JPH01159458A - Fuel injection system for internal combustion engine - Google Patents

Abstract

PURPOSE:To make high pressure fuel feedable with a simple device by constituting a pressure intensifying means to generate pressure conformed to the area ratio of a piston, in such a device that feeds a fuel injection valve with fuel out of a fuel feeding means under pressure after being boosted by the pressure intensifying means. CONSTITUTION:Fuel discharged out of a fuel pump 1 being driven by an engine is fed to a pressure intensifying device 17 by a passage 11, or a passage 15 with a check valve 13, and this pressure intensifying device 17 is connected to a fuel injection nozzle 23 via a passage 21 where a check valve 19 is installed. This pressure intensifying device 17 is made up of fitting a piston 43, connecting a large diametral part 37 and a small diametral part 39 through a connecting part 41, in different diametral fitting holes 33, 35 of a valve body 31 free of sliding motion, and these passages 15, 21 are connected to a fuel pressure-feed chamber 45. In addition, a spool 61 is inserted into the large diametral fitting hole 33 free of floating motion, and this spool 61 is pressed and moved by the piston 43 whereby passages 53, 57 being interconnected each to a pressurized chamber 47 and a tank 3 are interconnecting or interrupted in an alternative way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fuel injection device for a diesel engine or the like, and more particularly to a mechanism for supplying high-pressure fuel.

[Prior Art] Conventionally, a size-type fuel injection pump is known as a fuel injection pump suitable for large-sized diesel engines. This pump has the same number of plungers as the number of cylinders lined up in a row, and a camshaft moves the plungers up and down to pump fuel.

[Problems to be Solved by the Invention] Incidentally, as a measure to purify exhaust gas from a diesel engine, it has been desired to increase the pressure of fuel from a fuel injection pump.

However, in the conventional fuel injection pump described above, in order to achieve high pressure, the device itself must be enlarged, which causes problems in mounting it on a vehicle and increased costs.

The present invention as claimed in claim 1 has been made to solve the problems of the prior art described above, and an object thereof is to provide a fuel injection device for an internal combustion engine that can supply high-pressure fuel with a small and simple configuration. .

Furthermore, in addition to the object of claim 1, it is an object of the invention of claim 2 to provide a fuel injection device for an internal combustion engine that improves engine starting performance and the like.

[Means for Solving the Problems] The invention of claim 1 made to solve the above problems comprises: a fuel supply means for discharging fuel; a pressure increase means for increasing the pressure of the fuel from the fuel supply means; A fuel injection device for an internal combustion engine, comprising: a fuel injection valve that injects fuel pressurized by a pressure increaser into the internal combustion engine; a formed valve body; a piston having a large diameter portion and a small diameter portion that are slidably fitted into the large diameter fitting hole and the small diameter fitting hole, respectively; and a part of the small diameter fitting hole; formed by the end face of the small diameter part,
a fuel feeding chamber that is supplied with fuel from the fuel supply means and is connected to the fuel injection valve; a pressurized chamber that is formed by a part of the large diameter fitting hole and an end surface of the large diameter portion; a first passage that communicates between the fuel supply means and the pressurizing chamber; a second passage that communicates the pressurizing chamber and the drain; and a second passage that is slidably fitted into the large-diameter fitting hole; A spool that selectively connects and blocks the first and second passages by moving under pressure from the piston.

Furthermore, the invention of claim 2 provides a switching means for selectively switching between supplying fuel from the fuel supply means to the passage communicating with the pressurizing chamber of the pressure increase means and supplying fuel from the fuel supply means to the fuel injection valve. The gist of this paper is a fuel injection ITi system for an internal combustion engine.

Here, the fuel supply means refers to, for example, a fuel pump or the like driven by the driving force of an internal combustion engine, a motor, or the like.

Furthermore, the fuel injection valve injects high-pressure fuel from the pressure increase means into the cylinder of the internal combustion engine, and as a means for controlling the injection timing and injection amount of the fuel, for example, a control signal is sent from an electronic control device. A device that opens and closes a solenoid valve by using the driving force of an internal combustion engine, and a device that opens and closes a valve by driving a cam using the driving force of an internal combustion engine can be applied.

[Function] The fuel supply means in the present invention described in claim 1,
Fuel is discharged by the driving force of an engine or the like, and this fuel is added to the pressure increasing means. In the pressure increasing means, a piston consisting of a large diameter part and a small diameter part is slidably fitted in the fitting hole, and a pressurizing chamber formed by the large diameter part and the fitting hole is fitted. When fuel is supplied through the first passage, a fuel pressure proportional to the pressure receiving area of the large diameter part and the small diameter part is generated in the fuel feeding chamber formed by the small diameter part and the fitting hole. Therefore, high-pressure fuel is pumped from the fuel pumping chamber to the fuel injection means.

Then, when the fuel is sent out from the fuel pumping chamber and the piston moves, the spool in the fitting hole moves together with the piston, blocking the first passage from the pressurizing chamber and opening the second passage to the atmosphere. open to As a result, the fuel in the pressurizing chamber is discharged and, at the same time, the fuel pumping chamber is replenished with fuel. By repeating this state, the pressure increasing means receives fuel supply and also performs pressure feeding of fuel.

That is, the wood pressure increase means controls the communication cutoff of the passage to the pressurizing chamber and the fuel pumping chamber by moving the spool, and
By supplying and discharging fuel to and from both chambers, high-pressure fuel proportional to the pressure-receiving area of both end surfaces of the piston is pumped.

Further, the invention described in claim 2 provides the following effects since a switching means is provided in addition to the effect of claim 10. That is, by the switching operation of this switching means, it is possible to selectively set the supply of fuel to the pressurizing chamber of the pressure increasing means and the supply of fuel to the fuel injection valve. When starting the engine, the supply of fuel to the pressure increase means that increases the load on the engine can be stopped, and fuel can be supplied directly from the fuel pump to the fuel injection valve.

[Example] An example of the present invention will be described below with reference to the drawings. FIG. 1 is a hydraulic circuit diagram showing the configuration of a fuel injection device for a diesel engine. In FIG. 1, reference numeral 1 denotes a fuel pump that is connected to the engine via an electromagnetic clutch or the like and is driven by its driving force. Then, this fuel is sent under pressure to a pressure increase device (pressure increase means) 17 through a passage 9 having a filter 7, and further through a passage 15 having a branched passage 11 and a check valve 13. The pressure increase device 17 is connected via a passage 21 provided with a check valve 19.
Injection nozzle 23 that injects fuel into a cylinder (not shown)
It is connected to the. This injection nozzle 23 further drains into the fuel tank 3 via a passage 25 .

The pressure increase device 17 includes a valve main body 31, and a large diameter fitting hole 33 and a small diameter fitting hole 35 are bored in the valve main body 31. The large-diameter fitting hole 33 and the small-diameter fitting hole 35 have a large-diameter portion 37 and a small-diameter portion 39 connected to the connecting portion 4.
A piston 43 connected at 1 is slidably fitted. A chamber surrounded by a part of the small-diameter fitting hole 35 and the end surface of the small-diameter portion 39 serves as a fuel pressure-feeding chamber 45.
This fuel delivery chamber 45 communicates with the above-mentioned passage 15.21. On the other hand, a chamber surrounded by a part of the large-diameter fitting hole 33 and the end face of the large-diameter portion 37 is a pressurization chamber 47, and this pressurization chamber 47 is connected to the first operation boat 49. aisle 53
It communicates with the second actuating boat 51 on the side wall of the large-diameter fitting hole 33 through. Further, a pressure boat 55 of the passage 11 communicating with the fuel pump 1 is formed on the side wall of the large diameter fitting hole 33, and a pressure boat 55 of the passage 11 communicating with the fuel pump 1 is formed on the wall surface facing the pressure boat 55, communicating with the fuel tank 3. A discharge boat 59 of the passage 57 is formed.

A spool 61 is slidably fitted into the large-diameter fitting hole 33, and a through hole 63 is formed in the center of the spool 61.
The connecting portion 41 of No. 3 passes through, and the through hole 63 and the connecting portion 4
1 is slidable. An annular groove 65 is formed in the side of the spool 61, which is narrow at one end and wide at the other end.

The injection nozzle 23 is provided in the valve body 71,
This valve body 71 includes a fitting hole 73 and a nozzle fuel reservoir 75.
A nozzle hole 77 is provided therein so as to communicate with each other, and a needle 79 is slidably fitted into the fitting hole 73. A liquid chamber 81 is formed in the area surrounded by the upper side of the fitting hole 73 and the needle 79, and in this liquid chamber 81, an orifice 83 and a reverse ratio valve 85, which are connected in parallel to each other, and a 30,000 solenoid valve 87 are formed. is connected. This injection nozzle 23 communicates with the passage 21 that communicates with the pressure booster 17 through a nozzle fuel reservoir 75 through a passage 91, and also through one boat of a three-way solenoid valve 87. 3 more
Another boat of the solenoid valve 87 is connected to the fuel tank 3 through the passage 25.

In addition, in the above configuration, in order to match the fuel discharge amount from the fuel pump 1 with the fuel injected from the injection nozzle 23, the fuel pump is configured to include a pressure sensor 91 that detects the fuel pressure in the passage 11 and an electronic control device 93. A control mechanism 95 is provided.

Next, the operation of the above configuration will be explained.

The fuel pumped from the fuel tank 3 by the fuel pump 1 passes through the filter 7 to the pressure boat 5 of the pressure booster 17.
5. Now, when the spool 61 is in the position shown in FIG. is supplied to The piston 43 is pressed and moved in the direction of the arrow a by the fuel pressure supplied to the pressurizing chamber 47. At this time, the hydraulic pressure of the fuel in the fuel feeding chamber 45 on the other end surface of the piston 43 becomes a value proportional to the ratio of the pressure receiving area of the end surface of the large diameter portion 37 of the piston 43 to the pressure receiving area of the end surface of the small diameter portion 39. .

For example, when the pressure receiving area ratio of both end faces of the piston 43 is 5, when fuel is supplied from the fuel pump 1 at a pressure of 200 kg/cm2, the pressure of 1000 kg/cm2 is supplied from the fuel pumping chamber 45.
It becomes high pressure of g/cm2 and is forcedly fed to the injection nozzle 23.

Then, fuel is supplied to the pressurizing chamber 47, and the fuel feeding chamber 4
5 to the injection nozzle 23,
When the piston 43 further moves in the direction of the arrow a (FIG. 2), the piston 43 contacts and presses the lower surface of the spool 61, and the spool 61 moves to the position shown in FIG. 3. As a result, the pressure boat 55 is
At the same time, the second working boat 51 and the discharge boat 59 are connected via the annular groove 65. At the position of this spool 61, the pressurizing chamber 47 communicates with the passage 53 → the annular ring 65 → the passage 57 and is opened to the atmosphere.
of fuel is returned to the fuel tank 3.

In this state, the hydraulic pressure in the fuel pumping chamber 45 decreases, so
Since the check valve 19 (FIG. 1) is closed and the pressure boat 55 is closed, fuel from the fuel pump 1 is supplied to the fuel pumping chamber 45 via the check valve 13. As a result, the piston 43 moves in the direction of the arrow. Then, as shown in FIG. 4, fuel is sufficiently supplied to the fuel feeding chamber 45 and the spool 61 reaches the end surface of the small diameter portion 39 of the piston 43.
When the is pressed and moved, the discharge boat 59 is closed on the side of the spool 61, and the pressure boat 55 and the second working boat 5 are
1 and return to the state shown in FIG.

By repeating such operations, high-pressure fuel is supplied from the pressure booster 17 to the injection nozzle 23.

Next, to explain the operation of controlling the output of the fuel pump 1, a detection signal from the pressure sensor 91 provided in the passage 11 connected to the fuel pump 1 is input to the electronic control device 93, and based on this pressure signal, The output of the fuel pump 1 is controlled to be increased or decreased by using an electromagnetic clutch or the like. In other words, when the amount of fuel injected from the injection nozzle 1 is small, the passage 11.1
5, the pressure sensor 91 detects this and the electronic control unit 93 suppresses the output of the fuel pump 1. Conversely, when the fuel injection amount is large, the pressure in the passage 11.15 increases.
As the internal pressure decreases, the output of the fuel pump 1 is increased.

Next, the operation of the injection valve nozzle 23 will be explained.

Now, as shown in the figure, when the three-way solenoid valve 87 is switched from the state in which the needle 79 closes the nozzle hole 77 to communicate the liquid chamber 81 with the drain side passage 25 (flow direction indicated by ■), the nozzle opens. A force in the valve opening direction acts on the needle 79 which receives the hydraulic pressure in the fuel reservoir 75, so that the fuel in the liquid chamber 81 is discharged through the orifice 83, the nozzle hole 77 is opened, and fuel is injected. Next, when the three-way solenoid valve 87 is switched so as to communicate the passage 21 side and the liquid chamber 81 (flow direction indicated by ■), the high-pressure fuel in the pressure booster 17 flows through the check valve 85 and the orifice 83. The fuel is supplied to the liquid chamber 81 and presses the needle 79 to close the nozzle hole 77 and stop fuel injection. In this way, by switching the opening and closing of the three-way solenoid valve 87, the fuel injection amount and fuel injection timing are controlled. Note that in this injection nozzle 23, the fuel in the liquid chamber 81 flows out through the orifice 83 in the flow direction of the three-way solenoid valve 87, whereas the fuel from the passage 21 flows out through the orifice in the flow direction of the three-way solenoid valve 87. The liquid flows into the liquid chamber 81 not only through the check valve 83 but also through the check valve 85. Therefore, since the valve opens slowly in the flow direction (①) and quickly closes in the flow direction (②), the orifice 83 controls the rate of change in fuel injection over time (injection rate). This can be done by adjusting the flow rate.

Therefore, according to the pressure increase device 17 of the above embodiment, since a device that generates a pressure according to the pressure receiving area ratio of the piston 43 is used, it is not complicated like the size-type fuel injection pump described in the related art. High-pressure fuel can be supplied with a simple configuration without increasing the size.

In addition, the pressure booster 17 can easily change the amount of fuel injected by connecting to the injection nozzle 23 and controlling the opening and closing of the injection nozzle 23.

FIG. 5 shows another embodiment, in which the main components (pressure increase device, etc.) are the same as those in the embodiment shown in FIG. , with some parts replaced with other devices.

(2) Among the passages branching from the passage of the fuel pump 1, a reverse valve 101 is provided in the passage connected to the pressure boat 55 of the pressure booster 17. The opening pressure of this check valve 101 is set higher than the opening pressure of the check valve 13 provided in the other branched passage 15. Therefore, when supplying fuel to the fuel pumping chamber 45 with the spool 61 in the position where the pressure boat 55 is closed, the check valve 13 opens before the check valve 101 reaches the opening pressure and the fuel pumping chamber 45 is supplied with fuel. Fuel is supplied.

Therefore, even if the seal to the pressure boat 55 is insufficient at the position where the spool 61 closes the pressure boat 55, or even if the pressure boat 55 is not completely closed, fuel will not be supplied to the pressure boat 55. The fuel from the fuel pump 1 is drained through the annular structure 65, thereby preventing fuel leakage.

(2) An accumulator 103 is provided in a passage that communicates the pressure booster 17 and the injection nozzle 23A. By using the accumulator 103, it is possible to suppress fluctuations in fuel pressure caused by the reciprocating movement of the piston 43 from the pressure booster 17.

Furthermore, in order to suppress the increase and decrease of fuel, the effect can be further increased by configuring a damper device 105 using a spring integrally with the accumulator 103, as shown in FIG. Note that the damper device may be formed separately from the accumulator and provided anywhere in the passage 21.

(2) Instead of the injection nozzle 23 controlling fuel injection by switching a three-way solenoid valve 87, the needle 79 is moved up and down by a cam 107 linked to the engine crankshaft.

FIG. 7 shows yet another embodiment. In the above-mentioned embodiment, the fuel is pumped by moving only one side of the piston 43, but in this embodiment, the fuel is pumped by the reciprocating movement of the piston. That is, on both sides of the large-diameter fitting hole 33 formed in the valve body 31, there are small-diameter fitting holes 35A.
, 35B are connected to each other, and the fitting hole 33 has large diameter portions 37A, 37B connected to both sides of the connecting portion 42 constituting the piston 43.
Small diameter portions 39A and 39B are slidably fitted in the respective portions. A fuel pumping chamber 4 is provided in a chamber surrounded by the fitting holes 45A, 45B and the end faces of the small diameter portions 39A, 39B.
5A and 45B are formed. This fuel pumping chamber 45A
, 45B are connected to the fuel pump (see Figure 1);
and passages 15A and 15B having check valves 13A and 13B.
It also communicates with passages 21A and 21B having check valves 19A and 19B. In addition, the large diameter fitting hole 33, the large diameter portions 37A, 37B, and the small diameter portions 39A, 3
The chambers surrounded by 9B are pressurizing chambers 47A, 47B, and the first operating bows 49A, 49B on one end surface of the pressurizing chambers 47A, 47B and the first operating bows 49A, 49B on the side wall of the large-diameter fitting hole 33 The two working boats 51A, 51B are in communication via passages 53A, 53B. Further, pressure boats 55A and 55B of passages 11A and IIB communicating with the fuel pump are formed in the side wall of the large diameter fitting hole 33, and pressure boats 55A and 55B are formed in the side wall of the large diameter fitting hole 33.
On the wall facing 5A, 5'5B, there are discharge holes 59A, 59 of passages 57A, 57B communicating with the fuel tank 3.
9B is formed.

A spool 61A is slidably fitted into the large-diameter fitting hole 33, and a through hole 63 is formed in the center of the spool 61A. The connecting portion 42 passes through the through hole 63 and the connecting portion 42 is slidable. The wound part of this spool 61A has an annular groove 6 which is narrow at one end and wide at the other end.
5A and 65B are formed in parallel at a distance of 2 m.

The operation of this embodiment is almost the same as that of the pressure booster shown in FIG. 1, except that the fuel is pumped by the reciprocating movement of the piston 43. That is, at the illustrated spool A position, the fuel from the fuel pump is pumped from the pressure cap () 65B to the annular groove 6.
5B→second working boat 51B→passage 53B→first working boat 49B to be supplied to pressurizing chamber 47B. On the other hand, the pressurizing chamber 47A is connected to the first working boat 49A → the passage 53A → the second
The fuel in the pressurizing chamber 45A is discharged into the fuel tank 3 through communication from the operating boat 59A to the annular groove 69A to the passage 57A.

Therefore, fuel is supplied to the pressurizing chamber 47B, and the pressurizing chamber 4
Since fuel is drained from 7A, the piston 43 moves in the direction of the arrow a. Thereby, fuel is forced to be fed from the fuel feeding chamber 45A to the injection nozzle.

Then, when the piston 43 moves in the direction of arrow a and presses the lower surface of the spool 61A, the spool 6
1A moves. As a result, the pressure capo 55B is closed on the side surface of the spool 61A, and at the same time, the second operating boat 53B and the discharge boat 59B are connected via the annular groove 65B. The second operating boat 59A, the passage 53A, and the first
It communicates with the operating boat 49A. Therefore, the pressurizing chamber 47
At the same time that fuel is supplied to A, the fuel in the pressurizing chamber 47B is discharged, so that, contrary to the above, the piston 43 moves in the direction of the arrow, and fuel is force-fed from the fuel pumping chamber 45B.

Therefore, according to the above embodiment, when the piston 43 is moving in the direction of the arrow a, from the fuel pumping chamber 45A,
On the other hand, when moving in the direction of the arrow, the fuel pumping chamber 4513
Since fuel is fed under pressure from each of the pistons 43 and 43, fuel can be continuously supplied by the reciprocating movement of the piston 43.

Next, an embodiment in which the starting performance of the engine is improved will be described using FIG. 8.

In the figure, a passage 11 that supplies fuel discharged from the fuel pump 1 to a pressure boat 55 of a pressure booster 17 is provided with a cut valve 2 (switching means) as an electromagnetic valve that can be switched to a communicating/blocking position. ing. This cut valve 2 is
It is switched by operating the ignition switch 4,
That is, when the starter is in the ON position of the ignition switch 4, the ignition switch 4 moves in the direction of ■ to the cutoff position, and when the starter is in the OFF position, it moves in the direction of ■ to switch to the communication position (the state shown in the figure). By adding such a configuration, when the ignition switch 4 is turned to the starter ON position to start cranking when starting the engine, the fuel pump 1 draws up fuel from the fuel tank 3, pressurizes it, and discharges it. At this time, the cut valve 2 that has received the starter ON signal from the ignition switch 4 has been switched to the cutoff position, so the low pressure fuel from the fuel pump 1 is not supplied to the pressure boat 55 and is The fuel is supplied to the pressure feeding chamber 15 of the pressure increase device 17 through the valve 13 to prepare for the start of pressure increase, and the check valve 19 and the passage 21
Fuel is also supplied to the injection nozzle 23 via. Then, when a control signal is manually applied to the three-way solenoid valve 87 of the injection nozzle 23, fuel injection is performed by the operation described above. - On the other hand, when the engine starts and the ignition switch 4 is returned to the starter OFF position, the cut valve 2 is switched in the direction of the arrow ■, and the pressure boat 55 of the pressure booster 17 is
Fuel supply to begins. Therefore, fuel pressure increase as described in the embodiment of FIG. 1 is started.

The addition of such a cut valve 2 provides the following effects. That is, in the apparatus of the embodiment shown in FIG. 1, fuel is supplied to the pressure booster 17 from the time of startup;
In some cases, the load on the fuel pump 1 and the load on the starter become large in order to supply enough fuel to drive the fuel pump 7.

However, in this embodiment, during startup, fuel is not supplied from the fuel pump to the pressure booster 17 but directly to the fuel injection nozzle 23 . Therefore, fuel having sufficient pressure to start the engine can be injected by supplying it from the fuel pump 1, improving the starting performance of the engine, and further reducing the load on the starter and reducing power consumption. is possible.

FIG. 9 shows a modification of the embodiment shown in FIG. 8, in which the cut valve 2 is switched and controlled by an electronic fall device 93, and for example, the engine speed, throttle valve opening, etc. are used as parameters. The fuel supply to the pressure booster 17 may be optionally bypassed not only at the time of starting but also when a low injection pressure is sufficient.

In addition, as shown in FIG. 10, the fuel injection nozzle 23 has
Using an electromechanical transducer 120 such as a piezo element or a magnetostrictive element as described in JP-A-61-118528, the needle 79A is raised and lowered by expansion and contraction to control the fuel injection timing and injection rate. You can.

In addition, in the fuel injection device of the above embodiment, the cut valve 2
It goes without saying that the installation or non-installation of the accumulator 103 (FIG. 6), the control method of the cut valve 3, and the type of the injection nozzle 23 can be appropriately combined depending on the application.

[Effects of the Invention] As explained above, according to the invention of claim 1, the pressure increase means that generates the pressure according to the area ratio of the piston is used, so that the size-shaped fuel injection explained in the conventional technology is not possible. High-pressure fuel can be supplied with a simple configuration without the need for complex and large pumps.

Further, according to the invention of claim 2, in addition to the effect of the invention of claim 1, when the engine is started, by the action of the switching means, the pressure necessary and sufficient for starting is increased without going through the pressure increase means. Pressurized fuel can be injected from the fuel injection valve, making it possible to improve engine starting performance, reduce the load on the starter, and reduce power consumption.

[Brief explanation of the drawing]

FIG. 1 is a hydraulic circuit diagram showing a fuel injection device for a diesel engine according to an embodiment of the present invention, FIGS. 2 to 4 are explanatory diagrams explaining the operation of the pressure booster of the same embodiment, and FIG. A hydraulic circuit diagram showing a fuel injection device of another embodiment, FIG. 6 is a block diagram showing a damper device, FIG. 7 is a block diagram showing a pressure booster of another embodiment, and FIG. 8 is a block diagram showing a cut valve. 9 and 10 are hydraulic circuit diagrams showing a modification of FIG. 8. 1... Fuel pump (fuel supply means) 2... Cut valve (switching means) 4... Ignition switch 17... Pressure increase device (pressure increase means) 13.19... Check valve 23. ...Injection nozzle (fuel injection valve) 31...Valve body 33...Large diameter fitting hole 35...
・Small diameter fitting hole 37...Large diameter part 39...Small diameter part 43...Piston 45...Fuel pressure feeding chamber 47
... Pressure chamber 53 ... Passage (first passage) 57 ... Passage (second passage) 61 ... Spool agent Patent attorney Tsutomu Sadachi (and one other person) Figure 2 Drawing No. 2 Figure 3 Figure 4 Figure 6

Claims (1)

[Scope of Claims] 1. A fuel supply means for discharging fuel, a pressure increase means for increasing the pressure of the fuel from the fuel supply means, and a fuel injection valve for injecting the fuel increased in pressure by the pressure increase means into an internal combustion engine. In the fuel injection device for an internal combustion engine, the pressure increasing means includes a valve body having a large diameter fitting hole and a small diameter fitting hole, and a valve body having a large diameter fitting hole and a small diameter fitting hole. a piston having a large diameter part and a small diameter part that are slidably fitted into the holes, a part of the small diameter fitting hole and an end face of the small diameter part,
a fuel feeding chamber that is supplied with fuel from the fuel supply means and is connected to the fuel injection valve; a pressurized chamber that is formed by a part of the large diameter fitting hole and an end surface of the large diameter portion; a first passage communicating between the fuel supply means and the pressurizing chamber, a second passage communicating between the pressurizing chamber and the drain, and slidably fitted into the large diameter fitting hole; A fuel injection device for an internal combustion engine, comprising: a spool that selectively communicates and blocks the first and second passages by moving under pressure from the piston. 2. The fuel injection device for an internal combustion engine according to claim 1, wherein the fuel supply from the fuel supply means to the passage communicating with the pressurizing chamber of the pressure increase means and the fuel supply from the fuel supply means to the fuel injection valve are selective. A fuel injection device for an internal combustion engine, characterized in that it is provided with a switching means for switching.