JPS6026159A - Fuel injection controller - Google Patents

Abstract

PURPOSE:To improve the dynamic characteristics without increasing the driving electromagnetic force by installing a flow guide at a specific position in a fuel feeding passage on the upstream of a seat part, in the fuel injection controller of a Diesel engine. CONSTITUTION:The solenoid valve 40 of a fuel injection controller is installed between fuel feeding passages 8a and 8b. A flow guide 81 is installed, at the position opposed and departed from the opened-port part of a pressure balance passage, into a fuel feeding passage 55 on the upstream of the seat part at the heat part of a valve body 43. The combustion pressure close to the max. value acts in the direction of opening valve at the head part of the valve body, while a lower combustion pressure acts into a back-pressure chamber 72 through the pressure balance passage, and this pressure acts onto the valve body in the direction of closing valve. Therefore, the dynamic characteristics of the solenoid valve can be improved without increasing the driving electromagnetic force.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel injection control device for a unit injector used in a diesel engine.

Diesel engines usually use an injection engine that increases the pressure of the fuel to perform fuel injection. A unit injector is a unit injector that integrates these components into one unit, a fuel injection pipe that supplies fuel to all nozzles that is fed under pressure from this injection pump, and a nozzle that injects high-pressure fuel. This eliminates the need for a long fuel injection pipe, so the injection delay is small, and the volume to be compressed becomes smaller by the amount of the missing fuel injection pipe, resulting in higher injection pressure and better atomization of the fuel. In addition, it has other advantages such as being able to increase the injection rate and having less fuel lag at the end of injection.

Such a fuel injection device disposed in all cylinders of a unit injector is disclosed in, for example, Japanese Patent Laid-Open No. 54-50726 (US Pat. No. 4,129,253).
This is shown in Figures 1 and 2.

In FIG. 1.2, a plunger 4a is slidably inserted into a cylinder 3 bored in the main body 2 of the unit injector 1, and this plunger 4a is connected to a syringer 4b.

The plunger 4b is biased upward in the figure by a spring 6 interposed between its head and the main body 2, and a cam (not shown) rotating in synchronization with the machine PA is attached to the head of the plunger 4b. Since the plunger 4b is pressed down by one rotation of the cam when it comes into contact with the cam from above, the syringer 4a connected to the plunger 4b moves up and down.

The pressure chamber 7 of the cylinder 3, which is formed facing one end of the syringe 4a, is connected to a fuel tank (not shown) through a fuel supply passage 8.
A, 8bk communicate with each other, and a low-pressure fuel supply cylinder f (not shown), which rotates with the machine ryIK cycle, supplies fuel to the fuel kH-force chamber 7 in the fuel tank.

A nozzle 10 is formed in the lower part of the main body 2 to inject fuel in the pressure chamber 7, which is pressurized by the downward movement of the plunger 4a, into a combustion chamber (not shown). Specifically, the nozzle 10 includes a needle chamber 11 communicating with the pressure chamber 7 via a fuel passage 9, a needle valve 12, a spring 13, and a nozzle hole 14.
, a spring guide 15, and a spring chamber 16. Normally, the spring 13 urges the needle valve 12 downward via the spring guide 15' to close the nozzle hole 14, but the fuel in the pressure chamber 7 The fuel in the needle chamber 11 is sent to the needle chamber 11 via the passage 9, and when the pressure in the needle chamber 11 overcomes the spring 13, the needle valve 12 is urged completely upward to open the nozzle hole 14, and the fuel in the needle chamber 11 flows into the nozzle hole 14. It is designed to be sprayed from Therefore, the valve opening pressure of the spring 13e (-) is set.

A solenoid valve 18 as a valve device is installed in the fuel supply passages 8a and 8b communicating with the pressure chamber 7.
In this case, the cylinder 20 provided in the valve holder 19 is fully moved and the valve body 21 is urged by the spring 22 to open the valve, and when the drive current is applied to the solenoid 24,
Due to the electromagnetic force of the solenoid 24, the armature 26 resists the spring 2217C and seats the valve body 21 in the valve closing direction (-J force).

When the solenoid valve 18 is opened, the fuel in the pressure chamber 7, which becomes high pressure due to the descent of the plunger 4a, escapes from the fuel supply passage 8alC via the 714 if valve 18, but the orifice 17 regulates the fuel flow M at this time. By doing so, the total fuel pressure in the pressure chambers 72 and passages 8b and 9 is maintained at a predetermined value p smaller than the valve opening pressure of the nozzle 10.

A control circuit (not shown) that controls the drive current to the solenoid valve 18 includes means for detecting all engine operating conditions (for example, an engine rotation speed sensor, an accelerator sensor that detects the depression angle of the accelerator pedal, and a cooling water temperature of the machine IM+). Based on the detection signals from the water temperature sensor, which detects the entire crank angle, and the crank angle sensor, which detects the entire crank angle, the signal is output to all solenoids 24, which have the optimum drive and rotation width for the engine operating condition, and controls the full opening and closing of the solenoid valve 18. .

The fuel relief passage 28a communicating with the spring chamber 16 and the fuel relief passage 28b communicating with the annular groove 29 formed in the upper part of the cylinder merge and then communicate with the fuel supply passage 8a upstream of the valves 18. , the excess fuel is returned to the entire passage 8a.

Therefore, when the fuel in the fuel tank prepressurized by the fuel supply pump is supplied from the fuel supply passage 8a to the pressure chamber 7 via the solenoid valve 18 (open), it rotates in synchronization with the engine. The cylinder/jar 4a is lowered by the cam that moves to the pressure chamber 7.
The fuel starts to be fully pressurized, but at this point the tri solenoid valve 18
is open, so some of the pressurized fuel flows into the solenoid valve 18.
The fuel flow is completely regulated by the orifice 17, and the fuel pressure in the pressure chamber 7 and the passages 8a and 9 exceeds a predetermined value (11).
．． I can't reach L.

When the solenoid 24 is energized and the electromagnetic valve 18 is closed during the descent of the plunger 4a, the fuel in the pressure chamber 7 is trapped and the fuel pressure is fully increased, and this fuel pressure reaches the needle R[ill] via the fuel passage 9. The fuel pressure in the needle chamber 11 is the force that urges the spring 13 downward (the valve opening pressure of the nozzle 10).
Immediately, the needle pulp 12 is pushed upward to the nozzle hole 14, and the light in the needle chamber 11 is injected into a combustion chamber (not shown).

When the solenoid 24 is no longer energized at a predetermined crank angle and the solenoid valve 18 is opened, part of the fuel in the pressure chamber 7 escapes to the fuel supply passage 8a via the solenoid valve 18 as described above. The fuel pressure in the needle chamber 11 quickly decreases to below the valve opening pressure of the nozzle 1o, and 11r ends.

That is, fuel injection is performed while the solenoid valve 18 is closed, and by changing the timing and duration of energization to the solenoid 24 that opens and closes the Tf magnetic dual valve 8, depending on the operating state, The injection timing and injection amount of fuel injected from the nozzle 10 are optimally controlled. .

By the way, the maximum lift 3 of the solenoid valve 18 is -*Sl 1c from the gap lit Vc between the armature and the core.
The leak orifice formed between the valve body 21 of the VC valve 18 and the valve seat should be sized to withstand this large lift. fff
If the maximum lift is small, the drop in injection pressure at the end of injection will be slow and the injection will be poor.

In order to increase the leak orifice area, VC can be considered by increasing the seat diameter of the valve body or by increasing the diameter of the valve body. In the former case where the seat diameter is increased, the valve body is fully seated according to the state of the seat diameter 14j,
For example, when the injection pressure is set to about 1000 atm, even if the sheet diameter is reduced to 2 8' degrees, the magnetic force will not necessarily increase.
On the other hand, in the French manufacturer who increases the maximum lift amount of the valve body, the attraction electromagnetic force is inversely proportional to the two pressures of the gear shaft, so if the maximum lift i is increased, , riff) The electromagnetic force must increase in proportion to the square of k.

In either case, in order to increase the electromagnetic force of the driving engine, the solenoid valve must be made larger, and when considering application to small high-speed engines, the solenoid valve is required to have quick response. Are you completely satisfied? Ii', the FB valve becomes larger and more expensive.

Therefore, the same inventor as the inventor of this application has devised a device that increases the seat diameter without increasing the magnetic force and improves the sharpness of fuel injection by increasing the leak orifice area. .

A cylinder is arranged facing the back of the valve body, and this piston is integrated with the valve body so that a piston having a diameter that is almost the same as the seat diameter of the head of the valve body slides into this cylinder. A pressure balance passage that communicates a back pressure chamber defined by the cylinder and the piston with a fuel supply passage upstream of the seat portion passes through the valve body at its axial center.

In this way, the valve opening force due to the high fuel pressure acting on the valve body head and the valve closing force due to the same fuel pressure acting on the back of the valve body are balanced, and the pressure applied to the valve body drive 11 is reduced. Since the entire influence can be removed, the driving N magnetic force only needs to be relatively small, and with such a solenoid valve, even if the seat diameter is increased, the influence of the force will be small. Therefore, ■1 The seat diameter can be increased without increasing the magnetic force port, and as the seat diameter increases, the leak orifice area expands7, and the injection pressure suddenly decreases to y1.
2) The sharpness of the injection will be improved.

By the way, Fig. 6 (A,) shows 1J, which is the result of including the entire streamline distribution j/l in the state where the valve is in the middle of opening and lifting (described in detail later).In other words, the valve body 43 is lifted to the right, and the high pressure fuel from the pressure chamber 7 is divided into two parts at the head of the valve body 43.
, - one hand escapes to the fuel supply passage 8a through the leak orifice between the valve body 43 and the valve seat 59, and the other hand goes through the pressure balance passage 73 to the back pressure chamber, but the back pressure Since the chamber is a closed space, there is even a bunker where the fuel is trapped.

Therefore, in the passage 55 upstream of the flow gauze flL sheet portion, which coincides with the flow velocity direction of the fuel, the passage center has a bulging distribution, and when fuel having such a streamline distribution flows to the head of the valve body 43, At this time, the distribution of the pressure P acting on the head of the valve body 43 is highest near the axis C of the valve body 43, as shown in FIG. 6(B).

Although the fuel pressure acting near the axis C of the valve body 43 is generally high,
Since the pressure balance passage 73 passes through the axis C of this valve body 43, this axis IL? The high fuel pressure near C reaches the back pressure chamber via the pressure balance passage 73, and this high fuel pressure acts in the valve closing direction (to the left) on the valve body 43.
3, the fuel pressure acting in the valve opening direction (rightward) is relatively low at a portion away from the axis C by more than the opening radius of the pressure balance passage 43.

That is, when the valve body 43 is lifted to open, the fuel pressure acting on the valve body 43 in the valve opening direction is lower than the fuel pressure acting on the valve body 43 in the valve closing direction. This upsets the balance of pressure. Since the valve element driving force corresponding to this fuel pressure difference acts in a direction that completely prevents the valve opening lift of the valve element 43, the dynamic characteristics of the solenoid valve become unstable.

As a countermeasure against this, it is good to increase the load of the elastic member (spring) that biases the valve body 43 in the valve closing direction, but if the set load is increased, the driving electromagnetic force will be increased accordingly. must be made thicker, and there is a fear that this would defeat the self-help purpose of increasing the sheet diameter without increasing the electromagnetic force.

Therefore, the entire purpose of the present invention is to stabilize the dynamic characteristics of the solenoid valve while maintaining the drive electromagnetic force at a constant level.

Therefore, in the present invention, a piston that slides on a cylinder facing the back of the valve body of the valve device is provided integrally with the valve body,
A configuration in which a back pressure chamber defined by a cylinder and a piston is communicated with a fuel supply passage upstream of the seat portion via a pressure balance passage.In addition to the above-mentioned fuel injection control device, the following items are additionally provided. .

That is, the fuel supply passage upstream of the seat part is provided at a position facing away from the opening of the flow guide regulating pressure balance passage, and when the valve body is opened and lifted, the fuel pressure near the maximum due to the relief fuel flowing around the flow guide is provided. acts on the head of the valve body outside the opening, completely regulating the flow of relief fuel.

In this way, near maximum fuel pressure acts on the valve chain in the valve opening direction, whereas relatively low fuel pressure reaches the back pressure chamber via the pressure balance passage, and this pressure is applied to the valve body. Since the valve will act in the direction of fully closing the valve, the driving force of the valve body according to these fuel pressure differences will now act in the direction of fully assisting the valve opening lift of the valve body 431. Based on this theory 8JJ.

FIG. 3 is a schematic configuration diagram of the first embodiment of the present invention, and 4 is a schematic diagram of the first embodiment of the present invention.
．． The two plungers 4a and 4b' shown in Figure 2 (Z are integrated grungers, 30 is a cam that rotates in synchronization with the engine, 31
32 is a support body, 33tj is a holder, 34 is a nozzle holder, 35 is a distance piece that regulates the lift amount of the needle valve 12, 36u/, (The holder 34 and the distance piece A nozzle nut 35 is fixed to the holder 33, 38 is a fuel relief passage to the fuel tank, and 39 is a shim that crushes the valve opening pressure of the nozzle 10.

Reference numeral 40 designates a solenoid valve as a valve device installed in the fuel supply passages 8a, 8b, and an enlarged sectional view thereof is shown in FIG.

In the figure, a cylinder 42K formed in the valve holder 41,
A needle-shaped valve body (needle valve) 43 is slidably fitted, and in the case 44 of the valve holder 41, an armature 46 is fixed around the upper end of the valve body 43 with a screw 45 via a shim 58;
Amateur 46 fully sucked core 47, core 47 fully excited EI
solenoid 48, control crane + II to solenoid 48
A spring 51 that biases the valve body 43 upward in the figure is housed through a terminal 49 to which the p signal is supplied and a stopper 50.

A valve chamber 52 formed facing the lower end of the valve body 43 is connected to a passage 53.
, a chamber 54 communicates with the fuel supply passage 8a, and a passage 55 with the fuel supply passage 8b.

Therefore, during hunting, the upward biasing force of the spring 51 separates the armature 46 from the core 47, and the valve body 43
It separates from the valve seat 59 formed in the pulp holder 41 (opens) and follows the fuel supply passages 8a and 8b completely (7 hours, but the valve is opened).
When the foot crank angle energizes the solenoid 48 from the ff1J control circuit (not shown), the core 47 moves #jEB and sucks the amateur 4G gold 7, and the valve body 43 seats on the valve seat 59 (valve closed). to do).

85 must be raised (・w Such Th, the solenoid 45 of the fitting 4o is frosted, the application 1B, the pressure and the lift operation are all turned off.

That is, when the electric wire valve 4o is energized for a period from 'J'1 to T3, the solenoid valve 4() is closed for a period from 1'2 to T4 with the entire response delay i17.

Returning to FIG. 4, a cylinder 70'fr: is provided at the back of the valve body (upper part of the valve body) facing the VC, and a piston 7 is fitted into the cylinder 7o so that it can be freely compressed with cold pressure.1. It is formed integrally with the H valve body 43.

Back pressure chamber 7 defined by cylinder 70 and piston 7
In order to guide the fuel pressure upstream of the seat portion between the valve body 43 and the valve seat 59, the back pressure chamber 72 and the passage 55 are fully connected to the center of the valve body 43. penetrate.

Therefore, the fuel pressure upstream of the seat portion acting on the head of the valve body 43 and the fuel pressure in the back pressure chamber 72 acting on the back of the valve body 43 are approximately equal.

Here, since the force acting on the valve body is determined by the fuel pressure and the pressure-receiving area on which this fuel pressure acts, it is determined by the fuel pressure upstream of the seat portion of the head of the valve body 43 and the pressure-receiving area of the seat portion. The entire diameter of the piston 71 is set so that the valve opening force and the valve closing force determined by the fuel pressure in the back pressure chamber 72 at the back of the valve body 43 and the pressure receiving area of the piston 71 are approximately balanced.

In the present invention, an orifice 80 is further provided at the opening of the force balance passage 73 in the head of the valve body 43, so that the opening surface t+'ik to the pressure balance passage 73 is made smaller.

On the other hand, the flange portion 82 is arranged so that a flow guide 81 facing the orifice 80 and having an outer diameter larger than the orifice diameter is located in the passage 55 upstream of the seat portion of the head of the valve body 43. Holder 33 and valve holder 41
A communicating hole 83 is entirely provided in this flange portion 82. .

However, in order to ensure a sufficient fuel flow rate in the passage 55 around the flow guide 81, the area of the annular passage 55 is 4.5 mm larger than the leak orifice formed between the valve body 43 and the valve seat 59. The outer diameter of the flow guide 81 is set so that it is more than twice as small.

Reference numeral 56 on the upper part of the case 44 is a stopper for fixing the cylinder 7 Qf, and reference numeral 57 is a stone or lock for fixing the stopper 56 by screwing.

Also, 60 is a fuel relief passage, group ro 1, passage 62.
, spring chamber 63, and amateur chamber 6 via passage 64.
5 and returns excess fuel to the fuel tank. 66 is a seal ring.

The other constituent elements are the same as those in Fig. 1.2, and the same reference numerals are used throughout to omit the explanation.

The effect of the above configuration will be explained.

The fuel in the fuel tank that is pre-pressurized by the fuel pump is
Fuel is supplied from the fuel supply passage 8a to the pressure chamber 7 via the chamber 54, the passage 5:1, the leak orifice, and the passage 55.

When the cam 3 and the shifter 4, which rotate in synchronization with the engine, descend and begin to pressurize the fuel in the pressure chamber 7, the fuel pressure changes in the reverse order of the fuel supply described above, that is, the fuel supply From passage b to passage 55, leak orifice, passage 53, chamber 5
4 to the fuel supply passage 8a, and since the flow guide 81 and the orifice 80 opening are separated from the ship, the external pressure flows through the orifice 80 and the pressure balance passage 73.
1 and reaches the back pressure chamber 72.

The fuel pressure upstream of the seat part of the head of the valve body 43 and the fuel pressure in the back pressure chamber 72 at the back of the valve body 43 are approximately equal, and the pressure receiving area on which these fuel pressures act is also the same between the head of the valve body 43 and the back of the valve body 43. Since the piston diameters are set to be approximately equal, the valve body 4
Since the valve opening force acting on the head of the valve body 43 and the valve closing force acting on the back of the valve body 43 cancel each other out, the spring 5 of the jF body 43
It is separated from the valve seat 59 only by the upward biasing force of J in the figure.

In other words, when the fuel pressure from the pressure chamber 7 is low (t)iJ, the fuel pressure is balanced between the head and back of the valve body 430, so the electromagnetic force that drives the valve body 43 of the solenoid valve 40 in the direction of fully closing the valve body 430 increases. The difference in weight between the valve body 43 and the armature 46 is enough to counter the viscosity of the fuel, and the relatively small 'Ri
, open and close is driven regardless of magnetic force or high-pressure fuel.

Therefore, even if the seat diameter is increased, drive-7#.

The force can be kept relatively small, and the seat diameter is set large in this example.

Therefore, when the solenoid 48 is energized while the plunger 4 is descending, the valve body 43 is lifted by a small electromagnetic force and is seated on the valve seat 59 (closed).

Since communication between the fuel supply passages 8a and 8b is cut off by this valve closing, the fuel in the pressure chamber 7 is confined and the fuel pressure increases completely. This fuel pressure reaches the needle chamber 11 through the fuel passage 9,
When the pressure (injection pressure) in the needle chamber J1 is increased to exceed the valve opening pressure of the nozzle 1o, the needle pulp 12 is lifted upward and fuel is injected from the injection hole 4. As the injection pressure increases, it increases to the upper row.

When the voltage application to the solenoid 48 is finished at a crank angle of PJr constant -f, the valve body 43 begins to open in the direction l-k, but the outside diameter of the flow guide 81 is V and the opening diameter of the orifice 80 is Since the flow guide 81 is also set large, the high pressure fuel is connected to the leak orifice from the passage 55 around the flow guide 81 and flows smoothly.

FIG. 7 (A
), the streamline distribution is as shown in the figure around the flow guide 81, and there are 43 valve bodies 1! , l() As shown in FIG. When the fuel pressure is low, the fuel pressure has a peak outside of the low fuel pressure.

That is, the fuel pressure near the peak τj acts on the valve body 43iC just outside the opening of the orifice 80 in the valve opening direction.

On the other hand, from the opening of the orifice 80, the pressure balance passage 73
As described above, the fuel pressure reaching the back pressure chamber 72 via the back pressure chamber 72 is a fuel pressure with a reduced pressure near the axis C, and this low fuel pressure moves in the valve closing direction Vc of the valve body 43.

This unbalance of acting force due to the difference in fuel pressure between the head of the valve body 43 and the back of the valve body 43 increases the opening force when the valve body 43 is lifted to open, so the valve body 43 quickly opens. Lift the valve to the open position.

Due to this valve opening, high-pressure fuel escapes into the fuel supply passage 8a via a leak orifice formed between the valve body 43 and the valve seat 59, but the area of this leak orifice is determined by the speed at which the fuel pressure is released. Therefore, in this embodiment where the seat diameter is completely increased, the orifice area expands due to the increase in the seat diameter, and therefore the injection pressure suddenly increases after the valve opens, as shown in Figure 5. The pressure falls below the closing pressure of the nozzle 10. .

Therefore, the injection rate also increases due to this rapid decrease in injection pressure +Cf>
In addition, as shown in the figure, there is a sharp fall at the end of injection, shortening the time until the end of injection.

Therefore, since the valve opening drive of the valve body 43 is stable, in order to correct the unbalance of the acting force, e(, the spring 51
There is no need to increase the biasing force, and as a result, the magnetic force can be kept small.

As described above, according to the present invention, the flow guide is provided in the fuel supply passage upstream of the seat portion at a position facing away from the opening of the pressure balance passage, and when the valve body is opened, the flow The flow of the relief fuel is regulated so that the fuel pressure near the maximum due to the relief fuel flowing around the guide acts on the head of the valve body outside the opening, thereby reducing the imbalance of forces acting on the head and back of the valve body. However, it works to assist the opening lift of the valve body, without increasing the driving electromagnetic force.
The effect is that the dynamic characteristics of the solenoid valve can be completely improved.

In addition, by stabilizing the dynamic characteristics of the solenoid valve, it is possible to obtain the effect of improving the sharpness of injection when the valve is opened. .

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a unit injector used in a conventional device, and FIG. 2 is a cross-sectional view of the main part of FIG. 1. . FIG. 3 is a schematic configuration diagram of a unit injector according to the first embodiment of the present invention, FIG. 4 is an enlarged sectional view of a solenoid valve, and FIG. 5 is a diagram showing 111. It is a figure showing each %ul of the valve body lift, injection pressure, and injection rate of magnetic valve 1. Figure 6 (A) is an explanatory diagram of the effect of conventional mounting, and Figure 6 (B)
7(A) is a diagram showing the pressure distribution acting on the valve body head, FIG. 7(A) is an explanatory diagram of the action according to the present invention, and FIG. FIG. 4...79 lunge, 7...pressure chamber, 8a, 8b.
... Fuel supply passage, 10 ... Nozzle nope 4 () ... Electromagnetic seat, 43 ... Valve body, 48 ... Solenoid, 51
...Spring, 55...Passage, 70...Cylinder, 7J...Piston, 72...Back pressure chamber, 73...
・Pressure balance passage, 80... Orifice, 81...
・Flow force (de. Patent applicant Nissan Automatic M1 Co., Ltd.! ・ ゛. Agent Patent attorney Masaki Goto' 11 ゛・ 1st "'] Figure 2 Figure 5 Figure 6 (A ) to the 61'X1 (BJ

Claims (1)

[Claims] fi+ A plunger that reciprocates in synchronization with the engine, a pressure chamber formed facing one end of the plunger, a nozzle communicating with the pressure chamber and opening at a predetermined pressure or higher, and a nozzle in the pressure chamber that opens at a predetermined pressure or higher. The valve body is normally biased in the valve-opening direction by the elastic phase, and when the solenoid is energized, the valve body lifts in the valve-closing direction to close the valve. At the same time, a cylinder facing the back of the valve body is provided integrally with the sliding piston metal valve body, and the back pressure chamber defined by the cylinder and piston passes through the entire pressure balance passage to the fuel upstream of the seat part. In a fuel injection control device that is fully equipped with a valve device that communicates with a supply passage and that fully opens and closes the valve device depending on the operating state of the engine, a flow guide is placed in the fuel supply passage upstream of the seat part and separated from the opening of the pressure balance passage. The vent valve is provided at a position facing the valve body, and regulates the flow of relief fuel so that when the valve body is opened, the fuel pressure near the maximum due to the relief fuel flowing around the flow guide acts on the head of the valve body on the outside of the opening. A fuel injection control device characterized by: (2) A pressure balance passage is formed through the center of the axis of the valve body, the flow guide faces the opening of the pressure balance passage, and has an outer diameter larger than the opening diameter of the pressure balance passage. A fuel injection control device according to claim 1, characterized in that: