JPS6039489Y2 - 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. This invention relates to the structure of a pump nozzle used in a fuel injection device for an internal combustion engine.The inlet of the servo piston chamber is opened and closed by a Konica valve controlled by a solenoid valve, thereby controlling the amount and timing of fuel injection and the engine. The main objective is to provide a pump nozzle for an internal combustion engine that can be optimally controlled over the entire rotational speed range, and further, in such a pump nozzle for an internal combustion engine,
By forming a protrusion of an appropriate size on the valve head of the Konica valve and appropriately changing the passage area for fuel flowing into the servo piston chamber, the fuel injection rate during the pre-injection period and the main injection can be controlled. Another purpose of this design is to enable the fuel injection during the period to be set to an optimum value, thereby improving the fuel injection characteristics of the pump nozzle.

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 13 and the second embodiment of the present invention shown in FIGS. 14 to 17.
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 a cylinder head portion of a diesel engine Y. As shown in FIG.

This fuel injection device Z has a nozzle installed in a pump nozzle mounting hole 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, which is sent by the fuel supply pump 18 into the pump nozzle The controller 20 controls the solenoid valve of the pump nozzle X in accordance with the input signal, so that 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 36 is installed in a nozzle spring seat insertion hole 40 that communicates with the nozzle stop spacer 33 and the injector cage 34 to normally bias the nozzle valve 32 in the closing direction. A sheet 39 is inserted.

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, on the upper end surface of the injector cage 34, outside of the groove 41, as shown in FIG. has been done.

In addition, the reference numeral 37 is a shim for adjusting the spring 36, and 48.4
Reference numeral 8 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... (5th
(Fig.) are configured by fastening and fixing them coaxially.

A servo piston chamber 76 formed by penetrating the servo piston chamber day 57 in the axial direction is coaxially communicated with a plunger chamber 67 formed by penetrating the plunger body 58 in the 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 in 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 71 will be 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 in a bottomed cylindrical shape with the supply fuel passage 71 side closed, as shown in FIGS. The servo piston chamber inflow lower 7 is moved up and down along the chamber wall of the conical valve chamber 84, and the slope formed on the valve head 61e is seated on or separated from the valve seat 79 of the servo piston chamber inflow lower 7. It acts to open and close.

A protrusion 61a of an appropriate size is integrally formed on the valve head 61e of the conical valve 61.

This protrusion 31a is for fuel that advances and retreats in the axial direction of the servo piston chamber inflow lower 7 as the conical valve 61 opens and closes, and flows into the servo piston chamber 76 from the supply fuel passage 71. The first throttle portion 61b has a diameter slightly smaller than the inner diameter dimension of the servo piston chamber inflow lower 7.
, a second throttle part 61b having a smaller diameter than the first throttle part 61b, and an inclined shaft part 61c formed between the first throttle part 61b and the second throttle part 61b.
It is composed of

The shape of the second throttle 61b is not limited to the straight shaft shape shown by the solid line in FIG.
It can also be formed so that the diameter becomes gradually smaller toward the tip.

In this manner, by appropriately setting the shape of the second throttle portion 61d, it is possible to change the fuel throttling characteristics and, by extension, the initial fuel injection characteristics at the initial stage of opening of the conical valve 61.

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

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 penetrated 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.
An annular groove 140 is formed in the lower side surface of the solenoid valve seat 106 so that its upper end opening is a valve seat 143 of a solenoid valve 111, which will be described later, and the other end is in communication with a horizontal hole 141. The supply fuel passage 71 is communicated with the valve body 56 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 narrow part 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 connected to the servo piston chamber outlet 87.
The other end communicates with the servo piston chamber 76 through the orifice 89 and the conical valve body 5.
It is connected to an external fuel tank 19 via a groove 90 formed on the lower end surface of the fuel tank 6 .

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 communicates with the back pressure side of the servo piston 60 via a vertical hole 92 of the servo piston body 57 and an oblique hole 93 of the plunger body 58.
The leaked oil of 0 is discharged to the fuel tank 19 side through the vertical hole 92 and the oblique hole 93.

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 chamber 67 via feed valve 62, which will be described later.

Furthermore, a phytovalve 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 phytovalve 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 plunger body 5.
8, a vertical hole 73 of the servo piston body 57, and an m hole 72 of the conical valve body 56 to communicate with the supply fuel passage 71.

A feed valve 62 having small holes 69 and 69 is fitted into the phytovalve 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, this pump portion 55 has an oil passage 8 that directly communicates the fuel supply passage 71 with the nozzle spring seat insertion hole 40 of the injector cage 34.
6 is formed.

An oil passage 86 (Fig. 7) formed by a diagonal hole 81 of the conical valve body 56, a vertical hole 82 of the servo piston body 57, a diagonal hole 83 of the plunger body 58, and a diagonal hole 47 of the injector cage 34 is connected to the nozzle. The opening pressure of the valve 32 is determined by the mounting load of the nozzle spring 36 and the nozzle valve 32.
This oil passage 86 is determined by the sum of the back pressure of It is called a fuel passage 86.

Note that 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 bark.

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. Step 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 into the valve body 136 protruding downward from the lower end surface of the active core 112 with a lower spring 113 interposed between it and the active core 112. .

The static core 110 and active core 112 are
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 .

This core guide 109 is connected to the conical valve body 5.
The starting core 110 is fastened to the solenoid spacer 107 together with the flange of the starting core 110 by a lower support 115 screwed onto the starting core 110 .

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 hole 148 in the upper seat 119 is connected to the communication holes 147, 147, .
2 (FIG. 8) to the solenoid valve seat 10.
It is communicated with the through hole 144 of No. 6.

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 solenoid 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 positioned below the axial center of the active core 112 so that the active core 16 can be attracted and moved below the active core 112 when the active core 16 is excited.

Therefore, when the Tsuremade 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, the valve opening degree and valve stroke of the solenoid valve 111 can be adjusted as appropriate by rotating the upper seat 119 to change the relative position in the axial direction with respect to the solenoid valve 111.

In addition, 10.10a, 10b, 10c are fuel pipes for each cylinder in the case of a multi-cylinder engine, 117 is a yoke, and 120
121 is a lock nut for the upper seat 119; 122 is a pipe joint bolt; 124 is a coupling nut for integrally coupling the core guide 109 and the lower support 115;
．． Reference numerals 124a, 124b, and 124c indicate fuel return pipes for each air (7), and 126 indicates a connection terminal of the solenoid coil 116, respectively.

Next, the operation and action of the fuel injection device having a pump nozzle for an internal combustion engine according to the first embodiment of the present invention are illustrated in FIGS. 12 and 13 (simplified diagrams of the fuel injection device).
In this fuel injection device Z, a fuel supply pump 18 driven by an internal combustion engine Y supplies fuel in a fuel tank 19 to a pump nozzle X, and synchronizes with the rotation of the internal combustion engine Y. The solenoid valve 11 in the pump nozzle
1 is opened and closed 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. 111
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 the fuel oil flows out from the conical valve chamber 84, a pressure difference is generated before and after the conical valve 61, and the conical valve 61 is moved upward by the fuel pressure into the feed passage 71 and opens the inflow lower 7 of the servo piston chamber 76. speak.

When the servo piston chamber inflow lower 7 is opened, fuel oil is introduced into the servo piston chamber 76 into the feed passage 71 .

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.
opens, and the fuel in the plunger chamber 67 is sequentially injected into the working chamber 4 from the injection ports 49, 49, . . . through the high-pressure fuel passage 46.

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 biasing force of the spring 36 acting on the nozzle valve 36 and the pressure of the fuel oil flowing into the nozzle spring seat insertion hole 40 through the nozzle valve biasing fuel passage 86, and fuel injection ends. .

Next, referring to FIG. 13, the pump nozzle X when the solenoid coil 116 is de-energized 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 the fuel inlet 143 of the conical valve chamber 84 is opened. valve and close the fuel discharge port 149.

When the fuel inlet 143 is opened, fuel oil in the supply 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. The fuel tank 19 passes through the oil relief passage 94.
The hydraulic pressure inside the servo piston chamber 76 drops.

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

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 and further moves the plunger 59 and servo piston 60 upward to be filled.

By sequentially repeating the injection process shown in FIG. 12 and the filling process shown in FIG. 13, 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 and the return speed of the servo piston 60.

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 adjusted by appropriately restricting the outflowing fuel and changing the mounting load of the spring 64.

This pump nozzle
It is forced to flow inside.

Since the fuel is throttled, the rate of change in the opening area A of the inflow lower 7 with respect to the change in the valve lift of the conical valve 61 (that is, the descending speed of the servo piston 60) is the first.
As shown by the broken line in FIG. 1, the conical valve 61 changes stepwise from fully closed to fully open.

(Incidentally, when a conical valve 61 that does not protrude from the valve head as shown in FIG. 9B is used, the solid line is shown in FIG. 11.

(changes almost linearly).

The temporal change in the amount of fuel injected from the nozzle valve 32, that is, the fuel injection rate, is proportional to the descending speed of the servo piston 60.

By appropriately setting the shape and size of the protrusion 61a of the conical valve 61 and changing the opening area A of the inflow lower 7 by the protrusion 61a, the conical valve 6
The fuel injection rate at the initial stage of valve opening (i.e., the fuel injection rate during the pre-injection period) can be appropriately changed with respect to the fuel injection rate at full opening (i.e., the fuel injection rate at the main injection timing).

Furthermore, the dashed dot line L2 in FIG. 11 indicates the opening of the servo piston chamber inflow lower 7 with respect to the valve lift of the conical valve 61 when the second throttle portion 61a of the protrusion 61a is formed into a tapered shape as shown by the dashed line 61d' in FIG. Area A
The two-dot chain line L3 indicates the opening area A of the servo piston chamber inflow lower 7 when the second throttle portion 61d is formed so as to gradually become thicker toward the tip as shown by the chain line 61d'' in FIG. shows the state of change.

That is, by appropriately setting the shape of the second throttle portion 61d, it is possible to easily obtain a pump nozzle with a different transition pattern of the fuel injection rate during the pre-injection period without changing the specifications of other parts.

Next, the pump nozzle X of the second embodiment of the present invention shown in FIGS. 14 to 17 will be explained. The pump nozzle X of the second embodiment has a servo piston chamber inflow lower 7 as shown in FIG. The basic structure of opening and closing a conical valve 61 controlled by a solenoid valve 111 to drive a servo piston 60 and inject fuel at high pressure from the injection nozzle section 30 is the same as that of the first embodiment, except that Only the back pressure control method of the conical valve 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, by appropriately opening and closing the fuel outlet 155 of the conical valve chamber 84 with the solenoid valve 111, the back pressure of the conical valve 61 fitted in the conical valve chamber 84 is controlled, and the conical valve is closed according to the control pressure. 6
The conical valve 61 opens and closes the servo piston chamber inflow lower 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 port 148 of 33.

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 moved downward by the spring force of the spring 132 as shown in FIG. It is pushed down and the fuel discharge port 155 of the conical valve chamber 84 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 61 is moved downward by the spring 65 and acts to close the servo piston chamber inflow lower 7.

In addition, the servo zeston 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. 14, reference numeral 130 indicates a core guide;
Reference numeral 3 indicates a static core, and all other members correspond to the members shown in FIG. 2 of the first embodiment, so please refer to the description of the first embodiment.

In the pump nozzle X shown in the first and second embodiments, since the servo zeston chamber inflow lower 7 is opened and closed by the conical valve 61, the diameter of the servo zeston chamber inflow lower 7 can be made large; Moreover, the valve seat 79 of the conical valve 61 is 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 the suction ability from decreasing due to a rise in temperature of the coil 116, and the solenoid valve 111 can be operated more reliably.

Next, to explain the effects of the pump nozzle for internal combustion engines of the present invention, the pump nozzle for internal combustion engines of the present invention is a solenoid valve that is driven to open and close by a Tsuremade coil, and the back pressure of the Konica valve that controls the operation of the servo piston. Since the valve seat area of the Tsuremade valve can be reduced and a solenoid with a small suction load can be used, the solenoid part can be made smaller and lighter.

Furthermore, the fuel injection rate during the pre-injection period and the fuel injection rate during the main injection period can be adjusted by appropriately changing the passage area for fuel flowing into the servo piston chamber with a protrusion formed on the valve head of the conical valve. can be set to the optimum value, the fuel characteristics of the internal combustion engine can be improved to the extent that the amount of fuel injected during the ignition delay period, that is, at the beginning of fuel injection, is reduced and troubles such as knocking are less likely to occur. There is an effect.

In addition, by providing a protrusion on the valve head of the unical valve, it is possible to automatically control the fuel injection rate during the pre-injection period and the fuel injection rate during the main injection period. There is no need to specially provide a nozzle for pre-injection, and the structure of the nozzle part can be simplified.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of main parts of an internal combustion engine equipped with an injection device having a pump nozzle according to an embodiment of the present invention, Fig. 2 is a longitudinal sectional view of the pump nozzle shown in Fig. ■ of the diagram
Figure 4 is an enlarged view of the ■ part of Figure 2, Figure 5 is an enlarged view of the
Figure 6 is a cross-sectional view of main parts along line ■-V in the figure, Figure 6 is a view in the direction of the ■ arrow in Figure 5
Figure 7 is a vertical cross-sectional view of Figure 6, and Figure 8 is a vertical cross-sectional view of Figure 3.
-■ Cross-sectional view, Fig. 9A is a structural explanatory diagram of the conical valve shown in Fig. 2, Fig. 9B is a structural explanatory diagram of a conical valve other than the present invention, Fig. 10 is a structural explanatory diagram of the conical valve shown in Fig. 9A. A detailed view of the valve head in the valve, Figure 11 is a diagram showing the change in the opening area of the servo piston chamber inlet with respect to the lift of the conical valve, and Figures 12 and 13 are the operation of the pump nozzle in Figure 2. Explanatory drawings, FIG. 14 is a vertical sectional view of a pump nozzle of a fuel injection device according to a second embodiment of the present invention, and FIG.
The enlarged view of the XV section in the figure, and FIGS. 16 and 17 are explanatory views of the operation of the pump nozzle shown in FIG. 14. 32... Nozzle valve, 49... Spout, 59... Plunger, 60... Servo piston, 61...000 Conical valve, 61
a = protrusion, 61e--valve head, 62...
・Feed valve, 67...Plunger chamber, 7
1... Fuel inlet, 76... Servo piston chamber, 77... Servo piston chamber inlet, 8
4... Conical valve chamber, 87... Servo piston chamber outlet, 111... Solenoid valve, 16... Solenoid coil.

Claims (1)

[Scope of utility model registration request] The fuel oil supplied from the lower fuel hole 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 for discharging the supplied fuel from the servo piston chamber 76. 87, and a conical valve 61 for opening and closing the servo piston chamber inflow lower 7 is arranged opposite to the servo piston chamber inflow lower 7 to introduce fuel oil into the conical valve chamber 84 housing the conical valve 61. The discharge causes the conical valve 61 to close or open the servo diesel chamber inflow lower 7, and an electric signal is transmitted in synchronization with the rotation of the engine to introduce and discharge fuel into the conical valve chamber 84. The internal combustion engine is controlled by a solenoid valve 111 driven by a solenoid coil 116 whose excitation is controlled by The valve head 61 of the conical valve 61 is a pump nozzle for
(a) is provided with a protrusion 61a that can appropriately change the opening area of the servo piston chamber inflow lower 7 while the conical valve 61 is displaced from its closed state to the maximum lift. Pump nozzle for internal combustion engines.