter, this servo piston chamber outlet 87, annular groove 80,
A series of oil passages 94 consisting of the oil relief holes 88 and the grooves 90 is referred to as a hydraulic oil relief passage 94.

Further, the groove 90 is communicated with the back pressure side of the servo piston 60 via the vertical hole 92 of the servo piston body 57 and the diagonal hole 93 of the plunger body 58, and leakage oil from the servo piston 60 flows through the vertical hole 92 and the diagonal hole 93 of the plunger body 58. It passes through the oblique hole 93 and is discharged to the fuel tank 19 side.

Therefore, when the conical valve 61 is opened, the servo piston chamber outlet 87 is closed, so that the fuel introduced into the servo piston chamber 76 from the servo piston chamber inflow lower 7 is caused by the fuel pressure to cause the servo piston 60 to
The conical valve 6
When valve 1 is closed, servo piston chamber outlet 87 is opened, so servo piston 60 is moved upward by the pressure of fuel introduced into plunger pump chamber 67 via feed valve 69, which will be described later.

Further, a feed valve chamber 68 is formed at the lower end of the plunger body 58 so that one end thereof opens into the groove 41 of the injector cage 34 .

This feed valve chamber 68 is communicated with the plunger chamber 67 via the groove 41.

Further, the upper end of the feed valve chamber 68 is connected to the diagonal hole 74 of the plunger body 58 and the vertical hole 73 of the servo piston body 57.
The conical valve body 56 also communicates with the supply fuel passage 71 through a vertical hole 72 .

A feed valve 62 having small holes 69 and 69 is fitted in the feed valve chamber 68, and the feed valve 62 is normally biased in the valve closing direction by the spring force of the spring 64.

A series of oil passages 70 extending from the supply fuel passage 71 to the feed valve chamber 68 are for filling the plunger chamber 67 with fuel, and hereinafter, this oil passage 70 will be referred to as a fuel filling passage 70.

Further, as shown in FIG. 7, the pump portion 55 is formed with an oil passage 86 that directly communicates the fuel supply passage 71 with the nozzle spring seat insertion hole 40 of the injector cage 34.

The oil passage 86 (FIG. 7), which is composed of the diagonal hole 81 of the conical valve body 56, the vertical hole 82 of the servo piston body 57, the diagonal hole 83 of the plunger body 58, and the diagonal hole 47 of the injector cage 34, is connected to the nozzle valve. 32 is the mounting load of the nozzle spring 36 and the nozzle valve 3.
In order to generate the back pressure determined by the sum of the back pressure load of 2, the nozzle spring seat insertion hole 40 is
Hereinafter, this oil passage 86 will be referred to as a nozzle valve biasing fuel passage 86.

Note that the reference numeral 63 indicates a parallel pin for positioning the conical valve body 56, the servo piston body 57, and the plunger body 58 in the circumferential direction.

As shown in FIGS. 2 and 3, the control unit 105 includes a solenoid coil 116 whose excitation timing and excitation time are controlled by the controller 20, and a solenoid valve 111 which is driven to open and close by the attraction force of the solenoid coil 116. It is configured.

The solenoid valve 111 has needle-shaped valve bodies 135 at both ends.
. is forming.

This solenoid valve 111 has a valve body 136 side having a long four-way sliding portion inserted into a straight cylindrical active core 112 having a stepped inner circumferential surface from its large-diameter inner circumferential surface side, and a flange 137 of the active core 112. The stepped end face 112 of the inner peripheral surface of
It is brought into contact with a.

Further, a flanged, elongated cylindrical starter core 110 is fitted onto the valve body 136 side that protrudes downward from the lower end surface of the active core 112, with a lower spring 113 interposed between it and the active core 112. There is.

The static core 110 and active core 112 are
As shown in FIG. 9, the core guide 109 is fitted into a core insertion hole 162 of a core guide 109 having a slender, cylindrical shape with a flange.

Further, the upper part of this core guide 109 is a small diameter screw hole 164 that is continuous with the core insertion hole 162.
An upper seat 119 having an oil escape hole 148 formed in its axial center is fitted into the upper seat 64 .

As shown in FIG. 10, the upper sheet 119 has an upper threaded portion 119a and a lower threaded portion 119b formed at both ends of a shaft body of an appropriate length, and is formed in the threaded hole 164 of the core guide 109. The lower threaded portion 119b is screwed together, and the upper threaded portion 119a is made to protrude outward from the upper end surface 109a of the core guide 109.

A lock nut 121 is screwed onto the outwardly projecting upper threaded portion 119a.

This upper seat 119 is attached to a slotted portion 11 formed on the end surface of the upper threaded portion 119a by loosening the lock nut 121.
By inserting a tool such as a screwdriver into 9c and turning it appropriately, the relative position in the axial direction with respect to the core guide 109 can be changed and the upper limit position of the solenoid valve 111(7), that is, the valve lift can be appropriately set.

That is, in this embodiment, the upper seat 119 is used as an adjustment member for adjusting the operating range of the solenoid valve 111.

Note that the end surface 149 of the oil escape hole 148 on the lower threaded portion 119b side
acts as a valve seat for the solenoid valve 111.

Further, the core guide 109 is connected to the conical valve body 5.
The lower support 115 screwed onto the solenoid spacer 1 along with the flange of the static core 110
It is fastened and fixed to 07.

Between the upper seat 119 and the flange of the solenoid valve 111, there is an upper spring 1 having a spring constant and a load at the time of installation smaller than that of the lower spring 113.
14 is fitted.

At this time, the upper valve body 135 of the solenoid valve 111
is on the valve seat 149 of the upper seat 119, and
Since the lower valve body 136 is placed close to and opposed to the valve seat 143 of the solenoid valve seat 106 so as to be seated on each valve seat 143, the solenoid valve 111 is always connected to the active core 112 due to the difference in spring force between the upper spring 114 and the lower spring 113. The oil escape hole 148 is integrally urged toward the upper seat 119 side.
It is designed to close the valve.

The oil escape hole 148 of the upper seat 119 is connected to the communication hole 147 of the active core 112 and the solenoid valve insertion hole 1 of the hysteretic core 110.
The solenoid valve seat 106 is communicated with the through hole 144 of the solenoid valve seat 106 through a communication hole 152 (FIG. 8) formed between the solenoid valve seat 51 and the four-way sliding portion of the solenoid valve.

From the through hole 144 of the solenoid valve seat 106 to the internal space 150 of the upper support 118 screwed to the outside of the upper seat 119, and further from the internal space 150 to the one-eye pipe joint 123, a series of communication paths are connected to the conical valve chamber outflow path. It's called 165.

At this time, the valve seat 14 of the upper seat 119
Since 9 acts as a discharge port for discharging fuel oil from inside the conical valve chamber 84, hereinafter, valve seat 1
49 is called a fuel discharge port 149.

A cylindrical solenoid coil 116 is fitted in a space 115a formed between the lower support 115 and the core guide 109 to open and close the Tsuremade valve 111 using its suction force.

This solenoid coil 116 is connected to the solenoid coil 1
The axial center of the active core 112 is located below the axial center of the active core 112 so that the active core 112 can be attracted and moved downward when the active core 16 is excited.

Therefore, when the solenoid coil 116 is excited, the solenoid valve 111 is pulled down together with the active core 112 due to its attractive force, and the lower valve body 13
6, the fuel inlet 143 of the conical valve chamber 84 is closed, and at the same time, the fuel outlet 149 is opened.

Furthermore, when the solenoid coil 116 becomes de-energized, its attractive force is released, so the solenoid valve 111 is pulled upward again by the difference in spring force between the lower spring 113 and the upper spring 114, and the fuel in the conical valve chamber 84 is pulled up again. At the same time as opening the introduction port 143,
It acts to close the fuel discharge port 149.

At this time, by screwing the upper seat 119 to change the relative position in the axial direction with respect to the solenoid valve 111, the valve opening degree and valve stroke of the solenoid valve 111 can be adjusted as appropriate.

In addition, code 10.10a. In the case of a multi-cylinder engine, 10b and 10c are fuel pipes for each cylinder, 117 is a yoke, 120 is a coupling nut for integrally coupling the core guide 109 and the lower support 115, and 121 is a coupling nut for the upper seat 119. Lock nut, 122 is a pipe joint bolt, 124, 124a, 124b, 124c are fuel return pipes for each cylinder, 126 is a solenoid coil 116
The connection terminals are shown respectively.

Next, the operation and effect of the fuel injection device for an internal combustion engine having a pump nozzle according to the first embodiment of the present invention will be explained using FIGS. 11 and 12 (simplified diagrams of the fuel injection device). , this fuel injection device Z supplies fuel in a fuel tank 19 to a pump nozzle X using a fuel supply pump 18 driven by an internal combustion engine Y, and a flywheel 22 of the fuel injection device Z so as to synchronize with the rotation of the internal combustion engine Y. The solenoid valve 111 in the pump nozzle X is controlled by the controller 20 according to the signal from the sensor 21 attached to the
It is designed to open and close as appropriate.

Note that the supply pressure of the supplied fuel is appropriately set by the pressure regulating valve 24, and the pressure pulsations thereof are absorbed by the accumulator 25.

First, the operation of the pump nozzle X when the solenoid coil 116 is energized will be explained with reference to FIG.
to lower the fuel inlet 14 of the conical valve chamber 84.
At the same time as the valve 3 is closed, the fuel discharge port 149 thereof is opened.

When the fuel discharge port 149 opens, the conical valve chamber 84
The fuel oil stored in the conical valve chamber passes through the fuel discharge passage 165 and is discharged from the fuel return pipe 124 to the fuel tank 1.
It flows out to the 9th side.

When fuel oil flows out from inside the conical valve chamber 84, a pressure difference is generated before and after the conical valve 61, and the conical valve 61 is moved higher than the fuel pressure inside the supply fuel passage 71 to open the inflow lower 7 of the servo piston chamber 76. speak.

When the servo piston chamber outlet port a 7 is opened, the fuel oil in the supply fuel passage 71 is introduced into the servo piston chamber 76 .

At this time, since the servo piston chamber outlet 87 is closed by the sliding surface of the conical valve 61, the servo piston 60 is pushed downward by the fuel oil.

When the servo piston 60 is pushed down, the plunger 59 is also pushed down together with the servo piston 60.

When the plunger 59 is moved downward, the plunger chamber 6
The fuel oil in the nozzle oil storage chamber 38 is pressurized, and the feed valve 62 is closed by the fuel pressure, and the fuel pressure in the nozzle oil reservoir chamber 38 is rapidly increased, causing the nozzle valve 32 to close.
When the valve is opened, the fuel in the plunger chamber 67 is sequentially passed through the high pressure fuel passage 46 and injected into the working chamber 4 from the injection ports 49, 49, . . . .

When the plunger 59 is lowered to the lower lift limit position, the fuel pressure in the nozzle oil reservoir chamber 38 decreases, causing the nozzle valve 32 to drop.
The nozzle valve 32 is closed by the urging force of the spring 36 acting on the nozzle valve 36 and the pressure of the fuel oil flowing into the nozzle prefix seat insertion hole 40 through the nozzle valve urging fuel passage 86, and the fuel injection is completed. do.

Next, referring to FIG. 12, the pump nozzle X when the solenoid coil 116 is turned off from the energized state.
To explain the operation, when the solenoid coil 116 is de-energized, the attraction force to the solenoid valve 111 is released, so the solenoid valve 111 is moved upward by the spring force and opens the fuel inlet 143 of the conical valve chamber 84. valve, and close the fuel discharge port 149.

When the fuel inlet 143 is opened, the fuel oil in the supply fuel passage 71 flows into the conical valve chamber 84 from the conical valve chamber fuel inlet passage 139, and the fuel pressures before and after the conical valve 61 are balanced, and the conical valve 61 is moved downward by the spring force of the spring 65 to close the servo piston chamber inflow lower 7.

When the conical valve 61 moves downward, the annular groove 80 formed on its sliding surface communicates with the oil escape port 88, so the servo piston chamber outlet 87 is opened, and the fuel oil in the servo piston chamber 76 is filled with fuel oil. The fuel tank 19 passes through the relief passage 94.
The hydraulic pressure inside the servo piston chamber 76 drops.

Then, the hydraulic pressure in the plunger chamber 67 also decreases accordingly.

For this purpose, the high-pressure fuel oil in the fuel filling passage 70 pushes the feed valve 62 open with its fuel pressure, causing the plunger chamber 6 to open.
7 is filled with the fluid by moving the plunger 59 and servo piston 60 upward.

By sequentially repeating the injection process shown in FIG. 11 and the filling process shown in FIG. 12, the internal combustion engine Y is continuously operated.

Further, the injection amount of the pump nozzle X is determined by the fuel filling time, that is, the return stroke length of the plunger 59.

This filling time is adjusted by appropriately setting the energization cut-off time of the solenoid coil 116, and the return speed of the servo piston 60 is adjusted by the orifice 89 provided in the fuel oil relief passage 94. It is regulated by throttling the spilled fuel accordingly.

Next, the pump nozzle of the second embodiment of the present invention shown in FIGS. 13 to 19 will be explained. In the pump nozzle of the second embodiment, as shown in FIG. The basic structure is the same as that of the first embodiment, except that the conical valve 61 controlled by the conical valve 111 opens and closes to drive the servo piston 60 and inject fuel at high pressure from the injection nozzle part 30. Only the back pressure control method 61 is different from that of the first embodiment.

That is, as shown in FIG. 14, the conical valve 61 of the pump nozzle A hole 156 is formed, and this through hole 156 is connected to the fuel inlet 1 of the conical valve chamber 84.
56, and a fuel outlet 155 from the conical valve chamber 84 having a larger diameter than the fuel inlet 156 is formed in a solenoid valve seat 128 attached to close the upper open end of the conical valve chamber 84. There is.

Of the fuel inlet 156 and the fuel outlet 155, only the fuel outlet 155 is connected to the solenoid valve 111 integrally connected to the active core 131 that is moved vertically by the suction force of the solenoid coil 116.
It is opened and closed by a valve body 136.

That is, the back pressure of the conical valve 61 fitted in the conical valve chamber 84 is controlled by appropriately opening and closing the fuel outlet 155 of the conical valve chamber 84 using the Tsuremade valve 111. 61
The conical valve 61 opens and closes the servo piston chamber outlet port 7 by moving the conical valve 61 forward and backward.

Incidentally, the fuel oil flowing out from the fuel outlet 155 is transferred to the static core 1 attached to the axial center of the solenoid coil 116.
The fuel is discharged to the fuel return pipe 124 side through the communication hole 148 of No. 33.

Further, the valve opening degree and valve stroke of the solenoid valve 111 are regulated by the lower end surface 133d of the static core 133 inserted into the core guide 130 and the upper end surface 131a of the active core 131 coming into contact with each other.

As shown in FIG. 17, this static core 133 is composed of a shaft body of an appropriate length having an oil escape hole 148 in its axial center, and has a threaded portion 133b in its upper part and a core part in its lower part. Core insertion hole 163 of guide 130 (see Figure 16)
A sliding surface 133a is formed against the sliding surface 133a.

The static core 133 is attached to the core guide 130 by screwing its threaded portion 133b into the threaded hole 130a of the core guide 130, and the tip protrudes upward from the upper end surface 130b of the core guide 130. A lock nut 121 is screwed onto the part.

This starter core 133 is assembled by loosening the lock nut 121 and inserting the slotted portion 13 formed on the end surface of the threaded portion 133b.
By inserting a tool such as a screwdriver into 3c and turning it appropriately, the relative position in the axial direction with respect to the core guide 130 can be changed, and the valve lift of the solenoid valve 111 can be appropriately set.

That is, in this second embodiment, the static core 1
33 is used as a valve lift adjustment member for the solenoid valve 111.

When the solenoid coil 116 is excited, the pump nozzle
The solenoid valve 111 is moved upward by the suction force of 6, and the fuel discharge port 155 of the conical valve chamber 84 is opened.As a result, the fuel oil in the conical valve chamber 84 flows out from the fuel discharge port 155, and at the same time, the fuel oil is supplied. Fuel oil in the fuel passage 71 flows into the conical valve chamber 84 from the fuel inlet 156.

At this time, the passage area of the fuel inlet 156 is reduced to the area of the fuel outlet 156.
5, the fuel pressure in the conical valve chamber 84 becomes lower than the fuel pressure in the supply fuel passage 71, and this fuel pressure difference causes the conical valve 61 to move upward, causing the servo The piston chamber inflow lower 7 is opened.

On the other hand, when the solenoid coil 116 is de-energized from the energized state, the attraction force of the solenoid coil 116 to the solenoid valve 111 is released, so the solenoid valve 111 is pushed down by the spring force of the spring 132 and the conical valve chamber 84 The fuel discharge port 155 of the engine is closed.

When the fuel discharge port 155 is closed, the fuel pressure before and after the conical valve 61 is balanced, and the conical valve 111
is moved downward by a spring 65 and acts to close the servo piston chamber inflow lower 7.

Note that the servo piston chamber inflow lower 7 is a conical valve 61.
The operating state of each part of the pump nozzle X after the valve is opened or closed is the same as in the first embodiment, and therefore the explanation thereof will be omitted.

Further, in FIG. 11, reference numeral 130 indicates a core guide;
3 indicates a static core, and all other members correspond to the respective members shown in FIG. 2 of the first embodiment.
Please refer to the description section of the first embodiment.

In the pump nozzle X shown in the first and second embodiments, the servo piston chamber inflow lower 7 is opened and closed by a conical valve 61, so that the diameter of the servo piston chamber inflow lower 7 can be made large. Moreover, the valve seat 79 of the conical valve 61 can be connected to the servo piston chamber 7.
6, the fuel oil can be quickly introduced into the servo piston chamber 76, and the fuel can be injected at high pressure in a short time.

Further, since a portion of the fuel oil is directly allowed to flow into the nozzle spring seat insertion hole 40, the mounting portion of the nozzle spring 36, which determines the opening pressure of the nozzle valve 32, can be made small and compact.

Furthermore, since the oil flowing out from the conical valve chamber 84 is made to flow through the conical valve chamber outflow passage 165 formed at the axial center of the solenoid coil 116, the solenoid coil 116 is cooled by the oil flowing out, and the solenoid coil 116 is cooled. It is possible to prevent a decrease in the suction capacity due to a rise in the temperature of the coil 116, and it is possible to operate the Tsuremade valve 111 more reliably.

In addition, the valve lift of the solenoid valve 111 is controlled by a valve lift adjusting member (in the first embodiment, the upper seat 1
19. In the second embodiment, the static core 133)
Therefore, even if there is variation in valve lift due to processing errors between pump nozzles, it can be easily corrected by the valve lift adjustment member.

Next, to explain the effects of the pump nozzle for internal combustion engines of the present invention, the pump nozzle of the present invention is a solenoid valve that is driven to open and close by a solenoid coil, and is designed to adjust the back pressure of a conical valve that controls the operation of a servo piston. Therefore, the valve seat area of the solenoid valve can be reduced and a solenoid coil with a small suction load can be used, which has the effect of making the solenoid part smaller and lighter.

Furthermore, since the inlet of the servo piston chamber is opened and closed by a conical valve placed opposite to the inlet,
The ratio of the change in the opening area A of the servo piston chamber inlet to the change in the valve lift L of the conical valve dA/d
L is a slide valve 2 like the conventional example shown in FIG.
When opening and closing the inlet 211 of the servo piston chamber in 02, and when the mass of the moving body is almost the same as that of the conical valve, the change in the inlet opening area A with respect to the change dS in the stroke S of the slide valve (ratio dA of [JA /dS, the fuel oil can be introduced into the servo piston chamber more quickly, the fuel injection time can be shortened, and the fuel can be injected at a higher pressure.

In addition, the valve lift of the solenoid valve that controls the opening and closing of the conical valve can be easily adjusted using a valve lift adjustment member, so even if there are variations in valve lift due to processing errors in the pump nozzle, it is possible to easily adjust the valve lift. This can be corrected with a valve lift adjustment member, and has the practical effect of appropriately adjusting the injection characteristics of the pump nozzle.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of essential parts of an internal combustion engine equipped with a fuel injection device having a pump nozzle according to an embodiment of the present invention, FIG. 2 is a vertical cross-sectional view of the pump nozzle of the fuel injection device shown in FIG. 1, and FIG.
The figure is an enlarged view of part ■ in Fig. 2, Fig. 4 is an enlarged view of part -■ in Fig. 2, Fig. 5 is a sectional view of the main part taken along line V-V in Fig.
Figure 7 is the ■-■ longitudinal sectional view of Figure 6, and Figure 8 is the
The figure is a cross-sectional view taken along the line ■-■ of Fig. 3, Fig. 9 is a vertical sectional view of the core guide shown in Fig. 3, Fig. 10 is a perspective view of the upper seat shown in Fig. 3, and Figs. 11 and 12. 13 is a vertical sectional view of the pump nozzle of the fuel injection device according to the second embodiment of the present invention, FIG. 14 is an enlarged view of section XIV in FIG. 13, and FIG. The figure is an enlarged view of section XV in Fig. 13, Fig. 16 is a vertical cross-sectional view of the core guide shown in Fig. 13, Fig. 17 is a perspective view of the static core shown in Fig. 13, and Figs. 18 and 19. 11 is an explanatory diagram of the operation of the pump nozzle, and FIGS. 20 and 21 are explanatory diagrams of the structure of a conventional pump nozzle. 32... Nozzle valve, 59... Plunger, 60... Servo piston, 61...
... Conical valve, 62 ... Feed valve, 67 ... Plunger chamber, 76 ...
Servo piston chamber, 77... Servo piston chamber inlet, 84... Conical valve chamber, 87...
...Servo piston chamber outlet, 111...
Solenoid valve, 109, 130... Core guide, 112, 131... Active core, 11
9.133... Valve lift adjustment member.

Claims (1)

[Scope of utility model registration request] The fuel oil supplied from the fuel input lower 1 is transferred to the feed valve 6.
2 into the plunger chamber 67, the fuel oil is pressurized by the plunger 59 which reciprocates in conjunction with the servo piston 60, and the servo piston is further inserted into the servo piston chamber 76 which accommodates the servo piston 60. A servo piston chamber inflow lower 7 for introducing a portion of the supplied fuel, which becomes the working oil of 60, into the servo piston chamber 76 and a servo piston chamber outlet 87 for discharging the supplied fuel from the servo piston chamber 76. On the other hand, a conical valve 61 for opening and closing the servo piston chamber inflow lower 7 is disposed facing the servo piston chamber inflow lower 7 to introduce fuel oil into the conical valve chamber 84 accommodating the conical valve 61. The discharge causes the conical valve 61 to close or open the servo piston chamber inflow lower 7, and the introduction and discharge of fuel oil into the conical valve chamber 84 is controlled by electricity transmitted in synchronization with the rotation of the engine. Active core 11 driven by a solenoid coil 116 whose excitation is controlled by a target signal
A pump nozzle for an internal combustion engine is controlled by a solenoid valve 111 that is integrally displaced with the pump nozzle 2,131, and further injects fuel oil pressurized by the plunger 59 from the nozzle valve 32, a core guide 109 into which the active cores 112, 131 and the solenoid valve 111 are slidably inserted;
A suitable valve lift adjustment member 119, 133 is screwed into the solenoid valve 111 or the active core 112, 131 so as to be in opposing contact with the valve lift adjustment member 119, 133 and the core guides 109, 13.
A pump nozzle for an internal combustion engine, characterized in that the valve lift of the solenoid valve 111 can be adjusted by changing the relative position in the axial direction with respect to the solenoid valve 111.